From: tang.junhui Date: Mon, 30 Oct 2017 21:46:34 +0000 (-0700) Subject: bcache: fix wrong cache_misses statistics X-Git-Tag: v3.18.89~12 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4ec687b9721e56dedf152041c1ed19ffe34020c;p=thirdparty%2Fkernel%2Fstable.git bcache: fix wrong cache_misses statistics [ Upstream commit c157313791a999646901b3e3c6888514ebc36d62 ] Currently, Cache missed IOs are identified by s->cache_miss, but actually, there are many situations that missed IOs are not assigned a value for s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO (s->iop.bypass = 1), or the cache_bio allocate failed. In these situations, it will go to out_put or out_submit, and s->cache_miss is null, which leads bch_mark_cache_accounting() to treat this IO as a hit IO. [ML: applied by 3-way merge] Signed-off-by: tang.junhui Reviewed-by: Michael Lyle Reviewed-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index ead0e6072af8f..92c7692f191d5 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -464,6 +464,7 @@ struct search { unsigned recoverable:1; unsigned write:1; unsigned read_dirty_data:1; + unsigned cache_missed:1; unsigned long start_time; @@ -651,6 +652,7 @@ static inline struct search *search_alloc(struct bio *bio, s->orig_bio = bio; s->cache_miss = NULL; + s->cache_missed = 0; s->d = d; s->recoverable = 1; s->write = (bio->bi_rw & REQ_WRITE) != 0; @@ -774,7 +776,7 @@ static void cached_dev_read_done_bh(struct closure *cl) struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); bch_mark_cache_accounting(s->iop.c, s->d, - !s->cache_miss, s->iop.bypass); + !s->cache_missed, s->iop.bypass); trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass); if (s->iop.error) @@ -793,6 +795,8 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); struct bio *miss, *cache_bio; + s->cache_missed = 1; + if (s->cache_miss || s->iop.bypass) { miss = bio_next_split(bio, sectors, GFP_NOIO, s->d->bio_split); ret = miss == bio ? MAP_DONE : MAP_CONTINUE;