fs/ext3/resize.c

   1 /*
   2  *  linux/fs/ext3/resize.c
   3  *
   4  * Support for resizing an ext3 filesystem while it is mounted.
   5  *
   6  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   7  *
   8  * This could probably be made into a module, because it is not often in use.
   9  */
  10
  11
  12 #define EXT3FS_DEBUG
  13
  14 #include <linux/smp_lock.h>
  15 #include <linux/ext3_jbd.h>
  16
  17 #include <linux/errno.h>
  18 #include <linux/slab.h>
  19
  20
  21 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
  22 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  23
  24 static int verify_group_input(struct super_block *sb,
  25                               struct ext3_new_group_data *input)
  26 {
  27         struct ext3_sb_info *sbi = EXT3_SB(sb);
  28         struct ext3_super_block *es = sbi->s_es;
  29         ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
  30         ext3_fsblk_t end = start + input->blocks_count;
  31         unsigned group = input->group;
  32         ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  33         unsigned overhead = ext3_bg_has_super(sb, group) ?
  34                 (1 + ext3_bg_num_gdb(sb, group) +
  35                  le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
  36         ext3_fsblk_t metaend = start + overhead;
  37         struct buffer_head *bh = NULL;
  38         ext3_grpblk_t free_blocks_count;
  39         int err = -EINVAL;
  40
  41         input->free_blocks_count = free_blocks_count =
  42                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
  43
  44         if (test_opt(sb, DEBUG))
  45                 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
  46                        "(%d free, %u reserved)\n",
  47                        ext3_bg_has_super(sb, input->group) ? "normal" :
  48                        "no-super", input->group, input->blocks_count,
  49                        free_blocks_count, input->reserved_blocks);
  50
  51         if (group != sbi->s_groups_count)
  52                 ext3_warning(sb, __FUNCTION__,
  53                              "Cannot add at group %u (only %lu groups)",
  54                              input->group, sbi->s_groups_count);
  55         else if ((start - le32_to_cpu(es->s_first_data_block)) %
  56                  EXT3_BLOCKS_PER_GROUP(sb))
  57                 ext3_warning(sb, __FUNCTION__, "Last group not full");
  58         else if (input->reserved_blocks > input->blocks_count / 5)
  59                 ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
  60                              input->reserved_blocks);
  61         else if (free_blocks_count < 0)
  62                 ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
  63                              input->blocks_count);
  64         else if (!(bh = sb_bread(sb, end - 1)))
  65                 ext3_warning(sb, __FUNCTION__,
  66                              "Cannot read last block ("E3FSBLK")",
  67                              end - 1);
  68         else if (outside(input->block_bitmap, start, end))
  69                 ext3_warning(sb, __FUNCTION__,
  70                              "Block bitmap not in group (block %u)",
  71                              input->block_bitmap);
  72         else if (outside(input->inode_bitmap, start, end))
  73                 ext3_warning(sb, __FUNCTION__,
  74                              "Inode bitmap not in group (block %u)",
  75                              input->inode_bitmap);
  76         else if (outside(input->inode_table, start, end) ||
  77                  outside(itend - 1, start, end))
  78                 ext3_warning(sb, __FUNCTION__,
  79                              "Inode table not in group (blocks %u-"E3FSBLK")",
  80                              input->inode_table, itend - 1);
  81         else if (input->inode_bitmap == input->block_bitmap)
  82                 ext3_warning(sb, __FUNCTION__,
  83                              "Block bitmap same as inode bitmap (%u)",
  84                              input->block_bitmap);
  85         else if (inside(input->block_bitmap, input->inode_table, itend))
  86                 ext3_warning(sb, __FUNCTION__,
  87                              "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
  88                              input->block_bitmap, input->inode_table, itend-1);
  89         else if (inside(input->inode_bitmap, input->inode_table, itend))
  90                 ext3_warning(sb, __FUNCTION__,
  91                              "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
  92                              input->inode_bitmap, input->inode_table, itend-1);
  93         else if (inside(input->block_bitmap, start, metaend))
  94                 ext3_warning(sb, __FUNCTION__,
  95                              "Block bitmap (%u) in GDT table"
  96                              " ("E3FSBLK"-"E3FSBLK")",
  97                              input->block_bitmap, start, metaend - 1);
  98         else if (inside(input->inode_bitmap, start, metaend))
  99                 ext3_warning(sb, __FUNCTION__,
 100                              "Inode bitmap (%u) in GDT table"
 101                              " ("E3FSBLK"-"E3FSBLK")",
 102                              input->inode_bitmap, start, metaend - 1);
 103         else if (inside(input->inode_table, start, metaend) ||
 104                  inside(itend - 1, start, metaend))
 105                 ext3_warning(sb, __FUNCTION__,
 106                              "Inode table (%u-"E3FSBLK") overlaps"
 107                              "GDT table ("E3FSBLK"-"E3FSBLK")",
 108                              input->inode_table, itend - 1, start, metaend - 1);
 109         else
 110                 err = 0;
 111         brelse(bh);
 112
 113         return err;
 114 }
 115
 116 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 117                                   ext3_fsblk_t blk)
 118 {
 119         struct buffer_head *bh;
 120         int err;
 121
 122         bh = sb_getblk(sb, blk);
 123         if (!bh)
 124                 return ERR_PTR(-EIO);
 125         if ((err = ext3_journal_get_write_access(handle, bh))) {
 126                 brelse(bh);
 127                 bh = ERR_PTR(err);
 128         } else {
 129                 lock_buffer(bh);
 130                 memset(bh->b_data, 0, sb->s_blocksize);
 131                 set_buffer_uptodate(bh);
 132                 unlock_buffer(bh);
 133         }
 134
 135         return bh;
 136 }
 137
 138 /*
 139  * To avoid calling the atomic setbit hundreds or thousands of times, we only
 140  * need to use it within a single byte (to ensure we get endianness right).
 141  * We can use memset for the rest of the bitmap as there are no other users.
 142  */
 143 static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 144 {
 145         int i;
 146
 147         if (start_bit >= end_bit)
 148                 return;
 149
 150         ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
 151         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
 152                 ext3_set_bit(i, bitmap);
 153         if (i < end_bit)
 154                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
 155 }
 156
 157 /*
 158  * Set up the block and inode bitmaps, and the inode table for the new group.
 159  * This doesn't need to be part of the main transaction, since we are only
 160  * changing blocks outside the actual filesystem.  We still do journaling to
 161  * ensure the recovery is correct in case of a failure just after resize.
 162  * If any part of this fails, we simply abort the resize.
 163  */
 164 static int setup_new_group_blocks(struct super_block *sb,
 165                                   struct ext3_new_group_data *input)
 166 {
 167         struct ext3_sb_info *sbi = EXT3_SB(sb);
 168         ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
 169         int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
 170                 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
 171         unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
 172         struct buffer_head *bh;
 173         handle_t *handle;
 174         ext3_fsblk_t block;
 175         ext3_grpblk_t bit;
 176         int i;
 177         int err = 0, err2;
 178
 179         handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
 180                                        2 + sbi->s_itb_per_group);
 181         if (IS_ERR(handle))
 182                 return PTR_ERR(handle);
 183
 184         lock_super(sb);
 185         if (input->group != sbi->s_groups_count) {
 186                 err = -EBUSY;
 187                 goto exit_journal;
 188         }
 189
 190         if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
 191                 err = PTR_ERR(bh);
 192                 goto exit_journal;
 193         }
 194
 195         if (ext3_bg_has_super(sb, input->group)) {
 196                 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
 197                 ext3_set_bit(0, bh->b_data);
 198         }
 199
 200         /* Copy all of the GDT blocks into the backup in this group */
 201         for (i = 0, bit = 1, block = start + 1;
 202              i < gdblocks; i++, block++, bit++) {
 203                 struct buffer_head *gdb;
 204
 205                 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
 206
 207                 gdb = sb_getblk(sb, block);
 208                 if (!gdb) {
 209                         err = -EIO;
 210                         goto exit_bh;
 211                 }
 212                 if ((err = ext3_journal_get_write_access(handle, gdb))) {
 213                         brelse(gdb);
 214                         goto exit_bh;
 215                 }
 216                 lock_buffer(bh);
 217                 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
 218                 set_buffer_uptodate(gdb);
 219                 unlock_buffer(bh);
 220                 ext3_journal_dirty_metadata(handle, gdb);
 221                 ext3_set_bit(bit, bh->b_data);
 222                 brelse(gdb);
 223         }
 224
 225         /* Zero out all of the reserved backup group descriptor table blocks */
 226         for (i = 0, bit = gdblocks + 1, block = start + bit;
 227              i < reserved_gdb; i++, block++, bit++) {
 228                 struct buffer_head *gdb;
 229
 230                 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
 231
 232                 if (IS_ERR(gdb = bclean(handle, sb, block))) {
 233                         err = PTR_ERR(bh);
 234                         goto exit_bh;
 235                 }
 236                 ext3_journal_dirty_metadata(handle, gdb);
 237                 ext3_set_bit(bit, bh->b_data);
 238                 brelse(gdb);
 239         }
 240         ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
 241                    input->block_bitmap - start);
 242         ext3_set_bit(input->block_bitmap - start, bh->b_data);
 243         ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
 244                    input->inode_bitmap - start);
 245         ext3_set_bit(input->inode_bitmap - start, bh->b_data);
 246
 247         /* Zero out all of the inode table blocks */
 248         for (i = 0, block = input->inode_table, bit = block - start;
 249              i < sbi->s_itb_per_group; i++, bit++, block++) {
 250                 struct buffer_head *it;
 251
 252                 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
 253                 if (IS_ERR(it = bclean(handle, sb, block))) {
 254                         err = PTR_ERR(it);
 255                         goto exit_bh;
 256                 }
 257                 ext3_journal_dirty_metadata(handle, it);
 258                 brelse(it);
 259                 ext3_set_bit(bit, bh->b_data);
 260         }
 261         mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
 262                         bh->b_data);
 263         ext3_journal_dirty_metadata(handle, bh);
 264         brelse(bh);
 265
 266         /* Mark unused entries in inode bitmap used */
 267         ext3_debug("clear inode bitmap %#04x (+%ld)\n",
 268                    input->inode_bitmap, input->inode_bitmap - start);
 269         if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
 270                 err = PTR_ERR(bh);
 271                 goto exit_journal;
 272         }
 273
 274         mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
 275                         bh->b_data);
 276         ext3_journal_dirty_metadata(handle, bh);
 277 exit_bh:
 278         brelse(bh);
 279
 280 exit_journal:
 281         unlock_super(sb);
 282         if ((err2 = ext3_journal_stop(handle)) && !err)
 283                 err = err2;
 284
 285         return err;
 286 }
 287
 288 /*
 289  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 290  * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
 291  * calling this for the first time.  In a sparse filesystem it will be the
 292  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 293  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 294  */
 295 static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
 296                                   unsigned *five, unsigned *seven)
 297 {
 298         unsigned *min = three;
 299         int mult = 3;
 300         unsigned ret;
 301
 302         if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
 303                                         EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 304                 ret = *min;
 305                 *min += 1;
 306                 return ret;
 307         }
 308
 309         if (*five < *min) {
 310                 min = five;
 311                 mult = 5;
 312         }
 313         if (*seven < *min) {
 314                 min = seven;
 315                 mult = 7;
 316         }
 317
 318         ret = *min;
 319         *min *= mult;
 320
 321         return ret;
 322 }
 323
 324 /*
 325  * Check that all of the backup GDT blocks are held in the primary GDT block.
 326  * It is assumed that they are stored in group order.  Returns the number of
 327  * groups in current filesystem that have BACKUPS, or -ve error code.
 328  */
 329 static int verify_reserved_gdb(struct super_block *sb,
 330                                struct buffer_head *primary)
 331 {
 332         const ext3_fsblk_t blk = primary->b_blocknr;
 333         const unsigned long end = EXT3_SB(sb)->s_groups_count;
 334         unsigned three = 1;
 335         unsigned five = 5;
 336         unsigned seven = 7;
 337         unsigned grp;
 338         __le32 *p = (__le32 *)primary->b_data;
 339         int gdbackups = 0;
 340
 341         while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
 342                 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
 343                         ext3_warning(sb, __FUNCTION__,
 344                                      "reserved GDT "E3FSBLK
 345                                      " missing grp %d ("E3FSBLK")",
 346                                      blk, grp,
 347                                      grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
 348                         return -EINVAL;
 349                 }
 350                 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
 351                         return -EFBIG;
 352         }
 353
 354         return gdbackups;
 355 }
 356
 357 /*
 358  * Called when we need to bring a reserved group descriptor table block into
 359  * use from the resize inode.  The primary copy of the new GDT block currently
 360  * is an indirect block (under the double indirect block in the resize inode).
 361  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 362  * block, in group order.  Even though we know all the block numbers we need,
 363  * we check to ensure that the resize inode has actually reserved these blocks.
 364  *
 365  * Don't need to update the block bitmaps because the blocks are still in use.
 366  *
 367  * We get all of the error cases out of the way, so that we are sure to not
 368  * fail once we start modifying the data on disk, because JBD has no rollback.
 369  */
 370 static int add_new_gdb(handle_t *handle, struct inode *inode,
 371                        struct ext3_new_group_data *input,
 372                        struct buffer_head **primary)
 373 {
 374         struct super_block *sb = inode->i_sb;
 375         struct ext3_super_block *es = EXT3_SB(sb)->s_es;
 376         unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
 377         ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 378         struct buffer_head **o_group_desc, **n_group_desc;
 379         struct buffer_head *dind;
 380         int gdbackups;
 381         struct ext3_iloc iloc;
 382         __le32 *data;
 383         int err;
 384
 385         if (test_opt(sb, DEBUG))
 386                 printk(KERN_DEBUG
 387                        "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
 388                        gdb_num);
 389
 390         /*
 391          * If we are not using the primary superblock/GDT copy don't resize,
 392          * because the user tools have no way of handling this.  Probably a
 393          * bad time to do it anyways.
 394          */
 395         if (EXT3_SB(sb)->s_sbh->b_blocknr !=
 396             le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
 397                 ext3_warning(sb, __FUNCTION__,
 398                         "won't resize using backup superblock at %llu",
 399                         (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
 400                 return -EPERM;
 401         }
 402
 403         *primary = sb_bread(sb, gdblock);
 404         if (!*primary)
 405                 return -EIO;
 406
 407         if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
 408                 err = gdbackups;
 409                 goto exit_bh;
 410         }
 411
 412         data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
 413         dind = sb_bread(sb, le32_to_cpu(*data));
 414         if (!dind) {
 415                 err = -EIO;
 416                 goto exit_bh;
 417         }
 418
 419         data = (__le32 *)dind->b_data;
 420         if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
 421                 ext3_warning(sb, __FUNCTION__,
 422                              "new group %u GDT block "E3FSBLK" not reserved",
 423                              input->group, gdblock);
 424                 err = -EINVAL;
 425                 goto exit_dind;
 426         }
 427
 428         if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
 429                 goto exit_dind;
 430
 431         if ((err = ext3_journal_get_write_access(handle, *primary)))
 432                 goto exit_sbh;
 433
 434         if ((err = ext3_journal_get_write_access(handle, dind)))
 435                 goto exit_primary;
 436
 437         /* ext3_reserve_inode_write() gets a reference on the iloc */
 438         if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
 439                 goto exit_dindj;
 440
 441         n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 442                         GFP_KERNEL);
 443         if (!n_group_desc) {
 444                 err = -ENOMEM;
 445                 ext3_warning (sb, __FUNCTION__,
 446                               "not enough memory for %lu groups", gdb_num + 1);
 447                 goto exit_inode;
 448         }
 449
 450         /*
 451          * Finally, we have all of the possible failures behind us...
 452          *
 453          * Remove new GDT block from inode double-indirect block and clear out
 454          * the new GDT block for use (which also "frees" the backup GDT blocks
 455          * from the reserved inode).  We don't need to change the bitmaps for
 456          * these blocks, because they are marked as in-use from being in the
 457          * reserved inode, and will become GDT blocks (primary and backup).
 458          */
 459         data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
 460         ext3_journal_dirty_metadata(handle, dind);
 461         brelse(dind);
 462         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 463         ext3_mark_iloc_dirty(handle, inode, &iloc);
 464         memset((*primary)->b_data, 0, sb->s_blocksize);
 465         ext3_journal_dirty_metadata(handle, *primary);
 466
 467         o_group_desc = EXT3_SB(sb)->s_group_desc;
 468         memcpy(n_group_desc, o_group_desc,
 469                EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 470         n_group_desc[gdb_num] = *primary;
 471         EXT3_SB(sb)->s_group_desc = n_group_desc;
 472         EXT3_SB(sb)->s_gdb_count++;
 473         kfree(o_group_desc);
 474
 475         es->s_reserved_gdt_blocks =
 476                 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
 477         ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
 478
 479         return 0;
 480
 481 exit_inode:
 482         //ext3_journal_release_buffer(handle, iloc.bh);
 483         brelse(iloc.bh);
 484 exit_dindj:
 485         //ext3_journal_release_buffer(handle, dind);
 486 exit_primary:
 487         //ext3_journal_release_buffer(handle, *primary);
 488 exit_sbh:
 489         //ext3_journal_release_buffer(handle, *primary);
 490 exit_dind:
 491         brelse(dind);
 492 exit_bh:
 493         brelse(*primary);
 494
 495         ext3_debug("leaving with error %d\n", err);
 496         return err;
 497 }
 498
 499 /*
 500  * Called when we are adding a new group which has a backup copy of each of
 501  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 502  * We need to add these reserved backup GDT blocks to the resize inode, so
 503  * that they are kept for future resizing and not allocated to files.
 504  *
 505  * Each reserved backup GDT block will go into a different indirect block.
 506  * The indirect blocks are actually the primary reserved GDT blocks,
 507  * so we know in advance what their block numbers are.  We only get the
 508  * double-indirect block to verify it is pointing to the primary reserved
 509  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 510  * backup GDT blocks are stored in their reserved primary GDT block.
 511  */
 512 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 513                               struct ext3_new_group_data *input)
 514 {
 515         struct super_block *sb = inode->i_sb;
 516         int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
 517         struct buffer_head **primary;
 518         struct buffer_head *dind;
 519         struct ext3_iloc iloc;
 520         ext3_fsblk_t blk;
 521         __le32 *data, *end;
 522         int gdbackups = 0;
 523         int res, i;
 524         int err;
 525
 526         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
 527         if (!primary)
 528                 return -ENOMEM;
 529
 530         data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
 531         dind = sb_bread(sb, le32_to_cpu(*data));
 532         if (!dind) {
 533                 err = -EIO;
 534                 goto exit_free;
 535         }
 536
 537         blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
 538         data = (__le32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
 539         end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
 540
 541         /* Get each reserved primary GDT block and verify it holds backups */
 542         for (res = 0; res < reserved_gdb; res++, blk++) {
 543                 if (le32_to_cpu(*data) != blk) {
 544                         ext3_warning(sb, __FUNCTION__,
 545                                      "reserved block "E3FSBLK
 546                                      " not at offset %ld",
 547                                      blk,
 548                                      (long)(data - (__le32 *)dind->b_data));
 549                         err = -EINVAL;
 550                         goto exit_bh;
 551                 }
 552                 primary[res] = sb_bread(sb, blk);
 553                 if (!primary[res]) {
 554                         err = -EIO;
 555                         goto exit_bh;
 556                 }
 557                 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
 558                         brelse(primary[res]);
 559                         err = gdbackups;
 560                         goto exit_bh;
 561                 }
 562                 if (++data >= end)
 563                         data = (__le32 *)dind->b_data;
 564         }
 565
 566         for (i = 0; i < reserved_gdb; i++) {
 567                 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
 568                         /*
 569                         int j;
 570                         for (j = 0; j < i; j++)
 571                                 ext3_journal_release_buffer(handle, primary[j]);
 572                          */
 573                         goto exit_bh;
 574                 }
 575         }
 576
 577         if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
 578                 goto exit_bh;
 579
 580         /*
 581          * Finally we can add each of the reserved backup GDT blocks from
 582          * the new group to its reserved primary GDT block.
 583          */
 584         blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
 585         for (i = 0; i < reserved_gdb; i++) {
 586                 int err2;
 587                 data = (__le32 *)primary[i]->b_data;
 588                 /* printk("reserving backup %lu[%u] = %lu\n",
 589                        primary[i]->b_blocknr, gdbackups,
 590                        blk + primary[i]->b_blocknr); */
 591                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 592                 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
 593                 if (!err)
 594                         err = err2;
 595         }
 596         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
 597         ext3_mark_iloc_dirty(handle, inode, &iloc);
 598
 599 exit_bh:
 600         while (--res >= 0)
 601                 brelse(primary[res]);
 602         brelse(dind);
 603
 604 exit_free:
 605         kfree(primary);
 606
 607         return err;
 608 }
 609
 610 /*
 611  * Update the backup copies of the ext3 metadata.  These don't need to be part
 612  * of the main resize transaction, because e2fsck will re-write them if there
 613  * is a problem (basically only OOM will cause a problem).  However, we
 614  * _should_ update the backups if possible, in case the primary gets trashed
 615  * for some reason and we need to run e2fsck from a backup superblock.  The
 616  * important part is that the new block and inode counts are in the backup
 617  * superblocks, and the location of the new group metadata in the GDT backups.
 618  *
 619  * We do not need lock_super() for this, because these blocks are not
 620  * otherwise touched by the filesystem code when it is mounted.  We don't
 621  * need to worry about last changing from sbi->s_groups_count, because the
 622  * worst that can happen is that we do not copy the full number of backups
 623  * at this time.  The resize which changed s_groups_count will backup again.
 624  */
 625 static void update_backups(struct super_block *sb,
 626                            int blk_off, char *data, int size)
 627 {
 628         struct ext3_sb_info *sbi = EXT3_SB(sb);
 629         const unsigned long last = sbi->s_groups_count;
 630         const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
 631         unsigned three = 1;
 632         unsigned five = 5;
 633         unsigned seven = 7;
 634         unsigned group;
 635         int rest = sb->s_blocksize - size;
 636         handle_t *handle;
 637         int err = 0, err2;
 638
 639         handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
 640         if (IS_ERR(handle)) {
 641                 group = 1;
 642                 err = PTR_ERR(handle);
 643                 goto exit_err;
 644         }
 645
 646         while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
 647                 struct buffer_head *bh;
 648
 649                 /* Out of journal space, and can't get more - abort - so sad */
 650                 if (handle->h_buffer_credits == 0 &&
 651                     ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
 652                     (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
 653                         break;
 654
 655                 bh = sb_getblk(sb, group * bpg + blk_off);
 656                 if (!bh) {
 657                         err = -EIO;
 658                         break;
 659                 }
 660                 ext3_debug("update metadata backup %#04lx\n",
 661                           (unsigned long)bh->b_blocknr);
 662                 if ((err = ext3_journal_get_write_access(handle, bh)))
 663                         break;
 664                 lock_buffer(bh);
 665                 memcpy(bh->b_data, data, size);
 666                 if (rest)
 667                         memset(bh->b_data + size, 0, rest);
 668                 set_buffer_uptodate(bh);
 669                 unlock_buffer(bh);
 670                 ext3_journal_dirty_metadata(handle, bh);
 671                 brelse(bh);
 672         }
 673         if ((err2 = ext3_journal_stop(handle)) && !err)
 674                 err = err2;
 675
 676         /*
 677          * Ugh! Need to have e2fsck write the backup copies.  It is too
 678          * late to revert the resize, we shouldn't fail just because of
 679          * the backup copies (they are only needed in case of corruption).
 680          *
 681          * However, if we got here we have a journal problem too, so we
 682          * can't really start a transaction to mark the superblock.
 683          * Chicken out and just set the flag on the hope it will be written
 684          * to disk, and if not - we will simply wait until next fsck.
 685          */
 686 exit_err:
 687         if (err) {
 688                 ext3_warning(sb, __FUNCTION__,
 689                              "can't update backup for group %d (err %d), "
 690                              "forcing fsck on next reboot", group, err);
 691                 sbi->s_mount_state &= ~EXT3_VALID_FS;
 692                 sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
 693                 mark_buffer_dirty(sbi->s_sbh);
 694         }
 695 }
 696
 697 /* Add group descriptor data to an existing or new group descriptor block.
 698  * Ensure we handle all possible error conditions _before_ we start modifying
 699  * the filesystem, because we cannot abort the transaction and not have it
 700  * write the data to disk.
 701  *
 702  * If we are on a GDT block boundary, we need to get the reserved GDT block.
 703  * Otherwise, we may need to add backup GDT blocks for a sparse group.
 704  *
 705  * We only need to hold the superblock lock while we are actually adding
 706  * in the new group's counts to the superblock.  Prior to that we have
 707  * not really "added" the group at all.  We re-check that we are still
 708  * adding in the last group in case things have changed since verifying.
 709  */
 710 int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
 711 {
 712         struct ext3_sb_info *sbi = EXT3_SB(sb);
 713         struct ext3_super_block *es = sbi->s_es;
 714         int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
 715                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
 716         struct buffer_head *primary = NULL;
 717         struct ext3_group_desc *gdp;
 718         struct inode *inode = NULL;
 719         handle_t *handle;
 720         int gdb_off, gdb_num;
 721         int err, err2;
 722
 723         gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
 724         gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
 725
 726         if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
 727                                         EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 728                 ext3_warning(sb, __FUNCTION__,
 729                              "Can't resize non-sparse filesystem further");
 730                 return -EPERM;
 731         }
 732
 733         if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
 734             le32_to_cpu(es->s_blocks_count)) {
 735                 ext3_warning(sb, __FUNCTION__, "blocks_count overflow\n");
 736                 return -EINVAL;
 737         }
 738
 739         if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
 740             le32_to_cpu(es->s_inodes_count)) {
 741                 ext3_warning(sb, __FUNCTION__, "inodes_count overflow\n");
 742                 return -EINVAL;
 743         }
 744
 745         if (reserved_gdb || gdb_off == 0) {
 746                 if (!EXT3_HAS_COMPAT_FEATURE(sb,
 747                                              EXT3_FEATURE_COMPAT_RESIZE_INODE)){
 748                         ext3_warning(sb, __FUNCTION__,
 749                                      "No reserved GDT blocks, can't resize");
 750                         return -EPERM;
 751                 }
 752                 inode = iget(sb, EXT3_RESIZE_INO);
 753                 if (!inode || is_bad_inode(inode)) {
 754                         ext3_warning(sb, __FUNCTION__,
 755                                      "Error opening resize inode");
 756                         iput(inode);
 757                         return -ENOENT;
 758                 }
 759         }
 760
 761         if ((err = verify_group_input(sb, input)))
 762                 goto exit_put;
 763
 764         if ((err = setup_new_group_blocks(sb, input)))
 765                 goto exit_put;
 766
 767         /*
 768          * We will always be modifying at least the superblock and a GDT
 769          * block.  If we are adding a group past the last current GDT block,
 770          * we will also modify the inode and the dindirect block.  If we
 771          * are adding a group with superblock/GDT backups  we will also
 772          * modify each of the reserved GDT dindirect blocks.
 773          */
 774         handle = ext3_journal_start_sb(sb,
 775                                        ext3_bg_has_super(sb, input->group) ?
 776                                        3 + reserved_gdb : 4);
 777         if (IS_ERR(handle)) {
 778                 err = PTR_ERR(handle);
 779                 goto exit_put;
 780         }
 781
 782         lock_super(sb);
 783         if (input->group != sbi->s_groups_count) {
 784                 ext3_warning(sb, __FUNCTION__,
 785                              "multiple resizers run on filesystem!");
 786                 err = -EBUSY;
 787                 goto exit_journal;
 788         }
 789
 790         if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
 791                 goto exit_journal;
 792
 793         /*
 794          * We will only either add reserved group blocks to a backup group
 795          * or remove reserved blocks for the first group in a new group block.
 796          * Doing both would be mean more complex code, and sane people don't
 797          * use non-sparse filesystems anymore.  This is already checked above.
 798          */
 799         if (gdb_off) {
 800                 primary = sbi->s_group_desc[gdb_num];
 801                 if ((err = ext3_journal_get_write_access(handle, primary)))
 802                         goto exit_journal;
 803
 804                 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
 805                     (err = reserve_backup_gdb(handle, inode, input)))
 806                         goto exit_journal;
 807         } else if ((err = add_new_gdb(handle, inode, input, &primary)))
 808                 goto exit_journal;
 809
 810         /*
 811          * OK, now we've set up the new group.  Time to make it active.
 812          *
 813          * Current kernels don't lock all allocations via lock_super(),
 814          * so we have to be safe wrt. concurrent accesses the group
 815          * data.  So we need to be careful to set all of the relevant
 816          * group descriptor data etc. *before* we enable the group.
 817          *
 818          * The key field here is sbi->s_groups_count: as long as
 819          * that retains its old value, nobody is going to access the new
 820          * group.
 821          *
 822          * So first we update all the descriptor metadata for the new
 823          * group; then we update the total disk blocks count; then we
 824          * update the groups count to enable the group; then finally we
 825          * update the free space counts so that the system can start
 826          * using the new disk blocks.
 827          */
 828
 829         /* Update group descriptor block for new group */
 830         gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
 831
 832         gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
 833         gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
 834         gdp->bg_inode_table = cpu_to_le32(input->inode_table);
 835         gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
 836         gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
 837
 838         /*
 839          * Make the new blocks and inodes valid next.  We do this before
 840          * increasing the group count so that once the group is enabled,
 841          * all of its blocks and inodes are already valid.
 842          *
 843          * We always allocate group-by-group, then block-by-block or
 844          * inode-by-inode within a group, so enabling these
 845          * blocks/inodes before the group is live won't actually let us
 846          * allocate the new space yet.
 847          */
 848         es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
 849                 input->blocks_count);
 850         es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
 851                 EXT3_INODES_PER_GROUP(sb));
 852
 853         /*
 854          * We need to protect s_groups_count against other CPUs seeing
 855          * inconsistent state in the superblock.
 856          *
 857          * The precise rules we use are:
 858          *
 859          * * Writers of s_groups_count *must* hold lock_super
 860          * AND
 861          * * Writers must perform a smp_wmb() after updating all dependent
 862          *   data and before modifying the groups count
 863          *
 864          * * Readers must hold lock_super() over the access
 865          * OR
 866          * * Readers must perform an smp_rmb() after reading the groups count
 867          *   and before reading any dependent data.
 868          *
 869          * NB. These rules can be relaxed when checking the group count
 870          * while freeing data, as we can only allocate from a block
 871          * group after serialising against the group count, and we can
 872          * only then free after serialising in turn against that
 873          * allocation.
 874          */
 875         smp_wmb();
 876
 877         /* Update the global fs size fields */
 878         sbi->s_groups_count++;
 879
 880         ext3_journal_dirty_metadata(handle, primary);
 881
 882         /* Update the reserved block counts only once the new group is
 883          * active. */
 884         es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
 885                 input->reserved_blocks);
 886
 887         /* Update the free space counts */
 888         percpu_counter_mod(&sbi->s_freeblocks_counter,
 889                            input->free_blocks_count);
 890         percpu_counter_mod(&sbi->s_freeinodes_counter,
 891                            EXT3_INODES_PER_GROUP(sb));
 892
 893         ext3_journal_dirty_metadata(handle, sbi->s_sbh);
 894         sb->s_dirt = 1;
 895
 896 exit_journal:
 897         unlock_super(sb);
 898         if ((err2 = ext3_journal_stop(handle)) && !err)
 899                 err = err2;
 900         if (!err) {
 901                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
 902                                sizeof(struct ext3_super_block));
 903                 update_backups(sb, primary->b_blocknr, primary->b_data,
 904                                primary->b_size);
 905         }
 906 exit_put:
 907         iput(inode);
 908         return err;
 909 } /* ext3_group_add */
 910
 911 /* Extend the filesystem to the new number of blocks specified.  This entry
 912  * point is only used to extend the current filesystem to the end of the last
 913  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
 914  * for emergencies (because it has no dependencies on reserved blocks).
 915  *
 916  * If we _really_ wanted, we could use default values to call ext3_group_add()
 917  * allow the "remount" trick to work for arbitrary resizing, assuming enough
 918  * GDT blocks are reserved to grow to the desired size.
 919  */
 920 int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
 921                       ext3_fsblk_t n_blocks_count)
 922 {
 923         ext3_fsblk_t o_blocks_count;
 924         unsigned long o_groups_count;
 925         ext3_grpblk_t last;
 926         ext3_grpblk_t add;
 927         struct buffer_head * bh;
 928         handle_t *handle;
 929         int err;
 930         unsigned long freed_blocks;
 931
 932         /* We don't need to worry about locking wrt other resizers just
 933          * yet: we're going to revalidate es->s_blocks_count after
 934          * taking lock_super() below. */
 935         o_blocks_count = le32_to_cpu(es->s_blocks_count);
 936         o_groups_count = EXT3_SB(sb)->s_groups_count;
 937
 938         if (test_opt(sb, DEBUG))
 939                 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
 940                        o_blocks_count, n_blocks_count);
 941
 942         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
 943                 return 0;
 944
 945         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
 946                 printk(KERN_ERR "EXT3-fs: filesystem on %s:"
 947                         " too large to resize to %lu blocks safely\n",
 948                         sb->s_id, n_blocks_count);
 949                 if (sizeof(sector_t) < 8)
 950                         ext3_warning(sb, __FUNCTION__,
 951                         "CONFIG_LBD not enabled\n");
 952                 return -EINVAL;
 953         }
 954
 955         if (n_blocks_count < o_blocks_count) {
 956                 ext3_warning(sb, __FUNCTION__,
 957                              "can't shrink FS - resize aborted");
 958                 return -EBUSY;
 959         }
 960
 961         /* Handle the remaining blocks in the last group only. */
 962         last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
 963                 EXT3_BLOCKS_PER_GROUP(sb);
 964
 965         if (last == 0) {
 966                 ext3_warning(sb, __FUNCTION__,
 967                              "need to use ext2online to resize further");
 968                 return -EPERM;
 969         }
 970
 971         add = EXT3_BLOCKS_PER_GROUP(sb) - last;
 972
 973         if (o_blocks_count + add < o_blocks_count) {
 974                 ext3_warning(sb, __FUNCTION__, "blocks_count overflow");
 975                 return -EINVAL;
 976         }
 977
 978         if (o_blocks_count + add > n_blocks_count)
 979                 add = n_blocks_count - o_blocks_count;
 980
 981         if (o_blocks_count + add < n_blocks_count)
 982                 ext3_warning(sb, __FUNCTION__,
 983                              "will only finish group ("E3FSBLK
 984                              " blocks, %u new)",
 985                              o_blocks_count + add, add);
 986
 987         /* See if the device is actually as big as what was requested */
 988         bh = sb_bread(sb, o_blocks_count + add -1);
 989         if (!bh) {
 990                 ext3_warning(sb, __FUNCTION__,
 991                              "can't read last block, resize aborted");
 992                 return -ENOSPC;
 993         }
 994         brelse(bh);
 995
 996         /* We will update the superblock, one block bitmap, and
 997          * one group descriptor via ext3_free_blocks().
 998          */
 999         handle = ext3_journal_start_sb(sb, 3);
1000         if (IS_ERR(handle)) {
1001                 err = PTR_ERR(handle);
1002                 ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
1003                 goto exit_put;
1004         }
1005
1006         lock_super(sb);
1007         if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
1008                 ext3_warning(sb, __FUNCTION__,
1009                              "multiple resizers run on filesystem!");
1010                 unlock_super(sb);
1011                 err = -EBUSY;
1012                 goto exit_put;
1013         }
1014
1015         if ((err = ext3_journal_get_write_access(handle,
1016                                                  EXT3_SB(sb)->s_sbh))) {
1017                 ext3_warning(sb, __FUNCTION__,
1018                              "error %d on journal write access", err);
1019                 unlock_super(sb);
1020                 ext3_journal_stop(handle);
1021                 goto exit_put;
1022         }
1023         es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
1024         ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
1025         sb->s_dirt = 1;
1026         unlock_super(sb);
1027         ext3_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
1028                    o_blocks_count + add);
1029         ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1030         ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
1031                    o_blocks_count + add);
1032         if ((err = ext3_journal_stop(handle)))
1033                 goto exit_put;
1034         if (test_opt(sb, DEBUG))
1035                 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1036                        le32_to_cpu(es->s_blocks_count));
1037         update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1038                        sizeof(struct ext3_super_block));
1039 exit_put:
1040         return err;
1041 } /* ext3_group_extend */