dm: fix ioctl retry termination with signal

dm-mpath retries ioctl, when no path is readily available and the device
is configured to queue I/O in such a case. If you want to stop the retry
before multipathd decides to turn off queueing mode, you could send
signal for the process to exit from the loop.

However the check of fatal signal has not carried along when commit
6c182cd88d17 ("dm mpath: fix ioctl deadlock when no paths") moved the
loop from dm-mpath to dm core. As a result, we can't terminate such
a process in the retry loop.

Easy reproducer of the situation is:

  # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
  # dmsetup message mp 0 'queue_if_no_path'
  # sg_inq /dev/mapper/mp

then you should be able to terminate sg_inq by pressing Ctrl+C.

Fixes: 6c182cd88d17 ("dm mpath: fix ioctl deadlock when no paths")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index aaa6caa46a9f2dbceaf3d9c1aac92037b3b731b2..3d1829237678d2c254125713c7ff9ede4b6bcada 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1562,7 +1562,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
 
        spin_unlock_irqrestore(&m->lock, flags);
 
-       if (r == -ENOTCONN && !fatal_signal_pending(current)) {
+       if (r == -ENOTCONN) {
                spin_lock_irqsave(&m->lock, flags);
                if (!m->current_pg) {
                        /* Path status changed, redo selection */

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6e15f3565892fce8315cef992e0b2721e8c20088..fabd5d8fd5594403eef204e18e8b791581676ac3 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -591,7 +591,7 @@ retry:
 
 out:
        dm_put_live_table(md, *srcu_idx);
-       if (r == -ENOTCONN) {
+       if (r == -ENOTCONN && !fatal_signal_pending(current)) {
                msleep(10);
                goto retry;
        }