From f62c302e6dfe7bb03b35157e1c1b7cdaeabd54f9 Mon Sep 17 00:00:00 2001
From: Anand Jain <anand.jain@oracle.com>
Date: Wed, 24 May 2023 20:02:38 +0800
Subject: [PATCH] btrfs: add comment about metadata_uuid in btrfs_fs_devices
Add comment about metadata_uuid in btrfs_fs_devices.
No functional change.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/volumes.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 236ae696c9841..24f30542ef7c8 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -280,7 +280,19 @@ enum btrfs_read_policy {
struct btrfs_fs_devices {
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
+
+ /*
+ * UUID written into the btree blocks:
+ *
+ * - If metadata_uuid != fsid then super block must have
+ * BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag set.
+ *
+ * - Following shall be true at all times:
+ * - metadata_uuid == btrfs_header::fsid
+ * - metadata_uuid == btrfs_dev_item::fsid
+ */
u8 metadata_uuid[BTRFS_FSID_SIZE];
+
struct list_head fs_list;
/*