From 1152651a081720ef6a8c76bb7da676e8c900ac30 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Thu, 17 Jul 2014 12:39:01 -0700 Subject: btrfs: qgroup: account shared subtrees during snapshot delete During its tree walk, btrfs_drop_snapshot() will skip any shared subtrees it encounters. This is incorrect when we have qgroups turned on as those subtrees need to have their contents accounted. In particular, the case we're concerned with is when removing our snapshot root leaves the subtree with only one root reference. In those cases we need to find the last remaining root and add each extent in the subtree to the corresponding qgroup exclusive counts. This patch implements the shared subtree walk and a new qgroup operation, BTRFS_QGROUP_OPER_SUB_SUBTREE. When an operation of this type is encountered during qgroup accounting, we search for any root references to that extent and in the case that we find only one reference left, we go ahead and do the math on it's exclusive counts. Signed-off-by: Mark Fasheh Reviewed-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/qgroup.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/qgroup.h') diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h index 5952ff1fbd7a..18cc68ca3090 100644 --- a/fs/btrfs/qgroup.h +++ b/fs/btrfs/qgroup.h @@ -44,6 +44,7 @@ enum btrfs_qgroup_operation_type { BTRFS_QGROUP_OPER_ADD_SHARED, BTRFS_QGROUP_OPER_SUB_EXCL, BTRFS_QGROUP_OPER_SUB_SHARED, + BTRFS_QGROUP_OPER_SUB_SUBTREE, }; struct btrfs_qgroup_operation { -- cgit v1.2.1