diff options
Diffstat (limited to 'e2fsprogs/ext2fs/initialize.c')
| -rw-r--r-- | e2fsprogs/ext2fs/initialize.c | 387 |
1 files changed, 387 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/initialize.c b/e2fsprogs/ext2fs/initialize.c new file mode 100644 index 0000000..82cd9f1 --- /dev/null +++ b/e2fsprogs/ext2fs/initialize.c @@ -0,0 +1,387 @@ +/* + * 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 Public + * License. + * %End-Header% + */ + +#include <stdio.h> +#include <string.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#include <fcntl.h> +#include <time.h> +#if HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#if HAVE_SYS_TYPES_H +#include <sys/types.h> +#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) */ + +/* + * 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 (86400L * 180L) + +/* + * 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 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 = fs->blocksize / sizeof(struct ext2_group_desc); + unsigned long max_blocks = 0xffffffff; + unsigned long rsv_groups; + 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 = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg; + rsv_gdb = (rsv_groups + gdpb - 1) / 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 = %lu\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; + blk_t group_block; + unsigned int ipg; + dgrp_t i; + blk_t numblocks; + int rsv_gdt; + char *buf; + + 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 + retval = manager->open(name, IO_FLAG_RW, &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, EXT2_DFL_MAX_MNT_COUNT); + 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_first_meta_bg, 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); + } + + set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); + super->s_mkfs_time = 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; + + /* 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 = (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) { + retval = EXT2_ET_TOOSMALL; + goto cleanup; + } + fs->desc_blocks = (fs->group_desc_count + + EXT2_DESC_PER_BLOCK(super) - 1) + / 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 = (super->s_inodes_count + fs->group_desc_count - 1) / + 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 + return EXT2_ET_TOO_MANY_INODES; + } + + if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) + ipg = EXT2_MAX_INODES_PER_GROUP(super); + + super->s_inodes_per_group = ipg; + if (super->s_inodes_count > ipg * fs->group_desc_count) + super->s_inodes_count = ipg * fs->group_desc_count; + + /* + * 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; + + /* + * 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; + } + + /* + * 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 = (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; + + /* This can only happen if the user requested too many inodes */ + if (overhead > super->s_blocks_per_group) + return EXT2_ET_TOO_MANY_INODES; + + /* + * 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. + */ + + retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); + if (retval) + 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; + + ext2fs_free_mem(&buf); + + retval = ext2fs_get_mem((size_t) 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. + */ + group_block = super->s_first_data_block; + super->s_free_blocks_count = 0; + for (i = 0; i < fs->group_desc_count; i++) { + numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); + + 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; + + 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; +} |