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 Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include <stdio.h> 13 #if HAVE_UNISTD_H 14 #include <unistd.h> 15 #endif 16 #include <time.h> 17 #include <string.h> 18 #if HAVE_SYS_STAT_H 19 #include <sys/stat.h> 20 #endif 21 #if HAVE_SYS_TYPES_H 22 #include <sys/types.h> 23 #endif 24 25 #include "ext2_fs.h" 26 #include "ext2fs.h" 27 28 /* 29 * Check for uninit block bitmaps and deal with them appropriately 30 */ 31 static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map, 32 dgrp_t group) 33 { 34 blk_t i; 35 blk_t blk, super_blk, old_desc_blk, new_desc_blk; 36 int old_desc_blocks; 37 38 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 39 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || 40 !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT)) 41 return; 42 43 blk = (group * fs->super->s_blocks_per_group) + 44 fs->super->s_first_data_block; 45 46 ext2fs_super_and_bgd_loc(fs, group, &super_blk, 47 &old_desc_blk, &new_desc_blk, 0); 48 49 if (fs->super->s_feature_incompat & 50 EXT2_FEATURE_INCOMPAT_META_BG) 51 old_desc_blocks = fs->super->s_first_meta_bg; 52 else 53 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks; 54 55 for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) { 56 if ((blk == super_blk) || 57 (old_desc_blk && old_desc_blocks && 58 (blk >= old_desc_blk) && 59 (blk < old_desc_blk + old_desc_blocks)) || 60 (new_desc_blk && (blk == new_desc_blk)) || 61 (blk == fs->group_desc[group].bg_block_bitmap) || 62 (blk == fs->group_desc[group].bg_inode_bitmap) || 63 (blk >= fs->group_desc[group].bg_inode_table && 64 (blk < fs->group_desc[group].bg_inode_table 65 + fs->inode_blocks_per_group))) 66 ext2fs_fast_mark_block_bitmap(map, blk); 67 else 68 ext2fs_fast_unmark_block_bitmap(map, blk); 69 } 70 fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT; 71 ext2fs_group_desc_csum_set(fs, group); 72 } 73 74 /* 75 * Check for uninit inode bitmaps and deal with them appropriately 76 */ 77 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map, 78 dgrp_t group) 79 { 80 ext2_ino_t i, ino; 81 82 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 83 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || 84 !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT)) 85 return; 86 87 ino = (group * fs->super->s_inodes_per_group) + 1; 88 for (i=0; i < fs->super->s_inodes_per_group; i++, ino++) 89 ext2fs_fast_unmark_inode_bitmap(map, ino); 90 91 fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT; 92 check_block_uninit(fs, fs->block_map, group); 93 } 94 95 /* 96 * Right now, just search forward from the parent directory's block 97 * group to find the next free inode. 98 * 99 * Should have a special policy for directories. 100 */ 101 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, 102 int mode EXT2FS_ATTR((unused)), 103 ext2fs_inode_bitmap map, ext2_ino_t *ret) 104 { 105 ext2_ino_t dir_group = 0; 106 ext2_ino_t i; 107 ext2_ino_t start_inode; 108 109 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 110 111 if (!map) 112 map = fs->inode_map; 113 if (!map) 114 return EXT2_ET_NO_INODE_BITMAP; 115 116 if (dir > 0) 117 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super); 118 119 start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1; 120 if (start_inode < EXT2_FIRST_INODE(fs->super)) 121 start_inode = EXT2_FIRST_INODE(fs->super); 122 if (start_inode > fs->super->s_inodes_count) 123 return EXT2_ET_INODE_ALLOC_FAIL; 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 */ 148 errcode_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 */ 187 errcode_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; 227 228 fail: 229 if (buf) 230 ext2fs_free_mem(&buf); 231 return retval; 232 } 233 234 errcode_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 } 262 263 void 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
