openfs.c revision 96c6a3acd377698cb99ffd9925bec9b20ca4f6f9
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/* 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * openfs.c --- open an ext2 filesystem 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * %Begin-Header% 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This file may be redistributed under the terms of the GNU Public 89ab5563a3196760eb381d102cbb2bc0f7abc6a50Ben Murdoch * License. 9868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) * %End-Header% 10868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) */ 113551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <stdio.h> 133551c9c881056c480085172ff9840cab31610854Torne (Richard Coles)#include <string.h> 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if HAVE_UNISTD_H 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <unistd.h> 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <fcntl.h> 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <time.h> 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if HAVE_SYS_STAT_H 202a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include <sys/stat.h> 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if HAVE_SYS_TYPES_H 232a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include <sys/types.h> 242a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#endif 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "ext2_fs.h" 272a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 282a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 292a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include "ext2fs.h" 302a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include "e2image.h" 312a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 322a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 332a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles){ 342a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) int bg; 352a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) int has_super = 0; 362a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) int ret_blk; 372a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 382a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || 392a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) (i < fs->super->s_first_meta_bg)) 402a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) return (group_block + i + 1); 412a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 422a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i; 432a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (ext2fs_bg_has_super(fs, bg)) 442a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) has_super = 1; 452a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) ret_blk = (fs->super->s_first_data_block + has_super + 462a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) (bg * fs->super->s_blocks_per_group)); 472a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) /* 482a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * If group_block is not the normal value, we're trying to use 492a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * the backup group descriptors and superblock --- so use the 502a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * alternate location of the second block group in the 512a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * metablock group. Ideally we should be testing each bg 522a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * descriptor block individually for correctness, but we don't 532a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * have the infrastructure in place to do that. 542a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) */ 552a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (group_block != fs->super->s_first_data_block && 562a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) ((ret_blk + fs->super->s_blocks_per_group) < 572a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) fs->super->s_blocks_count)) 582a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) ret_blk += fs->super->s_blocks_per_group; 592a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) return ret_blk; 602a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)} 612a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 622a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)errcode_t ext2fs_open(const char *name, int flags, int superblock, 632a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) unsigned int block_size, io_manager manager, 642a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) ext2_filsys *ret_fs) 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles){ 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ext2fs_open2(name, 0, flags, superblock, block_size, 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) manager, ret_fs); 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 692a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 702a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)/* 712a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * Note: if superblock is non-zero, block-size must also be non-zero. 722a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * Superblock and block_size can be zero to use the default size. 732a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Valid flags for ext2fs_open() 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * EXT2_FLAG_RW - Open the filesystem for read/write. 772a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * EXT2_FLAG_FORCE - Open the filesystem even if some of the 782a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * features aren't supported. 794e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 814e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles)errcode_t ext2fs_open2(const char *name, const char *io_options, 824e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) int flags, int superblock, 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned int block_size, io_manager manager, 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ext2_filsys *ret_fs) 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles){ 862a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) ext2_filsys fs; 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) errcode_t retval; 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned long i; 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) __u32 features; 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int j, groups_per_block, blocks_per_group, io_flags; 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) blk_t group_block, blk; 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) char *dest, *cp; 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) struct ext2_group_desc *gdp; 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 972a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 98868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) if (retval) 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return retval; 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) memset(fs, 0, sizeof(struct struct_ext2_filsys)); 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->flags = flags; 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->umask = 022; 1052a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 1062a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (retval) 1072a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) goto cleanup; 1082a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) strcpy(fs->device_name, name); 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) cp = strchr(fs->device_name, '?'); 1105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!io_options && cp) { 1114e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) *cp++ = 0; 1124e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) io_options = cp; 1134e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) } 1144e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) 1154e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) io_flags = 0; 1164e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) if (flags & EXT2_FLAG_RW) 1174e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) io_flags |= IO_FLAG_RW; 1184e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) if (flags & EXT2_FLAG_EXCLUSIVE) 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) io_flags |= IO_FLAG_EXCLUSIVE; 1203551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) retval = manager->open(fs->device_name, io_flags, &fs->io); 1212a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (retval) 1223551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) goto cleanup; 1233551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) if (io_options && 1243551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) (retval = io_channel_set_options(fs->io, io_options))) 1253551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) goto cleanup; 1263551c9c881056c480085172ff9840cab31610854Torne (Richard Coles) fs->image_io = fs->io; 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->io->app_data = fs; 1282a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super); 1292a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (retval) 1305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (flags & EXT2_FLAG_IMAGE_FILE) { 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) &fs->image_header); 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (retval) 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) retval = io_channel_read_blk(fs->io, 0, 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) -(int)sizeof(struct ext2_image_hdr), 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->image_header); 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (retval) 1405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return EXT2_ET_MAGIC_E2IMAGE; 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) superblock = 1; 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) block_size = fs->image_header->fs_blocksize; 1455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /* 1485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * If the user specifies a specific block # for the 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * superblock, then he/she must also specify the block size! 1502a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * Otherwise, read the master superblock located at offset 1512a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) * SUPERBLOCK_OFFSET from the start of the partition. 1525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 15358537e28ecd584eab876aee8be7156509866d23aTorne (Richard Coles) * Note: we only save a backup copy of the superblock if we 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * are reading the superblock from the primary superblock location. 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 1564e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) if (superblock) { 1574e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) if (!block_size) { 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) retval = EXT2_ET_INVALID_ARGUMENT; 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) io_channel_set_blksize(fs->io, block_size); 1625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) group_block = superblock; 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->orig_super = 0; 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 166868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) superblock = 1; 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) group_block = 0; 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (retval) 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 173868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) fs->super); 1745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (retval) 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) goto cleanup; 1765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (fs->orig_super) 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifdef EXT2FS_ENABLE_SWAPFS 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) || 181868fa2fe829687343ffae624259930155e16dbd8Torne (Richard Coles) (fs->flags & EXT2_FLAG_SWAP_BYTES)) { 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) fs->flags |= EXT2_FLAG_SWAP_BYTES; 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ext2fs_swap_super(fs->super); 185 } 186#endif 187 188 if (fs->super->s_magic != EXT2_SUPER_MAGIC) { 189 retval = EXT2_ET_BAD_MAGIC; 190 goto cleanup; 191 } 192 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 193 retval = EXT2_ET_REV_TOO_HIGH; 194 goto cleanup; 195 } 196 197 /* 198 * Check for feature set incompatibility 199 */ 200 if (!(flags & EXT2_FLAG_FORCE)) { 201 features = fs->super->s_feature_incompat; 202#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 203 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 204 features &= !EXT2_LIB_SOFTSUPP_INCOMPAT; 205#endif 206 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 207 retval = EXT2_ET_UNSUPP_FEATURE; 208 goto cleanup; 209 } 210 211 features = fs->super->s_feature_ro_compat; 212#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 213 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 214 features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT; 215#endif 216 if ((flags & EXT2_FLAG_RW) && 217 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 218 retval = EXT2_ET_RO_UNSUPP_FEATURE; 219 goto cleanup; 220 } 221 222 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 223 (fs->super->s_feature_incompat & 224 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { 225 retval = EXT2_ET_UNSUPP_FEATURE; 226 goto cleanup; 227 } 228 } 229 230 fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 231 if (fs->blocksize == 0) { 232 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 233 goto cleanup; 234 } 235 fs->fragsize = EXT2_FRAG_SIZE(fs->super); 236 fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group * 237 EXT2_INODE_SIZE(fs->super) + 238 EXT2_BLOCK_SIZE(fs->super) - 1) / 239 EXT2_BLOCK_SIZE(fs->super)); 240 if (block_size) { 241 if (block_size != fs->blocksize) { 242 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 243 goto cleanup; 244 } 245 } 246 /* 247 * Set the blocksize to the filesystem's blocksize. 248 */ 249 io_channel_set_blksize(fs->io, fs->blocksize); 250 251 /* 252 * If this is an external journal device, don't try to read 253 * the group descriptors, because they're not there. 254 */ 255 if (fs->super->s_feature_incompat & 256 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 257 fs->group_desc_count = 0; 258 *ret_fs = fs; 259 return 0; 260 } 261 262 /* 263 * Read group descriptors 264 */ 265 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 266 if (blocks_per_group == 0 || 267 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 268 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super)) { 269 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 270 goto cleanup; 271 } 272 fs->group_desc_count = ext2fs_div_ceil(fs->super->s_blocks_count - 273 fs->super->s_first_data_block, 274 blocks_per_group); 275 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 276 EXT2_DESC_PER_BLOCK(fs->super)); 277 retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize, 278 &fs->group_desc); 279 if (retval) 280 goto cleanup; 281 if (!group_block) 282 group_block = fs->super->s_first_data_block; 283 dest = (char *) fs->group_desc; 284 groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc); 285 for (i=0 ; i < fs->desc_blocks; i++) { 286 blk = ext2fs_descriptor_block_loc(fs, group_block, i); 287 retval = io_channel_read_blk(fs->io, blk, 1, dest); 288 if (retval) 289 goto cleanup; 290#ifdef EXT2FS_ENABLE_SWAPFS 291 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 292 gdp = (struct ext2_group_desc *) dest; 293 for (j=0; j < groups_per_block; j++) 294 ext2fs_swap_group_desc(gdp++); 295 } 296#endif 297 dest += fs->blocksize; 298 } 299 300 fs->stride = fs->super->s_raid_stride; 301 302 *ret_fs = fs; 303 return 0; 304cleanup: 305 ext2fs_free(fs); 306 return retval; 307} 308 309/* 310 * Set/get the filesystem data I/O channel. 311 * 312 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 313 */ 314errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 315{ 316 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 317 return EXT2_ET_NOT_IMAGE_FILE; 318 if (old_io) { 319 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 320 } 321 return 0; 322} 323 324errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 325{ 326 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 327 return EXT2_ET_NOT_IMAGE_FILE; 328 fs->io = new_io ? new_io : fs->image_io; 329 return 0; 330} 331 332errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 333{ 334 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 335 return EXT2_ET_NOT_IMAGE_FILE; 336 fs->io = fs->image_io = new_io; 337 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 338 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 339 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 340 return 0; 341} 342