ext4: Block writes to journal device

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MPXP
Reference: https://lore.kernel.org/all/20231101174325.10596-7-jack@suse.cz/



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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>

Conflicts:
  fs/ext4/super.c
  commit 218de67764e5 ("ext4: simplify device handling") in linux-next
  removed use of s_umount
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>