| Message ID | 20190805004336.16181-1-lizhongfs@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7d8948627a7cd84c45069276e5fcddf6ab074baa |
| Headers | show |
| Series | [RFC,v2] target: tcmu: clean the nl_cmd of the udev when nl send fails | expand |
On 08/04/2019 07:43 PM, Li Zhong wrote: > If the userspace process crashes while we send the nl msg, it is possible > that the cmd in curr_nl_cmd of tcmu_dev never gets reset to 0, and > and returns busy for other commands after the userspace process is > restartd. > > More details below: > > /backstores/user:file/file> set attribute dev_size=2048 > Cannot set attribute dev_size: [Errno 3] No such process > /backstores/user:file/file> set attribute dev_size=2048 > Cannot set attribute dev_size: [Errno 16] Device or resource busy > > with following kernel messages: > [173605.747169] Unable to reconfigure device > [173616.686674] tcmu daemon: command reply support 1. > [173623.866978] netlink cmd 3 already executing on file > [173623.866984] Unable to reconfigure device > > Also, it is not safe to leave the nl_cmd in the list, and not get > deleted. > > This patch removes the nl_cmd from the list, and clear its data if > it is not sent successfully. > > Signed-off-by: Li Zhong <lizhongfs@gmail.com> Acked-by: Mike Christie <mchristi@redhat.com>
Li, > If the userspace process crashes while we send the nl msg, it is > possible that the cmd in curr_nl_cmd of tcmu_dev never gets reset to > 0, and and returns busy for other commands after the userspace process > is restartd. Applied to 5.4/scsi-queue, thanks!
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 04eda111920e..68045cbca595 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1708,6 +1708,24 @@ static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd) return 0; } +static void tcmu_destroy_genl_cmd_reply(struct tcmu_dev *udev) +{ + struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd; + + if (!tcmu_kern_cmd_reply_supported) + return; + + if (udev->nl_reply_supported <= 0) + return; + + mutex_lock(&tcmu_nl_cmd_mutex); + + list_del(&nl_cmd->nl_list); + memset(nl_cmd, 0, sizeof(*nl_cmd)); + + mutex_unlock(&tcmu_nl_cmd_mutex); +} + static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev) { struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd; @@ -1788,6 +1806,8 @@ static int tcmu_netlink_event_send(struct tcmu_dev *udev, if (ret == 0 || (ret == -ESRCH && cmd == TCMU_CMD_ADDED_DEVICE)) return tcmu_wait_genl_cmd_reply(udev); + else + tcmu_destroy_genl_cmd_reply(udev); return ret; }
If the userspace process crashes while we send the nl msg, it is possible that the cmd in curr_nl_cmd of tcmu_dev never gets reset to 0, and and returns busy for other commands after the userspace process is restartd. More details below: /backstores/user:file/file> set attribute dev_size=2048 Cannot set attribute dev_size: [Errno 3] No such process /backstores/user:file/file> set attribute dev_size=2048 Cannot set attribute dev_size: [Errno 16] Device or resource busy with following kernel messages: [173605.747169] Unable to reconfigure device [173616.686674] tcmu daemon: command reply support 1. [173623.866978] netlink cmd 3 already executing on file [173623.866984] Unable to reconfigure device Also, it is not safe to leave the nl_cmd in the list, and not get deleted. This patch removes the nl_cmd from the list, and clear its data if it is not sent successfully. Signed-off-by: Li Zhong <lizhongfs@gmail.com> --- drivers/target/target_core_user.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)