From 20185bb9c399a31ba2b509807c41d77ff62a52aa Mon Sep 17 00:00:00 2001
From: hyche <cvghy116@gmail.com>
Date: Tue, 29 Aug 2017 02:10:11 +0700
Subject: [PATCH] BTRFS: Implement RemoveEntries() for BTree that will remove
 consecutive items and its data.

Signed-off-by: Augustin Cavalier <waddlesplash@gmail.com>
---
 src/add-ons/kernel/file_systems/btrfs/BTree.cpp | 37 +++++++++++++++++++++++++
 src/add-ons/kernel/file_systems/btrfs/BTree.h   |  3 ++
 2 files changed, 40 insertions(+)

diff --git a/src/add-ons/kernel/file_systems/btrfs/BTree.cpp b/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
index 46325a6858..e5f3797323 100644
--- a/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
+++ b/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
@@ -780,6 +780,43 @@ BTree::InsertEntries(Transaction& transaction, Path* path,
 }
 
 
+/* Like MakeEntries, but here we remove entries instead.
+ * Removed data stored in _data
+ * May merge those functions into one.
+ */
+status_t
+BTree::RemoveEntries(Transaction& transaction, Path* path,
+	const btrfs_key& startKey, void** _data, int num)
+{
+	TRACE("BTree::RemoveEntries() num %i key (% " B_PRIu64 " %" B_PRIu8 " %"
+		B_PRIu64 ")\n", num, startKey.ObjectID(), startKey.Type(),
+		startKey.Offset());
+
+	status_t status = Traverse(BTREE_EXACT, path, startKey);
+	if (status < B_OK)
+		return status;
+
+	int slot = status;
+	int length = -sizeof(btrfs_entry) * num;
+	for (int i = 0; i < num; i++) {
+		uint32 itemSize;
+		path->GetEntry(slot + i, NULL, &_data[i], &itemSize);
+		length -= itemSize;
+	}
+
+	status = path->InternalCopy(transaction, 1);
+	if (status != B_OK)
+		return status;
+
+	status = path->CopyOnWrite(transaction, 0, slot, num, length);
+	if (status == B_DIRECTORY_NOT_EMPTY) {
+		// TODO: merge node or push data
+	}
+
+	return status;
+}
+
+
 status_t
 BTree::PreviousLeaf(Path* path) const
 {
diff --git a/src/add-ons/kernel/file_systems/btrfs/BTree.h b/src/add-ons/kernel/file_systems/btrfs/BTree.h
index 839681da4a..1da3561417 100644
--- a/src/add-ons/kernel/file_systems/btrfs/BTree.h
+++ b/src/add-ons/kernel/file_systems/btrfs/BTree.h
@@ -78,6 +78,9 @@ public:
 			status_t			InsertEntries(Transaction& transaction,
 									Path* path, btrfs_entry* entries,
 									void** data, int num);
+			status_t			RemoveEntries(Transaction& transaction,
+									Path* path, const btrfs_key& startKey,
+									void** _data, int num);
 
 			Volume*				SystemVolume() const { return fVolume; }
 			status_t			SetRoot(off_t logical, fsblock_t* block);
-- 
2.11.4.GIT