1 /* 2 * alloc.c --- allocate new inodes, blocks for ext2fs 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Public 8 * License. 9 * %End-Header% 10 * 11 */ 12 13 #include <stdio.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 #include <time.h> 18 #include <string.h> 19 #if HAVE_SYS_STAT_H 20 #include <sys/stat.h> 21 #endif 22 #if HAVE_SYS_TYPES_H 23 #include <sys/types.h> 24 #endif 25 26 #include "ext2_fs.h" 27 #include "ext2fs.h" 28 29 /* 30 * Right now, just search forward from the parent directory's block 31 * group to find the next free inode. 32 * 33 * Should have a special policy for directories. 34 */ 35 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, 36 int mode EXT2FS_ATTR((unused)), 37 ext2fs_inode_bitmap map, ext2_ino_t *ret) 38 { 39 ext2_ino_t dir_group = 0; 40 ext2_ino_t i; 41 ext2_ino_t start_inode; 42 43 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 44 45 if (!map) 46 map = fs->inode_map; 47 if (!map) 48 return EXT2_ET_NO_INODE_BITMAP; 49 50 if (dir > 0) 51 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super); 52 53 start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1; 54 if (start_inode < EXT2_FIRST_INODE(fs->super)) 55 start_inode = EXT2_FIRST_INODE(fs->super); 56 i = start_inode; 57 58 do { 59 if (!ext2fs_fast_test_inode_bitmap(map, i)) 60 break; 61 i++; 62 if (i > fs->super->s_inodes_count) 63 i = EXT2_FIRST_INODE(fs->super); 64 } while (i != start_inode); 65 66 if (ext2fs_test_inode_bitmap(map, i)) 67 return EXT2_ET_INODE_ALLOC_FAIL; 68 *ret = i; 69 return 0; 70 } 71 72 /* 73 * Stupid algorithm --- we now just search forward starting from the 74 * goal. Should put in a smarter one someday.... 75 */ 76 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal, 77 ext2fs_block_bitmap map, blk_t *ret) 78 { 79 blk_t i; 80 81 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 82 83 if (!map) 84 map = fs->block_map; 85 if (!map) 86 return EXT2_ET_NO_BLOCK_BITMAP; 87 if (!goal || (goal >= fs->super->s_blocks_count)) 88 goal = fs->super->s_first_data_block; 89 i = goal; 90 do { 91 if (!ext2fs_fast_test_block_bitmap(map, i)) { 92 *ret = i; 93 return 0; 94 } 95 i++; 96 if (i >= fs->super->s_blocks_count) 97 i = fs->super->s_first_data_block; 98 } while (i != goal); 99 return EXT2_ET_BLOCK_ALLOC_FAIL; 100 } 101 102 /* 103 * This function zeros out the allocated block, and updates all of the 104 * appropriate filesystem records. 105 */ 106 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal, 107 char *block_buf, blk_t *ret) 108 { 109 errcode_t retval; 110 blk_t block; 111 char *buf = 0; 112 113 if (!block_buf) { 114 retval = ext2fs_get_mem(fs->blocksize, &buf); 115 if (retval) 116 return retval; 117 block_buf = buf; 118 } 119 memset(block_buf, 0, fs->blocksize); 120 121 if (!fs->block_map) { 122 retval = ext2fs_read_block_bitmap(fs); 123 if (retval) 124 goto fail; 125 } 126 127 retval = ext2fs_new_block(fs, goal, 0, &block); 128 if (retval) 129 goto fail; 130 131 retval = io_channel_write_blk(fs->io, block, 1, block_buf); 132 if (retval) 133 goto fail; 134 135 ext2fs_block_alloc_stats(fs, block, +1); 136 *ret = block; 137 138 fail: 139 if (buf) 140 ext2fs_free_mem(&buf); 141 return retval; 142 } 143 144 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish, 145 int num, ext2fs_block_bitmap map, blk_t *ret) 146 { 147 blk_t b = start; 148 149 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 150 151 if (!map) 152 map = fs->block_map; 153 if (!map) 154 return EXT2_ET_NO_BLOCK_BITMAP; 155 if (!b) 156 b = fs->super->s_first_data_block; 157 if (!finish) 158 finish = start; 159 if (!num) 160 num = 1; 161 do { 162 if (b+num-1 > fs->super->s_blocks_count) 163 b = fs->super->s_first_data_block; 164 if (ext2fs_fast_test_block_bitmap_range(map, b, num)) { 165 *ret = b; 166 return 0; 167 } 168 b++; 169 } while (b != finish); 170 return EXT2_ET_BLOCK_ALLOC_FAIL; 171 } 172 173
