In r5c_journal_mode_set(), 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: Song Liu <songliubraving@xxxxxx>
---
drivers/md/raid5-cache.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index bfa1e90..98b5aa9 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -2540,16 +2540,20 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
*/
int r5c_journal_mode_set(struct mddev *mddev, int mode)
{
- struct r5conf *conf = mddev->private;
- struct r5l_log *log = conf->log;
-
- if (!log)
- return -ENODEV;
+ struct r5conf *conf;
+ int err;
if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
mode > R5C_JOURNAL_MODE_WRITE_BACK)
return -EINVAL;
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+ conf = mddev->private;
+ if (!conf || !conf->log)
+ return -ENODEV;
+
if (raid5_calc_degraded(conf) > 0 &&
mode == R5C_JOURNAL_MODE_WRITE_BACK)
return -EINVAL;
@@ -2557,6 +2561,7 @@ int r5c_journal_mode_set(struct mddev *mddev, int mode)
mddev_suspend(mddev);
conf->log->r5c_journal_mode = mode;
mddev_resume(mddev);
+ mddev_unlock(mddev);
pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
mdname(mddev), mode, r5c_journal_mode_str[mode]);
--
2.9.3
--
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