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@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
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;
if (num_stripes != 1 || physical != bytenr)
goto fail;
-
+next:
bytenr += length;
if (bytenr >= total_bytes)
break;
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;
}