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.c | |
parent | 8bb495e3f02401ee6f76d1b1d77f3ac9f079e376 (diff) | |
download | blackbird-op-linux-6c182cd88d179cbbd06f4f8a8a19b6977940753f.tar.gz blackbird-op-linux-6c182cd88d179cbbd06f4f8a8a19b6977940753f.zip |
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.c')
-rw-r--r-- | drivers/md/dm.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index d5370a94b2c1..33f20103d8d5 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -386,10 +386,12 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { struct mapped_device *md = bdev->bd_disk->private_data; - struct dm_table *map = dm_get_live_table(md); + struct dm_table *map; struct dm_target *tgt; int r = -ENOTTY; +retry: + map = dm_get_live_table(md); if (!map || !dm_table_get_size(map)) goto out; @@ -410,6 +412,11 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, out: dm_table_put(map); + if (r == -ENOTCONN) { + msleep(10); + goto retry; + } + return r; } |