This got added 14 years ago in 324ae4df00fd ("Btrfs: Add block group pinned accounting back")
but it was not ever used. Subsequently its usage got gradually removed
in  8790d502e440 ("Btrfs: Add support for mirroring across drives") and
11833d66be94 ("Btrfs: improve async block group caching"). Let's remove
it for good!

Signed-off-by: Nikolay Borisov <redacted>
---
 fs/btrfs/ctree.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d7ef4d7d2c1a..e5e53e592d4f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h

@@ -823,8 +823,6 @@ struct btrfs_fs_info {
 	struct kobject *space_info_kobj;
 	struct kobject *qgroups_kobj;
 
-	u64 total_pinned;
-
 	/* used to keep from writing metadata until there is a nice batch */
 	struct percpu_counter dirty_metadata_bytes;
 	struct percpu_counter delalloc_bytes;