Commit b2387ddc authored May 01, 2015 by Shaohua Li Committed by Jens Axboe May 04, 2015

blk-mq: fix FUA request hang



When a FUA request enters its DATA stage of flush pipeline, the
request is added to mq requeue list, the request will then be added to
ctx->rq_list. blk_mq_attempt_merge() might merge the request with a bio.
Later when the request is finished the flush pipeline, the
request->__data_len is 0. Then I only saw the bio gets endio called, the
original request never finish.

Adding REQ_FLUSH_SEQ into REQ_NOMERGE_FLAGS looks an easy fix.

stable: 3.15+

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 6cd18e71

include/linux/blk_types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -220,7 +220,7 @@ enum rq_flag_bits {

		/* This mask is used for both bio and request merge checking */
		#define REQ_NOMERGE_FLAGS \
		(REQ_NOMERGE \| REQ_STARTED \| REQ_SOFTBARRIER \| REQ_FLUSH \| REQ_FUA)
		(REQ_NOMERGE \| REQ_STARTED \| REQ_SOFTBARRIER \| REQ_FLUSH \| REQ_FUA \| REQ_FLUSH_SEQ)

		#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
		#define REQ_THROTTLED (1ULL << __REQ_THROTTLED)