// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2012 Fusion-io All rights reserved. * Copyright (C) 2012 Intel Corp. All rights reserved. */ #include #include #include #include #include #include #include #include #include #include "ctree.h" #include "disk-io.h" #include "volumes.h" #include "raid56.h" #include "async-thread.h" /* set when additional merges to this rbio are not allowed */ #define RBIO_RMW_LOCKED_BIT 1 /* * set when this rbio is sitting in the hash, but it is just a cache * of past RMW */ #define RBIO_CACHE_BIT 2 /* * set when it is safe to trust the stripe_pages for caching */ #define RBIO_CACHE_READY_BIT 3 #define RBIO_CACHE_SIZE 1024 #define BTRFS_STRIPE_HASH_TABLE_BITS 11 /* Used by the raid56 code to lock stripes for read/modify/write */ struct btrfs_stripe_hash { struct list_head hash_list; spinlock_t lock; }; /* Used by the raid56 code to lock stripes for read/modify/write */ struct btrfs_stripe_hash_table { struct list_head stripe_cache; spinlock_t cache_lock; int cache_size; struct btrfs_stripe_hash table[]; }; enum btrfs_rbio_ops { BTRFS_RBIO_WRITE, BTRFS_RBIO_READ_REBUILD, BTRFS_RBIO_PARITY_SCRUB, BTRFS_RBIO_REBUILD_MISSING, }; struct btrfs_raid_bio { struct btrfs_fs_info *fs_info; struct btrfs_bio *bbio; /* while we're doing rmw on a stripe * we put it into a hash table so we can * lock the stripe and merge more rbios * into it. */ struct list_head hash_list; /* * LRU list for the stripe cache */ struct list_head stripe_cache; /* * for scheduling work in the helper threads */ struct btrfs_work work; /* * bio list and bio_list_lock are used * to add more bios into the stripe * in hopes of avoiding the full rmw */ struct bio_list bio_list; spinlock_t bio_list_lock; /* also protected by the bio_list_lock, the * plug list is used by the plugging code * to collect partial bios while plugged. The * stripe locking code also uses it to hand off * the stripe lock to the next pending IO */ struct list_head plug_list; /* * flags that tell us if it is safe to * merge with this bio */ unsigned long flags; /* size of each individual stripe on disk */ int stripe_len; /* number of data stripes (no p/q) */ int nr_data; int real_stripes; int stripe_npages; /* * set if we're doing a parity rebuild * for a read from higher up, which is handled * differently from a parity rebuild as part of * rmw */ enum btrfs_rbio_ops operation; /* first bad stripe */ int faila; /* second bad stripe (for raid6 use) */ int failb; int scrubp; /* * number of pages needed to represent the full * stripe */ int nr_pages; /* * size of all the bios in the bio_list. This * helps us decide if the rbio maps to a full * stripe or not */ int bio_list_bytes; int generic_bio_cnt; refcount_t refs; atomic_t stripes_pending; atomic_t error; /* * these are two arrays of pointers. We allocate the * rbio big enough to hold them both and setup their * locations when the rbio is allocated */ /* pointers to pages that we allocated for * reading/writing stripes directly from the disk (including P/Q) */ struct page **stripe_pages; /* * pointers to the pages in the bio_list. Stored * here for faster lookup */ struct page **bio_pages; /* * bitmap to record which horizontal stripe has data */ unsigned long *dbitmap; /* allocated with real_stripes-many pointers for finish_*() calls */ void **finish_pointers; /* allocated with stripe_npages-many bits for finish_*() calls */ unsigned long *finish_pbitmap; }; static int __raid56_parity_recover(struct btrfs_raid_bio *rbio); static noinline void finish_rmw(struct btrfs_raid_bio *rbio); static void rmw_work(struct btrfs_work *work); static void read_rebuild_work(struct btrfs_work *work); static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio); static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed); static void __free_raid_bio(struct btrfs_raid_bio *rbio); static void index_rbio_pages(struct btrfs_raid_bio *rbio); static int alloc_rbio_pages(struct btrfs_raid_bio *rbio); static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, int need_check); static void scrub_parity_work(struct btrfs_work *work); static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func) { btrfs_init_work(&rbio->work, work_func, NULL, NULL); btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work); } /* * the stripe hash table is used for locking, and to collect * bios in hopes of making a full stripe */ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info) { struct btrfs_stripe_hash_table *table; struct btrfs_stripe_hash_table *x; struct btrfs_stripe_hash *cur; struct btrfs_stripe_hash *h; int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS; int i; int table_size; if (info->stripe_hash_table) return 0; /* * The table is large, starting with order 4 and can go as high as * order 7 in case lock debugging is turned on. * * Try harder to allocate and fallback to vmalloc to lower the chance * of a failing mount. */ table_size = sizeof(*table) + sizeof(*h) * num_entries; table = kvzalloc(table_size, GFP_KERNEL); if (!table) return -ENOMEM; spin_lock_init(&table->cache_lock); INIT_LIST_HEAD(&table->stripe_cache); h = table->table; for (i = 0; i < num_entries; i++) { cur = h + i; INIT_LIST_HEAD(&cur->hash_list); spin_lock_init(&cur->lock); } x = cmpxchg(&info->stripe_hash_table, NULL, table); if (x) kvfree(x); return 0; } /* * caching an rbio means to copy anything from the * bio_pages array into the stripe_pages array. We * use the page uptodate bit in the stripe cache array * to indicate if it has valid data * * once the caching is done, we set the cache ready * bit. */ static void cache_rbio_pages(struct btrfs_raid_bio *rbio) { int i; char *s; char *d; int ret; ret = alloc_rbio_pages(rbio); if (ret) return; for (i = 0; i < rbio->nr_pages; i++) { if (!rbio->bio_pages[i]) continue; s = kmap(rbio->bio_pages[i]); d = kmap(rbio->stripe_pages[i]); copy_page(d, s); kunmap(rbio->bio_pages[i]); kunmap(rbio->stripe_pages[i]); SetPageUptodate(rbio->stripe_pages[i]); } set_bit(RBIO_CACHE_READY_BIT, &rbio->flags); } /* * we hash on the first logical address of the stripe */ static int rbio_bucket(struct btrfs_raid_bio *rbio) { u64 num = rbio->bbio->raid_map[0]; /* * we shift down quite a bit. We're using byte * addressing, and most of the lower bits are zeros. * This tends to upset hash_64, and it consistently * returns just one or two different values. * * shifting off the lower bits fixes things. */ return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS); } /* * stealing an rbio means taking all the uptodate pages from the stripe * array in the source rbio and putting them into the destination rbio */ static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest) { int i; struct page *s; struct page *d; if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags)) return; for (i = 0; i < dest->nr_pages; i++) { s = src->stripe_pages[i]; if (!s || !PageUptodate(s)) { continue; } d = dest->stripe_pages[i]; if (d) __free_page(d); dest->stripe_pages[i] = s; src->stripe_pages[i] = NULL; } } /* * merging means we take the bio_list from the victim and * splice it into the destination. The victim should * be discarded afterwards. * * must be called with dest->rbio_list_lock held */ static void merge_rbio(struct btrfs_raid_bio *dest, struct btrfs_raid_bio *victim) { bio_list_merge(&dest->bio_list, &victim->bio_list); dest->bio_list_bytes += victim->bio_list_bytes; dest->generic_bio_cnt += victim->generic_bio_cnt; bio_list_init(&victim->bio_list); } /* * used to prune items that are in the cache. The caller * must hold the hash table lock. */ static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio) { int bucket = rbio_bucket(rbio); struct btrfs_stripe_hash_table *table; struct btrfs_stripe_hash *h; int freeit = 0; /* * check the bit again under the hash table lock. */ if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) return; table = rbio->fs_info->stripe_hash_table; h = table->table + bucket; /* hold the lock for the bucket because we may be * removing it from the hash table */ spin_lock(&h->lock); /* * hold the lock for the bio list because we need * to make sure the bio list is empty */ spin_lock(&rbio->bio_list_lock); if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) { list_del_init(&rbio->stripe_cache); table->cache_size -= 1; freeit = 1; /* if the bio list isn't empty, this rbio is * still involved in an IO. We take it out * of the cache list, and drop the ref that * was held for the list. * * If the bio_list was empty, we also remove * the rbio from the hash_table, and drop * the corresponding ref */ if (bio_list_empty(&rbio->bio_list)) { if (!list_empty(&rbio->hash_list)) { list_del_init(&rbio->hash_list); refcount_dec(&rbio->refs); BUG_ON(!list_empty(&rbio->plug_list)); } } } spin_unlock(&rbio->bio_list_lock); spin_unlock(&h->lock); if (freeit) __free_raid_bio(rbio); } /* * prune a given rbio from the cache */ static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio) { struct btrfs_stripe_hash_table *table; unsigned long flags; if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) return; table = rbio->fs_info->stripe_hash_table; spin_lock_irqsave(&table->cache_lock, flags); __remove_rbio_from_cache(rbio); spin_unlock_irqrestore(&table->cache_lock, flags); } /* * remove everything in the cache */ static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info) { struct btrfs_stripe_hash_table *table; unsigned long flags; struct btrfs_raid_bio *rbio; table = info->stripe_hash_table; spin_lock_irqsave(&table->cache_lock, flags); while (!list_empty(&table->stripe_cache)) { rbio = list_entry(table->stripe_cache.next, struct btrfs_raid_bio, stripe_cache); __remove_rbio_from_cache(rbio); } spin_unlock_irqrestore(&table->cache_lock, flags); } /* * remove all cached entries and free the hash table * used by unmount */ void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info) { if (!info->stripe_hash_table) return; btrfs_clear_rbio_cache(info); kvfree(info->stripe_hash_table); info->stripe_hash_table = NULL; } /* * insert an rbio into the stripe cache. It * must have already been prepared by calling * cache_rbio_pages * * If this rbio was already cached, it gets * moved to the front of the lru. * * If the size of the rbio cache is too big, we * prune an item. */ static void cache_rbio(struct btrfs_raid_bio *rbio) { struct btrfs_stripe_hash_table *table; unsigned long flags; if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags)) return; table = rbio->fs_info->stripe_hash_table; spin_lock_irqsave(&table->cache_lock, flags); spin_lock(&rbio->bio_list_lock); /* bump our ref if we were not in the list before */ if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags)) refcount_inc(&rbio->refs); if (!list_empty(&rbio->stripe_cache)){ list_move(&rbio->stripe_cache, &table->stripe_cache); } else { list_add(&rbio->stripe_cache, &table->stripe_cache); table->cache_size += 1; } spin_unlock(&rbio->bio_list_lock); if (table->cache_size > RBIO_CACHE_SIZE) { struct btrfs_raid_bio *found; found = list_entry(table->stripe_cache.prev, struct btrfs_raid_bio, stripe_cache); if (found != rbio) __remove_rbio_from_cache(found); } spin_unlock_irqrestore(&table->cache_lock, flags); } /* * helper function to run the xor_blocks api. It is only * able to do MAX_XOR_BLOCKS at a time, so we need to * loop through. */ static void run_xor(void **pages, int src_cnt, ssize_t len) { int src_off = 0; int xor_src_cnt = 0; void *dest = pages[src_cnt]; while(src_cnt > 0) { xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS); xor_blocks(xor_src_cnt, len, dest, pages + src_off); src_cnt -= xor_src_cnt; src_off += xor_src_cnt; } } /* * Returns true if the bio list inside this rbio covers an entire stripe (no * rmw required). */ static int rbio_is_full(struct btrfs_raid_bio *rbio) { unsigned long flags; unsigned long size = rbio->bio_list_bytes; int ret = 1; spin_lock_irqsave(&rbio->bio_list_lock, flags); if (size != rbio->nr_data * rbio->stripe_len) ret = 0; BUG_ON(size > rbio->nr_data * rbio->stripe_len); spin_unlock_irqrestore(&rbio->bio_list_lock, flags); return ret; } /* * returns 1 if it is safe to merge two rbios together. * The merging is safe if the two rbios correspond to * the same stripe and if they are both going in the same * direction (read vs write), and if neither one is * locked for final IO * * The caller is responsible for locking such that * rmw_locked is safe to test */ static int rbio_can_merge(struct btrfs_raid_bio *last, struct btrfs_raid_bio *cur) { if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) || test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) return 0; /* * we can't merge with cached rbios, since the * idea is that when we merge the destination * rbio is going to run our IO for us. We can * steal from cached rbios though, other functions * handle that. */ if (test_bit(RBIO_CACHE_BIT, &last->flags) || test_bit(RBIO_CACHE_BIT, &cur->flags)) return 0; if (last->bbio->raid_map[0] != cur->bbio->raid_map[0]) return 0; /* we can't merge with different operations */ if (last->operation != cur->operation) return 0; /* * We've need read the full stripe from the drive. * check and repair the parity and write the new results. * * We're not allowed to add any new bios to the * bio list here, anyone else that wants to * change this stripe needs to do their own rmw. */ if (last->operation == BTRFS_RBIO_PARITY_SCRUB) return 0; if (last->operation == BTRFS_RBIO_REBUILD_MISSING) return 0; if (last->operation == BTRFS_RBIO_READ_REBUILD) { int fa = last->faila; int fb = last->failb; int cur_fa = cur->faila; int cur_fb = cur->failb; if (last->faila >= last->failb) { fa = last->failb; fb = last->faila; } if (cur->faila >= cur->failb) { cur_fa = cur->failb; cur_fb = cur->faila; } if (fa != cur_fa || fb != cur_fb) return 0; } return 1; } static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe, int index) { return stripe * rbio->stripe_npages + index; } /* * these are just the pages from the rbio array, not from anything * the FS sent down to us */ static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe, int index) { return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)]; } /* * helper to index into the pstripe */ static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index) { return rbio_stripe_page(rbio, rbio->nr_data, index); } /* * helper to index into the qstripe, returns null * if there is no qstripe */ static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index) { if (rbio->nr_data + 1 == rbio->real_stripes) return NULL; return rbio_stripe_page(rbio, rbio->nr_data + 1, index); } /* * The first stripe in the table for a logical address * has the lock. rbios are added in one of three ways: * * 1) Nobody has the stripe locked yet. The rbio is given * the lock and 0 is returned. The caller must start the IO * themselves. * * 2) Someone has the stripe locked, but we're able to merge * with the lock owner. The rbio is freed and the IO will * start automatically along with the existing rbio. 1 is returned. * * 3) Someone has the stripe locked, but we're not able to merge. * The rbio is added to the lock owner's plug list, or merged into * an rbio already on the plug list. When the lock owner unlocks, * the next rbio on the list is run and the IO is started automatically. * 1 is returned * * If we return 0, the caller still owns the rbio and must continue with * IO submission. If we return 1, the caller must assume the rbio has * already been freed. */ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio) { struct btrfs_stripe_hash *h; struct btrfs_raid_bio *cur; struct btrfs_raid_bio *pending; unsigned long flags; struct btrfs_raid_bio *freeit = NULL; struct btrfs_raid_bio *cache_drop = NULL; int ret = 0; h = rbio->fs_info->stripe_hash_table->table + rbio_bucket(rbio); spin_lock_irqsave(&h->lock, flags); list_for_each_entry(cur, &h->hash_list, hash_list) { if (cur->bbio->raid_map[0] != rbio->bbio->raid_map[0]) continue; spin_lock(&cur->bio_list_lock); /* Can we steal this cached rbio's pages? */ if (bio_list_empty(&cur->bio_list) && list_empty(&cur->plug_list) && test_bit(RBIO_CACHE_BIT, &cur->flags) && !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) { list_del_init(&cur->hash_list); refcount_dec(&cur->refs); steal_rbio(cur, rbio); cache_drop = cur; spin_unlock(&cur->bio_list_lock); goto lockit; } /* Can we merge into the lock owner? */ if (rbio_can_merge(cur, rbio)) { merge_rbio(cur, rbio); spin_unlock(&cur->bio_list_lock); freeit = rbio; ret = 1; goto out; } /* * We couldn't merge with the running rbio, see if we can merge * with the pending ones. We don't have to check for rmw_locked * because there is no way they are inside finish_rmw right now */ list_for_each_entry(pending, &cur->plug_list, plug_list) { if (rbio_can_merge(pending, rbio)) { merge_rbio(pending, rbio); spin_unlock(&cur->bio_list_lock); freeit = rbio; ret = 1; goto out; } } /* * No merging, put us on the tail of the plug list, our rbio * will be started with the currently running rbio unlocks */ list_add_tail(&rbio->plug_list, &cur->plug_list); spin_unlock(&cur->bio_list_lock); ret = 1; goto out; } lockit: refcount_inc(&rbio->refs); list_add(&rbio->hash_list, &h->hash_list); out: spin_unlock_irqrestore(&h->lock, flags); if (cache_drop) remove_rbio_from_cache(cache_drop); if (freeit) __free_raid_bio(freeit); return ret; } /* * called as rmw or parity rebuild is completed. If the plug list has more * rbios waiting for this stripe, the next one on the list will be started */ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio) { int bucket; struct btrfs_stripe_hash *h; unsigned long flags; int keep_cache = 0; bucket = rbio_bucket(rbio); h = rbio->fs_info->stripe_hash_table->table + bucket; if (list_empty(&rbio->plug_list)) cache_rbio(rbio); spin_lock_irqsave(&h->lock, flags); spin_lock(&rbio->bio_list_lock); if (!list_empty(&rbio->hash_list)) { /* * if we're still cached and there is no other IO * to perform, just leave this rbio here for others * to steal from later */ if (list_empty(&rbio->plug_list) && test_bit(RBIO_CACHE_BIT, &rbio->flags)) { keep_cache = 1; clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); BUG_ON(!bio_list_empty(&rbio->bio_list)); goto done; } list_del_init(&rbio->hash_list); refcount_dec(&rbio->refs); /* * we use the plug list to hold all the rbios * waiting for the chance to lock this stripe. * hand the lock over to one of them. */ if (!list_empty(&rbio->plug_list)) { struct btrfs_raid_bio *next; struct list_head *head = rbio->plug_list.next; next = list_entry(head, struct btrfs_raid_bio, plug_list); list_del_init(&rbio->plug_list); list_add(&next->hash_list, &h->hash_list); refcount_inc(&next->refs); spin_unlock(&rbio->bio_list_lock); spin_unlock_irqrestore(&h->lock, flags); if (next->operation == BTRFS_RBIO_READ_REBUILD) start_async_work(next, read_rebuild_work); else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) { steal_rbio(rbio, next); start_async_work(next, read_rebuild_work); } else if (next->operation == BTRFS_RBIO_WRITE) { steal_rbio(rbio, next); start_async_work(next, rmw_work); } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) { steal_rbio(rbio, next); start_async_work(next, scrub_parity_work); } goto done_nolock; } } done: spin_unlock(&rbio->bio_list_lock); spin_unlock_irqrestore(&h->lock, flags); done_nolock: if (!keep_cache) remove_rbio_from_cache(rbio); } static void __free_raid_bio(struct btrfs_raid_bio *rbio) { int i; if (!refcount_dec_and_test(&rbio->refs)) return; WARN_ON(!list_empty(&rbio->stripe_cache)); WARN_ON(!list_empty(&rbio->hash_list)); WARN_ON(!bio_list_empty(&rbio->bio_list)); for (i = 0; i < rbio->nr_pages; i++) { if (rbio->stripe_pages[i]) { __free_page(rbio->stripe_pages[i]); rbio->stripe_pages[i] = NULL; } } btrfs_put_bbio(rbio->bbio); kfree(rbio); } static void rbio_endio_bio_list(struct bio *cur, blk_status_t err) { struct bio *next; while (cur) { next = cur->bi_next; cur->bi_next = NULL; cur->bi_status = err; bio_endio(cur); cur = next; } } /* * this frees the rbio and runs through all the bios in the * bio_list and calls end_io on them */ static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err) { struct bio *cur = bio_list_get(&rbio->bio_list); struct bio *extra; if (rbio->generic_bio_cnt) btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt); /* * At this moment, rbio->bio_list is empty, however since rbio does not * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the * hash list, rbio may be merged with others so that rbio->bio_list * becomes non-empty. * Once unlock_stripe() is done, rbio->bio_list will not be updated any * more and we can call bio_endio() on all queued bios. */ unlock_stripe(rbio); extra = bio_list_get(&rbio->bio_list); __free_raid_bio(rbio); rbio_endio_bio_list(cur, err); if (extra) rbio_endio_bio_list(extra, err); } /* * end io function used by finish_rmw. When we finally * get here, we've written a full stripe */ static void raid_write_end_io(struct bio *bio) { struct btrfs_raid_bio *rbio = bio->bi_private; blk_status_t err = bio->bi_status; int max_errors; if (err) fail_bio_stripe(rbio, bio); bio_put(bio); if (!atomic_dec_and_test(&rbio->stripes_pending)) return; err = BLK_STS_OK; /* OK, we have read all the stripes we need to. */ max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ? 0 : rbio->bbio->max_errors; if (atomic_read(&rbio->error) > max_errors) err = BLK_STS_IOERR; rbio_orig_end_io(rbio, err); } /* * the read/modify/write code wants to use the original bio for * any pages it included, and then use the rbio for everything * else. This function decides if a given index (stripe number) * and page number in that stripe fall inside the original bio * or the rbio. * * if you set bio_list_only, you'll get a NULL back for any ranges * that are outside the bio_list * * This doesn't take any refs on anything, you get a bare page pointer * and the caller must bump refs as required. * * You must call index_rbio_pages once before you can trust * the answers from this function. */ static struct page *page_in_rbio(struct btrfs_raid_bio *rbio, int index, int pagenr, int bio_list_only) { int chunk_page; struct page *p = NULL; chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr; spin_lock_irq(&rbio->bio_list_lock); p = rbio->bio_pages[chunk_page]; spin_unlock_irq(&rbio->bio_list_lock); if (p || bio_list_only) return p; return rbio->stripe_pages[chunk_page]; } /* * number of pages we need for the entire stripe across all the * drives */ static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes) { return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes; } /* * allocation and initial setup for the btrfs_raid_bio. Not * this does not allocate any pages for rbio->pages. */ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info, struct btrfs_bio *bbio, u64 stripe_len) { struct btrfs_raid_bio *rbio; int nr_data = 0; int real_stripes = bbio->num_stripes - bbio->num_tgtdevs; int num_pages = rbio_nr_pages(stripe_len, real_stripes); int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE); void *p; rbio = kzalloc(sizeof(*rbio) + sizeof(*rbio->stripe_pages) * num_pages + sizeof(*rbio->bio_pages) * num_pages + sizeof(*rbio->finish_pointers) * real_stripes + sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) + sizeof(*rbio->finish_pbitmap) * BITS_TO_LONGS(stripe_npages), GFP_NOFS); if (!rbio) return ERR_PTR(-ENOMEM); bio_list_init(&rbio->bio_list); INIT_LIST_HEAD(&rbio->plug_list); spin_lock_init(&rbio->bio_list_lock); INIT_LIST_HEAD(&rbio->stripe_cache); INIT_LIST_HEAD(&rbio->hash_list); rbio->bbio = bbio; rbio->fs_info = fs_info; rbio->stripe_len = stripe_len; rbio->nr_pages = num_pages; rbio->real_stripes = real_stripes; rbio->stripe_npages = stripe_npages; rbio->faila = -1; rbio->failb = -1; refcount_set(&rbio->refs, 1); atomic_set(&rbio->error, 0); atomic_set(&rbio->stripes_pending, 0); /* * the stripe_pages, bio_pages, etc arrays point to the extra * memory we allocated past the end of the rbio */ p = rbio + 1; #define CONSUME_ALLOC(ptr, count) do { \ ptr = p; \ p = (unsigned char *)p + sizeof(*(ptr)) * (count); \ } while (0) CONSUME_ALLOC(rbio->stripe_pages, num_pages); CONSUME_ALLOC(rbio->bio_pages, num_pages); CONSUME_ALLOC(rbio->finish_pointers, real_stripes); CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages)); CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages)); #undef CONSUME_ALLOC if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5) nr_data = real_stripes - 1; else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) nr_data = real_stripes - 2; else BUG(); rbio->nr_data = nr_data; return rbio; } /* allocate pages for all the stripes in the bio, including parity */ static int alloc_rbio_pages(struct btrfs_raid_bio *rbio) { int i; struct page *page; for (i = 0; i < rbio->nr_pages; i++) { if (rbio->stripe_pages[i]) continue; page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!page) return -ENOMEM; rbio->stripe_pages[i] = page; } return 0; } /* only allocate pages for p/q stripes */ static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio) { int i; struct page *page; i = rbio_stripe_page_index(rbio, rbio->nr_data, 0); for (; i < rbio->nr_pages; i++) { if (rbio->stripe_pages[i]) continue; page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!page) return -ENOMEM; rbio->stripe_pages[i] = page; } return 0; } /* * add a single page from a specific stripe into our list of bios for IO * this will try to merge into existing bios if possible, and returns * zero if all went well. */ static int rbio_add_io_page(struct btrfs_raid_bio *rbio, struct bio_list *bio_list, struct page *page, int stripe_nr, unsigned long page_index, unsigned long bio_max_len) { struct bio *last = bio_list->tail; u64 last_end = 0; int ret; struct bio *bio; struct btrfs_bio_stripe *stripe; u64 disk_start; stripe = &rbio->bbio->stripes[stripe_nr]; disk_start = stripe->physical + (page_index << PAGE_SHIFT); /* if the device is missing, just fail this stripe */ if (!stripe->dev->bdev) return fail_rbio_index(rbio, stripe_nr); /* see if we can add this page onto our existing bio */ if (last) { last_end = (u64)last->bi_iter.bi_sector << 9; last_end += last->bi_iter.bi_size; /* * we can't merge these if they are from different * devices or if they are not contiguous */ if (last_end == disk_start && stripe->dev->bdev && !last->bi_status && last->bi_disk == stripe->dev->bdev->bd_disk && last->bi_partno == stripe->dev->bdev->bd_partno) { ret = bio_add_page(last, page, PAGE_SIZE, 0); if (ret == PAGE_SIZE) return 0; } } /* put a new bio on the list */ bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1); bio->bi_iter.bi_size = 0; bio_set_dev(bio, stripe->dev->bdev); bio->bi_iter.bi_sector = disk_start >> 9; bio_add_page(bio, page, PAGE_SIZE, 0); bio_list_add(bio_list, bio); return 0; } /* * while we're doing the read/modify/write cycle, we could * have errors in reading pages off the disk. This checks * for errors and if we're not able to read the page it'll * trigger parity reconstruction. The rmw will be finished * after we've reconstructed the failed stripes */ static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio) { if (rbio->faila >= 0 || rbio->failb >= 0) { BUG_ON(rbio->faila == rbio->real_stripes - 1); __raid56_parity_recover(rbio); } else { finish_rmw(rbio); } } /* * helper function to walk our bio list and populate the bio_pages array with * the result. This seems expensive, but it is faster than constantly * searching through the bio list as we setup the IO in finish_rmw or stripe * reconstruction. * * This must be called before you trust the answers from page_in_rbio */ static void index_rbio_pages(struct btrfs_raid_bio *rbio) { struct bio *bio; u64 start; unsigned long stripe_offset; unsigned long page_index; spin_lock_irq(&rbio->bio_list_lock); bio_list_for_each(bio, &rbio->bio_list) { struct bio_vec bvec; struct bvec_iter iter; int i = 0; start = (u64)bio->bi_iter.bi_sector << 9; stripe_offset = start - rbio->bbio->raid_map[0]; page_index = stripe_offset >> PAGE_SHIFT; if (bio_flagged(bio, BIO_CLONED)) bio->bi_iter = btrfs_io_bio(bio)->iter; bio_for_each_segment(bvec, bio, iter) { rbio->bio_pages[page_index + i] = bvec.bv_page; i++; } } spin_unlock_irq(&rbio->bio_list_lock); } /* * this is called from one of two situations. We either * have a full stripe from the higher layers, or we've read all * the missing bits off disk. * * This will calculate the parity and then send down any * changed blocks. */ static noinline void finish_rmw(struct btrfs_raid_bio *rbio) { struct btrfs_bio *bbio = rbio->bbio; void **pointers = rbio->finish_pointers; int nr_data = rbio->nr_data; int stripe; int pagenr; bool has_qstripe; struct bio_list bio_list; struct bio *bio; int ret; bio_list_init(&bio_list); if (rbio->real_stripes - rbio->nr_data == 1) has_qstripe = false; else if (rbio->real_stripes - rbio->nr_data == 2) has_qstripe = true; else BUG(); /* at this point we either have a full stripe, * or we've read the full stripe from the drive. * recalculate the parity and write the new results. * * We're not allowed to add any new bios to the * bio list here, anyone else that wants to * change this stripe needs to do their own rmw. */ spin_lock_irq(&rbio->bio_list_lock); set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); spin_unlock_irq(&rbio->bio_list_lock); atomic_set(&rbio->error, 0); /* * now that we've set rmw_locked, run through the * bio list one last time and map the page pointers * * We don't cache full rbios because we're assuming * the higher layers are unlikely to use this area of * the disk again soon. If they do use it again, * hopefully they will send another full bio. */ index_rbio_pages(rbio); if (!rbio_is_full(rbio)) cache_rbio_pages(rbio); else clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { struct page *p; /* first collect one page from each data stripe */ for (stripe = 0; stripe < nr_data; stripe++) { p = page_in_rbio(rbio, stripe, pagenr, 0); pointers[stripe] = kmap(p); } /* then add the parity stripe */ p = rbio_pstripe_page(rbio, pagenr); SetPageUptodate(p); pointers[stripe++] = kmap(p); if (has_qstripe) { /* * raid6, add the qstripe and call the * library function to fill in our p/q */ p = rbio_qstripe_page(rbio, pagenr); SetPageUptodate(p); pointers[stripe++] = kmap(p); raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE, pointers); } else { /* raid5 */ copy_page(pointers[nr_data], pointers[0]); run_xor(pointers + 1, nr_data - 1, PAGE_SIZE); } for (stripe = 0; stripe < rbio->real_stripes; stripe++) kunmap(page_in_rbio(rbio, stripe, pagenr, 0)); } /* * time to start writing. Make bios for everything from the * higher layers (the bio_list in our rbio) and our p/q. Ignore * everything else. */ for (stripe = 0; stripe < rbio->real_stripes; stripe++) { for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { struct page *page; if (stripe < rbio->nr_data) { page = page_in_rbio(rbio, stripe, pagenr, 1); if (!page) continue; } else { page = rbio_stripe_page(rbio, stripe, pagenr); } ret = rbio_add_io_page(rbio, &bio_list, page, stripe, pagenr, rbio->stripe_len); if (ret) goto cleanup; } } if (likely(!bbio->num_tgtdevs)) goto write_data; for (stripe = 0; stripe < rbio->real_stripes; stripe++) { if (!bbio->tgtdev_map[stripe]) continue; for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { struct page *page; if (stripe < rbio->nr_data) { page = page_in_rbio(rbio, stripe, pagenr, 1); if (!page) continue; } else { page = rbio_stripe_page(rbio, stripe, pagenr); } ret = rbio_add_io_page(rbio, &bio_list, page, rbio->bbio->tgtdev_map[stripe], pagenr, rbio->stripe_len); if (ret) goto cleanup; } } write_data: atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list)); BUG_ON(atomic_read(&rbio->stripes_pending) == 0); while (1) { bio = bio_list_pop(&bio_list); if (!bio) break; bio->bi_private = rbio; bio->bi_end_io = raid_write_end_io; bio->bi_opf = REQ_OP_WRITE; submit_bio(bio); } return; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); while ((bio = bio_list_pop(&bio_list))) bio_put(bio); } /* * helper to find the stripe number for a given bio. Used to figure out which * stripe has failed. This expects the bio to correspond to a physical disk, * so it looks up based on physical sector numbers. */ static int find_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio) { u64 physical = bio->bi_iter.bi_sector; u64 stripe_start; int i; struct btrfs_bio_stripe *stripe; physical <<= 9; for (i = 0; i < rbio->bbio->num_stripes; i++) { stripe = &rbio->bbio->stripes[i]; stripe_start = stripe->physical; if (physical >= stripe_start && physical < stripe_start + rbio->stripe_len && stripe->dev->bdev && bio->bi_disk == stripe->dev->bdev->bd_disk && bio->bi_partno == stripe->dev->bdev->bd_partno) { return i; } } return -1; } /* * helper to find the stripe number for a given * bio (before mapping). Used to figure out which stripe has * failed. This looks up based on logical block numbers. */ static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio) { u64 logical = bio->bi_iter.bi_sector; u64 stripe_start; int i; logical <<= 9; for (i = 0; i < rbio->nr_data; i++) { stripe_start = rbio->bbio->raid_map[i]; if (logical >= stripe_start && logical < stripe_start + rbio->stripe_len) { return i; } } return -1; } /* * returns -EIO if we had too many failures */ static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed) { unsigned long flags; int ret = 0; spin_lock_irqsave(&rbio->bio_list_lock, flags); /* we already know this stripe is bad, move on */ if (rbio->faila == failed || rbio->failb == failed) goto out; if (rbio->faila == -1) { /* first failure on this rbio */ rbio->faila = failed; atomic_inc(&rbio->error); } else if (rbio->failb == -1) { /* second failure on this rbio */ rbio->failb = failed; atomic_inc(&rbio->error); } else { ret = -EIO; } out: spin_unlock_irqrestore(&rbio->bio_list_lock, flags); return ret; } /* * helper to fail a stripe based on a physical disk * bio. */ static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio) { int failed = find_bio_stripe(rbio, bio); if (failed < 0) return -EIO; return fail_rbio_index(rbio, failed); } /* * this sets each page in the bio uptodate. It should only be used on private * rbio pages, nothing that comes in from the higher layers */ static void set_bio_pages_uptodate(struct bio *bio) { struct bio_vec *bvec; struct bvec_iter_all iter_all; ASSERT(!bio_flagged(bio, BIO_CLONED)); bio_for_each_segment_all(bvec, bio, iter_all) SetPageUptodate(bvec->bv_page); } /* * end io for the read phase of the rmw cycle. All the bios here are physical * stripe bios we've read from the disk so we can recalculate the parity of the * stripe. * * This will usually kick off finish_rmw once all the bios are read in, but it * may trigger parity reconstruction if we had any errors along the way */ static void raid_rmw_end_io(struct bio *bio) { struct btrfs_raid_bio *rbio = bio->bi_private; if (bio->bi_status) fail_bio_stripe(rbio, bio); else set_bio_pages_uptodate(bio); bio_put(bio); if (!atomic_dec_and_test(&rbio->stripes_pending)) return; if (atomic_read(&rbio->error) > rbio->bbio->max_errors) goto cleanup; /* * this will normally call finish_rmw to start our write * but if there are any failed stripes we'll reconstruct * from parity first */ validate_rbio_for_rmw(rbio); return; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); } /* * the stripe must be locked by the caller. It will * unlock after all the writes are done */ static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio) { int bios_to_read = 0; struct bio_list bio_list; int ret; int pagenr; int stripe; struct bio *bio; bio_list_init(&bio_list); ret = alloc_rbio_pages(rbio); if (ret) goto cleanup; index_rbio_pages(rbio); atomic_set(&rbio->error, 0); /* * build a list of bios to read all the missing parts of this * stripe */ for (stripe = 0; stripe < rbio->nr_data; stripe++) { for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { struct page *page; /* * we want to find all the pages missing from * the rbio and read them from the disk. If * page_in_rbio finds a page in the bio list * we don't need to read it off the stripe. */ page = page_in_rbio(rbio, stripe, pagenr, 1); if (page) continue; page = rbio_stripe_page(rbio, stripe, pagenr); /* * the bio cache may have handed us an uptodate * page. If so, be happy and use it */ if (PageUptodate(page)) continue; ret = rbio_add_io_page(rbio, &bio_list, page, stripe, pagenr, rbio->stripe_len); if (ret) goto cleanup; } } bios_to_read = bio_list_size(&bio_list); if (!bios_to_read) { /* * this can happen if others have merged with * us, it means there is nothing left to read. * But if there are missing devices it may not be * safe to do the full stripe write yet. */ goto finish; } /* * the bbio may be freed once we submit the last bio. Make sure * not to touch it after that */ atomic_set(&rbio->stripes_pending, bios_to_read); while (1) { bio = bio_list_pop(&bio_list); if (!bio) break; bio->bi_private = rbio; bio->bi_end_io = raid_rmw_end_io; bio->bi_opf = REQ_OP_READ; btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56); submit_bio(bio); } /* the actual write will happen once the reads are done */ return 0; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); while ((bio = bio_list_pop(&bio_list))) bio_put(bio); return -EIO; finish: validate_rbio_for_rmw(rbio); return 0; } /* * if the upper layers pass in a full stripe, we thank them by only allocating * enough pages to hold the parity, and sending it all down quickly. */ static int full_stripe_write(struct btrfs_raid_bio *rbio) { int ret; ret = alloc_rbio_parity_pages(rbio); if (ret) { __free_raid_bio(rbio); return ret; } ret = lock_stripe_add(rbio); if (ret == 0) finish_rmw(rbio); return 0; } /* * partial stripe writes get handed over to async helpers. * We're really hoping to merge a few more writes into this * rbio before calculating new parity */ static int partial_stripe_write(struct btrfs_raid_bio *rbio) { int ret; ret = lock_stripe_add(rbio); if (ret == 0) start_async_work(rbio, rmw_work); return 0; } /* * sometimes while we were reading from the drive to * recalculate parity, enough new bios come into create * a full stripe. So we do a check here to see if we can * go directly to finish_rmw */ static int __raid56_parity_write(struct btrfs_raid_bio *rbio) { /* head off into rmw land if we don't have a full stripe */ if (!rbio_is_full(rbio)) return partial_stripe_write(rbio); return full_stripe_write(rbio); } /* * We use plugging call backs to collect full stripes. * Any time we get a partial stripe write while plugged * we collect it into a list. When the unplug comes down, * we sort the list by logical block number and merge * everything we can into the same rbios */ struct btrfs_plug_cb { struct blk_plug_cb cb; struct btrfs_fs_info *info; struct list_head rbio_list; struct btrfs_work work; }; /* * rbios on the plug list are sorted for easier merging. */ static int plug_cmp(void *priv, struct list_head *a, struct list_head *b) { struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio, plug_list); struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio, plug_list); u64 a_sector = ra->bio_list.head->bi_iter.bi_sector; u64 b_sector = rb->bio_list.head->bi_iter.bi_sector; if (a_sector < b_sector) return -1; if (a_sector > b_sector) return 1; return 0; } static void run_plug(struct btrfs_plug_cb *plug) { struct btrfs_raid_bio *cur; struct btrfs_raid_bio *last = NULL; /* * sort our plug list then try to merge * everything we can in hopes of creating full * stripes. */ list_sort(NULL, &plug->rbio_list, plug_cmp); while (!list_empty(&plug->rbio_list)) { cur = list_entry(plug->rbio_list.next, struct btrfs_raid_bio, plug_list); list_del_init(&cur->plug_list); if (rbio_is_full(cur)) { int ret; /* we have a full stripe, send it down */ ret = full_stripe_write(cur); BUG_ON(ret); continue; } if (last) { if (rbio_can_merge(last, cur)) { merge_rbio(last, cur); __free_raid_bio(cur); continue; } __raid56_parity_write(last); } last = cur; } if (last) { __raid56_parity_write(last); } kfree(plug); } /* * if the unplug comes from schedule, we have to push the * work off to a helper thread */ static void unplug_work(struct btrfs_work *work) { struct btrfs_plug_cb *plug; plug = container_of(work, struct btrfs_plug_cb, work); run_plug(plug); } static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule) { struct btrfs_plug_cb *plug; plug = container_of(cb, struct btrfs_plug_cb, cb); if (from_schedule) { btrfs_init_work(&plug->work, unplug_work, NULL, NULL); btrfs_queue_work(plug->info->rmw_workers, &plug->work); return; } run_plug(plug); } /* * our main entry point for writes from the rest of the FS. */ int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len) { struct btrfs_raid_bio *rbio; struct btrfs_plug_cb *plug = NULL; struct blk_plug_cb *cb; int ret; rbio = alloc_rbio(fs_info, bbio, stripe_len); if (IS_ERR(rbio)) { btrfs_put_bbio(bbio); return PTR_ERR(rbio); } bio_list_add(&rbio->bio_list, bio); rbio->bio_list_bytes = bio->bi_iter.bi_size; rbio->operation = BTRFS_RBIO_WRITE; btrfs_bio_counter_inc_noblocked(fs_info); rbio->generic_bio_cnt = 1; /* * don't plug on full rbios, just get them out the door * as quickly as we can */ if (rbio_is_full(rbio)) { ret = full_stripe_write(rbio); if (ret) btrfs_bio_counter_dec(fs_info); return ret; } cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug)); if (cb) { plug = container_of(cb, struct btrfs_plug_cb, cb); if (!plug->info) { plug->info = fs_info; INIT_LIST_HEAD(&plug->rbio_list); } list_add_tail(&rbio->plug_list, &plug->rbio_list); ret = 0; } else { ret = __raid56_parity_write(rbio); if (ret) btrfs_bio_counter_dec(fs_info); } return ret; } /* * all parity reconstruction happens here. We've read in everything * we can find from the drives and this does the heavy lifting of * sorting the good from the bad. */ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) { int pagenr, stripe; void **pointers; int faila = -1, failb = -1; struct page *page; blk_status_t err; int i; pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS); if (!pointers) { err = BLK_STS_RESOURCE; goto cleanup_io; } faila = rbio->faila; failb = rbio->failb; if (rbio->operation == BTRFS_RBIO_READ_REBUILD || rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { spin_lock_irq(&rbio->bio_list_lock); set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); spin_unlock_irq(&rbio->bio_list_lock); } index_rbio_pages(rbio); for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { /* * Now we just use bitmap to mark the horizontal stripes in * which we have data when doing parity scrub. */ if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB && !test_bit(pagenr, rbio->dbitmap)) continue; /* setup our array of pointers with pages * from each stripe */ for (stripe = 0; stripe < rbio->real_stripes; stripe++) { /* * if we're rebuilding a read, we have to use * pages from the bio list */ if ((rbio->operation == BTRFS_RBIO_READ_REBUILD || rbio->operation == BTRFS_RBIO_REBUILD_MISSING) && (stripe == faila || stripe == failb)) { page = page_in_rbio(rbio, stripe, pagenr, 0); } else { page = rbio_stripe_page(rbio, stripe, pagenr); } pointers[stripe] = kmap(page); } /* all raid6 handling here */ if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) { /* * single failure, rebuild from parity raid5 * style */ if (failb < 0) { if (faila == rbio->nr_data) { /* * Just the P stripe has failed, without * a bad data or Q stripe. * TODO, we should redo the xor here. */ err = BLK_STS_IOERR; goto cleanup; } /* * a single failure in raid6 is rebuilt * in the pstripe code below */ goto pstripe; } /* make sure our ps and qs are in order */ if (faila > failb) { int tmp = failb; failb = faila; faila = tmp; } /* if the q stripe is failed, do a pstripe reconstruction * from the xors. * If both the q stripe and the P stripe are failed, we're * here due to a crc mismatch and we can't give them the * data they want */ if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) { if (rbio->bbio->raid_map[faila] == RAID5_P_STRIPE) { err = BLK_STS_IOERR; goto cleanup; } /* * otherwise we have one bad data stripe and * a good P stripe. raid5! */ goto pstripe; } if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) { raid6_datap_recov(rbio->real_stripes, PAGE_SIZE, faila, pointers); } else { raid6_2data_recov(rbio->real_stripes, PAGE_SIZE, faila, failb, pointers); } } else { void *p; /* rebuild from P stripe here (raid5 or raid6) */ BUG_ON(failb != -1); pstripe: /* Copy parity block into failed block to start with */ copy_page(pointers[faila], pointers[rbio->nr_data]); /* rearrange the pointer array */ p = pointers[faila]; for (stripe = faila; stripe < rbio->nr_data - 1; stripe++) pointers[stripe] = pointers[stripe + 1]; pointers[rbio->nr_data - 1] = p; /* xor in the rest */ run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE); } /* if we're doing this rebuild as part of an rmw, go through * and set all of our private rbio pages in the * failed stripes as uptodate. This way finish_rmw will * know they can be trusted. If this was a read reconstruction, * other endio functions will fiddle the uptodate bits */ if (rbio->operation == BTRFS_RBIO_WRITE) { for (i = 0; i < rbio->stripe_npages; i++) { if (faila != -1) { page = rbio_stripe_page(rbio, faila, i); SetPageUptodate(page); } if (failb != -1) { page = rbio_stripe_page(rbio, failb, i); SetPageUptodate(page); } } } for (stripe = 0; stripe < rbio->real_stripes; stripe++) { /* * if we're rebuilding a read, we have to use * pages from the bio list */ if ((rbio->operation == BTRFS_RBIO_READ_REBUILD || rbio->operation == BTRFS_RBIO_REBUILD_MISSING) && (stripe == faila || stripe == failb)) { page = page_in_rbio(rbio, stripe, pagenr, 0); } else { page = rbio_stripe_page(rbio, stripe, pagenr); } kunmap(page); } } err = BLK_STS_OK; cleanup: kfree(pointers); cleanup_io: /* * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a * valid rbio which is consistent with ondisk content, thus such a * valid rbio can be cached to avoid further disk reads. */ if (rbio->operation == BTRFS_RBIO_READ_REBUILD || rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { /* * - In case of two failures, where rbio->failb != -1: * * Do not cache this rbio since the above read reconstruction * (raid6_datap_recov() or raid6_2data_recov()) may have * changed some content of stripes which are not identical to * on-disk content any more, otherwise, a later write/recover * may steal stripe_pages from this rbio and end up with * corruptions or rebuild failures. * * - In case of single failure, where rbio->failb == -1: * * Cache this rbio iff the above read reconstruction is * executed without problems. */ if (err == BLK_STS_OK && rbio->failb < 0) cache_rbio_pages(rbio); else clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); rbio_orig_end_io(rbio, err); } else if (err == BLK_STS_OK) { rbio->faila = -1; rbio->failb = -1; if (rbio->operation == BTRFS_RBIO_WRITE) finish_rmw(rbio); else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) finish_parity_scrub(rbio, 0); else BUG(); } else { rbio_orig_end_io(rbio, err); } } /* * This is called only for stripes we've read from disk to * reconstruct the parity. */ static void raid_recover_end_io(struct bio *bio) { struct btrfs_raid_bio *rbio = bio->bi_private; /* * we only read stripe pages off the disk, set them * up to date if there were no errors */ if (bio->bi_status) fail_bio_stripe(rbio, bio); else set_bio_pages_uptodate(bio); bio_put(bio); if (!atomic_dec_and_test(&rbio->stripes_pending)) return; if (atomic_read(&rbio->error) > rbio->bbio->max_errors) rbio_orig_end_io(rbio, BLK_STS_IOERR); else __raid_recover_end_io(rbio); } /* * reads everything we need off the disk to reconstruct * the parity. endio handlers trigger final reconstruction * when the IO is done. * * This is used both for reads from the higher layers and for * parity construction required to finish a rmw cycle. */ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio) { int bios_to_read = 0; struct bio_list bio_list; int ret; int pagenr; int stripe; struct bio *bio; bio_list_init(&bio_list); ret = alloc_rbio_pages(rbio); if (ret) goto cleanup; atomic_set(&rbio->error, 0); /* * read everything that hasn't failed. Thanks to the * stripe cache, it is possible that some or all of these * pages are going to be uptodate. */ for (stripe = 0; stripe < rbio->real_stripes; stripe++) { if (rbio->faila == stripe || rbio->failb == stripe) { atomic_inc(&rbio->error); continue; } for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) { struct page *p; /* * the rmw code may have already read this * page in */ p = rbio_stripe_page(rbio, stripe, pagenr); if (PageUptodate(p)) continue; ret = rbio_add_io_page(rbio, &bio_list, rbio_stripe_page(rbio, stripe, pagenr), stripe, pagenr, rbio->stripe_len); if (ret < 0) goto cleanup; } } bios_to_read = bio_list_size(&bio_list); if (!bios_to_read) { /* * we might have no bios to read just because the pages * were up to date, or we might have no bios to read because * the devices were gone. */ if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) { __raid_recover_end_io(rbio); goto out; } else { goto cleanup; } } /* * the bbio may be freed once we submit the last bio. Make sure * not to touch it after that */ atomic_set(&rbio->stripes_pending, bios_to_read); while (1) { bio = bio_list_pop(&bio_list); if (!bio) break; bio->bi_private = rbio; bio->bi_end_io = raid_recover_end_io; bio->bi_opf = REQ_OP_READ; btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56); submit_bio(bio); } out: return 0; cleanup: if (rbio->operation == BTRFS_RBIO_READ_REBUILD || rbio->operation == BTRFS_RBIO_REBUILD_MISSING) rbio_orig_end_io(rbio, BLK_STS_IOERR); while ((bio = bio_list_pop(&bio_list))) bio_put(bio); return -EIO; } /* * the main entry point for reads from the higher layers. This * is really only called when the normal read path had a failure, * so we assume the bio they send down corresponds to a failed part * of the drive. */ int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len, int mirror_num, int generic_io) { struct btrfs_raid_bio *rbio; int ret; if (generic_io) { ASSERT(bbio->mirror_num == mirror_num); btrfs_io_bio(bio)->mirror_num = mirror_num; } rbio = alloc_rbio(fs_info, bbio, stripe_len); if (IS_ERR(rbio)) { if (generic_io) btrfs_put_bbio(bbio); return PTR_ERR(rbio); } rbio->operation = BTRFS_RBIO_READ_REBUILD; bio_list_add(&rbio->bio_list, bio); rbio->bio_list_bytes = bio->bi_iter.bi_size; rbio->faila = find_logical_bio_stripe(rbio, bio); if (rbio->faila == -1) { btrfs_warn(fs_info, "%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bbio has map_type %llu)", __func__, (u64)bio->bi_iter.bi_sector << 9, (u64)bio->bi_iter.bi_size, bbio->map_type); if (generic_io) btrfs_put_bbio(bbio); kfree(rbio); return -EIO; } if (generic_io) { btrfs_bio_counter_inc_noblocked(fs_info); rbio->generic_bio_cnt = 1; } else { btrfs_get_bbio(bbio); } /* * Loop retry: * for 'mirror == 2', reconstruct from all other stripes. * for 'mirror_num > 2', select a stripe to fail on every retry. */ if (mirror_num > 2) { /* * 'mirror == 3' is to fail the p stripe and * reconstruct from the q stripe. 'mirror > 3' is to * fail a data stripe and reconstruct from p+q stripe. */ rbio->failb = rbio->real_stripes - (mirror_num - 1); ASSERT(rbio->failb > 0); if (rbio->failb <= rbio->faila) rbio->failb--; } ret = lock_stripe_add(rbio); /* * __raid56_parity_recover will end the bio with * any errors it hits. We don't want to return * its error value up the stack because our caller * will end up calling bio_endio with any nonzero * return */ if (ret == 0) __raid56_parity_recover(rbio); /* * our rbio has been added to the list of * rbios that will be handled after the * currently lock owner is done */ return 0; } static void rmw_work(struct btrfs_work *work) { struct btrfs_raid_bio *rbio; rbio = container_of(work, struct btrfs_raid_bio, work); raid56_rmw_stripe(rbio); } static void read_rebuild_work(struct btrfs_work *work) { struct btrfs_raid_bio *rbio; rbio = container_of(work, struct btrfs_raid_bio, work); __raid56_parity_recover(rbio); } /* * The following code is used to scrub/replace the parity stripe * * Caller must have already increased bio_counter for getting @bbio. * * Note: We need make sure all the pages that add into the scrub/replace * raid bio are correct and not be changed during the scrub/replace. That * is those pages just hold metadata or file data with checksum. */ struct btrfs_raid_bio * raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len, struct btrfs_device *scrub_dev, unsigned long *dbitmap, int stripe_nsectors) { struct btrfs_raid_bio *rbio; int i; rbio = alloc_rbio(fs_info, bbio, stripe_len); if (IS_ERR(rbio)) return NULL; bio_list_add(&rbio->bio_list, bio); /* * This is a special bio which is used to hold the completion handler * and make the scrub rbio is similar to the other types */ ASSERT(!bio->bi_iter.bi_size); rbio->operation = BTRFS_RBIO_PARITY_SCRUB; /* * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted * to the end position, so this search can start from the first parity * stripe. */ for (i = rbio->nr_data; i < rbio->real_stripes; i++) { if (bbio->stripes[i].dev == scrub_dev) { rbio->scrubp = i; break; } } ASSERT(i < rbio->real_stripes); /* Now we just support the sectorsize equals to page size */ ASSERT(fs_info->sectorsize == PAGE_SIZE); ASSERT(rbio->stripe_npages == stripe_nsectors); bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors); /* * We have already increased bio_counter when getting bbio, record it * so we can free it at rbio_orig_end_io(). */ rbio->generic_bio_cnt = 1; return rbio; } /* Used for both parity scrub and missing. */ void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page, u64 logical) { int stripe_offset; int index; ASSERT(logical >= rbio->bbio->raid_map[0]); ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] + rbio->stripe_len * rbio->nr_data); stripe_offset = (int)(logical - rbio->bbio->raid_map[0]); index = stripe_offset >> PAGE_SHIFT; rbio->bio_pages[index] = page; } /* * We just scrub the parity that we have correct data on the same horizontal, * so we needn't allocate all pages for all the stripes. */ static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio) { int i; int bit; int index; struct page *page; for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) { for (i = 0; i < rbio->real_stripes; i++) { index = i * rbio->stripe_npages + bit; if (rbio->stripe_pages[index]) continue; page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!page) return -ENOMEM; rbio->stripe_pages[index] = page; } } return 0; } static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, int need_check) { struct btrfs_bio *bbio = rbio->bbio; void **pointers = rbio->finish_pointers; unsigned long *pbitmap = rbio->finish_pbitmap; int nr_data = rbio->nr_data; int stripe; int pagenr; bool has_qstripe; struct page *p_page = NULL; struct page *q_page = NULL; struct bio_list bio_list; struct bio *bio; int is_replace = 0; int ret; bio_list_init(&bio_list); if (rbio->real_stripes - rbio->nr_data == 1) has_qstripe = false; else if (rbio->real_stripes - rbio->nr_data == 2) has_qstripe = true; else BUG(); if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) { is_replace = 1; bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages); } /* * Because the higher layers(scrubber) are unlikely to * use this area of the disk again soon, so don't cache * it. */ clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); if (!need_check) goto writeback; p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!p_page) goto cleanup; SetPageUptodate(p_page); if (has_qstripe) { q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!q_page) { __free_page(p_page); goto cleanup; } SetPageUptodate(q_page); } atomic_set(&rbio->error, 0); for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) { struct page *p; void *parity; /* first collect one page from each data stripe */ for (stripe = 0; stripe < nr_data; stripe++) { p = page_in_rbio(rbio, stripe, pagenr, 0); pointers[stripe] = kmap(p); } /* then add the parity stripe */ pointers[stripe++] = kmap(p_page); if (has_qstripe) { /* * raid6, add the qstripe and call the * library function to fill in our p/q */ pointers[stripe++] = kmap(q_page); raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE, pointers); } else { /* raid5 */ copy_page(pointers[nr_data], pointers[0]); run_xor(pointers + 1, nr_data - 1, PAGE_SIZE); } /* Check scrubbing parity and repair it */ p = rbio_stripe_page(rbio, rbio->scrubp, pagenr); parity = kmap(p); if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE)) copy_page(parity, pointers[rbio->scrubp]); else /* Parity is right, needn't writeback */ bitmap_clear(rbio->dbitmap, pagenr, 1); kunmap(p); for (stripe = 0; stripe < nr_data; stripe++) kunmap(page_in_rbio(rbio, stripe, pagenr, 0)); kunmap(p_page); } __free_page(p_page); if (q_page) __free_page(q_page); writeback: /* * time to start writing. Make bios for everything from the * higher layers (the bio_list in our rbio) and our p/q. Ignore * everything else. */ for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) { struct page *page; page = rbio_stripe_page(rbio, rbio->scrubp, pagenr); ret = rbio_add_io_page(rbio, &bio_list, page, rbio->scrubp, pagenr, rbio->stripe_len); if (ret) goto cleanup; } if (!is_replace) goto submit_write; for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) { struct page *page; page = rbio_stripe_page(rbio, rbio->scrubp, pagenr); ret = rbio_add_io_page(rbio, &bio_list, page, bbio->tgtdev_map[rbio->scrubp], pagenr, rbio->stripe_len); if (ret) goto cleanup; } submit_write: nr_data = bio_list_size(&bio_list); if (!nr_data) { /* Every parity is right */ rbio_orig_end_io(rbio, BLK_STS_OK); return; } atomic_set(&rbio->stripes_pending, nr_data); while (1) { bio = bio_list_pop(&bio_list); if (!bio) break; bio->bi_private = rbio; bio->bi_end_io = raid_write_end_io; bio->bi_opf = REQ_OP_WRITE; submit_bio(bio); } return; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); while ((bio = bio_list_pop(&bio_list))) bio_put(bio); } static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe) { if (stripe >= 0 && stripe < rbio->nr_data) return 1; return 0; } /* * While we're doing the parity check and repair, we could have errors * in reading pages off the disk. This checks for errors and if we're * not able to read the page it'll trigger parity reconstruction. The * parity scrub will be finished after we've reconstructed the failed * stripes */ static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio) { if (atomic_read(&rbio->error) > rbio->bbio->max_errors) goto cleanup; if (rbio->faila >= 0 || rbio->failb >= 0) { int dfail = 0, failp = -1; if (is_data_stripe(rbio, rbio->faila)) dfail++; else if (is_parity_stripe(rbio->faila)) failp = rbio->faila; if (is_data_stripe(rbio, rbio->failb)) dfail++; else if (is_parity_stripe(rbio->failb)) failp = rbio->failb; /* * Because we can not use a scrubbing parity to repair * the data, so the capability of the repair is declined. * (In the case of RAID5, we can not repair anything) */ if (dfail > rbio->bbio->max_errors - 1) goto cleanup; /* * If all data is good, only parity is correctly, just * repair the parity. */ if (dfail == 0) { finish_parity_scrub(rbio, 0); return; } /* * Here means we got one corrupted data stripe and one * corrupted parity on RAID6, if the corrupted parity * is scrubbing parity, luckily, use the other one to repair * the data, or we can not repair the data stripe. */ if (failp != rbio->scrubp) goto cleanup; __raid_recover_end_io(rbio); } else { finish_parity_scrub(rbio, 1); } return; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); } /* * end io for the read phase of the rmw cycle. All the bios here are physical * stripe bios we've read from the disk so we can recalculate the parity of the * stripe. * * This will usually kick off finish_rmw once all the bios are read in, but it * may trigger parity reconstruction if we had any errors along the way */ static void raid56_parity_scrub_end_io(struct bio *bio) { struct btrfs_raid_bio *rbio = bio->bi_private; if (bio->bi_status) fail_bio_stripe(rbio, bio); else set_bio_pages_uptodate(bio); bio_put(bio); if (!atomic_dec_and_test(&rbio->stripes_pending)) return; /* * this will normally call finish_rmw to start our write * but if there are any failed stripes we'll reconstruct * from parity first */ validate_rbio_for_parity_scrub(rbio); } static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) { int bios_to_read = 0; struct bio_list bio_list; int ret; int pagenr; int stripe; struct bio *bio; bio_list_init(&bio_list); ret = alloc_rbio_essential_pages(rbio); if (ret) goto cleanup; atomic_set(&rbio->error, 0); /* * build a list of bios to read all the missing parts of this * stripe */ for (stripe = 0; stripe < rbio->real_stripes; stripe++) { for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) { struct page *page; /* * we want to find all the pages missing from * the rbio and read them from the disk. If * page_in_rbio finds a page in the bio list * we don't need to read it off the stripe. */ page = page_in_rbio(rbio, stripe, pagenr, 1); if (page) continue; page = rbio_stripe_page(rbio, stripe, pagenr); /* * the bio cache may have handed us an uptodate * page. If so, be happy and use it */ if (PageUptodate(page)) continue; ret = rbio_add_io_page(rbio, &bio_list, page, stripe, pagenr, rbio->stripe_len); if (ret) goto cleanup; } } bios_to_read = bio_list_size(&bio_list); if (!bios_to_read) { /* * this can happen if others have merged with * us, it means there is nothing left to read. * But if there are missing devices it may not be * safe to do the full stripe write yet. */ goto finish; } /* * the bbio may be freed once we submit the last bio. Make sure * not to touch it after that */ atomic_set(&rbio->stripes_pending, bios_to_read); while (1) { bio = bio_list_pop(&bio_list); if (!bio) break; bio->bi_private = rbio; bio->bi_end_io = raid56_parity_scrub_end_io; bio->bi_opf = REQ_OP_READ; btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56); submit_bio(bio); } /* the actual write will happen once the reads are done */ return; cleanup: rbio_orig_end_io(rbio, BLK_STS_IOERR); while ((bio = bio_list_pop(&bio_list))) bio_put(bio); return; finish: validate_rbio_for_parity_scrub(rbio); } static void scrub_parity_work(struct btrfs_work *work) { struct btrfs_raid_bio *rbio; rbio = container_of(work, struct btrfs_raid_bio, work); raid56_parity_scrub_stripe(rbio); } void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio) { if (!lock_stripe_add(rbio)) start_async_work(rbio, scrub_parity_work); } /* The following code is used for dev replace of a missing RAID 5/6 device. */ struct btrfs_raid_bio * raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 length) { struct btrfs_raid_bio *rbio; rbio = alloc_rbio(fs_info, bbio, length); if (IS_ERR(rbio)) return NULL; rbio->operation = BTRFS_RBIO_REBUILD_MISSING; bio_list_add(&rbio->bio_list, bio); /* * This is a special bio which is used to hold the completion handler * and make the scrub rbio is similar to the other types */ ASSERT(!bio->bi_iter.bi_size); rbio->faila = find_logical_bio_stripe(rbio, bio); if (rbio->faila == -1) { BUG(); kfree(rbio); return NULL; } /* * When we get bbio, we have already increased bio_counter, record it * so we can free it at rbio_orig_end_io() */ rbio->generic_bio_cnt = 1; return rbio; } void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio) { if (!lock_stripe_add(rbio)) start_async_work(rbio, read_rebuild_work); }