UBLK_F_USER_RECOVERY_REISSUE implies that:
With a dying ubq_daemon, ublk_drv let monitor_work requeues rq issued to
userspace(ublksrv) before the ubq_daemon is dying.
UBLK_F_USER_RECOVERY_REISSUE is designed for backends which:
(1) tolerate double-write since ublk_drv may issue the same rq
twice.
(2) does not let frontend users get I/O error, such as read-only FS
and VM backend.
Signed-off-by: ZiyangZhang <ZiyangZhang@xxxxxxxxxxxxxxxxx>
---
drivers/block/ublk_drv.c | 17 +++++++++++++++--
include/uapi/linux/ublk_cmd.h | 2 ++
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 9610afe11463..dc33ebc20c01 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -50,7 +50,8 @@
#define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
| UBLK_F_URING_CMD_COMP_IN_TASK \
| UBLK_F_NEED_GET_DATA \
- | UBLK_F_USER_RECOVERY)
+ | UBLK_F_USER_RECOVERY \
+ | UBLK_F_USER_RECOVERY_REISSUE)
/* All UBLK_PARAM_TYPE_* should be included here */
#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD)
@@ -325,6 +326,15 @@ static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)
PAGE_SIZE);
}
+static inline bool ublk_queue_can_use_recovery_reissue(
+ struct ublk_queue *ubq)
+{
+ if ((ubq->flags & UBLK_F_USER_RECOVERY) &&
+ (ubq->flags & UBLK_F_USER_RECOVERY_REISSUE))
+ return true;
+ return false;
+}
+
static inline bool ublk_queue_can_use_recovery(
struct ublk_queue *ubq)
{
@@ -641,7 +651,10 @@ static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io,
req->tag,
io->flags);
io->flags |= UBLK_IO_FLAG_ABORTED;
- blk_mq_end_request(req, BLK_STS_IOERR);
+ if (ublk_queue_can_use_recovery_reissue(ubq))
+ blk_mq_requeue_request(req, false);
+ else
+ blk_mq_end_request(req, BLK_STS_IOERR);
}
}
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 340ff14bde49..332370628757 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -76,6 +76,8 @@
#define UBLK_F_USER_RECOVERY (1UL << 3)
+#define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
+
/* device state */
#define UBLK_S_DEV_DEAD 0
#define UBLK_S_DEV_LIVE 1
--
2.27.0
