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btrfs: documented BTree class (no functional change)

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Change-Id: Ib3d6247bf99fc520ba063c361a7b465224805610
This commit is contained in:
brjhaiku
2019-10-08 19:07:12 +02:00
committed by Adrien Destugues
parent ae24179211
commit b951cbd355
2 changed files with 74 additions and 78 deletions
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src/add-ons/kernel/file_systems/btrfs/BTree.cpp
+2 -75
View File
@@ -51,13 +51,6 @@ BTree::Node::~Node()
}
void
BTree::Node::Keep()
{
fNode = NULL;
}
void
BTree::Node::Unset()
{
@@ -141,13 +134,6 @@ BTree::Node::SearchSlot(const btrfs_key& key, int* slot, btree_traversing type)
}
/*
* calculate used space except the header.
* type is only for leaf node
* type 1: only item space
* type 2: only item data space
* type 3: both type 1 and 2
*/
int
BTree::Node::_CalculateSpace(uint32 from, uint32 to, uint8 type) const
{
@@ -223,14 +209,6 @@ BTree::Node::_SpaceCheck(int length) const
}
/*
* copy node header, items and items data
* length is size to insert/remove
* if node is a internal node, length isnt used
* length = 0: Copy a whole
* length < 0: removing
* length > 0: inserting
*/
status_t
BTree::Node::Copy(const Node* origin, uint32 start, uint32 end, int length)
const
@@ -268,8 +246,6 @@ BTree::Node::Copy(const Node* origin, uint32 start, uint32 end, int length)
}
/* Like copy but here we use memmove on current node.
*/
status_t
BTree::Node::MoveEntries(uint32 start, uint32 end, int length) const
{
@@ -432,15 +408,6 @@ BTree::Path::SetEntry(int slot, const btrfs_entry& entry, void* value)
}
/*
* Allocate and copy block and do all the changes that it can.
* for now, we only copy-on-write tree block,
* file data is "nocow" by default.
*
* o parent o
* | ===> \
* o x o
*/
status_t
BTree::Path::CopyOnWrite(Transaction& transaction, int level, uint32 start,
int num, int length)
@@ -504,22 +471,6 @@ BTree::Path::CopyOnWrite(Transaction& transaction, int level, uint32 start,
}
/* Copy-On-Write all internal nodes start from a specific level.
* level > 0: to root
* level <= 0: to leaf
*
* path cow-path path cow-path
* =================================================
* root cow-root root level < 0
* | | |
* n1 cow-n1 ...______
* | | | \
* n2 cow-n2 n1 cow-n1
* | / | |
* ...____/ n2 cow-n2
* | | |
* leaf level > 0 leaf cow-leaf
*/
status_t
BTree::Path::InternalCopy(Transaction& transaction, int level)
{
@@ -532,6 +483,8 @@ BTree::Path::InternalCopy(Transaction& transaction, int level)
from = level;
to = fTree->RootLevel();
} else {
from = 0;
to = std::abs(level);
}
@@ -616,9 +569,6 @@ btrfs_key::Compare(const btrfs_key& key) const
}
/* Traverse from root to fill in the path along way its finding.
* Return current slot at leaf if successful.
*/
status_t
BTree::Traverse(btree_traversing type, Path* path, const btrfs_key& key)
const
@@ -664,11 +614,6 @@ BTree::Traverse(btree_traversing type, Path* path, const btrfs_key& key)
}
/*! Searches the key in the tree, and stores the allocated found item in
_value, if successful.
Returns B_OK when the key could be found, B_ENTRY_NOT_FOUND if not.
It can also return other errors to indicate that something went wrong.
*/
status_t
BTree::_Find(Path* path, btrfs_key& wanted, void** _value, uint32* _size,
uint32* _offset, btree_traversing type) const
@@ -719,10 +664,6 @@ 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)
@@ -752,8 +693,6 @@ BTree::MakeEntries(Transaction& transaction, Path* path,
}
/* MakeEntries and then fill in them.
*/
status_t
BTree::InsertEntries(Transaction& transaction, Path* path,
btrfs_entry* entries, void** data, int num)
@@ -785,10 +724,6 @@ 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)
@@ -901,9 +836,6 @@ BTree::NextLeaf(Path* path) const
}
/* Set root infomation, to use this function root must be valid and
* exists on disk.
*/
status_t
BTree::SetRoot(off_t logical, fsblock_t* block)
{
@@ -988,8 +920,6 @@ TreeIterator::Rewind(bool inverse)
}
/*! Iterates through the tree in the specified direction.
*/
status_t
TreeIterator::_Traverse(btree_traversing direction)
{
@@ -1003,7 +933,6 @@ TreeIterator::_Traverse(btree_traversing direction)
}
// Like GetEntry in BTree::Path but here we check the type and moving.
status_t
TreeIterator::_GetEntry(btree_traversing type, void** _value, uint32* _size,
uint32* _offset)
@@ -1041,8 +970,6 @@ TreeIterator::_GetEntry(btree_traversing type, void** _value, uint32* _size,
}
/*! just sets the current key in the iterator.
*/
status_t
TreeIterator::Find(const btrfs_key& key)
{
src/add-ons/kernel/file_systems/btrfs/BTree.h
+72 -3
View File
@@ -18,6 +18,7 @@
#define BTRFS_MAX_TREE_DEPTH 8
//! Tree traversal direction status, used by functions manipulating trees
enum btree_traversing {
BTREE_FORWARD = 1,
BTREE_EXACT = 0,
@@ -68,17 +69,30 @@ public:
void** _value, uint32* _size = NULL,
uint32* _offset = NULL) const;
/*! Traverse from the root to fill in the path along the way
* \return Current slot at leaf if successful, error code (out of memory,
* no such entry, unmapped block) otherwise
*/
status_t Traverse(btree_traversing type, Path* path,
const btrfs_key& key) const;
status_t PreviousLeaf(Path* path) const;
status_t NextLeaf(Path* path) const;
/*! Insert consecutive empty entries
* \param num Number of entries to be inserted
* \param startKey Slot to start inserting
* \return Starting slot on success, error code otherwise
*/
status_t MakeEntries(Transaction& transaction,
Path* path, const btrfs_key& startKey,
int num, int length);
//! MakeEntries and fill in them
status_t InsertEntries(Transaction& transaction,
Path* path, btrfs_entry* entries,
void** data, int num);
/*! Like MakeEntries, but here entries are removed.
* \param _data Location to store removed data
*/
status_t RemoveEntries(Transaction& transaction,
Path* path, const btrfs_key& startKey,
void** _data, int num);
@@ -95,6 +109,10 @@ private:
BTree& operator=(const BTree& other);
// no implementation
/*! Search for key in the tree
* \param _value Location to store item if search successful
* \return B_OK when key found, error code otherwise
*/
status_t _Find(Path* path, btrfs_key& key,
void** _value, uint32* _size,
uint32* _offset, btree_traversing type)
@@ -118,7 +136,7 @@ public:
Node(Volume* volume, off_t block);
~Node();
// just return from Header
uint64 LogicalAddress() const
{ return fNode->header.LogicalAddress(); }
uint64 Flags() const
@@ -146,9 +164,10 @@ public:
uint8* ItemData(uint32 i) const
{ return (uint8*)Item(0) + Item(i)->Offset(); }
void Keep();
//! Reset Node and decrements ref-count to the Node's block
void Unset();
//! Load node at block offset from disk
void SetTo(off_t block);
void SetToWritable(off_t block, int32 transactionId, bool empty);
int SpaceUsed() const;
@@ -156,10 +175,21 @@ public:
off_t BlockNum() const { return fBlockNumber;}
bool IsWritable() const { return fWritable; }
/*!
* copy node header, items and items data
* length is size to insert/remove
* if node is a internal node, length isnt used
* length = 0: Copy a whole
* length < 0: removing
* length > 0: inserting
*/
status_t Copy(const Node* origin, uint32 start, uint32 end,
int length) const;
//! Shift data in items between start and end by offset length
status_t MoveEntries(uint32 start, uint32 end, int length) const;
//! Searches for item slot in the node
status_t SearchSlot(const btrfs_key& key, int* slot,
btree_traversing type) const;
private:
@@ -167,9 +197,18 @@ public:
Node& operator=(const Node&);
// no implementation
//! Internal function used by Copy
void _Copy(const Node* origin, uint32 at, uint32 from, uint32 to,
int length) const;
status_t _SpaceCheck(int length) const;
/*!
* calculate used space except the header.
* type is only for leaf node
* type 1: only item space
* type 2: only item data space
* type 3: both type 1 and 2
*/
int _CalculateSpace(uint32 from, uint32 to, uint8 type = 1) const;
btrfs_stream* fNode;
@@ -184,6 +223,7 @@ public:
Path(BTree* tree);
~Path();
Node* GetNode(int level, int* _slot = NULL) const;
Node* SetNode(off_t block, int slot);
Node* SetNode(const Node* node, int slot);
@@ -195,10 +235,36 @@ public:
int Move(int level, int step);
/*!
* Allocate and copy block and do all the changes that it can.
* for now, we only copy-on-write tree block,
* file data is "nocow" by default.
*
* o parent o
* | ===> \
* o x o
*/
status_t CopyOnWrite(Transaction& transaction, int level,
uint32 start, int num, int length);
/*!
* Copy-On-Write all internal nodes start from a specific level.
* level > 0: to root
* level <= 0: to leaf
*
* path cow-path path cow-path
* =================================================
* root cow-root root level < 0
* | | |
* n1 cow-n1 ...______
* | | | \
* n2 cow-n2 n1 cow-n1
* | / | |
* ...____/ n2 cow-n2
* | | |
* leaf level > 0 leaf cow-leaf
*/
status_t InternalCopy(Transaction& transaction, int level);
BTree* Tree() const { return fTree; }
private:
Path(const Path&);
@@ -218,6 +284,7 @@ public:
~TreeIterator();
void Rewind(bool inverse = false);
//! Set current key in the iterator
status_t Find(const btrfs_key& key);
status_t GetNextEntry(void** _value,
uint32* _size = NULL,
@@ -232,9 +299,11 @@ public:
private:
friend class BTree;
//! Iterates through the tree in the specified direction
status_t _Traverse(btree_traversing direction);
status_t _Find(btree_traversing type, btrfs_key& key,
void** _value);
//! Like GetEntry in BTree::Path but checks type and moving
status_t _GetEntry(btree_traversing type, void** _value,
uint32* _size, uint32* _offset);
// called by BTree