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Commit bf0a628a authored by Nicholas Swenson's avatar Nicholas Swenson Committed by Kent Overstreet
Browse files

bcache: fix for gc and writeback race 



Garbage collector needs to check keys in the writeback keybuf to
make sure it's not invalidating buckets to which the writeback
keys point to.

Signed-off-by: default avatarNicholas Swenson <nks@daterainc.com>
Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
parent 981aa8c0

drivers/md/bcache/btree.c

+22 −0
Original line number Diff line number Diff line
@@ -1561,6 +1561,28 @@ size_t bch_btree_gc_finish(struct cache_set *c) 
		SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),

			    GC_MARK_METADATA);



	/* don't reclaim buckets to which writeback keys point */

	rcu_read_lock();

	for (i = 0; i < c->nr_uuids; i++) {

		struct bcache_device *d = c->devices[i];

		struct cached_dev *dc;

		struct keybuf_key *w, *n;

		unsigned j;



		if (!d || UUID_FLASH_ONLY(&c->uuids[i]))

			continue;

		dc = container_of(d, struct cached_dev, disk);



		spin_lock(&dc->writeback_keys.lock);

		rbtree_postorder_for_each_entry_safe(w, n,

					&dc->writeback_keys.keys, node)

			for (j = 0; j < KEY_PTRS(&w->key); j++)

				SET_GC_MARK(PTR_BUCKET(c, &w->key, j),

					    GC_MARK_DIRTY);

		spin_unlock(&dc->writeback_keys.lock);

	}

	rcu_read_unlock();



	for_each_cache(ca, c, i) {

		uint64_t *i;