[dm-devel] dm-mq and end_clone_request()

[Bart Van Assche]

On 07/20/2016 11:33 AM, Mike Snitzer wrote:
> Would be interesting to know the error returned from map_request()'s
> ti->type->clone_and_map_rq().  Really should just be DM_MAPIO_REQUEUE.
> But the stack you've provided shows map_request calling
> dm_complete_request(), which implies dm_kill_unmapped_request() is being
> called due to ti->type->clone_and_map_rq() returning < 0.

Hello Mike,

Apparently certain requests fail with -EIO because DM_DEV_SUSPEND ioctls 
are being submitted to the same multipath target. As you know 
DM_DEV_SUSPEND changes QUEUE_IF_NO_PATH from 1 into 0. A WARN_ON() 
statement that I added in driver dm-mpath statement learned me that 
multipathd is submitting these DM_DEV_SUSPEND ioctls. In the output of 
strace -fp$(pidof multipathd) I found the following:

[pid 13927] ioctl(5, DM_TABLE_STATUS, 0x7fa1000483f0) = 0
[pid 13927] write(1, "mpathbe: failed to setup multipa"..., 35) = 35
[pid 13927] write(1, "dm-0: uev_add_map failed\n", 25) = 25
[pid 13927] write(1, "uevent trigger error\n", 21) = 21
[pid 13927] write(1, "sdh: remove path (uevent)\n", 26) = 26
[pid 13927] ioctl(5, DM_TABLE_LOAD, 0x7fa1000483f0) = 0
[pid 13927] ioctl(5, DM_DEV_SUSPEND, 0x7fa1000483f0) = 0

I'm still analyzing these and other messages.

Bart.