xfs: refactor inode update in iunlink_remove

In xfs_iunlink_remove we have two identical calls to
xfs_iunlink_update_inode, so move it out of the if statement to simplify
the code some more.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/xfs_inode.c

@@ -2189,6 +2189,7 @@ xfs_iunlink_remove(
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
 	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
 	xfs_agino_t		next_agino;
+	xfs_agino_t		head_agino;
 	short			bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
 	int			error;
 
@@ -2202,23 +2203,23 @@ xfs_iunlink_remove(
 	 * Get the index into the agi hash table for the list this inode will
 	 * go on.  Make sure the head pointer isn't garbage.
 	 */
-	next_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
-	if (!xfs_verify_agino(mp, agno, next_agino)) {
+	head_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
+	if (!xfs_verify_agino(mp, agno, head_agino)) {
 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
 				agi, sizeof(*agi));
 		return -EFSCORRUPTED;
 	}
 
-	if (next_agino == agino) {
-		/*
-		 * We're at the head of the list.  Get the inode's on-disk
-		 * buffer to see if there is anyone after us on the list.
-		 */
-		error = xfs_iunlink_update_inode(tp, ip, agno, NULLAGINO,
-				&next_agino);
-		if (error)
-			return error;
+	/*
+	 * Set our inode's next_unlinked pointer to NULL and then return
+	 * the old pointer value so that we can update whatever was previous
+	 * to us in the list to point to whatever was next in the list.
+	 */
+	error = xfs_iunlink_update_inode(tp, ip, agno, NULLAGINO, &next_agino);
+	if (error)
+		return error;
 
+	if (head_agino == agino) {
 		/* Point the head of the list to the next unlinked inode. */
 		error = xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
 				next_agino);
@@ -2229,20 +2230,11 @@ xfs_iunlink_remove(
 		xfs_agino_t	prev_agino;
 
 		/* We need to search the list for the inode being freed. */
-		error = xfs_iunlink_map_prev(tp, agno, next_agino, agino,
+		error = xfs_iunlink_map_prev(tp, agno, head_agino, agino,
 				&prev_agino, &imap, &last_dip, &last_ibp);
 		if (error)
 			return error;
 
-		/*
-		 * Now last_ibp points to the buffer previous to us on the
-		 * unlinked list.  Pull us from the list.
-		 */
-		error = xfs_iunlink_update_inode(tp, ip, agno, NULLAGINO,
-				&next_agino);
-		if (error)
-			return error;
-
 		/* Point the previous inode on the list to the next inode. */
 		xfs_iunlink_update_dinode(tp, agno, prev_agino, last_ibp,
 				last_dip, &imap, next_agino);