alloc.c revision 8f82ef9860339039b54a324be137fbc09b762358
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 void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map, 33 dgrp_t group) 34{ 35 blk_t i; 36 blk64_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_loc2(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_bitmap2(map, blk); 68 else 69 ext2fs_fast_unmark_block_bitmap2(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 void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map, 79 dgrp_t group) 80{ 81 ext2_ino_t i, ino; 82 83 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 84 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || 85 !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT)) 86 return; 87 88 ino = (group * fs->super->s_inodes_per_group) + 1; 89 for (i=0; i < fs->super->s_inodes_per_group; i++, ino++) 90 ext2fs_fast_unmark_inode_bitmap2(map, ino); 91 92 fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT; 93 check_block_uninit(fs, fs->block_map, group); 94} 95 96/* 97 * Right now, just search forward from the parent directory's block 98 * group to find the next free inode. 99 * 100 * Should have a special policy for directories. 101 */ 102errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, 103 int mode EXT2FS_ATTR((unused)), 104 ext2fs_inode_bitmap map, ext2_ino_t *ret) 105{ 106 ext2_ino_t dir_group = 0; 107 ext2_ino_t i; 108 ext2_ino_t start_inode; 109 110 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 111 112 if (!map) 113 map = fs->inode_map; 114 if (!map) 115 return EXT2_ET_NO_INODE_BITMAP; 116 117 if (dir > 0) 118 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super); 119 120 start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1; 121 if (start_inode < EXT2_FIRST_INODE(fs->super)) 122 start_inode = EXT2_FIRST_INODE(fs->super); 123 if (start_inode > fs->super->s_inodes_count) 124 return EXT2_ET_INODE_ALLOC_FAIL; 125 i = start_inode; 126 127 do { 128 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0) 129 check_inode_uninit(fs, map, (i - 1) / 130 EXT2_INODES_PER_GROUP(fs->super)); 131 132 if (!ext2fs_fast_test_inode_bitmap2(map, i)) 133 break; 134 i++; 135 if (i > fs->super->s_inodes_count) 136 i = EXT2_FIRST_INODE(fs->super); 137 } while (i != start_inode); 138 139 if (ext2fs_test_inode_bitmap2(map, i)) 140 return EXT2_ET_INODE_ALLOC_FAIL; 141 *ret = i; 142 return 0; 143} 144 145/* 146 * Stupid algorithm --- we now just search forward starting from the 147 * goal. Should put in a smarter one someday.... 148 */ 149errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal, 150 ext2fs_block_bitmap map, blk64_t *ret) 151{ 152 blk64_t i; 153 154 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 155 156 if (!map) 157 map = fs->block_map; 158 if (!map) 159 return EXT2_ET_NO_BLOCK_BITMAP; 160 if (!goal || (goal >= fs->super->s_blocks_count)) 161 goal = fs->super->s_first_data_block; 162 i = goal; 163 check_block_uninit(fs, map, 164 (i - fs->super->s_first_data_block) / 165 EXT2_BLOCKS_PER_GROUP(fs->super)); 166 do { 167 if (((i - fs->super->s_first_data_block) % 168 EXT2_BLOCKS_PER_GROUP(fs->super)) == 0) 169 check_block_uninit(fs, map, 170 (i - fs->super->s_first_data_block) / 171 EXT2_BLOCKS_PER_GROUP(fs->super)); 172 173 if (!ext2fs_fast_test_block_bitmap2(map, i)) { 174 *ret = i; 175 return 0; 176 } 177 i++; 178 if (i >= fs->super->s_blocks_count) 179 i = fs->super->s_first_data_block; 180 } while (i != goal); 181 return EXT2_ET_BLOCK_ALLOC_FAIL; 182} 183 184errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal, 185 ext2fs_block_bitmap map, blk_t *ret) 186{ 187 errcode_t retval; 188 blk64_t val; 189 retval = ext2fs_new_block2(fs, goal, map, &val); 190 if (!retval) 191 *ret = (blk_t) val; 192 return retval; 193} 194 195/* 196 * This function zeros out the allocated block, and updates all of the 197 * appropriate filesystem records. 198 */ 199errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal, 200 char *block_buf, blk64_t *ret) 201{ 202 errcode_t retval; 203 blk64_t block; 204 char *buf = 0; 205 206 if (!block_buf) { 207 retval = ext2fs_get_mem(fs->blocksize, &buf); 208 if (retval) 209 return retval; 210 block_buf = buf; 211 } 212 memset(block_buf, 0, fs->blocksize); 213 214 if (fs->get_alloc_block) { 215 retval = (fs->get_alloc_block)(fs, goal, &block); 216 if (retval) 217 goto fail; 218 } else { 219 if (!fs->block_map) { 220 retval = ext2fs_read_block_bitmap(fs); 221 if (retval) 222 goto fail; 223 } 224 225 retval = ext2fs_new_block2(fs, goal, 0, &block); 226 if (retval) 227 goto fail; 228 } 229 230 retval = io_channel_write_blk64(fs->io, block, 1, block_buf); 231 if (retval) 232 goto fail; 233 234 ext2fs_block_alloc_stats2(fs, block, +1); 235 *ret = block; 236 237fail: 238 if (buf) 239 ext2fs_free_mem(&buf); 240 return retval; 241} 242 243errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal, 244 char *block_buf, blk_t *ret) 245{ 246 errcode_t retval; 247 blk64_t val; 248 retval = ext2fs_alloc_block2(fs, goal, block_buf, &val); 249 if (!retval) 250 *ret = (blk_t) val; 251 return retval; 252} 253 254errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish, 255 int num, ext2fs_block_bitmap map, blk64_t *ret) 256{ 257 blk64_t b = start; 258 259 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 260 261 if (!map) 262 map = fs->block_map; 263 if (!map) 264 return EXT2_ET_NO_BLOCK_BITMAP; 265 if (!b) 266 b = fs->super->s_first_data_block; 267 if (!finish) 268 finish = start; 269 if (!num) 270 num = 1; 271 do { 272 if (b+num-1 > fs->super->s_blocks_count) 273 b = fs->super->s_first_data_block; 274 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) { 275 *ret = b; 276 return 0; 277 } 278 b++; 279 } while (b != finish); 280 return EXT2_ET_BLOCK_ALLOC_FAIL; 281} 282 283errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish, 284 int num, ext2fs_block_bitmap map, blk_t *ret) 285{ 286 errcode_t retval; 287 blk64_t val; 288 retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val); 289 if(!retval) 290 *ret = (blk_t) val; 291 return retval; 292} 293 294void ext2fs_set_alloc_block_callback(ext2_filsys fs, 295 errcode_t (*func)(ext2_filsys fs, 296 blk64_t goal, 297 blk64_t *ret), 298 errcode_t (**old)(ext2_filsys fs, 299 blk64_t goal, 300 blk64_t *ret)) 301{ 302 if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) 303 return; 304 305 if (old) 306 *old = fs->get_alloc_block; 307 308 fs->get_alloc_block = func; 309} 310