+++ /dev/null
-/*
- * Acess OS
- * Ext2 Driver Version 1
- */
-/**
- * \file write.c
- * \brief Second Extended Filesystem Driver
- * \todo Implement file full write support
- */
-#define DEBUG 1
-#define VERBOSE 0
-#include "ext2_common.h"
-
-// === PROTOYPES ===
-Uint64 Ext2_Write(tVFS_Node *node, Uint64 offset, Uint64 length, void *buffer);
-Uint32 Ext2_int_AllocateBlock(tExt2_Disk *Disk, Uint32 PrevBlock);
-void Ext2_int_DeallocateBlock(tExt2_Disk *Disk, Uint32 Block);
- int Ext2_int_AppendBlock(tExt2_Disk *Disk, tExt2_Inode *Inode, Uint32 Block);
-
-// === CODE ===
-/**
- * \fn Uint64 Ext2_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
- * \brief Write to a file
- */
-Uint64 Ext2_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
-{
- tExt2_Disk *disk = Node->ImplPtr;
- tExt2_Inode inode;
- Uint64 base;
- Uint64 retLen;
- Uint block;
- Uint64 allocSize;
- int bNewBlocks = 0;
-
- Debug_HexDump("Ext2_Write", Buffer, Length);
-
- Ext2_int_ReadInode(disk, Node->Inode, &inode);
-
- // Get the ammount of space already allocated
- // - Round size up to block size
- // - block size is a power of two, so this will work
- allocSize = (inode.i_size + disk->BlockSize-1) & ~(disk->BlockSize-1);
-
- // Are we writing to inside the allocated space?
- if( Offset < allocSize )
- {
- // Will we go out of it?
- if(Offset + Length > allocSize) {
- bNewBlocks = 1;
- retLen = allocSize - Offset;
- } else
- retLen = Length;
-
- // Within the allocated space
- block = Offset / disk->BlockSize;
- Offset %= disk->BlockSize;
- base = Ext2_int_GetBlockAddr(disk, inode.i_block, block);
-
- // Write only block (if only one)
- if(Offset + retLen <= disk->BlockSize) {
- VFS_WriteAt(disk->FD, base+Offset, retLen, Buffer);
- if(!bNewBlocks) return Length;
- goto addBlocks; // Ugh! A goto, but it seems unavoidable
- }
-
- // Write First Block
- VFS_WriteAt(disk->FD, base+Offset, disk->BlockSize-Offset, Buffer);
- Buffer += disk->BlockSize-Offset;
- retLen -= disk->BlockSize-Offset;
- block ++;
-
- // Write middle blocks
- while(retLen > disk->BlockSize)
- {
- base = Ext2_int_GetBlockAddr(disk, inode.i_block, block);
- VFS_WriteAt(disk->FD, base, disk->BlockSize, Buffer);
- Buffer += disk->BlockSize;
- retLen -= disk->BlockSize;
- block ++;
- }
-
- // Write last block
- base = Ext2_int_GetBlockAddr(disk, inode.i_block, block);
- VFS_WriteAt(disk->FD, base, retLen, Buffer);
- if(!bNewBlocks) return Length; // Writing in only allocated space
- }
-
-addBlocks:
- Warning("[EXT2 ] File extending is untested");
-
- // Allocate blocks and copy data to them
- retLen = Length - allocSize;
- while( retLen > disk->BlockSize )
- {
- // Allocate a block
- block = Ext2_int_AllocateBlock(disk, base/disk->BlockSize);
- if(!block) return Length - retLen;
- // Add it to this inode
- if( !Ext2_int_AppendBlock(disk, &inode, block) ) {
- Ext2_int_DeallocateBlock(disk, block);
- goto ret;
- }
- // Copy data to the node
- base = block * disk->BlockSize;
- VFS_WriteAt(disk->FD, base, disk->BlockSize, Buffer);
- // Update pointer and size remaining
- inode.i_size += disk->BlockSize;
- Buffer += disk->BlockSize;
- retLen -= disk->BlockSize;
- }
- // Last block :D
- block = Ext2_int_AllocateBlock(disk, base/disk->BlockSize);
- if(!block) goto ret;
- if( !Ext2_int_AppendBlock(disk, &inode, block) ) {
- Ext2_int_DeallocateBlock(disk, block);
- goto ret;
- }
- base = block * disk->BlockSize;
- VFS_WriteAt(disk->FD, base, retLen, Buffer);
- inode.i_size += retLen;
- retLen = 0;
-
-ret: // Makes sure the changes to the inode are committed
- Ext2_int_WriteInode(disk, Node->Inode, &inode);
- return Length - retLen;
-}
-
-/**
- * \fn Uint32 Ext2_int_AllocateBlock(tExt2_Disk *Disk, Uint32 PrevBlock)
- * \brief Allocate a block from the best possible location
- * \param Disk EXT2 Disk Information Structure
- * \param PrevBlock Previous block ID in the file
- */
-Uint32 Ext2_int_AllocateBlock(tExt2_Disk *Disk, Uint32 PrevBlock)
-{
- int bpg = Disk->SuperBlock.s_blocks_per_group;
- Uint blockgroup = PrevBlock / bpg;
- Uint bitmap[Disk->BlockSize/sizeof(Uint)];
- Uint bitsperblock = 8*Disk->BlockSize;
- int i, j = 0;
- Uint block;
-
- // Are there any free blocks?
- if(Disk->SuperBlock.s_free_blocks_count == 0) return 0;
-
- if(Disk->Groups[blockgroup].bg_free_blocks_count > 0)
- {
- // Search block group's bitmap
- for(i = 0; i < bpg; i++)
- {
- // Get the block in the bitmap block
- j = i & (bitsperblock-1);
-
- // Read in if needed
- if(j == 0) {
- VFS_ReadAt(
- Disk->FD,
- (Uint64)Disk->Groups[blockgroup].bg_block_bitmap + i / bitsperblock,
- Disk->BlockSize,
- bitmap
- );
- }
-
- // Fast Check
- if( bitmap[j/32] == -1 ) {
- j = (j + 31) & ~31;
- continue;
- }
-
- // Is the bit set?
- if( bitmap[j/32] & (1 << (j%32)) )
- continue;
-
- // Ooh! We found one
- break;
- }
- if( i < bpg ) {
- Warning("[EXT2 ] Inconsistency detected, Group Free Block count is non-zero when no free blocks exist");
- goto checkAll; // Search the entire filesystem for a free block
- // Goto needed for neatness
- }
-
- // Mark as used
- bitmap[j/32] |= (1 << (j%32));
- VFS_WriteAt(
- Disk->FD,
- (Uint64)Disk->Groups[blockgroup].bg_block_bitmap + i / bitsperblock,
- Disk->BlockSize,
- bitmap
- );
- block = i;
- Disk->Groups[blockgroup].bg_free_blocks_count --;
- #if EXT2_UPDATE_WRITEBACK
- //Ext2_int_UpdateBlockGroup(Disk, blockgroup);
- #endif
- }
- else
- {
- checkAll:
- Warning("[EXT2 ] TODO - Implement using blocks outside the current block group");
- return 0;
- }
-
- // Reduce global count
- Disk->SuperBlock.s_free_blocks_count --;
- #if EXT2_UPDATE_WRITEBACK
- Ext2_int_UpdateSuperblock(Disk);
- #endif
-
- return block;
-}
-
-/**
- * \brief Deallocates a block
- */
-void Ext2_int_DeallocateBlock(tExt2_Disk *Disk, Uint32 Block)
-{
-}
-
-/**
- * \brief Append a block to an inode
- */
-int Ext2_int_AppendBlock(tExt2_Disk *Disk, tExt2_Inode *Inode, Uint32 Block)
-{
- int nBlocks;
- int dwPerBlock = Disk->BlockSize / 4;
- Uint32 *blocks;
- Uint32 id1, id2;
-
- nBlocks = (Inode->i_size + Disk->BlockSize - 1) / Disk->BlockSize;
-
- // Direct Blocks
- if( nBlocks < 12 ) {
- Inode->i_block[nBlocks] = Block;
- return 0;
- }
-
- blocks = malloc( Disk->BlockSize );
- if(!blocks) return 1;
-
- nBlocks -= 12;
- // Single Indirect
- if( nBlocks < dwPerBlock)
- {
- // Allocate/Get Indirect block
- if( nBlocks == 0 ) {
- Inode->i_block[12] = Ext2_int_AllocateBlock(Disk, Inode->i_block[0]);
- if( !Inode->i_block[12] ) {
- free(blocks);
- return 1;
- }
- memset(blocks, 0, Disk->BlockSize);
- }
- else
- VFS_ReadAt(Disk->FD, Inode->i_block[12]*Disk->BlockSize, Disk->BlockSize, blocks);
-
- blocks[nBlocks] = Block;
-
- VFS_WriteAt(Disk->FD, Inode->i_block[12]*Disk->BlockSize, Disk->BlockSize, blocks);
- free(blocks);
- return 0;
- }
-
- nBlocks += dwPerBlock;
- // Double Indirect
- if( nBlocks < dwPerBlock*dwPerBlock )
- {
- // Allocate/Get Indirect block
- if( nBlocks == 0 ) {
- Inode->i_block[13] = Ext2_int_AllocateBlock(Disk, Inode->i_block[0]);
- if( !Inode->i_block[13] ) {
- free(blocks);
- return 1;
- }
- memset(blocks, 0, Disk->BlockSize);
- }
- else
- VFS_ReadAt(Disk->FD, Inode->i_block[13]*Disk->BlockSize, Disk->BlockSize, blocks);
-
- // Allocate / Get Indirect lvl2 Block
- if( nBlocks % dwPerBlock == 0 ) {
- id1 = Ext2_int_AllocateBlock(Disk, Inode->i_block[0]);
- if( !id1 ) {
- free(blocks);
- return 1;
- }
- blocks[nBlocks/dwPerBlock] = id1;
- // Write back indirect 1 block
- VFS_WriteAt(Disk->FD, Inode->i_block[13]*Disk->BlockSize, Disk->BlockSize, blocks);
- memset(blocks, 0, Disk->BlockSize);
- }
- else {
- id1 = blocks[nBlocks / dwPerBlock];
- VFS_ReadAt(Disk->FD, id1*Disk->BlockSize, Disk->BlockSize, blocks);
- }
-
- blocks[nBlocks % dwPerBlock] = Block;
-
- VFS_WriteAt(Disk->FD, id1*Disk->BlockSize, Disk->BlockSize, blocks);
- free(blocks);
- return 0;
- }
-
- nBlocks -= dwPerBlock*dwPerBlock;
- // Triple Indirect
- if( nBlocks < dwPerBlock*dwPerBlock*dwPerBlock )
- {
- // Allocate/Get Indirect block
- if( nBlocks == 0 ) {
- Inode->i_block[14] = Ext2_int_AllocateBlock(Disk, Inode->i_block[0]);
- if( !Inode->i_block[14] ) {
- free(blocks);
- return 1;
- }
- memset(blocks, 0, Disk->BlockSize);
- }
- else
- VFS_ReadAt(Disk->FD, Inode->i_block[14]*Disk->BlockSize, Disk->BlockSize, blocks);
-
- // Allocate / Get Indirect lvl2 Block
- if( (nBlocks/dwPerBlock) % dwPerBlock == 0 && nBlocks % dwPerBlock == 0 )
- {
- id1 = Ext2_int_AllocateBlock(Disk, Inode->i_block[0]);
- if( !id1 ) {
- free(blocks);
- return 1;
- }
- blocks[nBlocks/dwPerBlock] = id1;
- // Write back indirect 1 block
- VFS_WriteAt(Disk->FD, Inode->i_block[14]*Disk->BlockSize, Disk->BlockSize, blocks);
- memset(blocks, 0, Disk->BlockSize);
- }
- else {
- id1 = blocks[nBlocks / (dwPerBlock*dwPerBlock)];
- VFS_ReadAt(Disk->FD, id1*Disk->BlockSize, Disk->BlockSize, blocks);
- }
-
- // Allocate / Get Indirect Level 3 Block
- if( nBlocks % dwPerBlock == 0 ) {
- id2 = Ext2_int_AllocateBlock(Disk, id1);
- if( !id2 ) {
- free(blocks);
- return 1;
- }
- blocks[(nBlocks/dwPerBlock)%dwPerBlock] = id2;
- // Write back indirect 1 block
- VFS_WriteAt(Disk->FD, id1*Disk->BlockSize, Disk->BlockSize, blocks);
- memset(blocks, 0, Disk->BlockSize);
- }
- else {
- id2 = blocks[(nBlocks/dwPerBlock)%dwPerBlock];
- VFS_ReadAt(Disk->FD, id2*Disk->BlockSize, Disk->BlockSize, blocks);
- }
-
- blocks[nBlocks % dwPerBlock] = Block;
-
- VFS_WriteAt(Disk->FD, id2*Disk->BlockSize, Disk->BlockSize, blocks);
- free(blocks);
- return 0;
- }
-
- Warning("[EXT2 ] Inode %i cannot have a block appended to it, all indirects used");
- free(blocks);
- return 1;
-}
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