From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Sat, 23 Mar 2019 16:10:29 +0000 (-0400)
Subject: ext4: prohibit fstrim in norecovery mode
X-Git-Tag: v4.14.113~56
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6fee657dfd593ad45c762fa2613c0c14406188ba;p=thirdparty%2Fkernel%2Fstable.git

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 7917cc89ab216..3dbf4e4147064 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -940,6 +940,13 @@ 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;