1 /* 2 * linux/fs/ext4/resize.c 3 * 4 * Support for resizing an ext4 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 EXT4FS_DEBUG 13 14 #include <linux/smp_lock.h> 15 #include <linux/ext4_jbd2.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 ext4_new_group_data *input) 26 { 27 struct ext4_sb_info *sbi = EXT4_SB(sb); 28 struct ext4_super_block *es = sbi->s_es; 29 ext4_fsblk_t start = ext4_blocks_count(es); 30 ext4_fsblk_t end = start + input->blocks_count; 31 unsigned group = input->group; 32 ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group; 33 unsigned overhead = ext4_bg_has_super(sb, group) ? 34 (1 + ext4_bg_num_gdb(sb, group) + 35 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0; 36 ext4_fsblk_t metaend = start + overhead; 37 struct buffer_head *bh = NULL; 38 ext4_grpblk_t free_blocks_count, offset; 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 "EXT4-fs: adding %s group %u: %u blocks " 46 "(%d free, %u reserved)\n", 47 ext4_bg_has_super(sb, input->group) ? "normal" : 48 "no-super", input->group, input->blocks_count, 49 free_blocks_count, input->reserved_blocks); 50 51 ext4_get_group_no_and_offset(sb, start, NULL, &offset); 52 if (group != sbi->s_groups_count) 53 ext4_warning(sb, __FUNCTION__, 54 "Cannot add at group %u (only %lu groups)", 55 input->group, sbi->s_groups_count); 56 else if (offset != 0) 57 ext4_warning(sb, __FUNCTION__, "Last group not full"); 58 else if (input->reserved_blocks > input->blocks_count / 5) 59 ext4_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)", 60 input->reserved_blocks); 61 else if (free_blocks_count < 0) 62 ext4_warning(sb, __FUNCTION__, "Bad blocks count %u", 63 input->blocks_count); 64 else if (!(bh = sb_bread(sb, end - 1))) 65 ext4_warning(sb, __FUNCTION__, 66 "Cannot read last block (%llu)", 67 end - 1); 68 else if (outside(input->block_bitmap, start, end)) 69 ext4_warning(sb, __FUNCTION__, 70 "Block bitmap not in group (block %llu)", 71 (unsigned long long)input->block_bitmap); 72 else if (outside(input->inode_bitmap, start, end)) 73 ext4_warning(sb, __FUNCTION__, 74 "Inode bitmap not in group (block %llu)", 75 (unsigned long long)input->inode_bitmap); 76 else if (outside(input->inode_table, start, end) || 77 outside(itend - 1, start, end)) 78 ext4_warning(sb, __FUNCTION__, 79 "Inode table not in group (blocks %llu-%llu)", 80 (unsigned long long)input->inode_table, itend - 1); 81 else if (input->inode_bitmap == input->block_bitmap) 82 ext4_warning(sb, __FUNCTION__, 83 "Block bitmap same as inode bitmap (%llu)", 84 (unsigned long long)input->block_bitmap); 85 else if (inside(input->block_bitmap, input->inode_table, itend)) 86 ext4_warning(sb, __FUNCTION__, 87 "Block bitmap (%llu) in inode table (%llu-%llu)", 88 (unsigned long long)input->block_bitmap, 89 (unsigned long long)input->inode_table, itend - 1); 90 else if (inside(input->inode_bitmap, input->inode_table, itend)) 91 ext4_warning(sb, __FUNCTION__, 92 "Inode bitmap (%llu) in inode table (%llu-%llu)", 93 (unsigned long long)input->inode_bitmap, 94 (unsigned long long)input->inode_table, itend - 1); 95 else if (inside(input->block_bitmap, start, metaend)) 96 ext4_warning(sb, __FUNCTION__, 97 "Block bitmap (%llu) in GDT table" 98 " (%llu-%llu)", 99 (unsigned long long)input->block_bitmap, 100 start, metaend - 1); 101 else if (inside(input->inode_bitmap, start, metaend)) 102 ext4_warning(sb, __FUNCTION__, 103 "Inode bitmap (%llu) in GDT table" 104 " (%llu-%llu)", 105 (unsigned long long)input->inode_bitmap, 106 start, metaend - 1); 107 else if (inside(input->inode_table, start, metaend) || 108 inside(itend - 1, start, metaend)) 109 ext4_warning(sb, __FUNCTION__, 110 "Inode table (%llu-%llu) overlaps" 111 "GDT table (%llu-%llu)", 112 (unsigned long long)input->inode_table, 113 itend - 1, start, metaend - 1); 114 else 115 err = 0; 116 brelse(bh); 117 118 return err; 119 } 120 121 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, 122 ext4_fsblk_t blk) 123 { 124 struct buffer_head *bh; 125 int err; 126 127 bh = sb_getblk(sb, blk); 128 if (!bh) 129 return ERR_PTR(-EIO); 130 if ((err = ext4_journal_get_write_access(handle, bh))) { 131 brelse(bh); 132 bh = ERR_PTR(err); 133 } else { 134 lock_buffer(bh); 135 memset(bh->b_data, 0, sb->s_blocksize); 136 set_buffer_uptodate(bh); 137 unlock_buffer(bh); 138 } 139 140 return bh; 141 } 142 143 /* 144 * To avoid calling the atomic setbit hundreds or thousands of times, we only 145 * need to use it within a single byte (to ensure we get endianness right). 146 * We can use memset for the rest of the bitmap as there are no other users. 147 */ 148 static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap) 149 { 150 int i; 151 152 if (start_bit >= end_bit) 153 return; 154 155 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit); 156 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++) 157 ext4_set_bit(i, bitmap); 158 if (i < end_bit) 159 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3); 160 } 161 162 /* 163 * Set up the block and inode bitmaps, and the inode table for the new group. 164 * This doesn't need to be part of the main transaction, since we are only 165 * changing blocks outside the actual filesystem. We still do journaling to 166 * ensure the recovery is correct in case of a failure just after resize. 167 * If any part of this fails, we simply abort the resize. 168 */ 169 static int setup_new_group_blocks(struct super_block *sb, 170 struct ext4_new_group_data *input) 171 { 172 struct ext4_sb_info *sbi = EXT4_SB(sb); 173 ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group); 174 int reserved_gdb = ext4_bg_has_super(sb, input->group) ? 175 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0; 176 unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group); 177 struct buffer_head *bh; 178 handle_t *handle; 179 ext4_fsblk_t block; 180 ext4_grpblk_t bit; 181 int i; 182 int err = 0, err2; 183 184 handle = ext4_journal_start_sb(sb, reserved_gdb + gdblocks + 185 2 + sbi->s_itb_per_group); 186 if (IS_ERR(handle)) 187 return PTR_ERR(handle); 188 189 lock_super(sb); 190 if (input->group != sbi->s_groups_count) { 191 err = -EBUSY; 192 goto exit_journal; 193 } 194 195 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) { 196 err = PTR_ERR(bh); 197 goto exit_journal; 198 } 199 200 if (ext4_bg_has_super(sb, input->group)) { 201 ext4_debug("mark backup superblock %#04lx (+0)\n", start); 202 ext4_set_bit(0, bh->b_data); 203 } 204 205 /* Copy all of the GDT blocks into the backup in this group */ 206 for (i = 0, bit = 1, block = start + 1; 207 i < gdblocks; i++, block++, bit++) { 208 struct buffer_head *gdb; 209 210 ext4_debug("update backup group %#04lx (+%d)\n", block, bit); 211 212 gdb = sb_getblk(sb, block); 213 if (!gdb) { 214 err = -EIO; 215 goto exit_bh; 216 } 217 if ((err = ext4_journal_get_write_access(handle, gdb))) { 218 brelse(gdb); 219 goto exit_bh; 220 } 221 lock_buffer(bh); 222 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size); 223 set_buffer_uptodate(gdb); 224 unlock_buffer(bh); 225 ext4_journal_dirty_metadata(handle, gdb); 226 ext4_set_bit(bit, bh->b_data); 227 brelse(gdb); 228 } 229 230 /* Zero out all of the reserved backup group descriptor table blocks */ 231 for (i = 0, bit = gdblocks + 1, block = start + bit; 232 i < reserved_gdb; i++, block++, bit++) { 233 struct buffer_head *gdb; 234 235 ext4_debug("clear reserved block %#04lx (+%d)\n", block, bit); 236 237 if (IS_ERR(gdb = bclean(handle, sb, block))) { 238 err = PTR_ERR(bh); 239 goto exit_bh; 240 } 241 ext4_journal_dirty_metadata(handle, gdb); 242 ext4_set_bit(bit, bh->b_data); 243 brelse(gdb); 244 } 245 ext4_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap, 246 input->block_bitmap - start); 247 ext4_set_bit(input->block_bitmap - start, bh->b_data); 248 ext4_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap, 249 input->inode_bitmap - start); 250 ext4_set_bit(input->inode_bitmap - start, bh->b_data); 251 252 /* Zero out all of the inode table blocks */ 253 for (i = 0, block = input->inode_table, bit = block - start; 254 i < sbi->s_itb_per_group; i++, bit++, block++) { 255 struct buffer_head *it; 256 257 ext4_debug("clear inode block %#04lx (+%d)\n", block, bit); 258 if (IS_ERR(it = bclean(handle, sb, block))) { 259 err = PTR_ERR(it); 260 goto exit_bh; 261 } 262 ext4_journal_dirty_metadata(handle, it); 263 brelse(it); 264 ext4_set_bit(bit, bh->b_data); 265 } 266 mark_bitmap_end(input->blocks_count, EXT4_BLOCKS_PER_GROUP(sb), 267 bh->b_data); 268 ext4_journal_dirty_metadata(handle, bh); 269 brelse(bh); 270 271 /* Mark unused entries in inode bitmap used */ 272 ext4_debug("clear inode bitmap %#04x (+%ld)\n", 273 input->inode_bitmap, input->inode_bitmap - start); 274 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) { 275 err = PTR_ERR(bh); 276 goto exit_journal; 277 } 278 279 mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb), 280 bh->b_data); 281 ext4_journal_dirty_metadata(handle, bh); 282 exit_bh: 283 brelse(bh); 284 285 exit_journal: 286 unlock_super(sb); 287 if ((err2 = ext4_journal_stop(handle)) && !err) 288 err = err2; 289 290 return err; 291 } 292 293 294 /* 295 * Iterate through the groups which hold BACKUP superblock/GDT copies in an 296 * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before 297 * calling this for the first time. In a sparse filesystem it will be the 298 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... 299 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... 300 */ 301 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three, 302 unsigned *five, unsigned *seven) 303 { 304 unsigned *min = three; 305 int mult = 3; 306 unsigned ret; 307 308 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, 309 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 310 ret = *min; 311 *min += 1; 312 return ret; 313 } 314 315 if (*five < *min) { 316 min = five; 317 mult = 5; 318 } 319 if (*seven < *min) { 320 min = seven; 321 mult = 7; 322 } 323 324 ret = *min; 325 *min *= mult; 326 327 return ret; 328 } 329 330 /* 331 * Check that all of the backup GDT blocks are held in the primary GDT block. 332 * It is assumed that they are stored in group order. Returns the number of 333 * groups in current filesystem that have BACKUPS, or -ve error code. 334 */ 335 static int verify_reserved_gdb(struct super_block *sb, 336 struct buffer_head *primary) 337 { 338 const ext4_fsblk_t blk = primary->b_blocknr; 339 const unsigned long end = EXT4_SB(sb)->s_groups_count; 340 unsigned three = 1; 341 unsigned five = 5; 342 unsigned seven = 7; 343 unsigned grp; 344 __le32 *p = (__le32 *)primary->b_data; 345 int gdbackups = 0; 346 347 while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) { 348 if (le32_to_cpu(*p++) != 349 grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){ 350 ext4_warning(sb, __FUNCTION__, 351 "reserved GDT %llu" 352 " missing grp %d (%llu)", 353 blk, grp, 354 grp * 355 (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) + 356 blk); 357 return -EINVAL; 358 } 359 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb)) 360 return -EFBIG; 361 } 362 363 return gdbackups; 364 } 365 366 /* 367 * Called when we need to bring a reserved group descriptor table block into 368 * use from the resize inode. The primary copy of the new GDT block currently 369 * is an indirect block (under the double indirect block in the resize inode). 370 * The new backup GDT blocks will be stored as leaf blocks in this indirect 371 * block, in group order. Even though we know all the block numbers we need, 372 * we check to ensure that the resize inode has actually reserved these blocks. 373 * 374 * Don't need to update the block bitmaps because the blocks are still in use. 375 * 376 * We get all of the error cases out of the way, so that we are sure to not 377 * fail once we start modifying the data on disk, because JBD has no rollback. 378 */ 379 static int add_new_gdb(handle_t *handle, struct inode *inode, 380 struct ext4_new_group_data *input, 381 struct buffer_head **primary) 382 { 383 struct super_block *sb = inode->i_sb; 384 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 385 unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); 386 ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num; 387 struct buffer_head **o_group_desc, **n_group_desc; 388 struct buffer_head *dind; 389 int gdbackups; 390 struct ext4_iloc iloc; 391 __le32 *data; 392 int err; 393 394 if (test_opt(sb, DEBUG)) 395 printk(KERN_DEBUG 396 "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n", 397 gdb_num); 398 399 /* 400 * If we are not using the primary superblock/GDT copy don't resize, 401 * because the user tools have no way of handling this. Probably a 402 * bad time to do it anyways. 403 */ 404 if (EXT4_SB(sb)->s_sbh->b_blocknr != 405 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { 406 ext4_warning(sb, __FUNCTION__, 407 "won't resize using backup superblock at %llu", 408 (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); 409 return -EPERM; 410 } 411 412 *primary = sb_bread(sb, gdblock); 413 if (!*primary) 414 return -EIO; 415 416 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) { 417 err = gdbackups; 418 goto exit_bh; 419 } 420 421 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; 422 dind = sb_bread(sb, le32_to_cpu(*data)); 423 if (!dind) { 424 err = -EIO; 425 goto exit_bh; 426 } 427 428 data = (__le32 *)dind->b_data; 429 if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) { 430 ext4_warning(sb, __FUNCTION__, 431 "new group %u GDT block %llu not reserved", 432 input->group, gdblock); 433 err = -EINVAL; 434 goto exit_dind; 435 } 436 437 if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh))) 438 goto exit_dind; 439 440 if ((err = ext4_journal_get_write_access(handle, *primary))) 441 goto exit_sbh; 442 443 if ((err = ext4_journal_get_write_access(handle, dind))) 444 goto exit_primary; 445 446 /* ext4_reserve_inode_write() gets a reference on the iloc */ 447 if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) 448 goto exit_dindj; 449 450 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *), 451 GFP_KERNEL); 452 if (!n_group_desc) { 453 err = -ENOMEM; 454 ext4_warning (sb, __FUNCTION__, 455 "not enough memory for %lu groups", gdb_num + 1); 456 goto exit_inode; 457 } 458 459 /* 460 * Finally, we have all of the possible failures behind us... 461 * 462 * Remove new GDT block from inode double-indirect block and clear out 463 * the new GDT block for use (which also "frees" the backup GDT blocks 464 * from the reserved inode). We don't need to change the bitmaps for 465 * these blocks, because they are marked as in-use from being in the 466 * reserved inode, and will become GDT blocks (primary and backup). 467 */ 468 data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0; 469 ext4_journal_dirty_metadata(handle, dind); 470 brelse(dind); 471 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9; 472 ext4_mark_iloc_dirty(handle, inode, &iloc); 473 memset((*primary)->b_data, 0, sb->s_blocksize); 474 ext4_journal_dirty_metadata(handle, *primary); 475 476 o_group_desc = EXT4_SB(sb)->s_group_desc; 477 memcpy(n_group_desc, o_group_desc, 478 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); 479 n_group_desc[gdb_num] = *primary; 480 EXT4_SB(sb)->s_group_desc = n_group_desc; 481 EXT4_SB(sb)->s_gdb_count++; 482 kfree(o_group_desc); 483 484 es->s_reserved_gdt_blocks = 485 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1); 486 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); 487 488 return 0; 489 490 exit_inode: 491 //ext4_journal_release_buffer(handle, iloc.bh); 492 brelse(iloc.bh); 493 exit_dindj: 494 //ext4_journal_release_buffer(handle, dind); 495 exit_primary: 496 //ext4_journal_release_buffer(handle, *primary); 497 exit_sbh: 498 //ext4_journal_release_buffer(handle, *primary); 499 exit_dind: 500 brelse(dind); 501 exit_bh: 502 brelse(*primary); 503 504 ext4_debug("leaving with error %d\n", err); 505 return err; 506 } 507 508 /* 509 * Called when we are adding a new group which has a backup copy of each of 510 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks. 511 * We need to add these reserved backup GDT blocks to the resize inode, so 512 * that they are kept for future resizing and not allocated to files. 513 * 514 * Each reserved backup GDT block will go into a different indirect block. 515 * The indirect blocks are actually the primary reserved GDT blocks, 516 * so we know in advance what their block numbers are. We only get the 517 * double-indirect block to verify it is pointing to the primary reserved 518 * GDT blocks so we don't overwrite a data block by accident. The reserved 519 * backup GDT blocks are stored in their reserved primary GDT block. 520 */ 521 static int reserve_backup_gdb(handle_t *handle, struct inode *inode, 522 struct ext4_new_group_data *input) 523 { 524 struct super_block *sb = inode->i_sb; 525 int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks); 526 struct buffer_head **primary; 527 struct buffer_head *dind; 528 struct ext4_iloc iloc; 529 ext4_fsblk_t blk; 530 __le32 *data, *end; 531 int gdbackups = 0; 532 int res, i; 533 int err; 534 535 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL); 536 if (!primary) 537 return -ENOMEM; 538 539 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; 540 dind = sb_bread(sb, le32_to_cpu(*data)); 541 if (!dind) { 542 err = -EIO; 543 goto exit_free; 544 } 545 546 blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count; 547 data = (__le32 *)dind->b_data + EXT4_SB(sb)->s_gdb_count; 548 end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb); 549 550 /* Get each reserved primary GDT block and verify it holds backups */ 551 for (res = 0; res < reserved_gdb; res++, blk++) { 552 if (le32_to_cpu(*data) != blk) { 553 ext4_warning(sb, __FUNCTION__, 554 "reserved block %llu" 555 " not at offset %ld", 556 blk, 557 (long)(data - (__le32 *)dind->b_data)); 558 err = -EINVAL; 559 goto exit_bh; 560 } 561 primary[res] = sb_bread(sb, blk); 562 if (!primary[res]) { 563 err = -EIO; 564 goto exit_bh; 565 } 566 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) { 567 brelse(primary[res]); 568 err = gdbackups; 569 goto exit_bh; 570 } 571 if (++data >= end) 572 data = (__le32 *)dind->b_data; 573 } 574 575 for (i = 0; i < reserved_gdb; i++) { 576 if ((err = ext4_journal_get_write_access(handle, primary[i]))) { 577 /* 578 int j; 579 for (j = 0; j < i; j++) 580 ext4_journal_release_buffer(handle, primary[j]); 581 */ 582 goto exit_bh; 583 } 584 } 585 586 if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) 587 goto exit_bh; 588 589 /* 590 * Finally we can add each of the reserved backup GDT blocks from 591 * the new group to its reserved primary GDT block. 592 */ 593 blk = input->group * EXT4_BLOCKS_PER_GROUP(sb); 594 for (i = 0; i < reserved_gdb; i++) { 595 int err2; 596 data = (__le32 *)primary[i]->b_data; 597 /* printk("reserving backup %lu[%u] = %lu\n", 598 primary[i]->b_blocknr, gdbackups, 599 blk + primary[i]->b_blocknr); */ 600 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr); 601 err2 = ext4_journal_dirty_metadata(handle, primary[i]); 602 if (!err) 603 err = err2; 604 } 605 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9; 606 ext4_mark_iloc_dirty(handle, inode, &iloc); 607 608 exit_bh: 609 while (--res >= 0) 610 brelse(primary[res]); 611 brelse(dind); 612 613 exit_free: 614 kfree(primary); 615 616 return err; 617 } 618 619 /* 620 * Update the backup copies of the ext4 metadata. These don't need to be part 621 * of the main resize transaction, because e2fsck will re-write them if there 622 * is a problem (basically only OOM will cause a problem). However, we 623 * _should_ update the backups if possible, in case the primary gets trashed 624 * for some reason and we need to run e2fsck from a backup superblock. The 625 * important part is that the new block and inode counts are in the backup 626 * superblocks, and the location of the new group metadata in the GDT backups. 627 * 628 * We do not need lock_super() for this, because these blocks are not 629 * otherwise touched by the filesystem code when it is mounted. We don't 630 * need to worry about last changing from sbi->s_groups_count, because the 631 * worst that can happen is that we do not copy the full number of backups 632 * at this time. The resize which changed s_groups_count will backup again. 633 */ 634 static void update_backups(struct super_block *sb, 635 int blk_off, char *data, int size) 636 { 637 struct ext4_sb_info *sbi = EXT4_SB(sb); 638 const unsigned long last = sbi->s_groups_count; 639 const int bpg = EXT4_BLOCKS_PER_GROUP(sb); 640 unsigned three = 1; 641 unsigned five = 5; 642 unsigned seven = 7; 643 unsigned group; 644 int rest = sb->s_blocksize - size; 645 handle_t *handle; 646 int err = 0, err2; 647 648 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA); 649 if (IS_ERR(handle)) { 650 group = 1; 651 err = PTR_ERR(handle); 652 goto exit_err; 653 } 654 655 while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) { 656 struct buffer_head *bh; 657 658 /* Out of journal space, and can't get more - abort - so sad */ 659 if (handle->h_buffer_credits == 0 && 660 ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) && 661 (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA))) 662 break; 663 664 bh = sb_getblk(sb, group * bpg + blk_off); 665 if (!bh) { 666 err = -EIO; 667 break; 668 } 669 ext4_debug("update metadata backup %#04lx\n", 670 (unsigned long)bh->b_blocknr); 671 if ((err = ext4_journal_get_write_access(handle, bh))) 672 break; 673 lock_buffer(bh); 674 memcpy(bh->b_data, data, size); 675 if (rest) 676 memset(bh->b_data + size, 0, rest); 677 set_buffer_uptodate(bh); 678 unlock_buffer(bh); 679 ext4_journal_dirty_metadata(handle, bh); 680 brelse(bh); 681 } 682 if ((err2 = ext4_journal_stop(handle)) && !err) 683 err = err2; 684 685 /* 686 * Ugh! Need to have e2fsck write the backup copies. It is too 687 * late to revert the resize, we shouldn't fail just because of 688 * the backup copies (they are only needed in case of corruption). 689 * 690 * However, if we got here we have a journal problem too, so we 691 * can't really start a transaction to mark the superblock. 692 * Chicken out and just set the flag on the hope it will be written 693 * to disk, and if not - we will simply wait until next fsck. 694 */ 695 exit_err: 696 if (err) { 697 ext4_warning(sb, __FUNCTION__, 698 "can't update backup for group %d (err %d), " 699 "forcing fsck on next reboot", group, err); 700 sbi->s_mount_state &= ~EXT4_VALID_FS; 701 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS); 702 mark_buffer_dirty(sbi->s_sbh); 703 } 704 } 705 706 /* Add group descriptor data to an existing or new group descriptor block. 707 * Ensure we handle all possible error conditions _before_ we start modifying 708 * the filesystem, because we cannot abort the transaction and not have it 709 * write the data to disk. 710 * 711 * If we are on a GDT block boundary, we need to get the reserved GDT block. 712 * Otherwise, we may need to add backup GDT blocks for a sparse group. 713 * 714 * We only need to hold the superblock lock while we are actually adding 715 * in the new group's counts to the superblock. Prior to that we have 716 * not really "added" the group at all. We re-check that we are still 717 * adding in the last group in case things have changed since verifying. 718 */ 719 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) 720 { 721 struct ext4_sb_info *sbi = EXT4_SB(sb); 722 struct ext4_super_block *es = sbi->s_es; 723 int reserved_gdb = ext4_bg_has_super(sb, input->group) ? 724 le16_to_cpu(es->s_reserved_gdt_blocks) : 0; 725 struct buffer_head *primary = NULL; 726 struct ext4_group_desc *gdp; 727 struct inode *inode = NULL; 728 handle_t *handle; 729 int gdb_off, gdb_num; 730 int err, err2; 731 732 gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); 733 gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb); 734 735 if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb, 736 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 737 ext4_warning(sb, __FUNCTION__, 738 "Can't resize non-sparse filesystem further"); 739 return -EPERM; 740 } 741 742 if (ext4_blocks_count(es) + input->blocks_count < 743 ext4_blocks_count(es)) { 744 ext4_warning(sb, __FUNCTION__, "blocks_count overflow\n"); 745 return -EINVAL; 746 } 747 748 if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) < 749 le32_to_cpu(es->s_inodes_count)) { 750 ext4_warning(sb, __FUNCTION__, "inodes_count overflow\n"); 751 return -EINVAL; 752 } 753 754 if (reserved_gdb || gdb_off == 0) { 755 if (!EXT4_HAS_COMPAT_FEATURE(sb, 756 EXT4_FEATURE_COMPAT_RESIZE_INODE)){ 757 ext4_warning(sb, __FUNCTION__, 758 "No reserved GDT blocks, can't resize"); 759 return -EPERM; 760 } 761 inode = iget(sb, EXT4_RESIZE_INO); 762 if (!inode || is_bad_inode(inode)) { 763 ext4_warning(sb, __FUNCTION__, 764 "Error opening resize inode"); 765 iput(inode); 766 return -ENOENT; 767 } 768 } 769 770 if ((err = verify_group_input(sb, input))) 771 goto exit_put; 772 773 if ((err = setup_new_group_blocks(sb, input))) 774 goto exit_put; 775 776 /* 777 * We will always be modifying at least the superblock and a GDT 778 * block. If we are adding a group past the last current GDT block, 779 * we will also modify the inode and the dindirect block. If we 780 * are adding a group with superblock/GDT backups we will also 781 * modify each of the reserved GDT dindirect blocks. 782 */ 783 handle = ext4_journal_start_sb(sb, 784 ext4_bg_has_super(sb, input->group) ? 785 3 + reserved_gdb : 4); 786 if (IS_ERR(handle)) { 787 err = PTR_ERR(handle); 788 goto exit_put; 789 } 790 791 lock_super(sb); 792 if (input->group != sbi->s_groups_count) { 793 ext4_warning(sb, __FUNCTION__, 794 "multiple resizers run on filesystem!"); 795 err = -EBUSY; 796 goto exit_journal; 797 } 798 799 if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh))) 800 goto exit_journal; 801 802 /* 803 * We will only either add reserved group blocks to a backup group 804 * or remove reserved blocks for the first group in a new group block. 805 * Doing both would be mean more complex code, and sane people don't 806 * use non-sparse filesystems anymore. This is already checked above. 807 */ 808 if (gdb_off) { 809 primary = sbi->s_group_desc[gdb_num]; 810 if ((err = ext4_journal_get_write_access(handle, primary))) 811 goto exit_journal; 812 813 if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) && 814 (err = reserve_backup_gdb(handle, inode, input))) 815 goto exit_journal; 816 } else if ((err = add_new_gdb(handle, inode, input, &primary))) 817 goto exit_journal; 818 819 /* 820 * OK, now we've set up the new group. Time to make it active. 821 * 822 * Current kernels don't lock all allocations via lock_super(), 823 * so we have to be safe wrt. concurrent accesses the group 824 * data. So we need to be careful to set all of the relevant 825 * group descriptor data etc. *before* we enable the group. 826 * 827 * The key field here is sbi->s_groups_count: as long as 828 * that retains its old value, nobody is going to access the new 829 * group. 830 * 831 * So first we update all the descriptor metadata for the new 832 * group; then we update the total disk blocks count; then we 833 * update the groups count to enable the group; then finally we 834 * update the free space counts so that the system can start 835 * using the new disk blocks. 836 */ 837 838 /* Update group descriptor block for new group */ 839 gdp = (struct ext4_group_desc *)primary->b_data + gdb_off; 840 841 ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */ 842 ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */ 843 ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */ 844 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count); 845 gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb)); 846 847 /* 848 * Make the new blocks and inodes valid next. We do this before 849 * increasing the group count so that once the group is enabled, 850 * all of its blocks and inodes are already valid. 851 * 852 * We always allocate group-by-group, then block-by-block or 853 * inode-by-inode within a group, so enabling these 854 * blocks/inodes before the group is live won't actually let us 855 * allocate the new space yet. 856 */ 857 ext4_blocks_count_set(es, ext4_blocks_count(es) + 858 input->blocks_count); 859 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) + 860 EXT4_INODES_PER_GROUP(sb)); 861 862 /* 863 * We need to protect s_groups_count against other CPUs seeing 864 * inconsistent state in the superblock. 865 * 866 * The precise rules we use are: 867 * 868 * * Writers of s_groups_count *must* hold lock_super 869 * AND 870 * * Writers must perform a smp_wmb() after updating all dependent 871 * data and before modifying the groups count 872 * 873 * * Readers must hold lock_super() over the access 874 * OR 875 * * Readers must perform an smp_rmb() after reading the groups count 876 * and before reading any dependent data. 877 * 878 * NB. These rules can be relaxed when checking the group count 879 * while freeing data, as we can only allocate from a block 880 * group after serialising against the group count, and we can 881 * only then free after serialising in turn against that 882 * allocation. 883 */ 884 smp_wmb(); 885 886 /* Update the global fs size fields */ 887 sbi->s_groups_count++; 888 889 ext4_journal_dirty_metadata(handle, primary); 890 891 /* Update the reserved block counts only once the new group is 892 * active. */ 893 ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) + 894 input->reserved_blocks); 895 896 /* Update the free space counts */ 897 percpu_counter_mod(&sbi->s_freeblocks_counter, 898 input->free_blocks_count); 899 percpu_counter_mod(&sbi->s_freeinodes_counter, 900 EXT4_INODES_PER_GROUP(sb)); 901 902 ext4_journal_dirty_metadata(handle, sbi->s_sbh); 903 sb->s_dirt = 1; 904 905 exit_journal: 906 unlock_super(sb); 907 if ((err2 = ext4_journal_stop(handle)) && !err) 908 err = err2; 909 if (!err) { 910 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, 911 sizeof(struct ext4_super_block)); 912 update_backups(sb, primary->b_blocknr, primary->b_data, 913 primary->b_size); 914 } 915 exit_put: 916 iput(inode); 917 return err; 918 } /* ext4_group_add */ 919 920 /* Extend the filesystem to the new number of blocks specified. This entry 921 * point is only used to extend the current filesystem to the end of the last 922 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>" 923 * for emergencies (because it has no dependencies on reserved blocks). 924 * 925 * If we _really_ wanted, we could use default values to call ext4_group_add() 926 * allow the "remount" trick to work for arbitrary resizing, assuming enough 927 * GDT blocks are reserved to grow to the desired size. 928 */ 929 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es, 930 ext4_fsblk_t n_blocks_count) 931 { 932 ext4_fsblk_t o_blocks_count; 933 unsigned long o_groups_count; 934 ext4_grpblk_t last; 935 ext4_grpblk_t add; 936 struct buffer_head * bh; 937 handle_t *handle; 938 int err; 939 unsigned long freed_blocks; 940 941 /* We don't need to worry about locking wrt other resizers just 942 * yet: we're going to revalidate es->s_blocks_count after 943 * taking lock_super() below. */ 944 o_blocks_count = ext4_blocks_count(es); 945 o_groups_count = EXT4_SB(sb)->s_groups_count; 946 947 if (test_opt(sb, DEBUG)) 948 printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n", 949 o_blocks_count, n_blocks_count); 950 951 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count) 952 return 0; 953 954 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { 955 printk(KERN_ERR "EXT4-fs: filesystem on %s:" 956 " too large to resize to %llu blocks safely\n", 957 sb->s_id, n_blocks_count); 958 if (sizeof(sector_t) < 8) 959 ext4_warning(sb, __FUNCTION__, 960 "CONFIG_LBD not enabled\n"); 961 return -EINVAL; 962 } 963 964 if (n_blocks_count < o_blocks_count) { 965 ext4_warning(sb, __FUNCTION__, 966 "can't shrink FS - resize aborted"); 967 return -EBUSY; 968 } 969 970 /* Handle the remaining blocks in the last group only. */ 971 ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last); 972 973 if (last == 0) { 974 ext4_warning(sb, __FUNCTION__, 975 "need to use ext2online to resize further"); 976 return -EPERM; 977 } 978 979 add = EXT4_BLOCKS_PER_GROUP(sb) - last; 980 981 if (o_blocks_count + add < o_blocks_count) { 982 ext4_warning(sb, __FUNCTION__, "blocks_count overflow"); 983 return -EINVAL; 984 } 985 986 if (o_blocks_count + add > n_blocks_count) 987 add = n_blocks_count - o_blocks_count; 988 989 if (o_blocks_count + add < n_blocks_count) 990 ext4_warning(sb, __FUNCTION__, 991 "will only finish group (%llu" 992 " blocks, %u new)", 993 o_blocks_count + add, add); 994 995 /* See if the device is actually as big as what was requested */ 996 bh = sb_bread(sb, o_blocks_count + add -1); 997 if (!bh) { 998 ext4_warning(sb, __FUNCTION__, 999 "can't read last block, resize aborted"); 1000 return -ENOSPC; 1001 } 1002 brelse(bh); 1003 1004 /* We will update the superblock, one block bitmap, and 1005 * one group descriptor via ext4_free_blocks(). 1006 */ 1007 handle = ext4_journal_start_sb(sb, 3); 1008 if (IS_ERR(handle)) { 1009 err = PTR_ERR(handle); 1010 ext4_warning(sb, __FUNCTION__, "error %d on journal start",err); 1011 goto exit_put; 1012 } 1013 1014 lock_super(sb); 1015 if (o_blocks_count != ext4_blocks_count(es)) { 1016 ext4_warning(sb, __FUNCTION__, 1017 "multiple resizers run on filesystem!"); 1018 unlock_super(sb); 1019 err = -EBUSY; 1020 goto exit_put; 1021 } 1022 1023 if ((err = ext4_journal_get_write_access(handle, 1024 EXT4_SB(sb)->s_sbh))) { 1025 ext4_warning(sb, __FUNCTION__, 1026 "error %d on journal write access", err); 1027 unlock_super(sb); 1028 ext4_journal_stop(handle); 1029 goto exit_put; 1030 } 1031 ext4_blocks_count_set(es, o_blocks_count + add); 1032 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); 1033 sb->s_dirt = 1; 1034 unlock_super(sb); 1035 ext4_debug("freeing blocks %lu through %llu\n", o_blocks_count, 1036 o_blocks_count + add); 1037 ext4_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks); 1038 ext4_debug("freed blocks %llu through %llu\n", o_blocks_count, 1039 o_blocks_count + add); 1040 if ((err = ext4_journal_stop(handle))) 1041 goto exit_put; 1042 if (test_opt(sb, DEBUG)) 1043 printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n", 1044 ext4_blocks_count(es)); 1045 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es, 1046 sizeof(struct ext4_super_block)); 1047 exit_put: 1048 return err; 1049 } /* ext4_group_extend */ 1050