diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/scrub.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 21de630b0730..fd266a2d15ec 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3577,17 +3577,27 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, * This can easily boost the amount of SYSTEM chunks if cleaner * thread can't be triggered fast enough, and use up all space * of btrfs_super_block::sys_chunk_array + * + * While for dev replace, we need to try our best to mark block + * group RO, to prevent race between: + * - Write duplication + * Contains latest data + * - Scrub copy + * Contains data from commit tree + * + * If target block group is not marked RO, nocow writes can + * be overwritten by scrub copy, causing data corruption. + * So for dev-replace, it's not allowed to continue if a block + * group is not RO. */ - ret = btrfs_inc_block_group_ro(cache, false); - scrub_pause_off(fs_info); - + ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace); if (ret == 0) { ro_set = 1; - } else if (ret == -ENOSPC) { + } else if (ret == -ENOSPC && !sctx->is_dev_replace) { /* * btrfs_inc_block_group_ro return -ENOSPC when it * failed in creating new chunk for metadata. - * It is not a problem for scrub/replace, because + * It is not a problem for scrub, because * metadata are always cowed, and our scrub paused * commit_transactions. */ @@ -3596,9 +3606,22 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, btrfs_warn(fs_info, "failed setting block group ro: %d", ret); btrfs_put_block_group(cache); + scrub_pause_off(fs_info); break; } + /* + * Now the target block is marked RO, wait for nocow writes to + * finish before dev-replace. + * COW is fine, as COW never overwrites extents in commit tree. + */ + if (sctx->is_dev_replace) { + btrfs_wait_nocow_writers(cache); + btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, + cache->length); + } + + scrub_pause_off(fs_info); down_write(&dev_replace->rwsem); dev_replace->cursor_right = found_key.offset + length; dev_replace->cursor_left = found_key.offset; |