btrfs: handle logged extent failure properly

If we're allocating a logged extent we attempt to insert an extent
record for the file extent directly.  We increase
space_info->bytes_reserved, because the extent entry addition will call
btrfs_update_block_group(), which will convert the ->bytes_reserved to
->bytes_used.  However if we fail at any point while inserting the
extent entry we will bail and leave space on ->bytes_reserved, which
will trigger a WARN_ON() on umount.  Fix this by pinning the space if we
fail to insert, which is what happens in every other failure case that
involves adding the extent entry.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 0163fdd59f8f2156fd58c65e8bdbceb3ae5dec3a..a7bc66121330e1d4d428c93775c2d832041c7d18 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4430,6 +4430,8 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
 
        ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
                                         offset, ins, 1);
+       if (ret)
+               btrfs_pin_extent(fs_info, ins->objectid, ins->offset, 1);
        btrfs_put_block_group(block_group);
        return ret;
 }