Btrfs: cleanup reloc roots properly on error

I was hitting the BUG_ON() at the end of merge_reloc_roots() because we were
aborting the transaction at some point previously and then getting an error when
we tried to drop the reloc root.  I fixed btrfs_drop_snapshot to re-add us to
the dead roots list if we failed, but this isn't the right thing to do for reloc
roots since it uses root->root_list for it's own stuff in order to know what
needs to be cleaned up.  So fix btrfs_drop_snapshot to only do the re-add if we
aren't dropping for reloc, and handle errors from merge_reloc_root() by dropping
the reloc root we are processing since it won't be on the list of roots to
cleanup.  With this patch my reproducer no longer panics.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This commit is contained in:
Josef Bacik 2013-07-23 16:57:15 -04:00 committed by Chris Mason
parent 50f1319cb5
commit b37b39cd6b
2 changed files with 7 additions and 2 deletions

View File

@ -7696,7 +7696,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
* don't have it in the radix (like when we recover after a power fail
* or unmount) so we don't leak memory.
*/
if (root_dropped == false)
if (!for_reloc && root_dropped == false)
btrfs_add_dead_root(root);
if (err)
btrfs_std_error(root->fs_info, err);

View File

@ -2314,8 +2314,13 @@ int merge_reloc_roots(struct reloc_control *rc)
BUG_ON(root->reloc_root != reloc_root);
ret = merge_reloc_root(rc, root);
if (ret)
if (ret) {
__update_reloc_root(reloc_root, 1);
free_extent_buffer(reloc_root->node);
free_extent_buffer(reloc_root->commit_root);
kfree(reloc_root);
goto out;
}
} else {
list_del_init(&reloc_root->root_list);
}