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/errno.h>
  15#include <linux/slab.h>
  16
  17#include "ext4_jbd2.h"
  18
  19int ext4_resize_begin(struct super_block *sb)
  20{
  21	int ret = 0;
  22
  23	if (!capable(CAP_SYS_RESOURCE))
  24		return -EPERM;
  25
  26	/*
  27	 * If we are not using the primary superblock/GDT copy don't resize,
  28         * because the user tools have no way of handling this.  Probably a
  29         * bad time to do it anyways.
  30         */
  31	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
  32	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  33		ext4_warning(sb, "won't resize using backup superblock at %llu",
  34			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  35		return -EPERM;
  36	}
  37
  38	/*
  39	 * We are not allowed to do online-resizing on a filesystem mounted
  40	 * with error, because it can destroy the filesystem easily.
  41	 */
  42	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  43		ext4_warning(sb, "There are errors in the filesystem, "
  44			     "so online resizing is not allowed\n");
  45		return -EPERM;
  46	}
  47
  48	if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
  49		ret = -EBUSY;
  50
  51	return ret;
  52}
  53
  54void ext4_resize_end(struct super_block *sb)
  55{
  56	clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
  57	smp_mb__after_atomic();
  58}
  59
  60static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  61					     ext4_group_t group) {
  62	return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  63	       EXT4_DESC_PER_BLOCK_BITS(sb);
  64}
  65
  66static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  67					     ext4_group_t group) {
  68	group = ext4_meta_bg_first_group(sb, group);
  69	return ext4_group_first_block_no(sb, group);
  70}
  71
  72static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  73						ext4_group_t group) {
  74	ext4_grpblk_t overhead;
  75	overhead = ext4_bg_num_gdb(sb, group);
  76	if (ext4_bg_has_super(sb, group))
  77		overhead += 1 +
  78			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  79	return overhead;
  80}
  81
  82#define outside(b, first, last)	((b) < (first) || (b) >= (last))
  83#define inside(b, first, last)	((b) >= (first) && (b) < (last))
  84
  85static int verify_group_input(struct super_block *sb,
  86			      struct ext4_new_group_data *input)
  87{
  88	struct ext4_sb_info *sbi = EXT4_SB(sb);
  89	struct ext4_super_block *es = sbi->s_es;
  90	ext4_fsblk_t start = ext4_blocks_count(es);
  91	ext4_fsblk_t end = start + input->blocks_count;
  92	ext4_group_t group = input->group;
  93	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  94	unsigned overhead;
  95	ext4_fsblk_t metaend;
  96	struct buffer_head *bh = NULL;
  97	ext4_grpblk_t free_blocks_count, offset;
  98	int err = -EINVAL;
  99
 100	if (group != sbi->s_groups_count) {
 101		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 102			     input->group, sbi->s_groups_count);
 103		return -EINVAL;
 104	}
 105
 106	overhead = ext4_group_overhead_blocks(sb, group);
 107	metaend = start + overhead;
 108	input->free_blocks_count = free_blocks_count =
 109		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 110
 111	if (test_opt(sb, DEBUG))
 112		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 113		       "(%d free, %u reserved)\n",
 114		       ext4_bg_has_super(sb, input->group) ? "normal" :
 115		       "no-super", input->group, input->blocks_count,
 116		       free_blocks_count, input->reserved_blocks);
 117
 118	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 119	if (offset != 0)
 120			ext4_warning(sb, "Last group not full");
 121	else if (input->reserved_blocks > input->blocks_count / 5)
 122		ext4_warning(sb, "Reserved blocks too high (%u)",
 123			     input->reserved_blocks);
 124	else if (free_blocks_count < 0)
 125		ext4_warning(sb, "Bad blocks count %u",
 126			     input->blocks_count);
 127	else if (!(bh = sb_bread(sb, end - 1)))
 128		ext4_warning(sb, "Cannot read last block (%llu)",
 129			     end - 1);
 130	else if (outside(input->block_bitmap, start, end))
 131		ext4_warning(sb, "Block bitmap not in group (block %llu)",
 132			     (unsigned long long)input->block_bitmap);
 133	else if (outside(input->inode_bitmap, start, end))
 134		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 135			     (unsigned long long)input->inode_bitmap);
 136	else if (outside(input->inode_table, start, end) ||
 137		 outside(itend - 1, start, end))
 138		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 139			     (unsigned long long)input->inode_table, itend - 1);
 140	else if (input->inode_bitmap == input->block_bitmap)
 141		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 142			     (unsigned long long)input->block_bitmap);
 143	else if (inside(input->block_bitmap, input->inode_table, itend))
 144		ext4_warning(sb, "Block bitmap (%llu) in inode table "
 145			     "(%llu-%llu)",
 146			     (unsigned long long)input->block_bitmap,
 147			     (unsigned long long)input->inode_table, itend - 1);
 148	else if (inside(input->inode_bitmap, input->inode_table, itend))
 149		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 150			     "(%llu-%llu)",
 151			     (unsigned long long)input->inode_bitmap,
 152			     (unsigned long long)input->inode_table, itend - 1);
 153	else if (inside(input->block_bitmap, start, metaend))
 154		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 155			     (unsigned long long)input->block_bitmap,
 156			     start, metaend - 1);
 157	else if (inside(input->inode_bitmap, start, metaend))
 158		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 159			     (unsigned long long)input->inode_bitmap,
 160			     start, metaend - 1);
 161	else if (inside(input->inode_table, start, metaend) ||
 162		 inside(itend - 1, start, metaend))
 163		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 164			     "(%llu-%llu)",
 165			     (unsigned long long)input->inode_table,
 166			     itend - 1, start, metaend - 1);
 167	else
 168		err = 0;
 169	brelse(bh);
 170
 171	return err;
 172}
 173
 174/*
 175 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 176 * group each time.
 177 */
 178struct ext4_new_flex_group_data {
 179	struct ext4_new_group_data *groups;	/* new_group_data for groups
 180						   in the flex group */
 181	__u16 *bg_flags;			/* block group flags of groups
 182						   in @groups */
 183	ext4_group_t count;			/* number of groups in @groups
 184						 */
 185};
 186
 187/*
 188 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 189 * @flexbg_size.
 190 *
 191 * Returns NULL on failure otherwise address of the allocated structure.
 192 */
 193static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 194{
 195	struct ext4_new_flex_group_data *flex_gd;
 196
 197	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 198	if (flex_gd == NULL)
 199		goto out3;
 200
 201	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 202		goto out2;
 203	flex_gd->count = flexbg_size;
 204
 205	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 206				  flexbg_size, GFP_NOFS);
 207	if (flex_gd->groups == NULL)
 208		goto out2;
 209
 210	flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 211	if (flex_gd->bg_flags == NULL)
 212		goto out1;
 213
 214	return flex_gd;
 215
 216out1:
 217	kfree(flex_gd->groups);
 218out2:
 219	kfree(flex_gd);
 220out3:
 221	return NULL;
 222}
 223
 224static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 225{
 226	kfree(flex_gd->bg_flags);
 227	kfree(flex_gd->groups);
 228	kfree(flex_gd);
 229}
 230
 231/*
 232 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 233 * and inode tables for a flex group.
 234 *
 235 * This function is used by 64bit-resize.  Note that this function allocates
 236 * group tables from the 1st group of groups contained by @flexgd, which may
 237 * be a partial of a flex group.
 238 *
 239 * @sb: super block of fs to which the groups belongs
 240 *
 241 * Returns 0 on a successful allocation of the metadata blocks in the
 242 * block group.
 243 */
 244static int ext4_alloc_group_tables(struct super_block *sb,
 245				struct ext4_new_flex_group_data *flex_gd,
 246				int flexbg_size)
 247{
 248	struct ext4_new_group_data *group_data = flex_gd->groups;
 249	ext4_fsblk_t start_blk;
 250	ext4_fsblk_t last_blk;
 251	ext4_group_t src_group;
 252	ext4_group_t bb_index = 0;
 253	ext4_group_t ib_index = 0;
 254	ext4_group_t it_index = 0;
 255	ext4_group_t group;
 256	ext4_group_t last_group;
 257	unsigned overhead;
 258	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 259
 260	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 261
 262	src_group = group_data[0].group;
 263	last_group  = src_group + flex_gd->count - 1;
 264
 265	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 266	       (last_group & ~(flexbg_size - 1))));
 267next_group:
 268	group = group_data[0].group;
 269	if (src_group >= group_data[0].group + flex_gd->count)
 270		return -ENOSPC;
 271	start_blk = ext4_group_first_block_no(sb, src_group);
 272	last_blk = start_blk + group_data[src_group - group].blocks_count;
 273
 274	overhead = ext4_group_overhead_blocks(sb, src_group);
 275
 276	start_blk += overhead;
 277
 278	/* We collect contiguous blocks as much as possible. */
 279	src_group++;
 280	for (; src_group <= last_group; src_group++) {
 281		overhead = ext4_group_overhead_blocks(sb, src_group);
 282		if (overhead == 0)
 283			last_blk += group_data[src_group - group].blocks_count;
 284		else
 285			break;
 286	}
 287
 288	/* Allocate block bitmaps */
 289	for (; bb_index < flex_gd->count; bb_index++) {
 290		if (start_blk >= last_blk)
 291			goto next_group;
 292		group_data[bb_index].block_bitmap = start_blk++;
 293		group = ext4_get_group_number(sb, start_blk - 1);
 294		group -= group_data[0].group;
 295		group_data[group].free_blocks_count--;
 296		flex_gd->bg_flags[group] &= uninit_mask;
 297	}
 298
 299	/* Allocate inode bitmaps */
 300	for (; ib_index < flex_gd->count; ib_index++) {
 301		if (start_blk >= last_blk)
 302			goto next_group;
 303		group_data[ib_index].inode_bitmap = start_blk++;
 304		group = ext4_get_group_number(sb, start_blk - 1);
 305		group -= group_data[0].group;
 306		group_data[group].free_blocks_count--;
 307		flex_gd->bg_flags[group] &= uninit_mask;
 308	}
 309
 310	/* Allocate inode tables */
 311	for (; it_index < flex_gd->count; it_index++) {
 312		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 313		ext4_fsblk_t next_group_start;
 314
 315		if (start_blk + itb > last_blk)
 316			goto next_group;
 317		group_data[it_index].inode_table = start_blk;
 318		group = ext4_get_group_number(sb, start_blk);
 319		next_group_start = ext4_group_first_block_no(sb, group + 1);
 320		group -= group_data[0].group;
 321
 322		if (start_blk + itb > next_group_start) {
 323			flex_gd->bg_flags[group + 1] &= uninit_mask;
 324			overhead = start_blk + itb - next_group_start;
 325			group_data[group + 1].free_blocks_count -= overhead;
 326			itb -= overhead;
 327		}
 328
 329		group_data[group].free_blocks_count -= itb;
 330		flex_gd->bg_flags[group] &= uninit_mask;
 331		start_blk += EXT4_SB(sb)->s_itb_per_group;
 332	}
 333
 334	if (test_opt(sb, DEBUG)) {
 335		int i;
 336		group = group_data[0].group;
 337
 338		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 339		       "%d groups, flexbg size is %d:\n", flex_gd->count,
 340		       flexbg_size);
 341
 342		for (i = 0; i < flex_gd->count; i++) {
 343			printk(KERN_DEBUG "adding %s group %u: %u "
 344			       "blocks (%d free)\n",
 345			       ext4_bg_has_super(sb, group + i) ? "normal" :
 346			       "no-super", group + i,
 347			       group_data[i].blocks_count,
 348			       group_data[i].free_blocks_count);
 349		}
 350	}
 351	return 0;
 352}
 353
 354static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 355				  ext4_fsblk_t blk)
 356{
 357	struct buffer_head *bh;
 358	int err;
 359
 360	bh = sb_getblk(sb, blk);
 361	if (unlikely(!bh))
 362		return ERR_PTR(-ENOMEM);
 363	BUFFER_TRACE(bh, "get_write_access");
 364	if ((err = ext4_journal_get_write_access(handle, bh))) {
 365		brelse(bh);
 366		bh = ERR_PTR(err);
 367	} else {
 368		memset(bh->b_data, 0, sb->s_blocksize);
 369		set_buffer_uptodate(bh);
 370	}
 371
 372	return bh;
 373}
 374
 375/*
 376 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 377 * If that fails, restart the transaction & regain write access for the
 378 * buffer head which is used for block_bitmap modifications.
 379 */
 380static int extend_or_restart_transaction(handle_t *handle, int thresh)
 381{
 382	int err;
 383
 384	if (ext4_handle_has_enough_credits(handle, thresh))
 385		return 0;
 386
 387	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 388	if (err < 0)
 389		return err;
 390	if (err) {
 391		err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 392		if (err)
 393			return err;
 394	}
 395
 396	return 0;
 397}
 398
 399/*
 400 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 401 *
 402 * Helper function for ext4_setup_new_group_blocks() which set .
 403 *
 404 * @sb: super block
 405 * @handle: journal handle
 406 * @flex_gd: flex group data
 407 */
 408static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 409			struct ext4_new_flex_group_data *flex_gd,
 410			ext4_fsblk_t block, ext4_group_t count)
 411{
 412	ext4_group_t count2;
 413
 414	ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 415	for (count2 = count; count > 0; count -= count2, block += count2) {
 416		ext4_fsblk_t start;
 417		struct buffer_head *bh;
 418		ext4_group_t group;
 419		int err;
 420
 421		group = ext4_get_group_number(sb, block);
 422		start = ext4_group_first_block_no(sb, group);
 423		group -= flex_gd->groups[0].group;
 424
 425		count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
 426		if (count2 > count)
 427			count2 = count;
 428
 429		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 430			BUG_ON(flex_gd->count > 1);
 431			continue;
 432		}
 433
 434		err = extend_or_restart_transaction(handle, 1);
 435		if (err)
 436			return err;
 437
 438		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 439		if (unlikely(!bh))
 440			return -ENOMEM;
 441
 442		BUFFER_TRACE(bh, "get_write_access");
 443		err = ext4_journal_get_write_access(handle, bh);
 444		if (err)
 445			return err;
 446		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 447			   block - start, count2);
 448		ext4_set_bits(bh->b_data, block - start, count2);
 449
 450		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 451		if (unlikely(err))
 452			return err;
 453		brelse(bh);
 454	}
 455
 456	return 0;
 457}
 458
 459/*
 460 * Set up the block and inode bitmaps, and the inode table for the new groups.
 461 * This doesn't need to be part of the main transaction, since we are only
 462 * changing blocks outside the actual filesystem.  We still do journaling to
 463 * ensure the recovery is correct in case of a failure just after resize.
 464 * If any part of this fails, we simply abort the resize.
 465 *
 466 * setup_new_flex_group_blocks handles a flex group as follow:
 467 *  1. copy super block and GDT, and initialize group tables if necessary.
 468 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 469 *     super block and GDT.
 470 *  2. allocate group tables in block bitmaps, that is, set bits in block
 471 *     bitmap for blocks taken by group tables.
 472 */
 473static int setup_new_flex_group_blocks(struct super_block *sb,
 474				struct ext4_new_flex_group_data *flex_gd)
 475{
 476	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 477	ext4_fsblk_t start;
 478	ext4_fsblk_t block;
 479	struct ext4_sb_info *sbi = EXT4_SB(sb);
 480	struct ext4_super_block *es = sbi->s_es;
 481	struct ext4_new_group_data *group_data = flex_gd->groups;
 482	__u16 *bg_flags = flex_gd->bg_flags;
 483	handle_t *handle;
 484	ext4_group_t group, count;
 485	struct buffer_head *bh = NULL;
 486	int reserved_gdb, i, j, err = 0, err2;
 487	int meta_bg;
 488
 489	BUG_ON(!flex_gd->count || !group_data ||
 490	       group_data[0].group != sbi->s_groups_count);
 491
 492	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 493	meta_bg = ext4_has_feature_meta_bg(sb);
 494
 495	/* This transaction may be extended/restarted along the way */
 496	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 497	if (IS_ERR(handle))
 498		return PTR_ERR(handle);
 499
 500	group = group_data[0].group;
 501	for (i = 0; i < flex_gd->count; i++, group++) {
 502		unsigned long gdblocks;
 503		ext4_grpblk_t overhead;
 504
 505		gdblocks = ext4_bg_num_gdb(sb, group);
 506		start = ext4_group_first_block_no(sb, group);
 507
 508		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 509			goto handle_itb;
 510
 511		if (meta_bg == 1) {
 512			ext4_group_t first_group;
 513			first_group = ext4_meta_bg_first_group(sb, group);
 514			if (first_group != group + 1 &&
 515			    first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 516				goto handle_itb;
 517		}
 518
 519		block = start + ext4_bg_has_super(sb, group);
 520		/* Copy all of the GDT blocks into the backup in this group */
 521		for (j = 0; j < gdblocks; j++, block++) {
 522			struct buffer_head *gdb;
 523
 524			ext4_debug("update backup group %#04llx\n", block);
 525			err = extend_or_restart_transaction(handle, 1);
 526			if (err)
 527				goto out;
 528
 529			gdb = sb_getblk(sb, block);
 530			if (unlikely(!gdb)) {
 531				err = -ENOMEM;
 532				goto out;
 533			}
 534
 535			BUFFER_TRACE(gdb, "get_write_access");
 536			err = ext4_journal_get_write_access(handle, gdb);
 537			if (err) {
 538				brelse(gdb);
 539				goto out;
 540			}
 541			memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 542			       gdb->b_size);
 543			set_buffer_uptodate(gdb);
 544
 545			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 546			if (unlikely(err)) {
 547				brelse(gdb);
 548				goto out;
 549			}
 550			brelse(gdb);
 551		}
 552
 553		/* Zero out all of the reserved backup group descriptor
 554		 * table blocks
 555		 */
 556		if (ext4_bg_has_super(sb, group)) {
 557			err = sb_issue_zeroout(sb, gdblocks + start + 1,
 558					reserved_gdb, GFP_NOFS);
 559			if (err)
 560				goto out;
 561		}
 562
 563handle_itb:
 564		/* Initialize group tables of the grop @group */
 565		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 566			goto handle_bb;
 567
 568		/* Zero out all of the inode table blocks */
 569		block = group_data[i].inode_table;
 570		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 571			   block, sbi->s_itb_per_group);
 572		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 573				       GFP_NOFS);
 574		if (err)
 575			goto out;
 576
 577handle_bb:
 578		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 579			goto handle_ib;
 580
 581		/* Initialize block bitmap of the @group */
 582		block = group_data[i].block_bitmap;
 583		err = extend_or_restart_transaction(handle, 1);
 584		if (err)
 585			goto out;
 586
 587		bh = bclean(handle, sb, block);
 588		if (IS_ERR(bh)) {
 589			err = PTR_ERR(bh);
 590			bh = NULL;
 591			goto out;
 592		}
 593		overhead = ext4_group_overhead_blocks(sb, group);
 594		if (overhead != 0) {
 595			ext4_debug("mark backup superblock %#04llx (+0)\n",
 596				   start);
 597			ext4_set_bits(bh->b_data, 0, overhead);
 598		}
 599		ext4_mark_bitmap_end(group_data[i].blocks_count,
 600				     sb->s_blocksize * 8, bh->b_data);
 601		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 602		if (err)
 603			goto out;
 604		brelse(bh);
 605
 606handle_ib:
 607		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 608			continue;
 609
 610		/* Initialize inode bitmap of the @group */
 611		block = group_data[i].inode_bitmap;
 612		err = extend_or_restart_transaction(handle, 1);
 613		if (err)
 614			goto out;
 615		/* Mark unused entries in inode bitmap used */
 616		bh = bclean(handle, sb, block);
 617		if (IS_ERR(bh)) {
 618			err = PTR_ERR(bh);
 619			bh = NULL;
 620			goto out;
 621		}
 622
 623		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 624				     sb->s_blocksize * 8, bh->b_data);
 625		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 626		if (err)
 627			goto out;
 628		brelse(bh);
 629	}
 630	bh = NULL;
 631
 632	/* Mark group tables in block bitmap */
 633	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 634		count = group_table_count[j];
 635		start = (&group_data[0].block_bitmap)[j];
 636		block = start;
 637		for (i = 1; i < flex_gd->count; i++) {
 638			block += group_table_count[j];
 639			if (block == (&group_data[i].block_bitmap)[j]) {
 640				count += group_table_count[j];
 641				continue;
 642			}
 643			err = set_flexbg_block_bitmap(sb, handle,
 644						flex_gd, start, count);
 645			if (err)
 646				goto out;
 647			count = group_table_count[j];
 648			start = (&group_data[i].block_bitmap)[j];
 649			block = start;
 650		}
 651
 652		if (count) {
 653			err = set_flexbg_block_bitmap(sb, handle,
 654						flex_gd, start, count);
 655			if (err)
 656				goto out;
 657		}
 658	}
 659
 660out:
 661	brelse(bh);
 662	err2 = ext4_journal_stop(handle);
 663	if (err2 && !err)
 664		err = err2;
 665
 666	return err;
 667}
 668
 669/*
 670 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 671 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 672 * calling this for the first time.  In a sparse filesystem it will be the
 673 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 674 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 675 */
 676static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 677				  unsigned *five, unsigned *seven)
 678{
 679	unsigned *min = three;
 680	int mult = 3;
 681	unsigned ret;
 682
 683	if (!ext4_has_feature_sparse_super(sb)) {
 
 684		ret = *min;
 685		*min += 1;
 686		return ret;
 687	}
 688
 689	if (*five < *min) {
 690		min = five;
 691		mult = 5;
 692	}
 693	if (*seven < *min) {
 694		min = seven;
 695		mult = 7;
 696	}
 697
 698	ret = *min;
 699	*min *= mult;
 700
 701	return ret;
 702}
 703
 704/*
 705 * Check that all of the backup GDT blocks are held in the primary GDT block.
 706 * It is assumed that they are stored in group order.  Returns the number of
 707 * groups in current filesystem that have BACKUPS, or -ve error code.
 708 */
 709static int verify_reserved_gdb(struct super_block *sb,
 710			       ext4_group_t end,
 711			       struct buffer_head *primary)
 712{
 713	const ext4_fsblk_t blk = primary->b_blocknr;
 714	unsigned three = 1;
 715	unsigned five = 5;
 716	unsigned seven = 7;
 717	unsigned grp;
 718	__le32 *p = (__le32 *)primary->b_data;
 719	int gdbackups = 0;
 720
 721	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 722		if (le32_to_cpu(*p++) !=
 723		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 724			ext4_warning(sb, "reserved GDT %llu"
 725				     " missing grp %d (%llu)",
 726				     blk, grp,
 727				     grp *
 728				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 729				     blk);
 730			return -EINVAL;
 731		}
 732		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 733			return -EFBIG;
 734	}
 735
 736	return gdbackups;
 737}
 738
 739/*
 740 * Called when we need to bring a reserved group descriptor table block into
 741 * use from the resize inode.  The primary copy of the new GDT block currently
 742 * is an indirect block (under the double indirect block in the resize inode).
 743 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 744 * block, in group order.  Even though we know all the block numbers we need,
 745 * we check to ensure that the resize inode has actually reserved these blocks.
 746 *
 747 * Don't need to update the block bitmaps because the blocks are still in use.
 748 *
 749 * We get all of the error cases out of the way, so that we are sure to not
 750 * fail once we start modifying the data on disk, because JBD has no rollback.
 751 */
 752static int add_new_gdb(handle_t *handle, struct inode *inode,
 753		       ext4_group_t group)
 754{
 755	struct super_block *sb = inode->i_sb;
 756	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 757	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 758	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 759	struct buffer_head **o_group_desc, **n_group_desc;
 760	struct buffer_head *dind;
 761	struct buffer_head *gdb_bh;
 762	int gdbackups;
 763	struct ext4_iloc iloc;
 764	__le32 *data;
 765	int err;
 766
 767	if (test_opt(sb, DEBUG))
 768		printk(KERN_DEBUG
 769		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 770		       gdb_num);
 771
 
 
 
 
 
 
 
 
 
 
 
 
 772	gdb_bh = sb_bread(sb, gdblock);
 773	if (!gdb_bh)
 774		return -EIO;
 775
 776	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 777	if (gdbackups < 0) {
 778		err = gdbackups;
 779		goto exit_bh;
 780	}
 781
 782	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 783	dind = sb_bread(sb, le32_to_cpu(*data));
 784	if (!dind) {
 785		err = -EIO;
 786		goto exit_bh;
 787	}
 788
 789	data = (__le32 *)dind->b_data;
 790	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 791		ext4_warning(sb, "new group %u GDT block %llu not reserved",
 792			     group, gdblock);
 793		err = -EINVAL;
 794		goto exit_dind;
 795	}
 796
 797	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 798	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 799	if (unlikely(err))
 800		goto exit_dind;
 801
 802	BUFFER_TRACE(gdb_bh, "get_write_access");
 803	err = ext4_journal_get_write_access(handle, gdb_bh);
 804	if (unlikely(err))
 805		goto exit_dind;
 806
 807	BUFFER_TRACE(dind, "get_write_access");
 808	err = ext4_journal_get_write_access(handle, dind);
 809	if (unlikely(err))
 810		ext4_std_error(sb, err);
 811
 812	/* ext4_reserve_inode_write() gets a reference on the iloc */
 813	err = ext4_reserve_inode_write(handle, inode, &iloc);
 814	if (unlikely(err))
 815		goto exit_dind;
 816
 817	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 818				     sizeof(struct buffer_head *),
 819				     GFP_NOFS);
 820	if (!n_group_desc) {
 821		err = -ENOMEM;
 822		ext4_warning(sb, "not enough memory for %lu groups",
 823			     gdb_num + 1);
 824		goto exit_inode;
 825	}
 826
 827	/*
 828	 * Finally, we have all of the possible failures behind us...
 829	 *
 830	 * Remove new GDT block from inode double-indirect block and clear out
 831	 * the new GDT block for use (which also "frees" the backup GDT blocks
 832	 * from the reserved inode).  We don't need to change the bitmaps for
 833	 * these blocks, because they are marked as in-use from being in the
 834	 * reserved inode, and will become GDT blocks (primary and backup).
 835	 */
 836	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 837	err = ext4_handle_dirty_metadata(handle, NULL, dind);
 838	if (unlikely(err)) {
 839		ext4_std_error(sb, err);
 840		goto exit_inode;
 841	}
 842	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 843	ext4_mark_iloc_dirty(handle, inode, &iloc);
 844	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 845	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 846	if (unlikely(err)) {
 847		ext4_std_error(sb, err);
 848		goto exit_inode;
 849	}
 850	brelse(dind);
 851
 852	o_group_desc = EXT4_SB(sb)->s_group_desc;
 853	memcpy(n_group_desc, o_group_desc,
 854	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 855	n_group_desc[gdb_num] = gdb_bh;
 856	EXT4_SB(sb)->s_group_desc = n_group_desc;
 857	EXT4_SB(sb)->s_gdb_count++;
 858	kvfree(o_group_desc);
 859
 860	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 861	err = ext4_handle_dirty_super(handle, sb);
 862	if (err)
 863		ext4_std_error(sb, err);
 864
 865	return err;
 866
 867exit_inode:
 868	kvfree(n_group_desc);
 869	brelse(iloc.bh);
 870exit_dind:
 871	brelse(dind);
 872exit_bh:
 873	brelse(gdb_bh);
 874
 875	ext4_debug("leaving with error %d\n", err);
 876	return err;
 877}
 878
 879/*
 880 * add_new_gdb_meta_bg is the sister of add_new_gdb.
 881 */
 882static int add_new_gdb_meta_bg(struct super_block *sb,
 883			       handle_t *handle, ext4_group_t group) {
 884	ext4_fsblk_t gdblock;
 885	struct buffer_head *gdb_bh;
 886	struct buffer_head **o_group_desc, **n_group_desc;
 887	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 888	int err;
 889
 890	gdblock = ext4_meta_bg_first_block_no(sb, group) +
 891		   ext4_bg_has_super(sb, group);
 892	gdb_bh = sb_bread(sb, gdblock);
 893	if (!gdb_bh)
 894		return -EIO;
 895	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 896				     sizeof(struct buffer_head *),
 897				     GFP_NOFS);
 898	if (!n_group_desc) {
 899		err = -ENOMEM;
 900		ext4_warning(sb, "not enough memory for %lu groups",
 901			     gdb_num + 1);
 902		return err;
 903	}
 904
 905	o_group_desc = EXT4_SB(sb)->s_group_desc;
 906	memcpy(n_group_desc, o_group_desc,
 907	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 908	n_group_desc[gdb_num] = gdb_bh;
 909	EXT4_SB(sb)->s_group_desc = n_group_desc;
 910	EXT4_SB(sb)->s_gdb_count++;
 911	kvfree(o_group_desc);
 912	BUFFER_TRACE(gdb_bh, "get_write_access");
 913	err = ext4_journal_get_write_access(handle, gdb_bh);
 914	if (unlikely(err))
 915		brelse(gdb_bh);
 916	return err;
 917}
 918
 919/*
 920 * Called when we are adding a new group which has a backup copy of each of
 921 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 922 * We need to add these reserved backup GDT blocks to the resize inode, so
 923 * that they are kept for future resizing and not allocated to files.
 924 *
 925 * Each reserved backup GDT block will go into a different indirect block.
 926 * The indirect blocks are actually the primary reserved GDT blocks,
 927 * so we know in advance what their block numbers are.  We only get the
 928 * double-indirect block to verify it is pointing to the primary reserved
 929 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 930 * backup GDT blocks are stored in their reserved primary GDT block.
 931 */
 932static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 933			      ext4_group_t group)
 934{
 935	struct super_block *sb = inode->i_sb;
 936	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 937	struct buffer_head **primary;
 938	struct buffer_head *dind;
 939	struct ext4_iloc iloc;
 940	ext4_fsblk_t blk;
 941	__le32 *data, *end;
 942	int gdbackups = 0;
 943	int res, i;
 944	int err;
 945
 946	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 947	if (!primary)
 948		return -ENOMEM;
 949
 950	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 951	dind = sb_bread(sb, le32_to_cpu(*data));
 952	if (!dind) {
 953		err = -EIO;
 954		goto exit_free;
 955	}
 956
 957	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 958	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 959					 EXT4_ADDR_PER_BLOCK(sb));
 960	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 961
 962	/* Get each reserved primary GDT block and verify it holds backups */
 963	for (res = 0; res < reserved_gdb; res++, blk++) {
 964		if (le32_to_cpu(*data) != blk) {
 965			ext4_warning(sb, "reserved block %llu"
 966				     " not at offset %ld",
 967				     blk,
 968				     (long)(data - (__le32 *)dind->b_data));
 969			err = -EINVAL;
 970			goto exit_bh;
 971		}
 972		primary[res] = sb_bread(sb, blk);
 973		if (!primary[res]) {
 974			err = -EIO;
 975			goto exit_bh;
 976		}
 977		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 978		if (gdbackups < 0) {
 979			brelse(primary[res]);
 980			err = gdbackups;
 981			goto exit_bh;
 982		}
 983		if (++data >= end)
 984			data = (__le32 *)dind->b_data;
 985	}
 986
 987	for (i = 0; i < reserved_gdb; i++) {
 988		BUFFER_TRACE(primary[i], "get_write_access");
 989		if ((err = ext4_journal_get_write_access(handle, primary[i])))
 990			goto exit_bh;
 991	}
 992
 993	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 994		goto exit_bh;
 995
 996	/*
 997	 * Finally we can add each of the reserved backup GDT blocks from
 998	 * the new group to its reserved primary GDT block.
 999	 */
1000	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1001	for (i = 0; i < reserved_gdb; i++) {
1002		int err2;
1003		data = (__le32 *)primary[i]->b_data;
1004		/* printk("reserving backup %lu[%u] = %lu\n",
1005		       primary[i]->b_blocknr, gdbackups,
1006		       blk + primary[i]->b_blocknr); */
1007		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1008		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1009		if (!err)
1010			err = err2;
1011	}
1012	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
1013	ext4_mark_iloc_dirty(handle, inode, &iloc);
1014
1015exit_bh:
1016	while (--res >= 0)
1017		brelse(primary[res]);
1018	brelse(dind);
1019
1020exit_free:
1021	kfree(primary);
1022
1023	return err;
1024}
1025
1026/*
1027 * Update the backup copies of the ext4 metadata.  These don't need to be part
1028 * of the main resize transaction, because e2fsck will re-write them if there
1029 * is a problem (basically only OOM will cause a problem).  However, we
1030 * _should_ update the backups if possible, in case the primary gets trashed
1031 * for some reason and we need to run e2fsck from a backup superblock.  The
1032 * important part is that the new block and inode counts are in the backup
1033 * superblocks, and the location of the new group metadata in the GDT backups.
1034 *
1035 * We do not need take the s_resize_lock for this, because these
1036 * blocks are not otherwise touched by the filesystem code when it is
1037 * mounted.  We don't need to worry about last changing from
1038 * sbi->s_groups_count, because the worst that can happen is that we
1039 * do not copy the full number of backups at this time.  The resize
1040 * which changed s_groups_count will backup again.
1041 */
1042static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1043			   int size, int meta_bg)
1044{
1045	struct ext4_sb_info *sbi = EXT4_SB(sb);
1046	ext4_group_t last;
1047	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1048	unsigned three = 1;
1049	unsigned five = 5;
1050	unsigned seven = 7;
1051	ext4_group_t group = 0;
1052	int rest = sb->s_blocksize - size;
1053	handle_t *handle;
1054	int err = 0, err2;
1055
1056	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1057	if (IS_ERR(handle)) {
1058		group = 1;
1059		err = PTR_ERR(handle);
1060		goto exit_err;
1061	}
1062
1063	if (meta_bg == 0) {
1064		group = ext4_list_backups(sb, &three, &five, &seven);
1065		last = sbi->s_groups_count;
1066	} else {
1067		group = ext4_get_group_number(sb, blk_off) + 1;
1068		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1069	}
1070
1071	while (group < sbi->s_groups_count) {
1072		struct buffer_head *bh;
1073		ext4_fsblk_t backup_block;
1074
1075		/* Out of journal space, and can't get more - abort - so sad */
1076		if (ext4_handle_valid(handle) &&
1077		    handle->h_buffer_credits == 0 &&
1078		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1079		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1080			break;
1081
1082		if (meta_bg == 0)
1083			backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1084		else
1085			backup_block = (ext4_group_first_block_no(sb, group) +
1086					ext4_bg_has_super(sb, group));
1087
1088		bh = sb_getblk(sb, backup_block);
1089		if (unlikely(!bh)) {
1090			err = -ENOMEM;
1091			break;
1092		}
1093		ext4_debug("update metadata backup %llu(+%llu)\n",
1094			   backup_block, backup_block -
1095			   ext4_group_first_block_no(sb, group));
1096		BUFFER_TRACE(bh, "get_write_access");
1097		if ((err = ext4_journal_get_write_access(handle, bh)))
1098			break;
1099		lock_buffer(bh);
1100		memcpy(bh->b_data, data, size);
1101		if (rest)
1102			memset(bh->b_data + size, 0, rest);
1103		set_buffer_uptodate(bh);
1104		unlock_buffer(bh);
1105		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1106		if (unlikely(err))
1107			ext4_std_error(sb, err);
1108		brelse(bh);
1109
1110		if (meta_bg == 0)
1111			group = ext4_list_backups(sb, &three, &five, &seven);
1112		else if (group == last)
1113			break;
1114		else
1115			group = last;
1116	}
1117	if ((err2 = ext4_journal_stop(handle)) && !err)
1118		err = err2;
1119
1120	/*
1121	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1122	 * late to revert the resize, we shouldn't fail just because of
1123	 * the backup copies (they are only needed in case of corruption).
1124	 *
1125	 * However, if we got here we have a journal problem too, so we
1126	 * can't really start a transaction to mark the superblock.
1127	 * Chicken out and just set the flag on the hope it will be written
1128	 * to disk, and if not - we will simply wait until next fsck.
1129	 */
1130exit_err:
1131	if (err) {
1132		ext4_warning(sb, "can't update backup for group %u (err %d), "
1133			     "forcing fsck on next reboot", group, err);
1134		sbi->s_mount_state &= ~EXT4_VALID_FS;
1135		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1136		mark_buffer_dirty(sbi->s_sbh);
1137	}
1138}
1139
1140/*
1141 * ext4_add_new_descs() adds @count group descriptor of groups
1142 * starting at @group
1143 *
1144 * @handle: journal handle
1145 * @sb: super block
1146 * @group: the group no. of the first group desc to be added
1147 * @resize_inode: the resize inode
1148 * @count: number of group descriptors to be added
1149 */
1150static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1151			      ext4_group_t group, struct inode *resize_inode,
1152			      ext4_group_t count)
1153{
1154	struct ext4_sb_info *sbi = EXT4_SB(sb);
1155	struct ext4_super_block *es = sbi->s_es;
1156	struct buffer_head *gdb_bh;
1157	int i, gdb_off, gdb_num, err = 0;
1158	int meta_bg;
1159
1160	meta_bg = ext4_has_feature_meta_bg(sb);
1161	for (i = 0; i < count; i++, group++) {
1162		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1163			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1164
1165		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1166		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1167
1168		/*
1169		 * We will only either add reserved group blocks to a backup group
1170		 * or remove reserved blocks for the first group in a new group block.
1171		 * Doing both would be mean more complex code, and sane people don't
1172		 * use non-sparse filesystems anymore.  This is already checked above.
1173		 */
1174		if (gdb_off) {
1175			gdb_bh = sbi->s_group_desc[gdb_num];
1176			BUFFER_TRACE(gdb_bh, "get_write_access");
1177			err = ext4_journal_get_write_access(handle, gdb_bh);
1178
1179			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1180				err = reserve_backup_gdb(handle, resize_inode, group);
1181		} else if (meta_bg != 0) {
1182			err = add_new_gdb_meta_bg(sb, handle, group);
1183		} else {
1184			err = add_new_gdb(handle, resize_inode, group);
1185		}
1186		if (err)
1187			break;
1188	}
1189	return err;
1190}
1191
1192static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1193{
1194	struct buffer_head *bh = sb_getblk(sb, block);
1195	if (unlikely(!bh))
1196		return NULL;
1197	if (!bh_uptodate_or_lock(bh)) {
1198		if (bh_submit_read(bh) < 0) {
1199			brelse(bh);
1200			return NULL;
1201		}
1202	}
1203
1204	return bh;
1205}
1206
1207static int ext4_set_bitmap_checksums(struct super_block *sb,
1208				     ext4_group_t group,
1209				     struct ext4_group_desc *gdp,
1210				     struct ext4_new_group_data *group_data)
1211{
1212	struct buffer_head *bh;
1213
1214	if (!ext4_has_metadata_csum(sb))
 
1215		return 0;
1216
1217	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1218	if (!bh)
1219		return -EIO;
1220	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1221				   EXT4_INODES_PER_GROUP(sb) / 8);
1222	brelse(bh);
1223
1224	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1225	if (!bh)
1226		return -EIO;
1227	ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1228	brelse(bh);
1229
1230	return 0;
1231}
1232
1233/*
1234 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1235 */
1236static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1237				struct ext4_new_flex_group_data *flex_gd)
1238{
1239	struct ext4_new_group_data	*group_data = flex_gd->groups;
1240	struct ext4_group_desc		*gdp;
1241	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1242	struct buffer_head		*gdb_bh;
1243	ext4_group_t			group;
1244	__u16				*bg_flags = flex_gd->bg_flags;
1245	int				i, gdb_off, gdb_num, err = 0;
1246	
1247
1248	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1249		group = group_data->group;
1250
1251		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1252		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1253
1254		/*
1255		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1256		 */
1257		gdb_bh = sbi->s_group_desc[gdb_num];
1258		/* Update group descriptor block for new group */
1259		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1260						 gdb_off * EXT4_DESC_SIZE(sb));
1261
1262		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1263		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1264		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1265		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1266		if (err) {
1267			ext4_std_error(sb, err);
1268			break;
1269		}
1270
1271		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1272		ext4_free_group_clusters_set(sb, gdp,
1273			EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1274		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1275		if (ext4_has_group_desc_csum(sb))
1276			ext4_itable_unused_set(sb, gdp,
1277					       EXT4_INODES_PER_GROUP(sb));
1278		gdp->bg_flags = cpu_to_le16(*bg_flags);
1279		ext4_group_desc_csum_set(sb, group, gdp);
1280
1281		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1282		if (unlikely(err)) {
1283			ext4_std_error(sb, err);
1284			break;
1285		}
1286
1287		/*
1288		 * We can allocate memory for mb_alloc based on the new group
1289		 * descriptor
1290		 */
1291		err = ext4_mb_add_groupinfo(sb, group, gdp);
1292		if (err)
1293			break;
1294	}
1295	return err;
1296}
1297
1298/*
1299 * ext4_update_super() updates the super block so that the newly added
1300 * groups can be seen by the filesystem.
1301 *
1302 * @sb: super block
1303 * @flex_gd: new added groups
1304 */
1305static void ext4_update_super(struct super_block *sb,
1306			     struct ext4_new_flex_group_data *flex_gd)
1307{
1308	ext4_fsblk_t blocks_count = 0;
1309	ext4_fsblk_t free_blocks = 0;
1310	ext4_fsblk_t reserved_blocks = 0;
1311	struct ext4_new_group_data *group_data = flex_gd->groups;
1312	struct ext4_sb_info *sbi = EXT4_SB(sb);
1313	struct ext4_super_block *es = sbi->s_es;
1314	int i;
1315
1316	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1317	/*
1318	 * Make the new blocks and inodes valid next.  We do this before
1319	 * increasing the group count so that once the group is enabled,
1320	 * all of its blocks and inodes are already valid.
1321	 *
1322	 * We always allocate group-by-group, then block-by-block or
1323	 * inode-by-inode within a group, so enabling these
1324	 * blocks/inodes before the group is live won't actually let us
1325	 * allocate the new space yet.
1326	 */
1327	for (i = 0; i < flex_gd->count; i++) {
1328		blocks_count += group_data[i].blocks_count;
1329		free_blocks += group_data[i].free_blocks_count;
1330	}
1331
1332	reserved_blocks = ext4_r_blocks_count(es) * 100;
1333	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1334	reserved_blocks *= blocks_count;
1335	do_div(reserved_blocks, 100);
1336
1337	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1338	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1339	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1340		     flex_gd->count);
1341	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1342		     flex_gd->count);
1343
1344	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1345	/*
1346	 * We need to protect s_groups_count against other CPUs seeing
1347	 * inconsistent state in the superblock.
1348	 *
1349	 * The precise rules we use are:
1350	 *
1351	 * * Writers must perform a smp_wmb() after updating all
1352	 *   dependent data and before modifying the groups count
1353	 *
1354	 * * Readers must perform an smp_rmb() after reading the groups
1355	 *   count and before reading any dependent data.
1356	 *
1357	 * NB. These rules can be relaxed when checking the group count
1358	 * while freeing data, as we can only allocate from a block
1359	 * group after serialising against the group count, and we can
1360	 * only then free after serialising in turn against that
1361	 * allocation.
1362	 */
1363	smp_wmb();
1364
1365	/* Update the global fs size fields */
1366	sbi->s_groups_count += flex_gd->count;
1367	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1368			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1369
1370	/* Update the reserved block counts only once the new group is
1371	 * active. */
1372	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1373				reserved_blocks);
1374
1375	/* Update the free space counts */
1376	percpu_counter_add(&sbi->s_freeclusters_counter,
1377			   EXT4_NUM_B2C(sbi, free_blocks));
1378	percpu_counter_add(&sbi->s_freeinodes_counter,
1379			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1380
1381	ext4_debug("free blocks count %llu",
1382		   percpu_counter_read(&sbi->s_freeclusters_counter));
1383	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
 
 
1384		ext4_group_t flex_group;
1385		flex_group = ext4_flex_group(sbi, group_data[0].group);
1386		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1387			     &sbi->s_flex_groups[flex_group].free_clusters);
1388		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1389			   &sbi->s_flex_groups[flex_group].free_inodes);
1390	}
1391
1392	/*
1393	 * Update the fs overhead information
1394	 */
1395	ext4_calculate_overhead(sb);
1396
1397	if (test_opt(sb, DEBUG))
1398		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1399		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1400		       blocks_count, free_blocks, reserved_blocks);
1401}
1402
1403/* Add a flex group to an fs. Ensure we handle all possible error conditions
1404 * _before_ we start modifying the filesystem, because we cannot abort the
1405 * transaction and not have it write the data to disk.
1406 */
1407static int ext4_flex_group_add(struct super_block *sb,
1408			       struct inode *resize_inode,
1409			       struct ext4_new_flex_group_data *flex_gd)
1410{
1411	struct ext4_sb_info *sbi = EXT4_SB(sb);
1412	struct ext4_super_block *es = sbi->s_es;
1413	ext4_fsblk_t o_blocks_count;
1414	ext4_grpblk_t last;
1415	ext4_group_t group;
1416	handle_t *handle;
1417	unsigned reserved_gdb;
1418	int err = 0, err2 = 0, credit;
1419
1420	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1421
1422	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1423	o_blocks_count = ext4_blocks_count(es);
1424	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1425	BUG_ON(last);
1426
1427	err = setup_new_flex_group_blocks(sb, flex_gd);
1428	if (err)
1429		goto exit;
1430	/*
1431	 * We will always be modifying at least the superblock and  GDT
1432	 * blocks.  If we are adding a group past the last current GDT block,
1433	 * we will also modify the inode and the dindirect block.  If we
1434	 * are adding a group with superblock/GDT backups  we will also
1435	 * modify each of the reserved GDT dindirect blocks.
1436	 */
1437	credit = 3;	/* sb, resize inode, resize inode dindirect */
1438	/* GDT blocks */
1439	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1440	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
1441	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1442	if (IS_ERR(handle)) {
1443		err = PTR_ERR(handle);
1444		goto exit;
1445	}
1446
1447	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1448	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1449	if (err)
1450		goto exit_journal;
1451
1452	group = flex_gd->groups[0].group;
1453	BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1454	err = ext4_add_new_descs(handle, sb, group,
1455				resize_inode, flex_gd->count);
1456	if (err)
1457		goto exit_journal;
1458
1459	err = ext4_setup_new_descs(handle, sb, flex_gd);
1460	if (err)
1461		goto exit_journal;
1462
1463	ext4_update_super(sb, flex_gd);
1464
1465	err = ext4_handle_dirty_super(handle, sb);
1466
1467exit_journal:
1468	err2 = ext4_journal_stop(handle);
1469	if (!err)
1470		err = err2;
1471
1472	if (!err) {
1473		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1474		int gdb_num_end = ((group + flex_gd->count - 1) /
1475				   EXT4_DESC_PER_BLOCK(sb));
1476		int meta_bg = ext4_has_feature_meta_bg(sb);
 
1477		sector_t old_gdb = 0;
1478
1479		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1480			       sizeof(struct ext4_super_block), 0);
1481		for (; gdb_num <= gdb_num_end; gdb_num++) {
1482			struct buffer_head *gdb_bh;
1483
1484			gdb_bh = sbi->s_group_desc[gdb_num];
1485			if (old_gdb == gdb_bh->b_blocknr)
1486				continue;
1487			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1488				       gdb_bh->b_size, meta_bg);
1489			old_gdb = gdb_bh->b_blocknr;
1490		}
1491	}
1492exit:
1493	return err;
1494}
1495
1496static int ext4_setup_next_flex_gd(struct super_block *sb,
1497				    struct ext4_new_flex_group_data *flex_gd,
1498				    ext4_fsblk_t n_blocks_count,
1499				    unsigned long flexbg_size)
1500{
1501	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1502	struct ext4_new_group_data *group_data = flex_gd->groups;
1503	ext4_fsblk_t o_blocks_count;
1504	ext4_group_t n_group;
1505	ext4_group_t group;
1506	ext4_group_t last_group;
1507	ext4_grpblk_t last;
1508	ext4_grpblk_t blocks_per_group;
1509	unsigned long i;
1510
1511	blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1512
1513	o_blocks_count = ext4_blocks_count(es);
1514
1515	if (o_blocks_count == n_blocks_count)
1516		return 0;
1517
1518	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1519	BUG_ON(last);
1520	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1521
1522	last_group = group | (flexbg_size - 1);
1523	if (last_group > n_group)
1524		last_group = n_group;
1525
1526	flex_gd->count = last_group - group + 1;
1527
1528	for (i = 0; i < flex_gd->count; i++) {
1529		int overhead;
1530
1531		group_data[i].group = group + i;
1532		group_data[i].blocks_count = blocks_per_group;
1533		overhead = ext4_group_overhead_blocks(sb, group + i);
1534		group_data[i].free_blocks_count = blocks_per_group - overhead;
1535		if (ext4_has_group_desc_csum(sb)) {
1536			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1537					       EXT4_BG_INODE_UNINIT;
1538			if (!test_opt(sb, INIT_INODE_TABLE))
1539				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1540		} else
1541			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1542	}
1543
1544	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1545		/* We need to initialize block bitmap of last group. */
1546		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1547
1548	if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1549		group_data[i - 1].blocks_count = last + 1;
1550		group_data[i - 1].free_blocks_count -= blocks_per_group-
1551					last - 1;
1552	}
1553
1554	return 1;
1555}
1556
1557/* Add group descriptor data to an existing or new group descriptor block.
1558 * Ensure we handle all possible error conditions _before_ we start modifying
1559 * the filesystem, because we cannot abort the transaction and not have it
1560 * write the data to disk.
1561 *
1562 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1563 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1564 *
1565 * We only need to hold the superblock lock while we are actually adding
1566 * in the new group's counts to the superblock.  Prior to that we have
1567 * not really "added" the group at all.  We re-check that we are still
1568 * adding in the last group in case things have changed since verifying.
1569 */
1570int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1571{
1572	struct ext4_new_flex_group_data flex_gd;
1573	struct ext4_sb_info *sbi = EXT4_SB(sb);
1574	struct ext4_super_block *es = sbi->s_es;
1575	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1576		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1577	struct inode *inode = NULL;
1578	int gdb_off;
1579	int err;
1580	__u16 bg_flags = 0;
1581
1582	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1583
1584	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
 
1585		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1586		return -EPERM;
1587	}
1588
1589	if (ext4_blocks_count(es) + input->blocks_count <
1590	    ext4_blocks_count(es)) {
1591		ext4_warning(sb, "blocks_count overflow");
1592		return -EINVAL;
1593	}
1594
1595	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1596	    le32_to_cpu(es->s_inodes_count)) {
1597		ext4_warning(sb, "inodes_count overflow");
1598		return -EINVAL;
1599	}
1600
1601	if (reserved_gdb || gdb_off == 0) {
1602		if (ext4_has_feature_resize_inode(sb) ||
1603		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
 
1604			ext4_warning(sb,
1605				     "No reserved GDT blocks, can't resize");
1606			return -EPERM;
1607		}
1608		inode = ext4_iget(sb, EXT4_RESIZE_INO);
1609		if (IS_ERR(inode)) {
1610			ext4_warning(sb, "Error opening resize inode");
1611			return PTR_ERR(inode);
1612		}
1613	}
1614
1615
1616	err = verify_group_input(sb, input);
1617	if (err)
1618		goto out;
1619
1620	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1621	if (err)
1622		goto out;
1623
1624	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1625	if (err)
1626		goto out;
1627
1628	flex_gd.count = 1;
1629	flex_gd.groups = input;
1630	flex_gd.bg_flags = &bg_flags;
1631	err = ext4_flex_group_add(sb, inode, &flex_gd);
1632out:
1633	iput(inode);
1634	return err;
1635} /* ext4_group_add */
1636
1637/*
1638 * extend a group without checking assuming that checking has been done.
1639 */
1640static int ext4_group_extend_no_check(struct super_block *sb,
1641				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1642{
1643	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1644	handle_t *handle;
1645	int err = 0, err2;
1646
1647	/* We will update the superblock, one block bitmap, and
1648	 * one group descriptor via ext4_group_add_blocks().
1649	 */
1650	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1651	if (IS_ERR(handle)) {
1652		err = PTR_ERR(handle);
1653		ext4_warning(sb, "error %d on journal start", err);
1654		return err;
1655	}
1656
1657	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1658	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1659	if (err) {
1660		ext4_warning(sb, "error %d on journal write access", err);
1661		goto errout;
1662	}
1663
1664	ext4_blocks_count_set(es, o_blocks_count + add);
1665	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1666	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1667		   o_blocks_count + add);
1668	/* We add the blocks to the bitmap and set the group need init bit */
1669	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1670	if (err)
1671		goto errout;
1672	ext4_handle_dirty_super(handle, sb);
1673	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1674		   o_blocks_count + add);
1675errout:
1676	err2 = ext4_journal_stop(handle);
1677	if (err2 && !err)
1678		err = err2;
1679
1680	if (!err) {
1681		if (test_opt(sb, DEBUG))
1682			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1683			       "blocks\n", ext4_blocks_count(es));
1684		update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1685			       (char *)es, sizeof(struct ext4_super_block), 0);
1686	}
1687	return err;
1688}
1689
1690/*
1691 * Extend the filesystem to the new number of blocks specified.  This entry
1692 * point is only used to extend the current filesystem to the end of the last
1693 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1694 * for emergencies (because it has no dependencies on reserved blocks).
1695 *
1696 * If we _really_ wanted, we could use default values to call ext4_group_add()
1697 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1698 * GDT blocks are reserved to grow to the desired size.
1699 */
1700int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1701		      ext4_fsblk_t n_blocks_count)
1702{
1703	ext4_fsblk_t o_blocks_count;
1704	ext4_grpblk_t last;
1705	ext4_grpblk_t add;
1706	struct buffer_head *bh;
1707	int err;
1708	ext4_group_t group;
1709
1710	o_blocks_count = ext4_blocks_count(es);
1711
1712	if (test_opt(sb, DEBUG))
1713		ext4_msg(sb, KERN_DEBUG,
1714			 "extending last group from %llu to %llu blocks",
1715			 o_blocks_count, n_blocks_count);
1716
1717	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1718		return 0;
1719
1720	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1721		ext4_msg(sb, KERN_ERR,
1722			 "filesystem too large to resize to %llu blocks safely",
1723			 n_blocks_count);
1724		if (sizeof(sector_t) < 8)
1725			ext4_warning(sb, "CONFIG_LBDAF not enabled");
1726		return -EINVAL;
1727	}
1728
1729	if (n_blocks_count < o_blocks_count) {
1730		ext4_warning(sb, "can't shrink FS - resize aborted");
1731		return -EINVAL;
1732	}
1733
1734	/* Handle the remaining blocks in the last group only. */
1735	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1736
1737	if (last == 0) {
1738		ext4_warning(sb, "need to use ext2online to resize further");
1739		return -EPERM;
1740	}
1741
1742	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1743
1744	if (o_blocks_count + add < o_blocks_count) {
1745		ext4_warning(sb, "blocks_count overflow");
1746		return -EINVAL;
1747	}
1748
1749	if (o_blocks_count + add > n_blocks_count)
1750		add = n_blocks_count - o_blocks_count;
1751
1752	if (o_blocks_count + add < n_blocks_count)
1753		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1754			     o_blocks_count + add, add);
1755
1756	/* See if the device is actually as big as what was requested */
1757	bh = sb_bread(sb, o_blocks_count + add - 1);
1758	if (!bh) {
1759		ext4_warning(sb, "can't read last block, resize aborted");
1760		return -ENOSPC;
1761	}
1762	brelse(bh);
1763
1764	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1765	return err;
1766} /* ext4_group_extend */
1767
1768
1769static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1770{
1771	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1772}
1773
1774/*
1775 * Release the resize inode and drop the resize_inode feature if there
1776 * are no more reserved gdt blocks, and then convert the file system
1777 * to enable meta_bg
1778 */
1779static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1780{
1781	handle_t *handle;
1782	struct ext4_sb_info *sbi = EXT4_SB(sb);
1783	struct ext4_super_block *es = sbi->s_es;
1784	struct ext4_inode_info *ei = EXT4_I(inode);
1785	ext4_fsblk_t nr;
1786	int i, ret, err = 0;
1787	int credits = 1;
1788
1789	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1790	if (inode) {
1791		if (es->s_reserved_gdt_blocks) {
1792			ext4_error(sb, "Unexpected non-zero "
1793				   "s_reserved_gdt_blocks");
1794			return -EPERM;
1795		}
1796
1797		/* Do a quick sanity check of the resize inode */
1798		if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
1799			goto invalid_resize_inode;
1800		for (i = 0; i < EXT4_N_BLOCKS; i++) {
1801			if (i == EXT4_DIND_BLOCK) {
1802				if (ei->i_data[i])
1803					continue;
1804				else
1805					goto invalid_resize_inode;
1806			}
1807			if (ei->i_data[i])
1808				goto invalid_resize_inode;
1809		}
1810		credits += 3;	/* block bitmap, bg descriptor, resize inode */
1811	}
1812
1813	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1814	if (IS_ERR(handle))
1815		return PTR_ERR(handle);
1816
1817	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1818	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1819	if (err)
1820		goto errout;
1821
1822	ext4_clear_feature_resize_inode(sb);
1823	ext4_set_feature_meta_bg(sb);
1824	sbi->s_es->s_first_meta_bg =
1825		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1826
1827	err = ext4_handle_dirty_super(handle, sb);
1828	if (err) {
1829		ext4_std_error(sb, err);
1830		goto errout;
1831	}
1832
1833	if (inode) {
1834		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1835		ext4_free_blocks(handle, inode, NULL, nr, 1,
1836				 EXT4_FREE_BLOCKS_METADATA |
1837				 EXT4_FREE_BLOCKS_FORGET);
1838		ei->i_data[EXT4_DIND_BLOCK] = 0;
1839		inode->i_blocks = 0;
1840
1841		err = ext4_mark_inode_dirty(handle, inode);
1842		if (err)
1843			ext4_std_error(sb, err);
1844	}
1845
1846errout:
1847	ret = ext4_journal_stop(handle);
1848	if (!err)
1849		err = ret;
1850	return ret;
1851
1852invalid_resize_inode:
1853	ext4_error(sb, "corrupted/inconsistent resize inode");
1854	return -EINVAL;
1855}
1856
1857/*
1858 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1859 *
1860 * @sb: super block of the fs to be resized
1861 * @n_blocks_count: the number of blocks resides in the resized fs
1862 */
1863int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1864{
1865	struct ext4_new_flex_group_data *flex_gd = NULL;
1866	struct ext4_sb_info *sbi = EXT4_SB(sb);
1867	struct ext4_super_block *es = sbi->s_es;
1868	struct buffer_head *bh;
1869	struct inode *resize_inode = NULL;
1870	ext4_grpblk_t add, offset;
1871	unsigned long n_desc_blocks;
1872	unsigned long o_desc_blocks;
1873	ext4_group_t o_group;
1874	ext4_group_t n_group;
1875	ext4_fsblk_t o_blocks_count;
1876	ext4_fsblk_t n_blocks_count_retry = 0;
1877	unsigned long last_update_time = 0;
1878	int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1879	int meta_bg;
1880
1881	/* See if the device is actually as big as what was requested */
1882	bh = sb_bread(sb, n_blocks_count - 1);
1883	if (!bh) {
1884		ext4_warning(sb, "can't read last block, resize aborted");
1885		return -ENOSPC;
1886	}
1887	brelse(bh);
1888
1889retry:
1890	o_blocks_count = ext4_blocks_count(es);
1891
1892	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1893		 "to %llu blocks", o_blocks_count, n_blocks_count);
1894
1895	if (n_blocks_count < o_blocks_count) {
1896		/* On-line shrinking not supported */
1897		ext4_warning(sb, "can't shrink FS - resize aborted");
1898		return -EINVAL;
1899	}
1900
1901	if (n_blocks_count == o_blocks_count)
1902		/* Nothing need to do */
1903		return 0;
1904
1905	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1906	if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1907		ext4_warning(sb, "resize would cause inodes_count overflow");
1908		return -EINVAL;
1909	}
1910	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1911
1912	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1913	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1914
1915	meta_bg = ext4_has_feature_meta_bg(sb);
1916
1917	if (ext4_has_feature_resize_inode(sb)) {
1918		if (meta_bg) {
1919			ext4_error(sb, "resize_inode and meta_bg enabled "
1920				   "simultaneously");
1921			return -EINVAL;
1922		}
1923		if (n_desc_blocks > o_desc_blocks +
1924		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
1925			n_blocks_count_retry = n_blocks_count;
1926			n_desc_blocks = o_desc_blocks +
1927				le16_to_cpu(es->s_reserved_gdt_blocks);
1928			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1929			n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
1930			n_group--; /* set to last group number */
1931		}
1932
1933		if (!resize_inode)
1934			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1935		if (IS_ERR(resize_inode)) {
1936			ext4_warning(sb, "Error opening resize inode");
1937			return PTR_ERR(resize_inode);
1938		}
1939	}
1940
1941	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1942		err = ext4_convert_meta_bg(sb, resize_inode);
1943		if (err)
1944			goto out;
1945		if (resize_inode) {
1946			iput(resize_inode);
1947			resize_inode = NULL;
1948		}
1949		if (n_blocks_count_retry) {
1950			n_blocks_count = n_blocks_count_retry;
1951			n_blocks_count_retry = 0;
1952			goto retry;
1953		}
1954	}
1955
1956	/* extend the last group */
1957	if (n_group == o_group)
1958		add = n_blocks_count - o_blocks_count;
1959	else
1960		add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1961	if (add > 0) {
1962		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1963		if (err)
1964			goto out;
1965	}
1966
1967	if (ext4_blocks_count(es) == n_blocks_count)
1968		goto out;
1969
1970	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1971	if (err)
1972		return err;
1973
1974	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1975	if (err)
1976		goto out;
1977
1978	flex_gd = alloc_flex_gd(flexbg_size);
1979	if (flex_gd == NULL) {
1980		err = -ENOMEM;
1981		goto out;
1982	}
1983
1984	/* Add flex groups. Note that a regular group is a
1985	 * flex group with 1 group.
1986	 */
1987	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1988					      flexbg_size)) {
1989		if (jiffies - last_update_time > HZ * 10) {
1990			if (last_update_time)
1991				ext4_msg(sb, KERN_INFO,
1992					 "resized to %llu blocks",
1993					 ext4_blocks_count(es));
1994			last_update_time = jiffies;
1995		}
1996		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1997			break;
1998		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1999		if (unlikely(err))
2000			break;
2001	}
2002
2003	if (!err && n_blocks_count_retry) {
2004		n_blocks_count = n_blocks_count_retry;
2005		n_blocks_count_retry = 0;
2006		free_flex_gd(flex_gd);
2007		flex_gd = NULL;
2008		goto retry;
2009	}
2010
2011out:
2012	if (flex_gd)
2013		free_flex_gd(flex_gd);
2014	if (resize_inode != NULL)
2015		iput(resize_inode);
2016	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2017	return err;
2018}