ext4: Block writes to journal device

Ask block layer to not allow other writers to open block device used
for ext4 journal.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231101174325.10596-7-jack@suse.cz
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index bd752f3f1dd526d9935f9d5796f0f617c03213d8..0980845c8b8f103acc906e21d0f2c9a9f2f64ab6 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5864,8 +5864,9 @@ static struct bdev_handle *ext4_get_journal_blkdev(struct super_block *sb,
        struct ext4_super_block *es;
        int errno;
 
-       bdev_handle = bdev_open_by_dev(j_dev, BLK_OPEN_READ | BLK_OPEN_WRITE,
-                                      sb, &fs_holder_ops);
+       bdev_handle = bdev_open_by_dev(j_dev,
+               BLK_OPEN_READ | BLK_OPEN_WRITE | BLK_OPEN_RESTRICT_WRITES,
+               sb, &fs_holder_ops);
        if (IS_ERR(bdev_handle)) {
                ext4_msg(sb, KERN_ERR,
                         "failed to open journal device unknown-block(%u,%u) %ld",