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ExtentAllocator.cpp
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ExtentAllocator.cpp
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/*
* Copyright 2017, Chế Vũ Gia Hy, cvghy116@gmail.com.
* This file may be used under the terms of the MIT License.
*/
#include "ExtentAllocator.h"
#include "Chunk.h"
CachedExtent*
CachedExtent::Create(uint64 offset, uint64 length, uint64 flags)
{
CachedExtent* self = new(std::nothrow) CachedExtent();
if (self == NULL)
return NULL;
self->offset = offset;
self->length = length;
self->refCount = 0;
if ((flags & BTRFS_EXTENT_FLAG_ALLOCATED) != 0)
self->refCount = 1;
self->flags = flags;
self->item = NULL;
return self;
}
void
CachedExtent::Delete()
{
if (item != NULL)
free(item);
item = NULL;
delete this;
}
bool
CachedExtent::IsAllocated() const
{
return (flags & BTRFS_EXTENT_FLAG_ALLOCATED) != 0;
}
bool
CachedExtent::IsData() const
{
return (flags & BTRFS_EXTENT_FLAG_DATA) != 0;
}
void
CachedExtent::Info() const
{
const char* extentType = "allocated tree block";
if (IsAllocated() == false && IsData() == false)
extentType = "free tree block";
else if (IsAllocated() == false && IsData() == true)
extentType = "free data extent";
else if (IsAllocated() == true && IsData() == true)
extentType = "allocated data extent";
TRACE("%s at %" B_PRIu64 " length %" B_PRIu64 " refCount %i\n",
extentType, offset, length, refCount);
}
// ExtentTree Implementation
CachedExtentTree::CachedExtentTree(const TreeDefinition& definition)
:
AVLTree<TreeDefinition>(definition)
{
}
CachedExtentTree::~CachedExtentTree()
{
Delete();
}
/* Find extent that cover or after "offset"
* it must also satisfy the condition "type".
*/
status_t
CachedExtentTree::FindNext(CachedExtent** chosen, uint64 offset, uint64 type)
{
CachedExtent* found = Find(offset);
while (found != NULL && found->flags != type)
found = Next(found);
if (found == NULL)
return B_ENTRY_NOT_FOUND;
*chosen = found;
return B_OK;
}
/* this will insert all free extents that are holes,
* created by existed allocated extents in the tree
* from lowerBound to upperBound
*/
status_t
CachedExtentTree::FillFreeExtents(uint64 lowerBound, uint64 upperBound)
{
CachedExtent* node = FindClosest(lowerBound, false);
CachedExtent* hole = NULL;
status_t status = B_OK;
uint64 flags = node->flags & (~BTRFS_EXTENT_FLAG_ALLOCATED);
if (lowerBound < node->offset) {
hole = CachedExtent::Create(lowerBound, node->offset - lowerBound,
flags);
status = _AddFreeExtent(hole);
if (status != B_OK)
return status;
}
CachedExtent* next = NULL;
while ((next = Next(node)) != NULL && next->End() < upperBound) {
if (node->End() == next->offset) {
node = next;
continue;
}
hole = CachedExtent::Create(node->End(), next->offset - node->End(),
flags);
status = _AddFreeExtent(hole);
if (status != B_OK)
return status;
node = next;
}
// final node should be a right most node
if (upperBound > node->End()) {
hole = CachedExtent::Create(node->End(), upperBound - node->End(),
flags);
status = _AddFreeExtent(hole);
}
return status;
}
void
CachedExtentTree::_RemoveExtent(CachedExtent* node)
{
node->refCount--;
if (node->refCount <= 0) {
Remove(node);
node->Delete();
}
}
status_t
CachedExtentTree::_AddAllocatedExtent(CachedExtent* node)
{
if (node == NULL || node->IsAllocated() == false)
return B_BAD_VALUE;
CachedExtent* found = Find(node->offset);
if (found == NULL) {
Insert(node);
return B_OK;
}
if ((found->IsData() && !node->IsData())
|| (!found->IsData() && node->IsData())) {
// this shouldn't happen as because different type has
// its different region for locating.
node->Delete();
return B_BAD_VALUE;
}
if (found->IsAllocated() == false) {
// split free extents (found)
if (node->End() > found->End()) {
// TODO: when to handle this ?
node->Delete();
return B_BAD_VALUE;
}
// |----- found ------|
// |-- node ---|
uint64 diff = node->offset - found->offset;
found->offset += diff + node->length;
found->length -= diff + node->length;
// diff < 0 couldn't happen because of the Compare function
if (diff > 0) {
CachedExtent* leftEmpty = CachedExtent::Create(
node->offset - diff, diff, found->flags);
_AddFreeExtent(leftEmpty);
}
if (found->length == 0) {
// free-extent that has no space
_RemoveExtent(found);
}
Insert(node);
return B_OK;
}
if (found->length == node->length) {
found->refCount++;
} else {
// TODO: What should we do in this case ?
return B_BAD_VALUE;
}
node->Delete();
return B_OK;
}
status_t
CachedExtentTree::_AddFreeExtent(CachedExtent* node)
{
if (node == NULL || node->IsAllocated() == true)
return B_BAD_VALUE;
CachedExtent* found = Find(node->offset);
if (found == NULL) {
Insert(node);
_CombineFreeExtent(node);
return B_OK;
}
if ((found->IsData() && !node->IsData())
|| (!found->IsData() && node->IsData())) {
// this shouldn't happen as because different type has
// its different region for locating.
node->Delete();
return B_BAD_VALUE;
}
if (found->End() < node->End()) {
// |---- found-----|
// |--- node ------|
CachedExtent* rightEmpty = CachedExtent::Create(found->End(),
node->End() - found->End(), node->flags);
_AddFreeExtent(rightEmpty);
node->length -= node->End() - found->End();
}
if (found->IsAllocated() == true) {
// free part of the allocated extents(found)
// |----- found ------|
// |-- node ---|
uint64 diff = node->offset - found->offset;
found->offset += diff + node->length;
found->length -= diff + node->length;
// diff < 0 couldn't happen because of the Compare function
if (diff > 0){
CachedExtent* left = CachedExtent::Create(node->offset - diff,
diff, found->flags);
_AddAllocatedExtent(left);
}
if (found->length == 0)
_RemoveExtent(found);
Insert(node);
_CombineFreeExtent(node);
}
return B_OK;
}
status_t
CachedExtentTree::AddExtent(CachedExtent* extent)
{
if (extent->IsAllocated() == true)
return _AddAllocatedExtent(extent);
return _AddFreeExtent(extent);
}
void
CachedExtentTree::_CombineFreeExtent(CachedExtent* node)
{
// node should be inserted first to call this function,
// otherwise it will overdelete.
if (node->IsAllocated() == true)
return;
CachedExtent* other = Next(node);
if (other != NULL) {
if (node->End() == other->offset && node->flags == other->flags) {
node->length += other->length;
_RemoveExtent(other);
}
}
other = Previous(node);
if (other != NULL) {
if (other->End() == node->offset && node->flags == other->flags) {
other->length += node->length;
_RemoveExtent(node);
}
}
}
void
CachedExtentTree::_DumpInOrder(CachedExtent* node) const
{
if (node == NULL)
return;
_DumpInOrder(_GetValue(node->left));
node->Info();
_DumpInOrder(_GetValue(node->right));
}
void
CachedExtentTree::DumpInOrder() const
{
TRACE("\n");
_DumpInOrder(RootNode());
TRACE("\n");
}
void
CachedExtentTree::Delete()
{
_Delete(RootNode());
Clear();
}
void
CachedExtentTree::_Delete(CachedExtent* node)
{
if (node == NULL)
return;
_Delete(_GetValue(node->left));
_Delete(_GetValue(node->right));
node->Delete();
}
// BlockGroup
BlockGroup::BlockGroup(BTree* extentTree)
:
fItem(NULL)
{
fCurrentExtentTree = new(std::nothrow) BTree(extentTree->SystemVolume(),
extentTree->RootBlock());
}
BlockGroup::~BlockGroup()
{
if (fItem != NULL) {
free(fItem);
fItem = NULL;
}
delete fCurrentExtentTree;
fCurrentExtentTree = NULL;
}
status_t
BlockGroup::SetExtentTree(off_t rootAddress)
{
status_t status = fCurrentExtentTree->SetRoot(rootAddress, NULL);
if (status != B_OK)
return status;
if (fItem != NULL) {
// re-allocate BlockGroup;
uint64 flags = Flags();
return Initialize(flags);
}
return B_OK;
}
/* Initialize BlockGroup that has flag
*/
status_t
BlockGroup::Initialize(uint64 flag)
{
if (fCurrentExtentTree == NULL)
return B_NO_MEMORY;
if (fItem != NULL)
free(fItem);
TRACE("BlockGroup::Initialize() find block group has flag: %"
B_PRIu64 "\n", flag);
BTree::Path path(fCurrentExtentTree);
fKey.SetObjectID(0);
// find first item in extent to get the ObjectID
// ignore type because block_group is not always the first item
fKey.SetType(BTRFS_KEY_TYPE_ANY);
fCurrentExtentTree->FindNext(&path, fKey, NULL);
fKey.SetType(BTRFS_KEY_TYPE_BLOCKGROUP_ITEM);
fKey.SetOffset(0);
status_t status;
while(true) {
status = fCurrentExtentTree->FindNext(&path, fKey, (void**)&fItem);
if ((Flags() & flag) == flag || status != B_OK)
break;
fKey.SetObjectID(End());
fKey.SetOffset(0);
}
if (status != B_OK)
ERROR("BlockGroup::Initialize() cannot find block group\n");
return status;
}
status_t
BlockGroup::LoadExtent(CachedExtentTree* tree, bool inverse)
{
if (fItem == NULL)
return B_NO_INIT;
uint64 flags = (Flags() & BTRFS_BLOCKGROUP_FLAG_DATA) != 0 ?
BTRFS_EXTENT_FLAG_DATA : BTRFS_EXTENT_FLAG_TREE_BLOCK;
if (inverse == false)
flags |= BTRFS_EXTENT_FLAG_ALLOCATED;
uint64 start = Start();
CachedExtent* insert;
void* data;
uint64 extentSize = fCurrentExtentTree->SystemVolume()->BlockSize();
btrfs_key key;
key.SetType(BTRFS_KEY_TYPE_METADATA_ITEM);
if ((flags & BTRFS_EXTENT_FLAG_DATA) != 0)
key.SetType(BTRFS_KEY_TYPE_EXTENT_ITEM);
key.SetObjectID(start);
key.SetOffset(0);
TreeIterator iterator(fCurrentExtentTree, key);
status_t status;
while(true) {
status = iterator.GetNextEntry(&data);
key = iterator.Key();
if (status != B_OK) {
if (key.ObjectID() != Start())
break;
// When we couldn't find the item and key has
// objectid == BlockGroup's objectID, because
// key's type < BLOCKGROUP_ITEM
continue;
}
if (inverse == false) {
if ((flags & BTRFS_EXTENT_FLAG_DATA) != 0)
extentSize = key.Offset();
insert = CachedExtent::Create(key.ObjectID(), extentSize, flags);
insert->item = (btrfs_extent*)data;
} else {
extentSize = key.ObjectID() - start;
insert = CachedExtent::Create(start, extentSize, flags);
free(data); // free extent doesn't have data;
}
_InsertExtent(tree, insert);
start = key.ObjectID() + extentSize;
}
if (inverse == true)
_InsertExtent(tree, start, End() - start, flags);
return B_OK;
}
status_t
BlockGroup::_InsertExtent(CachedExtentTree* tree, uint64 start, uint64 length,
uint64 flags)
{
CachedExtent* extent = CachedExtent::Create(start, length, flags);
return _InsertExtent(tree, extent);
}
status_t
BlockGroup::_InsertExtent(CachedExtentTree* tree, CachedExtent* extent)
{
if (extent->length == 0)
return B_BAD_VALUE;
status_t status = tree->AddExtent(extent);
if (status != B_OK) {
return status;
}
return B_OK;
}
// ExtentAllocator
ExtentAllocator::ExtentAllocator(Volume* volume)
:
fVolume(volume),
fTree(NULL),
fStart((uint64)-1),
fEnd(0)
{
fTree = new(std::nothrow) CachedExtentTree(TreeDefinition());
}
ExtentAllocator::~ExtentAllocator()
{
delete fTree;
fTree = NULL;
}
status_t
ExtentAllocator::_LoadExtentTree(uint64 flags)
{
TRACE("ExtentAllocator::_LoadExtentTree() flags: %" B_PRIu64 "\n", flags);
BlockGroup blockGroup(fVolume->ExtentTree());
status_t status = blockGroup.Initialize(flags);
if (status != B_OK)
return status;
for (int i = 0; i < BTRFS_NUM_ROOT_BACKUPS; i++) {
uint64 extentRootAddr =
fVolume->SuperBlock().backup_roots[i].ExtentRoot();
if (extentRootAddr == 0)
continue; // new device has 0 root address
status = blockGroup.SetExtentTree(extentRootAddr);
if (status != B_OK)
return status;
status = blockGroup.LoadExtent(fTree, false);
if (status != B_OK)
return status;
}
if (fTree->IsEmpty()) // 4 backup roots is 0
return B_OK;
uint64 lowerBound = blockGroup.Start();
uint64 upperBound = blockGroup.End();
status = fTree->FillFreeExtents(lowerBound, upperBound);
if (status != B_OK) {
ERROR("ExtentAllocator::_LoadExtentTree() could not fill free extents"
"start %" B_PRIu64 " end %" B_PRIu64 "\n", lowerBound,
upperBound);
return status;
}
if (fStart > lowerBound)
fStart = lowerBound;
if (fEnd < upperBound)
fEnd = upperBound;
return B_OK;
}
status_t
ExtentAllocator::Initialize()
{
TRACE("ExtentAllocator::Initialize()\n");
if (fTree == NULL)
return B_NO_MEMORY;
status_t status = _LoadExtentTree(BTRFS_BLOCKGROUP_FLAG_DATA);
if (status != B_OK) {
ERROR("ExtentAllocator:: could not load exent tree (data)\n");
return status;
}
status = _LoadExtentTree(BTRFS_BLOCKGROUP_FLAG_SYSTEM);
if (status != B_OK) {
ERROR("ExtentAllocator:: could not load exent tree (system)\n");
return status;
}
status = _LoadExtentTree(BTRFS_BLOCKGROUP_FLAG_METADATA);
if (status != B_OK) {
ERROR("ExtentAllocator:: could not load exent tree (metadata)\n");
return status;
}
fTree->DumpInOrder();
return B_OK;
}
/* Allocate extent that
* startwith or after "start" and has size >= "size"
* For now the allocating strategy is "first fit"
*/
status_t
ExtentAllocator::_Allocate(uint64& found, uint64 start, uint64 size,
uint64 type)
{
TRACE("ExtentAllocator::_Allocate() start %" B_PRIu64 " size %" B_PRIu64 " type %"
B_PRIu64 "\n", start, size, type);
CachedExtent* chosen;
status_t status;
while(true) {
status = fTree->FindNext(&chosen, start, type);
if (status != B_OK)
return status;
if (TreeDefinition().Compare(start, chosen) == 0) {
if (chosen->End() - start >= size) {
// if covered and have enough space for allocating
break;
}
start = chosen->End(); // set new start and retry
} else
start = chosen->offset;
}
TRACE("ExtentAllocator::_Allocate() found %" B_PRIu64 "\n", start);
chosen = CachedExtent::Create(start, size,
type | BTRFS_EXTENT_FLAG_ALLOCATED);
status = fTree->AddExtent(chosen);
if (status != B_OK)
return status;
found = start;
return B_OK;
}
// Allocate block for metadata
// flags is BLOCKGROUP's flags
status_t
ExtentAllocator::AllocateTreeBlock(uint64& found, uint64 start, uint64 flags)
{
// TODO: implement more features here with flags, e.g DUP, RAID, etc
BlockGroup blockGroup(fVolume->ExtentTree());
status_t status = blockGroup.Initialize(flags);
if (status != B_OK)
return status;
if (start == (uint64)-1)
start = blockGroup.Start();
// normalize inputs
uint64 remainder = start % fVolume->BlockSize();
if (remainder != 0)
start += fVolume->BlockSize() - remainder;
status = _Allocate(found, start, fVolume->BlockSize(),
BTRFS_EXTENT_FLAG_TREE_BLOCK);
if (status != B_OK)
return status;
// check here because tree block locate in 2 blockgroups (system and
// metadata), and there might be a case one can get over the limit.
if (found >= blockGroup.End())
return B_BAD_DATA;
return B_OK;
}
// Allocate block for file data
status_t
ExtentAllocator::AllocateDataBlock(uint64& found, uint64 size, uint64 start,
uint64 flags)
{
// TODO: implement more features here with flags, e.g DUP, RAID, etc
if (start == (uint64)-1) {
BlockGroup blockGroup(fVolume->ExtentTree());
status_t status = blockGroup.Initialize(flags);
if (status != B_OK)
return status;
start = blockGroup.Start();
}
// normalize inputs
uint64 remainder = start % fVolume->SectorSize();
if (remainder != 0)
start += fVolume->SectorSize() - remainder;
size = size / fVolume->SectorSize() * fVolume->SectorSize();
return _Allocate(found, start, size, BTRFS_EXTENT_FLAG_DATA);
}