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.  Old kernels didn't check for this when copying
attributes into new files and would crash in the rt allocator.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
[sandeen: clarify that it is an extent size *hint*]
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/repair/dinode.c b/repair/dinode.c
index 291c5807372d50acb8c8c469ac5219e5eb78e53d..1fd209547d241b855a1f4a9485808351d8a0a935 100644 (file)
--- a/repair/dinode.c
+++ b/repair/dinode.c
@@ -2179,6 +2179,56 @@ _("Bad %s nsec %u on inode %" PRIu64 ", "), name, be32_to_cpu(t->t_nsec), lino);
        }
 }
 
+static void
+validate_extsize(
+       struct xfs_mount        *mp,
+       struct xfs_dinode       *dino,
+       xfs_ino_t               lino,
+       int                     *dirty)
+{
+       uint16_t                flags = be16_to_cpu(dino->di_flags);
+       unsigned int            value = be32_to_cpu(dino->di_extsize);
+       bool                    misaligned = false;
+       bool                    bad;
+
+       /*
+        * XFS allows a sysadmin to change the rt extent size when adding a rt
+        * section to a filesystem after formatting.  If there are any
+        * directories with extszinherit and rtinherit set, the hint could
+        * become misaligned with the new rextsize.  The verifier doesn't check
+        * this, because we allow rtinherit directories even without an rt
+        * device.
+        */
+       if ((flags & XFS_DIFLAG_EXTSZINHERIT) &&
+           (flags & XFS_DIFLAG_RTINHERIT) &&
+           value % mp->m_sb.sb_rextsize > 0)
+               misaligned = true;
+
+       /*
+        * Complain if the verifier fails.
+        *
+        * Old kernels didn't check the alignment of extsize hints when copying
+        * them to new regular realtime files.  The inode verifier now checks
+        * the alignment (because misaligned hints cause misbehavior in the rt
+        * allocator), so we have to complain and fix them.
+        */
+       bad = libxfs_inode_validate_extsize(mp, value,
+                       be16_to_cpu(dino->di_mode), flags) != NULL;
+       if (bad || misaligned) {
+               do_warn(
+_("Bad extent size hint %u on inode %" PRIu64 ", "),
+                               value, lino);
+               if (!no_modify)  {
+                       do_warn(_("resetting to zero\n"));
+                       dino->di_extsize = 0;
+                       dino->di_flags &= ~cpu_to_be16(XFS_DIFLAG_EXTSIZE |
+                                                      XFS_DIFLAG_EXTSZINHERIT);
+                       *dirty = 1;
+               } else
+                       do_warn(_("would reset to zero\n"));
+       }
+}
+
 /*
  * returns 0 if the inode is ok, 1 if the inode is corrupt
  * check_dups can be set to 1 *only* when called by the
@@ -2690,26 +2740,7 @@ _("bad (negative) size %" PRId64 " on inode %" PRIu64 "\n"),
        if (process_check_sb_inodes(mp, dino, lino, &type, dirty) != 0)
                goto clear_bad_out;
 
-       /*
-        * only regular files with REALTIME or EXTSIZE flags set can have
-        * extsize set, or directories with EXTSZINHERIT.
-        */
-       if (libxfs_inode_validate_extsize(mp,
-                       be32_to_cpu(dino->di_extsize),
-                       be16_to_cpu(dino->di_mode),
-                       be16_to_cpu(dino->di_flags)) != NULL) {
-               do_warn(
-_("Bad extent size %u on inode %" PRIu64 ", "),
-                               be32_to_cpu(dino->di_extsize), lino);
-               if (!no_modify)  {
-                       do_warn(_("resetting to zero\n"));
-                       dino->di_extsize = 0;
-                       dino->di_flags &= ~cpu_to_be16(XFS_DIFLAG_EXTSIZE |
-                                                      XFS_DIFLAG_EXTSZINHERIT);
-                       *dirty = 1;
-               } else
-                       do_warn(_("would reset to zero\n"));
-       }
+       validate_extsize(mp, dino, lino, dirty);
 
        /*
         * Only (regular files and directories) with COWEXTSIZE flags