[PATCH 3.16 081/366] btrfs: Handle error from btrfs_uuid_tree_rem call in _btrfs_ioctl_set_received_subvol

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nikolay Borisov <nbori...@suse.com>

commit d87ff75863e92a500538ab53318c5740f196631e upstream.

As with every function which deals with modifying the btree
btrfs_uuid_tree_rem can fail for any number of reasons (ie. EIO/ENOMEM).
Handle return error value from this function gracefully by aborting the
transaction.

Fixes: dd5f9615fc5c ("Btrfs: maintain subvolume items in the UUID tree")
Signed-off-by: Nikolay Borisov <nbori...@suse.com>
Reviewed-by: David Sterba <dste...@suse.com>
Signed-off-by: David Sterba <dste...@suse.com>
[bwh: Backported to 3.16:
 - btrfs_{abort,end}_transaction() take a pointer to btrfs_root
 - Adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5051,11 +5051,17 @@ static long _btrfs_ioctl_set_received_su
        received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
                                       BTRFS_UUID_SIZE);
        if (received_uuid_changed &&
-           !btrfs_is_empty_uuid(root_item->received_uuid))
-               btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
-                                   root_item->received_uuid,
-                                   BTRFS_UUID_KEY_RECEIVED_SUBVOL,
-                                   root->root_key.objectid);
+           !btrfs_is_empty_uuid(root_item->received_uuid)) {
+               ret = btrfs_uuid_tree_rem(trans, root->fs_info->uuid_root,
+                                         root_item->received_uuid,
+                                         BTRFS_UUID_KEY_RECEIVED_SUBVOL,
+                                         root->root_key.objectid);
+               if (ret && ret != -ENOENT) {
+                       btrfs_abort_transaction(trans, root, ret);
+                       btrfs_end_transaction(trans, root);
+                       goto out;
+               }
+       }
        memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
        btrfs_set_root_stransid(root_item, sa->stransid);
        btrfs_set_root_rtransid(root_item, sa->rtransid);