Changes in v4
- in patch 3, return from nbd_handle_reply() with flag cleared if
request is ready to complete.
- add reviewed-by tag for patch 1-2, 4-6.
Changes in v3:
- rewrap to 80 columns where possible in patch 6
Changes in v2:
- in patch 3, instead of clear and then reset the flag if rq is not
completed, test first and clear if rq is going to complete.
path 1-2 fix races between nbd setup and module removal.
patch 3 fix io can't be completed in some error path.
patch 4 fix io hung when disconnecting failed.
patch 5 fix sysfs warning about duplicate creation.
patch 6 use pr_err to output error message.
Previous versions:
v1: https://lore.kernel.org/all/[email protected]/
v2: https://lore.kernel.org/all/[email protected]/
v3: https://lore.kernel.org/all/[email protected]/
Yu Kuai (5):
nbd: call genl_unregister_family() first in nbd_cleanup()
nbd: fix race between nbd_alloc_config() and module removal
nbd: don't clear 'NBD_CMD_INFLIGHT' flag if request is not completed
nbd: fix io hung while disconnecting device
nbd: use pr_err to output error message
Zhang Wensheng (1):
nbd: fix possible overflow on 'first_minor' in nbd_dev_add()
drivers/block/nbd.c | 109 +++++++++++++++++++++++++-------------------
1 file changed, 63 insertions(+), 46 deletions(-)
--
2.31.1
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 protected]>
Reviewed-by: Josef Bacik <[email protected]>
---
drivers/block/nbd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index a673a97b9b6b..d536bca0a9a2 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1424,7 +1424,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd)
static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
struct block_device *bdev)
{
- sock_shutdown(nbd);
+ nbd_clear_sock(nbd);
__invalidate_device(bdev, true);
nbd_bdev_reset(nbd);
if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
--
2.31.1