lib/ext2fs/alloc.c

   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 "config.h"
  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 #define min(a, b) ((a) < (b) ? (a) : (b))
  30
  31 #undef DEBUG
  32
  33 #ifdef DEBUG
  34 # define dbg_printf(f, a...)  do {printf(f, ## a); fflush(stdout); } while (0)
  35 #else
  36 # define dbg_printf(f, a...)
  37 #endif
  38
  39 /*
  40  * Clear the uninit block bitmap flag if necessary
  41  */
  42 void ext2fs_clear_block_uninit(ext2_filsys fs, dgrp_t group)
  43 {
  44         if (group >= fs->group_desc_count ||
  45             !ext2fs_has_group_desc_csum(fs) ||
  46             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
  47                 return;
  48
  49         /* uninit block bitmaps are now initialized in read_bitmaps() */
  50
  51         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  52         ext2fs_group_desc_csum_set(fs, group);
  53         ext2fs_mark_super_dirty(fs);
  54         ext2fs_mark_bb_dirty(fs);
  55 }
  56
  57 /*
  58  * Check for uninit inode bitmaps and deal with them appropriately
  59  */
  60 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  61                           dgrp_t group)
  62 {
  63         ext2_ino_t      i, ino;
  64
  65         if (group >= fs->group_desc_count ||
  66             !ext2fs_has_group_desc_csum(fs) ||
  67             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  68                 return;
  69
  70         ino = (group * fs->super->s_inodes_per_group) + 1;
  71         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  72                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  73
  74         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  75         /* Mimics what the kernel does */
  76         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  77         ext2fs_group_desc_csum_set(fs, group);
  78         ext2fs_mark_ib_dirty(fs);
  79         ext2fs_mark_super_dirty(fs);
  80 }
  81
  82 /*
  83  * Right now, just search forward from the parent directory's block
  84  * group to find the next free inode.
  85  *
  86  * Should have a special policy for directories.
  87  */
  88 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
  89                            int mode EXT2FS_ATTR((unused)),
  90                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
  91 {
  92         ext2_ino_t      start_inode = 0;
  93         ext2_ino_t      i, ino_in_group, upto, first_zero;
  94         errcode_t       retval;
  95         dgrp_t          group;
  96
  97         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  98
  99         if (!map)
 100                 map = fs->inode_map;
 101         if (!map)
 102                 return EXT2_ET_NO_INODE_BITMAP;
 103
 104         if (dir > 0) {
 105                 group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 106                 start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 107         }
 108         if (start_inode < EXT2_FIRST_INODE(fs->super))
 109                 start_inode = EXT2_FIRST_INODE(fs->super);
 110         if (start_inode > fs->super->s_inodes_count)
 111                 return EXT2_ET_INODE_ALLOC_FAIL;
 112         i = start_inode;
 113         do {
 114                 ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
 115                 group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
 116
 117                 check_inode_uninit(fs, map, group);
 118                 upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
 119                 if (i < start_inode && upto >= start_inode)
 120                         upto = start_inode - 1;
 121                 if (upto > fs->super->s_inodes_count)
 122                         upto = fs->super->s_inodes_count;
 123
 124                 retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
 125                                                               &first_zero);
 126                 if (retval == 0) {
 127                         i = first_zero;
 128                         break;
 129                 }
 130                 if (retval != ENOENT)
 131                         return EXT2_ET_INODE_ALLOC_FAIL;
 132                 i = upto + 1;
 133                 if (i > fs->super->s_inodes_count)
 134                         i = EXT2_FIRST_INODE(fs->super);
 135         } while (i != start_inode);
 136
 137         if (ext2fs_test_inode_bitmap2(map, i))
 138                 return EXT2_ET_INODE_ALLOC_FAIL;
 139         *ret = i;
 140         return 0;
 141 }
 142
 143 /*
 144  * Stupid algorithm --- we now just search forward starting from the
 145  * goal.  Should put in a smarter one someday....
 146  */
 147 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 148                            ext2fs_block_bitmap map, blk64_t *ret)
 149 {
 150         errcode_t retval;
 151         blk64_t b = 0;
 152         errcode_t (*gab)(ext2_filsys fs, blk64_t goal, blk64_t *ret);
 153
 154         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 155
 156         if (!map && fs->get_alloc_block) {
 157                 /*
 158                  * In case there are clients out there whose get_alloc_block
 159                  * handlers call ext2fs_new_block2 with a NULL block map,
 160                  * temporarily swap out the function pointer so that we don't
 161                  * end up in an infinite loop.
 162                  */
 163                 gab = fs->get_alloc_block;
 164                 fs->get_alloc_block = NULL;
 165                 retval = gab(fs, goal, &b);
 166                 fs->get_alloc_block = gab;
 167                 goto allocated;
 168         }
 169         if (!map)
 170                 map = fs->block_map;
 171         if (!map)
 172                 return EXT2_ET_NO_BLOCK_BITMAP;
 173         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 174                 goal = fs->super->s_first_data_block;
 175         goal &= ~EXT2FS_CLUSTER_MASK(fs);
 176
 177         retval = ext2fs_find_first_zero_block_bitmap2(map,
 178                         goal, ext2fs_blocks_count(fs->super) - 1, &b);
 179         if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
 180                 retval = ext2fs_find_first_zero_block_bitmap2(map,
 181                         fs->super->s_first_data_block, goal - 1, &b);
 182 allocated:
 183         if (retval == ENOENT)
 184                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 185         if (retval)
 186                 return retval;
 187
 188         ext2fs_clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
 189         *ret = b;
 190         return 0;
 191 }
 192
 193 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 194                            ext2fs_block_bitmap map, blk_t *ret)
 195 {
 196         errcode_t retval;
 197         blk64_t val;
 198         retval = ext2fs_new_block2(fs, goal, map, &val);
 199         if (!retval)
 200                 *ret = (blk_t) val;
 201         return retval;
 202 }
 203
 204 /*
 205  * This function zeros out the allocated block, and updates all of the
 206  * appropriate filesystem records.
 207  */
 208 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 209                              char *block_buf, blk64_t *ret)
 210 {
 211         errcode_t       retval;
 212         blk64_t         block;
 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         if (block_buf) {
 231                 memset(block_buf, 0, fs->blocksize);
 232                 retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 233         } else
 234                 retval = ext2fs_zero_blocks2(fs, block, 1, NULL, NULL);
 235         if (retval)
 236                 goto fail;
 237
 238         ext2fs_block_alloc_stats2(fs, block, +1);
 239         *ret = block;
 240
 241 fail:
 242         return retval;
 243 }
 244
 245 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 246                              char *block_buf, blk_t *ret)
 247 {
 248         errcode_t retval;
 249         blk64_t val;
 250         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 251         if (!retval)
 252                 *ret = (blk_t) val;
 253         return retval;
 254 }
 255
 256 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 257                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 258 {
 259         blk64_t b = start;
 260         int     c_ratio;
 261
 262         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 263
 264         if (!map)
 265                 map = fs->block_map;
 266         if (!map)
 267                 return EXT2_ET_NO_BLOCK_BITMAP;
 268         if (!b)
 269                 b = fs->super->s_first_data_block;
 270         if (!finish)
 271                 finish = start;
 272         if (!num)
 273                 num = 1;
 274         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 275         b &= ~(c_ratio - 1);
 276         finish &= ~(c_ratio -1);
 277         do {
 278                 if (b + num - 1 >= ext2fs_blocks_count(fs->super)) {
 279                         if (finish > start)
 280                                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 281                         b = fs->super->s_first_data_block;
 282                 }
 283                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 284                         *ret = b;
 285                         return 0;
 286                 }
 287                 b += c_ratio;
 288         } while (b != finish);
 289         return EXT2_ET_BLOCK_ALLOC_FAIL;
 290 }
 291
 292 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 293                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 294 {
 295         errcode_t retval;
 296         blk64_t val;
 297         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 298         if(!retval)
 299                 *ret = (blk_t) val;
 300         return retval;
 301 }
 302
 303 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 304                                      errcode_t (*func)(ext2_filsys fs,
 305                                                        blk64_t goal,
 306                                                        blk64_t *ret),
 307                                      errcode_t (**old)(ext2_filsys fs,
 308                                                        blk64_t goal,
 309                                                        blk64_t *ret))
 310 {
 311         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 312                 return;
 313
 314         if (old)
 315                 *old = fs->get_alloc_block;
 316
 317         fs->get_alloc_block = func;
 318 }
 319
 320 blk64_t ext2fs_find_inode_goal(ext2_filsys fs, ext2_ino_t ino,
 321                                struct ext2_inode *inode, blk64_t lblk)
 322 {
 323         dgrp_t                  group;
 324         __u8                    log_flex;
 325         struct ext2fs_extent    extent;
 326         ext2_extent_handle_t    handle = NULL;
 327         errcode_t               err;
 328
 329         if (inode == NULL || ext2fs_inode_data_blocks2(fs, inode) == 0)
 330                 goto no_blocks;
 331
 332         if (inode->i_flags & EXT4_INLINE_DATA_FL)
 333                 goto no_blocks;
 334
 335         if (inode->i_flags & EXT4_EXTENTS_FL) {
 336                 err = ext2fs_extent_open2(fs, ino, inode, &handle);
 337                 if (err)
 338                         goto no_blocks;
 339                 err = ext2fs_extent_goto2(handle, 0, lblk);
 340                 if (err)
 341                         goto no_blocks;
 342                 err = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
 343                 if (err)
 344                         goto no_blocks;
 345                 ext2fs_extent_free(handle);
 346                 return extent.e_pblk + (lblk - extent.e_lblk);
 347         }
 348
 349         /* block mapped file; see if block zero is mapped? */
 350         if (inode->i_block[0])
 351                 return inode->i_block[0];
 352
 353 no_blocks:
 354         ext2fs_extent_free(handle);
 355         log_flex = fs->super->s_log_groups_per_flex;
 356         group = ext2fs_group_of_ino(fs, ino);
 357         if (log_flex)
 358                 group = group & ~((1 << (log_flex)) - 1);
 359         return ext2fs_group_first_block2(fs, group);
 360 }
 361
 362 /*
 363  * Starting at _goal_, scan around the filesystem to find a run of free blocks
 364  * that's at least _len_ blocks long.  Possible flags:
 365  * - EXT2_NEWRANGE_EXACT_GOAL: The range of blocks must start at _goal_.
 366  * - EXT2_NEWRANGE_MIN_LENGTH: do not return a allocation shorter than _len_.
 367  * - EXT2_NEWRANGE_ZERO_BLOCKS: Zero blocks pblk to pblk+plen before returning.
 368  *
 369  * The starting block is returned in _pblk_ and the length is returned via
 370  * _plen_.  The blocks are not marked in the bitmap; the caller must mark
 371  * however much of the returned run they actually use, hopefully via
 372  * ext2fs_block_alloc_stats_range().
 373  *
 374  * This function can return a range that is longer than what was requested.
 375  */
 376 errcode_t ext2fs_new_range(ext2_filsys fs, int flags, blk64_t goal,
 377                            blk64_t len, ext2fs_block_bitmap map, blk64_t *pblk,
 378                            blk64_t *plen)
 379 {
 380         errcode_t retval;
 381         blk64_t start, end, b;
 382         int looped = 0;
 383         blk64_t max_blocks = ext2fs_blocks_count(fs->super);
 384         errcode_t (*nrf)(ext2_filsys fs, int flags, blk64_t goal,
 385                          blk64_t len, blk64_t *pblk, blk64_t *plen);
 386
 387         dbg_printf("%s: flags=0x%x goal=%llu len=%llu\n", __func__, flags,
 388                    goal, len);
 389         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 390         if (len == 0 || (flags & ~EXT2_NEWRANGE_ALL_FLAGS))
 391                 return EXT2_ET_INVALID_ARGUMENT;
 392
 393         if (!map && fs->new_range) {
 394                 /*
 395                  * In case there are clients out there whose new_range
 396                  * handlers call ext2fs_new_range with a NULL block map,
 397                  * temporarily swap out the function pointer so that we don't
 398                  * end up in an infinite loop.
 399                  */
 400                 nrf = fs->new_range;
 401                 fs->new_range = NULL;
 402                 retval = nrf(fs, flags, goal, len, pblk, plen);
 403                 fs->new_range = nrf;
 404                 if (retval)
 405                         return retval;
 406                 start = *pblk;
 407                 end = *pblk + *plen;
 408                 goto allocated;
 409         }
 410         if (!map)
 411                 map = fs->block_map;
 412         if (!map)
 413                 return EXT2_ET_NO_BLOCK_BITMAP;
 414         if (!goal || goal >= ext2fs_blocks_count(fs->super))
 415                 goal = fs->super->s_first_data_block;
 416
 417         start = goal;
 418         while (!looped || start <= goal) {
 419                 retval = ext2fs_find_first_zero_block_bitmap2(map, start,
 420                                                               max_blocks - 1,
 421                                                               &start);
 422                 if (retval == ENOENT) {
 423                         /*
 424                          * If there are no free blocks beyond the starting
 425                          * point, try scanning the whole filesystem, unless the
 426                          * user told us only to allocate from _goal_, or if
 427                          * we're already scanning the whole filesystem.
 428                          */
 429                         if (flags & EXT2_NEWRANGE_FIXED_GOAL ||
 430                             start == fs->super->s_first_data_block)
 431                                 goto fail;
 432                         start = fs->super->s_first_data_block;
 433                         continue;
 434                 } else if (retval)
 435                         goto errout;
 436
 437                 if (flags & EXT2_NEWRANGE_FIXED_GOAL && start != goal)
 438                         goto fail;
 439
 440                 b = min(start + len - 1, max_blocks - 1);
 441                 retval =  ext2fs_find_first_set_block_bitmap2(map, start, b,
 442                                                               &end);
 443                 if (retval == ENOENT)
 444                         end = b + 1;
 445                 else if (retval)
 446                         goto errout;
 447
 448                 if (!(flags & EXT2_NEWRANGE_MIN_LENGTH) ||
 449                     (end - start) >= len) {
 450                         /* Success! */
 451                         *pblk = start;
 452                         *plen = end - start;
 453                         dbg_printf("%s: new_range goal=%llu--%llu "
 454                                    "blk=%llu--%llu %llu\n",
 455                                    __func__, goal, goal + len - 1,
 456                                    *pblk, *pblk + *plen - 1, *plen);
 457 allocated:
 458                         for (b = start; b < end;
 459                              b += fs->super->s_blocks_per_group)
 460                                 ext2fs_clear_block_uninit(fs,
 461                                                 ext2fs_group_of_blk2(fs, b));
 462                         return 0;
 463                 }
 464
 465                 if (flags & EXT2_NEWRANGE_FIXED_GOAL)
 466                         goto fail;
 467                 start = end;
 468                 if (start >= max_blocks) {
 469                         if (looped)
 470                                 goto fail;
 471                         looped = 1;
 472                         start = fs->super->s_first_data_block;
 473                 }
 474         }
 475
 476 fail:
 477         retval = EXT2_ET_BLOCK_ALLOC_FAIL;
 478 errout:
 479         return retval;
 480 }
 481
 482 void ext2fs_set_new_range_callback(ext2_filsys fs,
 483         errcode_t (*func)(ext2_filsys fs, int flags, blk64_t goal,
 484                                blk64_t len, blk64_t *pblk, blk64_t *plen),
 485         errcode_t (**old)(ext2_filsys fs, int flags, blk64_t goal,
 486                                blk64_t len, blk64_t *pblk, blk64_t *plen))
 487 {
 488         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 489                 return;
 490
 491         if (old)
 492                 *old = fs->new_range;
 493
 494         fs->new_range = func;
 495 }
 496
 497 errcode_t ext2fs_alloc_range(ext2_filsys fs, int flags, blk64_t goal,
 498                              blk_t len, blk64_t *ret)
 499 {
 500         int newr_flags = EXT2_NEWRANGE_MIN_LENGTH;
 501         errcode_t retval;
 502         blk64_t plen;
 503
 504         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 505         if (len == 0 || (flags & ~EXT2_ALLOCRANGE_ALL_FLAGS))
 506                 return EXT2_ET_INVALID_ARGUMENT;
 507
 508         if (flags & EXT2_ALLOCRANGE_FIXED_GOAL)
 509                 newr_flags |= EXT2_NEWRANGE_FIXED_GOAL;
 510
 511         retval = ext2fs_new_range(fs, newr_flags, goal, len, NULL, ret, &plen);
 512         if (retval)
 513                 return retval;
 514
 515         if (plen < len)
 516                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 517
 518         if (flags & EXT2_ALLOCRANGE_ZERO_BLOCKS) {
 519                 retval = ext2fs_zero_blocks2(fs, *ret, len, NULL, NULL);
 520                 if (retval)
 521                         return retval;
 522         }
 523
 524         ext2fs_block_alloc_stats_range(fs, *ret, len, +1);
 525         return retval;
 526 }