Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Theodore Tso <tytso@mit.edu>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 37/92] ext4: prohibit fstrim in norecovery mode
Date:   Thu, 18 Apr 2019 19:56:55 +0200
Message-Id: <20190418160433.569902616@linuxfoundation.org>
In-Reply-To: <20190418160430.325165109@linuxfoundation.org>
References: <20190418160430.325165109@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

[ 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>
---
 fs/ext4/ioctl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7917cc89ab21..3dbf4e414706 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -940,6 +940,13 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		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;
-- 
2.19.1