Multipath was previously made to use blk_abort_queue() to allow for lower latency path deactivation (commit 224cb3e9). The call to blk_abort_queue has proven to be unsafe 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." It is hoped that this race will be fixed soon so it makes little sense to remove all associated code at this point. Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> Cc: Mike Christie <michaelc@xxxxxxxxxxx> --- drivers/md/dm-mpath.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 487ecda..6292e41 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -24,6 +24,9 @@ #define DM_MSG_PREFIX "multipath" #define MESG_STR(x) x, sizeof(x) +/* Avoid calling blk_abort_queue until race with scsi_request_fn is fixed */ +#define MPATH_CALL_BLK_ABORT_QUEUE 0 + /* Path properties */ struct pgpath { struct list_head list; @@ -33,7 +36,9 @@ struct pgpath { unsigned fail_count; /* Cumulative failure count */ struct dm_path path; +#if MPATH_CALL_BLK_ABORT_QUEUE struct work_struct deactivate_path; +#endif struct work_struct activate_path; }; @@ -116,7 +121,9 @@ static struct workqueue_struct *kmultipathd, *kmpath_handlerd; static void process_queued_ios(struct work_struct *work); static void trigger_event(struct work_struct *work); static void activate_path(struct work_struct *work); +#if MPATH_CALL_BLK_ABORT_QUEUE static void deactivate_path(struct work_struct *work); +#endif /*----------------------------------------------- @@ -129,7 +136,9 @@ static struct pgpath *alloc_pgpath(void) if (pgpath) { pgpath->is_active = 1; +#if MPATH_CALL_BLK_ABORT_QUEUE INIT_WORK(&pgpath->deactivate_path, deactivate_path); +#endif INIT_WORK(&pgpath->activate_path, activate_path); } @@ -141,6 +150,7 @@ static void free_pgpath(struct pgpath *pgpath) kfree(pgpath); } +#if MPATH_CALL_BLK_ABORT_QUEUE static void deactivate_path(struct work_struct *work) { struct pgpath *pgpath = @@ -148,6 +158,7 @@ static void deactivate_path(struct work_struct *work) blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); } +#endif static struct priority_group *alloc_priority_group(void) { @@ -995,7 +1006,9 @@ static int fail_path(struct pgpath *pgpath) pgpath->path.dev->name, m->nr_valid_paths); schedule_work(&m->trigger_event); +#if MPATH_CALL_BLK_ABORT_QUEUE queue_work(kmultipathd, &pgpath->deactivate_path); +#endif out: spin_unlock_irqrestore(&m->lock, flags); -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
