bcache: fix for gc and writeback race
authorNicholas Swenson <nks@daterainc.com>
Wed, 27 Nov 2013 03:14:23 +0000 (19:14 -0800)
committerKent Overstreet <kmo@daterainc.com>
Mon, 16 Dec 2013 22:22:58 +0000 (14:22 -0800)
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: Nicholas Swenson <nks@daterainc.com>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
drivers/md/bcache/btree.c

index c36745e5986ab2746582bf464120041197df0096..31bb53fcc67a40806cf73659a596f98297d36128 100644 (file)
@@ -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;