Commit 485ef69e authored by Alasdair G Kergon's avatar Alasdair G Kergon Committed by Linus Torvalds
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[PATCH] device-mapper: Fix queue_if_no_path initialisation 



When creating a multipath device, if the queue_if_no_path parameter is
specified it gets ignored.

While the queue_if_no_path variable is correctly set to 1, the
saved_queue_if_no_path gets set to 0.  When the device is subsequently made
live (resumed), the saved value (0) always overwrites the live value (1) so
the option *always* gets turned off.

The fix adds a parameter to the queue_if_no_path() function to indicate
whether the previous value should be preserved or not - if not, as when the
device is being set up, the saved value is set to the new value (1).

Signed-Off-By: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 269fd2a6

drivers/md/dm-mpath.c

+10 −6
Original line number Diff line number Diff line
@@ -329,13 +329,17 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio, 
/*

 * If we run out of usable paths, should we queue I/O or error it?

 */

static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)

static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path,

			    unsigned save_old_value)

{

	unsigned long flags;



	spin_lock_irqsave(&m->lock, flags);



	if (save_old_value)

		m->saved_queue_if_no_path = m->queue_if_no_path;

	else

		m->saved_queue_if_no_path = queue_if_no_path;

	m->queue_if_no_path = queue_if_no_path;

	if (!m->queue_if_no_path && m->queue_size)

		queue_work(kmultipathd, &m->process_queued_ios);
@@ -677,7 +681,7 @@ static int parse_features(struct arg_set *as, struct multipath *m, 
		return 0;



	if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))

		return queue_if_no_path(m, 1);

		return queue_if_no_path(m, 1, 0);

	else {

		ti->error = "Unrecognised multipath feature request";

		return -EINVAL;
@@ -1077,7 +1081,7 @@ static void multipath_presuspend(struct dm_target *ti) 
{

	struct multipath *m = (struct multipath *) ti->private;



	queue_if_no_path(m, 0);

	queue_if_no_path(m, 0, 1);

}



/*
@@ -1222,9 +1226,9 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) 


	if (argc == 1) {

		if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))

			return queue_if_no_path(m, 1);

			return queue_if_no_path(m, 1, 0);

		else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))

			return queue_if_no_path(m, 0);

			return queue_if_no_path(m, 0, 0);

	}



	if (argc != 2)

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