[PATCH 5.18 0815/1095] block/rnbd-srv: Set keep_id to true after mutex_trylock

Greg Kroah-Hartman
2022-08-15T22:28:20Z

From: Md Haris Iqbal <haris.iqbal@ionos.com>

[ Upstream commit 4bc14f3101364877dd59085f39e068a2a7ec9f2d ]

After setting keep_id if the mutex trylock fails, the keep_id stays set
for the rest of the sess_dev lifetime.

Therefore, set keep_id to true after mutex_trylock succeeds, so that a
failure of trylock does'nt touch keep_id.

Fixes: b168e1d85cf3 ("block/rnbd-srv: Prevent a deadlock generated by accessing sysfs in parallel")
Cc: gi-oh.kim@ionos.com
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20220707143122.460362-2-haris.iqbal@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/rnbd/rnbd-srv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index f04df6294650..963df70ea026 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -323,10 +323,11 @@ void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
{
struct rnbd_srv_session *sess = sess_dev->sess;

- sess_dev->keep_id = true;
/* It is already started to close by client's close message. */
if (!mutex_trylock(&sess->lock))
return;
+
+ sess_dev->keep_id = true;
/* first remove sysfs itself to avoid deadlock */
sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
rnbd_srv_destroy_dev_session_sysfs(sess_dev);
--
2.35.1