btrfs: add assertion helpers for spinning readers

Add helpers for conditional DEBUG build to assert that the extent buffer
spinning_readers constraints are met. Will be used in followup patches.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index a5a3c5118f613b27f39dac8d88a9ee9099b81069..2dd3ae524aa31fd9e2bdf0057978fc1ab9265f21 100644 (file)
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -32,10 +32,23 @@ static void btrfs_assert_no_spinning_writers(struct extent_buffer *eb)
        WARN_ON(atomic_read(&eb->spinning_writers));
 }
 
+static void btrfs_assert_spinning_readers_get(struct extent_buffer *eb)
+{
+       atomic_inc(&eb->spinning_readers);
+}
+
+static void btrfs_assert_spinning_readers_put(struct extent_buffer *eb)
+{
+       WARN_ON(atomic_read(&eb->spinning_readers) == 0);
+       atomic_dec(&eb->spinning_readers);
+}
+
 #else
 static void btrfs_assert_spinning_writers_get(struct extent_buffer *eb) { }
 static void btrfs_assert_spinning_writers_put(struct extent_buffer *eb) { }
 static void btrfs_assert_no_spinning_writers(struct extent_buffer *eb) { }
+static void btrfs_assert_spinning_readers_put(struct extent_buffer *eb) { }
+static void btrfs_assert_spinning_readers_get(struct extent_buffer *eb) { }
 #endif
 
 void btrfs_set_lock_blocking_read(struct extent_buffer *eb)