From 662d1dddcad79839f1cbc13cb0be3ec326af2933 Mon Sep 17 00:00:00 2001 From: Gui Hecheng Date: Wed, 26 Nov 2014 10:43:41 +0800 Subject: [PATCH] btrfs-progs: convert: fix unable to rollback case with removed empty block groups Run fstests: btrfs/012 will fail with message: unable to do rollback It is because the rollback function checks sequentially each piece of space to map to a certain block group. If some piece doesn't, rollback refuses to continue. After kernel commit: commit 47ab2a6c689913db23ccae38349714edf8365e0a Btrfs: remove empty block groups automatically Empty block groups are removed, so there are possible gaps: |--block group 1--| |--block group 2--| ^ | gap So the piece of space of the gap belongs to a removed empty block group, and rollback should detect this case, and feel free to continue. Signed-off-by: Gui Hecheng Signed-off-by: David Sterba --- btrfs-convert.c | 13 +++++++++++-- volumes.c | 2 ++ 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/btrfs-convert.c b/btrfs-convert.c index 6e2ab0f2..4c6c793a 100644 --- a/btrfs-convert.c +++ b/btrfs-convert.c @@ -2418,8 +2418,17 @@ static int may_rollback(struct btrfs_root *root) while (1) { ret = btrfs_map_block(&info->mapping_tree, WRITE, bytenr, &length, &multi, 0, NULL); - if (ret) + if (ret) { + if (ret == -ENOENT) { + /* removed block group at the tail */ + if (length == (u64)-1) + break; + + /* removed block group in the middle */ + goto next; + } goto fail; + } num_stripes = multi->num_stripes; physical = multi->stripes[0].physical; @@ -2427,7 +2436,7 @@ static int may_rollback(struct btrfs_root *root) if (num_stripes != 1 || physical != bytenr) goto fail; - +next: bytenr += length; if (bytenr >= total_bytes) break; diff --git a/volumes.c b/volumes.c index a1fd162a..a988cdbc 100644 --- a/volumes.c +++ b/volumes.c @@ -1318,10 +1318,12 @@ again: ce = search_cache_extent(&map_tree->cache_tree, logical); if (!ce) { kfree(multi); + *length = (u64)-1; return -ENOENT; } if (ce->start > logical) { kfree(multi); + *length = ce->start - logical; return -ENOENT; }