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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
Download Patch File Download Diff File Expand all files Collapse all files
include/uapi/linux/ublk_cmd.h
+18
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 {