From d1a63002829a4d8014de20dc141b404cc808405e Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 30 Oct 2018 16:43:26 +0200 Subject: btrfs: add members to fs_devices to track fsid changes In order to gracefully handle split-brain scenario during fsid change (which are very unlikely, yet possible), two more pieces of information will be necessary: 1. The highest generation number among all devices registered to a particular btrfs_fs_devices 2. A boolean flag whether a given btrfs_fs_devices was created by a device which had the FSID_CHANGING_V2 flag set. This is a preparatory patch and just introduces the variables as well as code which sets them, their actual use is going to happen in a later patch. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/btrfs/volumes.h') diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index bdee4b60e0ba..1d936ce282c3 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -211,6 +211,7 @@ BTRFS_DEVICE_GETSET_FUNCS(bytes_used); struct btrfs_fs_devices { u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */ u8 metadata_uuid[BTRFS_FSID_SIZE]; + bool fsid_change; struct list_head fs_list; u64 num_devices; @@ -219,6 +220,10 @@ struct btrfs_fs_devices { u64 missing_devices; u64 total_rw_bytes; u64 total_devices; + + /* Highest generation number of seen devices */ + u64 latest_generation; + struct block_device *latest_bdev; /* all of the devices in the FS, protected by a mutex -- cgit v1.2.3-59-g8ed1b