fs/ext4/resize.c

   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
  19 int 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
  42 void ext4_resize_end(struct super_block *sb)
  43 {
  44         clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
  45         smp_mb__after_atomic();
  46 }
  47
  48 static 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
  54 static 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
  60 static 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
  73 static 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  */
 166 struct 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  */
 181 static 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
 204 out1:
 205         kfree(flex_gd->groups);
 206 out2:
 207         kfree(flex_gd);
 208 out3:
 209         return NULL;
 210 }
 211
 212 static 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  */
 232 static 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))));
 255 next_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
 342 static 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         BUFFER_TRACE(bh, "get_write_access");
 352         if ((err = ext4_journal_get_write_access(handle, bh))) {
 353                 brelse(bh);
 354                 bh = ERR_PTR(err);
 355         } else {
 356                 memset(bh->b_data, 0, sb->s_blocksize);
 357                 set_buffer_uptodate(bh);
 358         }
 359
 360         return bh;
 361 }
 362
 363 /*
 364  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 365  * If that fails, restart the transaction & regain write access for the
 366  * buffer head which is used for block_bitmap modifications.
 367  */
 368 static int extend_or_restart_transaction(handle_t *handle, int thresh)
 369 {
 370         int err;
 371
 372         if (ext4_handle_has_enough_credits(handle, thresh))
 373                 return 0;
 374
 375         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 376         if (err < 0)
 377                 return err;
 378         if (err) {
 379                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 380                 if (err)
 381                         return err;
 382         }
 383
 384         return 0;
 385 }
 386
 387 /*
 388  * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 389  *
 390  * Helper function for ext4_setup_new_group_blocks() which set .
 391  *
 392  * @sb: super block
 393  * @handle: journal handle
 394  * @flex_gd: flex group data
 395  */
 396 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 397                         struct ext4_new_flex_group_data *flex_gd,
 398                         ext4_fsblk_t block, ext4_group_t count)
 399 {
 400         ext4_group_t count2;
 401
 402         ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 403         for (count2 = count; count > 0; count -= count2, block += count2) {
 404                 ext4_fsblk_t start;
 405                 struct buffer_head *bh;
 406                 ext4_group_t group;
 407                 int err;
 408
 409                 group = ext4_get_group_number(sb, block);
 410                 start = ext4_group_first_block_no(sb, group);
 411                 group -= flex_gd->groups[0].group;
 412
 413                 count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
 414                 if (count2 > count)
 415                         count2 = count;
 416
 417                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 418                         BUG_ON(flex_gd->count > 1);
 419                         continue;
 420                 }
 421
 422                 err = extend_or_restart_transaction(handle, 1);
 423                 if (err)
 424                         return err;
 425
 426                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 427                 if (unlikely(!bh))
 428                         return -ENOMEM;
 429
 430                 BUFFER_TRACE(bh, "get_write_access");
 431                 err = ext4_journal_get_write_access(handle, bh);
 432                 if (err)
 433                         return err;
 434                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 435                            block - start, count2);
 436                 ext4_set_bits(bh->b_data, block - start, count2);
 437
 438                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 439                 if (unlikely(err))
 440                         return err;
 441                 brelse(bh);
 442         }
 443
 444         return 0;
 445 }
 446
 447 /*
 448  * Set up the block and inode bitmaps, and the inode table for the new groups.
 449  * This doesn't need to be part of the main transaction, since we are only
 450  * changing blocks outside the actual filesystem.  We still do journaling to
 451  * ensure the recovery is correct in case of a failure just after resize.
 452  * If any part of this fails, we simply abort the resize.
 453  *
 454  * setup_new_flex_group_blocks handles a flex group as follow:
 455  *  1. copy super block and GDT, and initialize group tables if necessary.
 456  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 457  *     super block and GDT.
 458  *  2. allocate group tables in block bitmaps, that is, set bits in block
 459  *     bitmap for blocks taken by group tables.
 460  */
 461 static int setup_new_flex_group_blocks(struct super_block *sb,
 462                                 struct ext4_new_flex_group_data *flex_gd)
 463 {
 464         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 465         ext4_fsblk_t start;
 466         ext4_fsblk_t block;
 467         struct ext4_sb_info *sbi = EXT4_SB(sb);
 468         struct ext4_super_block *es = sbi->s_es;
 469         struct ext4_new_group_data *group_data = flex_gd->groups;
 470         __u16 *bg_flags = flex_gd->bg_flags;
 471         handle_t *handle;
 472         ext4_group_t group, count;
 473         struct buffer_head *bh = NULL;
 474         int reserved_gdb, i, j, err = 0, err2;
 475         int meta_bg;
 476
 477         BUG_ON(!flex_gd->count || !group_data ||
 478                group_data[0].group != sbi->s_groups_count);
 479
 480         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 481         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
 482
 483         /* This transaction may be extended/restarted along the way */
 484         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 485         if (IS_ERR(handle))
 486                 return PTR_ERR(handle);
 487
 488         group = group_data[0].group;
 489         for (i = 0; i < flex_gd->count; i++, group++) {
 490                 unsigned long gdblocks;
 491                 ext4_grpblk_t overhead;
 492
 493                 gdblocks = ext4_bg_num_gdb(sb, group);
 494                 start = ext4_group_first_block_no(sb, group);
 495
 496                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 497                         goto handle_itb;
 498
 499                 if (meta_bg == 1) {
 500                         ext4_group_t first_group;
 501                         first_group = ext4_meta_bg_first_group(sb, group);
 502                         if (first_group != group + 1 &&
 503                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 504                                 goto handle_itb;
 505                 }
 506
 507                 block = start + ext4_bg_has_super(sb, group);
 508                 /* Copy all of the GDT blocks into the backup in this group */
 509                 for (j = 0; j < gdblocks; j++, block++) {
 510                         struct buffer_head *gdb;
 511
 512                         ext4_debug("update backup group %#04llx\n", block);
 513                         err = extend_or_restart_transaction(handle, 1);
 514                         if (err)
 515                                 goto out;
 516
 517                         gdb = sb_getblk(sb, block);
 518                         if (unlikely(!gdb)) {
 519                                 err = -ENOMEM;
 520                                 goto out;
 521                         }
 522
 523                         BUFFER_TRACE(gdb, "get_write_access");
 524                         err = ext4_journal_get_write_access(handle, gdb);
 525                         if (err) {
 526                                 brelse(gdb);
 527                                 goto out;
 528                         }
 529                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 530                                gdb->b_size);
 531                         set_buffer_uptodate(gdb);
 532
 533                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 534                         if (unlikely(err)) {
 535                                 brelse(gdb);
 536                                 goto out;
 537                         }
 538                         brelse(gdb);
 539                 }
 540
 541                 /* Zero out all of the reserved backup group descriptor
 542                  * table blocks
 543                  */
 544                 if (ext4_bg_has_super(sb, group)) {
 545                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 546                                         reserved_gdb, GFP_NOFS);
 547                         if (err)
 548                                 goto out;
 549                 }
 550
 551 handle_itb:
 552                 /* Initialize group tables of the grop @group */
 553                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 554                         goto handle_bb;
 555
 556                 /* Zero out all of the inode table blocks */
 557                 block = group_data[i].inode_table;
 558                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 559                            block, sbi->s_itb_per_group);
 560                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 561                                        GFP_NOFS);
 562                 if (err)
 563                         goto out;
 564
 565 handle_bb:
 566                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 567                         goto handle_ib;
 568
 569                 /* Initialize block bitmap of the @group */
 570                 block = group_data[i].block_bitmap;
 571                 err = extend_or_restart_transaction(handle, 1);
 572                 if (err)
 573                         goto out;
 574
 575                 bh = bclean(handle, sb, block);
 576                 if (IS_ERR(bh)) {
 577                         err = PTR_ERR(bh);
 578                         bh = NULL;
 579                         goto out;
 580                 }
 581                 overhead = ext4_group_overhead_blocks(sb, group);
 582                 if (overhead != 0) {
 583                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 584                                    start);
 585                         ext4_set_bits(bh->b_data, 0, overhead);
 586                 }
 587                 ext4_mark_bitmap_end(group_data[i].blocks_count,
 588                                      sb->s_blocksize * 8, bh->b_data);
 589                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 590                 if (err)
 591                         goto out;
 592                 brelse(bh);
 593
 594 handle_ib:
 595                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 596                         continue;
 597
 598                 /* Initialize inode bitmap of the @group */
 599                 block = group_data[i].inode_bitmap;
 600                 err = extend_or_restart_transaction(handle, 1);
 601                 if (err)
 602                         goto out;
 603                 /* Mark unused entries in inode bitmap used */
 604                 bh = bclean(handle, sb, block);
 605                 if (IS_ERR(bh)) {
 606                         err = PTR_ERR(bh);
 607                         bh = NULL;
 608                         goto out;
 609                 }
 610
 611                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 612                                      sb->s_blocksize * 8, bh->b_data);
 613                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 614                 if (err)
 615                         goto out;
 616                 brelse(bh);
 617         }
 618         bh = NULL;
 619
 620         /* Mark group tables in block bitmap */
 621         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 622                 count = group_table_count[j];
 623                 start = (&group_data[0].block_bitmap)[j];
 624                 block = start;
 625                 for (i = 1; i < flex_gd->count; i++) {
 626                         block += group_table_count[j];
 627                         if (block == (&group_data[i].block_bitmap)[j]) {
 628                                 count += group_table_count[j];
 629                                 continue;
 630                         }
 631                         err = set_flexbg_block_bitmap(sb, handle,
 632                                                 flex_gd, start, count);
 633                         if (err)
 634                                 goto out;
 635                         count = group_table_count[j];
 636                         start = (&group_data[i].block_bitmap)[j];
 637                         block = start;
 638                 }
 639
 640                 if (count) {
 641                         err = set_flexbg_block_bitmap(sb, handle,
 642                                                 flex_gd, start, count);
 643                         if (err)
 644                                 goto out;
 645                 }
 646         }
 647
 648 out:
 649         brelse(bh);
 650         err2 = ext4_journal_stop(handle);
 651         if (err2 && !err)
 652                 err = err2;
 653
 654         return err;
 655 }
 656
 657 /*
 658  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 659  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 660  * calling this for the first time.  In a sparse filesystem it will be the
 661  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 662  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 663  */
 664 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 665                                   unsigned *five, unsigned *seven)
 666 {
 667         unsigned *min = three;
 668         int mult = 3;
 669         unsigned ret;
 670
 671         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 672                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 673                 ret = *min;
 674                 *min += 1;
 675                 return ret;
 676         }
 677
 678         if (*five < *min) {
 679                 min = five;
 680                 mult = 5;
 681         }
 682         if (*seven < *min) {
 683                 min = seven;
 684                 mult = 7;
 685         }
 686
 687         ret = *min;
 688         *min *= mult;
 689
 690         return ret;
 691 }
 692
 693 /*
 694  * Check that all of the backup GDT blocks are held in the primary GDT block.
 695  * It is assumed that they are stored in group order.  Returns the number of
 696  * groups in current filesystem that have BACKUPS, or -ve error code.
 697  */
 698 static int verify_reserved_gdb(struct super_block *sb,
 699                                ext4_group_t end,
 700                                struct buffer_head *primary)
 701 {
 702         const ext4_fsblk_t blk = primary->b_blocknr;
 703         unsigned three = 1;
 704         unsigned five = 5;
 705         unsigned seven = 7;
 706         unsigned grp;
 707         __le32 *p = (__le32 *)primary->b_data;
 708         int gdbackups = 0;
 709
 710         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 711                 if (le32_to_cpu(*p++) !=
 712                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 713                         ext4_warning(sb, "reserved GDT %llu"
 714                                      " missing grp %d (%llu)",
 715                                      blk, grp,
 716                                      grp *
 717                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 718                                      blk);
 719                         return -EINVAL;
 720                 }
 721                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 722                         return -EFBIG;
 723         }
 724
 725         return gdbackups;
 726 }
 727
 728 /*
 729  * Called when we need to bring a reserved group descriptor table block into
 730  * use from the resize inode.  The primary copy of the new GDT block currently
 731  * is an indirect block (under the double indirect block in the resize inode).
 732  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 733  * block, in group order.  Even though we know all the block numbers we need,
 734  * we check to ensure that the resize inode has actually reserved these blocks.
 735  *
 736  * Don't need to update the block bitmaps because the blocks are still in use.
 737  *
 738  * We get all of the error cases out of the way, so that we are sure to not
 739  * fail once we start modifying the data on disk, because JBD has no rollback.
 740  */
 741 static int add_new_gdb(handle_t *handle, struct inode *inode,
 742                        ext4_group_t group)
 743 {
 744         struct super_block *sb = inode->i_sb;
 745         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 746         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 747         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 748         struct buffer_head **o_group_desc, **n_group_desc;
 749         struct buffer_head *dind;
 750         struct buffer_head *gdb_bh;
 751         int gdbackups;
 752         struct ext4_iloc iloc;
 753         __le32 *data;
 754         int err;
 755
 756         if (test_opt(sb, DEBUG))
 757                 printk(KERN_DEBUG
 758                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 759                        gdb_num);
 760
 761         /*
 762          * If we are not using the primary superblock/GDT copy don't resize,
 763          * because the user tools have no way of handling this.  Probably a
 764          * bad time to do it anyways.
 765          */
 766         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 767             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 768                 ext4_warning(sb, "won't resize using backup superblock at %llu",
 769                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 770                 return -EPERM;
 771         }
 772
 773         gdb_bh = sb_bread(sb, gdblock);
 774         if (!gdb_bh)
 775                 return -EIO;
 776
 777         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 778         if (gdbackups < 0) {
 779                 err = gdbackups;
 780                 goto exit_bh;
 781         }
 782
 783         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 784         dind = sb_bread(sb, le32_to_cpu(*data));
 785         if (!dind) {
 786                 err = -EIO;
 787                 goto exit_bh;
 788         }
 789
 790         data = (__le32 *)dind->b_data;
 791         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 792                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 793                              group, gdblock);
 794                 err = -EINVAL;
 795                 goto exit_dind;
 796         }
 797
 798         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 799         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 800         if (unlikely(err))
 801                 goto exit_dind;
 802
 803         BUFFER_TRACE(gdb_bh, "get_write_access");
 804         err = ext4_journal_get_write_access(handle, gdb_bh);
 805         if (unlikely(err))
 806                 goto exit_dind;
 807
 808         BUFFER_TRACE(dind, "get_write_access");
 809         err = ext4_journal_get_write_access(handle, dind);
 810         if (unlikely(err))
 811                 ext4_std_error(sb, err);
 812
 813         /* ext4_reserve_inode_write() gets a reference on the iloc */
 814         err = ext4_reserve_inode_write(handle, inode, &iloc);
 815         if (unlikely(err))
 816                 goto exit_dind;
 817
 818         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 819                                      sizeof(struct buffer_head *),
 820                                      GFP_NOFS);
 821         if (!n_group_desc) {
 822                 err = -ENOMEM;
 823                 ext4_warning(sb, "not enough memory for %lu groups",
 824                              gdb_num + 1);
 825                 goto exit_inode;
 826         }
 827
 828         /*
 829          * Finally, we have all of the possible failures behind us...
 830          *
 831          * Remove new GDT block from inode double-indirect block and clear out
 832          * the new GDT block for use (which also "frees" the backup GDT blocks
 833          * from the reserved inode).  We don't need to change the bitmaps for
 834          * these blocks, because they are marked as in-use from being in the
 835          * reserved inode, and will become GDT blocks (primary and backup).
 836          */
 837         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 838         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 839         if (unlikely(err)) {
 840                 ext4_std_error(sb, err);
 841                 goto exit_inode;
 842         }
 843         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 844         ext4_mark_iloc_dirty(handle, inode, &iloc);
 845         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 846         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 847         if (unlikely(err)) {
 848                 ext4_std_error(sb, err);
 849                 goto exit_inode;
 850         }
 851         brelse(dind);
 852
 853         o_group_desc = EXT4_SB(sb)->s_group_desc;
 854         memcpy(n_group_desc, o_group_desc,
 855                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 856         n_group_desc[gdb_num] = gdb_bh;
 857         EXT4_SB(sb)->s_group_desc = n_group_desc;
 858         EXT4_SB(sb)->s_gdb_count++;
 859         ext4_kvfree(o_group_desc);
 860
 861         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 862         err = ext4_handle_dirty_super(handle, sb);
 863         if (err)
 864                 ext4_std_error(sb, err);
 865
 866         return err;
 867
 868 exit_inode:
 869         ext4_kvfree(n_group_desc);
 870         brelse(iloc.bh);
 871 exit_dind:
 872         brelse(dind);
 873 exit_bh:
 874         brelse(gdb_bh);
 875
 876         ext4_debug("leaving with error %d\n", err);
 877         return err;
 878 }
 879
 880 /*
 881  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 882  */
 883 static int add_new_gdb_meta_bg(struct super_block *sb,
 884                                handle_t *handle, ext4_group_t group) {
 885         ext4_fsblk_t gdblock;
 886         struct buffer_head *gdb_bh;
 887         struct buffer_head **o_group_desc, **n_group_desc;
 888         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 889         int err;
 890
 891         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 892                    ext4_bg_has_super(sb, group);
 893         gdb_bh = sb_bread(sb, gdblock);
 894         if (!gdb_bh)
 895                 return -EIO;
 896         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 897                                      sizeof(struct buffer_head *),
 898                                      GFP_NOFS);
 899         if (!n_group_desc) {
 900                 err = -ENOMEM;
 901                 ext4_warning(sb, "not enough memory for %lu groups",
 902                              gdb_num + 1);
 903                 return err;
 904         }
 905
 906         o_group_desc = EXT4_SB(sb)->s_group_desc;
 907         memcpy(n_group_desc, o_group_desc,
 908                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 909         n_group_desc[gdb_num] = gdb_bh;
 910         EXT4_SB(sb)->s_group_desc = n_group_desc;
 911         EXT4_SB(sb)->s_gdb_count++;
 912         ext4_kvfree(o_group_desc);
 913         BUFFER_TRACE(gdb_bh, "get_write_access");
 914         err = ext4_journal_get_write_access(handle, gdb_bh);
 915         if (unlikely(err))
 916                 brelse(gdb_bh);
 917         return err;
 918 }
 919
 920 /*
 921  * Called when we are adding a new group which has a backup copy of each of
 922  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 923  * We need to add these reserved backup GDT blocks to the resize inode, so
 924  * that they are kept for future resizing and not allocated to files.
 925  *
 926  * Each reserved backup GDT block will go into a different indirect block.
 927  * The indirect blocks are actually the primary reserved GDT blocks,
 928  * so we know in advance what their block numbers are.  We only get the
 929  * double-indirect block to verify it is pointing to the primary reserved
 930  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 931  * backup GDT blocks are stored in their reserved primary GDT block.
 932  */
 933 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 934                               ext4_group_t group)
 935 {
 936         struct super_block *sb = inode->i_sb;
 937         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 938         struct buffer_head **primary;
 939         struct buffer_head *dind;
 940         struct ext4_iloc iloc;
 941         ext4_fsblk_t blk;
 942         __le32 *data, *end;
 943         int gdbackups = 0;
 944         int res, i;
 945         int err;
 946
 947         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 948         if (!primary)
 949                 return -ENOMEM;
 950
 951         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 952         dind = sb_bread(sb, le32_to_cpu(*data));
 953         if (!dind) {
 954                 err = -EIO;
 955                 goto exit_free;
 956         }
 957
 958         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 959         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 960                                          EXT4_ADDR_PER_BLOCK(sb));
 961         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 962
 963         /* Get each reserved primary GDT block and verify it holds backups */
 964         for (res = 0; res < reserved_gdb; res++, blk++) {
 965                 if (le32_to_cpu(*data) != blk) {
 966                         ext4_warning(sb, "reserved block %llu"
 967                                      " not at offset %ld",
 968                                      blk,
 969                                      (long)(data - (__le32 *)dind->b_data));
 970                         err = -EINVAL;
 971                         goto exit_bh;
 972                 }
 973                 primary[res] = sb_bread(sb, blk);
 974                 if (!primary[res]) {
 975                         err = -EIO;
 976                         goto exit_bh;
 977                 }
 978                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 979                 if (gdbackups < 0) {
 980                         brelse(primary[res]);
 981                         err = gdbackups;
 982                         goto exit_bh;
 983                 }
 984                 if (++data >= end)
 985                         data = (__le32 *)dind->b_data;
 986         }
 987
 988         for (i = 0; i < reserved_gdb; i++) {
 989                 BUFFER_TRACE(primary[i], "get_write_access");
 990                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
 991                         goto exit_bh;
 992         }
 993
 994         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 995                 goto exit_bh;
 996
 997         /*
 998          * Finally we can add each of the reserved backup GDT blocks from
 999          * the new group to its reserved primary GDT block.
1000          */
1001         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1002         for (i = 0; i < reserved_gdb; i++) {
1003                 int err2;
1004                 data = (__le32 *)primary[i]->b_data;
1005                 /* printk("reserving backup %lu[%u] = %lu\n",
1006                        primary[i]->b_blocknr, gdbackups,
1007                        blk + primary[i]->b_blocknr); */
1008                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1009                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1010                 if (!err)
1011                         err = err2;
1012         }
1013         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
1014         ext4_mark_iloc_dirty(handle, inode, &iloc);
1015
1016 exit_bh:
1017         while (--res >= 0)
1018                 brelse(primary[res]);
1019         brelse(dind);
1020
1021 exit_free:
1022         kfree(primary);
1023
1024         return err;
1025 }
1026
1027 /*
1028  * Update the backup copies of the ext4 metadata.  These don't need to be part
1029  * of the main resize transaction, because e2fsck will re-write them if there
1030  * is a problem (basically only OOM will cause a problem).  However, we
1031  * _should_ update the backups if possible, in case the primary gets trashed
1032  * for some reason and we need to run e2fsck from a backup superblock.  The
1033  * important part is that the new block and inode counts are in the backup
1034  * superblocks, and the location of the new group metadata in the GDT backups.
1035  *
1036  * We do not need take the s_resize_lock for this, because these
1037  * blocks are not otherwise touched by the filesystem code when it is
1038  * mounted.  We don't need to worry about last changing from
1039  * sbi->s_groups_count, because the worst that can happen is that we
1040  * do not copy the full number of backups at this time.  The resize
1041  * which changed s_groups_count will backup again.
1042  */
1043 static void update_backups(struct super_block *sb, int blk_off, char *data,
1044                            int size, int meta_bg)
1045 {
1046         struct ext4_sb_info *sbi = EXT4_SB(sb);
1047         ext4_group_t last;
1048         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1049         unsigned three = 1;
1050         unsigned five = 5;
1051         unsigned seven = 7;
1052         ext4_group_t group = 0;
1053         int rest = sb->s_blocksize - size;
1054         handle_t *handle;
1055         int err = 0, err2;
1056
1057         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1058         if (IS_ERR(handle)) {
1059                 group = 1;
1060                 err = PTR_ERR(handle);
1061                 goto exit_err;
1062         }
1063
1064         if (meta_bg == 0) {
1065                 group = ext4_list_backups(sb, &three, &five, &seven);
1066                 last = sbi->s_groups_count;
1067         } else {
1068                 group = ext4_meta_bg_first_group(sb, group) + 1;
1069                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1070         }
1071
1072         while (group < sbi->s_groups_count) {
1073                 struct buffer_head *bh;
1074                 ext4_fsblk_t backup_block;
1075
1076                 /* Out of journal space, and can't get more - abort - so sad */
1077                 if (ext4_handle_valid(handle) &&
1078                     handle->h_buffer_credits == 0 &&
1079                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1080                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1081                         break;
1082
1083                 if (meta_bg == 0)
1084                         backup_block = group * bpg + blk_off;
1085                 else
1086                         backup_block = (ext4_group_first_block_no(sb, group) +
1087                                         ext4_bg_has_super(sb, group));
1088
1089                 bh = sb_getblk(sb, backup_block);
1090                 if (unlikely(!bh)) {
1091                         err = -ENOMEM;
1092                         break;
1093                 }
1094                 ext4_debug("update metadata backup %llu(+%llu)\n",
1095                            backup_block, backup_block -
1096                            ext4_group_first_block_no(sb, group));
1097                 BUFFER_TRACE(bh, "get_write_access");
1098                 if ((err = ext4_journal_get_write_access(handle, bh)))
1099                         break;
1100                 lock_buffer(bh);
1101                 memcpy(bh->b_data, data, size);
1102                 if (rest)
1103                         memset(bh->b_data + size, 0, rest);
1104                 set_buffer_uptodate(bh);
1105                 unlock_buffer(bh);
1106                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1107                 if (unlikely(err))
1108                         ext4_std_error(sb, err);
1109                 brelse(bh);
1110
1111                 if (meta_bg == 0)
1112                         group = ext4_list_backups(sb, &three, &five, &seven);
1113                 else if (group == last)
1114                         break;
1115                 else
1116                         group = last;
1117         }
1118         if ((err2 = ext4_journal_stop(handle)) && !err)
1119                 err = err2;
1120
1121         /*
1122          * Ugh! Need to have e2fsck write the backup copies.  It is too
1123          * late to revert the resize, we shouldn't fail just because of
1124          * the backup copies (they are only needed in case of corruption).
1125          *
1126          * However, if we got here we have a journal problem too, so we
1127          * can't really start a transaction to mark the superblock.
1128          * Chicken out and just set the flag on the hope it will be written
1129          * to disk, and if not - we will simply wait until next fsck.
1130          */
1131 exit_err:
1132         if (err) {
1133                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1134                              "forcing fsck on next reboot", group, err);
1135                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1136                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1137                 mark_buffer_dirty(sbi->s_sbh);
1138         }
1139 }
1140
1141 /*
1142  * ext4_add_new_descs() adds @count group descriptor of groups
1143  * starting at @group
1144  *
1145  * @handle: journal handle
1146  * @sb: super block
1147  * @group: the group no. of the first group desc to be added
1148  * @resize_inode: the resize inode
1149  * @count: number of group descriptors to be added
1150  */
1151 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1152                               ext4_group_t group, struct inode *resize_inode,
1153                               ext4_group_t count)
1154 {
1155         struct ext4_sb_info *sbi = EXT4_SB(sb);
1156         struct ext4_super_block *es = sbi->s_es;
1157         struct buffer_head *gdb_bh;
1158         int i, gdb_off, gdb_num, err = 0;
1159         int meta_bg;
1160
1161         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1162         for (i = 0; i < count; i++, group++) {
1163                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1164                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1165
1166                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1167                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1168
1169                 /*
1170                  * We will only either add reserved group blocks to a backup group
1171                  * or remove reserved blocks for the first group in a new group block.
1172                  * Doing both would be mean more complex code, and sane people don't
1173                  * use non-sparse filesystems anymore.  This is already checked above.
1174                  */
1175                 if (gdb_off) {
1176                         gdb_bh = sbi->s_group_desc[gdb_num];
1177                         BUFFER_TRACE(gdb_bh, "get_write_access");
1178                         err = ext4_journal_get_write_access(handle, gdb_bh);
1179
1180                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1181                                 err = reserve_backup_gdb(handle, resize_inode, group);
1182                 } else if (meta_bg != 0) {
1183                         err = add_new_gdb_meta_bg(sb, handle, group);
1184                 } else {
1185                         err = add_new_gdb(handle, resize_inode, group);
1186                 }
1187                 if (err)
1188                         break;
1189         }
1190         return err;
1191 }
1192
1193 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1194 {
1195         struct buffer_head *bh = sb_getblk(sb, block);
1196         if (unlikely(!bh))
1197                 return NULL;
1198         if (!bh_uptodate_or_lock(bh)) {
1199                 if (bh_submit_read(bh) < 0) {
1200                         brelse(bh);
1201                         return NULL;
1202                 }
1203         }
1204
1205         return bh;
1206 }
1207
1208 static int ext4_set_bitmap_checksums(struct super_block *sb,
1209                                      ext4_group_t group,
1210                                      struct ext4_group_desc *gdp,
1211                                      struct ext4_new_group_data *group_data)
1212 {
1213         struct buffer_head *bh;
1214
1215         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1216                                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1217                 return 0;
1218
1219         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1220         if (!bh)
1221                 return -EIO;
1222         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1223                                    EXT4_INODES_PER_GROUP(sb) / 8);
1224         brelse(bh);
1225
1226         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1227         if (!bh)
1228                 return -EIO;
1229         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1230         brelse(bh);
1231
1232         return 0;
1233 }
1234
1235 /*
1236  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1237  */
1238 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1239                                 struct ext4_new_flex_group_data *flex_gd)
1240 {
1241         struct ext4_new_group_data      *group_data = flex_gd->groups;
1242         struct ext4_group_desc          *gdp;
1243         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1244         struct buffer_head              *gdb_bh;
1245         ext4_group_t                    group;
1246         __u16                           *bg_flags = flex_gd->bg_flags;
1247         int                             i, gdb_off, gdb_num, err = 0;
1248
1249
1250         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1251                 group = group_data->group;
1252
1253                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1254                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1255
1256                 /*
1257                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1258                  */
1259                 gdb_bh = sbi->s_group_desc[gdb_num];
1260                 /* Update group descriptor block for new group */
1261                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1262                                                  gdb_off * EXT4_DESC_SIZE(sb));
1263
1264                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1265                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1266                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1267                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1268                 if (err) {
1269                         ext4_std_error(sb, err);
1270                         break;
1271                 }
1272
1273                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1274                 ext4_free_group_clusters_set(sb, gdp,
1275                         EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1276                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1277                 if (ext4_has_group_desc_csum(sb))
1278                         ext4_itable_unused_set(sb, gdp,
1279                                                EXT4_INODES_PER_GROUP(sb));
1280                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1281                 ext4_group_desc_csum_set(sb, group, gdp);
1282
1283                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1284                 if (unlikely(err)) {
1285                         ext4_std_error(sb, err);
1286                         break;
1287                 }
1288
1289                 /*
1290                  * We can allocate memory for mb_alloc based on the new group
1291                  * descriptor
1292                  */
1293                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1294                 if (err)
1295                         break;
1296         }
1297         return err;
1298 }
1299
1300 /*
1301  * ext4_update_super() updates the super block so that the newly added
1302  * groups can be seen by the filesystem.
1303  *
1304  * @sb: super block
1305  * @flex_gd: new added groups
1306  */
1307 static void ext4_update_super(struct super_block *sb,
1308                              struct ext4_new_flex_group_data *flex_gd)
1309 {
1310         ext4_fsblk_t blocks_count = 0;
1311         ext4_fsblk_t free_blocks = 0;
1312         ext4_fsblk_t reserved_blocks = 0;
1313         struct ext4_new_group_data *group_data = flex_gd->groups;
1314         struct ext4_sb_info *sbi = EXT4_SB(sb);
1315         struct ext4_super_block *es = sbi->s_es;
1316         int i;
1317
1318         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1319         /*
1320          * Make the new blocks and inodes valid next.  We do this before
1321          * increasing the group count so that once the group is enabled,
1322          * all of its blocks and inodes are already valid.
1323          *
1324          * We always allocate group-by-group, then block-by-block or
1325          * inode-by-inode within a group, so enabling these
1326          * blocks/inodes before the group is live won't actually let us
1327          * allocate the new space yet.
1328          */
1329         for (i = 0; i < flex_gd->count; i++) {
1330                 blocks_count += group_data[i].blocks_count;
1331                 free_blocks += group_data[i].free_blocks_count;
1332         }
1333
1334         reserved_blocks = ext4_r_blocks_count(es) * 100;
1335         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1336         reserved_blocks *= blocks_count;
1337         do_div(reserved_blocks, 100);
1338
1339         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1340         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1341         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1342                      flex_gd->count);
1343         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1344                      flex_gd->count);
1345
1346         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1347         /*
1348          * We need to protect s_groups_count against other CPUs seeing
1349          * inconsistent state in the superblock.
1350          *
1351          * The precise rules we use are:
1352          *
1353          * * Writers must perform a smp_wmb() after updating all
1354          *   dependent data and before modifying the groups count
1355          *
1356          * * Readers must perform an smp_rmb() after reading the groups
1357          *   count and before reading any dependent data.
1358          *
1359          * NB. These rules can be relaxed when checking the group count
1360          * while freeing data, as we can only allocate from a block
1361          * group after serialising against the group count, and we can
1362          * only then free after serialising in turn against that
1363          * allocation.
1364          */
1365         smp_wmb();
1366
1367         /* Update the global fs size fields */
1368         sbi->s_groups_count += flex_gd->count;
1369         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1370                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1371
1372         /* Update the reserved block counts only once the new group is
1373          * active. */
1374         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1375                                 reserved_blocks);
1376
1377         /* Update the free space counts */
1378         percpu_counter_add(&sbi->s_freeclusters_counter,
1379                            EXT4_NUM_B2C(sbi, free_blocks));
1380         percpu_counter_add(&sbi->s_freeinodes_counter,
1381                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1382
1383         ext4_debug("free blocks count %llu",
1384                    percpu_counter_read(&sbi->s_freeclusters_counter));
1385         if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1386                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1387             sbi->s_log_groups_per_flex) {
1388                 ext4_group_t flex_group;
1389                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1390                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1391                              &sbi->s_flex_groups[flex_group].free_clusters);
1392                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1393                            &sbi->s_flex_groups[flex_group].free_inodes);
1394         }
1395
1396         /*
1397          * Update the fs overhead information
1398          */
1399         ext4_calculate_overhead(sb);
1400
1401         if (test_opt(sb, DEBUG))
1402                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1403                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1404                        blocks_count, free_blocks, reserved_blocks);
1405 }
1406
1407 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1408  * _before_ we start modifying the filesystem, because we cannot abort the
1409  * transaction and not have it write the data to disk.
1410  */
1411 static int ext4_flex_group_add(struct super_block *sb,
1412                                struct inode *resize_inode,
1413                                struct ext4_new_flex_group_data *flex_gd)
1414 {
1415         struct ext4_sb_info *sbi = EXT4_SB(sb);
1416         struct ext4_super_block *es = sbi->s_es;
1417         ext4_fsblk_t o_blocks_count;
1418         ext4_grpblk_t last;
1419         ext4_group_t group;
1420         handle_t *handle;
1421         unsigned reserved_gdb;
1422         int err = 0, err2 = 0, credit;
1423
1424         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1425
1426         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1427         o_blocks_count = ext4_blocks_count(es);
1428         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1429         BUG_ON(last);
1430
1431         err = setup_new_flex_group_blocks(sb, flex_gd);
1432         if (err)
1433                 goto exit;
1434         /*
1435          * We will always be modifying at least the superblock and  GDT
1436          * block.  If we are adding a group past the last current GDT block,
1437          * we will also modify the inode and the dindirect block.  If we
1438          * are adding a group with superblock/GDT backups  we will also
1439          * modify each of the reserved GDT dindirect blocks.
1440          */
1441         credit = flex_gd->count * 4 + reserved_gdb;
1442         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1443         if (IS_ERR(handle)) {
1444                 err = PTR_ERR(handle);
1445                 goto exit;
1446         }
1447
1448         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1449         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1450         if (err)
1451                 goto exit_journal;
1452
1453         group = flex_gd->groups[0].group;
1454         BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1455         err = ext4_add_new_descs(handle, sb, group,
1456                                 resize_inode, flex_gd->count);
1457         if (err)
1458                 goto exit_journal;
1459
1460         err = ext4_setup_new_descs(handle, sb, flex_gd);
1461         if (err)
1462                 goto exit_journal;
1463
1464         ext4_update_super(sb, flex_gd);
1465
1466         err = ext4_handle_dirty_super(handle, sb);
1467
1468 exit_journal:
1469         err2 = ext4_journal_stop(handle);
1470         if (!err)
1471                 err = err2;
1472
1473         if (!err) {
1474                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1475                 int gdb_num_end = ((group + flex_gd->count - 1) /
1476                                    EXT4_DESC_PER_BLOCK(sb));
1477                 int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,
1478                                 EXT4_FEATURE_INCOMPAT_META_BG);
1479                 sector_t old_gdb = 0;
1480
1481                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1482                                sizeof(struct ext4_super_block), 0);
1483                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1484                         struct buffer_head *gdb_bh;
1485
1486                         gdb_bh = sbi->s_group_desc[gdb_num];
1487                         if (old_gdb == gdb_bh->b_blocknr)
1488                                 continue;
1489                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1490                                        gdb_bh->b_size, meta_bg);
1491                         old_gdb = gdb_bh->b_blocknr;
1492                 }
1493         }
1494 exit:
1495         return err;
1496 }
1497
1498 static int ext4_setup_next_flex_gd(struct super_block *sb,
1499                                     struct ext4_new_flex_group_data *flex_gd,
1500                                     ext4_fsblk_t n_blocks_count,
1501                                     unsigned long flexbg_size)
1502 {
1503         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1504         struct ext4_new_group_data *group_data = flex_gd->groups;
1505         ext4_fsblk_t o_blocks_count;
1506         ext4_group_t n_group;
1507         ext4_group_t group;
1508         ext4_group_t last_group;
1509         ext4_grpblk_t last;
1510         ext4_grpblk_t blocks_per_group;
1511         unsigned long i;
1512
1513         blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1514
1515         o_blocks_count = ext4_blocks_count(es);
1516
1517         if (o_blocks_count == n_blocks_count)
1518                 return 0;
1519
1520         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1521         BUG_ON(last);
1522         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1523
1524         last_group = group | (flexbg_size - 1);
1525         if (last_group > n_group)
1526                 last_group = n_group;
1527
1528         flex_gd->count = last_group - group + 1;
1529
1530         for (i = 0; i < flex_gd->count; i++) {
1531                 int overhead;
1532
1533                 group_data[i].group = group + i;
1534                 group_data[i].blocks_count = blocks_per_group;
1535                 overhead = ext4_group_overhead_blocks(sb, group + i);
1536                 group_data[i].free_blocks_count = blocks_per_group - overhead;
1537                 if (ext4_has_group_desc_csum(sb)) {
1538                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1539                                                EXT4_BG_INODE_UNINIT;
1540                         if (!test_opt(sb, INIT_INODE_TABLE))
1541                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1542                 } else
1543                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1544         }
1545
1546         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1547                 /* We need to initialize block bitmap of last group. */
1548                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1549
1550         if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1551                 group_data[i - 1].blocks_count = last + 1;
1552                 group_data[i - 1].free_blocks_count -= blocks_per_group-
1553                                         last - 1;
1554         }
1555
1556         return 1;
1557 }
1558
1559 /* Add group descriptor data to an existing or new group descriptor block.
1560  * Ensure we handle all possible error conditions _before_ we start modifying
1561  * the filesystem, because we cannot abort the transaction and not have it
1562  * write the data to disk.
1563  *
1564  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1565  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1566  *
1567  * We only need to hold the superblock lock while we are actually adding
1568  * in the new group's counts to the superblock.  Prior to that we have
1569  * not really "added" the group at all.  We re-check that we are still
1570  * adding in the last group in case things have changed since verifying.
1571  */
1572 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1573 {
1574         struct ext4_new_flex_group_data flex_gd;
1575         struct ext4_sb_info *sbi = EXT4_SB(sb);
1576         struct ext4_super_block *es = sbi->s_es;
1577         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1578                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1579         struct inode *inode = NULL;
1580         int gdb_off;
1581         int err;
1582         __u16 bg_flags = 0;
1583
1584         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1585
1586         if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1587                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1588                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1589                 return -EPERM;
1590         }
1591
1592         if (ext4_blocks_count(es) + input->blocks_count <
1593             ext4_blocks_count(es)) {
1594                 ext4_warning(sb, "blocks_count overflow");
1595                 return -EINVAL;
1596         }
1597
1598         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1599             le32_to_cpu(es->s_inodes_count)) {
1600                 ext4_warning(sb, "inodes_count overflow");
1601                 return -EINVAL;
1602         }
1603
1604         if (reserved_gdb || gdb_off == 0) {
1605                 if (!EXT4_HAS_COMPAT_FEATURE(sb,
1606                                              EXT4_FEATURE_COMPAT_RESIZE_INODE)
1607                     || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1608                         ext4_warning(sb,
1609                                      "No reserved GDT blocks, can't resize");
1610                         return -EPERM;
1611                 }
1612                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1613                 if (IS_ERR(inode)) {
1614                         ext4_warning(sb, "Error opening resize inode");
1615                         return PTR_ERR(inode);
1616                 }
1617         }
1618
1619
1620         err = verify_group_input(sb, input);
1621         if (err)
1622                 goto out;
1623
1624         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1625         if (err)
1626                 goto out;
1627
1628         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1629         if (err)
1630                 goto out;
1631
1632         flex_gd.count = 1;
1633         flex_gd.groups = input;
1634         flex_gd.bg_flags = &bg_flags;
1635         err = ext4_flex_group_add(sb, inode, &flex_gd);
1636 out:
1637         iput(inode);
1638         return err;
1639 } /* ext4_group_add */
1640
1641 /*
1642  * extend a group without checking assuming that checking has been done.
1643  */
1644 static int ext4_group_extend_no_check(struct super_block *sb,
1645                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1646 {
1647         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1648         handle_t *handle;
1649         int err = 0, err2;
1650
1651         /* We will update the superblock, one block bitmap, and
1652          * one group descriptor via ext4_group_add_blocks().
1653          */
1654         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1655         if (IS_ERR(handle)) {
1656                 err = PTR_ERR(handle);
1657                 ext4_warning(sb, "error %d on journal start", err);
1658                 return err;
1659         }
1660
1661         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1662         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1663         if (err) {
1664                 ext4_warning(sb, "error %d on journal write access", err);
1665                 goto errout;
1666         }
1667
1668         ext4_blocks_count_set(es, o_blocks_count + add);
1669         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1670         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1671                    o_blocks_count + add);
1672         /* We add the blocks to the bitmap and set the group need init bit */
1673         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1674         if (err)
1675                 goto errout;
1676         ext4_handle_dirty_super(handle, sb);
1677         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1678                    o_blocks_count + add);
1679 errout:
1680         err2 = ext4_journal_stop(handle);
1681         if (err2 && !err)
1682                 err = err2;
1683
1684         if (!err) {
1685                 if (test_opt(sb, DEBUG))
1686                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1687                                "blocks\n", ext4_blocks_count(es));
1688                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1689                                (char *)es, sizeof(struct ext4_super_block), 0);
1690         }
1691         return err;
1692 }
1693
1694 /*
1695  * Extend the filesystem to the new number of blocks specified.  This entry
1696  * point is only used to extend the current filesystem to the end of the last
1697  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1698  * for emergencies (because it has no dependencies on reserved blocks).
1699  *
1700  * If we _really_ wanted, we could use default values to call ext4_group_add()
1701  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1702  * GDT blocks are reserved to grow to the desired size.
1703  */
1704 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1705                       ext4_fsblk_t n_blocks_count)
1706 {
1707         ext4_fsblk_t o_blocks_count;
1708         ext4_grpblk_t last;
1709         ext4_grpblk_t add;
1710         struct buffer_head *bh;
1711         int err;
1712         ext4_group_t group;
1713
1714         o_blocks_count = ext4_blocks_count(es);
1715
1716         if (test_opt(sb, DEBUG))
1717                 ext4_msg(sb, KERN_DEBUG,
1718                          "extending last group from %llu to %llu blocks",
1719                          o_blocks_count, n_blocks_count);
1720
1721         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1722                 return 0;
1723
1724         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1725                 ext4_msg(sb, KERN_ERR,
1726                          "filesystem too large to resize to %llu blocks safely",
1727                          n_blocks_count);
1728                 if (sizeof(sector_t) < 8)
1729                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1730                 return -EINVAL;
1731         }
1732
1733         if (n_blocks_count < o_blocks_count) {
1734                 ext4_warning(sb, "can't shrink FS - resize aborted");
1735                 return -EINVAL;
1736         }
1737
1738         /* Handle the remaining blocks in the last group only. */
1739         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1740
1741         if (last == 0) {
1742                 ext4_warning(sb, "need to use ext2online to resize further");
1743                 return -EPERM;
1744         }
1745
1746         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1747
1748         if (o_blocks_count + add < o_blocks_count) {
1749                 ext4_warning(sb, "blocks_count overflow");
1750                 return -EINVAL;
1751         }
1752
1753         if (o_blocks_count + add > n_blocks_count)
1754                 add = n_blocks_count - o_blocks_count;
1755
1756         if (o_blocks_count + add < n_blocks_count)
1757                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1758                              o_blocks_count + add, add);
1759
1760         /* See if the device is actually as big as what was requested */
1761         bh = sb_bread(sb, o_blocks_count + add - 1);
1762         if (!bh) {
1763                 ext4_warning(sb, "can't read last block, resize aborted");
1764                 return -ENOSPC;
1765         }
1766         brelse(bh);
1767
1768         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1769         return err;
1770 } /* ext4_group_extend */
1771
1772
1773 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1774 {
1775         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1776 }
1777
1778 /*
1779  * Release the resize inode and drop the resize_inode feature if there
1780  * are no more reserved gdt blocks, and then convert the file system
1781  * to enable meta_bg
1782  */
1783 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1784 {
1785         handle_t *handle;
1786         struct ext4_sb_info *sbi = EXT4_SB(sb);
1787         struct ext4_super_block *es = sbi->s_es;
1788         struct ext4_inode_info *ei = EXT4_I(inode);
1789         ext4_fsblk_t nr;
1790         int i, ret, err = 0;
1791         int credits = 1;
1792
1793         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1794         if (inode) {
1795                 if (es->s_reserved_gdt_blocks) {
1796                         ext4_error(sb, "Unexpected non-zero "
1797                                    "s_reserved_gdt_blocks");
1798                         return -EPERM;
1799                 }
1800
1801                 /* Do a quick sanity check of the resize inode */
1802                 if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
1803                         goto invalid_resize_inode;
1804                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1805                         if (i == EXT4_DIND_BLOCK) {
1806                                 if (ei->i_data[i])
1807                                         continue;
1808                                 else
1809                                         goto invalid_resize_inode;
1810                         }
1811                         if (ei->i_data[i])
1812                                 goto invalid_resize_inode;
1813                 }
1814                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1815         }
1816
1817         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1818         if (IS_ERR(handle))
1819                 return PTR_ERR(handle);
1820
1821         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1822         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1823         if (err)
1824                 goto errout;
1825
1826         EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
1827         EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1828         sbi->s_es->s_first_meta_bg =
1829                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1830
1831         err = ext4_handle_dirty_super(handle, sb);
1832         if (err) {
1833                 ext4_std_error(sb, err);
1834                 goto errout;
1835         }
1836
1837         if (inode) {
1838                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1839                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1840                                  EXT4_FREE_BLOCKS_METADATA |
1841                                  EXT4_FREE_BLOCKS_FORGET);
1842                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1843                 inode->i_blocks = 0;
1844
1845                 err = ext4_mark_inode_dirty(handle, inode);
1846                 if (err)
1847                         ext4_std_error(sb, err);
1848         }
1849
1850 errout:
1851         ret = ext4_journal_stop(handle);
1852         if (!err)
1853                 err = ret;
1854         return ret;
1855
1856 invalid_resize_inode:
1857         ext4_error(sb, "corrupted/inconsistent resize inode");
1858         return -EINVAL;
1859 }
1860
1861 /*
1862  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1863  *
1864  * @sb: super block of the fs to be resized
1865  * @n_blocks_count: the number of blocks resides in the resized fs
1866  */
1867 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1868 {
1869         struct ext4_new_flex_group_data *flex_gd = NULL;
1870         struct ext4_sb_info *sbi = EXT4_SB(sb);
1871         struct ext4_super_block *es = sbi->s_es;
1872         struct buffer_head *bh;
1873         struct inode *resize_inode = NULL;
1874         ext4_grpblk_t add, offset;
1875         unsigned long n_desc_blocks;
1876         unsigned long o_desc_blocks;
1877         ext4_group_t o_group;
1878         ext4_group_t n_group;
1879         ext4_fsblk_t o_blocks_count;
1880         ext4_fsblk_t n_blocks_count_retry = 0;
1881         unsigned long last_update_time = 0;
1882         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1883         int meta_bg;
1884
1885         /* See if the device is actually as big as what was requested */
1886         bh = sb_bread(sb, n_blocks_count - 1);
1887         if (!bh) {
1888                 ext4_warning(sb, "can't read last block, resize aborted");
1889                 return -ENOSPC;
1890         }
1891         brelse(bh);
1892
1893 retry:
1894         o_blocks_count = ext4_blocks_count(es);
1895
1896         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1897                  "to %llu blocks", o_blocks_count, n_blocks_count);
1898
1899         if (n_blocks_count < o_blocks_count) {
1900                 /* On-line shrinking not supported */
1901                 ext4_warning(sb, "can't shrink FS - resize aborted");
1902                 return -EINVAL;
1903         }
1904
1905         if (n_blocks_count == o_blocks_count)
1906                 /* Nothing need to do */
1907                 return 0;
1908
1909         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1910         if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1911                 ext4_warning(sb, "resize would cause inodes_count overflow");
1912                 return -EINVAL;
1913         }
1914         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1915
1916         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1917         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1918
1919         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1920
1921         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
1922                 if (meta_bg) {
1923                         ext4_error(sb, "resize_inode and meta_bg enabled "
1924                                    "simultaneously");
1925                         return -EINVAL;
1926                 }
1927                 if (n_desc_blocks > o_desc_blocks +
1928                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1929                         n_blocks_count_retry = n_blocks_count;
1930                         n_desc_blocks = o_desc_blocks +
1931                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1932                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1933                         n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
1934                         n_group--; /* set to last group number */
1935                 }
1936
1937                 if (!resize_inode)
1938                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1939                 if (IS_ERR(resize_inode)) {
1940                         ext4_warning(sb, "Error opening resize inode");
1941                         return PTR_ERR(resize_inode);
1942                 }
1943         }
1944
1945         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1946                 err = ext4_convert_meta_bg(sb, resize_inode);
1947                 if (err)
1948                         goto out;
1949                 if (resize_inode) {
1950                         iput(resize_inode);
1951                         resize_inode = NULL;
1952                 }
1953                 if (n_blocks_count_retry) {
1954                         n_blocks_count = n_blocks_count_retry;
1955                         n_blocks_count_retry = 0;
1956                         goto retry;
1957                 }
1958         }
1959
1960         /* extend the last group */
1961         if (n_group == o_group)
1962                 add = n_blocks_count - o_blocks_count;
1963         else
1964                 add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1965         if (add > 0) {
1966                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1967                 if (err)
1968                         goto out;
1969         }
1970
1971         if (ext4_blocks_count(es) == n_blocks_count)
1972                 goto out;
1973
1974         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1975         if (err)
1976                 return err;
1977
1978         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1979         if (err)
1980                 goto out;
1981
1982         flex_gd = alloc_flex_gd(flexbg_size);
1983         if (flex_gd == NULL) {
1984                 err = -ENOMEM;
1985                 goto out;
1986         }
1987
1988         /* Add flex groups. Note that a regular group is a
1989          * flex group with 1 group.
1990          */
1991         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1992                                               flexbg_size)) {
1993                 if (jiffies - last_update_time > HZ * 10) {
1994                         if (last_update_time)
1995                                 ext4_msg(sb, KERN_INFO,
1996                                          "resized to %llu blocks",
1997                                          ext4_blocks_count(es));
1998                         last_update_time = jiffies;
1999                 }
2000                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2001                         break;
2002                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2003                 if (unlikely(err))
2004                         break;
2005         }
2006
2007         if (!err && n_blocks_count_retry) {
2008                 n_blocks_count = n_blocks_count_retry;
2009                 n_blocks_count_retry = 0;
2010                 free_flex_gd(flex_gd);
2011                 flex_gd = NULL;
2012                 goto retry;
2013         }
2014
2015 out:
2016         if (flex_gd)
2017                 free_flex_gd(flex_gd);
2018         if (resize_inode != NULL)
2019                 iput(resize_inode);
2020         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2021         return err;
2022 }