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@xxxxxxxxxxxxxxx> --- Changes since v1 (https://lore.kernel.org/linux-block/20240617194451.435445-5-ushankar@xxxxxxxxxxxxxxx/): - Change flag name from UBLK_F_USER_RECOVERY_NOQUEUE to UBLK_F_USER_RECOVERY_FAIL_IO - Require UBLK_F_USER_RECOVERY to be set along with the new flag for it to be effective. This makes more sense, as UBLK_F_USER_RECOVERY essentially selects behavior 2 above (and not setting UBLK_F_USER_RECOVERY selects behavior 1). - Add per-ublk-queue flag which is true iff device state is UBLK_S_DEV_FAIL_IO. This lets us avoid fetching the device in the fast path. drivers/block/ublk_drv.c | 75 ++++++++++++++++++++++++++++------- include/uapi/linux/ublk_cmd.h | 18 +++++++++ 2 files changed, 79 insertions(+), 14 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index c7a0493b3545..548043eeefb9 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -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); } /* @@ -712,7 +717,14 @@ static inline bool ublk_nosrv_should_queue_io(struct ublk_queue *ubq) 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_FAIL_IO)); +} + +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) @@ -1276,6 +1288,10 @@ 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)) @@ -1626,6 +1642,7 @@ 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); @@ -1635,7 +1652,18 @@ static void ublk_nosrv_work(struct work_struct *work) mutex_lock(&ub->mutex); if (ub->dev_info.state != UBLK_S_DEV_LIVE) goto unlock; - __ublk_quiesce_dev(ub); + + if (ublk_nosrv_dev_should_queue_io(ub)) { + __ublk_quiesce_dev(ub); + } else { + blk_mq_quiesce_queue(ub->ub_disk->queue); + 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); + ub->dev_info.state = UBLK_S_DEV_FAIL_IO; + } + unlock: mutex_unlock(&ub->mutex); ublk_cancel_dev(ub); @@ -2389,8 +2417,13 @@ 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; @@ -2722,14 +2755,18 @@ 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; } @@ -2753,6 +2790,7 @@ 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); @@ -2767,18 +2805,27 @@ 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_quiesce_queue(ub->ub_disk->queue); + 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); - 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_dev_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..a2b3ea344639 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_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 { -- 2.34.1
