ublk currently supports the following behaviors on ublk server exit:
A: outstanding I/Os get errors, subsequently issued I/Os get errors
B: outstanding I/Os get errors, subsequently issued I/Os queue
C: outstanding I/Os get reissued, subsequently issued I/Os queue
and the following behaviors for recovery of preexisting block devices by
a future incarnation of the ublk server:
1: ublk devices stopped on ublk server exit (no recovery possible)
2: ublk devices are recoverable using start/end_recovery commands
The userspace interface allows selection of combinations of these
behaviors using flags specified at device creation time, namely:
default behavior: A + 1
UBLK_F_USER_RECOVERY: B + 2
UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_REISSUE: C + 2
The behavior A + 2 is currently unsupported. Add support for this
behavior under the new flag UBLK_F_USER_RECOVERY_NOQUEUE.
Signed-off-by: Uday Shankar <ushankar@xxxxxxxxxxxxxxx>
---
drivers/block/ublk_drv.c | 53 +++++++++++++++++++++++++++--------
include/uapi/linux/ublk_cmd.h | 18 ++++++++++++
2 files changed, 60 insertions(+), 11 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 0496fa372cc1..4fec8b48d30e 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -57,10 +57,12 @@
| UBLK_F_UNPRIVILEGED_DEV \
| UBLK_F_CMD_IOCTL_ENCODE \
| UBLK_F_USER_COPY \
- | UBLK_F_ZONED)
+ | UBLK_F_ZONED \
+ | UBLK_F_USER_RECOVERY_NOQUEUE)
#define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \
- | UBLK_F_USER_RECOVERY_REISSUE)
+ | UBLK_F_USER_RECOVERY_REISSUE \
+ | UBLK_F_USER_RECOVERY_NOQUEUE)
/* All UBLK_PARAM_TYPE_* should be included here */
#define UBLK_PARAM_TYPE_ALL \
@@ -679,7 +681,14 @@ static inline bool ublk_nosrv_should_queue_io(struct ublk_device *ub)
static inline bool ublk_nosrv_should_stop_dev(struct ublk_device *ub)
{
return (!(ub->dev_info.flags & UBLK_F_USER_RECOVERY)) &&
- (!(ub->dev_info.flags & UBLK_F_USER_RECOVERY_REISSUE));
+ (!(ub->dev_info.flags & UBLK_F_USER_RECOVERY_REISSUE)) &&
+ (!(ub->dev_info.flags & UBLK_F_USER_RECOVERY_NOQUEUE));
+}
+
+static inline bool ublk_dev_in_recoverable_state(struct ublk_device *ub)
+{
+ return ub->dev_info.state == UBLK_S_DEV_QUIESCED ||
+ ub->dev_info.state == UBLK_S_DEV_FAIL_IO;
}
static void ublk_free_disk(struct gendisk *disk)
@@ -1243,6 +1252,11 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
struct request *rq = bd->rq;
blk_status_t res;
+ if (ubq->dev->dev_info.state == UBLK_S_DEV_FAIL_IO) {
+ return BLK_STS_TARGET;
+ }
+ WARN_ON_ONCE(ubq->dev->dev_info.state != UBLK_S_DEV_LIVE);
+
/* fill iod to slot in io cmd buffer */
res = ublk_setup_iod(ubq, rq);
if (unlikely(res != BLK_STS_OK))
@@ -1602,7 +1616,15 @@ static void ublk_nosrv_work(struct work_struct *work)
mutex_lock(&ub->mutex);
if (ub->dev_info.state != UBLK_S_DEV_LIVE)
goto unlock;
- __ublk_quiesce_dev(ub);
+
+ if (ublk_nosrv_should_queue_io(ub)) {
+ __ublk_quiesce_dev(ub);
+ } else {
+ blk_mq_quiesce_queue(ub->ub_disk->queue);
+ ub->dev_info.state = UBLK_S_DEV_FAIL_IO;
+ blk_mq_unquiesce_queue(ub->ub_disk->queue);
+ }
+
unlock:
mutex_unlock(&ub->mutex);
ublk_cancel_dev(ub);
@@ -2351,6 +2373,7 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
case 0:
case UBLK_F_USER_RECOVERY:
case (UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_REISSUE):
+ case UBLK_F_USER_RECOVERY_NOQUEUE:
break;
default:
pr_warn("%s: invalid recovery flags %llx\n", __func__,
@@ -2682,14 +2705,18 @@ static int ublk_ctrl_start_recovery(struct ublk_device *ub,
* and related io_uring ctx is freed so file struct of /dev/ublkcX is
* released.
*
+ * and one of the following holds
+ *
* (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
* (a)has quiesced request queue
* (b)has requeued every inflight rqs whose io_flags is ACTIVE
* (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
* (d)has completed/camceled all ioucmds owned by ther dying process
+ *
+ * (3) UBLK_S_DEV_FAIL_IO is set, which means the queue is not
+ * quiesced, but all I/O is being immediately errored
*/
- if (test_bit(UB_STATE_OPEN, &ub->state) ||
- ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
+ if (test_bit(UB_STATE_OPEN, &ub->state) || !ublk_dev_in_recoverable_state(ub)) {
ret = -EBUSY;
goto out_unlock;
}
@@ -2727,18 +2754,22 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub,
if (ublk_nosrv_should_stop_dev(ub))
goto out_unlock;
- if (ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
+ if (!ublk_dev_in_recoverable_state(ub)) {
ret = -EBUSY;
goto out_unlock;
}
ub->dev_info.ublksrv_pid = ublksrv_pid;
pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
__func__, ublksrv_pid, header->dev_id);
- blk_mq_unquiesce_queue(ub->ub_disk->queue);
- pr_devel("%s: queue unquiesced, dev id %d.\n",
- __func__, header->dev_id);
- blk_mq_kick_requeue_list(ub->ub_disk->queue);
+
ub->dev_info.state = UBLK_S_DEV_LIVE;
+ if (ublk_nosrv_should_queue_io(ub)) {
+ blk_mq_unquiesce_queue(ub->ub_disk->queue);
+ pr_devel("%s: queue unquiesced, dev id %d.\n",
+ __func__, header->dev_id);
+ blk_mq_kick_requeue_list(ub->ub_disk->queue);
+ }
+
ret = 0;
out_unlock:
mutex_unlock(&ub->mutex);
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index c8dc5f8ea699..c4512b3a3c52 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -147,8 +147,18 @@
*/
#define UBLK_F_NEED_GET_DATA (1UL << 2)
+/*
+ * - Block devices are recoverable if ublk server exits and restarts
+ * - Outstanding I/O when ublk server exits is met with errors
+ * - I/O issued while there is no ublk server queues
+ */
#define UBLK_F_USER_RECOVERY (1UL << 3)
+/*
+ * - Block devices are recoverable if ublk server exits and restarts
+ * - Outstanding I/O when ublk server exits is reissued
+ * - I/O issued while there is no ublk server queues
+ */
#define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
/*
@@ -184,10 +194,18 @@
*/
#define UBLK_F_ZONED (1ULL << 8)
+/*
+ * - Block devices are recoverable if ublk server exits and restarts
+ * - Outstanding I/O when ublk server exits is met with errors
+ * - I/O issued while there is no ublk server is met with errors
+ */
+#define UBLK_F_USER_RECOVERY_NOQUEUE (1ULL << 9)
+
/* device state */
#define UBLK_S_DEV_DEAD 0
#define UBLK_S_DEV_LIVE 1
#define UBLK_S_DEV_QUIESCED 2
+#define UBLK_S_DEV_FAIL_IO 3
/* shipped via sqe->cmd of io_uring command */
struct ublksrv_ctrl_cmd {
--
2.34.1
