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e2fsprogs
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e2fsprogs/lib/ext2fs/initialize.c

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/*
* 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>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/types.h>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <linux/ext2_fs.h>
#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;
struct ext2fs_sb *s;
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);
s = (struct ext2fs_sb *) super;
#define set_field(field, default) (super->field = param->field ? \
param->field : (default))
#define set_ext2_field(field, default) (s->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_ext2_field(s_feature_compat, 0);
set_ext2_field(s_feature_incompat, 0);
set_ext2_field(s_feature_ro_compat, 0);
if (s->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
return EXT2_ET_UNSUPP_FEATURE;
if (s->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
return EXT2_ET_RO_UNSUPP_FEATURE;
#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;
/* default: (fs->blocksize*8) blocks/group */
set_field(s_blocks_per_group, fs->blocksize*8);
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;
/*
* 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;
super->s_free_blocks_count = 0;
for (i = 0; i < fs->group_desc_count; i++) {
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;
if (ext2fs_bg_has_super(fs, i)) {
for (j=0; j < fs->desc_blocks+1; j++)
ext2fs_mark_block_bitmap(fs->block_map,
group_block + j);
numblocks -= 1 + fs->desc_blocks;
}
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;
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;
}
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