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md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_set

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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).

Shaohua: fix unlock in failure cases

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
Song Liu 2017-07-31 14:52:26 -07:00 committed by Shaohua Li
parent 81fe48e9aa
commit b44886c54a
1 changed files with 15 additions and 6 deletions
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21
drivers/md/raid5-cache.c
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@ -2540,23 +2540,32 @@ 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) {
mddev_unlock(mddev);
return -ENODEV;
}
if (raid5_calc_degraded(conf) > 0 &&
mode == R5C_JOURNAL_MODE_WRITE_BACK)
mode == R5C_JOURNAL_MODE_WRITE_BACK) {
mddev_unlock(mddev);
return -EINVAL;
}
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]);