xfs: add xfs_verify_agino_or_null helper

Add a new helper to check that a per-AG inode pointer is either null or
points somewhere valid within that AG.

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

3 files changed, 16 insertions, 2 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 09d9c8cfa4a0..82c4374acb4c 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -99,8 +99,7 @@ xfs_inode_buf_verify(
                 unlinked_ino = be32_to_cpu(dip->di_next_unlinked);
                 di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
                         xfs_dinode_good_version(mp, dip->di_version) &&
-                        (unlinked_ino == NULLAGINO ||
-                         xfs_verify_agino(mp, agno, unlinked_ino));
+                        xfs_verify_agino_or_null(mp, agno, unlinked_ino);
                 if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
                                                 XFS_ERRTAG_ITOBP_INOTOBP))) {
                         if (readahead) {
diff --git a/fs/xfs/libxfs/xfs_types.c b/fs/xfs/libxfs/xfs_types.c
index 451608b5a37b..de310712dd6d 100644
--- a/fs/xfs/libxfs/xfs_types.c
+++ b/fs/xfs/libxfs/xfs_types.c
@@ -116,6 +116,19 @@ xfs_verify_agino(
 }
 
 /*
+ * Verify that an AG inode number pointer neither points outside the AG
+ * nor points at static metadata, or is NULLAGINO.
+ */
+bool
+xfs_verify_agino_or_null(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_agino_t             agino)
+{
+        return agino == NULLAGINO || xfs_verify_agino(mp, agno, agino);
+}
+
+/*
  * Verify that an FS inode number pointer neither points outside the
  * filesystem nor points at static AG metadata.
  */
diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
index 704b4f308780..c5a25403b4db 100644
--- a/fs/xfs/libxfs/xfs_types.h
+++ b/fs/xfs/libxfs/xfs_types.h
@@ -183,6 +183,8 @@ void xfs_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
                 xfs_agino_t *first, xfs_agino_t *last);
 bool xfs_verify_agino(struct xfs_mount *mp, xfs_agnumber_t agno,
                 xfs_agino_t agino);
+bool xfs_verify_agino_or_null(struct xfs_mount *mp, xfs_agnumber_t agno,
+                xfs_agino_t agino);
 bool xfs_verify_ino(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_verify_dir_ino(struct xfs_mount *mp, xfs_ino_t ino);