4.11-stable review patch. If anyone has any objections, please let me know.
------------------ From: Bart Van Assche <[email protected]> commit 7083abbbfc4fa706ff72d27d33a5214881979336 upstream. If blk_get_request() fails, check whether the failure is due to a path being removed. If that is the case, fail the path by triggering a call to fail_path(). This avoids that the following scenario can be encountered while removing paths: * CPU usage of a kworker thread jumps to 100%. * Removing the DM device becomes impossible. Delay requeueing if blk_get_request() returns -EBUSY or -EWOULDBLOCK, and the queue is not dying, because in these cases immediate requeuing is inappropriate. Signed-off-by: Bart Van Assche <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Christoph Hellwig <[email protected]> Signed-off-by: Mike Snitzer <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/md/dm-mpath.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -489,6 +489,7 @@ static int multipath_clone_and_map(struc struct pgpath *pgpath; struct block_device *bdev; struct dm_mpath_io *mpio = get_mpio(map_context); + struct request_queue *q; struct request *clone; /* Do we need to select a new pgpath? */ @@ -511,12 +512,18 @@ static int multipath_clone_and_map(struc mpio->nr_bytes = nr_bytes; bdev = pgpath->path.dev->bdev; - - clone = blk_get_request(bdev_get_queue(bdev), - rq->cmd_flags | REQ_NOMERGE, - GFP_ATOMIC); + q = bdev_get_queue(bdev); + clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, GFP_ATOMIC); if (IS_ERR(clone)) { /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ + bool queue_dying = blk_queue_dying(q); + DMERR_LIMIT("blk_get_request() returned %ld%s - requeuing", + PTR_ERR(clone), queue_dying ? " (path offline)" : ""); + if (queue_dying) { + atomic_inc(&m->pg_init_in_progress); + activate_or_offline_path(pgpath); + return DM_MAPIO_REQUEUE; + } return DM_MAPIO_DELAY_REQUEUE; } clone->bio = clone->biotail = NULL;
