From 84bc447cae639842c6c3b7fe2d28bd52e2384eab Mon Sep 17 00:00:00 2001
From: hyche <cvghy116@gmail.com>
Date: Tue, 29 Aug 2017 02:07:52 +0700
Subject: [PATCH] BTRFS: Implement InsertEntries() that will insert consecutive
 items and its data.

Signed-off-by: Augustin Cavalier <waddlesplash@gmail.com>
---
 src/add-ons/kernel/file_systems/btrfs/BTree.cpp | 78 +++++++++++++++++++++++++
 src/add-ons/kernel/file_systems/btrfs/BTree.h   |  7 +++
 2 files changed, 85 insertions(+)

diff --git a/src/add-ons/kernel/file_systems/btrfs/BTree.cpp b/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
index 39e1e9475f..46325a6858 100644
--- a/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
+++ b/src/add-ons/kernel/file_systems/btrfs/BTree.cpp
@@ -420,6 +420,18 @@ BTree::Path::GetEntry(int slot, btrfs_key* _key, void** _value, uint32* _size,
 }
 
 
+status_t
+BTree::Path::SetEntry(int slot, const btrfs_entry& entry, void* value)
+{
+	if (slot < 0)
+		return B_ENTRY_NOT_FOUND;
+
+	memcpy(fNodes[0]->Item(slot), &entry, sizeof(btrfs_entry));
+	memcpy(fNodes[0]->ItemData(slot), value, entry.Size());
+	return B_OK;
+}
+
+
 /*
  * Allocate and copy block and do all the changes that it can.
  * for now, we only copy-on-write tree block,
@@ -702,6 +714,72 @@ BTree::FindExact(Path* path, btrfs_key& key, void** _value, uint32* _size,
 }
 
 
+/*
+ * Insert "num" of consecutive empty entries start with slot of "startKey"
+ * if successful return the starting slot, otherwise return error code.
+ */
+status_t
+BTree::MakeEntries(Transaction& transaction, Path* path,
+	const btrfs_key& startKey, int num, int length)
+{
+	TRACE("BTree::MakeEntries() num %i key (% " B_PRIu64 " %" B_PRIu8 " %"
+		B_PRIu64 ")\n", num, startKey.ObjectID(), startKey.Type(),
+		startKey.Offset());
+
+	status_t status = Traverse(BTREE_FORWARD, path, startKey);
+	if (status < B_OK)
+		return status;
+
+	int slot = status;
+	status = path->InternalCopy(transaction, 1);
+	if (status != B_OK)
+		return status;
+
+	status = path->CopyOnWrite(transaction, 0, slot, num, length);
+	if (status == B_DEVICE_FULL) {
+		// TODO: push data or split node
+		return status;
+	}
+
+	if (status != B_OK)
+		return status;
+	return slot;
+}
+
+
+/* MakeEntries and then fill in them.
+ */
+status_t
+BTree::InsertEntries(Transaction& transaction, Path* path,
+	btrfs_entry* entries, void** data, int num)
+{
+	int totalLength = sizeof(btrfs_entry) * num;
+	for (int i = 0; i < num; i++)
+		totalLength += entries[i].Size();
+
+	status_t slot = MakeEntries(transaction, path, entries[0].key, num,
+		totalLength);
+	if (slot < B_OK)
+		return slot;
+
+	uint32 upperLimit;
+	if (slot > 0) {
+		path->GetEntry(slot - 1, NULL, NULL, NULL, &upperLimit);
+	} else
+		upperLimit = fVolume->BlockSize() - sizeof(btrfs_header);
+
+	TRACE("BTree::InsertEntries() num: %i upper limit %" B_PRIu32 "\n", num,
+		upperLimit);
+	for (int i = 0; i < num; i++) {
+		upperLimit -= entries[i].Size();
+		entries[i].SetOffset(upperLimit);
+		path->SetEntry(slot + i, entries[i], data[i]);
+	}
+
+	return B_OK;
+}
+
+
 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 57ba503662..839681da4a 100644
--- a/src/add-ons/kernel/file_systems/btrfs/BTree.h
+++ b/src/add-ons/kernel/file_systems/btrfs/BTree.h
@@ -72,6 +72,12 @@ public:
 
 			status_t			PreviousLeaf(Path* path) const;
 			status_t			NextLeaf(Path* path) const;
+			status_t			MakeEntries(Transaction& transaction,
+									Path* path, const btrfs_key& startKey,
+									int num, int length);
+			status_t			InsertEntries(Transaction& transaction,
+									Path* path, btrfs_entry* entries,
+									void** data, int num);
 
 			Volume*				SystemVolume() const { return fVolume; }
 			status_t			SetRoot(off_t logical, fsblock_t* block);
@@ -181,6 +187,7 @@ public:
 						uint32* _size = NULL, uint32* _offset = NULL);
 		status_t	GetEntry(int slot, btrfs_key* _key, void** _value,
 						uint32* _size = NULL, uint32* _offset = NULL);
+		status_t	SetEntry(int slot, const btrfs_entry& entry, void* value);
 
 		int			Move(int level, int step);
 
-- 
2.11.4.GIT