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: Nicholas Swenson <nks@daterainc.com>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index c36745e..31bb53f 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1561,6 +1561,28 @@
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;