xfs: fix bad_features2 fixups for the root filesystem

Currently the bad_features2 fixup and the alignment updates in the superblock
are skipped if we mount a filesystem read-only.  But for the root filesystem
the typical case is to mount read-only first and only later remount writeable
so we'll never perform this update at all.  It's not a big problem but means
the logs of people needing the fixup get spammed at every boot because they
never happen on disk.

Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 95a97108036..c71e226da7f 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1197,6 +1197,7 @@ xfs_fs_remount(
         struct xfs_mount        *mp = XFS_M(sb);
         substring_t             args[MAX_OPT_ARGS];
         char                    *p;
+        int                     error;
 
         while ((p = strsep(&options, ",")) != NULL) {
                 int token;
@@ -1247,11 +1248,25 @@ xfs_fs_remount(
                 }
         }
 
-        /* rw/ro -> rw */
+        /* ro -> rw */
         if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & MS_RDONLY)) {
                 mp->m_flags &= ~XFS_MOUNT_RDONLY;
                 if (mp->m_flags & XFS_MOUNT_BARRIER)
                         xfs_mountfs_check_barriers(mp);
+
+                /*
+                 * If this is the first remount to writeable state we
+                 * might have some superblock changes to update.
+                 */
+                if (mp->m_update_flags) {
+                        error = xfs_mount_log_sb(mp, mp->m_update_flags);
+                        if (error) {
+                                cmn_err(CE_WARN,
+                                        "XFS: failed to write sb changes");
+                                return error;
+                        }
+                        mp->m_update_flags = 0;
+                }
         }
 
         /* rw -> ro */