xfs: disable noattr2/attr2 mount options for CRC enabled filesystems

attr2 format is always enabled for v5 superblock filesystems, so the
mount options to enable or disable it need to be cause mount errors.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit d3eaace84e40bf946129e516dcbd617173c1cf14)

2 files changed, 14 insertions, 0 deletions

diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
index 3e4b3dd1e046..83577f0232a0 100644
--- a/Documentation/filesystems/xfs.txt
+++ b/Documentation/filesystems/xfs.txt
@@ -33,6 +33,9 @@ When mounting an XFS filesystem, the following options are accepted.
         removing extended attributes) the on-disk superblock feature
         bit field will be updated to reflect this format being in use.
 
+        CRC enabled filesystems always use the attr2 format, and so
+        will reject the noattr2 mount option if it is set.
+
   barrier
         Enables the use of block layer write barriers for writes into
         the journal and unwritten extent conversion.  This allows for
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index ea341cea68cb..3033ba5e9762 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1373,6 +1373,17 @@ xfs_finish_flags(
         }
 
         /*
+         * V5 filesystems always use attr2 format for attributes.
+         */
+        if (xfs_sb_version_hascrc(&mp->m_sb) &&
+            (mp->m_flags & XFS_MOUNT_NOATTR2)) {
+                xfs_warn(mp,
+"Cannot mount a V5 filesystem as %s. %s is always enabled for V5 filesystems.",
+                        MNTOPT_NOATTR2, MNTOPT_ATTR2);
+                return XFS_ERROR(EINVAL);
+        }
+
+        /*
          * mkfs'ed attr2 will turn on attr2 mount unless explicitly
          * told by noattr2 to turn it off
          */