Re: [PATCH] blk-mq: fix FUA request hang

From: Jens Axboe
Date: Mon May 04 2015 - 15:11:11 EST


On 05/01/2015 10:59 AM, Shaohua Li wrote:
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.

Thanks, applied.

--
Jens Axboe

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