diff options
| author | Hannes Reinecke <hare@suse.de> | 2013-07-10 23:41:15 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2013-07-10 23:41:15 +0100 |
| commit | 6c182cd88d179cbbd06f4f8a8a19b6977940753f (patch) | |
| tree | 27971aeafbdd2410699e77477565157c67d8ffea /drivers/md/dm-mpath.c | |
| parent | 8bb495e3f02401ee6f76d1b1d77f3ac9f079e376 (diff) | |
dm mpath: fix ioctl deadlock when no paths
When multipath needs to retry an ioctl the reference to the
current live table needs to be dropped. Otherwise a deadlock
occurs when all paths are down:
- dm_blk_ioctl takes a reference to the current table
and spins in multipath_ioctl().
- A new table is being loaded, but upon resume the process
hangs in dm_table_destroy() waiting for references to
drop to zero.
With this patch the reference to the old table is dropped
prior to retry, thereby avoiding the deadlock.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-mpath.c')
| -rw-r--r-- | drivers/md/dm-mpath.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index bdf26f5bd326..5adede17ddf6 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1561,7 +1561,6 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long flags; int r; -again: bdev = NULL; mode = 0; r = 0; @@ -1579,7 +1578,7 @@ again: } if ((pgpath && m->queue_io) || (!pgpath && m->queue_if_no_path)) - r = -EAGAIN; + r = -ENOTCONN; else if (!bdev) r = -EIO; @@ -1591,11 +1590,8 @@ again: if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT) r = scsi_verify_blk_ioctl(NULL, cmd); - if (r == -EAGAIN && !fatal_signal_pending(current)) { + if (r == -ENOTCONN && !fatal_signal_pending(current)) queue_work(kmultipathd, &m->process_queued_ios); - msleep(10); - goto again; - } return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); } |