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ublk: support device recovery without I/O queueing

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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 combination
UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_FAIL_IO.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241007182419.3263186-5-ushankar@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Uday Shankar 2024-10-07 12:24:17 -06:00 committed by Jens Axboe
parent 27b5d4170c
commit 59eaa01ce7
2 changed files with 81 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
drivers/block/ublk_drv.c
View File

@ -60,10 +60,12 @@
| UBLK_F_UNPRIVILEGED_DEV \
| UBLK_F_CMD_IOCTL_ENCODE \
| UBLK_F_USER_COPY \
| UBLK_F_ZONED)
| UBLK_F_ZONED \
| UBLK_F_USER_RECOVERY_FAIL_IO)
#define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \
| UBLK_F_USER_RECOVERY_REISSUE)
| UBLK_F_USER_RECOVERY_REISSUE \
| UBLK_F_USER_RECOVERY_FAIL_IO)
/* All UBLK_PARAM_TYPE_* should be included here */
#define UBLK_PARAM_TYPE_ALL \
@ -146,6 +148,7 @@ struct ublk_queue {
bool force_abort;
bool timeout;
bool canceling;
bool fail_io; /* copy of dev->state == UBLK_S_DEV_FAIL_IO */
unsigned short nr_io_ready; /* how many ios setup */
spinlock_t cancel_lock;
struct ublk_device *dev;
@ -690,7 +693,8 @@ static inline bool ublk_nosrv_should_reissue_outstanding(struct ublk_device *ub)
*/
static inline bool ublk_nosrv_dev_should_queue_io(struct ublk_device *ub)
{
return ub->dev_info.flags & UBLK_F_USER_RECOVERY;
return (ub->dev_info.flags & UBLK_F_USER_RECOVERY) &&
!(ub->dev_info.flags & UBLK_F_USER_RECOVERY_FAIL_IO);
}
/*
@ -700,7 +704,8 @@ static inline bool ublk_nosrv_dev_should_queue_io(struct ublk_device *ub)
*/
static inline bool ublk_nosrv_should_queue_io(struct ublk_queue *ubq)
{
return ubq->flags & UBLK_F_USER_RECOVERY;
return (ubq->flags & UBLK_F_USER_RECOVERY) &&
!(ubq->flags & UBLK_F_USER_RECOVERY_FAIL_IO);
}
/*
@ -714,6 +719,12 @@ static inline bool ublk_nosrv_should_stop_dev(struct ublk_device *ub)
return !(ub->dev_info.flags & UBLK_F_USER_RECOVERY);
}
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)
{
struct ublk_device *ub = disk->private_data;
@ -1275,6 +1286,10 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
struct request *rq = bd->rq;
blk_status_t res;
if (unlikely(ubq->fail_io)) {
return BLK_STS_TARGET;
}
/* fill iod to slot in io cmd buffer */
res = ublk_setup_iod(ubq, rq);
if (unlikely(res != BLK_STS_OK))
@ -1625,6 +1640,7 @@ static void ublk_nosrv_work(struct work_struct *work)
{
struct ublk_device *ub =
container_of(work, struct ublk_device, nosrv_work);
int i;
if (ublk_nosrv_should_stop_dev(ub)) {
ublk_stop_dev(ub);
@ -1634,7 +1650,18 @@ static void ublk_nosrv_work(struct work_struct *work)
mutex_lock(&ub->mutex);
if (ub->dev_info.state != UBLK_S_DEV_LIVE)
goto unlock;
if (ublk_nosrv_dev_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;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
ublk_get_queue(ub, i)->fail_io = true;
}
blk_mq_unquiesce_queue(ub->ub_disk->queue);
}
unlock:
mutex_unlock(&ub->mutex);
ublk_cancel_dev(ub);
@ -2387,8 +2414,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
return -EPERM;
/* forbid nonsense combinations of recovery flags */
if ((info.flags & UBLK_F_USER_RECOVERY_REISSUE) &&
!(info.flags & UBLK_F_USER_RECOVERY)) {
switch (info.flags & UBLK_F_ALL_RECOVERY_FLAGS) {
case 0:
case UBLK_F_USER_RECOVERY:
case (UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_REISSUE):
case (UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_FAIL_IO):
break;
default:
pr_warn("%s: invalid recovery flags %llx\n", __func__,
info.flags & UBLK_F_ALL_RECOVERY_FLAGS);
return -EINVAL;
@ -2729,14 +2761,18 @@ 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;
}
@ -2760,6 +2796,7 @@ static int ublk_ctrl_end_recovery(struct ublk_device *ub,
const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
int ublksrv_pid = (int)header->data[0];
int ret = -EINVAL;
int i;
pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
__func__, ub->dev_info.nr_hw_queues, header->dev_id);
@ -2774,18 +2811,29 @@ 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);
if (ublk_nosrv_dev_should_queue_io(ub)) {
ub->dev_info.state = UBLK_S_DEV_LIVE;
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);
} else {
blk_mq_quiesce_queue(ub->ub_disk->queue);
ub->dev_info.state = UBLK_S_DEV_LIVE;
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
ublk_get_queue(ub, i)->fail_io = false;
}
blk_mq_unquiesce_queue(ub->ub_disk->queue);
}
ret = 0;
out_unlock:
mutex_unlock(&ub->mutex);

18
include/uapi/linux/ublk_cmd.h
View File

@ -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)
/*
@ -190,10 +200,18 @@
*/
#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_FAIL_IO (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 {