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 <guihc.fnst@xxxxxxxxxxxxxx>
---
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 a544fc6..504c7b3 100644
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -2368,8 +2368,17 @@ 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;
@@ -2377,7 +2386,7 @@ 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 a1fd162..a988cdb 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;
}
--
1.8.1.4
--
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