xfs_repair: validate alignment of inherited rt extent hints

If we encounter a directory that has been configured to pass on an
extent size hint to a new realtime file and the hint isn't an integer
multiple of the rt extent size, we should turn off the hint because that
is a misconfiguration.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/repair/dinode.c b/repair/dinode.c
index 291c5807372d50acb8c8c469ac5219e5eb78e53d..1275c90b00bf338c6f83cb7f3495fa3a244f5f12 100644 (file)
--- a/repair/dinode.c
+++ b/repair/dinode.c
@@ -2178,6 +2178,31 @@ _("Bad %s nsec %u on inode %" PRIu64 ", "), name, be32_to_cpu(t->t_nsec), lino);
                *dirty = 1;
        }
 }
+/*
+ * Inode verifiers on older kernels don't check that the extent size hint is an
+ * integer multiple of the rt extent size on a directory with both rtinherit
+ * and extszinherit flags set.  If we encounter a directory that is
+ * misconfigured in this way, or a regular file that inherited a bad hint from
+ * a directory, clear the hint.
+ */
+static bool
+zap_bad_rt_extsize_hint(
+       struct xfs_mount        *mp,
+       struct xfs_dinode       *dino)
+{
+       uint16_t                diflags = be16_to_cpu(dino->di_flags);
+
+       if (!(diflags & XFS_DIFLAG_REALTIME) &&
+           !(diflags & XFS_DIFLAG_RTINHERIT))
+               return false;
+
+       if (!(diflags & XFS_DIFLAG_EXTSIZE) &&
+           !(diflags & XFS_DIFLAG_EXTSZINHERIT))
+               return false;
+
+       return (be32_to_cpu(dino->di_extsize) % mp->m_sb.sb_rextsize) != 0;
+}
+
 
 /*
  * returns 0 if the inode is ok, 1 if the inode is corrupt
@@ -2694,7 +2719,8 @@ _("bad (negative) size %" PRId64 " on inode %" PRIu64 "\n"),
         * only regular files with REALTIME or EXTSIZE flags set can have
         * extsize set, or directories with EXTSZINHERIT.
         */
-       if (libxfs_inode_validate_extsize(mp,
+       if (zap_bad_rt_extsize_hint(mp, dino) ||
+           libxfs_inode_validate_extsize(mp,
                        be32_to_cpu(dino->di_extsize),
                        be16_to_cpu(dino->di_mode),
                        be16_to_cpu(dino->di_flags)) != NULL) {