[PATCH 3.14 097/110] Btrfs: set right total device count for seeding support

Greg Kroah-Hartman
2014-06-28T18:30:57Z

From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>

commit 298658414a2f0bea1f05a81876a45c1cd96aa2e0 upstream.

Seeding device support allows us to create a new filesystem
based on existed filesystem.

However newly created filesystem's @total_devices should include seed
devices. This patch fix the following problem:

# mkfs.btrfs -f /dev/sdb
# btrfstune -S 1 /dev/sdb
# mount /dev/sdb /mnt
# btrfs device add -f /dev/sdc /mnt --->fs_devices->total_devices = 1
# umount /mnt
# mount /dev/sdc /mnt --->fs_devices->total_devices = 2

This is because we record right @total_devices in superblock, but
@fs_devices->total_devices is reset to be 0 in btrfs_prepare_sprout().

Fix this problem by not resetting @fs_devices->total_devices.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/volumes.c | 1 -
1 file changed, 1 deletion(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1889,7 +1889,6 @@ static int btrfs_prepare_sprout(struct b
fs_devices->seeding = 0;
fs_devices->num_devices = 0;
fs_devices->open_devices = 0;
- fs_devices->total_devices = 0;
fs_devices->seed = seed_devices;

generate_random_uuid(fs_devices->fsid);