1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext4/resize.c
   4 *
   5 * Support for resizing an ext4 filesystem while it is mounted.
   6 *
   7 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8 *
   9 * This could probably be made into a module, because it is not often in use.
  10 */
  11
  12
  13#define EXT4FS_DEBUG
  14
  15#include <linux/errno.h>
  16#include <linux/slab.h>
  17
  18#include "ext4_jbd2.h"
  19
  20int ext4_resize_begin(struct super_block *sb)
  21{
  22	int ret = 0;
  23
  24	if (!capable(CAP_SYS_RESOURCE))
  25		return -EPERM;
  26
  27	/*
  28	 * If we are not using the primary superblock/GDT copy don't resize,
  29         * because the user tools have no way of handling this.  Probably a
  30         * bad time to do it anyways.
  31         */
  32	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
  33	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  34		ext4_warning(sb, "won't resize using backup superblock at %llu",
  35			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  36		return -EPERM;
  37	}
  38
  39	/*
  40	 * We are not allowed to do online-resizing on a filesystem mounted
  41	 * with error, because it can destroy the filesystem easily.
  42	 */
  43	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  44		ext4_warning(sb, "There are errors in the filesystem, "
  45			     "so online resizing is not allowed");
  46		return -EPERM;
  47	}
  48
  49	if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  50				  &EXT4_SB(sb)->s_ext4_flags))
  51		ret = -EBUSY;
  52
  53	return ret;
  54}
  55
  56void ext4_resize_end(struct super_block *sb)
  57{
  58	clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
  59	smp_mb__after_atomic();
  60}
  61
  62static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  63					     ext4_group_t group) {
  64	return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  65	       EXT4_DESC_PER_BLOCK_BITS(sb);
  66}
  67
  68static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  69					     ext4_group_t group) {
  70	group = ext4_meta_bg_first_group(sb, group);
  71	return ext4_group_first_block_no(sb, group);
  72}
  73
  74static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  75						ext4_group_t group) {
  76	ext4_grpblk_t overhead;
  77	overhead = ext4_bg_num_gdb(sb, group);
  78	if (ext4_bg_has_super(sb, group))
  79		overhead += 1 +
  80			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  81	return overhead;
  82}
  83
  84#define outside(b, first, last)	((b) < (first) || (b) >= (last))
  85#define inside(b, first, last)	((b) >= (first) && (b) < (last))
  86
  87static int verify_group_input(struct super_block *sb,
  88			      struct ext4_new_group_data *input)
  89{
  90	struct ext4_sb_info *sbi = EXT4_SB(sb);
  91	struct ext4_super_block *es = sbi->s_es;
  92	ext4_fsblk_t start = ext4_blocks_count(es);
  93	ext4_fsblk_t end = start + input->blocks_count;
  94	ext4_group_t group = input->group;
  95	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  96	unsigned overhead;
  97	ext4_fsblk_t metaend;
  98	struct buffer_head *bh = NULL;
  99	ext4_grpblk_t free_blocks_count, offset;
 100	int err = -EINVAL;
 101
 102	if (group != sbi->s_groups_count) {
 103		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 104			     input->group, sbi->s_groups_count);
 105		return -EINVAL;
 106	}
 107
 108	overhead = ext4_group_overhead_blocks(sb, group);
 109	metaend = start + overhead;
 110	input->free_clusters_count = free_blocks_count =
 111		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 112
 113	if (test_opt(sb, DEBUG))
 114		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 115		       "(%d free, %u reserved)\n",
 116		       ext4_bg_has_super(sb, input->group) ? "normal" :
 117		       "no-super", input->group, input->blocks_count,
 118		       free_blocks_count, input->reserved_blocks);
 119
 120	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 121	if (offset != 0)
 122			ext4_warning(sb, "Last group not full");
 123	else if (input->reserved_blocks > input->blocks_count / 5)
 124		ext4_warning(sb, "Reserved blocks too high (%u)",
 125			     input->reserved_blocks);
 126	else if (free_blocks_count < 0)
 127		ext4_warning(sb, "Bad blocks count %u",
 128			     input->blocks_count);
 129	else if (!(bh = sb_bread(sb, end - 1)))
 130		ext4_warning(sb, "Cannot read last block (%llu)",
 131			     end - 1);
 132	else if (outside(input->block_bitmap, start, end))
 133		ext4_warning(sb, "Block bitmap not in group (block %llu)",
 134			     (unsigned long long)input->block_bitmap);
 135	else if (outside(input->inode_bitmap, start, end))
 136		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 137			     (unsigned long long)input->inode_bitmap);
 138	else if (outside(input->inode_table, start, end) ||
 139		 outside(itend - 1, start, end))
 140		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 141			     (unsigned long long)input->inode_table, itend - 1);
 142	else if (input->inode_bitmap == input->block_bitmap)
 143		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 144			     (unsigned long long)input->block_bitmap);
 145	else if (inside(input->block_bitmap, input->inode_table, itend))
 146		ext4_warning(sb, "Block bitmap (%llu) in inode table "
 147			     "(%llu-%llu)",
 148			     (unsigned long long)input->block_bitmap,
 149			     (unsigned long long)input->inode_table, itend - 1);
 150	else if (inside(input->inode_bitmap, input->inode_table, itend))
 151		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 152			     "(%llu-%llu)",
 153			     (unsigned long long)input->inode_bitmap,
 154			     (unsigned long long)input->inode_table, itend - 1);
 155	else if (inside(input->block_bitmap, start, metaend))
 156		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 157			     (unsigned long long)input->block_bitmap,
 158			     start, metaend - 1);
 159	else if (inside(input->inode_bitmap, start, metaend))
 160		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 161			     (unsigned long long)input->inode_bitmap,
 162			     start, metaend - 1);
 163	else if (inside(input->inode_table, start, metaend) ||
 164		 inside(itend - 1, start, metaend))
 165		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 166			     "(%llu-%llu)",
 167			     (unsigned long long)input->inode_table,
 168			     itend - 1, start, metaend - 1);
 169	else
 170		err = 0;
 171	brelse(bh);
 172
 173	return err;
 174}
 175
 176/*
 177 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 178 * group each time.
 179 */
 180struct ext4_new_flex_group_data {
 181	struct ext4_new_group_data *groups;	/* new_group_data for groups
 182						   in the flex group */
 183	__u16 *bg_flags;			/* block group flags of groups
 184						   in @groups */
 185	ext4_group_t count;			/* number of groups in @groups
 186						 */
 187};
 188
 189/*
 190 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 191 * @flexbg_size.
 192 *
 193 * Returns NULL on failure otherwise address of the allocated structure.
 194 */
 195static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 196{
 197	struct ext4_new_flex_group_data *flex_gd;
 198
 199	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 200	if (flex_gd == NULL)
 201		goto out3;
 202
 203	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 204		goto out2;
 205	flex_gd->count = flexbg_size;
 206
 207	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 208				  flexbg_size, GFP_NOFS);
 209	if (flex_gd->groups == NULL)
 210		goto out2;
 211
 212	flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 213	if (flex_gd->bg_flags == NULL)
 214		goto out1;
 215
 216	return flex_gd;
 217
 218out1:
 219	kfree(flex_gd->groups);
 220out2:
 221	kfree(flex_gd);
 222out3:
 223	return NULL;
 224}
 225
 226static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 227{
 228	kfree(flex_gd->bg_flags);
 229	kfree(flex_gd->groups);
 230	kfree(flex_gd);
 231}
 232
 233/*
 234 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 235 * and inode tables for a flex group.
 236 *
 237 * This function is used by 64bit-resize.  Note that this function allocates
 238 * group tables from the 1st group of groups contained by @flexgd, which may
 239 * be a partial of a flex group.
 240 *
 241 * @sb: super block of fs to which the groups belongs
 242 *
 243 * Returns 0 on a successful allocation of the metadata blocks in the
 244 * block group.
 245 */
 246static int ext4_alloc_group_tables(struct super_block *sb,
 247				struct ext4_new_flex_group_data *flex_gd,
 248				int flexbg_size)
 249{
 250	struct ext4_new_group_data *group_data = flex_gd->groups;
 251	ext4_fsblk_t start_blk;
 252	ext4_fsblk_t last_blk;
 253	ext4_group_t src_group;
 254	ext4_group_t bb_index = 0;
 255	ext4_group_t ib_index = 0;
 256	ext4_group_t it_index = 0;
 257	ext4_group_t group;
 258	ext4_group_t last_group;
 259	unsigned overhead;
 260	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 261	int i;
 262
 263	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 264
 265	src_group = group_data[0].group;
 266	last_group  = src_group + flex_gd->count - 1;
 267
 268	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 269	       (last_group & ~(flexbg_size - 1))));
 270next_group:
 271	group = group_data[0].group;
 272	if (src_group >= group_data[0].group + flex_gd->count)
 273		return -ENOSPC;
 274	start_blk = ext4_group_first_block_no(sb, src_group);
 275	last_blk = start_blk + group_data[src_group - group].blocks_count;
 276
 277	overhead = ext4_group_overhead_blocks(sb, src_group);
 278
 279	start_blk += overhead;
 280
 281	/* We collect contiguous blocks as much as possible. */
 282	src_group++;
 283	for (; src_group <= last_group; src_group++) {
 284		overhead = ext4_group_overhead_blocks(sb, src_group);
 285		if (overhead == 0)
 286			last_blk += group_data[src_group - group].blocks_count;
 287		else
 288			break;
 289	}
 290
 291	/* Allocate block bitmaps */
 292	for (; bb_index < flex_gd->count; bb_index++) {
 293		if (start_blk >= last_blk)
 294			goto next_group;
 295		group_data[bb_index].block_bitmap = start_blk++;
 296		group = ext4_get_group_number(sb, start_blk - 1);
 297		group -= group_data[0].group;
 298		group_data[group].mdata_blocks++;
 299		flex_gd->bg_flags[group] &= uninit_mask;
 300	}
 301
 302	/* Allocate inode bitmaps */
 303	for (; ib_index < flex_gd->count; ib_index++) {
 304		if (start_blk >= last_blk)
 305			goto next_group;
 306		group_data[ib_index].inode_bitmap = start_blk++;
 307		group = ext4_get_group_number(sb, start_blk - 1);
 308		group -= group_data[0].group;
 309		group_data[group].mdata_blocks++;
 310		flex_gd->bg_flags[group] &= uninit_mask;
 311	}
 312
 313	/* Allocate inode tables */
 314	for (; it_index < flex_gd->count; it_index++) {
 315		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 316		ext4_fsblk_t next_group_start;
 317
 318		if (start_blk + itb > last_blk)
 319			goto next_group;
 320		group_data[it_index].inode_table = start_blk;
 321		group = ext4_get_group_number(sb, start_blk);
 322		next_group_start = ext4_group_first_block_no(sb, group + 1);
 323		group -= group_data[0].group;
 324
 325		if (start_blk + itb > next_group_start) {
 326			flex_gd->bg_flags[group + 1] &= uninit_mask;
 327			overhead = start_blk + itb - next_group_start;
 328			group_data[group + 1].mdata_blocks += overhead;
 329			itb -= overhead;
 330		}
 331
 332		group_data[group].mdata_blocks += itb;
 333		flex_gd->bg_flags[group] &= uninit_mask;
 334		start_blk += EXT4_SB(sb)->s_itb_per_group;
 335	}
 336
 337	/* Update free clusters count to exclude metadata blocks */
 338	for (i = 0; i < flex_gd->count; i++) {
 339		group_data[i].free_clusters_count -=
 340				EXT4_NUM_B2C(EXT4_SB(sb),
 341					     group_data[i].mdata_blocks);
 342	}
 343
 344	if (test_opt(sb, DEBUG)) {
 345		int i;
 346		group = group_data[0].group;
 347
 348		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 349		       "%d groups, flexbg size is %d:\n", flex_gd->count,
 350		       flexbg_size);
 351
 352		for (i = 0; i < flex_gd->count; i++) {
 353			ext4_debug(
 354			       "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 355			       ext4_bg_has_super(sb, group + i) ? "normal" :
 356			       "no-super", group + i,
 357			       group_data[i].blocks_count,
 358			       group_data[i].free_clusters_count,
 359			       group_data[i].mdata_blocks);
 360		}
 361	}
 362	return 0;
 363}
 364
 365static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 366				  ext4_fsblk_t blk)
 367{
 368	struct buffer_head *bh;
 369	int err;
 370
 371	bh = sb_getblk(sb, blk);
 372	if (unlikely(!bh))
 373		return ERR_PTR(-ENOMEM);
 374	BUFFER_TRACE(bh, "get_write_access");
 375	if ((err = ext4_journal_get_write_access(handle, bh))) {
 376		brelse(bh);
 377		bh = ERR_PTR(err);
 378	} else {
 379		memset(bh->b_data, 0, sb->s_blocksize);
 380		set_buffer_uptodate(bh);
 381	}
 382
 383	return bh;
 384}
 385
 386/*
 387 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 388 * If that fails, restart the transaction & regain write access for the
 389 * buffer head which is used for block_bitmap modifications.
 390 */
 391static int extend_or_restart_transaction(handle_t *handle, int thresh)
 392{
 393	int err;
 394
 395	if (ext4_handle_has_enough_credits(handle, thresh))
 396		return 0;
 397
 398	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 399	if (err < 0)
 400		return err;
 401	if (err) {
 402		err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 403		if (err)
 404			return err;
 405	}
 406
 407	return 0;
 408}
 409
 410/*
 411 * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 412 *
 413 * Helper function for ext4_setup_new_group_blocks() which set .
 414 *
 415 * @sb: super block
 416 * @handle: journal handle
 417 * @flex_gd: flex group data
 418 */
 419static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 420			struct ext4_new_flex_group_data *flex_gd,
 421			ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 422{
 423	struct ext4_sb_info *sbi = EXT4_SB(sb);
 424	ext4_group_t count = last_cluster - first_cluster + 1;
 425	ext4_group_t count2;
 426
 427	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 428		   last_cluster);
 429	for (count2 = count; count > 0;
 430	     count -= count2, first_cluster += count2) {
 431		ext4_fsblk_t start;
 432		struct buffer_head *bh;
 433		ext4_group_t group;
 434		int err;
 435
 436		group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 437		start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 438		group -= flex_gd->groups[0].group;
 439
 440		count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 441		if (count2 > count)
 442			count2 = count;
 443
 444		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 445			BUG_ON(flex_gd->count > 1);
 446			continue;
 447		}
 448
 449		err = extend_or_restart_transaction(handle, 1);
 450		if (err)
 451			return err;
 452
 453		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 454		if (unlikely(!bh))
 455			return -ENOMEM;
 456
 457		BUFFER_TRACE(bh, "get_write_access");
 458		err = ext4_journal_get_write_access(handle, bh);
 459		if (err)
 460			return err;
 461		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 462			   first_cluster, first_cluster - start, count2);
 463		ext4_set_bits(bh->b_data, first_cluster - start, count2);
 464
 465		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 466		if (unlikely(err))
 467			return err;
 468		brelse(bh);
 469	}
 470
 471	return 0;
 472}
 473
 474/*
 475 * Set up the block and inode bitmaps, and the inode table for the new groups.
 476 * This doesn't need to be part of the main transaction, since we are only
 477 * changing blocks outside the actual filesystem.  We still do journaling to
 478 * ensure the recovery is correct in case of a failure just after resize.
 479 * If any part of this fails, we simply abort the resize.
 480 *
 481 * setup_new_flex_group_blocks handles a flex group as follow:
 482 *  1. copy super block and GDT, and initialize group tables if necessary.
 483 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 484 *     super block and GDT.
 485 *  2. allocate group tables in block bitmaps, that is, set bits in block
 486 *     bitmap for blocks taken by group tables.
 487 */
 488static int setup_new_flex_group_blocks(struct super_block *sb,
 489				struct ext4_new_flex_group_data *flex_gd)
 490{
 491	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 492	ext4_fsblk_t start;
 493	ext4_fsblk_t block;
 494	struct ext4_sb_info *sbi = EXT4_SB(sb);
 495	struct ext4_super_block *es = sbi->s_es;
 496	struct ext4_new_group_data *group_data = flex_gd->groups;
 497	__u16 *bg_flags = flex_gd->bg_flags;
 498	handle_t *handle;
 499	ext4_group_t group, count;
 500	struct buffer_head *bh = NULL;
 501	int reserved_gdb, i, j, err = 0, err2;
 502	int meta_bg;
 503
 504	BUG_ON(!flex_gd->count || !group_data ||
 505	       group_data[0].group != sbi->s_groups_count);
 506
 507	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 508	meta_bg = ext4_has_feature_meta_bg(sb);
 509
 510	/* This transaction may be extended/restarted along the way */
 511	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 512	if (IS_ERR(handle))
 513		return PTR_ERR(handle);
 514
 515	group = group_data[0].group;
 516	for (i = 0; i < flex_gd->count; i++, group++) {
 517		unsigned long gdblocks;
 518		ext4_grpblk_t overhead;
 519
 520		gdblocks = ext4_bg_num_gdb(sb, group);
 521		start = ext4_group_first_block_no(sb, group);
 522
 523		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 524			goto handle_itb;
 525
 526		if (meta_bg == 1) {
 527			ext4_group_t first_group;
 528			first_group = ext4_meta_bg_first_group(sb, group);
 529			if (first_group != group + 1 &&
 530			    first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 531				goto handle_itb;
 532		}
 533
 534		block = start + ext4_bg_has_super(sb, group);
 535		/* Copy all of the GDT blocks into the backup in this group */
 536		for (j = 0; j < gdblocks; j++, block++) {
 537			struct buffer_head *gdb;
 538
 539			ext4_debug("update backup group %#04llx\n", block);
 540			err = extend_or_restart_transaction(handle, 1);
 541			if (err)
 542				goto out;
 543
 544			gdb = sb_getblk(sb, block);
 545			if (unlikely(!gdb)) {
 546				err = -ENOMEM;
 547				goto out;
 548			}
 549
 550			BUFFER_TRACE(gdb, "get_write_access");
 551			err = ext4_journal_get_write_access(handle, gdb);
 552			if (err) {
 553				brelse(gdb);
 554				goto out;
 555			}
 556			memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 557			       gdb->b_size);
 558			set_buffer_uptodate(gdb);
 559
 560			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 561			if (unlikely(err)) {
 562				brelse(gdb);
 563				goto out;
 564			}
 565			brelse(gdb);
 566		}
 567
 568		/* Zero out all of the reserved backup group descriptor
 569		 * table blocks
 570		 */
 571		if (ext4_bg_has_super(sb, group)) {
 572			err = sb_issue_zeroout(sb, gdblocks + start + 1,
 573					reserved_gdb, GFP_NOFS);
 574			if (err)
 575				goto out;
 576		}
 577
 578handle_itb:
 579		/* Initialize group tables of the grop @group */
 580		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 581			goto handle_bb;
 582
 583		/* Zero out all of the inode table blocks */
 584		block = group_data[i].inode_table;
 585		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 586			   block, sbi->s_itb_per_group);
 587		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 588				       GFP_NOFS);
 589		if (err)
 590			goto out;
 591
 592handle_bb:
 593		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 594			goto handle_ib;
 595
 596		/* Initialize block bitmap of the @group */
 597		block = group_data[i].block_bitmap;
 598		err = extend_or_restart_transaction(handle, 1);
 599		if (err)
 600			goto out;
 601
 602		bh = bclean(handle, sb, block);
 603		if (IS_ERR(bh)) {
 604			err = PTR_ERR(bh);
 605			bh = NULL;
 606			goto out;
 607		}
 608		overhead = ext4_group_overhead_blocks(sb, group);
 609		if (overhead != 0) {
 610			ext4_debug("mark backup superblock %#04llx (+0)\n",
 611				   start);
 612			ext4_set_bits(bh->b_data, 0,
 613				      EXT4_NUM_B2C(sbi, overhead));
 614		}
 615		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 616				     sb->s_blocksize * 8, bh->b_data);
 617		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 618		if (err)
 619			goto out;
 620		brelse(bh);
 621
 622handle_ib:
 623		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 624			continue;
 625
 626		/* Initialize inode bitmap of the @group */
 627		block = group_data[i].inode_bitmap;
 628		err = extend_or_restart_transaction(handle, 1);
 629		if (err)
 630			goto out;
 631		/* Mark unused entries in inode bitmap used */
 632		bh = bclean(handle, sb, block);
 633		if (IS_ERR(bh)) {
 634			err = PTR_ERR(bh);
 635			bh = NULL;
 636			goto out;
 637		}
 638
 639		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 640				     sb->s_blocksize * 8, bh->b_data);
 641		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 642		if (err)
 643			goto out;
 644		brelse(bh);
 645	}
 646	bh = NULL;
 647
 648	/* Mark group tables in block bitmap */
 649	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 650		count = group_table_count[j];
 651		start = (&group_data[0].block_bitmap)[j];
 652		block = start;
 653		for (i = 1; i < flex_gd->count; i++) {
 654			block += group_table_count[j];
 655			if (block == (&group_data[i].block_bitmap)[j]) {
 656				count += group_table_count[j];
 657				continue;
 658			}
 659			err = set_flexbg_block_bitmap(sb, handle,
 660						      flex_gd,
 661						      EXT4_B2C(sbi, start),
 662						      EXT4_B2C(sbi,
 663							       start + count
 664							       - 1));
 665			if (err)
 666				goto out;
 667			count = group_table_count[j];
 668			start = (&group_data[i].block_bitmap)[j];
 669			block = start;
 670		}
 671
 672		if (count) {
 673			err = set_flexbg_block_bitmap(sb, handle,
 674						      flex_gd,
 675						      EXT4_B2C(sbi, start),
 676						      EXT4_B2C(sbi,
 677							       start + count
 678							       - 1));
 679			if (err)
 680				goto out;
 681		}
 682	}
 683
 684out:
 685	brelse(bh);
 686	err2 = ext4_journal_stop(handle);
 687	if (err2 && !err)
 688		err = err2;
 689
 690	return err;
 691}
 692
 693/*
 694 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 695 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 696 * calling this for the first time.  In a sparse filesystem it will be the
 697 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 698 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 699 */
 700static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 701				  unsigned *five, unsigned *seven)
 702{
 703	unsigned *min = three;
 704	int mult = 3;
 705	unsigned ret;
 706
 707	if (!ext4_has_feature_sparse_super(sb)) {
 
 708		ret = *min;
 709		*min += 1;
 710		return ret;
 711	}
 712
 713	if (*five < *min) {
 714		min = five;
 715		mult = 5;
 716	}
 717	if (*seven < *min) {
 718		min = seven;
 719		mult = 7;
 720	}
 721
 722	ret = *min;
 723	*min *= mult;
 724
 725	return ret;
 726}
 727
 728/*
 729 * Check that all of the backup GDT blocks are held in the primary GDT block.
 730 * It is assumed that they are stored in group order.  Returns the number of
 731 * groups in current filesystem that have BACKUPS, or -ve error code.
 732 */
 733static int verify_reserved_gdb(struct super_block *sb,
 734			       ext4_group_t end,
 735			       struct buffer_head *primary)
 736{
 737	const ext4_fsblk_t blk = primary->b_blocknr;
 738	unsigned three = 1;
 739	unsigned five = 5;
 740	unsigned seven = 7;
 741	unsigned grp;
 742	__le32 *p = (__le32 *)primary->b_data;
 743	int gdbackups = 0;
 744
 745	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 746		if (le32_to_cpu(*p++) !=
 747		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 748			ext4_warning(sb, "reserved GDT %llu"
 749				     " missing grp %d (%llu)",
 750				     blk, grp,
 751				     grp *
 752				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 753				     blk);
 754			return -EINVAL;
 755		}
 756		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 757			return -EFBIG;
 758	}
 759
 760	return gdbackups;
 761}
 762
 763/*
 764 * Called when we need to bring a reserved group descriptor table block into
 765 * use from the resize inode.  The primary copy of the new GDT block currently
 766 * is an indirect block (under the double indirect block in the resize inode).
 767 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 768 * block, in group order.  Even though we know all the block numbers we need,
 769 * we check to ensure that the resize inode has actually reserved these blocks.
 770 *
 771 * Don't need to update the block bitmaps because the blocks are still in use.
 772 *
 773 * We get all of the error cases out of the way, so that we are sure to not
 774 * fail once we start modifying the data on disk, because JBD has no rollback.
 775 */
 776static int add_new_gdb(handle_t *handle, struct inode *inode,
 777		       ext4_group_t group)
 778{
 779	struct super_block *sb = inode->i_sb;
 780	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 781	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 782	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 783	struct buffer_head **o_group_desc, **n_group_desc;
 784	struct buffer_head *dind;
 785	struct buffer_head *gdb_bh;
 786	int gdbackups;
 787	struct ext4_iloc iloc;
 788	__le32 *data;
 789	int err;
 790
 791	if (test_opt(sb, DEBUG))
 792		printk(KERN_DEBUG
 793		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 794		       gdb_num);
 795
 
 
 
 
 
 
 
 
 
 
 
 
 796	gdb_bh = sb_bread(sb, gdblock);
 797	if (!gdb_bh)
 798		return -EIO;
 799
 800	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 801	if (gdbackups < 0) {
 802		err = gdbackups;
 803		goto exit_bh;
 804	}
 805
 806	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 807	dind = sb_bread(sb, le32_to_cpu(*data));
 808	if (!dind) {
 809		err = -EIO;
 810		goto exit_bh;
 811	}
 812
 813	data = (__le32 *)dind->b_data;
 814	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 815		ext4_warning(sb, "new group %u GDT block %llu not reserved",
 816			     group, gdblock);
 817		err = -EINVAL;
 818		goto exit_dind;
 819	}
 820
 821	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 822	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 823	if (unlikely(err))
 824		goto exit_dind;
 825
 826	BUFFER_TRACE(gdb_bh, "get_write_access");
 827	err = ext4_journal_get_write_access(handle, gdb_bh);
 828	if (unlikely(err))
 829		goto exit_dind;
 830
 831	BUFFER_TRACE(dind, "get_write_access");
 832	err = ext4_journal_get_write_access(handle, dind);
 833	if (unlikely(err))
 834		ext4_std_error(sb, err);
 835
 836	/* ext4_reserve_inode_write() gets a reference on the iloc */
 837	err = ext4_reserve_inode_write(handle, inode, &iloc);
 838	if (unlikely(err))
 839		goto exit_dind;
 840
 841	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 842				     sizeof(struct buffer_head *),
 843				     GFP_NOFS);
 844	if (!n_group_desc) {
 845		err = -ENOMEM;
 846		ext4_warning(sb, "not enough memory for %lu groups",
 847			     gdb_num + 1);
 848		goto exit_inode;
 849	}
 850
 851	/*
 852	 * Finally, we have all of the possible failures behind us...
 853	 *
 854	 * Remove new GDT block from inode double-indirect block and clear out
 855	 * the new GDT block for use (which also "frees" the backup GDT blocks
 856	 * from the reserved inode).  We don't need to change the bitmaps for
 857	 * these blocks, because they are marked as in-use from being in the
 858	 * reserved inode, and will become GDT blocks (primary and backup).
 859	 */
 860	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 861	err = ext4_handle_dirty_metadata(handle, NULL, dind);
 862	if (unlikely(err)) {
 863		ext4_std_error(sb, err);
 864		goto exit_inode;
 865	}
 866	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 867			   (9 - EXT4_SB(sb)->s_cluster_bits);
 868	ext4_mark_iloc_dirty(handle, inode, &iloc);
 869	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 870	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 871	if (unlikely(err)) {
 872		ext4_std_error(sb, err);
 873		goto exit_inode;
 874	}
 875	brelse(dind);
 876
 877	o_group_desc = EXT4_SB(sb)->s_group_desc;
 878	memcpy(n_group_desc, o_group_desc,
 879	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 880	n_group_desc[gdb_num] = gdb_bh;
 881	EXT4_SB(sb)->s_group_desc = n_group_desc;
 882	EXT4_SB(sb)->s_gdb_count++;
 883	kvfree(o_group_desc);
 884
 885	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 886	err = ext4_handle_dirty_super(handle, sb);
 887	if (err)
 888		ext4_std_error(sb, err);
 889
 890	return err;
 891
 892exit_inode:
 893	kvfree(n_group_desc);
 894	brelse(iloc.bh);
 895exit_dind:
 896	brelse(dind);
 897exit_bh:
 898	brelse(gdb_bh);
 899
 900	ext4_debug("leaving with error %d\n", err);
 901	return err;
 902}
 903
 904/*
 905 * add_new_gdb_meta_bg is the sister of add_new_gdb.
 906 */
 907static int add_new_gdb_meta_bg(struct super_block *sb,
 908			       handle_t *handle, ext4_group_t group) {
 909	ext4_fsblk_t gdblock;
 910	struct buffer_head *gdb_bh;
 911	struct buffer_head **o_group_desc, **n_group_desc;
 912	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 913	int err;
 914
 915	gdblock = ext4_meta_bg_first_block_no(sb, group) +
 916		   ext4_bg_has_super(sb, group);
 917	gdb_bh = sb_bread(sb, gdblock);
 918	if (!gdb_bh)
 919		return -EIO;
 920	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 921				     sizeof(struct buffer_head *),
 922				     GFP_NOFS);
 923	if (!n_group_desc) {
 924		err = -ENOMEM;
 925		ext4_warning(sb, "not enough memory for %lu groups",
 926			     gdb_num + 1);
 927		return err;
 928	}
 929
 930	o_group_desc = EXT4_SB(sb)->s_group_desc;
 931	memcpy(n_group_desc, o_group_desc,
 932	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 933	n_group_desc[gdb_num] = gdb_bh;
 934	EXT4_SB(sb)->s_group_desc = n_group_desc;
 935	EXT4_SB(sb)->s_gdb_count++;
 936	kvfree(o_group_desc);
 937	BUFFER_TRACE(gdb_bh, "get_write_access");
 938	err = ext4_journal_get_write_access(handle, gdb_bh);
 939	if (unlikely(err))
 940		brelse(gdb_bh);
 941	return err;
 942}
 943
 944/*
 945 * Called when we are adding a new group which has a backup copy of each of
 946 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 947 * We need to add these reserved backup GDT blocks to the resize inode, so
 948 * that they are kept for future resizing and not allocated to files.
 949 *
 950 * Each reserved backup GDT block will go into a different indirect block.
 951 * The indirect blocks are actually the primary reserved GDT blocks,
 952 * so we know in advance what their block numbers are.  We only get the
 953 * double-indirect block to verify it is pointing to the primary reserved
 954 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 955 * backup GDT blocks are stored in their reserved primary GDT block.
 956 */
 957static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 958			      ext4_group_t group)
 959{
 960	struct super_block *sb = inode->i_sb;
 961	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 962	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 963	struct buffer_head **primary;
 964	struct buffer_head *dind;
 965	struct ext4_iloc iloc;
 966	ext4_fsblk_t blk;
 967	__le32 *data, *end;
 968	int gdbackups = 0;
 969	int res, i;
 970	int err;
 971
 972	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 973	if (!primary)
 974		return -ENOMEM;
 975
 976	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 977	dind = sb_bread(sb, le32_to_cpu(*data));
 978	if (!dind) {
 979		err = -EIO;
 980		goto exit_free;
 981	}
 982
 983	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 984	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 985					 EXT4_ADDR_PER_BLOCK(sb));
 986	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 987
 988	/* Get each reserved primary GDT block and verify it holds backups */
 989	for (res = 0; res < reserved_gdb; res++, blk++) {
 990		if (le32_to_cpu(*data) != blk) {
 991			ext4_warning(sb, "reserved block %llu"
 992				     " not at offset %ld",
 993				     blk,
 994				     (long)(data - (__le32 *)dind->b_data));
 995			err = -EINVAL;
 996			goto exit_bh;
 997		}
 998		primary[res] = sb_bread(sb, blk);
 999		if (!primary[res]) {
1000			err = -EIO;
1001			goto exit_bh;
1002		}
1003		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1004		if (gdbackups < 0) {
1005			brelse(primary[res]);
1006			err = gdbackups;
1007			goto exit_bh;
1008		}
1009		if (++data >= end)
1010			data = (__le32 *)dind->b_data;
1011	}
1012
1013	for (i = 0; i < reserved_gdb; i++) {
1014		BUFFER_TRACE(primary[i], "get_write_access");
1015		if ((err = ext4_journal_get_write_access(handle, primary[i])))
1016			goto exit_bh;
1017	}
1018
1019	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1020		goto exit_bh;
1021
1022	/*
1023	 * Finally we can add each of the reserved backup GDT blocks from
1024	 * the new group to its reserved primary GDT block.
1025	 */
1026	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1027	for (i = 0; i < reserved_gdb; i++) {
1028		int err2;
1029		data = (__le32 *)primary[i]->b_data;
1030		/* printk("reserving backup %lu[%u] = %lu\n",
1031		       primary[i]->b_blocknr, gdbackups,
1032		       blk + primary[i]->b_blocknr); */
1033		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1034		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1035		if (!err)
1036			err = err2;
1037	}
1038
1039	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1040	ext4_mark_iloc_dirty(handle, inode, &iloc);
1041
1042exit_bh:
1043	while (--res >= 0)
1044		brelse(primary[res]);
1045	brelse(dind);
1046
1047exit_free:
1048	kfree(primary);
1049
1050	return err;
1051}
1052
1053/*
1054 * Update the backup copies of the ext4 metadata.  These don't need to be part
1055 * of the main resize transaction, because e2fsck will re-write them if there
1056 * is a problem (basically only OOM will cause a problem).  However, we
1057 * _should_ update the backups if possible, in case the primary gets trashed
1058 * for some reason and we need to run e2fsck from a backup superblock.  The
1059 * important part is that the new block and inode counts are in the backup
1060 * superblocks, and the location of the new group metadata in the GDT backups.
1061 *
1062 * We do not need take the s_resize_lock for this, because these
1063 * blocks are not otherwise touched by the filesystem code when it is
1064 * mounted.  We don't need to worry about last changing from
1065 * sbi->s_groups_count, because the worst that can happen is that we
1066 * do not copy the full number of backups at this time.  The resize
1067 * which changed s_groups_count will backup again.
1068 */
1069static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1070			   int size, int meta_bg)
1071{
1072	struct ext4_sb_info *sbi = EXT4_SB(sb);
1073	ext4_group_t last;
1074	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1075	unsigned three = 1;
1076	unsigned five = 5;
1077	unsigned seven = 7;
1078	ext4_group_t group = 0;
1079	int rest = sb->s_blocksize - size;
1080	handle_t *handle;
1081	int err = 0, err2;
1082
1083	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1084	if (IS_ERR(handle)) {
1085		group = 1;
1086		err = PTR_ERR(handle);
1087		goto exit_err;
1088	}
1089
1090	if (meta_bg == 0) {
1091		group = ext4_list_backups(sb, &three, &five, &seven);
1092		last = sbi->s_groups_count;
1093	} else {
1094		group = ext4_get_group_number(sb, blk_off) + 1;
1095		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1096	}
1097
1098	while (group < sbi->s_groups_count) {
1099		struct buffer_head *bh;
1100		ext4_fsblk_t backup_block;
1101
1102		/* Out of journal space, and can't get more - abort - so sad */
1103		if (ext4_handle_valid(handle) &&
1104		    handle->h_buffer_credits == 0 &&
1105		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1106		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1107			break;
1108
1109		if (meta_bg == 0)
1110			backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1111		else
1112			backup_block = (ext4_group_first_block_no(sb, group) +
1113					ext4_bg_has_super(sb, group));
1114
1115		bh = sb_getblk(sb, backup_block);
1116		if (unlikely(!bh)) {
1117			err = -ENOMEM;
1118			break;
1119		}
1120		ext4_debug("update metadata backup %llu(+%llu)\n",
1121			   backup_block, backup_block -
1122			   ext4_group_first_block_no(sb, group));
1123		BUFFER_TRACE(bh, "get_write_access");
1124		if ((err = ext4_journal_get_write_access(handle, bh)))
1125			break;
1126		lock_buffer(bh);
1127		memcpy(bh->b_data, data, size);
1128		if (rest)
1129			memset(bh->b_data + size, 0, rest);
1130		set_buffer_uptodate(bh);
1131		unlock_buffer(bh);
1132		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1133		if (unlikely(err))
1134			ext4_std_error(sb, err);
1135		brelse(bh);
1136
1137		if (meta_bg == 0)
1138			group = ext4_list_backups(sb, &three, &five, &seven);
1139		else if (group == last)
1140			break;
1141		else
1142			group = last;
1143	}
1144	if ((err2 = ext4_journal_stop(handle)) && !err)
1145		err = err2;
1146
1147	/*
1148	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1149	 * late to revert the resize, we shouldn't fail just because of
1150	 * the backup copies (they are only needed in case of corruption).
1151	 *
1152	 * However, if we got here we have a journal problem too, so we
1153	 * can't really start a transaction to mark the superblock.
1154	 * Chicken out and just set the flag on the hope it will be written
1155	 * to disk, and if not - we will simply wait until next fsck.
1156	 */
1157exit_err:
1158	if (err) {
1159		ext4_warning(sb, "can't update backup for group %u (err %d), "
1160			     "forcing fsck on next reboot", group, err);
1161		sbi->s_mount_state &= ~EXT4_VALID_FS;
1162		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1163		mark_buffer_dirty(sbi->s_sbh);
1164	}
1165}
1166
1167/*
1168 * ext4_add_new_descs() adds @count group descriptor of groups
1169 * starting at @group
1170 *
1171 * @handle: journal handle
1172 * @sb: super block
1173 * @group: the group no. of the first group desc to be added
1174 * @resize_inode: the resize inode
1175 * @count: number of group descriptors to be added
1176 */
1177static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1178			      ext4_group_t group, struct inode *resize_inode,
1179			      ext4_group_t count)
1180{
1181	struct ext4_sb_info *sbi = EXT4_SB(sb);
1182	struct ext4_super_block *es = sbi->s_es;
1183	struct buffer_head *gdb_bh;
1184	int i, gdb_off, gdb_num, err = 0;
1185	int meta_bg;
1186
1187	meta_bg = ext4_has_feature_meta_bg(sb);
1188	for (i = 0; i < count; i++, group++) {
1189		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1190			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1191
1192		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1193		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1194
1195		/*
1196		 * We will only either add reserved group blocks to a backup group
1197		 * or remove reserved blocks for the first group in a new group block.
1198		 * Doing both would be mean more complex code, and sane people don't
1199		 * use non-sparse filesystems anymore.  This is already checked above.
1200		 */
1201		if (gdb_off) {
1202			gdb_bh = sbi->s_group_desc[gdb_num];
1203			BUFFER_TRACE(gdb_bh, "get_write_access");
1204			err = ext4_journal_get_write_access(handle, gdb_bh);
1205
1206			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1207				err = reserve_backup_gdb(handle, resize_inode, group);
1208		} else if (meta_bg != 0) {
1209			err = add_new_gdb_meta_bg(sb, handle, group);
1210		} else {
1211			err = add_new_gdb(handle, resize_inode, group);
1212		}
1213		if (err)
1214			break;
1215	}
1216	return err;
1217}
1218
1219static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1220{
1221	struct buffer_head *bh = sb_getblk(sb, block);
1222	if (unlikely(!bh))
1223		return NULL;
1224	if (!bh_uptodate_or_lock(bh)) {
1225		if (bh_submit_read(bh) < 0) {
1226			brelse(bh);
1227			return NULL;
1228		}
1229	}
1230
1231	return bh;
1232}
1233
1234static int ext4_set_bitmap_checksums(struct super_block *sb,
1235				     ext4_group_t group,
1236				     struct ext4_group_desc *gdp,
1237				     struct ext4_new_group_data *group_data)
1238{
1239	struct buffer_head *bh;
1240
1241	if (!ext4_has_metadata_csum(sb))
 
1242		return 0;
1243
1244	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1245	if (!bh)
1246		return -EIO;
1247	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1248				   EXT4_INODES_PER_GROUP(sb) / 8);
1249	brelse(bh);
1250
1251	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1252	if (!bh)
1253		return -EIO;
1254	ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1255	brelse(bh);
1256
1257	return 0;
1258}
1259
1260/*
1261 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1262 */
1263static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1264				struct ext4_new_flex_group_data *flex_gd)
1265{
1266	struct ext4_new_group_data	*group_data = flex_gd->groups;
1267	struct ext4_group_desc		*gdp;
1268	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1269	struct buffer_head		*gdb_bh;
1270	ext4_group_t			group;
1271	__u16				*bg_flags = flex_gd->bg_flags;
1272	int				i, gdb_off, gdb_num, err = 0;
1273
1274
1275	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1276		group = group_data->group;
1277
1278		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1279		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1280
1281		/*
1282		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1283		 */
1284		gdb_bh = sbi->s_group_desc[gdb_num];
1285		/* Update group descriptor block for new group */
1286		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1287						 gdb_off * EXT4_DESC_SIZE(sb));
1288
1289		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1290		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1291		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1292		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1293		if (err) {
1294			ext4_std_error(sb, err);
1295			break;
1296		}
1297
1298		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1299		ext4_free_group_clusters_set(sb, gdp,
1300					     group_data->free_clusters_count);
1301		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1302		if (ext4_has_group_desc_csum(sb))
1303			ext4_itable_unused_set(sb, gdp,
1304					       EXT4_INODES_PER_GROUP(sb));
1305		gdp->bg_flags = cpu_to_le16(*bg_flags);
1306		ext4_group_desc_csum_set(sb, group, gdp);
1307
1308		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1309		if (unlikely(err)) {
1310			ext4_std_error(sb, err);
1311			break;
1312		}
1313
1314		/*
1315		 * We can allocate memory for mb_alloc based on the new group
1316		 * descriptor
1317		 */
1318		err = ext4_mb_add_groupinfo(sb, group, gdp);
1319		if (err)
1320			break;
1321	}
1322	return err;
1323}
1324
1325/*
1326 * ext4_update_super() updates the super block so that the newly added
1327 * groups can be seen by the filesystem.
1328 *
1329 * @sb: super block
1330 * @flex_gd: new added groups
1331 */
1332static void ext4_update_super(struct super_block *sb,
1333			     struct ext4_new_flex_group_data *flex_gd)
1334{
1335	ext4_fsblk_t blocks_count = 0;
1336	ext4_fsblk_t free_blocks = 0;
1337	ext4_fsblk_t reserved_blocks = 0;
1338	struct ext4_new_group_data *group_data = flex_gd->groups;
1339	struct ext4_sb_info *sbi = EXT4_SB(sb);
1340	struct ext4_super_block *es = sbi->s_es;
1341	int i;
1342
1343	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1344	/*
1345	 * Make the new blocks and inodes valid next.  We do this before
1346	 * increasing the group count so that once the group is enabled,
1347	 * all of its blocks and inodes are already valid.
1348	 *
1349	 * We always allocate group-by-group, then block-by-block or
1350	 * inode-by-inode within a group, so enabling these
1351	 * blocks/inodes before the group is live won't actually let us
1352	 * allocate the new space yet.
1353	 */
1354	for (i = 0; i < flex_gd->count; i++) {
1355		blocks_count += group_data[i].blocks_count;
1356		free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1357	}
1358
1359	reserved_blocks = ext4_r_blocks_count(es) * 100;
1360	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1361	reserved_blocks *= blocks_count;
1362	do_div(reserved_blocks, 100);
1363
1364	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1365	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1366	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1367		     flex_gd->count);
1368	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1369		     flex_gd->count);
1370
1371	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1372	/*
1373	 * We need to protect s_groups_count against other CPUs seeing
1374	 * inconsistent state in the superblock.
1375	 *
1376	 * The precise rules we use are:
1377	 *
1378	 * * Writers must perform a smp_wmb() after updating all
1379	 *   dependent data and before modifying the groups count
1380	 *
1381	 * * Readers must perform an smp_rmb() after reading the groups
1382	 *   count and before reading any dependent data.
1383	 *
1384	 * NB. These rules can be relaxed when checking the group count
1385	 * while freeing data, as we can only allocate from a block
1386	 * group after serialising against the group count, and we can
1387	 * only then free after serialising in turn against that
1388	 * allocation.
1389	 */
1390	smp_wmb();
1391
1392	/* Update the global fs size fields */
1393	sbi->s_groups_count += flex_gd->count;
1394	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1395			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1396
1397	/* Update the reserved block counts only once the new group is
1398	 * active. */
1399	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1400				reserved_blocks);
1401
1402	/* Update the free space counts */
1403	percpu_counter_add(&sbi->s_freeclusters_counter,
1404			   EXT4_NUM_B2C(sbi, free_blocks));
1405	percpu_counter_add(&sbi->s_freeinodes_counter,
1406			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1407
1408	ext4_debug("free blocks count %llu",
1409		   percpu_counter_read(&sbi->s_freeclusters_counter));
1410	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
 
 
1411		ext4_group_t flex_group;
1412		flex_group = ext4_flex_group(sbi, group_data[0].group);
1413		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1414			     &sbi->s_flex_groups[flex_group].free_clusters);
1415		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1416			   &sbi->s_flex_groups[flex_group].free_inodes);
1417	}
1418
1419	/*
1420	 * Update the fs overhead information
1421	 */
1422	ext4_calculate_overhead(sb);
1423
1424	if (test_opt(sb, DEBUG))
1425		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1426		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1427		       blocks_count, free_blocks, reserved_blocks);
1428}
1429
1430/* Add a flex group to an fs. Ensure we handle all possible error conditions
1431 * _before_ we start modifying the filesystem, because we cannot abort the
1432 * transaction and not have it write the data to disk.
1433 */
1434static int ext4_flex_group_add(struct super_block *sb,
1435			       struct inode *resize_inode,
1436			       struct ext4_new_flex_group_data *flex_gd)
1437{
1438	struct ext4_sb_info *sbi = EXT4_SB(sb);
1439	struct ext4_super_block *es = sbi->s_es;
1440	ext4_fsblk_t o_blocks_count;
1441	ext4_grpblk_t last;
1442	ext4_group_t group;
1443	handle_t *handle;
1444	unsigned reserved_gdb;
1445	int err = 0, err2 = 0, credit;
1446
1447	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1448
1449	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1450	o_blocks_count = ext4_blocks_count(es);
1451	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1452	BUG_ON(last);
1453
1454	err = setup_new_flex_group_blocks(sb, flex_gd);
1455	if (err)
1456		goto exit;
1457	/*
1458	 * We will always be modifying at least the superblock and  GDT
1459	 * blocks.  If we are adding a group past the last current GDT block,
1460	 * we will also modify the inode and the dindirect block.  If we
1461	 * are adding a group with superblock/GDT backups  we will also
1462	 * modify each of the reserved GDT dindirect blocks.
1463	 */
1464	credit = 3;	/* sb, resize inode, resize inode dindirect */
1465	/* GDT blocks */
1466	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1467	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
1468	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1469	if (IS_ERR(handle)) {
1470		err = PTR_ERR(handle);
1471		goto exit;
1472	}
1473
1474	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1475	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1476	if (err)
1477		goto exit_journal;
1478
1479	group = flex_gd->groups[0].group;
1480	BUG_ON(group != sbi->s_groups_count);
1481	err = ext4_add_new_descs(handle, sb, group,
1482				resize_inode, flex_gd->count);
1483	if (err)
1484		goto exit_journal;
1485
1486	err = ext4_setup_new_descs(handle, sb, flex_gd);
1487	if (err)
1488		goto exit_journal;
1489
1490	ext4_update_super(sb, flex_gd);
1491
1492	err = ext4_handle_dirty_super(handle, sb);
1493
1494exit_journal:
1495	err2 = ext4_journal_stop(handle);
1496	if (!err)
1497		err = err2;
1498
1499	if (!err) {
1500		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1501		int gdb_num_end = ((group + flex_gd->count - 1) /
1502				   EXT4_DESC_PER_BLOCK(sb));
1503		int meta_bg = ext4_has_feature_meta_bg(sb);
 
1504		sector_t old_gdb = 0;
1505
1506		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1507			       sizeof(struct ext4_super_block), 0);
1508		for (; gdb_num <= gdb_num_end; gdb_num++) {
1509			struct buffer_head *gdb_bh;
1510
1511			gdb_bh = sbi->s_group_desc[gdb_num];
1512			if (old_gdb == gdb_bh->b_blocknr)
1513				continue;
1514			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1515				       gdb_bh->b_size, meta_bg);
1516			old_gdb = gdb_bh->b_blocknr;
1517		}
1518	}
1519exit:
1520	return err;
1521}
1522
1523static int ext4_setup_next_flex_gd(struct super_block *sb,
1524				    struct ext4_new_flex_group_data *flex_gd,
1525				    ext4_fsblk_t n_blocks_count,
1526				    unsigned long flexbg_size)
1527{
1528	struct ext4_sb_info *sbi = EXT4_SB(sb);
1529	struct ext4_super_block *es = sbi->s_es;
1530	struct ext4_new_group_data *group_data = flex_gd->groups;
1531	ext4_fsblk_t o_blocks_count;
1532	ext4_group_t n_group;
1533	ext4_group_t group;
1534	ext4_group_t last_group;
1535	ext4_grpblk_t last;
1536	ext4_grpblk_t clusters_per_group;
1537	unsigned long i;
1538
1539	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1540
1541	o_blocks_count = ext4_blocks_count(es);
1542
1543	if (o_blocks_count == n_blocks_count)
1544		return 0;
1545
1546	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1547	BUG_ON(last);
1548	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1549
1550	last_group = group | (flexbg_size - 1);
1551	if (last_group > n_group)
1552		last_group = n_group;
1553
1554	flex_gd->count = last_group - group + 1;
1555
1556	for (i = 0; i < flex_gd->count; i++) {
1557		int overhead;
1558
1559		group_data[i].group = group + i;
1560		group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1561		overhead = ext4_group_overhead_blocks(sb, group + i);
1562		group_data[i].mdata_blocks = overhead;
1563		group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1564		if (ext4_has_group_desc_csum(sb)) {
1565			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1566					       EXT4_BG_INODE_UNINIT;
1567			if (!test_opt(sb, INIT_INODE_TABLE))
1568				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1569		} else
1570			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1571	}
1572
1573	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1574		/* We need to initialize block bitmap of last group. */
1575		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1576
1577	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1578		group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1579		group_data[i - 1].free_clusters_count -= clusters_per_group -
1580						       last - 1;
1581	}
1582
1583	return 1;
1584}
1585
1586/* Add group descriptor data to an existing or new group descriptor block.
1587 * Ensure we handle all possible error conditions _before_ we start modifying
1588 * the filesystem, because we cannot abort the transaction and not have it
1589 * write the data to disk.
1590 *
1591 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1592 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1593 *
1594 * We only need to hold the superblock lock while we are actually adding
1595 * in the new group's counts to the superblock.  Prior to that we have
1596 * not really "added" the group at all.  We re-check that we are still
1597 * adding in the last group in case things have changed since verifying.
1598 */
1599int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1600{
1601	struct ext4_new_flex_group_data flex_gd;
1602	struct ext4_sb_info *sbi = EXT4_SB(sb);
1603	struct ext4_super_block *es = sbi->s_es;
1604	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1605		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1606	struct inode *inode = NULL;
1607	int gdb_off;
1608	int err;
1609	__u16 bg_flags = 0;
1610
1611	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1612
1613	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
 
1614		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1615		return -EPERM;
1616	}
1617
1618	if (ext4_blocks_count(es) + input->blocks_count <
1619	    ext4_blocks_count(es)) {
1620		ext4_warning(sb, "blocks_count overflow");
1621		return -EINVAL;
1622	}
1623
1624	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1625	    le32_to_cpu(es->s_inodes_count)) {
1626		ext4_warning(sb, "inodes_count overflow");
1627		return -EINVAL;
1628	}
1629
1630	if (reserved_gdb || gdb_off == 0) {
1631		if (ext4_has_feature_resize_inode(sb) ||
1632		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
 
1633			ext4_warning(sb,
1634				     "No reserved GDT blocks, can't resize");
1635			return -EPERM;
1636		}
1637		inode = ext4_iget(sb, EXT4_RESIZE_INO);
1638		if (IS_ERR(inode)) {
1639			ext4_warning(sb, "Error opening resize inode");
1640			return PTR_ERR(inode);
1641		}
1642	}
1643
1644
1645	err = verify_group_input(sb, input);
1646	if (err)
1647		goto out;
1648
1649	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1650	if (err)
1651		goto out;
1652
1653	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1654	if (err)
1655		goto out;
1656
1657	flex_gd.count = 1;
1658	flex_gd.groups = input;
1659	flex_gd.bg_flags = &bg_flags;
1660	err = ext4_flex_group_add(sb, inode, &flex_gd);
1661out:
1662	iput(inode);
1663	return err;
1664} /* ext4_group_add */
1665
1666/*
1667 * extend a group without checking assuming that checking has been done.
1668 */
1669static int ext4_group_extend_no_check(struct super_block *sb,
1670				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1671{
1672	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1673	handle_t *handle;
1674	int err = 0, err2;
1675
1676	/* We will update the superblock, one block bitmap, and
1677	 * one group descriptor via ext4_group_add_blocks().
1678	 */
1679	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1680	if (IS_ERR(handle)) {
1681		err = PTR_ERR(handle);
1682		ext4_warning(sb, "error %d on journal start", err);
1683		return err;
1684	}
1685
1686	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1687	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1688	if (err) {
1689		ext4_warning(sb, "error %d on journal write access", err);
1690		goto errout;
1691	}
1692
1693	ext4_blocks_count_set(es, o_blocks_count + add);
1694	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1695	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1696		   o_blocks_count + add);
1697	/* We add the blocks to the bitmap and set the group need init bit */
1698	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1699	if (err)
1700		goto errout;
1701	ext4_handle_dirty_super(handle, sb);
1702	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1703		   o_blocks_count + add);
1704errout:
1705	err2 = ext4_journal_stop(handle);
1706	if (err2 && !err)
1707		err = err2;
1708
1709	if (!err) {
1710		if (test_opt(sb, DEBUG))
1711			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1712			       "blocks\n", ext4_blocks_count(es));
1713		update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1714			       (char *)es, sizeof(struct ext4_super_block), 0);
1715	}
1716	return err;
1717}
1718
1719/*
1720 * Extend the filesystem to the new number of blocks specified.  This entry
1721 * point is only used to extend the current filesystem to the end of the last
1722 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1723 * for emergencies (because it has no dependencies on reserved blocks).
1724 *
1725 * If we _really_ wanted, we could use default values to call ext4_group_add()
1726 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1727 * GDT blocks are reserved to grow to the desired size.
1728 */
1729int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1730		      ext4_fsblk_t n_blocks_count)
1731{
1732	ext4_fsblk_t o_blocks_count;
1733	ext4_grpblk_t last;
1734	ext4_grpblk_t add;
1735	struct buffer_head *bh;
1736	int err;
1737	ext4_group_t group;
1738
1739	o_blocks_count = ext4_blocks_count(es);
1740
1741	if (test_opt(sb, DEBUG))
1742		ext4_msg(sb, KERN_DEBUG,
1743			 "extending last group from %llu to %llu blocks",
1744			 o_blocks_count, n_blocks_count);
1745
1746	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1747		return 0;
1748
1749	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1750		ext4_msg(sb, KERN_ERR,
1751			 "filesystem too large to resize to %llu blocks safely",
1752			 n_blocks_count);
1753		if (sizeof(sector_t) < 8)
1754			ext4_warning(sb, "CONFIG_LBDAF not enabled");
1755		return -EINVAL;
1756	}
1757
1758	if (n_blocks_count < o_blocks_count) {
1759		ext4_warning(sb, "can't shrink FS - resize aborted");
1760		return -EINVAL;
1761	}
1762
1763	/* Handle the remaining blocks in the last group only. */
1764	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1765
1766	if (last == 0) {
1767		ext4_warning(sb, "need to use ext2online to resize further");
1768		return -EPERM;
1769	}
1770
1771	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1772
1773	if (o_blocks_count + add < o_blocks_count) {
1774		ext4_warning(sb, "blocks_count overflow");
1775		return -EINVAL;
1776	}
1777
1778	if (o_blocks_count + add > n_blocks_count)
1779		add = n_blocks_count - o_blocks_count;
1780
1781	if (o_blocks_count + add < n_blocks_count)
1782		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1783			     o_blocks_count + add, add);
1784
1785	/* See if the device is actually as big as what was requested */
1786	bh = sb_bread(sb, o_blocks_count + add - 1);
1787	if (!bh) {
1788		ext4_warning(sb, "can't read last block, resize aborted");
1789		return -ENOSPC;
1790	}
1791	brelse(bh);
1792
1793	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1794	return err;
1795} /* ext4_group_extend */
1796
1797
1798static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1799{
1800	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1801}
1802
1803/*
1804 * Release the resize inode and drop the resize_inode feature if there
1805 * are no more reserved gdt blocks, and then convert the file system
1806 * to enable meta_bg
1807 */
1808static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1809{
1810	handle_t *handle;
1811	struct ext4_sb_info *sbi = EXT4_SB(sb);
1812	struct ext4_super_block *es = sbi->s_es;
1813	struct ext4_inode_info *ei = EXT4_I(inode);
1814	ext4_fsblk_t nr;
1815	int i, ret, err = 0;
1816	int credits = 1;
1817
1818	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1819	if (inode) {
1820		if (es->s_reserved_gdt_blocks) {
1821			ext4_error(sb, "Unexpected non-zero "
1822				   "s_reserved_gdt_blocks");
1823			return -EPERM;
1824		}
1825
1826		/* Do a quick sanity check of the resize inode */
1827		if (inode->i_blocks != 1 << (inode->i_blkbits -
1828					     (9 - sbi->s_cluster_bits)))
1829			goto invalid_resize_inode;
1830		for (i = 0; i < EXT4_N_BLOCKS; i++) {
1831			if (i == EXT4_DIND_BLOCK) {
1832				if (ei->i_data[i])
1833					continue;
1834				else
1835					goto invalid_resize_inode;
1836			}
1837			if (ei->i_data[i])
1838				goto invalid_resize_inode;
1839		}
1840		credits += 3;	/* block bitmap, bg descriptor, resize inode */
1841	}
1842
1843	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1844	if (IS_ERR(handle))
1845		return PTR_ERR(handle);
1846
1847	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1848	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1849	if (err)
1850		goto errout;
1851
1852	ext4_clear_feature_resize_inode(sb);
1853	ext4_set_feature_meta_bg(sb);
1854	sbi->s_es->s_first_meta_bg =
1855		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1856
1857	err = ext4_handle_dirty_super(handle, sb);
1858	if (err) {
1859		ext4_std_error(sb, err);
1860		goto errout;
1861	}
1862
1863	if (inode) {
1864		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1865		ext4_free_blocks(handle, inode, NULL, nr, 1,
1866				 EXT4_FREE_BLOCKS_METADATA |
1867				 EXT4_FREE_BLOCKS_FORGET);
1868		ei->i_data[EXT4_DIND_BLOCK] = 0;
1869		inode->i_blocks = 0;
1870
1871		err = ext4_mark_inode_dirty(handle, inode);
1872		if (err)
1873			ext4_std_error(sb, err);
1874	}
1875
1876errout:
1877	ret = ext4_journal_stop(handle);
1878	if (!err)
1879		err = ret;
1880	return ret;
1881
1882invalid_resize_inode:
1883	ext4_error(sb, "corrupted/inconsistent resize inode");
1884	return -EINVAL;
1885}
1886
1887/*
1888 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1889 *
1890 * @sb: super block of the fs to be resized
1891 * @n_blocks_count: the number of blocks resides in the resized fs
1892 */
1893int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1894{
1895	struct ext4_new_flex_group_data *flex_gd = NULL;
1896	struct ext4_sb_info *sbi = EXT4_SB(sb);
1897	struct ext4_super_block *es = sbi->s_es;
1898	struct buffer_head *bh;
1899	struct inode *resize_inode = NULL;
1900	ext4_grpblk_t add, offset;
1901	unsigned long n_desc_blocks;
1902	unsigned long o_desc_blocks;
1903	ext4_group_t o_group;
1904	ext4_group_t n_group;
1905	ext4_fsblk_t o_blocks_count;
1906	ext4_fsblk_t n_blocks_count_retry = 0;
1907	unsigned long last_update_time = 0;
1908	int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1909	int meta_bg;
1910
1911	/* See if the device is actually as big as what was requested */
1912	bh = sb_bread(sb, n_blocks_count - 1);
1913	if (!bh) {
1914		ext4_warning(sb, "can't read last block, resize aborted");
1915		return -ENOSPC;
1916	}
1917	brelse(bh);
1918
1919retry:
1920	o_blocks_count = ext4_blocks_count(es);
1921
1922	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1923		 "to %llu blocks", o_blocks_count, n_blocks_count);
1924
1925	if (n_blocks_count < o_blocks_count) {
1926		/* On-line shrinking not supported */
1927		ext4_warning(sb, "can't shrink FS - resize aborted");
1928		return -EINVAL;
1929	}
1930
1931	if (n_blocks_count == o_blocks_count)
1932		/* Nothing need to do */
1933		return 0;
1934
1935	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1936	if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1937		ext4_warning(sb, "resize would cause inodes_count overflow");
1938		return -EINVAL;
1939	}
1940	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1941
1942	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1943	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1944
1945	meta_bg = ext4_has_feature_meta_bg(sb);
1946
1947	if (ext4_has_feature_resize_inode(sb)) {
1948		if (meta_bg) {
1949			ext4_error(sb, "resize_inode and meta_bg enabled "
1950				   "simultaneously");
1951			return -EINVAL;
1952		}
1953		if (n_desc_blocks > o_desc_blocks +
1954		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
1955			n_blocks_count_retry = n_blocks_count;
1956			n_desc_blocks = o_desc_blocks +
1957				le16_to_cpu(es->s_reserved_gdt_blocks);
1958			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1959			n_blocks_count = (ext4_fsblk_t)n_group *
1960				EXT4_BLOCKS_PER_GROUP(sb);
1961			n_group--; /* set to last group number */
1962		}
1963
1964		if (!resize_inode)
1965			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1966		if (IS_ERR(resize_inode)) {
1967			ext4_warning(sb, "Error opening resize inode");
1968			return PTR_ERR(resize_inode);
1969		}
1970	}
1971
1972	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1973		err = ext4_convert_meta_bg(sb, resize_inode);
1974		if (err)
1975			goto out;
1976		if (resize_inode) {
1977			iput(resize_inode);
1978			resize_inode = NULL;
1979		}
1980		if (n_blocks_count_retry) {
1981			n_blocks_count = n_blocks_count_retry;
1982			n_blocks_count_retry = 0;
1983			goto retry;
1984		}
1985	}
1986
1987	/* extend the last group */
1988	if (n_group == o_group)
1989		add = n_blocks_count - o_blocks_count;
1990	else
1991		add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
1992	if (add > 0) {
1993		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1994		if (err)
1995			goto out;
1996	}
1997
1998	if (ext4_blocks_count(es) == n_blocks_count)
1999		goto out;
2000
2001	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2002	if (err)
2003		return err;
2004
2005	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2006	if (err)
2007		goto out;
2008
2009	flex_gd = alloc_flex_gd(flexbg_size);
2010	if (flex_gd == NULL) {
2011		err = -ENOMEM;
2012		goto out;
2013	}
2014
2015	/* Add flex groups. Note that a regular group is a
2016	 * flex group with 1 group.
2017	 */
2018	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2019					      flexbg_size)) {
2020		if (jiffies - last_update_time > HZ * 10) {
2021			if (last_update_time)
2022				ext4_msg(sb, KERN_INFO,
2023					 "resized to %llu blocks",
2024					 ext4_blocks_count(es));
2025			last_update_time = jiffies;
2026		}
2027		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2028			break;
2029		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2030		if (unlikely(err))
2031			break;
2032	}
2033
2034	if (!err && n_blocks_count_retry) {
2035		n_blocks_count = n_blocks_count_retry;
2036		n_blocks_count_retry = 0;
2037		free_flex_gd(flex_gd);
2038		flex_gd = NULL;
2039		goto retry;
2040	}
2041
2042out:
2043	if (flex_gd)
2044		free_flex_gd(flex_gd);
2045	if (resize_inode != NULL)
2046		iput(resize_inode);
2047	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2048	return err;
2049}