Let dm-mpath fail requests if queue_if_no_path is enabled and request flag REQ_FAIL_IF_NO_PATH has been set. This facility will be used in the next patch to fix a deadlock between SCSI device removal and sd event checking.
Signed-off-by: Bart Van Assche <[email protected]> Cc: Mike Snitzer <[email protected]> Cc: Hannes Reinecke <[email protected]> --- drivers/md/dm-mpath.c | 6 ++++-- include/linux/blk_types.h | 4 ++++ 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 1c97f0e..9348151 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -539,6 +539,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, struct multipath *m = ti->private; int r = DM_MAPIO_REQUEUE; size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq); + bool fail_if_no_path = (clone ? : rq)->cmd_flags & REQ_FAIL_IF_NO_PATH; struct pgpath *pgpath; struct block_device *bdev; struct dm_mpath_io *mpio; @@ -549,7 +550,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, pgpath = choose_pgpath(m, nr_bytes); if (!pgpath) { - if (must_push_back_rq(m)) + if (!fail_if_no_path && must_push_back_rq(m)) return DM_MAPIO_DELAY_REQUEUE; return -EIO; /* Failed */ } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || @@ -1567,6 +1568,7 @@ static int do_end_io(struct multipath *m, struct request *clone, * clone bios for it and resubmit it later. */ int r = DM_ENDIO_REQUEUE; + bool fail_if_no_path = clone->cmd_flags & REQ_FAIL_IF_NO_PATH; if (!error && !clone->errors) return 0; /* I/O complete */ @@ -1579,7 +1581,7 @@ static int do_end_io(struct multipath *m, struct request *clone, if (!atomic_read(&m->nr_valid_paths)) { if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { - if (!must_push_back_rq(m)) + if (fail_if_no_path || !must_push_back_rq(m)) r = -EIO; } } diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index cd395ec..9b25728 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -189,6 +189,9 @@ enum rq_flag_bits { __REQ_PM, /* runtime pm request */ __REQ_HASHED, /* on IO scheduler merge hash */ __REQ_MQ_INFLIGHT, /* track inflight for MQ */ + + __REQ_FAIL_IF_NO_PATH, /* fail if queued on dm-mpath with no paths */ + __REQ_NR_BITS, /* stops here */ }; @@ -235,6 +238,7 @@ enum rq_flag_bits { #define REQ_PM (1ULL << __REQ_PM) #define REQ_HASHED (1ULL << __REQ_HASHED) #define REQ_MQ_INFLIGHT (1ULL << __REQ_MQ_INFLIGHT) +#define REQ_FAIL_IF_NO_PATH (1ULL << __REQ_FAIL_IF_NO_PATH) enum req_op { REQ_OP_READ, -- 2.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
