ext4: prohibit fstrim in norecovery mode

The ext4 fstrim implementation uses the block bitmaps to find free space
that can be discarded.  If we haven't replayed the journal, the bitmaps
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>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index eb8ca8d80885ad917d9892a26c467dbae6a436e9..73435444b15934e11247264639505506312323ed 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1000,6 +1000,13 @@ resizefs_out:
                if (!blk_queue_discard(q))
                        return -EOPNOTSUPP;
 
+               /*
+                * We haven't replayed the journal, so we cannot use our
+                * block-bitmap-guided storage zapping commands.
+                */
+               if (test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb))
+                       return -EROFS;
+
                if (copy_from_user(&range, (struct fstrim_range __user *)arg,
                    sizeof(range)))
                        return -EFAULT;