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#include <linux/errno.h>
  14#include <linux/slab.h>
  15#include <linux/jiffies.h>
  16
  17#include "ext4_jbd2.h"
  18
  19struct ext4_rcu_ptr {
  20	struct rcu_head rcu;
  21	void *ptr;
  22};
  23
  24static void ext4_rcu_ptr_callback(struct rcu_head *head)
  25{
  26	struct ext4_rcu_ptr *ptr;
  27
  28	ptr = container_of(head, struct ext4_rcu_ptr, rcu);
  29	kvfree(ptr->ptr);
  30	kfree(ptr);
  31}
  32
  33void ext4_kvfree_array_rcu(void *to_free)
  34{
  35	struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
  36
  37	if (ptr) {
  38		ptr->ptr = to_free;
  39		call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
  40		return;
  41	}
  42	synchronize_rcu();
  43	kvfree(to_free);
  44}
  45
  46int ext4_resize_begin(struct super_block *sb)
  47{
  48	struct ext4_sb_info *sbi = EXT4_SB(sb);
  49	int ret = 0;
  50
  51	if (!capable(CAP_SYS_RESOURCE))
  52		return -EPERM;
  53
  54	/*
  55	 * If the reserved GDT blocks is non-zero, the resize_inode feature
  56	 * should always be set.
  57	 */
  58	if (sbi->s_es->s_reserved_gdt_blocks &&
  59	    !ext4_has_feature_resize_inode(sb)) {
  60		ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
  61		return -EFSCORRUPTED;
  62	}
  63
  64	/*
  65	 * If we are not using the primary superblock/GDT copy don't resize,
  66         * because the user tools have no way of handling this.  Probably a
  67         * bad time to do it anyways.
  68         */
  69	if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  70	    le32_to_cpu(sbi->s_es->s_first_data_block)) {
  71		ext4_warning(sb, "won't resize using backup superblock at %llu",
  72			(unsigned long long)sbi->s_sbh->b_blocknr);
  73		return -EPERM;
  74	}
  75
  76	/*
  77	 * We are not allowed to do online-resizing on a filesystem mounted
  78	 * with error, because it can destroy the filesystem easily.
  79	 */
  80	if (sbi->s_mount_state & EXT4_ERROR_FS) {
  81		ext4_warning(sb, "There are errors in the filesystem, "
  82			     "so online resizing is not allowed");
  83		return -EPERM;
  84	}
  85
  86	if (ext4_has_feature_sparse_super2(sb)) {
  87		ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
  88		return -EOPNOTSUPP;
  89	}
  90
  91	if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  92				  &sbi->s_ext4_flags))
  93		ret = -EBUSY;
  94
  95	return ret;
  96}
  97
  98int ext4_resize_end(struct super_block *sb, bool update_backups)
  99{
 100	clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
 101	smp_mb__after_atomic();
 102	if (update_backups)
 103		return ext4_update_overhead(sb, true);
 104	return 0;
 
 
 
 
 
 
 
 
 
 105}
 106
 107static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 108						ext4_group_t group) {
 109	ext4_grpblk_t overhead;
 110	overhead = ext4_bg_num_gdb(sb, group);
 111	if (ext4_bg_has_super(sb, group))
 112		overhead += 1 +
 113			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 114	return overhead;
 115}
 116
 117#define outside(b, first, last)	((b) < (first) || (b) >= (last))
 118#define inside(b, first, last)	((b) >= (first) && (b) < (last))
 119
 120static int verify_group_input(struct super_block *sb,
 121			      struct ext4_new_group_data *input)
 122{
 123	struct ext4_sb_info *sbi = EXT4_SB(sb);
 124	struct ext4_super_block *es = sbi->s_es;
 125	ext4_fsblk_t start = ext4_blocks_count(es);
 126	ext4_fsblk_t end = start + input->blocks_count;
 127	ext4_group_t group = input->group;
 128	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 129	unsigned overhead;
 130	ext4_fsblk_t metaend;
 131	struct buffer_head *bh = NULL;
 132	ext4_grpblk_t free_blocks_count, offset;
 133	int err = -EINVAL;
 134
 135	if (group != sbi->s_groups_count) {
 136		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 137			     input->group, sbi->s_groups_count);
 138		return -EINVAL;
 139	}
 140
 141	overhead = ext4_group_overhead_blocks(sb, group);
 142	metaend = start + overhead;
 143	free_blocks_count = input->blocks_count - 2 - overhead -
 144			    sbi->s_itb_per_group;
 145	input->free_clusters_count = EXT4_B2C(sbi, free_blocks_count);
 146
 147	if (test_opt(sb, DEBUG))
 148		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 149		       "(%d free, %u reserved)\n",
 150		       ext4_bg_has_super(sb, input->group) ? "normal" :
 151		       "no-super", input->group, input->blocks_count,
 152		       free_blocks_count, input->reserved_blocks);
 153
 154	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 155	if (offset != 0)
 156			ext4_warning(sb, "Last group not full");
 157	else if (input->reserved_blocks > input->blocks_count / 5)
 158		ext4_warning(sb, "Reserved blocks too high (%u)",
 159			     input->reserved_blocks);
 160	else if (free_blocks_count < 0)
 161		ext4_warning(sb, "Bad blocks count %u",
 162			     input->blocks_count);
 163	else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 164		err = PTR_ERR(bh);
 165		bh = NULL;
 166		ext4_warning(sb, "Cannot read last block (%llu)",
 167			     end - 1);
 168	} else if (outside(input->block_bitmap, start, end))
 169		ext4_warning(sb, "Block bitmap not in group (block %llu)",
 170			     (unsigned long long)input->block_bitmap);
 171	else if (outside(input->inode_bitmap, start, end))
 172		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 173			     (unsigned long long)input->inode_bitmap);
 174	else if (outside(input->inode_table, start, end) ||
 175		 outside(itend - 1, start, end))
 176		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 177			     (unsigned long long)input->inode_table, itend - 1);
 178	else if (input->inode_bitmap == input->block_bitmap)
 179		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 180			     (unsigned long long)input->block_bitmap);
 181	else if (inside(input->block_bitmap, input->inode_table, itend))
 182		ext4_warning(sb, "Block bitmap (%llu) in inode table "
 183			     "(%llu-%llu)",
 184			     (unsigned long long)input->block_bitmap,
 185			     (unsigned long long)input->inode_table, itend - 1);
 186	else if (inside(input->inode_bitmap, input->inode_table, itend))
 187		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 188			     "(%llu-%llu)",
 189			     (unsigned long long)input->inode_bitmap,
 190			     (unsigned long long)input->inode_table, itend - 1);
 191	else if (inside(input->block_bitmap, start, metaend))
 192		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 193			     (unsigned long long)input->block_bitmap,
 194			     start, metaend - 1);
 195	else if (inside(input->inode_bitmap, start, metaend))
 196		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 197			     (unsigned long long)input->inode_bitmap,
 198			     start, metaend - 1);
 199	else if (inside(input->inode_table, start, metaend) ||
 200		 inside(itend - 1, start, metaend))
 201		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 202			     "(%llu-%llu)",
 203			     (unsigned long long)input->inode_table,
 204			     itend - 1, start, metaend - 1);
 205	else
 206		err = 0;
 207	brelse(bh);
 208
 209	return err;
 210}
 211
 212/*
 213 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 214 * group each time.
 215 */
 216struct ext4_new_flex_group_data {
 217	struct ext4_new_group_data *groups;	/* new_group_data for groups
 218						   in the flex group */
 219	__u16 *bg_flags;			/* block group flags of groups
 220						   in @groups */
 221	ext4_group_t resize_bg;			/* number of allocated
 222						   new_group_data */
 223	ext4_group_t count;			/* number of groups in @groups
 224						 */
 225};
 226
 227/*
 228 * Avoiding memory allocation failures due to too many groups added each time.
 229 */
 230#define MAX_RESIZE_BG				16384
 231
 232/*
 233 * alloc_flex_gd() allocates an ext4_new_flex_group_data that satisfies the
 234 * resizing from @o_group to @n_group, its size is typically @flexbg_size.
 235 *
 236 * Returns NULL on failure otherwise address of the allocated structure.
 237 */
 238static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size,
 239				ext4_group_t o_group, ext4_group_t n_group)
 240{
 241	ext4_group_t last_group;
 242	unsigned int max_resize_bg;
 243	struct ext4_new_flex_group_data *flex_gd;
 244
 245	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 246	if (flex_gd == NULL)
 247		goto out3;
 248
 249	max_resize_bg = umin(flexbg_size, MAX_RESIZE_BG);
 250	flex_gd->resize_bg = max_resize_bg;
 251
 252	/* Avoid allocating large 'groups' array if not needed */
 253	last_group = o_group | (flex_gd->resize_bg - 1);
 254	if (n_group <= last_group)
 255		flex_gd->resize_bg = 1 << fls(n_group - o_group);
 256	else if (n_group - last_group < flex_gd->resize_bg)
 257		flex_gd->resize_bg = 1 << max(fls(last_group - o_group),
 258					      fls(n_group - last_group));
 259
 260	if (WARN_ON_ONCE(flex_gd->resize_bg > max_resize_bg))
 261		flex_gd->resize_bg = max_resize_bg;
 262
 263	flex_gd->groups = kmalloc_array(flex_gd->resize_bg,
 264					sizeof(struct ext4_new_group_data),
 265					GFP_NOFS);
 266	if (flex_gd->groups == NULL)
 267		goto out2;
 268
 269	flex_gd->bg_flags = kmalloc_array(flex_gd->resize_bg, sizeof(__u16),
 270					  GFP_NOFS);
 271	if (flex_gd->bg_flags == NULL)
 272		goto out1;
 273
 274	return flex_gd;
 275
 276out1:
 277	kfree(flex_gd->groups);
 278out2:
 279	kfree(flex_gd);
 280out3:
 281	return NULL;
 282}
 283
 284static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 285{
 286	kfree(flex_gd->bg_flags);
 287	kfree(flex_gd->groups);
 288	kfree(flex_gd);
 289}
 290
 291/*
 292 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 293 * and inode tables for a flex group.
 294 *
 295 * This function is used by 64bit-resize.  Note that this function allocates
 296 * group tables from the 1st group of groups contained by @flexgd, which may
 297 * be a partial of a flex group.
 298 *
 299 * @sb: super block of fs to which the groups belongs
 300 *
 301 * Returns 0 on a successful allocation of the metadata blocks in the
 302 * block group.
 303 */
 304static int ext4_alloc_group_tables(struct super_block *sb,
 305				struct ext4_new_flex_group_data *flex_gd,
 306				unsigned int flexbg_size)
 307{
 308	struct ext4_new_group_data *group_data = flex_gd->groups;
 309	ext4_fsblk_t start_blk;
 310	ext4_fsblk_t last_blk;
 311	ext4_group_t src_group;
 312	ext4_group_t bb_index = 0;
 313	ext4_group_t ib_index = 0;
 314	ext4_group_t it_index = 0;
 315	ext4_group_t group;
 316	ext4_group_t last_group;
 317	unsigned overhead;
 318	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 319	int i;
 320
 321	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 322
 323	src_group = group_data[0].group;
 324	last_group  = src_group + flex_gd->count - 1;
 325
 326	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 327	       (last_group & ~(flexbg_size - 1))));
 328next_group:
 329	group = group_data[0].group;
 330	if (src_group >= group_data[0].group + flex_gd->count)
 331		return -ENOSPC;
 332	start_blk = ext4_group_first_block_no(sb, src_group);
 333	last_blk = start_blk + group_data[src_group - group].blocks_count;
 334
 335	overhead = ext4_group_overhead_blocks(sb, src_group);
 336
 337	start_blk += overhead;
 338
 339	/* We collect contiguous blocks as much as possible. */
 340	src_group++;
 341	for (; src_group <= last_group; src_group++) {
 342		overhead = ext4_group_overhead_blocks(sb, src_group);
 343		if (overhead == 0)
 344			last_blk += group_data[src_group - group].blocks_count;
 345		else
 346			break;
 347	}
 348
 349	/* Allocate block bitmaps */
 350	for (; bb_index < flex_gd->count; bb_index++) {
 351		if (start_blk >= last_blk)
 352			goto next_group;
 353		group_data[bb_index].block_bitmap = start_blk++;
 354		group = ext4_get_group_number(sb, start_blk - 1);
 355		group -= group_data[0].group;
 356		group_data[group].mdata_blocks++;
 357		flex_gd->bg_flags[group] &= uninit_mask;
 358	}
 359
 360	/* Allocate inode bitmaps */
 361	for (; ib_index < flex_gd->count; ib_index++) {
 362		if (start_blk >= last_blk)
 363			goto next_group;
 364		group_data[ib_index].inode_bitmap = start_blk++;
 365		group = ext4_get_group_number(sb, start_blk - 1);
 366		group -= group_data[0].group;
 367		group_data[group].mdata_blocks++;
 368		flex_gd->bg_flags[group] &= uninit_mask;
 369	}
 370
 371	/* Allocate inode tables */
 372	for (; it_index < flex_gd->count; it_index++) {
 373		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 374		ext4_fsblk_t next_group_start;
 375
 376		if (start_blk + itb > last_blk)
 377			goto next_group;
 378		group_data[it_index].inode_table = start_blk;
 379		group = ext4_get_group_number(sb, start_blk);
 380		next_group_start = ext4_group_first_block_no(sb, group + 1);
 381		group -= group_data[0].group;
 382
 383		if (start_blk + itb > next_group_start) {
 384			flex_gd->bg_flags[group + 1] &= uninit_mask;
 385			overhead = start_blk + itb - next_group_start;
 386			group_data[group + 1].mdata_blocks += overhead;
 387			itb -= overhead;
 388		}
 389
 390		group_data[group].mdata_blocks += itb;
 391		flex_gd->bg_flags[group] &= uninit_mask;
 392		start_blk += EXT4_SB(sb)->s_itb_per_group;
 393	}
 394
 395	/* Update free clusters count to exclude metadata blocks */
 396	for (i = 0; i < flex_gd->count; i++) {
 397		group_data[i].free_clusters_count -=
 398				EXT4_NUM_B2C(EXT4_SB(sb),
 399					     group_data[i].mdata_blocks);
 400	}
 401
 402	if (test_opt(sb, DEBUG)) {
 403		int i;
 404		group = group_data[0].group;
 405
 406		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 407		       "%u groups, flexbg size is %u:\n", flex_gd->count,
 408		       flexbg_size);
 409
 410		for (i = 0; i < flex_gd->count; i++) {
 411			ext4_debug(
 412			       "adding %s group %u: %u blocks (%u free, %u mdata blocks)\n",
 413			       ext4_bg_has_super(sb, group + i) ? "normal" :
 414			       "no-super", group + i,
 415			       group_data[i].blocks_count,
 416			       group_data[i].free_clusters_count,
 417			       group_data[i].mdata_blocks);
 418		}
 419	}
 420	return 0;
 421}
 422
 423static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 424				  ext4_fsblk_t blk)
 425{
 426	struct buffer_head *bh;
 427	int err;
 428
 429	bh = sb_getblk(sb, blk);
 430	if (unlikely(!bh))
 431		return ERR_PTR(-ENOMEM);
 432	BUFFER_TRACE(bh, "get_write_access");
 433	err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
 434	if (err) {
 435		brelse(bh);
 436		bh = ERR_PTR(err);
 437	} else {
 438		memset(bh->b_data, 0, sb->s_blocksize);
 439		set_buffer_uptodate(bh);
 440	}
 441
 442	return bh;
 443}
 444
 445static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 446{
 447	return ext4_journal_ensure_credits_fn(handle, credits,
 448		EXT4_MAX_TRANS_DATA, 0, 0);
 449}
 450
 451/*
 452 * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 453 *
 454 * Helper function for ext4_setup_new_group_blocks() which set .
 455 *
 456 * @sb: super block
 457 * @handle: journal handle
 458 * @flex_gd: flex group data
 459 */
 460static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 461			struct ext4_new_flex_group_data *flex_gd,
 462			ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 463{
 464	struct ext4_sb_info *sbi = EXT4_SB(sb);
 465	ext4_group_t count = last_cluster - first_cluster + 1;
 466	ext4_group_t count2;
 467
 468	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 469		   last_cluster);
 470	for (; count > 0; count -= count2, first_cluster += count2) {
 
 471		ext4_fsblk_t start;
 472		struct buffer_head *bh;
 473		ext4_group_t group;
 474		int err;
 475
 476		group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 477		start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 478		group -= flex_gd->groups[0].group;
 479
 480		count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 481		if (count2 > count)
 482			count2 = count;
 483
 484		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 485			BUG_ON(flex_gd->count > 1);
 486			continue;
 487		}
 488
 489		err = ext4_resize_ensure_credits_batch(handle, 1);
 490		if (err < 0)
 491			return err;
 492
 493		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 494		if (unlikely(!bh))
 495			return -ENOMEM;
 496
 497		BUFFER_TRACE(bh, "get_write_access");
 498		err = ext4_journal_get_write_access(handle, sb, bh,
 499						    EXT4_JTR_NONE);
 500		if (err) {
 501			brelse(bh);
 502			return err;
 503		}
 504		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 505			   first_cluster, first_cluster - start, count2);
 506		mb_set_bits(bh->b_data, first_cluster - start, count2);
 507
 508		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 509		brelse(bh);
 510		if (unlikely(err))
 511			return err;
 512	}
 513
 514	return 0;
 515}
 516
 517/*
 518 * Set up the block and inode bitmaps, and the inode table for the new groups.
 519 * This doesn't need to be part of the main transaction, since we are only
 520 * changing blocks outside the actual filesystem.  We still do journaling to
 521 * ensure the recovery is correct in case of a failure just after resize.
 522 * If any part of this fails, we simply abort the resize.
 523 *
 524 * setup_new_flex_group_blocks handles a flex group as follow:
 525 *  1. copy super block and GDT, and initialize group tables if necessary.
 526 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 527 *     super block and GDT.
 528 *  2. allocate group tables in block bitmaps, that is, set bits in block
 529 *     bitmap for blocks taken by group tables.
 530 */
 531static int setup_new_flex_group_blocks(struct super_block *sb,
 532				struct ext4_new_flex_group_data *flex_gd)
 533{
 534	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 535	ext4_fsblk_t start;
 536	ext4_fsblk_t block;
 537	struct ext4_sb_info *sbi = EXT4_SB(sb);
 538	struct ext4_super_block *es = sbi->s_es;
 539	struct ext4_new_group_data *group_data = flex_gd->groups;
 540	__u16 *bg_flags = flex_gd->bg_flags;
 541	handle_t *handle;
 542	ext4_group_t group, count;
 543	struct buffer_head *bh = NULL;
 544	int reserved_gdb, i, j, err = 0, err2;
 545	int meta_bg;
 546
 547	BUG_ON(!flex_gd->count || !group_data ||
 548	       group_data[0].group != sbi->s_groups_count);
 549
 550	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 551	meta_bg = ext4_has_feature_meta_bg(sb);
 552
 553	/* This transaction may be extended/restarted along the way */
 554	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 555	if (IS_ERR(handle))
 556		return PTR_ERR(handle);
 557
 558	group = group_data[0].group;
 559	for (i = 0; i < flex_gd->count; i++, group++) {
 560		unsigned long gdblocks;
 561		ext4_grpblk_t overhead;
 562
 563		gdblocks = ext4_bg_num_gdb(sb, group);
 564		start = ext4_group_first_block_no(sb, group);
 565
 566		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 567			goto handle_itb;
 568
 569		if (meta_bg == 1)
 570			goto handle_itb;
 
 
 
 
 
 571
 572		block = start + ext4_bg_has_super(sb, group);
 573		/* Copy all of the GDT blocks into the backup in this group */
 574		for (j = 0; j < gdblocks; j++, block++) {
 575			struct buffer_head *gdb;
 576
 577			ext4_debug("update backup group %#04llx\n", block);
 578			err = ext4_resize_ensure_credits_batch(handle, 1);
 579			if (err < 0)
 580				goto out;
 581
 582			gdb = sb_getblk(sb, block);
 583			if (unlikely(!gdb)) {
 584				err = -ENOMEM;
 585				goto out;
 586			}
 587
 588			BUFFER_TRACE(gdb, "get_write_access");
 589			err = ext4_journal_get_write_access(handle, sb, gdb,
 590							    EXT4_JTR_NONE);
 591			if (err) {
 592				brelse(gdb);
 593				goto out;
 594			}
 595			memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
 596				s_group_desc, j)->b_data, gdb->b_size);
 597			set_buffer_uptodate(gdb);
 598
 599			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 600			if (unlikely(err)) {
 601				brelse(gdb);
 602				goto out;
 603			}
 604			brelse(gdb);
 605		}
 606
 607		/* Zero out all of the reserved backup group descriptor
 608		 * table blocks
 609		 */
 610		if (ext4_bg_has_super(sb, group)) {
 611			err = sb_issue_zeroout(sb, gdblocks + start + 1,
 612					reserved_gdb, GFP_NOFS);
 613			if (err)
 614				goto out;
 615		}
 616
 617handle_itb:
 618		/* Initialize group tables of the group @group */
 619		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 620			goto handle_bb;
 621
 622		/* Zero out all of the inode table blocks */
 623		block = group_data[i].inode_table;
 624		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 625			   block, sbi->s_itb_per_group);
 626		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 627				       GFP_NOFS);
 628		if (err)
 629			goto out;
 630
 631handle_bb:
 632		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 633			goto handle_ib;
 634
 635		/* Initialize block bitmap of the @group */
 636		block = group_data[i].block_bitmap;
 637		err = ext4_resize_ensure_credits_batch(handle, 1);
 638		if (err < 0)
 639			goto out;
 640
 641		bh = bclean(handle, sb, block);
 642		if (IS_ERR(bh)) {
 643			err = PTR_ERR(bh);
 644			goto out;
 645		}
 646		overhead = ext4_group_overhead_blocks(sb, group);
 647		if (overhead != 0) {
 648			ext4_debug("mark backup superblock %#04llx (+0)\n",
 649				   start);
 650			mb_set_bits(bh->b_data, 0,
 651				      EXT4_NUM_B2C(sbi, overhead));
 652		}
 653		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 654				     sb->s_blocksize * 8, bh->b_data);
 655		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 656		brelse(bh);
 657		if (err)
 658			goto out;
 659
 660handle_ib:
 661		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 662			continue;
 663
 664		/* Initialize inode bitmap of the @group */
 665		block = group_data[i].inode_bitmap;
 666		err = ext4_resize_ensure_credits_batch(handle, 1);
 667		if (err < 0)
 668			goto out;
 669		/* Mark unused entries in inode bitmap used */
 670		bh = bclean(handle, sb, block);
 671		if (IS_ERR(bh)) {
 672			err = PTR_ERR(bh);
 673			goto out;
 674		}
 675
 676		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 677				     sb->s_blocksize * 8, bh->b_data);
 678		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 679		brelse(bh);
 680		if (err)
 681			goto out;
 682	}
 683
 684	/* Mark group tables in block bitmap */
 685	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 686		count = group_table_count[j];
 687		start = (&group_data[0].block_bitmap)[j];
 688		block = start;
 689		for (i = 1; i < flex_gd->count; i++) {
 690			block += group_table_count[j];
 691			if (block == (&group_data[i].block_bitmap)[j]) {
 692				count += group_table_count[j];
 693				continue;
 694			}
 695			err = set_flexbg_block_bitmap(sb, handle,
 696						      flex_gd,
 697						      EXT4_B2C(sbi, start),
 698						      EXT4_B2C(sbi,
 699							       start + count
 700							       - 1));
 701			if (err)
 702				goto out;
 703			count = group_table_count[j];
 704			start = (&group_data[i].block_bitmap)[j];
 705			block = start;
 706		}
 707
 708		err = set_flexbg_block_bitmap(sb, handle,
 709				flex_gd,
 710				EXT4_B2C(sbi, start),
 711				EXT4_B2C(sbi,
 712					start + count
 713					- 1));
 714		if (err)
 715			goto out;
 
 
 716	}
 717
 718out:
 719	err2 = ext4_journal_stop(handle);
 720	if (err2 && !err)
 721		err = err2;
 722
 723	return err;
 724}
 725
 726/*
 727 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 728 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 729 * calling this for the first time.  In a sparse filesystem it will be the
 730 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 731 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 732 */
 733unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three,
 734			       unsigned int *five, unsigned int *seven)
 735{
 736	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 737	unsigned int *min = three;
 738	int mult = 3;
 739	unsigned int ret;
 740
 741	if (ext4_has_feature_sparse_super2(sb)) {
 742		do {
 743			if (*min > 2)
 744				return UINT_MAX;
 745			ret = le32_to_cpu(es->s_backup_bgs[*min - 1]);
 746			*min += 1;
 747		} while (!ret);
 748		return ret;
 749	}
 750
 751	if (!ext4_has_feature_sparse_super(sb)) {
 752		ret = *min;
 753		*min += 1;
 754		return ret;
 755	}
 756
 757	if (*five < *min) {
 758		min = five;
 759		mult = 5;
 760	}
 761	if (*seven < *min) {
 762		min = seven;
 763		mult = 7;
 764	}
 765
 766	ret = *min;
 767	*min *= mult;
 768
 769	return ret;
 770}
 771
 772/*
 773 * Check that all of the backup GDT blocks are held in the primary GDT block.
 774 * It is assumed that they are stored in group order.  Returns the number of
 775 * groups in current filesystem that have BACKUPS, or -ve error code.
 776 */
 777static int verify_reserved_gdb(struct super_block *sb,
 778			       ext4_group_t end,
 779			       struct buffer_head *primary)
 780{
 781	const ext4_fsblk_t blk = primary->b_blocknr;
 782	unsigned three = 1;
 783	unsigned five = 5;
 784	unsigned seven = 7;
 785	unsigned grp;
 786	__le32 *p = (__le32 *)primary->b_data;
 787	int gdbackups = 0;
 788
 789	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 790		if (le32_to_cpu(*p++) !=
 791		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 792			ext4_warning(sb, "reserved GDT %llu"
 793				     " missing grp %d (%llu)",
 794				     blk, grp,
 795				     grp *
 796				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 797				     blk);
 798			return -EINVAL;
 799		}
 800		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 801			return -EFBIG;
 802	}
 803
 804	return gdbackups;
 805}
 806
 807/*
 808 * Called when we need to bring a reserved group descriptor table block into
 809 * use from the resize inode.  The primary copy of the new GDT block currently
 810 * is an indirect block (under the double indirect block in the resize inode).
 811 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 812 * block, in group order.  Even though we know all the block numbers we need,
 813 * we check to ensure that the resize inode has actually reserved these blocks.
 814 *
 815 * Don't need to update the block bitmaps because the blocks are still in use.
 816 *
 817 * We get all of the error cases out of the way, so that we are sure to not
 818 * fail once we start modifying the data on disk, because JBD has no rollback.
 819 */
 820static int add_new_gdb(handle_t *handle, struct inode *inode,
 821		       ext4_group_t group)
 822{
 823	struct super_block *sb = inode->i_sb;
 824	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 825	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 826	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 827	struct buffer_head **o_group_desc, **n_group_desc = NULL;
 828	struct buffer_head *dind = NULL;
 829	struct buffer_head *gdb_bh = NULL;
 830	int gdbackups;
 831	struct ext4_iloc iloc = { .bh = NULL };
 832	__le32 *data;
 833	int err;
 834
 835	if (test_opt(sb, DEBUG))
 836		printk(KERN_DEBUG
 837		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 838		       gdb_num);
 839
 840	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 841	if (IS_ERR(gdb_bh))
 842		return PTR_ERR(gdb_bh);
 843
 844	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 845	if (gdbackups < 0) {
 846		err = gdbackups;
 847		goto errout;
 848	}
 849
 850	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 851	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 852	if (IS_ERR(dind)) {
 853		err = PTR_ERR(dind);
 854		dind = NULL;
 855		goto errout;
 856	}
 857
 858	data = (__le32 *)dind->b_data;
 859	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 860		ext4_warning(sb, "new group %u GDT block %llu not reserved",
 861			     group, gdblock);
 862		err = -EINVAL;
 863		goto errout;
 864	}
 865
 866	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 867	err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 868					    EXT4_JTR_NONE);
 869	if (unlikely(err))
 870		goto errout;
 871
 872	BUFFER_TRACE(gdb_bh, "get_write_access");
 873	err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 874	if (unlikely(err))
 875		goto errout;
 876
 877	BUFFER_TRACE(dind, "get_write_access");
 878	err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
 879	if (unlikely(err)) {
 880		ext4_std_error(sb, err);
 881		goto errout;
 882	}
 883
 884	/* ext4_reserve_inode_write() gets a reference on the iloc */
 885	err = ext4_reserve_inode_write(handle, inode, &iloc);
 886	if (unlikely(err))
 887		goto errout;
 888
 889	n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 890				GFP_KERNEL);
 891	if (!n_group_desc) {
 892		err = -ENOMEM;
 893		ext4_warning(sb, "not enough memory for %lu groups",
 894			     gdb_num + 1);
 895		goto errout;
 896	}
 897
 898	/*
 899	 * Finally, we have all of the possible failures behind us...
 900	 *
 901	 * Remove new GDT block from inode double-indirect block and clear out
 902	 * the new GDT block for use (which also "frees" the backup GDT blocks
 903	 * from the reserved inode).  We don't need to change the bitmaps for
 904	 * these blocks, because they are marked as in-use from being in the
 905	 * reserved inode, and will become GDT blocks (primary and backup).
 906	 */
 907	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 908	err = ext4_handle_dirty_metadata(handle, NULL, dind);
 909	if (unlikely(err)) {
 910		ext4_std_error(sb, err);
 911		goto errout;
 912	}
 913	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 914			   (9 - EXT4_SB(sb)->s_cluster_bits);
 915	ext4_mark_iloc_dirty(handle, inode, &iloc);
 916	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 917	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 918	if (unlikely(err)) {
 919		ext4_std_error(sb, err);
 920		iloc.bh = NULL;
 921		goto errout;
 922	}
 923	brelse(dind);
 924
 925	rcu_read_lock();
 926	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 927	memcpy(n_group_desc, o_group_desc,
 928	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 929	rcu_read_unlock();
 930	n_group_desc[gdb_num] = gdb_bh;
 931	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 932	EXT4_SB(sb)->s_gdb_count++;
 933	ext4_kvfree_array_rcu(o_group_desc);
 934
 935	lock_buffer(EXT4_SB(sb)->s_sbh);
 936	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 937	ext4_superblock_csum_set(sb);
 938	unlock_buffer(EXT4_SB(sb)->s_sbh);
 939	err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 940	if (err)
 941		ext4_std_error(sb, err);
 942	return err;
 943errout:
 944	kvfree(n_group_desc);
 945	brelse(iloc.bh);
 946	brelse(dind);
 947	brelse(gdb_bh);
 948
 949	ext4_debug("leaving with error %d\n", err);
 950	return err;
 951}
 952
 953/*
 954 * If there is no available space in the existing block group descriptors for
 955 * the new block group and there are no reserved block group descriptors, then
 956 * the meta_bg feature will get enabled, and es->s_first_meta_bg will get set
 957 * to the first block group that is managed using meta_bg and s_first_meta_bg
 958 * must be a multiple of EXT4_DESC_PER_BLOCK(sb).
 959 * This function will be called when first group of meta_bg is added to bring
 960 * new group descriptors block of new added meta_bg.
 961 */
 962static int add_new_gdb_meta_bg(struct super_block *sb,
 963			       handle_t *handle, ext4_group_t group) {
 964	ext4_fsblk_t gdblock;
 965	struct buffer_head *gdb_bh;
 966	struct buffer_head **o_group_desc, **n_group_desc;
 967	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 968	int err;
 969
 970	gdblock = ext4_group_first_block_no(sb, group) +
 971		  ext4_bg_has_super(sb, group);
 972	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 973	if (IS_ERR(gdb_bh))
 974		return PTR_ERR(gdb_bh);
 975	n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 976				GFP_KERNEL);
 977	if (!n_group_desc) {
 978		brelse(gdb_bh);
 979		err = -ENOMEM;
 980		ext4_warning(sb, "not enough memory for %lu groups",
 981			     gdb_num + 1);
 982		return err;
 983	}
 984
 985	rcu_read_lock();
 986	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 987	memcpy(n_group_desc, o_group_desc,
 988	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 989	rcu_read_unlock();
 990	n_group_desc[gdb_num] = gdb_bh;
 991
 992	BUFFER_TRACE(gdb_bh, "get_write_access");
 993	err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 994	if (err) {
 995		kvfree(n_group_desc);
 996		brelse(gdb_bh);
 997		return err;
 998	}
 999
1000	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
1001	EXT4_SB(sb)->s_gdb_count++;
1002	ext4_kvfree_array_rcu(o_group_desc);
1003	return err;
1004}
1005
1006/*
1007 * Called when we are adding a new group which has a backup copy of each of
1008 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
1009 * We need to add these reserved backup GDT blocks to the resize inode, so
1010 * that they are kept for future resizing and not allocated to files.
1011 *
1012 * Each reserved backup GDT block will go into a different indirect block.
1013 * The indirect blocks are actually the primary reserved GDT blocks,
1014 * so we know in advance what their block numbers are.  We only get the
1015 * double-indirect block to verify it is pointing to the primary reserved
1016 * GDT blocks so we don't overwrite a data block by accident.  The reserved
1017 * backup GDT blocks are stored in their reserved primary GDT block.
1018 */
1019static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1020			      ext4_group_t group)
1021{
1022	struct super_block *sb = inode->i_sb;
1023	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1024	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1025	struct buffer_head **primary;
1026	struct buffer_head *dind;
1027	struct ext4_iloc iloc;
1028	ext4_fsblk_t blk;
1029	__le32 *data, *end;
1030	int gdbackups = 0;
1031	int res, i;
1032	int err;
1033
1034	primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1035	if (!primary)
1036		return -ENOMEM;
1037
1038	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1039	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1040	if (IS_ERR(dind)) {
1041		err = PTR_ERR(dind);
1042		dind = NULL;
1043		goto exit_free;
1044	}
1045
1046	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1047	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1048					 EXT4_ADDR_PER_BLOCK(sb));
1049	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1050
1051	/* Get each reserved primary GDT block and verify it holds backups */
1052	for (res = 0; res < reserved_gdb; res++, blk++) {
1053		if (le32_to_cpu(*data) != blk) {
1054			ext4_warning(sb, "reserved block %llu"
1055				     " not at offset %ld",
1056				     blk,
1057				     (long)(data - (__le32 *)dind->b_data));
1058			err = -EINVAL;
1059			goto exit_bh;
1060		}
1061		primary[res] = ext4_sb_bread(sb, blk, 0);
1062		if (IS_ERR(primary[res])) {
1063			err = PTR_ERR(primary[res]);
1064			primary[res] = NULL;
1065			goto exit_bh;
1066		}
1067		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1068		if (gdbackups < 0) {
1069			brelse(primary[res]);
1070			err = gdbackups;
1071			goto exit_bh;
1072		}
1073		if (++data >= end)
1074			data = (__le32 *)dind->b_data;
1075	}
1076
1077	for (i = 0; i < reserved_gdb; i++) {
1078		BUFFER_TRACE(primary[i], "get_write_access");
1079		if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1080							 EXT4_JTR_NONE)))
1081			goto exit_bh;
1082	}
1083
1084	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1085		goto exit_bh;
1086
1087	/*
1088	 * Finally we can add each of the reserved backup GDT blocks from
1089	 * the new group to its reserved primary GDT block.
1090	 */
1091	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1092	for (i = 0; i < reserved_gdb; i++) {
1093		int err2;
1094		data = (__le32 *)primary[i]->b_data;
 
 
 
1095		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1096		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1097		if (!err)
1098			err = err2;
1099	}
1100
1101	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1102	ext4_mark_iloc_dirty(handle, inode, &iloc);
1103
1104exit_bh:
1105	while (--res >= 0)
1106		brelse(primary[res]);
1107	brelse(dind);
1108
1109exit_free:
1110	kfree(primary);
1111
1112	return err;
1113}
1114
1115static inline void ext4_set_block_group_nr(struct super_block *sb, char *data,
1116					   ext4_group_t group)
1117{
1118	struct ext4_super_block *es = (struct ext4_super_block *) data;
1119
1120	es->s_block_group_nr = cpu_to_le16(group);
1121	if (ext4_has_metadata_csum(sb))
1122		es->s_checksum = ext4_superblock_csum(sb, es);
1123}
1124
1125/*
1126 * Update the backup copies of the ext4 metadata.  These don't need to be part
1127 * of the main resize transaction, because e2fsck will re-write them if there
1128 * is a problem (basically only OOM will cause a problem).  However, we
1129 * _should_ update the backups if possible, in case the primary gets trashed
1130 * for some reason and we need to run e2fsck from a backup superblock.  The
1131 * important part is that the new block and inode counts are in the backup
1132 * superblocks, and the location of the new group metadata in the GDT backups.
1133 *
1134 * We do not need take the s_resize_lock for this, because these
1135 * blocks are not otherwise touched by the filesystem code when it is
1136 * mounted.  We don't need to worry about last changing from
1137 * sbi->s_groups_count, because the worst that can happen is that we
1138 * do not copy the full number of backups at this time.  The resize
1139 * which changed s_groups_count will backup again.
1140 */
1141static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1142			   int size, int meta_bg)
1143{
1144	struct ext4_sb_info *sbi = EXT4_SB(sb);
1145	ext4_group_t last;
1146	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1147	unsigned three = 1;
1148	unsigned five = 5;
1149	unsigned seven = 7;
1150	ext4_group_t group = 0;
1151	int rest = sb->s_blocksize - size;
1152	handle_t *handle;
1153	int err = 0, err2;
1154
1155	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1156	if (IS_ERR(handle)) {
1157		group = 1;
1158		err = PTR_ERR(handle);
1159		goto exit_err;
1160	}
1161
1162	if (meta_bg == 0) {
1163		group = ext4_list_backups(sb, &three, &five, &seven);
1164		last = sbi->s_groups_count;
1165	} else {
1166		group = ext4_get_group_number(sb, blk_off) + 1;
1167		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1168	}
1169
1170	while (group < sbi->s_groups_count) {
1171		struct buffer_head *bh;
1172		ext4_fsblk_t backup_block;
1173		int has_super = ext4_bg_has_super(sb, group);
1174		ext4_fsblk_t first_block = ext4_group_first_block_no(sb, group);
1175
1176		/* Out of journal space, and can't get more - abort - so sad */
1177		err = ext4_resize_ensure_credits_batch(handle, 1);
1178		if (err < 0)
1179			break;
1180
1181		if (meta_bg == 0)
1182			backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1183		else
1184			backup_block = first_block + has_super;
 
1185
1186		bh = sb_getblk(sb, backup_block);
1187		if (unlikely(!bh)) {
1188			err = -ENOMEM;
1189			break;
1190		}
1191		ext4_debug("update metadata backup %llu(+%llu)\n",
1192			   backup_block, backup_block -
1193			   ext4_group_first_block_no(sb, group));
1194		BUFFER_TRACE(bh, "get_write_access");
1195		if ((err = ext4_journal_get_write_access(handle, sb, bh,
1196							 EXT4_JTR_NONE))) {
1197			brelse(bh);
1198			break;
1199		}
1200		lock_buffer(bh);
1201		memcpy(bh->b_data, data, size);
1202		if (rest)
1203			memset(bh->b_data + size, 0, rest);
1204		if (has_super && (backup_block == first_block))
1205			ext4_set_block_group_nr(sb, bh->b_data, group);
1206		set_buffer_uptodate(bh);
1207		unlock_buffer(bh);
1208		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1209		if (unlikely(err))
1210			ext4_std_error(sb, err);
1211		brelse(bh);
1212
1213		if (meta_bg == 0)
1214			group = ext4_list_backups(sb, &three, &five, &seven);
1215		else if (group == last)
1216			break;
1217		else
1218			group = last;
1219	}
1220	if ((err2 = ext4_journal_stop(handle)) && !err)
1221		err = err2;
1222
1223	/*
1224	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1225	 * late to revert the resize, we shouldn't fail just because of
1226	 * the backup copies (they are only needed in case of corruption).
1227	 *
1228	 * However, if we got here we have a journal problem too, so we
1229	 * can't really start a transaction to mark the superblock.
1230	 * Chicken out and just set the flag on the hope it will be written
1231	 * to disk, and if not - we will simply wait until next fsck.
1232	 */
1233exit_err:
1234	if (err) {
1235		ext4_warning(sb, "can't update backup for group %u (err %d), "
1236			     "forcing fsck on next reboot", group, err);
1237		sbi->s_mount_state &= ~EXT4_VALID_FS;
1238		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1239		mark_buffer_dirty(sbi->s_sbh);
1240	}
1241}
1242
1243/*
1244 * ext4_add_new_descs() adds @count group descriptor of groups
1245 * starting at @group
1246 *
1247 * @handle: journal handle
1248 * @sb: super block
1249 * @group: the group no. of the first group desc to be added
1250 * @resize_inode: the resize inode
1251 * @count: number of group descriptors to be added
1252 */
1253static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1254			      ext4_group_t group, struct inode *resize_inode,
1255			      ext4_group_t count)
1256{
1257	struct ext4_sb_info *sbi = EXT4_SB(sb);
1258	struct ext4_super_block *es = sbi->s_es;
1259	struct buffer_head *gdb_bh;
1260	int i, gdb_off, gdb_num, err = 0;
1261	int meta_bg;
1262
1263	meta_bg = ext4_has_feature_meta_bg(sb);
1264	for (i = 0; i < count; i++, group++) {
1265		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1266			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1267
1268		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1269		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1270
1271		/*
1272		 * We will only either add reserved group blocks to a backup group
1273		 * or remove reserved blocks for the first group in a new group block.
1274		 * Doing both would be mean more complex code, and sane people don't
1275		 * use non-sparse filesystems anymore.  This is already checked above.
1276		 */
1277		if (gdb_off) {
1278			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1279						     gdb_num);
1280			BUFFER_TRACE(gdb_bh, "get_write_access");
1281			err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1282							    EXT4_JTR_NONE);
1283
1284			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1285				err = reserve_backup_gdb(handle, resize_inode, group);
1286		} else if (meta_bg != 0) {
1287			err = add_new_gdb_meta_bg(sb, handle, group);
1288		} else {
1289			err = add_new_gdb(handle, resize_inode, group);
1290		}
1291		if (err)
1292			break;
1293	}
1294	return err;
1295}
1296
1297static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1298{
1299	struct buffer_head *bh = sb_getblk(sb, block);
1300	if (unlikely(!bh))
1301		return NULL;
1302	if (!bh_uptodate_or_lock(bh)) {
1303		if (ext4_read_bh(bh, 0, NULL, false) < 0) {
1304			brelse(bh);
1305			return NULL;
1306		}
1307	}
1308
1309	return bh;
1310}
1311
1312static int ext4_set_bitmap_checksums(struct super_block *sb,
 
1313				     struct ext4_group_desc *gdp,
1314				     struct ext4_new_group_data *group_data)
1315{
1316	struct buffer_head *bh;
1317
1318	if (!ext4_has_metadata_csum(sb))
1319		return 0;
1320
1321	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1322	if (!bh)
1323		return -EIO;
1324	ext4_inode_bitmap_csum_set(sb, gdp, bh);
 
1325	brelse(bh);
1326
1327	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1328	if (!bh)
1329		return -EIO;
1330	ext4_block_bitmap_csum_set(sb, gdp, bh);
1331	brelse(bh);
1332
1333	return 0;
1334}
1335
1336/*
1337 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1338 */
1339static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1340				struct ext4_new_flex_group_data *flex_gd)
1341{
1342	struct ext4_new_group_data	*group_data = flex_gd->groups;
1343	struct ext4_group_desc		*gdp;
1344	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1345	struct buffer_head		*gdb_bh;
1346	ext4_group_t			group;
1347	__u16				*bg_flags = flex_gd->bg_flags;
1348	int				i, gdb_off, gdb_num, err = 0;
1349
1350
1351	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1352		group = group_data->group;
1353
1354		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1355		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1356
1357		/*
1358		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1359		 */
1360		gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1361		/* Update group descriptor block for new group */
1362		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1363						 gdb_off * EXT4_DESC_SIZE(sb));
1364
1365		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1366		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1367		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1368		err = ext4_set_bitmap_checksums(sb, gdp, group_data);
1369		if (err) {
1370			ext4_std_error(sb, err);
1371			break;
1372		}
1373
1374		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1375		ext4_free_group_clusters_set(sb, gdp,
1376					     group_data->free_clusters_count);
1377		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1378		if (ext4_has_group_desc_csum(sb))
1379			ext4_itable_unused_set(sb, gdp,
1380					       EXT4_INODES_PER_GROUP(sb));
1381		gdp->bg_flags = cpu_to_le16(*bg_flags);
1382		ext4_group_desc_csum_set(sb, group, gdp);
1383
1384		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1385		if (unlikely(err)) {
1386			ext4_std_error(sb, err);
1387			break;
1388		}
1389
1390		/*
1391		 * We can allocate memory for mb_alloc based on the new group
1392		 * descriptor
1393		 */
1394		err = ext4_mb_add_groupinfo(sb, group, gdp);
1395		if (err)
1396			break;
1397	}
1398	return err;
1399}
1400
1401static void ext4_add_overhead(struct super_block *sb,
1402                              const ext4_fsblk_t overhead)
1403{
1404       struct ext4_sb_info *sbi = EXT4_SB(sb);
1405       struct ext4_super_block *es = sbi->s_es;
1406
1407       sbi->s_overhead += overhead;
1408       es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1409       smp_wmb();
1410}
1411
1412/*
1413 * ext4_update_super() updates the super block so that the newly added
1414 * groups can be seen by the filesystem.
1415 *
1416 * @sb: super block
1417 * @flex_gd: new added groups
1418 */
1419static void ext4_update_super(struct super_block *sb,
1420			     struct ext4_new_flex_group_data *flex_gd)
1421{
1422	ext4_fsblk_t blocks_count = 0;
1423	ext4_fsblk_t free_blocks = 0;
1424	ext4_fsblk_t reserved_blocks = 0;
1425	struct ext4_new_group_data *group_data = flex_gd->groups;
1426	struct ext4_sb_info *sbi = EXT4_SB(sb);
1427	struct ext4_super_block *es = sbi->s_es;
1428	int i;
1429
1430	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1431	/*
1432	 * Make the new blocks and inodes valid next.  We do this before
1433	 * increasing the group count so that once the group is enabled,
1434	 * all of its blocks and inodes are already valid.
1435	 *
1436	 * We always allocate group-by-group, then block-by-block or
1437	 * inode-by-inode within a group, so enabling these
1438	 * blocks/inodes before the group is live won't actually let us
1439	 * allocate the new space yet.
1440	 */
1441	for (i = 0; i < flex_gd->count; i++) {
1442		blocks_count += group_data[i].blocks_count;
1443		free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1444	}
1445
1446	reserved_blocks = ext4_r_blocks_count(es) * 100;
1447	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1448	reserved_blocks *= blocks_count;
1449	do_div(reserved_blocks, 100);
1450
1451	lock_buffer(sbi->s_sbh);
1452	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1453	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1454	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1455		     flex_gd->count);
1456	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1457		     flex_gd->count);
1458
1459	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1460	/*
1461	 * We need to protect s_groups_count against other CPUs seeing
1462	 * inconsistent state in the superblock.
1463	 *
1464	 * The precise rules we use are:
1465	 *
1466	 * * Writers must perform a smp_wmb() after updating all
1467	 *   dependent data and before modifying the groups count
1468	 *
1469	 * * Readers must perform an smp_rmb() after reading the groups
1470	 *   count and before reading any dependent data.
1471	 *
1472	 * NB. These rules can be relaxed when checking the group count
1473	 * while freeing data, as we can only allocate from a block
1474	 * group after serialising against the group count, and we can
1475	 * only then free after serialising in turn against that
1476	 * allocation.
1477	 */
1478	smp_wmb();
1479
1480	/* Update the global fs size fields */
1481	sbi->s_groups_count += flex_gd->count;
1482	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1483			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1484
1485	/* Update the reserved block counts only once the new group is
1486	 * active. */
1487	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1488				reserved_blocks);
1489
1490	/* Update the free space counts */
1491	percpu_counter_add(&sbi->s_freeclusters_counter,
1492			   EXT4_NUM_B2C(sbi, free_blocks));
1493	percpu_counter_add(&sbi->s_freeinodes_counter,
1494			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1495
1496	ext4_debug("free blocks count %llu",
1497		   percpu_counter_read(&sbi->s_freeclusters_counter));
1498	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1499		ext4_group_t flex_group;
1500		struct flex_groups *fg;
1501
1502		flex_group = ext4_flex_group(sbi, group_data[0].group);
1503		fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1504		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1505			     &fg->free_clusters);
1506		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1507			   &fg->free_inodes);
1508	}
1509
1510	/*
1511	 * Update the fs overhead information.
1512	 *
1513	 * For bigalloc, if the superblock already has a properly calculated
1514	 * overhead, update it with a value based on numbers already computed
1515	 * above for the newly allocated capacity.
1516	 */
1517	if (ext4_has_feature_bigalloc(sb) && (sbi->s_overhead != 0))
1518		ext4_add_overhead(sb,
1519			EXT4_NUM_B2C(sbi, blocks_count - free_blocks));
1520	else
1521		ext4_calculate_overhead(sb);
1522	es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1523
1524	ext4_superblock_csum_set(sb);
1525	unlock_buffer(sbi->s_sbh);
1526	if (test_opt(sb, DEBUG))
1527		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1528		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1529		       blocks_count, free_blocks, reserved_blocks);
1530}
1531
1532/* Add a flex group to an fs. Ensure we handle all possible error conditions
1533 * _before_ we start modifying the filesystem, because we cannot abort the
1534 * transaction and not have it write the data to disk.
1535 */
1536static int ext4_flex_group_add(struct super_block *sb,
1537			       struct inode *resize_inode,
1538			       struct ext4_new_flex_group_data *flex_gd)
1539{
1540	struct ext4_sb_info *sbi = EXT4_SB(sb);
1541	struct ext4_super_block *es = sbi->s_es;
1542	ext4_fsblk_t o_blocks_count;
1543	ext4_grpblk_t last;
1544	ext4_group_t group;
1545	handle_t *handle;
1546	unsigned reserved_gdb;
1547	int err = 0, err2 = 0, credit;
1548
1549	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1550
1551	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1552	o_blocks_count = ext4_blocks_count(es);
1553	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1554	BUG_ON(last);
1555
1556	err = setup_new_flex_group_blocks(sb, flex_gd);
1557	if (err)
1558		goto exit;
1559	/*
1560	 * We will always be modifying at least the superblock and  GDT
1561	 * blocks.  If we are adding a group past the last current GDT block,
1562	 * we will also modify the inode and the dindirect block.  If we
1563	 * are adding a group with superblock/GDT backups  we will also
1564	 * modify each of the reserved GDT dindirect blocks.
1565	 */
1566	credit = 3;	/* sb, resize inode, resize inode dindirect */
1567	/* GDT blocks */
1568	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1569	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
1570	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1571	if (IS_ERR(handle)) {
1572		err = PTR_ERR(handle);
1573		goto exit;
1574	}
1575
1576	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1577	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1578					    EXT4_JTR_NONE);
1579	if (err)
1580		goto exit_journal;
1581
1582	group = flex_gd->groups[0].group;
1583	BUG_ON(group != sbi->s_groups_count);
1584	err = ext4_add_new_descs(handle, sb, group,
1585				resize_inode, flex_gd->count);
1586	if (err)
1587		goto exit_journal;
1588
1589	err = ext4_setup_new_descs(handle, sb, flex_gd);
1590	if (err)
1591		goto exit_journal;
1592
1593	ext4_update_super(sb, flex_gd);
1594
1595	err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1596
1597exit_journal:
1598	err2 = ext4_journal_stop(handle);
1599	if (!err)
1600		err = err2;
1601
1602	if (!err) {
1603		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1604		int gdb_num_end = ((group + flex_gd->count - 1) /
1605				   EXT4_DESC_PER_BLOCK(sb));
1606		int meta_bg = ext4_has_feature_meta_bg(sb) &&
1607			      gdb_num >= le32_to_cpu(es->s_first_meta_bg);
1608		sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
1609					 ext4_group_first_block_no(sb, 0);
1610
1611		update_backups(sb, ext4_group_first_block_no(sb, 0),
1612			       (char *)es, sizeof(struct ext4_super_block), 0);
1613		for (; gdb_num <= gdb_num_end; gdb_num++) {
1614			struct buffer_head *gdb_bh;
1615
1616			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1617						     gdb_num);
1618			update_backups(sb, gdb_bh->b_blocknr - padding_blocks,
1619				       gdb_bh->b_data, gdb_bh->b_size, meta_bg);
 
 
 
1620		}
1621	}
1622exit:
1623	return err;
1624}
1625
1626static int ext4_setup_next_flex_gd(struct super_block *sb,
1627				    struct ext4_new_flex_group_data *flex_gd,
1628				    ext4_fsblk_t n_blocks_count)
 
1629{
1630	struct ext4_sb_info *sbi = EXT4_SB(sb);
1631	struct ext4_super_block *es = sbi->s_es;
1632	struct ext4_new_group_data *group_data = flex_gd->groups;
1633	ext4_fsblk_t o_blocks_count;
1634	ext4_group_t n_group;
1635	ext4_group_t group;
1636	ext4_group_t last_group;
1637	ext4_grpblk_t last;
1638	ext4_grpblk_t clusters_per_group;
1639	unsigned long i;
1640
1641	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1642
1643	o_blocks_count = ext4_blocks_count(es);
1644
1645	if (o_blocks_count == n_blocks_count)
1646		return 0;
1647
1648	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1649	BUG_ON(last);
1650	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1651
1652	last_group = group | (flex_gd->resize_bg - 1);
1653	if (last_group > n_group)
1654		last_group = n_group;
1655
1656	flex_gd->count = last_group - group + 1;
1657
1658	for (i = 0; i < flex_gd->count; i++) {
1659		int overhead;
1660
1661		group_data[i].group = group + i;
1662		group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1663		overhead = ext4_group_overhead_blocks(sb, group + i);
1664		group_data[i].mdata_blocks = overhead;
1665		group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1666		if (ext4_has_group_desc_csum(sb)) {
1667			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1668					       EXT4_BG_INODE_UNINIT;
1669			if (!test_opt(sb, INIT_INODE_TABLE))
1670				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1671		} else
1672			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1673	}
1674
1675	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1676		/* We need to initialize block bitmap of last group. */
1677		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1678
1679	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1680		group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1681		group_data[i - 1].free_clusters_count -= clusters_per_group -
1682						       last - 1;
1683	}
1684
1685	return 1;
1686}
1687
1688/* Add group descriptor data to an existing or new group descriptor block.
1689 * Ensure we handle all possible error conditions _before_ we start modifying
1690 * the filesystem, because we cannot abort the transaction and not have it
1691 * write the data to disk.
1692 *
1693 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1694 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1695 *
1696 * We only need to hold the superblock lock while we are actually adding
1697 * in the new group's counts to the superblock.  Prior to that we have
1698 * not really "added" the group at all.  We re-check that we are still
1699 * adding in the last group in case things have changed since verifying.
1700 */
1701int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1702{
1703	struct ext4_new_flex_group_data flex_gd;
1704	struct ext4_sb_info *sbi = EXT4_SB(sb);
1705	struct ext4_super_block *es = sbi->s_es;
1706	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1707		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1708	struct inode *inode = NULL;
1709	int gdb_off;
1710	int err;
1711	__u16 bg_flags = 0;
1712
1713	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1714
1715	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1716		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1717		return -EPERM;
1718	}
1719
1720	if (ext4_blocks_count(es) + input->blocks_count <
1721	    ext4_blocks_count(es)) {
1722		ext4_warning(sb, "blocks_count overflow");
1723		return -EINVAL;
1724	}
1725
1726	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1727	    le32_to_cpu(es->s_inodes_count)) {
1728		ext4_warning(sb, "inodes_count overflow");
1729		return -EINVAL;
1730	}
1731
1732	if (reserved_gdb || gdb_off == 0) {
1733		if (!ext4_has_feature_resize_inode(sb) ||
1734		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1735			ext4_warning(sb,
1736				     "No reserved GDT blocks, can't resize");
1737			return -EPERM;
1738		}
1739		inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1740		if (IS_ERR(inode)) {
1741			ext4_warning(sb, "Error opening resize inode");
1742			return PTR_ERR(inode);
1743		}
1744	}
1745
1746
1747	err = verify_group_input(sb, input);
1748	if (err)
1749		goto out;
1750
1751	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1752	if (err)
1753		goto out;
1754
1755	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1756	if (err)
1757		goto out;
1758
1759	flex_gd.count = 1;
1760	flex_gd.groups = input;
1761	flex_gd.bg_flags = &bg_flags;
1762	err = ext4_flex_group_add(sb, inode, &flex_gd);
1763out:
1764	iput(inode);
1765	return err;
1766} /* ext4_group_add */
1767
1768/*
1769 * extend a group without checking assuming that checking has been done.
1770 */
1771static int ext4_group_extend_no_check(struct super_block *sb,
1772				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1773{
1774	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1775	handle_t *handle;
1776	int err = 0, err2;
1777
1778	/* We will update the superblock, one block bitmap, and
1779	 * one group descriptor via ext4_group_add_blocks().
1780	 */
1781	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1782	if (IS_ERR(handle)) {
1783		err = PTR_ERR(handle);
1784		ext4_warning(sb, "error %d on journal start", err);
1785		return err;
1786	}
1787
1788	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1789	err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1790					    EXT4_JTR_NONE);
1791	if (err) {
1792		ext4_warning(sb, "error %d on journal write access", err);
1793		goto errout;
1794	}
1795
1796	lock_buffer(EXT4_SB(sb)->s_sbh);
1797	ext4_blocks_count_set(es, o_blocks_count + add);
1798	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1799	ext4_superblock_csum_set(sb);
1800	unlock_buffer(EXT4_SB(sb)->s_sbh);
1801	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1802		   o_blocks_count + add);
1803	/* We add the blocks to the bitmap and set the group need init bit */
1804	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1805	if (err)
1806		goto errout;
1807	ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1808	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1809		   o_blocks_count + add);
1810errout:
1811	err2 = ext4_journal_stop(handle);
1812	if (err2 && !err)
1813		err = err2;
1814
1815	if (!err) {
1816		if (test_opt(sb, DEBUG))
1817			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1818			       "blocks\n", ext4_blocks_count(es));
1819		update_backups(sb, ext4_group_first_block_no(sb, 0),
1820			       (char *)es, sizeof(struct ext4_super_block), 0);
1821	}
1822	return err;
1823}
1824
1825/*
1826 * Extend the filesystem to the new number of blocks specified.  This entry
1827 * point is only used to extend the current filesystem to the end of the last
1828 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1829 * for emergencies (because it has no dependencies on reserved blocks).
1830 *
1831 * If we _really_ wanted, we could use default values to call ext4_group_add()
1832 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1833 * GDT blocks are reserved to grow to the desired size.
1834 */
1835int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1836		      ext4_fsblk_t n_blocks_count)
1837{
1838	ext4_fsblk_t o_blocks_count;
1839	ext4_grpblk_t last;
1840	ext4_grpblk_t add;
1841	struct buffer_head *bh;
 
1842	ext4_group_t group;
1843
1844	o_blocks_count = ext4_blocks_count(es);
1845
1846	if (test_opt(sb, DEBUG))
1847		ext4_msg(sb, KERN_DEBUG,
1848			 "extending last group from %llu to %llu blocks",
1849			 o_blocks_count, n_blocks_count);
1850
1851	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1852		return 0;
1853
1854	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1855		ext4_msg(sb, KERN_ERR,
1856			 "filesystem too large to resize to %llu blocks safely",
1857			 n_blocks_count);
1858		return -EINVAL;
1859	}
1860
1861	if (n_blocks_count < o_blocks_count) {
1862		ext4_warning(sb, "can't shrink FS - resize aborted");
1863		return -EINVAL;
1864	}
1865
1866	/* Handle the remaining blocks in the last group only. */
1867	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1868
1869	if (last == 0) {
1870		ext4_warning(sb, "need to use ext2online to resize further");
1871		return -EPERM;
1872	}
1873
1874	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1875
1876	if (o_blocks_count + add < o_blocks_count) {
1877		ext4_warning(sb, "blocks_count overflow");
1878		return -EINVAL;
1879	}
1880
1881	if (o_blocks_count + add > n_blocks_count)
1882		add = n_blocks_count - o_blocks_count;
1883
1884	if (o_blocks_count + add < n_blocks_count)
1885		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1886			     o_blocks_count + add, add);
1887
1888	/* See if the device is actually as big as what was requested */
1889	bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1890	if (IS_ERR(bh)) {
1891		ext4_warning(sb, "can't read last block, resize aborted");
1892		return -ENOSPC;
1893	}
1894	brelse(bh);
1895
1896	return ext4_group_extend_no_check(sb, o_blocks_count, add);
 
1897} /* ext4_group_extend */
1898
1899
1900static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1901{
1902	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1903}
1904
1905/*
1906 * Release the resize inode and drop the resize_inode feature if there
1907 * are no more reserved gdt blocks, and then convert the file system
1908 * to enable meta_bg
1909 */
1910static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1911{
1912	handle_t *handle;
1913	struct ext4_sb_info *sbi = EXT4_SB(sb);
1914	struct ext4_super_block *es = sbi->s_es;
1915	struct ext4_inode_info *ei = EXT4_I(inode);
1916	ext4_fsblk_t nr;
1917	int i, ret, err = 0;
1918	int credits = 1;
1919
1920	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1921	if (inode) {
1922		if (es->s_reserved_gdt_blocks) {
1923			ext4_error(sb, "Unexpected non-zero "
1924				   "s_reserved_gdt_blocks");
1925			return -EPERM;
1926		}
1927
1928		/* Do a quick sanity check of the resize inode */
1929		if (inode->i_blocks != 1 << (inode->i_blkbits -
1930					     (9 - sbi->s_cluster_bits)))
1931			goto invalid_resize_inode;
1932		for (i = 0; i < EXT4_N_BLOCKS; i++) {
1933			if (i == EXT4_DIND_BLOCK) {
1934				if (ei->i_data[i])
1935					continue;
1936				else
1937					goto invalid_resize_inode;
1938			}
1939			if (ei->i_data[i])
1940				goto invalid_resize_inode;
1941		}
1942		credits += 3;	/* block bitmap, bg descriptor, resize inode */
1943	}
1944
1945	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1946	if (IS_ERR(handle))
1947		return PTR_ERR(handle);
1948
1949	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1950	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1951					    EXT4_JTR_NONE);
1952	if (err)
1953		goto errout;
1954
1955	lock_buffer(sbi->s_sbh);
1956	ext4_clear_feature_resize_inode(sb);
1957	ext4_set_feature_meta_bg(sb);
1958	sbi->s_es->s_first_meta_bg =
1959		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1960	ext4_superblock_csum_set(sb);
1961	unlock_buffer(sbi->s_sbh);
1962
1963	err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1964	if (err) {
1965		ext4_std_error(sb, err);
1966		goto errout;
1967	}
1968
1969	if (inode) {
1970		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1971		ext4_free_blocks(handle, inode, NULL, nr, 1,
1972				 EXT4_FREE_BLOCKS_METADATA |
1973				 EXT4_FREE_BLOCKS_FORGET);
1974		ei->i_data[EXT4_DIND_BLOCK] = 0;
1975		inode->i_blocks = 0;
1976
1977		err = ext4_mark_inode_dirty(handle, inode);
1978		if (err)
1979			ext4_std_error(sb, err);
1980	}
1981
1982errout:
1983	ret = ext4_journal_stop(handle);
1984	return err ? err : ret;
 
 
1985
1986invalid_resize_inode:
1987	ext4_error(sb, "corrupted/inconsistent resize inode");
1988	return -EINVAL;
1989}
1990
1991/*
1992 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1993 *
1994 * @sb: super block of the fs to be resized
1995 * @n_blocks_count: the number of blocks resides in the resized fs
1996 */
1997int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1998{
1999	struct ext4_new_flex_group_data *flex_gd = NULL;
2000	struct ext4_sb_info *sbi = EXT4_SB(sb);
2001	struct ext4_super_block *es = sbi->s_es;
2002	struct buffer_head *bh;
2003	struct inode *resize_inode = NULL;
2004	ext4_grpblk_t add, offset;
2005	unsigned long n_desc_blocks;
2006	unsigned long o_desc_blocks;
2007	ext4_group_t o_group;
2008	ext4_group_t n_group;
2009	ext4_fsblk_t o_blocks_count;
2010	ext4_fsblk_t n_blocks_count_retry = 0;
2011	unsigned long last_update_time = 0;
2012	int err = 0;
2013	int meta_bg;
2014	unsigned int flexbg_size = ext4_flex_bg_size(sbi);
2015
2016	/* See if the device is actually as big as what was requested */
2017	bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
2018	if (IS_ERR(bh)) {
2019		ext4_warning(sb, "can't read last block, resize aborted");
2020		return -ENOSPC;
2021	}
2022	brelse(bh);
2023
2024	/*
2025	 * For bigalloc, trim the requested size to the nearest cluster
2026	 * boundary to avoid creating an unusable filesystem. We do this
2027	 * silently, instead of returning an error, to avoid breaking
2028	 * callers that blindly resize the filesystem to the full size of
2029	 * the underlying block device.
2030	 */
2031	if (ext4_has_feature_bigalloc(sb))
2032		n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
2033
2034retry:
2035	o_blocks_count = ext4_blocks_count(es);
2036
2037	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
2038		 "to %llu blocks", o_blocks_count, n_blocks_count);
2039
2040	if (n_blocks_count < o_blocks_count) {
2041		/* On-line shrinking not supported */
2042		ext4_warning(sb, "can't shrink FS - resize aborted");
2043		return -EINVAL;
2044	}
2045
2046	if (n_blocks_count == o_blocks_count)
2047		/* Nothing need to do */
2048		return 0;
2049
2050	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
2051	if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2052		ext4_warning(sb, "resize would cause inodes_count overflow");
2053		return -EINVAL;
2054	}
2055	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2056
2057	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2058	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2059
2060	meta_bg = ext4_has_feature_meta_bg(sb);
2061
2062	if (ext4_has_feature_resize_inode(sb)) {
2063		if (meta_bg) {
2064			ext4_error(sb, "resize_inode and meta_bg enabled "
2065				   "simultaneously");
2066			return -EINVAL;
2067		}
2068		if (n_desc_blocks > o_desc_blocks +
2069		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
2070			n_blocks_count_retry = n_blocks_count;
2071			n_desc_blocks = o_desc_blocks +
2072				le16_to_cpu(es->s_reserved_gdt_blocks);
2073			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2074			n_blocks_count = (ext4_fsblk_t)n_group *
2075				EXT4_BLOCKS_PER_GROUP(sb) +
2076				le32_to_cpu(es->s_first_data_block);
2077			n_group--; /* set to last group number */
2078		}
2079
2080		if (!resize_inode)
2081			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2082						 EXT4_IGET_SPECIAL);
2083		if (IS_ERR(resize_inode)) {
2084			ext4_warning(sb, "Error opening resize inode");
2085			return PTR_ERR(resize_inode);
2086		}
2087	}
2088
2089	if ((!resize_inode && !meta_bg && n_desc_blocks > o_desc_blocks) || n_blocks_count == o_blocks_count) {
2090		err = ext4_convert_meta_bg(sb, resize_inode);
2091		if (err)
2092			goto out;
2093		if (resize_inode) {
2094			iput(resize_inode);
2095			resize_inode = NULL;
2096		}
2097		if (n_blocks_count_retry) {
2098			n_blocks_count = n_blocks_count_retry;
2099			n_blocks_count_retry = 0;
2100			goto retry;
2101		}
2102	}
2103
2104	/*
2105	 * Make sure the last group has enough space so that it's
2106	 * guaranteed to have enough space for all metadata blocks
2107	 * that it might need to hold.  (We might not need to store
2108	 * the inode table blocks in the last block group, but there
2109	 * will be cases where this might be needed.)
2110	 */
2111	if ((ext4_group_first_block_no(sb, n_group) +
2112	     ext4_group_overhead_blocks(sb, n_group) + 2 +
2113	     sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2114		n_blocks_count = ext4_group_first_block_no(sb, n_group);
2115		n_group--;
2116		n_blocks_count_retry = 0;
2117		if (resize_inode) {
2118			iput(resize_inode);
2119			resize_inode = NULL;
2120		}
2121		goto retry;
2122	}
2123
2124	/* extend the last group */
2125	if (n_group == o_group)
2126		add = n_blocks_count - o_blocks_count;
2127	else
2128		add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2129	if (add > 0) {
2130		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2131		if (err)
2132			goto out;
2133	}
2134
2135	if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2136		goto out;
2137
2138	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2139	if (err)
2140		goto out;
2141
2142	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2143	if (err)
2144		goto out;
2145
2146	flex_gd = alloc_flex_gd(flexbg_size, o_group, n_group);
2147	if (flex_gd == NULL) {
2148		err = -ENOMEM;
2149		goto out;
2150	}
2151
2152	/* Add flex groups. Note that a regular group is a
2153	 * flex group with 1 group.
2154	 */
2155	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count)) {
2156		if (time_is_before_jiffies(last_update_time + HZ * 10)) {
 
2157			if (last_update_time)
2158				ext4_msg(sb, KERN_INFO,
2159					 "resized to %llu blocks",
2160					 ext4_blocks_count(es));
2161			last_update_time = jiffies;
2162		}
2163		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2164			break;
2165		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2166		if (unlikely(err))
2167			break;
2168	}
2169
2170	if (!err && n_blocks_count_retry) {
2171		n_blocks_count = n_blocks_count_retry;
2172		n_blocks_count_retry = 0;
2173		free_flex_gd(flex_gd);
2174		flex_gd = NULL;
2175		if (resize_inode) {
2176			iput(resize_inode);
2177			resize_inode = NULL;
2178		}
2179		goto retry;
2180	}
2181
2182out:
2183	if (flex_gd)
2184		free_flex_gd(flex_gd);
2185	if (resize_inode != NULL)
2186		iput(resize_inode);
2187	if (err)
2188		ext4_warning(sb, "error (%d) occurred during "
2189			     "file system resize", err);
2190	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2191		 ext4_blocks_count(es));
2192	return err;
2193}