[PATCH v3 01/30] block: Do not force full zone append completion in req_bio_endio()

[Jens Axboe]

On 3/28/24 4:43 PM, Damien Le Moal wrote:
> On 3/29/24 03:14, Bart Van Assche wrote:
>> On 3/27/24 17:43, Damien Le Moal wrote:
>>> This reverts commit 748dc0b65ec2b4b7b3dbd7befcc4a54fdcac7988.
>>>
>>> Partial zone append completions cannot be supported as there is no
>>> guarantees that the fragmented data will be written sequentially in the
>>> same manner as with a full command. Commit 748dc0b65ec2 ("block: fix
>>> partial zone append completion handling in req_bio_endio()") changed
>>> req_bio_endio() to always advance a partially failed BIO by its full
>>> length, but this can lead to incorrect accounting. So revert this
>>> change and let low level device drivers handle this case by always
>>> failing completely zone append operations. With this revert, users will
>>> still see an IO error for a partially completed zone append BIO.
>>>
>>> Fixes: 748dc0b65ec2 ("block: fix partial zone append completion handling in req_bio_endio()")
>>> Cc: stable at vger.kernel.org
>>> Signed-off-by: Damien Le Moal <dlemoal at kernel.org>
>>> ---
>>>   block/blk-mq.c | 9 ++-------
>>>   1 file changed, 2 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>>> index 555ada922cf0..32afb87efbd0 100644
>>> --- a/block/blk-mq.c
>>> +++ b/block/blk-mq.c
>>> @@ -770,16 +770,11 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
>>>   		/*
>>>   		 * Partial zone append completions cannot be supported as the
>>>   		 * BIO fragments may end up not being written sequentially.
>>> -		 * For such case, force the completed nbytes to be equal to
>>> -		 * the BIO size so that bio_advance() sets the BIO remaining
>>> -		 * size to 0 and we end up calling bio_endio() before returning.
>>>   		 */
>>> -		if (bio->bi_iter.bi_size != nbytes) {
>>> +		if (bio->bi_iter.bi_size != nbytes)
>>>   			bio->bi_status = BLK_STS_IOERR;
>>> -			nbytes = bio->bi_iter.bi_size;
>>> -		} else {
>>> +		else
>>>   			bio->bi_iter.bi_sector = rq->__sector;
>>> -		}
>>>   	}
>>>   
>>>   	bio_advance(bio, nbytes);
>>
>> Hi Damien,
>>
>> This patch looks good to me but shouldn't it be separated from this
>> patch series? I think that will help this patch to get merged sooner.
> 
> Yes, it can go on its own. But patch 3 depends on it so I kept it in the series.
> 
> Jens,
> 
> How would you like to proceed with this one ?

I can just pick it up separately.

-- 
Jens Axboe