ext4: prohibit fstrim in norecovery mode

[ Upstream commit 18915b5873f07e5030e6fb108a050fa7c71c59fb ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 2e76fb55d94ac90fae96fc0b2e3639f88e8fb68a..5f24fdc140add9db04c5a32da57bac796e9c562a 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -999,6 +999,13 @@ 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;