diff options
| author | Nikolay Borisov <nborisov@suse.com> | 2018-10-30 16:43:26 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-12-17 14:51:38 +0100 |
| commit | d1a63002829a4d8014de20dc141b404cc808405e (patch) | |
| tree | 0734637651debfcf49ac8c20c8711a4924d131bd | |
| parent | fbc6feaec98ac0c6a615bbe9e17c5689a1a84650 (diff) | |
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 <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/volumes.c | 9 | ||||
| -rw-r--r-- | fs/btrfs/volumes.h | 5 |
2 files changed, 13 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 032310dacf77..13bb44194c56 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -792,6 +792,8 @@ static noinline struct btrfs_device *device_list_add(const char *path, u64 devid = btrfs_stack_device_id(&disk_super->dev_item); bool has_metadata_uuid = (btrfs_super_incompat_flags(disk_super) & BTRFS_FEATURE_INCOMPAT_METADATA_UUID); + bool fsid_change_in_progress = (btrfs_super_flags(disk_super) & + BTRFS_SUPER_FLAG_CHANGING_FSID_V2); if (has_metadata_uuid) fs_devices = find_fsid(disk_super->fsid, disk_super->metadata_uuid); @@ -805,6 +807,8 @@ static noinline struct btrfs_device *device_list_add(const char *path, else fs_devices = alloc_fs_devices(disk_super->fsid, NULL); + fs_devices->fsid_change = fsid_change_in_progress; + if (IS_ERR(fs_devices)) return ERR_CAST(fs_devices); @@ -940,8 +944,11 @@ static noinline struct btrfs_device *device_list_add(const char *path, * it back. We need it to pick the disk with largest generation * (as above). */ - if (!fs_devices->opened) + if (!fs_devices->opened) { device->generation = found_transid; + fs_devices->latest_generation = max_t(u64, found_transid, + fs_devices->latest_generation); + } fs_devices->total_devices = btrfs_super_num_devices(disk_super); 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 |