/* * Copyright (C) 2007 Oracle. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include #include #include #include #include #include #include #include #include #include #include "hash.h" #include "tree-log.h" #include "disk-io.h" #include "print-tree.h" #include "volumes.h" #include "raid56.h" #include "locking.h" #include "free-space-cache.h" #include "math.h" #include "sysfs.h" #include "qgroup.h" #undef SCRAMBLE_DELAYED_REFS /* * control flags for do_chunk_alloc's force field * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk * if we really need one. * * CHUNK_ALLOC_LIMITED means to only try and allocate one * if we have very few chunks already allocated. This is * used as part of the clustering code to help make sure * we have a good pool of storage to cluster in, without * filling the FS with empty chunks * * CHUNK_ALLOC_FORCE means it must try to allocate one * */ enum { CHUNK_ALLOC_NO_FORCE = 0, CHUNK_ALLOC_LIMITED = 1, CHUNK_ALLOC_FORCE = 2, }; /* * Control how reservations are dealt with. * * RESERVE_FREE - freeing a reservation. * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for * ENOSPC accounting * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update * bytes_may_use as the ENOSPC accounting is done elsewhere */ enum { RESERVE_FREE = 0, RESERVE_ALLOC = 1, RESERVE_ALLOC_NO_ACCOUNT = 2, }; static int update_block_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, int alloc); static int __btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, u64 parent, u64 root_objectid, u64 owner_objectid, u64 owner_offset, int refs_to_drop, struct btrfs_delayed_extent_op *extra_op); static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op, struct extent_buffer *leaf, struct btrfs_extent_item *ei); static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent, u64 root_objectid, u64 flags, u64 owner, u64 offset, struct btrfs_key *ins, int ref_mod); static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent, u64 root_objectid, u64 flags, struct btrfs_disk_key *key, int level, struct btrfs_key *ins, int no_quota); static int do_chunk_alloc(struct btrfs_trans_handle *trans, struct btrfs_root *extent_root, u64 flags, int force); static int find_next_key(struct btrfs_path *path, int level, struct btrfs_key *key); static void dump_space_info(struct btrfs_space_info *info, u64 bytes, int dump_block_groups); static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache, u64 num_bytes, int reserve, int delalloc); static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes); int btrfs_pin_extent(struct btrfs_root *root, u64 bytenr, u64 num_bytes, int reserved); static noinline int block_group_cache_done(struct btrfs_block_group_cache *cache) { smp_mb(); return cache->cached == BTRFS_CACHE_FINISHED || cache->cached == BTRFS_CACHE_ERROR; } static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits) { return (cache->flags & bits) == bits; } static void btrfs_get_block_group(struct btrfs_block_group_cache *cache) { atomic_inc(&cache->count); } void btrfs_put_block_group(struct btrfs_block_group_cache *cache) { if (atomic_dec_and_test(&cache->count)) { WARN_ON(cache->pinned > 0); WARN_ON(cache->reserved > 0); kfree(cache->free_space_ctl); kfree(cache); } } /* * this adds the block group to the fs_info rb tree for the block group * cache */ static int btrfs_add_block_group_cache(struct btrfs_fs_info *info, struct btrfs_block_group_cache *block_group) { struct rb_node **p; struct rb_node *parent = NULL; struct btrfs_block_group_cache *cache; spin_lock(&info->block_group_cache_lock); p = &info->block_group_cache_tree.rb_node; while (*p) { parent = *p; cache = rb_entry(parent, struct btrfs_block_group_cache, cache_node); if (block_group->key.objectid < cache->key.objectid) { p = &(*p)->rb_left; } else if (block_group->key.objectid > cache->key.objectid) { p = &(*p)->rb_right; } else { spin_unlock(&info->block_group_cache_lock); return -EEXIST; } } rb_link_node(&block_group->cache_node, parent, p); rb_insert_color(&block_group->cache_node, &info->block_group_cache_tree); if (info->first_logical_byte > block_group->key.objectid) info->first_logical_byte = block_group->key.objectid; spin_unlock(&info->block_group_cache_lock); return 0; } /* * This will return the block group at or after bytenr if contains is 0, else * it will return the block group that contains the bytenr */ static struct btrfs_block_group_cache * block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr, int contains) { struct btrfs_block_group_cache *cache, *ret = NULL; struct rb_node *n; u64 end, start; spin_lock(&info->block_group_cache_lock); n = info->block_group_cache_tree.rb_node; while (n) { cache = rb_entry(n, struct btrfs_block_group_cache, cache_node); end = cache->key.objectid + cache->key.offset - 1; start = cache->key.objectid; if (bytenr < start) { if (!contains && (!ret || start < ret->key.objectid)) ret = cache; n = n->rb_left; } else if (bytenr > start) { if (contains && bytenr <= end) { ret = cache; break; } n = n->rb_right; } else { ret = cache; break; } } if (ret) { btrfs_get_block_group(ret); if (bytenr == 0 && info->first_logical_byte > ret->key.objectid) info->first_logical_byte = ret->key.objectid; } spin_unlock(&info->block_group_cache_lock); return ret; } static int add_excluded_extent(struct btrfs_root *root, u64 start, u64 num_bytes) { u64 end = start + num_bytes - 1; set_extent_bits(&root->fs_info->freed_extents[0], start, end, EXTENT_UPTODATE, GFP_NOFS); set_extent_bits(&root->fs_info->freed_extents[1], start, end, EXTENT_UPTODATE, GFP_NOFS); return 0; } static void free_excluded_extents(struct btrfs_root *root, struct btrfs_block_group_cache *cache) { u64 start, end; start = cache->key.objectid; end = start + cache->key.offset - 1; clear_extent_bits(&root->fs_info->freed_extents[0], start, end, EXTENT_UPTODATE, GFP_NOFS); clear_extent_bits(&root->fs_info->freed_extents[1], start, end, EXTENT_UPTODATE, GFP_NOFS); } static int exclude_super_stripes(struct btrfs_root *root, struct btrfs_block_group_cache *cache) { u64 bytenr; u64 *logical; int stripe_len; int i, nr, ret; if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) { stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid; cache->bytes_super += stripe_len; ret = add_excluded_extent(root, cache->key.objectid, stripe_len); if (ret) return ret; } for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) { bytenr = btrfs_sb_offset(i); ret = btrfs_rmap_block(&root->fs_info->mapping_tree, cache->key.objectid, bytenr, 0, &logical, &nr, &stripe_len); if (ret) return ret; while (nr--) { u64 start, len; if (logical[nr] > cache->key.objectid + cache->key.offset) continue; if (logical[nr] + stripe_len <= cache->key.objectid) continue; start = logical[nr]; if (start < cache->key.objectid) { start = cache->key.objectid; len = (logical[nr] + stripe_len) - start; } else { len = min_t(u64, stripe_len, cache->key.objectid + cache->key.offset - start); } cache->bytes_super += len; ret = add_excluded_extent(root, start, len); if (ret) { kfree(logical); return ret; } } kfree(logical); } return 0; } static struct btrfs_caching_control * get_caching_control(struct btrfs_block_group_cache *cache) { struct btrfs_caching_control *ctl; spin_lock(&cache->lock); if (!cache->caching_ctl) { spin_unlock(&cache->lock); return NULL; } ctl = cache->caching_ctl; atomic_inc(&ctl->count); spin_unlock(&cache->lock); return ctl; } static void put_caching_control(struct btrfs_caching_control *ctl) { if (atomic_dec_and_test(&ctl->count)) kfree(ctl); } #ifdef CONFIG_BTRFS_DEBUG static void fragment_free_space(struct btrfs_root *root, struct btrfs_block_group_cache *block_group) { u64 start = block_group->key.objectid; u64 len = block_group->key.offset; u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ? root->nodesize : root->sectorsize; u64 step = chunk << 1; while (len > chunk) { btrfs_remove_free_space(block_group, start, chunk); start += step; if (len < step) len = 0; else len -= step; } } #endif /* * this is only called by cache_block_group, since we could have freed extents * we need to check the pinned_extents for any extents that can't be used yet * since their free space will be released as soon as the transaction commits. */ static u64 add_new_free_space(struct btrfs_block_group_cache *block_group, struct btrfs_fs_info *info, u64 start, u64 end) { u64 extent_start, extent_end, size, total_added = 0; int ret; while (start < end) { ret = find_first_extent_bit(info->pinned_extents, start, &extent_start, &extent_end, EXTENT_DIRTY | EXTENT_UPTODATE, NULL); if (ret) break; if (extent_start <= start) { start = extent_end + 1; } else if (extent_start > start && extent_start < end) { size = extent_start - start; total_added += size; ret = btrfs_add_free_space(block_group, start, size); BUG_ON(ret); /* -ENOMEM or logic error */ start = extent_end + 1; } else { break; } } if (start < end) { size = end - start; total_added += size; ret = btrfs_add_free_space(block_group, start, size); BUG_ON(ret); /* -ENOMEM or logic error */ } return total_added; } static noinline void caching_thread(struct btrfs_work *work) { struct btrfs_block_group_cache *block_group; struct btrfs_fs_info *fs_info; struct btrfs_caching_control *caching_ctl; struct btrfs_root *extent_root; struct btrfs_path *path; struct extent_buffer *leaf; struct btrfs_key key; u64 total_found = 0; u64 last = 0; u32 nritems; int ret = -ENOMEM; bool wakeup = true; caching_ctl = container_of(work, struct btrfs_caching_control, work); block_group = caching_ctl->block_group; fs_info = block_group->fs_info; extent_root = fs_info->extent_root; path = btrfs_alloc_path(); if (!path) goto out; last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET); #ifdef CONFIG_BTRFS_DEBUG /* * If we're fragmenting we don't want to make anybody think we can * allocate from this block group until we've had a chance to fragment * the free space. */ if (btrfs_should_fragment_free_space(extent_root, block_group)) wakeup = false; #endif /* * We don't want to deadlock with somebody trying to allocate a new * extent for the extent root while also trying to search the extent * root to add free space. So we skip locking and search the commit * root, since its read-only */ path->skip_locking = 1; path->search_commit_root = 1; path->reada = 1; key.objectid = last; key.offset = 0; key.type = BTRFS_EXTENT_ITEM_KEY; again: mutex_lock(&caching_ctl->mutex); /* need to make sure the commit_root doesn't disappear */ down_read(&fs_info->commit_root_sem); next: ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); if (ret < 0) goto err; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); while (1) { if (btrfs_fs_closing(fs_info) > 1) { last = (u64)-1; break; } if (path->slots[0] < nritems) { btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); } else { ret = find_next_key(path, 0, &key); if (ret) break; if (need_resched() || rwsem_is_contended(&fs_info->commit_root_sem)) { if (wakeup) caching_ctl->progress = last; btrfs_release_path(path); up_read(&fs_info->commit_root_sem); mutex_unlock(&caching_ctl->mutex); cond_resched(); goto again; } ret = btrfs_next_leaf(extent_root, path); if (ret < 0) goto err; if (ret) break; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); continue; } if (key.objectid < last) { key.objectid = last; key.offset = 0; key.type = BTRFS_EXTENT_ITEM_KEY; if (wakeup) caching_ctl->progress = last; btrfs_release_path(path); goto next; } if (key.objectid < block_group->key.objectid) { path->slots[0]++; continue; } if (key.objectid >= block_group->key.objectid + block_group->key.offset) break; if (key.type == BTRFS_EXTENT_ITEM_KEY || key.type == BTRFS_METADATA_ITEM_KEY) { total_found += add_new_free_space(block_group, fs_info, last, key.objectid); if (key.type == BTRFS_METADATA_ITEM_KEY) last = key.objectid + fs_info->tree_root->nodesize; else last = key.objectid + key.offset; if (total_found > (1024 * 1024 * 2)) { total_found = 0; if (wakeup) wake_up(&caching_ctl->wait); } } path->slots[0]++; } ret = 0; total_found += add_new_free_space(block_group, fs_info, last, block_group->key.objectid + block_group->key.offset); spin_lock(&block_group->lock); block_group->caching_ctl = NULL; block_group->cached = BTRFS_CACHE_FINISHED; spin_unlock(&block_group->lock); #ifdef CONFIG_BTRFS_DEBUG if (btrfs_should_fragment_free_space(extent_root, block_group)) { u64 bytes_used; spin_lock(&block_group->space_info->lock); spin_lock(&block_group->lock); bytes_used = block_group->key.offset - btrfs_block_group_used(&block_group->item); block_group->space_info->bytes_used += bytes_used >> 1; spin_unlock(&block_group->lock); spin_unlock(&block_group->space_info->lock); fragment_free_space(extent_root, block_group); } #endif caching_ctl->progress = (u64)-1; err: btrfs_free_path(path); up_read(&fs_info->commit_root_sem); free_excluded_extents(extent_root, block_group); mutex_unlock(&caching_ctl->mutex); out: if (ret) { spin_lock(&block_group->lock); block_group->caching_ctl = NULL; block_group->cached = BTRFS_CACHE_ERROR; spin_unlock(&block_group->lock); } wake_up(&caching_ctl->wait); put_caching_control(caching_ctl); btrfs_put_block_group(block_group); } static int cache_block_group(struct btrfs_block_group_cache *cache, int load_cache_only) { DEFINE_WAIT(wait); struct btrfs_fs_info *fs_info = cache->fs_info; struct btrfs_caching_control *caching_ctl; int ret = 0; caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS); if (!caching_ctl) return -ENOMEM; INIT_LIST_HEAD(&caching_ctl->list); mutex_init(&caching_ctl->mutex); init_waitqueue_head(&caching_ctl->wait); caching_ctl->block_group = cache; caching_ctl->progress = cache->key.objectid; atomic_set(&caching_ctl->count, 1); btrfs_init_work(&caching_ctl->work, btrfs_cache_helper, caching_thread, NULL, NULL); spin_lock(&cache->lock); /* * This should be a rare occasion, but this could happen I think in the * case where one thread starts to load the space cache info, and then * some other thread starts a transaction commit which tries to do an * allocation while the other thread is still loading the space cache * info. The previous loop should have kept us from choosing this block * group, but if we've moved to the state where we will wait on caching * block groups we need to first check if we're doing a fast load here, * so we can wait for it to finish, otherwise we could end up allocating * from a block group who's cache gets evicted for one reason or * another. */ while (cache->cached == BTRFS_CACHE_FAST) { struct btrfs_caching_control *ctl; ctl = cache->caching_ctl; atomic_inc(&ctl->count); prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE); spin_unlock(&cache->lock); schedule(); finish_wait(&ctl->wait, &wait); put_caching_control(ctl); spin_lock(&cache->lock); } if (cache->cached != BTRFS_CACHE_NO) { spin_unlock(&cache->lock); kfree(caching_ctl); return 0; } WARN_ON(cache->caching_ctl); cache->caching_ctl = caching_ctl; cache->cached = BTRFS_CACHE_FAST; spin_unlock(&cache->lock); if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) { mutex_lock(&caching_ctl->mutex); ret = load_free_space_cache(fs_info, cache); spin_lock(&cache->lock); if (ret == 1) { cache->caching_ctl = NULL; cache->cached = BTRFS_CACHE_FINISHED; cache->last_byte_to_unpin = (u64)-1; caching_ctl->progress = (u64)-1; } else { if (load_cache_only) { cache->caching_ctl = NULL; cache->cached = BTRFS_CACHE_NO; } else { cache->cached = BTRFS_CACHE_STARTED; cache->has_caching_ctl = 1; } } spin_unlock(&cache->lock); #ifdef CONFIG_BTRFS_DEBUG if (ret == 1 && btrfs_should_fragment_free_space(fs_info->extent_root, cache)) { u64 bytes_used; spin_lock(&cache->space_info->lock); spin_lock(&cache->lock); bytes_used = cache->key.offset - btrfs_block_group_used(&cache->item); cache->space_info->bytes_used += bytes_used >> 1; spin_unlock(&cache->lock); spin_unlock(&cache->space_info->lock); fragment_free_space(fs_info->extent_root, cache); } #endif mutex_unlock(&caching_ctl->mutex); wake_up(&caching_ctl->wait); if (ret == 1) { put_caching_control(caching_ctl); free_excluded_extents(fs_info->extent_root, cache); return 0; } } else { /* * We are not going to do the fast caching, set cached to the * appropriate value and wakeup any waiters. */ spin_lock(&cache->lock); if (load_cache_only) { cache->caching_ctl = NULL; cache->cached = BTRFS_CACHE_NO; } else { cache->cached = BTRFS_CACHE_STARTED; cache->has_caching_ctl = 1; } spin_unlock(&cache->lock); wake_up(&caching_ctl->wait); } if (load_cache_only) { put_caching_control(caching_ctl); return 0; } down_write(&fs_info->commit_root_sem); atomic_inc(&caching_ctl->count); list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups); up_write(&fs_info->commit_root_sem); btrfs_get_block_group(cache); btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work); return ret; } /* * return the block group that starts at or after bytenr */ static struct btrfs_block_group_cache * btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr) { struct btrfs_block_group_cache *cache; cache = block_group_cache_tree_search(info, bytenr, 0); return cache; } /* * return the block group that contains the given bytenr */ struct btrfs_block_group_cache *btrfs_lookup_block_group( struct btrfs_fs_info *info, u64 bytenr) { struct btrfs_block_group_cache *cache; cache = block_group_cache_tree_search(info, bytenr, 1); return cache; } static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info, u64 flags) { struct list_head *head = &info->space_info; struct btrfs_space_info *found; flags &= BTRFS_BLOCK_GROUP_TYPE_MASK; rcu_read_lock(); list_for_each_entry_rcu(found, head, list) { if (found->flags & flags) { rcu_read_unlock(); return found; } } rcu_read_unlock(); return NULL; } /* * after adding space to the filesystem, we need to clear the full flags * on all the space infos. */ void btrfs_clear_space_info_full(struct btrfs_fs_info *info) { struct list_head *head = &info->space_info; struct btrfs_space_info *found; rcu_read_lock(); list_for_each_entry_rcu(found, head, list) found->full = 0; rcu_read_unlock(); } /* simple helper to search for an existing data extent at a given offset */ int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len) { int ret; struct btrfs_key key; struct btrfs_path *path; path = btrfs_alloc_path(); if (!path) return -ENOMEM; key.objectid = start; key.offset = len; key.type = BTRFS_EXTENT_ITEM_KEY; ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path, 0, 0); btrfs_free_path(path); return ret; } /* * helper function to lookup reference count and flags of a tree block. * * the head node for delayed ref is used to store the sum of all the * reference count modifications queued up in the rbtree. the head * node may also store the extent flags to set. This way you can check * to see what the reference count and extent flags would be if all of * the delayed refs are not processed. */ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 offset, int metadata, u64 *refs, u64 *flags) { struct btrfs_delayed_ref_head *head; struct btrfs_delayed_ref_root *delayed_refs; struct btrfs_path *path; struct btrfs_extent_item *ei; struct extent_buffer *leaf; struct btrfs_key key; u32 item_size; u64 num_refs; u64 extent_flags; int ret; /* * If we don't have skinny metadata, don't bother doing anything * different */ if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) { offset = root->nodesize; metadata = 0; } path = btrfs_alloc_path(); if (!path) return -ENOMEM; if (!trans) { path->skip_locking = 1; path->search_commit_root = 1; } search_again: key.objectid = bytenr; key.offset = offset; if (metadata) key.type = BTRFS_METADATA_ITEM_KEY; else key.type = BTRFS_EXTENT_ITEM_KEY; ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path, 0, 0); if (ret < 0) goto out_free; if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) { if (path->slots[0]) { path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid == bytenr && key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == root->nodesize) ret = 0; } } if (ret == 0) { leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); if (item_size >= sizeof(*ei)) { ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); num_refs = btrfs_extent_refs(leaf, ei); extent_flags = btrfs_extent_flags(leaf, ei); } else { #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 struct btrfs_extent_item_v0 *ei0; BUG_ON(item_size != sizeof(*ei0)); ei0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item_v0); num_refs = btrfs_extent_refs_v0(leaf, ei0); /* FIXME: this isn't correct for data */ extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; #else BUG(); #endif } BUG_ON(num_refs == 0); } else { num_refs = 0; extent_flags = 0; ret = 0; } if (!trans) goto out; delayed_refs = &trans->transaction->delayed_refs; spin_lock(&delayed_refs->lock); head = btrfs_find_delayed_ref_head(trans, bytenr); if (head) { if (!mutex_trylock(&head->mutex)) { atomic_inc(&head->node.refs); spin_unlock(&delayed_refs->lock); btrfs_release_path(path); /* * Mutex was contended, block until it's released and try * again */ mutex_lock(&head->mutex); mutex_unlock(&head->mutex); btrfs_put_delayed_ref(&head->node); goto search_again; } spin_lock(&head->lock); if (head->extent_op && head->extent_op->update_flags) extent_flags |= head->extent_op->flags_to_set; else BUG_ON(num_refs == 0); num_refs += head->node.ref_mod; spin_unlock(&head->lock); mutex_unlock(&head->mutex); } spin_unlock(&delayed_refs->lock); out: WARN_ON(num_refs == 0); if (refs) *refs = num_refs; if (flags) *flags = extent_flags; out_free: btrfs_free_path(path); return ret; } /* * Back reference rules. Back refs have three main goals: * * 1) differentiate between all holders of references to an extent so that * when a reference is dropped we can make sure it was a valid reference * before freeing the extent. * * 2) Provide enough information to quickly find the holders of an extent * if we notice a given block is corrupted or bad. * * 3) Make it easy to migrate blocks for FS shrinking or storage pool * maintenance. This is actually the same as #2, but with a slightly * different use case. * * There are two kinds of back refs. The implicit back refs is optimized * for pointers in non-shared tree blocks. For a given pointer in a block, * back refs of this kind provide information about the block's owner tree * and the pointer's key. These information allow us to find the block by * b-tree searching. The full back refs is for pointers in tree blocks not * referenced by their owner trees. The location of tree block is recorded * in the back refs. Actually the full back refs is generic, and can be * used in all cases the implicit back refs is used. The major shortcoming * of the full back refs is its overhead. Every time a tree block gets * COWed, we have to update back refs entry for all pointers in it. * * For a newly allocated tree block, we use implicit back refs for * pointers in it. This means most tree related operations only involve * implicit back refs. For a tree block created in old transaction, the * only way to drop a reference to it is COW it. So we can detect the * event that tree block loses its owner tree's reference and do the * back refs conversion. * * When a tree block is COW'd through a tree, there are four cases: * * The reference count of the block is one and the tree is the block's * owner tree. Nothing to do in this case. * * The reference count of the block is one and the tree is not the * block's owner tree. In this case, full back refs is used for pointers * in the block. Remove these full back refs, add implicit back refs for * every pointers in the new block. * * The reference count of the block is greater than one and the tree is * the block's owner tree. In this case, implicit back refs is used for * pointers in the block. Add full back refs for every pointers in the * block, increase lower level extents' reference counts. The original * implicit back refs are entailed to the new block. * * The reference count of the block is greater than one and the tree is * not the block's owner tree. Add implicit back refs for every pointer in * the new block, increase lower level extents' reference count. * * Back Reference Key composing: * * The key objectid corresponds to the first byte in the extent, * The key type is used to differentiate between types of back refs. * There are different meanings of the key offset for different types * of back refs. * * File extents can be referenced by: * * - multiple snapshots, subvolumes, or different generations in one subvol * - different files inside a single subvolume * - different offsets inside a file (bookend extents in file.c) * * The extent ref structure for the implicit back refs has fields for: * * - Objectid of the subvolume root * - objectid of the file holding the reference * - original offset in the file * - how many bookend extents * * The key offset for the implicit back refs is hash of the first * three fields. * * The extent ref structure for the full back refs has field for: * * - number of pointers in the tree leaf * * The key offset for the implicit back refs is the first byte of * the tree leaf * * When a file extent is allocated, The implicit back refs is used. * the fields are filled in: * * (root_key.objectid, inode objectid, offset in file, 1) * * When a file extent is removed file truncation, we find the * corresponding implicit back refs and check the following fields: * * (btrfs_header_owner(leaf), inode objectid, offset in file) * * Btree extents can be referenced by: * * - Different subvolumes * * Both the implicit back refs and the full back refs for tree blocks * only consist of key. The key offset for the implicit back refs is * objectid of block's owner tree. The key offset for the full back refs * is the first byte of parent block. * * When implicit back refs is used, information about the lowest key and * level of the tree block are required. These information are stored in * tree block info structure. */ #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 static int convert_extent_item_v0(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 owner, u32 extra_size) { struct btrfs_extent_item *item; struct btrfs_extent_item_v0 *ei0; struct btrfs_extent_ref_v0 *ref0; struct btrfs_tree_block_info *bi; struct extent_buffer *leaf; struct btrfs_key key; struct btrfs_key found_key; u32 new_size = sizeof(*item); u64 refs; int ret; leaf = path->nodes[0]; BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0)); btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); ei0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item_v0); refs = btrfs_extent_refs_v0(leaf, ei0); if (owner == (u64)-1) { while (1) { if (path->slots[0] >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret < 0) return ret; BUG_ON(ret > 0); /* Corruption */ leaf = path->nodes[0]; } btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); BUG_ON(key.objectid != found_key.objectid); if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) { path->slots[0]++; continue; } ref0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref_v0); owner = btrfs_ref_objectid_v0(leaf, ref0); break; } } btrfs_release_path(path); if (owner < BTRFS_FIRST_FREE_OBJECTID) new_size += sizeof(*bi); new_size -= sizeof(*ei0); ret = btrfs_search_slot(trans, root, &key, path, new_size + extra_size, 1); if (ret < 0) return ret; BUG_ON(ret); /* Corruption */ btrfs_extend_item(root, path, new_size); leaf = path->nodes[0]; item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); btrfs_set_extent_refs(leaf, item, refs); /* FIXME: get real generation */ btrfs_set_extent_generation(leaf, item, 0); if (owner < BTRFS_FIRST_FREE_OBJECTID) { btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_TREE_BLOCK | BTRFS_BLOCK_FLAG_FULL_BACKREF); bi = (struct btrfs_tree_block_info *)(item + 1); /* FIXME: get first key of the block */ memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi)); btrfs_set_tree_block_level(leaf, bi, (int)owner); } else { btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA); } btrfs_mark_buffer_dirty(leaf); return 0; } #endif static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset) { u32 high_crc = ~(u32)0; u32 low_crc = ~(u32)0; __le64 lenum; lenum = cpu_to_le64(root_objectid); high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum)); lenum = cpu_to_le64(owner); low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum)); lenum = cpu_to_le64(offset); low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum)); return ((u64)high_crc << 31) ^ (u64)low_crc; } static u64 hash_extent_data_ref_item(struct extent_buffer *leaf, struct btrfs_extent_data_ref *ref) { return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref), btrfs_extent_data_ref_objectid(leaf, ref), btrfs_extent_data_ref_offset(leaf, ref)); } static int match_extent_data_ref(struct extent_buffer *leaf, struct btrfs_extent_data_ref *ref, u64 root_objectid, u64 owner, u64 offset) { if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid || btrfs_extent_data_ref_objectid(leaf, ref) != owner || btrfs_extent_data_ref_offset(leaf, ref) != offset) return 0; return 1; } static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 parent, u64 root_objectid, u64 owner, u64 offset) { struct btrfs_key key; struct btrfs_extent_data_ref *ref; struct extent_buffer *leaf; u32 nritems; int ret; int recow; int err = -ENOENT; key.objectid = bytenr; if (parent) { key.type = BTRFS_SHARED_DATA_REF_KEY; key.offset = parent; } else { key.type = BTRFS_EXTENT_DATA_REF_KEY; key.offset = hash_extent_data_ref(root_objectid, owner, offset); } again: recow = 0; ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret < 0) { err = ret; goto fail; } if (parent) { if (!ret) return 0; #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 key.type = BTRFS_EXTENT_REF_V0_KEY; btrfs_release_path(path); ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret < 0) { err = ret; goto fail; } if (!ret) return 0; #endif goto fail; } leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); while (1) { if (path->slots[0] >= nritems) { ret = btrfs_next_leaf(root, path); if (ret < 0) err = ret; if (ret) goto fail; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); recow = 1; } btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.objectid != bytenr || key.type != BTRFS_EXTENT_DATA_REF_KEY) goto fail; ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_data_ref); if (match_extent_data_ref(leaf, ref, root_objectid, owner, offset)) { if (recow) { btrfs_release_path(path); goto again; } err = 0; break; } path->slots[0]++; } fail: return err; } static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 parent, u64 root_objectid, u64 owner, u64 offset, int refs_to_add) { struct btrfs_key key; struct extent_buffer *leaf; u32 size; u32 num_refs; int ret; key.objectid = bytenr; if (parent) { key.type = BTRFS_SHARED_DATA_REF_KEY; key.offset = parent; size = sizeof(struct btrfs_shared_data_ref); } else { key.type = BTRFS_EXTENT_DATA_REF_KEY; key.offset = hash_extent_data_ref(root_objectid, owner, offset); size = sizeof(struct btrfs_extent_data_ref); } ret = btrfs_insert_empty_item(trans, root, path, &key, size); if (ret && ret != -EEXIST) goto fail; leaf = path->nodes[0]; if (parent) { struct btrfs_shared_data_ref *ref; ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_shared_data_ref); if (ret == 0) { btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add); } else { num_refs = btrfs_shared_data_ref_count(leaf, ref); num_refs += refs_to_add; btrfs_set_shared_data_ref_count(leaf, ref, num_refs); } } else { struct btrfs_extent_data_ref *ref; while (ret == -EEXIST) { ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_data_ref); if (match_extent_data_ref(leaf, ref, root_objectid, owner, offset)) break; btrfs_release_path(path); key.offset++; ret = btrfs_insert_empty_item(trans, root, path, &key, size); if (ret && ret != -EEXIST) goto fail; leaf = path->nodes[0]; } ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_data_ref); if (ret == 0) { btrfs_set_extent_data_ref_root(leaf, ref, root_objectid); btrfs_set_extent_data_ref_objectid(leaf, ref, owner); btrfs_set_extent_data_ref_offset(leaf, ref, offset); btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add); } else { num_refs = btrfs_extent_data_ref_count(leaf, ref); num_refs += refs_to_add; btrfs_set_extent_data_ref_count(leaf, ref, num_refs); } } btrfs_mark_buffer_dirty(leaf); ret = 0; fail: btrfs_release_path(path); return ret; } static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int refs_to_drop, int *last_ref) { struct btrfs_key key; struct btrfs_extent_data_ref *ref1 = NULL; struct btrfs_shared_data_ref *ref2 = NULL; struct extent_buffer *leaf; u32 num_refs = 0; int ret = 0; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { ref1 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_data_ref); num_refs = btrfs_extent_data_ref_count(leaf, ref1); } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) { ref2 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_shared_data_ref); num_refs = btrfs_shared_data_ref_count(leaf, ref2); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) { struct btrfs_extent_ref_v0 *ref0; ref0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref_v0); num_refs = btrfs_ref_count_v0(leaf, ref0); #endif } else { BUG(); } BUG_ON(num_refs < refs_to_drop); num_refs -= refs_to_drop; if (num_refs == 0) { ret = btrfs_del_item(trans, root, path); *last_ref = 1; } else { if (key.type == BTRFS_EXTENT_DATA_REF_KEY) btrfs_set_extent_data_ref_count(leaf, ref1, num_refs); else if (key.type == BTRFS_SHARED_DATA_REF_KEY) btrfs_set_shared_data_ref_count(leaf, ref2, num_refs); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 else { struct btrfs_extent_ref_v0 *ref0; ref0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref_v0); btrfs_set_ref_count_v0(leaf, ref0, num_refs); } #endif btrfs_mark_buffer_dirty(leaf); } return ret; } static noinline u32 extent_data_ref_count(struct btrfs_path *path, struct btrfs_extent_inline_ref *iref) { struct btrfs_key key; struct extent_buffer *leaf; struct btrfs_extent_data_ref *ref1; struct btrfs_shared_data_ref *ref2; u32 num_refs = 0; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (iref) { if (btrfs_extent_inline_ref_type(leaf, iref) == BTRFS_EXTENT_DATA_REF_KEY) { ref1 = (struct btrfs_extent_data_ref *)(&iref->offset); num_refs = btrfs_extent_data_ref_count(leaf, ref1); } else { ref2 = (struct btrfs_shared_data_ref *)(iref + 1); num_refs = btrfs_shared_data_ref_count(leaf, ref2); } } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { ref1 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_data_ref); num_refs = btrfs_extent_data_ref_count(leaf, ref1); } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) { ref2 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_shared_data_ref); num_refs = btrfs_shared_data_ref_count(leaf, ref2); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) { struct btrfs_extent_ref_v0 *ref0; ref0 = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref_v0); num_refs = btrfs_ref_count_v0(leaf, ref0); #endif } else { WARN_ON(1); } return num_refs; } static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 parent, u64 root_objectid) { struct btrfs_key key; int ret; key.objectid = bytenr; if (parent) { key.type = BTRFS_SHARED_BLOCK_REF_KEY; key.offset = parent; } else { key.type = BTRFS_TREE_BLOCK_REF_KEY; key.offset = root_objectid; } ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret > 0) ret = -ENOENT; #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 if (ret == -ENOENT && parent) { btrfs_release_path(path); key.type = BTRFS_EXTENT_REF_V0_KEY; ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret > 0) ret = -ENOENT; } #endif return ret; } static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 parent, u64 root_objectid) { struct btrfs_key key; int ret; key.objectid = bytenr; if (parent) { key.type = BTRFS_SHARED_BLOCK_REF_KEY; key.offset = parent; } else { key.type = BTRFS_TREE_BLOCK_REF_KEY; key.offset = root_objectid; } ret = btrfs_insert_empty_item(trans, root, path, &key, 0); btrfs_release_path(path); return ret; } static inline int extent_ref_type(u64 parent, u64 owner) { int type; if (owner < BTRFS_FIRST_FREE_OBJECTID) { if (parent > 0) type = BTRFS_SHARED_BLOCK_REF_KEY; else type = BTRFS_TREE_BLOCK_REF_KEY; } else { if (parent > 0) type = BTRFS_SHARED_DATA_REF_KEY; else type = BTRFS_EXTENT_DATA_REF_KEY; } return type; } static int find_next_key(struct btrfs_path *path, int level, struct btrfs_key *key) { for (; level < BTRFS_MAX_LEVEL; level++) { if (!path->nodes[level]) break; if (path->slots[level] + 1 >= btrfs_header_nritems(path->nodes[level])) continue; if (level == 0) btrfs_item_key_to_cpu(path->nodes[level], key, path->slots[level] + 1); else btrfs_node_key_to_cpu(path->nodes[level], key, path->slots[level] + 1); return 0; } return 1; } /* * look for inline back ref. if back ref is found, *ref_ret is set * to the address of inline back ref, and 0 is returned. * * if back ref isn't found, *ref_ret is set to the address where it * should be inserted, and -ENOENT is returned. * * if insert is true and there are too many inline back refs, the path * points to the extent item, and -EAGAIN is returned. * * NOTE: inline back refs are ordered in the same way that back ref * items in the tree are ordered. */ static noinline_for_stack int lookup_inline_extent_backref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_extent_inline_ref **ref_ret, u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid, u64 owner, u64 offset, int insert) { struct btrfs_key key; struct extent_buffer *leaf; struct btrfs_extent_item *ei; struct btrfs_extent_inline_ref *iref; u64 flags; u64 item_size; unsigned long ptr; unsigned long end; int extra_size; int type; int want; int ret; int err = 0; bool skinny_metadata = btrfs_fs_incompat(root->fs_info, SKINNY_METADATA); key.objectid = bytenr; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = num_bytes; want = extent_ref_type(parent, owner); if (insert) { extra_size = btrfs_extent_inline_ref_size(want); path->keep_locks = 1; } else extra_size = -1; /* * Owner is our parent level, so we can just add one to get the level * for the block we are interested in. */ if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) { key.type = BTRFS_METADATA_ITEM_KEY; key.offset = owner; } again: ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1); if (ret < 0) { err = ret; goto out; } /* * We may be a newly converted file system which still has the old fat * extent entries for metadata, so try and see if we have one of those. */ if (ret > 0 && skinny_metadata) { skinny_metadata = false; if (path->slots[0]) { path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid == bytenr && key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == num_bytes) ret = 0; } if (ret) { key.objectid = bytenr; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = num_bytes; btrfs_release_path(path); goto again; } } if (ret && !insert) { err = -ENOENT; goto out; } else if (WARN_ON(ret)) { err = -EIO; goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 if (item_size < sizeof(*ei)) { if (!insert) { err = -ENOENT; goto out; } ret = convert_extent_item_v0(trans, root, path, owner, extra_size); if (ret < 0) { err = ret; goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); } #endif BUG_ON(item_size < sizeof(*ei)); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); flags = btrfs_extent_flags(leaf, ei); ptr = (unsigned long)(ei + 1); end = (unsigned long)ei + item_size; if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) { ptr += sizeof(struct btrfs_tree_block_info); BUG_ON(ptr > end); } err = -ENOENT; while (1) { if (ptr >= end) { WARN_ON(ptr > end); break; } iref = (struct btrfs_extent_inline_ref *)ptr; type = btrfs_extent_inline_ref_type(leaf, iref); if (want < type) break; if (want > type) { ptr += btrfs_extent_inline_ref_size(type); continue; } if (type == BTRFS_EXTENT_DATA_REF_KEY) { struct btrfs_extent_data_ref *dref; dref = (struct btrfs_extent_data_ref *)(&iref->offset); if (match_extent_data_ref(leaf, dref, root_objectid, owner, offset)) { err = 0; break; } if (hash_extent_data_ref_item(leaf, dref) < hash_extent_data_ref(root_objectid, owner, offset)) break; } else { u64 ref_offset; ref_offset = btrfs_extent_inline_ref_offset(leaf, iref); if (parent > 0) { if (parent == ref_offset) { err = 0; break; } if (ref_offset < parent) break; } else { if (root_objectid == ref_offset) { err = 0; break; } if (ref_offset < root_objectid) break; } } ptr += btrfs_extent_inline_ref_size(type); } if (err == -ENOENT && insert) { if (item_size + extra_size >= BTRFS_MAX_EXTENT_ITEM_SIZE(root)) { err = -EAGAIN; goto out; } /* * To add new inline back ref, we have to make sure * there is no corresponding back ref item. * For simplicity, we just do not add new inline back * ref if there is any kind of item for this block */ if (find_next_key(path, 0, &key) == 0 && key.objectid == bytenr && key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) { err = -EAGAIN; goto out; } } *ref_ret = (struct btrfs_extent_inline_ref *)ptr; out: if (insert) { path->keep_locks = 0; btrfs_unlock_up_safe(path, 1); } return err; } /* * helper to add new inline back ref */ static noinline_for_stack void setup_inline_extent_backref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_extent_inline_ref *iref, u64 parent, u64 root_objectid, u64 owner, u64 offset, int refs_to_add, struct btrfs_delayed_extent_op *extent_op) { struct extent_buffer *leaf; struct btrfs_extent_item *ei; unsigned long ptr; unsigned long end; unsigned long item_offset; u64 refs; int size; int type; leaf = path->nodes[0]; ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); item_offset = (unsigned long)iref - (unsigned long)ei; type = extent_ref_type(parent, owner); size = btrfs_extent_inline_ref_size(type); btrfs_extend_item(root, path, size); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); refs = btrfs_extent_refs(leaf, ei); refs += refs_to_add; btrfs_set_extent_refs(leaf, ei, refs); if (extent_op) __run_delayed_extent_op(extent_op, leaf, ei); ptr = (unsigned long)ei + item_offset; end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]); if (ptr < end - size) memmove_extent_buffer(leaf, ptr + size, ptr, end - size - ptr); iref = (struct btrfs_extent_inline_ref *)ptr; btrfs_set_extent_inline_ref_type(leaf, iref, type); if (type == BTRFS_EXTENT_DATA_REF_KEY) { struct btrfs_extent_data_ref *dref; dref = (struct btrfs_extent_data_ref *)(&iref->offset); btrfs_set_extent_data_ref_root(leaf, dref, root_objectid); btrfs_set_extent_data_ref_objectid(leaf, dref, owner); btrfs_set_extent_data_ref_offset(leaf, dref, offset); btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add); } else if (type == BTRFS_SHARED_DATA_REF_KEY) { struct btrfs_shared_data_ref *sref; sref = (struct btrfs_shared_data_ref *)(iref + 1); btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add); btrfs_set_extent_inline_ref_offset(leaf, iref, parent); } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) { btrfs_set_extent_inline_ref_offset(leaf, iref, parent); } else { btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid); } btrfs_mark_buffer_dirty(leaf); } static int lookup_extent_backref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_extent_inline_ref **ref_ret, u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid, u64 owner, u64 offset) { int ret; ret = lookup_inline_extent_backref(trans, root, path, ref_ret, bytenr, num_bytes, parent, root_objectid, owner, offset, 0); if (ret != -ENOENT) return ret; btrfs_release_path(path); *ref_ret = NULL; if (owner < BTRFS_FIRST_FREE_OBJECTID) { ret = lookup_tree_block_ref(trans, root, path, bytenr, parent, root_objectid); } else { ret = lookup_extent_data_ref(trans, root, path, bytenr, parent, root_objectid, owner, offset); } return ret; } /* * helper to update/remove inline back ref */ static noinline_for_stack void update_inline_extent_backref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_extent_inline_ref *iref, int refs_to_mod, struct btrfs_delayed_extent_op *extent_op, int *last_ref) { struct extent_buffer *leaf; struct btrfs_extent_item *ei; struct btrfs_extent_data_ref *dref = NULL; struct btrfs_shared_data_ref *sref = NULL; unsigned long ptr; unsigned long end; u32 item_size; int size; int type; u64 refs; leaf = path->nodes[0]; ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); refs = btrfs_extent_refs(leaf, ei); WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0); refs += refs_to_mod; btrfs_set_extent_refs(leaf, ei, refs); if (extent_op) __run_delayed_extent_op(extent_op, leaf, ei); type = btrfs_extent_inline_ref_type(leaf, iref); if (type == BTRFS_EXTENT_DATA_REF_KEY) { dref = (struct btrfs_extent_data_ref *)(&iref->offset); refs = btrfs_extent_data_ref_count(leaf, dref); } else if (type == BTRFS_SHARED_DATA_REF_KEY) { sref = (struct btrfs_shared_data_ref *)(iref + 1); refs = btrfs_shared_data_ref_count(leaf, sref); } else { refs = 1; BUG_ON(refs_to_mod != -1); } BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod); refs += refs_to_mod; if (refs > 0) { if (type == BTRFS_EXTENT_DATA_REF_KEY) btrfs_set_extent_data_ref_count(leaf, dref, refs); else btrfs_set_shared_data_ref_count(leaf, sref, refs); } else { *last_ref = 1; size = btrfs_extent_inline_ref_size(type); item_size = btrfs_item_size_nr(leaf, path->slots[0]); ptr = (unsigned long)iref; end = (unsigned long)ei + item_size; if (ptr + size < end) memmove_extent_buffer(leaf, ptr, ptr + size, end - ptr - size); item_size -= size; btrfs_truncate_item(root, path, item_size, 1); } btrfs_mark_buffer_dirty(leaf); } static noinline_for_stack int insert_inline_extent_backref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid, u64 owner, u64 offset, int refs_to_add, struct btrfs_delayed_extent_op *extent_op) { struct btrfs_extent_inline_ref *iref; int ret; ret = lookup_inline_extent_backref(trans, root, path, &iref, bytenr, num_bytes, parent, root_objectid, owner, offset, 1); if (ret == 0) { BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID); update_inline_extent_backref(root, path, iref, refs_to_add, extent_op, NULL); } else if (ret == -ENOENT) { setup_inline_extent_backref(root, path, iref, parent, root_objectid, owner, offset, refs_to_add, extent_op); ret = 0; } return ret; } static int insert_extent_backref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 bytenr, u64 parent, u64 root_objectid, u64 owner, u64 offset, int refs_to_add) { int ret; if (owner < BTRFS_FIRST_FREE_OBJECTID) { BUG_ON(refs_to_add != 1); ret = insert_tree_block_ref(trans, root, path, bytenr, parent, root_objectid); } else { ret = insert_extent_data_ref(trans, root, path, bytenr, parent, root_objectid, owner, offset, refs_to_add); } return ret; } static int remove_extent_backref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_extent_inline_ref *iref, int refs_to_drop, int is_data, int *last_ref) { int ret = 0; BUG_ON(!is_data && refs_to_drop != 1); if (iref) { update_inline_extent_backref(root, path, iref, -refs_to_drop, NULL, last_ref); } else if (is_data) { ret = remove_extent_data_ref(trans, root, path, refs_to_drop, last_ref); } else { *last_ref = 1; ret = btrfs_del_item(trans, root, path); } return ret; } #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len)) static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len, u64 *discarded_bytes) { int j, ret = 0; u64 bytes_left, end; u64 aligned_start = ALIGN(start, 1 << 9); if (WARN_ON(start != aligned_start)) { len -= aligned_start - start; len = round_down(len, 1 << 9); start = aligned_start; } *discarded_bytes = 0; if (!len) return 0; end = start + len; bytes_left = len; /* Skip any superblocks on this device. */ for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) { u64 sb_start = btrfs_sb_offset(j); u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE; u64 size = sb_start - start; if (!in_range(sb_start, start, bytes_left) && !in_range(sb_end, start, bytes_left) && !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE)) continue; /* * Superblock spans beginning of range. Adjust start and * try again. */ if (sb_start <= start) { start += sb_end - start; if (start > end) { bytes_left = 0; break; } bytes_left = end - start; continue; } if (size) { ret = blkdev_issue_discard(bdev, start >> 9, size >> 9, GFP_NOFS, 0); if (!ret) *discarded_bytes += size; else if (ret != -EOPNOTSUPP) return ret; } start = sb_end; if (start > end) { bytes_left = 0; break; } bytes_left = end - start; } if (bytes_left) { ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9, GFP_NOFS, 0); if (!ret) *discarded_bytes += bytes_left; } return ret; } int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr, u64 num_bytes, u64 *actual_bytes) { int ret; u64 discarded_bytes = 0; struct btrfs_bio *bbio = NULL; /* Tell the block device(s) that the sectors can be discarded */ ret = btrfs_map_block(root->fs_info, REQ_DISCARD, bytenr, &num_bytes, &bbio, 0); /* Error condition is -ENOMEM */ if (!ret) { struct btrfs_bio_stripe *stripe = bbio->stripes; int i; for (i = 0; i < bbio->num_stripes; i++, stripe++) { u64 bytes; if (!stripe->dev->can_discard) continue; ret = btrfs_issue_discard(stripe->dev->bdev, stripe->physical, stripe->length, &bytes); if (!ret) discarded_bytes += bytes; else if (ret != -EOPNOTSUPP) break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */ /* * Just in case we get back EOPNOTSUPP for some reason, * just ignore the return value so we don't screw up * people calling discard_extent. */ ret = 0; } btrfs_put_bbio(bbio); } if (actual_bytes) *actual_bytes = discarded_bytes; if (ret == -EOPNOTSUPP) ret = 0; return ret; } /* Can return -ENOMEM */ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid, u64 owner, u64 offset, int no_quota) { int ret; struct btrfs_fs_info *fs_info = root->fs_info; BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID && root_objectid == BTRFS_TREE_LOG_OBJECTID); if (owner < BTRFS_FIRST_FREE_OBJECTID) { ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr, num_bytes, parent, root_objectid, (int)owner, BTRFS_ADD_DELAYED_REF, NULL, no_quota); } else { ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr, num_bytes, parent, root_objectid, owner, offset, BTRFS_ADD_DELAYED_REF, NULL, no_quota); } return ret; } static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, u64 parent, u64 root_objectid, u64 owner, u64 offset, int refs_to_add, struct btrfs_delayed_extent_op *extent_op) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_path *path; struct extent_buffer *leaf; struct btrfs_extent_item *item; struct btrfs_key key; u64 bytenr = node->bytenr; u64 num_bytes = node->num_bytes; u64 refs; int ret; int no_quota = node->no_quota; path = btrfs_alloc_path(); if (!path) return -ENOMEM; if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled) no_quota = 1; path->reada = 1; path->leave_spinning = 1; /* this will setup the path even if it fails to insert the back ref */ ret = insert_inline_extent_backref(trans, fs_info->extent_root, path, bytenr, num_bytes, parent, root_objectid, owner, offset, refs_to_add, extent_op); if ((ret < 0 && ret != -EAGAIN) || !ret) goto out; /* * Ok we had -EAGAIN which means we didn't have space to insert and * inline extent ref, so just update the reference count and add a * normal backref. */ leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); refs = btrfs_extent_refs(leaf, item); btrfs_set_extent_refs(leaf, item, refs + refs_to_add); if (extent_op) __run_delayed_extent_op(extent_op, leaf, item); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); path->reada = 1; path->leave_spinning = 1; /* now insert the actual backref */ ret = insert_extent_backref(trans, root->fs_info->extent_root, path, bytenr, parent, root_objectid, owner, offset, refs_to_add); if (ret) btrfs_abort_transaction(trans, root, ret); out: btrfs_free_path(path); return ret; } static int run_delayed_data_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, struct btrfs_delayed_extent_op *extent_op, int insert_reserved) { int ret = 0; struct btrfs_delayed_data_ref *ref; struct btrfs_key ins; u64 parent = 0; u64 ref_root = 0; u64 flags = 0; ins.objectid = node->bytenr; ins.offset = node->num_bytes; ins.type = BTRFS_EXTENT_ITEM_KEY; ref = btrfs_delayed_node_to_data_ref(node); trace_run_delayed_data_ref(node, ref, node->action); if (node->type == BTRFS_SHARED_DATA_REF_KEY) parent = ref->parent; ref_root = ref->root; if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) { if (extent_op) flags |= extent_op->flags_to_set; ret = alloc_reserved_file_extent(trans, root, parent, ref_root, flags, ref->objectid, ref->offset, &ins, node->ref_mod); } else if (node->action == BTRFS_ADD_DELAYED_REF) { ret = __btrfs_inc_extent_ref(trans, root, node, parent, ref_root, ref->objectid, ref->offset, node->ref_mod, extent_op); } else if (node->action == BTRFS_DROP_DELAYED_REF) { ret = __btrfs_free_extent(trans, root, node, parent, ref_root, ref->objectid, ref->offset, node->ref_mod, extent_op); } else { BUG(); } return ret; } static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op, struct extent_buffer *leaf, struct btrfs_extent_item *ei) { u64 flags = btrfs_extent_flags(leaf, ei); if (extent_op->update_flags) { flags |= extent_op->flags_to_set; btrfs_set_extent_flags(leaf, ei, flags); } if (extent_op->update_key) { struct btrfs_tree_block_info *bi; BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)); bi = (struct btrfs_tree_block_info *)(ei + 1); btrfs_set_tree_block_key(leaf, bi, &extent_op->key); } } static int run_delayed_extent_op(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, struct btrfs_delayed_extent_op *extent_op) { struct btrfs_key key; struct btrfs_path *path; struct btrfs_extent_item *ei; struct extent_buffer *leaf; u32 item_size; int ret; int err = 0; int metadata = !extent_op->is_data; if (trans->aborted) return 0; if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) metadata = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; key.objectid = node->bytenr; if (metadata) { key.type = BTRFS_METADATA_ITEM_KEY; key.offset = extent_op->level; } else { key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = node->num_bytes; } again: path->reada = 1; path->leave_spinning = 1; ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path, 0, 1); if (ret < 0) { err = ret; goto out; } if (ret > 0) { if (metadata) { if (path->slots[0] > 0) { path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid == node->bytenr && key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == node->num_bytes) ret = 0; } if (ret > 0) { btrfs_release_path(path); metadata = 0; key.objectid = node->bytenr; key.offset = node->num_bytes; key.type = BTRFS_EXTENT_ITEM_KEY; goto again; } } else { err = -EIO; goto out; } } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 if (item_size < sizeof(*ei)) { ret = convert_extent_item_v0(trans, root->fs_info->extent_root, path, (u64)-1, 0); if (ret < 0) { err = ret; goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); } #endif BUG_ON(item_size < sizeof(*ei)); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); __run_delayed_extent_op(extent_op, leaf, ei); btrfs_mark_buffer_dirty(leaf); out: btrfs_free_path(path); return err; } static int run_delayed_tree_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, struct btrfs_delayed_extent_op *extent_op, int insert_reserved) { int ret = 0; struct btrfs_delayed_tree_ref *ref; struct btrfs_key ins; u64 parent = 0; u64 ref_root = 0; bool skinny_metadata = btrfs_fs_incompat(root->fs_info, SKINNY_METADATA); ref = btrfs_delayed_node_to_tree_ref(node); trace_run_delayed_tree_ref(node, ref, node->action); if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) parent = ref->parent; ref_root = ref->root; ins.objectid = node->bytenr; if (skinny_metadata) { ins.offset = ref->level; ins.type = BTRFS_METADATA_ITEM_KEY; } else { ins.offset = node->num_bytes; ins.type = BTRFS_EXTENT_ITEM_KEY; } BUG_ON(node->ref_mod != 1); if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) { BUG_ON(!extent_op || !extent_op->update_flags); ret = alloc_reserved_tree_block(trans, root, parent, ref_root, extent_op->flags_to_set, &extent_op->key, ref->level, &ins, node->no_quota); } else if (node->action == BTRFS_ADD_DELAYED_REF) { ret = __btrfs_inc_extent_ref(trans, root, node, parent, ref_root, ref->level, 0, 1, extent_op); } else if (node->action == BTRFS_DROP_DELAYED_REF) { ret = __btrfs_free_extent(trans, root, node, parent, ref_root, ref->level, 0, 1, extent_op); } else { BUG(); } return ret; } /* helper function to actually process a single delayed ref entry */ static int run_one_delayed_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, struct btrfs_delayed_extent_op *extent_op, int insert_reserved) { int ret = 0; if (trans->aborted) { if (insert_reserved) btrfs_pin_extent(root, node->bytenr, node->num_bytes, 1); return 0; } if (btrfs_delayed_ref_is_head(node)) { struct btrfs_delayed_ref_head *head; /* * we've hit the end of the chain and we were supposed * to insert this extent into the tree. But, it got * deleted before we ever needed to insert it, so all * we have to do is clean up the accounting */ BUG_ON(extent_op); head = btrfs_delayed_node_to_head(node); trace_run_delayed_ref_head(node, head, node->action); if (insert_reserved) { btrfs_pin_extent(root, node->bytenr, node->num_bytes, 1); if (head->is_data) { ret = btrfs_del_csums(trans, root, node->bytenr, node->num_bytes); } } return ret; } if (node->type == BTRFS_TREE_BLOCK_REF_KEY || node->type == BTRFS_SHARED_BLOCK_REF_KEY) ret = run_delayed_tree_ref(trans, root, node, extent_op, insert_reserved); else if (node->type == BTRFS_EXTENT_DATA_REF_KEY || node->type == BTRFS_SHARED_DATA_REF_KEY) ret = run_delayed_data_ref(trans, root, node, extent_op, insert_reserved); else BUG(); return ret; } static inline struct btrfs_delayed_ref_node * select_delayed_ref(struct btrfs_delayed_ref_head *head) { struct btrfs_delayed_ref_node *ref; if (list_empty(&head->ref_list)) return NULL; /* * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first. * This is to prevent a ref count from going down to zero, which deletes * the extent item from the extent tree, when there still are references * to add, which would fail because they would not find the extent item. */ list_for_each_entry(ref, &head->ref_list, list) { if (ref->action == BTRFS_ADD_DELAYED_REF) return ref; } return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node, list); } /* * Returns 0 on success or if called with an already aborted transaction. * Returns -ENOMEM or -EIO on failure and will abort the transaction. */ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, struct btrfs_root *root, unsigned long nr) { struct btrfs_delayed_ref_root *delayed_refs; struct btrfs_delayed_ref_node *ref; struct btrfs_delayed_ref_head *locked_ref = NULL; struct btrfs_delayed_extent_op *extent_op; struct btrfs_fs_info *fs_info = root->fs_info; ktime_t start = ktime_get(); int ret; unsigned long count = 0; unsigned long actual_count = 0; int must_insert_reserved = 0; delayed_refs = &trans->transaction->delayed_refs; while (1) { if (!locked_ref) { if (count >= nr) break; spin_lock(&delayed_refs->lock); locked_ref = btrfs_select_ref_head(trans); if (!locked_ref) { spin_unlock(&delayed_refs->lock); break; } /* grab the lock that says we are going to process * all the refs for this head */ ret = btrfs_delayed_ref_lock(trans, locked_ref); spin_unlock(&delayed_refs->lock); /* * we may have dropped the spin lock to get the head * mutex lock, and that might have given someone else * time to free the head. If that's true, it has been * removed from our list and we can move on. */ if (ret == -EAGAIN) { locked_ref = NULL; count++; continue; } } spin_lock(&locked_ref->lock); /* * locked_ref is the head node, so we have to go one * node back for any delayed ref updates */ ref = select_delayed_ref(locked_ref); if (ref && ref->seq && btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) { spin_unlock(&locked_ref->lock); btrfs_delayed_ref_unlock(locked_ref); spin_lock(&delayed_refs->lock); locked_ref->processing = 0; delayed_refs->num_heads_ready++; spin_unlock(&delayed_refs->lock); locked_ref = NULL; cond_resched(); count++; continue; } /* * record the must insert reserved flag before we * drop the spin lock. */ must_insert_reserved = locked_ref->must_insert_reserved; locked_ref->must_insert_reserved = 0; extent_op = locked_ref->extent_op; locked_ref->extent_op = NULL; if (!ref) { /* All delayed refs have been processed, Go ahead * and send the head node to run_one_delayed_ref, * so that any accounting fixes can happen */ ref = &locked_ref->node; if (extent_op && must_insert_reserved) { btrfs_free_delayed_extent_op(extent_op); extent_op = NULL; } if (extent_op) { spin_unlock(&locked_ref->lock); ret = run_delayed_extent_op(trans, root, ref, extent_op); btrfs_free_delayed_extent_op(extent_op); if (ret) { /* * Need to reset must_insert_reserved if * there was an error so the abort stuff * can cleanup the reserved space * properly. */ if (must_insert_reserved) locked_ref->must_insert_reserved = 1; locked_ref->processing = 0; btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret); btrfs_delayed_ref_unlock(locked_ref); return ret; } continue; } /* * Need to drop our head ref lock and re-aqcuire the * delayed ref lock and then re-check to make sure * nobody got added. */ spin_unlock(&locked_ref->lock); spin_lock(&delayed_refs->lock); spin_lock(&locked_ref->lock); if (!list_empty(&locked_ref->ref_list) || locked_ref->extent_op) { spin_unlock(&locked_ref->lock); spin_unlock(&delayed_refs->lock); continue; } ref->in_tree = 0; delayed_refs->num_heads--; rb_erase(&locked_ref->href_node, &delayed_refs->href_root); spin_unlock(&delayed_refs->lock); } else { actual_count++; ref->in_tree = 0; list_del(&ref->list); } atomic_dec(&delayed_refs->num_entries); if (!btrfs_delayed_ref_is_head(ref)) { /* * when we play the delayed ref, also correct the * ref_mod on head */ switch (ref->action) { case BTRFS_ADD_DELAYED_REF: case BTRFS_ADD_DELAYED_EXTENT: locked_ref->node.ref_mod -= ref->ref_mod; break; case BTRFS_DROP_DELAYED_REF: locked_ref->node.ref_mod += ref->ref_mod; break; default: WARN_ON(1); } } spin_unlock(&locked_ref->lock); ret = run_one_delayed_ref(trans, root, ref, extent_op, must_insert_reserved); btrfs_free_delayed_extent_op(extent_op); if (ret) { locked_ref->processing = 0; btrfs_delayed_ref_unlock(locked_ref); btrfs_put_delayed_ref(ref); btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret); return ret; } /* * If this node is a head, that means all the refs in this head * have been dealt with, and we will pick the next head to deal * with, so we must unlock the head and drop it from the cluster * list before we release it. */ if (btrfs_delayed_ref_is_head(ref)) { if (locked_ref->is_data && locked_ref->total_ref_mod < 0) { spin_lock(&delayed_refs->lock); delayed_refs->pending_csums -= ref->num_bytes; spin_unlock(&delayed_refs->lock); } btrfs_delayed_ref_unlock(locked_ref); locked_ref = NULL; } btrfs_put_delayed_ref(ref); count++; cond_resched(); } /* * We don't want to include ref heads since we can have empty ref heads * and those will drastically skew our runtime down since we just do * accounting, no actual extent tree updates. */ if (actual_count > 0) { u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start)); u64 avg; /* * We weigh the current average higher than our current runtime * to avoid large swings in the average. */ spin_lock(&delayed_refs->lock); avg = fs_info->avg_delayed_ref_runtime * 3 + runtime; fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */ spin_unlock(&delayed_refs->lock); } return 0; } #ifdef SCRAMBLE_DELAYED_REFS /* * Normally delayed refs get processed in ascending bytenr order. This * correlates in most cases to the order added. To expose dependencies on this * order, we start to process the tree in the middle instead of the beginning */ static u64 find_middle(struct rb_root *root) { struct rb_node *n = root->rb_node; struct btrfs_delayed_ref_node *entry; int alt = 1; u64 middle; u64 first = 0, last = 0; n = rb_first(root); if (n) { entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); first = entry->bytenr; } n = rb_last(root); if (n) { entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); last = entry->bytenr; } n = root->rb_node; while (n) { entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); WARN_ON(!entry->in_tree); middle = entry->bytenr; if (alt) n = n->rb_left; else n = n->rb_right; alt = 1 - alt; } return middle; } #endif static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads) { u64 num_bytes; num_bytes = heads * (sizeof(struct btrfs_extent_item) + sizeof(struct btrfs_extent_inline_ref)); if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) num_bytes += heads * sizeof(struct btrfs_tree_block_info); /* * We don't ever fill up leaves all the way so multiply by 2 just to be * closer to what we're really going to want to ouse. */ return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root)); } /* * Takes the number of bytes to be csumm'ed and figures out how many leaves it * would require to store the csums for that many bytes. */ u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes) { u64 csum_size; u64 num_csums_per_leaf; u64 num_csums; csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item); num_csums_per_leaf = div64_u64(csum_size, (u64)btrfs_super_csum_size(root->fs_info->super_copy)); num_csums = div64_u64(csum_bytes, root->sectorsize); num_csums += num_csums_per_leaf - 1; num_csums = div64_u64(num_csums, num_csums_per_leaf); return num_csums; } int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_block_rsv *global_rsv; u64 num_heads = trans->transaction->delayed_refs.num_heads_ready; u64 csum_bytes = trans->transaction->delayed_refs.pending_csums; u64 num_dirty_bgs = trans->transaction->num_dirty_bgs; u64 num_bytes, num_dirty_bgs_bytes; int ret = 0; num_bytes = btrfs_calc_trans_metadata_size(root, 1); num_heads = heads_to_leaves(root, num_heads); if (num_heads > 1) num_bytes += (num_heads - 1) * root->nodesize; num_bytes <<= 1; num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize; num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root, num_dirty_bgs); global_rsv = &root->fs_info->global_block_rsv; /* * If we can't allocate any more chunks lets make sure we have _lots_ of * wiggle room since running delayed refs can create more delayed refs. */ if (global_rsv->space_info->full) { num_dirty_bgs_bytes <<= 1; num_bytes <<= 1; } spin_lock(&global_rsv->lock); if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes) ret = 1; spin_unlock(&global_rsv->lock); return ret; } int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; u64 num_entries = atomic_read(&trans->transaction->delayed_refs.num_entries); u64 avg_runtime; u64 val; smp_mb(); avg_runtime = fs_info->avg_delayed_ref_runtime; val = num_entries * avg_runtime; if (num_entries * avg_runtime >= NSEC_PER_SEC) return 1; if (val >= NSEC_PER_SEC / 2) return 2; return btrfs_check_space_for_delayed_refs(trans, root); } struct async_delayed_refs { struct btrfs_root *root; int count; int error; int sync; struct completion wait; struct btrfs_work work; }; static void delayed_ref_async_start(struct btrfs_work *work) { struct async_delayed_refs *async; struct btrfs_trans_handle *trans; int ret; async = container_of(work, struct async_delayed_refs, work); trans = btrfs_join_transaction(async->root); if (IS_ERR(trans)) { async->error = PTR_ERR(trans); goto done; } /* * trans->sync means that when we call end_transaciton, we won't * wait on delayed refs */ trans->sync = true; ret = btrfs_run_delayed_refs(trans, async->root, async->count); if (ret) async->error = ret; ret = btrfs_end_transaction(trans, async->root); if (ret && !async->error) async->error = ret; done: if (async->sync) complete(&async->wait); else kfree(async); } int btrfs_async_run_delayed_refs(struct btrfs_root *root, unsigned long count, int wait) { struct async_delayed_refs *async; int ret; async = kmalloc(sizeof(*async), GFP_NOFS); if (!async) return -ENOMEM; async->root = root->fs_info->tree_root; async->count = count; async->error = 0; if (wait) async->sync = 1; else async->sync = 0; init_completion(&async->wait); btrfs_init_work(&async->work, btrfs_extent_refs_helper, delayed_ref_async_start, NULL, NULL); btrfs_queue_work(root->fs_info->extent_workers, &async->work); if (wait) { wait_for_completion(&async->wait); ret = async->error; kfree(async); return ret; } return 0; } /* * this starts processing the delayed reference count updates and * extent insertions we have queued up so far. count can be * 0, which means to process everything in the tree at the start * of the run (but not newly added entries), or it can be some target * number you'd like to process. * * Returns 0 on success or if called with an aborted transaction * Returns <0 on error and aborts the transaction */ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, struct btrfs_root *root, unsigned long count) { struct rb_node *node; struct btrfs_delayed_ref_root *delayed_refs; struct btrfs_delayed_ref_head *head; int ret; int run_all = count == (unsigned long)-1; bool can_flush_pending_bgs = trans->can_flush_pending_bgs; /* We'll clean this up in btrfs_cleanup_transaction */ if (trans->aborted) return 0; if (root == root->fs_info->extent_root) root = root->fs_info->tree_root; delayed_refs = &trans->transaction->delayed_refs; if (count == 0) count = atomic_read(&delayed_refs->num_entries) * 2; again: #ifdef SCRAMBLE_DELAYED_REFS delayed_refs->run_delayed_start = find_middle(&delayed_refs->root); #endif trans->can_flush_pending_bgs = false; ret = __btrfs_run_delayed_refs(trans, root, count); if (ret < 0) { btrfs_abort_transaction(trans, root, ret); return ret; } if (run_all) { if (!list_empty(&trans->new_bgs)) btrfs_create_pending_block_groups(trans, root); spin_lock(&delayed_refs->lock); node = rb_first(&delayed_refs->href_root); if (!node) { spin_unlock(&delayed_refs->lock); goto out; } count = (unsigned long)-1; while (node) { head = rb_entry(node, struct btrfs_delayed_ref_head, href_node); if (btrfs_delayed_ref_is_head(&head->node)) { struct btrfs_delayed_ref_node *ref; ref = &head->node; atomic_inc(&ref->refs); spin_unlock(&delayed_refs->lock); /* * Mutex was contended, block until it's * released and try again */ mutex_lock(&head->mutex); mutex_unlock(&head->mutex); btrfs_put_delayed_ref(ref); cond_resched(); goto again; } else { WARN_ON(1); } node = rb_next(node); } spin_unlock(&delayed_refs->lock); cond_resched(); goto again; } out: assert_qgroups_uptodate(trans); trans->can_flush_pending_bgs = can_flush_pending_bgs; return 0; } int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, u64 flags, int level, int is_data) { struct btrfs_delayed_extent_op *extent_op; int ret; extent_op = btrfs_alloc_delayed_extent_op(); if (!extent_op) return -ENOMEM; extent_op->flags_to_set = flags; extent_op->update_flags = 1; extent_op->update_key = 0; extent_op->is_data = is_data ? 1 : 0; extent_op->level = level; ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr, num_bytes, extent_op); if (ret) btrfs_free_delayed_extent_op(extent_op); return ret; } static noinline int check_delayed_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 objectid, u64 offset, u64 bytenr) { struct btrfs_delayed_ref_head *head; struct btrfs_delayed_ref_node *ref; struct btrfs_delayed_data_ref *data_ref; struct btrfs_delayed_ref_root *delayed_refs; int ret = 0; delayed_refs = &trans->transaction->delayed_refs; spin_lock(&delayed_refs->lock); head = btrfs_find_delayed_ref_head(trans, bytenr); if (!head) { spin_unlock(&delayed_refs->lock); return 0; } if (!mutex_trylock(&head->mutex)) { atomic_inc(&head->node.refs); spin_unlock(&delayed_refs->lock); btrfs_release_path(path); /* * Mutex was contended, block until it's released and let * caller try again */ mutex_lock(&head->mutex); mutex_unlock(&head->mutex); btrfs_put_delayed_ref(&head->node); return -EAGAIN; } spin_unlock(&delayed_refs->lock); spin_lock(&head->lock); list_for_each_entry(ref, &head->ref_list, list) { /* If it's a shared ref we know a cross reference exists */ if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) { ret = 1; break; } data_ref = btrfs_delayed_node_to_data_ref(ref); /* * If our ref doesn't match the one we're currently looking at * then we have a cross reference. */ if (data_ref->root != root->root_key.objectid || data_ref->objectid != objectid || data_ref->offset != offset) { ret = 1; break; } } spin_unlock(&head->lock); mutex_unlock(&head->mutex); return ret; } static noinline int check_committed_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u64 objectid, u64 offset, u64 bytenr) { struct btrfs_root *extent_root = root->fs_info->extent_root; struct extent_buffer *leaf; struct btrfs_extent_data_ref *ref; struct btrfs_extent_inline_ref *iref; struct btrfs_extent_item *ei; struct btrfs_key key; u32 item_size; int ret; key.objectid = bytenr; key.offset = (u64)-1; key.type = BTRFS_EXTENT_ITEM_KEY; ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); if (ret < 0) goto out; BUG_ON(ret == 0); /* Corruption */ ret = -ENOENT; if (path->slots[0] == 0) goto out; path->slots[0]--; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY) goto out; ret = 1; item_size = btrfs_item_size_nr(leaf, path->slots[0]); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 if (item_size < sizeof(*ei)) { WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0)); goto out; } #endif ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); if (item_size != sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY)) goto out; if (btrfs_extent_generation(leaf, ei) <= btrfs_root_last_snapshot(&root->root_item)) goto out; iref = (struct btrfs_extent_inline_ref *)(ei + 1); if (btrfs_extent_inline_ref_type(leaf, iref) != BTRFS_EXTENT_DATA_REF_KEY) goto out; ref = (struct btrfs_extent_data_ref *)(&iref->offset); if (btrfs_extent_refs(leaf, ei) != btrfs_extent_data_ref_count(leaf, ref) || btrfs_extent_data_ref_root(leaf, ref) != root->root_key.objectid || btrfs_extent_data_ref_objectid(leaf, ref) != objectid || btrfs_extent_data_ref_offset(leaf, ref) != offset) goto out; ret = 0; out: return ret; } int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid, u64 offset, u64 bytenr) { struct btrfs_path *path; int ret; int ret2; path = btrfs_alloc_path(); if (!path) return -ENOENT; do { ret = check_committed_ref(trans, root, path, objectid, offset, bytenr); if (ret && ret != -ENOENT) goto out; ret2 = check_delayed_ref(trans, root, path, objectid, offset, bytenr); } while (ret2 == -EAGAIN); if (ret2 && ret2 != -ENOENT) { ret = ret2; goto out; } if (ret != -ENOENT || ret2 != -ENOENT) ret = 0; out: btrfs_free_path(path); if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID) WARN_ON(ret > 0); return ret; } static int __btrfs_mod_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, int full_backref, int inc) { u64 bytenr; u64 num_bytes; u64 parent; u64 ref_root; u32 nritems; struct btrfs_key key; struct btrfs_file_extent_item *fi; int i; int level; int ret = 0; int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *, u64, u64, u64, u64, u64, u64, int); if (btrfs_test_is_dummy_root(root)) return 0; ref_root = btrfs_header_owner(buf); nritems = btrfs_header_nritems(buf); level = btrfs_header_level(buf); if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0) return 0; if (inc) process_func = btrfs_inc_extent_ref; else process_func = btrfs_free_extent; if (full_backref) parent = buf->start; else parent = 0; for (i = 0; i < nritems; i++) { if (level == 0) { btrfs_item_key_to_cpu(buf, &key, i); if (key.type != BTRFS_EXTENT_DATA_KEY) continue; fi = btrfs_item_ptr(buf, i, struct btrfs_file_extent_item); if (btrfs_file_extent_type(buf, fi) == BTRFS_FILE_EXTENT_INLINE) continue; bytenr = btrfs_file_extent_disk_bytenr(buf, fi); if (bytenr == 0) continue; num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi); key.offset -= btrfs_file_extent_offset(buf, fi); ret = process_func(trans, root, bytenr, num_bytes, parent, ref_root, key.objectid, key.offset, 1); if (ret) goto fail; } else { bytenr = btrfs_node_blockptr(buf, i); num_bytes = root->nodesize; ret = process_func(trans, root, bytenr, num_bytes, parent, ref_root, level - 1, 0, 1); if (ret) goto fail; } } return 0; fail: return ret; } int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, int full_backref) { return __btrfs_mod_ref(trans, root, buf, full_backref, 1); } int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, int full_backref) { return __btrfs_mod_ref(trans, root, buf, full_backref, 0); } static int write_one_cache_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_block_group_cache *cache) { int ret; struct btrfs_root *extent_root = root->fs_info->extent_root; unsigned long bi; struct extent_buffer *leaf; ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1); if (ret) { if (ret > 0) ret = -ENOENT; goto fail; } leaf = path->nodes[0]; bi = btrfs_item_ptr_offset(leaf, path->slots[0]); write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item)); btrfs_mark_buffer_dirty(leaf); fail: btrfs_release_path(path); return ret; } static struct btrfs_block_group_cache * next_block_group(struct btrfs_root *root, struct btrfs_block_group_cache *cache) { struct rb_node *node; spin_lock(&root->fs_info->block_group_cache_lock); /* If our block group was removed, we need a full search. */ if (RB_EMPTY_NODE(&cache->cache_node)) { const u64 next_bytenr = cache->key.objectid + cache->key.offset; spin_unlock(&root->fs_info->block_group_cache_lock); btrfs_put_block_group(cache); cache = btrfs_lookup_first_block_group(root->fs_info, next_bytenr); return cache; } node = rb_next(&cache->cache_node); btrfs_put_block_group(cache); if (node) { cache = rb_entry(node, struct btrfs_block_group_cache, cache_node); btrfs_get_block_group(cache); } else cache = NULL; spin_unlock(&root->fs_info->block_group_cache_lock); return cache; } static int cache_save_setup(struct btrfs_block_group_cache *block_group, struct btrfs_trans_handle *trans, struct btrfs_path *path) { struct btrfs_root *root = block_group->fs_info->tree_root; struct inode *inode = NULL; u64 alloc_hint = 0; int dcs = BTRFS_DC_ERROR; u64 num_pages = 0; int retries = 0; int ret = 0; /* * If this block group is smaller than 100 megs don't bother caching the * block group. */ if (block_group->key.offset < (100 * 1024 * 1024)) { spin_lock(&block_group->lock); block_group->disk_cache_state = BTRFS_DC_WRITTEN; spin_unlock(&block_group->lock); return 0; } if (trans->aborted) return 0; again: inode = lookup_free_space_inode(root, block_group, path); if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) { ret = PTR_ERR(inode); btrfs_release_path(path); goto out; } if (IS_ERR(inode)) { BUG_ON(retries); retries++; if (block_group->ro) goto out_free; ret = create_free_space_inode(root, trans, block_group, path); if (ret) goto out_free; goto again; } /* We've already setup this transaction, go ahead and exit */ if (block_group->cache_generation == trans->transid && i_size_read(inode)) { dcs = BTRFS_DC_SETUP; goto out_put; } /* * We want to set the generation to 0, that way if anything goes wrong * from here on out we know not to trust this cache when we load up next * time. */ BTRFS_I(inode)->generation = 0; ret = btrfs_update_inode(trans, root, inode); if (ret) { /* * So theoretically we could recover from this, simply set the * super cache generation to 0 so we know to invalidate the * cache, but then we'd have to keep track of the block groups * that fail this way so we know we _have_ to reset this cache * before the next commit or risk reading stale cache. So to * limit our exposure to horrible edge cases lets just abort the * transaction, this only happens in really bad situations * anyway. */ btrfs_abort_transaction(trans, root, ret); goto out_put; } WARN_ON(ret); if (i_size_read(inode) > 0) { ret = btrfs_check_trunc_cache_free_space(root, &root->fs_info->global_block_rsv); if (ret) goto out_put; ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode); if (ret) goto out_put; } spin_lock(&block_group->lock); if (block_group->cached != BTRFS_CACHE_FINISHED || !btrfs_test_opt(root, SPACE_CACHE)) { /* * don't bother trying to write stuff out _if_ * a) we're not cached, * b) we're with nospace_cache mount option. */ dcs = BTRFS_DC_WRITTEN; spin_unlock(&block_group->lock); goto out_put; } spin_unlock(&block_group->lock); /* * We hit an ENOSPC when setting up the cache in this transaction, just * skip doing the setup, we've already cleared the cache so we're safe. */ if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) { ret = -ENOSPC; goto out_put; } /* * Try to preallocate enough space based on how big the block group is. * Keep in mind this has to include any pinned space which could end up * taking up quite a bit since it's not folded into the other space * cache. */ num_pages = div_u64(block_group->key.offset, 256 * 1024 * 1024); if (!num_pages) num_pages = 1; num_pages *= 16; num_pages *= PAGE_CACHE_SIZE; ret = btrfs_check_data_free_space(inode, num_pages, num_pages); if (ret) goto out_put; ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages, num_pages, num_pages, &alloc_hint); /* * Our cache requires contiguous chunks so that we don't modify a bunch * of metadata or split extents when writing the cache out, which means * we can enospc if we are heavily fragmented in addition to just normal * out of space conditions. So if we hit this just skip setting up any * other block groups for this transaction, maybe we'll unpin enough * space the next time around. */ if (!ret) dcs = BTRFS_DC_SETUP; else if (ret == -ENOSPC) set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags); btrfs_free_reserved_data_space(inode, num_pages); out_put: iput(inode); out_free: btrfs_release_path(path); out: spin_lock(&block_group->lock); if (!ret && dcs == BTRFS_DC_SETUP) block_group->cache_generation = trans->transid; block_group->disk_cache_state = dcs; spin_unlock(&block_group->lock); return ret; } int btrfs_setup_space_cache(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_block_group_cache *cache, *tmp; struct btrfs_transaction *cur_trans = trans->transaction; struct btrfs_path *path; if (list_empty(&cur_trans->dirty_bgs) || !btrfs_test_opt(root, SPACE_CACHE)) return 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* Could add new block groups, use _safe just in case */ list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs, dirty_list) { if (cache->disk_cache_state == BTRFS_DC_CLEAR) cache_save_setup(cache, trans, path); } btrfs_free_path(path); return 0; } /* * transaction commit does final block group cache writeback during a * critical section where nothing is allowed to change the FS. This is * required in order for the cache to actually match the block group, * but can introduce a lot of latency into the commit. * * So, btrfs_start_dirty_block_groups is here to kick off block group * cache IO. There's a chance we'll have to redo some of it if the * block group changes again during the commit, but it greatly reduces * the commit latency by getting rid of the easy block groups while * we're still allowing others to join the commit. */ int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_block_group_cache *cache; struct btrfs_transaction *cur_trans = trans->transaction; int ret = 0; int should_put; struct btrfs_path *path = NULL; LIST_HEAD(dirty); struct list_head *io = &cur_trans->io_bgs; int num_started = 0; int loops = 0; spin_lock(&cur_trans->dirty_bgs_lock); if (list_empty(&cur_trans->dirty_bgs)) { spin_unlock(&cur_trans->dirty_bgs_lock); return 0; } list_splice_init(&cur_trans->dirty_bgs, &dirty); spin_unlock(&cur_trans->dirty_bgs_lock); again: /* * make sure all the block groups on our dirty list actually * exist */ btrfs_create_pending_block_groups(trans, root); if (!path) { path = btrfs_alloc_path(); if (!path) return -ENOMEM; } /* * cache_write_mutex is here only to save us from balance or automatic * removal of empty block groups deleting this block group while we are * writing out the cache */ mutex_lock(&trans->transaction->cache_write_mutex); while (!list_empty(&dirty)) { cache = list_first_entry(&dirty, struct btrfs_block_group_cache, dirty_list); /* * this can happen if something re-dirties a block * group that is already under IO. Just wait for it to * finish and then do it all again */ if (!list_empty(&cache->io_list)) { list_del_init(&cache->io_list); btrfs_wait_cache_io(root, trans, cache, &cache->io_ctl, path, cache->key.objectid); btrfs_put_block_group(cache); } /* * btrfs_wait_cache_io uses the cache->dirty_list to decide * if it should update the cache_state. Don't delete * until after we wait. * * Since we're not running in the commit critical section * we need the dirty_bgs_lock to protect from update_block_group */ spin_lock(&cur_trans->dirty_bgs_lock); list_del_init(&cache->dirty_list); spin_unlock(&cur_trans->dirty_bgs_lock); should_put = 1; cache_save_setup(cache, trans, path); if (cache->disk_cache_state == BTRFS_DC_SETUP) { cache->io_ctl.inode = NULL; ret = btrfs_write_out_cache(root, trans, cache, path); if (ret == 0 && cache->io_ctl.inode) { num_started++; should_put = 0; /* * the cache_write_mutex is protecting * the io_list */ list_add_tail(&cache->io_list, io); } else { /* * if we failed to write the cache, the * generation will be bad and life goes on */ ret = 0; } } if (!ret) { ret = write_one_cache_group(trans, root, path, cache); /* * Our block group might still be attached to the list * of new block groups in the transaction handle of some * other task (struct btrfs_trans_handle->new_bgs). This * means its block group item isn't yet in the extent * tree. If this happens ignore the error, as we will * try again later in the critical section of the * transaction commit. */ if (ret == -ENOENT) { ret = 0; spin_lock(&cur_trans->dirty_bgs_lock); if (list_empty(&cache->dirty_list)) { list_add_tail(&cache->dirty_list, &cur_trans->dirty_bgs); btrfs_get_block_group(cache); } spin_unlock(&cur_trans->dirty_bgs_lock); } else if (ret) { btrfs_abort_transaction(trans, root, ret); } } /* if its not on the io list, we need to put the block group */ if (should_put) btrfs_put_block_group(cache); if (ret) break; /* * Avoid blocking other tasks for too long. It might even save * us from writing caches for block groups that are going to be * removed. */ mutex_unlock(&trans->transaction->cache_write_mutex); mutex_lock(&trans->transaction->cache_write_mutex); } mutex_unlock(&trans->transaction->cache_write_mutex); /* * go through delayed refs for all the stuff we've just kicked off * and then loop back (just once) */ ret = btrfs_run_delayed_refs(trans, root, 0); if (!ret && loops == 0) { loops++; spin_lock(&cur_trans->dirty_bgs_lock); list_splice_init(&cur_trans->dirty_bgs, &dirty); /* * dirty_bgs_lock protects us from concurrent block group * deletes too (not just cache_write_mutex). */ if (!list_empty(&dirty)) { spin_unlock(&cur_trans->dirty_bgs_lock); goto again; } spin_unlock(&cur_trans->dirty_bgs_lock); } btrfs_free_path(path); return ret; } int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_block_group_cache *cache; struct btrfs_transaction *cur_trans = trans->transaction; int ret = 0; int should_put; struct btrfs_path *path; struct list_head *io = &cur_trans->io_bgs; int num_started = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* * We don't need the lock here since we are protected by the transaction * commit. We want to do the cache_save_setup first and then run the * delayed refs to make sure we have the best chance at doing this all * in one shot. */ while (!list_empty(&cur_trans->dirty_bgs)) { cache = list_first_entry(&cur_trans->dirty_bgs, struct btrfs_block_group_cache, dirty_list); /* * this can happen if cache_save_setup re-dirties a block * group that is already under IO. Just wait for it to * finish and then do it all again */ if (!list_empty(&cache->io_list)) { list_del_init(&cache->io_list); btrfs_wait_cache_io(root, trans, cache, &cache->io_ctl, path, cache->key.objectid); btrfs_put_block_group(cache); } /* * don't remove from the dirty list until after we've waited * on any pending IO */ list_del_init(&cache->dirty_list); should_put = 1; cache_save_setup(cache, trans, path); if (!ret) ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1); if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) { cache->io_ctl.inode = NULL; ret = btrfs_write_out_cache(root, trans, cache, path); if (ret == 0 && cache->io_ctl.inode) { num_started++; should_put = 0; list_add_tail(&cache->io_list, io); } else { /* * if we failed to write the cache, the * generation will be bad and life goes on */ ret = 0; } } if (!ret) { ret = write_one_cache_group(trans, root, path, cache); if (ret) btrfs_abort_transaction(trans, root, ret); } /* if its not on the io list, we need to put the block group */ if (should_put) btrfs_put_block_group(cache); } while (!list_empty(io)) { cache = list_first_entry(io, struct btrfs_block_group_cache, io_list); list_del_init(&cache->io_list); btrfs_wait_cache_io(root, trans, cache, &cache->io_ctl, path, cache->key.objectid); btrfs_put_block_group(cache); } btrfs_free_path(path); return ret; } int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr) { struct btrfs_block_group_cache *block_group; int readonly = 0; block_group = btrfs_lookup_block_group(root->fs_info, bytenr); if (!block_group || block_group->ro) readonly = 1; if (block_group) btrfs_put_block_group(block_group); return readonly; } static const char *alloc_name(u64 flags) { switch (flags) { case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA: return "mixed"; case BTRFS_BLOCK_GROUP_METADATA: return "metadata"; case BTRFS_BLOCK_GROUP_DATA: return "data"; case BTRFS_BLOCK_GROUP_SYSTEM: return "system"; default: WARN_ON(1); return "invalid-combination"; }; } static int update_space_info(struct btrfs_fs_info *info, u64 flags, u64 total_bytes, u64 bytes_used, struct btrfs_space_info **space_info) { struct btrfs_space_info *found; int i; int factor; int ret; if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) factor = 2; else factor = 1; found = __find_space_info(info, flags); if (found) { spin_lock(&found->lock); found->total_bytes += total_bytes; found->disk_total += total_bytes * factor; found->bytes_used += bytes_used; found->disk_used += bytes_used * factor; if (total_bytes > 0) found->full = 0; spin_unlock(&found->lock); *space_info = found; return 0; } found = kzalloc(sizeof(*found), GFP_NOFS); if (!found) return -ENOMEM; ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL); if (ret) { kfree(found); return ret; } for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) INIT_LIST_HEAD(&found->block_groups[i]); init_rwsem(&found->groups_sem); spin_lock_init(&found->lock); found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK; found->total_bytes = total_bytes; found->disk_total = total_bytes * factor; found->bytes_used = bytes_used; found->disk_used = bytes_used * factor; found->bytes_pinned = 0; found->bytes_reserved = 0; found->bytes_readonly = 0; found->bytes_may_use = 0; found->full = 0; found->max_extent_size = 0; found->force_alloc = CHUNK_ALLOC_NO_FORCE; found->chunk_alloc = 0; found->flush = 0; init_waitqueue_head(&found->wait); INIT_LIST_HEAD(&found->ro_bgs); ret = kobject_init_and_add(&found->kobj, &space_info_ktype, info->space_info_kobj, "%s", alloc_name(found->flags)); if (ret) { kfree(found); return ret; } *space_info = found; list_add_rcu(&found->list, &info->space_info); if (flags & BTRFS_BLOCK_GROUP_DATA) info->data_sinfo = found; return ret; } static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags) { u64 extra_flags = chunk_to_extended(flags) & BTRFS_EXTENDED_PROFILE_MASK; write_seqlock(&fs_info->profiles_lock); if (flags & BTRFS_BLOCK_GROUP_DATA) fs_info->avail_data_alloc_bits |= extra_flags; if (flags & BTRFS_BLOCK_GROUP_METADATA) fs_info->avail_metadata_alloc_bits |= extra_flags; if (flags & BTRFS_BLOCK_GROUP_SYSTEM) fs_info->avail_system_alloc_bits |= extra_flags; write_sequnlock(&fs_info->profiles_lock); } /* * returns target flags in extended format or 0 if restripe for this * chunk_type is not in progress * * should be called with either volume_mutex or balance_lock held */ static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags) { struct btrfs_balance_control *bctl = fs_info->balance_ctl; u64 target = 0; if (!bctl) return 0; if (flags & BTRFS_BLOCK_GROUP_DATA && bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) { target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target; } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM && bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) { target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target; } else if (flags & BTRFS_BLOCK_GROUP_METADATA && bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) { target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target; } return target; } /* * @flags: available profiles in extended format (see ctree.h) * * Returns reduced profile in chunk format. If profile changing is in * progress (either running or paused) picks the target profile (if it's * already available), otherwise falls back to plain reducing. */ static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags) { u64 num_devices = root->fs_info->fs_devices->rw_devices; u64 target; u64 raid_type; u64 allowed = 0; /* * see if restripe for this chunk_type is in progress, if so * try to reduce to the target profile */ spin_lock(&root->fs_info->balance_lock); target = get_restripe_target(root->fs_info, flags); if (target) { /* pick target profile only if it's already available */ if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) { spin_unlock(&root->fs_info->balance_lock); return extended_to_chunk(target); } } spin_unlock(&root->fs_info->balance_lock); /* First, mask out the RAID levels which aren't possible */ for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) { if (num_devices >= btrfs_raid_array[raid_type].devs_min) allowed |= btrfs_raid_group[raid_type]; } allowed &= flags; if (allowed & BTRFS_BLOCK_GROUP_RAID6) allowed = BTRFS_BLOCK_GROUP_RAID6; else if (allowed & BTRFS_BLOCK_GROUP_RAID5) allowed = BTRFS_BLOCK_GROUP_RAID5; else if (allowed & BTRFS_BLOCK_GROUP_RAID10) allowed = BTRFS_BLOCK_GROUP_RAID10; else if (allowed & BTRFS_BLOCK_GROUP_RAID1) allowed = BTRFS_BLOCK_GROUP_RAID1; else if (allowed & BTRFS_BLOCK_GROUP_RAID0) allowed = BTRFS_BLOCK_GROUP_RAID0; flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK; return extended_to_chunk(flags | allowed); } static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags) { unsigned seq; u64 flags; do { flags = orig_flags; seq = read_seqbegin(&root->fs_info->profiles_lock); if (flags & BTRFS_BLOCK_GROUP_DATA) flags |= root->fs_info->avail_data_alloc_bits; else if (flags & BTRFS_BLOCK_GROUP_SYSTEM) flags |= root->fs_info->avail_system_alloc_bits; else if (flags & BTRFS_BLOCK_GROUP_METADATA) flags |= root->fs_info->avail_metadata_alloc_bits; } while (read_seqretry(&root->fs_info->profiles_lock, seq)); return btrfs_reduce_alloc_profile(root, flags); } u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data) { u64 flags; u64 ret; if (data) flags = BTRFS_BLOCK_GROUP_DATA; else if (root == root->fs_info->chunk_root) flags = BTRFS_BLOCK_GROUP_SYSTEM; else flags = BTRFS_BLOCK_GROUP_METADATA; ret = get_alloc_profile(root, flags); return ret; } /* * This will check the space that the inode allocates from to make sure we have * enough space for bytes. */ int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes) { struct btrfs_space_info *data_sinfo; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_fs_info *fs_info = root->fs_info; u64 used; int ret = 0; int need_commit = 2; int have_pinned_space; /* make sure bytes are sectorsize aligned */ bytes = ALIGN(bytes, root->sectorsize); if (btrfs_is_free_space_inode(inode)) { need_commit = 0; ASSERT(current->journal_info); } data_sinfo = fs_info->data_sinfo; if (!data_sinfo) goto alloc; again: /* make sure we have enough space to handle the data first */ spin_lock(&data_sinfo->lock); used = data_sinfo->bytes_used + data_sinfo->bytes_reserved + data_sinfo->bytes_pinned + data_sinfo->bytes_readonly + data_sinfo->bytes_may_use; if (used + bytes > data_sinfo->total_bytes) { struct btrfs_trans_handle *trans; /* * if we don't have enough free bytes in this space then we need * to alloc a new chunk. */ if (!data_sinfo->full) { u64 alloc_target; data_sinfo->force_alloc = CHUNK_ALLOC_FORCE; spin_unlock(&data_sinfo->lock); alloc: alloc_target = btrfs_get_alloc_profile(root, 1); /* * It is ugly that we don't call nolock join * transaction for the free space inode case here. * But it is safe because we only do the data space * reservation for the free space cache in the * transaction context, the common join transaction * just increase the counter of the current transaction * handler, doesn't try to acquire the trans_lock of * the fs. */ trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return PTR_ERR(trans); ret = do_chunk_alloc(trans, root->fs_info->extent_root, alloc_target, CHUNK_ALLOC_NO_FORCE); btrfs_end_transaction(trans, root); if (ret < 0) { if (ret != -ENOSPC) return ret; else { have_pinned_space = 1; goto commit_trans; } } if (!data_sinfo) data_sinfo = fs_info->data_sinfo; goto again; } /* * If we don't have enough pinned space to deal with this * allocation, and no removed chunk in current transaction, * don't bother committing the transaction. */ have_pinned_space = percpu_counter_compare( &data_sinfo->total_bytes_pinned, used + bytes - data_sinfo->total_bytes); spin_unlock(&data_sinfo->lock); /* commit the current transaction and try again */ commit_trans: if (need_commit && !atomic_read(&root->fs_info->open_ioctl_trans)) { need_commit--; if (need_commit > 0) btrfs_wait_ordered_roots(fs_info, -1); trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return PTR_ERR(trans); if (have_pinned_space >= 0 || test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags) || need_commit > 0) { ret = btrfs_commit_transaction(trans, root); if (ret) return ret; /* * make sure that all running delayed iput are * done */ down_write(&root->fs_info->delayed_iput_sem); up_write(&root->fs_info->delayed_iput_sem); goto again; } else { btrfs_end_transaction(trans, root); } } trace_btrfs_space_reservation(root->fs_info, "space_info:enospc", data_sinfo->flags, bytes, 1); return -ENOSPC; } ret = btrfs_qgroup_reserve(root, write_bytes); if (ret) goto out; data_sinfo->bytes_may_use += bytes; trace_btrfs_space_reservation(root->fs_info, "space_info", data_sinfo->flags, bytes, 1); out: spin_unlock(&data_sinfo->lock); return ret; } /* * Called if we need to clear a data reservation for this inode. */ void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes) { struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_space_info *data_sinfo; /* make sure bytes are sectorsize aligned */ bytes = ALIGN(bytes, root->sectorsize); data_sinfo = root->fs_info->data_sinfo; spin_lock(&data_sinfo->lock); WARN_ON(data_sinfo->bytes_may_use < bytes); data_sinfo->bytes_may_use -= bytes; trace_btrfs_space_reservation(root->fs_info, "space_info", data_sinfo->flags, bytes, 0); spin_unlock(&data_sinfo->lock); } static void force_metadata_allocation(struct btrfs_fs_info *info) { struct list_head *head = &info->space_info; struct btrfs_space_info *found; rcu_read_lock(); list_for_each_entry_rcu(found, head, list) { if (found->flags & BTRFS_BLOCK_GROUP_METADATA) found->force_alloc = CHUNK_ALLOC_FORCE; } rcu_read_unlock(); } static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global) { return (global->size << 1); } static int should_alloc_chunk(struct btrfs_root *root, struct btrfs_space_info *sinfo, int force) { struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly; u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved; u64 thresh; if (force == CHUNK_ALLOC_FORCE) return 1; /* * We need to take into account the global rsv because for all intents * and purposes it's used space. Don't worry about locking the * global_rsv, it doesn't change except when the transaction commits. */ if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA) num_allocated += calc_global_rsv_need_space(global_rsv); /* * in limited mode, we want to have some free space up to * about 1% of the FS size. */ if (force == CHUNK_ALLOC_LIMITED) { thresh = btrfs_super_total_bytes(root->fs_info->super_copy); thresh = max_t(u64, 64 * 1024 * 1024, div_factor_fine(thresh, 1)); if (num_bytes - num_allocated < thresh) return 1; } if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8)) return 0; return 1; } static u64 get_profile_num_devs(struct btrfs_root *root, u64 type) { u64 num_dev; if (type & (BTRFS_BLOCK_GROUP_RAID10 | BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) num_dev = root->fs_info->fs_devices->rw_devices; else if (type & BTRFS_BLOCK_GROUP_RAID1) num_dev = 2; else num_dev = 1; /* DUP or single */ return num_dev; } /* * If @is_allocation is true, reserve space in the system space info necessary * for allocating a chunk, otherwise if it's false, reserve space necessary for * removing a chunk. */ void check_system_chunk(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 type) { struct btrfs_space_info *info; u64 left; u64 thresh; int ret = 0; u64 num_devs; /* * Needed because we can end up allocating a system chunk and for an * atomic and race free space reservation in the chunk block reserve. */ ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex)); info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM); spin_lock(&info->lock); left = info->total_bytes - info->bytes_used - info->bytes_pinned - info->bytes_reserved - info->bytes_readonly - info->bytes_may_use; spin_unlock(&info->lock); num_devs = get_profile_num_devs(root, type); /* num_devs device items to update and 1 chunk item to add or remove */ thresh = btrfs_calc_trunc_metadata_size(root, num_devs) + btrfs_calc_trans_metadata_size(root, 1); if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) { btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu", left, thresh, type); dump_space_info(info, 0, 0); } if (left < thresh) { u64 flags; flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0); /* * Ignore failure to create system chunk. We might end up not * needing it, as we might not need to COW all nodes/leafs from * the paths we visit in the chunk tree (they were already COWed * or created in the current transaction for example). */ ret = btrfs_alloc_chunk(trans, root, flags); } if (!ret) { ret = btrfs_block_rsv_add(root->fs_info->chunk_root, &root->fs_info->chunk_block_rsv, thresh, BTRFS_RESERVE_NO_FLUSH); if (!ret) trans->chunk_bytes_reserved += thresh; } } static int do_chunk_alloc(struct btrfs_trans_handle *trans, struct btrfs_root *extent_root, u64 flags, int force) { struct btrfs_space_info *space_info; struct btrfs_fs_info *fs_info = extent_root->fs_info; int wait_for_alloc = 0; int ret = 0; /* Don't re-enter if we're already allocating a chunk */ if (trans->allocating_chunk) return -ENOSPC; space_info = __find_space_info(extent_root->fs_info, flags); if (!space_info) { ret = update_space_info(extent_root->fs_info, flags, 0, 0, &space_info); BUG_ON(ret); /* -ENOMEM */ } BUG_ON(!space_info); /* Logic error */ again: spin_lock(&space_info->lock); if (force < space_info->force_alloc) force = space_info->force_alloc; if (space_info->full) { if (should_alloc_chunk(extent_root, space_info, force)) ret = -ENOSPC; else ret = 0; spin_unlock(&space_info->lock); return ret; } if (!should_alloc_chunk(extent_root, space_info, force)) { spin_unlock(&space_info->lock); return 0; } else if (space_info->chunk_alloc) { wait_for_alloc = 1; } else { space_info->chunk_alloc = 1; } spin_unlock(&space_info->lock); mutex_lock(&fs_info->chunk_mutex); /* * The chunk_mutex is held throughout the entirety of a chunk * allocation, so once we've acquired the chunk_mutex we know that the * other guy is done and we need to recheck and see if we should * allocate. */ if (wait_for_alloc) { mutex_unlock(&fs_info->chunk_mutex); wait_for_alloc = 0; goto again; } trans->allocating_chunk = true; /* * If we have mixed data/metadata chunks we want to make sure we keep * allocating mixed chunks instead of individual chunks. */ if (btrfs_mixed_space_info(space_info)) flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA); /* * if we're doing a data chunk, go ahead and make sure that * we keep a reasonable number of metadata chunks allocated in the * FS as well. */ if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) { fs_info->data_chunk_allocations++; if (!(fs_info->data_chunk_allocations % fs_info->metadata_ratio)) force_metadata_allocation(fs_info); } /* * Check if we have enough space in SYSTEM chunk because we may need * to update devices. */ check_system_chunk(trans, extent_root, flags); ret = btrfs_alloc_chunk(trans, extent_root, flags); trans->allocating_chunk = false; spin_lock(&space_info->lock); if (ret < 0 && ret != -ENOSPC) goto out; if (ret) space_info->full = 1; else ret = 1; space_info->force_alloc = CHUNK_ALLOC_NO_FORCE; out: space_info->chunk_alloc = 0; spin_unlock(&space_info->lock); mutex_unlock(&fs_info->chunk_mutex); /* * When we allocate a new chunk we reserve space in the chunk block * reserve to make sure we can COW nodes/leafs in the chunk tree or * add new nodes/leafs to it if we end up needing to do it when * inserting the chunk item and updating device items as part of the * second phase of chunk allocation, performed by * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a * large number of new block groups to create in our transaction * handle's new_bgs list to avoid exhausting the chunk block reserve * in extreme cases - like having a single transaction create many new * block groups when starting to write out the free space caches of all * the block groups that were made dirty during the lifetime of the * transaction. */ if (trans->can_flush_pending_bgs && trans->chunk_bytes_reserved >= (2 * 1024 * 1024ull)) { btrfs_create_pending_block_groups(trans, trans->root); btrfs_trans_release_chunk_metadata(trans); } return ret; } static int can_overcommit(struct btrfs_root *root, struct btrfs_space_info *space_info, u64 bytes, enum btrfs_reserve_flush_enum flush) { struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; u64 profile = btrfs_get_alloc_profile(root, 0); u64 space_size; u64 avail; u64 used; used = space_info->bytes_used + space_info->bytes_reserved + space_info->bytes_pinned + space_info->bytes_readonly; /* * We only want to allow over committing if we have lots of actual space * free, but if we don't have enough space to handle the global reserve * space then we could end up having a real enospc problem when trying * to allocate a chunk or some other such important allocation. */ spin_lock(&global_rsv->lock); space_size = calc_global_rsv_need_space(global_rsv); spin_unlock(&global_rsv->lock); if (used + space_size >= space_info->total_bytes) return 0; used += space_info->bytes_may_use; spin_lock(&root->fs_info->free_chunk_lock); avail = root->fs_info->free_chunk_space; spin_unlock(&root->fs_info->free_chunk_lock); /* * If we have dup, raid1 or raid10 then only half of the free * space is actually useable. For raid56, the space info used * doesn't include the parity drive, so we don't have to * change the math */ if (profile & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) avail >>= 1; /* * If we aren't flushing all things, let us overcommit up to * 1/2th of the space. If we can flush, don't let us overcommit * too much, let it overcommit up to 1/8 of the space. */ if (flush == BTRFS_RESERVE_FLUSH_ALL) avail >>= 3; else avail >>= 1; if (used + bytes < space_info->total_bytes + avail) return 1; return 0; } static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root, unsigned long nr_pages, int nr_items) { struct super_block *sb = root->fs_info->sb; if (down_read_trylock(&sb->s_umount)) { writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE); up_read(&sb->s_umount); } else { /* * We needn't worry the filesystem going from r/w to r/o though * we don't acquire ->s_umount mutex, because the filesystem * should guarantee the delalloc inodes list be empty after * the filesystem is readonly(all dirty pages are written to * the disk). */ btrfs_start_delalloc_roots(root->fs_info, 0, nr_items); if (!current->journal_info) btrfs_wait_ordered_roots(root->fs_info, nr_items); } } static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim) { u64 bytes; int nr; bytes = btrfs_calc_trans_metadata_size(root, 1); nr = (int)div64_u64(to_reclaim, bytes); if (!nr) nr = 1; return nr; } #define EXTENT_SIZE_PER_ITEM (256 * 1024) /* * shrink metadata reservation for delalloc */ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig, bool wait_ordered) { struct btrfs_block_rsv *block_rsv; struct btrfs_space_info *space_info; struct btrfs_trans_handle *trans; u64 delalloc_bytes; u64 max_reclaim; long time_left; unsigned long nr_pages; int loops; int items; enum btrfs_reserve_flush_enum flush; /* Calc the number of the pages we need flush for space reservation */ items = calc_reclaim_items_nr(root, to_reclaim); to_reclaim = items * EXTENT_SIZE_PER_ITEM; trans = (struct btrfs_trans_handle *)current->journal_info; block_rsv = &root->fs_info->delalloc_block_rsv; space_info = block_rsv->space_info; delalloc_bytes = percpu_counter_sum_positive( &root->fs_info->delalloc_bytes); if (delalloc_bytes == 0) { if (trans) return; if (wait_ordered) btrfs_wait_ordered_roots(root->fs_info, items); return; } loops = 0; while (delalloc_bytes && loops < 3) { max_reclaim = min(delalloc_bytes, to_reclaim); nr_pages = max_reclaim >> PAGE_CACHE_SHIFT; btrfs_writeback_inodes_sb_nr(root, nr_pages, items); /* * We need to wait for the async pages to actually start before * we do anything. */ max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages); if (!max_reclaim) goto skip_async; if (max_reclaim <= nr_pages) max_reclaim = 0; else max_reclaim -= nr_pages; wait_event(root->fs_info->async_submit_wait, atomic_read(&root->fs_info->async_delalloc_pages) <= (int)max_reclaim); skip_async: if (!trans) flush = BTRFS_RESERVE_FLUSH_ALL; else flush = BTRFS_RESERVE_NO_FLUSH; spin_lock(&space_info->lock); if (can_overcommit(root, space_info, orig, flush)) { spin_unlock(&space_info->lock); break; } spin_unlock(&space_info->lock); loops++; if (wait_ordered && !trans) { btrfs_wait_ordered_roots(root->fs_info, items); } else { time_left = schedule_timeout_killable(1); if (time_left) break; } delalloc_bytes = percpu_counter_sum_positive( &root->fs_info->delalloc_bytes); } } /** * maybe_commit_transaction - possibly commit the transaction if its ok to * @root - the root we're allocating for * @bytes - the number of bytes we want to reserve * @force - force the commit * * This will check to make sure that committing the transaction will actually * get us somewhere and then commit the transaction if it does. Otherwise it * will return -ENOSPC. */ static int may_commit_transaction(struct btrfs_root *root, struct btrfs_space_info *space_info, u64 bytes, int force) { struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv; struct btrfs_trans_handle *trans; trans = (struct btrfs_trans_handle *)current->journal_info; if (trans) return -EAGAIN; if (force) goto commit; /* See if there is enough pinned space to make this reservation */ if (percpu_counter_compare(&space_info->total_bytes_pinned, bytes) >= 0) goto commit; /* * See if there is some space in the delayed insertion reservation for * this reservation. */ if (space_info != delayed_rsv->space_info) return -ENOSPC; spin_lock(&delayed_rsv->lock); if (percpu_counter_compare(&space_info->total_bytes_pinned, bytes - delayed_rsv->size) >= 0) { spin_unlock(&delayed_rsv->lock); return -ENOSPC; } spin_unlock(&delayed_rsv->lock); commit: trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return -ENOSPC; return btrfs_commit_transaction(trans, root); } enum flush_state { FLUSH_DELAYED_ITEMS_NR = 1, FLUSH_DELAYED_ITEMS = 2, FLUSH_DELALLOC = 3, FLUSH_DELALLOC_WAIT = 4, ALLOC_CHUNK = 5, COMMIT_TRANS = 6, }; static int flush_space(struct btrfs_root *root, struct btrfs_space_info *space_info, u64 num_bytes, u64 orig_bytes, int state) { struct btrfs_trans_handle *trans; int nr; int ret = 0; switch (state) { case FLUSH_DELAYED_ITEMS_NR: case FLUSH_DELAYED_ITEMS: if (state == FLUSH_DELAYED_ITEMS_NR) nr = calc_reclaim_items_nr(root, num_bytes) * 2; else nr = -1; trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); break; } ret = btrfs_run_delayed_items_nr(trans, root, nr); btrfs_end_transaction(trans, root); break; case FLUSH_DELALLOC: case FLUSH_DELALLOC_WAIT: shrink_delalloc(root, num_bytes * 2, orig_bytes, state == FLUSH_DELALLOC_WAIT); break; case ALLOC_CHUNK: trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); break; } ret = do_chunk_alloc(trans, root->fs_info->extent_root, btrfs_get_alloc_profile(root, 0), CHUNK_ALLOC_NO_FORCE); btrfs_end_transaction(trans, root); if (ret == -ENOSPC) ret = 0; break; case COMMIT_TRANS: ret = may_commit_transaction(root, space_info, orig_bytes, 0); break; default: ret = -ENOSPC; break; } return ret; } static inline u64 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root, struct btrfs_space_info *space_info) { u64 used; u64 expected; u64 to_reclaim; to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024, 16 * 1024 * 1024); spin_lock(&space_info->lock); if (can_overcommit(root, space_info, to_reclaim, BTRFS_RESERVE_FLUSH_ALL)) { to_reclaim = 0; goto out; } used = space_info->bytes_used + space_info->bytes_reserved + space_info->bytes_pinned + space_info->bytes_readonly + space_info->bytes_may_use; if (can_overcommit(root, space_info, 1024 * 1024, BTRFS_RESERVE_FLUSH_ALL)) expected = div_factor_fine(space_info->total_bytes, 95); else expected = div_factor_fine(space_info->total_bytes, 90); if (used > expected) to_reclaim = used - expected; else to_reclaim = 0; to_reclaim = min(to_reclaim, space_info->bytes_may_use + space_info->bytes_reserved); out: spin_unlock(&space_info->lock); return to_reclaim; } static inline int need_do_async_reclaim(struct btrfs_space_info *space_info, struct btrfs_fs_info *fs_info, u64 used) { u64 thresh = div_factor_fine(space_info->total_bytes, 98); /* If we're just plain full then async reclaim just slows us down. */ if (space_info->bytes_used >= thresh) return 0; return (used >= thresh && !btrfs_fs_closing(fs_info) && !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state)); } static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info, struct btrfs_fs_info *fs_info, int flush_state) { u64 used; spin_lock(&space_info->lock); /* * We run out of space and have not got any free space via flush_space, * so don't bother doing async reclaim. */ if (flush_state > COMMIT_TRANS && space_info->full) { spin_unlock(&space_info->lock); return 0; } used = space_info->bytes_used + space_info->bytes_reserved + space_info->bytes_pinned + space_info->bytes_readonly + space_info->bytes_may_use; if (need_do_async_reclaim(space_info, fs_info, used)) { spin_unlock(&space_info->lock); return 1; } spin_unlock(&space_info->lock); return 0; } static void btrfs_async_reclaim_metadata_space(struct work_struct *work) { struct btrfs_fs_info *fs_info; struct btrfs_space_info *space_info; u64 to_reclaim; int flush_state; fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work); space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root, space_info); if (!to_reclaim) return; flush_state = FLUSH_DELAYED_ITEMS_NR; do { flush_space(fs_info->fs_root, space_info, to_reclaim, to_reclaim, flush_state); flush_state++; if (!btrfs_need_do_async_reclaim(space_info, fs_info, flush_state)) return; } while (flush_state < COMMIT_TRANS); } void btrfs_init_async_reclaim_work(struct work_struct *work) { INIT_WORK(work, btrfs_async_reclaim_metadata_space); } /** * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space * @root - the root we're allocating for * @block_rsv - the block_rsv we're allocating for * @orig_bytes - the number of bytes we want * @flush - whether or not we can flush to make our reservation * * This will reserve orgi_bytes number of bytes from the space info associated * with the block_rsv. If there is not enough space it will make an attempt to * flush out space to make room. It will do this by flushing delalloc if * possible or committing the transaction. If flush is 0 then no attempts to * regain reservations will be made and this will fail if there is not enough * space already. */ static int reserve_metadata_bytes(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, u64 orig_bytes, enum btrfs_reserve_flush_enum flush) { struct btrfs_space_info *space_info = block_rsv->space_info; u64 used; u64 num_bytes = orig_bytes; int flush_state = FLUSH_DELAYED_ITEMS_NR; int ret = 0; bool flushing = false; again: ret = 0; spin_lock(&space_info->lock); /* * We only want to wait if somebody other than us is flushing and we * are actually allowed to flush all things. */ while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing && space_info->flush) { spin_unlock(&space_info->lock); /* * If we have a trans handle we can't wait because the flusher * may have to commit the transaction, which would mean we would * deadlock since we are waiting for the flusher to finish, but * hold the current transaction open. */ if (current->journal_info) return -EAGAIN; ret = wait_event_killable(space_info->wait, !space_info->flush); /* Must have been killed, return */ if (ret) return -EINTR; spin_lock(&space_info->lock); } ret = -ENOSPC; used = space_info->bytes_used + space_info->bytes_reserved + space_info->bytes_pinned + space_info->bytes_readonly + space_info->bytes_may_use; /* * The idea here is that we've not already over-reserved the block group * then we can go ahead and save our reservation first and then start * flushing if we need to. Otherwise if we've already overcommitted * lets start flushing stuff first and then come back and try to make * our reservation. */ if (used <= space_info->total_bytes) { if (used + orig_bytes <= space_info->total_bytes) { space_info->bytes_may_use += orig_bytes; trace_btrfs_space_reservation(root->fs_info, "space_info", space_info->flags, orig_bytes, 1); ret = 0; } else { /* * Ok set num_bytes to orig_bytes since we aren't * overocmmitted, this way we only try and reclaim what * we need. */ num_bytes = orig_bytes; } } else { /* * Ok we're over committed, set num_bytes to the overcommitted * amount plus the amount of bytes that we need for this * reservation. */ num_bytes = used - space_info->total_bytes + (orig_bytes * 2); } if (ret && can_overcommit(root, space_info, orig_bytes, flush)) { space_info->bytes_may_use += orig_bytes; trace_btrfs_space_reservation(root->fs_info, "space_info", space_info->flags, orig_bytes, 1); ret = 0; } /* * Couldn't make our reservation, save our place so while we're trying * to reclaim space we can actually use it instead of somebody else * stealing it from us. * * We make the other tasks wait for the flush only when we can flush * all things. */ if (ret && flush != BTRFS_RESERVE_NO_FLUSH) { flushing = true; space_info->flush = 1; } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { used += orig_bytes; /* * We will do the space reservation dance during log replay, * which means we won't have fs_info->fs_root set, so don't do * the async reclaim as we will panic. */ if (!root->fs_info->log_root_recovering && need_do_async_reclaim(space_info, root->fs_info, used) && !work_busy(&root->fs_info->async_reclaim_work)) queue_work(system_unbound_wq, &root->fs_info->async_reclaim_work); } spin_unlock(&space_info->lock); if (!ret || flush == BTRFS_RESERVE_NO_FLUSH) goto out; ret = flush_space(root, space_info, num_bytes, orig_bytes, flush_state); flush_state++; /* * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock * would happen. So skip delalloc flush. */ if (flush == BTRFS_RESERVE_FLUSH_LIMIT && (flush_state == FLUSH_DELALLOC || flush_state == FLUSH_DELALLOC_WAIT)) flush_state = ALLOC_CHUNK; if (!ret) goto again; else if (flush == BTRFS_RESERVE_FLUSH_LIMIT && flush_state < COMMIT_TRANS) goto again; else if (flush == BTRFS_RESERVE_FLUSH_ALL && flush_state <= COMMIT_TRANS) goto again; out: if (ret == -ENOSPC && unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) { struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; if (block_rsv != global_rsv && !block_rsv_use_bytes(global_rsv, orig_bytes)) ret = 0; } if (ret == -ENOSPC) trace_btrfs_space_reservation(root->fs_info, "space_info:enospc", space_info->flags, orig_bytes, 1); if (flushing) { spin_lock(&space_info->lock); space_info->flush = 0; wake_up_all(&space_info->wait); spin_unlock(&space_info->lock); } return ret; } static struct btrfs_block_rsv *get_block_rsv( const struct btrfs_trans_handle *trans, const struct btrfs_root *root) { struct btrfs_block_rsv *block_rsv = NULL; if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) || (root == root->fs_info->csum_root && trans->adding_csums) || (root == root->fs_info->uuid_root)) block_rsv = trans->block_rsv; if (!block_rsv) block_rsv = root->block_rsv; if (!block_rsv) block_rsv = &root->fs_info->empty_block_rsv; return block_rsv; } static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes) { int ret = -ENOSPC; spin_lock(&block_rsv->lock); if (block_rsv->reserved >= num_bytes) { block_rsv->reserved -= num_bytes; if (block_rsv->reserved < block_rsv->size) block_rsv->full = 0; ret = 0; } spin_unlock(&block_rsv->lock); return ret; } static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes, int update_size) { spin_lock(&block_rsv->lock); block_rsv->reserved += num_bytes; if (update_size) block_rsv->size += num_bytes; else if (block_rsv->reserved >= block_rsv->size) block_rsv->full = 1; spin_unlock(&block_rsv->lock); } int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *dest, u64 num_bytes, int min_factor) { struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; u64 min_bytes; if (global_rsv->space_info != dest->space_info) return -ENOSPC; spin_lock(&global_rsv->lock); min_bytes = div_factor(global_rsv->size, min_factor); if (global_rsv->reserved < min_bytes + num_bytes) { spin_unlock(&global_rsv->lock); return -ENOSPC; } global_rsv->reserved -= num_bytes; if (global_rsv->reserved < global_rsv->size) global_rsv->full = 0; spin_unlock(&global_rsv->lock); block_rsv_add_bytes(dest, num_bytes, 1); return 0; } static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *block_rsv, struct btrfs_block_rsv *dest, u64 num_bytes) { struct btrfs_space_info *space_info = block_rsv->space_info; spin_lock(&block_rsv->lock); if (num_bytes == (u64)-1) num_bytes = block_rsv->size; block_rsv->size -= num_bytes; if (block_rsv->reserved >= block_rsv->size) { num_bytes = block_rsv->reserved - block_rsv->size; block_rsv->reserved = block_rsv->size; block_rsv->full = 1; } else { num_bytes = 0; } spin_unlock(&block_rsv->lock); if (num_bytes > 0) { if (dest) { spin_lock(&dest->lock); if (!dest->full) { u64 bytes_to_add; bytes_to_add = dest->size - dest->reserved; bytes_to_add = min(num_bytes, bytes_to_add); dest->reserved += bytes_to_add; if (dest->reserved >= dest->size) dest->full = 1; num_bytes -= bytes_to_add; } spin_unlock(&dest->lock); } if (num_bytes) { spin_lock(&space_info->lock); space_info->bytes_may_use -= num_bytes; trace_btrfs_space_reservation(fs_info, "space_info", space_info->flags, num_bytes, 0); spin_unlock(&space_info->lock); } } } static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src, struct btrfs_block_rsv *dst, u64 num_bytes) { int ret; ret = block_rsv_use_bytes(src, num_bytes); if (ret) return ret; block_rsv_add_bytes(dst, num_bytes, 1); return 0; } void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type) { memset(rsv, 0, sizeof(*rsv)); spin_lock_init(&rsv->lock); rsv->type = type; } struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root, unsigned short type) { struct btrfs_block_rsv *block_rsv; struct btrfs_fs_info *fs_info = root->fs_info; block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS); if (!block_rsv) return NULL; btrfs_init_block_rsv(block_rsv, type); block_rsv->space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); return block_rsv; } void btrfs_free_block_rsv(struct btrfs_root *root, struct btrfs_block_rsv *rsv) { if (!rsv) return; btrfs_block_rsv_release(root, rsv, (u64)-1); kfree(rsv); } void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv) { kfree(rsv); } int btrfs_block_rsv_add(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, u64 num_bytes, enum btrfs_reserve_flush_enum flush) { int ret; if (num_bytes == 0) return 0; ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush); if (!ret) { block_rsv_add_bytes(block_rsv, num_bytes, 1); return 0; } return ret; } int btrfs_block_rsv_check(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, int min_factor) { u64 num_bytes = 0; int ret = -ENOSPC; if (!block_rsv) return 0; spin_lock(&block_rsv->lock); num_bytes = div_factor(block_rsv->size, min_factor); if (block_rsv->reserved >= num_bytes) ret = 0; spin_unlock(&block_rsv->lock); return ret; } int btrfs_block_rsv_refill(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, u64 min_reserved, enum btrfs_reserve_flush_enum flush) { u64 num_bytes = 0; int ret = -ENOSPC; if (!block_rsv) return 0; spin_lock(&block_rsv->lock); num_bytes = min_reserved; if (block_rsv->reserved >= num_bytes) ret = 0; else num_bytes -= block_rsv->reserved; spin_unlock(&block_rsv->lock); if (!ret) return 0; ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush); if (!ret) { block_rsv_add_bytes(block_rsv, num_bytes, 0); return 0; } return ret; } int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv, struct btrfs_block_rsv *dst_rsv, u64 num_bytes) { return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes); } void btrfs_block_rsv_release(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, u64 num_bytes) { struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; if (global_rsv == block_rsv || block_rsv->space_info != global_rsv->space_info) global_rsv = NULL; block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv, num_bytes); } /* * helper to calculate size of global block reservation. * the desired value is sum of space used by extent tree, * checksum tree and root tree */ static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info) { struct btrfs_space_info *sinfo; u64 num_bytes; u64 meta_used; u64 data_used; int csum_size = btrfs_super_csum_size(fs_info->super_copy); sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA); spin_lock(&sinfo->lock); data_used = sinfo->bytes_used; spin_unlock(&sinfo->lock); sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); spin_lock(&sinfo->lock); if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) data_used = 0; meta_used = sinfo->bytes_used; spin_unlock(&sinfo->lock); num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) * csum_size * 2; num_bytes += div_u64(data_used + meta_used, 50); if (num_bytes * 3 > meta_used) num_bytes = div_u64(meta_used, 3); return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10); } static void update_global_block_rsv(struct btrfs_fs_info *fs_info) { struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv; struct btrfs_space_info *sinfo = block_rsv->space_info; u64 num_bytes; num_bytes = calc_global_metadata_size(fs_info); spin_lock(&sinfo->lock); spin_lock(&block_rsv->lock); block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024); num_bytes = sinfo->bytes_used + sinfo->bytes_pinned + sinfo->bytes_reserved + sinfo->bytes_readonly + sinfo->bytes_may_use; if (sinfo->total_bytes > num_bytes) { num_bytes = sinfo->total_bytes - num_bytes; block_rsv->reserved += num_bytes; sinfo->bytes_may_use += num_bytes; trace_btrfs_space_reservation(fs_info, "space_info", sinfo->flags, num_bytes, 1); } if (block_rsv->reserved >= block_rsv->size) { num_bytes = block_rsv->reserved - block_rsv->size; sinfo->bytes_may_use -= num_bytes; trace_btrfs_space_reservation(fs_info, "space_info", sinfo->flags, num_bytes, 0); block_rsv->reserved = block_rsv->size; block_rsv->full = 1; } spin_unlock(&block_rsv->lock); spin_unlock(&sinfo->lock); } static void init_global_block_rsv(struct btrfs_fs_info *fs_info) { struct btrfs_space_info *space_info; space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM); fs_info->chunk_block_rsv.space_info = space_info; space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); fs_info->global_block_rsv.space_info = space_info; fs_info->delalloc_block_rsv.space_info = space_info; fs_info->trans_block_rsv.space_info = space_info; fs_info->empty_block_rsv.space_info = space_info; fs_info->delayed_block_rsv.space_info = space_info; fs_info->extent_root->block_rsv = &fs_info->global_block_rsv; fs_info->csum_root->block_rsv = &fs_info->global_block_rsv; fs_info->dev_root->block_rsv = &fs_info->global_block_rsv; fs_info->tree_root->block_rsv = &fs_info->global_block_rsv; if (fs_info->quota_root) fs_info->quota_root->block_rsv = &fs_info->global_block_rsv; fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv; update_global_block_rsv(fs_info); } static void release_global_block_rsv(struct btrfs_fs_info *fs_info) { block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL, (u64)-1); WARN_ON(fs_info->delalloc_block_rsv.size > 0); WARN_ON(fs_info->delalloc_block_rsv.reserved > 0); WARN_ON(fs_info->trans_block_rsv.size > 0); WARN_ON(fs_info->trans_block_rsv.reserved > 0); WARN_ON(fs_info->chunk_block_rsv.size > 0); WARN_ON(fs_info->chunk_block_rsv.reserved > 0); WARN_ON(fs_info->delayed_block_rsv.size > 0); WARN_ON(fs_info->delayed_block_rsv.reserved > 0); } void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans, struct btrfs_root *root) { if (!trans->block_rsv) return; if (!trans->bytes_reserved) return; trace_btrfs_space_reservation(root->fs_info, "transaction", trans->transid, trans->bytes_reserved, 0); btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved); trans->bytes_reserved = 0; } /* * To be called after all the new block groups attached to the transaction * handle have been created (btrfs_create_pending_block_groups()). */ void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->root->fs_info; if (!trans->chunk_bytes_reserved) return; WARN_ON_ONCE(!list_empty(&trans->new_bgs)); block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL, trans->chunk_bytes_reserved); trans->chunk_bytes_reserved = 0; } /* Can only return 0 or -ENOSPC */ int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans, struct inode *inode) { struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root); struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv; /* * We need to hold space in order to delete our orphan item once we've * added it, so this takes the reservation so we can release it later * when we are truly done with the orphan item. */ u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1); trace_btrfs_space_reservation(root->fs_info, "orphan", btrfs_ino(inode), num_bytes, 1); return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes); } void btrfs_orphan_release_metadata(struct inode *inode) { struct btrfs_root *root = BTRFS_I(inode)->root; u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1); trace_btrfs_space_reservation(root->fs_info, "orphan", btrfs_ino(inode), num_bytes, 0); btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes); } /* * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation * root: the root of the parent directory * rsv: block reservation * items: the number of items that we need do reservation * qgroup_reserved: used to return the reserved size in qgroup * * This function is used to reserve the space for snapshot/subvolume * creation and deletion. Those operations are different with the * common file/directory operations, they change two fs/file trees * and root tree, the number of items that the qgroup reserves is * different with the free space reservation. So we can not use * the space reseravtion mechanism in start_transaction(). */ int btrfs_subvolume_reserve_metadata(struct btrfs_root *root, struct btrfs_block_rsv *rsv, int items, u64 *qgroup_reserved, bool use_global_rsv) { u64 num_bytes; int ret; struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; if (root->fs_info->quota_enabled) { /* One for parent inode, two for dir entries */ num_bytes = 3 * root->nodesize; ret = btrfs_qgroup_reserve(root, num_bytes); if (ret) return ret; } else { num_bytes = 0; } *qgroup_reserved = num_bytes; num_bytes = btrfs_calc_trans_metadata_size(root, items); rsv->space_info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_METADATA); ret = btrfs_block_rsv_add(root, rsv, num_bytes, BTRFS_RESERVE_FLUSH_ALL); if (ret == -ENOSPC && use_global_rsv) ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes); if (ret) { if (*qgroup_reserved) btrfs_qgroup_free(root, *qgroup_reserved); } return ret; } void btrfs_subvolume_release_metadata(struct btrfs_root *root, struct btrfs_block_rsv *rsv, u64 qgroup_reserved) { btrfs_block_rsv_release(root, rsv, (u64)-1); } /** * drop_outstanding_extent - drop an outstanding extent * @inode: the inode we're dropping the extent for * @num_bytes: the number of bytes we're relaseing. * * This is called when we are freeing up an outstanding extent, either called * after an error or after an extent is written. This will return the number of * reserved extents that need to be freed. This must be called with * BTRFS_I(inode)->lock held. */ static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes) { unsigned drop_inode_space = 0; unsigned dropped_extents = 0; unsigned num_extents = 0; num_extents = (unsigned)div64_u64(num_bytes + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE); ASSERT(num_extents); ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents); BTRFS_I(inode)->outstanding_extents -= num_extents; if (BTRFS_I(inode)->outstanding_extents == 0 && test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED, &BTRFS_I(inode)->runtime_flags)) drop_inode_space = 1; /* * If we have more or the same amount of outsanding extents than we have * reserved then we need to leave the reserved extents count alone. */ if (BTRFS_I(inode)->outstanding_extents >= BTRFS_I(inode)->reserved_extents) return drop_inode_space; dropped_extents = BTRFS_I(inode)->reserved_extents - BTRFS_I(inode)->outstanding_extents; BTRFS_I(inode)->reserved_extents -= dropped_extents; return dropped_extents + drop_inode_space; } /** * calc_csum_metadata_size - return the amount of metada space that must be * reserved/free'd for the given bytes. * @inode: the inode we're manipulating * @num_bytes: the number of bytes in question * @reserve: 1 if we are reserving space, 0 if we are freeing space * * This adjusts the number of csum_bytes in the inode and then returns the * correct amount of metadata that must either be reserved or freed. We * calculate how many checksums we can fit into one leaf and then divide the * number of bytes that will need to be checksumed by this value to figure out * how many checksums will be required. If we are adding bytes then the number * may go up and we will return the number of additional bytes that must be * reserved. If it is going down we will return the number of bytes that must * be freed. * * This must be called with BTRFS_I(inode)->lock held. */ static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes, int reserve) { struct btrfs_root *root = BTRFS_I(inode)->root; u64 old_csums, num_csums; if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM && BTRFS_I(inode)->csum_bytes == 0) return 0; old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes); if (reserve) BTRFS_I(inode)->csum_bytes += num_bytes; else BTRFS_I(inode)->csum_bytes -= num_bytes; num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes); /* No change, no need to reserve more */ if (old_csums == num_csums) return 0; if (reserve) return btrfs_calc_trans_metadata_size(root, num_csums - old_csums); return btrfs_calc_trans_metadata_size(root, old_csums - num_csums); } int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) { struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv; u64 to_reserve = 0; u64 csum_bytes; unsigned nr_extents = 0; int extra_reserve = 0; enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL; int ret = 0; bool delalloc_lock = true; u64 to_free = 0; unsigned dropped; /* If we are a free space inode we need to not flush since we will be in * the middle of a transaction commit. We also don't need the delalloc * mutex since we won't race with anybody. We need this mostly to make * lockdep shut its filthy mouth. */ if (btrfs_is_free_space_inode(inode)) { flush = BTRFS_RESERVE_NO_FLUSH; delalloc_lock = false; } if (flush != BTRFS_RESERVE_NO_FLUSH && btrfs_transaction_in_commit(root->fs_info)) schedule_timeout(1); if (delalloc_lock) mutex_lock(&BTRFS_I(inode)->delalloc_mutex); num_bytes = ALIGN(num_bytes, root->sectorsize); spin_lock(&BTRFS_I(inode)->lock); nr_extents = (unsigned)div64_u64(num_bytes + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE); BTRFS_I(inode)->outstanding_extents += nr_extents; nr_extents = 0; if (BTRFS_I(inode)->outstanding_extents > BTRFS_I(inode)->reserved_extents) nr_extents = BTRFS_I(inode)->outstanding_extents - BTRFS_I(inode)->reserved_extents; /* * Add an item to reserve for updating the inode when we complete the * delalloc io. */ if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED, &BTRFS_I(inode)->runtime_flags)) { nr_extents++; extra_reserve = 1; } to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents); to_reserve += calc_csum_metadata_size(inode, num_bytes, 1); csum_bytes = BTRFS_I(inode)->csum_bytes; spin_unlock(&BTRFS_I(inode)->lock); if (root->fs_info->quota_enabled) { ret = btrfs_qgroup_reserve(root, nr_extents * root->nodesize); if (ret) goto out_fail; } ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush); if (unlikely(ret)) { if (root->fs_info->quota_enabled) btrfs_qgroup_free(root, nr_extents * root->nodesize); goto out_fail; } spin_lock(&BTRFS_I(inode)->lock); if (extra_reserve) { set_bit(BTRFS_INODE_DELALLOC_META_RESERVED, &BTRFS_I(inode)->runtime_flags); nr_extents--; } BTRFS_I(inode)->reserved_extents += nr_extents; spin_unlock(&BTRFS_I(inode)->lock); if (delalloc_lock) mutex_unlock(&BTRFS_I(inode)->delalloc_mutex); if (to_reserve) trace_btrfs_space_reservation(root->fs_info, "delalloc", btrfs_ino(inode), to_reserve, 1); block_rsv_add_bytes(block_rsv, to_reserve, 1); return 0; out_fail: spin_lock(&BTRFS_I(inode)->lock); dropped = drop_outstanding_extent(inode, num_bytes); /* * If the inodes csum_bytes is the same as the original * csum_bytes then we know we haven't raced with any free()ers * so we can just reduce our inodes csum bytes and carry on. */ if (BTRFS_I(inode)->csum_bytes == csum_bytes) { calc_csum_metadata_size(inode, num_bytes, 0); } else { u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes; u64 bytes; /* * This is tricky, but first we need to figure out how much we * free'd from any free-ers that occured during this * reservation, so we reset ->csum_bytes to the csum_bytes * before we dropped our lock, and then call the free for the * number of bytes that were freed while we were trying our * reservation. */ bytes = csum_bytes - BTRFS_I(inode)->csum_bytes; BTRFS_I(inode)->csum_bytes = csum_bytes; to_free = calc_csum_metadata_size(inode, bytes, 0); /* * Now we need to see how much we would have freed had we not * been making this reservation and our ->csum_bytes were not * artificially inflated. */ BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes; bytes = csum_bytes - orig_csum_bytes; bytes = calc_csum_metadata_size(inode, bytes, 0); /* * Now reset ->csum_bytes to what it should be. If bytes is * more than to_free then we would have free'd more space had we * not had an artificially high ->csum_bytes, so we need to free * the remainder. If bytes is the same or less then we don't * need to do anything, the other free-ers did the correct * thing. */ BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes; if (bytes > to_free) to_free = bytes - to_free; else to_free = 0; } spin_unlock(&BTRFS_I(inode)->lock); if (dropped) to_free += btrfs_calc_trans_metadata_size(root, dropped); if (to_free) { btrfs_block_rsv_release(root, block_rsv, to_free); trace_btrfs_space_reservation(root->fs_info, "delalloc", btrfs_ino(inode), to_free, 0); } if (delalloc_lock) mutex_unlock(&BTRFS_I(inode)->delalloc_mutex); return ret; } /** * btrfs_delalloc_release_metadata - release a metadata reservation for an inode * @inode: the inode to release the reservation for * @num_bytes: the number of bytes we're releasing * * This will release the metadata reservation for an inode. This can be called * once we complete IO for a given set of bytes to release their metadata * reservations. */ void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes) { struct btrfs_root *root = BTRFS_I(inode)->root; u64 to_free = 0; unsigned dropped; num_bytes = ALIGN(num_bytes, root->sectorsize); spin_lock(&BTRFS_I(inode)->lock); dropped = drop_outstanding_extent(inode, num_bytes); if (num_bytes) to_free = calc_csum_metadata_size(inode, num_bytes, 0); spin_unlock(&BTRFS_I(inode)->lock); if (dropped > 0) to_free += btrfs_calc_trans_metadata_size(root, dropped); if (btrfs_test_is_dummy_root(root)) return; trace_btrfs_space_reservation(root->fs_info, "delalloc", btrfs_ino(inode), to_free, 0); btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv, to_free); } /** * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc * @inode: inode we're writing to * @num_bytes: the number of bytes we want to allocate * * This will do the following things * * o reserve space in the data space info for num_bytes * o reserve space in the metadata space info based on number of outstanding * extents and how much csums will be needed * o add to the inodes ->delalloc_bytes * o add it to the fs_info's delalloc inodes list. * * This will return 0 for success and -ENOSPC if there is no space left. */ int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes) { int ret; ret = btrfs_check_data_free_space(inode, num_bytes, num_bytes); if (ret) return ret; ret = btrfs_delalloc_reserve_metadata(inode, num_bytes); if (ret) { btrfs_free_reserved_data_space(inode, num_bytes); return ret; } return 0; } /** * btrfs_delalloc_release_space - release data and metadata space for delalloc * @inode: inode we're releasing space for * @num_bytes: the number of bytes we want to free up * * This must be matched with a call to btrfs_delalloc_reserve_space. This is * called in the case that we don't need the metadata AND data reservations * anymore. So if there is an error or we insert an inline extent. * * This function will release the metadata space that was not used and will * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes * list if there are no delalloc bytes left. */ void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes) { btrfs_delalloc_release_metadata(inode, num_bytes); btrfs_free_reserved_data_space(inode, num_bytes); } static int update_block_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, int alloc) { struct btrfs_block_group_cache *cache = NULL; struct btrfs_fs_info *info = root->fs_info; u64 total = num_bytes; u64 old_val; u64 byte_in_group; int factor; /* block accounting for super block */ spin_lock(&info->delalloc_root_lock); old_val = btrfs_super_bytes_used(info->super_copy); if (alloc) old_val += num_bytes; else old_val -= num_bytes; btrfs_set_super_bytes_used(info->super_copy, old_val); spin_unlock(&info->delalloc_root_lock); while (total) { cache = btrfs_lookup_block_group(info, bytenr); if (!cache) return -ENOENT; if (cache->flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) factor = 2; else factor = 1; /* * If this block group has free space cache written out, we * need to make sure to load it if we are removing space. This * is because we need the unpinning stage to actually add the * space back to the block group, otherwise we will leak space. */ if (!alloc && cache->cached == BTRFS_CACHE_NO) cache_block_group(cache, 1); byte_in_group = bytenr - cache->key.objectid; WARN_ON(byte_in_group > cache->key.offset); spin_lock(&cache->space_info->lock); spin_lock(&cache->lock); if (btrfs_test_opt(root, SPACE_CACHE) && cache->disk_cache_state < BTRFS_DC_CLEAR) cache->disk_cache_state = BTRFS_DC_CLEAR; old_val = btrfs_block_group_used(&cache->item); num_bytes = min(total, cache->key.offset - byte_in_group); if (alloc) { old_val += num_bytes; btrfs_set_block_group_used(&cache->item, old_val); cache->reserved -= num_bytes; cache->space_info->bytes_reserved -= num_bytes; cache->space_info->bytes_used += num_bytes; cache->space_info->disk_used += num_bytes * factor; spin_unlock(&cache->lock); spin_unlock(&cache->space_info->lock); } else { old_val -= num_bytes; btrfs_set_block_group_used(&cache->item, old_val); cache->pinned += num_bytes; cache->space_info->bytes_pinned += num_bytes; cache->space_info->bytes_used -= num_bytes; cache->space_info->disk_used -= num_bytes * factor; spin_unlock(&cache->lock); spin_unlock(&cache->space_info->lock); set_extent_dirty(info->pinned_extents, bytenr, bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL); /* * No longer have used bytes in this block group, queue * it for deletion. */ if (old_val == 0) { spin_lock(&info->unused_bgs_lock); if (list_empty(&cache->bg_list)) { btrfs_get_block_group(cache); list_add_tail(&cache->bg_list, &info->unused_bgs); } spin_unlock(&info->unused_bgs_lock); } } spin_lock(&trans->transaction->dirty_bgs_lock); if (list_empty(&cache->dirty_list)) { list_add_tail(&cache->dirty_list, &trans->transaction->dirty_bgs); trans->transaction->num_dirty_bgs++; btrfs_get_block_group(cache); } spin_unlock(&trans->transaction->dirty_bgs_lock); btrfs_put_block_group(cache); total -= num_bytes; bytenr += num_bytes; } return 0; } static u64 first_logical_byte(struct btrfs_root *root, u64 search_start) { struct btrfs_block_group_cache *cache; u64 bytenr; spin_lock(&root->fs_info->block_group_cache_lock); bytenr = root->fs_info->first_logical_byte; spin_unlock(&root->fs_info->block_group_cache_lock); if (bytenr < (u64)-1) return bytenr; cache = btrfs_lookup_first_block_group(root->fs_info, search_start); if (!cache) return 0; bytenr = cache->key.objectid; btrfs_put_block_group(cache); return bytenr; } static int pin_down_extent(struct btrfs_root *root, struct btrfs_block_group_cache *cache, u64 bytenr, u64 num_bytes, int reserved) { spin_lock(&cache->space_info->lock); spin_lock(&cache->lock); cache->pinned += num_bytes; cache->space_info->bytes_pinned += num_bytes; if (reserved) { cache->reserved -= num_bytes; cache->space_info->bytes_reserved -= num_bytes; } spin_unlock(&cache->lock); spin_unlock(&cache->space_info->lock); set_extent_dirty(root->fs_info->pinned_extents, bytenr, bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL); if (reserved) trace_btrfs_reserved_extent_free(root, bytenr, num_bytes); return 0; } /* * this function must be called within transaction */ int btrfs_pin_extent(struct btrfs_root *root, u64 bytenr, u64 num_bytes, int reserved) { struct btrfs_block_group_cache *cache; cache = btrfs_lookup_block_group(root->fs_info, bytenr); BUG_ON(!cache); /* Logic error */ pin_down_extent(root, cache, bytenr, num_bytes, reserved); btrfs_put_block_group(cache); return 0; } /* * this function must be called within transaction */ int btrfs_pin_extent_for_log_replay(struct btrfs_root *root, u64 bytenr, u64 num_bytes) { struct btrfs_block_group_cache *cache; int ret; cache = btrfs_lookup_block_group(root->fs_info, bytenr); if (!cache) return -EINVAL; /* * pull in the free space cache (if any) so that our pin * removes the free space from the cache. We have load_only set * to one because the slow code to read in the free extents does check * the pinned extents. */ cache_block_group(cache, 1); pin_down_extent(root, cache, bytenr, num_bytes, 0); /* remove us from the free space cache (if we're there at all) */ ret = btrfs_remove_free_space(cache, bytenr, num_bytes); btrfs_put_block_group(cache); return ret; } static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes) { int ret; struct btrfs_block_group_cache *block_group; struct btrfs_caching_control *caching_ctl; block_group = btrfs_lookup_block_group(root->fs_info, start); if (!block_group) return -EINVAL; cache_block_group(block_group, 0); caching_ctl = get_caching_control(block_group); if (!caching_ctl) { /* Logic error */ BUG_ON(!block_group_cache_done(block_group)); ret = btrfs_remove_free_space(block_group, start, num_bytes); } else { mutex_lock(&caching_ctl->mutex); if (start >= caching_ctl->progress) { ret = add_excluded_extent(root, start, num_bytes); } else if (start + num_bytes <= caching_ctl->progress) { ret = btrfs_remove_free_space(block_group, start, num_bytes); } else { num_bytes = caching_ctl->progress - start; ret = btrfs_remove_free_space(block_group, start, num_bytes); if (ret) goto out_lock; num_bytes = (start + num_bytes) - caching_ctl->progress; start = caching_ctl->progress; ret = add_excluded_extent(root, start, num_bytes); } out_lock: mutex_unlock(&caching_ctl->mutex); put_caching_control(caching_ctl); } btrfs_put_block_group(block_group); return ret; } int btrfs_exclude_logged_extents(struct btrfs_root *log, struct extent_buffer *eb) { struct btrfs_file_extent_item *item; struct btrfs_key key; int found_type; int i; if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS)) return 0; for (i = 0; i < btrfs_header_nritems(eb); i++) { btrfs_item_key_to_cpu(eb, &key, i); if (key.type != BTRFS_EXTENT_DATA_KEY) continue; item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item); found_type = btrfs_file_extent_type(eb, item); if (found_type == BTRFS_FILE_EXTENT_INLINE) continue; if (btrfs_file_extent_disk_bytenr(eb, item) == 0) continue; key.objectid = btrfs_file_extent_disk_bytenr(eb, item); key.offset = btrfs_file_extent_disk_num_bytes(eb, item); __exclude_logged_extent(log, key.objectid, key.offset); } return 0; } /** * btrfs_update_reserved_bytes - update the block_group and space info counters * @cache: The cache we are manipulating * @num_bytes: The number of bytes in question * @reserve: One of the reservation enums * @delalloc: The blocks are allocated for the delalloc write * * This is called by the allocator when it reserves space, or by somebody who is * freeing space that was never actually used on disk. For example if you * reserve some space for a new leaf in transaction A and before transaction A * commits you free that leaf, you call this with reserve set to 0 in order to * clear the reservation. * * Metadata reservations should be called with RESERVE_ALLOC so we do the proper * ENOSPC accounting. For data we handle the reservation through clearing the * delalloc bits in the io_tree. We have to do this since we could end up * allocating less disk space for the amount of data we have reserved in the * case of compression. * * If this is a reservation and the block group has become read only we cannot * make the reservation and return -EAGAIN, otherwise this function always * succeeds. */ static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache, u64 num_bytes, int reserve, int delalloc) { struct btrfs_space_info *space_info = cache->space_info; int ret = 0; spin_lock(&space_info->lock); spin_lock(&cache->lock); if (reserve != RESERVE_FREE) { if (cache->ro) { ret = -EAGAIN; } else { cache->reserved += num_bytes; space_info->bytes_reserved += num_bytes; if (reserve == RESERVE_ALLOC) { trace_btrfs_space_reservation(cache->fs_info, "space_info", space_info->flags, num_bytes, 0); space_info->bytes_may_use -= num_bytes; } if (delalloc) cache->delalloc_bytes += num_bytes; } } else { if (cache->ro) space_info->bytes_readonly += num_bytes; cache->reserved -= num_bytes; space_info->bytes_reserved -= num_bytes; if (delalloc) cache->delalloc_bytes -= num_bytes; } spin_unlock(&cache->lock); spin_unlock(&space_info->lock); return ret; } void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_caching_control *next; struct btrfs_caching_control *caching_ctl; struct btrfs_block_group_cache *cache; down_write(&fs_info->commit_root_sem); list_for_each_entry_safe(caching_ctl, next, &fs_info->caching_block_groups, list) { cache = caching_ctl->block_group; if (block_group_cache_done(cache)) { cache->last_byte_to_unpin = (u64)-1; list_del_init(&caching_ctl->list); put_caching_control(caching_ctl); } else { cache->last_byte_to_unpin = caching_ctl->progress; } } if (fs_info->pinned_extents == &fs_info->freed_extents[0]) fs_info->pinned_extents = &fs_info->freed_extents[1]; else fs_info->pinned_extents = &fs_info->freed_extents[0]; up_write(&fs_info->commit_root_sem); update_global_block_rsv(fs_info); } static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end, const bool return_free_space) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_block_group_cache *cache = NULL; struct btrfs_space_info *space_info; struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; u64 len; bool readonly; while (start <= end) { readonly = false; if (!cache || start >= cache->key.objectid + cache->key.offset) { if (cache) btrfs_put_block_group(cache); cache = btrfs_lookup_block_group(fs_info, start); BUG_ON(!cache); /* Logic error */ } len = cache->key.objectid + cache->key.offset - start; len = min(len, end + 1 - start); if (start < cache->last_byte_to_unpin) { len = min(len, cache->last_byte_to_unpin - start); if (return_free_space) btrfs_add_free_space(cache, start, len); } start += len; space_info = cache->space_info; spin_lock(&space_info->lock); spin_lock(&cache->lock); cache->pinned -= len; space_info->bytes_pinned -= len; space_info->max_extent_size = 0; percpu_counter_add(&space_info->total_bytes_pinned, -len); if (cache->ro) { space_info->bytes_readonly += len; readonly = true; } spin_unlock(&cache->lock); if (!readonly && global_rsv->space_info == space_info) { spin_lock(&global_rsv->lock); if (!global_rsv->full) { len = min(len, global_rsv->size - global_rsv->reserved); global_rsv->reserved += len; space_info->bytes_may_use += len; if (global_rsv->reserved >= global_rsv->size) global_rsv->full = 1; } spin_unlock(&global_rsv->lock); } spin_unlock(&space_info->lock); } if (cache) btrfs_put_block_group(cache); return 0; } int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_block_group_cache *block_group, *tmp; struct list_head *deleted_bgs; struct extent_io_tree *unpin; u64 start; u64 end; int ret; if (fs_info->pinned_extents == &fs_info->freed_extents[0]) unpin = &fs_info->freed_extents[1]; else unpin = &fs_info->freed_extents[0]; while (!trans->aborted) { mutex_lock(&fs_info->unused_bg_unpin_mutex); ret = find_first_extent_bit(unpin, 0, &start, &end, EXTENT_DIRTY, NULL); if (ret) { mutex_unlock(&fs_info->unused_bg_unpin_mutex); break; } if (btrfs_test_opt(root, DISCARD)) ret = btrfs_discard_extent(root, start, end + 1 - start, NULL); clear_extent_dirty(unpin, start, end, GFP_NOFS); unpin_extent_range(root, start, end, true); mutex_unlock(&fs_info->unused_bg_unpin_mutex); cond_resched(); } /* * Transaction is finished. We don't need the lock anymore. We * do need to clean up the block groups in case of a transaction * abort. */ deleted_bgs = &trans->transaction->deleted_bgs; list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) { u64 trimmed = 0; ret = -EROFS; if (!trans->aborted) ret = btrfs_discard_extent(root, block_group->key.objectid, block_group->key.offset, &trimmed); list_del_init(&block_group->bg_list); btrfs_put_block_group_trimming(block_group); btrfs_put_block_group(block_group); if (ret) { const char *errstr = btrfs_decode_error(ret); btrfs_warn(fs_info, "Discard failed while removing blockgroup: errno=%d %s\n", ret, errstr); } } return 0; } static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes, u64 owner, u64 root_objectid) { struct btrfs_space_info *space_info; u64 flags; if (owner < BTRFS_FIRST_FREE_OBJECTID) { if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID) flags = BTRFS_BLOCK_GROUP_SYSTEM; else flags = BTRFS_BLOCK_GROUP_METADATA; } else { flags = BTRFS_BLOCK_GROUP_DATA; } space_info = __find_space_info(fs_info, flags); BUG_ON(!space_info); /* Logic bug */ percpu_counter_add(&space_info->total_bytes_pinned, num_bytes); } static int __btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_delayed_ref_node *node, u64 parent, u64 root_objectid, u64 owner_objectid, u64 owner_offset, int refs_to_drop, struct btrfs_delayed_extent_op *extent_op) { struct btrfs_key key; struct btrfs_path *path; struct btrfs_fs_info *info = root->fs_info; struct btrfs_root *extent_root = info->extent_root; struct extent_buffer *leaf; struct btrfs_extent_item *ei; struct btrfs_extent_inline_ref *iref; int ret; int is_data; int extent_slot = 0; int found_extent = 0; int num_to_del = 1; int no_quota = node->no_quota; u32 item_size; u64 refs; u64 bytenr = node->bytenr; u64 num_bytes = node->num_bytes; int last_ref = 0; bool skinny_metadata = btrfs_fs_incompat(root->fs_info, SKINNY_METADATA); if (!info->quota_enabled || !is_fstree(root_objectid)) no_quota = 1; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = 1; path->leave_spinning = 1; is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID; BUG_ON(!is_data && refs_to_drop != 1); if (is_data) skinny_metadata = 0; ret = lookup_extent_backref(trans, extent_root, path, &iref, bytenr, num_bytes, parent, root_objectid, owner_objectid, owner_offset); if (ret == 0) { extent_slot = path->slots[0]; while (extent_slot >= 0) { btrfs_item_key_to_cpu(path->nodes[0], &key, extent_slot); if (key.objectid != bytenr) break; if (key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == num_bytes) { found_extent = 1; break; } if (key.type == BTRFS_METADATA_ITEM_KEY && key.offset == owner_objectid) { found_extent = 1; break; } if (path->slots[0] - extent_slot > 5) break; extent_slot--; } #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot); if (found_extent && item_size < sizeof(*ei)) found_extent = 0; #endif if (!found_extent) { BUG_ON(iref); ret = remove_extent_backref(trans, extent_root, path, NULL, refs_to_drop, is_data, &last_ref); if (ret) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } btrfs_release_path(path); path->leave_spinning = 1; key.objectid = bytenr; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = num_bytes; if (!is_data && skinny_metadata) { key.type = BTRFS_METADATA_ITEM_KEY; key.offset = owner_objectid; } ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1); if (ret > 0 && skinny_metadata && path->slots[0]) { /* * Couldn't find our skinny metadata item, * see if we have ye olde extent item. */ path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid == bytenr && key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == num_bytes) ret = 0; } if (ret > 0 && skinny_metadata) { skinny_metadata = false; key.objectid = bytenr; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = num_bytes; btrfs_release_path(path); ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1); } if (ret) { btrfs_err(info, "umm, got %d back from search, was looking for %llu", ret, bytenr); if (ret > 0) btrfs_print_leaf(extent_root, path->nodes[0]); } if (ret < 0) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } extent_slot = path->slots[0]; } } else if (WARN_ON(ret == -ENOENT)) { btrfs_print_leaf(extent_root, path->nodes[0]); btrfs_err(info, "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu", bytenr, parent, root_objectid, owner_objectid, owner_offset); btrfs_abort_transaction(trans, extent_root, ret); goto out; } else { btrfs_abort_transaction(trans, extent_root, ret); goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, extent_slot); #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 if (item_size < sizeof(*ei)) { BUG_ON(found_extent || extent_slot != path->slots[0]); ret = convert_extent_item_v0(trans, extent_root, path, owner_objectid, 0); if (ret < 0) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } btrfs_release_path(path); path->leave_spinning = 1; key.objectid = bytenr; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = num_bytes; ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1); if (ret) { btrfs_err(info, "umm, got %d back from search, was looking for %llu", ret, bytenr); btrfs_print_leaf(extent_root, path->nodes[0]); } if (ret < 0) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } extent_slot = path->slots[0]; leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, extent_slot); } #endif BUG_ON(item_size < sizeof(*ei)); ei = btrfs_item_ptr(leaf, extent_slot, struct btrfs_extent_item); if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID && key.type == BTRFS_EXTENT_ITEM_KEY) { struct btrfs_tree_block_info *bi; BUG_ON(item_size < sizeof(*ei) + sizeof(*bi)); bi = (struct btrfs_tree_block_info *)(ei + 1); WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi)); } refs = btrfs_extent_refs(leaf, ei); if (refs < refs_to_drop) { btrfs_err(info, "trying to drop %d refs but we only have %Lu " "for bytenr %Lu", refs_to_drop, refs, bytenr); ret = -EINVAL; btrfs_abort_transaction(trans, extent_root, ret); goto out; } refs -= refs_to_drop; if (refs > 0) { if (extent_op) __run_delayed_extent_op(extent_op, leaf, ei); /* * In the case of inline back ref, reference count will * be updated by remove_extent_backref */ if (iref) { BUG_ON(!found_extent); } else { btrfs_set_extent_refs(leaf, ei, refs); btrfs_mark_buffer_dirty(leaf); } if (found_extent) { ret = remove_extent_backref(trans, extent_root, path, iref, refs_to_drop, is_data, &last_ref); if (ret) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } } add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid, root_objectid); } else { if (found_extent) { BUG_ON(is_data && refs_to_drop != extent_data_ref_count(path, iref)); if (iref) { BUG_ON(path->slots[0] != extent_slot); } else { BUG_ON(path->slots[0] != extent_slot + 1); path->slots[0] = extent_slot; num_to_del = 2; } } last_ref = 1; ret = btrfs_del_items(trans, extent_root, path, path->slots[0], num_to_del); if (ret) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } btrfs_release_path(path); if (is_data) { ret = btrfs_del_csums(trans, root, bytenr, num_bytes); if (ret) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } } ret = update_block_group(trans, root, bytenr, num_bytes, 0); if (ret) { btrfs_abort_transaction(trans, extent_root, ret); goto out; } } btrfs_release_path(path); out: btrfs_free_path(path); return ret; } /* * when we free an block, it is possible (and likely) that we free the last * delayed ref for that extent as well. This searches the delayed ref tree for * a given extent, and if there are no other delayed refs to be processed, it * removes it from the tree. */ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr) { struct btrfs_delayed_ref_head *head; struct btrfs_delayed_ref_root *delayed_refs; int ret = 0; delayed_refs = &trans->transaction->delayed_refs; spin_lock(&delayed_refs->lock); head = btrfs_find_delayed_ref_head(trans, bytenr); if (!head) goto out_delayed_unlock; spin_lock(&head->lock); if (!list_empty(&head->ref_list)) goto out; if (head->extent_op) { if (!head->must_insert_reserved) goto out; btrfs_free_delayed_extent_op(head->extent_op); head->extent_op = NULL; } /* * waiting for the lock here would deadlock. If someone else has it * locked they are already in the process of dropping it anyway */ if (!mutex_trylock(&head->mutex)) goto out; /* * at this point we have a head with no other entries. Go * ahead and process it. */ head->node.in_tree = 0; rb_erase(&head->href_node, &delayed_refs->href_root); atomic_dec(&delayed_refs->num_entries); /* * we don't take a ref on the node because we're removing it from the * tree, so we just steal the ref the tree was holding. */ delayed_refs->num_heads--; if (head->processing == 0) delayed_refs->num_heads_ready--; head->processing = 0; spin_unlock(&head->lock); spin_unlock(&delayed_refs->lock); BUG_ON(head->extent_op); if (head->must_insert_reserved) ret = 1; mutex_unlock(&head->mutex); btrfs_put_delayed_ref(&head->node); return ret; out: spin_unlock(&head->lock); out_delayed_unlock: spin_unlock(&delayed_refs->lock); return 0; } void btrfs_free_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, u64 parent, int last_ref) { int pin = 1; int ret; if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) { ret = btrfs_add_delayed_tree_ref(root->fs_info, trans, buf->start, buf->len, parent, root->root_key.objectid, btrfs_header_level(buf), BTRFS_DROP_DELAYED_REF, NULL, 0); BUG_ON(ret); /* -ENOMEM */ } if (!last_ref) return; if (btrfs_header_generation(buf) == trans->transid) { struct btrfs_block_group_cache *cache; if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) { ret = check_ref_cleanup(trans, root, buf->start); if (!ret) goto out; } cache = btrfs_lookup_block_group(root->fs_info, buf->start); if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) { pin_down_extent(root, cache, buf->start, buf->len, 1); btrfs_put_block_group(cache); goto out; } WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)); btrfs_add_free_space(cache, buf->start, buf->len); btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0); btrfs_put_block_group(cache); trace_btrfs_reserved_extent_free(root, buf->start, buf->len); pin = 0; } out: if (pin) add_pinned_bytes(root->fs_info, buf->len, btrfs_header_level(buf), root->root_key.objectid); /* * Deleting the buffer, clear the corrupt flag since it doesn't matter * anymore. */ clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags); } /* Can return -ENOMEM */ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid, u64 owner, u64 offset, int no_quota) { int ret; struct btrfs_fs_info *fs_info = root->fs_info; if (btrfs_test_is_dummy_root(root)) return 0; add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid); /* * tree log blocks never actually go into the extent allocation * tree, just update pinning info and exit early. */ if (root_objectid == BTRFS_TREE_LOG_OBJECTID) { WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID); /* unlocks the pinned mutex */ btrfs_pin_extent(root, bytenr, num_bytes, 1); ret = 0; } else if (owner < BTRFS_FIRST_FREE_OBJECTID) { ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr, num_bytes, parent, root_objectid, (int)owner, BTRFS_DROP_DELAYED_REF, NULL, no_quota); } else { ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr, num_bytes, parent, root_objectid, owner, offset, BTRFS_DROP_DELAYED_REF, NULL, no_quota); } return ret; } /* * when we wait for progress in the block group caching, its because * our allocation attempt failed at least once. So, we must sleep * and let some progress happen before we try again. * * This function will sleep at least once waiting for new free space to * show up, and then it will check the block group free space numbers * for our min num_bytes. Another option is to have it go ahead * and look in the rbtree for a free extent of a given size, but this * is a good start. * * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using * any of the information in this block group. */ static noinline void wait_block_group_cache_progress(struct btrfs_block_group_cache *cache, u64 num_bytes) { struct btrfs_caching_control *caching_ctl; caching_ctl = get_caching_control(cache); if (!caching_ctl) return; wait_event(caching_ctl->wait, block_group_cache_done(cache) || (cache->free_space_ctl->free_space >= num_bytes)); put_caching_control(caching_ctl); } static noinline int wait_block_group_cache_done(struct btrfs_block_group_cache *cache) { struct btrfs_caching_control *caching_ctl; int ret = 0; caching_ctl = get_caching_control(cache); if (!caching_ctl) return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0; wait_event(caching_ctl->wait, block_group_cache_done(cache)); if (cache->cached == BTRFS_CACHE_ERROR) ret = -EIO; put_caching_control(caching_ctl); return ret; } int __get_raid_index(u64 flags) { if (flags & BTRFS_BLOCK_GROUP_RAID10) return BTRFS_RAID_RAID10; else if (flags & BTRFS_BLOCK_GROUP_RAID1) return BTRFS_RAID_RAID1; else if (flags & BTRFS_BLOCK_GROUP_DUP) return BTRFS_RAID_DUP; else if (flags & BTRFS_BLOCK_GROUP_RAID0) return BTRFS_RAID_RAID0; else if (flags & BTRFS_BLOCK_GROUP_RAID5) return BTRFS_RAID_RAID5; else if (flags & BTRFS_BLOCK_GROUP_RAID6) return BTRFS_RAID_RAID6; return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */ } int get_block_group_index(struct btrfs_block_group_cache *cache) { return __get_raid_index(cache->flags); } static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = { [BTRFS_RAID_RAID10] = "raid10", [BTRFS_RAID_RAID1] = "raid1", [BTRFS_RAID_DUP] = "dup", [BTRFS_RAID_RAID0] = "raid0", [BTRFS_RAID_SINGLE] = "single", [BTRFS_RAID_RAID5] = "raid5", [BTRFS_RAID_RAID6] = "raid6", }; static const char *get_raid_name(enum btrfs_raid_types type) { if (type >= BTRFS_NR_RAID_TYPES) return NULL; return btrfs_raid_type_names[type]; } enum btrfs_loop_type { LOOP_CACHING_NOWAIT = 0, LOOP_CACHING_WAIT = 1, LOOP_ALLOC_CHUNK = 2, LOOP_NO_EMPTY_SIZE = 3, }; static inline void btrfs_lock_block_group(struct btrfs_block_group_cache *cache, int delalloc) { if (delalloc) down_read(&cache->data_rwsem); } static inline void btrfs_grab_block_group(struct btrfs_block_group_cache *cache, int delalloc) { btrfs_get_block_group(cache); if (delalloc) down_read(&cache->data_rwsem); } static struct btrfs_block_group_cache * btrfs_lock_cluster(struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, int delalloc) { struct btrfs_block_group_cache *used_bg; bool locked = false; again: spin_lock(&cluster->refill_lock); if (locked) { if (used_bg == cluster->block_group) return used_bg; up_read(&used_bg->data_rwsem); btrfs_put_block_group(used_bg); } used_bg = cluster->block_group; if (!used_bg) return NULL; if (used_bg == block_group) return used_bg; btrfs_get_block_group(used_bg); if (!delalloc) return used_bg; if (down_read_trylock(&used_bg->data_rwsem)) return used_bg; spin_unlock(&cluster->refill_lock); down_read(&used_bg->data_rwsem); locked = true; goto again; } static inline void btrfs_release_block_group(struct btrfs_block_group_cache *cache, int delalloc) { if (delalloc) up_read(&cache->data_rwsem); btrfs_put_block_group(cache); } /* * walks the btree of allocated extents and find a hole of a given size. * The key ins is changed to record the hole: * ins->objectid == start position * ins->flags = BTRFS_EXTENT_ITEM_KEY * ins->offset == the size of the hole. * Any available blocks before search_start are skipped. * * If there is no suitable free space, we will record the max size of * the free space extent currently. */ static noinline int find_free_extent(struct btrfs_root *orig_root, u64 num_bytes, u64 empty_size, u64 hint_byte, struct btrfs_key *ins, u64 flags, int delalloc) { int ret = 0; struct btrfs_root *root = orig_root->fs_info->extent_root; struct btrfs_free_cluster *last_ptr = NULL; struct btrfs_block_group_cache *block_group = NULL; u64 search_start = 0; u64 max_extent_size = 0; int empty_cluster = 2 * 1024 * 1024; struct btrfs_space_info *space_info; int loop = 0; int index = __get_raid_index(flags); int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ? RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC; bool failed_cluster_refill = false; bool failed_alloc = false; bool use_cluster = true; bool have_caching_bg = false; WARN_ON(num_bytes < root->sectorsize); ins->type = BTRFS_EXTENT_ITEM_KEY; ins->objectid = 0; ins->offset = 0; trace_find_free_extent(orig_root, num_bytes, empty_size, flags); space_info = __find_space_info(root->fs_info, flags); if (!space_info) { btrfs_err(root->fs_info, "No space info for %llu", flags); return -ENOSPC; } /* * If our free space is heavily fragmented we may not be able to make * big contiguous allocations, so instead of doing the expensive search * for free space, simply return ENOSPC with our max_extent_size so we * can go ahead and search for a more manageable chunk. * * If our max_extent_size is large enough for our allocation simply * disable clustering since we will likely not be able to find enough * space to create a cluster and induce latency trying. */ if (unlikely(space_info->max_extent_size)) { spin_lock(&space_info->lock); if (space_info->max_extent_size && num_bytes > space_info->max_extent_size) { ins->offset = space_info->max_extent_size; spin_unlock(&space_info->lock); return -ENOSPC; } else if (space_info->max_extent_size) { use_cluster = false; } spin_unlock(&space_info->lock); } /* * If the space info is for both data and metadata it means we have a * small filesystem and we can't use the clustering stuff. */ if (btrfs_mixed_space_info(space_info)) use_cluster = false; if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) { last_ptr = &root->fs_info->meta_alloc_cluster; if (!btrfs_test_opt(root, SSD)) empty_cluster = 64 * 1024; } if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster && btrfs_test_opt(root, SSD)) { last_ptr = &root->fs_info->data_alloc_cluster; } if (last_ptr) { spin_lock(&last_ptr->lock); if (last_ptr->block_group) hint_byte = last_ptr->window_start; spin_unlock(&last_ptr->lock); } search_start = max(search_start, first_logical_byte(root, 0)); search_start = max(search_start, hint_byte); if (!last_ptr) empty_cluster = 0; if (search_start == hint_byte) { block_group = btrfs_lookup_block_group(root->fs_info, search_start); /* * we don't want to use the block group if it doesn't match our * allocation bits, or if its not cached. * * However if we are re-searching with an ideal block group * picked out then we don't care that the block group is cached. */ if (block_group && block_group_bits(block_group, flags) && block_group->cached != BTRFS_CACHE_NO) { down_read(&space_info->groups_sem); if (list_empty(&block_group->list) || block_group->ro) { /* * someone is removing this block group, * we can't jump into the have_block_group * target because our list pointers are not * valid */ btrfs_put_block_group(block_group); up_read(&space_info->groups_sem); } else { index = get_block_group_index(block_group); btrfs_lock_block_group(block_group, delalloc); goto have_block_group; } } else if (block_group) { btrfs_put_block_group(block_group); } } search: have_caching_bg = false; down_read(&space_info->groups_sem); list_for_each_entry(block_group, &space_info->block_groups[index], list) { u64 offset; int cached; btrfs_grab_block_group(block_group, delalloc); search_start = block_group->key.objectid; /* * this can happen if we end up cycling through all the * raid types, but we want to make sure we only allocate * for the proper type. */ if (!block_group_bits(block_group, flags)) { u64 extra = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10; /* * if they asked for extra copies and this block group * doesn't provide them, bail. This does allow us to * fill raid0 from raid1. */ if ((flags & extra) && !(block_group->flags & extra)) goto loop; } have_block_group: cached = block_group_cache_done(block_group); if (unlikely(!cached)) { ret = cache_block_group(block_group, 0); BUG_ON(ret < 0); ret = 0; } if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) goto loop; if (unlikely(block_group->ro)) goto loop; /* * Ok we want to try and use the cluster allocator, so * lets look there */ if (last_ptr) { struct btrfs_block_group_cache *used_block_group; unsigned long aligned_cluster; /* * the refill lock keeps out other * people trying to start a new cluster */ used_block_group = btrfs_lock_cluster(block_group, last_ptr, delalloc); if (!used_block_group) goto refill_cluster; if (used_block_group != block_group && (used_block_group->ro || !block_group_bits(used_block_group, flags))) goto release_cluster; offset = btrfs_alloc_from_cluster(used_block_group, last_ptr, num_bytes, used_block_group->key.objectid, &max_extent_size); if (offset) { /* we have a block, we're done */ spin_unlock(&last_ptr->refill_lock); trace_btrfs_reserve_extent_cluster(root, used_block_group, search_start, num_bytes); if (used_block_group != block_group) { btrfs_release_block_group(block_group, delalloc); block_group = used_block_group; } goto checks; } WARN_ON(last_ptr->block_group != used_block_group); release_cluster: /* If we are on LOOP_NO_EMPTY_SIZE, we can't * set up a new clusters, so lets just skip it * and let the allocator find whatever block * it can find. If we reach this point, we * will have tried the cluster allocator * plenty of times and not have found * anything, so we are likely way too * fragmented for the clustering stuff to find * anything. * * However, if the cluster is taken from the * current block group, release the cluster * first, so that we stand a better chance of * succeeding in the unclustered * allocation. */ if (loop >= LOOP_NO_EMPTY_SIZE && used_block_group != block_group) { spin_unlock(&last_ptr->refill_lock); btrfs_release_block_group(used_block_group, delalloc); goto unclustered_alloc; } /* * this cluster didn't work out, free it and * start over */ btrfs_return_cluster_to_free_space(NULL, last_ptr); if (used_block_group != block_group) btrfs_release_block_group(used_block_group, delalloc); refill_cluster: if (loop >= LOOP_NO_EMPTY_SIZE) { spin_unlock(&last_ptr->refill_lock); goto unclustered_alloc; } aligned_cluster = max_t(unsigned long, empty_cluster + empty_size, block_group->full_stripe_len); /* allocate a cluster in this block group */ ret = btrfs_find_space_cluster(root, block_group, last_ptr, search_start, num_bytes, aligned_cluster); if (ret == 0) { /* * now pull our allocation out of this * cluster */ offset = btrfs_alloc_from_cluster(block_group, last_ptr, num_bytes, search_start, &max_extent_size); if (offset) { /* we found one, proceed */ spin_unlock(&last_ptr->refill_lock); trace_btrfs_reserve_extent_cluster(root, block_group, search_start, num_bytes); goto checks; } } else if (!cached && loop > LOOP_CACHING_NOWAIT && !failed_cluster_refill) { spin_unlock(&last_ptr->refill_lock); failed_cluster_refill = true; wait_block_group_cache_progress(block_group, num_bytes + empty_cluster + empty_size); goto have_block_group; } /* * at this point we either didn't find a cluster * or we weren't able to allocate a block from our * cluster. Free the cluster we've been trying * to use, and go to the next block group */ btrfs_return_cluster_to_free_space(NULL, last_ptr); spin_unlock(&last_ptr->refill_lock); goto loop; } unclustered_alloc: spin_lock(&block_group->free_space_ctl->tree_lock); if (cached && block_group->free_space_ctl->free_space < num_bytes + empty_cluster + empty_size) { if (block_group->free_space_ctl->free_space > max_extent_size) max_extent_size = block_group->free_space_ctl->free_space; spin_unlock(&block_group->free_space_ctl->tree_lock); goto loop; } spin_unlock(&block_group->free_space_ctl->tree_lock); offset = btrfs_find_space_for_alloc(block_group, search_start, num_bytes, empty_size, &max_extent_size); /* * If we didn't find a chunk, and we haven't failed on this * block group before, and this block group is in the middle of * caching and we are ok with waiting, then go ahead and wait * for progress to be made, and set failed_alloc to true. * * If failed_alloc is true then we've already waited on this * block group once and should move on to the next block group. */ if (!offset && !failed_alloc && !cached && loop > LOOP_CACHING_NOWAIT) { wait_block_group_cache_progress(block_group, num_bytes + empty_size); failed_alloc = true; goto have_block_group; } else if (!offset) { if (!cached) have_caching_bg = true; goto loop; } checks: search_start = ALIGN(offset, root->stripesize); /* move on to the next group */ if (search_start + num_bytes > block_group->key.objectid + block_group->key.offset) { btrfs_add_free_space(block_group, offset, num_bytes); goto loop; } if (offset < search_start) btrfs_add_free_space(block_group, offset, search_start - offset); BUG_ON(offset > search_start); ret = btrfs_update_reserved_bytes(block_group, num_bytes, alloc_type, delalloc); if (ret == -EAGAIN) { btrfs_add_free_space(block_group, offset, num_bytes); goto loop; } /* we are all good, lets return */ ins->objectid = search_start; ins->offset = num_bytes; trace_btrfs_reserve_extent(orig_root, block_group, search_start, num_bytes); btrfs_release_block_group(block_group, delalloc); break; loop: failed_cluster_refill = false; failed_alloc = false; BUG_ON(index != get_block_group_index(block_group)); btrfs_release_block_group(block_group, delalloc); } up_read(&space_info->groups_sem); if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg) goto search; if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES) goto search; /* * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking * caching kthreads as we move along * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching * LOOP_ALLOC_CHUNK, force a chunk allocation and try again * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try * again */ if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) { index = 0; loop++; if (loop == LOOP_ALLOC_CHUNK) { struct btrfs_trans_handle *trans; int exist = 0; trans = current->journal_info; if (trans) exist = 1; else trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); goto out; } ret = do_chunk_alloc(trans, root, flags, CHUNK_ALLOC_FORCE); /* * Do not bail out on ENOSPC since we * can do more things. */ if (ret < 0 && ret != -ENOSPC) btrfs_abort_transaction(trans, root, ret); else ret = 0; if (!exist) btrfs_end_transaction(trans, root); if (ret) goto out; } if (loop == LOOP_NO_EMPTY_SIZE) { empty_size = 0; empty_cluster = 0; } goto search; } else if (!ins->objectid) { ret = -ENOSPC; } else if (ins->objectid) { ret = 0; } out: if (ret == -ENOSPC) { spin_lock(&space_info->lock); space_info->max_extent_size = max_extent_size; spin_unlock(&space_info->lock); ins->offset = max_extent_size; } return ret; } static void dump_space_info(struct btrfs_space_info *info, u64 bytes, int dump_block_groups) { struct btrfs_block_group_cache *cache; int index = 0; spin_lock(&info->lock); printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n", info->flags, info->total_bytes - info->bytes_used - info->bytes_pinned - info->bytes_reserved - info->bytes_readonly, (info->full) ? "" : "not "); printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, " "reserved=%llu, may_use=%llu, readonly=%llu\n", info->total_bytes, info->bytes_used, info->bytes_pinned, info->bytes_reserved, info->bytes_may_use, info->bytes_readonly); spin_unlock(&info->lock); if (!dump_block_groups) return; down_read(&info->groups_sem); again: list_for_each_entry(cache, &info->block_groups[index], list) { spin_lock(&cache->lock); printk(KERN_INFO "BTRFS: " "block group %llu has %llu bytes, " "%llu used %llu pinned %llu reserved %s\n", cache->key.objectid, cache->key.offset, btrfs_block_group_used(&cache->item), cache->pinned, cache->reserved, cache->ro ? "[readonly]" : ""); btrfs_dump_free_space(cache, bytes); spin_unlock(&cache->lock); } if (++index < BTRFS_NR_RAID_TYPES) goto again; up_read(&info->groups_sem); } int btrfs_reserve_extent(struct btrfs_root *root, u64 num_bytes, u64 min_alloc_size, u64 empty_size, u64 hint_byte, struct btrfs_key *ins, int is_data, int delalloc) { bool final_tried = num_bytes == min_alloc_size; u64 flags; int ret; flags = btrfs_get_alloc_profile(root, is_data); again: WARN_ON(num_bytes < root->sectorsize); ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins, flags, delalloc); if (ret == -ENOSPC) { if (!final_tried && ins->offset) { num_bytes = min(num_bytes >> 1, ins->offset); num_bytes = round_down(num_bytes, root->sectorsize); num_bytes = max(num_bytes, min_alloc_size); if (num_bytes == min_alloc_size) final_tried = true; goto again; } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) { struct btrfs_space_info *sinfo; sinfo = __find_space_info(root->fs_info, flags); btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu", flags, num_bytes); if (sinfo) dump_space_info(sinfo, num_bytes, 1); } } return ret; } static int __btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len, int pin, int delalloc) { struct btrfs_block_group_cache *cache; int ret = 0; cache = btrfs_lookup_block_group(root->fs_info, start); if (!cache) { btrfs_err(root->fs_info, "Unable to find block group for %llu", start); return -ENOSPC; } if (pin) pin_down_extent(root, cache, start, len, 1); else { if (btrfs_test_opt(root, DISCARD)) ret = btrfs_discard_extent(root, start, len, NULL); btrfs_add_free_space(cache, start, len); btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc); } btrfs_put_block_group(cache); trace_btrfs_reserved_extent_free(root, start, len); return ret; } int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len, int delalloc) { return __btrfs_free_reserved_extent(root, start, len, 0, delalloc); } int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root, u64 start, u64 len) { return __btrfs_free_reserved_extent(root, start, len, 1, 0); } static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent, u64 root_objectid, u64 flags, u64 owner, u64 offset, struct btrfs_key *ins, int ref_mod) { int ret; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_extent_item *extent_item; struct btrfs_extent_inline_ref *iref; struct btrfs_path *path; struct extent_buffer *leaf; int type; u32 size; if (parent > 0) type = BTRFS_SHARED_DATA_REF_KEY; else type = BTRFS_EXTENT_DATA_REF_KEY; size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type); path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->leave_spinning = 1; ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path, ins, size); if (ret) { btrfs_free_path(path); return ret; } leaf = path->nodes[0]; extent_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); btrfs_set_extent_refs(leaf, extent_item, ref_mod); btrfs_set_extent_generation(leaf, extent_item, trans->transid); btrfs_set_extent_flags(leaf, extent_item, flags | BTRFS_EXTENT_FLAG_DATA); iref = (struct btrfs_extent_inline_ref *)(extent_item + 1); btrfs_set_extent_inline_ref_type(leaf, iref, type); if (parent > 0) { struct btrfs_shared_data_ref *ref; ref = (struct btrfs_shared_data_ref *)(iref + 1); btrfs_set_extent_inline_ref_offset(leaf, iref, parent); btrfs_set_shared_data_ref_count(leaf, ref, ref_mod); } else { struct btrfs_extent_data_ref *ref; ref = (struct btrfs_extent_data_ref *)(&iref->offset); btrfs_set_extent_data_ref_root(leaf, ref, root_objectid); btrfs_set_extent_data_ref_objectid(leaf, ref, owner); btrfs_set_extent_data_ref_offset(leaf, ref, offset); btrfs_set_extent_data_ref_count(leaf, ref, ref_mod); } btrfs_mark_buffer_dirty(path->nodes[0]); btrfs_free_path(path); ret = update_block_group(trans, root, ins->objectid, ins->offset, 1); if (ret) { /* -ENOENT, logic error */ btrfs_err(fs_info, "update block group failed for %llu %llu", ins->objectid, ins->offset); BUG(); } trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset); return ret; } static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent, u64 root_objectid, u64 flags, struct btrfs_disk_key *key, int level, struct btrfs_key *ins, int no_quota) { int ret; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_extent_item *extent_item; struct btrfs_tree_block_info *block_info; struct btrfs_extent_inline_ref *iref; struct btrfs_path *path; struct extent_buffer *leaf; u32 size = sizeof(*extent_item) + sizeof(*iref); u64 num_bytes = ins->offset; bool skinny_metadata = btrfs_fs_incompat(root->fs_info, SKINNY_METADATA); if (!skinny_metadata) size += sizeof(*block_info); path = btrfs_alloc_path(); if (!path) { btrfs_free_and_pin_reserved_extent(root, ins->objectid, root->nodesize); return -ENOMEM; } path->leave_spinning = 1; ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path, ins, size); if (ret) { btrfs_free_path(path); btrfs_free_and_pin_reserved_extent(root, ins->objectid, root->nodesize); return ret; } leaf = path->nodes[0]; extent_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); btrfs_set_extent_refs(leaf, extent_item, 1); btrfs_set_extent_generation(leaf, extent_item, trans->transid); btrfs_set_extent_flags(leaf, extent_item, flags | BTRFS_EXTENT_FLAG_TREE_BLOCK); if (skinny_metadata) { iref = (struct btrfs_extent_inline_ref *)(extent_item + 1); num_bytes = root->nodesize; } else { block_info = (struct btrfs_tree_block_info *)(extent_item + 1); btrfs_set_tree_block_key(leaf, block_info, key); btrfs_set_tree_block_level(leaf, block_info, level); iref = (struct btrfs_extent_inline_ref *)(block_info + 1); } if (parent > 0) { BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_SHARED_BLOCK_REF_KEY); btrfs_set_extent_inline_ref_offset(leaf, iref, parent); } else { btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY); btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid); } btrfs_mark_buffer_dirty(leaf); btrfs_free_path(path); ret = update_block_group(trans, root, ins->objectid, root->nodesize, 1); if (ret) { /* -ENOENT, logic error */ btrfs_err(fs_info, "update block group failed for %llu %llu", ins->objectid, ins->offset); BUG(); } trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize); return ret; } int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 root_objectid, u64 owner, u64 offset, struct btrfs_key *ins) { int ret; BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID); ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid, ins->offset, 0, root_objectid, owner, offset, BTRFS_ADD_DELAYED_EXTENT, NULL, 0); return ret; } /* * this is used by the tree logging recovery code. It records that * an extent has been allocated and makes sure to clear the free * space cache bits as well */ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 root_objectid, u64 owner, u64 offset, struct btrfs_key *ins) { int ret; struct btrfs_block_group_cache *block_group; /* * Mixed block groups will exclude before processing the log so we only * need to do the exlude dance if this fs isn't mixed. */ if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) { ret = __exclude_logged_extent(root, ins->objectid, ins->offset); if (ret) return ret; } block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid); if (!block_group) return -EINVAL; ret = btrfs_update_reserved_bytes(block_group, ins->offset, RESERVE_ALLOC_NO_ACCOUNT, 0); BUG_ON(ret); /* logic error */ ret = alloc_reserved_file_extent(trans, root, 0, root_objectid, 0, owner, offset, ins, 1); btrfs_put_block_group(block_group); return ret; } static struct extent_buffer * btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, int level) { struct extent_buffer *buf; buf = btrfs_find_create_tree_block(root, bytenr); if (!buf) return ERR_PTR(-ENOMEM); btrfs_set_header_generation(buf, trans->transid); btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level); btrfs_tree_lock(buf); clean_tree_block(trans, root->fs_info, buf); clear_bit(EXTENT_BUFFER_STALE, &buf->bflags); btrfs_set_lock_blocking(buf); btrfs_set_buffer_uptodate(buf); if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) { buf->log_index = root->log_transid % 2; /* * we allow two log transactions at a time, use different * EXENT bit to differentiate dirty pages. */ if (buf->log_index == 0) set_extent_dirty(&root->dirty_log_pages, buf->start, buf->start + buf->len - 1, GFP_NOFS); else set_extent_new(&root->dirty_log_pages, buf->start, buf->start + buf->len - 1, GFP_NOFS); } else { buf->log_index = -1; set_extent_dirty(&trans->transaction->dirty_pages, buf->start, buf->start + buf->len - 1, GFP_NOFS); } trans->blocks_used++; /* this returns a buffer locked for blocking */ return buf; } static struct btrfs_block_rsv * use_block_rsv(struct btrfs_trans_handle *trans, struct btrfs_root *root, u32 blocksize) { struct btrfs_block_rsv *block_rsv; struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; int ret; bool global_updated = false; block_rsv = get_block_rsv(trans, root); if (unlikely(block_rsv->size == 0)) goto try_reserve; again: ret = block_rsv_use_bytes(block_rsv, blocksize); if (!ret) return block_rsv; if (block_rsv->failfast) return ERR_PTR(ret); if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) { global_updated = true; update_global_block_rsv(root->fs_info); goto again; } if (btrfs_test_opt(root, ENOSPC_DEBUG)) { static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL * 10, /*DEFAULT_RATELIMIT_BURST*/ 1); if (__ratelimit(&_rs)) WARN(1, KERN_DEBUG "BTRFS: block rsv returned %d\n", ret); } try_reserve: ret = reserve_metadata_bytes(root, block_rsv, blocksize, BTRFS_RESERVE_NO_FLUSH); if (!ret) return block_rsv; /* * If we couldn't reserve metadata bytes try and use some from * the global reserve if its space type is the same as the global * reservation. */ if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL && block_rsv->space_info == global_rsv->space_info) { ret = block_rsv_use_bytes(global_rsv, blocksize); if (!ret) return global_rsv; } return ERR_PTR(ret); } static void unuse_block_rsv(struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *block_rsv, u32 blocksize) { block_rsv_add_bytes(block_rsv, blocksize, 0); block_rsv_release_bytes(fs_info, block_rsv, NULL, 0); } /* * finds a free extent and does all the dirty work required for allocation * returns the tree buffer or an ERR_PTR on error. */ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent, u64 root_objectid, struct btrfs_disk_key *key, int level, u64 hint, u64 empty_size) { struct btrfs_key ins; struct btrfs_block_rsv *block_rsv; struct extent_buffer *buf; struct btrfs_delayed_extent_op *extent_op; u64 flags = 0; int ret; u32 blocksize = root->nodesize; bool skinny_metadata = btrfs_fs_incompat(root->fs_info, SKINNY_METADATA); if (btrfs_test_is_dummy_root(root)) { buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr, level); if (!IS_ERR(buf)) root->alloc_bytenr += blocksize; return buf; } block_rsv = use_block_rsv(trans, root, blocksize); if (IS_ERR(block_rsv)) return ERR_CAST(block_rsv); ret = btrfs_reserve_extent(root, blocksize, blocksize, empty_size, hint, &ins, 0, 0); if (ret) goto out_unuse; buf = btrfs_init_new_buffer(trans, root, ins.objectid, level); if (IS_ERR(buf)) { ret = PTR_ERR(buf); goto out_free_reserved; } if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) { if (parent == 0) parent = ins.objectid; flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; } else BUG_ON(parent > 0); if (root_objectid != BTRFS_TREE_LOG_OBJECTID) { extent_op = btrfs_alloc_delayed_extent_op(); if (!extent_op) { ret = -ENOMEM; goto out_free_buf; } if (key) memcpy(&extent_op->key, key, sizeof(extent_op->key)); else memset(&extent_op->key, 0, sizeof(extent_op->key)); extent_op->flags_to_set = flags; if (skinny_metadata) extent_op->update_key = 0; else extent_op->update_key = 1; extent_op->update_flags = 1; extent_op->is_data = 0; extent_op->level = level; ret = btrfs_add_delayed_tree_ref(root->fs_info, trans, ins.objectid, ins.offset, parent, root_objectid, level, BTRFS_ADD_DELAYED_EXTENT, extent_op, 0); if (ret) goto out_free_delayed; } return buf; out_free_delayed: btrfs_free_delayed_extent_op(extent_op); out_free_buf: free_extent_buffer(buf); out_free_reserved: btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0); out_unuse: unuse_block_rsv(root->fs_info, block_rsv, blocksize); return ERR_PTR(ret); } struct walk_control { u64 refs[BTRFS_MAX_LEVEL]; u64 flags[BTRFS_MAX_LEVEL]; struct btrfs_key update_progress; int stage; int level; int shared_level; int update_ref; int keep_locks; int reada_slot; int reada_count; int for_reloc; }; #define DROP_REFERENCE 1 #define UPDATE_BACKREF 2 static noinline void reada_walk_down(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct walk_control *wc, struct btrfs_path *path) { u64 bytenr; u64 generation; u64 refs; u64 flags; u32 nritems; u32 blocksize; struct btrfs_key key; struct extent_buffer *eb; int ret; int slot; int nread = 0; if (path->slots[wc->level] < wc->reada_slot) { wc->reada_count = wc->reada_count * 2 / 3; wc->reada_count = max(wc->reada_count, 2); } else { wc->reada_count = wc->reada_count * 3 / 2; wc->reada_count = min_t(int, wc->reada_count, BTRFS_NODEPTRS_PER_BLOCK(root)); } eb = path->nodes[wc->level]; nritems = btrfs_header_nritems(eb); blocksize = root->nodesize; for (slot = path->slots[wc->level]; slot < nritems; slot++) { if (nread >= wc->reada_count) break; cond_resched(); bytenr = btrfs_node_blockptr(eb, slot); generation = btrfs_node_ptr_generation(eb, slot); if (slot == path->slots[wc->level]) goto reada; if (wc->stage == UPDATE_BACKREF && generation <= root->root_key.offset) continue; /* We don't lock the tree block, it's OK to be racy here */ ret = btrfs_lookup_extent_info(trans, root, bytenr, wc->level - 1, 1, &refs, &flags); /* We don't care about errors in readahead. */ if (ret < 0) continue; BUG_ON(refs == 0); if (wc->stage == DROP_REFERENCE) { if (refs == 1) goto reada; if (wc->level == 1 && (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) continue; if (!wc->update_ref || generation <= root->root_key.offset) continue; btrfs_node_key_to_cpu(eb, &key, slot); ret = btrfs_comp_cpu_keys(&key, &wc->update_progress); if (ret < 0) continue; } else { if (wc->level == 1 && (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) continue; } reada: readahead_tree_block(root, bytenr); nread++; } wc->reada_slot = slot; } /* * TODO: Modify related function to add related node/leaf to dirty_extent_root, * for later qgroup accounting. * * Current, this function does nothing. */ static int account_leaf_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *eb) { int nr = btrfs_header_nritems(eb); int i, extent_type; struct btrfs_key key; struct btrfs_file_extent_item *fi; u64 bytenr, num_bytes; for (i = 0; i < nr; i++) { btrfs_item_key_to_cpu(eb, &key, i); if (key.type != BTRFS_EXTENT_DATA_KEY) continue; fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item); /* filter out non qgroup-accountable extents */ extent_type = btrfs_file_extent_type(eb, fi); if (extent_type == BTRFS_FILE_EXTENT_INLINE) continue; bytenr = btrfs_file_extent_disk_bytenr(eb, fi); if (!bytenr) continue; num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi); } return 0; } /* * Walk up the tree from the bottom, freeing leaves and any interior * nodes which have had all slots visited. If a node (leaf or * interior) is freed, the node above it will have it's slot * incremented. The root node will never be freed. * * At the end of this function, we should have a path which has all * slots incremented to the next position for a search. If we need to * read a new node it will be NULL and the node above it will have the * correct slot selected for a later read. * * If we increment the root nodes slot counter past the number of * elements, 1 is returned to signal completion of the search. */ static int adjust_slots_upwards(struct btrfs_root *root, struct btrfs_path *path, int root_level) { int level = 0; int nr, slot; struct extent_buffer *eb; if (root_level == 0) return 1; while (level <= root_level) { eb = path->nodes[level]; nr = btrfs_header_nritems(eb); path->slots[level]++; slot = path->slots[level]; if (slot >= nr || level == 0) { /* * Don't free the root - we will detect this * condition after our loop and return a * positive value for caller to stop walking the tree. */ if (level != root_level) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; free_extent_buffer(eb); path->nodes[level] = NULL; path->slots[level] = 0; } } else { /* * We have a valid slot to walk back down * from. Stop here so caller can process these * new nodes. */ break; } level++; } eb = path->nodes[root_level]; if (path->slots[root_level] >= btrfs_header_nritems(eb)) return 1; return 0; } /* * root_eb is the subtree root and is locked before this function is called. * TODO: Modify this function to mark all (including complete shared node) * to dirty_extent_root to allow it get accounted in qgroup. */ static int account_shared_subtree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *root_eb, u64 root_gen, int root_level) { int ret = 0; int level; struct extent_buffer *eb = root_eb; struct btrfs_path *path = NULL; BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL); BUG_ON(root_eb == NULL); if (!root->fs_info->quota_enabled) return 0; if (!extent_buffer_uptodate(root_eb)) { ret = btrfs_read_buffer(root_eb, root_gen); if (ret) goto out; } if (root_level == 0) { ret = account_leaf_items(trans, root, root_eb); goto out; } path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* * Walk down the tree. Missing extent blocks are filled in as * we go. Metadata is accounted every time we read a new * extent block. * * When we reach a leaf, we account for file extent items in it, * walk back up the tree (adjusting slot pointers as we go) * and restart the search process. */ extent_buffer_get(root_eb); /* For path */ path->nodes[root_level] = root_eb; path->slots[root_level] = 0; path->locks[root_level] = 0; /* so release_path doesn't try to unlock */ walk_down: level = root_level; while (level >= 0) { if (path->nodes[level] == NULL) { int parent_slot; u64 child_gen; u64 child_bytenr; /* We need to get child blockptr/gen from * parent before we can read it. */ eb = path->nodes[level + 1]; parent_slot = path->slots[level + 1]; child_bytenr = btrfs_node_blockptr(eb, parent_slot); child_gen = btrfs_node_ptr_generation(eb, parent_slot); eb = read_tree_block(root, child_bytenr, child_gen); if (IS_ERR(eb)) { ret = PTR_ERR(eb); goto out; } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); ret = -EIO; goto out; } path->nodes[level] = eb; path->slots[level] = 0; btrfs_tree_read_lock(eb); btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); path->locks[level] = BTRFS_READ_LOCK_BLOCKING; } if (level == 0) { ret = account_leaf_items(trans, root, path->nodes[level]); if (ret) goto out; /* Nonzero return here means we completed our search */ ret = adjust_slots_upwards(root, path, root_level); if (ret) break; /* Restart search with new slots */ goto walk_down; } level--; } ret = 0; out: btrfs_free_path(path); return ret; } /* * helper to process tree block while walking down the tree. * * when wc->stage == UPDATE_BACKREF, this function updates * back refs for pointers in the block. * * NOTE: return value 1 means we should stop walking down. */ static noinline int walk_down_proc(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc, int lookup_info) { int level = wc->level; struct extent_buffer *eb = path->nodes[level]; u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF; int ret; if (wc->stage == UPDATE_BACKREF && btrfs_header_owner(eb) != root->root_key.objectid) return 1; /* * when reference count of tree block is 1, it won't increase * again. once full backref flag is set, we never clear it. */ if (lookup_info && ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) || (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) { BUG_ON(!path->locks[level]); ret = btrfs_lookup_extent_info(trans, root, eb->start, level, 1, &wc->refs[level], &wc->flags[level]); BUG_ON(ret == -ENOMEM); if (ret) return ret; BUG_ON(wc->refs[level] == 0); } if (wc->stage == DROP_REFERENCE) { if (wc->refs[level] > 1) return 1; if (path->locks[level] && !wc->keep_locks) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; } return 0; } /* wc->stage == UPDATE_BACKREF */ if (!(wc->flags[level] & flag)) { BUG_ON(!path->locks[level]); ret = btrfs_inc_ref(trans, root, eb, 1); BUG_ON(ret); /* -ENOMEM */ ret = btrfs_dec_ref(trans, root, eb, 0); BUG_ON(ret); /* -ENOMEM */ ret = btrfs_set_disk_extent_flags(trans, root, eb->start, eb->len, flag, btrfs_header_level(eb), 0); BUG_ON(ret); /* -ENOMEM */ wc->flags[level] |= flag; } /* * the block is shared by multiple trees, so it's not good to * keep the tree lock */ if (path->locks[level] && level > 0) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; } return 0; } /* * helper to process tree block pointer. * * when wc->stage == DROP_REFERENCE, this function checks * reference count of the block pointed to. if the block * is shared and we need update back refs for the subtree * rooted at the block, this function changes wc->stage to * UPDATE_BACKREF. if the block is shared and there is no * need to update back, this function drops the reference * to the block. * * NOTE: return value 1 means we should stop walking down. */ static noinline int do_walk_down(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc, int *lookup_info) { u64 bytenr; u64 generation; u64 parent; u32 blocksize; struct btrfs_key key; struct extent_buffer *next; int level = wc->level; int reada = 0; int ret = 0; bool need_account = false; generation = btrfs_node_ptr_generation(path->nodes[level], path->slots[level]); /* * if the lower level block was created before the snapshot * was created, we know there is no need to update back refs * for the subtree */ if (wc->stage == UPDATE_BACKREF && generation <= root->root_key.offset) { *lookup_info = 1; return 1; } bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]); blocksize = root->nodesize; next = btrfs_find_tree_block(root->fs_info, bytenr); if (!next) { next = btrfs_find_create_tree_block(root, bytenr); if (!next) return -ENOMEM; btrfs_set_buffer_lockdep_class(root->root_key.objectid, next, level - 1); reada = 1; } btrfs_tree_lock(next); btrfs_set_lock_blocking(next); ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1, &wc->refs[level - 1], &wc->flags[level - 1]); if (ret < 0) { btrfs_tree_unlock(next); return ret; } if (unlikely(wc->refs[level - 1] == 0)) { btrfs_err(root->fs_info, "Missing references."); BUG(); } *lookup_info = 0; if (wc->stage == DROP_REFERENCE) { if (wc->refs[level - 1] > 1) { need_account = true; if (level == 1 && (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) goto skip; if (!wc->update_ref || generation <= root->root_key.offset) goto skip; btrfs_node_key_to_cpu(path->nodes[level], &key, path->slots[level]); ret = btrfs_comp_cpu_keys(&key, &wc->update_progress); if (ret < 0) goto skip; wc->stage = UPDATE_BACKREF; wc->shared_level = level - 1; } } else { if (level == 1 && (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) goto skip; } if (!btrfs_buffer_uptodate(next, generation, 0)) { btrfs_tree_unlock(next); free_extent_buffer(next); next = NULL; *lookup_info = 1; } if (!next) { if (reada && level == 1) reada_walk_down(trans, root, wc, path); next = read_tree_block(root, bytenr, generation); if (IS_ERR(next)) { return PTR_ERR(next); } else if (!extent_buffer_uptodate(next)) { free_extent_buffer(next); return -EIO; } btrfs_tree_lock(next); btrfs_set_lock_blocking(next); } level--; BUG_ON(level != btrfs_header_level(next)); path->nodes[level] = next; path->slots[level] = 0; path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; wc->level = level; if (wc->level == 1) wc->reada_slot = 0; return 0; skip: wc->refs[level - 1] = 0; wc->flags[level - 1] = 0; if (wc->stage == DROP_REFERENCE) { if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) { parent = path->nodes[level]->start; } else { BUG_ON(root->root_key.objectid != btrfs_header_owner(path->nodes[level])); parent = 0; } if (need_account) { ret = account_shared_subtree(trans, root, next, generation, level - 1); if (ret) { btrfs_err_rl(root->fs_info, "Error " "%d accounting shared subtree. Quota " "is out of sync, rescan required.", ret); } } ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent, root->root_key.objectid, level - 1, 0, 0); BUG_ON(ret); /* -ENOMEM */ } btrfs_tree_unlock(next); free_extent_buffer(next); *lookup_info = 1; return 1; } /* * helper to process tree block while walking up the tree. * * when wc->stage == DROP_REFERENCE, this function drops * reference count on the block. * * when wc->stage == UPDATE_BACKREF, this function changes * wc->stage back to DROP_REFERENCE if we changed wc->stage * to UPDATE_BACKREF previously while processing the block. * * NOTE: return value 1 means we should stop walking up. */ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc) { int ret; int level = wc->level; struct extent_buffer *eb = path->nodes[level]; u64 parent = 0; if (wc->stage == UPDATE_BACKREF) { BUG_ON(wc->shared_level < level); if (level < wc->shared_level) goto out; ret = find_next_key(path, level + 1, &wc->update_progress); if (ret > 0) wc->update_ref = 0; wc->stage = DROP_REFERENCE; wc->shared_level = -1; path->slots[level] = 0; /* * check reference count again if the block isn't locked. * we should start walking down the tree again if reference * count is one. */ if (!path->locks[level]) { BUG_ON(level == 0); btrfs_tree_lock(eb); btrfs_set_lock_blocking(eb); path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; ret = btrfs_lookup_extent_info(trans, root, eb->start, level, 1, &wc->refs[level], &wc->flags[level]); if (ret < 0) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; return ret; } BUG_ON(wc->refs[level] == 0); if (wc->refs[level] == 1) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; return 1; } } } /* wc->stage == DROP_REFERENCE */ BUG_ON(wc->refs[level] > 1 && !path->locks[level]); if (wc->refs[level] == 1) { if (level == 0) { if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) ret = btrfs_dec_ref(trans, root, eb, 1); else ret = btrfs_dec_ref(trans, root, eb, 0); BUG_ON(ret); /* -ENOMEM */ ret = account_leaf_items(trans, root, eb); if (ret) { btrfs_err_rl(root->fs_info, "error " "%d accounting leaf items. Quota " "is out of sync, rescan required.", ret); } } /* make block locked assertion in clean_tree_block happy */ if (!path->locks[level] && btrfs_header_generation(eb) == trans->transid) { btrfs_tree_lock(eb); btrfs_set_lock_blocking(eb); path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; } clean_tree_block(trans, root->fs_info, eb); } if (eb == root->node) { if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) parent = eb->start; else BUG_ON(root->root_key.objectid != btrfs_header_owner(eb)); } else { if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF) parent = path->nodes[level + 1]->start; else BUG_ON(root->root_key.objectid != btrfs_header_owner(path->nodes[level + 1])); } btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1); out: wc->refs[level] = 0; wc->flags[level] = 0; return 0; } static noinline int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc) { int level = wc->level; int lookup_info = 1; int ret; while (level >= 0) { ret = walk_down_proc(trans, root, path, wc, lookup_info); if (ret > 0) break; if (level == 0) break; if (path->slots[level] >= btrfs_header_nritems(path->nodes[level])) break; ret = do_walk_down(trans, root, path, wc, &lookup_info); if (ret > 0) { path->slots[level]++; continue; } else if (ret < 0) return ret; level = wc->level; } return 0; } static noinline int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc, int max_level) { int level = wc->level; int ret; path->slots[level] = btrfs_header_nritems(path->nodes[level]); while (level < max_level && path->nodes[level]) { wc->level = level; if (path->slots[level] + 1 < btrfs_header_nritems(path->nodes[level])) { path->slots[level]++; return 0; } else { ret = walk_up_proc(trans, root, path, wc); if (ret > 0) return 0; if (path->locks[level]) { btrfs_tree_unlock_rw(path->nodes[level], path->locks[level]); path->locks[level] = 0; } free_extent_buffer(path->nodes[level]); path->nodes[level] = NULL; level++; } } return 1; } /* * drop a subvolume tree. * * this function traverses the tree freeing any blocks that only * referenced by the tree. * * when a shared tree block is found. this function decreases its * reference count by one. if update_ref is true, this function * also make sure backrefs for the shared block and all lower level * blocks are properly updated. * * If called with for_reloc == 0, may exit early with -EAGAIN */ int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, int update_ref, int for_reloc) { struct btrfs_path *path; struct btrfs_trans_handle *trans; struct btrfs_root *tree_root = root->fs_info->tree_root; struct btrfs_root_item *root_item = &root->root_item; struct walk_control *wc; struct btrfs_key key; int err = 0; int ret; int level; bool root_dropped = false; btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid); path = btrfs_alloc_path(); if (!path) { err = -ENOMEM; goto out; } wc = kzalloc(sizeof(*wc), GFP_NOFS); if (!wc) { btrfs_free_path(path); err = -ENOMEM; goto out; } trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) { err = PTR_ERR(trans); goto out_free; } if (block_rsv) trans->block_rsv = block_rsv; if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { level = btrfs_header_level(root->node); path->nodes[level] = btrfs_lock_root_node(root); btrfs_set_lock_blocking(path->nodes[level]); path->slots[level] = 0; path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; memset(&wc->update_progress, 0, sizeof(wc->update_progress)); } else { btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); memcpy(&wc->update_progress, &key, sizeof(wc->update_progress)); level = root_item->drop_level; BUG_ON(level == 0); path->lowest_level = level; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); path->lowest_level = 0; if (ret < 0) { err = ret; goto out_end_trans; } WARN_ON(ret > 0); /* * unlock our path, this is safe because only this * function is allowed to delete this snapshot */ btrfs_unlock_up_safe(path, 0); level = btrfs_header_level(root->node); while (1) { btrfs_tree_lock(path->nodes[level]); btrfs_set_lock_blocking(path->nodes[level]); path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; ret = btrfs_lookup_extent_info(trans, root, path->nodes[level]->start, level, 1, &wc->refs[level], &wc->flags[level]); if (ret < 0) { err = ret; goto out_end_trans; } BUG_ON(wc->refs[level] == 0); if (level == root_item->drop_level) break; btrfs_tree_unlock(path->nodes[level]); path->locks[level] = 0; WARN_ON(wc->refs[level] != 1); level--; } } wc->level = level; wc->shared_level = -1; wc->stage = DROP_REFERENCE; wc->update_ref = update_ref; wc->keep_locks = 0; wc->for_reloc = for_reloc; wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root); while (1) { ret = walk_down_tree(trans, root, path, wc); if (ret < 0) { err = ret; break; } ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL); if (ret < 0) { err = ret; break; } if (ret > 0) { BUG_ON(wc->stage != DROP_REFERENCE); break; } if (wc->stage == DROP_REFERENCE) { level = wc->level; btrfs_node_key(path->nodes[level], &root_item->drop_progress, path->slots[level]); root_item->drop_level = level; } BUG_ON(wc->level == 0); if (btrfs_should_end_transaction(trans, tree_root) || (!for_reloc && btrfs_need_cleaner_sleep(root))) { ret = btrfs_update_root(trans, tree_root, &root->root_key, root_item); if (ret) { btrfs_abort_transaction(trans, tree_root, ret); err = ret; goto out_end_trans; } btrfs_end_transaction_throttle(trans, tree_root); if (!for_reloc && btrfs_need_cleaner_sleep(root)) { pr_debug("BTRFS: drop snapshot early exit\n"); err = -EAGAIN; goto out_free; } trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) { err = PTR_ERR(trans); goto out_free; } if (block_rsv) trans->block_rsv = block_rsv; } } btrfs_release_path(path); if (err) goto out_end_trans; ret = btrfs_del_root(trans, tree_root, &root->root_key); if (ret) { btrfs_abort_transaction(trans, tree_root, ret); goto out_end_trans; } if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { ret = btrfs_find_root(tree_root, &root->root_key, path, NULL, NULL); if (ret < 0) { btrfs_abort_transaction(trans, tree_root, ret); err = ret; goto out_end_trans; } else if (ret > 0) { /* if we fail to delete the orphan item this time * around, it'll get picked up the next time. * * The most common failure here is just -ENOENT. */ btrfs_del_orphan_item(trans, tree_root, root->root_key.objectid); } } if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) { btrfs_add_dropped_root(trans, root); } else { free_extent_buffer(root->node); free_extent_buffer(root->commit_root); btrfs_put_fs_root(root); } root_dropped = true; out_end_trans: btrfs_end_transaction_throttle(trans, tree_root); out_free: kfree(wc); btrfs_free_path(path); out: /* * So if we need to stop dropping the snapshot for whatever reason we * need to make sure to add it back to the dead root list so that we * keep trying to do the work later. This also cleans up roots if we * don't have it in the radix (like when we recover after a power fail * or unmount) so we don't leak memory. */ if (!for_reloc && root_dropped == false) btrfs_add_dead_root(root); if (err && err != -EAGAIN) btrfs_std_error(root->fs_info, err, NULL); return err; } /* * drop subtree rooted at tree block 'node'. * * NOTE: this function will unlock and release tree block 'node' * only used by relocation code */ int btrfs_drop_subtree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *node, struct extent_buffer *parent) { struct btrfs_path *path; struct walk_control *wc; int level; int parent_level; int ret = 0; int wret; BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); path = btrfs_alloc_path(); if (!path) return -ENOMEM; wc = kzalloc(sizeof(*wc), GFP_NOFS); if (!wc) { btrfs_free_path(path); return -ENOMEM; } btrfs_assert_tree_locked(parent); parent_level = btrfs_header_level(parent); extent_buffer_get(parent); path->nodes[parent_level] = parent; path->slots[parent_level] = btrfs_header_nritems(parent); btrfs_assert_tree_locked(node); level = btrfs_header_level(node); path->nodes[level] = node; path->slots[level] = 0; path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; wc->refs[parent_level] = 1; wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF; wc->level = level; wc->shared_level = -1; wc->stage = DROP_REFERENCE; wc->update_ref = 0; wc->keep_locks = 1; wc->for_reloc = 1; wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root); while (1) { wret = walk_down_tree(trans, root, path, wc); if (wret < 0) { ret = wret; break; } wret = walk_up_tree(trans, root, path, wc, parent_level); if (wret < 0) ret = wret; if (wret != 0) break; } kfree(wc); btrfs_free_path(path); return ret; } static u64 update_block_group_flags(struct btrfs_root *root, u64 flags) { u64 num_devices; u64 stripped; /* * if restripe for this chunk_type is on pick target profile and * return, otherwise do the usual balance */ stripped = get_restripe_target(root->fs_info, flags); if (stripped) return extended_to_chunk(stripped); num_devices = root->fs_info->fs_devices->rw_devices; stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10; if (num_devices == 1) { stripped |= BTRFS_BLOCK_GROUP_DUP; stripped = flags & ~stripped; /* turn raid0 into single device chunks */ if (flags & BTRFS_BLOCK_GROUP_RAID0) return stripped; /* turn mirroring into duplication */ if (flags & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) return stripped | BTRFS_BLOCK_GROUP_DUP; } else { /* they already had raid on here, just return */ if (flags & stripped) return flags; stripped |= BTRFS_BLOCK_GROUP_DUP; stripped = flags & ~stripped; /* switch duplicated blocks with raid1 */ if (flags & BTRFS_BLOCK_GROUP_DUP) return stripped | BTRFS_BLOCK_GROUP_RAID1; /* this is drive concat, leave it alone */ } return flags; } static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force) { struct btrfs_space_info *sinfo = cache->space_info; u64 num_bytes; u64 min_allocable_bytes; int ret = -ENOSPC; /* * We need some metadata space and system metadata space for * allocating chunks in some corner cases until we force to set * it to be readonly. */ if ((sinfo->flags & (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) && !force) min_allocable_bytes = 1 * 1024 * 1024; else min_allocable_bytes = 0; spin_lock(&sinfo->lock); spin_lock(&cache->lock); if (cache->ro) { cache->ro++; ret = 0; goto out; } num_bytes = cache->key.offset - cache->reserved - cache->pinned - cache->bytes_super - btrfs_block_group_used(&cache->item); if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned + sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes + min_allocable_bytes <= sinfo->total_bytes) { sinfo->bytes_readonly += num_bytes; cache->ro++; list_add_tail(&cache->ro_list, &sinfo->ro_bgs); ret = 0; } out: spin_unlock(&cache->lock); spin_unlock(&sinfo->lock); return ret; } int btrfs_inc_block_group_ro(struct btrfs_root *root, struct btrfs_block_group_cache *cache) { struct btrfs_trans_handle *trans; u64 alloc_flags; int ret; again: trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return PTR_ERR(trans); /* * we're not allowed to set block groups readonly after the dirty * block groups cache has started writing. If it already started, * back off and let this transaction commit */ mutex_lock(&root->fs_info->ro_block_group_mutex); if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) { u64 transid = trans->transid; mutex_unlock(&root->fs_info->ro_block_group_mutex); btrfs_end_transaction(trans, root); ret = btrfs_wait_for_commit(root, transid); if (ret) return ret; goto again; } /* * if we are changing raid levels, try to allocate a corresponding * block group with the new raid level. */ alloc_flags = update_block_group_flags(root, cache->flags); if (alloc_flags != cache->flags) { ret = do_chunk_alloc(trans, root, alloc_flags, CHUNK_ALLOC_FORCE); /* * ENOSPC is allowed here, we may have enough space * already allocated at the new raid level to * carry on */ if (ret == -ENOSPC) ret = 0; if (ret < 0) goto out; } ret = inc_block_group_ro(cache, 0); if (!ret) goto out; alloc_flags = get_alloc_profile(root, cache->space_info->flags); ret = do_chunk_alloc(trans, root, alloc_flags, CHUNK_ALLOC_FORCE); if (ret < 0) goto out; ret = inc_block_group_ro(cache, 0); out: if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) { alloc_flags = update_block_group_flags(root, cache->flags); lock_chunks(root->fs_info->chunk_root); check_system_chunk(trans, root, alloc_flags); unlock_chunks(root->fs_info->chunk_root); } mutex_unlock(&root->fs_info->ro_block_group_mutex); btrfs_end_transaction(trans, root); return ret; } int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 type) { u64 alloc_flags = get_alloc_profile(root, type); return do_chunk_alloc(trans, root, alloc_flags, CHUNK_ALLOC_FORCE); } /* * helper to account the unused space of all the readonly block group in the * space_info. takes mirrors into account. */ u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo) { struct btrfs_block_group_cache *block_group; u64 free_bytes = 0; int factor; /* It's df, we don't care if it's racey */ if (list_empty(&sinfo->ro_bgs)) return 0; spin_lock(&sinfo->lock); list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) { spin_lock(&block_group->lock); if (!block_group->ro) { spin_unlock(&block_group->lock); continue; } if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10 | BTRFS_BLOCK_GROUP_DUP)) factor = 2; else factor = 1; free_bytes += (block_group->key.offset - btrfs_block_group_used(&block_group->item)) * factor; spin_unlock(&block_group->lock); } spin_unlock(&sinfo->lock); return free_bytes; } void btrfs_dec_block_group_ro(struct btrfs_root *root, struct btrfs_block_group_cache *cache) { struct btrfs_space_info *sinfo = cache->space_info; u64 num_bytes; BUG_ON(!cache->ro); spin_lock(&sinfo->lock); spin_lock(&cache->lock); if (!--cache->ro) { num_bytes = cache->key.offset - cache->reserved - cache->pinned - cache->bytes_super - btrfs_block_group_used(&cache->item); sinfo->bytes_readonly -= num_bytes; list_del_init(&cache->ro_list); } spin_unlock(&cache->lock); spin_unlock(&sinfo->lock); } /* * checks to see if its even possible to relocate this block group. * * @return - -1 if it's not a good idea to relocate this block group, 0 if its * ok to go ahead and try. */ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr) { struct btrfs_block_group_cache *block_group; struct btrfs_space_info *space_info; struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices; struct btrfs_device *device; struct btrfs_trans_handle *trans; u64 min_free; u64 dev_min = 1; u64 dev_nr = 0; u64 target; int index; int full = 0; int ret = 0; block_group = btrfs_lookup_block_group(root->fs_info, bytenr); /* odd, couldn't find the block group, leave it alone */ if (!block_group) return -1; min_free = btrfs_block_group_used(&block_group->item); /* no bytes used, we're good */ if (!min_free) goto out; space_info = block_group->space_info; spin_lock(&space_info->lock); full = space_info->full; /* * if this is the last block group we have in this space, we can't * relocate it unless we're able to allocate a new chunk below. * * Otherwise, we need to make sure we have room in the space to handle * all of the extents from this block group. If we can, we're good */ if ((space_info->total_bytes != block_group->key.offset) && (space_info->bytes_used + space_info->bytes_reserved + space_info->bytes_pinned + space_info->bytes_readonly + min_free < space_info->total_bytes)) { spin_unlock(&space_info->lock); goto out; } spin_unlock(&space_info->lock); /* * ok we don't have enough space, but maybe we have free space on our * devices to allocate new chunks for relocation, so loop through our * alloc devices and guess if we have enough space. if this block * group is going to be restriped, run checks against the target * profile instead of the current one. */ ret = -1; /* * index: * 0: raid10 * 1: raid1 * 2: dup * 3: raid0 * 4: single */ target = get_restripe_target(root->fs_info, block_group->flags); if (target) { index = __get_raid_index(extended_to_chunk(target)); } else { /* * this is just a balance, so if we were marked as full * we know there is no space for a new chunk */ if (full) goto out; index = get_block_group_index(block_group); } if (index == BTRFS_RAID_RAID10) { dev_min = 4; /* Divide by 2 */ min_free >>= 1; } else if (index == BTRFS_RAID_RAID1) { dev_min = 2; } else if (index == BTRFS_RAID_DUP) { /* Multiply by 2 */ min_free <<= 1; } else if (index == BTRFS_RAID_RAID0) { dev_min = fs_devices->rw_devices; min_free = div64_u64(min_free, dev_min); } /* We need to do this so that we can look at pending chunks */ trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); goto out; } mutex_lock(&root->fs_info->chunk_mutex); list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { u64 dev_offset; /* * check to make sure we can actually find a chunk with enough * space to fit our block group in. */ if (device->total_bytes > device->bytes_used + min_free && !device->is_tgtdev_for_dev_replace) { ret = find_free_dev_extent(trans, device, min_free, &dev_offset, NULL); if (!ret) dev_nr++; if (dev_nr >= dev_min) break; ret = -1; } } mutex_unlock(&root->fs_info->chunk_mutex); btrfs_end_transaction(trans, root); out: btrfs_put_block_group(block_group); return ret; } static int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key) { int ret = 0; struct btrfs_key found_key; struct extent_buffer *leaf; int slot; ret = btrfs_search_slot(NULL, root, key, path, 0, 0); if (ret < 0) goto out; while (1) { slot = path->slots[0]; leaf = path->nodes[0]; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret == 0) continue; if (ret < 0) goto out; break; } btrfs_item_key_to_cpu(leaf, &found_key, slot); if (found_key.objectid >= key->objectid && found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { ret = 0; goto out; } path->slots[0]++; } out: return ret; } void btrfs_put_block_group_cache(struct btrfs_fs_info *info) { struct btrfs_block_group_cache *block_group; u64 last = 0; while (1) { struct inode *inode; block_group = btrfs_lookup_first_block_group(info, last); while (block_group) { spin_lock(&block_group->lock); if (block_group->iref) break; spin_unlock(&block_group->lock); block_group = next_block_group(info->tree_root, block_group); } if (!block_group) { if (last == 0) break; last = 0; continue; } inode = block_group->inode; block_group->iref = 0; block_group->inode = NULL; spin_unlock(&block_group->lock); iput(inode); last = block_group->key.objectid + block_group->key.offset; btrfs_put_block_group(block_group); } } int btrfs_free_block_groups(struct btrfs_fs_info *info) { struct btrfs_block_group_cache *block_group; struct btrfs_space_info *space_info; struct btrfs_caching_control *caching_ctl; struct rb_node *n; down_write(&info->commit_root_sem); while (!list_empty(&info->caching_block_groups)) { caching_ctl = list_entry(info->caching_block_groups.next, struct btrfs_caching_control, list); list_del(&caching_ctl->list); put_caching_control(caching_ctl); } up_write(&info->commit_root_sem); spin_lock(&info->unused_bgs_lock); while (!list_empty(&info->unused_bgs)) { block_group = list_first_entry(&info->unused_bgs, struct btrfs_block_group_cache, bg_list); list_del_init(&block_group->bg_list); btrfs_put_block_group(block_group); } spin_unlock(&info->unused_bgs_lock); spin_lock(&info->block_group_cache_lock); while ((n = rb_last(&info->block_group_cache_tree)) != NULL) { block_group = rb_entry(n, struct btrfs_block_group_cache, cache_node); rb_erase(&block_group->cache_node, &info->block_group_cache_tree); RB_CLEAR_NODE(&block_group->cache_node); spin_unlock(&info->block_group_cache_lock); down_write(&block_group->space_info->groups_sem); list_del(&block_group->list); up_write(&block_group->space_info->groups_sem); if (block_group->cached == BTRFS_CACHE_STARTED) wait_block_group_cache_done(block_group); /* * We haven't cached this block group, which means we could * possibly have excluded extents on this block group. */ if (block_group->cached == BTRFS_CACHE_NO || block_group->cached == BTRFS_CACHE_ERROR) free_excluded_extents(info->extent_root, block_group); btrfs_remove_free_space_cache(block_group); btrfs_put_block_group(block_group); spin_lock(&info->block_group_cache_lock); } spin_unlock(&info->block_group_cache_lock); /* now that all the block groups are freed, go through and * free all the space_info structs. This is only called during * the final stages of unmount, and so we know nobody is * using them. We call synchronize_rcu() once before we start, * just to be on the safe side. */ synchronize_rcu(); release_global_block_rsv(info); while (!list_empty(&info->space_info)) { int i; space_info = list_entry(info->space_info.next, struct btrfs_space_info, list); if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) { if (WARN_ON(space_info->bytes_pinned > 0 || space_info->bytes_reserved > 0 || space_info->bytes_may_use > 0)) { dump_space_info(space_info, 0, 0); } } list_del(&space_info->list); for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) { struct kobject *kobj; kobj = space_info->block_group_kobjs[i]; space_info->block_group_kobjs[i] = NULL; if (kobj) { kobject_del(kobj); kobject_put(kobj); } } kobject_del(&space_info->kobj); kobject_put(&space_info->kobj); } return 0; } static void __link_block_group(struct btrfs_space_info *space_info, struct btrfs_block_group_cache *cache) { int index = get_block_group_index(cache); bool first = false; down_write(&space_info->groups_sem); if (list_empty(&space_info->block_groups[index])) first = true; list_add_tail(&cache->list, &space_info->block_groups[index]); up_write(&space_info->groups_sem); if (first) { struct raid_kobject *rkobj; int ret; rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS); if (!rkobj) goto out_err; rkobj->raid_type = index; kobject_init(&rkobj->kobj, &btrfs_raid_ktype); ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s", get_raid_name(index)); if (ret) { kobject_put(&rkobj->kobj); goto out_err; } space_info->block_group_kobjs[index] = &rkobj->kobj; } return; out_err: pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n"); } static struct btrfs_block_group_cache * btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size) { struct btrfs_block_group_cache *cache; cache = kzalloc(sizeof(*cache), GFP_NOFS); if (!cache) return NULL; cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl), GFP_NOFS); if (!cache->free_space_ctl) { kfree(cache); return NULL; } cache->key.objectid = start; cache->key.offset = size; cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; cache->sectorsize = root->sectorsize; cache->fs_info = root->fs_info; cache->full_stripe_len = btrfs_full_stripe_len(root, &root->fs_info->mapping_tree, start); atomic_set(&cache->count, 1); spin_lock_init(&cache->lock); init_rwsem(&cache->data_rwsem); INIT_LIST_HEAD(&cache->list); INIT_LIST_HEAD(&cache->cluster_list); INIT_LIST_HEAD(&cache->bg_list); INIT_LIST_HEAD(&cache->ro_list); INIT_LIST_HEAD(&cache->dirty_list); INIT_LIST_HEAD(&cache->io_list); btrfs_init_free_space_ctl(cache); atomic_set(&cache->trimming, 0); return cache; } int btrfs_read_block_groups(struct btrfs_root *root) { struct btrfs_path *path; int ret; struct btrfs_block_group_cache *cache; struct btrfs_fs_info *info = root->fs_info; struct btrfs_space_info *space_info; struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *leaf; int need_clear = 0; u64 cache_gen; root = info->extent_root; key.objectid = 0; key.offset = 0; key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = 1; cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); if (btrfs_test_opt(root, SPACE_CACHE) && btrfs_super_generation(root->fs_info->super_copy) != cache_gen) need_clear = 1; if (btrfs_test_opt(root, CLEAR_CACHE)) need_clear = 1; while (1) { ret = find_first_block_group(root, path, &key); if (ret > 0) break; if (ret != 0) goto error; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); cache = btrfs_create_block_group_cache(root, found_key.objectid, found_key.offset); if (!cache) { ret = -ENOMEM; goto error; } if (need_clear) { /* * When we mount with old space cache, we need to * set BTRFS_DC_CLEAR and set dirty flag. * * a) Setting 'BTRFS_DC_CLEAR' makes sure that we * truncate the old free space cache inode and * setup a new one. * b) Setting 'dirty flag' makes sure that we flush * the new space cache info onto disk. */ if (btrfs_test_opt(root, SPACE_CACHE)) cache->disk_cache_state = BTRFS_DC_CLEAR; } read_extent_buffer(leaf, &cache->item, btrfs_item_ptr_offset(leaf, path->slots[0]), sizeof(cache->item)); cache->flags = btrfs_block_group_flags(&cache->item); key.objectid = found_key.objectid + found_key.offset; btrfs_release_path(path); /* * We need to exclude the super stripes now so that the space * info has super bytes accounted for, otherwise we'll think * we have more space than we actually do. */ ret = exclude_super_stripes(root, cache); if (ret) { /* * We may have excluded something, so call this just in * case. */ free_excluded_extents(root, cache); btrfs_put_block_group(cache); goto error; } /* * check for two cases, either we are full, and therefore * don't need to bother with the caching work since we won't * find any space, or we are empty, and we can just add all * the space in and be done with it. This saves us _alot_ of * time, particularly in the full case. */ if (found_key.offset == btrfs_block_group_used(&cache->item)) { cache->last_byte_to_unpin = (u64)-1; cache->cached = BTRFS_CACHE_FINISHED; free_excluded_extents(root, cache); } else if (btrfs_block_group_used(&cache->item) == 0) { cache->last_byte_to_unpin = (u64)-1; cache->cached = BTRFS_CACHE_FINISHED; add_new_free_space(cache, root->fs_info, found_key.objectid, found_key.objectid + found_key.offset); free_excluded_extents(root, cache); } ret = btrfs_add_block_group_cache(root->fs_info, cache); if (ret) { btrfs_remove_free_space_cache(cache); btrfs_put_block_group(cache); goto error; } ret = update_space_info(info, cache->flags, found_key.offset, btrfs_block_group_used(&cache->item), &space_info); if (ret) { btrfs_remove_free_space_cache(cache); spin_lock(&info->block_group_cache_lock); rb_erase(&cache->cache_node, &info->block_group_cache_tree); RB_CLEAR_NODE(&cache->cache_node); spin_unlock(&info->block_group_cache_lock); btrfs_put_block_group(cache); goto error; } cache->space_info = space_info; spin_lock(&cache->space_info->lock); cache->space_info->bytes_readonly += cache->bytes_super; spin_unlock(&cache->space_info->lock); __link_block_group(space_info, cache); set_avail_alloc_bits(root->fs_info, cache->flags); if (btrfs_chunk_readonly(root, cache->key.objectid)) { inc_block_group_ro(cache, 1); } else if (btrfs_block_group_used(&cache->item) == 0) { spin_lock(&info->unused_bgs_lock); /* Should always be true but just in case. */ if (list_empty(&cache->bg_list)) { btrfs_get_block_group(cache); list_add_tail(&cache->bg_list, &info->unused_bgs); } spin_unlock(&info->unused_bgs_lock); } } list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) { if (!(get_alloc_profile(root, space_info->flags) & (BTRFS_BLOCK_GROUP_RAID10 | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_DUP))) continue; /* * avoid allocating from un-mirrored block group if there are * mirrored block groups. */ list_for_each_entry(cache, &space_info->block_groups[BTRFS_RAID_RAID0], list) inc_block_group_ro(cache, 1); list_for_each_entry(cache, &space_info->block_groups[BTRFS_RAID_SINGLE], list) inc_block_group_ro(cache, 1); } init_global_block_rsv(info); ret = 0; error: btrfs_free_path(path); return ret; } void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_block_group_cache *block_group, *tmp; struct btrfs_root *extent_root = root->fs_info->extent_root; struct btrfs_block_group_item item; struct btrfs_key key; int ret = 0; bool can_flush_pending_bgs = trans->can_flush_pending_bgs; trans->can_flush_pending_bgs = false; list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { if (ret) goto next; spin_lock(&block_group->lock); memcpy(&item, &block_group->item, sizeof(item)); memcpy(&key, &block_group->key, sizeof(key)); spin_unlock(&block_group->lock); ret = btrfs_insert_item(trans, extent_root, &key, &item, sizeof(item)); if (ret) btrfs_abort_transaction(trans, extent_root, ret); ret = btrfs_finish_chunk_alloc(trans, extent_root, key.objectid, key.offset); if (ret) btrfs_abort_transaction(trans, extent_root, ret); next: list_del_init(&block_group->bg_list); } trans->can_flush_pending_bgs = can_flush_pending_bgs; } int btrfs_make_block_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytes_used, u64 type, u64 chunk_objectid, u64 chunk_offset, u64 size) { int ret; struct btrfs_root *extent_root; struct btrfs_block_group_cache *cache; extent_root = root->fs_info->extent_root; btrfs_set_log_full_commit(root->fs_info, trans); cache = btrfs_create_block_group_cache(root, chunk_offset, size); if (!cache) return -ENOMEM; btrfs_set_block_group_used(&cache->item, bytes_used); btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid); btrfs_set_block_group_flags(&cache->item, type); cache->flags = type; cache->last_byte_to_unpin = (u64)-1; cache->cached = BTRFS_CACHE_FINISHED; ret = exclude_super_stripes(root, cache); if (ret) { /* * We may have excluded something, so call this just in * case. */ free_excluded_extents(root, cache); btrfs_put_block_group(cache); return ret; } add_new_free_space(cache, root->fs_info, chunk_offset, chunk_offset + size); free_excluded_extents(root, cache); #ifdef CONFIG_BTRFS_DEBUG if (btrfs_should_fragment_free_space(root, cache)) { u64 new_bytes_used = size - bytes_used; bytes_used += new_bytes_used >> 1; fragment_free_space(root, cache); } #endif /* * Call to ensure the corresponding space_info object is created and * assigned to our block group, but don't update its counters just yet. * We want our bg to be added to the rbtree with its ->space_info set. */ ret = update_space_info(root->fs_info, cache->flags, 0, 0, &cache->space_info); if (ret) { btrfs_remove_free_space_cache(cache); btrfs_put_block_group(cache); return ret; } ret = btrfs_add_block_group_cache(root->fs_info, cache); if (ret) { btrfs_remove_free_space_cache(cache); btrfs_put_block_group(cache); return ret; } /* * Now that our block group has its ->space_info set and is inserted in * the rbtree, update the space info's counters. */ ret = update_space_info(root->fs_info, cache->flags, size, bytes_used, &cache->space_info); if (ret) { btrfs_remove_free_space_cache(cache); spin_lock(&root->fs_info->block_group_cache_lock); rb_erase(&cache->cache_node, &root->fs_info->block_group_cache_tree); RB_CLEAR_NODE(&cache->cache_node); spin_unlock(&root->fs_info->block_group_cache_lock); btrfs_put_block_group(cache); return ret; } update_global_block_rsv(root->fs_info); spin_lock(&cache->space_info->lock); cache->space_info->bytes_readonly += cache->bytes_super; spin_unlock(&cache->space_info->lock); __link_block_group(cache->space_info, cache); list_add_tail(&cache->bg_list, &trans->new_bgs); set_avail_alloc_bits(extent_root->fs_info, type); return 0; } static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags) { u64 extra_flags = chunk_to_extended(flags) & BTRFS_EXTENDED_PROFILE_MASK; write_seqlock(&fs_info->profiles_lock); if (flags & BTRFS_BLOCK_GROUP_DATA) fs_info->avail_data_alloc_bits &= ~extra_flags; if (flags & BTRFS_BLOCK_GROUP_METADATA) fs_info->avail_metadata_alloc_bits &= ~extra_flags; if (flags & BTRFS_BLOCK_GROUP_SYSTEM) fs_info->avail_system_alloc_bits &= ~extra_flags; write_sequnlock(&fs_info->profiles_lock); } int btrfs_remove_block_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 group_start, struct extent_map *em) { struct btrfs_path *path; struct btrfs_block_group_cache *block_group; struct btrfs_free_cluster *cluster; struct btrfs_root *tree_root = root->fs_info->tree_root; struct btrfs_key key; struct inode *inode; struct kobject *kobj = NULL; int ret; int index; int factor; struct btrfs_caching_control *caching_ctl = NULL; bool remove_em; root = root->fs_info->extent_root; block_group = btrfs_lookup_block_group(root->fs_info, group_start); BUG_ON(!block_group); BUG_ON(!block_group->ro); /* * Free the reserved super bytes from this block group before * remove it. */ free_excluded_extents(root, block_group); memcpy(&key, &block_group->key, sizeof(key)); index = get_block_group_index(block_group); if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) factor = 2; else factor = 1; /* make sure this block group isn't part of an allocation cluster */ cluster = &root->fs_info->data_alloc_cluster; spin_lock(&cluster->refill_lock); btrfs_return_cluster_to_free_space(block_group, cluster); spin_unlock(&cluster->refill_lock); /* * make sure this block group isn't part of a metadata * allocation cluster */ cluster = &root->fs_info->meta_alloc_cluster; spin_lock(&cluster->refill_lock); btrfs_return_cluster_to_free_space(block_group, cluster); spin_unlock(&cluster->refill_lock); path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } /* * get the inode first so any iput calls done for the io_list * aren't the final iput (no unlinks allowed now) */ inode = lookup_free_space_inode(tree_root, block_group, path); mutex_lock(&trans->transaction->cache_write_mutex); /* * make sure our free spache cache IO is done before remove the * free space inode */ spin_lock(&trans->transaction->dirty_bgs_lock); if (!list_empty(&block_group->io_list)) { list_del_init(&block_group->io_list); WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode); spin_unlock(&trans->transaction->dirty_bgs_lock); btrfs_wait_cache_io(root, trans, block_group, &block_group->io_ctl, path, block_group->key.objectid); btrfs_put_block_group(block_group); spin_lock(&trans->transaction->dirty_bgs_lock); } if (!list_empty(&block_group->dirty_list)) { list_del_init(&block_group->dirty_list); btrfs_put_block_group(block_group); } spin_unlock(&trans->transaction->dirty_bgs_lock); mutex_unlock(&trans->transaction->cache_write_mutex); if (!IS_ERR(inode)) { ret = btrfs_orphan_add(trans, inode); if (ret) { btrfs_add_delayed_iput(inode); goto out; } clear_nlink(inode); /* One for the block groups ref */ spin_lock(&block_group->lock); if (block_group->iref) { block_group->iref = 0; block_group->inode = NULL; spin_unlock(&block_group->lock); iput(inode); } else { spin_unlock(&block_group->lock); } /* One for our lookup ref */ btrfs_add_delayed_iput(inode); } key.objectid = BTRFS_FREE_SPACE_OBJECTID; key.offset = block_group->key.objectid; key.type = 0; ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); if (ret < 0) goto out; if (ret > 0) btrfs_release_path(path); if (ret == 0) { ret = btrfs_del_item(trans, tree_root, path); if (ret) goto out; btrfs_release_path(path); } spin_lock(&root->fs_info->block_group_cache_lock); rb_erase(&block_group->cache_node, &root->fs_info->block_group_cache_tree); RB_CLEAR_NODE(&block_group->cache_node); if (root->fs_info->first_logical_byte == block_group->key.objectid) root->fs_info->first_logical_byte = (u64)-1; spin_unlock(&root->fs_info->block_group_cache_lock); down_write(&block_group->space_info->groups_sem); /* * we must use list_del_init so people can check to see if they * are still on the list after taking the semaphore */ list_del_init(&block_group->list); if (list_empty(&block_group->space_info->block_groups[index])) { kobj = block_group->space_info->block_group_kobjs[index]; block_group->space_info->block_group_kobjs[index] = NULL; clear_avail_alloc_bits(root->fs_info, block_group->flags); } up_write(&block_group->space_info->groups_sem); if (kobj) { kobject_del(kobj); kobject_put(kobj); } if (block_group->has_caching_ctl) caching_ctl = get_caching_control(block_group); if (block_group->cached == BTRFS_CACHE_STARTED) wait_block_group_cache_done(block_group); if (block_group->has_caching_ctl) { down_write(&root->fs_info->commit_root_sem); if (!caching_ctl) { struct btrfs_caching_control *ctl; list_for_each_entry(ctl, &root->fs_info->caching_block_groups, list) if (ctl->block_group == block_group) { caching_ctl = ctl; atomic_inc(&caching_ctl->count); break; } } if (caching_ctl) list_del_init(&caching_ctl->list); up_write(&root->fs_info->commit_root_sem); if (caching_ctl) { /* Once for the caching bgs list and once for us. */ put_caching_control(caching_ctl); put_caching_control(caching_ctl); } } spin_lock(&trans->transaction->dirty_bgs_lock); if (!list_empty(&block_group->dirty_list)) { WARN_ON(1); } if (!list_empty(&block_group->io_list)) { WARN_ON(1); } spin_unlock(&trans->transaction->dirty_bgs_lock); btrfs_remove_free_space_cache(block_group); spin_lock(&block_group->space_info->lock); list_del_init(&block_group->ro_list); if (btrfs_test_opt(root, ENOSPC_DEBUG)) { WARN_ON(block_group->space_info->total_bytes < block_group->key.offset); WARN_ON(block_group->space_info->bytes_readonly < block_group->key.offset); WARN_ON(block_group->space_info->disk_total < block_group->key.offset * factor); } block_group->space_info->total_bytes -= block_group->key.offset; block_group->space_info->bytes_readonly -= block_group->key.offset; block_group->space_info->disk_total -= block_group->key.offset * factor; spin_unlock(&block_group->space_info->lock); memcpy(&key, &block_group->key, sizeof(key)); lock_chunks(root); if (!list_empty(&em->list)) { /* We're in the transaction->pending_chunks list. */ free_extent_map(em); } spin_lock(&block_group->lock); block_group->removed = 1; /* * At this point trimming can't start on this block group, because we * removed the block group from the tree fs_info->block_group_cache_tree * so no one can't find it anymore and even if someone already got this * block group before we removed it from the rbtree, they have already * incremented block_group->trimming - if they didn't, they won't find * any free space entries because we already removed them all when we * called btrfs_remove_free_space_cache(). * * And we must not remove the extent map from the fs_info->mapping_tree * to prevent the same logical address range and physical device space * ranges from being reused for a new block group. This is because our * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is * completely transactionless, so while it is trimming a range the * currently running transaction might finish and a new one start, * allowing for new block groups to be created that can reuse the same * physical device locations unless we take this special care. * * There may also be an implicit trim operation if the file system * is mounted with -odiscard. The same protections must remain * in place until the extents have been discarded completely when * the transaction commit has completed. */ remove_em = (atomic_read(&block_group->trimming) == 0); /* * Make sure a trimmer task always sees the em in the pinned_chunks list * if it sees block_group->removed == 1 (needs to lock block_group->lock * before checking block_group->removed). */ if (!remove_em) { /* * Our em might be in trans->transaction->pending_chunks which * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks), * and so is the fs_info->pinned_chunks list. * * So at this point we must be holding the chunk_mutex to avoid * any races with chunk allocation (more specifically at * volumes.c:contains_pending_extent()), to ensure it always * sees the em, either in the pending_chunks list or in the * pinned_chunks list. */ list_move_tail(&em->list, &root->fs_info->pinned_chunks); } spin_unlock(&block_group->lock); if (remove_em) { struct extent_map_tree *em_tree; em_tree = &root->fs_info->mapping_tree.map_tree; write_lock(&em_tree->lock); /* * The em might be in the pending_chunks list, so make sure the * chunk mutex is locked, since remove_extent_mapping() will * delete us from that list. */ remove_extent_mapping(em_tree, em); write_unlock(&em_tree->lock); /* once for the tree */ free_extent_map(em); } unlock_chunks(root); btrfs_put_block_group(block_group); btrfs_put_block_group(block_group); ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret > 0) ret = -EIO; if (ret < 0) goto out; ret = btrfs_del_item(trans, root, path); out: btrfs_free_path(path); return ret; } /* * Process the unused_bgs list and remove any that don't have any allocated * space inside of them. */ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) { struct btrfs_block_group_cache *block_group; struct btrfs_space_info *space_info; struct btrfs_root *root = fs_info->extent_root; struct btrfs_trans_handle *trans; int ret = 0; if (!fs_info->open) return; spin_lock(&fs_info->unused_bgs_lock); while (!list_empty(&fs_info->unused_bgs)) { u64 start, end; int trimming; block_group = list_first_entry(&fs_info->unused_bgs, struct btrfs_block_group_cache, bg_list); space_info = block_group->space_info; list_del_init(&block_group->bg_list); if (ret || btrfs_mixed_space_info(space_info)) { btrfs_put_block_group(block_group); continue; } spin_unlock(&fs_info->unused_bgs_lock); mutex_lock(&root->fs_info->delete_unused_bgs_mutex); /* Don't want to race with allocators so take the groups_sem */ down_write(&space_info->groups_sem); spin_lock(&block_group->lock); if (block_group->reserved || btrfs_block_group_used(&block_group->item) || block_group->ro) { /* * We want to bail if we made new allocations or have * outstanding allocations in this block group. We do * the ro check in case balance is currently acting on * this block group. */ spin_unlock(&block_group->lock); up_write(&space_info->groups_sem); goto next; } spin_unlock(&block_group->lock); /* We don't want to force the issue, only flip if it's ok. */ ret = inc_block_group_ro(block_group, 0); up_write(&space_info->groups_sem); if (ret < 0) { ret = 0; goto next; } /* * Want to do this before we do anything else so we can recover * properly if we fail to join the transaction. */ /* 1 for btrfs_orphan_reserve_metadata() */ trans = btrfs_start_transaction(root, 1); if (IS_ERR(trans)) { btrfs_dec_block_group_ro(root, block_group); ret = PTR_ERR(trans); goto next; } /* * We could have pending pinned extents for this block group, * just delete them, we don't care about them anymore. */ start = block_group->key.objectid; end = start + block_group->key.offset - 1; /* * Hold the unused_bg_unpin_mutex lock to avoid racing with * btrfs_finish_extent_commit(). If we are at transaction N, * another task might be running finish_extent_commit() for the * previous transaction N - 1, and have seen a range belonging * to the block group in freed_extents[] before we were able to * clear the whole block group range from freed_extents[]. This * means that task can lookup for the block group after we * unpinned it from freed_extents[] and removed it, leading to * a BUG_ON() at btrfs_unpin_extent_range(). */ mutex_lock(&fs_info->unused_bg_unpin_mutex); ret = clear_extent_bits(&fs_info->freed_extents[0], start, end, EXTENT_DIRTY, GFP_NOFS); if (ret) { mutex_unlock(&fs_info->unused_bg_unpin_mutex); btrfs_dec_block_group_ro(root, block_group); goto end_trans; } ret = clear_extent_bits(&fs_info->freed_extents[1], start, end, EXTENT_DIRTY, GFP_NOFS); if (ret) { mutex_unlock(&fs_info->unused_bg_unpin_mutex); btrfs_dec_block_group_ro(root, block_group); goto end_trans; } mutex_unlock(&fs_info->unused_bg_unpin_mutex); /* Reset pinned so btrfs_put_block_group doesn't complain */ spin_lock(&space_info->lock); spin_lock(&block_group->lock); space_info->bytes_pinned -= block_group->pinned; space_info->bytes_readonly += block_group->pinned; percpu_counter_add(&space_info->total_bytes_pinned, -block_group->pinned); block_group->pinned = 0; spin_unlock(&block_group->lock); spin_unlock(&space_info->lock); /* DISCARD can flip during remount */ trimming = btrfs_test_opt(root, DISCARD); /* Implicit trim during transaction commit. */ if (trimming) btrfs_get_block_group_trimming(block_group); /* * Btrfs_remove_chunk will abort the transaction if things go * horribly wrong. */ ret = btrfs_remove_chunk(trans, root, block_group->key.objectid); if (ret) { if (trimming) btrfs_put_block_group_trimming(block_group); goto end_trans; } /* * If we're not mounted with -odiscard, we can just forget * about this block group. Otherwise we'll need to wait * until transaction commit to do the actual discard. */ if (trimming) { WARN_ON(!list_empty(&block_group->bg_list)); spin_lock(&trans->transaction->deleted_bgs_lock); list_move(&block_group->bg_list, &trans->transaction->deleted_bgs); spin_unlock(&trans->transaction->deleted_bgs_lock); btrfs_get_block_group(block_group); } end_trans: btrfs_end_transaction(trans, root); next: mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); btrfs_put_block_group(block_group); spin_lock(&fs_info->unused_bgs_lock); } spin_unlock(&fs_info->unused_bgs_lock); } int btrfs_init_space_info(struct btrfs_fs_info *fs_info) { struct btrfs_space_info *space_info; struct btrfs_super_block *disk_super; u64 features; u64 flags; int mixed = 0; int ret; disk_super = fs_info->super_copy; if (!btrfs_super_root(disk_super)) return 1; features = btrfs_super_incompat_flags(disk_super); if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) mixed = 1; flags = BTRFS_BLOCK_GROUP_SYSTEM; ret = update_space_info(fs_info, flags, 0, 0, &space_info); if (ret) goto out; if (mixed) { flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA; ret = update_space_info(fs_info, flags, 0, 0, &space_info); } else { flags = BTRFS_BLOCK_GROUP_METADATA; ret = update_space_info(fs_info, flags, 0, 0, &space_info); if (ret) goto out; flags = BTRFS_BLOCK_GROUP_DATA; ret = update_space_info(fs_info, flags, 0, 0, &space_info); } out: return ret; } int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end) { return unpin_extent_range(root, start, end, false); } /* * It used to be that old block groups would be left around forever. * Iterating over them would be enough to trim unused space. Since we * now automatically remove them, we also need to iterate over unallocated * space. * * We don't want a transaction for this since the discard may take a * substantial amount of time. We don't require that a transaction be * running, but we do need to take a running transaction into account * to ensure that we're not discarding chunks that were released in * the current transaction. * * Holding the chunks lock will prevent other threads from allocating * or releasing chunks, but it won't prevent a running transaction * from committing and releasing the memory that the pending chunks * list head uses. For that, we need to take a reference to the * transaction. */ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 minlen, u64 *trimmed) { u64 start = 0, len = 0; int ret; *trimmed = 0; /* Not writeable = nothing to do. */ if (!device->writeable) return 0; /* No free space = nothing to do. */ if (device->total_bytes <= device->bytes_used) return 0; ret = 0; while (1) { struct btrfs_fs_info *fs_info = device->dev_root->fs_info; struct btrfs_transaction *trans; u64 bytes; ret = mutex_lock_interruptible(&fs_info->chunk_mutex); if (ret) return ret; down_read(&fs_info->commit_root_sem); spin_lock(&fs_info->trans_lock); trans = fs_info->running_transaction; if (trans) atomic_inc(&trans->use_count); spin_unlock(&fs_info->trans_lock); ret = find_free_dev_extent_start(trans, device, minlen, start, &start, &len); if (trans) btrfs_put_transaction(trans); if (ret) { up_read(&fs_info->commit_root_sem); mutex_unlock(&fs_info->chunk_mutex); if (ret == -ENOSPC) ret = 0; break; } ret = btrfs_issue_discard(device->bdev, start, len, &bytes); up_read(&fs_info->commit_root_sem); mutex_unlock(&fs_info->chunk_mutex); if (ret) break; start += len; *trimmed += bytes; if (fatal_signal_pending(current)) { ret = -ERESTARTSYS; break; } cond_resched(); } return ret; } int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_block_group_cache *cache = NULL; struct btrfs_device *device; struct list_head *devices; u64 group_trimmed; u64 start; u64 end; u64 trimmed = 0; u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy); int ret = 0; /* * try to trim all FS space, our block group may start from non-zero. */ if (range->len == total_bytes) cache = btrfs_lookup_first_block_group(fs_info, range->start); else cache = btrfs_lookup_block_group(fs_info, range->start); while (cache) { if (cache->key.objectid >= (range->start + range->len)) { btrfs_put_block_group(cache); break; } start = max(range->start, cache->key.objectid); end = min(range->start + range->len, cache->key.objectid + cache->key.offset); if (end - start >= range->minlen) { if (!block_group_cache_done(cache)) { ret = cache_block_group(cache, 0); if (ret) { btrfs_put_block_group(cache); break; } ret = wait_block_group_cache_done(cache); if (ret) { btrfs_put_block_group(cache); break; } } ret = btrfs_trim_block_group(cache, &group_trimmed, start, end, range->minlen); trimmed += group_trimmed; if (ret) { btrfs_put_block_group(cache); break; } } cache = next_block_group(fs_info->tree_root, cache); } mutex_lock(&root->fs_info->fs_devices->device_list_mutex); devices = &root->fs_info->fs_devices->alloc_list; list_for_each_entry(device, devices, dev_alloc_list) { ret = btrfs_trim_free_extents(device, range->minlen, &group_trimmed); if (ret) break; trimmed += group_trimmed; } mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); range->len = trimmed; return ret; } /* * btrfs_{start,end}_write_no_snapshoting() are similar to * mnt_{want,drop}_write(), they are used to prevent some tasks from writing * data into the page cache through nocow before the subvolume is snapshoted, * but flush the data into disk after the snapshot creation, or to prevent * operations while snapshoting is ongoing and that cause the snapshot to be * inconsistent (writes followed by expanding truncates for example). */ void btrfs_end_write_no_snapshoting(struct btrfs_root *root) { percpu_counter_dec(&root->subv_writers->counter); /* * Make sure counter is updated before we wake up waiters. */ smp_mb(); if (waitqueue_active(&root->subv_writers->wait)) wake_up(&root->subv_writers->wait); } int btrfs_start_write_no_snapshoting(struct btrfs_root *root) { if (atomic_read(&root->will_be_snapshoted)) return 0; percpu_counter_inc(&root->subv_writers->counter); /* * Make sure counter is updated before we check for snapshot creation. */ smp_mb(); if (atomic_read(&root->will_be_snapshoted)) { btrfs_end_write_no_snapshoting(root); return 0; } return 1; }