xfs: refactor AGI unlinked bucket updates

Split the AGI unlinked bucket updates into a separate function.  No
functional changes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 45 insertions, 20 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 8a39d80f4863..f1de80e8b9a6 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1907,6 +1907,43 @@ xfs_inactive(
 }
 
 /*
+ * Point the AGI unlinked bucket at an inode and log the results.  The caller
+ * is responsible for validating the old value.
+ */
+STATIC int
+xfs_iunlink_update_bucket(
+	struct xfs_trans	*tp,
+	xfs_agnumber_t		agno,
+	struct xfs_buf		*agibp,
+	unsigned int		bucket_index,
+	xfs_agino_t		new_agino)
+{
+	struct xfs_agi		*agi = XFS_BUF_TO_AGI(agibp);
+	xfs_agino_t		old_value;
+	int			offset;
+
+	ASSERT(xfs_verify_agino_or_null(tp->t_mountp, agno, new_agino));
+
+	old_value = be32_to_cpu(agi->agi_unlinked[bucket_index]);
+	trace_xfs_iunlink_update_bucket(tp->t_mountp, agno, bucket_index,
+			old_value, new_agino);
+
+	/*
+	 * We should never find the head of the list already set to the value
+	 * passed in because either we're adding or removing ourselves from the
+	 * head of the list.
+	 */
+	if (old_value == new_agino)
+		return -EFSCORRUPTED;
+
+	agi->agi_unlinked[bucket_index] = cpu_to_be32(new_agino);
+	offset = offsetof(struct xfs_agi, agi_unlinked) +
+			(sizeof(xfs_agino_t) * bucket_index);
+	xfs_trans_log_buf(tp, agibp, offset, offset + sizeof(xfs_agino_t) - 1);
+	return 0;
+}
+
+/*
  * This is called when the inode's link count goes to 0 or we are creating a
  * tmpfile via O_TMPFILE. In the case of a tmpfile, @ignore_linkcount will be
  * set to true as the link count is dropped to zero by the VFS after we've
@@ -1973,16 +2010,8 @@ xfs_iunlink(
 		xfs_inobp_check(mp, ibp);
 	}
 
-	/*
-	 * Point the bucket head pointer at the inode being inserted.
-	 */
-	ASSERT(agino != 0);
-	agi->agi_unlinked[bucket_index] = cpu_to_be32(agino);
-	offset = offsetof(xfs_agi_t, agi_unlinked) +
-		(sizeof(xfs_agino_t) * bucket_index);
-	xfs_trans_log_buf(tp, agibp, offset,
-			  (offset + sizeof(xfs_agino_t) - 1));
-	return 0;
+	/* Point the head of the list to point to this inode. */
+	return xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index, agino);
 }
 
 /*
@@ -2058,16 +2087,12 @@ xfs_iunlink_remove(
 		} else {
 			xfs_trans_brelse(tp, ibp);
 		}
-		/*
-		 * Point the bucket head pointer at the next inode.
-		 */
-		ASSERT(next_agino != 0);
-		ASSERT(next_agino != agino);
-		agi->agi_unlinked[bucket_index] = cpu_to_be32(next_agino);
-		offset = offsetof(xfs_agi_t, agi_unlinked) +
-			(sizeof(xfs_agino_t) * bucket_index);
-		xfs_trans_log_buf(tp, agibp, offset,
-				  (offset + sizeof(xfs_agino_t) - 1));
+
+		/* Point the head of the list to the next unlinked inode. */
+		error = xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
+				next_agino);
+		if (error)
+			return error;
 	} else {
 		/*
 		 * We need to search the list for the inode being freed.