When we add a device to the RO mounted seed device, it becomes a RW sprout FS. The following steps are used to hold the seed and sprout fs_devices. (first two steps are not mandatory for the sprouting, they are there to ensure the seed device remains in the scanned state) . Clone the (mounted) fs_devices, lets call it as old_devices . Now add old_devices to fs_uuids (yeah, there is duplicate fsid in the list, as we are under uuid_mutex so its fine).
. Alloc a new fs_devices, lets call it as seed_devices . Copy fs_devices into the seed_devices . Move fs_devices::devices into seed_devices::devices . Bring seed_devices to under fs_devices::seed (fs_devices->seed = seed_devices) . Assign a new FSID to the fs_devices and add the new writable device to the fs_devices. This patch makes the following changes.. As we clone fs_devices to make sure the device remains scanned after the sprouting. So use the btrfs_scan_one_device() code instead. And do it at the end of the sprouting. Signed-off-by: Anand Jain <anand.j...@oracle.com> --- fs/btrfs/volumes.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b63aae267ebe..5bfc3feb715a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2266,7 +2266,7 @@ int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid, static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) { struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; - struct btrfs_fs_devices *old_devices; + struct btrfs_fs_devices *old_fs_devices; struct btrfs_fs_devices *seed_devices; struct btrfs_super_block *disk_super = fs_info->super_copy; struct btrfs_device *device; @@ -2280,14 +2280,6 @@ static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) if (IS_ERR(seed_devices)) return PTR_ERR(seed_devices); - old_devices = clone_fs_devices(fs_devices); - if (IS_ERR(old_devices)) { - kfree(seed_devices); - return PTR_ERR(old_devices); - } - - list_add(&old_devices->fs_list, &fs_uuids); - memcpy(seed_devices, fs_devices, sizeof(*seed_devices)); seed_devices->opened = 1; INIT_LIST_HEAD(&seed_devices->devices); @@ -2320,6 +2312,17 @@ static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) ~BTRFS_SUPER_FLAG_SEEDING; btrfs_set_super_flags(disk_super, super_flags); + /* + * As the above code hijacked the original seed fs_devices, now + * create a new one for the original seed FSID. + */ + list_for_each_entry(device, &fs_devices->seed->devices, dev_list) { + if (!device->name) + continue; + btrfs_scan_one_device(device->name->str, FMODE_READ, + fs_info->bdev_holder, &old_fs_devices); + } + return 0; } -- 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html