1/*
   2 *  linux/fs/ext4/resize.c
   3 *
   4 * Support for resizing an ext4 filesystem while it is mounted.
   5 *
   6 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   7 *
   8 * This could probably be made into a module, because it is not often in use.
   9 */
  10
  11
  12#define EXT4FS_DEBUG
  13
  14#include <linux/errno.h>
  15#include <linux/slab.h>
  16
  17#include "ext4_jbd2.h"
  18
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  19int ext4_resize_begin(struct super_block *sb)
  20{
 
  21	int ret = 0;
  22
  23	if (!capable(CAP_SYS_RESOURCE))
  24		return -EPERM;
  25
  26	/*
 
 
 
 
 
 
 
 
 
 
 
 
  27	 * We are not allowed to do online-resizing on a filesystem mounted
  28	 * with error, because it can destroy the filesystem easily.
  29	 */
  30	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  31		ext4_warning(sb, "There are errors in the filesystem, "
  32			     "so online resizing is not allowed\n");
  33		return -EPERM;
  34	}
  35
  36	if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
 
 
 
 
 
 
  37		ret = -EBUSY;
  38
  39	return ret;
  40}
  41
  42void ext4_resize_end(struct super_block *sb)
  43{
  44	clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
  45	smp_mb__after_clear_bit();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  46}
  47
  48#define outside(b, first, last)	((b) < (first) || (b) >= (last))
  49#define inside(b, first, last)	((b) >= (first) && (b) < (last))
  50
  51static int verify_group_input(struct super_block *sb,
  52			      struct ext4_new_group_data *input)
  53{
  54	struct ext4_sb_info *sbi = EXT4_SB(sb);
  55	struct ext4_super_block *es = sbi->s_es;
  56	ext4_fsblk_t start = ext4_blocks_count(es);
  57	ext4_fsblk_t end = start + input->blocks_count;
  58	ext4_group_t group = input->group;
  59	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  60	unsigned overhead = ext4_bg_has_super(sb, group) ?
  61		(1 + ext4_bg_num_gdb(sb, group) +
  62		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
  63	ext4_fsblk_t metaend = start + overhead;
  64	struct buffer_head *bh = NULL;
  65	ext4_grpblk_t free_blocks_count, offset;
  66	int err = -EINVAL;
  67
  68	input->free_blocks_count = free_blocks_count =
 
 
 
 
 
 
 
 
  69		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
  70
  71	if (test_opt(sb, DEBUG))
  72		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
  73		       "(%d free, %u reserved)\n",
  74		       ext4_bg_has_super(sb, input->group) ? "normal" :
  75		       "no-super", input->group, input->blocks_count,
  76		       free_blocks_count, input->reserved_blocks);
  77
  78	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
  79	if (group != sbi->s_groups_count)
  80		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
  81			     input->group, sbi->s_groups_count);
  82	else if (offset != 0)
  83			ext4_warning(sb, "Last group not full");
  84	else if (input->reserved_blocks > input->blocks_count / 5)
  85		ext4_warning(sb, "Reserved blocks too high (%u)",
  86			     input->reserved_blocks);
  87	else if (free_blocks_count < 0)
  88		ext4_warning(sb, "Bad blocks count %u",
  89			     input->blocks_count);
  90	else if (!(bh = sb_bread(sb, end - 1)))
 
 
  91		ext4_warning(sb, "Cannot read last block (%llu)",
  92			     end - 1);
  93	else if (outside(input->block_bitmap, start, end))
  94		ext4_warning(sb, "Block bitmap not in group (block %llu)",
  95			     (unsigned long long)input->block_bitmap);
  96	else if (outside(input->inode_bitmap, start, end))
  97		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
  98			     (unsigned long long)input->inode_bitmap);
  99	else if (outside(input->inode_table, start, end) ||
 100		 outside(itend - 1, start, end))
 101		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 102			     (unsigned long long)input->inode_table, itend - 1);
 103	else if (input->inode_bitmap == input->block_bitmap)
 104		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 105			     (unsigned long long)input->block_bitmap);
 106	else if (inside(input->block_bitmap, input->inode_table, itend))
 107		ext4_warning(sb, "Block bitmap (%llu) in inode table "
 108			     "(%llu-%llu)",
 109			     (unsigned long long)input->block_bitmap,
 110			     (unsigned long long)input->inode_table, itend - 1);
 111	else if (inside(input->inode_bitmap, input->inode_table, itend))
 112		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 113			     "(%llu-%llu)",
 114			     (unsigned long long)input->inode_bitmap,
 115			     (unsigned long long)input->inode_table, itend - 1);
 116	else if (inside(input->block_bitmap, start, metaend))
 117		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 118			     (unsigned long long)input->block_bitmap,
 119			     start, metaend - 1);
 120	else if (inside(input->inode_bitmap, start, metaend))
 121		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 122			     (unsigned long long)input->inode_bitmap,
 123			     start, metaend - 1);
 124	else if (inside(input->inode_table, start, metaend) ||
 125		 inside(itend - 1, start, metaend))
 126		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 127			     "(%llu-%llu)",
 128			     (unsigned long long)input->inode_table,
 129			     itend - 1, start, metaend - 1);
 130	else
 131		err = 0;
 132	brelse(bh);
 133
 134	return err;
 135}
 136
 137/*
 138 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 139 * group each time.
 140 */
 141struct ext4_new_flex_group_data {
 142	struct ext4_new_group_data *groups;	/* new_group_data for groups
 143						   in the flex group */
 144	__u16 *bg_flags;			/* block group flags of groups
 145						   in @groups */
 146	ext4_group_t count;			/* number of groups in @groups
 147						 */
 148};
 149
 150/*
 151 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 152 * @flexbg_size.
 153 *
 154 * Returns NULL on failure otherwise address of the allocated structure.
 155 */
 156static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 157{
 158	struct ext4_new_flex_group_data *flex_gd;
 159
 160	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 161	if (flex_gd == NULL)
 162		goto out3;
 163
 164	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
 165		goto out2;
 166	flex_gd->count = flexbg_size;
 167
 168	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 169				  flexbg_size, GFP_NOFS);
 
 170	if (flex_gd->groups == NULL)
 171		goto out2;
 172
 173	flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 
 174	if (flex_gd->bg_flags == NULL)
 175		goto out1;
 176
 177	return flex_gd;
 178
 179out1:
 180	kfree(flex_gd->groups);
 181out2:
 182	kfree(flex_gd);
 183out3:
 184	return NULL;
 185}
 186
 187static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 188{
 189	kfree(flex_gd->bg_flags);
 190	kfree(flex_gd->groups);
 191	kfree(flex_gd);
 192}
 193
 194/*
 195 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 196 * and inode tables for a flex group.
 197 *
 198 * This function is used by 64bit-resize.  Note that this function allocates
 199 * group tables from the 1st group of groups contained by @flexgd, which may
 200 * be a partial of a flex group.
 201 *
 202 * @sb: super block of fs to which the groups belongs
 
 
 
 203 */
 204static void ext4_alloc_group_tables(struct super_block *sb,
 205				struct ext4_new_flex_group_data *flex_gd,
 206				int flexbg_size)
 207{
 208	struct ext4_new_group_data *group_data = flex_gd->groups;
 209	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 210	ext4_fsblk_t start_blk;
 211	ext4_fsblk_t last_blk;
 212	ext4_group_t src_group;
 213	ext4_group_t bb_index = 0;
 214	ext4_group_t ib_index = 0;
 215	ext4_group_t it_index = 0;
 216	ext4_group_t group;
 217	ext4_group_t last_group;
 218	unsigned overhead;
 
 
 219
 220	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 221
 222	src_group = group_data[0].group;
 223	last_group  = src_group + flex_gd->count - 1;
 224
 225	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 226	       (last_group & ~(flexbg_size - 1))));
 227next_group:
 228	group = group_data[0].group;
 
 
 229	start_blk = ext4_group_first_block_no(sb, src_group);
 230	last_blk = start_blk + group_data[src_group - group].blocks_count;
 231
 232	overhead = ext4_bg_has_super(sb, src_group) ?
 233		   (1 + ext4_bg_num_gdb(sb, src_group) +
 234		    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
 235
 236	start_blk += overhead;
 237
 238	BUG_ON(src_group >= group_data[0].group + flex_gd->count);
 239	/* We collect contiguous blocks as much as possible. */
 240	src_group++;
 241	for (; src_group <= last_group; src_group++)
 242		if (!ext4_bg_has_super(sb, src_group))
 
 243			last_blk += group_data[src_group - group].blocks_count;
 244		else
 245			break;
 
 246
 247	/* Allocate block bitmaps */
 248	for (; bb_index < flex_gd->count; bb_index++) {
 249		if (start_blk >= last_blk)
 250			goto next_group;
 251		group_data[bb_index].block_bitmap = start_blk++;
 252		ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 253		group -= group_data[0].group;
 254		group_data[group].free_blocks_count--;
 255		if (flexbg_size > 1)
 256			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 257	}
 258
 259	/* Allocate inode bitmaps */
 260	for (; ib_index < flex_gd->count; ib_index++) {
 261		if (start_blk >= last_blk)
 262			goto next_group;
 263		group_data[ib_index].inode_bitmap = start_blk++;
 264		ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 265		group -= group_data[0].group;
 266		group_data[group].free_blocks_count--;
 267		if (flexbg_size > 1)
 268			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 269	}
 270
 271	/* Allocate inode tables */
 272	for (; it_index < flex_gd->count; it_index++) {
 273		if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
 
 
 
 274			goto next_group;
 275		group_data[it_index].inode_table = start_blk;
 276		ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
 
 277		group -= group_data[0].group;
 278		group_data[group].free_blocks_count -=
 279					EXT4_SB(sb)->s_itb_per_group;
 280		if (flexbg_size > 1)
 281			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 282
 
 
 
 
 
 
 
 
 
 283		start_blk += EXT4_SB(sb)->s_itb_per_group;
 284	}
 285
 
 
 
 
 
 
 
 286	if (test_opt(sb, DEBUG)) {
 287		int i;
 288		group = group_data[0].group;
 289
 290		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 291		       "%d groups, flexbg size is %d:\n", flex_gd->count,
 292		       flexbg_size);
 293
 294		for (i = 0; i < flex_gd->count; i++) {
 295			printk(KERN_DEBUG "adding %s group %u: %u "
 296			       "blocks (%d free)\n",
 297			       ext4_bg_has_super(sb, group + i) ? "normal" :
 298			       "no-super", group + i,
 299			       group_data[i].blocks_count,
 300			       group_data[i].free_blocks_count);
 
 301		}
 302	}
 
 303}
 304
 305static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 306				  ext4_fsblk_t blk)
 307{
 308	struct buffer_head *bh;
 309	int err;
 310
 311	bh = sb_getblk(sb, blk);
 312	if (!bh)
 313		return ERR_PTR(-EIO);
 
 314	if ((err = ext4_journal_get_write_access(handle, bh))) {
 315		brelse(bh);
 316		bh = ERR_PTR(err);
 317	} else {
 318		memset(bh->b_data, 0, sb->s_blocksize);
 319		set_buffer_uptodate(bh);
 320	}
 321
 322	return bh;
 323}
 324
 325/*
 326 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 327 * If that fails, restart the transaction & regain write access for the
 328 * buffer head which is used for block_bitmap modifications.
 329 */
 330static int extend_or_restart_transaction(handle_t *handle, int thresh)
 331{
 332	int err;
 333
 334	if (ext4_handle_has_enough_credits(handle, thresh))
 335		return 0;
 336
 337	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 338	if (err < 0)
 339		return err;
 340	if (err) {
 341		err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 342		if (err)
 343			return err;
 344	}
 345
 346	return 0;
 347}
 348
 349/*
 350 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 351 *
 352 * Helper function for ext4_setup_new_group_blocks() which set .
 353 *
 354 * @sb: super block
 355 * @handle: journal handle
 356 * @flex_gd: flex group data
 357 */
 358static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 359			struct ext4_new_flex_group_data *flex_gd,
 360			ext4_fsblk_t block, ext4_group_t count)
 361{
 
 
 362	ext4_group_t count2;
 363
 364	ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 365	for (count2 = count; count > 0; count -= count2, block += count2) {
 
 
 366		ext4_fsblk_t start;
 367		struct buffer_head *bh;
 368		ext4_group_t group;
 369		int err;
 370
 371		ext4_get_group_no_and_offset(sb, block, &group, NULL);
 372		start = ext4_group_first_block_no(sb, group);
 373		group -= flex_gd->groups[0].group;
 374
 375		count2 = sb->s_blocksize * 8 - (block - start);
 376		if (count2 > count)
 377			count2 = count;
 378
 379		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 380			BUG_ON(flex_gd->count > 1);
 381			continue;
 382		}
 383
 384		err = extend_or_restart_transaction(handle, 1);
 385		if (err)
 386			return err;
 387
 388		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 389		if (!bh)
 390			return -EIO;
 391
 
 392		err = ext4_journal_get_write_access(handle, bh);
 393		if (err)
 
 394			return err;
 395		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 396			   block - start, count2);
 397		ext4_set_bits(bh->b_data, block - start, count2);
 
 398
 399		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 400		if (unlikely(err))
 401			return err;
 402		brelse(bh);
 403	}
 404
 405	return 0;
 406}
 407
 408/*
 409 * Set up the block and inode bitmaps, and the inode table for the new groups.
 410 * This doesn't need to be part of the main transaction, since we are only
 411 * changing blocks outside the actual filesystem.  We still do journaling to
 412 * ensure the recovery is correct in case of a failure just after resize.
 413 * If any part of this fails, we simply abort the resize.
 414 *
 415 * setup_new_flex_group_blocks handles a flex group as follow:
 416 *  1. copy super block and GDT, and initialize group tables if necessary.
 417 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 418 *     super block and GDT.
 419 *  2. allocate group tables in block bitmaps, that is, set bits in block
 420 *     bitmap for blocks taken by group tables.
 421 */
 422static int setup_new_flex_group_blocks(struct super_block *sb,
 423				struct ext4_new_flex_group_data *flex_gd)
 424{
 425	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 426	ext4_fsblk_t start;
 427	ext4_fsblk_t block;
 428	struct ext4_sb_info *sbi = EXT4_SB(sb);
 429	struct ext4_super_block *es = sbi->s_es;
 430	struct ext4_new_group_data *group_data = flex_gd->groups;
 431	__u16 *bg_flags = flex_gd->bg_flags;
 432	handle_t *handle;
 433	ext4_group_t group, count;
 434	struct buffer_head *bh = NULL;
 435	int reserved_gdb, i, j, err = 0, err2;
 
 436
 437	BUG_ON(!flex_gd->count || !group_data ||
 438	       group_data[0].group != sbi->s_groups_count);
 439
 440	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 
 441
 442	/* This transaction may be extended/restarted along the way */
 443	handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 444	if (IS_ERR(handle))
 445		return PTR_ERR(handle);
 446
 447	group = group_data[0].group;
 448	for (i = 0; i < flex_gd->count; i++, group++) {
 449		unsigned long gdblocks;
 
 450
 451		gdblocks = ext4_bg_num_gdb(sb, group);
 452		start = ext4_group_first_block_no(sb, group);
 453
 
 
 
 
 
 
 
 
 
 
 
 
 454		/* Copy all of the GDT blocks into the backup in this group */
 455		for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
 456			struct buffer_head *gdb;
 457
 458			ext4_debug("update backup group %#04llx\n", block);
 459			err = extend_or_restart_transaction(handle, 1);
 460			if (err)
 461				goto out;
 462
 463			gdb = sb_getblk(sb, block);
 464			if (!gdb) {
 465				err = -EIO;
 466				goto out;
 467			}
 468
 
 469			err = ext4_journal_get_write_access(handle, gdb);
 470			if (err) {
 471				brelse(gdb);
 472				goto out;
 473			}
 474			memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 475			       gdb->b_size);
 476			set_buffer_uptodate(gdb);
 477
 478			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 479			if (unlikely(err)) {
 480				brelse(gdb);
 481				goto out;
 482			}
 483			brelse(gdb);
 484		}
 485
 486		/* Zero out all of the reserved backup group descriptor
 487		 * table blocks
 488		 */
 489		if (ext4_bg_has_super(sb, group)) {
 490			err = sb_issue_zeroout(sb, gdblocks + start + 1,
 491					reserved_gdb, GFP_NOFS);
 492			if (err)
 493				goto out;
 494		}
 495
 
 496		/* Initialize group tables of the grop @group */
 497		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 498			goto handle_bb;
 499
 500		/* Zero out all of the inode table blocks */
 501		block = group_data[i].inode_table;
 502		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 503			   block, sbi->s_itb_per_group);
 504		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 505				       GFP_NOFS);
 506		if (err)
 507			goto out;
 508
 509handle_bb:
 510		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 511			goto handle_ib;
 512
 513		/* Initialize block bitmap of the @group */
 514		block = group_data[i].block_bitmap;
 515		err = extend_or_restart_transaction(handle, 1);
 516		if (err)
 517			goto out;
 518
 519		bh = bclean(handle, sb, block);
 520		if (IS_ERR(bh)) {
 521			err = PTR_ERR(bh);
 522			goto out;
 523		}
 524		if (ext4_bg_has_super(sb, group)) {
 
 525			ext4_debug("mark backup superblock %#04llx (+0)\n",
 526				   start);
 527			ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
 528						     1);
 529		}
 530		ext4_mark_bitmap_end(group_data[i].blocks_count,
 531				     sb->s_blocksize * 8, bh->b_data);
 532		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 533		if (err)
 534			goto out;
 535		brelse(bh);
 536
 537handle_ib:
 538		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 539			continue;
 540
 541		/* Initialize inode bitmap of the @group */
 542		block = group_data[i].inode_bitmap;
 543		err = extend_or_restart_transaction(handle, 1);
 544		if (err)
 545			goto out;
 546		/* Mark unused entries in inode bitmap used */
 547		bh = bclean(handle, sb, block);
 548		if (IS_ERR(bh)) {
 549			err = PTR_ERR(bh);
 550			goto out;
 551		}
 552
 553		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 554				     sb->s_blocksize * 8, bh->b_data);
 555		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 556		if (err)
 557			goto out;
 558		brelse(bh);
 559	}
 560	bh = NULL;
 561
 562	/* Mark group tables in block bitmap */
 563	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 564		count = group_table_count[j];
 565		start = (&group_data[0].block_bitmap)[j];
 566		block = start;
 567		for (i = 1; i < flex_gd->count; i++) {
 568			block += group_table_count[j];
 569			if (block == (&group_data[i].block_bitmap)[j]) {
 570				count += group_table_count[j];
 571				continue;
 572			}
 573			err = set_flexbg_block_bitmap(sb, handle,
 574						flex_gd, start, count);
 
 
 
 
 575			if (err)
 576				goto out;
 577			count = group_table_count[j];
 578			start = group_data[i].block_bitmap;
 579			block = start;
 580		}
 581
 582		if (count) {
 583			err = set_flexbg_block_bitmap(sb, handle,
 584						flex_gd, start, count);
 
 
 
 
 585			if (err)
 586				goto out;
 587		}
 588	}
 589
 590out:
 591	brelse(bh);
 592	err2 = ext4_journal_stop(handle);
 593	if (err2 && !err)
 594		err = err2;
 595
 596	return err;
 597}
 598
 599/*
 600 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 601 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 602 * calling this for the first time.  In a sparse filesystem it will be the
 603 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 604 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 605 */
 606static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 607				  unsigned *five, unsigned *seven)
 608{
 609	unsigned *min = three;
 610	int mult = 3;
 611	unsigned ret;
 612
 613	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 614					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 615		ret = *min;
 616		*min += 1;
 617		return ret;
 618	}
 619
 620	if (*five < *min) {
 621		min = five;
 622		mult = 5;
 623	}
 624	if (*seven < *min) {
 625		min = seven;
 626		mult = 7;
 627	}
 628
 629	ret = *min;
 630	*min *= mult;
 631
 632	return ret;
 633}
 634
 635/*
 636 * Check that all of the backup GDT blocks are held in the primary GDT block.
 637 * It is assumed that they are stored in group order.  Returns the number of
 638 * groups in current filesystem that have BACKUPS, or -ve error code.
 639 */
 640static int verify_reserved_gdb(struct super_block *sb,
 641			       ext4_group_t end,
 642			       struct buffer_head *primary)
 643{
 644	const ext4_fsblk_t blk = primary->b_blocknr;
 645	unsigned three = 1;
 646	unsigned five = 5;
 647	unsigned seven = 7;
 648	unsigned grp;
 649	__le32 *p = (__le32 *)primary->b_data;
 650	int gdbackups = 0;
 651
 652	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 653		if (le32_to_cpu(*p++) !=
 654		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 655			ext4_warning(sb, "reserved GDT %llu"
 656				     " missing grp %d (%llu)",
 657				     blk, grp,
 658				     grp *
 659				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 660				     blk);
 661			return -EINVAL;
 662		}
 663		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 664			return -EFBIG;
 665	}
 666
 667	return gdbackups;
 668}
 669
 670/*
 671 * Called when we need to bring a reserved group descriptor table block into
 672 * use from the resize inode.  The primary copy of the new GDT block currently
 673 * is an indirect block (under the double indirect block in the resize inode).
 674 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 675 * block, in group order.  Even though we know all the block numbers we need,
 676 * we check to ensure that the resize inode has actually reserved these blocks.
 677 *
 678 * Don't need to update the block bitmaps because the blocks are still in use.
 679 *
 680 * We get all of the error cases out of the way, so that we are sure to not
 681 * fail once we start modifying the data on disk, because JBD has no rollback.
 682 */
 683static int add_new_gdb(handle_t *handle, struct inode *inode,
 684		       ext4_group_t group)
 685{
 686	struct super_block *sb = inode->i_sb;
 687	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 688	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 689	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 690	struct buffer_head **o_group_desc, **n_group_desc;
 691	struct buffer_head *dind;
 692	struct buffer_head *gdb_bh;
 693	int gdbackups;
 694	struct ext4_iloc iloc;
 695	__le32 *data;
 696	int err;
 697
 698	if (test_opt(sb, DEBUG))
 699		printk(KERN_DEBUG
 700		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 701		       gdb_num);
 702
 703	/*
 704	 * If we are not using the primary superblock/GDT copy don't resize,
 705         * because the user tools have no way of handling this.  Probably a
 706         * bad time to do it anyways.
 707         */
 708	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 709	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 710		ext4_warning(sb, "won't resize using backup superblock at %llu",
 711			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 712		return -EPERM;
 713	}
 714
 715	gdb_bh = sb_bread(sb, gdblock);
 716	if (!gdb_bh)
 717		return -EIO;
 718
 719	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 720	if (gdbackups < 0) {
 721		err = gdbackups;
 722		goto exit_bh;
 723	}
 724
 725	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 726	dind = sb_bread(sb, le32_to_cpu(*data));
 727	if (!dind) {
 728		err = -EIO;
 729		goto exit_bh;
 
 730	}
 731
 732	data = (__le32 *)dind->b_data;
 733	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 734		ext4_warning(sb, "new group %u GDT block %llu not reserved",
 735			     group, gdblock);
 736		err = -EINVAL;
 737		goto exit_dind;
 738	}
 739
 
 740	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 741	if (unlikely(err))
 742		goto exit_dind;
 743
 
 744	err = ext4_journal_get_write_access(handle, gdb_bh);
 745	if (unlikely(err))
 746		goto exit_sbh;
 747
 
 748	err = ext4_journal_get_write_access(handle, dind);
 749	if (unlikely(err))
 750		ext4_std_error(sb, err);
 
 
 751
 752	/* ext4_reserve_inode_write() gets a reference on the iloc */
 753	err = ext4_reserve_inode_write(handle, inode, &iloc);
 754	if (unlikely(err))
 755		goto exit_dindj;
 756
 757	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 758				     sizeof(struct buffer_head *),
 759				     GFP_NOFS);
 760	if (!n_group_desc) {
 761		err = -ENOMEM;
 762		ext4_warning(sb, "not enough memory for %lu groups",
 763			     gdb_num + 1);
 764		goto exit_inode;
 765	}
 766
 767	/*
 768	 * Finally, we have all of the possible failures behind us...
 769	 *
 770	 * Remove new GDT block from inode double-indirect block and clear out
 771	 * the new GDT block for use (which also "frees" the backup GDT blocks
 772	 * from the reserved inode).  We don't need to change the bitmaps for
 773	 * these blocks, because they are marked as in-use from being in the
 774	 * reserved inode, and will become GDT blocks (primary and backup).
 775	 */
 776	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 777	err = ext4_handle_dirty_metadata(handle, NULL, dind);
 778	if (unlikely(err)) {
 779		ext4_std_error(sb, err);
 780		goto exit_inode;
 781	}
 782	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 
 783	ext4_mark_iloc_dirty(handle, inode, &iloc);
 784	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 785	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 786	if (unlikely(err)) {
 787		ext4_std_error(sb, err);
 788		goto exit_inode;
 
 789	}
 790	brelse(dind);
 791
 792	o_group_desc = EXT4_SB(sb)->s_group_desc;
 
 793	memcpy(n_group_desc, o_group_desc,
 794	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 
 795	n_group_desc[gdb_num] = gdb_bh;
 796	EXT4_SB(sb)->s_group_desc = n_group_desc;
 797	EXT4_SB(sb)->s_gdb_count++;
 798	ext4_kvfree(o_group_desc);
 799
 
 800	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 801	err = ext4_handle_dirty_super_now(handle, sb);
 
 
 802	if (err)
 803		ext4_std_error(sb, err);
 804
 805	return err;
 806
 807exit_inode:
 808	ext4_kvfree(n_group_desc);
 809	/* ext4_handle_release_buffer(handle, iloc.bh); */
 810	brelse(iloc.bh);
 811exit_dindj:
 812	/* ext4_handle_release_buffer(handle, dind); */
 813exit_sbh:
 814	/* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
 815exit_dind:
 816	brelse(dind);
 817exit_bh:
 818	brelse(gdb_bh);
 819
 820	ext4_debug("leaving with error %d\n", err);
 821	return err;
 822}
 823
 824/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 825 * Called when we are adding a new group which has a backup copy of each of
 826 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 827 * We need to add these reserved backup GDT blocks to the resize inode, so
 828 * that they are kept for future resizing and not allocated to files.
 829 *
 830 * Each reserved backup GDT block will go into a different indirect block.
 831 * The indirect blocks are actually the primary reserved GDT blocks,
 832 * so we know in advance what their block numbers are.  We only get the
 833 * double-indirect block to verify it is pointing to the primary reserved
 834 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 835 * backup GDT blocks are stored in their reserved primary GDT block.
 836 */
 837static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 838			      ext4_group_t group)
 839{
 840	struct super_block *sb = inode->i_sb;
 841	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 
 842	struct buffer_head **primary;
 843	struct buffer_head *dind;
 844	struct ext4_iloc iloc;
 845	ext4_fsblk_t blk;
 846	__le32 *data, *end;
 847	int gdbackups = 0;
 848	int res, i;
 849	int err;
 850
 851	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 852	if (!primary)
 853		return -ENOMEM;
 854
 855	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 856	dind = sb_bread(sb, le32_to_cpu(*data));
 857	if (!dind) {
 858		err = -EIO;
 
 859		goto exit_free;
 860	}
 861
 862	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 863	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 864					 EXT4_ADDR_PER_BLOCK(sb));
 865	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 866
 867	/* Get each reserved primary GDT block and verify it holds backups */
 868	for (res = 0; res < reserved_gdb; res++, blk++) {
 869		if (le32_to_cpu(*data) != blk) {
 870			ext4_warning(sb, "reserved block %llu"
 871				     " not at offset %ld",
 872				     blk,
 873				     (long)(data - (__le32 *)dind->b_data));
 874			err = -EINVAL;
 875			goto exit_bh;
 876		}
 877		primary[res] = sb_bread(sb, blk);
 878		if (!primary[res]) {
 879			err = -EIO;
 
 880			goto exit_bh;
 881		}
 882		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 883		if (gdbackups < 0) {
 884			brelse(primary[res]);
 885			err = gdbackups;
 886			goto exit_bh;
 887		}
 888		if (++data >= end)
 889			data = (__le32 *)dind->b_data;
 890	}
 891
 892	for (i = 0; i < reserved_gdb; i++) {
 893		if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
 894			/*
 895			int j;
 896			for (j = 0; j < i; j++)
 897				ext4_handle_release_buffer(handle, primary[j]);
 898			 */
 899			goto exit_bh;
 900		}
 901	}
 902
 903	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 904		goto exit_bh;
 905
 906	/*
 907	 * Finally we can add each of the reserved backup GDT blocks from
 908	 * the new group to its reserved primary GDT block.
 909	 */
 910	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
 911	for (i = 0; i < reserved_gdb; i++) {
 912		int err2;
 913		data = (__le32 *)primary[i]->b_data;
 914		/* printk("reserving backup %lu[%u] = %lu\n",
 915		       primary[i]->b_blocknr, gdbackups,
 916		       blk + primary[i]->b_blocknr); */
 917		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 918		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
 919		if (!err)
 920			err = err2;
 921	}
 922	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
 
 923	ext4_mark_iloc_dirty(handle, inode, &iloc);
 924
 925exit_bh:
 926	while (--res >= 0)
 927		brelse(primary[res]);
 928	brelse(dind);
 929
 930exit_free:
 931	kfree(primary);
 932
 933	return err;
 934}
 935
 936/*
 937 * Update the backup copies of the ext4 metadata.  These don't need to be part
 938 * of the main resize transaction, because e2fsck will re-write them if there
 939 * is a problem (basically only OOM will cause a problem).  However, we
 940 * _should_ update the backups if possible, in case the primary gets trashed
 941 * for some reason and we need to run e2fsck from a backup superblock.  The
 942 * important part is that the new block and inode counts are in the backup
 943 * superblocks, and the location of the new group metadata in the GDT backups.
 944 *
 945 * We do not need take the s_resize_lock for this, because these
 946 * blocks are not otherwise touched by the filesystem code when it is
 947 * mounted.  We don't need to worry about last changing from
 948 * sbi->s_groups_count, because the worst that can happen is that we
 949 * do not copy the full number of backups at this time.  The resize
 950 * which changed s_groups_count will backup again.
 951 */
 952static void update_backups(struct super_block *sb,
 953			   int blk_off, char *data, int size)
 954{
 955	struct ext4_sb_info *sbi = EXT4_SB(sb);
 956	const ext4_group_t last = sbi->s_groups_count;
 957	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
 958	unsigned three = 1;
 959	unsigned five = 5;
 960	unsigned seven = 7;
 961	ext4_group_t group;
 962	int rest = sb->s_blocksize - size;
 963	handle_t *handle;
 964	int err = 0, err2;
 965
 966	handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 967	if (IS_ERR(handle)) {
 968		group = 1;
 969		err = PTR_ERR(handle);
 970		goto exit_err;
 971	}
 972
 973	ext4_superblock_csum_set(sb, (struct ext4_super_block *)data);
 
 
 
 
 
 
 974
 975	while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
 976		struct buffer_head *bh;
 
 977
 978		/* Out of journal space, and can't get more - abort - so sad */
 979		if (ext4_handle_valid(handle) &&
 980		    handle->h_buffer_credits == 0 &&
 981		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
 982		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
 983			break;
 984
 985		bh = sb_getblk(sb, group * bpg + blk_off);
 986		if (!bh) {
 987			err = -EIO;
 
 
 
 
 
 
 988			break;
 989		}
 990		ext4_debug("update metadata backup %#04lx\n",
 991			  (unsigned long)bh->b_blocknr);
 992		if ((err = ext4_journal_get_write_access(handle, bh)))
 
 
 
 993			break;
 
 994		lock_buffer(bh);
 995		memcpy(bh->b_data, data, size);
 996		if (rest)
 997			memset(bh->b_data + size, 0, rest);
 998		set_buffer_uptodate(bh);
 999		unlock_buffer(bh);
1000		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1001		if (unlikely(err))
1002			ext4_std_error(sb, err);
1003		brelse(bh);
 
 
 
 
 
 
 
1004	}
1005	if ((err2 = ext4_journal_stop(handle)) && !err)
1006		err = err2;
1007
1008	/*
1009	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1010	 * late to revert the resize, we shouldn't fail just because of
1011	 * the backup copies (they are only needed in case of corruption).
1012	 *
1013	 * However, if we got here we have a journal problem too, so we
1014	 * can't really start a transaction to mark the superblock.
1015	 * Chicken out and just set the flag on the hope it will be written
1016	 * to disk, and if not - we will simply wait until next fsck.
1017	 */
1018exit_err:
1019	if (err) {
1020		ext4_warning(sb, "can't update backup for group %u (err %d), "
1021			     "forcing fsck on next reboot", group, err);
1022		sbi->s_mount_state &= ~EXT4_VALID_FS;
1023		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1024		mark_buffer_dirty(sbi->s_sbh);
1025	}
1026}
1027
1028/*
1029 * ext4_add_new_descs() adds @count group descriptor of groups
1030 * starting at @group
1031 *
1032 * @handle: journal handle
1033 * @sb: super block
1034 * @group: the group no. of the first group desc to be added
1035 * @resize_inode: the resize inode
1036 * @count: number of group descriptors to be added
1037 */
1038static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1039			      ext4_group_t group, struct inode *resize_inode,
1040			      ext4_group_t count)
1041{
1042	struct ext4_sb_info *sbi = EXT4_SB(sb);
1043	struct ext4_super_block *es = sbi->s_es;
1044	struct buffer_head *gdb_bh;
1045	int i, gdb_off, gdb_num, err = 0;
 
1046
 
1047	for (i = 0; i < count; i++, group++) {
1048		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1049			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1050
1051		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1052		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1053
1054		/*
1055		 * We will only either add reserved group blocks to a backup group
1056		 * or remove reserved blocks for the first group in a new group block.
1057		 * Doing both would be mean more complex code, and sane people don't
1058		 * use non-sparse filesystems anymore.  This is already checked above.
1059		 */
1060		if (gdb_off) {
1061			gdb_bh = sbi->s_group_desc[gdb_num];
 
 
1062			err = ext4_journal_get_write_access(handle, gdb_bh);
1063
1064			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1065				err = reserve_backup_gdb(handle, resize_inode, group);
1066		} else
 
 
1067			err = add_new_gdb(handle, resize_inode, group);
 
1068		if (err)
1069			break;
1070	}
1071	return err;
1072}
1073
1074static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1075{
1076	struct buffer_head *bh = sb_getblk(sb, block);
1077	if (!bh)
1078		return NULL;
1079
1080	if (bitmap_uptodate(bh))
1081		return bh;
1082
1083	lock_buffer(bh);
1084	if (bh_submit_read(bh) < 0) {
1085		unlock_buffer(bh);
1086		brelse(bh);
1087		return NULL;
 
 
 
 
 
1088	}
1089	unlock_buffer(bh);
1090
1091	return bh;
1092}
1093
1094static int ext4_set_bitmap_checksums(struct super_block *sb,
1095				     ext4_group_t group,
1096				     struct ext4_group_desc *gdp,
1097				     struct ext4_new_group_data *group_data)
1098{
1099	struct buffer_head *bh;
1100
1101	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1102					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1103		return 0;
1104
1105	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1106	if (!bh)
1107		return -EIO;
1108	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1109				   EXT4_INODES_PER_GROUP(sb) / 8);
1110	brelse(bh);
1111
1112	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1113	if (!bh)
1114		return -EIO;
1115	ext4_block_bitmap_csum_set(sb, group, gdp, bh,
1116				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
1117	brelse(bh);
1118
1119	return 0;
1120}
1121
1122/*
1123 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1124 */
1125static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1126				struct ext4_new_flex_group_data *flex_gd)
1127{
1128	struct ext4_new_group_data	*group_data = flex_gd->groups;
1129	struct ext4_group_desc		*gdp;
1130	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1131	struct buffer_head		*gdb_bh;
1132	ext4_group_t			group;
1133	__u16				*bg_flags = flex_gd->bg_flags;
1134	int				i, gdb_off, gdb_num, err = 0;
1135	
1136
1137	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1138		group = group_data->group;
1139
1140		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1141		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1142
1143		/*
1144		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1145		 */
1146		gdb_bh = sbi->s_group_desc[gdb_num];
1147		/* Update group descriptor block for new group */
1148		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1149						 gdb_off * EXT4_DESC_SIZE(sb));
1150
1151		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1152		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1153		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1154		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1155		if (err) {
1156			ext4_std_error(sb, err);
1157			break;
1158		}
1159
1160		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1161		ext4_free_group_clusters_set(sb, gdp,
1162					     EXT4_B2C(sbi, group_data->free_blocks_count));
1163		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
 
 
 
1164		gdp->bg_flags = cpu_to_le16(*bg_flags);
1165		ext4_group_desc_csum_set(sb, group, gdp);
1166
1167		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1168		if (unlikely(err)) {
1169			ext4_std_error(sb, err);
1170			break;
1171		}
1172
1173		/*
1174		 * We can allocate memory for mb_alloc based on the new group
1175		 * descriptor
1176		 */
1177		err = ext4_mb_add_groupinfo(sb, group, gdp);
1178		if (err)
1179			break;
1180	}
1181	return err;
1182}
1183
1184/*
1185 * ext4_update_super() updates the super block so that the newly added
1186 * groups can be seen by the filesystem.
1187 *
1188 * @sb: super block
1189 * @flex_gd: new added groups
1190 */
1191static void ext4_update_super(struct super_block *sb,
1192			     struct ext4_new_flex_group_data *flex_gd)
1193{
1194	ext4_fsblk_t blocks_count = 0;
1195	ext4_fsblk_t free_blocks = 0;
1196	ext4_fsblk_t reserved_blocks = 0;
1197	struct ext4_new_group_data *group_data = flex_gd->groups;
1198	struct ext4_sb_info *sbi = EXT4_SB(sb);
1199	struct ext4_super_block *es = sbi->s_es;
1200	int i, ret;
1201
1202	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1203	/*
1204	 * Make the new blocks and inodes valid next.  We do this before
1205	 * increasing the group count so that once the group is enabled,
1206	 * all of its blocks and inodes are already valid.
1207	 *
1208	 * We always allocate group-by-group, then block-by-block or
1209	 * inode-by-inode within a group, so enabling these
1210	 * blocks/inodes before the group is live won't actually let us
1211	 * allocate the new space yet.
1212	 */
1213	for (i = 0; i < flex_gd->count; i++) {
1214		blocks_count += group_data[i].blocks_count;
1215		free_blocks += group_data[i].free_blocks_count;
1216	}
1217
1218	reserved_blocks = ext4_r_blocks_count(es) * 100;
1219	do_div(reserved_blocks, ext4_blocks_count(es));
1220	reserved_blocks *= blocks_count;
1221	do_div(reserved_blocks, 100);
1222
 
1223	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1224	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1225	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1226		     flex_gd->count);
1227	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1228		     flex_gd->count);
1229
 
1230	/*
1231	 * We need to protect s_groups_count against other CPUs seeing
1232	 * inconsistent state in the superblock.
1233	 *
1234	 * The precise rules we use are:
1235	 *
1236	 * * Writers must perform a smp_wmb() after updating all
1237	 *   dependent data and before modifying the groups count
1238	 *
1239	 * * Readers must perform an smp_rmb() after reading the groups
1240	 *   count and before reading any dependent data.
1241	 *
1242	 * NB. These rules can be relaxed when checking the group count
1243	 * while freeing data, as we can only allocate from a block
1244	 * group after serialising against the group count, and we can
1245	 * only then free after serialising in turn against that
1246	 * allocation.
1247	 */
1248	smp_wmb();
1249
1250	/* Update the global fs size fields */
1251	sbi->s_groups_count += flex_gd->count;
 
 
1252
1253	/* Update the reserved block counts only once the new group is
1254	 * active. */
1255	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1256				reserved_blocks);
 
 
1257
1258	/* Update the free space counts */
1259	percpu_counter_add(&sbi->s_freeclusters_counter,
1260			   EXT4_B2C(sbi, free_blocks));
1261	percpu_counter_add(&sbi->s_freeinodes_counter,
1262			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1263
1264	if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1265				      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1266	    sbi->s_log_groups_per_flex) {
1267		ext4_group_t flex_group;
 
 
1268		flex_group = ext4_flex_group(sbi, group_data[0].group);
1269		atomic_add(EXT4_B2C(sbi, free_blocks),
1270			   &sbi->s_flex_groups[flex_group].free_clusters);
 
1271		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1272			   &sbi->s_flex_groups[flex_group].free_inodes);
1273	}
1274
1275	/*
1276	 * Update the fs overhead information
1277	 */
1278	ext4_calculate_overhead(sb);
1279
1280	if (test_opt(sb, DEBUG))
1281		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1282		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1283		       blocks_count, free_blocks, reserved_blocks);
1284}
1285
1286/* Add a flex group to an fs. Ensure we handle all possible error conditions
1287 * _before_ we start modifying the filesystem, because we cannot abort the
1288 * transaction and not have it write the data to disk.
1289 */
1290static int ext4_flex_group_add(struct super_block *sb,
1291			       struct inode *resize_inode,
1292			       struct ext4_new_flex_group_data *flex_gd)
1293{
1294	struct ext4_sb_info *sbi = EXT4_SB(sb);
1295	struct ext4_super_block *es = sbi->s_es;
1296	ext4_fsblk_t o_blocks_count;
1297	ext4_grpblk_t last;
1298	ext4_group_t group;
1299	handle_t *handle;
1300	unsigned reserved_gdb;
1301	int err = 0, err2 = 0, credit;
1302
1303	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1304
1305	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1306	o_blocks_count = ext4_blocks_count(es);
1307	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1308	BUG_ON(last);
1309
1310	err = setup_new_flex_group_blocks(sb, flex_gd);
1311	if (err)
1312		goto exit;
1313	/*
1314	 * We will always be modifying at least the superblock and  GDT
1315	 * block.  If we are adding a group past the last current GDT block,
1316	 * we will also modify the inode and the dindirect block.  If we
1317	 * are adding a group with superblock/GDT backups  we will also
1318	 * modify each of the reserved GDT dindirect blocks.
1319	 */
1320	credit = flex_gd->count * 4 + reserved_gdb;
1321	handle = ext4_journal_start_sb(sb, credit);
 
 
 
1322	if (IS_ERR(handle)) {
1323		err = PTR_ERR(handle);
1324		goto exit;
1325	}
1326
 
1327	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1328	if (err)
1329		goto exit_journal;
1330
1331	group = flex_gd->groups[0].group;
1332	BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1333	err = ext4_add_new_descs(handle, sb, group,
1334				resize_inode, flex_gd->count);
1335	if (err)
1336		goto exit_journal;
1337
1338	err = ext4_setup_new_descs(handle, sb, flex_gd);
1339	if (err)
1340		goto exit_journal;
1341
1342	ext4_update_super(sb, flex_gd);
1343
1344	err = ext4_handle_dirty_super(handle, sb);
1345
1346exit_journal:
1347	err2 = ext4_journal_stop(handle);
1348	if (!err)
1349		err = err2;
1350
1351	if (!err) {
1352		int i;
 
 
 
 
 
1353		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1354			       sizeof(struct ext4_super_block));
1355		for (i = 0; i < flex_gd->count; i++, group++) {
1356			struct buffer_head *gdb_bh;
1357			int gdb_num;
1358			gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
1359			gdb_bh = sbi->s_group_desc[gdb_num];
 
 
1360			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1361				       gdb_bh->b_size);
 
1362		}
1363	}
1364exit:
1365	return err;
1366}
1367
1368static int ext4_setup_next_flex_gd(struct super_block *sb,
1369				    struct ext4_new_flex_group_data *flex_gd,
1370				    ext4_fsblk_t n_blocks_count,
1371				    unsigned long flexbg_size)
1372{
1373	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 
1374	struct ext4_new_group_data *group_data = flex_gd->groups;
1375	ext4_fsblk_t o_blocks_count;
1376	ext4_group_t n_group;
1377	ext4_group_t group;
1378	ext4_group_t last_group;
1379	ext4_grpblk_t last;
1380	ext4_grpblk_t blocks_per_group;
1381	unsigned long i;
1382
1383	blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1384
1385	o_blocks_count = ext4_blocks_count(es);
1386
1387	if (o_blocks_count == n_blocks_count)
1388		return 0;
1389
1390	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1391	BUG_ON(last);
1392	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1393
1394	last_group = group | (flexbg_size - 1);
1395	if (last_group > n_group)
1396		last_group = n_group;
1397
1398	flex_gd->count = last_group - group + 1;
1399
1400	for (i = 0; i < flex_gd->count; i++) {
1401		int overhead;
1402
1403		group_data[i].group = group + i;
1404		group_data[i].blocks_count = blocks_per_group;
1405		overhead = ext4_bg_has_super(sb, group + i) ?
1406			   (1 + ext4_bg_num_gdb(sb, group + i) +
1407			    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
1408		group_data[i].free_blocks_count = blocks_per_group - overhead;
1409		if (ext4_has_group_desc_csum(sb))
1410			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1411					       EXT4_BG_INODE_UNINIT;
1412		else
 
 
1413			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1414	}
1415
1416	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1417		/* We need to initialize block bitmap of last group. */
1418		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1419
1420	if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1421		group_data[i - 1].blocks_count = last + 1;
1422		group_data[i - 1].free_blocks_count -= blocks_per_group-
1423					last - 1;
1424	}
1425
1426	return 1;
1427}
1428
1429/* Add group descriptor data to an existing or new group descriptor block.
1430 * Ensure we handle all possible error conditions _before_ we start modifying
1431 * the filesystem, because we cannot abort the transaction and not have it
1432 * write the data to disk.
1433 *
1434 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1435 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1436 *
1437 * We only need to hold the superblock lock while we are actually adding
1438 * in the new group's counts to the superblock.  Prior to that we have
1439 * not really "added" the group at all.  We re-check that we are still
1440 * adding in the last group in case things have changed since verifying.
1441 */
1442int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1443{
1444	struct ext4_new_flex_group_data flex_gd;
1445	struct ext4_sb_info *sbi = EXT4_SB(sb);
1446	struct ext4_super_block *es = sbi->s_es;
1447	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1448		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1449	struct inode *inode = NULL;
1450	int gdb_off, gdb_num;
1451	int err;
1452	__u16 bg_flags = 0;
1453
1454	gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1455	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1456
1457	if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1458					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1459		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1460		return -EPERM;
1461	}
1462
1463	if (ext4_blocks_count(es) + input->blocks_count <
1464	    ext4_blocks_count(es)) {
1465		ext4_warning(sb, "blocks_count overflow");
1466		return -EINVAL;
1467	}
1468
1469	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1470	    le32_to_cpu(es->s_inodes_count)) {
1471		ext4_warning(sb, "inodes_count overflow");
1472		return -EINVAL;
1473	}
1474
1475	if (reserved_gdb || gdb_off == 0) {
1476		if (!EXT4_HAS_COMPAT_FEATURE(sb,
1477					     EXT4_FEATURE_COMPAT_RESIZE_INODE)
1478		    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1479			ext4_warning(sb,
1480				     "No reserved GDT blocks, can't resize");
1481			return -EPERM;
1482		}
1483		inode = ext4_iget(sb, EXT4_RESIZE_INO);
1484		if (IS_ERR(inode)) {
1485			ext4_warning(sb, "Error opening resize inode");
1486			return PTR_ERR(inode);
1487		}
1488	}
1489
1490
1491	err = verify_group_input(sb, input);
1492	if (err)
1493		goto out;
1494
 
 
 
 
 
 
 
 
1495	flex_gd.count = 1;
1496	flex_gd.groups = input;
1497	flex_gd.bg_flags = &bg_flags;
1498	err = ext4_flex_group_add(sb, inode, &flex_gd);
1499out:
1500	iput(inode);
1501	return err;
1502} /* ext4_group_add */
1503
1504/*
1505 * extend a group without checking assuming that checking has been done.
1506 */
1507static int ext4_group_extend_no_check(struct super_block *sb,
1508				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1509{
1510	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1511	handle_t *handle;
1512	int err = 0, err2;
1513
1514	/* We will update the superblock, one block bitmap, and
1515	 * one group descriptor via ext4_group_add_blocks().
1516	 */
1517	handle = ext4_journal_start_sb(sb, 3);
1518	if (IS_ERR(handle)) {
1519		err = PTR_ERR(handle);
1520		ext4_warning(sb, "error %d on journal start", err);
1521		return err;
1522	}
1523
 
1524	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1525	if (err) {
1526		ext4_warning(sb, "error %d on journal write access", err);
1527		goto errout;
1528	}
1529
 
1530	ext4_blocks_count_set(es, o_blocks_count + add);
1531	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
 
 
1532	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1533		   o_blocks_count + add);
1534	/* We add the blocks to the bitmap and set the group need init bit */
1535	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1536	if (err)
1537		goto errout;
1538	ext4_handle_dirty_super(handle, sb);
1539	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1540		   o_blocks_count + add);
1541errout:
1542	err2 = ext4_journal_stop(handle);
1543	if (err2 && !err)
1544		err = err2;
1545
1546	if (!err) {
1547		if (test_opt(sb, DEBUG))
1548			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1549			       "blocks\n", ext4_blocks_count(es));
1550		update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1551			       sizeof(struct ext4_super_block));
1552	}
1553	return err;
1554}
1555
1556/*
1557 * Extend the filesystem to the new number of blocks specified.  This entry
1558 * point is only used to extend the current filesystem to the end of the last
1559 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1560 * for emergencies (because it has no dependencies on reserved blocks).
1561 *
1562 * If we _really_ wanted, we could use default values to call ext4_group_add()
1563 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1564 * GDT blocks are reserved to grow to the desired size.
1565 */
1566int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1567		      ext4_fsblk_t n_blocks_count)
1568{
1569	ext4_fsblk_t o_blocks_count;
1570	ext4_grpblk_t last;
1571	ext4_grpblk_t add;
1572	struct buffer_head *bh;
1573	int err;
1574	ext4_group_t group;
1575
1576	o_blocks_count = ext4_blocks_count(es);
1577
1578	if (test_opt(sb, DEBUG))
1579		ext4_msg(sb, KERN_DEBUG,
1580			 "extending last group from %llu to %llu blocks",
1581			 o_blocks_count, n_blocks_count);
1582
1583	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1584		return 0;
1585
1586	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1587		ext4_msg(sb, KERN_ERR,
1588			 "filesystem too large to resize to %llu blocks safely",
1589			 n_blocks_count);
1590		if (sizeof(sector_t) < 8)
1591			ext4_warning(sb, "CONFIG_LBDAF not enabled");
1592		return -EINVAL;
1593	}
1594
1595	if (n_blocks_count < o_blocks_count) {
1596		ext4_warning(sb, "can't shrink FS - resize aborted");
1597		return -EINVAL;
1598	}
1599
1600	/* Handle the remaining blocks in the last group only. */
1601	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1602
1603	if (last == 0) {
1604		ext4_warning(sb, "need to use ext2online to resize further");
1605		return -EPERM;
1606	}
1607
1608	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1609
1610	if (o_blocks_count + add < o_blocks_count) {
1611		ext4_warning(sb, "blocks_count overflow");
1612		return -EINVAL;
1613	}
1614
1615	if (o_blocks_count + add > n_blocks_count)
1616		add = n_blocks_count - o_blocks_count;
1617
1618	if (o_blocks_count + add < n_blocks_count)
1619		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1620			     o_blocks_count + add, add);
1621
1622	/* See if the device is actually as big as what was requested */
1623	bh = sb_bread(sb, o_blocks_count + add - 1);
1624	if (!bh) {
1625		ext4_warning(sb, "can't read last block, resize aborted");
1626		return -ENOSPC;
1627	}
1628	brelse(bh);
1629
1630	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1631	return err;
1632} /* ext4_group_extend */
1633
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1634/*
1635 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1636 *
1637 * @sb: super block of the fs to be resized
1638 * @n_blocks_count: the number of blocks resides in the resized fs
1639 */
1640int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1641{
1642	struct ext4_new_flex_group_data *flex_gd = NULL;
1643	struct ext4_sb_info *sbi = EXT4_SB(sb);
1644	struct ext4_super_block *es = sbi->s_es;
1645	struct buffer_head *bh;
1646	struct inode *resize_inode;
1647	ext4_fsblk_t o_blocks_count;
1648	ext4_group_t o_group;
1649	ext4_group_t n_group;
1650	ext4_grpblk_t offset, add;
1651	unsigned long n_desc_blocks;
1652	unsigned long o_desc_blocks;
1653	unsigned long desc_blocks;
1654	int err = 0, flexbg_size = 1;
 
 
 
 
 
1655
 
 
 
 
 
 
 
 
 
1656	o_blocks_count = ext4_blocks_count(es);
1657
1658	if (test_opt(sb, DEBUG))
1659		ext4_msg(sb, KERN_DEBUG, "resizing filesystem from %llu "
1660		       "to %llu blocks", o_blocks_count, n_blocks_count);
1661
1662	if (n_blocks_count < o_blocks_count) {
1663		/* On-line shrinking not supported */
1664		ext4_warning(sb, "can't shrink FS - resize aborted");
1665		return -EINVAL;
1666	}
1667
1668	if (n_blocks_count == o_blocks_count)
1669		/* Nothing need to do */
1670		return 0;
1671
1672	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
 
 
 
 
1673	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1674
1675	n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
1676			EXT4_DESC_PER_BLOCK(sb);
1677	o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1678			EXT4_DESC_PER_BLOCK(sb);
1679	desc_blocks = n_desc_blocks - o_desc_blocks;
1680
1681	if (desc_blocks &&
1682	    (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
1683	     le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
1684		ext4_warning(sb, "No reserved GDT blocks, can't resize");
1685		return -EPERM;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1686	}
1687
1688	resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1689	if (IS_ERR(resize_inode)) {
1690		ext4_warning(sb, "Error opening resize inode");
1691		return PTR_ERR(resize_inode);
 
 
 
 
 
 
 
 
 
1692	}
1693
1694	/* See if the device is actually as big as what was requested */
1695	bh = sb_bread(sb, n_blocks_count - 1);
1696	if (!bh) {
1697		ext4_warning(sb, "can't read last block, resize aborted");
1698		return -ENOSPC;
 
 
 
 
 
 
 
 
 
 
 
 
 
1699	}
1700	brelse(bh);
1701
1702	/* extend the last group */
1703	if (n_group == o_group)
1704		add = n_blocks_count - o_blocks_count;
1705	else
1706		add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1707	if (add > 0) {
1708		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1709		if (err)
1710			goto out;
1711	}
1712
1713	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1714	    es->s_log_groups_per_flex)
1715		flexbg_size = 1 << es->s_log_groups_per_flex;
1716
1717	o_blocks_count = ext4_blocks_count(es);
1718	if (o_blocks_count == n_blocks_count)
 
 
 
 
1719		goto out;
1720
1721	flex_gd = alloc_flex_gd(flexbg_size);
1722	if (flex_gd == NULL) {
1723		err = -ENOMEM;
1724		goto out;
1725	}
1726
1727	/* Add flex groups. Note that a regular group is a
1728	 * flex group with 1 group.
1729	 */
1730	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1731					      flexbg_size)) {
1732		ext4_alloc_group_tables(sb, flex_gd, flexbg_size);
 
 
 
 
 
 
 
 
1733		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1734		if (unlikely(err))
1735			break;
1736	}
1737
 
 
 
 
 
 
 
 
 
 
 
 
1738out:
1739	if (flex_gd)
1740		free_flex_gd(flex_gd);
1741
1742	iput(resize_inode);
1743	if (test_opt(sb, DEBUG))
1744		ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
1745		       "upto %llu blocks", o_blocks_count, n_blocks_count);
 
 
1746	return err;
1747}