diff options
Diffstat (limited to 'fs/btrfs/scrub.c')
| -rw-r--r-- | fs/btrfs/scrub.c | 3489 |
1 files changed, 3489 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c new file mode 100644 index 00000000000..b6d198f5181 --- /dev/null +++ b/fs/btrfs/scrub.c @@ -0,0 +1,3489 @@ +/* + * 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 <linux/blkdev.h> +#include <linux/ratelimit.h> +#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_nocow_inode { + u64 inum; + u64 offset; + u64 root; + struct list_head list; +}; + +struct scrub_copy_nocow_ctx { + struct scrub_ctx *sctx; + u64 logical; + u64 len; + int mirror_num; + u64 physical_for_dev_replace; + struct list_head inodes; + 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 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, + struct scrub_copy_nocow_ctx *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_blocked_if_needed(struct btrfs_fs_info *fs_info); +static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info); + + +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); +} + +static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info) +{ + 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); + } +} + +static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info) +{ + atomic_inc(&fs_info->scrubs_paused); + wake_up(&fs_info->scrub_pause_wait); + + mutex_lock(&fs_info->scrub_lock); + __scrub_blocked_if_needed(fs_info); + atomic_dec(&fs_info->scrubs_paused); + mutex_unlock(&fs_info->scrub_lock); + + wake_up(&fs_info->scrub_pause_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); + + /* + * check if @scrubs_running=@scrubs_paused condition + * inside wait_event() is not an atomic operation. + * which means we may inc/dec @scrub_running/paused + * at any time. Let's wake up @scrub_pause_wait as + * much as we can to let commit transaction blocked less. + */ + wake_up(&fs_info->scrub_pause_wait); + + 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; + btrfs_init_work(&sbio->work, scrub_bio_end_io_worker, + NULL, NULL); + + 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, &found_key, 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); + + 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_path *path; + int uncorrectable = 0; + + fixup = container_of(work, struct scrub_fixup_nodatasum, work); + sctx = fixup->sctx; + + 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) { + ASSERT(!sctx->is_dev_replace); + goto out; + } + + 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); + btrfs_init_work(&fixup_nodatasum->work, scrub_fixup_nodatasum, + NULL, NULL); + btrfs_queue_work(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]; + + 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_iter.bi_sector = page->physical >> 9; + + bio_add_page(bio, page->page, PAGE_SIZE, 0); + if (btrfsic_submit_bio_wait(READ, bio)) + 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 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; + + 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_iter.bi_sector = page_bad->physical >> 9; + + ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0); + if (PAGE_SIZE != ret) { + bio_put(bio); + return -EIO; + } + + if (btrfsic_submit_bio_wait(WRITE, bio)) { + 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_iter.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; + + btrfs_init_work(&sbio->work, scrub_wr_bio_end_io_worker, NULL, NULL); + btrfs_queue_work(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_iter.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_work(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; +} + +/* + * Given a physical address, this will calculate it's + * logical offset. if this is a parity stripe, it will return + * the most left data stripe's logical offset. + * + * return 0 if it is a data stripe, 1 means parity stripe. + */ +static int get_raid56_logic_offset(u64 physical, int num, + struct map_lookup *map, u64 *offset) +{ + int i; + int j = 0; + u64 stripe_nr; + u64 last_offset; + int stripe_index; + int rot; + + last_offset = (physical - map->stripes[num].physical) * + nr_data_stripes(map); + *offset = last_offset; + for (i = 0; i < nr_data_stripes(map); i++) { + *offset = last_offset + i * map->stripe_len; + + stripe_nr = *offset; + do_div(stripe_nr, map->stripe_len); + do_div(stripe_nr, nr_data_stripes(map)); + + /* Work out the disk rotation on this stripe-set */ + rot = do_div(stripe_nr, map->num_stripes); + /* calculate which stripe this data locates */ + rot += i; + stripe_index = rot % map->num_stripes; + if (stripe_index == num) + return 0; + if (stripe_index < num) + j++; + } + *offset = last_offset + j * map->stripe_len; + return 1; +} + +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 physical_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 = 0; + + nstripes = length; + physical = map->stripes[num].physical; + 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 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | + BTRFS_BLOCK_GROUP_RAID6)) { + get_raid56_logic_offset(physical, num, map, &offset); + increment = map->stripe_len * nr_data_stripes(map); + mirror_num = 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; + physical_end = physical + nstripes * map->stripe_len; + if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | + BTRFS_BLOCK_GROUP_RAID6)) { + get_raid56_logic_offset(physical_end, num, + map, &logic_end); + logic_end += base; + } else { + logic_end = logical + increment * nstripes; + } + wait_event(sctx->list_wait, + atomic_read(&sctx->bios_in_flight) == 0); + scrub_blocked_if_needed(fs_info); + + /* 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 = logic_end; + 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 = logic_end; + 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); + + + /* + * 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 + */ + ret = 0; + while (physical < physical_end) { + /* for raid56, we skip parity stripe */ + if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | + BTRFS_BLOCK_GROUP_RAID6)) { + ret = get_raid56_logic_offset(physical, num, + map, &logical); + logical += base; + if (ret) + goto skip; + } + /* + * 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); + scrub_blocked_if_needed(fs_info); + } + + if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) + key.type = BTRFS_METADATA_ITEM_KEY; + else + key.type = BTRFS_EXTENT_ITEM_KEY; + key.objectid = logical; + 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_extent_item(root, path, 0); + 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)) { + btrfs_err(fs_info, + "scrub: tree block %llu spanning " + "stripes, ignored. logical=%llu", + 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) { + if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | + BTRFS_BLOCK_GROUP_RAID6)) { + /* + * loop until we find next data stripe + * or we have finished all stripes. + */ + do { + physical += map->stripe_len; + ret = get_raid56_logic_offset( + physical, num, + map, &logical); + logical += base; + } while (physical < physical_end && ret); + } else { + physical += map->stripe_len; + logical += increment; + } + if (logical < key.objectid + bytes) { + cond_resched(); + goto again; + } + + if (physical >= physical_end) { + stop_loop = 1; + break; + } + } +next: + path->slots[0]++; + } + btrfs_release_path(path); +skip: + 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) + goto skip; + + 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); + + /* some chunks are removed but not committed to disk yet, + * continue scrubbing */ + if (!cache) + goto skip; + + 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_inc(&fs_info->scrubs_paused); + wake_up(&fs_info->scrub_pause_wait); + + /* + * must be called before we decrease @scrub_paused. + * make sure we don't block transaction commit while + * we are waiting pending workers finished. + */ + wait_event(sctx->list_wait, + atomic_read(&sctx->workers_pending) == 0); + atomic_set(&sctx->wr_ctx.flush_all_writes, 0); + + mutex_lock(&fs_info->scrub_lock); + __scrub_blocked_if_needed(fs_info); + atomic_dec(&fs_info->scrubs_paused); + mutex_unlock(&fs_info->scrub_lock); + wake_up(&fs_info->scrub_pause_wait); + + 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; + } + + dev_replace->cursor_left = dev_replace->cursor_right; + dev_replace->item_needs_writeback = 1; +skip: + 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; + int flags = WQ_FREEZABLE | WQ_UNBOUND; + int max_active = fs_info->thread_pool_size; + + if (fs_info->scrub_workers_refcnt == 0) { + if (is_dev_replace) + fs_info->scrub_workers = + btrfs_alloc_workqueue("btrfs-scrub", flags, + 1, 4); + else + fs_info->scrub_workers = + btrfs_alloc_workqueue("btrfs-scrub", flags, + max_active, 4); + if (!fs_info->scrub_workers) { + ret = -ENOMEM; + goto out; + } + fs_info->scrub_wr_completion_workers = + btrfs_alloc_workqueue("btrfs-scrubwrc", flags, + max_active, 2); + if (!fs_info->scrub_wr_completion_workers) { + ret = -ENOMEM; + goto out; + } + fs_info->scrub_nocow_workers = + btrfs_alloc_workqueue("btrfs-scrubnc", flags, 1, 0); + if (!fs_info->scrub_nocow_workers) { + ret = -ENOMEM; + goto out; + } + } + ++fs_info->scrub_workers_refcnt; +out: + return ret; +} + +static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info) +{ + if (--fs_info->scrub_workers_refcnt == 0) { + btrfs_destroy_workqueue(fs_info->scrub_workers); + btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers); + btrfs_destroy_workqueue(fs_info->scrub_nocow_workers); + } + WARN_ON(fs_info->scrub_workers_refcnt < 0); +} + +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) { + btrfs_err(fs_info, + "scrub: size assumption nodesize == leafsize (%d == %d) fails", + 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. + */ + btrfs_err(fs_info, + "scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails", + 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 */ + btrfs_err(fs_info, + "scrub: size assumption sectorsize != PAGE_SIZE " + "(%d != %lu) fails", + 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 + */ + btrfs_err(fs_info, "scrub: size assumption nodesize and sectorsize " + "<= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails", + fs_info->chunk_root->nodesize, + SCRUB_MAX_PAGES_PER_BLOCK, + fs_info->chunk_root->sectorsize, + SCRUB_MAX_PAGES_PER_BLOCK); + return -EINVAL; + } + + + 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); + 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); + 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); + return -EINPROGRESS; + } + btrfs_dev_replace_unlock(&fs_info->dev_replace); + + ret = scrub_workers_get(fs_info, is_dev_replace); + if (ret) { + mutex_unlock(&fs_info->scrub_lock); + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + return ret; + } + + 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; + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + + /* + * checking @scrub_pause_req here, we can avoid + * race between committing transaction and scrubbing. + */ + __scrub_blocked_if_needed(fs_info); + atomic_inc(&fs_info->scrubs_running); + mutex_unlock(&fs_info->scrub_lock); + + if (!is_dev_replace) { + /* + * by holding device list mutex, we can + * kick off writing super in log tree sync. + */ + mutex_lock(&fs_info->fs_devices->device_list_mutex); + ret = scrub_supers(sctx, dev); + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + } + + 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; + scrub_workers_put(fs_info); + mutex_unlock(&fs_info->scrub_lock); + + scrub_free_ctx(sctx); + + 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); +} + +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; + btrfs_init_work(&nocow_ctx->work, copy_nocow_pages_worker, NULL, NULL); + INIT_LIST_HEAD(&nocow_ctx->inodes); + btrfs_queue_work(fs_info->scrub_nocow_workers, + &nocow_ctx->work); + + return 0; +} + +static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx) +{ + struct scrub_copy_nocow_ctx *nocow_ctx = ctx; + struct scrub_nocow_inode *nocow_inode; + + nocow_inode = kzalloc(sizeof(*nocow_inode), GFP_NOFS); + if (!nocow_inode) + return -ENOMEM; + nocow_inode->inum = inum; + nocow_inode->offset = offset; + nocow_inode->root = root; + list_add_tail(&nocow_inode->list, &nocow_ctx->inodes); + return 0; +} + +#define COPY_COMPLETE 1 + +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, + record_inode_for_nocow, nocow_ctx); + if (ret != 0 && ret != -ENOENT) { + btrfs_warn(fs_info, "iterate_inodes_from_logical() failed: log %llu, " + "phys %llu, len %llu, mir %u, ret %d", + logical, physical_for_dev_replace, len, mirror_num, + ret); + not_written = 1; + goto out; + } + + btrfs_end_transaction(trans, root); + trans = NULL; + while (!list_empty(&nocow_ctx->inodes)) { + struct scrub_nocow_inode *entry; + entry = list_first_entry(&nocow_ctx->inodes, + struct scrub_nocow_inode, + list); + list_del_init(&entry->list); + ret = copy_nocow_pages_for_inode(entry->inum, entry->offset, + entry->root, nocow_ctx); + kfree(entry); + if (ret == COPY_COMPLETE) { + ret = 0; + break; + } else if (ret) { + break; + } + } +out: + while (!list_empty(&nocow_ctx->inodes)) { + struct scrub_nocow_inode *entry; + entry = list_first_entry(&nocow_ctx->inodes, + struct scrub_nocow_inode, + list); + list_del_init(&entry->list); + kfree(entry); + } + 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, + struct scrub_copy_nocow_ctx *nocow_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; + struct btrfs_ordered_extent *ordered; + struct extent_map *em; + struct extent_state *cached_state = NULL; + struct extent_io_tree *io_tree; + u64 physical_for_dev_replace; + u64 len = nocow_ctx->len; + u64 lockstart = offset, lockend = offset + len - 1; + unsigned long index; + int srcu_index; + int ret = 0; + int err = 0; + + 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); + } + + 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); + + physical_for_dev_replace = nocow_ctx->physical_for_dev_replace; + io_tree = &BTRFS_I(inode)->io_tree; + + lock_extent_bits(io_tree, lockstart, lockend, 0, &cached_state); + ordered = btrfs_lookup_ordered_range(inode, lockstart, len); + if (ordered) { + btrfs_put_ordered_extent(ordered); + goto out_unlock; + } + + em = btrfs_get_extent(inode, NULL, 0, lockstart, len, 0); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out_unlock; + } + + /* + * This extent does not actually cover the logical extent anymore, + * move on to the next inode. + */ + if (em->block_start > nocow_ctx->logical || + em->block_start + em->block_len < nocow_ctx->logical + len) { + free_extent_map(em); + goto out_unlock; + } + free_extent_map(em); + + while (len >= PAGE_CACHE_SIZE) { + index = offset >> PAGE_CACHE_SHIFT; +again: + page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); + if (!page) { + btrfs_err(fs_info, "find_or_create_page() failed"); + ret = -ENOMEM; + goto out; + } + + if (PageUptodate(page)) { + if (PageDirty(page)) + goto next_page; + } else { + ClearPageError(page); + err = extent_read_full_page_nolock(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) { + unlock_page(page); + 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; + } + ret = COPY_COMPLETE; +out_unlock: + unlock_extent_cached(io_tree, lockstart, lockend, &cached_state, + GFP_NOFS); +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; + + 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_iter.bi_size = 0; + bio->bi_iter.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; + } + + if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) + goto leave_with_eio; + + bio_put(bio); + return 0; +} |