174 lines
3.6 KiB
C
174 lines
3.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* alloc.c --- allocate new inodes, blocks for ext2fs
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*
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* Copyright (C) 1993, 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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*/
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#include <stdio.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 <time.h>
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#include <string.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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/*
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* Right now, just search forward from the parent directory's block
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* group to find the next free inode.
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*
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* Should have a special policy for directories.
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*/
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errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
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int mode EXT2FS_ATTR((unused)),
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ext2fs_inode_bitmap map, ext2_ino_t *ret)
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{
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ext2_ino_t dir_group = 0;
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ext2_ino_t i;
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ext2_ino_t start_inode;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!map)
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map = fs->inode_map;
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if (!map)
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return EXT2_ET_NO_INODE_BITMAP;
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if (dir > 0)
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dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
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start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
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if (start_inode < EXT2_FIRST_INODE(fs->super))
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start_inode = EXT2_FIRST_INODE(fs->super);
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i = start_inode;
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do {
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if (!ext2fs_fast_test_inode_bitmap(map, i))
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break;
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i++;
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if (i > fs->super->s_inodes_count)
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i = EXT2_FIRST_INODE(fs->super);
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} while (i != start_inode);
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if (ext2fs_test_inode_bitmap(map, i))
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return EXT2_ET_INODE_ALLOC_FAIL;
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*ret = i;
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return 0;
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}
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/*
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* Stupid algorithm --- we now just search forward starting from the
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* goal. Should put in a smarter one someday....
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*/
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errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
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ext2fs_block_bitmap map, blk_t *ret)
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{
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blk_t i;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!map)
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map = fs->block_map;
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if (!map)
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return EXT2_ET_NO_BLOCK_BITMAP;
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if (!goal || (goal >= fs->super->s_blocks_count))
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goal = fs->super->s_first_data_block;
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i = goal;
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do {
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if (!ext2fs_fast_test_block_bitmap(map, i)) {
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*ret = i;
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return 0;
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}
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i++;
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if (i >= fs->super->s_blocks_count)
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i = fs->super->s_first_data_block;
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} while (i != goal);
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return EXT2_ET_BLOCK_ALLOC_FAIL;
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}
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/*
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* This function zeros out the allocated block, and updates all of the
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* appropriate filesystem records.
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*/
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errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
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char *block_buf, blk_t *ret)
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{
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errcode_t retval;
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blk_t block;
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char *buf = NULL;
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if (!block_buf) {
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retval = ext2fs_get_mem(fs->blocksize, &buf);
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if (retval)
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return retval;
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block_buf = buf;
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}
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memset(block_buf, 0, fs->blocksize);
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if (!fs->block_map) {
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retval = ext2fs_read_block_bitmap(fs);
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if (retval)
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goto fail;
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}
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retval = ext2fs_new_block(fs, goal, 0, &block);
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if (retval)
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goto fail;
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retval = io_channel_write_blk(fs->io, block, 1, block_buf);
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if (retval)
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goto fail;
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ext2fs_block_alloc_stats(fs, block, +1);
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*ret = block;
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return 0;
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fail:
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if (buf)
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ext2fs_free_mem(&buf);
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return retval;
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}
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errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
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int num, ext2fs_block_bitmap map, blk_t *ret)
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{
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blk_t b = start;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!map)
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map = fs->block_map;
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if (!map)
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return EXT2_ET_NO_BLOCK_BITMAP;
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if (!b)
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b = fs->super->s_first_data_block;
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if (!finish)
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finish = start;
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if (!num)
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num = 1;
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do {
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if (b+num-1 > fs->super->s_blocks_count)
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b = fs->super->s_first_data_block;
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if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
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*ret = b;
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return 0;
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}
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b++;
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} while (b != finish);
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return EXT2_ET_BLOCK_ALLOC_FAIL;
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}
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