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Commit a72cbf83 authored by Song Liu's avatar Song Liu Committed by Shaohua Li
Browse files

md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show 



In r5c_journal_mode_show(), it is necessary to call mddev_lock()
before accessing conf and conf->log. Otherwise, the conf->log
may change (and become NULL).

Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 26e13043

drivers/md/raid5-cache.c

+10 −2
Original line number Diff line number Diff line
@@ -2529,11 +2529,18 @@ static void r5l_write_super(struct r5l_log *log, sector_t cp) 


static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)

{

	struct r5conf *conf = mddev->private;

	struct r5conf *conf;

	int ret;



	if (!conf->log)

	ret = mddev_lock(mddev);

	if (ret)

		return ret;



	conf = mddev->private;

	if (!conf || !conf->log) {

		mddev_unlock(mddev);

		return 0;

	}



	switch (conf->log->r5c_journal_mode) {

	case R5C_JOURNAL_MODE_WRITE_THROUGH:
@@ -2551,6 +2558,7 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page) 
	default:

		ret = 0;

	}

	mddev_unlock(mddev);

	return ret;

}