Commit 78b77bf8 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcache: Btree verify code improvements 



Used this fixed code to find and fix the bug fixed by
a4d885097b0ac0cd1337f171f2d4b83e946094d4.

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
parent 88b9f8c4

drivers/md/bcache/bcache.h

+1 −0
Original line number Diff line number Diff line
@@ -629,6 +629,7 @@ struct cache_set { 


#ifdef CONFIG_BCACHE_DEBUG

	struct btree		*verify_data;

	struct bset		*verify_ondisk;

	struct mutex		verify_lock;

#endif

drivers/md/bcache/bset.c

+0 −3
Original line number Diff line number Diff line
@@ -1060,9 +1060,6 @@ static void __btree_sort(struct btree *b, struct btree_iter *iter, 
	btree_mergesort(b, out, iter, fixup, remove_stale);

	b->nsets = start;



	if (!fixup && !start && b->written)

		bch_btree_verify(b, out);



	if (!start && order == b->page_order) {

		/*

		 * Our temporary buffer is the same size as the btree node's

drivers/md/bcache/btree.c

+14 −2
Original line number Diff line number Diff line
@@ -203,7 +203,7 @@ static uint64_t btree_csum_set(struct btree *b, struct bset *i) 
	return crc ^ 0xffffffffffffffffULL;

}



static void bch_btree_node_read_done(struct btree *b)

void bch_btree_node_read_done(struct btree *b)

{

	const char *err = "bad btree header";

	struct bset *i = b->sets[0].data;
@@ -290,7 +290,7 @@ static void btree_node_read_endio(struct bio *bio, int error) 
	closure_put(cl);

}



void bch_btree_node_read(struct btree *b)

static void bch_btree_node_read(struct btree *b)

{

	uint64_t start_time = local_clock();

	struct closure cl;
@@ -478,6 +478,13 @@ void bch_btree_node_write(struct btree *b, struct closure *parent) 


	bch_btree_sort_lazy(b);



	/*

	 * do verify if there was more than one set initially (i.e. we did a

	 * sort) and we sorted down to a single set:

	 */

	if (i != b->sets->data && !b->nsets)

		bch_btree_verify(b);



	if (b->written < btree_blocks(b))

		bch_bset_init_next(b);

}
@@ -782,6 +789,8 @@ void bch_btree_cache_free(struct cache_set *c) 
#ifdef CONFIG_BCACHE_DEBUG

	if (c->verify_data)

		list_move(&c->verify_data->list, &c->btree_cache);



	free_pages((unsigned long) c->verify_ondisk, ilog2(bucket_pages(c)));

#endif



	list_splice(&c->btree_cache_freeable,
@@ -822,6 +831,9 @@ int bch_btree_cache_alloc(struct cache_set *c) 
#ifdef CONFIG_BCACHE_DEBUG

	mutex_init(&c->verify_lock);



	c->verify_ondisk = (void *)

		__get_free_pages(GFP_KERNEL, ilog2(bucket_pages(c)));



	c->verify_data = mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);



	if (c->verify_data &&

drivers/md/bcache/btree.h

+1 −1
Original line number Diff line number Diff line
@@ -292,7 +292,7 @@ static inline void rw_unlock(bool w, struct btree *b) 
	(w ? up_write : up_read)(&b->lock);

}



void bch_btree_node_read(struct btree *);

void bch_btree_node_read_done(struct btree *);

void bch_btree_node_write(struct btree *, struct closure *);



void bch_btree_set_root(struct btree *);

drivers/md/bcache/debug.c

+65 −32
Original line number Diff line number Diff line
@@ -53,17 +53,17 @@ int bch_bkey_to_text(char *buf, size_t size, const struct bkey *k) 


#define p(...)	(out += scnprintf(out, end - out, __VA_ARGS__))



	p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_OFFSET(k), KEY_SIZE(k));



	if (KEY_PTRS(k))

		while (1) {

			p("%llu:%llu gen %llu",

			  PTR_DEV(k, i), PTR_OFFSET(k, i), PTR_GEN(k, i));



			if (++i == KEY_PTRS(k))

				break;

	p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_START(k), KEY_SIZE(k));



	for (i = 0; i < KEY_PTRS(k); i++) {

		if (i)

			p(", ");



		if (PTR_DEV(k, i) == PTR_CHECK_DEV)

			p("check dev");

		else

			p("%llu:%llu gen %llu", PTR_DEV(k, i),

			  PTR_OFFSET(k, i), PTR_GEN(k, i));

	}



	p("]");
@@ -78,7 +78,7 @@ int bch_bkey_to_text(char *buf, size_t size, const struct bkey *k) 


#ifdef CONFIG_BCACHE_DEBUG



static void dump_bset(struct btree *b, struct bset *i)

static void dump_bset(struct btree *b, struct bset *i, unsigned set)

{

	struct bkey *k, *next;

	unsigned j;
@@ -88,7 +88,7 @@ static void dump_bset(struct btree *b, struct bset *i) 
		next = bkey_next(k);



		bch_bkey_to_text(buf, sizeof(buf), k);

		printk(KERN_ERR "block %u key %zi/%u: %s", bset_block_offset(b, i),

		printk(KERN_ERR "b %u k %zi/%u: %s", set,

		       (uint64_t *) k - i->d, i->keys, buf);



		for (j = 0; j < KEY_PTRS(k); j++) {
@@ -114,50 +114,83 @@ static void bch_dump_bucket(struct btree *b) 


	console_lock();

	for (i = 0; i <= b->nsets; i++)

		dump_bset(b, b->sets[i].data);

		dump_bset(b, b->sets[i].data,

			  bset_block_offset(b, b->sets[i].data));

	console_unlock();

}



void bch_btree_verify(struct btree *b, struct bset *new)

#define for_each_written_bset(b, start, i)				\

	for (i = (start);						\

	     (void *) i < (void *) (start) + (KEY_SIZE(&b->key) << 9) &&\

	     i->seq == (start)->seq;					\

	     i = (void *) i + set_blocks(i, b->c) * block_bytes(b->c))



void bch_btree_verify(struct btree *b)

{

	struct btree *v = b->c->verify_data;

	struct closure cl;

	closure_init_stack(&cl);

	struct bset *ondisk, *sorted, *inmemory;

	struct bio *bio;



	if (!b->c->verify)

	if (!b->c->verify || !b->c->verify_ondisk)

		return;



	down(&b->io_mutex);

	mutex_lock(&b->c->verify_lock);



	ondisk = b->c->verify_ondisk;

	sorted = b->c->verify_data->sets->data;

	inmemory = b->sets->data;



	bkey_copy(&v->key, &b->key);

	v->written = 0;

	v->level = b->level;



	bch_btree_node_read(v);

	bio = bch_bbio_alloc(b->c);

	bio->bi_bdev		= PTR_CACHE(b->c, &b->key, 0)->bdev;

	bio->bi_iter.bi_sector	= PTR_OFFSET(&b->key, 0);

	bio->bi_iter.bi_size	= KEY_SIZE(&v->key) << 9;

	bch_bio_map(bio, sorted);



	submit_bio_wait(REQ_META|READ_SYNC, bio);

	bch_bbio_free(bio, b->c);



	memcpy(ondisk, sorted, KEY_SIZE(&v->key) << 9);



	if (new->keys != v->sets[0].data->keys ||

	    memcmp(new->start,

		   v->sets[0].data->start,

		   (void *) end(new) - (void *) new->start)) {

		unsigned i, j;

	bch_btree_node_read_done(v);

	sorted = v->sets->data;



	if (inmemory->keys != sorted->keys ||

	    memcmp(inmemory->start,

		   sorted->start,

		   (void *) end(inmemory) - (void *) inmemory->start)) {

		struct bset *i;

		unsigned j;



		console_lock();



		printk(KERN_ERR "*** original memory node:\n");

		for (i = 0; i <= b->nsets; i++)

			dump_bset(b, b->sets[i].data);

		printk(KERN_ERR "*** in memory:\n");

		dump_bset(b, inmemory, 0);



		printk(KERN_ERR "*** sorted memory node:\n");

		dump_bset(b, new);

		printk(KERN_ERR "*** read back in:\n");

		dump_bset(v, sorted, 0);



		printk(KERN_ERR "*** on disk node:\n");

		dump_bset(v, v->sets[0].data);

		for_each_written_bset(b, ondisk, i) {

			unsigned block = ((void *) i - (void *) ondisk) /

				block_bytes(b->c);



		for (j = 0; j < new->keys; j++)

			if (new->d[j] != v->sets[0].data->d[j])

			printk(KERN_ERR "*** on disk block %u:\n", block);

			dump_bset(b, i, block);

		}



		printk(KERN_ERR "*** block %zu not written\n",

		       ((void *) i - (void *) ondisk) / block_bytes(b->c));



		for (j = 0; j < inmemory->keys; j++)

			if (inmemory->d[j] != sorted->d[j])

				break;



		printk(KERN_ERR "b->written %u\n", b->written);



		console_unlock();

		panic("verify failed at %u\n", j);

	}