xfs: prohibit fstrim in norecovery mode

The xfs fstrim implementation uses the free space btrees to find free
space that can be discarded.  If we haven't recovered the log, the bnobt
will be stale and we absolutely *cannot* use stale metadata to zap the
underlying storage.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index 93f07ed..9ee2a7d 100644 (file)
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -161,6 +161,14 @@ xfs_ioc_trim(
                return -EPERM;
        if (!blk_queue_discard(q))
                return -EOPNOTSUPP;
+
+       /*
+        * We haven't recovered the log, so we cannot use our bnobt-guided
+        * storage zapping commands.
+        */
+       if (mp->m_flags & XFS_MOUNT_NORECOVERY)
+               return -EROFS;
+
        if (copy_from_user(&range, urange, sizeof(range)))
                return -EFAULT;