alloc.c revision a93d40696073076b26bc11052f7cc99588d74dae
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 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 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_bitmap(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_bitmap(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_bitmap(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_block(ext2_filsys fs, blk_t goal, 150 ext2fs_block_bitmap map, blk_t *ret) 151{ 152 blk_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_bitmap(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} 183 184/* 185 * This function zeros out the allocated block, and updates all of the 186 * appropriate filesystem records. 187 */ 188errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal, 189 char *block_buf, blk_t *ret) 190{ 191 errcode_t retval; 192 blk_t block; 193 char *buf = 0; 194 195 if (!block_buf) { 196 retval = ext2fs_get_mem(fs->blocksize, &buf); 197 if (retval) 198 return retval; 199 block_buf = buf; 200 } 201 memset(block_buf, 0, fs->blocksize); 202 203 if (fs->get_alloc_block) { 204 blk64_t new; 205 206 retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new); 207 if (retval) 208 goto fail; 209 block = (blk_t) new; 210 } else { 211 if (!fs->block_map) { 212 retval = ext2fs_read_block_bitmap(fs); 213 if (retval) 214 goto fail; 215 } 216 217 retval = ext2fs_new_block(fs, goal, 0, &block); 218 if (retval) 219 goto fail; 220 } 221 222 retval = io_channel_write_blk(fs->io, block, 1, block_buf); 223 if (retval) 224 goto fail; 225 226 ext2fs_block_alloc_stats(fs, block, +1); 227 *ret = block; 228 229fail: 230 if (buf) 231 ext2fs_free_mem(&buf); 232 return retval; 233} 234 235errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish, 236 int num, ext2fs_block_bitmap map, blk_t *ret) 237{ 238 blk_t b = start; 239 240 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 241 242 if (!map) 243 map = fs->block_map; 244 if (!map) 245 return EXT2_ET_NO_BLOCK_BITMAP; 246 if (!b) 247 b = fs->super->s_first_data_block; 248 if (!finish) 249 finish = start; 250 if (!num) 251 num = 1; 252 do { 253 if (b+num-1 > fs->super->s_blocks_count) 254 b = fs->super->s_first_data_block; 255 if (ext2fs_fast_test_block_bitmap_range(map, b, num)) { 256 *ret = b; 257 return 0; 258 } 259 b++; 260 } while (b != finish); 261 return EXT2_ET_BLOCK_ALLOC_FAIL; 262} 263 264void ext2fs_set_alloc_block_callback(ext2_filsys fs, 265 errcode_t (*func)(ext2_filsys fs, 266 blk64_t goal, 267 blk64_t *ret), 268 errcode_t (**old)(ext2_filsys fs, 269 blk64_t goal, 270 blk64_t *ret)) 271{ 272 if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) 273 return; 274 275 if (old) 276 *old = fs->get_alloc_block; 277 278 fs->get_alloc_block = func; 279} 280