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 8450bcfed4cb..c6f3f0dfbabe 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2179,7 +2179,7 @@ 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;
@@ -2193,14 +2193,6 @@ 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);
@@ -2233,6 +2225,17 @@ 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
