/* * initialize.c --- initialize a filesystem handle given superblock * parameters. Used by mke2fs when initializing a filesystem. * * Copyright (C) 1994, 1995, 1996 Theodore Ts'o. * * %Begin-Header% * This file may be redistributed under the terms of the GNU Library * General Public License, version 2. * %End-Header% */ #include #include #if HAVE_UNISTD_H #include #endif #include #include #if HAVE_SYS_STAT_H #include #endif #if HAVE_SYS_TYPES_H #include #endif #include "ext2_fs.h" #include "ext2fs.h" #if defined(__linux__) && defined(EXT2_OS_LINUX) #define CREATOR_OS EXT2_OS_LINUX #else #if defined(__GNU__) && defined(EXT2_OS_HURD) #define CREATOR_OS EXT2_OS_HURD #else #if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) #define CREATOR_OS EXT2_OS_FREEBSD #else #if defined(LITES) && defined(EXT2_OS_LITES) #define CREATOR_OS EXT2_OS_LITES #else #define CREATOR_OS EXT2_OS_LINUX /* by default */ #endif /* defined(LITES) && defined(EXT2_OS_LITES) */ #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */ #endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */ #endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */ /* * Calculate the number of GDT blocks to reserve for online filesystem growth. * The absolute maximum number of GDT blocks we can reserve is determined by * the number of block pointers that can fit into a single block. */ static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs) { struct ext2_super_block *sb = fs->super; unsigned long bpg = sb->s_blocks_per_group; unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb); unsigned long max_blocks = 0xffffffff; unsigned long rsv_groups; unsigned int rsv_gdb; /* We set it at 1024x the current filesystem size, or * the upper block count limit (2^32), whichever is lower. */ if (sb->s_blocks_count < max_blocks / 1024) max_blocks = sb->s_blocks_count * 1024; rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg); rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks; if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb)) rsv_gdb = EXT2_ADDR_PER_BLOCK(sb); #ifdef RES_GDT_DEBUG printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n", max_blocks, rsv_groups, rsv_gdb); #endif return rsv_gdb; } 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; unsigned int rem; unsigned int overhead = 0; unsigned int ipg; dgrp_t i; blk_t numblocks; int rsv_gdt; int csum_flag; int io_flags; char *buf = 0; char c; if (!param || !param->s_blocks_count) return EXT2_ET_INVALID_ARGUMENT; retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); if (retval) return retval; memset(fs, 0, sizeof(struct struct_ext2_filsys)); fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; fs->flags = flags | EXT2_FLAG_RW; fs->umask = 022; #ifdef WORDS_BIGENDIAN fs->flags |= EXT2_FLAG_SWAP_BYTES; #endif io_flags = IO_FLAG_RW; if (flags & EXT2_FLAG_EXCLUSIVE) io_flags |= IO_FLAG_EXCLUSIVE; retval = manager->open(name, io_flags, &fs->io); if (retval) goto cleanup; fs->image_io = fs->io; fs->io->app_data = fs; retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); if (retval) goto cleanup; strcpy(fs->device_name, name); retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); if (retval) goto cleanup; fs->super = super; 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, 0); set_field(s_errors, EXT2_ERRORS_DEFAULT); set_field(s_feature_compat, 0); set_field(s_feature_incompat, 0); set_field(s_feature_ro_compat, 0); set_field(s_default_mount_opts, 0); set_field(s_first_meta_bg, 0); set_field(s_raid_stride, 0); /* default stride size: 0 */ set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */ set_field(s_log_groups_per_flex, 0); set_field(s_flags, 0); if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { retval = EXT2_ET_UNSUPP_FEATURE; goto cleanup; } if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { retval = EXT2_ET_RO_UNSUPP_FEATURE; goto cleanup; } 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); if (super->s_inode_size >= sizeof(struct ext2_inode_large)) { int extra_isize = sizeof(struct ext2_inode_large) - EXT2_GOOD_OLD_INODE_SIZE; set_field(s_min_extra_isize, extra_isize); set_field(s_want_extra_isize, extra_isize); } } else { super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; } set_field(s_checkinterval, 0); super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : 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; /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ set_field(s_blocks_per_group, fs->blocksize * 8); if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 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 = EXT2_ET_INVALID_ARGUMENT; goto cleanup; } /* * If we're creating an external journal device, we don't need * to bother with the rest. */ if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { fs->group_desc_count = 0; ext2fs_mark_super_dirty(fs); *ret_fs = fs; return 0; } retry: fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count - super->s_first_data_block, EXT2_BLOCKS_PER_GROUP(super)); if (fs->group_desc_count == 0) { retval = EXT2_ET_TOOSMALL; goto cleanup; } fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, EXT2_DESC_PER_BLOCK(super)); i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; set_field(s_inodes_count, super->s_blocks_count / i); /* * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so * that we have enough inodes for the filesystem(!) */ if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) super->s_inodes_count = EXT2_FIRST_INODE(super)+1; /* * 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 each group. */ ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count); if (ipg > fs->blocksize * 8) { if (super->s_blocks_per_group >= 256) { /* Try again with slightly different parameters */ super->s_blocks_per_group -= 8; super->s_blocks_count = param->s_blocks_count; super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; goto retry; } else { retval = EXT2_ET_TOO_MANY_INODES; goto cleanup; } } if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) ipg = EXT2_MAX_INODES_PER_GROUP(super); ipg_retry: super->s_inodes_per_group = ipg; /* * 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 */ if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) { ipg--; goto ipg_retry; } super->s_inodes_count = super->s_inodes_per_group * fs->group_desc_count; super->s_free_inodes_count = super->s_inodes_count; /* * check the number of reserved group descriptor table blocks */ if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) rsv_gdt = calc_reserved_gdt_blocks(fs); else rsv_gdt = 0; set_field(s_reserved_gdt_blocks, rsv_gdt); if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { retval = EXT2_ET_RES_GDT_BLOCKS; goto cleanup; } /* * Calculate the maximum number of bookkeeping blocks per * group. It includes the superblock, the block group * descriptors, the block bitmap, the inode bitmap, the inode * table, and the reserved gdt blocks. */ overhead = (int) (3 + fs->inode_blocks_per_group + fs->desc_blocks + super->s_reserved_gdt_blocks); /* This can only happen if the user requested too many inodes */ if (overhead > super->s_blocks_per_group) { retval = EXT2_ET_TOO_MANY_INODES; goto cleanup; } /* * See if the last group is big enough to support the * necessary data structures. If not, we need to get rid of * it. We need to recalculate the overhead for the last block * group, since it might or might not have a superblock * backup. */ overhead = (int) (2 + fs->inode_blocks_per_group); if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; rem = ((super->s_blocks_count - super->s_first_data_block) % super->s_blocks_per_group); if ((fs->group_desc_count == 1) && rem && (rem < overhead)) { retval = EXT2_ET_TOOSMALL; goto cleanup; } 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. */ retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); if (retval) goto cleanup; strcpy(buf, "block bitmap for "); strcat(buf, fs->device_name); retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); if (retval) goto cleanup; strcpy(buf, "inode bitmap for "); strcat(buf, fs->device_name); retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); if (retval) goto cleanup; ext2fs_free_mem(&buf); retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, &fs->group_desc); if (retval) goto cleanup; memset(fs->group_desc, 0, (size_t) 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. * * If FLEX_BG meta-data grouping is used, only account for the * superblock and group descriptors (the inode tables and * bitmaps will be accounted for when allocated). */ super->s_free_blocks_count = 0; csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super, EXT4_FEATURE_RO_COMPAT_GDT_CSUM); for (i = 0; i < fs->group_desc_count; i++) { /* * Don't set the BLOCK_UNINIT group for the last group * because the block bitmap needs to be padded. */ if (csum_flag) { if (i != fs->group_desc_count - 1) fs->group_desc[i].bg_flags |= EXT2_BG_BLOCK_UNINIT; fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT; numblocks = super->s_inodes_per_group; if (i == 0) numblocks -= super->s_first_ino; fs->group_desc[i].bg_itable_unused = numblocks; } numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); if (fs->super->s_log_groups_per_flex) numblocks += 2 + fs->inode_blocks_per_group; super->s_free_blocks_count += numblocks; 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; ext2fs_group_desc_csum_set(fs, i); } c = (char) 255; if (((int) c) == -1) { super->s_flags |= EXT2_FLAGS_SIGNED_HASH; } else { super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH; } 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: free(buf); ext2fs_free(fs); return retval; }