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389 lines
12 KiB
C
389 lines
12 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* initialize.c --- initialize a filesystem handle given superblock
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* parameters. Used by mke2fs when initializing a filesystem.
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*
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* Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <fcntl.h>
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#include <time.h>
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#if HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#if HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fs.h"
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#if defined(__linux__) && defined(EXT2_OS_LINUX)
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#define CREATOR_OS EXT2_OS_LINUX
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#else
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#if defined(__GNU__) && defined(EXT2_OS_HURD)
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#define CREATOR_OS EXT2_OS_HURD
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#else
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#if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD)
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#define CREATOR_OS EXT2_OS_FREEBSD
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#else
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#if defined(LITES) && defined(EXT2_OS_LITES)
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#define CREATOR_OS EXT2_OS_LITES
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#else
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#define CREATOR_OS EXT2_OS_LINUX /* by default */
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#endif /* defined(LITES) && defined(EXT2_OS_LITES) */
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#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
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#endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */
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#endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */
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/*
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* Note we override the kernel include file's idea of what the default
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* check interval (never) should be. It's a good idea to check at
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* least *occasionally*, specially since servers will never rarely get
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* to reboot, since Linux is so robust these days. :-)
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*
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* 180 days (six months) seems like a good value.
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*/
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#ifdef EXT2_DFL_CHECKINTERVAL
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#undef EXT2_DFL_CHECKINTERVAL
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#endif
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#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
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/*
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* Calculate the number of GDT blocks to reserve for online filesystem growth.
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* The absolute maximum number of GDT blocks we can reserve is determined by
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* the number of block pointers that can fit into a single block.
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*/
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static int calc_reserved_gdt_blocks(ext2_filsys fs)
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{
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struct ext2_super_block *sb = fs->super;
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unsigned long bpg = sb->s_blocks_per_group;
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unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
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unsigned long max_blocks = 0xffffffff;
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unsigned long rsv_groups;
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int rsv_gdb;
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/* We set it at 1024x the current filesystem size, or
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* the upper block count limit (2^32), whichever is lower.
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*/
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if (sb->s_blocks_count < max_blocks / 1024)
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max_blocks = sb->s_blocks_count * 1024;
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rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
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rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
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if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
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rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
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#ifdef RES_GDT_DEBUG
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printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
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max_blocks, rsv_groups, rsv_gdb);
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#endif
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return rsv_gdb;
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}
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errcode_t ext2fs_initialize(const char *name, int flags,
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struct ext2_super_block *param,
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io_manager manager, ext2_filsys *ret_fs)
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{
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ext2_filsys fs;
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errcode_t retval;
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struct ext2_super_block *super;
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int frags_per_block;
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unsigned int rem;
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unsigned int overhead = 0;
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blk_t group_block;
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unsigned int ipg;
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dgrp_t i;
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blk_t numblocks;
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int rsv_gdt;
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char *buf;
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if (!param || !param->s_blocks_count)
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return EXT2_ET_INVALID_ARGUMENT;
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retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
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if (retval)
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return retval;
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memset(fs, 0, sizeof(struct struct_ext2_filsys));
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fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
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fs->flags = flags | EXT2_FLAG_RW;
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fs->umask = 022;
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#ifdef WORDS_BIGENDIAN
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fs->flags |= EXT2_FLAG_SWAP_BYTES;
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#endif
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retval = manager->open(name, IO_FLAG_RW, &fs->io);
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if (retval)
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goto cleanup;
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fs->image_io = fs->io;
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fs->io->app_data = fs;
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retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
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if (retval)
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goto cleanup;
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strcpy(fs->device_name, name);
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retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
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if (retval)
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goto cleanup;
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fs->super = super;
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memset(super, 0, SUPERBLOCK_SIZE);
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#define set_field(field, default) (super->field = param->field ? \
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param->field : (default))
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super->s_magic = EXT2_SUPER_MAGIC;
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super->s_state = EXT2_VALID_FS;
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set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
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set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
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set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
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set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
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set_field(s_errors, EXT2_ERRORS_DEFAULT);
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set_field(s_feature_compat, 0);
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set_field(s_feature_incompat, 0);
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set_field(s_feature_ro_compat, 0);
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set_field(s_first_meta_bg, 0);
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if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
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retval = EXT2_ET_UNSUPP_FEATURE;
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goto cleanup;
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}
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if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
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retval = EXT2_ET_RO_UNSUPP_FEATURE;
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goto cleanup;
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}
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set_field(s_rev_level, EXT2_GOOD_OLD_REV);
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if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
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set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
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set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
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}
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set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
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super->s_mkfs_time = super->s_lastcheck = time(NULL);
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super->s_creator_os = CREATOR_OS;
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fs->blocksize = EXT2_BLOCK_SIZE(super);
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fs->fragsize = EXT2_FRAG_SIZE(super);
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frags_per_block = fs->blocksize / fs->fragsize;
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/* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
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set_field(s_blocks_per_group, fs->blocksize * 8);
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if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
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super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
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super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
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super->s_blocks_count = param->s_blocks_count;
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super->s_r_blocks_count = param->s_r_blocks_count;
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if (super->s_r_blocks_count >= param->s_blocks_count) {
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retval = EXT2_ET_INVALID_ARGUMENT;
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goto cleanup;
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}
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/*
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* If we're creating an external journal device, we don't need
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* to bother with the rest.
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*/
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if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
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fs->group_desc_count = 0;
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ext2fs_mark_super_dirty(fs);
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*ret_fs = fs;
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return 0;
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}
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retry:
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fs->group_desc_count = (super->s_blocks_count -
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super->s_first_data_block +
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EXT2_BLOCKS_PER_GROUP(super) - 1)
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/ EXT2_BLOCKS_PER_GROUP(super);
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if (fs->group_desc_count == 0) {
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retval = EXT2_ET_TOOSMALL;
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goto cleanup;
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}
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fs->desc_blocks = (fs->group_desc_count +
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EXT2_DESC_PER_BLOCK(super) - 1)
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/ EXT2_DESC_PER_BLOCK(super);
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i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
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set_field(s_inodes_count, super->s_blocks_count / i);
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/*
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* Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
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* that we have enough inodes for the filesystem(!)
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*/
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if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
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super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
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/*
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* There should be at least as many inodes as the user
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* requested. Figure out how many inodes per group that
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* should be. But make sure that we don't allocate more than
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* one bitmap's worth of inodes each group.
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*/
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ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
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fs->group_desc_count;
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if (ipg > fs->blocksize * 8) {
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if (super->s_blocks_per_group >= 256) {
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/* Try again with slightly different parameters */
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super->s_blocks_per_group -= 8;
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super->s_blocks_count = param->s_blocks_count;
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super->s_frags_per_group = super->s_blocks_per_group *
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frags_per_block;
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goto retry;
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} else
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return EXT2_ET_TOO_MANY_INODES;
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}
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if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
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ipg = EXT2_MAX_INODES_PER_GROUP(super);
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super->s_inodes_per_group = ipg;
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if (super->s_inodes_count > ipg * fs->group_desc_count)
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super->s_inodes_count = ipg * fs->group_desc_count;
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/*
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* Make sure the number of inodes per group completely fills
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* the inode table blocks in the descriptor. If not, add some
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* additional inodes/group. Waste not, want not...
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*/
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fs->inode_blocks_per_group = (((super->s_inodes_per_group *
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EXT2_INODE_SIZE(super)) +
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EXT2_BLOCK_SIZE(super) - 1) /
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EXT2_BLOCK_SIZE(super));
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super->s_inodes_per_group = ((fs->inode_blocks_per_group *
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EXT2_BLOCK_SIZE(super)) /
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EXT2_INODE_SIZE(super));
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/*
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* Finally, make sure the number of inodes per group is a
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* multiple of 8. This is needed to simplify the bitmap
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* splicing code.
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*/
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super->s_inodes_per_group &= ~7;
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fs->inode_blocks_per_group = (((super->s_inodes_per_group *
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EXT2_INODE_SIZE(super)) +
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EXT2_BLOCK_SIZE(super) - 1) /
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EXT2_BLOCK_SIZE(super));
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/*
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* adjust inode count to reflect the adjusted inodes_per_group
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*/
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super->s_inodes_count = super->s_inodes_per_group *
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fs->group_desc_count;
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super->s_free_inodes_count = super->s_inodes_count;
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/*
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* check the number of reserved group descriptor table blocks
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*/
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if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
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rsv_gdt = calc_reserved_gdt_blocks(fs);
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else
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rsv_gdt = 0;
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set_field(s_reserved_gdt_blocks, rsv_gdt);
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if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
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retval = EXT2_ET_RES_GDT_BLOCKS;
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goto cleanup;
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}
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/*
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* Overhead is the number of bookkeeping blocks per group. It
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* includes the superblock backup, the group descriptor
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* backups, the inode bitmap, the block bitmap, and the inode
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* table.
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*/
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overhead = (int) (2 + fs->inode_blocks_per_group);
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if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
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overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
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/* This can only happen if the user requested too many inodes */
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if (overhead > super->s_blocks_per_group)
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return EXT2_ET_TOO_MANY_INODES;
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/*
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* See if the last group is big enough to support the
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* necessary data structures. If not, we need to get rid of
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* it.
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*/
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rem = ((super->s_blocks_count - super->s_first_data_block) %
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super->s_blocks_per_group);
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if ((fs->group_desc_count == 1) && rem && (rem < overhead))
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return EXT2_ET_TOOSMALL;
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if (rem && (rem < overhead+50)) {
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super->s_blocks_count -= rem;
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goto retry;
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}
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/*
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* At this point we know how big the filesystem will be. So
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* we can do any and all allocations that depend on the block
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* count.
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*/
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retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
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if (retval)
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goto cleanup;
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sprintf(buf, "block bitmap for %s", fs->device_name);
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retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
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if (retval)
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goto cleanup;
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sprintf(buf, "inode bitmap for %s", fs->device_name);
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retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
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if (retval)
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goto cleanup;
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ext2fs_free_mem(&buf);
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retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
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&fs->group_desc);
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if (retval)
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goto cleanup;
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memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
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/*
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* Reserve the superblock and group descriptors for each
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* group, and fill in the correct group statistics for group.
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* Note that although the block bitmap, inode bitmap, and
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* inode table have not been allocated (and in fact won't be
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* by this routine), they are accounted for nevertheless.
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*/
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group_block = super->s_first_data_block;
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super->s_free_blocks_count = 0;
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for (i = 0; i < fs->group_desc_count; i++) {
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numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
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super->s_free_blocks_count += numblocks;
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fs->group_desc[i].bg_free_blocks_count = numblocks;
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fs->group_desc[i].bg_free_inodes_count =
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fs->super->s_inodes_per_group;
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fs->group_desc[i].bg_used_dirs_count = 0;
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group_block += super->s_blocks_per_group;
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}
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ext2fs_mark_super_dirty(fs);
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ext2fs_mark_bb_dirty(fs);
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ext2fs_mark_ib_dirty(fs);
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io_channel_set_blksize(fs->io, fs->blocksize);
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*ret_fs = fs;
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return 0;
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cleanup:
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ext2fs_free(fs);
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return retval;
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}
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