/* * Copyright (C) 2011, 2012 STRATO. 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 "ctree.h" #include "volumes.h" #include "disk-io.h" #include "ordered-data.h" #include "transaction.h" #include "backref.h" #include "extent_io.h" #include "dev-replace.h" #include "check-integrity.h" #include "rcu-string.h" #include "raid56.h" /* * This is only the first step towards a full-features scrub. It reads all * extent and super block and verifies the checksums. In case a bad checksum * is found or the extent cannot be read, good data will be written back if * any can be found. * * Future enhancements: * - In case an unrepairable extent is encountered, track which files are * affected and report them * - track and record media errors, throw out bad devices * - add a mode to also read unallocated space */ struct scrub_block; struct scrub_ctx; /* * the following three values only influence the performance. * The last one configures the number of parallel and outstanding I/O * operations. The first two values configure an upper limit for the number * of (dynamically allocated) pages that are added to a bio. */ #define SCRUB_PAGES_PER_RD_BIO 32 /* 128k per bio */ #define SCRUB_PAGES_PER_WR_BIO 32 /* 128k per bio */ #define SCRUB_BIOS_PER_SCTX 64 /* 8MB per device in flight */ /* * the following value times PAGE_SIZE needs to be large enough to match the * largest node/leaf/sector size that shall be supported. * Values larger than BTRFS_STRIPE_LEN are not supported. */ #define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */ struct scrub_page { struct scrub_block *sblock; struct page *page; struct btrfs_device *dev; u64 flags; /* extent flags */ u64 generation; u64 logical; u64 physical; u64 physical_for_dev_replace; atomic_t ref_count; struct { unsigned int mirror_num:8; unsigned int have_csum:1; unsigned int io_error:1; }; u8 csum[BTRFS_CSUM_SIZE]; }; struct scrub_bio { int index; struct scrub_ctx *sctx; struct btrfs_device *dev; struct bio *bio; int err; u64 logical; u64 physical; #if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO struct scrub_page *pagev[SCRUB_PAGES_PER_WR_BIO]; #else struct scrub_page *pagev[SCRUB_PAGES_PER_RD_BIO]; #endif int page_count; int next_free; struct btrfs_work work; }; struct scrub_block { struct scrub_page *pagev[SCRUB_MAX_PAGES_PER_BLOCK]; int page_count; atomic_t outstanding_pages; atomic_t ref_count; /* free mem on transition to zero */ struct scrub_ctx *sctx; struct { unsigned int header_error:1; unsigned int checksum_error:1; unsigned int no_io_error_seen:1; unsigned int generation_error:1; /* also sets header_error */ }; }; struct scrub_wr_ctx { struct scrub_bio *wr_curr_bio; struct btrfs_device *tgtdev; int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */ atomic_t flush_all_writes; struct mutex wr_lock; }; struct scrub_ctx { struct scrub_bio *bios[SCRUB_BIOS_PER_SCTX]; struct btrfs_root *dev_root; int first_free; int curr; atomic_t bios_in_flight; atomic_t workers_pending; spinlock_t list_lock; wait_queue_head_t list_wait; u16 csum_size; struct list_head csum_list; atomic_t cancel_req; int readonly; int pages_per_rd_bio; u32 sectorsize; u32 nodesize; u32 leafsize; int is_dev_replace; struct scrub_wr_ctx wr_ctx; /* * statistics */ struct btrfs_scrub_progress stat; spinlock_t stat_lock; }; struct scrub_fixup_nodatasum { struct scrub_ctx *sctx; struct btrfs_device *dev; u64 logical; struct btrfs_root *root; struct btrfs_work work; int mirror_num; }; struct scrub_copy_nocow_ctx { struct scrub_ctx *sctx; u64 logical; u64 len; int mirror_num; u64 physical_for_dev_replace; struct btrfs_work work; }; struct scrub_warning { struct btrfs_path *path; u64 extent_item_size; char *scratch_buf; char *msg_buf; const char *errstr; sector_t sector; u64 logical; struct btrfs_device *dev; int msg_bufsize; int scratch_bufsize; }; static void scrub_pending_bio_inc(struct scrub_ctx *sctx); static void scrub_pending_bio_dec(struct scrub_ctx *sctx); static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx); static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx); static int scrub_handle_errored_block(struct scrub_block *sblock_to_check); static int scrub_setup_recheck_block(struct scrub_ctx *sctx, struct btrfs_fs_info *fs_info, struct scrub_block *original_sblock, u64 length, u64 logical, struct scrub_block *sblocks_for_recheck); static void scrub_recheck_block(struct btrfs_fs_info *fs_info, struct scrub_block *sblock, int is_metadata, int have_csum, u8 *csum, u64 generation, u16 csum_size); static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info, struct scrub_block *sblock, int is_metadata, int have_csum, const u8 *csum, u64 generation, u16 csum_size); static void scrub_complete_bio_end_io(struct bio *bio, int err); static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad, struct scrub_block *sblock_good, int force_write); static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad, struct scrub_block *sblock_good, int page_num, int force_write); static void scrub_write_block_to_dev_replace(struct scrub_block *sblock); static int scrub_write_page_to_dev_replace(struct scrub_block *sblock, int page_num); static int scrub_checksum_data(struct scrub_block *sblock); static int scrub_checksum_tree_block(struct scrub_block *sblock); static int scrub_checksum_super(struct scrub_block *sblock); static void scrub_block_get(struct scrub_block *sblock); static void scrub_block_put(struct scrub_block *sblock); static void scrub_page_get(struct scrub_page *spage); static void scrub_page_put(struct scrub_page *spage); static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx, struct scrub_page *spage); static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len, u64 physical, struct btrfs_device *dev, u64 flags, u64 gen, int mirror_num, u8 *csum, int force, u64 physical_for_dev_replace); static void scrub_bio_end_io(struct bio *bio, int err); static void scrub_bio_end_io_worker(struct btrfs_work *work); static void scrub_block_complete(struct scrub_block *sblock); static void scrub_remap_extent(struct btrfs_fs_info *fs_info, u64 extent_logical, u64 extent_len, u64 *extent_physical, struct btrfs_device **extent_dev, int *extent_mirror_num); static int scrub_setup_wr_ctx(struct scrub_ctx *sctx, struct scrub_wr_ctx *wr_ctx, struct btrfs_fs_info *fs_info, struct btrfs_device *dev, int is_dev_replace); static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx); static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx, struct scrub_page *spage); static void scrub_wr_submit(struct scrub_ctx *sctx); static void scrub_wr_bio_end_io(struct bio *bio, int err); static void scrub_wr_bio_end_io_worker(struct btrfs_work *work); static int write_page_nocow(struct scrub_ctx *sctx, u64 physical_for_dev_replace, struct page *page); static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx); static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len, int mirror_num, u64 physical_for_dev_replace); static void copy_nocow_pages_worker(struct btrfs_work *work); static void scrub_pending_bio_inc(struct scrub_ctx *sctx) { atomic_inc(&sctx->bios_in_flight); } static void scrub_pending_bio_dec(struct scrub_ctx *sctx) { atomic_dec(&sctx->bios_in_flight); wake_up(&sctx->list_wait); } /* * used for workers that require transaction commits (i.e., for the * NOCOW case) */ static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx) { struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info; /* * increment scrubs_running to prevent cancel requests from * completing as long as a worker is running. we must also * increment scrubs_paused to prevent deadlocking on pause * requests used for transactions commits (as the worker uses a * transaction context). it is safe to regard the worker * as paused for all matters practical. effectively, we only * avoid cancellation requests from completing. */ mutex_lock(&fs_info->scrub_lock); atomic_inc(&fs_info->scrubs_running); atomic_inc(&fs_info->scrubs_paused); mutex_unlock(&fs_info->scrub_lock); atomic_inc(&sctx->workers_pending); } /* used for workers that require transaction commits */ static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx) { struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info; /* * see scrub_pending_trans_workers_inc() why we're pretending * to be paused in the scrub counters */ mutex_lock(&fs_info->scrub_lock); atomic_dec(&fs_info->scrubs_running); atomic_dec(&fs_info->scrubs_paused); mutex_unlock(&fs_info->scrub_lock); atomic_dec(&sctx->workers_pending); wake_up(&fs_info->scrub_pause_wait); wake_up(&sctx->list_wait); } static void scrub_free_csums(struct scrub_ctx *sctx) { while (!list_empty(&sctx->csum_list)) { struct btrfs_ordered_sum *sum; sum = list_first_entry(&sctx->csum_list, struct btrfs_ordered_sum, list); list_del(&sum->list); kfree(sum); } } static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx) { int i; if (!sctx) return; scrub_free_wr_ctx(&sctx->wr_ctx); /* this can happen when scrub is cancelled */ if (sctx->curr != -1) { struct scrub_bio *sbio = sctx->bios[sctx->curr]; for (i = 0; i < sbio->page_count; i++) { WARN_ON(!sbio->pagev[i]->page); scrub_block_put(sbio->pagev[i]->sblock); } bio_put(sbio->bio); } for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) { struct scrub_bio *sbio = sctx->bios[i]; if (!sbio) break; kfree(sbio); } scrub_free_csums(sctx); kfree(sctx); } static noinline_for_stack struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace) { struct scrub_ctx *sctx; int i; struct btrfs_fs_info *fs_info = dev->dev_root->fs_info; int pages_per_rd_bio; int ret; /* * the setting of pages_per_rd_bio is correct for scrub but might * be wrong for the dev_replace code where we might read from * different devices in the initial huge bios. However, that * code is able to correctly handle the case when adding a page * to a bio fails. */ if (dev->bdev) pages_per_rd_bio = min_t(int, SCRUB_PAGES_PER_RD_BIO, bio_get_nr_vecs(dev->bdev)); else pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO; sctx = kzalloc(sizeof(*sctx), GFP_NOFS); if (!sctx) goto nomem; sctx->is_dev_replace = is_dev_replace; sctx->pages_per_rd_bio = pages_per_rd_bio; sctx->curr = -1; sctx->dev_root = dev->dev_root; for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) { struct scrub_bio *sbio; sbio = kzalloc(sizeof(*sbio), GFP_NOFS); if (!sbio) goto nomem; sctx->bios[i] = sbio; sbio->index = i; sbio->sctx = sctx; sbio->page_count = 0; sbio->work.func = scrub_bio_end_io_worker; if (i != SCRUB_BIOS_PER_SCTX - 1) sctx->bios[i]->next_free = i + 1; else sctx->bios[i]->next_free = -1; } sctx->first_free = 0; sctx->nodesize = dev->dev_root->nodesize; sctx->leafsize = dev->dev_root->leafsize; sctx->sectorsize = dev->dev_root->sectorsize; atomic_set(&sctx->bios_in_flight, 0); atomic_set(&sctx->workers_pending, 0); atomic_set(&sctx->cancel_req, 0); sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy); INIT_LIST_HEAD(&sctx->csum_list); spin_lock_init(&sctx->list_lock); spin_lock_init(&sctx->stat_lock); init_waitqueue_head(&sctx->list_wait); ret = scrub_setup_wr_ctx(sctx, &sctx->wr_ctx, fs_info, fs_info->dev_replace.tgtdev, is_dev_replace); if (ret) { scrub_free_ctx(sctx); return ERR_PTR(ret); } return sctx; nomem: scrub_free_ctx(sctx); return ERR_PTR(-ENOMEM); } static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *warn_ctx) { u64 isize; u32 nlink; int ret; int i; struct extent_buffer *eb; struct btrfs_inode_item *inode_item; struct scrub_warning *swarn = warn_ctx; struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info; struct inode_fs_paths *ipath = NULL; struct btrfs_root *local_root; struct btrfs_key root_key; root_key.objectid = root; root_key.type = BTRFS_ROOT_ITEM_KEY; root_key.offset = (u64)-1; local_root = btrfs_read_fs_root_no_name(fs_info, &root_key); if (IS_ERR(local_root)) { ret = PTR_ERR(local_root); goto err; } ret = inode_item_info(inum, 0, local_root, swarn->path); if (ret) { btrfs_release_path(swarn->path); goto err; } eb = swarn->path->nodes[0]; inode_item = btrfs_item_ptr(eb, swarn->path->slots[0], struct btrfs_inode_item); isize = btrfs_inode_size(eb, inode_item); nlink = btrfs_inode_nlink(eb, inode_item); btrfs_release_path(swarn->path); ipath = init_ipath(4096, local_root, swarn->path); if (IS_ERR(ipath)) { ret = PTR_ERR(ipath); ipath = NULL; goto err; } ret = paths_from_inode(inum, ipath); if (ret < 0) goto err; /* * we deliberately ignore the bit ipath might have been too small to * hold all of the paths here */ for (i = 0; i < ipath->fspath->elem_cnt; ++i) printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev " "%s, sector %llu, root %llu, inode %llu, offset %llu, " "length %llu, links %u (path: %s)\n", swarn->errstr, swarn->logical, rcu_str_deref(swarn->dev->name), (unsigned long long)swarn->sector, root, inum, offset, min(isize - offset, (u64)PAGE_SIZE), nlink, (char *)(unsigned long)ipath->fspath->val[i]); free_ipath(ipath); return 0; err: printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev " "%s, sector %llu, root %llu, inode %llu, offset %llu: path " "resolving failed with ret=%d\n", swarn->errstr, swarn->logical, rcu_str_deref(swarn->dev->name), (unsigned long long)swarn->sector, root, inum, offset, ret); free_ipath(ipath); return 0; } static void scrub_print_warning(const char *errstr, struct scrub_block *sblock) { struct btrfs_device *dev; struct btrfs_fs_info *fs_info; struct btrfs_path *path; struct btrfs_key found_key; struct extent_buffer *eb; struct btrfs_extent_item *ei; struct scrub_warning swarn; unsigned long ptr = 0; u64 extent_item_pos; u64 flags = 0; u64 ref_root; u32 item_size; u8 ref_level; const int bufsize = 4096; int ret; WARN_ON(sblock->page_count < 1); dev = sblock->pagev[0]->dev; fs_info = sblock->sctx->dev_root->fs_info; path = btrfs_alloc_path(); swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS); swarn.msg_buf = kmalloc(bufsize, GFP_NOFS); swarn.sector = (sblock->pagev[0]->physical) >> 9; swarn.logical = sblock->pagev[0]->logical; swarn.errstr = errstr; swarn.dev = NULL; swarn.msg_bufsize = bufsize; swarn.scratch_bufsize = bufsize; if (!path || !swarn.scratch_buf || !swarn.msg_buf) goto out; ret = extent_from_logical(fs_info, swarn.logical, path, &found_key, &flags); if (ret < 0) goto out; extent_item_pos = swarn.logical - found_key.objectid; swarn.extent_item_size = found_key.offset; eb = path->nodes[0]; ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); item_size = btrfs_item_size_nr(eb, path->slots[0]); if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { do { ret = tree_backref_for_extent(&ptr, eb, ei, item_size, &ref_root, &ref_level); printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev %s, " "sector %llu: metadata %s (level %d) in tree " "%llu\n", errstr, swarn.logical, rcu_str_deref(dev->name), (unsigned long long)swarn.sector, ref_level ? "node" : "leaf", ret < 0 ? -1 : ref_level, ret < 0 ? -1 : ref_root); } while (ret != 1); btrfs_release_path(path); } else { btrfs_release_path(path); swarn.path = path; swarn.dev = dev; iterate_extent_inodes(fs_info, found_key.objectid, extent_item_pos, 1, scrub_print_warning_inode, &swarn); } out: btrfs_free_path(path); kfree(swarn.scratch_buf); kfree(swarn.msg_buf); } static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx) { struct page *page = NULL; unsigned long index; struct scrub_fixup_nodatasum *fixup = fixup_ctx; int ret; int corrected = 0; struct btrfs_key key; struct inode *inode = NULL; struct btrfs_fs_info *fs_info; u64 end = offset + PAGE_SIZE - 1; struct btrfs_root *local_root; int srcu_index; key.objectid = root; key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1; fs_info = fixup->root->fs_info; srcu_index = srcu_read_lock(&fs_info->subvol_srcu); local_root = btrfs_read_fs_root_no_name(fs_info, &key); if (IS_ERR(local_root)) { srcu_read_unlock(&fs_info->subvol_srcu, srcu_index); return PTR_ERR(local_root); } key.type = BTRFS_INODE_ITEM_KEY; key.objectid = inum; key.offset = 0; inode = btrfs_iget(fs_info->sb, &key, local_root, NULL); srcu_read_unlock(&fs_info->subvol_srcu, srcu_index); if (IS_ERR(inode)) return PTR_ERR(inode); index = offset >> PAGE_CACHE_SHIFT; page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); if (!page) { ret = -ENOMEM; goto out; } if (PageUptodate(page)) { if (PageDirty(page)) { /* * we need to write the data to the defect sector. the * data that was in that sector is not in memory, * because the page was modified. we must not write the * modified page to that sector. * * TODO: what could be done here: wait for the delalloc * runner to write out that page (might involve * COW) and see whether the sector is still * referenced afterwards. * * For the meantime, we'll treat this error * incorrectable, although there is a chance that a * later scrub will find the bad sector again and that * there's no dirty page in memory, then. */ ret = -EIO; goto out; } fs_info = BTRFS_I(inode)->root->fs_info; ret = repair_io_failure(fs_info, offset, PAGE_SIZE, fixup->logical, page, fixup->mirror_num); unlock_page(page); corrected = !ret; } else { /* * we need to get good data first. the general readpage path * will call repair_io_failure for us, we just have to make * sure we read the bad mirror. */ ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end, EXTENT_DAMAGED, GFP_NOFS); if (ret) { /* set_extent_bits should give proper error */ WARN_ON(ret > 0); if (ret > 0) ret = -EFAULT; goto out; } ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page, btrfs_get_extent, fixup->mirror_num); wait_on_page_locked(page); corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset, end, EXTENT_DAMAGED, 0, NULL); if (!corrected) clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end, EXTENT_DAMAGED, GFP_NOFS); } out: if (page) put_page(page); if (inode) iput(inode); if (ret < 0) return ret; if (ret == 0 && corrected) { /* * we only need to call readpage for one of the inodes belonging * to this extent. so make iterate_extent_inodes stop */ return 1; } return -EIO; } static void scrub_fixup_nodatasum(struct btrfs_work *work) { int ret; struct scrub_fixup_nodatasum *fixup; struct scrub_ctx *sctx; struct btrfs_trans_handle *trans = NULL; struct btrfs_fs_info *fs_info; struct btrfs_path *path; int uncorrectable = 0; fixup = container_of(work, struct scrub_fixup_nodatasum, work); sctx = fixup->sctx; fs_info = fixup->root->fs_info; path = btrfs_alloc_path(); if (!path) { spin_lock(&sctx->stat_lock); ++sctx->stat.malloc_errors; spin_unlock(&sctx->stat_lock); uncorrectable = 1; goto out; } trans = btrfs_join_transaction(fixup->root); if (IS_ERR(trans)) { uncorrectable = 1; goto out; } /* * the idea is to trigger a regular read through the standard path. we * read a page from the (failed) logical address by specifying the * corresponding copynum of the failed sector. thus, that readpage is * expected to fail. * that is the point where on-the-fly error correction will kick in * (once it's finished) and rewrite the failed sector if a good copy * can be found. */ ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info, path, scrub_fixup_readpage, fixup); if (ret < 0) { uncorrectable = 1; goto out; } WARN_ON(ret != 1); spin_lock(&sctx->stat_lock); ++sctx->stat.corrected_errors; spin_unlock(&sctx->stat_lock); out: if (trans && !IS_ERR(trans)) btrfs_end_transaction(trans, fixup->root); if (uncorrectable) { spin_lock(&sctx->stat_lock); ++sctx->stat.uncorrectable_errors; spin_unlock(&sctx->stat_lock); btrfs_dev_replace_stats_inc( &sctx->dev_root->fs_info->dev_replace. num_uncorrectable_read_errors); printk_ratelimited_in_rcu(KERN_ERR "btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n", fixup->logical, rcu_str_deref(fixup->dev->name)); } btrfs_free_path(path); kfree(fixup); scrub_pending_trans_workers_dec(sctx); } /* * scrub_handle_errored_block gets called when either verification of the * pages failed or the bio failed to read, e.g. with EIO. In the latter * case, this function handles all pages in the bio, even though only one * may be bad. * The goal of this function is to repair the errored block by using the * contents of one of the mirrors. */ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check) { struct scrub_ctx *sctx = sblock_to_check->sctx; struct btrfs_device *dev; struct btrfs_fs_info *fs_info; u64 length; u64 logical; u64 generation; unsigned int failed_mirror_index; unsigned int is_metadata; unsigned int have_csum; u8 *csum; struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */ struct scrub_block *sblock_bad; int ret; int mirror_index; int page_num; int success; static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); BUG_ON(sblock_to_check->page_count < 1); fs_info = sctx->dev_root->fs_info; if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) { /* * if we find an error in a super block, we just report it. * They will get written with the next transaction commit * anyway */ spin_lock(&sctx->stat_lock); ++sctx->stat.super_errors; spin_unlock(&sctx->stat_lock); return 0; } length = sblock_to_check->page_count * PAGE_SIZE; logical = sblock_to_check->pagev[0]->logical; generation = sblock_to_check->pagev[0]->generation; BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1); failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1; is_metadata = !(sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA); have_csum = sblock_to_check->pagev[0]->have_csum; csum = sblock_to_check->pagev[0]->csum; dev = sblock_to_check->pagev[0]->dev; if (sctx->is_dev_replace && !is_metadata && !have_csum) { sblocks_for_recheck = NULL; goto nodatasum_case; } /* * read all mirrors one after the other. This includes to * re-read the extent or metadata block that failed (that was * the cause that this fixup code is called) another time, * page by page this time in order to know which pages * caused I/O errors and which ones are good (for all mirrors). * It is the goal to handle the situation when more than one * mirror contains I/O errors, but the errors do not * overlap, i.e. the data can be repaired by selecting the * pages from those mirrors without I/O error on the * particular pages. One example (with blocks >= 2 * PAGE_SIZE) * would be that mirror #1 has an I/O error on the first page, * the second page is good, and mirror #2 has an I/O error on * the second page, but the first page is good. * Then the first page of the first mirror can be repaired by * taking the first page of the second mirror, and the * second page of the second mirror can be repaired by * copying the contents of the 2nd page of the 1st mirror. * One more note: if the pages of one mirror contain I/O * errors, the checksum cannot be verified. In order to get * the best data for repairing, the first attempt is to find * a mirror without I/O errors and with a validated checksum. * Only if this is not possible, the pages are picked from * mirrors with I/O errors without considering the checksum. * If the latter is the case, at the end, the checksum of the * repaired area is verified in order to correctly maintain * the statistics. */ sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS * sizeof(*sblocks_for_recheck), GFP_NOFS); if (!sblocks_for_recheck) { spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; sctx->stat.read_errors++; sctx->stat.uncorrectable_errors++; spin_unlock(&sctx->stat_lock); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS); goto out; } /* setup the context, map the logical blocks and alloc the pages */ ret = scrub_setup_recheck_block(sctx, fs_info, sblock_to_check, length, logical, sblocks_for_recheck); if (ret) { spin_lock(&sctx->stat_lock); sctx->stat.read_errors++; sctx->stat.uncorrectable_errors++; spin_unlock(&sctx->stat_lock); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS); goto out; } BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS); sblock_bad = sblocks_for_recheck + failed_mirror_index; /* build and submit the bios for the failed mirror, check checksums */ scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum, csum, generation, sctx->csum_size); if (!sblock_bad->header_error && !sblock_bad->checksum_error && sblock_bad->no_io_error_seen) { /* * the error disappeared after reading page by page, or * the area was part of a huge bio and other parts of the * bio caused I/O errors, or the block layer merged several * read requests into one and the error is caused by a * different bio (usually one of the two latter cases is * the cause) */ spin_lock(&sctx->stat_lock); sctx->stat.unverified_errors++; spin_unlock(&sctx->stat_lock); if (sctx->is_dev_replace) scrub_write_block_to_dev_replace(sblock_bad); goto out; } if (!sblock_bad->no_io_error_seen) { spin_lock(&sctx->stat_lock); sctx->stat.read_errors++; spin_unlock(&sctx->stat_lock); if (__ratelimit(&_rs)) scrub_print_warning("i/o error", sblock_to_check); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS); } else if (sblock_bad->checksum_error) { spin_lock(&sctx->stat_lock); sctx->stat.csum_errors++; spin_unlock(&sctx->stat_lock); if (__ratelimit(&_rs)) scrub_print_warning("checksum error", sblock_to_check); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS); } else if (sblock_bad->header_error) { spin_lock(&sctx->stat_lock); sctx->stat.verify_errors++; spin_unlock(&sctx->stat_lock); if (__ratelimit(&_rs)) scrub_print_warning("checksum/header error", sblock_to_check); if (sblock_bad->generation_error) btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_GENERATION_ERRS); else btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS); } if (sctx->readonly && !sctx->is_dev_replace) goto did_not_correct_error; if (!is_metadata && !have_csum) { struct scrub_fixup_nodatasum *fixup_nodatasum; nodatasum_case: WARN_ON(sctx->is_dev_replace); /* * !is_metadata and !have_csum, this means that the data * might not be COW'ed, that it might be modified * concurrently. The general strategy to work on the * commit root does not help in the case when COW is not * used. */ fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS); if (!fixup_nodatasum) goto did_not_correct_error; fixup_nodatasum->sctx = sctx; fixup_nodatasum->dev = dev; fixup_nodatasum->logical = logical; fixup_nodatasum->root = fs_info->extent_root; fixup_nodatasum->mirror_num = failed_mirror_index + 1; scrub_pending_trans_workers_inc(sctx); fixup_nodatasum->work.func = scrub_fixup_nodatasum; btrfs_queue_worker(&fs_info->scrub_workers, &fixup_nodatasum->work); goto out; } /* * now build and submit the bios for the other mirrors, check * checksums. * First try to pick the mirror which is completely without I/O * errors and also does not have a checksum error. * If one is found, and if a checksum is present, the full block * that is known to contain an error is rewritten. Afterwards * the block is known to be corrected. * If a mirror is found which is completely correct, and no * checksum is present, only those pages are rewritten that had * an I/O error in the block to be repaired, since it cannot be * determined, which copy of the other pages is better (and it * could happen otherwise that a correct page would be * overwritten by a bad one). */ for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS && sblocks_for_recheck[mirror_index].page_count > 0; mirror_index++) { struct scrub_block *sblock_other; if (mirror_index == failed_mirror_index) continue; sblock_other = sblocks_for_recheck + mirror_index; /* build and submit the bios, check checksums */ scrub_recheck_block(fs_info, sblock_other, is_metadata, have_csum, csum, generation, sctx->csum_size); if (!sblock_other->header_error && !sblock_other->checksum_error && sblock_other->no_io_error_seen) { if (sctx->is_dev_replace) { scrub_write_block_to_dev_replace(sblock_other); } else { int force_write = is_metadata || have_csum; ret = scrub_repair_block_from_good_copy( sblock_bad, sblock_other, force_write); } if (0 == ret) goto corrected_error; } } /* * for dev_replace, pick good pages and write to the target device. */ if (sctx->is_dev_replace) { success = 1; for (page_num = 0; page_num < sblock_bad->page_count; page_num++) { int sub_success; sub_success = 0; for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS && sblocks_for_recheck[mirror_index].page_count > 0; mirror_index++) { struct scrub_block *sblock_other = sblocks_for_recheck + mirror_index; struct scrub_page *page_other = sblock_other->pagev[page_num]; if (!page_other->io_error) { ret = scrub_write_page_to_dev_replace( sblock_other, page_num); if (ret == 0) { /* succeeded for this page */ sub_success = 1; break; } else { btrfs_dev_replace_stats_inc( &sctx->dev_root-> fs_info->dev_replace. num_write_errors); } } } if (!sub_success) { /* * did not find a mirror to fetch the page * from. scrub_write_page_to_dev_replace() * handles this case (page->io_error), by * filling the block with zeros before * submitting the write request */ success = 0; ret = scrub_write_page_to_dev_replace( sblock_bad, page_num); if (ret) btrfs_dev_replace_stats_inc( &sctx->dev_root->fs_info-> dev_replace.num_write_errors); } } goto out; } /* * for regular scrub, repair those pages that are errored. * In case of I/O errors in the area that is supposed to be * repaired, continue by picking good copies of those pages. * Select the good pages from mirrors to rewrite bad pages from * the area to fix. Afterwards verify the checksum of the block * that is supposed to be repaired. This verification step is * only done for the purpose of statistic counting and for the * final scrub report, whether errors remain. * A perfect algorithm could make use of the checksum and try * all possible combinations of pages from the different mirrors * until the checksum verification succeeds. For example, when * the 2nd page of mirror #1 faces I/O errors, and the 2nd page * of mirror #2 is readable but the final checksum test fails, * then the 2nd page of mirror #3 could be tried, whether now * the final checksum succeedes. But this would be a rare * exception and is therefore not implemented. At least it is * avoided that the good copy is overwritten. * A more useful improvement would be to pick the sectors * without I/O error based on sector sizes (512 bytes on legacy * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one * mirror could be repaired by taking 512 byte of a different * mirror, even if other 512 byte sectors in the same PAGE_SIZE * area are unreadable. */ /* can only fix I/O errors from here on */ if (sblock_bad->no_io_error_seen) goto did_not_correct_error; success = 1; for (page_num = 0; page_num < sblock_bad->page_count; page_num++) { struct scrub_page *page_bad = sblock_bad->pagev[page_num]; if (!page_bad->io_error) continue; for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS && sblocks_for_recheck[mirror_index].page_count > 0; mirror_index++) { struct scrub_block *sblock_other = sblocks_for_recheck + mirror_index; struct scrub_page *page_other = sblock_other->pagev[ page_num]; if (!page_other->io_error) { ret = scrub_repair_page_from_good_copy( sblock_bad, sblock_other, page_num, 0); if (0 == ret) { page_bad->io_error = 0; break; /* succeeded for this page */ } } } if (page_bad->io_error) { /* did not find a mirror to copy the page from */ success = 0; } } if (success) { if (is_metadata || have_csum) { /* * need to verify the checksum now that all * sectors on disk are repaired (the write * request for data to be repaired is on its way). * Just be lazy and use scrub_recheck_block() * which re-reads the data before the checksum * is verified, but most likely the data comes out * of the page cache. */ scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum, csum, generation, sctx->csum_size); if (!sblock_bad->header_error && !sblock_bad->checksum_error && sblock_bad->no_io_error_seen) goto corrected_error; else goto did_not_correct_error; } else { corrected_error: spin_lock(&sctx->stat_lock); sctx->stat.corrected_errors++; spin_unlock(&sctx->stat_lock); printk_ratelimited_in_rcu(KERN_ERR "btrfs: fixed up error at logical %llu on dev %s\n", logical, rcu_str_deref(dev->name)); } } else { did_not_correct_error: spin_lock(&sctx->stat_lock); sctx->stat.uncorrectable_errors++; spin_unlock(&sctx->stat_lock); printk_ratelimited_in_rcu(KERN_ERR "btrfs: unable to fixup (regular) error at logical %llu on dev %s\n", logical, rcu_str_deref(dev->name)); } out: if (sblocks_for_recheck) { for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS; mirror_index++) { struct scrub_block *sblock = sblocks_for_recheck + mirror_index; int page_index; for (page_index = 0; page_index < sblock->page_count; page_index++) { sblock->pagev[page_index]->sblock = NULL; scrub_page_put(sblock->pagev[page_index]); } } kfree(sblocks_for_recheck); } return 0; } static int scrub_setup_recheck_block(struct scrub_ctx *sctx, struct btrfs_fs_info *fs_info, struct scrub_block *original_sblock, u64 length, u64 logical, struct scrub_block *sblocks_for_recheck) { int page_index; int mirror_index; int ret; /* * note: the two members ref_count and outstanding_pages * are not used (and not set) in the blocks that are used for * the recheck procedure */ page_index = 0; while (length > 0) { u64 sublen = min_t(u64, length, PAGE_SIZE); u64 mapped_length = sublen; struct btrfs_bio *bbio = NULL; /* * with a length of PAGE_SIZE, each returned stripe * represents one mirror */ ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical, &mapped_length, &bbio, 0); if (ret || !bbio || mapped_length < sublen) { kfree(bbio); return -EIO; } BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO); for (mirror_index = 0; mirror_index < (int)bbio->num_stripes; mirror_index++) { struct scrub_block *sblock; struct scrub_page *page; if (mirror_index >= BTRFS_MAX_MIRRORS) continue; sblock = sblocks_for_recheck + mirror_index; sblock->sctx = sctx; page = kzalloc(sizeof(*page), GFP_NOFS); if (!page) { leave_nomem: spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); kfree(bbio); return -ENOMEM; } scrub_page_get(page); sblock->pagev[page_index] = page; page->logical = logical; page->physical = bbio->stripes[mirror_index].physical; BUG_ON(page_index >= original_sblock->page_count); page->physical_for_dev_replace = original_sblock->pagev[page_index]-> physical_for_dev_replace; /* for missing devices, dev->bdev is NULL */ page->dev = bbio->stripes[mirror_index].dev; page->mirror_num = mirror_index + 1; sblock->page_count++; page->page = alloc_page(GFP_NOFS); if (!page->page) goto leave_nomem; } kfree(bbio); length -= sublen; logical += sublen; page_index++; } return 0; } /* * this function will check the on disk data for checksum errors, header * errors and read I/O errors. If any I/O errors happen, the exact pages * which are errored are marked as being bad. The goal is to enable scrub * to take those pages that are not errored from all the mirrors so that * the pages that are errored in the just handled mirror can be repaired. */ static void scrub_recheck_block(struct btrfs_fs_info *fs_info, struct scrub_block *sblock, int is_metadata, int have_csum, u8 *csum, u64 generation, u16 csum_size) { int page_num; sblock->no_io_error_seen = 1; sblock->header_error = 0; sblock->checksum_error = 0; for (page_num = 0; page_num < sblock->page_count; page_num++) { struct bio *bio; struct scrub_page *page = sblock->pagev[page_num]; DECLARE_COMPLETION_ONSTACK(complete); if (page->dev->bdev == NULL) { page->io_error = 1; sblock->no_io_error_seen = 0; continue; } WARN_ON(!page->page); bio = btrfs_io_bio_alloc(GFP_NOFS, 1); if (!bio) { page->io_error = 1; sblock->no_io_error_seen = 0; continue; } bio->bi_bdev = page->dev->bdev; bio->bi_sector = page->physical >> 9; bio->bi_end_io = scrub_complete_bio_end_io; bio->bi_private = &complete; bio_add_page(bio, page->page, PAGE_SIZE, 0); btrfsic_submit_bio(READ, bio); /* this will also unplug the queue */ wait_for_completion(&complete); page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags); if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) sblock->no_io_error_seen = 0; bio_put(bio); } if (sblock->no_io_error_seen) scrub_recheck_block_checksum(fs_info, sblock, is_metadata, have_csum, csum, generation, csum_size); return; } static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info, struct scrub_block *sblock, int is_metadata, int have_csum, const u8 *csum, u64 generation, u16 csum_size) { int page_num; u8 calculated_csum[BTRFS_CSUM_SIZE]; u32 crc = ~(u32)0; void *mapped_buffer; WARN_ON(!sblock->pagev[0]->page); if (is_metadata) { struct btrfs_header *h; mapped_buffer = kmap_atomic(sblock->pagev[0]->page); h = (struct btrfs_header *)mapped_buffer; if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h) || memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) || memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid, BTRFS_UUID_SIZE)) { sblock->header_error = 1; } else if (generation != btrfs_stack_header_generation(h)) { sblock->header_error = 1; sblock->generation_error = 1; } csum = h->csum; } else { if (!have_csum) return; mapped_buffer = kmap_atomic(sblock->pagev[0]->page); } for (page_num = 0;;) { if (page_num == 0 && is_metadata) crc = btrfs_csum_data( ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE, crc, PAGE_SIZE - BTRFS_CSUM_SIZE); else crc = btrfs_csum_data(mapped_buffer, crc, PAGE_SIZE); kunmap_atomic(mapped_buffer); page_num++; if (page_num >= sblock->page_count) break; WARN_ON(!sblock->pagev[page_num]->page); mapped_buffer = kmap_atomic(sblock->pagev[page_num]->page); } btrfs_csum_final(crc, calculated_csum); if (memcmp(calculated_csum, csum, csum_size)) sblock->checksum_error = 1; } static void scrub_complete_bio_end_io(struct bio *bio, int err) { complete((struct completion *)bio->bi_private); } static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad, struct scrub_block *sblock_good, int force_write) { int page_num; int ret = 0; for (page_num = 0; page_num < sblock_bad->page_count; page_num++) { int ret_sub; ret_sub = scrub_repair_page_from_good_copy(sblock_bad, sblock_good, page_num, force_write); if (ret_sub) ret = ret_sub; } return ret; } static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad, struct scrub_block *sblock_good, int page_num, int force_write) { struct scrub_page *page_bad = sblock_bad->pagev[page_num]; struct scrub_page *page_good = sblock_good->pagev[page_num]; BUG_ON(page_bad->page == NULL); BUG_ON(page_good->page == NULL); if (force_write || sblock_bad->header_error || sblock_bad->checksum_error || page_bad->io_error) { struct bio *bio; int ret; DECLARE_COMPLETION_ONSTACK(complete); if (!page_bad->dev->bdev) { printk_ratelimited(KERN_WARNING "btrfs: scrub_repair_page_from_good_copy(bdev == NULL) is unexpected!\n"); return -EIO; } bio = btrfs_io_bio_alloc(GFP_NOFS, 1); if (!bio) return -EIO; bio->bi_bdev = page_bad->dev->bdev; bio->bi_sector = page_bad->physical >> 9; bio->bi_end_io = scrub_complete_bio_end_io; bio->bi_private = &complete; ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0); if (PAGE_SIZE != ret) { bio_put(bio); return -EIO; } btrfsic_submit_bio(WRITE, bio); /* this will also unplug the queue */ wait_for_completion(&complete); if (!bio_flagged(bio, BIO_UPTODATE)) { btrfs_dev_stat_inc_and_print(page_bad->dev, BTRFS_DEV_STAT_WRITE_ERRS); btrfs_dev_replace_stats_inc( &sblock_bad->sctx->dev_root->fs_info-> dev_replace.num_write_errors); bio_put(bio); return -EIO; } bio_put(bio); } return 0; } static void scrub_write_block_to_dev_replace(struct scrub_block *sblock) { int page_num; for (page_num = 0; page_num < sblock->page_count; page_num++) { int ret; ret = scrub_write_page_to_dev_replace(sblock, page_num); if (ret) btrfs_dev_replace_stats_inc( &sblock->sctx->dev_root->fs_info->dev_replace. num_write_errors); } } static int scrub_write_page_to_dev_replace(struct scrub_block *sblock, int page_num) { struct scrub_page *spage = sblock->pagev[page_num]; BUG_ON(spage->page == NULL); if (spage->io_error) { void *mapped_buffer = kmap_atomic(spage->page); memset(mapped_buffer, 0, PAGE_CACHE_SIZE); flush_dcache_page(spage->page); kunmap_atomic(mapped_buffer); } return scrub_add_page_to_wr_bio(sblock->sctx, spage); } static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx, struct scrub_page *spage) { struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx; struct scrub_bio *sbio; int ret; mutex_lock(&wr_ctx->wr_lock); again: if (!wr_ctx->wr_curr_bio) { wr_ctx->wr_curr_bio = kzalloc(sizeof(*wr_ctx->wr_curr_bio), GFP_NOFS); if (!wr_ctx->wr_curr_bio) { mutex_unlock(&wr_ctx->wr_lock); return -ENOMEM; } wr_ctx->wr_curr_bio->sctx = sctx; wr_ctx->wr_curr_bio->page_count = 0; } sbio = wr_ctx->wr_curr_bio; if (sbio->page_count == 0) { struct bio *bio; sbio->physical = spage->physical_for_dev_replace; sbio->logical = spage->logical; sbio->dev = wr_ctx->tgtdev; bio = sbio->bio; if (!bio) { bio = btrfs_io_bio_alloc(GFP_NOFS, wr_ctx->pages_per_wr_bio); if (!bio) { mutex_unlock(&wr_ctx->wr_lock); return -ENOMEM; } sbio->bio = bio; } bio->bi_private = sbio; bio->bi_end_io = scrub_wr_bio_end_io; bio->bi_bdev = sbio->dev->bdev; bio->bi_sector = sbio->physical >> 9; sbio->err = 0; } else if (sbio->physical + sbio->page_count * PAGE_SIZE != spage->physical_for_dev_replace || sbio->logical + sbio->page_count * PAGE_SIZE != spage->logical) { scrub_wr_submit(sctx); goto again; } ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0); if (ret != PAGE_SIZE) { if (sbio->page_count < 1) { bio_put(sbio->bio); sbio->bio = NULL; mutex_unlock(&wr_ctx->wr_lock); return -EIO; } scrub_wr_submit(sctx); goto again; } sbio->pagev[sbio->page_count] = spage; scrub_page_get(spage); sbio->page_count++; if (sbio->page_count == wr_ctx->pages_per_wr_bio) scrub_wr_submit(sctx); mutex_unlock(&wr_ctx->wr_lock); return 0; } static void scrub_wr_submit(struct scrub_ctx *sctx) { struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx; struct scrub_bio *sbio; if (!wr_ctx->wr_curr_bio) return; sbio = wr_ctx->wr_curr_bio; wr_ctx->wr_curr_bio = NULL; WARN_ON(!sbio->bio->bi_bdev); scrub_pending_bio_inc(sctx); /* process all writes in a single worker thread. Then the block layer * orders the requests before sending them to the driver which * doubled the write performance on spinning disks when measured * with Linux 3.5 */ btrfsic_submit_bio(WRITE, sbio->bio); } static void scrub_wr_bio_end_io(struct bio *bio, int err) { struct scrub_bio *sbio = bio->bi_private; struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info; sbio->err = err; sbio->bio = bio; sbio->work.func = scrub_wr_bio_end_io_worker; btrfs_queue_worker(&fs_info->scrub_wr_completion_workers, &sbio->work); } static void scrub_wr_bio_end_io_worker(struct btrfs_work *work) { struct scrub_bio *sbio = container_of(work, struct scrub_bio, work); struct scrub_ctx *sctx = sbio->sctx; int i; WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO); if (sbio->err) { struct btrfs_dev_replace *dev_replace = &sbio->sctx->dev_root->fs_info->dev_replace; for (i = 0; i < sbio->page_count; i++) { struct scrub_page *spage = sbio->pagev[i]; spage->io_error = 1; btrfs_dev_replace_stats_inc(&dev_replace-> num_write_errors); } } for (i = 0; i < sbio->page_count; i++) scrub_page_put(sbio->pagev[i]); bio_put(sbio->bio); kfree(sbio); scrub_pending_bio_dec(sctx); } static int scrub_checksum(struct scrub_block *sblock) { u64 flags; int ret; WARN_ON(sblock->page_count < 1); flags = sblock->pagev[0]->flags; ret = 0; if (flags & BTRFS_EXTENT_FLAG_DATA) ret = scrub_checksum_data(sblock); else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) ret = scrub_checksum_tree_block(sblock); else if (flags & BTRFS_EXTENT_FLAG_SUPER) (void)scrub_checksum_super(sblock); else WARN_ON(1); if (ret) scrub_handle_errored_block(sblock); return ret; } static int scrub_checksum_data(struct scrub_block *sblock) { struct scrub_ctx *sctx = sblock->sctx; u8 csum[BTRFS_CSUM_SIZE]; u8 *on_disk_csum; struct page *page; void *buffer; u32 crc = ~(u32)0; int fail = 0; u64 len; int index; BUG_ON(sblock->page_count < 1); if (!sblock->pagev[0]->have_csum) return 0; on_disk_csum = sblock->pagev[0]->csum; page = sblock->pagev[0]->page; buffer = kmap_atomic(page); len = sctx->sectorsize; index = 0; for (;;) { u64 l = min_t(u64, len, PAGE_SIZE); crc = btrfs_csum_data(buffer, crc, l); kunmap_atomic(buffer); len -= l; if (len == 0) break; index++; BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; buffer = kmap_atomic(page); } btrfs_csum_final(crc, csum); if (memcmp(csum, on_disk_csum, sctx->csum_size)) fail = 1; return fail; } static int scrub_checksum_tree_block(struct scrub_block *sblock) { struct scrub_ctx *sctx = sblock->sctx; struct btrfs_header *h; struct btrfs_root *root = sctx->dev_root; struct btrfs_fs_info *fs_info = root->fs_info; u8 calculated_csum[BTRFS_CSUM_SIZE]; u8 on_disk_csum[BTRFS_CSUM_SIZE]; struct page *page; void *mapped_buffer; u64 mapped_size; void *p; u32 crc = ~(u32)0; int fail = 0; int crc_fail = 0; u64 len; int index; BUG_ON(sblock->page_count < 1); page = sblock->pagev[0]->page; mapped_buffer = kmap_atomic(page); h = (struct btrfs_header *)mapped_buffer; memcpy(on_disk_csum, h->csum, sctx->csum_size); /* * we don't use the getter functions here, as we * a) don't have an extent buffer and * b) the page is already kmapped */ if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h)) ++fail; if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) ++fail; if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE)) ++fail; if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid, BTRFS_UUID_SIZE)) ++fail; WARN_ON(sctx->nodesize != sctx->leafsize); len = sctx->nodesize - BTRFS_CSUM_SIZE; mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE; p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE; index = 0; for (;;) { u64 l = min_t(u64, len, mapped_size); crc = btrfs_csum_data(p, crc, l); kunmap_atomic(mapped_buffer); len -= l; if (len == 0) break; index++; BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; mapped_buffer = kmap_atomic(page); mapped_size = PAGE_SIZE; p = mapped_buffer; } btrfs_csum_final(crc, calculated_csum); if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size)) ++crc_fail; return fail || crc_fail; } static int scrub_checksum_super(struct scrub_block *sblock) { struct btrfs_super_block *s; struct scrub_ctx *sctx = sblock->sctx; struct btrfs_root *root = sctx->dev_root; struct btrfs_fs_info *fs_info = root->fs_info; u8 calculated_csum[BTRFS_CSUM_SIZE]; u8 on_disk_csum[BTRFS_CSUM_SIZE]; struct page *page; void *mapped_buffer; u64 mapped_size; void *p; u32 crc = ~(u32)0; int fail_gen = 0; int fail_cor = 0; u64 len; int index; BUG_ON(sblock->page_count < 1); page = sblock->pagev[0]->page; mapped_buffer = kmap_atomic(page); s = (struct btrfs_super_block *)mapped_buffer; memcpy(on_disk_csum, s->csum, sctx->csum_size); if (sblock->pagev[0]->logical != btrfs_super_bytenr(s)) ++fail_cor; if (sblock->pagev[0]->generation != btrfs_super_generation(s)) ++fail_gen; if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE)) ++fail_cor; len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE; mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE; p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE; index = 0; for (;;) { u64 l = min_t(u64, len, mapped_size); crc = btrfs_csum_data(p, crc, l); kunmap_atomic(mapped_buffer); len -= l; if (len == 0) break; index++; BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; mapped_buffer = kmap_atomic(page); mapped_size = PAGE_SIZE; p = mapped_buffer; } btrfs_csum_final(crc, calculated_csum); if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size)) ++fail_cor; if (fail_cor + fail_gen) { /* * if we find an error in a super block, we just report it. * They will get written with the next transaction commit * anyway */ spin_lock(&sctx->stat_lock); ++sctx->stat.super_errors; spin_unlock(&sctx->stat_lock); if (fail_cor) btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev, BTRFS_DEV_STAT_CORRUPTION_ERRS); else btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev, BTRFS_DEV_STAT_GENERATION_ERRS); } return fail_cor + fail_gen; } static void scrub_block_get(struct scrub_block *sblock) { atomic_inc(&sblock->ref_count); } static void scrub_block_put(struct scrub_block *sblock) { if (atomic_dec_and_test(&sblock->ref_count)) { int i; for (i = 0; i < sblock->page_count; i++) scrub_page_put(sblock->pagev[i]); kfree(sblock); } } static void scrub_page_get(struct scrub_page *spage) { atomic_inc(&spage->ref_count); } static void scrub_page_put(struct scrub_page *spage) { if (atomic_dec_and_test(&spage->ref_count)) { if (spage->page) __free_page(spage->page); kfree(spage); } } static void scrub_submit(struct scrub_ctx *sctx) { struct scrub_bio *sbio; if (sctx->curr == -1) return; sbio = sctx->bios[sctx->curr]; sctx->curr = -1; scrub_pending_bio_inc(sctx); if (!sbio->bio->bi_bdev) { /* * this case should not happen. If btrfs_map_block() is * wrong, it could happen for dev-replace operations on * missing devices when no mirrors are available, but in * this case it should already fail the mount. * This case is handled correctly (but _very_ slowly). */ printk_ratelimited(KERN_WARNING "btrfs: scrub_submit(bio bdev == NULL) is unexpected!\n"); bio_endio(sbio->bio, -EIO); } else { btrfsic_submit_bio(READ, sbio->bio); } } static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx, struct scrub_page *spage) { struct scrub_block *sblock = spage->sblock; struct scrub_bio *sbio; int ret; again: /* * grab a fresh bio or wait for one to become available */ while (sctx->curr == -1) { spin_lock(&sctx->list_lock); sctx->curr = sctx->first_free; if (sctx->curr != -1) { sctx->first_free = sctx->bios[sctx->curr]->next_free; sctx->bios[sctx->curr]->next_free = -1; sctx->bios[sctx->curr]->page_count = 0; spin_unlock(&sctx->list_lock); } else { spin_unlock(&sctx->list_lock); wait_event(sctx->list_wait, sctx->first_free != -1); } } sbio = sctx->bios[sctx->curr]; if (sbio->page_count == 0) { struct bio *bio; sbio->physical = spage->physical; sbio->logical = spage->logical; sbio->dev = spage->dev; bio = sbio->bio; if (!bio) { bio = btrfs_io_bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio); if (!bio) return -ENOMEM; sbio->bio = bio; } bio->bi_private = sbio; bio->bi_end_io = scrub_bio_end_io; bio->bi_bdev = sbio->dev->bdev; bio->bi_sector = sbio->physical >> 9; sbio->err = 0; } else if (sbio->physical + sbio->page_count * PAGE_SIZE != spage->physical || sbio->logical + sbio->page_count * PAGE_SIZE != spage->logical || sbio->dev != spage->dev) { scrub_submit(sctx); goto again; } sbio->pagev[sbio->page_count] = spage; ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0); if (ret != PAGE_SIZE) { if (sbio->page_count < 1) { bio_put(sbio->bio); sbio->bio = NULL; return -EIO; } scrub_submit(sctx); goto again; } scrub_block_get(sblock); /* one for the page added to the bio */ atomic_inc(&sblock->outstanding_pages); sbio->page_count++; if (sbio->page_count == sctx->pages_per_rd_bio) scrub_submit(sctx); return 0; } static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len, u64 physical, struct btrfs_device *dev, u64 flags, u64 gen, int mirror_num, u8 *csum, int force, u64 physical_for_dev_replace) { struct scrub_block *sblock; int index; sblock = kzalloc(sizeof(*sblock), GFP_NOFS); if (!sblock) { spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); return -ENOMEM; } /* one ref inside this function, plus one for each page added to * a bio later on */ atomic_set(&sblock->ref_count, 1); sblock->sctx = sctx; sblock->no_io_error_seen = 1; for (index = 0; len > 0; index++) { struct scrub_page *spage; u64 l = min_t(u64, len, PAGE_SIZE); spage = kzalloc(sizeof(*spage), GFP_NOFS); if (!spage) { leave_nomem: spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); scrub_block_put(sblock); return -ENOMEM; } BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK); scrub_page_get(spage); sblock->pagev[index] = spage; spage->sblock = sblock; spage->dev = dev; spage->flags = flags; spage->generation = gen; spage->logical = logical; spage->physical = physical; spage->physical_for_dev_replace = physical_for_dev_replace; spage->mirror_num = mirror_num; if (csum) { spage->have_csum = 1; memcpy(spage->csum, csum, sctx->csum_size); } else { spage->have_csum = 0; } sblock->page_count++; spage->page = alloc_page(GFP_NOFS); if (!spage->page) goto leave_nomem; len -= l; logical += l; physical += l; physical_for_dev_replace += l; } WARN_ON(sblock->page_count == 0); for (index = 0; index < sblock->page_count; index++) { struct scrub_page *spage = sblock->pagev[index]; int ret; ret = scrub_add_page_to_rd_bio(sctx, spage); if (ret) { scrub_block_put(sblock); return ret; } } if (force) scrub_submit(sctx); /* last one frees, either here or in bio completion for last page */ scrub_block_put(sblock); return 0; } static void scrub_bio_end_io(struct bio *bio, int err) { struct scrub_bio *sbio = bio->bi_private; struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info; sbio->err = err; sbio->bio = bio; btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work); } static void scrub_bio_end_io_worker(struct btrfs_work *work) { struct scrub_bio *sbio = container_of(work, struct scrub_bio, work); struct scrub_ctx *sctx = sbio->sctx; int i; BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO); if (sbio->err) { for (i = 0; i < sbio->page_count; i++) { struct scrub_page *spage = sbio->pagev[i]; spage->io_error = 1; spage->sblock->no_io_error_seen = 0; } } /* now complete the scrub_block items that have all pages completed */ for (i = 0; i < sbio->page_count; i++) { struct scrub_page *spage = sbio->pagev[i]; struct scrub_block *sblock = spage->sblock; if (atomic_dec_and_test(&sblock->outstanding_pages)) scrub_block_complete(sblock); scrub_block_put(sblock); } bio_put(sbio->bio); sbio->bio = NULL; spin_lock(&sctx->list_lock); sbio->next_free = sctx->first_free; sctx->first_free = sbio->index; spin_unlock(&sctx->list_lock); if (sctx->is_dev_replace && atomic_read(&sctx->wr_ctx.flush_all_writes)) { mutex_lock(&sctx->wr_ctx.wr_lock); scrub_wr_submit(sctx); mutex_unlock(&sctx->wr_ctx.wr_lock); } scrub_pending_bio_dec(sctx); } static void scrub_block_complete(struct scrub_block *sblock) { if (!sblock->no_io_error_seen) { scrub_handle_errored_block(sblock); } else { /* * if has checksum error, write via repair mechanism in * dev replace case, otherwise write here in dev replace * case. */ if (!scrub_checksum(sblock) && sblock->sctx->is_dev_replace) scrub_write_block_to_dev_replace(sblock); } } static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len, u8 *csum) { struct btrfs_ordered_sum *sum = NULL; unsigned long index; unsigned long num_sectors; while (!list_empty(&sctx->csum_list)) { sum = list_first_entry(&sctx->csum_list, struct btrfs_ordered_sum, list); if (sum->bytenr > logical) return 0; if (sum->bytenr + sum->len > logical) break; ++sctx->stat.csum_discards; list_del(&sum->list); kfree(sum); sum = NULL; } if (!sum) return 0; index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize; num_sectors = sum->len / sctx->sectorsize; memcpy(csum, sum->sums + index, sctx->csum_size); if (index == num_sectors - 1) { list_del(&sum->list); kfree(sum); } return 1; } /* scrub extent tries to collect up to 64 kB for each bio */ static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len, u64 physical, struct btrfs_device *dev, u64 flags, u64 gen, int mirror_num, u64 physical_for_dev_replace) { int ret; u8 csum[BTRFS_CSUM_SIZE]; u32 blocksize; if (flags & BTRFS_EXTENT_FLAG_DATA) { blocksize = sctx->sectorsize; spin_lock(&sctx->stat_lock); sctx->stat.data_extents_scrubbed++; sctx->stat.data_bytes_scrubbed += len; spin_unlock(&sctx->stat_lock); } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { WARN_ON(sctx->nodesize != sctx->leafsize); blocksize = sctx->nodesize; spin_lock(&sctx->stat_lock); sctx->stat.tree_extents_scrubbed++; sctx->stat.tree_bytes_scrubbed += len; spin_unlock(&sctx->stat_lock); } else { blocksize = sctx->sectorsize; WARN_ON(1); } while (len) { u64 l = min_t(u64, len, blocksize); int have_csum = 0; if (flags & BTRFS_EXTENT_FLAG_DATA) { /* push csums to sbio */ have_csum = scrub_find_csum(sctx, logical, l, csum); if (have_csum == 0) ++sctx->stat.no_csum; if (sctx->is_dev_replace && !have_csum) { ret = copy_nocow_pages(sctx, logical, l, mirror_num, physical_for_dev_replace); goto behind_scrub_pages; } } ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen, mirror_num, have_csum ? csum : NULL, 0, physical_for_dev_replace); behind_scrub_pages: if (ret) return ret; len -= l; logical += l; physical += l; physical_for_dev_replace += l; } return 0; } static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, struct map_lookup *map, struct btrfs_device *scrub_dev, int num, u64 base, u64 length, int is_dev_replace) { struct btrfs_path *path; struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info; struct btrfs_root *root = fs_info->extent_root; struct btrfs_root *csum_root = fs_info->csum_root; struct btrfs_extent_item *extent; struct blk_plug plug; u64 flags; int ret; int slot; u64 nstripes; struct extent_buffer *l; struct btrfs_key key; u64 physical; u64 logical; u64 logic_end; u64 generation; int mirror_num; struct reada_control *reada1; struct reada_control *reada2; struct btrfs_key key_start; struct btrfs_key key_end; u64 increment = map->stripe_len; u64 offset; u64 extent_logical; u64 extent_physical; u64 extent_len; struct btrfs_device *extent_dev; int extent_mirror_num; int stop_loop; if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) { if (num >= nr_data_stripes(map)) { return 0; } } nstripes = length; offset = 0; do_div(nstripes, map->stripe_len); if (map->type & BTRFS_BLOCK_GROUP_RAID0) { offset = map->stripe_len * num; increment = map->stripe_len * map->num_stripes; mirror_num = 1; } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { int factor = map->num_stripes / map->sub_stripes; offset = map->stripe_len * (num / map->sub_stripes); increment = map->stripe_len * factor; mirror_num = num % map->sub_stripes + 1; } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) { increment = map->stripe_len; mirror_num = num % map->num_stripes + 1; } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { increment = map->stripe_len; mirror_num = num % map->num_stripes + 1; } else { increment = map->stripe_len; mirror_num = 1; } path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* * work on commit root. The related disk blocks are static as * long as COW is applied. This means, it is save to rewrite * them to repair disk errors without any race conditions */ path->search_commit_root = 1; path->skip_locking = 1; /* * trigger the readahead for extent tree csum tree and wait for * completion. During readahead, the scrub is officially paused * to not hold off transaction commits */ logical = base + offset; wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0); atomic_inc(&fs_info->scrubs_paused); wake_up(&fs_info->scrub_pause_wait); /* FIXME it might be better to start readahead at commit root */ key_start.objectid = logical; key_start.type = BTRFS_EXTENT_ITEM_KEY; key_start.offset = (u64)0; key_end.objectid = base + offset + nstripes * increment; key_end.type = BTRFS_METADATA_ITEM_KEY; key_end.offset = (u64)-1; reada1 = btrfs_reada_add(root, &key_start, &key_end); key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID; key_start.type = BTRFS_EXTENT_CSUM_KEY; key_start.offset = logical; key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID; key_end.type = BTRFS_EXTENT_CSUM_KEY; key_end.offset = base + offset + nstripes * increment; reada2 = btrfs_reada_add(csum_root, &key_start, &key_end); if (!IS_ERR(reada1)) btrfs_reada_wait(reada1); if (!IS_ERR(reada2)) btrfs_reada_wait(reada2); mutex_lock(&fs_info->scrub_lock); while (atomic_read(&fs_info->scrub_pause_req)) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, atomic_read(&fs_info->scrub_pause_req) == 0); mutex_lock(&fs_info->scrub_lock); } atomic_dec(&fs_info->scrubs_paused); mutex_unlock(&fs_info->scrub_lock); wake_up(&fs_info->scrub_pause_wait); /* * collect all data csums for the stripe to avoid seeking during * the scrub. This might currently (crc32) end up to be about 1MB */ blk_start_plug(&plug); /* * now find all extents for each stripe and scrub them */ logical = base + offset; physical = map->stripes[num].physical; logic_end = logical + increment * nstripes; ret = 0; while (logical < logic_end) { /* * canceled? */ if (atomic_read(&fs_info->scrub_cancel_req) || atomic_read(&sctx->cancel_req)) { ret = -ECANCELED; goto out; } /* * check to see if we have to pause */ if (atomic_read(&fs_info->scrub_pause_req)) { /* push queued extents */ atomic_set(&sctx->wr_ctx.flush_all_writes, 1); scrub_submit(sctx); mutex_lock(&sctx->wr_ctx.wr_lock); scrub_wr_submit(sctx); mutex_unlock(&sctx->wr_ctx.wr_lock); wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0); atomic_set(&sctx->wr_ctx.flush_all_writes, 0); atomic_inc(&fs_info->scrubs_paused); wake_up(&fs_info->scrub_pause_wait); mutex_lock(&fs_info->scrub_lock); while (atomic_read(&fs_info->scrub_pause_req)) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, atomic_read(&fs_info->scrub_pause_req) == 0); mutex_lock(&fs_info->scrub_lock); } atomic_dec(&fs_info->scrubs_paused); mutex_unlock(&fs_info->scrub_lock); wake_up(&fs_info->scrub_pause_wait); } key.objectid = logical; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = (u64)-1; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0) { ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY); if (ret < 0) goto out; if (ret > 0) { /* there's no smaller item, so stick with the * larger one */ btrfs_release_path(path); ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; } } stop_loop = 0; while (1) { u64 bytes; l = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(l)) { ret = btrfs_next_leaf(root, path); if (ret == 0) continue; if (ret < 0) goto out; stop_loop = 1; break; } btrfs_item_key_to_cpu(l, &key, slot); if (key.type == BTRFS_METADATA_ITEM_KEY) bytes = root->leafsize; else bytes = key.offset; if (key.objectid + bytes <= logical) goto next; if (key.type != BTRFS_EXTENT_ITEM_KEY && key.type != BTRFS_METADATA_ITEM_KEY) goto next; if (key.objectid >= logical + map->stripe_len) { /* out of this device extent */ if (key.objectid >= logic_end) stop_loop = 1; break; } extent = btrfs_item_ptr(l, slot, struct btrfs_extent_item); flags = btrfs_extent_flags(l, extent); generation = btrfs_extent_generation(l, extent); if (key.objectid < logical && (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) { printk(KERN_ERR "btrfs scrub: tree block %llu spanning " "stripes, ignored. logical=%llu\n", key.objectid, logical); goto next; } again: extent_logical = key.objectid; extent_len = bytes; /* * trim extent to this stripe */ if (extent_logical < logical) { extent_len -= logical - extent_logical; extent_logical = logical; } if (extent_logical + extent_len > logical + map->stripe_len) { extent_len = logical + map->stripe_len - extent_logical; } extent_physical = extent_logical - logical + physical; extent_dev = scrub_dev; extent_mirror_num = mirror_num; if (is_dev_replace) scrub_remap_extent(fs_info, extent_logical, extent_len, &extent_physical, &extent_dev, &extent_mirror_num); ret = btrfs_lookup_csums_range(csum_root, logical, logical + map->stripe_len - 1, &sctx->csum_list, 1); if (ret) goto out; ret = scrub_extent(sctx, extent_logical, extent_len, extent_physical, extent_dev, flags, generation, extent_mirror_num, extent_logical - logical + physical); if (ret) goto out; scrub_free_csums(sctx); if (extent_logical + extent_len < key.objectid + bytes) { logical += increment; physical += map->stripe_len; if (logical < key.objectid + bytes) { cond_resched(); goto again; } if (logical >= logic_end) { stop_loop = 1; break; } } next: path->slots[0]++; } btrfs_release_path(path); logical += increment; physical += map->stripe_len; spin_lock(&sctx->stat_lock); if (stop_loop) sctx->stat.last_physical = map->stripes[num].physical + length; else sctx->stat.last_physical = physical; spin_unlock(&sctx->stat_lock); if (stop_loop) break; } out: /* push queued extents */ scrub_submit(sctx); mutex_lock(&sctx->wr_ctx.wr_lock); scrub_wr_submit(sctx); mutex_unlock(&sctx->wr_ctx.wr_lock); blk_finish_plug(&plug); btrfs_free_path(path); return ret < 0 ? ret : 0; } static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx, struct btrfs_device *scrub_dev, u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length, u64 dev_offset, int is_dev_replace) { struct btrfs_mapping_tree *map_tree = &sctx->dev_root->fs_info->mapping_tree; struct map_lookup *map; struct extent_map *em; int i; int ret = 0; read_lock(&map_tree->map_tree.lock); em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1); read_unlock(&map_tree->map_tree.lock); if (!em) return -EINVAL; map = (struct map_lookup *)em->bdev; if (em->start != chunk_offset) goto out; if (em->len < length) goto out; for (i = 0; i < map->num_stripes; ++i) { if (map->stripes[i].dev->bdev == scrub_dev->bdev && map->stripes[i].physical == dev_offset) { ret = scrub_stripe(sctx, map, scrub_dev, i, chunk_offset, length, is_dev_replace); if (ret) goto out; } } out: free_extent_map(em); return ret; } static noinline_for_stack int scrub_enumerate_chunks(struct scrub_ctx *sctx, struct btrfs_device *scrub_dev, u64 start, u64 end, int is_dev_replace) { struct btrfs_dev_extent *dev_extent = NULL; struct btrfs_path *path; struct btrfs_root *root = sctx->dev_root; struct btrfs_fs_info *fs_info = root->fs_info; u64 length; u64 chunk_tree; u64 chunk_objectid; u64 chunk_offset; int ret; int slot; struct extent_buffer *l; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_block_group_cache *cache; struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = 2; path->search_commit_root = 1; path->skip_locking = 1; key.objectid = scrub_dev->devid; key.offset = 0ull; key.type = BTRFS_DEV_EXTENT_KEY; while (1) { ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) break; if (ret > 0) { if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { ret = btrfs_next_leaf(root, path); if (ret) break; } } l = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(l, &found_key, slot); if (found_key.objectid != scrub_dev->devid) break; if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY) break; if (found_key.offset >= end) break; if (found_key.offset < key.offset) break; dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent); length = btrfs_dev_extent_length(l, dev_extent); if (found_key.offset + length <= start) { key.offset = found_key.offset + length; btrfs_release_path(path); continue; } chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent); chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent); chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent); /* * get a reference on the corresponding block group to prevent * the chunk from going away while we scrub it */ cache = btrfs_lookup_block_group(fs_info, chunk_offset); if (!cache) { ret = -ENOENT; break; } dev_replace->cursor_right = found_key.offset + length; dev_replace->cursor_left = found_key.offset; dev_replace->item_needs_writeback = 1; ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid, chunk_offset, length, found_key.offset, is_dev_replace); /* * flush, submit all pending read and write bios, afterwards * wait for them. * Note that in the dev replace case, a read request causes * write requests that are submitted in the read completion * worker. Therefore in the current situation, it is required * that all write requests are flushed, so that all read and * write requests are really completed when bios_in_flight * changes to 0. */ atomic_set(&sctx->wr_ctx.flush_all_writes, 1); scrub_submit(sctx); mutex_lock(&sctx->wr_ctx.wr_lock); scrub_wr_submit(sctx); mutex_unlock(&sctx->wr_ctx.wr_lock); wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0); atomic_set(&sctx->wr_ctx.flush_all_writes, 0); atomic_inc(&fs_info->scrubs_paused); wake_up(&fs_info->scrub_pause_wait); wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0); mutex_lock(&fs_info->scrub_lock); while (atomic_read(&fs_info->scrub_pause_req)) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, atomic_read(&fs_info->scrub_pause_req) == 0); mutex_lock(&fs_info->scrub_lock); } atomic_dec(&fs_info->scrubs_paused); mutex_unlock(&fs_info->scrub_lock); wake_up(&fs_info->scrub_pause_wait); dev_replace->cursor_left = dev_replace->cursor_right; dev_replace->item_needs_writeback = 1; btrfs_put_block_group(cache); if (ret) break; if (is_dev_replace && atomic64_read(&dev_replace->num_write_errors) > 0) { ret = -EIO; break; } if (sctx->stat.malloc_errors > 0) { ret = -ENOMEM; break; } key.offset = found_key.offset + length; btrfs_release_path(path); } btrfs_free_path(path); /* * ret can still be 1 from search_slot or next_leaf, * that's not an error */ return ret < 0 ? ret : 0; } static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx, struct btrfs_device *scrub_dev) { int i; u64 bytenr; u64 gen; int ret; struct btrfs_root *root = sctx->dev_root; if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) return -EIO; gen = root->fs_info->last_trans_committed; for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) { bytenr = btrfs_sb_offset(i); if (bytenr + BTRFS_SUPER_INFO_SIZE > scrub_dev->total_bytes) break; ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr, scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1, bytenr); if (ret) return ret; } wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0); return 0; } /* * get a reference count on fs_info->scrub_workers. start worker if necessary */ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info, int is_dev_replace) { int ret = 0; mutex_lock(&fs_info->scrub_lock); if (fs_info->scrub_workers_refcnt == 0) { if (is_dev_replace) btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1, &fs_info->generic_worker); else btrfs_init_workers(&fs_info->scrub_workers, "scrub", fs_info->thread_pool_size, &fs_info->generic_worker); fs_info->scrub_workers.idle_thresh = 4; ret = btrfs_start_workers(&fs_info->scrub_workers); if (ret) goto out; btrfs_init_workers(&fs_info->scrub_wr_completion_workers, "scrubwrc", fs_info->thread_pool_size, &fs_info->generic_worker); fs_info->scrub_wr_completion_workers.idle_thresh = 2; ret = btrfs_start_workers( &fs_info->scrub_wr_completion_workers); if (ret) goto out; btrfs_init_workers(&fs_info->scrub_nocow_workers, "scrubnc", 1, &fs_info->generic_worker); ret = btrfs_start_workers(&fs_info->scrub_nocow_workers); if (ret) goto out; } ++fs_info->scrub_workers_refcnt; out: mutex_unlock(&fs_info->scrub_lock); return ret; } static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info) { mutex_lock(&fs_info->scrub_lock); if (--fs_info->scrub_workers_refcnt == 0) { btrfs_stop_workers(&fs_info->scrub_workers); btrfs_stop_workers(&fs_info->scrub_wr_completion_workers); btrfs_stop_workers(&fs_info->scrub_nocow_workers); } WARN_ON(fs_info->scrub_workers_refcnt < 0); mutex_unlock(&fs_info->scrub_lock); } int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, u64 end, struct btrfs_scrub_progress *progress, int readonly, int is_dev_replace) { struct scrub_ctx *sctx; int ret; struct btrfs_device *dev; if (btrfs_fs_closing(fs_info)) return -EINVAL; /* * check some assumptions */ if (fs_info->chunk_root->nodesize != fs_info->chunk_root->leafsize) { printk(KERN_ERR "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n", fs_info->chunk_root->nodesize, fs_info->chunk_root->leafsize); return -EINVAL; } if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) { /* * in this case scrub is unable to calculate the checksum * the way scrub is implemented. Do not handle this * situation at all because it won't ever happen. */ printk(KERN_ERR "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n", fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN); return -EINVAL; } if (fs_info->chunk_root->sectorsize != PAGE_SIZE) { /* not supported for data w/o checksums */ printk(KERN_ERR "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lu) fails\n", fs_info->chunk_root->sectorsize, PAGE_SIZE); return -EINVAL; } if (fs_info->chunk_root->nodesize > PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK || fs_info->chunk_root->sectorsize > PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) { /* * would exhaust the array bounds of pagev member in * struct scrub_block */ pr_err("btrfs_scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails\n", fs_info->chunk_root->nodesize, SCRUB_MAX_PAGES_PER_BLOCK, fs_info->chunk_root->sectorsize, SCRUB_MAX_PAGES_PER_BLOCK); return -EINVAL; } ret = scrub_workers_get(fs_info, is_dev_replace); if (ret) return ret; mutex_lock(&fs_info->fs_devices->device_list_mutex); dev = btrfs_find_device(fs_info, devid, NULL, NULL); if (!dev || (dev->missing && !is_dev_replace)) { mutex_unlock(&fs_info->fs_devices->device_list_mutex); scrub_workers_put(fs_info); return -ENODEV; } mutex_lock(&fs_info->scrub_lock); if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); scrub_workers_put(fs_info); return -EIO; } btrfs_dev_replace_lock(&fs_info->dev_replace); if (dev->scrub_device || (!is_dev_replace && btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) { btrfs_dev_replace_unlock(&fs_info->dev_replace); mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); scrub_workers_put(fs_info); return -EINPROGRESS; } btrfs_dev_replace_unlock(&fs_info->dev_replace); sctx = scrub_setup_ctx(dev, is_dev_replace); if (IS_ERR(sctx)) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); scrub_workers_put(fs_info); return PTR_ERR(sctx); } sctx->readonly = readonly; dev->scrub_device = sctx; atomic_inc(&fs_info->scrubs_running); mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); if (!is_dev_replace) { down_read(&fs_info->scrub_super_lock); ret = scrub_supers(sctx, dev); up_read(&fs_info->scrub_super_lock); } if (!ret) ret = scrub_enumerate_chunks(sctx, dev, start, end, is_dev_replace); wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0); atomic_dec(&fs_info->scrubs_running); wake_up(&fs_info->scrub_pause_wait); wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0); if (progress) memcpy(progress, &sctx->stat, sizeof(*progress)); mutex_lock(&fs_info->scrub_lock); dev->scrub_device = NULL; mutex_unlock(&fs_info->scrub_lock); scrub_free_ctx(sctx); scrub_workers_put(fs_info); return ret; } void btrfs_scrub_pause(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; mutex_lock(&fs_info->scrub_lock); atomic_inc(&fs_info->scrub_pause_req); while (atomic_read(&fs_info->scrubs_paused) != atomic_read(&fs_info->scrubs_running)) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, atomic_read(&fs_info->scrubs_paused) == atomic_read(&fs_info->scrubs_running)); mutex_lock(&fs_info->scrub_lock); } mutex_unlock(&fs_info->scrub_lock); } void btrfs_scrub_continue(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; atomic_dec(&fs_info->scrub_pause_req); wake_up(&fs_info->scrub_pause_wait); } void btrfs_scrub_pause_super(struct btrfs_root *root) { down_write(&root->fs_info->scrub_super_lock); } void btrfs_scrub_continue_super(struct btrfs_root *root) { up_write(&root->fs_info->scrub_super_lock); } int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info) { mutex_lock(&fs_info->scrub_lock); if (!atomic_read(&fs_info->scrubs_running)) { mutex_unlock(&fs_info->scrub_lock); return -ENOTCONN; } atomic_inc(&fs_info->scrub_cancel_req); while (atomic_read(&fs_info->scrubs_running)) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, atomic_read(&fs_info->scrubs_running) == 0); mutex_lock(&fs_info->scrub_lock); } atomic_dec(&fs_info->scrub_cancel_req); mutex_unlock(&fs_info->scrub_lock); return 0; } int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info, struct btrfs_device *dev) { struct scrub_ctx *sctx; mutex_lock(&fs_info->scrub_lock); sctx = dev->scrub_device; if (!sctx) { mutex_unlock(&fs_info->scrub_lock); return -ENOTCONN; } atomic_inc(&sctx->cancel_req); while (dev->scrub_device) { mutex_unlock(&fs_info->scrub_lock); wait_event(fs_info->scrub_pause_wait, dev->scrub_device == NULL); mutex_lock(&fs_info->scrub_lock); } mutex_unlock(&fs_info->scrub_lock); return 0; } int btrfs_scrub_progress(struct btrfs_root *root, u64 devid, struct btrfs_scrub_progress *progress) { struct btrfs_device *dev; struct scrub_ctx *sctx = NULL; mutex_lock(&root->fs_info->fs_devices->device_list_mutex); dev = btrfs_find_device(root->fs_info, devid, NULL, NULL); if (dev) sctx = dev->scrub_device; if (sctx) memcpy(progress, &sctx->stat, sizeof(*progress)); mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV; } static void scrub_remap_extent(struct btrfs_fs_info *fs_info, u64 extent_logical, u64 extent_len, u64 *extent_physical, struct btrfs_device **extent_dev, int *extent_mirror_num) { u64 mapped_length; struct btrfs_bio *bbio = NULL; int ret; mapped_length = extent_len; ret = btrfs_map_block(fs_info, READ, extent_logical, &mapped_length, &bbio, 0); if (ret || !bbio || mapped_length < extent_len || !bbio->stripes[0].dev->bdev) { kfree(bbio); return; } *extent_physical = bbio->stripes[0].physical; *extent_mirror_num = bbio->mirror_num; *extent_dev = bbio->stripes[0].dev; kfree(bbio); } static int scrub_setup_wr_ctx(struct scrub_ctx *sctx, struct scrub_wr_ctx *wr_ctx, struct btrfs_fs_info *fs_info, struct btrfs_device *dev, int is_dev_replace) { WARN_ON(wr_ctx->wr_curr_bio != NULL); mutex_init(&wr_ctx->wr_lock); wr_ctx->wr_curr_bio = NULL; if (!is_dev_replace) return 0; WARN_ON(!dev->bdev); wr_ctx->pages_per_wr_bio = min_t(int, SCRUB_PAGES_PER_WR_BIO, bio_get_nr_vecs(dev->bdev)); wr_ctx->tgtdev = dev; atomic_set(&wr_ctx->flush_all_writes, 0); return 0; } static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx) { mutex_lock(&wr_ctx->wr_lock); kfree(wr_ctx->wr_curr_bio); wr_ctx->wr_curr_bio = NULL; mutex_unlock(&wr_ctx->wr_lock); } static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len, int mirror_num, u64 physical_for_dev_replace) { struct scrub_copy_nocow_ctx *nocow_ctx; struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info; nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS); if (!nocow_ctx) { spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); return -ENOMEM; } scrub_pending_trans_workers_inc(sctx); nocow_ctx->sctx = sctx; nocow_ctx->logical = logical; nocow_ctx->len = len; nocow_ctx->mirror_num = mirror_num; nocow_ctx->physical_for_dev_replace = physical_for_dev_replace; nocow_ctx->work.func = copy_nocow_pages_worker; btrfs_queue_worker(&fs_info->scrub_nocow_workers, &nocow_ctx->work); return 0; } static void copy_nocow_pages_worker(struct btrfs_work *work) { struct scrub_copy_nocow_ctx *nocow_ctx = container_of(work, struct scrub_copy_nocow_ctx, work); struct scrub_ctx *sctx = nocow_ctx->sctx; u64 logical = nocow_ctx->logical; u64 len = nocow_ctx->len; int mirror_num = nocow_ctx->mirror_num; u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace; int ret; struct btrfs_trans_handle *trans = NULL; struct btrfs_fs_info *fs_info; struct btrfs_path *path; struct btrfs_root *root; int not_written = 0; fs_info = sctx->dev_root->fs_info; root = fs_info->extent_root; path = btrfs_alloc_path(); if (!path) { spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); not_written = 1; goto out; } trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { not_written = 1; goto out; } ret = iterate_inodes_from_logical(logical, fs_info, path, copy_nocow_pages_for_inode, nocow_ctx); if (ret != 0 && ret != -ENOENT) { pr_warn("iterate_inodes_from_logical() failed: log %llu, phys %llu, len %llu, mir %llu, ret %d\n", logical, physical_for_dev_replace, len, (unsigned long long)mirror_num, ret); not_written = 1; goto out; } out: if (trans && !IS_ERR(trans)) btrfs_end_transaction(trans, root); if (not_written) btrfs_dev_replace_stats_inc(&fs_info->dev_replace. num_uncorrectable_read_errors); btrfs_free_path(path); kfree(nocow_ctx); scrub_pending_trans_workers_dec(sctx); } static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx) { struct scrub_copy_nocow_ctx *nocow_ctx = ctx; struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info; struct btrfs_key key; struct inode *inode; struct page *page; struct btrfs_root *local_root; u64 physical_for_dev_replace; u64 len; unsigned long index; int srcu_index; int ret; int err; key.objectid = root; key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1; srcu_index = srcu_read_lock(&fs_info->subvol_srcu); local_root = btrfs_read_fs_root_no_name(fs_info, &key); if (IS_ERR(local_root)) { srcu_read_unlock(&fs_info->subvol_srcu, srcu_index); return PTR_ERR(local_root); } if (btrfs_root_refs(&local_root->root_item) == 0) { srcu_read_unlock(&fs_info->subvol_srcu, srcu_index); return -ENOENT; } key.type = BTRFS_INODE_ITEM_KEY; key.objectid = inum; key.offset = 0; inode = btrfs_iget(fs_info->sb, &key, local_root, NULL); srcu_read_unlock(&fs_info->subvol_srcu, srcu_index); if (IS_ERR(inode)) return PTR_ERR(inode); /* Avoid truncate/dio/punch hole.. */ mutex_lock(&inode->i_mutex); inode_dio_wait(inode); ret = 0; physical_for_dev_replace = nocow_ctx->physical_for_dev_replace; len = nocow_ctx->len; while (len >= PAGE_CACHE_SIZE) { index = offset >> PAGE_CACHE_SHIFT; again: page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); if (!page) { pr_err("find_or_create_page() failed\n"); ret = -ENOMEM; goto out; } if (PageUptodate(page)) { if (PageDirty(page)) goto next_page; } else { ClearPageError(page); err = extent_read_full_page(&BTRFS_I(inode)-> io_tree, page, btrfs_get_extent, nocow_ctx->mirror_num); if (err) { ret = err; goto next_page; } lock_page(page); /* * If the page has been remove from the page cache, * the data on it is meaningless, because it may be * old one, the new data may be written into the new * page in the page cache. */ if (page->mapping != inode->i_mapping) { page_cache_release(page); goto again; } if (!PageUptodate(page)) { ret = -EIO; goto next_page; } } err = write_page_nocow(nocow_ctx->sctx, physical_for_dev_replace, page); if (err) ret = err; next_page: unlock_page(page); page_cache_release(page); if (ret) break; offset += PAGE_CACHE_SIZE; physical_for_dev_replace += PAGE_CACHE_SIZE; len -= PAGE_CACHE_SIZE; } out: mutex_unlock(&inode->i_mutex); iput(inode); return ret; } static int write_page_nocow(struct scrub_ctx *sctx, u64 physical_for_dev_replace, struct page *page) { struct bio *bio; struct btrfs_device *dev; int ret; DECLARE_COMPLETION_ONSTACK(compl); dev = sctx->wr_ctx.tgtdev; if (!dev) return -EIO; if (!dev->bdev) { printk_ratelimited(KERN_WARNING "btrfs: scrub write_page_nocow(bdev == NULL) is unexpected!\n"); return -EIO; } bio = btrfs_io_bio_alloc(GFP_NOFS, 1); if (!bio) { spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); return -ENOMEM; } bio->bi_private = &compl; bio->bi_end_io = scrub_complete_bio_end_io; bio->bi_size = 0; bio->bi_sector = physical_for_dev_replace >> 9; bio->bi_bdev = dev->bdev; ret = bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); if (ret != PAGE_CACHE_SIZE) { leave_with_eio: bio_put(bio); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS); return -EIO; } btrfsic_submit_bio(WRITE_SYNC, bio); wait_for_completion(&compl); if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) goto leave_with_eio; bio_put(bio); return 0; }