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/ext4_jbd2.h> 15 16#include <linux/errno.h> 17#include <linux/slab.h> 18 19 20#define outside(b, first, last) ((b) < (first) || (b) >= (last)) 21#define inside(b, first, last) ((b) >= (first) && (b) < (last)) 22 23static int verify_group_input(struct super_block *sb, 24 struct ext4_new_group_data *input) 25{ 26 struct ext4_sb_info *sbi = EXT4_SB(sb); 27 struct ext4_super_block *es = sbi->s_es; 28 ext4_fsblk_t start = ext4_blocks_count(es); 29 ext4_fsblk_t end = start + input->blocks_count; 30 unsigned group = input->group; 31 ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group; 32 unsigned overhead = ext4_bg_has_super(sb, group) ? 33 (1 + ext4_bg_num_gdb(sb, group) + 34 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0; 35 ext4_fsblk_t metaend = start + overhead; 36 struct buffer_head *bh = NULL; 37 ext4_grpblk_t free_blocks_count, offset; 38 int err = -EINVAL; 39 40 input->free_blocks_count = free_blocks_count = 41 input->blocks_count - 2 - overhead - sbi->s_itb_per_group; 42 43 if (test_opt(sb, DEBUG)) 44 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks " 45 "(%d free, %u reserved)\n", 46 ext4_bg_has_super(sb, input->group) ? "normal" : 47 "no-super", input->group, input->blocks_count, 48 free_blocks_count, input->reserved_blocks); 49 50 ext4_get_group_no_and_offset(sb, start, NULL, &offset); 51 if (group != sbi->s_groups_count) 52 ext4_warning(sb, __FUNCTION__, 53 "Cannot add at group %u (only %lu groups)", 54 input->group, sbi->s_groups_count); 55 else if (offset != 0) 56 ext4_warning(sb, __FUNCTION__, "Last group not full"); 57 else if (input->reserved_blocks > input->blocks_count / 5) 58 ext4_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)", 59 input->reserved_blocks); 60 else if (free_blocks_count < 0) 61 ext4_warning(sb, __FUNCTION__, "Bad blocks count %u", 62 input->blocks_count); 63 else if (!(bh = sb_bread(sb, end - 1))) 64 ext4_warning(sb, __FUNCTION__, 65 "Cannot read last block (%llu)", 66 end - 1); 67 else if (outside(input->block_bitmap, start, end)) 68 ext4_warning(sb, __FUNCTION__, 69 "Block bitmap not in group (block %llu)", 70 (unsigned long long)input->block_bitmap); 71 else if (outside(input->inode_bitmap, start, end)) 72 ext4_warning(sb, __FUNCTION__, 73 "Inode bitmap not in group (block %llu)", 74 (unsigned long long)input->inode_bitmap); 75 else if (outside(input->inode_table, start, end) || 76 outside(itend - 1, start, end)) 77 ext4_warning(sb, __FUNCTION__, 78 "Inode table not in group (blocks %llu-%llu)", 79 (unsigned long long)input->inode_table, itend - 1); 80 else if (input->inode_bitmap == input->block_bitmap) 81 ext4_warning(sb, __FUNCTION__, 82 "Block bitmap same as inode bitmap (%llu)", 83 (unsigned long long)input->block_bitmap); 84 else if (inside(input->block_bitmap, input->inode_table, itend)) 85 ext4_warning(sb, __FUNCTION__, 86 "Block bitmap (%llu) in inode table (%llu-%llu)", 87 (unsigned long long)input->block_bitmap, 88 (unsigned long long)input->inode_table, itend - 1); 89 else if (inside(input->inode_bitmap, input->inode_table, itend)) 90 ext4_warning(sb, __FUNCTION__, 91 "Inode bitmap (%llu) in inode table (%llu-%llu)", 92 (unsigned long long)input->inode_bitmap, 93 (unsigned long long)input->inode_table, itend - 1); 94 else if (inside(input->block_bitmap, start, metaend)) 95 ext4_warning(sb, __FUNCTION__, 96 "Block bitmap (%llu) in GDT table" 97 " (%llu-%llu)", 98 (unsigned long long)input->block_bitmap, 99 start, metaend - 1); 100 else if (inside(input->inode_bitmap, start, metaend)) 101 ext4_warning(sb, __FUNCTION__, 102 "Inode bitmap (%llu) in GDT table" 103 " (%llu-%llu)", 104 (unsigned long long)input->inode_bitmap, 105 start, metaend - 1); 106 else if (inside(input->inode_table, start, metaend) || 107 inside(itend - 1, start, metaend)) 108 ext4_warning(sb, __FUNCTION__, 109 "Inode table (%llu-%llu) overlaps" 110 "GDT table (%llu-%llu)", 111 (unsigned long long)input->inode_table, 112 itend - 1, start, metaend - 1); 113 else 114 err = 0; 115 brelse(bh); 116 117 return err; 118} 119 120static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, 121 ext4_fsblk_t blk) 122{ 123 struct buffer_head *bh; 124 int err; 125 126 bh = sb_getblk(sb, blk); 127 if (!bh) 128 return ERR_PTR(-EIO); 129 if ((err = ext4_journal_get_write_access(handle, bh))) { 130 brelse(bh); 131 bh = ERR_PTR(err); 132 } else { 133 lock_buffer(bh); 134 memset(bh->b_data, 0, sb->s_blocksize); 135 set_buffer_uptodate(bh); 136 unlock_buffer(bh); 137 } 138 139 return bh; 140} 141 142/* 143 * To avoid calling the atomic setbit hundreds or thousands of times, we only 144 * need to use it within a single byte (to ensure we get endianness right). 145 * We can use memset for the rest of the bitmap as there are no other users. 146 */ 147static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap) 148{ 149 int i; 150 151 if (start_bit >= end_bit) 152 return; 153 154 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit); 155 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++) 156 ext4_set_bit(i, bitmap); 157 if (i < end_bit) 158 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3); 159} 160 161/* 162 * Set up the block and inode bitmaps, and the inode table for the new group. 163 * This doesn't need to be part of the main transaction, since we are only 164 * changing blocks outside the actual filesystem. We still do journaling to 165 * ensure the recovery is correct in case of a failure just after resize. 166 * If any part of this fails, we simply abort the resize. 167 */ 168static int setup_new_group_blocks(struct super_block *sb, 169 struct ext4_new_group_data *input) 170{ 171 struct ext4_sb_info *sbi = EXT4_SB(sb); 172 ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group); 173 int reserved_gdb = ext4_bg_has_super(sb, input->group) ? 174 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0; 175 unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group); 176 struct buffer_head *bh; 177 handle_t *handle; 178 ext4_fsblk_t block; 179 ext4_grpblk_t bit; 180 int i; 181 int err = 0, err2; 182 183 handle = ext4_journal_start_sb(sb, reserved_gdb + gdblocks + 184 2 + sbi->s_itb_per_group); 185 if (IS_ERR(handle)) 186 return PTR_ERR(handle); 187 188 lock_super(sb); 189 if (input->group != sbi->s_groups_count) { 190 err = -EBUSY; 191 goto exit_journal; 192 } 193 194 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) { 195 err = PTR_ERR(bh); 196 goto exit_journal; 197 } 198 199 if (ext4_bg_has_super(sb, input->group)) { 200 ext4_debug("mark backup superblock %#04lx (+0)\n", start); 201 ext4_set_bit(0, bh->b_data); 202 } 203 204 /* Copy all of the GDT blocks into the backup in this group */ 205 for (i = 0, bit = 1, block = start + 1; 206 i < gdblocks; i++, block++, bit++) { 207 struct buffer_head *gdb; 208 209 ext4_debug("update backup group %#04lx (+%d)\n", block, bit); 210 211 gdb = sb_getblk(sb, block); 212 if (!gdb) { 213 err = -EIO; 214 goto exit_bh; 215 } 216 if ((err = ext4_journal_get_write_access(handle, gdb))) { 217 brelse(gdb); 218 goto exit_bh; 219 } 220 lock_buffer(bh); 221 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size); 222 set_buffer_uptodate(gdb); 223 unlock_buffer(bh); 224 ext4_journal_dirty_metadata(handle, gdb); 225 ext4_set_bit(bit, bh->b_data); 226 brelse(gdb); 227 } 228 229 /* Zero out all of the reserved backup group descriptor table blocks */ 230 for (i = 0, bit = gdblocks + 1, block = start + bit; 231 i < reserved_gdb; i++, block++, bit++) { 232 struct buffer_head *gdb; 233 234 ext4_debug("clear reserved block %#04lx (+%d)\n", block, bit); 235 236 if (IS_ERR(gdb = bclean(handle, sb, block))) { 237 err = PTR_ERR(bh); 238 goto exit_bh; 239 } 240 ext4_journal_dirty_metadata(handle, gdb); 241 ext4_set_bit(bit, bh->b_data); 242 brelse(gdb); 243 } 244 ext4_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap, 245 input->block_bitmap - start); 246 ext4_set_bit(input->block_bitmap - start, bh->b_data); 247 ext4_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap, 248 input->inode_bitmap - start); 249 ext4_set_bit(input->inode_bitmap - start, bh->b_data); 250 251 /* Zero out all of the inode table blocks */ 252 for (i = 0, block = input->inode_table, bit = block - start; 253 i < sbi->s_itb_per_group; i++, bit++, block++) { 254 struct buffer_head *it; 255 256 ext4_debug("clear inode block %#04lx (+%d)\n", block, bit); 257 if (IS_ERR(it = bclean(handle, sb, block))) { 258 err = PTR_ERR(it); 259 goto exit_bh; 260 } 261 ext4_journal_dirty_metadata(handle, it); 262 brelse(it); 263 ext4_set_bit(bit, bh->b_data); 264 } 265 mark_bitmap_end(input->blocks_count, EXT4_BLOCKS_PER_GROUP(sb), 266 bh->b_data); 267 ext4_journal_dirty_metadata(handle, bh); 268 brelse(bh); 269 270 /* Mark unused entries in inode bitmap used */ 271 ext4_debug("clear inode bitmap %#04x (+%ld)\n", 272 input->inode_bitmap, input->inode_bitmap - start); 273 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) { 274 err = PTR_ERR(bh); 275 goto exit_journal; 276 } 277 278 mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb), 279 bh->b_data); 280 ext4_journal_dirty_metadata(handle, bh); 281exit_bh: 282 brelse(bh); 283 284exit_journal: 285 unlock_super(sb); 286 if ((err2 = ext4_journal_stop(handle)) && !err) 287 err = err2; 288 289 return err; 290} 291 292 293/* 294 * Iterate through the groups which hold BACKUP superblock/GDT copies in an 295 * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before 296 * calling this for the first time. In a sparse filesystem it will be the 297 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... 298 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... 299 */ 300static unsigned ext4_list_backups(struct super_block *sb, unsigned *three, 301 unsigned *five, unsigned *seven) 302{ 303 unsigned *min = three; 304 int mult = 3; 305 unsigned ret; 306 307 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, 308 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 309 ret = *min; 310 *min += 1; 311 return ret; 312 } 313 314 if (*five < *min) { 315 min = five; 316 mult = 5; 317 } 318 if (*seven < *min) { 319 min = seven; 320 mult = 7; 321 } 322 323 ret = *min; 324 *min *= mult; 325 326 return ret; 327} 328 329/* 330 * Check that all of the backup GDT blocks are held in the primary GDT block. 331 * It is assumed that they are stored in group order. Returns the number of 332 * groups in current filesystem that have BACKUPS, or -ve error code. 333 */ 334static int verify_reserved_gdb(struct super_block *sb, 335 struct buffer_head *primary) 336{ 337 const ext4_fsblk_t blk = primary->b_blocknr; 338 const unsigned long end = EXT4_SB(sb)->s_groups_count; 339 unsigned three = 1; 340 unsigned five = 5; 341 unsigned seven = 7; 342 unsigned grp; 343 __le32 *p = (__le32 *)primary->b_data; 344 int gdbackups = 0; 345 346 while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) { 347 if (le32_to_cpu(*p++) != 348 grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){ 349 ext4_warning(sb, __FUNCTION__, 350 "reserved GDT %llu" 351 " missing grp %d (%llu)", 352 blk, grp, 353 grp * 354 (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) + 355 blk); 356 return -EINVAL; 357 } 358 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb)) 359 return -EFBIG; 360 } 361 362 return gdbackups; 363} 364 365/* 366 * Called when we need to bring a reserved group descriptor table block into 367 * use from the resize inode. The primary copy of the new GDT block currently 368 * is an indirect block (under the double indirect block in the resize inode). 369 * The new backup GDT blocks will be stored as leaf blocks in this indirect 370 * block, in group order. Even though we know all the block numbers we need, 371 * we check to ensure that the resize inode has actually reserved these blocks. 372 * 373 * Don't need to update the block bitmaps because the blocks are still in use. 374 * 375 * We get all of the error cases out of the way, so that we are sure to not 376 * fail once we start modifying the data on disk, because JBD has no rollback. 377 */ 378static int add_new_gdb(handle_t *handle, struct inode *inode, 379 struct ext4_new_group_data *input, 380 struct buffer_head **primary) 381{ 382 struct super_block *sb = inode->i_sb; 383 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 384 unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); 385 ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num; 386 struct buffer_head **o_group_desc, **n_group_desc; 387 struct buffer_head *dind; 388 int gdbackups; 389 struct ext4_iloc iloc; 390 __le32 *data; 391 int err; 392 393 if (test_opt(sb, DEBUG)) 394 printk(KERN_DEBUG 395 "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n", 396 gdb_num); 397 398 /* 399 * If we are not using the primary superblock/GDT copy don't resize, 400 * because the user tools have no way of handling this. Probably a 401 * bad time to do it anyways. 402 */ 403 if (EXT4_SB(sb)->s_sbh->b_blocknr != 404 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { 405 ext4_warning(sb, __FUNCTION__, 406 "won't resize using backup superblock at %llu", 407 (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); 408 return -EPERM; 409 } 410 411 *primary = sb_bread(sb, gdblock); 412 if (!*primary) 413 return -EIO; 414 415 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) { 416 err = gdbackups; 417 goto exit_bh; 418 } 419 420 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; 421 dind = sb_bread(sb, le32_to_cpu(*data)); 422 if (!dind) { 423 err = -EIO; 424 goto exit_bh; 425 } 426 427 data = (__le32 *)dind->b_data; 428 if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) { 429 ext4_warning(sb, __FUNCTION__, 430 "new group %u GDT block %llu not reserved", 431 input->group, gdblock); 432 err = -EINVAL; 433 goto exit_dind; 434 } 435 436 if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh))) 437 goto exit_dind; 438 439 if ((err = ext4_journal_get_write_access(handle, *primary))) 440 goto exit_sbh; 441 442 if ((err = ext4_journal_get_write_access(handle, dind))) 443 goto exit_primary; 444 445 /* ext4_reserve_inode_write() gets a reference on the iloc */ 446 if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) 447 goto exit_dindj; 448 449 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *), 450 GFP_KERNEL); 451 if (!n_group_desc) { 452 err = -ENOMEM; 453 ext4_warning (sb, __FUNCTION__, 454 "not enough memory for %lu groups", gdb_num + 1); 455 goto exit_inode; 456 } 457 458 /* 459 * Finally, we have all of the possible failures behind us... 460 * 461 * Remove new GDT block from inode double-indirect block and clear out 462 * the new GDT block for use (which also "frees" the backup GDT blocks 463 * from the reserved inode). We don't need to change the bitmaps for 464 * these blocks, because they are marked as in-use from being in the 465 * reserved inode, and will become GDT blocks (primary and backup). 466 */ 467 data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0; 468 ext4_journal_dirty_metadata(handle, dind); 469 brelse(dind); 470 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9; 471 ext4_mark_iloc_dirty(handle, inode, &iloc); 472 memset((*primary)->b_data, 0, sb->s_blocksize); 473 ext4_journal_dirty_metadata(handle, *primary); 474 475 o_group_desc = EXT4_SB(sb)->s_group_desc; 476 memcpy(n_group_desc, o_group_desc, 477 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); 478 n_group_desc[gdb_num] = *primary; 479 EXT4_SB(sb)->s_group_desc = n_group_desc; 480 EXT4_SB(sb)->s_gdb_count++; 481 kfree(o_group_desc); 482 483 es->s_reserved_gdt_blocks = 484 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1); 485 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); 486 487 return 0; 488 489exit_inode: 490 //ext4_journal_release_buffer(handle, iloc.bh); 491 brelse(iloc.bh); 492exit_dindj: 493 //ext4_journal_release_buffer(handle, dind); 494exit_primary: 495 //ext4_journal_release_buffer(handle, *primary); 496exit_sbh: 497 //ext4_journal_release_buffer(handle, *primary); 498exit_dind: 499 brelse(dind); 500exit_bh: 501 brelse(*primary); 502 503 ext4_debug("leaving with error %d\n", err); 504 return err; 505} 506 507/* 508 * Called when we are adding a new group which has a backup copy of each of 509 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks. 510 * We need to add these reserved backup GDT blocks to the resize inode, so 511 * that they are kept for future resizing and not allocated to files. 512 * 513 * Each reserved backup GDT block will go into a different indirect block. 514 * The indirect blocks are actually the primary reserved GDT blocks, 515 * so we know in advance what their block numbers are. We only get the 516 * double-indirect block to verify it is pointing to the primary reserved 517 * GDT blocks so we don't overwrite a data block by accident. The reserved 518 * backup GDT blocks are stored in their reserved primary GDT block. 519 */ 520static int reserve_backup_gdb(handle_t *handle, struct inode *inode, 521 struct ext4_new_group_data *input) 522{ 523 struct super_block *sb = inode->i_sb; 524 int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks); 525 struct buffer_head **primary; 526 struct buffer_head *dind; 527 struct ext4_iloc iloc; 528 ext4_fsblk_t blk; 529 __le32 *data, *end; 530 int gdbackups = 0; 531 int res, i; 532 int err; 533 534 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL); 535 if (!primary) 536 return -ENOMEM; 537 538 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; 539 dind = sb_bread(sb, le32_to_cpu(*data)); 540 if (!dind) { 541 err = -EIO; 542 goto exit_free; 543 } 544 545 blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count; 546 data = (__le32 *)dind->b_data + EXT4_SB(sb)->s_gdb_count; 547 end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb); 548 549 /* Get each reserved primary GDT block and verify it holds backups */ 550 for (res = 0; res < reserved_gdb; res++, blk++) { 551 if (le32_to_cpu(*data) != blk) { 552 ext4_warning(sb, __FUNCTION__, 553 "reserved block %llu" 554 " not at offset %ld", 555 blk, 556 (long)(data - (__le32 *)dind->b_data)); 557 err = -EINVAL; 558 goto exit_bh; 559 } 560 primary[res] = sb_bread(sb, blk); 561 if (!primary[res]) { 562 err = -EIO; 563 goto exit_bh; 564 } 565 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) { 566 brelse(primary[res]); 567 err = gdbackups; 568 goto exit_bh; 569 } 570 if (++data >= end) 571 data = (__le32 *)dind->b_data; 572 } 573 574 for (i = 0; i < reserved_gdb; i++) { 575 if ((err = ext4_journal_get_write_access(handle, primary[i]))) { 576 /* 577 int j; 578 for (j = 0; j < i; j++) 579 ext4_journal_release_buffer(handle, primary[j]); 580 */ 581 goto exit_bh; 582 } 583 } 584 585 if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) 586 goto exit_bh; 587 588 /* 589 * Finally we can add each of the reserved backup GDT blocks from 590 * the new group to its reserved primary GDT block. 591 */ 592 blk = input->group * EXT4_BLOCKS_PER_GROUP(sb); 593 for (i = 0; i < reserved_gdb; i++) { 594 int err2; 595 data = (__le32 *)primary[i]->b_data; 596 /* printk("reserving backup %lu[%u] = %lu\n", 597 primary[i]->b_blocknr, gdbackups, 598 blk + primary[i]->b_blocknr); */ 599 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr); 600 err2 = ext4_journal_dirty_metadata(handle, primary[i]); 601 if (!err) 602 err = err2; 603 } 604 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9; 605 ext4_mark_iloc_dirty(handle, inode, &iloc); 606 607exit_bh: 608 while (--res >= 0) 609 brelse(primary[res]); 610 brelse(dind); 611 612exit_free: 613 kfree(primary); 614 615 return err; 616} 617 618/* 619 * Update the backup copies of the ext4 metadata. These don't need to be part 620 * of the main resize transaction, because e2fsck will re-write them if there 621 * is a problem (basically only OOM will cause a problem). However, we 622 * _should_ update the backups if possible, in case the primary gets trashed 623 * for some reason and we need to run e2fsck from a backup superblock. The 624 * important part is that the new block and inode counts are in the backup 625 * superblocks, and the location of the new group metadata in the GDT backups. 626 * 627 * We do not need lock_super() for this, because these blocks are not 628 * otherwise touched by the filesystem code when it is mounted. We don't 629 * need to worry about last changing from sbi->s_groups_count, because the 630 * worst that can happen is that we do not copy the full number of backups 631 * at this time. The resize which changed s_groups_count will backup again. 632 */ 633static void update_backups(struct super_block *sb, 634 int blk_off, char *data, int size) 635{ 636 struct ext4_sb_info *sbi = EXT4_SB(sb); 637 const unsigned long last = sbi->s_groups_count; 638 const int bpg = EXT4_BLOCKS_PER_GROUP(sb); 639 unsigned three = 1; 640 unsigned five = 5; 641 unsigned seven = 7; 642 unsigned group; 643 int rest = sb->s_blocksize - size; 644 handle_t *handle; 645 int err = 0, err2; 646 647 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA); 648 if (IS_ERR(handle)) { 649 group = 1; 650 err = PTR_ERR(handle); 651 goto exit_err; 652 } 653 654 while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) { 655 struct buffer_head *bh; 656 657 /* Out of journal space, and can't get more - abort - so sad */ 658 if (handle->h_buffer_credits == 0 && 659 ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) && 660 (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA))) 661 break; 662 663 bh = sb_getblk(sb, group * bpg + blk_off); 664 if (!bh) { 665 err = -EIO; 666 break; 667 } 668 ext4_debug("update metadata backup %#04lx\n", 669 (unsigned long)bh->b_blocknr); 670 if ((err = ext4_journal_get_write_access(handle, bh))) 671 break; 672 lock_buffer(bh); 673 memcpy(bh->b_data, data, size); 674 if (rest) 675 memset(bh->b_data + size, 0, rest); 676 set_buffer_uptodate(bh); 677 unlock_buffer(bh); 678 ext4_journal_dirty_metadata(handle, bh); 679 brelse(bh); 680 } 681 if ((err2 = ext4_journal_stop(handle)) && !err) 682 err = err2; 683 684 /* 685 * Ugh! Need to have e2fsck write the backup copies. It is too 686 * late to revert the resize, we shouldn't fail just because of 687 * the backup copies (they are only needed in case of corruption). 688 * 689 * However, if we got here we have a journal problem too, so we 690 * can't really start a transaction to mark the superblock. 691 * Chicken out and just set the flag on the hope it will be written 692 * to disk, and if not - we will simply wait until next fsck. 693 */ 694exit_err: 695 if (err) { 696 ext4_warning(sb, __FUNCTION__, 697 "can't update backup for group %d (err %d), " 698 "forcing fsck on next reboot", group, err); 699 sbi->s_mount_state &= ~EXT4_VALID_FS; 700 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS); 701 mark_buffer_dirty(sbi->s_sbh); 702 } 703} 704 705/* Add group descriptor data to an existing or new group descriptor block. 706 * Ensure we handle all possible error conditions _before_ we start modifying 707 * the filesystem, because we cannot abort the transaction and not have it 708 * write the data to disk. 709 * 710 * If we are on a GDT block boundary, we need to get the reserved GDT block. 711 * Otherwise, we may need to add backup GDT blocks for a sparse group. 712 * 713 * We only need to hold the superblock lock while we are actually adding 714 * in the new group's counts to the superblock. Prior to that we have 715 * not really "added" the group at all. We re-check that we are still 716 * adding in the last group in case things have changed since verifying. 717 */ 718int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) 719{ 720 struct ext4_sb_info *sbi = EXT4_SB(sb); 721 struct ext4_super_block *es = sbi->s_es; 722 int reserved_gdb = ext4_bg_has_super(sb, input->group) ? 723 le16_to_cpu(es->s_reserved_gdt_blocks) : 0; 724 struct buffer_head *primary = NULL; 725 struct ext4_group_desc *gdp; 726 struct inode *inode = NULL; 727 handle_t *handle; 728 int gdb_off, gdb_num; 729 int err, err2; 730 731 gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); 732 gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb); 733 734 if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb, 735 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 736 ext4_warning(sb, __FUNCTION__, 737 "Can't resize non-sparse filesystem further"); 738 return -EPERM; 739 } 740 741 if (ext4_blocks_count(es) + input->blocks_count < 742 ext4_blocks_count(es)) { 743 ext4_warning(sb, __FUNCTION__, "blocks_count overflow\n"); 744 return -EINVAL; 745 } 746 747 if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) < 748 le32_to_cpu(es->s_inodes_count)) { 749 ext4_warning(sb, __FUNCTION__, "inodes_count overflow\n"); 750 return -EINVAL; 751 } 752 753 if (reserved_gdb || gdb_off == 0) { 754 if (!EXT4_HAS_COMPAT_FEATURE(sb, 755 EXT4_FEATURE_COMPAT_RESIZE_INODE)){ 756 ext4_warning(sb, __FUNCTION__, 757 "No reserved GDT blocks, can't resize"); 758 return -EPERM; 759 } 760 inode = iget(sb, EXT4_RESIZE_INO); 761 if (!inode || is_bad_inode(inode)) { 762 ext4_warning(sb, __FUNCTION__, 763 "Error opening resize inode"); 764 iput(inode); 765 return -ENOENT; 766 } 767 } 768 769 if ((err = verify_group_input(sb, input))) 770 goto exit_put; 771 772 if ((err = setup_new_group_blocks(sb, input))) 773 goto exit_put; 774 775 /* 776 * We will always be modifying at least the superblock and a GDT 777 * block. If we are adding a group past the last current GDT block, 778 * we will also modify the inode and the dindirect block. If we 779 * are adding a group with superblock/GDT backups we will also 780 * modify each of the reserved GDT dindirect blocks. 781 */ 782 handle = ext4_journal_start_sb(sb, 783 ext4_bg_has_super(sb, input->group) ? 784 3 + reserved_gdb : 4); 785 if (IS_ERR(handle)) { 786 err = PTR_ERR(handle); 787 goto exit_put; 788 } 789 790 lock_super(sb); 791 if (input->group != sbi->s_groups_count) { 792 ext4_warning(sb, __FUNCTION__, 793 "multiple resizers run on filesystem!"); 794 err = -EBUSY; 795 goto exit_journal; 796 } 797 798 if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh))) 799 goto exit_journal; 800 801 /* 802 * We will only either add reserved group blocks to a backup group 803 * or remove reserved blocks for the first group in a new group block. 804 * Doing both would be mean more complex code, and sane people don't 805 * use non-sparse filesystems anymore. This is already checked above. 806 */ 807 if (gdb_off) { 808 primary = sbi->s_group_desc[gdb_num]; 809 if ((err = ext4_journal_get_write_access(handle, primary))) 810 goto exit_journal; 811 812 if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) && 813 (err = reserve_backup_gdb(handle, inode, input))) 814 goto exit_journal; 815 } else if ((err = add_new_gdb(handle, inode, input, &primary))) 816 goto exit_journal; 817 818 /* 819 * OK, now we've set up the new group. Time to make it active. 820 * 821 * Current kernels don't lock all allocations via lock_super(), 822 * so we have to be safe wrt. concurrent accesses the group 823 * data. So we need to be careful to set all of the relevant 824 * group descriptor data etc. *before* we enable the group. 825 * 826 * The key field here is sbi->s_groups_count: as long as 827 * that retains its old value, nobody is going to access the new 828 * group. 829 * 830 * So first we update all the descriptor metadata for the new 831 * group; then we update the total disk blocks count; then we 832 * update the groups count to enable the group; then finally we 833 * update the free space counts so that the system can start 834 * using the new disk blocks. 835 */ 836 837 /* Update group descriptor block for new group */ 838 gdp = (struct ext4_group_desc *)primary->b_data + gdb_off; 839 840 ext4_block_bitmap_set(sb, gdp, input->block_bitmap); 841 ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); 842 ext4_inode_table_set(sb, gdp, input->inode_table); 843 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count); 844 gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb)); 845 846 /* 847 * Make the new blocks and inodes valid next. We do this before 848 * increasing the group count so that once the group is enabled, 849 * all of its blocks and inodes are already valid. 850 * 851 * We always allocate group-by-group, then block-by-block or 852 * inode-by-inode within a group, so enabling these 853 * blocks/inodes before the group is live won't actually let us 854 * allocate the new space yet. 855 */ 856 ext4_blocks_count_set(es, ext4_blocks_count(es) + 857 input->blocks_count); 858 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) + 859 EXT4_INODES_PER_GROUP(sb)); 860 861 /* 862 * We need to protect s_groups_count against other CPUs seeing 863 * inconsistent state in the superblock. 864 * 865 * The precise rules we use are: 866 * 867 * * Writers of s_groups_count *must* hold lock_super 868 * AND 869 * * Writers must perform a smp_wmb() after updating all dependent 870 * data and before modifying the groups count 871 * 872 * * Readers must hold lock_super() over the access 873 * OR 874 * * Readers must perform an smp_rmb() after reading the groups count 875 * and before reading any dependent data. 876 * 877 * NB. These rules can be relaxed when checking the group count 878 * while freeing data, as we can only allocate from a block 879 * group after serialising against the group count, and we can 880 * only then free after serialising in turn against that 881 * allocation. 882 */ 883 smp_wmb(); 884 885 /* Update the global fs size fields */ 886 sbi->s_groups_count++; 887 888 ext4_journal_dirty_metadata(handle, primary); 889 890 /* Update the reserved block counts only once the new group is 891 * active. */ 892 ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) + 893 input->reserved_blocks); 894 895 /* Update the free space counts */ 896 percpu_counter_mod(&sbi->s_freeblocks_counter, 897 input->free_blocks_count); 898 percpu_counter_mod(&sbi->s_freeinodes_counter, 899 EXT4_INODES_PER_GROUP(sb)); 900 901 ext4_journal_dirty_metadata(handle, sbi->s_sbh); 902 sb->s_dirt = 1; 903 904exit_journal: 905 unlock_super(sb); 906 if ((err2 = ext4_journal_stop(handle)) && !err) 907 err = err2; 908 if (!err) { 909 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, 910 sizeof(struct ext4_super_block)); 911 update_backups(sb, primary->b_blocknr, primary->b_data, 912 primary->b_size); 913 } 914exit_put: 915 iput(inode); 916 return err; 917} /* ext4_group_add */ 918 919/* Extend the filesystem to the new number of blocks specified. This entry 920 * point is only used to extend the current filesystem to the end of the last 921 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>" 922 * for emergencies (because it has no dependencies on reserved blocks). 923 * 924 * If we _really_ wanted, we could use default values to call ext4_group_add() 925 * allow the "remount" trick to work for arbitrary resizing, assuming enough 926 * GDT blocks are reserved to grow to the desired size. 927 */ 928int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es, 929 ext4_fsblk_t n_blocks_count) 930{ 931 ext4_fsblk_t o_blocks_count; 932 unsigned long o_groups_count; 933 ext4_grpblk_t last; 934 ext4_grpblk_t add; 935 struct buffer_head * bh; 936 handle_t *handle; 937 int err; 938 unsigned long freed_blocks; 939 940 /* We don't need to worry about locking wrt other resizers just 941 * yet: we're going to revalidate es->s_blocks_count after 942 * taking lock_super() below. */ 943 o_blocks_count = ext4_blocks_count(es); 944 o_groups_count = EXT4_SB(sb)->s_groups_count; 945 946 if (test_opt(sb, DEBUG)) 947 printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n", 948 o_blocks_count, n_blocks_count); 949 950 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count) 951 return 0; 952 953 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { 954 printk(KERN_ERR "EXT4-fs: filesystem on %s:" 955 " too large to resize to %llu blocks safely\n", 956 sb->s_id, n_blocks_count); 957 if (sizeof(sector_t) < 8) 958 ext4_warning(sb, __FUNCTION__, 959 "CONFIG_LBD not enabled\n"); 960 return -EINVAL; 961 } 962 963 if (n_blocks_count < o_blocks_count) { 964 ext4_warning(sb, __FUNCTION__, 965 "can't shrink FS - resize aborted"); 966 return -EBUSY; 967 } 968 969 /* Handle the remaining blocks in the last group only. */ 970 ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last); 971 972 if (last == 0) { 973 ext4_warning(sb, __FUNCTION__, 974 "need to use ext2online to resize further"); 975 return -EPERM; 976 } 977 978 add = EXT4_BLOCKS_PER_GROUP(sb) - last; 979 980 if (o_blocks_count + add < o_blocks_count) { 981 ext4_warning(sb, __FUNCTION__, "blocks_count overflow"); 982 return -EINVAL; 983 } 984 985 if (o_blocks_count + add > n_blocks_count) 986 add = n_blocks_count - o_blocks_count; 987 988 if (o_blocks_count + add < n_blocks_count) 989 ext4_warning(sb, __FUNCTION__, 990 "will only finish group (%llu" 991 " blocks, %u new)", 992 o_blocks_count + add, add); 993 994 /* See if the device is actually as big as what was requested */ 995 bh = sb_bread(sb, o_blocks_count + add -1); 996 if (!bh) { 997 ext4_warning(sb, __FUNCTION__, 998 "can't read last block, resize aborted"); 999 return -ENOSPC; 1000 } 1001 brelse(bh); 1002 1003 /* We will update the superblock, one block bitmap, and 1004 * one group descriptor via ext4_free_blocks(). 1005 */ 1006 handle = ext4_journal_start_sb(sb, 3); 1007 if (IS_ERR(handle)) { 1008 err = PTR_ERR(handle); 1009 ext4_warning(sb, __FUNCTION__, "error %d on journal start",err); 1010 goto exit_put; 1011 } 1012 1013 lock_super(sb); 1014 if (o_blocks_count != ext4_blocks_count(es)) { 1015 ext4_warning(sb, __FUNCTION__, 1016 "multiple resizers run on filesystem!"); 1017 unlock_super(sb); 1018 err = -EBUSY; 1019 goto exit_put; 1020 } 1021 1022 if ((err = ext4_journal_get_write_access(handle, 1023 EXT4_SB(sb)->s_sbh))) { 1024 ext4_warning(sb, __FUNCTION__, 1025 "error %d on journal write access", err); 1026 unlock_super(sb); 1027 ext4_journal_stop(handle); 1028 goto exit_put; 1029 } 1030 ext4_blocks_count_set(es, o_blocks_count + add); 1031 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); 1032 sb->s_dirt = 1; 1033 unlock_super(sb); 1034 ext4_debug("freeing blocks %lu through %llu\n", o_blocks_count, 1035 o_blocks_count + add); 1036 ext4_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks); 1037 ext4_debug("freed blocks %llu through %llu\n", o_blocks_count, 1038 o_blocks_count + add); 1039 if ((err = ext4_journal_stop(handle))) 1040 goto exit_put; 1041 if (test_opt(sb, DEBUG)) 1042 printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n", 1043 ext4_blocks_count(es)); 1044 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es, 1045 sizeof(struct ext4_super_block)); 1046exit_put: 1047 return err; 1048} /* ext4_group_extend */ 1049