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Commit 86331f39 authored by Bart Van Assche's avatar Bart Van Assche Committed by Mike Snitzer
Browse files

dm mpath: make it easier to detect unintended I/O request flushes 



I/O errors triggered by multipathd incorrectly not enabling the no-flush
flag for DM_DEVICE_SUSPEND or DM_DEVICE_RESUME are hard to debug.  Add
more logging to make it easier to debug this.

Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 9a8ac3ae

drivers/md/dm-mpath.c

+21 −4
Original line number Diff line number Diff line
@@ -441,6 +441,23 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) 
	return NULL;

}



/*

 * dm_report_EIO() is a macro instead of a function to make pr_debug()

 * report the function name and line number of the function from which

 * it has been invoked.

 */

#define dm_report_EIO(m)						\

({									\

	struct mapped_device *md = dm_table_get_md((m)->ti->table);	\

									\

	pr_debug("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d\n", \

		 dm_device_name(md),					\

		 test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags),	\

		 test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags),	\

		 dm_noflush_suspending((m)->ti));			\

	-EIO;								\

})



/*

 * Map cloned requests (request-based multipath)

 */
@@ -464,7 +481,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, 
	if (!pgpath) {

		if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))

			return DM_MAPIO_DELAY_REQUEUE;

		return -EIO;	/* Failed */

		return dm_report_EIO(m);	/* Failed */

	} else if (test_bit(MPATHF_QUEUE_IO, &m->flags) ||

		   test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) {

		if (pg_init_all_paths(m))
@@ -541,7 +558,7 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_m 
	if (!pgpath) {

		if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))

			return DM_MAPIO_REQUEUE;

		return -EIO;

		return dm_report_EIO(m);

	}



	mpio->pgpath = pgpath;
@@ -1476,7 +1493,7 @@ static int do_end_io(struct multipath *m, struct request *clone, 


	if (atomic_read(&m->nr_valid_paths) == 0 &&

	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))

		r = -EIO;

		r = dm_report_EIO(m);



	return r;

}
@@ -1519,7 +1536,7 @@ static int do_end_io_bio(struct multipath *m, struct bio *clone, 


	if (atomic_read(&m->nr_valid_paths) == 0 &&

	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))

		return -EIO;

		return dm_report_EIO(m);



	/* Queue for the daemon to resubmit */

	dm_bio_restore(get_bio_details_from_bio(clone), clone);

drivers/md/dm.c

+2 −0
Original line number Diff line number Diff line
@@ -2169,6 +2169,8 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, 
	 */

	if (noflush)

		set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);

	else

		pr_debug("%s: suspending with flush\n", dm_device_name(md));



	/*

	 * This gets reverted if there's an error later and the targets