bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached
When people set a writeback percent via sysfs file, /sys/block/bcache<N>/bcache/writeback_percent current code directly sets BCACHE_DEV_WB_RUNNING to dc->disk.flags and schedules kworker dc->writeback_rate_update. If there is no cache set attached to, the writeback kernel thread is not running indeed, running dc->writeback_rate_update does not make sense and may cause NULL pointer deference when reference cache set pointer inside update_writeback_rate(). This patch checks whether the cache set point (dc->disk.c) is NULL in sysfs interface handler, and only set BCACHE_DEV_WB_RUNNING and schedule dc->writeback_rate_update when dc->disk.c is not NULL (it means the cache device is attached to a cache set). This problem might be introduced from initial bcache commit, but commit3fd47bfe55
("bcache: stop dc->writeback_rate_update properly") changes part of the original code piece, so I add 'Fixes: 3fd47bfe55b0' to indicate from which commit this patch can be applied. Fixes:3fd47bfe55
("bcache: stop dc->writeback_rate_update properly") Reported-by: Bjørn Forsman <bjorn.forsman@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Bjørn Forsman <bjorn.forsman@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
31b90956b1
commit
1f0ffa6734
|
@ -431,8 +431,13 @@ STORE(bch_cached_dev)
|
|||
bch_writeback_queue(dc);
|
||||
}
|
||||
|
||||
/*
|
||||
* Only set BCACHE_DEV_WB_RUNNING when cached device attached to
|
||||
* a cache set, otherwise it doesn't make sense.
|
||||
*/
|
||||
if (attr == &sysfs_writeback_percent)
|
||||
if (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
|
||||
if ((dc->disk.c != NULL) &&
|
||||
(!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)))
|
||||
schedule_delayed_work(&dc->writeback_rate_update,
|
||||
dc->writeback_rate_update_seconds * HZ);
|
||||
|
||||
|
|
Loading…
Reference in a new issue