3 * - By John Hodge (thePowersGang)
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9 #define VERSION VER2(0,90)
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10 #include "ext2_common.h"
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11 #include <modules.h>
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13 #define MIN_BLOCKS_PER_GROUP 2
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14 #define MAX_BLOCK_LOG_SIZE 10 // 1024 << 10 = 1MiB
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17 extern tVFS_NodeType gExt2_DirType;
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19 // === PROTOTYPES ===
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20 int Ext2_Install(char **Arguments);
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21 int Ext2_Cleanup(void);
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22 // - Interface Functions
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23 int Ext2_Detect(int FD);
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24 tVFS_Node *Ext2_InitDevice(const char *Device, const char **Options);
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25 void Ext2_Unmount(tVFS_Node *Node);
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26 void Ext2_CloseFile(tVFS_Node *Node);
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27 // - Internal Helpers
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28 int Ext2_int_GetInode(tVFS_Node *Node, tExt2_Inode *Inode);
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29 Uint64 Ext2_int_GetBlockAddr(tExt2_Disk *Disk, Uint32 *Blocks, int BlockNum);
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30 Uint32 Ext2_int_AllocateInode(tExt2_Disk *Disk, Uint32 Parent);
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31 void Ext2_int_DereferenceInode(tExt2_Disk *Disk, Uint32 Inode);
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32 void Ext2_int_UpdateSuperblock(tExt2_Disk *Disk);
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34 // === SEMI-GLOBALS ===
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35 MODULE_DEFINE(0, VERSION, FS_Ext2, Ext2_Install, Ext2_Cleanup);
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36 tExt2_Disk gExt2_disks[6];
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37 int giExt2_count = 0;
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38 tVFS_Driver gExt2_FSInfo = {
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40 .Detect = Ext2_Detect,
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41 .InitDevice = Ext2_InitDevice,
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42 .Unmount = Ext2_Unmount,
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43 .GetNodeFromINode = NULL
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48 * \fn int Ext2_Install(char **Arguments)
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49 * \brief Install the Ext2 Filesystem Driver
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51 int Ext2_Install(char **Arguments)
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53 VFS_AddDriver( &gExt2_FSInfo );
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54 return MODULE_ERR_OK;
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58 * \brief Clean up driver state before unload
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60 int Ext2_Cleanup(void)
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66 * Detect if a volume is Ext2 formatted
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68 int Ext2_Detect(int FD)
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70 tExt2_SuperBlock sb;
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73 len = VFS_ReadAt(FD, 1024, 1024, &sb);
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76 Log_Debug("Ext2", "_Detect: Read failed? (0x%x != 1024)", len);
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85 Log_Debug("Ext2", "_Detect: s_magic = 0x%x", sb.s_magic);
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91 \brief Initializes a device to be read by by the driver
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92 \param Device String - Device to read from
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93 \param Options NULL Terminated array of option strings
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96 tVFS_Node *Ext2_InitDevice(const char *Device, const char **Options)
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98 tExt2_Disk *disk = NULL;
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101 tExt2_SuperBlock sb;
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104 ENTER("sDevice pOptions", Device, Options);
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107 fd = VFS_Open(Device, VFS_OPENFLAG_READ|VFS_OPENFLAG_WRITE); //Open Device
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109 Log_Warning("EXT2", "Unable to open '%s'", Device);
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114 // Read Superblock at offset 1024
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115 VFS_ReadAt(fd, 1024, 1024, &sb); // Read Superblock
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117 // Sanity Check Magic value
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118 if(sb.s_magic != 0xEF53) {
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119 Log_Warning("EXT2", "Volume '%s' is not an EXT2 volume (0x%x != 0xEF53)",
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120 Device, sb.s_magic);
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124 if( sb.s_blocks_per_group < MIN_BLOCKS_PER_GROUP ) {
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125 Log_Warning("Ext2", "Blocks per group is too small (%i < %i)",
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126 sb.s_blocks_per_group, MIN_BLOCKS_PER_GROUP);
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131 groupCount = DivUp(sb.s_blocks_count, sb.s_blocks_per_group);
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132 LOG("groupCount = %i", groupCount);
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134 // Allocate Disk Information
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135 disk = malloc(sizeof(tExt2_Disk) + sizeof(tExt2_Group)*groupCount);
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137 Log_Warning("EXT2", "Unable to allocate disk structure");
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141 memcpy(&disk->SuperBlock, &sb, 1024);
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142 disk->GroupCount = groupCount;
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144 // Get an inode cache handle
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145 disk->CacheID = Inode_GetHandle();
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148 if( sb.s_log_block_size > MAX_BLOCK_LOG_SIZE ) {
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149 Log_Warning("Ext2", "Block size (log2) too large (%i > %i)",
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150 sb.s_log_block_size, MAX_BLOCK_LOG_SIZE);
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153 disk->BlockSize = 1024 << sb.s_log_block_size;
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154 LOG("Disk->BlockSie = 0x%x (1024 << %i)", disk->BlockSize, sb.s_log_block_size);
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156 // Read Group Information
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157 LOG("sb,s_first_data_block = %x", sb.s_first_data_block);
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160 sb.s_first_data_block * disk->BlockSize + 1024,
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161 sizeof(tExt2_Group)*groupCount,
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165 LOG("Block Group 0");
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166 LOG(".bg_block_bitmap = 0x%x", disk->Groups[0].bg_block_bitmap);
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167 LOG(".bg_inode_bitmap = 0x%x", disk->Groups[0].bg_inode_bitmap);
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168 LOG(".bg_inode_table = 0x%x", disk->Groups[0].bg_inode_table);
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169 LOG("Block Group 1");
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170 LOG(".bg_block_bitmap = 0x%x", disk->Groups[1].bg_block_bitmap);
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171 LOG(".bg_inode_bitmap = 0x%x", disk->Groups[1].bg_inode_bitmap);
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172 LOG(".bg_inode_table = 0x%x", disk->Groups[1].bg_inode_table);
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175 Ext2_int_ReadInode(disk, 2, &inode);
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177 // Create Root Node
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178 memset(&disk->RootNode, 0, sizeof(tVFS_Node));
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179 disk->RootNode.Inode = 2; // Root inode ID
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180 disk->RootNode.ImplPtr = disk; // Save disk pointer
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181 disk->RootNode.Size = -1; // Fill in later (on readdir)
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182 disk->RootNode.Flags = VFS_FFLAG_DIRECTORY;
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184 disk->RootNode.Type = &gExt2_DirType;
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186 // Complete root node
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187 disk->RootNode.UID = inode.i_uid;
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188 disk->RootNode.GID = inode.i_gid;
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189 disk->RootNode.NumACLs = 1;
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190 disk->RootNode.ACLs = &gVFS_ACL_EveryoneRW;
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193 LOG("inode.i_size = 0x%x", inode.i_size);
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194 LOG("inode.i_block[0] = 0x%x", inode.i_block[0]);
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197 LEAVE('p', &disk->RootNode);
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198 return &disk->RootNode;
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208 * \fn void Ext2_Unmount(tVFS_Node *Node)
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209 * \brief Close a mounted device
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211 void Ext2_Unmount(tVFS_Node *Node)
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213 tExt2_Disk *disk = Node->ImplPtr;
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215 VFS_Close( disk->FD );
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216 Inode_ClearCache( disk->CacheID );
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217 memset(disk, 0, sizeof(tExt2_Disk)+disk->GroupCount*sizeof(tExt2_Group));
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222 * \fn void Ext2_CloseFile(tVFS_Node *Node)
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223 * \brief Close a file (Remove it from the cache)
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225 void Ext2_CloseFile(tVFS_Node *Node)
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227 tExt2_Disk *disk = Node->ImplPtr;
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228 ENTER("pNode", Node);
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230 if( Mutex_Acquire(&Node->Lock) != 0 )
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236 if( Node->Flags & VFS_FFLAG_DIRTY )
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239 Log_Warning("Ext2", "TODO: Commit node changes");
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242 int was_not_referenced = (Node->ImplInt == 0);
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243 tVFS_ACL *acls = Node->ACLs;
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244 if( Inode_UncacheNode(disk->CacheID, Node->Inode) == 1 )
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246 if( was_not_referenced )
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248 LOG("Removng inode");
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250 Log_Warning("Ext2", "TODO: Remove inode when not referenced");
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252 if( acls != &gVFS_ACL_EveryoneRW ) {
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255 LOG("Node cleaned");
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258 LOG("Still referenced, releasing lock");
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259 Mutex_Release(&Node->Lock);
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265 //==================================
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266 //= INTERNAL FUNCTIONS =
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267 //==================================
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269 * \fn int Ext2_int_ReadInode(tExt2_Disk *Disk, Uint InodeId, tExt2_Inode *Inode)
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270 * \brief Read an inode into memory
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272 int Ext2_int_ReadInode(tExt2_Disk *Disk, Uint32 InodeId, tExt2_Inode *Inode)
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276 ENTER("pDisk iInodeId pInode", Disk, InodeId, Inode);
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278 if(InodeId == 0) return 0;
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280 InodeId --; // Inodes are numbered starting at 1
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282 group = InodeId / Disk->SuperBlock.s_inodes_per_group;
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283 subId = InodeId % Disk->SuperBlock.s_inodes_per_group;
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285 LOG("group=%i, subId = %i", group, subId);
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288 VFS_ReadAt(Disk->FD,
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289 Disk->Groups[group].bg_inode_table * Disk->BlockSize + sizeof(tExt2_Inode)*subId,
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290 sizeof(tExt2_Inode),
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298 * \brief Write a modified inode out to disk
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300 int Ext2_int_WriteInode(tExt2_Disk *Disk, Uint32 InodeId, tExt2_Inode *Inode)
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303 ENTER("pDisk iInodeId pInode", Disk, InodeId, Inode);
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310 InodeId --; // Inodes are numbered starting at 1
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312 group = InodeId / Disk->SuperBlock.s_inodes_per_group;
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313 subId = InodeId % Disk->SuperBlock.s_inodes_per_group;
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315 LOG("group=%i, subId = %i", group, subId);
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318 VFS_WriteAt(Disk->FD,
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319 Disk->Groups[group].bg_inode_table * Disk->BlockSize + sizeof(tExt2_Inode)*subId,
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320 sizeof(tExt2_Inode),
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329 * \fn Uint64 Ext2_int_GetBlockAddr(tExt2_Disk *Disk, Uint32 *Blocks, int BlockNum)
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330 * \brief Get the address of a block from an inode's list
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331 * \param Disk Disk information structure
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332 * \param Blocks Pointer to an inode's block list
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333 * \param BlockNum Block index in list
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335 Uint64 Ext2_int_GetBlockAddr(tExt2_Disk *Disk, Uint32 *Blocks, int BlockNum)
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338 int dwPerBlock = Disk->BlockSize / 4;
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342 return (Uint64)Blocks[BlockNum] * Disk->BlockSize;
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344 // Single Indirect Blocks
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345 iBlocks = malloc( Disk->BlockSize );
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346 VFS_ReadAt(Disk->FD, (Uint64)Blocks[12]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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349 if(BlockNum < dwPerBlock)
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351 BlockNum = iBlocks[BlockNum];
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353 return (Uint64)BlockNum * Disk->BlockSize;
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356 BlockNum -= dwPerBlock;
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357 // Double Indirect Blocks
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358 if(BlockNum < dwPerBlock*dwPerBlock)
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360 VFS_ReadAt(Disk->FD, (Uint64)Blocks[13]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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361 VFS_ReadAt(Disk->FD, (Uint64)iBlocks[BlockNum/dwPerBlock]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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362 BlockNum = iBlocks[BlockNum%dwPerBlock];
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364 return (Uint64)BlockNum * Disk->BlockSize;
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367 BlockNum -= dwPerBlock*dwPerBlock;
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368 // Triple Indirect Blocks
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369 VFS_ReadAt(Disk->FD, (Uint64)Blocks[14]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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370 VFS_ReadAt(Disk->FD, (Uint64)iBlocks[BlockNum/(dwPerBlock*dwPerBlock)]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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371 VFS_ReadAt(Disk->FD, (Uint64)iBlocks[(BlockNum/dwPerBlock)%dwPerBlock]*Disk->BlockSize, Disk->BlockSize, iBlocks);
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372 BlockNum = iBlocks[BlockNum%dwPerBlock];
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374 return (Uint64)BlockNum * Disk->BlockSize;
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378 * \fn Uint32 Ext2_int_AllocateInode(tExt2_Disk *Disk, Uint32 Parent)
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379 * \brief Allocate an inode (from the current group preferably)
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380 * \param Disk EXT2 Disk Information Structure
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381 * \param Parent Inode ID of the parent (used to locate the child nearby)
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383 Uint32 Ext2_int_AllocateInode(tExt2_Disk *Disk, Uint32 Parent)
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385 Uint start_group = (Parent - 1) / Disk->SuperBlock.s_inodes_per_group;
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386 Uint group = start_group;
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388 if( Disk->SuperBlock.s_free_inodes_count == 0 )
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390 Log_Notice("Ext2", "Ext2_int_AllocateInode - Out of inodes on %p", Disk);
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394 while( group < Disk->GroupCount && Disk->Groups[group].bg_free_inodes_count == 0 )
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396 if( group == Disk->GroupCount )
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399 while( group < start_group && Disk->Groups[group].bg_free_inodes_count == 0 )
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403 if( Disk->Groups[group].bg_free_inodes_count == 0 )
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405 Log_Notice("Ext2", "Ext2_int_AllocateInode - Out of inodes on %p, but superblock says some free", Disk);
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409 // Load bitmap for group
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410 // (s_inodes_per_group / 8) bytes worth
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411 // - Allocate a buffer the size of a sector/block
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412 // - Read in part of the bitmap
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413 // - Search for a free inode
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414 tExt2_Group *bg = &Disk->Groups[group];
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417 const int sector_size = 512;
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418 Uint8 buf[sector_size];
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419 VFS_ReadAt(Disk->FD, Disk->BlockSize*bg->bg_inode_bitmap+ofs, sector_size, buf);
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422 for( byte = 0; byte < sector_size && buf[byte] != 0xFF; byte ++ )
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424 if( byte < sector_size )
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426 for( bit = 0; bit < 8 && buf[byte] & (1 << bit); bit ++)
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429 buf[byte] |= 1 << bit;
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430 VFS_WriteAt(Disk->FD, Disk->BlockSize*bg->bg_inode_bitmap+ofs, sector_size, buf);
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432 bg->bg_free_inodes_count --;
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433 Disk->SuperBlock.s_free_inodes_count --;
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435 Uint32 ret = group * Disk->SuperBlock.s_inodes_per_group + byte * 8 + bit + 1;
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436 Log_Debug("Ext2", "Ext2_int_AllocateInode - Allocated 0x%x", ret);
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440 ofs += sector_size;
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441 } while(ofs < Disk->SuperBlock.s_inodes_per_group / 8);
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443 Log_Notice("Ext2", "Ext2_int_AllocateInode - Out of inodes in group %p:%i but header reported free",
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450 * \brief Reduce the reference count on an inode
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452 void Ext2_int_DereferenceInode(tExt2_Disk *Disk, Uint32 Inode)
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454 Log_Warning("Ext2", "TODO: Impliment Ext2_int_DereferenceInode");
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458 * \fn void Ext2_int_UpdateSuperblock(tExt2_Disk *Disk)
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459 * \brief Updates the superblock
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461 void Ext2_int_UpdateSuperblock(tExt2_Disk *Disk)
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463 int bpg = Disk->SuperBlock.s_blocks_per_group;
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464 int ngrp = Disk->SuperBlock.s_blocks_count / bpg;
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468 VFS_WriteAt(Disk->FD, 1024, 1024, &Disk->SuperBlock);
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471 // at Block Group 1, 3^n, 5^n, 7^n
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474 if(ngrp <= 1) return;
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475 VFS_WriteAt(Disk->FD, 1*bpg*Disk->BlockSize, 1024, &Disk->SuperBlock);
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477 #define INT_MAX (((long long int)1<<(sizeof(int)*8))-1)
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480 for( i = 3; i < ngrp && i < INT_MAX/3; i *= 3 )
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481 VFS_WriteAt(Disk->FD, i*bpg*Disk->BlockSize, 1024, &Disk->SuperBlock);
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484 for( i = 5; i < ngrp && i < INT_MAX/5; i *= 5 )
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485 VFS_WriteAt(Disk->FD, i*bpg*Disk->BlockSize, 1024, &Disk->SuperBlock);
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488 for( i = 7; i < ngrp && i < INT_MAX/7; i *= 7 )
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489 VFS_WriteAt(Disk->FD, i*bpg*Disk->BlockSize, 1024, &Disk->SuperBlock);
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