resize.c 32.6 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
/*
 *  linux/fs/ext3/resize.c
 *
 * Support for resizing an ext3 filesystem while it is mounted.
 *
 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
 *
 * This could probably be made into a module, because it is not often in use.
 */


#define EXT3FS_DEBUG

#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/ext3_jbd.h>

#include <linux/errno.h>
#include <linux/slab.h>


#define outside(b, first, last)	((b) < (first) || (b) >= (last))
#define inside(b, first, last)	((b) >= (first) && (b) < (last))

static int verify_group_input(struct super_block *sb,
			      struct ext3_new_group_data *input)
{
	struct ext3_sb_info *sbi = EXT3_SB(sb);
	struct ext3_super_block *es = sbi->s_es;
30 31
	ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
	ext3_fsblk_t end = start + input->blocks_count;
L
Linus Torvalds 已提交
32
	unsigned group = input->group;
33
	ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
L
Linus Torvalds 已提交
34 35 36
	unsigned overhead = ext3_bg_has_super(sb, group) ?
		(1 + ext3_bg_num_gdb(sb, group) +
		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
37
	ext3_fsblk_t metaend = start + overhead;
L
Linus Torvalds 已提交
38
	struct buffer_head *bh = NULL;
39
	ext3_grpblk_t free_blocks_count;
L
Linus Torvalds 已提交
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
	int err = -EINVAL;

	input->free_blocks_count = free_blocks_count =
		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
		       "(%d free, %u reserved)\n",
		       ext3_bg_has_super(sb, input->group) ? "normal" :
		       "no-super", input->group, input->blocks_count,
		       free_blocks_count, input->reserved_blocks);

	if (group != sbi->s_groups_count)
		ext3_warning(sb, __FUNCTION__,
			     "Cannot add at group %u (only %lu groups)",
			     input->group, sbi->s_groups_count);
	else if ((start - le32_to_cpu(es->s_first_data_block)) %
		 EXT3_BLOCKS_PER_GROUP(sb))
		ext3_warning(sb, __FUNCTION__, "Last group not full");
	else if (input->reserved_blocks > input->blocks_count / 5)
		ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
			     input->reserved_blocks);
	else if (free_blocks_count < 0)
		ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
			     input->blocks_count);
	else if (!(bh = sb_bread(sb, end - 1)))
66 67
		ext3_warning(sb, __FUNCTION__,
			     "Cannot read last block ("E3FSBLK")",
L
Linus Torvalds 已提交
68 69 70 71 72 73 74 75 76 77 78 79
			     end - 1);
	else if (outside(input->block_bitmap, start, end))
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap not in group (block %u)",
			     input->block_bitmap);
	else if (outside(input->inode_bitmap, start, end))
		ext3_warning(sb, __FUNCTION__,
			     "Inode bitmap not in group (block %u)",
			     input->inode_bitmap);
	else if (outside(input->inode_table, start, end) ||
	         outside(itend - 1, start, end))
		ext3_warning(sb, __FUNCTION__,
80
			     "Inode table not in group (blocks %u-"E3FSBLK")",
L
Linus Torvalds 已提交
81 82 83 84 85 86 87
			     input->inode_table, itend - 1);
	else if (input->inode_bitmap == input->block_bitmap)
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap same as inode bitmap (%u)",
			     input->block_bitmap);
	else if (inside(input->block_bitmap, input->inode_table, itend))
		ext3_warning(sb, __FUNCTION__,
88
			     "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
L
Linus Torvalds 已提交
89 90 91
			     input->block_bitmap, input->inode_table, itend-1);
	else if (inside(input->inode_bitmap, input->inode_table, itend))
		ext3_warning(sb, __FUNCTION__,
92
			     "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
L
Linus Torvalds 已提交
93 94 95
			     input->inode_bitmap, input->inode_table, itend-1);
	else if (inside(input->block_bitmap, start, metaend))
		ext3_warning(sb, __FUNCTION__,
96 97
			     "Block bitmap (%u) in GDT table"
			     " ("E3FSBLK"-"E3FSBLK")",
L
Linus Torvalds 已提交
98 99 100
			     input->block_bitmap, start, metaend - 1);
	else if (inside(input->inode_bitmap, start, metaend))
		ext3_warning(sb, __FUNCTION__,
101 102
			     "Inode bitmap (%u) in GDT table"
			     " ("E3FSBLK"-"E3FSBLK")",
L
Linus Torvalds 已提交
103 104 105 106
			     input->inode_bitmap, start, metaend - 1);
	else if (inside(input->inode_table, start, metaend) ||
	         inside(itend - 1, start, metaend))
		ext3_warning(sb, __FUNCTION__,
107 108
			     "Inode table (%u-"E3FSBLK") overlaps"
			     "GDT table ("E3FSBLK"-"E3FSBLK")",
L
Linus Torvalds 已提交
109 110 111 112 113 114 115 116 117
			     input->inode_table, itend - 1, start, metaend - 1);
	else
		err = 0;
	brelse(bh);

	return err;
}

static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
118
				  ext3_fsblk_t blk)
L
Linus Torvalds 已提交
119 120 121 122 123
{
	struct buffer_head *bh;
	int err;

	bh = sb_getblk(sb, blk);
124 125
	if (!bh)
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
	if ((err = ext3_journal_get_write_access(handle, bh))) {
		brelse(bh);
		bh = ERR_PTR(err);
	} else {
		lock_buffer(bh);
		memset(bh->b_data, 0, sb->s_blocksize);
		set_buffer_uptodate(bh);
		unlock_buffer(bh);
	}

	return bh;
}

/*
 * To avoid calling the atomic setbit hundreds or thousands of times, we only
 * need to use it within a single byte (to ensure we get endianness right).
 * We can use memset for the rest of the bitmap as there are no other users.
 */
static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
{
	int i;

	if (start_bit >= end_bit)
		return;

	ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
		ext3_set_bit(i, bitmap);
	if (i < end_bit)
		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
}

/*
 * Set up the block and inode bitmaps, and the inode table for the new group.
 * This doesn't need to be part of the main transaction, since we are only
 * changing blocks outside the actual filesystem.  We still do journaling to
 * ensure the recovery is correct in case of a failure just after resize.
 * If any part of this fails, we simply abort the resize.
 */
static int setup_new_group_blocks(struct super_block *sb,
				  struct ext3_new_group_data *input)
{
	struct ext3_sb_info *sbi = EXT3_SB(sb);
169
	ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
L
Linus Torvalds 已提交
170 171 172 173 174
	int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
		le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
	unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
	struct buffer_head *bh;
	handle_t *handle;
175
	ext3_fsblk_t block;
176
	ext3_grpblk_t bit;
L
Linus Torvalds 已提交
177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
	int i;
	int err = 0, err2;

	handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
				       2 + sbi->s_itb_per_group);
	if (IS_ERR(handle))
		return PTR_ERR(handle);

	lock_super(sb);
	if (input->group != sbi->s_groups_count) {
		err = -EBUSY;
		goto exit_journal;
	}

	if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
		err = PTR_ERR(bh);
		goto exit_journal;
	}

	if (ext3_bg_has_super(sb, input->group)) {
		ext3_debug("mark backup superblock %#04lx (+0)\n", start);
		ext3_set_bit(0, bh->b_data);
	}

	/* Copy all of the GDT blocks into the backup in this group */
	for (i = 0, bit = 1, block = start + 1;
	     i < gdblocks; i++, block++, bit++) {
		struct buffer_head *gdb;

		ext3_debug("update backup group %#04lx (+%d)\n", block, bit);

		gdb = sb_getblk(sb, block);
209 210 211 212
		if (!gdb) {
			err = -EIO;
			goto exit_bh;
		}
L
Linus Torvalds 已提交
213 214 215 216 217
		if ((err = ext3_journal_get_write_access(handle, gdb))) {
			brelse(gdb);
			goto exit_bh;
		}
		lock_buffer(bh);
218
		memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
L
Linus Torvalds 已提交
219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
		set_buffer_uptodate(gdb);
		unlock_buffer(bh);
		ext3_journal_dirty_metadata(handle, gdb);
		ext3_set_bit(bit, bh->b_data);
		brelse(gdb);
	}

	/* Zero out all of the reserved backup group descriptor table blocks */
	for (i = 0, bit = gdblocks + 1, block = start + bit;
	     i < reserved_gdb; i++, block++, bit++) {
		struct buffer_head *gdb;

		ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);

		if (IS_ERR(gdb = bclean(handle, sb, block))) {
			err = PTR_ERR(bh);
			goto exit_bh;
		}
		ext3_journal_dirty_metadata(handle, gdb);
		ext3_set_bit(bit, bh->b_data);
		brelse(gdb);
	}
	ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
		   input->block_bitmap - start);
	ext3_set_bit(input->block_bitmap - start, bh->b_data);
	ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
		   input->inode_bitmap - start);
	ext3_set_bit(input->inode_bitmap - start, bh->b_data);

	/* Zero out all of the inode table blocks */
	for (i = 0, block = input->inode_table, bit = block - start;
	     i < sbi->s_itb_per_group; i++, bit++, block++) {
		struct buffer_head *it;

253
		ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
L
Linus Torvalds 已提交
254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332
		if (IS_ERR(it = bclean(handle, sb, block))) {
			err = PTR_ERR(it);
			goto exit_bh;
		}
		ext3_journal_dirty_metadata(handle, it);
		brelse(it);
		ext3_set_bit(bit, bh->b_data);
	}
	mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
			bh->b_data);
	ext3_journal_dirty_metadata(handle, bh);
	brelse(bh);

	/* Mark unused entries in inode bitmap used */
	ext3_debug("clear inode bitmap %#04x (+%ld)\n",
		   input->inode_bitmap, input->inode_bitmap - start);
	if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
		err = PTR_ERR(bh);
		goto exit_journal;
	}

	mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
			bh->b_data);
	ext3_journal_dirty_metadata(handle, bh);
exit_bh:
	brelse(bh);

exit_journal:
	unlock_super(sb);
	if ((err2 = ext3_journal_stop(handle)) && !err)
		err = err2;

	return err;
}

/*
 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
 * calling this for the first time.  In a sparse filesystem it will be the
 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 */
static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
				  unsigned *five, unsigned *seven)
{
	unsigned *min = three;
	int mult = 3;
	unsigned ret;

	if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
					EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
		ret = *min;
		*min += 1;
		return ret;
	}

	if (*five < *min) {
		min = five;
		mult = 5;
	}
	if (*seven < *min) {
		min = seven;
		mult = 7;
	}

	ret = *min;
	*min *= mult;

	return ret;
}

/*
 * Check that all of the backup GDT blocks are held in the primary GDT block.
 * It is assumed that they are stored in group order.  Returns the number of
 * groups in current filesystem that have BACKUPS, or -ve error code.
 */
static int verify_reserved_gdb(struct super_block *sb,
			       struct buffer_head *primary)
{
333
	const ext3_fsblk_t blk = primary->b_blocknr;
L
Linus Torvalds 已提交
334 335 336 337 338
	const unsigned long end = EXT3_SB(sb)->s_groups_count;
	unsigned three = 1;
	unsigned five = 5;
	unsigned seven = 7;
	unsigned grp;
339
	__le32 *p = (__le32 *)primary->b_data;
L
Linus Torvalds 已提交
340 341 342 343 344
	int gdbackups = 0;

	while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
		if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
			ext3_warning(sb, __FUNCTION__,
345 346
				     "reserved GDT "E3FSBLK
				     " missing grp %d ("E3FSBLK")",
L
Linus Torvalds 已提交
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377
				     blk, grp,
				     grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
			return -EINVAL;
		}
		if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
			return -EFBIG;
	}

	return gdbackups;
}

/*
 * Called when we need to bring a reserved group descriptor table block into
 * use from the resize inode.  The primary copy of the new GDT block currently
 * is an indirect block (under the double indirect block in the resize inode).
 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 * block, in group order.  Even though we know all the block numbers we need,
 * we check to ensure that the resize inode has actually reserved these blocks.
 *
 * Don't need to update the block bitmaps because the blocks are still in use.
 *
 * We get all of the error cases out of the way, so that we are sure to not
 * fail once we start modifying the data on disk, because JBD has no rollback.
 */
static int add_new_gdb(handle_t *handle, struct inode *inode,
		       struct ext3_new_group_data *input,
		       struct buffer_head **primary)
{
	struct super_block *sb = inode->i_sb;
	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
	unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
378
	ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
L
Linus Torvalds 已提交
379 380 381 382
	struct buffer_head **o_group_desc, **n_group_desc;
	struct buffer_head *dind;
	int gdbackups;
	struct ext3_iloc iloc;
383
	__le32 *data;
L
Linus Torvalds 已提交
384 385 386 387 388 389 390 391 392 393 394 395 396 397 398
	int err;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG
		       "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
		       gdb_num);

	/*
	 * If we are not using the primary superblock/GDT copy don't resize,
	 * because the user tools have no way of handling this.  Probably a
	 * bad time to do it anyways.
	 */
	if (EXT3_SB(sb)->s_sbh->b_blocknr !=
	    le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
		ext3_warning(sb, __FUNCTION__,
399
			"won't resize using backup superblock at %llu",
L
Linus Torvalds 已提交
400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419
			(unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
		return -EPERM;
	}

	*primary = sb_bread(sb, gdblock);
	if (!*primary)
		return -EIO;

	if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
		err = gdbackups;
		goto exit_bh;
	}

	data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
	dind = sb_bread(sb, le32_to_cpu(*data));
	if (!dind) {
		err = -EIO;
		goto exit_bh;
	}

420
	data = (__le32 *)dind->b_data;
L
Linus Torvalds 已提交
421 422
	if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
		ext3_warning(sb, __FUNCTION__,
423
			     "new group %u GDT block "E3FSBLK" not reserved",
L
Linus Torvalds 已提交
424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520
			     input->group, gdblock);
		err = -EINVAL;
		goto exit_dind;
	}

	if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
		goto exit_dind;

	if ((err = ext3_journal_get_write_access(handle, *primary)))
		goto exit_sbh;

	if ((err = ext3_journal_get_write_access(handle, dind)))
		goto exit_primary;

	/* ext3_reserve_inode_write() gets a reference on the iloc */
	if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
		goto exit_dindj;

	n_group_desc = (struct buffer_head **)kmalloc((gdb_num + 1) *
				sizeof(struct buffer_head *), GFP_KERNEL);
	if (!n_group_desc) {
		err = -ENOMEM;
		ext3_warning (sb, __FUNCTION__,
			      "not enough memory for %lu groups", gdb_num + 1);
		goto exit_inode;
	}

	/*
	 * Finally, we have all of the possible failures behind us...
	 *
	 * Remove new GDT block from inode double-indirect block and clear out
	 * the new GDT block for use (which also "frees" the backup GDT blocks
	 * from the reserved inode).  We don't need to change the bitmaps for
	 * these blocks, because they are marked as in-use from being in the
	 * reserved inode, and will become GDT blocks (primary and backup).
	 */
	data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
	ext3_journal_dirty_metadata(handle, dind);
	brelse(dind);
	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
	ext3_mark_iloc_dirty(handle, inode, &iloc);
	memset((*primary)->b_data, 0, sb->s_blocksize);
	ext3_journal_dirty_metadata(handle, *primary);

	o_group_desc = EXT3_SB(sb)->s_group_desc;
	memcpy(n_group_desc, o_group_desc,
	       EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
	n_group_desc[gdb_num] = *primary;
	EXT3_SB(sb)->s_group_desc = n_group_desc;
	EXT3_SB(sb)->s_gdb_count++;
	kfree(o_group_desc);

	es->s_reserved_gdt_blocks =
		cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
	ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);

	return 0;

exit_inode:
	//ext3_journal_release_buffer(handle, iloc.bh);
	brelse(iloc.bh);
exit_dindj:
	//ext3_journal_release_buffer(handle, dind);
exit_primary:
	//ext3_journal_release_buffer(handle, *primary);
exit_sbh:
	//ext3_journal_release_buffer(handle, *primary);
exit_dind:
	brelse(dind);
exit_bh:
	brelse(*primary);

	ext3_debug("leaving with error %d\n", err);
	return err;
}

/*
 * Called when we are adding a new group which has a backup copy of each of
 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 * We need to add these reserved backup GDT blocks to the resize inode, so
 * that they are kept for future resizing and not allocated to files.
 *
 * Each reserved backup GDT block will go into a different indirect block.
 * The indirect blocks are actually the primary reserved GDT blocks,
 * so we know in advance what their block numbers are.  We only get the
 * double-indirect block to verify it is pointing to the primary reserved
 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 * backup GDT blocks are stored in their reserved primary GDT block.
 */
static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
			      struct ext3_new_group_data *input)
{
	struct super_block *sb = inode->i_sb;
	int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
	struct buffer_head **primary;
	struct buffer_head *dind;
	struct ext3_iloc iloc;
521
	ext3_fsblk_t blk;
522
	__le32 *data, *end;
L
Linus Torvalds 已提交
523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538
	int gdbackups = 0;
	int res, i;
	int err;

	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
	if (!primary)
		return -ENOMEM;

	data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
	dind = sb_bread(sb, le32_to_cpu(*data));
	if (!dind) {
		err = -EIO;
		goto exit_free;
	}

	blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
539 540
	data = (__le32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
	end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
L
Linus Torvalds 已提交
541 542 543 544 545

	/* Get each reserved primary GDT block and verify it holds backups */
	for (res = 0; res < reserved_gdb; res++, blk++) {
		if (le32_to_cpu(*data) != blk) {
			ext3_warning(sb, __FUNCTION__,
546 547
				     "reserved block "E3FSBLK
				     " not at offset %ld",
548 549
				     blk,
				     (long)(data - (__le32 *)dind->b_data));
L
Linus Torvalds 已提交
550 551 552 553 554 555 556 557 558 559 560 561 562 563
			err = -EINVAL;
			goto exit_bh;
		}
		primary[res] = sb_bread(sb, blk);
		if (!primary[res]) {
			err = -EIO;
			goto exit_bh;
		}
		if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
			brelse(primary[res]);
			err = gdbackups;
			goto exit_bh;
		}
		if (++data >= end)
564
			data = (__le32 *)dind->b_data;
L
Linus Torvalds 已提交
565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587
	}

	for (i = 0; i < reserved_gdb; i++) {
		if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
			/*
			int j;
			for (j = 0; j < i; j++)
				ext3_journal_release_buffer(handle, primary[j]);
			 */
			goto exit_bh;
		}
	}

	if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
		goto exit_bh;

	/*
	 * Finally we can add each of the reserved backup GDT blocks from
	 * the new group to its reserved primary GDT block.
	 */
	blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
	for (i = 0; i < reserved_gdb; i++) {
		int err2;
588
		data = (__le32 *)primary[i]->b_data;
L
Linus Torvalds 已提交
589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656
		/* printk("reserving backup %lu[%u] = %lu\n",
		       primary[i]->b_blocknr, gdbackups,
		       blk + primary[i]->b_blocknr); */
		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
		err2 = ext3_journal_dirty_metadata(handle, primary[i]);
		if (!err)
			err = err2;
	}
	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
	ext3_mark_iloc_dirty(handle, inode, &iloc);

exit_bh:
	while (--res >= 0)
		brelse(primary[res]);
	brelse(dind);

exit_free:
	kfree(primary);

	return err;
}

/*
 * Update the backup copies of the ext3 metadata.  These don't need to be part
 * of the main resize transaction, because e2fsck will re-write them if there
 * is a problem (basically only OOM will cause a problem).  However, we
 * _should_ update the backups if possible, in case the primary gets trashed
 * for some reason and we need to run e2fsck from a backup superblock.  The
 * important part is that the new block and inode counts are in the backup
 * superblocks, and the location of the new group metadata in the GDT backups.
 *
 * We do not need lock_super() for this, because these blocks are not
 * otherwise touched by the filesystem code when it is mounted.  We don't
 * need to worry about last changing from sbi->s_groups_count, because the
 * worst that can happen is that we do not copy the full number of backups
 * at this time.  The resize which changed s_groups_count will backup again.
 */
static void update_backups(struct super_block *sb,
			   int blk_off, char *data, int size)
{
	struct ext3_sb_info *sbi = EXT3_SB(sb);
	const unsigned long last = sbi->s_groups_count;
	const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
	unsigned three = 1;
	unsigned five = 5;
	unsigned seven = 7;
	unsigned group;
	int rest = sb->s_blocksize - size;
	handle_t *handle;
	int err = 0, err2;

	handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
	if (IS_ERR(handle)) {
		group = 1;
		err = PTR_ERR(handle);
		goto exit_err;
	}

	while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
		struct buffer_head *bh;

		/* Out of journal space, and can't get more - abort - so sad */
		if (handle->h_buffer_credits == 0 &&
		    ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
		    (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
			break;

		bh = sb_getblk(sb, group * bpg + blk_off);
657 658 659 660
		if (!bh) {
			err = -EIO;
			break;
		}
661 662
		ext3_debug("update metadata backup %#04lx\n",
			  (unsigned long)bh->b_blocknr);
L
Linus Torvalds 已提交
663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
		if ((err = ext3_journal_get_write_access(handle, bh)))
			break;
		lock_buffer(bh);
		memcpy(bh->b_data, data, size);
		if (rest)
			memset(bh->b_data + size, 0, rest);
		set_buffer_uptodate(bh);
		unlock_buffer(bh);
		ext3_journal_dirty_metadata(handle, bh);
		brelse(bh);
	}
	if ((err2 = ext3_journal_stop(handle)) && !err)
		err = err2;

	/*
	 * Ugh! Need to have e2fsck write the backup copies.  It is too
	 * late to revert the resize, we shouldn't fail just because of
	 * the backup copies (they are only needed in case of corruption).
	 *
	 * However, if we got here we have a journal problem too, so we
	 * can't really start a transaction to mark the superblock.
	 * Chicken out and just set the flag on the hope it will be written
	 * to disk, and if not - we will simply wait until next fsck.
	 */
exit_err:
	if (err) {
		ext3_warning(sb, __FUNCTION__,
			     "can't update backup for group %d (err %d), "
691
			     "forcing fsck on next reboot", group, err);
L
Linus Torvalds 已提交
692
		sbi->s_mount_state &= ~EXT3_VALID_FS;
693
		sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
L
Linus Torvalds 已提交
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729
		mark_buffer_dirty(sbi->s_sbh);
	}
}

/* Add group descriptor data to an existing or new group descriptor block.
 * Ensure we handle all possible error conditions _before_ we start modifying
 * the filesystem, because we cannot abort the transaction and not have it
 * write the data to disk.
 *
 * If we are on a GDT block boundary, we need to get the reserved GDT block.
 * Otherwise, we may need to add backup GDT blocks for a sparse group.
 *
 * We only need to hold the superblock lock while we are actually adding
 * in the new group's counts to the superblock.  Prior to that we have
 * not really "added" the group at all.  We re-check that we are still
 * adding in the last group in case things have changed since verifying.
 */
int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
{
	struct ext3_sb_info *sbi = EXT3_SB(sb);
	struct ext3_super_block *es = sbi->s_es;
	int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
	struct buffer_head *primary = NULL;
	struct ext3_group_desc *gdp;
	struct inode *inode = NULL;
	handle_t *handle;
	int gdb_off, gdb_num;
	int err, err2;

	gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
	gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);

	if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
					EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
		ext3_warning(sb, __FUNCTION__,
730
			     "Can't resize non-sparse filesystem further");
L
Linus Torvalds 已提交
731 732 733
		return -EPERM;
	}

734 735 736 737 738 739 740 741 742 743 744 745
	if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
	    le32_to_cpu(es->s_blocks_count)) {
		ext3_warning(sb, __FUNCTION__, "blocks_count overflow\n");
		return -EINVAL;
	}

	if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
	    le32_to_cpu(es->s_inodes_count)) {
		ext3_warning(sb, __FUNCTION__, "inodes_count overflow\n");
		return -EINVAL;
	}

L
Linus Torvalds 已提交
746 747 748 749
	if (reserved_gdb || gdb_off == 0) {
		if (!EXT3_HAS_COMPAT_FEATURE(sb,
					     EXT3_FEATURE_COMPAT_RESIZE_INODE)){
			ext3_warning(sb, __FUNCTION__,
750
				     "No reserved GDT blocks, can't resize");
L
Linus Torvalds 已提交
751 752 753 754 755
			return -EPERM;
		}
		inode = iget(sb, EXT3_RESIZE_INO);
		if (!inode || is_bad_inode(inode)) {
			ext3_warning(sb, __FUNCTION__,
756
				     "Error opening resize inode");
L
Linus Torvalds 已提交
757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783
			iput(inode);
			return -ENOENT;
		}
	}

	if ((err = verify_group_input(sb, input)))
		goto exit_put;

	if ((err = setup_new_group_blocks(sb, input)))
		goto exit_put;

	/*
	 * We will always be modifying at least the superblock and a GDT
	 * block.  If we are adding a group past the last current GDT block,
	 * we will also modify the inode and the dindirect block.  If we
	 * are adding a group with superblock/GDT backups  we will also
	 * modify each of the reserved GDT dindirect blocks.
	 */
	handle = ext3_journal_start_sb(sb,
				       ext3_bg_has_super(sb, input->group) ?
				       3 + reserved_gdb : 4);
	if (IS_ERR(handle)) {
		err = PTR_ERR(handle);
		goto exit_put;
	}

	lock_super(sb);
784
	if (input->group != sbi->s_groups_count) {
L
Linus Torvalds 已提交
785
		ext3_warning(sb, __FUNCTION__,
786
			     "multiple resizers run on filesystem!");
787
		err = -EBUSY;
L
Linus Torvalds 已提交
788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818
		goto exit_journal;
	}

	if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
		goto exit_journal;

	/*
	 * We will only either add reserved group blocks to a backup group
	 * or remove reserved blocks for the first group in a new group block.
	 * Doing both would be mean more complex code, and sane people don't
	 * use non-sparse filesystems anymore.  This is already checked above.
	 */
	if (gdb_off) {
		primary = sbi->s_group_desc[gdb_num];
		if ((err = ext3_journal_get_write_access(handle, primary)))
			goto exit_journal;

		if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
		    (err = reserve_backup_gdb(handle, inode, input)))
			goto exit_journal;
	} else if ((err = add_new_gdb(handle, inode, input, &primary)))
		goto exit_journal;

	/*
	 * OK, now we've set up the new group.  Time to make it active.
	 *
	 * Current kernels don't lock all allocations via lock_super(),
	 * so we have to be safe wrt. concurrent accesses the group
	 * data.  So we need to be careful to set all of the relevant
	 * group descriptor data etc. *before* we enable the group.
	 *
819
	 * The key field here is sbi->s_groups_count: as long as
L
Linus Torvalds 已提交
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878
	 * that retains its old value, nobody is going to access the new
	 * group.
	 *
	 * So first we update all the descriptor metadata for the new
	 * group; then we update the total disk blocks count; then we
	 * update the groups count to enable the group; then finally we
	 * update the free space counts so that the system can start
	 * using the new disk blocks.
	 */

	/* Update group descriptor block for new group */
	gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;

	gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
	gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
	gdp->bg_inode_table = cpu_to_le32(input->inode_table);
	gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
	gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));

	/*
	 * Make the new blocks and inodes valid next.  We do this before
	 * increasing the group count so that once the group is enabled,
	 * all of its blocks and inodes are already valid.
	 *
	 * We always allocate group-by-group, then block-by-block or
	 * inode-by-inode within a group, so enabling these
	 * blocks/inodes before the group is live won't actually let us
	 * allocate the new space yet.
	 */
	es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
		input->blocks_count);
	es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
		EXT3_INODES_PER_GROUP(sb));

	/*
	 * We need to protect s_groups_count against other CPUs seeing
	 * inconsistent state in the superblock.
	 *
	 * The precise rules we use are:
	 *
	 * * Writers of s_groups_count *must* hold lock_super
	 * AND
	 * * Writers must perform a smp_wmb() after updating all dependent
	 *   data and before modifying the groups count
	 *
	 * * Readers must hold lock_super() over the access
	 * OR
	 * * Readers must perform an smp_rmb() after reading the groups count
	 *   and before reading any dependent data.
	 *
	 * NB. These rules can be relaxed when checking the group count
	 * while freeing data, as we can only allocate from a block
	 * group after serialising against the group count, and we can
	 * only then free after serialising in turn against that
	 * allocation.
	 */
	smp_wmb();

	/* Update the global fs size fields */
879
	sbi->s_groups_count++;
L
Linus Torvalds 已提交
880 881 882 883 884 885 886 887 888 889 890 891 892 893

	ext3_journal_dirty_metadata(handle, primary);

	/* Update the reserved block counts only once the new group is
	 * active. */
	es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
		input->reserved_blocks);

	/* Update the free space counts */
	percpu_counter_mod(&sbi->s_freeblocks_counter,
			   input->free_blocks_count);
	percpu_counter_mod(&sbi->s_freeinodes_counter,
			   EXT3_INODES_PER_GROUP(sb));

894
	ext3_journal_dirty_metadata(handle, sbi->s_sbh);
L
Linus Torvalds 已提交
895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921
	sb->s_dirt = 1;

exit_journal:
	unlock_super(sb);
	if ((err2 = ext3_journal_stop(handle)) && !err)
		err = err2;
	if (!err) {
		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
			       sizeof(struct ext3_super_block));
		update_backups(sb, primary->b_blocknr, primary->b_data,
			       primary->b_size);
	}
exit_put:
	iput(inode);
	return err;
} /* ext3_group_add */

/* Extend the filesystem to the new number of blocks specified.  This entry
 * point is only used to extend the current filesystem to the end of the last
 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
 * for emergencies (because it has no dependencies on reserved blocks).
 *
 * If we _really_ wanted, we could use default values to call ext3_group_add()
 * allow the "remount" trick to work for arbitrary resizing, assuming enough
 * GDT blocks are reserved to grow to the desired size.
 */
int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
922
		      ext3_fsblk_t n_blocks_count)
L
Linus Torvalds 已提交
923
{
924
	ext3_fsblk_t o_blocks_count;
L
Linus Torvalds 已提交
925
	unsigned long o_groups_count;
926 927
	ext3_grpblk_t last;
	ext3_grpblk_t add;
L
Linus Torvalds 已提交
928 929
	struct buffer_head * bh;
	handle_t *handle;
930 931
	int err;
	unsigned long freed_blocks;
L
Linus Torvalds 已提交
932 933 934 935 936 937 938 939

	/* We don't need to worry about locking wrt other resizers just
	 * yet: we're going to revalidate es->s_blocks_count after
	 * taking lock_super() below. */
	o_blocks_count = le32_to_cpu(es->s_blocks_count);
	o_groups_count = EXT3_SB(sb)->s_groups_count;

	if (test_opt(sb, DEBUG))
940
		printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
L
Linus Torvalds 已提交
941 942 943 944 945
		       o_blocks_count, n_blocks_count);

	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
		return 0;

946 947 948 949 950 951 952 953 954 955
	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
		printk(KERN_ERR "EXT3-fs: filesystem on %s:"
			" too large to resize to %lu blocks safely\n",
			sb->s_id, n_blocks_count);
		if (sizeof(sector_t) < 8)
			ext3_warning(sb, __FUNCTION__,
			"CONFIG_LBD not enabled\n");
		return -EINVAL;
	}

L
Linus Torvalds 已提交
956 957 958 959 960 961 962 963 964 965 966 967
	if (n_blocks_count < o_blocks_count) {
		ext3_warning(sb, __FUNCTION__,
			     "can't shrink FS - resize aborted");
		return -EBUSY;
	}

	/* Handle the remaining blocks in the last group only. */
	last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
		EXT3_BLOCKS_PER_GROUP(sb);

	if (last == 0) {
		ext3_warning(sb, __FUNCTION__,
968
			     "need to use ext2online to resize further");
L
Linus Torvalds 已提交
969 970 971 972 973
		return -EPERM;
	}

	add = EXT3_BLOCKS_PER_GROUP(sb) - last;

974 975 976 977 978
	if (o_blocks_count + add < o_blocks_count) {
		ext3_warning(sb, __FUNCTION__, "blocks_count overflow");
		return -EINVAL;
	}

L
Linus Torvalds 已提交
979 980 981 982 983
	if (o_blocks_count + add > n_blocks_count)
		add = n_blocks_count - o_blocks_count;

	if (o_blocks_count + add < n_blocks_count)
		ext3_warning(sb, __FUNCTION__,
984 985
			     "will only finish group ("E3FSBLK
			     " blocks, %u new)",
L
Linus Torvalds 已提交
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009
			     o_blocks_count + add, add);

	/* See if the device is actually as big as what was requested */
	bh = sb_bread(sb, o_blocks_count + add -1);
	if (!bh) {
		ext3_warning(sb, __FUNCTION__,
			     "can't read last block, resize aborted");
		return -ENOSPC;
	}
	brelse(bh);

	/* We will update the superblock, one block bitmap, and
	 * one group descriptor via ext3_free_blocks().
	 */
	handle = ext3_journal_start_sb(sb, 3);
	if (IS_ERR(handle)) {
		err = PTR_ERR(handle);
		ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
		goto exit_put;
	}

	lock_super(sb);
	if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
		ext3_warning(sb, __FUNCTION__,
1010
			     "multiple resizers run on filesystem!");
1011
		unlock_super(sb);
L
Linus Torvalds 已提交
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
		err = -EBUSY;
		goto exit_put;
	}

	if ((err = ext3_journal_get_write_access(handle,
						 EXT3_SB(sb)->s_sbh))) {
		ext3_warning(sb, __FUNCTION__,
			     "error %d on journal write access", err);
		unlock_super(sb);
		ext3_journal_stop(handle);
		goto exit_put;
	}
	es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
	ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
	sb->s_dirt = 1;
	unlock_super(sb);
1028
	ext3_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
L
Linus Torvalds 已提交
1029 1030
		   o_blocks_count + add);
	ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1031
	ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
L
Linus Torvalds 已提交
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
		   o_blocks_count + add);
	if ((err = ext3_journal_stop(handle)))
		goto exit_put;
	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
		       le32_to_cpu(es->s_blocks_count));
	update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
		       sizeof(struct ext3_super_block));
exit_put:
	return err;
} /* ext3_group_extend */