Commit 27a40ab9 authored by Coly Li's avatar Coly Li Committed by Jens Axboe
Browse files

bcache: add backing_request_endio() for bi_end_io 



In order to catch I/O error of backing device, a separate bi_end_io
call back is required. Then a per backing device counter can record I/O
errors number and retire the backing device if the counter reaches a
per backing device I/O error limit.

This patch adds backing_request_endio() to bcache backing device I/O code
path, this is a preparation for further complicated backing device failure
handling. So far there is no real code logic change, I make this change a
separate patch to make sure it is stable and reliable for further work.

Changelog:
v2: Fix code comments typo, remove a redundant bch_writeback_add() line
    added in v4 patch set.
v1: indeed this is new added in this patch set.

[mlyle: truncated commit subject]

Signed-off-by: default avatarColy Li <colyli@suse.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
Cc: Junhui Tang <tang.junhui@zte.com.cn>
Cc: Michael Lyle <mlyle@lyle.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent df2b9431

drivers/md/bcache/request.c

+77 −16
Original line number Diff line number Diff line
@@ -139,6 +139,7 @@ static void bch_data_invalidate(struct closure *cl) 
	}



	op->insert_data_done = true;

	/* get in bch_data_insert() */

	bio_put(bio);

out:

	continue_at(cl, bch_data_insert_keys, op->wq);
@@ -630,6 +631,38 @@ static void request_endio(struct bio *bio) 
	closure_put(cl);

}



static void backing_request_endio(struct bio *bio)

{

	struct closure *cl = bio->bi_private;



	if (bio->bi_status) {

		struct search *s = container_of(cl, struct search, cl);

		/*

		 * If a bio has REQ_PREFLUSH for writeback mode, it is

		 * speically assembled in cached_dev_write() for a non-zero

		 * write request which has REQ_PREFLUSH. we don't set

		 * s->iop.status by this failure, the status will be decided

		 * by result of bch_data_insert() operation.

		 */

		if (unlikely(s->iop.writeback &&

			     bio->bi_opf & REQ_PREFLUSH)) {

			char buf[BDEVNAME_SIZE];



			bio_devname(bio, buf);

			pr_err("Can't flush %s: returned bi_status %i",

				buf, bio->bi_status);

		} else {

			/* set to orig_bio->bi_status in bio_complete() */

			s->iop.status = bio->bi_status;

		}

		s->recoverable = false;

		/* should count I/O error for backing device here */

	}



	bio_put(bio);

	closure_put(cl);

}



static void bio_complete(struct search *s)

{

	if (s->orig_bio) {
@@ -644,13 +677,21 @@ static void bio_complete(struct search *s) 
	}

}



static void do_bio_hook(struct search *s, struct bio *orig_bio)

static void do_bio_hook(struct search *s,

			struct bio *orig_bio,

			bio_end_io_t *end_io_fn)

{

	struct bio *bio = &s->bio.bio;



	bio_init(bio, NULL, 0);

	__bio_clone_fast(bio, orig_bio);

	bio->bi_end_io		= request_endio;

	/*

	 * bi_end_io can be set separately somewhere else, e.g. the

	 * variants in,

	 * - cache_bio->bi_end_io from cached_dev_cache_miss()

	 * - n->bi_end_io from cache_lookup_fn()

	 */

	bio->bi_end_io		= end_io_fn;

	bio->bi_private		= &s->cl;



	bio_cnt_set(bio, 3);
@@ -676,7 +717,7 @@ static inline struct search *search_alloc(struct bio *bio, 
	s = mempool_alloc(d->c->search, GFP_NOIO);



	closure_init(&s->cl, NULL);

	do_bio_hook(s, bio);

	do_bio_hook(s, bio, request_endio);



	s->orig_bio		= bio;

	s->cache_miss		= NULL;
@@ -743,10 +784,11 @@ static void cached_dev_read_error(struct closure *cl) 
		trace_bcache_read_retry(s->orig_bio);



		s->iop.status = 0;

		do_bio_hook(s, s->orig_bio);

		do_bio_hook(s, s->orig_bio, backing_request_endio);



		/* XXX: invalidate cache */



		/* I/O request sent to backing device */

		closure_bio_submit(s->iop.c, bio, cl);

	}
@@ -859,7 +901,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, 
	bio_copy_dev(cache_bio, miss);

	cache_bio->bi_iter.bi_size	= s->insert_bio_sectors << 9;



	cache_bio->bi_end_io	= request_endio;

	cache_bio->bi_end_io	= backing_request_endio;

	cache_bio->bi_private	= &s->cl;



	bch_bio_map(cache_bio, NULL);
@@ -872,14 +914,16 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, 
	s->cache_miss	= miss;

	s->iop.bio	= cache_bio;

	bio_get(cache_bio);

	/* I/O request sent to backing device */

	closure_bio_submit(s->iop.c, cache_bio, &s->cl);



	return ret;

out_put:

	bio_put(cache_bio);

out_submit:

	miss->bi_end_io		= request_endio;

	miss->bi_end_io		= backing_request_endio;

	miss->bi_private	= &s->cl;

	/* I/O request sent to backing device */

	closure_bio_submit(s->iop.c, miss, &s->cl);

	return ret;

}
@@ -943,31 +987,46 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s) 
		s->iop.bio = s->orig_bio;

		bio_get(s->iop.bio);



		if ((bio_op(bio) != REQ_OP_DISCARD) ||

		    blk_queue_discard(bdev_get_queue(dc->bdev)))

		if (bio_op(bio) == REQ_OP_DISCARD &&

		    !blk_queue_discard(bdev_get_queue(dc->bdev)))

			goto insert_data;



		/* I/O request sent to backing device */

		bio->bi_end_io = backing_request_endio;

		closure_bio_submit(s->iop.c, bio, cl);



	} else if (s->iop.writeback) {

		bch_writeback_add(dc);

		s->iop.bio = bio;



		if (bio->bi_opf & REQ_PREFLUSH) {

			/* Also need to send a flush to the backing device */

			struct bio *flush = bio_alloc_bioset(GFP_NOIO, 0,

							     dc->disk.bio_split);

			/*

			 * Also need to send a flush to the backing

			 * device.

			 */

			struct bio *flush;



			flush = bio_alloc_bioset(GFP_NOIO, 0,

						 dc->disk.bio_split);

			if (!flush) {

				s->iop.status = BLK_STS_RESOURCE;

				goto insert_data;

			}

			bio_copy_dev(flush, bio);

			flush->bi_end_io = request_endio;

			flush->bi_end_io = backing_request_endio;

			flush->bi_private = cl;

			flush->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;



			/* I/O request sent to backing device */

			closure_bio_submit(s->iop.c, flush, cl);

		}

	} else {

		s->iop.bio = bio_clone_fast(bio, GFP_NOIO, dc->disk.bio_split);



		/* I/O request sent to backing device */

		bio->bi_end_io = backing_request_endio;

		closure_bio_submit(s->iop.c, bio, cl);

	}



insert_data:

	closure_call(&s->iop.cl, bch_data_insert, NULL, cl);

	continue_at(cl, cached_dev_write_complete, NULL);

}
@@ -981,6 +1040,7 @@ static void cached_dev_nodata(struct closure *cl) 
		bch_journal_meta(s->iop.c, cl);



	/* If it's a flush, we send the flush to the backing device too */

	bio->bi_end_io = backing_request_endio;

	closure_bio_submit(s->iop.c, bio, cl);



	continue_at(cl, cached_dev_bio_complete, NULL);
@@ -1078,6 +1138,7 @@ static blk_qc_t cached_dev_make_request(struct request_queue *q, 
				cached_dev_read(dc, s);

		}

	} else

		/* I/O request sent to backing device */

		detached_dev_do_request(d, bio);



	return BLK_QC_T_NONE;

drivers/md/bcache/super.c

+1 −0
Original line number Diff line number Diff line
@@ -273,6 +273,7 @@ void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent) 
	bio->bi_private = dc;



	closure_get(cl);

	/* I/O request sent to backing device */

	__write_super(&dc->sb, bio);



	closure_return_with_destructor(cl, bch_write_bdev_super_unlock);

drivers/md/bcache/writeback.c

+1 −0
Original line number Diff line number Diff line
@@ -289,6 +289,7 @@ static void write_dirty(struct closure *cl) 
		bio_set_dev(&io->bio, io->dc->bdev);

		io->bio.bi_end_io	= dirty_endio;



		/* I/O request sent to backing device */

		closure_bio_submit(io->dc->disk.c, &io->bio, cl);

	}

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