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Diffstat (limited to 'drivers/md/bcache/request.c')
-rw-r--r--drivers/md/bcache/request.c64
1 files changed, 53 insertions, 11 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 3475d6628e21..1a46b41dac70 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;
@@ -567,6 +576,7 @@ static void cache_lookup(struct closure *cl)
{
struct search *s = container_of(cl, struct search, iop.cl);
struct bio *bio = &s->bio.bio;
+ struct cached_dev *dc;
int ret;
bch_btree_op_init(&s->op, -1);
@@ -579,6 +589,27 @@ static void cache_lookup(struct closure *cl)
return;
}
+ /*
+ * We might meet err when searching the btree, If that happens, we will
+ * get negative ret, in this scenario we should not recover data from
+ * backing device (when cache device is dirty) because we don't know
+ * whether bkeys the read request covered are all clean.
+ *
+ * And after that happened, s->iop.status is still its initial value
+ * before we submit s->bio.bio
+ */
+ if (ret < 0) {
+ BUG_ON(ret == -EINTR);
+ if (s->d && s->d->c &&
+ !UUID_FLASH_ONLY(&s->d->c->uuids[s->d->id])) {
+ dc = container_of(s->d, struct cached_dev, disk);
+ if (dc && atomic_read(&dc->has_dirty))
+ s->recoverable = false;
+ }
+ if (!s->iop.status)
+ s->iop.status = BLK_STS_IOERR;
+ }
+
closure_return(cl);
}
@@ -602,8 +633,8 @@ static void request_endio(struct bio *bio)
static void bio_complete(struct search *s)
{
if (s->orig_bio) {
- struct request_queue *q = s->orig_bio->bi_disk->queue;
- generic_end_io_acct(q, bio_data_dir(s->orig_bio),
+ generic_end_io_acct(s->d->disk->queue,
+ bio_data_dir(s->orig_bio),
&s->d->disk->part0, s->start_time);
trace_bcache_request_end(s->d, s->orig_bio);
@@ -649,6 +680,7 @@ 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));
@@ -699,7 +731,14 @@ static void cached_dev_read_error(struct closure *cl)
struct search *s = container_of(cl, struct search, cl);
struct bio *bio = &s->bio.bio;
- if (s->recoverable) {
+ /*
+ * If read request hit dirty data (s->read_dirty_data is true),
+ * then recovery a failed read request from cached device may
+ * get a stale data back. So read failure recovery is only
+ * permitted when read request hit clean data in cache device,
+ * or when cache read race happened.
+ */
+ if (s->recoverable && !s->read_dirty_data) {
/* Retry from the backing device: */
trace_bcache_read_retry(s->orig_bio);
@@ -740,7 +779,7 @@ 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 +799,12 @@ 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 +818,8 @@ 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;
@@ -822,7 +863,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
cache_bio->bi_private = &s->cl;
bch_bio_map(cache_bio, NULL);
- if (bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
+ if (bch_bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
goto out_put;
if (reada)
@@ -892,7 +933,7 @@ 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;
@@ -955,6 +996,7 @@ static blk_qc_t cached_dev_make_request(struct request_queue *q,
struct cached_dev *dc = container_of(d, struct cached_dev, disk);
int rw = bio_data_dir(bio);
+ atomic_set(&dc->backing_idle, 0);
generic_start_io_acct(q, rw, bio_sectors(bio), &d->disk->part0);
bio_set_dev(bio, dc->bdev);
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-18 00:38:43 +0200