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bcache: Refactor journalling flow control

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Making things less asynchronous that don't need to be - bch_journal()
only has to block when the journal or journal entry is full, which is
emphatically not a fast path. So make it a normal function that just
returns when it finishes, to make the code and control flow easier to
follow.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
这个提交包含在：
Kent Overstreet
2013-10-24 17:07:04 -07:00
父节点 cdd972b164
当前提交 a34a8bfd4e
共修改 7 个文件，包含 210 行新增和 182 行删除
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162
drivers/md/bcache/request.c
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@@ -25,6 +25,8 @@
struct kmem_cache *bch_search_cache;
static void bch_data_insert_start(struct closure *);
/* Cgroup interface */
#ifdef CONFIG_CGROUP_BCACHE
@@ -211,31 +213,42 @@ static void bio_csum(struct bio *bio, struct bkey *k)
/* Insert data into cache */
static void bio_invalidate(struct closure *cl)
static void bch_data_insert_keys(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
struct bio *bio = op->cache_bio;
struct search *s = container_of(op, struct search, op);
pr_debug("invalidating %i sectors from %llu",
bio_sectors(bio), (uint64_t) bio->bi_sector);
/*
* If we're looping, might already be waiting on
* another journal write - can't wait on more than one journal write at
* a time
*
* XXX: this looks wrong
*/
#if 0
while (atomic_read(&s->cl.remaining) & CLOSURE_WAITING)
closure_sync(&s->cl);
#endif
while (bio_sectors(bio)) {
unsigned len = min(bio_sectors(bio), 1U << 14);
if (s->write)
op->journal = bch_journal(op->c, &op->keys,
op->flush_journal
? &s->cl : NULL);
if (bch_keylist_realloc(&op->keys, 0, op->c))
goto out;
bio->bi_sector += len;
bio->bi_size -= len << 9;
bch_keylist_add(&op->keys,
&KEY(op->inode, bio->bi_sector, len));
if (bch_btree_insert(op, op->c, &op->keys)) {
s->error = -ENOMEM;
op->insert_data_done = true;
}
op->insert_data_done = true;
bio_put(bio);
out:
continue_at(cl, bch_journal, bcache_wq);
if (op->journal)
atomic_dec_bug(op->journal);
op->journal = NULL;
if (!op->insert_data_done)
continue_at(cl, bch_data_insert_start, bcache_wq);
bch_keylist_free(&op->keys);
closure_return(cl);
}
struct open_bucket {
@@ -423,7 +436,34 @@ static bool bch_alloc_sectors(struct bkey *k, unsigned sectors,
return true;
}
static void bch_insert_data_error(struct closure *cl)
static void bch_data_invalidate(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
struct bio *bio = op->cache_bio;
pr_debug("invalidating %i sectors from %llu",
bio_sectors(bio), (uint64_t) bio->bi_sector);
while (bio_sectors(bio)) {
unsigned len = min(bio_sectors(bio), 1U << 14);
if (bch_keylist_realloc(&op->keys, 0, op->c))
goto out;
bio->bi_sector += len;
bio->bi_size -= len << 9;
bch_keylist_add(&op->keys, &KEY(op->inode,
bio->bi_sector, len));
}
op->insert_data_done = true;
bio_put(bio);
out:
continue_at(cl, bch_data_insert_keys, bcache_wq);
}
static void bch_data_insert_error(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
@@ -450,10 +490,10 @@ static void bch_insert_data_error(struct closure *cl)
op->keys.top = dst;
bch_journal(cl);
bch_data_insert_keys(cl);
}
static void bch_insert_data_endio(struct bio *bio, int error)
static void bch_data_insert_endio(struct bio *bio, int error)
{
struct closure *cl = bio->bi_private;
struct btree_op *op = container_of(cl, struct btree_op, cl);
@@ -464,7 +504,7 @@ static void bch_insert_data_endio(struct bio *bio, int error)
if (s->writeback)
s->error = error;
else if (s->write)
set_closure_fn(cl, bch_insert_data_error, bcache_wq);
set_closure_fn(cl, bch_data_insert_error, bcache_wq);
else
set_closure_fn(cl, NULL, NULL);
}
@@ -472,14 +512,14 @@ static void bch_insert_data_endio(struct bio *bio, int error)
bch_bbio_endio(op->c, bio, error, "writing data to cache");
}
static void bch_insert_data_loop(struct closure *cl)
static void bch_data_insert_start(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
struct search *s = container_of(op, struct search, op);
struct bio *bio = op->cache_bio, *n;
if (op->bypass)
return bio_invalidate(cl);
return bch_data_invalidate(cl);
if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) {
set_gc_sectors(op->c);
@@ -502,7 +542,7 @@ static void bch_insert_data_loop(struct closure *cl)
if (bch_keylist_realloc(&op->keys,
1 + (op->csum ? 1 : 0),
op->c))
continue_at(cl, bch_journal, bcache_wq);
continue_at(cl, bch_data_insert_keys, bcache_wq);
k = op->keys.top;
bkey_init(k);
@@ -514,7 +554,7 @@ static void bch_insert_data_loop(struct closure *cl)
n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
n->bi_end_io = bch_insert_data_endio;
n->bi_end_io = bch_data_insert_endio;
n->bi_private = cl;
if (s->writeback) {
@@ -537,7 +577,7 @@ static void bch_insert_data_loop(struct closure *cl)
} while (n != bio);
op->insert_data_done = true;
continue_at(cl, bch_journal, bcache_wq);
continue_at(cl, bch_data_insert_keys, bcache_wq);
err:
/* bch_alloc_sectors() blocks if s->writeback = true */
BUG_ON(s->writeback);
@@ -556,7 +596,7 @@ err:
* rest of the write.
*/
op->bypass = true;
return bio_invalidate(cl);
return bch_data_invalidate(cl);
} else {
/*
* From a cache miss, we can just insert the keys for the data
@@ -566,14 +606,14 @@ err:
bio_put(bio);
if (!bch_keylist_empty(&op->keys))
continue_at(cl, bch_journal, bcache_wq);
continue_at(cl, bch_data_insert_keys, bcache_wq);
else
closure_return(cl);
}
}
/**
* bch_insert_data - stick some data in the cache
* bch_data_insert - stick some data in the cache
*
* This is the starting point for any data to end up in a cache device; it could
* be from a normal write, or a writeback write, or a write to a flash only
@@ -591,30 +631,13 @@ err:
* If op->bypass is true, instead of inserting the data it invalidates the
* region of the cache represented by op->cache_bio and op->inode.
*/
void bch_insert_data(struct closure *cl)
void bch_data_insert(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
bch_keylist_init(&op->keys);
bio_get(op->cache_bio);
bch_insert_data_loop(cl);
}
void bch_btree_insert_async(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
struct search *s = container_of(op, struct search, op);
if (bch_btree_insert(op, op->c, &op->keys)) {
s->error = -ENOMEM;
op->insert_data_done = true;
}
if (op->insert_data_done) {
bch_keylist_free(&op->keys);
closure_return(cl);
} else
continue_at(cl, bch_insert_data_loop, bcache_wq);
bch_data_insert_start(cl);
}
/* Common code for the make_request functions */
@@ -969,7 +992,7 @@ static void cached_dev_read_done(struct closure *cl)
if (s->op.cache_bio &&
!test_bit(CACHE_SET_STOPPING, &s->op.c->flags)) {
s->op.type = BTREE_REPLACE;
closure_call(&s->op.cl, bch_insert_data, NULL, cl);
closure_call(&s->op.cl, bch_data_insert, NULL, cl);
}
continue_at(cl, cached_dev_cache_miss_done, NULL);
@@ -1147,13 +1170,13 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s)
closure_bio_submit(bio, cl, s->d);
}
closure_call(&s->op.cl, bch_insert_data, NULL, cl);
closure_call(&s->op.cl, bch_data_insert, NULL, cl);
continue_at(cl, cached_dev_write_complete, NULL);
}
static void cached_dev_nodata(struct cached_dev *dc, struct search *s)
static void cached_dev_nodata(struct closure *cl)
{
struct closure *cl = &s->cl;
struct search *s = container_of(cl, struct search, cl);
struct bio *bio = &s->bio.bio;
if (s->op.flush_journal)
@@ -1186,9 +1209,15 @@ static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
s = search_alloc(bio, d);
trace_bcache_request_start(s, bio);
if (!bio->bi_size)
cached_dev_nodata(dc, s);
else {
if (!bio->bi_size) {
/*
* can't call bch_journal_meta from under
* generic_make_request
*/
continue_at_nobarrier(&s->cl,
cached_dev_nodata,
bcache_wq);
} else {
s->op.bypass = check_should_bypass(dc, s);
if (rw)
@@ -1275,6 +1304,16 @@ static int flash_dev_cache_miss(struct btree *b, struct search *s,
return 0;
}
static void flash_dev_nodata(struct closure *cl)
{
struct search *s = container_of(cl, struct search, cl);
if (s->op.flush_journal)
bch_journal_meta(s->op.c, cl);
continue_at(cl, search_free, NULL);
}
static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
{
struct search *s;
@@ -1294,8 +1333,13 @@ static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
trace_bcache_request_start(s, bio);
if (!bio->bi_size) {
if (s->op.flush_journal)
bch_journal_meta(s->op.c, cl);
/*
* can't call bch_journal_meta from under
* generic_make_request
*/
continue_at_nobarrier(&s->cl,
flash_dev_nodata,
bcache_wq);
} else if (rw) {
bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys,
&KEY(d->id, bio->bi_sector, 0),
@@ -1305,7 +1349,7 @@ static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
s->writeback = true;
s->op.cache_bio = bio;
closure_call(&s->op.cl, bch_insert_data, NULL, cl);
closure_call(&s->op.cl, bch_data_insert, NULL, cl);
} else {
closure_call(&s->op.cl, btree_read_async, NULL, cl);
}