Commit 70023da2 authored Apr 17, 2013 by Stefan Behrens Committed by Josef Bacik May 06, 2013

Btrfs: clear received_uuid field for new writable snapshots



For created snapshots, the full root_item is copied from the source
root and afterwards selectively modified. The current code forgets
to clear the field received_uuid. The only problem is that it is
confusing when you look at it with 'btrfs subv list', since for
writable snapshots, the contents of the snapshot can be completely
unrelated to the previously received snapshot.
The receiver ignores such snapshots anyway because he also checks
the field stransid in the root_item and that value used to be reset
to zero for all created snapshots.

This commit changes two things:
- clear the received_uuid field for new writable snapshots.
- don't clear the send/receive related information like the stransid
  for read-only snapshots (which makes them useable as a parent for
  the automatic selection of parents in the receive code).

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

parent b8d7f3ac

fs/btrfs/transaction.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -1169,13 +1169,17 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
		memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
		memcpy(new_root_item->parent_uuid, root->root_item.uuid,
		BTRFS_UUID_SIZE);
		new_root_item->otime.sec = cpu_to_le64(cur_time.tv_sec);
		new_root_item->otime.nsec = cpu_to_le32(cur_time.tv_nsec);
		btrfs_set_root_otransid(new_root_item, trans->transid);
		if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
		memset(new_root_item->received_uuid, 0,
		sizeof(new_root_item->received_uuid));
		memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
		memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
		btrfs_set_root_stransid(new_root_item, 0);
		btrfs_set_root_rtransid(new_root_item, 0);
		}
		new_root_item->otime.sec = cpu_to_le64(cur_time.tv_sec);
		new_root_item->otime.nsec = cpu_to_le32(cur_time.tv_nsec);
		btrfs_set_root_otransid(new_root_item, trans->transid);

		old = btrfs_lock_root_node(root);
		ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);

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