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master-next

Last commit made on 2022-06-23

Get this branch:: git clone -b master-next https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-azure/+git/impish

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Branch merges

Branch information

Name:: master-next

Repository:: lp:~canonical-kernel/ubuntu/+source/linux-azure/+git/impish

Recent commits

805d801... by Yu Kuai <email address hidden> on 2022-06-22

nbd: fix io hung while disconnecting device

BugLink: https://bugs.launchpad.net/bugs/1896350

In our tests, "qemu-nbd" triggers a io hung:

INFO: task qemu-nbd:11445 blocked for more than 368 seconds.
Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:qemu-nbd state:D stack: 0 pid:11445 ppid: 1 flags:0x00000000
Call Trace:
<TASK>
__schedule+0x480/0x1050
? _raw_spin_lock_irqsave+0x3e/0xb0
schedule+0x9c/0x1b0
blk_mq_freeze_queue_wait+0x9d/0xf0
? ipi_rseq+0x70/0x70
blk_mq_freeze_queue+0x2b/0x40
nbd_add_socket+0x6b/0x270 [nbd]
nbd_ioctl+0x383/0x510 [nbd]
blkdev_ioctl+0x18e/0x3e0
__x64_sys_ioctl+0xac/0x120
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd8ff706577
RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577
RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f
RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0
R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d
R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0

"qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following
message was found:

block nbd0: Send disconnect failed -32

Which indicate that something is wrong with the server. Then,
"qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear
requests after commit 2516ab1543fd("nbd: only clear the queue on device
teardown"). And in the meantime, request can't complete through timeout
because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which
means such request will never be completed in this situation.

Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't
complete multiple times, switch back to call nbd_clear_sock() in
nbd_clear_sock_ioctl(), so that inflight requests can be cleared.

Signed-off-by: Yu Kuai <email address hidden>
Reviewed-by: Josef Bacik <email address hidden>
Link: https://<email address hidden>
Signed-off-by: Jens Axboe <email address hidden>
(cherry picked from commit 09dadb5985023e27d4740ebd17e6fea4640110e5)
Signed-off-by: Matthew Ruffell <email address hidden>
Acked-by: Tim Gardner <email address hidden>
Acked-by: Bartlomiej Zolnierkiewicz <email address hidden>
Signed-off-by: Tim Gardner <email address hidden>

2541df1... by Yu Kuai <email address hidden> on 2022-06-22

nbd: don't clear 'NBD_CMD_INFLIGHT' flag if request is not completed

BugLink: https://bugs.launchpad.net/bugs/1896350

Otherwise io will hung because request will only be completed if the
cmd has the flag 'NBD_CMD_INFLIGHT'.

Fixes: 07175cb1baf4 ("nbd: make sure request completion won't concurrent")
Signed-off-by: Yu Kuai <email address hidden>
Link: https://<email address hidden>
Signed-off-by: Jens Axboe <email address hidden>
(backported from 2895f1831e911ca87d4efdf43e35eb72a0c7e66e)
[mruffell: context adjustment removing percpu_ref_put in recv_work()]
Signed-off-by: Matthew Ruffell <email address hidden>
Acked-by: Tim Gardner <email address hidden>
Acked-by: Bartlomiej Zolnierkiewicz <email address hidden>
Signed-off-by: Tim Gardner <email address hidden>

db36fa7... by Yu Kuai <email address hidden> on 2022-06-22

nbd: make sure request completion won't concurrent

BugLink: https://bugs.launchpad.net/bugs/1896350

commit cddce0116058 ("nbd: Aovid double completion of a request")
try to fix that nbd_clear_que() and recv_work() can complete a
request concurrently. However, the problem still exists:

t1 t2 t3

nbd_disconnect_and_put
flush_workqueue
                      recv_work
                       blk_mq_complete_request
                        blk_mq_complete_request_remote -> this is true
                         WRITE_ONCE(rq->state, MQ_RQ_COMPLETE)
                          blk_mq_raise_softirq
                                             blk_done_softirq
                                              blk_complete_reqs
                                               nbd_complete_rq
                                                blk_mq_end_request
                                                 blk_mq_free_request
                                                  WRITE_ONCE(rq->state, MQ_RQ_IDLE)
  nbd_clear_que
   blk_mq_tagset_busy_iter
    nbd_clear_req
                                                   __blk_mq_free_request
                                                    blk_mq_put_tag
     blk_mq_complete_request -> complete again

There are three places where request can be completed in nbd:
recv_work(), nbd_clear_que() and nbd_xmit_timeout(). Since they
all hold cmd->lock before completing the request, it's easy to
avoid the problem by setting and checking a cmd flag.

Signed-off-by: Yu Kuai <email address hidden>
Reviewed-by: Ming Lei <email address hidden>
Reviewed-by: Josef Bacik <email address hidden>
Link: https://<email address hidden>
Signed-off-by: Jens Axboe <email address hidden>
(cherry picked from 07175cb1baf4c51051b1fbd391097e349f9a02a9)
Signed-off-by: Matthew Ruffell <email address hidden>
Acked-by: Tim Gardner <email address hidden>
Acked-by: Bartlomiej Zolnierkiewicz <email address hidden>
Signed-off-by: Tim Gardner <email address hidden>

db22205... by Yu Kuai <email address hidden> on 2022-06-22

nbd: don't handle response without a corresponding request message

BugLink: https://bugs.launchpad.net/bugs/1896350

While handling a response message from server, nbd_read_stat() will
try to get request by tag, and then complete the request. However,
this is problematic if nbd haven't sent a corresponding request
message:

t1 t2
                        submit_bio
                         nbd_queue_rq
                          blk_mq_start_request
recv_work
nbd_read_stat
  blk_mq_tag_to_rq
blk_mq_complete_request
                          nbd_send_cmd

Thus add a new cmd flag 'NBD_CMD_INFLIGHT', it will be set in
nbd_send_cmd() and checked in nbd_read_stat().

Noted that this patch can't fix that blk_mq_tag_to_rq() might
return a freed request, and this will be fixed in following
patches.

Signed-off-by: Yu Kuai <email address hidden>
Reviewed-by: Ming Lei <email address hidden>
Reviewed-by: Josef Bacik <email address hidden>
Link: https://<email address hidden>
Signed-off-by: Jens Axboe <email address hidden>
(cherry picked from 4e6eef5dc25b528e08ac5b5f64f6ca9d9987241d)
Signed-off-by: Matthew Ruffell <email address hidden>
Acked-by: Tim Gardner <email address hidden>
Acked-by: Bartlomiej Zolnierkiewicz <email address hidden>
Signed-off-by: Tim Gardner <email address hidden>

13f0723... by Thadeu Lima de Souza Cascardo on 2022-06-13