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
  48static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  49					     ext4_group_t group) {
  50	return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  51	       EXT4_DESC_PER_BLOCK_BITS(sb);
  52}
  53
  54static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  55					     ext4_group_t group) {
  56	group = ext4_meta_bg_first_group(sb, group);
  57	return ext4_group_first_block_no(sb, group);
  58}
  59
  60static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  61						ext4_group_t group) {
  62	ext4_grpblk_t overhead;
  63	overhead = ext4_bg_num_gdb(sb, group);
  64	if (ext4_bg_has_super(sb, group))
  65		overhead += 1 +
  66			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  67	return overhead;
  68}
  69
  70#define outside(b, first, last)	((b) < (first) || (b) >= (last))
  71#define inside(b, first, last)	((b) >= (first) && (b) < (last))
  72
  73static int verify_group_input(struct super_block *sb,
  74			      struct ext4_new_group_data *input)
  75{
  76	struct ext4_sb_info *sbi = EXT4_SB(sb);
  77	struct ext4_super_block *es = sbi->s_es;
  78	ext4_fsblk_t start = ext4_blocks_count(es);
  79	ext4_fsblk_t end = start + input->blocks_count;
  80	ext4_group_t group = input->group;
  81	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  82	unsigned overhead;
  83	ext4_fsblk_t metaend;
  84	struct buffer_head *bh = NULL;
  85	ext4_grpblk_t free_blocks_count, offset;
  86	int err = -EINVAL;
  87
  88	if (group != sbi->s_groups_count) {
  89		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
  90			     input->group, sbi->s_groups_count);
  91		return -EINVAL;
  92	}
  93
  94	overhead = ext4_group_overhead_blocks(sb, group);
  95	metaend = start + overhead;
  96	input->free_blocks_count = free_blocks_count =
  97		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 
  98
  99	if (test_opt(sb, DEBUG))
 100		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 101		       "(%d free, %u reserved)\n",
 102		       ext4_bg_has_super(sb, input->group) ? "normal" :
 103		       "no-super", input->group, input->blocks_count,
 104		       free_blocks_count, input->reserved_blocks);
 105
 106	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 107	if (offset != 0)
 108			ext4_warning(sb, "Last group not full");
 109	else if (input->reserved_blocks > input->blocks_count / 5)
 110		ext4_warning(sb, "Reserved blocks too high (%u)",
 111			     input->reserved_blocks);
 112	else if (free_blocks_count < 0)
 113		ext4_warning(sb, "Bad blocks count %u",
 114			     input->blocks_count);
 115	else if (!(bh = sb_bread(sb, end - 1)))
 
 
 116		ext4_warning(sb, "Cannot read last block (%llu)",
 117			     end - 1);
 118	else if (outside(input->block_bitmap, start, end))
 119		ext4_warning(sb, "Block bitmap not in group (block %llu)",
 120			     (unsigned long long)input->block_bitmap);
 121	else if (outside(input->inode_bitmap, start, end))
 122		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 123			     (unsigned long long)input->inode_bitmap);
 124	else if (outside(input->inode_table, start, end) ||
 125		 outside(itend - 1, start, end))
 126		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 127			     (unsigned long long)input->inode_table, itend - 1);
 128	else if (input->inode_bitmap == input->block_bitmap)
 129		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 130			     (unsigned long long)input->block_bitmap);
 131	else if (inside(input->block_bitmap, input->inode_table, itend))
 132		ext4_warning(sb, "Block bitmap (%llu) in inode table "
 133			     "(%llu-%llu)",
 134			     (unsigned long long)input->block_bitmap,
 135			     (unsigned long long)input->inode_table, itend - 1);
 136	else if (inside(input->inode_bitmap, input->inode_table, itend))
 137		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 138			     "(%llu-%llu)",
 139			     (unsigned long long)input->inode_bitmap,
 140			     (unsigned long long)input->inode_table, itend - 1);
 141	else if (inside(input->block_bitmap, start, metaend))
 142		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 143			     (unsigned long long)input->block_bitmap,
 144			     start, metaend - 1);
 145	else if (inside(input->inode_bitmap, start, metaend))
 146		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 147			     (unsigned long long)input->inode_bitmap,
 148			     start, metaend - 1);
 149	else if (inside(input->inode_table, start, metaend) ||
 150		 inside(itend - 1, start, metaend))
 151		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 152			     "(%llu-%llu)",
 153			     (unsigned long long)input->inode_table,
 154			     itend - 1, start, metaend - 1);
 155	else
 156		err = 0;
 157	brelse(bh);
 158
 159	return err;
 160}
 161
 162/*
 163 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 164 * group each time.
 165 */
 166struct ext4_new_flex_group_data {
 167	struct ext4_new_group_data *groups;	/* new_group_data for groups
 168						   in the flex group */
 169	__u16 *bg_flags;			/* block group flags of groups
 170						   in @groups */
 
 
 171	ext4_group_t count;			/* number of groups in @groups
 172						 */
 173};
 174
 175/*
 
 
 
 
 
 176 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 177 * @flexbg_size.
 178 *
 179 * Returns NULL on failure otherwise address of the allocated structure.
 180 */
 181static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 
 182{
 
 183	struct ext4_new_flex_group_data *flex_gd;
 184
 185	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 186	if (flex_gd == NULL)
 187		goto out3;
 188
 189	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
 190		goto out2;
 191	flex_gd->count = flexbg_size;
 
 192
 193	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 194				  flexbg_size, GFP_NOFS);
 
 
 
 
 
 
 
 
 
 195	if (flex_gd->groups == NULL)
 196		goto out2;
 197
 198	flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 
 199	if (flex_gd->bg_flags == NULL)
 200		goto out1;
 201
 202	return flex_gd;
 203
 204out1:
 205	kfree(flex_gd->groups);
 206out2:
 207	kfree(flex_gd);
 208out3:
 209	return NULL;
 210}
 211
 212static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 213{
 214	kfree(flex_gd->bg_flags);
 215	kfree(flex_gd->groups);
 216	kfree(flex_gd);
 217}
 218
 219/*
 220 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 221 * and inode tables for a flex group.
 222 *
 223 * This function is used by 64bit-resize.  Note that this function allocates
 224 * group tables from the 1st group of groups contained by @flexgd, which may
 225 * be a partial of a flex group.
 226 *
 227 * @sb: super block of fs to which the groups belongs
 228 *
 229 * Returns 0 on a successful allocation of the metadata blocks in the
 230 * block group.
 231 */
 232static int ext4_alloc_group_tables(struct super_block *sb,
 233				struct ext4_new_flex_group_data *flex_gd,
 234				int flexbg_size)
 235{
 236	struct ext4_new_group_data *group_data = flex_gd->groups;
 237	ext4_fsblk_t start_blk;
 238	ext4_fsblk_t last_blk;
 239	ext4_group_t src_group;
 240	ext4_group_t bb_index = 0;
 241	ext4_group_t ib_index = 0;
 242	ext4_group_t it_index = 0;
 243	ext4_group_t group;
 244	ext4_group_t last_group;
 245	unsigned overhead;
 246	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 
 247
 248	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 249
 250	src_group = group_data[0].group;
 251	last_group  = src_group + flex_gd->count - 1;
 252
 253	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 254	       (last_group & ~(flexbg_size - 1))));
 255next_group:
 256	group = group_data[0].group;
 257	if (src_group >= group_data[0].group + flex_gd->count)
 258		return -ENOSPC;
 259	start_blk = ext4_group_first_block_no(sb, src_group);
 260	last_blk = start_blk + group_data[src_group - group].blocks_count;
 261
 262	overhead = ext4_group_overhead_blocks(sb, src_group);
 263
 264	start_blk += overhead;
 265
 266	/* We collect contiguous blocks as much as possible. */
 267	src_group++;
 268	for (; src_group <= last_group; src_group++) {
 269		overhead = ext4_group_overhead_blocks(sb, src_group);
 270		if (overhead == 0)
 271			last_blk += group_data[src_group - group].blocks_count;
 272		else
 273			break;
 274	}
 275
 276	/* Allocate block bitmaps */
 277	for (; bb_index < flex_gd->count; bb_index++) {
 278		if (start_blk >= last_blk)
 279			goto next_group;
 280		group_data[bb_index].block_bitmap = start_blk++;
 281		group = ext4_get_group_number(sb, start_blk - 1);
 282		group -= group_data[0].group;
 283		group_data[group].free_blocks_count--;
 284		flex_gd->bg_flags[group] &= uninit_mask;
 285	}
 286
 287	/* Allocate inode bitmaps */
 288	for (; ib_index < flex_gd->count; ib_index++) {
 289		if (start_blk >= last_blk)
 290			goto next_group;
 291		group_data[ib_index].inode_bitmap = start_blk++;
 292		group = ext4_get_group_number(sb, start_blk - 1);
 293		group -= group_data[0].group;
 294		group_data[group].free_blocks_count--;
 295		flex_gd->bg_flags[group] &= uninit_mask;
 296	}
 297
 298	/* Allocate inode tables */
 299	for (; it_index < flex_gd->count; it_index++) {
 300		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 301		ext4_fsblk_t next_group_start;
 302
 303		if (start_blk + itb > last_blk)
 304			goto next_group;
 305		group_data[it_index].inode_table = start_blk;
 306		group = ext4_get_group_number(sb, start_blk);
 307		next_group_start = ext4_group_first_block_no(sb, group + 1);
 308		group -= group_data[0].group;
 309
 310		if (start_blk + itb > next_group_start) {
 311			flex_gd->bg_flags[group + 1] &= uninit_mask;
 312			overhead = start_blk + itb - next_group_start;
 313			group_data[group + 1].free_blocks_count -= overhead;
 314			itb -= overhead;
 315		}
 316
 317		group_data[group].free_blocks_count -= itb;
 318		flex_gd->bg_flags[group] &= uninit_mask;
 319		start_blk += EXT4_SB(sb)->s_itb_per_group;
 320	}
 321
 
 
 
 
 
 
 
 322	if (test_opt(sb, DEBUG)) {
 323		int i;
 324		group = group_data[0].group;
 325
 326		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 327		       "%d groups, flexbg size is %d:\n", flex_gd->count,
 328		       flexbg_size);
 329
 330		for (i = 0; i < flex_gd->count; i++) {
 331			printk(KERN_DEBUG "adding %s group %u: %u "
 332			       "blocks (%d free)\n",
 333			       ext4_bg_has_super(sb, group + i) ? "normal" :
 334			       "no-super", group + i,
 335			       group_data[i].blocks_count,
 336			       group_data[i].free_blocks_count);
 
 337		}
 338	}
 339	return 0;
 340}
 341
 342static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 343				  ext4_fsblk_t blk)
 344{
 345	struct buffer_head *bh;
 346	int err;
 347
 348	bh = sb_getblk(sb, blk);
 349	if (unlikely(!bh))
 350		return ERR_PTR(-ENOMEM);
 351	if ((err = ext4_journal_get_write_access(handle, bh))) {
 
 
 352		brelse(bh);
 353		bh = ERR_PTR(err);
 354	} else {
 355		memset(bh->b_data, 0, sb->s_blocksize);
 356		set_buffer_uptodate(bh);
 357	}
 358
 359	return bh;
 360}
 361
 362/*
 363 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 364 * If that fails, restart the transaction & regain write access for the
 365 * buffer head which is used for block_bitmap modifications.
 366 */
 367static int extend_or_restart_transaction(handle_t *handle, int thresh)
 368{
 369	int err;
 370
 371	if (ext4_handle_has_enough_credits(handle, thresh))
 372		return 0;
 373
 374	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 375	if (err < 0)
 376		return err;
 377	if (err) {
 378		err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 379		if (err)
 380			return err;
 381	}
 382
 383	return 0;
 384}
 385
 386/*
 387 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 388 *
 389 * Helper function for ext4_setup_new_group_blocks() which set .
 390 *
 391 * @sb: super block
 392 * @handle: journal handle
 393 * @flex_gd: flex group data
 394 */
 395static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 396			struct ext4_new_flex_group_data *flex_gd,
 397			ext4_fsblk_t block, ext4_group_t count)
 398{
 
 
 399	ext4_group_t count2;
 400
 401	ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 402	for (count2 = count; count > 0; count -= count2, block += count2) {
 
 403		ext4_fsblk_t start;
 404		struct buffer_head *bh;
 405		ext4_group_t group;
 406		int err;
 407
 408		group = ext4_get_group_number(sb, block);
 409		start = ext4_group_first_block_no(sb, group);
 410		group -= flex_gd->groups[0].group;
 411
 412		count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
 413		if (count2 > count)
 414			count2 = count;
 415
 416		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 417			BUG_ON(flex_gd->count > 1);
 418			continue;
 419		}
 420
 421		err = extend_or_restart_transaction(handle, 1);
 422		if (err)
 423			return err;
 424
 425		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 426		if (unlikely(!bh))
 427			return -ENOMEM;
 428
 429		err = ext4_journal_get_write_access(handle, bh);
 430		if (err)
 
 
 
 431			return err;
 432		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 433			   block - start, count2);
 434		ext4_set_bits(bh->b_data, block - start, count2);
 
 435
 436		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 437		if (unlikely(err))
 438			return err;
 439		brelse(bh);
 440	}
 441
 442	return 0;
 443}
 444
 445/*
 446 * Set up the block and inode bitmaps, and the inode table for the new groups.
 447 * This doesn't need to be part of the main transaction, since we are only
 448 * changing blocks outside the actual filesystem.  We still do journaling to
 449 * ensure the recovery is correct in case of a failure just after resize.
 450 * If any part of this fails, we simply abort the resize.
 451 *
 452 * setup_new_flex_group_blocks handles a flex group as follow:
 453 *  1. copy super block and GDT, and initialize group tables if necessary.
 454 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 455 *     super block and GDT.
 456 *  2. allocate group tables in block bitmaps, that is, set bits in block
 457 *     bitmap for blocks taken by group tables.
 458 */
 459static int setup_new_flex_group_blocks(struct super_block *sb,
 460				struct ext4_new_flex_group_data *flex_gd)
 461{
 462	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 463	ext4_fsblk_t start;
 464	ext4_fsblk_t block;
 465	struct ext4_sb_info *sbi = EXT4_SB(sb);
 466	struct ext4_super_block *es = sbi->s_es;
 467	struct ext4_new_group_data *group_data = flex_gd->groups;
 468	__u16 *bg_flags = flex_gd->bg_flags;
 469	handle_t *handle;
 470	ext4_group_t group, count;
 471	struct buffer_head *bh = NULL;
 472	int reserved_gdb, i, j, err = 0, err2;
 473	int meta_bg;
 474
 475	BUG_ON(!flex_gd->count || !group_data ||
 476	       group_data[0].group != sbi->s_groups_count);
 477
 478	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 479	meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
 480
 481	/* This transaction may be extended/restarted along the way */
 482	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 483	if (IS_ERR(handle))
 484		return PTR_ERR(handle);
 485
 486	group = group_data[0].group;
 487	for (i = 0; i < flex_gd->count; i++, group++) {
 488		unsigned long gdblocks;
 489		ext4_grpblk_t overhead;
 490
 491		gdblocks = ext4_bg_num_gdb(sb, group);
 492		start = ext4_group_first_block_no(sb, group);
 493
 494		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 495			goto handle_itb;
 496
 497		if (meta_bg == 1) {
 498			ext4_group_t first_group;
 499			first_group = ext4_meta_bg_first_group(sb, group);
 500			if (first_group != group + 1 &&
 501			    first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 502				goto handle_itb;
 503		}
 504
 505		block = start + ext4_bg_has_super(sb, group);
 506		/* Copy all of the GDT blocks into the backup in this group */
 507		for (j = 0; j < gdblocks; j++, block++) {
 508			struct buffer_head *gdb;
 509
 510			ext4_debug("update backup group %#04llx\n", block);
 511			err = extend_or_restart_transaction(handle, 1);
 512			if (err)
 513				goto out;
 514
 515			gdb = sb_getblk(sb, block);
 516			if (unlikely(!gdb)) {
 517				err = -ENOMEM;
 518				goto out;
 519			}
 520
 521			err = ext4_journal_get_write_access(handle, gdb);
 
 
 522			if (err) {
 523				brelse(gdb);
 524				goto out;
 525			}
 526			memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 527			       gdb->b_size);
 528			set_buffer_uptodate(gdb);
 529
 530			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 531			if (unlikely(err)) {
 532				brelse(gdb);
 533				goto out;
 534			}
 535			brelse(gdb);
 536		}
 537
 538		/* Zero out all of the reserved backup group descriptor
 539		 * table blocks
 540		 */
 541		if (ext4_bg_has_super(sb, group)) {
 542			err = sb_issue_zeroout(sb, gdblocks + start + 1,
 543					reserved_gdb, GFP_NOFS);
 544			if (err)
 545				goto out;
 546		}
 547
 548handle_itb:
 549		/* Initialize group tables of the grop @group */
 550		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 551			goto handle_bb;
 552
 553		/* Zero out all of the inode table blocks */
 554		block = group_data[i].inode_table;
 555		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 556			   block, sbi->s_itb_per_group);
 557		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 558				       GFP_NOFS);
 559		if (err)
 560			goto out;
 561
 562handle_bb:
 563		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 564			goto handle_ib;
 565
 566		/* Initialize block bitmap of the @group */
 567		block = group_data[i].block_bitmap;
 568		err = extend_or_restart_transaction(handle, 1);
 569		if (err)
 570			goto out;
 571
 572		bh = bclean(handle, sb, block);
 573		if (IS_ERR(bh)) {
 574			err = PTR_ERR(bh);
 575			goto out;
 576		}
 577		overhead = ext4_group_overhead_blocks(sb, group);
 578		if (overhead != 0) {
 579			ext4_debug("mark backup superblock %#04llx (+0)\n",
 580				   start);
 581			ext4_set_bits(bh->b_data, 0, overhead);
 
 582		}
 583		ext4_mark_bitmap_end(group_data[i].blocks_count,
 584				     sb->s_blocksize * 8, bh->b_data);
 585		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 586		if (err)
 587			goto out;
 588		brelse(bh);
 589
 590handle_ib:
 591		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 592			continue;
 593
 594		/* Initialize inode bitmap of the @group */
 595		block = group_data[i].inode_bitmap;
 596		err = extend_or_restart_transaction(handle, 1);
 597		if (err)
 598			goto out;
 599		/* Mark unused entries in inode bitmap used */
 600		bh = bclean(handle, sb, block);
 601		if (IS_ERR(bh)) {
 602			err = PTR_ERR(bh);
 603			goto out;
 604		}
 605
 606		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 607				     sb->s_blocksize * 8, bh->b_data);
 608		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 
 609		if (err)
 610			goto out;
 611		brelse(bh);
 612	}
 613	bh = NULL;
 614
 615	/* Mark group tables in block bitmap */
 616	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 617		count = group_table_count[j];
 618		start = (&group_data[0].block_bitmap)[j];
 619		block = start;
 620		for (i = 1; i < flex_gd->count; i++) {
 621			block += group_table_count[j];
 622			if (block == (&group_data[i].block_bitmap)[j]) {
 623				count += group_table_count[j];
 624				continue;
 625			}
 626			err = set_flexbg_block_bitmap(sb, handle,
 627						flex_gd, start, count);
 
 
 
 
 628			if (err)
 629				goto out;
 630			count = group_table_count[j];
 631			start = (&group_data[i].block_bitmap)[j];
 632			block = start;
 633		}
 634
 635		if (count) {
 636			err = set_flexbg_block_bitmap(sb, handle,
 637						flex_gd, start, count);
 638			if (err)
 639				goto out;
 640		}
 
 
 641	}
 642
 643out:
 644	brelse(bh);
 645	err2 = ext4_journal_stop(handle);
 646	if (err2 && !err)
 647		err = err2;
 648
 649	return err;
 650}
 651
 652/*
 653 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 654 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 655 * calling this for the first time.  In a sparse filesystem it will be the
 656 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 657 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 658 */
 659static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 660				  unsigned *five, unsigned *seven)
 661{
 662	unsigned *min = three;
 
 663	int mult = 3;
 664	unsigned ret;
 665
 666	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 667					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 
 
 
 
 
 
 
 
 
 668		ret = *min;
 669		*min += 1;
 670		return ret;
 671	}
 672
 673	if (*five < *min) {
 674		min = five;
 675		mult = 5;
 676	}
 677	if (*seven < *min) {
 678		min = seven;
 679		mult = 7;
 680	}
 681
 682	ret = *min;
 683	*min *= mult;
 684
 685	return ret;
 686}
 687
 688/*
 689 * Check that all of the backup GDT blocks are held in the primary GDT block.
 690 * It is assumed that they are stored in group order.  Returns the number of
 691 * groups in current filesystem that have BACKUPS, or -ve error code.
 692 */
 693static int verify_reserved_gdb(struct super_block *sb,
 694			       ext4_group_t end,
 695			       struct buffer_head *primary)
 696{
 697	const ext4_fsblk_t blk = primary->b_blocknr;
 698	unsigned three = 1;
 699	unsigned five = 5;
 700	unsigned seven = 7;
 701	unsigned grp;
 702	__le32 *p = (__le32 *)primary->b_data;
 703	int gdbackups = 0;
 704
 705	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 706		if (le32_to_cpu(*p++) !=
 707		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 708			ext4_warning(sb, "reserved GDT %llu"
 709				     " missing grp %d (%llu)",
 710				     blk, grp,
 711				     grp *
 712				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 713				     blk);
 714			return -EINVAL;
 715		}
 716		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 717			return -EFBIG;
 718	}
 719
 720	return gdbackups;
 721}
 722
 723/*
 724 * Called when we need to bring a reserved group descriptor table block into
 725 * use from the resize inode.  The primary copy of the new GDT block currently
 726 * is an indirect block (under the double indirect block in the resize inode).
 727 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 728 * block, in group order.  Even though we know all the block numbers we need,
 729 * we check to ensure that the resize inode has actually reserved these blocks.
 730 *
 731 * Don't need to update the block bitmaps because the blocks are still in use.
 732 *
 733 * We get all of the error cases out of the way, so that we are sure to not
 734 * fail once we start modifying the data on disk, because JBD has no rollback.
 735 */
 736static int add_new_gdb(handle_t *handle, struct inode *inode,
 737		       ext4_group_t group)
 738{
 739	struct super_block *sb = inode->i_sb;
 740	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 741	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 742	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 743	struct buffer_head **o_group_desc, **n_group_desc;
 744	struct buffer_head *dind;
 745	struct buffer_head *gdb_bh;
 746	int gdbackups;
 747	struct ext4_iloc iloc;
 748	__le32 *data;
 749	int err;
 750
 751	if (test_opt(sb, DEBUG))
 752		printk(KERN_DEBUG
 753		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 754		       gdb_num);
 755
 756	/*
 757	 * If we are not using the primary superblock/GDT copy don't resize,
 758         * because the user tools have no way of handling this.  Probably a
 759         * bad time to do it anyways.
 760         */
 761	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 762	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 763		ext4_warning(sb, "won't resize using backup superblock at %llu",
 764			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 765		return -EPERM;
 766	}
 767
 768	gdb_bh = sb_bread(sb, gdblock);
 769	if (!gdb_bh)
 770		return -EIO;
 771
 772	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 773	if (gdbackups < 0) {
 774		err = gdbackups;
 775		goto exit_bh;
 776	}
 777
 778	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 779	dind = sb_bread(sb, le32_to_cpu(*data));
 780	if (!dind) {
 781		err = -EIO;
 782		goto exit_bh;
 
 783	}
 784
 785	data = (__le32 *)dind->b_data;
 786	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 787		ext4_warning(sb, "new group %u GDT block %llu not reserved",
 788			     group, gdblock);
 789		err = -EINVAL;
 790		goto exit_dind;
 791	}
 792
 793	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 
 
 794	if (unlikely(err))
 795		goto exit_dind;
 796
 797	err = ext4_journal_get_write_access(handle, gdb_bh);
 
 798	if (unlikely(err))
 799		goto exit_dind;
 800
 801	err = ext4_journal_get_write_access(handle, dind);
 802	if (unlikely(err))
 
 803		ext4_std_error(sb, err);
 
 
 804
 805	/* ext4_reserve_inode_write() gets a reference on the iloc */
 806	err = ext4_reserve_inode_write(handle, inode, &iloc);
 807	if (unlikely(err))
 808		goto exit_dind;
 809
 810	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 811				     sizeof(struct buffer_head *),
 812				     GFP_NOFS);
 813	if (!n_group_desc) {
 814		err = -ENOMEM;
 815		ext4_warning(sb, "not enough memory for %lu groups",
 816			     gdb_num + 1);
 817		goto exit_inode;
 818	}
 819
 820	/*
 821	 * Finally, we have all of the possible failures behind us...
 822	 *
 823	 * Remove new GDT block from inode double-indirect block and clear out
 824	 * the new GDT block for use (which also "frees" the backup GDT blocks
 825	 * from the reserved inode).  We don't need to change the bitmaps for
 826	 * these blocks, because they are marked as in-use from being in the
 827	 * reserved inode, and will become GDT blocks (primary and backup).
 828	 */
 829	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 830	err = ext4_handle_dirty_metadata(handle, NULL, dind);
 831	if (unlikely(err)) {
 832		ext4_std_error(sb, err);
 833		goto exit_inode;
 834	}
 835	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 
 836	ext4_mark_iloc_dirty(handle, inode, &iloc);
 837	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 838	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 839	if (unlikely(err)) {
 840		ext4_std_error(sb, err);
 841		goto exit_inode;
 
 842	}
 843	brelse(dind);
 844
 845	o_group_desc = EXT4_SB(sb)->s_group_desc;
 
 846	memcpy(n_group_desc, o_group_desc,
 847	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 
 848	n_group_desc[gdb_num] = gdb_bh;
 849	EXT4_SB(sb)->s_group_desc = n_group_desc;
 850	EXT4_SB(sb)->s_gdb_count++;
 851	ext4_kvfree(o_group_desc);
 852
 
 853	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 854	err = ext4_handle_dirty_super(handle, sb);
 
 
 855	if (err)
 856		ext4_std_error(sb, err);
 857
 858	return err;
 859
 860exit_inode:
 861	ext4_kvfree(n_group_desc);
 862	brelse(iloc.bh);
 863exit_dind:
 864	brelse(dind);
 865exit_bh:
 866	brelse(gdb_bh);
 867
 868	ext4_debug("leaving with error %d\n", err);
 869	return err;
 870}
 871
 872/*
 873 * add_new_gdb_meta_bg is the sister of add_new_gdb.
 
 
 
 
 
 
 874 */
 875static int add_new_gdb_meta_bg(struct super_block *sb,
 876			       handle_t *handle, ext4_group_t group) {
 877	ext4_fsblk_t gdblock;
 878	struct buffer_head *gdb_bh;
 879	struct buffer_head **o_group_desc, **n_group_desc;
 880	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 881	int err;
 882
 883	gdblock = ext4_meta_bg_first_block_no(sb, group) +
 884		   ext4_bg_has_super(sb, group);
 885	gdb_bh = sb_bread(sb, gdblock);
 886	if (!gdb_bh)
 887		return -EIO;
 888	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 889				     sizeof(struct buffer_head *),
 890				     GFP_NOFS);
 891	if (!n_group_desc) {
 
 892		err = -ENOMEM;
 893		ext4_warning(sb, "not enough memory for %lu groups",
 894			     gdb_num + 1);
 895		return err;
 896	}
 897
 898	o_group_desc = EXT4_SB(sb)->s_group_desc;
 
 899	memcpy(n_group_desc, o_group_desc,
 900	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 
 901	n_group_desc[gdb_num] = gdb_bh;
 902	EXT4_SB(sb)->s_group_desc = n_group_desc;
 903	EXT4_SB(sb)->s_gdb_count++;
 904	ext4_kvfree(o_group_desc);
 905	err = ext4_journal_get_write_access(handle, gdb_bh);
 906	if (unlikely(err))
 907		brelse(gdb_bh);
 
 
 
 
 
 
 908	return err;
 909}
 910
 911/*
 912 * Called when we are adding a new group which has a backup copy of each of
 913 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 914 * We need to add these reserved backup GDT blocks to the resize inode, so
 915 * that they are kept for future resizing and not allocated to files.
 916 *
 917 * Each reserved backup GDT block will go into a different indirect block.
 918 * The indirect blocks are actually the primary reserved GDT blocks,
 919 * so we know in advance what their block numbers are.  We only get the
 920 * double-indirect block to verify it is pointing to the primary reserved
 921 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 922 * backup GDT blocks are stored in their reserved primary GDT block.
 923 */
 924static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 925			      ext4_group_t group)
 926{
 927	struct super_block *sb = inode->i_sb;
 928	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 
 929	struct buffer_head **primary;
 930	struct buffer_head *dind;
 931	struct ext4_iloc iloc;
 932	ext4_fsblk_t blk;
 933	__le32 *data, *end;
 934	int gdbackups = 0;
 935	int res, i;
 936	int err;
 937
 938	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 939	if (!primary)
 940		return -ENOMEM;
 941
 942	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 943	dind = sb_bread(sb, le32_to_cpu(*data));
 944	if (!dind) {
 945		err = -EIO;
 
 946		goto exit_free;
 947	}
 948
 949	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 950	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 951					 EXT4_ADDR_PER_BLOCK(sb));
 952	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 953
 954	/* Get each reserved primary GDT block and verify it holds backups */
 955	for (res = 0; res < reserved_gdb; res++, blk++) {
 956		if (le32_to_cpu(*data) != blk) {
 957			ext4_warning(sb, "reserved block %llu"
 958				     " not at offset %ld",
 959				     blk,
 960				     (long)(data - (__le32 *)dind->b_data));
 961			err = -EINVAL;
 962			goto exit_bh;
 963		}
 964		primary[res] = sb_bread(sb, blk);
 965		if (!primary[res]) {
 966			err = -EIO;
 
 967			goto exit_bh;
 968		}
 969		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 970		if (gdbackups < 0) {
 971			brelse(primary[res]);
 972			err = gdbackups;
 973			goto exit_bh;
 974		}
 975		if (++data >= end)
 976			data = (__le32 *)dind->b_data;
 977	}
 978
 979	for (i = 0; i < reserved_gdb; i++) {
 980		if ((err = ext4_journal_get_write_access(handle, primary[i])))
 
 
 981			goto exit_bh;
 982	}
 983
 984	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 985		goto exit_bh;
 986
 987	/*
 988	 * Finally we can add each of the reserved backup GDT blocks from
 989	 * the new group to its reserved primary GDT block.
 990	 */
 991	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
 992	for (i = 0; i < reserved_gdb; i++) {
 993		int err2;
 994		data = (__le32 *)primary[i]->b_data;
 995		/* printk("reserving backup %lu[%u] = %lu\n",
 996		       primary[i]->b_blocknr, gdbackups,
 997		       blk + primary[i]->b_blocknr); */
 998		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 999		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1000		if (!err)
1001			err = err2;
1002	}
1003	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
 
1004	ext4_mark_iloc_dirty(handle, inode, &iloc);
1005
1006exit_bh:
1007	while (--res >= 0)
1008		brelse(primary[res]);
1009	brelse(dind);
1010
1011exit_free:
1012	kfree(primary);
1013
1014	return err;
1015}
1016
 
 
 
 
 
 
 
 
 
 
1017/*
1018 * Update the backup copies of the ext4 metadata.  These don't need to be part
1019 * of the main resize transaction, because e2fsck will re-write them if there
1020 * is a problem (basically only OOM will cause a problem).  However, we
1021 * _should_ update the backups if possible, in case the primary gets trashed
1022 * for some reason and we need to run e2fsck from a backup superblock.  The
1023 * important part is that the new block and inode counts are in the backup
1024 * superblocks, and the location of the new group metadata in the GDT backups.
1025 *
1026 * We do not need take the s_resize_lock for this, because these
1027 * blocks are not otherwise touched by the filesystem code when it is
1028 * mounted.  We don't need to worry about last changing from
1029 * sbi->s_groups_count, because the worst that can happen is that we
1030 * do not copy the full number of backups at this time.  The resize
1031 * which changed s_groups_count will backup again.
1032 */
1033static void update_backups(struct super_block *sb, int blk_off, char *data,
1034			   int size, int meta_bg)
1035{
1036	struct ext4_sb_info *sbi = EXT4_SB(sb);
1037	ext4_group_t last;
1038	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1039	unsigned three = 1;
1040	unsigned five = 5;
1041	unsigned seven = 7;
1042	ext4_group_t group = 0;
1043	int rest = sb->s_blocksize - size;
1044	handle_t *handle;
1045	int err = 0, err2;
1046
1047	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1048	if (IS_ERR(handle)) {
1049		group = 1;
1050		err = PTR_ERR(handle);
1051		goto exit_err;
1052	}
1053
1054	if (meta_bg == 0) {
1055		group = ext4_list_backups(sb, &three, &five, &seven);
1056		last = sbi->s_groups_count;
1057	} else {
1058		group = ext4_meta_bg_first_group(sb, group) + 1;
1059		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1060	}
1061
1062	while (group < sbi->s_groups_count) {
1063		struct buffer_head *bh;
1064		ext4_fsblk_t backup_block;
 
 
1065
1066		/* Out of journal space, and can't get more - abort - so sad */
1067		if (ext4_handle_valid(handle) &&
1068		    handle->h_buffer_credits == 0 &&
1069		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1070		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1071			break;
1072
1073		if (meta_bg == 0)
1074			backup_block = group * bpg + blk_off;
1075		else
1076			backup_block = (ext4_group_first_block_no(sb, group) +
1077					ext4_bg_has_super(sb, group));
1078
1079		bh = sb_getblk(sb, backup_block);
1080		if (unlikely(!bh)) {
1081			err = -ENOMEM;
1082			break;
1083		}
1084		ext4_debug("update metadata backup %llu(+%llu)\n",
1085			   backup_block, backup_block -
1086			   ext4_group_first_block_no(sb, group));
1087		if ((err = ext4_journal_get_write_access(handle, bh)))
 
 
 
1088			break;
 
1089		lock_buffer(bh);
1090		memcpy(bh->b_data, data, size);
1091		if (rest)
1092			memset(bh->b_data + size, 0, rest);
 
 
1093		set_buffer_uptodate(bh);
1094		unlock_buffer(bh);
1095		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1096		if (unlikely(err))
1097			ext4_std_error(sb, err);
1098		brelse(bh);
1099
1100		if (meta_bg == 0)
1101			group = ext4_list_backups(sb, &three, &five, &seven);
1102		else if (group == last)
1103			break;
1104		else
1105			group = last;
1106	}
1107	if ((err2 = ext4_journal_stop(handle)) && !err)
1108		err = err2;
1109
1110	/*
1111	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1112	 * late to revert the resize, we shouldn't fail just because of
1113	 * the backup copies (they are only needed in case of corruption).
1114	 *
1115	 * However, if we got here we have a journal problem too, so we
1116	 * can't really start a transaction to mark the superblock.
1117	 * Chicken out and just set the flag on the hope it will be written
1118	 * to disk, and if not - we will simply wait until next fsck.
1119	 */
1120exit_err:
1121	if (err) {
1122		ext4_warning(sb, "can't update backup for group %u (err %d), "
1123			     "forcing fsck on next reboot", group, err);
1124		sbi->s_mount_state &= ~EXT4_VALID_FS;
1125		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1126		mark_buffer_dirty(sbi->s_sbh);
1127	}
1128}
1129
1130/*
1131 * ext4_add_new_descs() adds @count group descriptor of groups
1132 * starting at @group
1133 *
1134 * @handle: journal handle
1135 * @sb: super block
1136 * @group: the group no. of the first group desc to be added
1137 * @resize_inode: the resize inode
1138 * @count: number of group descriptors to be added
1139 */
1140static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1141			      ext4_group_t group, struct inode *resize_inode,
1142			      ext4_group_t count)
1143{
1144	struct ext4_sb_info *sbi = EXT4_SB(sb);
1145	struct ext4_super_block *es = sbi->s_es;
1146	struct buffer_head *gdb_bh;
1147	int i, gdb_off, gdb_num, err = 0;
1148	int meta_bg;
1149
1150	meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1151	for (i = 0; i < count; i++, group++) {
1152		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1153			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1154
1155		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1156		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1157
1158		/*
1159		 * We will only either add reserved group blocks to a backup group
1160		 * or remove reserved blocks for the first group in a new group block.
1161		 * Doing both would be mean more complex code, and sane people don't
1162		 * use non-sparse filesystems anymore.  This is already checked above.
1163		 */
1164		if (gdb_off) {
1165			gdb_bh = sbi->s_group_desc[gdb_num];
1166			err = ext4_journal_get_write_access(handle, gdb_bh);
 
 
 
1167
1168			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1169				err = reserve_backup_gdb(handle, resize_inode, group);
1170		} else if (meta_bg != 0) {
1171			err = add_new_gdb_meta_bg(sb, handle, group);
1172		} else {
1173			err = add_new_gdb(handle, resize_inode, group);
1174		}
1175		if (err)
1176			break;
1177	}
1178	return err;
1179}
1180
1181static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1182{
1183	struct buffer_head *bh = sb_getblk(sb, block);
1184	if (unlikely(!bh))
1185		return NULL;
1186	if (!bh_uptodate_or_lock(bh)) {
1187		if (bh_submit_read(bh) < 0) {
1188			brelse(bh);
1189			return NULL;
1190		}
1191	}
1192
1193	return bh;
1194}
1195
1196static int ext4_set_bitmap_checksums(struct super_block *sb,
1197				     ext4_group_t group,
1198				     struct ext4_group_desc *gdp,
1199				     struct ext4_new_group_data *group_data)
1200{
1201	struct buffer_head *bh;
1202
1203	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1204					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1205		return 0;
1206
1207	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1208	if (!bh)
1209		return -EIO;
1210	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1211				   EXT4_INODES_PER_GROUP(sb) / 8);
1212	brelse(bh);
1213
1214	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1215	if (!bh)
1216		return -EIO;
1217	ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1218	brelse(bh);
1219
1220	return 0;
1221}
1222
1223/*
1224 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1225 */
1226static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1227				struct ext4_new_flex_group_data *flex_gd)
1228{
1229	struct ext4_new_group_data	*group_data = flex_gd->groups;
1230	struct ext4_group_desc		*gdp;
1231	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1232	struct buffer_head		*gdb_bh;
1233	ext4_group_t			group;
1234	__u16				*bg_flags = flex_gd->bg_flags;
1235	int				i, gdb_off, gdb_num, err = 0;
1236	
1237
1238	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1239		group = group_data->group;
1240
1241		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1242		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1243
1244		/*
1245		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1246		 */
1247		gdb_bh = sbi->s_group_desc[gdb_num];
1248		/* Update group descriptor block for new group */
1249		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1250						 gdb_off * EXT4_DESC_SIZE(sb));
1251
1252		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1253		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1254		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1255		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1256		if (err) {
1257			ext4_std_error(sb, err);
1258			break;
1259		}
1260
1261		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1262		ext4_free_group_clusters_set(sb, gdp,
1263			EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1264		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1265		if (ext4_has_group_desc_csum(sb))
1266			ext4_itable_unused_set(sb, gdp,
1267					       EXT4_INODES_PER_GROUP(sb));
1268		gdp->bg_flags = cpu_to_le16(*bg_flags);
1269		ext4_group_desc_csum_set(sb, group, gdp);
1270
1271		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1272		if (unlikely(err)) {
1273			ext4_std_error(sb, err);
1274			break;
1275		}
1276
1277		/*
1278		 * We can allocate memory for mb_alloc based on the new group
1279		 * descriptor
1280		 */
1281		err = ext4_mb_add_groupinfo(sb, group, gdp);
1282		if (err)
1283			break;
1284	}
1285	return err;
1286}
1287
 
 
 
 
 
 
 
 
 
 
 
1288/*
1289 * ext4_update_super() updates the super block so that the newly added
1290 * groups can be seen by the filesystem.
1291 *
1292 * @sb: super block
1293 * @flex_gd: new added groups
1294 */
1295static void ext4_update_super(struct super_block *sb,
1296			     struct ext4_new_flex_group_data *flex_gd)
1297{
1298	ext4_fsblk_t blocks_count = 0;
1299	ext4_fsblk_t free_blocks = 0;
1300	ext4_fsblk_t reserved_blocks = 0;
1301	struct ext4_new_group_data *group_data = flex_gd->groups;
1302	struct ext4_sb_info *sbi = EXT4_SB(sb);
1303	struct ext4_super_block *es = sbi->s_es;
1304	int i;
1305
1306	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1307	/*
1308	 * Make the new blocks and inodes valid next.  We do this before
1309	 * increasing the group count so that once the group is enabled,
1310	 * all of its blocks and inodes are already valid.
1311	 *
1312	 * We always allocate group-by-group, then block-by-block or
1313	 * inode-by-inode within a group, so enabling these
1314	 * blocks/inodes before the group is live won't actually let us
1315	 * allocate the new space yet.
1316	 */
1317	for (i = 0; i < flex_gd->count; i++) {
1318		blocks_count += group_data[i].blocks_count;
1319		free_blocks += group_data[i].free_blocks_count;
1320	}
1321
1322	reserved_blocks = ext4_r_blocks_count(es) * 100;
1323	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1324	reserved_blocks *= blocks_count;
1325	do_div(reserved_blocks, 100);
1326
 
1327	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1328	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1329	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1330		     flex_gd->count);
1331	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1332		     flex_gd->count);
1333
1334	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1335	/*
1336	 * We need to protect s_groups_count against other CPUs seeing
1337	 * inconsistent state in the superblock.
1338	 *
1339	 * The precise rules we use are:
1340	 *
1341	 * * Writers must perform a smp_wmb() after updating all
1342	 *   dependent data and before modifying the groups count
1343	 *
1344	 * * Readers must perform an smp_rmb() after reading the groups
1345	 *   count and before reading any dependent data.
1346	 *
1347	 * NB. These rules can be relaxed when checking the group count
1348	 * while freeing data, as we can only allocate from a block
1349	 * group after serialising against the group count, and we can
1350	 * only then free after serialising in turn against that
1351	 * allocation.
1352	 */
1353	smp_wmb();
1354
1355	/* Update the global fs size fields */
1356	sbi->s_groups_count += flex_gd->count;
1357	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1358			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1359
1360	/* Update the reserved block counts only once the new group is
1361	 * active. */
1362	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1363				reserved_blocks);
1364
1365	/* Update the free space counts */
1366	percpu_counter_add(&sbi->s_freeclusters_counter,
1367			   EXT4_NUM_B2C(sbi, free_blocks));
1368	percpu_counter_add(&sbi->s_freeinodes_counter,
1369			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1370
1371	ext4_debug("free blocks count %llu",
1372		   percpu_counter_read(&sbi->s_freeclusters_counter));
1373	if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1374				      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1375	    sbi->s_log_groups_per_flex) {
1376		ext4_group_t flex_group;
 
 
1377		flex_group = ext4_flex_group(sbi, group_data[0].group);
 
1378		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1379			     &sbi->s_flex_groups[flex_group].free_clusters);
1380		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1381			   &sbi->s_flex_groups[flex_group].free_inodes);
1382	}
1383
1384	/*
1385	 * Update the fs overhead information
 
 
 
 
1386	 */
1387	ext4_calculate_overhead(sb);
 
 
 
 
 
1388
 
 
1389	if (test_opt(sb, DEBUG))
1390		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1391		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1392		       blocks_count, free_blocks, reserved_blocks);
1393}
1394
1395/* Add a flex group to an fs. Ensure we handle all possible error conditions
1396 * _before_ we start modifying the filesystem, because we cannot abort the
1397 * transaction and not have it write the data to disk.
1398 */
1399static int ext4_flex_group_add(struct super_block *sb,
1400			       struct inode *resize_inode,
1401			       struct ext4_new_flex_group_data *flex_gd)
1402{
1403	struct ext4_sb_info *sbi = EXT4_SB(sb);
1404	struct ext4_super_block *es = sbi->s_es;
1405	ext4_fsblk_t o_blocks_count;
1406	ext4_grpblk_t last;
1407	ext4_group_t group;
1408	handle_t *handle;
1409	unsigned reserved_gdb;
1410	int err = 0, err2 = 0, credit;
1411
1412	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1413
1414	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1415	o_blocks_count = ext4_blocks_count(es);
1416	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1417	BUG_ON(last);
1418
1419	err = setup_new_flex_group_blocks(sb, flex_gd);
1420	if (err)
1421		goto exit;
1422	/*
1423	 * We will always be modifying at least the superblock and  GDT
1424	 * block.  If we are adding a group past the last current GDT block,
1425	 * we will also modify the inode and the dindirect block.  If we
1426	 * are adding a group with superblock/GDT backups  we will also
1427	 * modify each of the reserved GDT dindirect blocks.
1428	 */
1429	credit = flex_gd->count * 4 + reserved_gdb;
 
 
 
1430	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1431	if (IS_ERR(handle)) {
1432		err = PTR_ERR(handle);
1433		goto exit;
1434	}
1435
1436	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
 
 
1437	if (err)
1438		goto exit_journal;
1439
1440	group = flex_gd->groups[0].group;
1441	BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1442	err = ext4_add_new_descs(handle, sb, group,
1443				resize_inode, flex_gd->count);
1444	if (err)
1445		goto exit_journal;
1446
1447	err = ext4_setup_new_descs(handle, sb, flex_gd);
1448	if (err)
1449		goto exit_journal;
1450
1451	ext4_update_super(sb, flex_gd);
1452
1453	err = ext4_handle_dirty_super(handle, sb);
1454
1455exit_journal:
1456	err2 = ext4_journal_stop(handle);
1457	if (!err)
1458		err = err2;
1459
1460	if (!err) {
1461		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1462		int gdb_num_end = ((group + flex_gd->count - 1) /
1463				   EXT4_DESC_PER_BLOCK(sb));
1464		int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,
1465				EXT4_FEATURE_INCOMPAT_META_BG);
1466		sector_t old_gdb = 0;
 
1467
1468		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1469			       sizeof(struct ext4_super_block), 0);
1470		for (; gdb_num <= gdb_num_end; gdb_num++) {
1471			struct buffer_head *gdb_bh;
1472
1473			gdb_bh = sbi->s_group_desc[gdb_num];
1474			if (old_gdb == gdb_bh->b_blocknr)
1475				continue;
1476			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1477				       gdb_bh->b_size, meta_bg);
1478			old_gdb = gdb_bh->b_blocknr;
1479		}
1480	}
1481exit:
1482	return err;
1483}
1484
1485static int ext4_setup_next_flex_gd(struct super_block *sb,
1486				    struct ext4_new_flex_group_data *flex_gd,
1487				    ext4_fsblk_t n_blocks_count,
1488				    unsigned long flexbg_size)
1489{
1490	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 
1491	struct ext4_new_group_data *group_data = flex_gd->groups;
1492	ext4_fsblk_t o_blocks_count;
1493	ext4_group_t n_group;
1494	ext4_group_t group;
1495	ext4_group_t last_group;
1496	ext4_grpblk_t last;
1497	ext4_grpblk_t blocks_per_group;
1498	unsigned long i;
1499
1500	blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1501
1502	o_blocks_count = ext4_blocks_count(es);
1503
1504	if (o_blocks_count == n_blocks_count)
1505		return 0;
1506
1507	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1508	BUG_ON(last);
1509	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1510
1511	last_group = group | (flexbg_size - 1);
1512	if (last_group > n_group)
1513		last_group = n_group;
1514
1515	flex_gd->count = last_group - group + 1;
1516
1517	for (i = 0; i < flex_gd->count; i++) {
1518		int overhead;
1519
1520		group_data[i].group = group + i;
1521		group_data[i].blocks_count = blocks_per_group;
1522		overhead = ext4_group_overhead_blocks(sb, group + i);
1523		group_data[i].free_blocks_count = blocks_per_group - overhead;
 
1524		if (ext4_has_group_desc_csum(sb)) {
1525			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1526					       EXT4_BG_INODE_UNINIT;
1527			if (!test_opt(sb, INIT_INODE_TABLE))
1528				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1529		} else
1530			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1531	}
1532
1533	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1534		/* We need to initialize block bitmap of last group. */
1535		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1536
1537	if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1538		group_data[i - 1].blocks_count = last + 1;
1539		group_data[i - 1].free_blocks_count -= blocks_per_group-
1540					last - 1;
1541	}
1542
1543	return 1;
1544}
1545
1546/* Add group descriptor data to an existing or new group descriptor block.
1547 * Ensure we handle all possible error conditions _before_ we start modifying
1548 * the filesystem, because we cannot abort the transaction and not have it
1549 * write the data to disk.
1550 *
1551 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1552 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1553 *
1554 * We only need to hold the superblock lock while we are actually adding
1555 * in the new group's counts to the superblock.  Prior to that we have
1556 * not really "added" the group at all.  We re-check that we are still
1557 * adding in the last group in case things have changed since verifying.
1558 */
1559int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1560{
1561	struct ext4_new_flex_group_data flex_gd;
1562	struct ext4_sb_info *sbi = EXT4_SB(sb);
1563	struct ext4_super_block *es = sbi->s_es;
1564	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1565		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1566	struct inode *inode = NULL;
1567	int gdb_off;
1568	int err;
1569	__u16 bg_flags = 0;
1570
1571	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1572
1573	if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1574					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1575		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1576		return -EPERM;
1577	}
1578
1579	if (ext4_blocks_count(es) + input->blocks_count <
1580	    ext4_blocks_count(es)) {
1581		ext4_warning(sb, "blocks_count overflow");
1582		return -EINVAL;
1583	}
1584
1585	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1586	    le32_to_cpu(es->s_inodes_count)) {
1587		ext4_warning(sb, "inodes_count overflow");
1588		return -EINVAL;
1589	}
1590
1591	if (reserved_gdb || gdb_off == 0) {
1592		if (!EXT4_HAS_COMPAT_FEATURE(sb,
1593					     EXT4_FEATURE_COMPAT_RESIZE_INODE)
1594		    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1595			ext4_warning(sb,
1596				     "No reserved GDT blocks, can't resize");
1597			return -EPERM;
1598		}
1599		inode = ext4_iget(sb, EXT4_RESIZE_INO);
1600		if (IS_ERR(inode)) {
1601			ext4_warning(sb, "Error opening resize inode");
1602			return PTR_ERR(inode);
1603		}
1604	}
1605
1606
1607	err = verify_group_input(sb, input);
1608	if (err)
1609		goto out;
1610
1611	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1612	if (err)
1613		goto out;
1614
1615	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1616	if (err)
1617		goto out;
1618
1619	flex_gd.count = 1;
1620	flex_gd.groups = input;
1621	flex_gd.bg_flags = &bg_flags;
1622	err = ext4_flex_group_add(sb, inode, &flex_gd);
1623out:
1624	iput(inode);
1625	return err;
1626} /* ext4_group_add */
1627
1628/*
1629 * extend a group without checking assuming that checking has been done.
1630 */
1631static int ext4_group_extend_no_check(struct super_block *sb,
1632				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1633{
1634	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1635	handle_t *handle;
1636	int err = 0, err2;
1637
1638	/* We will update the superblock, one block bitmap, and
1639	 * one group descriptor via ext4_group_add_blocks().
1640	 */
1641	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1642	if (IS_ERR(handle)) {
1643		err = PTR_ERR(handle);
1644		ext4_warning(sb, "error %d on journal start", err);
1645		return err;
1646	}
1647
1648	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 
 
1649	if (err) {
1650		ext4_warning(sb, "error %d on journal write access", err);
1651		goto errout;
1652	}
1653
 
1654	ext4_blocks_count_set(es, o_blocks_count + add);
1655	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
 
 
1656	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1657		   o_blocks_count + add);
1658	/* We add the blocks to the bitmap and set the group need init bit */
1659	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1660	if (err)
1661		goto errout;
1662	ext4_handle_dirty_super(handle, sb);
1663	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1664		   o_blocks_count + add);
1665errout:
1666	err2 = ext4_journal_stop(handle);
1667	if (err2 && !err)
1668		err = err2;
1669
1670	if (!err) {
1671		if (test_opt(sb, DEBUG))
1672			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1673			       "blocks\n", ext4_blocks_count(es));
1674		update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1675			       (char *)es, sizeof(struct ext4_super_block), 0);
1676	}
1677	return err;
1678}
1679
1680/*
1681 * Extend the filesystem to the new number of blocks specified.  This entry
1682 * point is only used to extend the current filesystem to the end of the last
1683 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1684 * for emergencies (because it has no dependencies on reserved blocks).
1685 *
1686 * If we _really_ wanted, we could use default values to call ext4_group_add()
1687 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1688 * GDT blocks are reserved to grow to the desired size.
1689 */
1690int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1691		      ext4_fsblk_t n_blocks_count)
1692{
1693	ext4_fsblk_t o_blocks_count;
1694	ext4_grpblk_t last;
1695	ext4_grpblk_t add;
1696	struct buffer_head *bh;
1697	int err;
1698	ext4_group_t group;
1699
1700	o_blocks_count = ext4_blocks_count(es);
1701
1702	if (test_opt(sb, DEBUG))
1703		ext4_msg(sb, KERN_DEBUG,
1704			 "extending last group from %llu to %llu blocks",
1705			 o_blocks_count, n_blocks_count);
1706
1707	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1708		return 0;
1709
1710	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1711		ext4_msg(sb, KERN_ERR,
1712			 "filesystem too large to resize to %llu blocks safely",
1713			 n_blocks_count);
1714		if (sizeof(sector_t) < 8)
1715			ext4_warning(sb, "CONFIG_LBDAF not enabled");
1716		return -EINVAL;
1717	}
1718
1719	if (n_blocks_count < o_blocks_count) {
1720		ext4_warning(sb, "can't shrink FS - resize aborted");
1721		return -EINVAL;
1722	}
1723
1724	/* Handle the remaining blocks in the last group only. */
1725	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1726
1727	if (last == 0) {
1728		ext4_warning(sb, "need to use ext2online to resize further");
1729		return -EPERM;
1730	}
1731
1732	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1733
1734	if (o_blocks_count + add < o_blocks_count) {
1735		ext4_warning(sb, "blocks_count overflow");
1736		return -EINVAL;
1737	}
1738
1739	if (o_blocks_count + add > n_blocks_count)
1740		add = n_blocks_count - o_blocks_count;
1741
1742	if (o_blocks_count + add < n_blocks_count)
1743		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1744			     o_blocks_count + add, add);
1745
1746	/* See if the device is actually as big as what was requested */
1747	bh = sb_bread(sb, o_blocks_count + add - 1);
1748	if (!bh) {
1749		ext4_warning(sb, "can't read last block, resize aborted");
1750		return -ENOSPC;
1751	}
1752	brelse(bh);
1753
1754	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1755	return err;
1756} /* ext4_group_extend */
1757
1758
1759static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1760{
1761	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1762}
1763
1764/*
1765 * Release the resize inode and drop the resize_inode feature if there
1766 * are no more reserved gdt blocks, and then convert the file system
1767 * to enable meta_bg
1768 */
1769static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1770{
1771	handle_t *handle;
1772	struct ext4_sb_info *sbi = EXT4_SB(sb);
1773	struct ext4_super_block *es = sbi->s_es;
1774	struct ext4_inode_info *ei = EXT4_I(inode);
1775	ext4_fsblk_t nr;
1776	int i, ret, err = 0;
1777	int credits = 1;
1778
1779	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1780	if (inode) {
1781		if (es->s_reserved_gdt_blocks) {
1782			ext4_error(sb, "Unexpected non-zero "
1783				   "s_reserved_gdt_blocks");
1784			return -EPERM;
1785		}
1786
1787		/* Do a quick sanity check of the resize inode */
1788		if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
 
1789			goto invalid_resize_inode;
1790		for (i = 0; i < EXT4_N_BLOCKS; i++) {
1791			if (i == EXT4_DIND_BLOCK) {
1792				if (ei->i_data[i])
1793					continue;
1794				else
1795					goto invalid_resize_inode;
1796			}
1797			if (ei->i_data[i])
1798				goto invalid_resize_inode;
1799		}
1800		credits += 3;	/* block bitmap, bg descriptor, resize inode */
1801	}
1802
1803	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1804	if (IS_ERR(handle))
1805		return PTR_ERR(handle);
1806
1807	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
 
 
1808	if (err)
1809		goto errout;
1810
1811	EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
1812	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
 
1813	sbi->s_es->s_first_meta_bg =
1814		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
 
 
1815
1816	err = ext4_handle_dirty_super(handle, sb);
1817	if (err) {
1818		ext4_std_error(sb, err);
1819		goto errout;
1820	}
1821
1822	if (inode) {
1823		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1824		ext4_free_blocks(handle, inode, NULL, nr, 1,
1825				 EXT4_FREE_BLOCKS_METADATA |
1826				 EXT4_FREE_BLOCKS_FORGET);
1827		ei->i_data[EXT4_DIND_BLOCK] = 0;
1828		inode->i_blocks = 0;
1829
1830		err = ext4_mark_inode_dirty(handle, inode);
1831		if (err)
1832			ext4_std_error(sb, err);
1833	}
1834
1835errout:
1836	ret = ext4_journal_stop(handle);
1837	if (!err)
1838		err = ret;
1839	return ret;
1840
1841invalid_resize_inode:
1842	ext4_error(sb, "corrupted/inconsistent resize inode");
1843	return -EINVAL;
1844}
1845
1846/*
1847 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1848 *
1849 * @sb: super block of the fs to be resized
1850 * @n_blocks_count: the number of blocks resides in the resized fs
1851 */
1852int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1853{
1854	struct ext4_new_flex_group_data *flex_gd = NULL;
1855	struct ext4_sb_info *sbi = EXT4_SB(sb);
1856	struct ext4_super_block *es = sbi->s_es;
1857	struct buffer_head *bh;
1858	struct inode *resize_inode = NULL;
1859	ext4_grpblk_t add, offset;
1860	unsigned long n_desc_blocks;
1861	unsigned long o_desc_blocks;
1862	ext4_group_t o_group;
1863	ext4_group_t n_group;
1864	ext4_fsblk_t o_blocks_count;
1865	ext4_fsblk_t n_blocks_count_retry = 0;
1866	unsigned long last_update_time = 0;
1867	int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1868	int meta_bg;
 
1869
1870	/* See if the device is actually as big as what was requested */
1871	bh = sb_bread(sb, n_blocks_count - 1);
1872	if (!bh) {
1873		ext4_warning(sb, "can't read last block, resize aborted");
1874		return -ENOSPC;
1875	}
1876	brelse(bh);
1877
 
 
 
 
 
 
 
 
 
 
1878retry:
1879	o_blocks_count = ext4_blocks_count(es);
1880
1881	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1882		 "to %llu blocks", o_blocks_count, n_blocks_count);
1883
1884	if (n_blocks_count < o_blocks_count) {
1885		/* On-line shrinking not supported */
1886		ext4_warning(sb, "can't shrink FS - resize aborted");
1887		return -EINVAL;
1888	}
1889
1890	if (n_blocks_count == o_blocks_count)
1891		/* Nothing need to do */
1892		return 0;
1893
1894	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1895	if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1896		ext4_warning(sb, "resize would cause inodes_count overflow");
1897		return -EINVAL;
1898	}
1899	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1900
1901	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1902	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1903
1904	meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1905
1906	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
1907		if (meta_bg) {
1908			ext4_error(sb, "resize_inode and meta_bg enabled "
1909				   "simultaneously");
1910			return -EINVAL;
1911		}
1912		if (n_desc_blocks > o_desc_blocks +
1913		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
1914			n_blocks_count_retry = n_blocks_count;
1915			n_desc_blocks = o_desc_blocks +
1916				le16_to_cpu(es->s_reserved_gdt_blocks);
1917			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1918			n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
 
 
1919			n_group--; /* set to last group number */
1920		}
1921
1922		if (!resize_inode)
1923			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
 
1924		if (IS_ERR(resize_inode)) {
1925			ext4_warning(sb, "Error opening resize inode");
1926			return PTR_ERR(resize_inode);
1927		}
1928	}
1929
1930	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1931		err = ext4_convert_meta_bg(sb, resize_inode);
1932		if (err)
1933			goto out;
1934		if (resize_inode) {
1935			iput(resize_inode);
1936			resize_inode = NULL;
1937		}
1938		if (n_blocks_count_retry) {
1939			n_blocks_count = n_blocks_count_retry;
1940			n_blocks_count_retry = 0;
1941			goto retry;
1942		}
1943	}
1944
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1945	/* extend the last group */
1946	if (n_group == o_group)
1947		add = n_blocks_count - o_blocks_count;
1948	else
1949		add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1950	if (add > 0) {
1951		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1952		if (err)
1953			goto out;
1954	}
1955
1956	if (ext4_blocks_count(es) == n_blocks_count)
1957		goto out;
1958
1959	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1960	if (err)
1961		return err;
1962
1963	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1964	if (err)
1965		goto out;
1966
1967	flex_gd = alloc_flex_gd(flexbg_size);
1968	if (flex_gd == NULL) {
1969		err = -ENOMEM;
1970		goto out;
1971	}
1972
1973	/* Add flex groups. Note that a regular group is a
1974	 * flex group with 1 group.
1975	 */
1976	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1977					      flexbg_size)) {
1978		if (jiffies - last_update_time > HZ * 10) {
1979			if (last_update_time)
1980				ext4_msg(sb, KERN_INFO,
1981					 "resized to %llu blocks",
1982					 ext4_blocks_count(es));
1983			last_update_time = jiffies;
1984		}
1985		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1986			break;
1987		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1988		if (unlikely(err))
1989			break;
1990	}
1991
1992	if (!err && n_blocks_count_retry) {
1993		n_blocks_count = n_blocks_count_retry;
1994		n_blocks_count_retry = 0;
1995		free_flex_gd(flex_gd);
1996		flex_gd = NULL;
 
 
 
 
1997		goto retry;
1998	}
1999
2000out:
2001	if (flex_gd)
2002		free_flex_gd(flex_gd);
2003	if (resize_inode != NULL)
2004		iput(resize_inode);
2005	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
 
 
 
 
2006	return err;
2007}