/* * initialize.c --- initialize a filesystem handle given superblock * parameters. Used by mke2fs when initializing a filesystem. * * Copyright (C) 1994, 1995, 1996 Theodore Ts'o. * * This file may be redistributed under the terms of the GNU Public * License. */ #include #include #include #include #include #include #include #include #if HAVE_ERRNO_H #include #endif #include #include "ext2fs.h" #if defined(__linux__) && defined(EXT2_OS_LINUX) #define CREATOR_OS EXT2_OS_LINUX #elif defined(__gnu__) && defined(EXT2_OS_HURD) #define CREATOR_OS EXT2_OS_HURD #elif defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) #define CREATOR_OS EXT2_OS_FREEBSD #elif defined(LITES) && defined(EXT2_OS_LITES) #define CREATOR_OS EXT2_OS_LITES #else #define CREATOR_OS EXT2_OS_LINUX /* by default */ #endif /* * Note we override the kernel include file's idea of what the default * check interval (never) should be. It's a good idea to check at * least *occasionally*, specially since servers will never rarely get * to reboot, since Linux is so robust these days. :-) * * 180 days (six months) seems like a good value. */ #ifdef EXT2_DFL_CHECKINTERVAL #undef EXT2_DFL_CHECKINTERVAL #endif #define EXT2_DFL_CHECKINTERVAL (86400 * 180) errcode_t ext2fs_initialize(const char *name, int flags, struct ext2_super_block *param, io_manager manager, ext2_filsys *ret_fs) { ext2_filsys fs; errcode_t retval; struct ext2_super_block *super; int frags_per_block; int rem; int overhead = 0; blk_t group_block; int i, j; int numblocks; char *buf; if (!param || !param->s_blocks_count) return EINVAL; fs = (ext2_filsys) malloc(sizeof(struct struct_ext2_filsys)); if (!fs) return ENOMEM; memset(fs, 0, sizeof(struct struct_ext2_filsys)); fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; fs->flags = flags | EXT2_FLAG_RW | ext2fs_native_flag(); retval = manager->open(name, IO_FLAG_RW, &fs->io); if (retval) goto cleanup; fs->device_name = malloc(strlen(name)+1); if (!fs->device_name) { retval = ENOMEM; goto cleanup; } strcpy(fs->device_name, name); fs->super = super = malloc(SUPERBLOCK_SIZE); if (!super) { retval = ENOMEM; goto cleanup; } memset(super, 0, SUPERBLOCK_SIZE); #define set_field(field, default) (super->field = param->field ? \ param->field : (default)) super->s_magic = EXT2_SUPER_MAGIC; super->s_state = EXT2_VALID_FS; set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); set_field(s_errors, EXT2_ERRORS_DEFAULT); #ifdef EXT2_DYNAMIC_REV set_field(s_rev_level, EXT2_GOOD_OLD_REV); if (super->s_rev_level >= EXT2_DYNAMIC_REV) { set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); } #endif set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); super->s_lastcheck = time(NULL); super->s_creator_os = CREATOR_OS; fs->blocksize = EXT2_BLOCK_SIZE(super); fs->fragsize = EXT2_FRAG_SIZE(super); frags_per_block = fs->blocksize / fs->fragsize; set_field(s_blocks_per_group, 8192); /* default: 8192 blocks/group */ super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; super->s_blocks_count = param->s_blocks_count; super->s_r_blocks_count = param->s_r_blocks_count; if (super->s_r_blocks_count >= param->s_blocks_count) { retval = EINVAL; goto cleanup; } retry: fs->group_desc_count = (super->s_blocks_count - super->s_first_data_block + EXT2_BLOCKS_PER_GROUP(super) - 1) / EXT2_BLOCKS_PER_GROUP(super); if (fs->group_desc_count == 0) return EXT2_ET_TOOSMALL; fs->desc_blocks = (fs->group_desc_count + EXT2_DESC_PER_BLOCK(super) - 1) / EXT2_DESC_PER_BLOCK(super); set_field(s_inodes_count, (super->s_blocks_count*fs->blocksize)/4096); /* * There should be at least as many inodes as the user * requested. Figure out how many inodes per group that * should be. But make sure that we don't allocate more than * one bitmap's worth of inodes */ super->s_inodes_per_group = (super->s_inodes_count + fs->group_desc_count - 1) / fs->group_desc_count; if (super->s_inodes_per_group > fs->blocksize*8) super->s_inodes_per_group = fs->blocksize*8; /* * Make sure the number of inodes per group completely fills * the inode table blocks in the descriptor. If not, add some * additional inodes/group. Waste not, want not... */ fs->inode_blocks_per_group = (((super->s_inodes_per_group * EXT2_INODE_SIZE(super)) + EXT2_BLOCK_SIZE(super) - 1) / EXT2_BLOCK_SIZE(super)); super->s_inodes_per_group = ((fs->inode_blocks_per_group * EXT2_BLOCK_SIZE(super)) / EXT2_INODE_SIZE(super)); /* * Finally, make sure the number of inodes per group is a * multiple of 8. This is needed to simplify the bitmap * splicing code. */ super->s_inodes_per_group &= ~7; fs->inode_blocks_per_group = (((super->s_inodes_per_group * EXT2_INODE_SIZE(super)) + EXT2_BLOCK_SIZE(super) - 1) / EXT2_BLOCK_SIZE(super)); /* * adjust inode count to reflect the adjusted inodes_per_group */ super->s_inodes_count = super->s_inodes_per_group * fs->group_desc_count; super->s_free_inodes_count = super->s_inodes_count; /* * Overhead is the number of bookkeeping blocks per group. It * includes the superblock backup, the group descriptor * backups, the inode bitmap, the block bitmap, and the inode * table. */ overhead = 3 + fs->desc_blocks + fs->inode_blocks_per_group; super->s_free_blocks_count = super->s_blocks_count - super->s_first_data_block - (overhead*fs->group_desc_count); /* * See if the last group is big enough to support the * necessary data structures. If not, we need to get rid of * it. */ rem = (super->s_blocks_count - super->s_first_data_block) % super->s_blocks_per_group; if ((fs->group_desc_count == 1) && rem && (rem < overhead)) return EXT2_ET_TOOSMALL; if (rem && (rem < overhead+50)) { super->s_blocks_count -= rem; goto retry; } /* * At this point we know how big the filesystem will be. So * we can do any and all allocations that depend on the block * count. */ buf = malloc(strlen(fs->device_name) + 80); if (!buf) { retval = ENOMEM; goto cleanup; } sprintf(buf, "block bitmap for %s", fs->device_name); retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); if (retval) goto cleanup; sprintf(buf, "inode bitmap for %s", fs->device_name); retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); if (retval) goto cleanup; free(buf); fs->group_desc = malloc(fs->desc_blocks * fs->blocksize); if (!fs->group_desc) { retval = ENOMEM; goto cleanup; } memset(fs->group_desc, 0, fs->desc_blocks * fs->blocksize); /* * Reserve the superblock and group descriptors for each * group, and fill in the correct group statistics for group. * Note that although the block bitmap, inode bitmap, and * inode table have not been allocated (and in fact won't be * by this routine), they are accounted for nevertheless. */ group_block = super->s_first_data_block; for (i = 0; i < fs->group_desc_count; i++) { for (j=0; j < fs->desc_blocks+1; j++) ext2fs_mark_block_bitmap(fs->block_map, group_block + j); if (i == fs->group_desc_count-1) { numblocks = (fs->super->s_blocks_count - fs->super->s_first_data_block) % fs->super->s_blocks_per_group; if (!numblocks) numblocks = fs->super->s_blocks_per_group; } else numblocks = fs->super->s_blocks_per_group; numblocks -= 3 + fs->desc_blocks + fs->inode_blocks_per_group; fs->group_desc[i].bg_free_blocks_count = numblocks; fs->group_desc[i].bg_free_inodes_count = fs->super->s_inodes_per_group; fs->group_desc[i].bg_used_dirs_count = 0; group_block += super->s_blocks_per_group; } ext2fs_mark_super_dirty(fs); ext2fs_mark_bb_dirty(fs); ext2fs_mark_ib_dirty(fs); io_channel_set_blksize(fs->io, fs->blocksize); *ret_fs = fs; return 0; cleanup: ext2fs_free(fs); return retval; }