Add 'features' member to 'struct multipath' and introduce MPF_ABORT_QUEUE as the first feature flag. If "abort_queue_on_failure" is provided during mpath device configuration the MPF_ABORT_QUEUE feature flag will be set and blk_abort_queue() will be called during path failure to allow for lower latency path failures. But this feature has been disabled by default due to a race (between blk_abort_queue and scsi_request_fn) that can lead to list corruption, from: https://www.redhat.com/archives/dm-devel/2010-November/msg00085.html "the cmd gets blk_abort_queued/timedout run on it and the scsi eh somehow is able to complete and run scsi_queue_insert while scsi_request_fn is still trying to process the request." Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> Cc: Mike Christie <michaelc@xxxxxxxxxxx> --- drivers/md/dm-mpath.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) Index: linux-2.6/drivers/md/dm-mpath.c =================================================================== --- linux-2.6.orig/drivers/md/dm-mpath.c +++ linux-2.6/drivers/md/dm-mpath.c @@ -56,8 +56,14 @@ struct priority_group { struct list_head pgpaths; }; +/* + * Bits for the m->features + */ +#define MPF_ABORT_QUEUE 0 + /* Multipath context */ struct multipath { + unsigned long features; struct list_head list; struct dm_target *ti; @@ -146,7 +152,8 @@ static void deactivate_path(struct work_ struct pgpath *pgpath = container_of(work, struct pgpath, deactivate_path); - blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); + if (test_bit(MPF_ABORT_QUEUE, &pgpath->pg->m->features)) + blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); } static struct priority_group *alloc_priority_group(void) @@ -813,6 +820,11 @@ static int parse_features(struct arg_set continue; } + if (!strnicmp(param_name, MESG_STR("abort_queue_on_failure"))) { + set_bit(MPF_ABORT_QUEUE, &m->features); + continue; + } + if (!strnicmp(param_name, MESG_STR("pg_init_retries")) && (argc >= 1)) { r = read_param(_params + 1, shift(as), @@ -1382,11 +1394,14 @@ static int multipath_status(struct dm_ta DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); else { DMEMIT("%u ", m->queue_if_no_path + - (m->pg_init_retries > 0) * 2); + (m->pg_init_retries > 0) * 2 + + test_bit(MPF_ABORT_QUEUE, &m->features)); if (m->queue_if_no_path) DMEMIT("queue_if_no_path "); if (m->pg_init_retries) DMEMIT("pg_init_retries %u ", m->pg_init_retries); + if (test_bit(MPF_ABORT_QUEUE, &m->features)) + DMEMIT("abort_queue_on_failure "); } if (!m->hw_handler_name || type == STATUSTYPE_INFO) -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
