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 "ext3.h" 15 16 17#define outside(b, first, last) ((b) < (first) || (b) >= (last)) 18#define inside(b, first, last) ((b) >= (first) && (b) < (last)) 19 20static int verify_group_input(struct super_block *sb, 21 struct ext3_new_group_data *input) 22{ 23 struct ext3_sb_info *sbi = EXT3_SB(sb); 24 struct ext3_super_block *es = sbi->s_es; 25 ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count); 26 ext3_fsblk_t end = start + input->blocks_count; 27 unsigned group = input->group; 28 ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group; 29 unsigned overhead = ext3_bg_has_super(sb, group) ? 30 (1 + ext3_bg_num_gdb(sb, group) + 31 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0; 32 ext3_fsblk_t metaend = start + overhead; 33 struct buffer_head *bh = NULL; 34 ext3_grpblk_t free_blocks_count; 35 int err = -EINVAL; 36 37 input->free_blocks_count = free_blocks_count = 38 input->blocks_count - 2 - overhead - sbi->s_itb_per_group; 39 40 if (test_opt(sb, DEBUG)) 41 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks " 42 "(%d free, %u reserved)\n", 43 ext3_bg_has_super(sb, input->group) ? "normal" : 44 "no-super", input->group, input->blocks_count, 45 free_blocks_count, input->reserved_blocks); 46 47 if (group != sbi->s_groups_count) 48 ext3_warning(sb, __func__, 49 "Cannot add at group %u (only %lu groups)", 50 input->group, sbi->s_groups_count); 51 else if ((start - le32_to_cpu(es->s_first_data_block)) % 52 EXT3_BLOCKS_PER_GROUP(sb)) 53 ext3_warning(sb, __func__, "Last group not full"); 54 else if (input->reserved_blocks > input->blocks_count / 5) 55 ext3_warning(sb, __func__, "Reserved blocks too high (%u)", 56 input->reserved_blocks); 57 else if (free_blocks_count < 0) 58 ext3_warning(sb, __func__, "Bad blocks count %u", 59 input->blocks_count); 60 else if (!(bh = sb_bread(sb, end - 1))) 61 ext3_warning(sb, __func__, 62 "Cannot read last block ("E3FSBLK")", 63 end - 1); 64 else if (outside(input->block_bitmap, start, end)) 65 ext3_warning(sb, __func__, 66 "Block bitmap not in group (block %u)", 67 input->block_bitmap); 68 else if (outside(input->inode_bitmap, start, end)) 69 ext3_warning(sb, __func__, 70 "Inode bitmap not in group (block %u)", 71 input->inode_bitmap); 72 else if (outside(input->inode_table, start, end) || 73 outside(itend - 1, start, end)) 74 ext3_warning(sb, __func__, 75 "Inode table not in group (blocks %u-"E3FSBLK")", 76 input->inode_table, itend - 1); 77 else if (input->inode_bitmap == input->block_bitmap) 78 ext3_warning(sb, __func__, 79 "Block bitmap same as inode bitmap (%u)", 80 input->block_bitmap); 81 else if (inside(input->block_bitmap, input->inode_table, itend)) 82 ext3_warning(sb, __func__, 83 "Block bitmap (%u) in inode table (%u-"E3FSBLK")", 84 input->block_bitmap, input->inode_table, itend-1); 85 else if (inside(input->inode_bitmap, input->inode_table, itend)) 86 ext3_warning(sb, __func__, 87 "Inode bitmap (%u) in inode table (%u-"E3FSBLK")", 88 input->inode_bitmap, input->inode_table, itend-1); 89 else if (inside(input->block_bitmap, start, metaend)) 90 ext3_warning(sb, __func__, 91 "Block bitmap (%u) in GDT table" 92 " ("E3FSBLK"-"E3FSBLK")", 93 input->block_bitmap, start, metaend - 1); 94 else if (inside(input->inode_bitmap, start, metaend)) 95 ext3_warning(sb, __func__, 96 "Inode bitmap (%u) in GDT table" 97 " ("E3FSBLK"-"E3FSBLK")", 98 input->inode_bitmap, start, metaend - 1); 99 else if (inside(input->inode_table, start, metaend) || 100 inside(itend - 1, start, metaend)) 101 ext3_warning(sb, __func__, 102 "Inode table (%u-"E3FSBLK") overlaps" 103 "GDT table ("E3FSBLK"-"E3FSBLK")", 104 input->inode_table, itend - 1, start, metaend - 1); 105 else 106 err = 0; 107 brelse(bh); 108 109 return err; 110} 111 112static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, 113 ext3_fsblk_t blk) 114{ 115 struct buffer_head *bh; 116 int err; 117 118 bh = sb_getblk(sb, blk); 119 if (unlikely(!bh)) 120 return ERR_PTR(-ENOMEM); 121 if ((err = ext3_journal_get_write_access(handle, bh))) { 122 brelse(bh); 123 bh = ERR_PTR(err); 124 } else { 125 lock_buffer(bh); 126 memset(bh->b_data, 0, sb->s_blocksize); 127 set_buffer_uptodate(bh); 128 unlock_buffer(bh); 129 } 130 131 return bh; 132} 133 134/* 135 * To avoid calling the atomic setbit hundreds or thousands of times, we only 136 * need to use it within a single byte (to ensure we get endianness right). 137 * We can use memset for the rest of the bitmap as there are no other users. 138 */ 139static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap) 140{ 141 int i; 142 143 if (start_bit >= end_bit) 144 return; 145 146 ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit); 147 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++) 148 ext3_set_bit(i, bitmap); 149 if (i < end_bit) 150 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3); 151} 152 153/* 154 * If we have fewer than thresh credits, extend by EXT3_MAX_TRANS_DATA. 155 * If that fails, restart the transaction & regain write access for the 156 * buffer head which is used for block_bitmap modifications. 157 */ 158static int extend_or_restart_transaction(handle_t *handle, int thresh, 159 struct buffer_head *bh) 160{ 161 int err; 162 163 if (handle->h_buffer_credits >= thresh) 164 return 0; 165 166 err = ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA); 167 if (err < 0) 168 return err; 169 if (err) { 170 err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA); 171 if (err) 172 return err; 173 err = ext3_journal_get_write_access(handle, bh); 174 if (err) 175 return err; 176 } 177 178 return 0; 179} 180 181/* 182 * Set up the block and inode bitmaps, and the inode table for the new group. 183 * This doesn't need to be part of the main transaction, since we are only 184 * changing blocks outside the actual filesystem. We still do journaling to 185 * ensure the recovery is correct in case of a failure just after resize. 186 * If any part of this fails, we simply abort the resize. 187 */ 188static int setup_new_group_blocks(struct super_block *sb, 189 struct ext3_new_group_data *input) 190{ 191 struct ext3_sb_info *sbi = EXT3_SB(sb); 192 ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group); 193 int reserved_gdb = ext3_bg_has_super(sb, input->group) ? 194 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0; 195 unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group); 196 struct buffer_head *bh; 197 handle_t *handle; 198 ext3_fsblk_t block; 199 ext3_grpblk_t bit; 200 int i; 201 int err = 0, err2; 202 203 /* This transaction may be extended/restarted along the way */ 204 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA); 205 206 if (IS_ERR(handle)) 207 return PTR_ERR(handle); 208 209 mutex_lock(&sbi->s_resize_lock); 210 if (input->group != sbi->s_groups_count) { 211 err = -EBUSY; 212 goto exit_journal; 213 } 214 215 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) { 216 err = PTR_ERR(bh); 217 goto exit_journal; 218 } 219 220 if (ext3_bg_has_super(sb, input->group)) { 221 ext3_debug("mark backup superblock %#04lx (+0)\n", start); 222 ext3_set_bit(0, bh->b_data); 223 } 224 225 /* Copy all of the GDT blocks into the backup in this group */ 226 for (i = 0, bit = 1, block = start + 1; 227 i < gdblocks; i++, block++, bit++) { 228 struct buffer_head *gdb; 229 230 ext3_debug("update backup group %#04lx (+%d)\n", block, bit); 231 232 err = extend_or_restart_transaction(handle, 1, bh); 233 if (err) 234 goto exit_bh; 235 236 gdb = sb_getblk(sb, block); 237 if (unlikely(!gdb)) { 238 err = -ENOMEM; 239 goto exit_bh; 240 } 241 if ((err = ext3_journal_get_write_access(handle, gdb))) { 242 brelse(gdb); 243 goto exit_bh; 244 } 245 lock_buffer(gdb); 246 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size); 247 set_buffer_uptodate(gdb); 248 unlock_buffer(gdb); 249 err = ext3_journal_dirty_metadata(handle, gdb); 250 if (err) { 251 brelse(gdb); 252 goto exit_bh; 253 } 254 ext3_set_bit(bit, bh->b_data); 255 brelse(gdb); 256 } 257 258 /* Zero out all of the reserved backup group descriptor table blocks */ 259 for (i = 0, bit = gdblocks + 1, block = start + bit; 260 i < reserved_gdb; i++, block++, bit++) { 261 struct buffer_head *gdb; 262 263 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit); 264 265 err = extend_or_restart_transaction(handle, 1, bh); 266 if (err) 267 goto exit_bh; 268 269 if (IS_ERR(gdb = bclean(handle, sb, block))) { 270 err = PTR_ERR(gdb); 271 goto exit_bh; 272 } 273 err = ext3_journal_dirty_metadata(handle, gdb); 274 if (err) { 275 brelse(gdb); 276 goto exit_bh; 277 } 278 ext3_set_bit(bit, bh->b_data); 279 brelse(gdb); 280 } 281 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap, 282 input->block_bitmap - start); 283 ext3_set_bit(input->block_bitmap - start, bh->b_data); 284 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap, 285 input->inode_bitmap - start); 286 ext3_set_bit(input->inode_bitmap - start, bh->b_data); 287 288 /* Zero out all of the inode table blocks */ 289 for (i = 0, block = input->inode_table, bit = block - start; 290 i < sbi->s_itb_per_group; i++, bit++, block++) { 291 struct buffer_head *it; 292 293 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit); 294 295 err = extend_or_restart_transaction(handle, 1, bh); 296 if (err) 297 goto exit_bh; 298 299 if (IS_ERR(it = bclean(handle, sb, block))) { 300 err = PTR_ERR(it); 301 goto exit_bh; 302 } 303 err = ext3_journal_dirty_metadata(handle, it); 304 if (err) { 305 brelse(it); 306 goto exit_bh; 307 } 308 brelse(it); 309 ext3_set_bit(bit, bh->b_data); 310 } 311 312 err = extend_or_restart_transaction(handle, 2, bh); 313 if (err) 314 goto exit_bh; 315 316 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb), 317 bh->b_data); 318 err = ext3_journal_dirty_metadata(handle, bh); 319 if (err) 320 goto exit_bh; 321 brelse(bh); 322 323 /* Mark unused entries in inode bitmap used */ 324 ext3_debug("clear inode bitmap %#04x (+%ld)\n", 325 input->inode_bitmap, input->inode_bitmap - start); 326 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) { 327 err = PTR_ERR(bh); 328 goto exit_journal; 329 } 330 331 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb), 332 bh->b_data); 333 err = ext3_journal_dirty_metadata(handle, bh); 334exit_bh: 335 brelse(bh); 336 337exit_journal: 338 mutex_unlock(&sbi->s_resize_lock); 339 if ((err2 = ext3_journal_stop(handle)) && !err) 340 err = err2; 341 342 return err; 343} 344 345/* 346 * Iterate through the groups which hold BACKUP superblock/GDT copies in an 347 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before 348 * calling this for the first time. In a sparse filesystem it will be the 349 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... 350 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... 351 */ 352static unsigned ext3_list_backups(struct super_block *sb, unsigned *three, 353 unsigned *five, unsigned *seven) 354{ 355 unsigned *min = three; 356 int mult = 3; 357 unsigned ret; 358 359 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb, 360 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 361 ret = *min; 362 *min += 1; 363 return ret; 364 } 365 366 if (*five < *min) { 367 min = five; 368 mult = 5; 369 } 370 if (*seven < *min) { 371 min = seven; 372 mult = 7; 373 } 374 375 ret = *min; 376 *min *= mult; 377 378 return ret; 379} 380 381/* 382 * Check that all of the backup GDT blocks are held in the primary GDT block. 383 * It is assumed that they are stored in group order. Returns the number of 384 * groups in current filesystem that have BACKUPS, or -ve error code. 385 */ 386static int verify_reserved_gdb(struct super_block *sb, 387 struct buffer_head *primary) 388{ 389 const ext3_fsblk_t blk = primary->b_blocknr; 390 const unsigned long end = EXT3_SB(sb)->s_groups_count; 391 unsigned three = 1; 392 unsigned five = 5; 393 unsigned seven = 7; 394 unsigned grp; 395 __le32 *p = (__le32 *)primary->b_data; 396 int gdbackups = 0; 397 398 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) { 399 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){ 400 ext3_warning(sb, __func__, 401 "reserved GDT "E3FSBLK 402 " missing grp %d ("E3FSBLK")", 403 blk, grp, 404 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk); 405 return -EINVAL; 406 } 407 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb)) 408 return -EFBIG; 409 } 410 411 return gdbackups; 412} 413 414/* 415 * Called when we need to bring a reserved group descriptor table block into 416 * use from the resize inode. The primary copy of the new GDT block currently 417 * is an indirect block (under the double indirect block in the resize inode). 418 * The new backup GDT blocks will be stored as leaf blocks in this indirect 419 * block, in group order. Even though we know all the block numbers we need, 420 * we check to ensure that the resize inode has actually reserved these blocks. 421 * 422 * Don't need to update the block bitmaps because the blocks are still in use. 423 * 424 * We get all of the error cases out of the way, so that we are sure to not 425 * fail once we start modifying the data on disk, because JBD has no rollback. 426 */ 427static int add_new_gdb(handle_t *handle, struct inode *inode, 428 struct ext3_new_group_data *input, 429 struct buffer_head **primary) 430{ 431 struct super_block *sb = inode->i_sb; 432 struct ext3_super_block *es = EXT3_SB(sb)->s_es; 433 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb); 434 ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num; 435 struct buffer_head **o_group_desc, **n_group_desc; 436 struct buffer_head *dind; 437 int gdbackups; 438 struct ext3_iloc iloc; 439 __le32 *data; 440 int err; 441 442 if (test_opt(sb, DEBUG)) 443 printk(KERN_DEBUG 444 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n", 445 gdb_num); 446 447 /* 448 * If we are not using the primary superblock/GDT copy don't resize, 449 * because the user tools have no way of handling this. Probably a 450 * bad time to do it anyways. 451 */ 452 if (EXT3_SB(sb)->s_sbh->b_blocknr != 453 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) { 454 ext3_warning(sb, __func__, 455 "won't resize using backup superblock at %llu", 456 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr); 457 return -EPERM; 458 } 459 460 *primary = sb_bread(sb, gdblock); 461 if (!*primary) 462 return -EIO; 463 464 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) { 465 err = gdbackups; 466 goto exit_bh; 467 } 468 469 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK; 470 dind = sb_bread(sb, le32_to_cpu(*data)); 471 if (!dind) { 472 err = -EIO; 473 goto exit_bh; 474 } 475 476 data = (__le32 *)dind->b_data; 477 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) { 478 ext3_warning(sb, __func__, 479 "new group %u GDT block "E3FSBLK" not reserved", 480 input->group, gdblock); 481 err = -EINVAL; 482 goto exit_dind; 483 } 484 485 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh))) 486 goto exit_dind; 487 488 if ((err = ext3_journal_get_write_access(handle, *primary))) 489 goto exit_sbh; 490 491 if ((err = ext3_journal_get_write_access(handle, dind))) 492 goto exit_primary; 493 494 /* ext3_reserve_inode_write() gets a reference on the iloc */ 495 if ((err = ext3_reserve_inode_write(handle, inode, &iloc))) 496 goto exit_dindj; 497 498 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *), 499 GFP_NOFS); 500 if (!n_group_desc) { 501 err = -ENOMEM; 502 ext3_warning (sb, __func__, 503 "not enough memory for %lu groups", gdb_num + 1); 504 goto exit_inode; 505 } 506 507 /* 508 * Finally, we have all of the possible failures behind us... 509 * 510 * Remove new GDT block from inode double-indirect block and clear out 511 * the new GDT block for use (which also "frees" the backup GDT blocks 512 * from the reserved inode). We don't need to change the bitmaps for 513 * these blocks, because they are marked as in-use from being in the 514 * reserved inode, and will become GDT blocks (primary and backup). 515 */ 516 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0; 517 err = ext3_journal_dirty_metadata(handle, dind); 518 if (err) 519 goto exit_group_desc; 520 brelse(dind); 521 dind = NULL; 522 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9; 523 err = ext3_mark_iloc_dirty(handle, inode, &iloc); 524 if (err) 525 goto exit_group_desc; 526 memset((*primary)->b_data, 0, sb->s_blocksize); 527 err = ext3_journal_dirty_metadata(handle, *primary); 528 if (err) 529 goto exit_group_desc; 530 531 o_group_desc = EXT3_SB(sb)->s_group_desc; 532 memcpy(n_group_desc, o_group_desc, 533 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); 534 n_group_desc[gdb_num] = *primary; 535 EXT3_SB(sb)->s_group_desc = n_group_desc; 536 EXT3_SB(sb)->s_gdb_count++; 537 kfree(o_group_desc); 538 539 le16_add_cpu(&es->s_reserved_gdt_blocks, -1); 540 err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh); 541 if (err) 542 goto exit_inode; 543 544 return 0; 545 546exit_group_desc: 547 kfree(n_group_desc); 548exit_inode: 549 //ext3_journal_release_buffer(handle, iloc.bh); 550 brelse(iloc.bh); 551exit_dindj: 552 //ext3_journal_release_buffer(handle, dind); 553exit_primary: 554 //ext3_journal_release_buffer(handle, *primary); 555exit_sbh: 556 //ext3_journal_release_buffer(handle, *primary); 557exit_dind: 558 brelse(dind); 559exit_bh: 560 brelse(*primary); 561 562 ext3_debug("leaving with error %d\n", err); 563 return err; 564} 565 566/* 567 * Called when we are adding a new group which has a backup copy of each of 568 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks. 569 * We need to add these reserved backup GDT blocks to the resize inode, so 570 * that they are kept for future resizing and not allocated to files. 571 * 572 * Each reserved backup GDT block will go into a different indirect block. 573 * The indirect blocks are actually the primary reserved GDT blocks, 574 * so we know in advance what their block numbers are. We only get the 575 * double-indirect block to verify it is pointing to the primary reserved 576 * GDT blocks so we don't overwrite a data block by accident. The reserved 577 * backup GDT blocks are stored in their reserved primary GDT block. 578 */ 579static int reserve_backup_gdb(handle_t *handle, struct inode *inode, 580 struct ext3_new_group_data *input) 581{ 582 struct super_block *sb = inode->i_sb; 583 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks); 584 struct buffer_head **primary; 585 struct buffer_head *dind; 586 struct ext3_iloc iloc; 587 ext3_fsblk_t blk; 588 __le32 *data, *end; 589 int gdbackups = 0; 590 int res, i; 591 int err; 592 593 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS); 594 if (!primary) 595 return -ENOMEM; 596 597 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK; 598 dind = sb_bread(sb, le32_to_cpu(*data)); 599 if (!dind) { 600 err = -EIO; 601 goto exit_free; 602 } 603 604 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count; 605 data = (__le32 *)dind->b_data + (EXT3_SB(sb)->s_gdb_count % 606 EXT3_ADDR_PER_BLOCK(sb)); 607 end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb); 608 609 /* Get each reserved primary GDT block and verify it holds backups */ 610 for (res = 0; res < reserved_gdb; res++, blk++) { 611 if (le32_to_cpu(*data) != blk) { 612 ext3_warning(sb, __func__, 613 "reserved block "E3FSBLK 614 " not at offset %ld", 615 blk, 616 (long)(data - (__le32 *)dind->b_data)); 617 err = -EINVAL; 618 goto exit_bh; 619 } 620 primary[res] = sb_bread(sb, blk); 621 if (!primary[res]) { 622 err = -EIO; 623 goto exit_bh; 624 } 625 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) { 626 brelse(primary[res]); 627 err = gdbackups; 628 goto exit_bh; 629 } 630 if (++data >= end) 631 data = (__le32 *)dind->b_data; 632 } 633 634 for (i = 0; i < reserved_gdb; i++) { 635 if ((err = ext3_journal_get_write_access(handle, primary[i]))) { 636 /* 637 int j; 638 for (j = 0; j < i; j++) 639 ext3_journal_release_buffer(handle, primary[j]); 640 */ 641 goto exit_bh; 642 } 643 } 644 645 if ((err = ext3_reserve_inode_write(handle, inode, &iloc))) 646 goto exit_bh; 647 648 /* 649 * Finally we can add each of the reserved backup GDT blocks from 650 * the new group to its reserved primary GDT block. 651 */ 652 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb); 653 for (i = 0; i < reserved_gdb; i++) { 654 int err2; 655 data = (__le32 *)primary[i]->b_data; 656 /* printk("reserving backup %lu[%u] = %lu\n", 657 primary[i]->b_blocknr, gdbackups, 658 blk + primary[i]->b_blocknr); */ 659 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr); 660 err2 = ext3_journal_dirty_metadata(handle, primary[i]); 661 if (!err) 662 err = err2; 663 } 664 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9; 665 ext3_mark_iloc_dirty(handle, inode, &iloc); 666 667exit_bh: 668 while (--res >= 0) 669 brelse(primary[res]); 670 brelse(dind); 671 672exit_free: 673 kfree(primary); 674 675 return err; 676} 677 678/* 679 * Update the backup copies of the ext3 metadata. These don't need to be part 680 * of the main resize transaction, because e2fsck will re-write them if there 681 * is a problem (basically only OOM will cause a problem). However, we 682 * _should_ update the backups if possible, in case the primary gets trashed 683 * for some reason and we need to run e2fsck from a backup superblock. The 684 * important part is that the new block and inode counts are in the backup 685 * superblocks, and the location of the new group metadata in the GDT backups. 686 * 687 * We do not need take the s_resize_lock for this, because these 688 * blocks are not otherwise touched by the filesystem code when it is 689 * mounted. We don't need to worry about last changing from 690 * sbi->s_groups_count, because the worst that can happen is that we 691 * do not copy the full number of backups at this time. The resize 692 * which changed s_groups_count will backup again. 693 */ 694static void update_backups(struct super_block *sb, 695 int blk_off, char *data, int size) 696{ 697 struct ext3_sb_info *sbi = EXT3_SB(sb); 698 const unsigned long last = sbi->s_groups_count; 699 const int bpg = EXT3_BLOCKS_PER_GROUP(sb); 700 unsigned three = 1; 701 unsigned five = 5; 702 unsigned seven = 7; 703 unsigned group; 704 int rest = sb->s_blocksize - size; 705 handle_t *handle; 706 int err = 0, err2; 707 708 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA); 709 if (IS_ERR(handle)) { 710 group = 1; 711 err = PTR_ERR(handle); 712 goto exit_err; 713 } 714 715 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) { 716 struct buffer_head *bh; 717 718 /* Out of journal space, and can't get more - abort - so sad */ 719 if (handle->h_buffer_credits == 0 && 720 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) && 721 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA))) 722 break; 723 724 bh = sb_getblk(sb, group * bpg + blk_off); 725 if (unlikely(!bh)) { 726 err = -ENOMEM; 727 break; 728 } 729 ext3_debug("update metadata backup %#04lx\n", 730 (unsigned long)bh->b_blocknr); 731 if ((err = ext3_journal_get_write_access(handle, bh))) { 732 brelse(bh); 733 break; 734 } 735 lock_buffer(bh); 736 memcpy(bh->b_data, data, size); 737 if (rest) 738 memset(bh->b_data + size, 0, rest); 739 set_buffer_uptodate(bh); 740 unlock_buffer(bh); 741 err = ext3_journal_dirty_metadata(handle, bh); 742 brelse(bh); 743 if (err) 744 break; 745 } 746 if ((err2 = ext3_journal_stop(handle)) && !err) 747 err = err2; 748 749 /* 750 * Ugh! Need to have e2fsck write the backup copies. It is too 751 * late to revert the resize, we shouldn't fail just because of 752 * the backup copies (they are only needed in case of corruption). 753 * 754 * However, if we got here we have a journal problem too, so we 755 * can't really start a transaction to mark the superblock. 756 * Chicken out and just set the flag on the hope it will be written 757 * to disk, and if not - we will simply wait until next fsck. 758 */ 759exit_err: 760 if (err) { 761 ext3_warning(sb, __func__, 762 "can't update backup for group %d (err %d), " 763 "forcing fsck on next reboot", group, err); 764 sbi->s_mount_state &= ~EXT3_VALID_FS; 765 sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS); 766 mark_buffer_dirty(sbi->s_sbh); 767 } 768} 769 770/* Add group descriptor data to an existing or new group descriptor block. 771 * Ensure we handle all possible error conditions _before_ we start modifying 772 * the filesystem, because we cannot abort the transaction and not have it 773 * write the data to disk. 774 * 775 * If we are on a GDT block boundary, we need to get the reserved GDT block. 776 * Otherwise, we may need to add backup GDT blocks for a sparse group. 777 * 778 * We only need to hold the superblock lock while we are actually adding 779 * in the new group's counts to the superblock. Prior to that we have 780 * not really "added" the group at all. We re-check that we are still 781 * adding in the last group in case things have changed since verifying. 782 */ 783int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input) 784{ 785 struct ext3_sb_info *sbi = EXT3_SB(sb); 786 struct ext3_super_block *es = sbi->s_es; 787 int reserved_gdb = ext3_bg_has_super(sb, input->group) ? 788 le16_to_cpu(es->s_reserved_gdt_blocks) : 0; 789 struct buffer_head *primary = NULL; 790 struct ext3_group_desc *gdp; 791 struct inode *inode = NULL; 792 handle_t *handle; 793 int gdb_off, gdb_num; 794 int err, err2; 795 796 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb); 797 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb); 798 799 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb, 800 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 801 ext3_warning(sb, __func__, 802 "Can't resize non-sparse filesystem further"); 803 return -EPERM; 804 } 805 806 if (le32_to_cpu(es->s_blocks_count) + input->blocks_count < 807 le32_to_cpu(es->s_blocks_count)) { 808 ext3_warning(sb, __func__, "blocks_count overflow\n"); 809 return -EINVAL; 810 } 811 812 if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) < 813 le32_to_cpu(es->s_inodes_count)) { 814 ext3_warning(sb, __func__, "inodes_count overflow\n"); 815 return -EINVAL; 816 } 817 818 if (reserved_gdb || gdb_off == 0) { 819 if (!EXT3_HAS_COMPAT_FEATURE(sb, 820 EXT3_FEATURE_COMPAT_RESIZE_INODE) 821 || !le16_to_cpu(es->s_reserved_gdt_blocks)) { 822 ext3_warning(sb, __func__, 823 "No reserved GDT blocks, can't resize"); 824 return -EPERM; 825 } 826 inode = ext3_iget(sb, EXT3_RESIZE_INO); 827 if (IS_ERR(inode)) { 828 ext3_warning(sb, __func__, 829 "Error opening resize inode"); 830 return PTR_ERR(inode); 831 } 832 } 833 834 if ((err = verify_group_input(sb, input))) 835 goto exit_put; 836 837 if ((err = setup_new_group_blocks(sb, input))) 838 goto exit_put; 839 840 /* 841 * We will always be modifying at least the superblock and a GDT 842 * block. If we are adding a group past the last current GDT block, 843 * we will also modify the inode and the dindirect block. If we 844 * are adding a group with superblock/GDT backups we will also 845 * modify each of the reserved GDT dindirect blocks. 846 */ 847 handle = ext3_journal_start_sb(sb, 848 ext3_bg_has_super(sb, input->group) ? 849 3 + reserved_gdb : 4); 850 if (IS_ERR(handle)) { 851 err = PTR_ERR(handle); 852 goto exit_put; 853 } 854 855 mutex_lock(&sbi->s_resize_lock); 856 if (input->group != sbi->s_groups_count) { 857 ext3_warning(sb, __func__, 858 "multiple resizers run on filesystem!"); 859 err = -EBUSY; 860 goto exit_journal; 861 } 862 863 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh))) 864 goto exit_journal; 865 866 /* 867 * We will only either add reserved group blocks to a backup group 868 * or remove reserved blocks for the first group in a new group block. 869 * Doing both would be mean more complex code, and sane people don't 870 * use non-sparse filesystems anymore. This is already checked above. 871 */ 872 if (gdb_off) { 873 primary = sbi->s_group_desc[gdb_num]; 874 if ((err = ext3_journal_get_write_access(handle, primary))) 875 goto exit_journal; 876 877 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) && 878 (err = reserve_backup_gdb(handle, inode, input))) 879 goto exit_journal; 880 } else if ((err = add_new_gdb(handle, inode, input, &primary))) 881 goto exit_journal; 882 883 /* 884 * OK, now we've set up the new group. Time to make it active. 885 * 886 * We do not lock all allocations via s_resize_lock 887 * so we have to be safe wrt. concurrent accesses the group 888 * data. So we need to be careful to set all of the relevant 889 * group descriptor data etc. *before* we enable the group. 890 * 891 * The key field here is sbi->s_groups_count: as long as 892 * that retains its old value, nobody is going to access the new 893 * group. 894 * 895 * So first we update all the descriptor metadata for the new 896 * group; then we update the total disk blocks count; then we 897 * update the groups count to enable the group; then finally we 898 * update the free space counts so that the system can start 899 * using the new disk blocks. 900 */ 901 902 /* Update group descriptor block for new group */ 903 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off; 904 905 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap); 906 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap); 907 gdp->bg_inode_table = cpu_to_le32(input->inode_table); 908 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count); 909 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb)); 910 911 /* 912 * Make the new blocks and inodes valid next. We do this before 913 * increasing the group count so that once the group is enabled, 914 * all of its blocks and inodes are already valid. 915 * 916 * We always allocate group-by-group, then block-by-block or 917 * inode-by-inode within a group, so enabling these 918 * blocks/inodes before the group is live won't actually let us 919 * allocate the new space yet. 920 */ 921 le32_add_cpu(&es->s_blocks_count, input->blocks_count); 922 le32_add_cpu(&es->s_inodes_count, EXT3_INODES_PER_GROUP(sb)); 923 924 /* 925 * We need to protect s_groups_count against other CPUs seeing 926 * inconsistent state in the superblock. 927 * 928 * The precise rules we use are: 929 * 930 * * Writers of s_groups_count *must* hold s_resize_lock 931 * AND 932 * * Writers must perform a smp_wmb() after updating all dependent 933 * data and before modifying the groups count 934 * 935 * * Readers must hold s_resize_lock over the access 936 * OR 937 * * Readers must perform an smp_rmb() after reading the groups count 938 * and before reading any dependent data. 939 * 940 * NB. These rules can be relaxed when checking the group count 941 * while freeing data, as we can only allocate from a block 942 * group after serialising against the group count, and we can 943 * only then free after serialising in turn against that 944 * allocation. 945 */ 946 smp_wmb(); 947 948 /* Update the global fs size fields */ 949 sbi->s_groups_count++; 950 951 err = ext3_journal_dirty_metadata(handle, primary); 952 if (err) 953 goto exit_journal; 954 955 /* Update the reserved block counts only once the new group is 956 * active. */ 957 le32_add_cpu(&es->s_r_blocks_count, input->reserved_blocks); 958 959 /* Update the free space counts */ 960 percpu_counter_add(&sbi->s_freeblocks_counter, 961 input->free_blocks_count); 962 percpu_counter_add(&sbi->s_freeinodes_counter, 963 EXT3_INODES_PER_GROUP(sb)); 964 965 err = ext3_journal_dirty_metadata(handle, sbi->s_sbh); 966 967exit_journal: 968 mutex_unlock(&sbi->s_resize_lock); 969 if ((err2 = ext3_journal_stop(handle)) && !err) 970 err = err2; 971 if (!err) { 972 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, 973 sizeof(struct ext3_super_block)); 974 update_backups(sb, primary->b_blocknr, primary->b_data, 975 primary->b_size); 976 } 977exit_put: 978 iput(inode); 979 return err; 980} /* ext3_group_add */ 981 982/* Extend the filesystem to the new number of blocks specified. This entry 983 * point is only used to extend the current filesystem to the end of the last 984 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>" 985 * for emergencies (because it has no dependencies on reserved blocks). 986 * 987 * If we _really_ wanted, we could use default values to call ext3_group_add() 988 * allow the "remount" trick to work for arbitrary resizing, assuming enough 989 * GDT blocks are reserved to grow to the desired size. 990 */ 991int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es, 992 ext3_fsblk_t n_blocks_count) 993{ 994 ext3_fsblk_t o_blocks_count; 995 ext3_grpblk_t last; 996 ext3_grpblk_t add; 997 struct buffer_head * bh; 998 handle_t *handle; 999 int err; 1000 unsigned long freed_blocks; 1001 1002 /* We don't need to worry about locking wrt other resizers just 1003 * yet: we're going to revalidate es->s_blocks_count after 1004 * taking the s_resize_lock below. */ 1005 o_blocks_count = le32_to_cpu(es->s_blocks_count); 1006 1007 if (test_opt(sb, DEBUG)) 1008 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK 1009 " up to "E3FSBLK" blocks\n", 1010 o_blocks_count, n_blocks_count); 1011 1012 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count) 1013 return 0; 1014 1015 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { 1016 printk(KERN_ERR "EXT3-fs: filesystem on %s:" 1017 " too large to resize to "E3FSBLK" blocks safely\n", 1018 sb->s_id, n_blocks_count); 1019 if (sizeof(sector_t) < 8) 1020 ext3_warning(sb, __func__, 1021 "CONFIG_LBDAF not enabled\n"); 1022 return -EINVAL; 1023 } 1024 1025 if (n_blocks_count < o_blocks_count) { 1026 ext3_warning(sb, __func__, 1027 "can't shrink FS - resize aborted"); 1028 return -EBUSY; 1029 } 1030 1031 /* Handle the remaining blocks in the last group only. */ 1032 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) % 1033 EXT3_BLOCKS_PER_GROUP(sb); 1034 1035 if (last == 0) { 1036 ext3_warning(sb, __func__, 1037 "need to use ext2online to resize further"); 1038 return -EPERM; 1039 } 1040 1041 add = EXT3_BLOCKS_PER_GROUP(sb) - last; 1042 1043 if (o_blocks_count + add < o_blocks_count) { 1044 ext3_warning(sb, __func__, "blocks_count overflow"); 1045 return -EINVAL; 1046 } 1047 1048 if (o_blocks_count + add > n_blocks_count) 1049 add = n_blocks_count - o_blocks_count; 1050 1051 if (o_blocks_count + add < n_blocks_count) 1052 ext3_warning(sb, __func__, 1053 "will only finish group ("E3FSBLK 1054 " blocks, %u new)", 1055 o_blocks_count + add, add); 1056 1057 /* See if the device is actually as big as what was requested */ 1058 bh = sb_bread(sb, o_blocks_count + add -1); 1059 if (!bh) { 1060 ext3_warning(sb, __func__, 1061 "can't read last block, resize aborted"); 1062 return -ENOSPC; 1063 } 1064 brelse(bh); 1065 1066 /* We will update the superblock, one block bitmap, and 1067 * one group descriptor via ext3_free_blocks(). 1068 */ 1069 handle = ext3_journal_start_sb(sb, 3); 1070 if (IS_ERR(handle)) { 1071 err = PTR_ERR(handle); 1072 ext3_warning(sb, __func__, "error %d on journal start",err); 1073 goto exit_put; 1074 } 1075 1076 mutex_lock(&EXT3_SB(sb)->s_resize_lock); 1077 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) { 1078 ext3_warning(sb, __func__, 1079 "multiple resizers run on filesystem!"); 1080 mutex_unlock(&EXT3_SB(sb)->s_resize_lock); 1081 ext3_journal_stop(handle); 1082 err = -EBUSY; 1083 goto exit_put; 1084 } 1085 1086 if ((err = ext3_journal_get_write_access(handle, 1087 EXT3_SB(sb)->s_sbh))) { 1088 ext3_warning(sb, __func__, 1089 "error %d on journal write access", err); 1090 mutex_unlock(&EXT3_SB(sb)->s_resize_lock); 1091 ext3_journal_stop(handle); 1092 goto exit_put; 1093 } 1094 es->s_blocks_count = cpu_to_le32(o_blocks_count + add); 1095 err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh); 1096 mutex_unlock(&EXT3_SB(sb)->s_resize_lock); 1097 if (err) { 1098 ext3_warning(sb, __func__, 1099 "error %d on journal dirty metadata", err); 1100 ext3_journal_stop(handle); 1101 goto exit_put; 1102 } 1103 ext3_debug("freeing blocks "E3FSBLK" through "E3FSBLK"\n", 1104 o_blocks_count, o_blocks_count + add); 1105 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks); 1106 ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", 1107 o_blocks_count, o_blocks_count + add); 1108 if ((err = ext3_journal_stop(handle))) 1109 goto exit_put; 1110 if (test_opt(sb, DEBUG)) 1111 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n", 1112 le32_to_cpu(es->s_blocks_count)); 1113 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es, 1114 sizeof(struct ext3_super_block)); 1115exit_put: 1116 return err; 1117} /* ext3_group_extend */ 1118