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[FREELDR] Add Extents support

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This commit is contained in:
Daniel Victor
2025-02-13 16:34:02 -03:00
committed by Timo Kreuzer
parent a980ad08b4
commit 56c8c8ab4f
1 changed files with 82 additions and 0 deletions
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82
boot/freeldr/freeldr/lib/fs/ext.c
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@@ -40,6 +40,7 @@ BOOLEAN ExtReadInode(PEXT_VOLUME_INFO Volume, ULONG Inode, PEXT_INODE InodeBu
BOOLEAN ExtReadGroupDescriptor(PEXT_VOLUME_INFO Volume, ULONG Group, PEXT_GROUP_DESC GroupBuffer);
ULONG* ExtReadBlockPointerList(PEXT_VOLUME_INFO Volume, PEXT_INODE Inode);
ULONGLONG ExtGetInodeFileSize(PEXT_INODE Inode);
BOOLEAN ExtCopyBlockPointersByExtents(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, PEXT4_EXTENT_HEADER ExtentHeader);
BOOLEAN ExtCopyIndirectBlockPointers(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, ULONG IndirectBlock);
BOOLEAN ExtCopyDoubleIndirectBlockPointers(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, ULONG DoubleIndirectBlock);
BOOLEAN ExtCopyTripleIndirectBlockPointers(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, ULONG TripleIndirectBlock);
@@ -1037,6 +1038,21 @@ ULONG* ExtReadBlockPointerList(PEXT_VOLUME_INFO Volume, PEXT_INODE Inode)
RtlZeroMemory(BlockList, BlockCount * sizeof(ULONG));
// If the file is stored in extents, copy the block pointers by reading the
// extent entries.
if (Inode->Flags & EXT4_INODE_FLAG_EXTENTS)
{
CurrentBlockInList = 0;
if (!ExtCopyBlockPointersByExtents(Volume, BlockList, &CurrentBlockInList, BlockCount, &Inode->ExtentHeader))
{
FrLdrTempFree(BlockList, TAG_EXT_BLOCK_LIST);
return NULL;
}
return BlockList;
}
// Copy the direct block pointers
for (CurrentBlockInList = CurrentBlock = 0;
CurrentBlockInList < BlockCount && CurrentBlock < sizeof(Inode->Blocks.DirectBlocks) / sizeof(*Inode->Blocks.DirectBlocks);
@@ -1090,6 +1106,72 @@ ULONGLONG ExtGetInodeFileSize(PEXT_INODE Inode)
}
}
BOOLEAN ExtCopyBlockPointersByExtents(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, PEXT4_EXTENT_HEADER ExtentHeader)
{
TRACE("ExtCopyBlockPointersByExtents() BlockCount = 0x%p\n", BlockCount);
if (ExtentHeader->Magic != EXT4_EXTENT_HEADER_MAGIC ||
ExtentHeader->Depth > EXT4_EXTENT_MAX_LEVEL)
return FALSE;
ULONG Level = ExtentHeader->Depth;
ULONG Entries = ExtentHeader->Entries;
TRACE("Level: %d\n", Level);
TRACE("Entries: %d\n", Entries);
// If the level is 0, we have a direct extent block mapping
if (!Level)
{
PEXT4_EXTENT Extent = (PVOID)&ExtentHeader[1];
while ((*CurrentBlockInList) < BlockCount && Entries--)
{
BOOLEAN SparseExtent = (Extent->Length > EXT4_EXTENT_MAX_LENGTH);
ULONG Length = SparseExtent ? (Extent->Length - EXT4_EXTENT_MAX_LENGTH) : Extent->Length;
ULONG CurrentBlock = SparseExtent ? 0 : Extent->Start;
// Copy the pointers to the block list
while ((*CurrentBlockInList) < BlockCount && Length--)
{
BlockList[(*CurrentBlockInList)++] = CurrentBlock;
if (!SparseExtent)
CurrentBlock++;
}
Extent++;
}
}
else
{
PEXT4_EXTENT_IDX Extent = (PVOID)&ExtentHeader[1];
PEXT4_EXTENT_HEADER BlockBuffer = FrLdrTempAlloc(Volume->BlockSizeInBytes, TAG_EXT_BUFFER);
if (!BlockBuffer)
{
return FALSE;
}
// Recursively copy the pointers to the block list
while ((*CurrentBlockInList) < BlockCount && Entries--)
{
if (!(ExtReadBlock(Volume, Extent->Leaf, BlockBuffer) &&
ExtCopyBlockPointersByExtents(Volume, BlockList, CurrentBlockInList, BlockCount, BlockBuffer)))
{
FrLdrTempFree(BlockBuffer, TAG_EXT_BUFFER);
return FALSE;
}
Extent++;
}
FrLdrTempFree(BlockBuffer, TAG_EXT_BUFFER);
}
return TRUE;
}
BOOLEAN ExtCopyIndirectBlockPointers(PEXT_VOLUME_INFO Volume, ULONG* BlockList, ULONG* CurrentBlockInList, ULONG BlockCount, ULONG IndirectBlock)
{
ULONG* BlockBuffer;