diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2012-09-26 23:45:41 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2012-09-26 23:45:41 +0100 |
| commit | 7ba10aa6fbac7158a50bec142132b04bc480bb29 (patch) | |
| tree | 161bfefb7c6f3552ae723554f8725b0dff37314d | |
| parent | 307615a26e95406c42c95916a66ba50434567e0f (diff) | |
dm mpath: only retry ioctl when no paths if queue_if_no_path set
When there are no paths and multipath receives an ioctl, it waits until
a path becomes available. This behaviour is incorrect if the
"queue_if_no_path" setting was not specified, as then the ioctl should
be rejected immediately, which this patch now does.
commit 35991652b ("dm mpath: allow ioctls to trigger pg init") should
have checked if queue_if_no_path was configured before queueing IO.
Checking for the queue_if_no_path feature, like is done in map_io(),
allows the following table load to work without blocking in the
multipath_ioctl retry loop:
echo "0 1024 multipath 0 0 0 0" | dmsetup create mpath_nodevs
Without this fix the multipath_ioctl will block with the following stack
trace:
blkid D 0000000000000002 0 23936 1 0x00000000
ffff8802b89e5cd8 0000000000000082 ffff8802b89e5fd8 0000000000012440
ffff8802b89e4010 0000000000012440 0000000000012440 0000000000012440
ffff8802b89e5fd8 0000000000012440 ffff88030c2aab30 ffff880325794040
Call Trace:
[<ffffffff814ce099>] schedule+0x29/0x70
[<ffffffff814cc312>] schedule_timeout+0x182/0x2e0
[<ffffffff8104dee0>] ? lock_timer_base+0x70/0x70
[<ffffffff814cc48e>] schedule_timeout_uninterruptible+0x1e/0x20
[<ffffffff8104f840>] msleep+0x20/0x30
[<ffffffffa0000839>] multipath_ioctl+0x109/0x170 [dm_multipath]
[<ffffffffa06bfb9c>] dm_blk_ioctl+0xbc/0xd0 [dm_mod]
[<ffffffff8122a408>] __blkdev_driver_ioctl+0x28/0x30
[<ffffffff8122a79e>] blkdev_ioctl+0xce/0x730
[<ffffffff811970ac>] block_ioctl+0x3c/0x40
[<ffffffff8117321c>] do_vfs_ioctl+0x8c/0x340
[<ffffffff81166293>] ? sys_newfstat+0x33/0x40
[<ffffffff81173571>] sys_ioctl+0xa1/0xb0
[<ffffffff814d70a9>] system_call_fastpath+0x16/0x1b
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.5+
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
| -rw-r--r-- | drivers/md/dm-mpath.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index d8abb90a6c2f..034233eefc82 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1555,6 +1555,7 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg) { struct multipath *m = ti->private; + struct pgpath *pgpath; struct block_device *bdev; fmode_t mode; unsigned long flags; @@ -1570,12 +1571,14 @@ again: if (!m->current_pgpath) __choose_pgpath(m, 0); - if (m->current_pgpath) { - bdev = m->current_pgpath->path.dev->bdev; - mode = m->current_pgpath->path.dev->mode; + pgpath = m->current_pgpath; + + if (pgpath) { + bdev = pgpath->path.dev->bdev; + mode = pgpath->path.dev->mode; } - if (m->queue_io) + if ((pgpath && m->queue_io) || (!pgpath && m->queue_if_no_path)) r = -EAGAIN; else if (!bdev) r = -EIO; |