resize/resize2fs.c

   1 /*
   2  * resize2fs.c --- ext2 main routine
   3  *
   4  * Copyright (C) 1997, 1998 by Theodore Ts'o and
   5  *      PowerQuest, Inc.
   6  *
   7  * Copyright (C) 1999, 2000 by Theosore Ts'o
   8  *
   9  * %Begin-Header%
  10  * This file may be redistributed under the terms of the GNU Public
  11  * License.
  12  * %End-Header%
  13  */
  14
  15 /*
  16  * Resizing a filesystem consists of the following phases:
  17  *
  18  *      1.  Adjust superblock and write out new parts of the inode
  19  *              table
  20  *      2.  Determine blocks which need to be relocated, and copy the
  21  *              contents of blocks from their old locations to the new ones.
  22  *      3.  Scan the inode table, doing the following:
  23  *              a.  If blocks have been moved, update the block
  24  *                      pointers in the inodes and indirect blocks to
  25  *                      point at the new block locations.
  26  *              b.  If parts of the inode table need to be evacuated,
  27  *                      copy inodes from their old locations to their
  28  *                      new ones.
  29  *              c.  If (b) needs to be done, note which blocks contain
  30  *                      directory information, since we will need to
  31  *                      update the directory information.
  32  *      4.  Update the directory blocks with the new inode locations.
  33  *      5.  Move the inode tables, if necessary.
  34  */
  35
  36 #include "config.h"
  37 #include "resize2fs.h"
  38 #include <time.h>
  39
  40 #ifdef __linux__                        /* Kludge for debugging */
  41 #define RESIZE2FS_DEBUG
  42 #endif
  43
  44 static void fix_uninit_block_bitmaps(ext2_filsys fs);
  45 static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size);
  46 static errcode_t blocks_to_move(ext2_resize_t rfs);
  47 static errcode_t block_mover(ext2_resize_t rfs);
  48 static errcode_t inode_scan_and_fix(ext2_resize_t rfs);
  49 static errcode_t inode_ref_fix(ext2_resize_t rfs);
  50 static errcode_t move_itables(ext2_resize_t rfs);
  51 static errcode_t fix_resize_inode(ext2_filsys fs);
  52 static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs);
  53 static errcode_t fix_sb_journal_backup(ext2_filsys fs);
  54 static errcode_t mark_table_blocks(ext2_filsys fs,
  55                                    ext2fs_block_bitmap bmap);
  56 static errcode_t clear_sparse_super2_last_group(ext2_resize_t rfs);
  57 static errcode_t reserve_sparse_super2_last_group(ext2_resize_t rfs,
  58                                                  ext2fs_block_bitmap meta_bmap);
  59 static errcode_t resize_group_descriptors(ext2_resize_t rfs, blk64_t new_size);
  60 static errcode_t move_bg_metadata(ext2_resize_t rfs);
  61 static errcode_t zero_high_bits_in_inodes(ext2_resize_t rfs);
  62
  63 /*
  64  * Some helper functions to check if a block is in a metadata area
  65  */
  66 static inline int is_block_bm(ext2_filsys fs, unsigned int grp, blk64_t blk)
  67 {
  68         return blk == ext2fs_block_bitmap_loc(fs, grp);
  69 }
  70
  71 static inline int is_inode_bm(ext2_filsys fs, unsigned int grp, blk64_t blk)
  72 {
  73         return blk == ext2fs_inode_bitmap_loc(fs, grp);
  74 }
  75
  76 static int is_inode_tb(ext2_filsys fs, unsigned int grp, blk64_t blk)
  77 {
  78         return blk >= ext2fs_inode_table_loc(fs, grp) &&
  79                blk < (ext2fs_inode_table_loc(fs, grp) +
  80                       fs->inode_blocks_per_group);
  81 }
  82
  83 /* Some bigalloc helper macros which are more succint... */
  84 #define B2C(x)  EXT2FS_B2C(fs, (x))
  85 #define C2B(x)  EXT2FS_C2B(fs, (x))
  86 #define EQ_CLSTR(x, y) (B2C(x) == B2C(y))
  87 #define LE_CLSTR(x, y) (B2C(x) <= B2C(y))
  88 #define LT_CLSTR(x, y) (B2C(x) <  B2C(y))
  89 #define GE_CLSTR(x, y) (B2C(x) >= B2C(y))
  90 #define GT_CLSTR(x, y) (B2C(x) >  B2C(y))
  91
  92 static int lazy_itable_init;
  93
  94 /*
  95  * This is the top-level routine which does the dirty deed....
  96  */
  97 errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
  98             errcode_t (*progress)(ext2_resize_t rfs, int pass,
  99                                           unsigned long cur,
 100                                           unsigned long max_val))
 101 {
 102         ext2_resize_t   rfs;
 103         errcode_t       retval;
 104         struct resource_track   rtrack, overall_track;
 105
 106         /*
 107          * Create the data structure
 108          */
 109         retval = ext2fs_get_mem(sizeof(struct ext2_resize_struct), &rfs);
 110         if (retval)
 111                 return retval;
 112
 113         memset(rfs, 0, sizeof(struct ext2_resize_struct));
 114         fs->priv_data = rfs;
 115         rfs->old_fs = fs;
 116         rfs->flags = flags;
 117         rfs->itable_buf  = 0;
 118         rfs->progress = progress;
 119
 120         init_resource_track(&overall_track, "overall resize2fs", fs->io);
 121         init_resource_track(&rtrack, "read_bitmaps", fs->io);
 122         retval = ext2fs_read_bitmaps(fs);
 123         if (retval)
 124                 goto errout;
 125         print_resource_track(rfs, &rtrack, fs->io);
 126
 127         fs->super->s_state |= EXT2_ERROR_FS;
 128         ext2fs_mark_super_dirty(fs);
 129         ext2fs_flush(fs);
 130
 131         init_resource_track(&rtrack, "fix_uninit_block_bitmaps 1", fs->io);
 132         fix_uninit_block_bitmaps(fs);
 133         print_resource_track(rfs, &rtrack, fs->io);
 134         retval = ext2fs_dup_handle(fs, &rfs->new_fs);
 135         if (retval)
 136                 goto errout;
 137
 138         init_resource_track(&rtrack, "resize_group_descriptors", fs->io);
 139         retval = resize_group_descriptors(rfs, *new_size);
 140         if (retval)
 141                 goto errout;
 142         print_resource_track(rfs, &rtrack, fs->io);
 143
 144         init_resource_track(&rtrack, "move_bg_metadata", fs->io);
 145         retval = move_bg_metadata(rfs);
 146         if (retval)
 147                 goto errout;
 148         print_resource_track(rfs, &rtrack, fs->io);
 149
 150         init_resource_track(&rtrack, "zero_high_bits_in_metadata", fs->io);
 151         retval = zero_high_bits_in_inodes(rfs);
 152         if (retval)
 153                 goto errout;
 154         print_resource_track(rfs, &rtrack, fs->io);
 155
 156         init_resource_track(&rtrack, "adjust_superblock", fs->io);
 157         retval = adjust_superblock(rfs, *new_size);
 158         if (retval)
 159                 goto errout;
 160         print_resource_track(rfs, &rtrack, fs->io);
 161
 162         init_resource_track(&rtrack, "fix_uninit_block_bitmaps 2", fs->io);
 163         fix_uninit_block_bitmaps(rfs->new_fs);
 164         print_resource_track(rfs, &rtrack, fs->io);
 165         /* Clear the block bitmap uninit flag for the last block group */
 166         ext2fs_bg_flags_clear(rfs->new_fs, rfs->new_fs->group_desc_count - 1,
 167                              EXT2_BG_BLOCK_UNINIT);
 168
 169         *new_size = ext2fs_blocks_count(rfs->new_fs->super);
 170
 171         init_resource_track(&rtrack, "blocks_to_move", fs->io);
 172         retval = blocks_to_move(rfs);
 173         if (retval)
 174                 goto errout;
 175         print_resource_track(rfs, &rtrack, fs->io);
 176
 177 #ifdef RESIZE2FS_DEBUG
 178         if (rfs->flags & RESIZE_DEBUG_BMOVE)
 179                 printf("Number of free blocks: %llu/%llu, Needed: %llu\n",
 180                        ext2fs_free_blocks_count(rfs->old_fs->super),
 181                        ext2fs_free_blocks_count(rfs->new_fs->super),
 182                        rfs->needed_blocks);
 183 #endif
 184
 185         init_resource_track(&rtrack, "block_mover", fs->io);
 186         retval = block_mover(rfs);
 187         if (retval)
 188                 goto errout;
 189         print_resource_track(rfs, &rtrack, fs->io);
 190
 191         init_resource_track(&rtrack, "inode_scan_and_fix", fs->io);
 192         retval = inode_scan_and_fix(rfs);
 193         if (retval)
 194                 goto errout;
 195         print_resource_track(rfs, &rtrack, fs->io);
 196
 197         init_resource_track(&rtrack, "inode_ref_fix", fs->io);
 198         retval = inode_ref_fix(rfs);
 199         if (retval)
 200                 goto errout;
 201         print_resource_track(rfs, &rtrack, fs->io);
 202
 203         init_resource_track(&rtrack, "move_itables", fs->io);
 204         retval = move_itables(rfs);
 205         if (retval)
 206                 goto errout;
 207         print_resource_track(rfs, &rtrack, fs->io);
 208
 209         retval = clear_sparse_super2_last_group(rfs);
 210         if (retval)
 211                 goto errout;
 212
 213         init_resource_track(&rtrack, "calculate_summary_stats", fs->io);
 214         retval = ext2fs_calculate_summary_stats(rfs->new_fs);
 215         if (retval)
 216                 goto errout;
 217         print_resource_track(rfs, &rtrack, fs->io);
 218
 219         init_resource_track(&rtrack, "fix_resize_inode", fs->io);
 220         retval = fix_resize_inode(rfs->new_fs);
 221         if (retval)
 222                 goto errout;
 223         print_resource_track(rfs, &rtrack, fs->io);
 224
 225         init_resource_track(&rtrack, "fix_sb_journal_backup", fs->io);
 226         retval = fix_sb_journal_backup(rfs->new_fs);
 227         if (retval)
 228                 goto errout;
 229         print_resource_track(rfs, &rtrack, fs->io);
 230
 231         retval = ext2fs_set_gdt_csum(rfs->new_fs);
 232         if (retval)
 233                 goto errout;
 234
 235         rfs->new_fs->super->s_state &= ~EXT2_ERROR_FS;
 236         rfs->new_fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;
 237
 238         print_resource_track(rfs, &overall_track, fs->io);
 239         retval = ext2fs_close_free(&rfs->new_fs);
 240         if (retval)
 241                 goto errout;
 242
 243         rfs->flags = flags;
 244
 245         ext2fs_free(rfs->old_fs);
 246         rfs->old_fs = NULL;
 247         if (rfs->itable_buf)
 248                 ext2fs_free_mem(&rfs->itable_buf);
 249         if (rfs->reserve_blocks)
 250                 ext2fs_free_block_bitmap(rfs->reserve_blocks);
 251         if (rfs->move_blocks)
 252                 ext2fs_free_block_bitmap(rfs->move_blocks);
 253         ext2fs_free_mem(&rfs);
 254
 255         return 0;
 256
 257 errout:
 258         if (rfs->new_fs) {
 259                 ext2fs_free(rfs->new_fs);
 260                 rfs->new_fs = NULL;
 261         }
 262         if (rfs->itable_buf)
 263                 ext2fs_free_mem(&rfs->itable_buf);
 264         ext2fs_free_mem(&rfs);
 265         return retval;
 266 }
 267
 268 /* Keep the size of the group descriptor region constant */
 269 static void adjust_reserved_gdt_blocks(ext2_filsys old_fs, ext2_filsys fs)
 270 {
 271         if (ext2fs_has_feature_resize_inode(fs->super) &&
 272             (old_fs->desc_blocks != fs->desc_blocks)) {
 273                 int new;
 274
 275                 new = ((int) fs->super->s_reserved_gdt_blocks) +
 276                         (old_fs->desc_blocks - fs->desc_blocks);
 277                 if (new < 0)
 278                         new = 0;
 279                 if (new > (int) fs->blocksize/4)
 280                         new = fs->blocksize/4;
 281                 fs->super->s_reserved_gdt_blocks = new;
 282         }
 283 }
 284
 285 /* Toggle 64bit mode */
 286 static errcode_t resize_group_descriptors(ext2_resize_t rfs, blk64_t new_size)
 287 {
 288         void *o, *n, *new_group_desc;
 289         dgrp_t i;
 290         int copy_size;
 291         errcode_t retval;
 292
 293         if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
 294                 return 0;
 295
 296         if (new_size != ext2fs_blocks_count(rfs->new_fs->super) ||
 297             ext2fs_blocks_count(rfs->new_fs->super) >= (1ULL << 32) ||
 298             (rfs->flags & RESIZE_DISABLE_64BIT &&
 299              rfs->flags & RESIZE_ENABLE_64BIT))
 300                 return EXT2_ET_INVALID_ARGUMENT;
 301
 302         if (rfs->flags & RESIZE_DISABLE_64BIT) {
 303                 ext2fs_clear_feature_64bit(rfs->new_fs->super);
 304                 rfs->new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE;
 305         } else if (rfs->flags & RESIZE_ENABLE_64BIT) {
 306                 ext2fs_set_feature_64bit(rfs->new_fs->super);
 307                 rfs->new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
 308         }
 309
 310         if (EXT2_DESC_SIZE(rfs->old_fs->super) ==
 311             EXT2_DESC_SIZE(rfs->new_fs->super))
 312                 return 0;
 313
 314         o = rfs->new_fs->group_desc;
 315         rfs->new_fs->desc_blocks = ext2fs_div_ceil(
 316                         rfs->old_fs->group_desc_count,
 317                         EXT2_DESC_PER_BLOCK(rfs->new_fs->super));
 318         retval = ext2fs_get_arrayzero(rfs->new_fs->desc_blocks,
 319                                       rfs->old_fs->blocksize, &new_group_desc);
 320         if (retval)
 321                 return retval;
 322
 323         n = new_group_desc;
 324
 325         if (EXT2_DESC_SIZE(rfs->old_fs->super) <=
 326             EXT2_DESC_SIZE(rfs->new_fs->super))
 327                 copy_size = EXT2_DESC_SIZE(rfs->old_fs->super);
 328         else
 329                 copy_size = EXT2_DESC_SIZE(rfs->new_fs->super);
 330         for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
 331                 memcpy(n, o, copy_size);
 332                 n = (char *)n + EXT2_DESC_SIZE(rfs->new_fs->super);
 333                 o = (char *)o + EXT2_DESC_SIZE(rfs->old_fs->super);
 334         }
 335
 336         ext2fs_free_mem(&rfs->new_fs->group_desc);
 337         rfs->new_fs->group_desc = new_group_desc;
 338
 339         for (i = 0; i < rfs->old_fs->group_desc_count; i++)
 340                 ext2fs_group_desc_csum_set(rfs->new_fs, i);
 341
 342         adjust_reserved_gdt_blocks(rfs->old_fs, rfs->new_fs);
 343
 344         return 0;
 345 }
 346
 347 /* Move bitmaps/inode tables out of the way. */
 348 static errcode_t move_bg_metadata(ext2_resize_t rfs)
 349 {
 350         dgrp_t i;
 351         blk64_t b, c, d, old_desc_blocks, new_desc_blocks, j;
 352         ext2fs_block_bitmap old_map, new_map;
 353         int old, new;
 354         errcode_t retval;
 355         int cluster_ratio;
 356
 357         if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
 358                 return 0;
 359
 360         retval = ext2fs_allocate_block_bitmap(rfs->old_fs, "oldfs", &old_map);
 361         if (retval)
 362                 return retval;
 363
 364         retval = ext2fs_allocate_block_bitmap(rfs->new_fs, "newfs", &new_map);
 365         if (retval)
 366                 goto out;
 367
 368         if (ext2fs_has_feature_meta_bg(rfs->old_fs->super)) {
 369                 old_desc_blocks = rfs->old_fs->super->s_first_meta_bg;
 370                 new_desc_blocks = rfs->new_fs->super->s_first_meta_bg;
 371         } else {
 372                 old_desc_blocks = rfs->old_fs->desc_blocks +
 373                                 rfs->old_fs->super->s_reserved_gdt_blocks;
 374                 new_desc_blocks = rfs->new_fs->desc_blocks +
 375                                 rfs->new_fs->super->s_reserved_gdt_blocks;
 376         }
 377
 378         /* Construct bitmaps of super/descriptor blocks in old and new fs */
 379         for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
 380                 retval = ext2fs_super_and_bgd_loc2(rfs->old_fs, i, &b, &c, &d,
 381                                                    NULL);
 382                 if (retval)
 383                         goto out;
 384                 if (b)
 385                         ext2fs_mark_block_bitmap2(old_map, b);
 386                 for (j = 0; c != 0 && j < old_desc_blocks; j++)
 387                         ext2fs_mark_block_bitmap2(old_map, c + j);
 388                 if (d)
 389                         ext2fs_mark_block_bitmap2(old_map, d);
 390
 391                 retval = ext2fs_super_and_bgd_loc2(rfs->new_fs, i, &b, &c, &d,
 392                                                    NULL);
 393                 if (retval)
 394                         goto out;
 395                 if (b)
 396                         ext2fs_mark_block_bitmap2(new_map, b);
 397                 for (j = 0; c != 0 && j < new_desc_blocks; j++)
 398                         ext2fs_mark_block_bitmap2(new_map, c + j);
 399                 if (d)
 400                         ext2fs_mark_block_bitmap2(new_map, d);
 401         }
 402
 403         cluster_ratio = EXT2FS_CLUSTER_RATIO(rfs->new_fs);
 404
 405         /* Find changes in block allocations for bg metadata */
 406         for (b = EXT2FS_B2C(rfs->old_fs,
 407                             rfs->old_fs->super->s_first_data_block);
 408              b < ext2fs_blocks_count(rfs->new_fs->super);
 409              b += cluster_ratio) {
 410                 old = ext2fs_test_block_bitmap2(old_map, b);
 411                 new = ext2fs_test_block_bitmap2(new_map, b);
 412
 413                 if (old && !new) {
 414                         /* mark old_map, unmark new_map */
 415                         if (cluster_ratio == 1)
 416                                 ext2fs_unmark_block_bitmap2(
 417                                                 rfs->new_fs->block_map, b);
 418                 } else if (!old && new)
 419                         ; /* unmark old_map, mark new_map */
 420                 else {
 421                         ext2fs_unmark_block_bitmap2(old_map, b);
 422                         ext2fs_unmark_block_bitmap2(new_map, b);
 423                 }
 424         }
 425
 426         /*
 427          * new_map now shows blocks that have been newly allocated.
 428          * old_map now shows blocks that have been newly freed.
 429          */
 430
 431         /*
 432          * Move any conflicting bitmaps and inode tables.  Ensure that we
 433          * don't try to free clusters associated with bitmaps or tables.
 434          */
 435         for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
 436                 b = ext2fs_block_bitmap_loc(rfs->new_fs, i);
 437                 if (ext2fs_test_block_bitmap2(new_map, b))
 438                         ext2fs_block_bitmap_loc_set(rfs->new_fs, i, 0);
 439                 else if (ext2fs_test_block_bitmap2(old_map, b))
 440                         ext2fs_unmark_block_bitmap2(old_map, b);
 441
 442                 b = ext2fs_inode_bitmap_loc(rfs->new_fs, i);
 443                 if (ext2fs_test_block_bitmap2(new_map, b))
 444                         ext2fs_inode_bitmap_loc_set(rfs->new_fs, i, 0);
 445                 else if (ext2fs_test_block_bitmap2(old_map, b))
 446                         ext2fs_unmark_block_bitmap2(old_map, b);
 447
 448                 c = ext2fs_inode_table_loc(rfs->new_fs, i);
 449                 for (b = 0;
 450                      b < rfs->new_fs->inode_blocks_per_group;
 451                      b++) {
 452                         if (ext2fs_test_block_bitmap2(new_map, b + c))
 453                                 ext2fs_inode_table_loc_set(rfs->new_fs, i, 0);
 454                         else if (ext2fs_test_block_bitmap2(old_map, b + c))
 455                                 ext2fs_unmark_block_bitmap2(old_map, b + c);
 456                 }
 457         }
 458
 459         /* Free unused clusters */
 460         for (b = 0;
 461              cluster_ratio > 1 && b < ext2fs_blocks_count(rfs->new_fs->super);
 462              b += cluster_ratio)
 463                 if (ext2fs_test_block_bitmap2(old_map, b))
 464                         ext2fs_unmark_block_bitmap2(rfs->new_fs->block_map, b);
 465 out:
 466         if (old_map)
 467                 ext2fs_free_block_bitmap(old_map);
 468         if (new_map)
 469                 ext2fs_free_block_bitmap(new_map);
 470         return retval;
 471 }
 472
 473 /* Zero out the high bits of extent fields */
 474 static errcode_t zero_high_bits_in_extents(ext2_filsys fs, ext2_ino_t ino,
 475                                  struct ext2_inode *inode)
 476 {
 477         ext2_extent_handle_t    handle;
 478         struct ext2fs_extent    extent;
 479         int                     op = EXT2_EXTENT_ROOT;
 480         errcode_t               errcode;
 481
 482         if (!(inode->i_flags & EXT4_EXTENTS_FL))
 483                 return 0;
 484
 485         errcode = ext2fs_extent_open(fs, ino, &handle);
 486         if (errcode)
 487                 return errcode;
 488
 489         while (1) {
 490                 errcode = ext2fs_extent_get(handle, op, &extent);
 491                 if (errcode)
 492                         break;
 493
 494                 op = EXT2_EXTENT_NEXT_SIB;
 495
 496                 if (extent.e_pblk > (1ULL << 32)) {
 497                         extent.e_pblk &= (1ULL << 32) - 1;
 498                         errcode = ext2fs_extent_replace(handle, 0, &extent);
 499                         if (errcode)
 500                                 break;
 501                 }
 502         }
 503
 504         /* Ok if we run off the end */
 505         if (errcode == EXT2_ET_EXTENT_NO_NEXT)
 506                 errcode = 0;
 507         ext2fs_extent_free(handle);
 508         return errcode;
 509 }
 510
 511 /* Zero out the high bits of inodes. */
 512 static errcode_t zero_high_bits_in_inodes(ext2_resize_t rfs)
 513 {
 514         ext2_filsys     fs = rfs->old_fs;
 515         int length = EXT2_INODE_SIZE(fs->super);
 516         struct ext2_inode *inode = NULL;
 517         ext2_inode_scan scan = NULL;
 518         errcode_t       retval;
 519         ext2_ino_t      ino;
 520
 521         if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
 522                 return 0;
 523
 524         if (fs->super->s_creator_os == EXT2_OS_HURD)
 525                 return 0;
 526
 527         retval = ext2fs_open_inode_scan(fs, 0, &scan);
 528         if (retval)
 529                 return retval;
 530
 531         retval = ext2fs_get_mem(length, &inode);
 532         if (retval)
 533                 goto out;
 534
 535         do {
 536                 retval = ext2fs_get_next_inode_full(scan, &ino, inode, length);
 537                 if (retval)
 538                         goto out;
 539                 if (!ino)
 540                         break;
 541                 if (!ext2fs_test_inode_bitmap2(fs->inode_map, ino))
 542                         continue;
 543
 544                 /*
 545                  * Here's how we deal with high block number fields:
 546                  *
 547                  *  - i_size_high has been been written out with i_size_lo
 548                  *    since the ext2 days, so no conversion is needed.
 549                  *
 550                  *  - i_blocks_hi is guarded by both the huge_file feature and
 551                  *    inode flags and has always been written out with
 552                  *    i_blocks_lo if the feature is set.  The field is only
 553                  *    ever read if both feature and inode flag are set, so
 554                  *    we don't need to zero it now.
 555                  *
 556                  *  - i_file_acl_high can be uninitialized, so zero it if
 557                  *    it isn't already.
 558                  */
 559                 if (inode->osd2.linux2.l_i_file_acl_high) {
 560                         inode->osd2.linux2.l_i_file_acl_high = 0;
 561                         retval = ext2fs_write_inode_full(fs, ino, inode,
 562                                                          length);
 563                         if (retval)
 564                                 goto out;
 565                 }
 566
 567                 retval = zero_high_bits_in_extents(fs, ino, inode);
 568                 if (retval)
 569                         goto out;
 570         } while (ino);
 571
 572 out:
 573         if (inode)
 574                 ext2fs_free_mem(&inode);
 575         if (scan)
 576                 ext2fs_close_inode_scan(scan);
 577         return retval;
 578 }
 579
 580 /*
 581  * Clean up the bitmaps for unitialized bitmaps
 582  */
 583 static void fix_uninit_block_bitmaps(ext2_filsys fs)
 584 {
 585         blk64_t         blk, lblk;
 586         dgrp_t          g;
 587         unsigned int    i;
 588
 589         if (!ext2fs_has_group_desc_csum(fs))
 590                 return;
 591
 592         for (g=0; g < fs->group_desc_count; g++) {
 593                 if (!(ext2fs_bg_flags_test(fs, g, EXT2_BG_BLOCK_UNINIT)))
 594                         continue;
 595
 596                 blk = ext2fs_group_first_block2(fs, g);
 597                 lblk = ext2fs_group_last_block2(fs, g);
 598                 ext2fs_unmark_block_bitmap_range2(fs->block_map, blk,
 599                                                   lblk - blk + 1);
 600
 601                 ext2fs_reserve_super_and_bgd(fs, g, fs->block_map);
 602                 ext2fs_mark_block_bitmap2(fs->block_map,
 603                                           ext2fs_block_bitmap_loc(fs, g));
 604                 ext2fs_mark_block_bitmap2(fs->block_map,
 605                                           ext2fs_inode_bitmap_loc(fs, g));
 606                 for (i = 0, blk = ext2fs_inode_table_loc(fs, g);
 607                      i < fs->inode_blocks_per_group;
 608                      i++, blk++)
 609                         ext2fs_mark_block_bitmap2(fs->block_map, blk);
 610         }
 611 }
 612
 613 /* --------------------------------------------------------------------
 614  *
 615  * Resize processing, phase 1.
 616  *
 617  * In this phase we adjust the in-memory superblock information, and
 618  * initialize any new parts of the inode table.  The new parts of the
 619  * inode table are created in virgin disk space, so we can abort here
 620  * without any side effects.
 621  * --------------------------------------------------------------------
 622  */
 623
 624 /*
 625  * If the group descriptor's bitmap and inode table blocks are valid,
 626  * release them in the new filesystem data structure, and mark them as
 627  * reserved so the old inode table blocks don't get overwritten.
 628  */
 629 static errcode_t free_gdp_blocks(ext2_filsys fs,
 630                                  ext2fs_block_bitmap reserve_blocks,
 631                                  ext2_filsys old_fs,
 632                                  dgrp_t group)
 633 {
 634         blk64_t         blk;
 635         unsigned int    j;
 636         dgrp_t          i;
 637         ext2fs_block_bitmap bg_map = NULL;
 638         errcode_t       retval = 0;
 639         dgrp_t          count = old_fs->group_desc_count - fs->group_desc_count;
 640
 641         /* If bigalloc, don't free metadata living in the same cluster */
 642         if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
 643                 retval = ext2fs_allocate_block_bitmap(fs, "bgdata", &bg_map);
 644                 if (retval)
 645                         goto out;
 646
 647                 retval = mark_table_blocks(fs, bg_map);
 648                 if (retval)
 649                         goto out;
 650         }
 651
 652         for (i = group; i < group + count; i++) {
 653                 blk = ext2fs_block_bitmap_loc(old_fs, i);
 654                 if (blk &&
 655                     (blk < ext2fs_blocks_count(fs->super)) &&
 656                     !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
 657                         ext2fs_block_alloc_stats2(fs, blk, -1);
 658                         ext2fs_mark_block_bitmap2(reserve_blocks, blk);
 659                 }
 660
 661                 blk = ext2fs_inode_bitmap_loc(old_fs, i);
 662                 if (blk &&
 663                     (blk < ext2fs_blocks_count(fs->super)) &&
 664                     !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
 665                         ext2fs_block_alloc_stats2(fs, blk, -1);
 666                         ext2fs_mark_block_bitmap2(reserve_blocks, blk);
 667                 }
 668
 669                 blk = ext2fs_inode_table_loc(old_fs, i);
 670                 for (j = 0;
 671                      j < fs->inode_blocks_per_group; j++, blk++) {
 672                         if (blk >= ext2fs_blocks_count(fs->super) ||
 673                             (bg_map && ext2fs_test_block_bitmap2(bg_map, blk)))
 674                                 continue;
 675                         ext2fs_block_alloc_stats2(fs, blk, -1);
 676                         ext2fs_mark_block_bitmap2(reserve_blocks, blk);
 677                 }
 678         }
 679
 680 out:
 681         if (bg_map)
 682                 ext2fs_free_block_bitmap(bg_map);
 683         return retval;
 684 }
 685
 686 /*
 687  * This routine is shared by the online and offline resize routines.
 688  * All of the information which is adjusted in memory is done here.
 689  */
 690 errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
 691                          ext2fs_block_bitmap reserve_blocks, blk64_t new_size)
 692 {
 693         errcode_t       retval;
 694         blk64_t         overhead = 0;
 695         blk64_t         rem;
 696         blk64_t         blk, group_block;
 697         blk64_t         real_end;
 698         blk64_t         old_numblocks, numblocks, adjblocks;
 699         unsigned long   i, j, old_desc_blocks;
 700         unsigned int    meta_bg, meta_bg_size;
 701         int             has_super, csum_flag, has_bg;
 702         unsigned long long new_inodes;  /* u64 to check for overflow */
 703         double          percent;
 704
 705         ext2fs_blocks_count_set(fs->super, new_size);
 706
 707 retry:
 708         fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
 709                                        fs->super->s_first_data_block,
 710                                        EXT2_BLOCKS_PER_GROUP(fs->super));
 711         if (fs->group_desc_count == 0)
 712                 return EXT2_ET_TOOSMALL;
 713         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 714                                           EXT2_DESC_PER_BLOCK(fs->super));
 715
 716         /*
 717          * Overhead is the number of bookkeeping blocks per group.  It
 718          * includes the superblock backup, the group descriptor
 719          * backups, the inode bitmap, the block bitmap, and the inode
 720          * table.
 721          */
 722         overhead = (int) (2 + fs->inode_blocks_per_group);
 723
 724         has_bg = 0;
 725         if (ext2fs_has_feature_sparse_super2(fs->super)) {
 726                 /*
 727                  * We have to do this manually since
 728                  * super->s_backup_bgs hasn't been set up yet.
 729                  */
 730                 if (fs->group_desc_count == 2)
 731                         has_bg = fs->super->s_backup_bgs[0] != 0;
 732                 else
 733                         has_bg = fs->super->s_backup_bgs[1] != 0;
 734         } else
 735                 has_bg = ext2fs_bg_has_super(fs, fs->group_desc_count - 1);
 736         if (has_bg)
 737                 overhead += 1 + fs->desc_blocks +
 738                         fs->super->s_reserved_gdt_blocks;
 739
 740         /*
 741          * See if the last group is big enough to support the
 742          * necessary data structures.  If not, we need to get rid of
 743          * it.
 744          */
 745         rem = (ext2fs_blocks_count(fs->super) - fs->super->s_first_data_block) %
 746                 fs->super->s_blocks_per_group;
 747         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 748                 return EXT2_ET_TOOSMALL;
 749         if ((fs->group_desc_count > 1) && rem && (rem < overhead+50)) {
 750                 ext2fs_blocks_count_set(fs->super,
 751                                         ext2fs_blocks_count(fs->super) - rem);
 752                 goto retry;
 753         }
 754         /*
 755          * Adjust the number of inodes
 756          */
 757         new_inodes =(unsigned long long) fs->super->s_inodes_per_group * fs->group_desc_count;
 758         if (new_inodes > ~0U) {
 759                 fprintf(stderr, _("inodes (%llu) must be less than %u"),
 760                                    new_inodes, ~0U);
 761                 return EXT2_ET_TOO_MANY_INODES;
 762         }
 763         fs->super->s_inodes_count = fs->super->s_inodes_per_group *
 764                 fs->group_desc_count;
 765
 766         /*
 767          * Adjust the number of free blocks
 768          */
 769         blk = ext2fs_blocks_count(old_fs->super);
 770         if (blk > ext2fs_blocks_count(fs->super))
 771                 ext2fs_free_blocks_count_set(fs->super,
 772                         ext2fs_free_blocks_count(fs->super) -
 773                         (blk - ext2fs_blocks_count(fs->super)));
 774         else
 775                 ext2fs_free_blocks_count_set(fs->super,
 776                         ext2fs_free_blocks_count(fs->super) +
 777                         (ext2fs_blocks_count(fs->super) - blk));
 778
 779         /*
 780          * Adjust the number of reserved blocks
 781          */
 782         percent = (ext2fs_r_blocks_count(old_fs->super) * 100.0) /
 783                 ext2fs_blocks_count(old_fs->super);
 784         ext2fs_r_blocks_count_set(fs->super,
 785                                   (percent * ext2fs_blocks_count(fs->super) /
 786                                    100.0));
 787
 788         /*
 789          * Adjust the bitmaps for size
 790          */
 791         retval = ext2fs_resize_inode_bitmap2(fs->super->s_inodes_count,
 792                                             fs->super->s_inodes_count,
 793                                             fs->inode_map);
 794         if (retval) goto errout;
 795
 796         real_end = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count) - 1 +
 797                 fs->super->s_first_data_block;
 798         retval = ext2fs_resize_block_bitmap2(new_size - 1,
 799                                              real_end, fs->block_map);
 800         if (retval) goto errout;
 801
 802         /*
 803          * If we are growing the file system, also grow the size of
 804          * the reserve_blocks bitmap
 805          */
 806         if (reserve_blocks && new_size > ext2fs_blocks_count(old_fs->super)) {
 807                 retval = ext2fs_resize_block_bitmap2(new_size - 1,
 808                                                      real_end, reserve_blocks);
 809                 if (retval) goto errout;
 810         }
 811
 812         /*
 813          * Reallocate the group descriptors as necessary.
 814          */
 815         if (EXT2_DESC_SIZE(old_fs->super) == EXT2_DESC_SIZE(fs->super) &&
 816             old_fs->desc_blocks != fs->desc_blocks) {
 817                 retval = ext2fs_resize_mem(old_fs->desc_blocks *
 818                                            fs->blocksize,
 819                                            fs->desc_blocks * fs->blocksize,
 820                                            &fs->group_desc);
 821                 if (retval)
 822                         goto errout;
 823                 if (fs->desc_blocks > old_fs->desc_blocks)
 824                         memset((char *) fs->group_desc +
 825                                (old_fs->desc_blocks * fs->blocksize), 0,
 826                                (fs->desc_blocks - old_fs->desc_blocks) *
 827                                fs->blocksize);
 828         }
 829
 830         /*
 831          * If the resize_inode feature is set, and we are changing the
 832          * number of descriptor blocks, then adjust
 833          * s_reserved_gdt_blocks if possible to avoid needing to move
 834          * the inode table either now or in the future.
 835          *
 836          * Note: If we're converting to 64bit mode, we did this earlier.
 837          */
 838         if (EXT2_DESC_SIZE(old_fs->super) == EXT2_DESC_SIZE(fs->super))
 839                 adjust_reserved_gdt_blocks(old_fs, fs);
 840
 841         if (ext2fs_has_feature_meta_bg(fs->super) &&
 842             (fs->super->s_first_meta_bg > fs->desc_blocks)) {
 843                 ext2fs_clear_feature_meta_bg(fs->super);
 844                 fs->super->s_first_meta_bg = 0;
 845         }
 846
 847         /*
 848          * Update the location of the backup superblocks if the
 849          * sparse_super2 feature is enabled.
 850          */
 851         if (ext2fs_has_feature_sparse_super2(fs->super)) {
 852                 dgrp_t last_bg = fs->group_desc_count - 1;
 853                 dgrp_t old_last_bg = old_fs->group_desc_count - 1;
 854
 855                 if (last_bg > old_last_bg) {
 856                         if (old_fs->group_desc_count == 1)
 857                                 fs->super->s_backup_bgs[0] = 1;
 858                         if ((old_fs->group_desc_count < 3 &&
 859                              fs->group_desc_count > 2) ||
 860                             fs->super->s_backup_bgs[1])
 861                                 fs->super->s_backup_bgs[1] = last_bg;
 862                 } else if (last_bg < old_last_bg) {
 863                         if (fs->super->s_backup_bgs[0] > last_bg)
 864                                 fs->super->s_backup_bgs[0] = 0;
 865                         if (fs->super->s_backup_bgs[1] > last_bg)
 866                                 fs->super->s_backup_bgs[1] = 0;
 867                         if (last_bg > 1 &&
 868                             old_fs->super->s_backup_bgs[1] == old_last_bg)
 869                                 fs->super->s_backup_bgs[1] = last_bg;
 870                 }
 871         }
 872
 873         /*
 874          * If we are shrinking the number of block groups, we're done
 875          * and can exit now.
 876          */
 877         if (old_fs->group_desc_count > fs->group_desc_count) {
 878                 /*
 879                  * Check the block groups that we are chopping off
 880                  * and free any blocks associated with their metadata
 881                  */
 882                 retval = free_gdp_blocks(fs, reserve_blocks, old_fs,
 883                                          fs->group_desc_count);
 884                 goto errout;
 885         }
 886
 887         /*
 888          * Fix the count of the last (old) block group
 889          */
 890         old_numblocks = (ext2fs_blocks_count(old_fs->super) -
 891                          old_fs->super->s_first_data_block) %
 892                                  old_fs->super->s_blocks_per_group;
 893         if (!old_numblocks)
 894                 old_numblocks = old_fs->super->s_blocks_per_group;
 895         if (old_fs->group_desc_count == fs->group_desc_count) {
 896                 numblocks = (ext2fs_blocks_count(fs->super) -
 897                              fs->super->s_first_data_block) %
 898                         fs->super->s_blocks_per_group;
 899                 if (!numblocks)
 900                         numblocks = fs->super->s_blocks_per_group;
 901         } else
 902                 numblocks = fs->super->s_blocks_per_group;
 903         i = old_fs->group_desc_count - 1;
 904         ext2fs_bg_free_blocks_count_set(fs, i, ext2fs_bg_free_blocks_count(fs, i) + (numblocks - old_numblocks));
 905         ext2fs_group_desc_csum_set(fs, i);
 906
 907         /*
 908          * If the number of block groups is staying the same, we're
 909          * done and can exit now.  (If the number block groups is
 910          * shrinking, we had exited earlier.)
 911          */
 912         if (old_fs->group_desc_count >= fs->group_desc_count) {
 913                 retval = 0;
 914                 goto errout;
 915         }
 916
 917         /*
 918          * Initialize the new block group descriptors
 919          */
 920         group_block = ext2fs_group_first_block2(fs,
 921                                                 old_fs->group_desc_count);
 922         csum_flag = ext2fs_has_group_desc_csum(fs);
 923         if (!getenv("RESIZE2FS_FORCE_ITABLE_INIT") &&
 924             access("/sys/fs/ext4/features/lazy_itable_init", F_OK) == 0)
 925                 lazy_itable_init = 1;
 926         if (ext2fs_has_feature_meta_bg(fs->super))
 927                 old_desc_blocks = fs->super->s_first_meta_bg;
 928         else
 929                 old_desc_blocks = fs->desc_blocks +
 930                         fs->super->s_reserved_gdt_blocks;
 931
 932         /*
 933          * If we changed the number of block_group descriptor blocks,
 934          * we need to make sure they are all marked as reserved in the
 935          * file systems's block allocation map.
 936          */
 937         for (i = 0; i < old_fs->group_desc_count; i++)
 938                 ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 939
 940         for (i = old_fs->group_desc_count;
 941              i < fs->group_desc_count; i++) {
 942                 memset(ext2fs_group_desc(fs, fs->group_desc, i), 0,
 943                        sizeof(struct ext2_group_desc));
 944                 adjblocks = 0;
 945
 946                 ext2fs_bg_flags_zap(fs, i);
 947                 if (csum_flag) {
 948                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 949                         if (!lazy_itable_init)
 950                                 ext2fs_bg_flags_set(fs, i,
 951                                                     EXT2_BG_INODE_ZEROED);
 952                         ext2fs_bg_itable_unused_set(fs, i,
 953                                         fs->super->s_inodes_per_group);
 954                 }
 955
 956                 numblocks = ext2fs_group_blocks_count(fs, i);
 957                 if ((i < fs->group_desc_count - 1) && csum_flag)
 958                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 959
 960                 has_super = ext2fs_bg_has_super(fs, i);
 961                 if (has_super) {
 962                         ext2fs_block_alloc_stats2(fs, group_block, +1);
 963                         adjblocks++;
 964                 }
 965                 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 966                 meta_bg = i / meta_bg_size;
 967                 if (!ext2fs_has_feature_meta_bg(fs->super) ||
 968                     (meta_bg < fs->super->s_first_meta_bg)) {
 969                         if (has_super) {
 970                                 for (j=0; j < old_desc_blocks; j++)
 971                                         ext2fs_block_alloc_stats2(fs,
 972                                                  group_block + 1 + j, +1);
 973                                 adjblocks += old_desc_blocks;
 974                         }
 975                 } else {
 976                         if (has_super)
 977                                 has_super = 1;
 978                         if (((i % meta_bg_size) == 0) ||
 979                             ((i % meta_bg_size) == 1) ||
 980                             ((i % meta_bg_size) == (meta_bg_size-1)))
 981                                 ext2fs_block_alloc_stats2(fs,
 982                                                  group_block + has_super, +1);
 983                 }
 984
 985                 adjblocks += 2 + fs->inode_blocks_per_group;
 986
 987                 numblocks -= adjblocks;
 988                 ext2fs_free_blocks_count_set(fs->super,
 989                              ext2fs_free_blocks_count(fs->super) - adjblocks);
 990                 fs->super->s_free_inodes_count +=
 991                         fs->super->s_inodes_per_group;
 992                 ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
 993                 ext2fs_bg_free_inodes_count_set(fs, i,
 994                                                 fs->super->s_inodes_per_group);
 995                 ext2fs_bg_used_dirs_count_set(fs, i, 0);
 996                 ext2fs_group_desc_csum_set(fs, i);
 997
 998                 retval = ext2fs_allocate_group_table(fs, i, 0);
 999                 if (retval) goto errout;
1000
1001                 group_block += fs->super->s_blocks_per_group;
1002         }
1003         retval = 0;
1004
1005         /*
1006          * Mark all of the metadata blocks as reserved so they won't
1007          * get allocated by the call to ext2fs_allocate_group_table()
1008          * in blocks_to_move(), where we allocate new blocks to
1009          * replace those allocation bitmap and inode table blocks
1010          * which have to get relocated to make space for an increased
1011          * number of the block group descriptors.
1012          */
1013         if (reserve_blocks)
1014                 mark_table_blocks(fs, reserve_blocks);
1015
1016 errout:
1017         return (retval);
1018 }
1019
1020 /*
1021  * This routine adjusts the superblock and other data structures, both
1022  * in disk as well as in memory...
1023  */
1024 static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size)
1025 {
1026         ext2_filsys     fs = rfs->new_fs;
1027         int             adj = 0;
1028         errcode_t       retval;
1029         blk64_t         group_block;
1030         unsigned long   i;
1031         unsigned long   max_group;
1032
1033         ext2fs_mark_super_dirty(fs);
1034         ext2fs_mark_bb_dirty(fs);
1035         ext2fs_mark_ib_dirty(fs);
1036
1037         retval = ext2fs_allocate_block_bitmap(fs, _("reserved blocks"),
1038                                               &rfs->reserve_blocks);
1039         if (retval)
1040                 return retval;
1041
1042         retval = adjust_fs_info(fs, rfs->old_fs, rfs->reserve_blocks, new_size);
1043         if (retval)
1044                 goto errout;
1045
1046         /*
1047          * Check to make sure there are enough inodes
1048          */
1049         if ((rfs->old_fs->super->s_inodes_count -
1050              rfs->old_fs->super->s_free_inodes_count) >
1051             rfs->new_fs->super->s_inodes_count) {
1052                 retval = ENOSPC;
1053                 goto errout;
1054         }
1055
1056         /*
1057          * If we are shrinking the number block groups, we're done and
1058          * can exit now.
1059          */
1060         if (rfs->old_fs->group_desc_count > fs->group_desc_count) {
1061                 retval = 0;
1062                 goto errout;
1063         }
1064
1065         /*
1066          * If the number of block groups is staying the same, we're
1067          * done and can exit now.  (If the number block groups is
1068          * shrinking, we had exited earlier.)
1069          */
1070         if (rfs->old_fs->group_desc_count >= fs->group_desc_count) {
1071                 retval = 0;
1072                 goto errout;
1073         }
1074
1075         /*
1076          * If we are using uninit_bg (aka GDT_CSUM) and the kernel
1077          * supports lazy inode initialization, we can skip
1078          * initializing the inode table.
1079          */
1080         if (lazy_itable_init && ext2fs_has_group_desc_csum(fs)) {
1081                 retval = 0;
1082                 goto errout;
1083         }
1084
1085         /*
1086          * Initialize the inode table
1087          */
1088         retval = ext2fs_get_array(fs->blocksize, fs->inode_blocks_per_group,
1089                                 &rfs->itable_buf);
1090         if (retval)
1091                 goto errout;
1092
1093         memset(rfs->itable_buf, 0, fs->blocksize * fs->inode_blocks_per_group);
1094         group_block = ext2fs_group_first_block2(fs,
1095                                                 rfs->old_fs->group_desc_count);
1096         adj = rfs->old_fs->group_desc_count;
1097         max_group = fs->group_desc_count - adj;
1098         if (rfs->progress) {
1099                 retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
1100                                        0, max_group);
1101                 if (retval)
1102                         goto errout;
1103         }
1104         for (i = rfs->old_fs->group_desc_count;
1105              i < fs->group_desc_count; i++) {
1106                 /*
1107                  * Write out the new inode table
1108                  */
1109                 retval = ext2fs_zero_blocks2(fs, ext2fs_inode_table_loc(fs, i),
1110                                              fs->inode_blocks_per_group, NULL,
1111                                              NULL);
1112                 if (retval)
1113                         goto errout;
1114
1115                 io_channel_flush(fs->io);
1116                 if (rfs->progress) {
1117                         retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
1118                                                i - adj + 1, max_group);
1119                         if (retval)
1120                                 goto errout;
1121                 }
1122                 group_block += fs->super->s_blocks_per_group;
1123         }
1124         io_channel_flush(fs->io);
1125         retval = 0;
1126
1127 errout:
1128         return retval;
1129 }
1130
1131 /* --------------------------------------------------------------------
1132  *
1133  * Resize processing, phase 2.
1134  *
1135  * In this phase we adjust determine which blocks need to be moved, in
1136  * blocks_to_move().  We then copy the blocks to their ultimate new
1137  * destinations using block_mover().  Since we are copying blocks to
1138  * their new locations, again during this pass we can abort without
1139  * any problems.
1140  * --------------------------------------------------------------------
1141  */
1142
1143 /*
1144  * This helper function creates a block bitmap with all of the
1145  * filesystem meta-data blocks.
1146  */
1147 static errcode_t mark_table_blocks(ext2_filsys fs,
1148                                    ext2fs_block_bitmap bmap)
1149 {
1150         dgrp_t                  i;
1151         blk64_t                 blk;
1152
1153         for (i = 0; i < fs->group_desc_count; i++) {
1154                 ext2fs_reserve_super_and_bgd(fs, i, bmap);
1155
1156                 /*
1157                  * Mark the blocks used for the inode table
1158                  */
1159                 blk = ext2fs_inode_table_loc(fs, i);
1160                 if (blk)
1161                         ext2fs_mark_block_bitmap_range2(bmap, blk,
1162                                                 fs->inode_blocks_per_group);
1163
1164                 /*
1165                  * Mark block used for the block bitmap
1166                  */
1167                 blk = ext2fs_block_bitmap_loc(fs, i);
1168                 if (blk)
1169                         ext2fs_mark_block_bitmap2(bmap, blk);
1170
1171                 /*
1172                  * Mark block used for the inode bitmap
1173                  */
1174                 blk = ext2fs_inode_bitmap_loc(fs, i);
1175                 if (blk)
1176                         ext2fs_mark_block_bitmap2(bmap, blk);
1177         }
1178         return 0;
1179 }
1180
1181 /*
1182  * This function checks to see if a particular block (either a
1183  * superblock or a block group descriptor) overlaps with an inode or
1184  * block bitmap block, or with the inode table.
1185  */
1186 static void mark_fs_metablock(ext2_resize_t rfs,
1187                               ext2fs_block_bitmap meta_bmap,
1188                               int group, blk64_t blk)
1189 {
1190         ext2_filsys fs = rfs->new_fs;
1191
1192         ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
1193         ext2fs_block_alloc_stats2(fs, blk, +1);
1194
1195         /*
1196          * Check to see if we overlap with the inode or block bitmap,
1197          * or the inode tables.  If not, and the block is in use, then
1198          * mark it as a block to be moved.
1199          */
1200         if (is_block_bm(fs, group, blk)) {
1201                 ext2fs_block_bitmap_loc_set(fs, group, 0);
1202                 rfs->needed_blocks++;
1203                 return;
1204         }
1205         if (is_inode_bm(fs, group, blk)) {
1206                 ext2fs_inode_bitmap_loc_set(fs, group, 0);
1207                 rfs->needed_blocks++;
1208                 return;
1209         }
1210         if (is_inode_tb(fs, group, blk)) {
1211                 ext2fs_inode_table_loc_set(fs, group, 0);
1212                 rfs->needed_blocks++;
1213                 return;
1214         }
1215         if (ext2fs_has_feature_flex_bg(fs->super)) {
1216                 dgrp_t i;
1217
1218                 for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
1219                         if (is_block_bm(fs, i, blk)) {
1220                                 ext2fs_block_bitmap_loc_set(fs, i, 0);
1221                                 rfs->needed_blocks++;
1222                                 return;
1223                         }
1224                         if (is_inode_bm(fs, i, blk)) {
1225                                 ext2fs_inode_bitmap_loc_set(fs, i, 0);
1226                                 rfs->needed_blocks++;
1227                                 return;
1228                         }
1229                         if (is_inode_tb(fs, i, blk)) {
1230                                 ext2fs_inode_table_loc_set(fs, i, 0);
1231                                 rfs->needed_blocks++;
1232                                 return;
1233                         }
1234                 }
1235         }
1236
1237         if (ext2fs_has_group_desc_csum(fs) &&
1238             (ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT))) {
1239                 /*
1240                  * If the block bitmap is uninitialized, which means
1241                  * nothing other than standard metadata in use.
1242                  */
1243                 return;
1244         } else if (ext2fs_test_block_bitmap2(rfs->old_fs->block_map, blk) &&
1245                    !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
1246                 ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
1247                 rfs->needed_blocks++;
1248         }
1249 }
1250
1251
1252 /*
1253  * This routine marks and unmarks reserved blocks in the new block
1254  * bitmap.  It also determines which blocks need to be moved and
1255  * places this information into the move_blocks bitmap.
1256  */
1257 static errcode_t blocks_to_move(ext2_resize_t rfs)
1258 {
1259         unsigned int    j;
1260         int             has_super;
1261         dgrp_t          i, max_groups, g;
1262         blk64_t         blk, group_blk;
1263         blk64_t         old_blocks, new_blocks, group_end, cluster_freed;
1264         blk64_t         new_size;
1265         unsigned int    meta_bg, meta_bg_size;
1266         errcode_t       retval;
1267         ext2_filsys     fs, old_fs;
1268         ext2fs_block_bitmap     meta_bmap, new_meta_bmap = NULL;
1269         int             flex_bg;
1270
1271         fs = rfs->new_fs;
1272         old_fs = rfs->old_fs;
1273         if (ext2fs_blocks_count(old_fs->super) > ext2fs_blocks_count(fs->super))
1274                 fs = rfs->old_fs;
1275
1276         retval = ext2fs_allocate_block_bitmap(fs, _("blocks to be moved"),
1277                                               &rfs->move_blocks);
1278         if (retval)
1279                 return retval;
1280
1281         retval = ext2fs_allocate_block_bitmap(fs, _("meta-data blocks"),
1282                                               &meta_bmap);
1283         if (retval)
1284                 return retval;
1285
1286         retval = mark_table_blocks(old_fs, meta_bmap);
1287         if (retval)
1288                 return retval;
1289
1290         fs = rfs->new_fs;
1291
1292         /*
1293          * If we're shrinking the filesystem, we need to move any
1294          * group's metadata blocks (either allocation bitmaps or the
1295          * inode table) which are beyond the end of the new
1296          * filesystem.
1297          */
1298         new_size = ext2fs_blocks_count(fs->super);
1299         if (new_size < ext2fs_blocks_count(old_fs->super)) {
1300                 for (g = 0; g < fs->group_desc_count; g++) {
1301                         int realloc = 0;
1302                         /*
1303                          * ext2fs_allocate_group_table will re-allocate any
1304                          * metadata blocks whose location is set to zero.
1305                          */
1306                         if (ext2fs_block_bitmap_loc(fs, g) >= new_size) {
1307                                 ext2fs_block_bitmap_loc_set(fs, g, 0);
1308                                 realloc = 1;
1309                         }
1310                         if (ext2fs_inode_bitmap_loc(fs, g) >= new_size) {
1311                                 ext2fs_inode_bitmap_loc_set(fs, g, 0);
1312                                 realloc = 1;
1313                         }
1314                         if ((ext2fs_inode_table_loc(fs, g) +
1315                              fs->inode_blocks_per_group) > new_size) {
1316                                 ext2fs_inode_table_loc_set(fs, g, 0);
1317                                 realloc = 1;
1318                         }
1319
1320                         if (realloc) {
1321                                 retval = ext2fs_allocate_group_table(fs, g, 0);
1322                                 if (retval)
1323                                         return retval;
1324                         }
1325                 }
1326         }
1327
1328         /*
1329          * If we're shrinking the filesystem, we need to move all of
1330          * the blocks that don't fit any more
1331          */
1332         for (blk = ext2fs_blocks_count(fs->super);
1333              blk < ext2fs_blocks_count(old_fs->super); blk++) {
1334                 g = ext2fs_group_of_blk2(fs, blk);
1335                 if (ext2fs_has_group_desc_csum(fs) &&
1336                     ext2fs_bg_flags_test(old_fs, g, EXT2_BG_BLOCK_UNINIT)) {
1337                         /*
1338                          * The block bitmap is uninitialized, so skip
1339                          * to the next block group.
1340                          */
1341                         blk = ext2fs_group_first_block2(fs, g+1) - 1;
1342                         continue;
1343                 }
1344                 if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
1345                     !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
1346                         ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
1347                         rfs->needed_blocks++;
1348                 }
1349                 ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
1350         }
1351
1352         if (ext2fs_has_feature_meta_bg(old_fs->super))
1353                 old_blocks = old_fs->super->s_first_meta_bg;
1354         else
1355                 old_blocks = old_fs->desc_blocks +
1356                         old_fs->super->s_reserved_gdt_blocks;
1357         if (ext2fs_has_feature_meta_bg(fs->super))
1358                 new_blocks = fs->super->s_first_meta_bg;
1359         else
1360                 new_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
1361
1362         retval = reserve_sparse_super2_last_group(rfs, meta_bmap);
1363         if (retval)
1364                 goto errout;
1365
1366         if (EXT2_DESC_SIZE(rfs->old_fs->super) ==
1367             EXT2_DESC_SIZE(rfs->new_fs->super) &&
1368             old_blocks == new_blocks) {
1369                 retval = 0;
1370                 goto errout;
1371         }
1372
1373         max_groups = fs->group_desc_count;
1374         if (max_groups > old_fs->group_desc_count)
1375                 max_groups = old_fs->group_desc_count;
1376         group_blk = old_fs->super->s_first_data_block;
1377         /*
1378          * If we're reducing the number of descriptor blocks, this
1379          * makes life easy.  :-)   We just have to mark some extra
1380          * blocks as free.
1381          */
1382         if (old_blocks > new_blocks) {
1383                 if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
1384                         retval = ext2fs_allocate_block_bitmap(fs,
1385                                                         _("new meta blocks"),
1386                                                         &new_meta_bmap);
1387                         if (retval)
1388                                 goto errout;
1389
1390                         retval = mark_table_blocks(fs, new_meta_bmap);
1391                         if (retval)
1392                                 goto errout;
1393                 }
1394
1395                 for (i = 0; i < max_groups; i++) {
1396                         if (!ext2fs_bg_has_super(old_fs, i)) {
1397                                 group_blk += fs->super->s_blocks_per_group;
1398                                 continue;
1399                         }
1400                         group_end = group_blk + 1 + old_blocks;
1401                         for (blk = group_blk + 1 + new_blocks;
1402                              blk < group_end;) {
1403                                 if (new_meta_bmap == NULL ||
1404                                     !ext2fs_test_block_bitmap2(new_meta_bmap,
1405                                                                blk)) {
1406                                         cluster_freed =
1407                                                 EXT2FS_CLUSTER_RATIO(fs) -
1408                                                 (blk &
1409                                                  EXT2FS_CLUSTER_MASK(fs));
1410                                         if (cluster_freed > group_end - blk)
1411                                                 cluster_freed = group_end - blk;
1412                                         ext2fs_block_alloc_stats2(fs, blk, -1);
1413                                         blk += EXT2FS_CLUSTER_RATIO(fs);
1414                                         rfs->needed_blocks -= cluster_freed;
1415                                         continue;
1416                                 }
1417                                 rfs->needed_blocks--;
1418                                 blk++;
1419                         }
1420                         group_blk += fs->super->s_blocks_per_group;
1421                 }
1422                 retval = 0;
1423                 goto errout;
1424         }
1425         /*
1426          * If we're increasing the number of descriptor blocks, life
1427          * gets interesting....
1428          */
1429         meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
1430         flex_bg = ext2fs_has_feature_flex_bg(fs->super);
1431         /* first reserve all of the existing fs meta blocks */
1432         for (i = 0; i < max_groups; i++) {
1433                 has_super = ext2fs_bg_has_super(fs, i);
1434                 if (has_super)
1435                         mark_fs_metablock(rfs, meta_bmap, i, group_blk);
1436
1437                 meta_bg = i / meta_bg_size;
1438                 if (!ext2fs_has_feature_meta_bg(fs->super) ||
1439                     (meta_bg < fs->super->s_first_meta_bg)) {
1440                         if (has_super) {
1441                                 for (blk = group_blk+1;
1442                                      blk < group_blk + 1 + new_blocks; blk++)
1443                                         mark_fs_metablock(rfs, meta_bmap,
1444                                                           i, blk);
1445                         }
1446                 } else {
1447                         if (has_super)
1448                                 has_super = 1;
1449                         if (((i % meta_bg_size) == 0) ||
1450                             ((i % meta_bg_size) == 1) ||
1451                             ((i % meta_bg_size) == (meta_bg_size-1)))
1452                                 mark_fs_metablock(rfs, meta_bmap, i,
1453                                                   group_blk + has_super);
1454                 }
1455
1456                 /*
1457                  * Reserve the existing meta blocks that we know
1458                  * aren't to be moved.
1459                  *
1460                  * For flex_bg file systems, in order to avoid
1461                  * overwriting fs metadata (especially inode table
1462                  * blocks) belonging to a different block group when
1463                  * we are relocating the inode tables, we need to
1464                  * reserve all existing fs metadata blocks.
1465                  */
1466                 if (ext2fs_block_bitmap_loc(fs, i))
1467                         ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
1468                                  ext2fs_block_bitmap_loc(fs, i));
1469                 else if (flex_bg && i < old_fs->group_desc_count)
1470                         ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
1471                                  ext2fs_block_bitmap_loc(old_fs, i));
1472
1473                 if (ext2fs_inode_bitmap_loc(fs, i))
1474                         ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
1475                                  ext2fs_inode_bitmap_loc(fs, i));
1476                 else if (flex_bg && i < old_fs->group_desc_count)
1477                         ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
1478                                  ext2fs_inode_bitmap_loc(old_fs, i));
1479
1480                 if (ext2fs_inode_table_loc(fs, i))
1481                         ext2fs_mark_block_bitmap_range2(rfs->reserve_blocks,
1482                                         ext2fs_inode_table_loc(fs, i),
1483                                         fs->inode_blocks_per_group);
1484                 else if (flex_bg && i < old_fs->group_desc_count)
1485                         ext2fs_mark_block_bitmap_range2(rfs->reserve_blocks,
1486                                         ext2fs_inode_table_loc(old_fs, i),
1487                                         old_fs->inode_blocks_per_group);
1488
1489                 group_blk += rfs->new_fs->super->s_blocks_per_group;
1490         }
1491
1492         /* Allocate the missing data structures */
1493         for (i = 0; i < max_groups; i++) {
1494                 if (ext2fs_inode_table_loc(fs, i) &&
1495                     ext2fs_inode_bitmap_loc(fs, i) &&
1496                     ext2fs_block_bitmap_loc(fs, i))
1497                         continue;
1498
1499                 retval = ext2fs_allocate_group_table(fs, i,
1500                                                      rfs->reserve_blocks);
1501                 if (retval)
1502                         goto errout;
1503
1504                 /*
1505                  * For those structures that have changed, we need to
1506                  * do bookkeepping.
1507                  */
1508                 if (ext2fs_block_bitmap_loc(old_fs, i) !=
1509                     (blk = ext2fs_block_bitmap_loc(fs, i))) {
1510                         ext2fs_block_alloc_stats2(fs, blk, +1);
1511                         if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
1512                             !ext2fs_test_block_bitmap2(meta_bmap, blk))
1513                                 ext2fs_mark_block_bitmap2(rfs->move_blocks,
1514                                                          blk);
1515                 }
1516                 if (ext2fs_inode_bitmap_loc(old_fs, i) !=
1517                     (blk = ext2fs_inode_bitmap_loc(fs, i))) {
1518                         ext2fs_block_alloc_stats2(fs, blk, +1);
1519                         if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
1520                             !ext2fs_test_block_bitmap2(meta_bmap, blk))
1521                                 ext2fs_mark_block_bitmap2(rfs->move_blocks,
1522                                                          blk);
1523                 }
1524
1525                 /*
1526                  * The inode table, if we need to relocate it, is
1527                  * handled specially.  We have to reserve the blocks
1528                  * for both the old and the new inode table, since we
1529                  * can't have the inode table be destroyed during the
1530                  * block relocation phase.
1531                  */
1532                 if (ext2fs_inode_table_loc(fs, i) == ext2fs_inode_table_loc(old_fs, i))
1533                         continue;       /* inode table not moved */
1534
1535                 rfs->needed_blocks += fs->inode_blocks_per_group;
1536
1537                 /*
1538                  * Mark the new inode table as in use in the new block
1539                  * allocation bitmap, and move any blocks that might
1540                  * be necessary.
1541                  */
1542                 for (blk = ext2fs_inode_table_loc(fs, i), j=0;
1543                      j < fs->inode_blocks_per_group ; j++, blk++) {
1544                         ext2fs_block_alloc_stats2(fs, blk, +1);
1545                         if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
1546                             !ext2fs_test_block_bitmap2(meta_bmap, blk))
1547                                 ext2fs_mark_block_bitmap2(rfs->move_blocks,
1548                                                          blk);
1549                 }
1550
1551                 /*
1552                  * Make sure the old inode table is reserved in the
1553                  * block reservation bitmap.
1554                  */
1555                 for (blk = ext2fs_inode_table_loc(rfs->old_fs, i), j=0;
1556                      j < fs->inode_blocks_per_group ; j++, blk++)
1557                         ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
1558         }
1559         retval = 0;
1560
1561 errout:
1562         if (new_meta_bmap)
1563                 ext2fs_free_block_bitmap(new_meta_bmap);
1564         if (meta_bmap)
1565                 ext2fs_free_block_bitmap(meta_bmap);
1566
1567         return retval;
1568 }
1569
1570 /*
1571  * This helper function tries to allocate a new block.  We try to
1572  * avoid hitting the original group descriptor blocks at least at
1573  * first, since we want to make it possible to recover from a badly
1574  * aborted resize operation as much as possible.
1575  *
1576  * In the future, I may further modify this routine to balance out
1577  * where we get the new blocks across the various block groups.
1578  * Ideally we would allocate blocks that corresponded with the block
1579  * group of the containing inode, and keep contiguous blocks
1580  * together.  However, this very difficult to do efficiently, since we
1581  * don't have the necessary information up front.
1582  */
1583
1584 #define AVOID_OLD       1
1585 #define DESPERATION     2
1586
1587 static void init_block_alloc(ext2_resize_t rfs)
1588 {
1589         rfs->alloc_state = AVOID_OLD;
1590         rfs->new_blk = rfs->new_fs->super->s_first_data_block;
1591 #if 0
1592         /* HACK for testing */
1593         if (ext2fs_blocks_count(rfs->new_fs->super) >
1594             ext2fs_blocks_count(rfs->old_fs->super))
1595                 rfs->new_blk = ext2fs_blocks_count(rfs->old_fs->super);
1596 #endif
1597 }
1598
1599 static blk64_t get_new_block(ext2_resize_t rfs)
1600 {
1601         ext2_filsys     fs = rfs->new_fs;
1602
1603         while (1) {
1604                 if (rfs->new_blk >= ext2fs_blocks_count(fs->super)) {
1605                         if (rfs->alloc_state == DESPERATION)
1606                                 return 0;
1607
1608 #ifdef RESIZE2FS_DEBUG
1609                         if (rfs->flags & RESIZE_DEBUG_BMOVE)
1610                                 printf("Going into desperation mode "
1611                                        "for block allocations\n");
1612 #endif
1613                         rfs->alloc_state = DESPERATION;
1614                         rfs->new_blk = fs->super->s_first_data_block;
1615                         continue;
1616                 }
1617                 if (ext2fs_test_block_bitmap2(fs->block_map, rfs->new_blk) ||
1618                     ext2fs_test_block_bitmap2(rfs->reserve_blocks,
1619                                              rfs->new_blk) ||
1620                     ((rfs->alloc_state == AVOID_OLD) &&
1621                      (rfs->new_blk < ext2fs_blocks_count(rfs->old_fs->super)) &&
1622                      ext2fs_test_block_bitmap2(rfs->old_fs->block_map,
1623                                               rfs->new_blk))) {
1624                         rfs->new_blk++;
1625                         continue;
1626                 }
1627                 return rfs->new_blk;
1628         }
1629 }
1630
1631 static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
1632                                            blk64_t goal EXT2FS_ATTR((unused)),
1633                                            blk64_t *ret)
1634 {
1635         ext2_resize_t rfs = (ext2_resize_t) fs->priv_data;
1636         blk64_t blk;
1637         int group;
1638
1639         blk = get_new_block(rfs);
1640         if (!blk)
1641                 return ENOSPC;
1642
1643 #ifdef RESIZE2FS_DEBUG
1644         if (rfs->flags & 0xF)
1645                 printf("get_alloc_block allocating %llu\n", blk);
1646 #endif
1647
1648         ext2fs_mark_block_bitmap2(rfs->old_fs->block_map, blk);
1649         ext2fs_mark_block_bitmap2(rfs->new_fs->block_map, blk);
1650
1651         group = ext2fs_group_of_blk2(rfs->old_fs, blk);
1652         ext2fs_clear_block_uninit(rfs->old_fs, group);
1653         group = ext2fs_group_of_blk2(rfs->new_fs, blk);
1654         ext2fs_clear_block_uninit(rfs->new_fs, group);
1655
1656         *ret = (blk64_t) blk;
1657         return 0;
1658 }
1659
1660 static errcode_t block_mover(ext2_resize_t rfs)
1661 {
1662         blk64_t                 blk, old_blk, new_blk;
1663         ext2_filsys             fs = rfs->new_fs;
1664         ext2_filsys             old_fs = rfs->old_fs;
1665         errcode_t               retval;
1666         __u64                   c, size;
1667         int                     to_move, moved;
1668         ext2_badblocks_list     badblock_list = 0;
1669         int                     bb_modified = 0;
1670
1671         fs->get_alloc_block = resize2fs_get_alloc_block;
1672         old_fs->get_alloc_block = resize2fs_get_alloc_block;
1673
1674         retval = ext2fs_read_bb_inode(old_fs, &badblock_list);
1675         if (retval)
1676                 return retval;
1677
1678         new_blk = fs->super->s_first_data_block;
1679         if (!rfs->itable_buf) {
1680                 retval = ext2fs_get_array(fs->blocksize,
1681                                         fs->inode_blocks_per_group,
1682                                         &rfs->itable_buf);
1683                 if (retval)
1684                         return retval;
1685         }
1686         retval = ext2fs_create_extent_table(&rfs->bmap, 0);
1687         if (retval)
1688                 return retval;
1689
1690         /*
1691          * The first step is to figure out where all of the blocks
1692          * will go.
1693          */
1694         to_move = moved = 0;
1695         init_block_alloc(rfs);
1696         for (blk = B2C(old_fs->super->s_first_data_block);
1697              blk < ext2fs_blocks_count(old_fs->super);
1698              blk += EXT2FS_CLUSTER_RATIO(fs)) {
1699                 if (!ext2fs_test_block_bitmap2(old_fs->block_map, blk))
1700                         continue;
1701                 if (!ext2fs_test_block_bitmap2(rfs->move_blocks, blk))
1702                         continue;
1703                 if (ext2fs_badblocks_list_test(badblock_list, blk)) {
1704                         ext2fs_badblocks_list_del(badblock_list, blk);
1705                         bb_modified++;
1706                         continue;
1707                 }
1708
1709                 new_blk = get_new_block(rfs);
1710                 if (!new_blk) {
1711                         retval = ENOSPC;
1712                         goto errout;
1713                 }
1714                 ext2fs_block_alloc_stats2(fs, new_blk, +1);
1715                 ext2fs_add_extent_entry(rfs->bmap, B2C(blk), B2C(new_blk));
1716                 to_move++;
1717         }
1718
1719         if (to_move == 0) {
1720                 if (rfs->bmap) {
1721                         ext2fs_free_extent_table(rfs->bmap);
1722                         rfs->bmap = 0;
1723                 }
1724                 retval = 0;
1725                 goto errout;
1726         }
1727
1728         /*
1729          * Step two is to actually move the blocks
1730          */
1731         retval =  ext2fs_iterate_extent(rfs->bmap, 0, 0, 0);
1732         if (retval) goto errout;
1733
1734         if (rfs->progress) {
1735                 retval = (rfs->progress)(rfs, E2_RSZ_BLOCK_RELOC_PASS,
1736                                          0, to_move);
1737                 if (retval)
1738                         goto errout;
1739         }
1740         while (1) {
1741                 retval = ext2fs_iterate_extent(rfs->bmap, &old_blk, &new_blk, &size);
1742                 if (retval) goto errout;
1743                 if (!size)
1744                         break;
1745                 old_blk = C2B(old_blk);
1746                 new_blk = C2B(new_blk);
1747                 size = C2B(size);
1748 #ifdef RESIZE2FS_DEBUG
1749                 if (rfs->flags & RESIZE_DEBUG_BMOVE)
1750                         printf("Moving %llu blocks %llu->%llu\n",
1751                                size, old_blk, new_blk);
1752 #endif
1753                 do {
1754                         c = size;
1755                         if (c > fs->inode_blocks_per_group)
1756                                 c = fs->inode_blocks_per_group;
1757                         retval = io_channel_read_blk64(fs->io, old_blk, c,
1758                                                        rfs->itable_buf);
1759                         if (retval) goto errout;
1760                         retval = io_channel_write_blk64(fs->io, new_blk, c,
1761                                                         rfs->itable_buf);
1762                         if (retval) goto errout;
1763                         size -= c;
1764                         new_blk += c;
1765                         old_blk += c;
1766                         moved += c;
1767                         if (rfs->progress) {
1768                                 io_channel_flush(fs->io);
1769                                 retval = (rfs->progress)(rfs,
1770                                                 E2_RSZ_BLOCK_RELOC_PASS,
1771                                                 moved, to_move);
1772                                 if (retval)
1773                                         goto errout;
1774                         }
1775                 } while (size > 0);
1776                 io_channel_flush(fs->io);
1777         }
1778
1779 errout:
1780         if (badblock_list) {
1781                 if (!retval && bb_modified)
1782                         retval = ext2fs_update_bb_inode(old_fs,
1783                                                         badblock_list);
1784                 ext2fs_badblocks_list_free(badblock_list);
1785         }
1786         return retval;
1787 }
1788
1789
1790 /* --------------------------------------------------------------------
1791  *
1792  * Resize processing, phase 3
1793  *
1794  * --------------------------------------------------------------------
1795  */
1796
1797
1798 /*
1799  * The extent translation table is stored in clusters so we need to
1800  * take special care when mapping a source block number to its
1801  * destination block number.
1802  */
1803 static __u64 extent_translate(ext2_filsys fs, ext2_extent extent, __u64 old_loc)
1804 {
1805         __u64 new_block = C2B(ext2fs_extent_translate(extent, B2C(old_loc)));
1806
1807         if (new_block != 0)
1808                 new_block += old_loc & (EXT2FS_CLUSTER_RATIO(fs) - 1);
1809         return new_block;
1810 }
1811
1812 struct process_block_struct {
1813         ext2_resize_t           rfs;
1814         ext2_ino_t              ino;
1815         ext2_ino_t              old_ino;
1816         struct ext2_inode *     inode;
1817         errcode_t               error;
1818         int                     is_dir;
1819         int                     changed;
1820         int                     has_extents;
1821 };
1822
1823 static int process_block(ext2_filsys fs, blk64_t        *block_nr,
1824                          e2_blkcnt_t blockcnt,
1825                          blk64_t ref_block EXT2FS_ATTR((unused)),
1826                          int ref_offset EXT2FS_ATTR((unused)), void *priv_data)
1827 {
1828         struct process_block_struct *pb;
1829         errcode_t       retval;
1830         blk64_t         block, new_block;
1831         int             ret = 0;
1832
1833         pb = (struct process_block_struct *) priv_data;
1834         block = *block_nr;
1835         if (pb->rfs->bmap) {
1836                 new_block = extent_translate(fs, pb->rfs->bmap, block);
1837                 if (new_block) {
1838                         *block_nr = new_block;
1839                         ret |= BLOCK_CHANGED;
1840                         pb->changed = 1;
1841 #ifdef RESIZE2FS_DEBUG
1842                         if (pb->rfs->flags & RESIZE_DEBUG_BMOVE)
1843                                 printf("ino=%u, blockcnt=%lld, %llu->%llu\n",
1844                                        pb->old_ino, blockcnt, block,
1845                                        new_block);
1846 #endif
1847                         block = new_block;
1848                 }
1849         }
1850
1851         if (pb->is_dir) {
1852                 retval = ext2fs_add_dir_block2(fs->dblist, pb->ino,
1853                                                block, (int) blockcnt);
1854                 if (retval) {
1855                         pb->error = retval;
1856                         ret |= BLOCK_ABORT;
1857                 }
1858         }
1859         return ret;
1860 }
1861
1862 /*
1863  * Progress callback
1864  */
1865 static errcode_t progress_callback(ext2_filsys fs,
1866                                    ext2_inode_scan scan EXT2FS_ATTR((unused)),
1867                                    dgrp_t group, void * priv_data)
1868 {
1869         ext2_resize_t rfs = (ext2_resize_t) priv_data;
1870         errcode_t               retval;
1871
1872         /*
1873          * This check is to protect against old ext2 libraries.  It
1874          * shouldn't be needed against new libraries.
1875          */
1876         if ((group+1) == 0)
1877                 return 0;
1878
1879         if (rfs->progress) {
1880                 io_channel_flush(fs->io);
1881                 retval = (rfs->progress)(rfs, E2_RSZ_INODE_SCAN_PASS,
1882                                          group+1, fs->group_desc_count);
1883                 if (retval)
1884                         return retval;
1885         }
1886
1887         return 0;
1888 }
1889
1890 static errcode_t migrate_ea_block(ext2_resize_t rfs, ext2_ino_t ino,
1891                                   struct ext2_inode *inode, int *changed)
1892 {
1893         char *buf = NULL;
1894         blk64_t new_block;
1895         errcode_t err = 0;
1896
1897         /* No EA block or no remapping?  Quit early. */
1898         if (ext2fs_file_acl_block(rfs->old_fs, inode) == 0 || !rfs->bmap)
1899                 return 0;
1900         new_block = extent_translate(rfs->old_fs, rfs->bmap,
1901                 ext2fs_file_acl_block(rfs->old_fs, inode));
1902         if (new_block == 0)
1903                 return 0;
1904
1905         /* Set the new ACL block */
1906         ext2fs_file_acl_block_set(rfs->old_fs, inode, new_block);
1907
1908         /* Update checksum */
1909         if (ext2fs_has_feature_metadata_csum(rfs->new_fs->super)) {
1910                 err = ext2fs_get_mem(rfs->old_fs->blocksize, &buf);
1911                 if (err)
1912                         return err;
1913                 rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
1914                 err = ext2fs_read_ext_attr3(rfs->old_fs, new_block, buf, ino);
1915                 rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
1916                 if (err)
1917                         goto out;
1918                 err = ext2fs_write_ext_attr3(rfs->old_fs, new_block, buf, ino);
1919                 if (err)
1920                         goto out;
1921         }
1922         *changed = 1;
1923
1924 out:
1925         ext2fs_free_mem(&buf);
1926         return err;
1927 }
1928
1929 /* Rewrite extents */
1930 static errcode_t rewrite_extents(ext2_filsys fs, ext2_ino_t ino)
1931 {
1932         ext2_extent_handle_t    handle;
1933         struct ext2fs_extent    extent;
1934         errcode_t               errcode;
1935         struct ext2_extent_info info;
1936
1937         errcode = ext2fs_extent_open(fs, ino, &handle);
1938         if (errcode)
1939                 return errcode;
1940
1941         errcode = ext2fs_extent_get(handle, EXT2_EXTENT_ROOT, &extent);
1942         if (errcode)
1943                 goto out;
1944
1945         do {
1946                 errcode = ext2fs_extent_get_info(handle, &info);
1947                 if (errcode)
1948                         break;
1949
1950                 /*
1951                  * If this is the first extent in an extent block that we
1952                  * haven't visited, rewrite the extent to force the ETB
1953                  * checksum to be rewritten.
1954                  */
1955                 if (info.curr_entry == 1 && info.curr_level != 0 &&
1956                     !(extent.e_flags & EXT2_EXTENT_FLAGS_SECOND_VISIT)) {
1957                         errcode = ext2fs_extent_replace(handle, 0, &extent);
1958                         if (errcode)
1959                                 break;
1960                 }
1961
1962                 /* Skip to the end of a block of leaf nodes */
1963                 if (extent.e_flags & EXT2_EXTENT_FLAGS_LEAF) {
1964                         errcode = ext2fs_extent_get(handle,
1965                                                     EXT2_EXTENT_LAST_SIB,
1966                                                     &extent);
1967                         if (errcode)
1968                                 break;
1969                 }
1970
1971                 errcode = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT, &extent);
1972         } while (errcode == 0);
1973
1974 out:
1975         /* Ok if we run off the end */
1976         if (errcode == EXT2_ET_EXTENT_NO_NEXT)
1977                 errcode = 0;
1978         ext2fs_extent_free(handle);
1979         return errcode;
1980 }
1981
1982 static void quiet_com_err_proc(const char *whoami EXT2FS_ATTR((unused)),
1983                                errcode_t code EXT2FS_ATTR((unused)),
1984                                const char *fmt EXT2FS_ATTR((unused)),
1985                                va_list args EXT2FS_ATTR((unused)))
1986 {
1987 }
1988
1989 static errcode_t inode_scan_and_fix(ext2_resize_t rfs)
1990 {
1991         struct process_block_struct     pb;
1992         ext2_ino_t              ino, new_inode;
1993         struct ext2_inode       *inode = NULL;
1994         ext2_inode_scan         scan = NULL;
1995         errcode_t               retval;
1996         char                    *block_buf = 0;
1997         ext2_ino_t              start_to_move;
1998         int                     inode_size;
1999
2000         if ((rfs->old_fs->group_desc_count <=
2001              rfs->new_fs->group_desc_count) &&
2002             !rfs->bmap)
2003                 return 0;
2004
2005         set_com_err_hook(quiet_com_err_proc);
2006
2007         retval = ext2fs_open_inode_scan(rfs->old_fs, 0, &scan);
2008         if (retval) goto errout;
2009
2010         retval = ext2fs_init_dblist(rfs->old_fs, 0);
2011         if (retval) goto errout;
2012         retval = ext2fs_get_array(rfs->old_fs->blocksize, 3, &block_buf);
2013         if (retval) goto errout;
2014
2015         start_to_move = (rfs->new_fs->group_desc_count *
2016                          rfs->new_fs->super->s_inodes_per_group);
2017
2018         if (rfs->progress) {
2019                 retval = (rfs->progress)(rfs, E2_RSZ_INODE_SCAN_PASS,
2020                                          0, rfs->old_fs->group_desc_count);
2021                 if (retval)
2022                         goto errout;
2023         }
2024         ext2fs_set_inode_callback(scan, progress_callback, (void *) rfs);
2025         pb.rfs = rfs;
2026         pb.inode = inode;
2027         pb.error = 0;
2028         new_inode = EXT2_FIRST_INODE(rfs->new_fs->super);
2029         inode_size = EXT2_INODE_SIZE(rfs->new_fs->super);
2030         inode = malloc(inode_size);
2031         if (!inode) {
2032                 retval = ENOMEM;
2033                 goto errout;
2034         }
2035         /*
2036          * First, copy all of the inodes that need to be moved
2037          * elsewhere in the inode table
2038          */
2039         while (1) {
2040                 retval = ext2fs_get_next_inode_full(scan, &ino, inode, inode_size);
2041                 if (retval) goto errout;
2042                 if (!ino)
2043                         break;
2044
2045                 if (inode->i_links_count == 0 && ino != EXT2_RESIZE_INO)
2046                         continue; /* inode not in use */
2047
2048                 pb.is_dir = LINUX_S_ISDIR(inode->i_mode);
2049                 pb.changed = 0;
2050
2051                 /* Remap EA block */
2052                 retval = migrate_ea_block(rfs, ino, inode, &pb.changed);
2053                 if (retval)
2054                         goto errout;
2055
2056                 new_inode = ino;
2057                 if (ino <= start_to_move)
2058                         goto remap_blocks; /* Don't need to move inode. */
2059
2060                 /*
2061                  * Moving an extended attribute inode requires updating all inodes
2062                  * that reference it which is a lot more involved.
2063                  */
2064                 if (inode->i_flags & EXT4_EA_INODE_FL) {
2065                         retval = EXT2_ET_CANNOT_MOVE_EA_INODE;
2066                         goto errout;
2067                 }
2068
2069                 /*
2070                  * Find a new inode.  Now that extents and directory blocks
2071                  * are tied to the inode number through the checksum, we must
2072                  * set up the new inode before we start rewriting blocks.
2073                  */
2074                 retval = ext2fs_new_inode(rfs->new_fs, 0, 0, 0, &new_inode);
2075                 if (retval)
2076                         goto errout;
2077
2078                 ext2fs_inode_alloc_stats2(rfs->new_fs, new_inode, +1,
2079                                           pb.is_dir);
2080                 inode->i_ctime = time(0);
2081                 retval = ext2fs_write_inode_full(rfs->old_fs, new_inode,
2082                                                 inode, inode_size);
2083                 if (retval)
2084                         goto errout;
2085                 pb.changed = 0;
2086
2087 #ifdef RESIZE2FS_DEBUG
2088                 if (rfs->flags & RESIZE_DEBUG_INODEMAP)
2089                         printf("Inode moved %u->%u\n", ino, new_inode);
2090 #endif
2091                 if (!rfs->imap) {
2092                         retval = ext2fs_create_extent_table(&rfs->imap, 0);
2093                         if (retval)
2094                                 goto errout;
2095                 }
2096                 ext2fs_add_extent_entry(rfs->imap, ino, new_inode);
2097
2098 remap_blocks:
2099                 if (pb.changed)
2100                         retval = ext2fs_write_inode_full(rfs->old_fs,
2101                                                          new_inode,
2102                                                          inode, inode_size);
2103                 if (retval)
2104                         goto errout;
2105
2106                 /* Rewrite extent block checksums with new inode number */
2107                 if (ext2fs_has_feature_metadata_csum(rfs->old_fs->super) &&
2108                     (inode->i_flags & EXT4_EXTENTS_FL)) {
2109                         rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
2110                         retval = rewrite_extents(rfs->old_fs, new_inode);
2111                         rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
2112                         if (retval)
2113                                 goto errout;
2114                 }
2115
2116                 /*
2117                  * Update inodes to point to new blocks; schedule directory
2118                  * blocks for inode remapping.  Need to write out dir blocks
2119                  * with new inode numbers if we have metadata_csum enabled.
2120                  */
2121                 if (ext2fs_inode_has_valid_blocks2(rfs->old_fs, inode) &&
2122                     (rfs->bmap || pb.is_dir)) {
2123                         pb.ino = new_inode;
2124                         pb.old_ino = ino;
2125                         pb.has_extents = inode->i_flags & EXT4_EXTENTS_FL;
2126                         rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
2127                         retval = ext2fs_block_iterate3(rfs->old_fs,
2128                                                        new_inode, 0, block_buf,
2129                                                        process_block, &pb);
2130                         rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
2131                         if (retval)
2132                                 goto errout;
2133                         if (pb.error) {
2134                                 retval = pb.error;
2135                                 goto errout;
2136                         }
2137                 } else if ((inode->i_flags & EXT4_INLINE_DATA_FL) &&
2138                            (rfs->bmap || pb.is_dir)) {
2139                         /* inline data dir; update it too */
2140                         retval = ext2fs_add_dir_block2(rfs->old_fs->dblist,
2141                                                        new_inode, 0, 0);
2142                         if (retval)
2143                                 goto errout;
2144                 }
2145         }
2146         io_channel_flush(rfs->old_fs->io);
2147
2148 errout:
2149         reset_com_err_hook();
2150         if (rfs->bmap) {
2151                 ext2fs_free_extent_table(rfs->bmap);
2152                 rfs->bmap = 0;
2153         }
2154         if (scan)
2155                 ext2fs_close_inode_scan(scan);
2156         if (block_buf)
2157                 ext2fs_free_mem(&block_buf);
2158         free(inode);
2159         return retval;
2160 }
2161
2162 /* --------------------------------------------------------------------
2163  *
2164  * Resize processing, phase 4.
2165  *
2166  * --------------------------------------------------------------------
2167  */
2168
2169 struct istruct {
2170         ext2_resize_t rfs;
2171         errcode_t       err;
2172         unsigned int    max_dirs;
2173         unsigned int    num;
2174 };
2175
2176 static int check_and_change_inodes(ext2_ino_t dir,
2177                                    int entry EXT2FS_ATTR((unused)),
2178                                    struct ext2_dir_entry *dirent, int offset,
2179                                    int  blocksize EXT2FS_ATTR((unused)),
2180                                    char *buf EXT2FS_ATTR((unused)),
2181                                    void *priv_data)
2182 {
2183         struct istruct *is = (struct istruct *) priv_data;
2184         struct ext2_inode       inode;
2185         ext2_ino_t              new_inode;
2186         errcode_t               retval;
2187         int                     ret = 0;
2188
2189         if (is->rfs->progress && offset == 0) {
2190                 io_channel_flush(is->rfs->old_fs->io);
2191                 is->err = (is->rfs->progress)(is->rfs,
2192                                               E2_RSZ_INODE_REF_UPD_PASS,
2193                                               ++is->num, is->max_dirs);
2194                 if (is->err)
2195                         return DIRENT_ABORT;
2196         }
2197
2198         /*
2199          * If we have checksums enabled and the inode wasn't present in the
2200          * old fs, then we must rewrite all dir blocks with new checksums.
2201          */
2202         if (ext2fs_has_feature_metadata_csum(is->rfs->old_fs->super) &&
2203             !ext2fs_test_inode_bitmap2(is->rfs->old_fs->inode_map, dir))
2204                 ret |= DIRENT_CHANGED;
2205
2206         if (!dirent->inode)
2207                 return ret;
2208
2209         new_inode = ext2fs_extent_translate(is->rfs->imap, dirent->inode);
2210
2211         if (!new_inode)
2212                 return ret;
2213 #ifdef RESIZE2FS_DEBUG
2214         if (is->rfs->flags & RESIZE_DEBUG_INODEMAP)
2215                 printf("Inode translate (dir=%u, name=%.*s, %u->%u)\n",
2216                        dir, ext2fs_dirent_name_len(dirent), dirent->name,
2217                        dirent->inode, new_inode);
2218 #endif
2219
2220         dirent->inode = new_inode;
2221
2222         /* Update the directory mtime and ctime */
2223         retval = ext2fs_read_inode(is->rfs->old_fs, dir, &inode);
2224         if (retval == 0) {
2225                 inode.i_mtime = inode.i_ctime = time(0);
2226                 is->err = ext2fs_write_inode(is->rfs->old_fs, dir, &inode);
2227                 if (is->err)
2228                         return ret | DIRENT_ABORT;
2229         }
2230
2231         return ret | DIRENT_CHANGED;
2232 }
2233
2234 static errcode_t inode_ref_fix(ext2_resize_t rfs)
2235 {
2236         errcode_t               retval;
2237         struct istruct          is;
2238
2239         if (!rfs->imap)
2240                 return 0;
2241
2242         /*
2243          * Now, we iterate over all of the directories to update the
2244          * inode references
2245          */
2246         is.num = 0;
2247         is.max_dirs = ext2fs_dblist_count2(rfs->old_fs->dblist);
2248         is.rfs = rfs;
2249         is.err = 0;
2250
2251         if (rfs->progress) {
2252                 retval = (rfs->progress)(rfs, E2_RSZ_INODE_REF_UPD_PASS,
2253                                          0, is.max_dirs);
2254                 if (retval)
2255                         goto errout;
2256         }
2257
2258         rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
2259         retval = ext2fs_dblist_dir_iterate(rfs->old_fs->dblist,
2260                                            DIRENT_FLAG_INCLUDE_EMPTY, 0,
2261                                            check_and_change_inodes, &is);
2262         rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
2263         if (retval)
2264                 goto errout;
2265         if (is.err) {
2266                 retval = is.err;
2267                 goto errout;
2268         }
2269
2270         if (rfs->progress && (is.num < is.max_dirs))
2271                 (rfs->progress)(rfs, E2_RSZ_INODE_REF_UPD_PASS,
2272                                 is.max_dirs, is.max_dirs);
2273
2274 errout:
2275         ext2fs_free_extent_table(rfs->imap);
2276         rfs->imap = 0;
2277         return retval;
2278 }
2279
2280
2281 /* --------------------------------------------------------------------
2282  *
2283  * Resize processing, phase 5.
2284  *
2285  * In this phase we actually move the inode table around, and then
2286  * update the summary statistics.  This is scary, since aborting here
2287  * will potentially scramble the filesystem.  (We are moving the
2288  * inode tables around in place, and so the potential for lost data,
2289  * or at the very least scrambling the mapping between filenames and
2290  * inode numbers is very high in case of a power failure here.)
2291  * --------------------------------------------------------------------
2292  */
2293
2294
2295 /*
2296  * A very scary routine --- this one moves the inode table around!!!
2297  *
2298  * After this you have to use the rfs->new_fs file handle to read and
2299  * write inodes.
2300  */
2301 static errcode_t move_itables(ext2_resize_t rfs)
2302 {
2303         int             n, num, size;
2304         long long       diff;
2305         dgrp_t          i, max_groups;
2306         ext2_filsys     fs = rfs->new_fs;
2307         char            *cp;
2308         blk64_t         old_blk, new_blk, blk, cluster_freed;
2309         errcode_t       retval;
2310         int             to_move, moved;
2311         unsigned int    j;
2312         ext2fs_block_bitmap     new_bmap = NULL;
2313
2314         max_groups = fs->group_desc_count;
2315         if (max_groups > rfs->old_fs->group_desc_count)
2316                 max_groups = rfs->old_fs->group_desc_count;
2317
2318         size = fs->blocksize * fs->inode_blocks_per_group;
2319         if (!rfs->itable_buf) {
2320                 retval = ext2fs_get_mem(size, &rfs->itable_buf);
2321                 if (retval)
2322                         return retval;
2323         }
2324
2325         if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
2326                 retval = ext2fs_allocate_block_bitmap(fs, _("new meta blocks"),
2327                                                       &new_bmap);
2328                 if (retval)
2329                         return retval;
2330
2331                 retval = mark_table_blocks(fs, new_bmap);
2332                 if (retval)
2333                         goto errout;
2334         }
2335
2336         /*
2337          * Figure out how many inode tables we need to move
2338          */
2339         to_move = moved = 0;
2340         for (i=0; i < max_groups; i++)
2341                 if (ext2fs_inode_table_loc(rfs->old_fs, i) !=
2342                     ext2fs_inode_table_loc(fs, i))
2343                         to_move++;
2344
2345         if (to_move == 0) {
2346                 retval = 0;
2347                 goto errout;
2348         }
2349
2350         if (rfs->progress) {
2351                 retval = rfs->progress(rfs, E2_RSZ_MOVE_ITABLE_PASS,
2352                                        0, to_move);
2353                 if (retval)
2354                         goto errout;
2355         }
2356
2357         rfs->old_fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
2358
2359         for (i=0; i < max_groups; i++) {
2360                 old_blk = ext2fs_inode_table_loc(rfs->old_fs, i);
2361                 new_blk = ext2fs_inode_table_loc(fs, i);
2362                 diff = new_blk - old_blk;
2363
2364 #ifdef RESIZE2FS_DEBUG
2365                 if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
2366                         printf("Itable move group %d block %llu->%llu (diff %lld)\n",
2367                                i, old_blk, new_blk, diff);
2368 #endif
2369
2370                 if (!diff)
2371                         continue;
2372                 if (diff < 0)
2373                         diff = 0;
2374
2375                 retval = io_channel_read_blk64(fs->io, old_blk,
2376                                                fs->inode_blocks_per_group,
2377                                                rfs->itable_buf);
2378                 if (retval)
2379                         goto errout;
2380                 /*
2381                  * The end of the inode table segment often contains
2382                  * all zeros, and we're often only moving the inode
2383                  * table down a block or two.  If so, we can optimize
2384                  * things by not rewriting blocks that we know to be zero
2385                  * already.
2386                  */
2387                 for (cp = rfs->itable_buf+size-1, n=0; n < size; n++, cp--)
2388                         if (*cp)
2389                                 break;
2390                 n = n >> EXT2_BLOCK_SIZE_BITS(fs->super);
2391 #ifdef RESIZE2FS_DEBUG
2392                 if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
2393                         printf("%d blocks of zeros...\n", n);
2394 #endif
2395                 num = fs->inode_blocks_per_group;
2396                 if (n > diff)
2397                         num -= n;
2398
2399                 retval = io_channel_write_blk64(fs->io, new_blk,
2400                                                 num, rfs->itable_buf);
2401                 if (retval) {
2402                         io_channel_write_blk64(fs->io, old_blk,
2403                                                num, rfs->itable_buf);
2404                         goto errout;
2405                 }
2406                 if (n > diff) {
2407                         retval = io_channel_write_blk64(fs->io,
2408                               old_blk + fs->inode_blocks_per_group,
2409                               diff, (rfs->itable_buf +
2410                                      (fs->inode_blocks_per_group - diff) *
2411                                      fs->blocksize));
2412                         if (retval)
2413                                 goto errout;
2414                 }
2415
2416                 for (blk = ext2fs_inode_table_loc(rfs->old_fs, i), j=0;
2417                      j < fs->inode_blocks_per_group;) {
2418                         if (new_bmap == NULL ||
2419                             !ext2fs_test_block_bitmap2(new_bmap, blk)) {
2420                                 ext2fs_block_alloc_stats2(fs, blk, -1);
2421                                 cluster_freed = EXT2FS_CLUSTER_RATIO(fs) -
2422                                                 (blk & EXT2FS_CLUSTER_MASK(fs));
2423                                 blk += cluster_freed;
2424                                 j += cluster_freed;
2425                                 continue;
2426                         }
2427                         blk++;
2428                         j++;
2429                 }
2430
2431                 ext2fs_inode_table_loc_set(rfs->old_fs, i, new_blk);
2432                 ext2fs_group_desc_csum_set(rfs->old_fs, i);
2433                 ext2fs_mark_super_dirty(rfs->old_fs);
2434                 ext2fs_flush(rfs->old_fs);
2435
2436                 if (rfs->progress) {
2437                         retval = rfs->progress(rfs, E2_RSZ_MOVE_ITABLE_PASS,
2438                                                ++moved, to_move);
2439                         if (retval)
2440                                 goto errout;
2441                 }
2442         }
2443         mark_table_blocks(fs, fs->block_map);
2444         ext2fs_flush(fs);
2445 #ifdef RESIZE2FS_DEBUG
2446         if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
2447                 printf("Inode table move finished.\n");
2448 #endif
2449         retval = 0;
2450
2451 errout:
2452         if (new_bmap)
2453                 ext2fs_free_block_bitmap(new_bmap);
2454         return retval;
2455 }
2456
2457 /*
2458  * This function is used when expanding a file system.  It frees the
2459  * superblock and block group descriptor blocks from the block group
2460  * which is no longer the last block group.
2461  */
2462 static errcode_t clear_sparse_super2_last_group(ext2_resize_t rfs)
2463 {
2464         ext2_filsys     fs = rfs->new_fs;
2465         ext2_filsys     old_fs = rfs->old_fs;
2466         errcode_t       retval;
2467         dgrp_t          old_last_bg = rfs->old_fs->group_desc_count - 1;
2468         dgrp_t          last_bg = fs->group_desc_count - 1;
2469         blk64_t         sb, old_desc;
2470         blk_t           num;
2471
2472         if (!ext2fs_has_feature_sparse_super2(fs->super))
2473                 return 0;
2474
2475         if (last_bg <= old_last_bg)
2476                 return 0;
2477
2478         if (fs->super->s_backup_bgs[0] == old_fs->super->s_backup_bgs[0] &&
2479             fs->super->s_backup_bgs[1] == old_fs->super->s_backup_bgs[1])
2480                 return 0;
2481
2482         if (old_fs->super->s_backup_bgs[0] != old_last_bg &&
2483             old_fs->super->s_backup_bgs[1] != old_last_bg)
2484                 return 0;
2485
2486         if (fs->super->s_backup_bgs[0] == old_last_bg ||
2487             fs->super->s_backup_bgs[1] == old_last_bg)
2488                 return 0;
2489
2490         if (old_last_bg == 0)
2491                 return 0;
2492
2493         retval = ext2fs_super_and_bgd_loc2(rfs->old_fs, old_last_bg,
2494                                            &sb, &old_desc, NULL, &num);
2495         if (retval)
2496                 return retval;
2497
2498         if (sb)
2499                 ext2fs_unmark_block_bitmap2(fs->block_map, sb);
2500         if (old_desc)
2501                 ext2fs_unmark_block_bitmap_range2(fs->block_map, old_desc, num);
2502         return 0;
2503 }
2504
2505 /*
2506  * This function is used when shrinking a file system.  We need to
2507  * utilize blocks from what will be the new last block group for the
2508  * backup superblock and block group descriptor blocks.
2509  * Unfortunately, those blocks may be used by other files or fs
2510  * metadata blocks.  We need to mark them as being in use.
2511  */
2512 static errcode_t reserve_sparse_super2_last_group(ext2_resize_t rfs,
2513                                                  ext2fs_block_bitmap meta_bmap)
2514 {
2515         ext2_filsys     fs = rfs->new_fs;
2516         ext2_filsys     old_fs = rfs->old_fs;
2517         errcode_t       retval;
2518         dgrp_t          old_last_bg = rfs->old_fs->group_desc_count - 1;
2519         dgrp_t          last_bg = fs->group_desc_count - 1;
2520         dgrp_t          g;
2521         blk64_t         blk, sb, old_desc;
2522         blk_t           i, num;
2523         int             realloc = 0;
2524
2525         if (!ext2fs_has_feature_sparse_super2(fs->super))
2526                 return 0;
2527
2528         if (last_bg >= old_last_bg)
2529                 return 0;
2530
2531         if (fs->super->s_backup_bgs[0] == old_fs->super->s_backup_bgs[0] &&
2532             fs->super->s_backup_bgs[1] == old_fs->super->s_backup_bgs[1])
2533                 return 0;
2534
2535         if (fs->super->s_backup_bgs[0] != last_bg &&
2536             fs->super->s_backup_bgs[1] != last_bg)
2537                 return 0;
2538
2539         if (old_fs->super->s_backup_bgs[0] == last_bg ||
2540             old_fs->super->s_backup_bgs[1] == last_bg)
2541                 return 0;
2542
2543         retval = ext2fs_super_and_bgd_loc2(rfs->new_fs, last_bg,
2544                                            &sb, &old_desc, NULL, &num);
2545         if (retval)
2546                 return retval;
2547
2548         if (last_bg && !sb) {
2549                 fputs(_("Should never happen!  No sb in last super_sparse bg?\n"),
2550                       stderr);
2551                 exit(1);
2552         }
2553         if (old_desc && old_desc != sb+1) {
2554                 fputs(_("Should never happen!  Unexpected old_desc in "
2555                         "super_sparse bg?\n"),
2556                       stderr);
2557                 exit(1);
2558         }
2559         num = (old_desc) ? num : 1;
2560
2561         /* Reserve the backup blocks */
2562         ext2fs_mark_block_bitmap_range2(fs->block_map, sb, num);
2563
2564         for (g = 0; g < fs->group_desc_count; g++) {
2565                 blk64_t mb;
2566
2567                 mb = ext2fs_block_bitmap_loc(fs, g);
2568                 if ((mb >= sb) && (mb < sb + num)) {
2569                         ext2fs_block_bitmap_loc_set(fs, g, 0);
2570                         realloc = 1;
2571                 }
2572                 mb = ext2fs_inode_bitmap_loc(fs, g);
2573                 if ((mb >= sb) && (mb < sb + num)) {
2574                         ext2fs_inode_bitmap_loc_set(fs, g, 0);
2575                         realloc = 1;
2576                 }
2577                 mb = ext2fs_inode_table_loc(fs, g);
2578                 if ((mb < sb + num) &&
2579                     (sb < mb + fs->inode_blocks_per_group)) {
2580                         ext2fs_inode_table_loc_set(fs, g, 0);
2581                         realloc = 1;
2582                 }
2583                 if (realloc) {
2584                         retval = ext2fs_allocate_group_table(fs, g, 0);
2585                         if (retval)
2586                                 return retval;
2587                 }
2588         }
2589
2590         for (blk = sb, i = 0; i < num; blk++, i++) {
2591                 if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
2592                     !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
2593                         ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
2594                         rfs->needed_blocks++;
2595                 }
2596                 ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
2597         }
2598         return 0;
2599 }
2600
2601 /*
2602  * Fix the resize inode
2603  */
2604 static errcode_t fix_resize_inode(ext2_filsys fs)
2605 {
2606         struct ext2_inode       inode;
2607         errcode_t               retval;
2608
2609         if (!ext2fs_has_feature_resize_inode(fs->super))
2610                 return 0;
2611
2612         retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
2613         if (retval) goto errout;
2614
2615         ext2fs_iblk_set(fs, &inode, 1);
2616
2617         retval = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
2618         if (retval) goto errout;
2619
2620         if (!inode.i_block[EXT2_DIND_BLOCK]) {
2621                 /*
2622                  * Avoid zeroing out block #0; that's rude.  This
2623                  * should never happen anyway since the filesystem
2624                  * should be fsck'ed and we assume it is consistent.
2625                  */
2626                 fprintf(stderr, "%s",
2627                         _("Should never happen: resize inode corrupt!\n"));
2628                 exit(1);
2629         }
2630
2631         retval = ext2fs_zero_blocks2(fs, inode.i_block[EXT2_DIND_BLOCK], 1,
2632                                      NULL, NULL);
2633         if (retval)
2634                 goto errout;
2635
2636         retval = ext2fs_create_resize_inode(fs);
2637         if (retval)
2638                 goto errout;
2639
2640 errout:
2641         return retval;
2642 }
2643
2644 /*
2645  * Finally, recalculate the summary information
2646  */
2647 static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
2648 {
2649         blk64_t         blk;
2650         ext2_ino_t      ino;
2651         unsigned int    group = 0;
2652         unsigned int    count = 0;
2653         blk64_t         total_blocks_free = 0;
2654         int             total_inodes_free = 0;
2655         int             group_free = 0;
2656         int             uninit = 0;
2657         blk64_t         super_blk, old_desc_blk, new_desc_blk;
2658         int             old_desc_blocks;
2659
2660         /*
2661          * First calculate the block statistics
2662          */
2663         uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT);
2664         ext2fs_super_and_bgd_loc2(fs, group, &super_blk, &old_desc_blk,
2665                                   &new_desc_blk, 0);
2666         if (ext2fs_has_feature_meta_bg(fs->super))
2667                 old_desc_blocks = fs->super->s_first_meta_bg;
2668         else
2669                 old_desc_blocks = fs->desc_blocks +
2670                         fs->super->s_reserved_gdt_blocks;
2671         for (blk = B2C(fs->super->s_first_data_block);
2672              blk < ext2fs_blocks_count(fs->super);
2673              blk += EXT2FS_CLUSTER_RATIO(fs)) {
2674                 if ((uninit &&
2675                      !(EQ_CLSTR(blk, super_blk) ||
2676                        ((old_desc_blk && old_desc_blocks &&
2677                          GE_CLSTR(blk, old_desc_blk) &&
2678                          LT_CLSTR(blk, old_desc_blk + old_desc_blocks))) ||
2679                        ((new_desc_blk && EQ_CLSTR(blk, new_desc_blk))) ||
2680                        EQ_CLSTR(blk, ext2fs_block_bitmap_loc(fs, group)) ||
2681                        EQ_CLSTR(blk, ext2fs_inode_bitmap_loc(fs, group)) ||
2682                        ((GE_CLSTR(blk, ext2fs_inode_table_loc(fs, group)) &&
2683                          LT_CLSTR(blk, ext2fs_inode_table_loc(fs, group)
2684                                   + fs->inode_blocks_per_group))))) ||
2685                     (!ext2fs_fast_test_block_bitmap2(fs->block_map, blk))) {
2686                         group_free++;
2687                         total_blocks_free++;
2688                 }
2689                 count++;
2690                 if ((count == fs->super->s_clusters_per_group) ||
2691                     EQ_CLSTR(blk, ext2fs_blocks_count(fs->super)-1)) {
2692                         ext2fs_bg_free_blocks_count_set(fs, group, group_free);
2693                         ext2fs_group_desc_csum_set(fs, group);
2694                         group++;
2695                         if (group >= fs->group_desc_count)
2696                                 break;
2697                         count = 0;
2698                         group_free = 0;
2699                         uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT);
2700                         ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
2701                                                   &old_desc_blk,
2702                                                   &new_desc_blk, 0);
2703                         if (ext2fs_has_feature_meta_bg(fs->super))
2704                                 old_desc_blocks = fs->super->s_first_meta_bg;
2705                         else
2706                                 old_desc_blocks = fs->desc_blocks +
2707                                         fs->super->s_reserved_gdt_blocks;
2708                 }
2709         }
2710         total_blocks_free = C2B(total_blocks_free);
2711         ext2fs_free_blocks_count_set(fs->super, total_blocks_free);
2712
2713         /*
2714          * Next, calculate the inode statistics
2715          */
2716         group_free = 0;
2717         count = 0;
2718         group = 0;
2719
2720         /* Protect loop from wrap-around if s_inodes_count maxed */
2721         uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT);
2722         for (ino = 1; ino <= fs->super->s_inodes_count && ino > 0; ino++) {
2723                 if (uninit ||
2724                     !ext2fs_fast_test_inode_bitmap2(fs->inode_map, ino)) {
2725                         group_free++;
2726                         total_inodes_free++;
2727                 }
2728                 count++;
2729                 if ((count == fs->super->s_inodes_per_group) ||
2730                     (ino == fs->super->s_inodes_count)) {
2731                         ext2fs_bg_free_inodes_count_set(fs, group, group_free);
2732                         ext2fs_group_desc_csum_set(fs, group);
2733                         group++;
2734                         if (group >= fs->group_desc_count)
2735                                 break;
2736                         count = 0;
2737                         group_free = 0;
2738                         uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT);
2739                 }
2740         }
2741         fs->super->s_free_inodes_count = total_inodes_free;
2742         ext2fs_mark_super_dirty(fs);
2743         return 0;
2744 }
2745
2746 /*
2747  *  Journal may have been relocated; update the backup journal blocks
2748  *  in the superblock.
2749  */
2750 static errcode_t fix_sb_journal_backup(ext2_filsys fs)
2751 {
2752         errcode_t         retval;
2753         struct ext2_inode inode;
2754
2755         if (!ext2fs_has_feature_journal(fs->super))
2756                 return 0;
2757
2758         /* External journal? Nothing to do. */
2759         if (fs->super->s_journal_dev && !fs->super->s_journal_inum)
2760                 return 0;
2761
2762         retval = ext2fs_read_inode(fs, fs->super->s_journal_inum, &inode);
2763         if (retval)
2764                 return retval;
2765         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
2766         fs->super->s_jnl_blocks[15] = inode.i_size_high;
2767         fs->super->s_jnl_blocks[16] = inode.i_size;
2768         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
2769         ext2fs_mark_super_dirty(fs);
2770         return 0;
2771 }
2772
2773 static int calc_group_overhead(ext2_filsys fs, blk64_t grp,
2774                                int old_desc_blocks)
2775 {
2776         blk64_t super_blk, old_desc_blk, new_desc_blk;
2777         int overhead;
2778
2779         /* inode table blocks plus allocation bitmaps */
2780         overhead = fs->inode_blocks_per_group + 2;
2781
2782         ext2fs_super_and_bgd_loc2(fs, grp, &super_blk,
2783                                   &old_desc_blk, &new_desc_blk, 0);
2784         if ((grp == 0) || super_blk)
2785                 overhead++;
2786         if (old_desc_blk)
2787                 overhead += old_desc_blocks;
2788         else if (new_desc_blk)
2789                 overhead++;
2790         return overhead;
2791 }
2792
2793
2794 /*
2795  * calcluate the minimum number of blocks the given fs can be resized to
2796  */
2797 blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
2798 {
2799         ext2_ino_t inode_count;
2800         dgrp_t groups, flex_groups;
2801         blk64_t blks_needed, data_blocks;
2802         blk64_t grp, data_needed, last_start;
2803         blk64_t overhead = 0;
2804         int old_desc_blocks;
2805         int flexbg_size = 1 << fs->super->s_log_groups_per_flex;
2806
2807         /*
2808          * first figure out how many group descriptors we need to
2809          * handle the number of inodes we have
2810          */
2811         inode_count = fs->super->s_inodes_count -
2812                 fs->super->s_free_inodes_count;
2813         blks_needed = ext2fs_div_ceil(inode_count,
2814                                       fs->super->s_inodes_per_group) *
2815                 (blk64_t) EXT2_BLOCKS_PER_GROUP(fs->super);
2816         groups = ext2fs_div64_ceil(blks_needed,
2817                                    EXT2_BLOCKS_PER_GROUP(fs->super));
2818 #ifdef RESIZE2FS_DEBUG
2819         if (flags & RESIZE_DEBUG_MIN_CALC)
2820                 printf("fs has %d inodes, %d groups required.\n",
2821                        inode_count, groups);
2822 #endif
2823
2824         /*
2825          * number of old-style block group descriptor blocks
2826          */
2827         if (ext2fs_has_feature_meta_bg(fs->super))
2828                 old_desc_blocks = fs->super->s_first_meta_bg;
2829         else
2830                 old_desc_blocks = fs->desc_blocks +
2831                         fs->super->s_reserved_gdt_blocks;
2832
2833         /* calculate how many blocks are needed for data */
2834         data_needed = ext2fs_blocks_count(fs->super) -
2835                 ext2fs_free_blocks_count(fs->super);
2836
2837         for (grp = 0; grp < fs->group_desc_count; grp++)
2838                 data_needed -= calc_group_overhead(fs, grp, old_desc_blocks);
2839 #ifdef RESIZE2FS_DEBUG
2840         if (flags & RESIZE_DEBUG_MIN_CALC)
2841                 printf("fs requires %llu data blocks.\n", data_needed);
2842 #endif
2843
2844         /*
2845          * For ext4 we need to allow for up to a flex_bg worth of
2846          * inode tables of slack space so the resize operation can be
2847          * guaranteed to finish.
2848          */
2849         flex_groups = groups;
2850         if (ext2fs_has_feature_flex_bg(fs->super)) {
2851                 dgrp_t remainder = groups & (flexbg_size - 1);
2852
2853                 flex_groups += flexbg_size - remainder;
2854                 if (flex_groups > fs->group_desc_count)
2855                         flex_groups = fs->group_desc_count;
2856         }
2857
2858         /*
2859          * figure out how many data blocks we have given the number of groups
2860          * we need for our inodes
2861          */
2862         data_blocks = EXT2_GROUPS_TO_BLOCKS(fs->super, groups);
2863         last_start = 0;
2864         for (grp = 0; grp < flex_groups; grp++) {
2865                 overhead = calc_group_overhead(fs, grp, old_desc_blocks);
2866
2867                 /*
2868                  * we want to keep track of how much data we can store in
2869                  * the groups leading up to the last group so we can determine
2870                  * how big the last group needs to be
2871                  */
2872                 if (grp < (groups - 1))
2873                         last_start += EXT2_BLOCKS_PER_GROUP(fs->super) -
2874                                 overhead;
2875
2876                 if (data_blocks > overhead)
2877                         data_blocks -= overhead;
2878                 else
2879                         data_blocks = 0;
2880         }
2881 #ifdef RESIZE2FS_DEBUG
2882         if (flags & RESIZE_DEBUG_MIN_CALC)
2883                 printf("With %d group(s), we have %llu blocks available.\n",
2884                        groups, data_blocks);
2885 #endif
2886
2887         /*
2888          * if we need more group descriptors in order to accomodate our data
2889          * then we need to add them here
2890          */
2891         blks_needed = data_needed;
2892         while (blks_needed > data_blocks) {
2893                 blk64_t remainder = blks_needed - data_blocks;
2894                 dgrp_t extra_grps;
2895
2896                 /* figure out how many more groups we need for the data */
2897                 extra_grps = ext2fs_div64_ceil(remainder,
2898                                                EXT2_BLOCKS_PER_GROUP(fs->super));
2899
2900                 data_blocks += EXT2_GROUPS_TO_BLOCKS(fs->super, extra_grps);
2901
2902                 /* ok we have to account for the last group */
2903                 overhead = calc_group_overhead(fs, groups-1, old_desc_blocks);
2904                 last_start += EXT2_BLOCKS_PER_GROUP(fs->super) - overhead;
2905
2906                 grp = flex_groups;
2907                 groups += extra_grps;
2908                 if (!ext2fs_has_feature_flex_bg(fs->super))
2909                         flex_groups = groups;
2910                 else if (groups > flex_groups) {
2911                         dgrp_t r = groups & (flexbg_size - 1);
2912
2913                         flex_groups = groups + flexbg_size - r;
2914                         if (flex_groups > fs->group_desc_count)
2915                                 flex_groups = fs->group_desc_count;
2916                 }
2917
2918                 for (; grp < flex_groups; grp++) {
2919                         overhead = calc_group_overhead(fs, grp,
2920                                                        old_desc_blocks);
2921
2922                         /*
2923                          * again, we need to see how much data we cram into
2924                          * all of the groups leading up to the last group
2925                          */
2926                         if (grp < groups - 1)
2927                                 last_start += EXT2_BLOCKS_PER_GROUP(fs->super)
2928                                         - overhead;
2929
2930                         data_blocks -= overhead;
2931                 }
2932
2933 #ifdef RESIZE2FS_DEBUG
2934                 if (flags & RESIZE_DEBUG_MIN_CALC)
2935                         printf("Added %d extra group(s), "
2936                                "blks_needed %llu, data_blocks %llu, "
2937                                "last_start %llu\n", extra_grps, blks_needed,
2938                                data_blocks, last_start);
2939 #endif
2940         }
2941
2942         /* now for the fun voodoo */
2943         grp = groups - 1;
2944         if (ext2fs_has_feature_flex_bg(fs->super) &&
2945             (grp & ~(flexbg_size - 1)) == 0)
2946                 grp = grp & ~(flexbg_size - 1);
2947         overhead = 0;
2948         for (; grp < flex_groups; grp++)
2949                 overhead += calc_group_overhead(fs, grp, old_desc_blocks);
2950
2951 #ifdef RESIZE2FS_DEBUG
2952         if (flags & RESIZE_DEBUG_MIN_CALC)
2953                 printf("Last group's overhead is %llu\n", overhead);
2954 #endif
2955
2956         /*
2957          * if this is the case then the last group is going to have data in it
2958          * so we need to adjust the size of the last group accordingly
2959          */
2960         if (last_start < blks_needed) {
2961                 blk64_t remainder = blks_needed - last_start;
2962
2963 #ifdef RESIZE2FS_DEBUG
2964                 if (flags & RESIZE_DEBUG_MIN_CALC)
2965                         printf("Need %llu data blocks in last group\n",
2966                                remainder);
2967 #endif
2968                 /*
2969                  * 50 is a magic number that mkfs/resize uses to see if its
2970                  * even worth making/resizing the fs.  basically you need to
2971                  * have at least 50 blocks in addition to the blocks needed
2972                  * for the metadata in the last group
2973                  */
2974                 if (remainder > 50)
2975                         overhead += remainder;
2976                 else
2977                         overhead += 50;
2978         } else
2979                 overhead += 50;
2980
2981         overhead += fs->super->s_first_data_block;
2982 #ifdef RESIZE2FS_DEBUG
2983         if (flags & RESIZE_DEBUG_MIN_CALC)
2984                 printf("Final size of last group is %lld\n", overhead);
2985 #endif
2986
2987         /* Add extra slack for bigalloc file systems */
2988         if (EXT2FS_CLUSTER_RATIO(fs) > 1)
2989                 overhead += EXT2FS_CLUSTER_RATIO(fs) * 2;
2990
2991         /*
2992          * since our last group doesn't have to be BLOCKS_PER_GROUP
2993          * large, we only do groups-1, and then add the number of
2994          * blocks needed to handle the group descriptor metadata+data
2995          * that we need
2996          */
2997         blks_needed = EXT2_GROUPS_TO_BLOCKS(fs->super, groups - 1);
2998         blks_needed += overhead;
2999
3000         /*
3001          * Make sure blks_needed covers the end of the inode table in
3002          * the last block group.
3003          */
3004         overhead = ext2fs_inode_table_loc(fs, groups-1) +
3005                 fs->inode_blocks_per_group;
3006         if (blks_needed < overhead)
3007                 blks_needed = overhead;
3008
3009 #ifdef RESIZE2FS_DEBUG
3010         if (flags & RESIZE_DEBUG_MIN_CALC)
3011                 printf("Estimated blocks needed: %llu\n", blks_needed);
3012 #endif
3013
3014         /*
3015          * If at this point we've already added up more "needed" than
3016          * the current size, just return current size as minimum.
3017          */
3018         if (blks_needed >= ext2fs_blocks_count(fs->super))
3019                 return ext2fs_blocks_count(fs->super);
3020         /*
3021          * We need to reserve a few extra blocks if extents are
3022          * enabled, in case we need to grow the extent tree.  The more
3023          * we shrink the file system, the more space we need.
3024          *
3025          * The absolute worst case is every single data block is in
3026          * the part of the file system that needs to be evacuated,
3027          * with each data block needs to be in its own extent, and
3028          * with each inode needing at least one extent block.
3029          */
3030         if (ext2fs_has_feature_extents(fs->super)) {
3031                 blk64_t safe_margin = (ext2fs_blocks_count(fs->super) -
3032                                        blks_needed)/500;
3033                 unsigned int exts_per_blk = (fs->blocksize /
3034                                              sizeof(struct ext3_extent)) - 1;
3035                 blk64_t worst_case = ((data_needed + exts_per_blk - 1) /
3036                                       exts_per_blk);
3037
3038                 if (worst_case < inode_count)
3039                         worst_case = inode_count;
3040
3041                 if (safe_margin > worst_case)
3042                         safe_margin = worst_case;
3043
3044 #ifdef RESIZE2FS_DEBUG
3045                 if (flags & RESIZE_DEBUG_MIN_CALC)
3046                         printf("Extents safety margin: %llu\n", safe_margin);
3047 #endif
3048                 blks_needed += safe_margin;
3049         }
3050
3051         return blks_needed;
3052 }