| Message ID | 20220922061734.21625-7-ZiyangZhang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ublk_drv: add USER_RECOVERY support | expand |
On 2022/9/22 14:17, ZiyangZhang wrote: > With recovery feature enabled, if ublk chardev is ready to be released > and quiesce_work has been scheduled, we: > (1) reinit all ubqs, including: > (a) put the task_struct and reset ->ubq_daemon to NULL. > (b) reset all ublk_io. > (2) reset ub->mm to NULL. > Then ublk chardev is released and new process can open it. > > RECOVER_DEV is introduced as a new ctrl-cmd for recovery feature. > After the chardev is opened and all ubqs are ready, user should send > RECOVER_DEV to: > (1) wait until all new ubq_daemons getting ready. > (2) update ublksrv_pid > (3) unquiesce the request queue and expect incoming ublk_queue_rq() > (4) convert ub's state to UBLK_S_DEV_LIVE > (5) reschedule monitor_work > > Signed-off-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> > --- > drivers/block/ublk_drv.c | 67 +++++++++++++++++++++++++++++++++++ > include/uapi/linux/ublk_cmd.h | 1 + > 2 files changed, 68 insertions(+) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 3977869d2bc4..ac8bf497567f 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -898,10 +898,40 @@ static int ublk_ch_open(struct inode *inode, struct file *filp) > return 0; > } > > +static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq) > +{ > + int i; > + > + /* old daemon is PF_EXITING, put it now */ > + if (ubq->ubq_daemon) { > + put_task_struct(ubq->ubq_daemon); > + /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */ > + ubq->ubq_daemon = NULL; > + } > + > + for (i = 0; i < ubq->q_depth; i++) { > + struct ublk_io *io = &ubq->ios[i]; > + > + /* forget everything now and be ready for new FETCH_REQ */ > + io->flags = 0; > + io->cmd = NULL; > + io->addr = 0; > + } > + ubq->nr_io_ready = 0; > +} > + > static int ublk_ch_release(struct inode *inode, struct file *filp) > { > struct ublk_device *ub = filp->private_data; > + int i; > > + pr_devel("%s: reinit queues for dev id %d.\n", __func__, ub->dev_info.dev_id); > + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) > + ublk_queue_reinit(ub, ublk_get_queue(ub, i)); > + /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */ > + ub->mm = NULL; > + ub->nr_queues_ready = 0; > + init_completion(&ub->completion); > clear_bit(UB_STATE_OPEN, &ub->state); > return 0; > } This one is not correct. I will figure out how to correctly put_task_struct(ubq->ubq_daemon) with recovery feature enabled.
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 3977869d2bc4..ac8bf497567f 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -898,10 +898,40 @@ static int ublk_ch_open(struct inode *inode, struct file *filp) return 0; } +static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq) +{ + int i; + + /* old daemon is PF_EXITING, put it now */ + if (ubq->ubq_daemon) { + put_task_struct(ubq->ubq_daemon); + /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */ + ubq->ubq_daemon = NULL; + } + + for (i = 0; i < ubq->q_depth; i++) { + struct ublk_io *io = &ubq->ios[i]; + + /* forget everything now and be ready for new FETCH_REQ */ + io->flags = 0; + io->cmd = NULL; + io->addr = 0; + } + ubq->nr_io_ready = 0; +} + static int ublk_ch_release(struct inode *inode, struct file *filp) { struct ublk_device *ub = filp->private_data; + int i; + pr_devel("%s: reinit queues for dev id %d.\n", __func__, ub->dev_info.dev_id); + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) + ublk_queue_reinit(ub, ublk_get_queue(ub, i)); + /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */ + ub->mm = NULL; + ub->nr_queues_ready = 0; + init_completion(&ub->completion); clear_bit(UB_STATE_OPEN, &ub->state); return 0; } @@ -1873,6 +1903,40 @@ static int ublk_ctrl_set_params(struct io_uring_cmd *cmd) return ret; } +static int ublk_ctrl_recover_dev(struct io_uring_cmd *cmd) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + int ublksrv_pid = (int)header->data[0]; + struct ublk_device *ub; + int ret = -EINVAL; + + ub = ublk_get_device_from_id(header->dev_id); + if (!ub) + return ret; + + /* wait until new ubq_daemon sending all FETCH_REQ */ + wait_for_completion_interruptible(&ub->completion); + + mutex_lock(&ub->mutex); + if (!ublk_can_use_recovery(ub)) + goto out_unlock; + + if (ub->dev_info.state != UBLK_S_DEV_QUIESCED) { + ret = -EBUSY; + goto out_unlock; + } + ub->dev_info.ublksrv_pid = ublksrv_pid; + blk_mq_unquiesce_queue(ub->ub_disk->queue); + blk_mq_kick_requeue_list(ub->ub_disk->queue); + ub->dev_info.state = UBLK_S_DEV_LIVE; + schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD); + ret = 0; + out_unlock: + mutex_unlock(&ub->mutex); + ublk_put_device(ub); + return ret; +} + static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) { @@ -1914,6 +1978,9 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, case UBLK_CMD_SET_PARAMS: ret = ublk_ctrl_set_params(cmd); break; + case UBLK_CMD_RECOVER_DEV: + ret = ublk_ctrl_recover_dev(cmd); + break; default: break; } diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index 332370628757..deb674f1fbc9 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -17,6 +17,7 @@ #define UBLK_CMD_STOP_DEV 0x07 #define UBLK_CMD_SET_PARAMS 0x08 #define UBLK_CMD_GET_PARAMS 0x09 +#define UBLK_CMD_RECOVER_DEV 0x10 /* * IO commands, issued by ublk server, and handled by ublk driver.
With recovery feature enabled, if ublk chardev is ready to be released and quiesce_work has been scheduled, we: (1) reinit all ubqs, including: (a) put the task_struct and reset ->ubq_daemon to NULL. (b) reset all ublk_io. (2) reset ub->mm to NULL. Then ublk chardev is released and new process can open it. RECOVER_DEV is introduced as a new ctrl-cmd for recovery feature. After the chardev is opened and all ubqs are ready, user should send RECOVER_DEV to: (1) wait until all new ubq_daemons getting ready. (2) update ublksrv_pid (3) unquiesce the request queue and expect incoming ublk_queue_rq() (4) convert ub's state to UBLK_S_DEV_LIVE (5) reschedule monitor_work Signed-off-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> --- drivers/block/ublk_drv.c | 67 +++++++++++++++++++++++++++++++++++ include/uapi/linux/ublk_cmd.h | 1 + 2 files changed, 68 insertions(+)