diff options
author | Dongsheng Yang <dongsheng.yang@easystack.cn> | 2020-12-07 19:39:15 +0300 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2020-12-07 23:25:16 +0300 |
commit | df4ad53242158f9f1f97daf4feddbb4f8b77f080 (patch) | |
tree | 254fd64b672dcea3498c8ddc46e61fa57d8e0a78 /drivers/md/bcache/super.c | |
parent | 733c15bd3a944b8eeaacdddf061759b6a83dd3f4 (diff) | |
download | linux-df4ad53242158f9f1f97daf4feddbb4f8b77f080.tar.xz |
bcache: fix race between setting bdev state to none and new write request direct to backing
There is a race condition in detaching as below:
A. detaching B. Write request
(1) writing back
(2) write back done, set bdev
state to clean.
(3) cached_dev_put() and
schedule_work(&dc->detach);
(4) write data [0 - 4K] directly
into backing and ack to user.
(5) power-failure...
When we restart this bcache device, this bdev is clean but not detached,
and read [0 - 4K], we will get unexpected old data from cache device.
To fix this problem, set the bdev state to none when we writeback done
in detaching, and then if power-failure happened as above, the data in
cache will not be used in next bcache device starting, it's detached, we
will read the correct data from backing derectly.
Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache/super.c')
-rw-r--r-- | drivers/md/bcache/super.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 46a00134a36a..b1a6ba9a5adb 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1114,9 +1114,6 @@ static void cancel_writeback_rate_update_dwork(struct cached_dev *dc) static void cached_dev_detach_finish(struct work_struct *w) { struct cached_dev *dc = container_of(w, struct cached_dev, detach); - struct closure cl; - - closure_init_stack(&cl); BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)); BUG_ON(refcount_read(&dc->count)); @@ -1130,12 +1127,6 @@ static void cached_dev_detach_finish(struct work_struct *w) dc->writeback_thread = NULL; } - memset(&dc->sb.set_uuid, 0, 16); - SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE); - - bch_write_bdev_super(dc, &cl); - closure_sync(&cl); - mutex_lock(&bch_register_lock); calc_cached_dev_sectors(dc->disk.c); |