alloc.c revision c71d781370c29f283fdaea01783b5257e508df0f
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 * Check for uninit block bitmaps and deal with them appropriately 31 */ 32static check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map, 33 dgrp_t group) 34{ 35 int i; 36 blk_t blk, super_blk, old_desc_blk, new_desc_blk; 37 int old_desc_blocks; 38 39 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 40 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || 41 !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT)) 42 return; 43 44 blk = (group * fs->super->s_blocks_per_group) + 45 fs->super->s_first_data_block; 46 47 ext2fs_super_and_bgd_loc(fs, group, &super_blk, 48 &old_desc_blk, &new_desc_blk, 0); 49 50 if (fs->super->s_feature_incompat & 51 EXT2_FEATURE_INCOMPAT_META_BG) 52 old_desc_blocks = fs->super->s_first_meta_bg; 53 else 54 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks; 55 56 for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) { 57 if ((blk == super_blk) || 58 (old_desc_blk && old_desc_blocks && 59 (blk >= old_desc_blk) && 60 (blk < old_desc_blk + old_desc_blocks)) || 61 (new_desc_blk && (blk == new_desc_blk)) || 62 (blk == fs->group_desc[group].bg_block_bitmap) || 63 (blk == fs->group_desc[group].bg_inode_bitmap) || 64 (blk >= fs->group_desc[group].bg_inode_table && 65 (blk < fs->group_desc[group].bg_inode_table 66 + fs->inode_blocks_per_group))) 67 ext2fs_fast_mark_block_bitmap(map, blk); 68 else 69 ext2fs_fast_unmark_block_bitmap(map, blk); 70 } 71 fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT; 72 ext2fs_group_desc_csum_set(fs, group); 73} 74 75/* 76 * Check for uninit inode bitmaps and deal with them appropriately 77 */ 78static check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map, 79 dgrp_t group) 80{ 81 int i; 82 ext2_ino_t ino; 83 84 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 85 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || 86 !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT)) 87 return; 88 89 ino = (group * fs->super->s_inodes_per_group) + 1; 90 for (i=0; i < fs->super->s_inodes_per_group; i++, ino++) 91 ext2fs_fast_unmark_inode_bitmap(map, ino); 92 93 fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT; 94 check_block_uninit(fs, fs->block_map, group); 95} 96 97/* 98 * Right now, just search forward from the parent directory's block 99 * group to find the next free inode. 100 * 101 * Should have a special policy for directories. 102 */ 103errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, 104 int mode EXT2FS_ATTR((unused)), 105 ext2fs_inode_bitmap map, ext2_ino_t *ret) 106{ 107 ext2_ino_t dir_group = 0; 108 ext2_ino_t i; 109 ext2_ino_t start_inode; 110 111 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 112 113 if (!map) 114 map = fs->inode_map; 115 if (!map) 116 return EXT2_ET_NO_INODE_BITMAP; 117 118 if (dir > 0) 119 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super); 120 121 start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1; 122 if (start_inode < EXT2_FIRST_INODE(fs->super)) 123 start_inode = EXT2_FIRST_INODE(fs->super); 124 i = start_inode; 125 126 do { 127 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0) 128 check_inode_uninit(fs, map, (i - 1) / 129 EXT2_INODES_PER_GROUP(fs->super)); 130 131 if (!ext2fs_fast_test_inode_bitmap(map, i)) 132 break; 133 i++; 134 if (i > fs->super->s_inodes_count) 135 i = EXT2_FIRST_INODE(fs->super); 136 } while (i != start_inode); 137 138 if (ext2fs_test_inode_bitmap(map, i)) 139 return EXT2_ET_INODE_ALLOC_FAIL; 140 *ret = i; 141 return 0; 142} 143 144/* 145 * Stupid algorithm --- we now just search forward starting from the 146 * goal. Should put in a smarter one someday.... 147 */ 148errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal, 149 ext2fs_block_bitmap map, blk_t *ret) 150{ 151 blk_t i; 152 153 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 154 155 if (!map) 156 map = fs->block_map; 157 if (!map) 158 return EXT2_ET_NO_BLOCK_BITMAP; 159 if (!goal || (goal >= fs->super->s_blocks_count)) 160 goal = fs->super->s_first_data_block; 161 i = goal; 162 check_block_uninit(fs, map, 163 (i - fs->super->s_first_data_block) / 164 EXT2_BLOCKS_PER_GROUP(fs->super)); 165 do { 166 if (((i - fs->super->s_first_data_block) % 167 EXT2_BLOCKS_PER_GROUP(fs->super)) == 0) 168 check_block_uninit(fs, map, 169 (i - fs->super->s_first_data_block) / 170 EXT2_BLOCKS_PER_GROUP(fs->super)); 171 172 if (!ext2fs_fast_test_block_bitmap(map, i)) { 173 *ret = i; 174 return 0; 175 } 176 i++; 177 if (i >= fs->super->s_blocks_count) 178 i = fs->super->s_first_data_block; 179 } while (i != goal); 180 return EXT2_ET_BLOCK_ALLOC_FAIL; 181} 182 183/* 184 * This function zeros out the allocated block, and updates all of the 185 * appropriate filesystem records. 186 */ 187errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal, 188 char *block_buf, blk_t *ret) 189{ 190 errcode_t retval; 191 blk_t block; 192 char *buf = 0; 193 194 if (!block_buf) { 195 retval = ext2fs_get_mem(fs->blocksize, &buf); 196 if (retval) 197 return retval; 198 block_buf = buf; 199 } 200 memset(block_buf, 0, fs->blocksize); 201 202 if (fs->get_alloc_block) { 203 blk64_t new; 204 205 retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new); 206 if (retval) 207 goto fail; 208 block = (blk_t) new; 209 } else { 210 if (!fs->block_map) { 211 retval = ext2fs_read_block_bitmap(fs); 212 if (retval) 213 goto fail; 214 } 215 216 retval = ext2fs_new_block(fs, goal, 0, &block); 217 if (retval) 218 goto fail; 219 } 220 221 retval = io_channel_write_blk(fs->io, block, 1, block_buf); 222 if (retval) 223 goto fail; 224 225 ext2fs_block_alloc_stats(fs, block, +1); 226 *ret = block; 227 228fail: 229 if (buf) 230 ext2fs_free_mem(&buf); 231 return retval; 232} 233 234errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish, 235 int num, ext2fs_block_bitmap map, blk_t *ret) 236{ 237 blk_t b = start; 238 239 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 240 241 if (!map) 242 map = fs->block_map; 243 if (!map) 244 return EXT2_ET_NO_BLOCK_BITMAP; 245 if (!b) 246 b = fs->super->s_first_data_block; 247 if (!finish) 248 finish = start; 249 if (!num) 250 num = 1; 251 do { 252 if (b+num-1 > fs->super->s_blocks_count) 253 b = fs->super->s_first_data_block; 254 if (ext2fs_fast_test_block_bitmap_range(map, b, num)) { 255 *ret = b; 256 return 0; 257 } 258 b++; 259 } while (b != finish); 260 return EXT2_ET_BLOCK_ALLOC_FAIL; 261} 262 263void ext2fs_set_alloc_block_callback(ext2_filsys fs, 264 errcode_t (*func)(ext2_filsys fs, 265 blk64_t goal, 266 blk64_t *ret), 267 errcode_t (**old)(ext2_filsys fs, 268 blk64_t goal, 269 blk64_t *ret)) 270{ 271 if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) 272 return; 273 274 if (old) 275 *old = fs->get_alloc_block; 276 277 fs->get_alloc_block = func; 278} 279