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path: root/drivers/md/bcache/request.c
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Diffstat (limited to 'drivers/md/bcache/request.c')
-rw-r--r--drivers/md/bcache/request.c36
1 files changed, 28 insertions, 8 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 3475d6628e21..3a7aed7282b2 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -27,12 +27,12 @@ struct kmem_cache *bch_search_cache;
static void bch_data_insert_start(struct closure *);
-static unsigned cache_mode(struct cached_dev *dc, struct bio *bio)
+static unsigned cache_mode(struct cached_dev *dc)
{
return BDEV_CACHE_MODE(&dc->sb);
}
-static bool verify(struct cached_dev *dc, struct bio *bio)
+static bool verify(struct cached_dev *dc)
{
return dc->verify;
}
@@ -370,7 +370,7 @@ static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k)
static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
{
struct cache_set *c = dc->disk.c;
- unsigned mode = cache_mode(dc, bio);
+ unsigned mode = cache_mode(dc);
unsigned sectors, congested = bch_get_congested(c);
struct task_struct *task = current;
struct io *i;
@@ -385,6 +385,14 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
op_is_write(bio_op(bio))))
goto skip;
+ /*
+ * Flag for bypass if the IO is for read-ahead or background,
+ * unless the read-ahead request is for metadata (eg, for gfs2).
+ */
+ if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) &&
+ !(bio->bi_opf & REQ_META))
+ goto skip;
+
if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) ||
bio_sectors(bio) & (c->sb.block_size - 1)) {
pr_debug("skipping unaligned io");
@@ -463,6 +471,7 @@ struct search {
unsigned recoverable:1;
unsigned write:1;
unsigned read_dirty_data:1;
+ unsigned cache_missed:1;
unsigned long start_time;
@@ -649,6 +658,7 @@ 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 = op_is_write(bio_op(bio));
@@ -698,8 +708,16 @@ static void cached_dev_read_error(struct closure *cl)
{
struct search *s = container_of(cl, struct search, cl);
struct bio *bio = &s->bio.bio;
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
- if (s->recoverable) {
+ /*
+ * If cache device is dirty (dc->has_dirty is non-zero), then
+ * recovery a failed read request from cached device may get a
+ * stale data back. So read failure recovery is only permitted
+ * when cache device is clean.
+ */
+ if (s->recoverable &&
+ (dc && !atomic_read(&dc->has_dirty))) {
/* Retry from the backing device: */
trace_bcache_read_retry(s->orig_bio);
@@ -740,7 +758,7 @@ static void cached_dev_read_done(struct closure *cl)
s->cache_miss = NULL;
}
- if (verify(dc, &s->bio.bio) && s->recoverable && !s->read_dirty_data)
+ if (verify(dc) && s->recoverable && !s->read_dirty_data)
bch_data_verify(dc, s->orig_bio);
bio_complete(s);
@@ -760,12 +778,12 @@ 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.status)
continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq);
- else if (s->iop.bio || verify(dc, &s->bio.bio))
+ else if (s->iop.bio || verify(dc))
continue_at_nobarrier(cl, cached_dev_read_done, bcache_wq);
else
continue_at_nobarrier(cl, cached_dev_bio_complete, NULL);
@@ -779,6 +797,8 @@ 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;
@@ -892,7 +912,7 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s)
s->iop.bypass = true;
if (should_writeback(dc, s->orig_bio,
- cache_mode(dc, bio),
+ cache_mode(dc),
s->iop.bypass)) {
s->iop.bypass = false;
s->iop.writeback = true;