xfs: scrub should flag dir/attr offsets that aren't mappable with xfs_dablk_t

Teach scrub to flag extent maps that exceed the range that can be mapped
with a xfs_dablk_t.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_types.c

@@ -204,3 +204,14 @@ xfs_verify_icount(
 	xfs_icount_range(mp, &min, &max);
 	return icount >= min && icount <= max;
 }
+
+/* Sanity-checking of dir/attr block offsets. */
+bool
+xfs_verify_dablk(
+	struct xfs_mount	*mp,
+	xfs_fileoff_t		dabno)
+{
+	xfs_dablk_t		max_dablk = -1U;
+
+	return dabno <= max_dablk;
+}

fs/xfs/libxfs/xfs_types.h

@@ -188,5 +188,6 @@ 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);
 bool xfs_verify_rtbno(struct xfs_mount *mp, xfs_rtblock_t rtbno);
 bool xfs_verify_icount(struct xfs_mount *mp, unsigned long long icount);
+bool xfs_verify_dablk(struct xfs_mount *mp, xfs_fileoff_t off);
 
 #endif	/* __XFS_TYPES_H__ */

fs/xfs/scrub/bmap.c

@@ -281,6 +281,31 @@ xchk_bmap_extent_xref(
 	xchk_ag_free(info->sc, &info->sc->sa);
 }
 
+/*
+ * Directories and attr forks should never have blocks that can't be addressed
+ * by a xfs_dablk_t.
+ */
+STATIC void
+xchk_bmap_dirattr_extent(
+	struct xfs_inode	*ip,
+	struct xchk_bmap_info	*info,
+	struct xfs_bmbt_irec	*irec)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	xfs_fileoff_t		off;
+
+	if (!S_ISDIR(VFS_I(ip)->i_mode) && info->whichfork != XFS_ATTR_FORK)
+		return;
+
+	if (!xfs_verify_dablk(mp, irec->br_startoff))
+		xchk_fblock_set_corrupt(info->sc, info->whichfork,
+				irec->br_startoff);
+
+	off = irec->br_startoff + irec->br_blockcount - 1;
+	if (!xfs_verify_dablk(mp, off))
+		xchk_fblock_set_corrupt(info->sc, info->whichfork, off);
+}
+
 /* Scrub a single extent record. */
 STATIC int
 xchk_bmap_extent(
@@ -305,6 +330,8 @@ xchk_bmap_extent(
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
 				irec->br_startoff);
 
+	xchk_bmap_dirattr_extent(ip, info, irec);
+
 	/* There should never be a "hole" extent in either extent list. */
 	if (irec->br_startblock == HOLESTARTBLOCK)
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,