bcache: fix crash with incomplete cache set

Change-Id: I6abde52afe917633480caaf4e2518f42a816d886

2 files changed, 8 insertions, 0 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index d2ebcf323094..04f7bc28ef83 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -477,9 +477,13 @@ struct gc_stat {
  * CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
  * we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
  * flushing dirty data).
+ *
+ * CACHE_SET_RUNNING means all cache devices have been registered and journal
+ * replay is complete.
  */
 #define CACHE_SET_UNREGISTERING         0
 #define CACHE_SET_STOPPING              1
+#define CACHE_SET_RUNNING               2
 
 struct cache_set {
         struct closure          cl;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 29dd1e8ae19f..72fbaf79b0c8 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1284,6 +1284,9 @@ int bch_flash_dev_create(struct cache_set *c, uint64_t size)
         if (test_bit(CACHE_SET_STOPPING, &c->flags))
                 return -EINTR;
 
+        if (!test_bit(CACHE_SET_RUNNING, &c->flags))
+                return -EPERM;
+
         u = uuid_find_empty(c);
         if (!u) {
                 pr_err("Can't create volume, no room for UUID");
@@ -1706,6 +1709,7 @@ static void run_cache_set(struct cache_set *c)
 
         flash_devs_run(c);
 
+        set_bit(CACHE_SET_RUNNING, &c->flags);
         return;
 err:
         closure_sync(&cl);