btrfs: release metadata before running delayed refs

Source: linux-mvista-2.4
MR: 96580, 00000
Type: Integration
Disposition: Merged from linux-mvista-2.4
ChangeID: 85df1f9f8fb0c9c4801f5cc8ab1b25e77c1f06cd
Description:

We want to release the unused reservation we have since it refills the
delayed refs reserve, which will make everything go smoother when
running the delayed refs if we're short on our reservation.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Armin Kuster <akuster@mvista.com>
Signed-off-by: Jeremy Puhlman <jpuhlman@mvista.com>

fs/btrfs/transaction.c

@@ -1955,6 +1955,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 		return ret;
 	}
 
+	btrfs_trans_release_metadata(trans, fs_info);
+	trans->block_rsv = NULL;
+
 	/* make a pass through all the delayed refs we have so far
 	 * any runnings procs may add more while we are here
 	 */
@@ -1964,9 +1967,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 		return ret;
 	}
 
-	btrfs_trans_release_metadata(trans, fs_info);
-	trans->block_rsv = NULL;
-
 	cur_trans = trans->transaction;
 
 	/*