3.16.63-rc1 review patch. If anyone has any objections, please let me know.
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From: "tang.junhui" tang.junhui@zte.com.cn
commit c157313791a999646901b3e3c6888514ebc36d62 upstream.
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 tang.junhui@zte.com.cn Reviewed-by: Michael Lyle mlyle@lyle.org Reviewed-by: Coly Li colyli@suse.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/md/bcache/request.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -462,6 +462,7 @@ 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_allo
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(stru 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 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;