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          * If we are not using the primary superblock/GDT copy don't resize,
  28          * because the user tools have no way of handling this.  Probably a
  29          * bad time to do it anyways.
  30          */
  31         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
  32             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  33                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  34                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  35                 return -EPERM;
  36         }
  37
  38         /*
  39          * We are not allowed to do online-resizing on a filesystem mounted
  40          * with error, because it can destroy the filesystem easily.
  41          */
  42         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  43                 ext4_warning(sb, "There are errors in the filesystem, "
  44                              "so online resizing is not allowed");
  45                 return -EPERM;
  46         }
  47
  48         if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
  49                 ret = -EBUSY;
  50
  51         return ret;
  52 }
  53
  54 void ext4_resize_end(struct super_block *sb)
  55 {
  56         clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
  57         smp_mb__after_atomic();
  58 }
  59
  60 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  61                                              ext4_group_t group) {
  62         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  63                EXT4_DESC_PER_BLOCK_BITS(sb);
  64 }
  65
  66 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  67                                              ext4_group_t group) {
  68         group = ext4_meta_bg_first_group(sb, group);
  69         return ext4_group_first_block_no(sb, group);
  70 }
  71
  72 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  73                                                 ext4_group_t group) {
  74         ext4_grpblk_t overhead;
  75         overhead = ext4_bg_num_gdb(sb, group);
  76         if (ext4_bg_has_super(sb, group))
  77                 overhead += 1 +
  78                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  79         return overhead;
  80 }
  81
  82 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
  83 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  84
  85 static int verify_group_input(struct super_block *sb,
  86                               struct ext4_new_group_data *input)
  87 {
  88         struct ext4_sb_info *sbi = EXT4_SB(sb);
  89         struct ext4_super_block *es = sbi->s_es;
  90         ext4_fsblk_t start = ext4_blocks_count(es);
  91         ext4_fsblk_t end = start + input->blocks_count;
  92         ext4_group_t group = input->group;
  93         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  94         unsigned overhead;
  95         ext4_fsblk_t metaend;
  96         struct buffer_head *bh = NULL;
  97         ext4_grpblk_t free_blocks_count, offset;
  98         int err = -EINVAL;
  99
 100         if (group != sbi->s_groups_count) {
 101                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 102                              input->group, sbi->s_groups_count);
 103                 return -EINVAL;
 104         }
 105
 106         overhead = ext4_group_overhead_blocks(sb, group);
 107         metaend = start + overhead;
 108         input->free_blocks_count = free_blocks_count =
 109                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 110
 111         if (test_opt(sb, DEBUG))
 112                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 113                        "(%d free, %u reserved)\n",
 114                        ext4_bg_has_super(sb, input->group) ? "normal" :
 115                        "no-super", input->group, input->blocks_count,
 116                        free_blocks_count, input->reserved_blocks);
 117
 118         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 119         if (offset != 0)
 120                         ext4_warning(sb, "Last group not full");
 121         else if (input->reserved_blocks > input->blocks_count / 5)
 122                 ext4_warning(sb, "Reserved blocks too high (%u)",
 123                              input->reserved_blocks);
 124         else if (free_blocks_count < 0)
 125                 ext4_warning(sb, "Bad blocks count %u",
 126                              input->blocks_count);
 127         else if (!(bh = sb_bread(sb, end - 1)))
 128                 ext4_warning(sb, "Cannot read last block (%llu)",
 129                              end - 1);
 130         else if (outside(input->block_bitmap, start, end))
 131                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 132                              (unsigned long long)input->block_bitmap);
 133         else if (outside(input->inode_bitmap, start, end))
 134                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 135                              (unsigned long long)input->inode_bitmap);
 136         else if (outside(input->inode_table, start, end) ||
 137                  outside(itend - 1, start, end))
 138                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 139                              (unsigned long long)input->inode_table, itend - 1);
 140         else if (input->inode_bitmap == input->block_bitmap)
 141                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 142                              (unsigned long long)input->block_bitmap);
 143         else if (inside(input->block_bitmap, input->inode_table, itend))
 144                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 145                              "(%llu-%llu)",
 146                              (unsigned long long)input->block_bitmap,
 147                              (unsigned long long)input->inode_table, itend - 1);
 148         else if (inside(input->inode_bitmap, input->inode_table, itend))
 149                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 150                              "(%llu-%llu)",
 151                              (unsigned long long)input->inode_bitmap,
 152                              (unsigned long long)input->inode_table, itend - 1);
 153         else if (inside(input->block_bitmap, start, metaend))
 154                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 155                              (unsigned long long)input->block_bitmap,
 156                              start, metaend - 1);
 157         else if (inside(input->inode_bitmap, start, metaend))
 158                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 159                              (unsigned long long)input->inode_bitmap,
 160                              start, metaend - 1);
 161         else if (inside(input->inode_table, start, metaend) ||
 162                  inside(itend - 1, start, metaend))
 163                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 164                              "(%llu-%llu)",
 165                              (unsigned long long)input->inode_table,
 166                              itend - 1, start, metaend - 1);
 167         else
 168                 err = 0;
 169         brelse(bh);
 170
 171         return err;
 172 }
 173
 174 /*
 175  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 176  * group each time.
 177  */
 178 struct ext4_new_flex_group_data {
 179         struct ext4_new_group_data *groups;     /* new_group_data for groups
 180                                                    in the flex group */
 181         __u16 *bg_flags;                        /* block group flags of groups
 182                                                    in @groups */
 183         ext4_group_t count;                     /* number of groups in @groups
 184                                                  */
 185 };
 186
 187 /*
 188  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 189  * @flexbg_size.
 190  *
 191  * Returns NULL on failure otherwise address of the allocated structure.
 192  */
 193 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 194 {
 195         struct ext4_new_flex_group_data *flex_gd;
 196
 197         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 198         if (flex_gd == NULL)
 199                 goto out3;
 200
 201         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 202                 goto out2;
 203         flex_gd->count = flexbg_size;
 204
 205         flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 206                                   flexbg_size, GFP_NOFS);
 207         if (flex_gd->groups == NULL)
 208                 goto out2;
 209
 210         flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 211         if (flex_gd->bg_flags == NULL)
 212                 goto out1;
 213
 214         return flex_gd;
 215
 216 out1:
 217         kfree(flex_gd->groups);
 218 out2:
 219         kfree(flex_gd);
 220 out3:
 221         return NULL;
 222 }
 223
 224 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 225 {
 226         kfree(flex_gd->bg_flags);
 227         kfree(flex_gd->groups);
 228         kfree(flex_gd);
 229 }
 230
 231 /*
 232  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 233  * and inode tables for a flex group.
 234  *
 235  * This function is used by 64bit-resize.  Note that this function allocates
 236  * group tables from the 1st group of groups contained by @flexgd, which may
 237  * be a partial of a flex group.
 238  *
 239  * @sb: super block of fs to which the groups belongs
 240  *
 241  * Returns 0 on a successful allocation of the metadata blocks in the
 242  * block group.
 243  */
 244 static int ext4_alloc_group_tables(struct super_block *sb,
 245                                 struct ext4_new_flex_group_data *flex_gd,
 246                                 int flexbg_size)
 247 {
 248         struct ext4_new_group_data *group_data = flex_gd->groups;
 249         ext4_fsblk_t start_blk;
 250         ext4_fsblk_t last_blk;
 251         ext4_group_t src_group;
 252         ext4_group_t bb_index = 0;
 253         ext4_group_t ib_index = 0;
 254         ext4_group_t it_index = 0;
 255         ext4_group_t group;
 256         ext4_group_t last_group;
 257         unsigned overhead;
 258         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 259
 260         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 261
 262         src_group = group_data[0].group;
 263         last_group  = src_group + flex_gd->count - 1;
 264
 265         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 266                (last_group & ~(flexbg_size - 1))));
 267 next_group:
 268         group = group_data[0].group;
 269         if (src_group >= group_data[0].group + flex_gd->count)
 270                 return -ENOSPC;
 271         start_blk = ext4_group_first_block_no(sb, src_group);
 272         last_blk = start_blk + group_data[src_group - group].blocks_count;
 273
 274         overhead = ext4_group_overhead_blocks(sb, src_group);
 275
 276         start_blk += overhead;
 277
 278         /* We collect contiguous blocks as much as possible. */
 279         src_group++;
 280         for (; src_group <= last_group; src_group++) {
 281                 overhead = ext4_group_overhead_blocks(sb, src_group);
 282                 if (overhead == 0)
 283                         last_blk += group_data[src_group - group].blocks_count;
 284                 else
 285                         break;
 286         }
 287
 288         /* Allocate block bitmaps */
 289         for (; bb_index < flex_gd->count; bb_index++) {
 290                 if (start_blk >= last_blk)
 291                         goto next_group;
 292                 group_data[bb_index].block_bitmap = start_blk++;
 293                 group = ext4_get_group_number(sb, start_blk - 1);
 294                 group -= group_data[0].group;
 295                 group_data[group].free_blocks_count--;
 296                 flex_gd->bg_flags[group] &= uninit_mask;
 297         }
 298
 299         /* Allocate inode bitmaps */
 300         for (; ib_index < flex_gd->count; ib_index++) {
 301                 if (start_blk >= last_blk)
 302                         goto next_group;
 303                 group_data[ib_index].inode_bitmap = start_blk++;
 304                 group = ext4_get_group_number(sb, start_blk - 1);
 305                 group -= group_data[0].group;
 306                 group_data[group].free_blocks_count--;
 307                 flex_gd->bg_flags[group] &= uninit_mask;
 308         }
 309
 310         /* Allocate inode tables */
 311         for (; it_index < flex_gd->count; it_index++) {
 312                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 313                 ext4_fsblk_t next_group_start;
 314
 315                 if (start_blk + itb > last_blk)
 316                         goto next_group;
 317                 group_data[it_index].inode_table = start_blk;
 318                 group = ext4_get_group_number(sb, start_blk);
 319                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 320                 group -= group_data[0].group;
 321
 322                 if (start_blk + itb > next_group_start) {
 323                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 324                         overhead = start_blk + itb - next_group_start;
 325                         group_data[group + 1].free_blocks_count -= overhead;
 326                         itb -= overhead;
 327                 }
 328
 329                 group_data[group].free_blocks_count -= itb;
 330                 flex_gd->bg_flags[group] &= uninit_mask;
 331                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 332         }
 333
 334         if (test_opt(sb, DEBUG)) {
 335                 int i;
 336                 group = group_data[0].group;
 337
 338                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 339                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 340                        flexbg_size);
 341
 342                 for (i = 0; i < flex_gd->count; i++) {
 343                         printk(KERN_DEBUG "adding %s group %u: %u "
 344                                "blocks (%d free)\n",
 345                                ext4_bg_has_super(sb, group + i) ? "normal" :
 346                                "no-super", group + i,
 347                                group_data[i].blocks_count,
 348                                group_data[i].free_blocks_count);
 349                 }
 350         }
 351         return 0;
 352 }
 353
 354 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 355                                   ext4_fsblk_t blk)
 356 {
 357         struct buffer_head *bh;
 358         int err;
 359
 360         bh = sb_getblk(sb, blk);
 361         if (unlikely(!bh))
 362                 return ERR_PTR(-ENOMEM);
 363         BUFFER_TRACE(bh, "get_write_access");
 364         if ((err = ext4_journal_get_write_access(handle, bh))) {
 365                 brelse(bh);
 366                 bh = ERR_PTR(err);
 367         } else {
 368                 memset(bh->b_data, 0, sb->s_blocksize);
 369                 set_buffer_uptodate(bh);
 370         }
 371
 372         return bh;
 373 }
 374
 375 /*
 376  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 377  * If that fails, restart the transaction & regain write access for the
 378  * buffer head which is used for block_bitmap modifications.
 379  */
 380 static int extend_or_restart_transaction(handle_t *handle, int thresh)
 381 {
 382         int err;
 383
 384         if (ext4_handle_has_enough_credits(handle, thresh))
 385                 return 0;
 386
 387         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 388         if (err < 0)
 389                 return err;
 390         if (err) {
 391                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 392                 if (err)
 393                         return err;
 394         }
 395
 396         return 0;
 397 }
 398
 399 /*
 400  * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 401  *
 402  * Helper function for ext4_setup_new_group_blocks() which set .
 403  *
 404  * @sb: super block
 405  * @handle: journal handle
 406  * @flex_gd: flex group data
 407  */
 408 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 409                         struct ext4_new_flex_group_data *flex_gd,
 410                         ext4_fsblk_t block, ext4_group_t count)
 411 {
 412         ext4_group_t count2;
 413
 414         ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 415         for (count2 = count; count > 0; count -= count2, block += count2) {
 416                 ext4_fsblk_t start;
 417                 struct buffer_head *bh;
 418                 ext4_group_t group;
 419                 int err;
 420
 421                 group = ext4_get_group_number(sb, block);
 422                 start = ext4_group_first_block_no(sb, group);
 423                 group -= flex_gd->groups[0].group;
 424
 425                 count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
 426                 if (count2 > count)
 427                         count2 = count;
 428
 429                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 430                         BUG_ON(flex_gd->count > 1);
 431                         continue;
 432                 }
 433
 434                 err = extend_or_restart_transaction(handle, 1);
 435                 if (err)
 436                         return err;
 437
 438                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 439                 if (unlikely(!bh))
 440                         return -ENOMEM;
 441
 442                 BUFFER_TRACE(bh, "get_write_access");
 443                 err = ext4_journal_get_write_access(handle, bh);
 444                 if (err)
 445                         return err;
 446                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 447                            block - start, count2);
 448                 ext4_set_bits(bh->b_data, block - start, count2);
 449
 450                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 451                 if (unlikely(err))
 452                         return err;
 453                 brelse(bh);
 454         }
 455
 456         return 0;
 457 }
 458
 459 /*
 460  * Set up the block and inode bitmaps, and the inode table for the new groups.
 461  * This doesn't need to be part of the main transaction, since we are only
 462  * changing blocks outside the actual filesystem.  We still do journaling to
 463  * ensure the recovery is correct in case of a failure just after resize.
 464  * If any part of this fails, we simply abort the resize.
 465  *
 466  * setup_new_flex_group_blocks handles a flex group as follow:
 467  *  1. copy super block and GDT, and initialize group tables if necessary.
 468  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 469  *     super block and GDT.
 470  *  2. allocate group tables in block bitmaps, that is, set bits in block
 471  *     bitmap for blocks taken by group tables.
 472  */
 473 static int setup_new_flex_group_blocks(struct super_block *sb,
 474                                 struct ext4_new_flex_group_data *flex_gd)
 475 {
 476         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 477         ext4_fsblk_t start;
 478         ext4_fsblk_t block;
 479         struct ext4_sb_info *sbi = EXT4_SB(sb);
 480         struct ext4_super_block *es = sbi->s_es;
 481         struct ext4_new_group_data *group_data = flex_gd->groups;
 482         __u16 *bg_flags = flex_gd->bg_flags;
 483         handle_t *handle;
 484         ext4_group_t group, count;
 485         struct buffer_head *bh = NULL;
 486         int reserved_gdb, i, j, err = 0, err2;
 487         int meta_bg;
 488
 489         BUG_ON(!flex_gd->count || !group_data ||
 490                group_data[0].group != sbi->s_groups_count);
 491
 492         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 493         meta_bg = ext4_has_feature_meta_bg(sb);
 494
 495         /* This transaction may be extended/restarted along the way */
 496         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 497         if (IS_ERR(handle))
 498                 return PTR_ERR(handle);
 499
 500         group = group_data[0].group;
 501         for (i = 0; i < flex_gd->count; i++, group++) {
 502                 unsigned long gdblocks;
 503                 ext4_grpblk_t overhead;
 504
 505                 gdblocks = ext4_bg_num_gdb(sb, group);
 506                 start = ext4_group_first_block_no(sb, group);
 507
 508                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 509                         goto handle_itb;
 510
 511                 if (meta_bg == 1) {
 512                         ext4_group_t first_group;
 513                         first_group = ext4_meta_bg_first_group(sb, group);
 514                         if (first_group != group + 1 &&
 515                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 516                                 goto handle_itb;
 517                 }
 518
 519                 block = start + ext4_bg_has_super(sb, group);
 520                 /* Copy all of the GDT blocks into the backup in this group */
 521                 for (j = 0; j < gdblocks; j++, block++) {
 522                         struct buffer_head *gdb;
 523
 524                         ext4_debug("update backup group %#04llx\n", block);
 525                         err = extend_or_restart_transaction(handle, 1);
 526                         if (err)
 527                                 goto out;
 528
 529                         gdb = sb_getblk(sb, block);
 530                         if (unlikely(!gdb)) {
 531                                 err = -ENOMEM;
 532                                 goto out;
 533                         }
 534
 535                         BUFFER_TRACE(gdb, "get_write_access");
 536                         err = ext4_journal_get_write_access(handle, gdb);
 537                         if (err) {
 538                                 brelse(gdb);
 539                                 goto out;
 540                         }
 541                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 542                                gdb->b_size);
 543                         set_buffer_uptodate(gdb);
 544
 545                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 546                         if (unlikely(err)) {
 547                                 brelse(gdb);
 548                                 goto out;
 549                         }
 550                         brelse(gdb);
 551                 }
 552
 553                 /* Zero out all of the reserved backup group descriptor
 554                  * table blocks
 555                  */
 556                 if (ext4_bg_has_super(sb, group)) {
 557                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 558                                         reserved_gdb, GFP_NOFS);
 559                         if (err)
 560                                 goto out;
 561                 }
 562
 563 handle_itb:
 564                 /* Initialize group tables of the grop @group */
 565                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 566                         goto handle_bb;
 567
 568                 /* Zero out all of the inode table blocks */
 569                 block = group_data[i].inode_table;
 570                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 571                            block, sbi->s_itb_per_group);
 572                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 573                                        GFP_NOFS);
 574                 if (err)
 575                         goto out;
 576
 577 handle_bb:
 578                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 579                         goto handle_ib;
 580
 581                 /* Initialize block bitmap of the @group */
 582                 block = group_data[i].block_bitmap;
 583                 err = extend_or_restart_transaction(handle, 1);
 584                 if (err)
 585                         goto out;
 586
 587                 bh = bclean(handle, sb, block);
 588                 if (IS_ERR(bh)) {
 589                         err = PTR_ERR(bh);
 590                         bh = NULL;
 591                         goto out;
 592                 }
 593                 overhead = ext4_group_overhead_blocks(sb, group);
 594                 if (overhead != 0) {
 595                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 596                                    start);
 597                         ext4_set_bits(bh->b_data, 0, overhead);
 598                 }
 599                 ext4_mark_bitmap_end(group_data[i].blocks_count,
 600                                      sb->s_blocksize * 8, bh->b_data);
 601                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 602                 if (err)
 603                         goto out;
 604                 brelse(bh);
 605
 606 handle_ib:
 607                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 608                         continue;
 609
 610                 /* Initialize inode bitmap of the @group */
 611                 block = group_data[i].inode_bitmap;
 612                 err = extend_or_restart_transaction(handle, 1);
 613                 if (err)
 614                         goto out;
 615                 /* Mark unused entries in inode bitmap used */
 616                 bh = bclean(handle, sb, block);
 617                 if (IS_ERR(bh)) {
 618                         err = PTR_ERR(bh);
 619                         bh = NULL;
 620                         goto out;
 621                 }
 622
 623                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 624                                      sb->s_blocksize * 8, bh->b_data);
 625                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 626                 if (err)
 627                         goto out;
 628                 brelse(bh);
 629         }
 630         bh = NULL;
 631
 632         /* Mark group tables in block bitmap */
 633         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 634                 count = group_table_count[j];
 635                 start = (&group_data[0].block_bitmap)[j];
 636                 block = start;
 637                 for (i = 1; i < flex_gd->count; i++) {
 638                         block += group_table_count[j];
 639                         if (block == (&group_data[i].block_bitmap)[j]) {
 640                                 count += group_table_count[j];
 641                                 continue;
 642                         }
 643                         err = set_flexbg_block_bitmap(sb, handle,
 644                                                 flex_gd, start, count);
 645                         if (err)
 646                                 goto out;
 647                         count = group_table_count[j];
 648                         start = (&group_data[i].block_bitmap)[j];
 649                         block = start;
 650                 }
 651
 652                 if (count) {
 653                         err = set_flexbg_block_bitmap(sb, handle,
 654                                                 flex_gd, start, count);
 655                         if (err)
 656                                 goto out;
 657                 }
 658         }
 659
 660 out:
 661         brelse(bh);
 662         err2 = ext4_journal_stop(handle);
 663         if (err2 && !err)
 664                 err = err2;
 665
 666         return err;
 667 }
 668
 669 /*
 670  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 671  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 672  * calling this for the first time.  In a sparse filesystem it will be the
 673  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 674  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 675  */
 676 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 677                                   unsigned *five, unsigned *seven)
 678 {
 679         unsigned *min = three;
 680         int mult = 3;
 681         unsigned ret;
 682
 683         if (!ext4_has_feature_sparse_super(sb)) {
 684                 ret = *min;
 685                 *min += 1;
 686                 return ret;
 687         }
 688
 689         if (*five < *min) {
 690                 min = five;
 691                 mult = 5;
 692         }
 693         if (*seven < *min) {
 694                 min = seven;
 695                 mult = 7;
 696         }
 697
 698         ret = *min;
 699         *min *= mult;
 700
 701         return ret;
 702 }
 703
 704 /*
 705  * Check that all of the backup GDT blocks are held in the primary GDT block.
 706  * It is assumed that they are stored in group order.  Returns the number of
 707  * groups in current filesystem that have BACKUPS, or -ve error code.
 708  */
 709 static int verify_reserved_gdb(struct super_block *sb,
 710                                ext4_group_t end,
 711                                struct buffer_head *primary)
 712 {
 713         const ext4_fsblk_t blk = primary->b_blocknr;
 714         unsigned three = 1;
 715         unsigned five = 5;
 716         unsigned seven = 7;
 717         unsigned grp;
 718         __le32 *p = (__le32 *)primary->b_data;
 719         int gdbackups = 0;
 720
 721         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 722                 if (le32_to_cpu(*p++) !=
 723                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 724                         ext4_warning(sb, "reserved GDT %llu"
 725                                      " missing grp %d (%llu)",
 726                                      blk, grp,
 727                                      grp *
 728                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 729                                      blk);
 730                         return -EINVAL;
 731                 }
 732                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 733                         return -EFBIG;
 734         }
 735
 736         return gdbackups;
 737 }
 738
 739 /*
 740  * Called when we need to bring a reserved group descriptor table block into
 741  * use from the resize inode.  The primary copy of the new GDT block currently
 742  * is an indirect block (under the double indirect block in the resize inode).
 743  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 744  * block, in group order.  Even though we know all the block numbers we need,
 745  * we check to ensure that the resize inode has actually reserved these blocks.
 746  *
 747  * Don't need to update the block bitmaps because the blocks are still in use.
 748  *
 749  * We get all of the error cases out of the way, so that we are sure to not
 750  * fail once we start modifying the data on disk, because JBD has no rollback.
 751  */
 752 static int add_new_gdb(handle_t *handle, struct inode *inode,
 753                        ext4_group_t group)
 754 {
 755         struct super_block *sb = inode->i_sb;
 756         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 757         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 758         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 759         struct buffer_head **o_group_desc, **n_group_desc;
 760         struct buffer_head *dind;
 761         struct buffer_head *gdb_bh;
 762         int gdbackups;
 763         struct ext4_iloc iloc;
 764         __le32 *data;
 765         int err;
 766
 767         if (test_opt(sb, DEBUG))
 768                 printk(KERN_DEBUG
 769                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 770                        gdb_num);
 771
 772         gdb_bh = sb_bread(sb, gdblock);
 773         if (!gdb_bh)
 774                 return -EIO;
 775
 776         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 777         if (gdbackups < 0) {
 778                 err = gdbackups;
 779                 goto exit_bh;
 780         }
 781
 782         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 783         dind = sb_bread(sb, le32_to_cpu(*data));
 784         if (!dind) {
 785                 err = -EIO;
 786                 goto exit_bh;
 787         }
 788
 789         data = (__le32 *)dind->b_data;
 790         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 791                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 792                              group, gdblock);
 793                 err = -EINVAL;
 794                 goto exit_dind;
 795         }
 796
 797         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 798         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 799         if (unlikely(err))
 800                 goto exit_dind;
 801
 802         BUFFER_TRACE(gdb_bh, "get_write_access");
 803         err = ext4_journal_get_write_access(handle, gdb_bh);
 804         if (unlikely(err))
 805                 goto exit_dind;
 806
 807         BUFFER_TRACE(dind, "get_write_access");
 808         err = ext4_journal_get_write_access(handle, dind);
 809         if (unlikely(err))
 810                 ext4_std_error(sb, err);
 811
 812         /* ext4_reserve_inode_write() gets a reference on the iloc */
 813         err = ext4_reserve_inode_write(handle, inode, &iloc);
 814         if (unlikely(err))
 815                 goto exit_dind;
 816
 817         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 818                                      sizeof(struct buffer_head *),
 819                                      GFP_NOFS);
 820         if (!n_group_desc) {
 821                 err = -ENOMEM;
 822                 ext4_warning(sb, "not enough memory for %lu groups",
 823                              gdb_num + 1);
 824                 goto exit_inode;
 825         }
 826
 827         /*
 828          * Finally, we have all of the possible failures behind us...
 829          *
 830          * Remove new GDT block from inode double-indirect block and clear out
 831          * the new GDT block for use (which also "frees" the backup GDT blocks
 832          * from the reserved inode).  We don't need to change the bitmaps for
 833          * these blocks, because they are marked as in-use from being in the
 834          * reserved inode, and will become GDT blocks (primary and backup).
 835          */
 836         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 837         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 838         if (unlikely(err)) {
 839                 ext4_std_error(sb, err);
 840                 goto exit_inode;
 841         }
 842         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 843         ext4_mark_iloc_dirty(handle, inode, &iloc);
 844         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 845         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 846         if (unlikely(err)) {
 847                 ext4_std_error(sb, err);
 848                 goto exit_inode;
 849         }
 850         brelse(dind);
 851
 852         o_group_desc = EXT4_SB(sb)->s_group_desc;
 853         memcpy(n_group_desc, o_group_desc,
 854                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 855         n_group_desc[gdb_num] = gdb_bh;
 856         EXT4_SB(sb)->s_group_desc = n_group_desc;
 857         EXT4_SB(sb)->s_gdb_count++;
 858         kvfree(o_group_desc);
 859
 860         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 861         err = ext4_handle_dirty_super(handle, sb);
 862         if (err)
 863                 ext4_std_error(sb, err);
 864
 865         return err;
 866
 867 exit_inode:
 868         kvfree(n_group_desc);
 869         brelse(iloc.bh);
 870 exit_dind:
 871         brelse(dind);
 872 exit_bh:
 873         brelse(gdb_bh);
 874
 875         ext4_debug("leaving with error %d\n", err);
 876         return err;
 877 }
 878
 879 /*
 880  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 881  */
 882 static int add_new_gdb_meta_bg(struct super_block *sb,
 883                                handle_t *handle, ext4_group_t group) {
 884         ext4_fsblk_t gdblock;
 885         struct buffer_head *gdb_bh;
 886         struct buffer_head **o_group_desc, **n_group_desc;
 887         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 888         int err;
 889
 890         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 891                    ext4_bg_has_super(sb, group);
 892         gdb_bh = sb_bread(sb, gdblock);
 893         if (!gdb_bh)
 894                 return -EIO;
 895         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 896                                      sizeof(struct buffer_head *),
 897                                      GFP_NOFS);
 898         if (!n_group_desc) {
 899                 err = -ENOMEM;
 900                 ext4_warning(sb, "not enough memory for %lu groups",
 901                              gdb_num + 1);
 902                 return err;
 903         }
 904
 905         o_group_desc = EXT4_SB(sb)->s_group_desc;
 906         memcpy(n_group_desc, o_group_desc,
 907                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 908         n_group_desc[gdb_num] = gdb_bh;
 909         EXT4_SB(sb)->s_group_desc = n_group_desc;
 910         EXT4_SB(sb)->s_gdb_count++;
 911         kvfree(o_group_desc);
 912         BUFFER_TRACE(gdb_bh, "get_write_access");
 913         err = ext4_journal_get_write_access(handle, gdb_bh);
 914         if (unlikely(err))
 915                 brelse(gdb_bh);
 916         return err;
 917 }
 918
 919 /*
 920  * Called when we are adding a new group which has a backup copy of each of
 921  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 922  * We need to add these reserved backup GDT blocks to the resize inode, so
 923  * that they are kept for future resizing and not allocated to files.
 924  *
 925  * Each reserved backup GDT block will go into a different indirect block.
 926  * The indirect blocks are actually the primary reserved GDT blocks,
 927  * so we know in advance what their block numbers are.  We only get the
 928  * double-indirect block to verify it is pointing to the primary reserved
 929  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 930  * backup GDT blocks are stored in their reserved primary GDT block.
 931  */
 932 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 933                               ext4_group_t group)
 934 {
 935         struct super_block *sb = inode->i_sb;
 936         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 937         struct buffer_head **primary;
 938         struct buffer_head *dind;
 939         struct ext4_iloc iloc;
 940         ext4_fsblk_t blk;
 941         __le32 *data, *end;
 942         int gdbackups = 0;
 943         int res, i;
 944         int err;
 945
 946         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 947         if (!primary)
 948                 return -ENOMEM;
 949
 950         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 951         dind = sb_bread(sb, le32_to_cpu(*data));
 952         if (!dind) {
 953                 err = -EIO;
 954                 goto exit_free;
 955         }
 956
 957         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 958         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 959                                          EXT4_ADDR_PER_BLOCK(sb));
 960         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 961
 962         /* Get each reserved primary GDT block and verify it holds backups */
 963         for (res = 0; res < reserved_gdb; res++, blk++) {
 964                 if (le32_to_cpu(*data) != blk) {
 965                         ext4_warning(sb, "reserved block %llu"
 966                                      " not at offset %ld",
 967                                      blk,
 968                                      (long)(data - (__le32 *)dind->b_data));
 969                         err = -EINVAL;
 970                         goto exit_bh;
 971                 }
 972                 primary[res] = sb_bread(sb, blk);
 973                 if (!primary[res]) {
 974                         err = -EIO;
 975                         goto exit_bh;
 976                 }
 977                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 978                 if (gdbackups < 0) {
 979                         brelse(primary[res]);
 980                         err = gdbackups;
 981                         goto exit_bh;
 982                 }
 983                 if (++data >= end)
 984                         data = (__le32 *)dind->b_data;
 985         }
 986
 987         for (i = 0; i < reserved_gdb; i++) {
 988                 BUFFER_TRACE(primary[i], "get_write_access");
 989                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
 990                         goto exit_bh;
 991         }
 992
 993         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 994                 goto exit_bh;
 995
 996         /*
 997          * Finally we can add each of the reserved backup GDT blocks from
 998          * the new group to its reserved primary GDT block.
 999          */
1000         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1001         for (i = 0; i < reserved_gdb; i++) {
1002                 int err2;
1003                 data = (__le32 *)primary[i]->b_data;
1004                 /* printk("reserving backup %lu[%u] = %lu\n",
1005                        primary[i]->b_blocknr, gdbackups,
1006                        blk + primary[i]->b_blocknr); */
1007                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1008                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1009                 if (!err)
1010                         err = err2;
1011         }
1012         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
1013         ext4_mark_iloc_dirty(handle, inode, &iloc);
1014
1015 exit_bh:
1016         while (--res >= 0)
1017                 brelse(primary[res]);
1018         brelse(dind);
1019
1020 exit_free:
1021         kfree(primary);
1022
1023         return err;
1024 }
1025
1026 /*
1027  * Update the backup copies of the ext4 metadata.  These don't need to be part
1028  * of the main resize transaction, because e2fsck will re-write them if there
1029  * is a problem (basically only OOM will cause a problem).  However, we
1030  * _should_ update the backups if possible, in case the primary gets trashed
1031  * for some reason and we need to run e2fsck from a backup superblock.  The
1032  * important part is that the new block and inode counts are in the backup
1033  * superblocks, and the location of the new group metadata in the GDT backups.
1034  *
1035  * We do not need take the s_resize_lock for this, because these
1036  * blocks are not otherwise touched by the filesystem code when it is
1037  * mounted.  We don't need to worry about last changing from
1038  * sbi->s_groups_count, because the worst that can happen is that we
1039  * do not copy the full number of backups at this time.  The resize
1040  * which changed s_groups_count will backup again.
1041  */
1042 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1043                            int size, int meta_bg)
1044 {
1045         struct ext4_sb_info *sbi = EXT4_SB(sb);
1046         ext4_group_t last;
1047         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1048         unsigned three = 1;
1049         unsigned five = 5;
1050         unsigned seven = 7;
1051         ext4_group_t group = 0;
1052         int rest = sb->s_blocksize - size;
1053         handle_t *handle;
1054         int err = 0, err2;
1055
1056         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1057         if (IS_ERR(handle)) {
1058                 group = 1;
1059                 err = PTR_ERR(handle);
1060                 goto exit_err;
1061         }
1062
1063         if (meta_bg == 0) {
1064                 group = ext4_list_backups(sb, &three, &five, &seven);
1065                 last = sbi->s_groups_count;
1066         } else {
1067                 group = ext4_get_group_number(sb, blk_off) + 1;
1068                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1069         }
1070
1071         while (group < sbi->s_groups_count) {
1072                 struct buffer_head *bh;
1073                 ext4_fsblk_t backup_block;
1074
1075                 /* Out of journal space, and can't get more - abort - so sad */
1076                 if (ext4_handle_valid(handle) &&
1077                     handle->h_buffer_credits == 0 &&
1078                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1079                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1080                         break;
1081
1082                 if (meta_bg == 0)
1083                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1084                 else
1085                         backup_block = (ext4_group_first_block_no(sb, group) +
1086                                         ext4_bg_has_super(sb, group));
1087
1088                 bh = sb_getblk(sb, backup_block);
1089                 if (unlikely(!bh)) {
1090                         err = -ENOMEM;
1091                         break;
1092                 }
1093                 ext4_debug("update metadata backup %llu(+%llu)\n",
1094                            backup_block, backup_block -
1095                            ext4_group_first_block_no(sb, group));
1096                 BUFFER_TRACE(bh, "get_write_access");
1097                 if ((err = ext4_journal_get_write_access(handle, bh)))
1098                         break;
1099                 lock_buffer(bh);
1100                 memcpy(bh->b_data, data, size);
1101                 if (rest)
1102                         memset(bh->b_data + size, 0, rest);
1103                 set_buffer_uptodate(bh);
1104                 unlock_buffer(bh);
1105                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1106                 if (unlikely(err))
1107                         ext4_std_error(sb, err);
1108                 brelse(bh);
1109
1110                 if (meta_bg == 0)
1111                         group = ext4_list_backups(sb, &three, &five, &seven);
1112                 else if (group == last)
1113                         break;
1114                 else
1115                         group = last;
1116         }
1117         if ((err2 = ext4_journal_stop(handle)) && !err)
1118                 err = err2;
1119
1120         /*
1121          * Ugh! Need to have e2fsck write the backup copies.  It is too
1122          * late to revert the resize, we shouldn't fail just because of
1123          * the backup copies (they are only needed in case of corruption).
1124          *
1125          * However, if we got here we have a journal problem too, so we
1126          * can't really start a transaction to mark the superblock.
1127          * Chicken out and just set the flag on the hope it will be written
1128          * to disk, and if not - we will simply wait until next fsck.
1129          */
1130 exit_err:
1131         if (err) {
1132                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1133                              "forcing fsck on next reboot", group, err);
1134                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1135                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1136                 mark_buffer_dirty(sbi->s_sbh);
1137         }
1138 }
1139
1140 /*
1141  * ext4_add_new_descs() adds @count group descriptor of groups
1142  * starting at @group
1143  *
1144  * @handle: journal handle
1145  * @sb: super block
1146  * @group: the group no. of the first group desc to be added
1147  * @resize_inode: the resize inode
1148  * @count: number of group descriptors to be added
1149  */
1150 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1151                               ext4_group_t group, struct inode *resize_inode,
1152                               ext4_group_t count)
1153 {
1154         struct ext4_sb_info *sbi = EXT4_SB(sb);
1155         struct ext4_super_block *es = sbi->s_es;
1156         struct buffer_head *gdb_bh;
1157         int i, gdb_off, gdb_num, err = 0;
1158         int meta_bg;
1159
1160         meta_bg = ext4_has_feature_meta_bg(sb);
1161         for (i = 0; i < count; i++, group++) {
1162                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1163                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1164
1165                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1166                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1167
1168                 /*
1169                  * We will only either add reserved group blocks to a backup group
1170                  * or remove reserved blocks for the first group in a new group block.
1171                  * Doing both would be mean more complex code, and sane people don't
1172                  * use non-sparse filesystems anymore.  This is already checked above.
1173                  */
1174                 if (gdb_off) {
1175                         gdb_bh = sbi->s_group_desc[gdb_num];
1176                         BUFFER_TRACE(gdb_bh, "get_write_access");
1177                         err = ext4_journal_get_write_access(handle, gdb_bh);
1178
1179                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1180                                 err = reserve_backup_gdb(handle, resize_inode, group);
1181                 } else if (meta_bg != 0) {
1182                         err = add_new_gdb_meta_bg(sb, handle, group);
1183                 } else {
1184                         err = add_new_gdb(handle, resize_inode, group);
1185                 }
1186                 if (err)
1187                         break;
1188         }
1189         return err;
1190 }
1191
1192 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1193 {
1194         struct buffer_head *bh = sb_getblk(sb, block);
1195         if (unlikely(!bh))
1196                 return NULL;
1197         if (!bh_uptodate_or_lock(bh)) {
1198                 if (bh_submit_read(bh) < 0) {
1199                         brelse(bh);
1200                         return NULL;
1201                 }
1202         }
1203
1204         return bh;
1205 }
1206
1207 static int ext4_set_bitmap_checksums(struct super_block *sb,
1208                                      ext4_group_t group,
1209                                      struct ext4_group_desc *gdp,
1210                                      struct ext4_new_group_data *group_data)
1211 {
1212         struct buffer_head *bh;
1213
1214         if (!ext4_has_metadata_csum(sb))
1215                 return 0;
1216
1217         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1218         if (!bh)
1219                 return -EIO;
1220         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1221                                    EXT4_INODES_PER_GROUP(sb) / 8);
1222         brelse(bh);
1223
1224         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1225         if (!bh)
1226                 return -EIO;
1227         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1228         brelse(bh);
1229
1230         return 0;
1231 }
1232
1233 /*
1234  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1235  */
1236 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1237                                 struct ext4_new_flex_group_data *flex_gd)
1238 {
1239         struct ext4_new_group_data      *group_data = flex_gd->groups;
1240         struct ext4_group_desc          *gdp;
1241         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1242         struct buffer_head              *gdb_bh;
1243         ext4_group_t                    group;
1244         __u16                           *bg_flags = flex_gd->bg_flags;
1245         int                             i, gdb_off, gdb_num, err = 0;
1246
1247
1248         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1249                 group = group_data->group;
1250
1251                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1252                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1253
1254                 /*
1255                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1256                  */
1257                 gdb_bh = sbi->s_group_desc[gdb_num];
1258                 /* Update group descriptor block for new group */
1259                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1260                                                  gdb_off * EXT4_DESC_SIZE(sb));
1261
1262                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1263                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1264                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1265                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1266                 if (err) {
1267                         ext4_std_error(sb, err);
1268                         break;
1269                 }
1270
1271                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1272                 ext4_free_group_clusters_set(sb, gdp,
1273                         EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1274                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1275                 if (ext4_has_group_desc_csum(sb))
1276                         ext4_itable_unused_set(sb, gdp,
1277                                                EXT4_INODES_PER_GROUP(sb));
1278                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1279                 ext4_group_desc_csum_set(sb, group, gdp);
1280
1281                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1282                 if (unlikely(err)) {
1283                         ext4_std_error(sb, err);
1284                         break;
1285                 }
1286
1287                 /*
1288                  * We can allocate memory for mb_alloc based on the new group
1289                  * descriptor
1290                  */
1291                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1292                 if (err)
1293                         break;
1294         }
1295         return err;
1296 }
1297
1298 /*
1299  * ext4_update_super() updates the super block so that the newly added
1300  * groups can be seen by the filesystem.
1301  *
1302  * @sb: super block
1303  * @flex_gd: new added groups
1304  */
1305 static void ext4_update_super(struct super_block *sb,
1306                              struct ext4_new_flex_group_data *flex_gd)
1307 {
1308         ext4_fsblk_t blocks_count = 0;
1309         ext4_fsblk_t free_blocks = 0;
1310         ext4_fsblk_t reserved_blocks = 0;
1311         struct ext4_new_group_data *group_data = flex_gd->groups;
1312         struct ext4_sb_info *sbi = EXT4_SB(sb);
1313         struct ext4_super_block *es = sbi->s_es;
1314         int i;
1315
1316         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1317         /*
1318          * Make the new blocks and inodes valid next.  We do this before
1319          * increasing the group count so that once the group is enabled,
1320          * all of its blocks and inodes are already valid.
1321          *
1322          * We always allocate group-by-group, then block-by-block or
1323          * inode-by-inode within a group, so enabling these
1324          * blocks/inodes before the group is live won't actually let us
1325          * allocate the new space yet.
1326          */
1327         for (i = 0; i < flex_gd->count; i++) {
1328                 blocks_count += group_data[i].blocks_count;
1329                 free_blocks += group_data[i].free_blocks_count;
1330         }
1331
1332         reserved_blocks = ext4_r_blocks_count(es) * 100;
1333         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1334         reserved_blocks *= blocks_count;
1335         do_div(reserved_blocks, 100);
1336
1337         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1338         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1339         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1340                      flex_gd->count);
1341         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1342                      flex_gd->count);
1343
1344         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1345         /*
1346          * We need to protect s_groups_count against other CPUs seeing
1347          * inconsistent state in the superblock.
1348          *
1349          * The precise rules we use are:
1350          *
1351          * * Writers must perform a smp_wmb() after updating all
1352          *   dependent data and before modifying the groups count
1353          *
1354          * * Readers must perform an smp_rmb() after reading the groups
1355          *   count and before reading any dependent data.
1356          *
1357          * NB. These rules can be relaxed when checking the group count
1358          * while freeing data, as we can only allocate from a block
1359          * group after serialising against the group count, and we can
1360          * only then free after serialising in turn against that
1361          * allocation.
1362          */
1363         smp_wmb();
1364
1365         /* Update the global fs size fields */
1366         sbi->s_groups_count += flex_gd->count;
1367         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1368                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1369
1370         /* Update the reserved block counts only once the new group is
1371          * active. */
1372         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1373                                 reserved_blocks);
1374
1375         /* Update the free space counts */
1376         percpu_counter_add(&sbi->s_freeclusters_counter,
1377                            EXT4_NUM_B2C(sbi, free_blocks));
1378         percpu_counter_add(&sbi->s_freeinodes_counter,
1379                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1380
1381         ext4_debug("free blocks count %llu",
1382                    percpu_counter_read(&sbi->s_freeclusters_counter));
1383         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1384                 ext4_group_t flex_group;
1385                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1386                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1387                              &sbi->s_flex_groups[flex_group].free_clusters);
1388                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1389                            &sbi->s_flex_groups[flex_group].free_inodes);
1390         }
1391
1392         /*
1393          * Update the fs overhead information
1394          */
1395         ext4_calculate_overhead(sb);
1396
1397         if (test_opt(sb, DEBUG))
1398                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1399                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1400                        blocks_count, free_blocks, reserved_blocks);
1401 }
1402
1403 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1404  * _before_ we start modifying the filesystem, because we cannot abort the
1405  * transaction and not have it write the data to disk.
1406  */
1407 static int ext4_flex_group_add(struct super_block *sb,
1408                                struct inode *resize_inode,
1409                                struct ext4_new_flex_group_data *flex_gd)
1410 {
1411         struct ext4_sb_info *sbi = EXT4_SB(sb);
1412         struct ext4_super_block *es = sbi->s_es;
1413         ext4_fsblk_t o_blocks_count;
1414         ext4_grpblk_t last;
1415         ext4_group_t group;
1416         handle_t *handle;
1417         unsigned reserved_gdb;
1418         int err = 0, err2 = 0, credit;
1419
1420         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1421
1422         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1423         o_blocks_count = ext4_blocks_count(es);
1424         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1425         BUG_ON(last);
1426
1427         err = setup_new_flex_group_blocks(sb, flex_gd);
1428         if (err)
1429                 goto exit;
1430         /*
1431          * We will always be modifying at least the superblock and  GDT
1432          * blocks.  If we are adding a group past the last current GDT block,
1433          * we will also modify the inode and the dindirect block.  If we
1434          * are adding a group with superblock/GDT backups  we will also
1435          * modify each of the reserved GDT dindirect blocks.
1436          */
1437         credit = 3;     /* sb, resize inode, resize inode dindirect */
1438         /* GDT blocks */
1439         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1440         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1441         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1442         if (IS_ERR(handle)) {
1443                 err = PTR_ERR(handle);
1444                 goto exit;
1445         }
1446
1447         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1448         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1449         if (err)
1450                 goto exit_journal;
1451
1452         group = flex_gd->groups[0].group;
1453         BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1454         err = ext4_add_new_descs(handle, sb, group,
1455                                 resize_inode, flex_gd->count);
1456         if (err)
1457                 goto exit_journal;
1458
1459         err = ext4_setup_new_descs(handle, sb, flex_gd);
1460         if (err)
1461                 goto exit_journal;
1462
1463         ext4_update_super(sb, flex_gd);
1464
1465         err = ext4_handle_dirty_super(handle, sb);
1466
1467 exit_journal:
1468         err2 = ext4_journal_stop(handle);
1469         if (!err)
1470                 err = err2;
1471
1472         if (!err) {
1473                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1474                 int gdb_num_end = ((group + flex_gd->count - 1) /
1475                                    EXT4_DESC_PER_BLOCK(sb));
1476                 int meta_bg = ext4_has_feature_meta_bg(sb);
1477                 sector_t old_gdb = 0;
1478
1479                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1480                                sizeof(struct ext4_super_block), 0);
1481                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1482                         struct buffer_head *gdb_bh;
1483
1484                         gdb_bh = sbi->s_group_desc[gdb_num];
1485                         if (old_gdb == gdb_bh->b_blocknr)
1486                                 continue;
1487                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1488                                        gdb_bh->b_size, meta_bg);
1489                         old_gdb = gdb_bh->b_blocknr;
1490                 }
1491         }
1492 exit:
1493         return err;
1494 }
1495
1496 static int ext4_setup_next_flex_gd(struct super_block *sb,
1497                                     struct ext4_new_flex_group_data *flex_gd,
1498                                     ext4_fsblk_t n_blocks_count,
1499                                     unsigned long flexbg_size)
1500 {
1501         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1502         struct ext4_new_group_data *group_data = flex_gd->groups;
1503         ext4_fsblk_t o_blocks_count;
1504         ext4_group_t n_group;
1505         ext4_group_t group;
1506         ext4_group_t last_group;
1507         ext4_grpblk_t last;
1508         ext4_grpblk_t blocks_per_group;
1509         unsigned long i;
1510
1511         blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1512
1513         o_blocks_count = ext4_blocks_count(es);
1514
1515         if (o_blocks_count == n_blocks_count)
1516                 return 0;
1517
1518         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1519         BUG_ON(last);
1520         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1521
1522         last_group = group | (flexbg_size - 1);
1523         if (last_group > n_group)
1524                 last_group = n_group;
1525
1526         flex_gd->count = last_group - group + 1;
1527
1528         for (i = 0; i < flex_gd->count; i++) {
1529                 int overhead;
1530
1531                 group_data[i].group = group + i;
1532                 group_data[i].blocks_count = blocks_per_group;
1533                 overhead = ext4_group_overhead_blocks(sb, group + i);
1534                 group_data[i].free_blocks_count = blocks_per_group - overhead;
1535                 if (ext4_has_group_desc_csum(sb)) {
1536                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1537                                                EXT4_BG_INODE_UNINIT;
1538                         if (!test_opt(sb, INIT_INODE_TABLE))
1539                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1540                 } else
1541                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1542         }
1543
1544         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1545                 /* We need to initialize block bitmap of last group. */
1546                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1547
1548         if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1549                 group_data[i - 1].blocks_count = last + 1;
1550                 group_data[i - 1].free_blocks_count -= blocks_per_group-
1551                                         last - 1;
1552         }
1553
1554         return 1;
1555 }
1556
1557 /* Add group descriptor data to an existing or new group descriptor block.
1558  * Ensure we handle all possible error conditions _before_ we start modifying
1559  * the filesystem, because we cannot abort the transaction and not have it
1560  * write the data to disk.
1561  *
1562  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1563  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1564  *
1565  * We only need to hold the superblock lock while we are actually adding
1566  * in the new group's counts to the superblock.  Prior to that we have
1567  * not really "added" the group at all.  We re-check that we are still
1568  * adding in the last group in case things have changed since verifying.
1569  */
1570 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1571 {
1572         struct ext4_new_flex_group_data flex_gd;
1573         struct ext4_sb_info *sbi = EXT4_SB(sb);
1574         struct ext4_super_block *es = sbi->s_es;
1575         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1576                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1577         struct inode *inode = NULL;
1578         int gdb_off;
1579         int err;
1580         __u16 bg_flags = 0;
1581
1582         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1583
1584         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1585                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1586                 return -EPERM;
1587         }
1588
1589         if (ext4_blocks_count(es) + input->blocks_count <
1590             ext4_blocks_count(es)) {
1591                 ext4_warning(sb, "blocks_count overflow");
1592                 return -EINVAL;
1593         }
1594
1595         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1596             le32_to_cpu(es->s_inodes_count)) {
1597                 ext4_warning(sb, "inodes_count overflow");
1598                 return -EINVAL;
1599         }
1600
1601         if (reserved_gdb || gdb_off == 0) {
1602                 if (ext4_has_feature_resize_inode(sb) ||
1603                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1604                         ext4_warning(sb,
1605                                      "No reserved GDT blocks, can't resize");
1606                         return -EPERM;
1607                 }
1608                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1609                 if (IS_ERR(inode)) {
1610                         ext4_warning(sb, "Error opening resize inode");
1611                         return PTR_ERR(inode);
1612                 }
1613         }
1614
1615
1616         err = verify_group_input(sb, input);
1617         if (err)
1618                 goto out;
1619
1620         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1621         if (err)
1622                 goto out;
1623
1624         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1625         if (err)
1626                 goto out;
1627
1628         flex_gd.count = 1;
1629         flex_gd.groups = input;
1630         flex_gd.bg_flags = &bg_flags;
1631         err = ext4_flex_group_add(sb, inode, &flex_gd);
1632 out:
1633         iput(inode);
1634         return err;
1635 } /* ext4_group_add */
1636
1637 /*
1638  * extend a group without checking assuming that checking has been done.
1639  */
1640 static int ext4_group_extend_no_check(struct super_block *sb,
1641                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1642 {
1643         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1644         handle_t *handle;
1645         int err = 0, err2;
1646
1647         /* We will update the superblock, one block bitmap, and
1648          * one group descriptor via ext4_group_add_blocks().
1649          */
1650         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1651         if (IS_ERR(handle)) {
1652                 err = PTR_ERR(handle);
1653                 ext4_warning(sb, "error %d on journal start", err);
1654                 return err;
1655         }
1656
1657         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1658         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1659         if (err) {
1660                 ext4_warning(sb, "error %d on journal write access", err);
1661                 goto errout;
1662         }
1663
1664         ext4_blocks_count_set(es, o_blocks_count + add);
1665         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1666         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1667                    o_blocks_count + add);
1668         /* We add the blocks to the bitmap and set the group need init bit */
1669         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1670         if (err)
1671                 goto errout;
1672         ext4_handle_dirty_super(handle, sb);
1673         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1674                    o_blocks_count + add);
1675 errout:
1676         err2 = ext4_journal_stop(handle);
1677         if (err2 && !err)
1678                 err = err2;
1679
1680         if (!err) {
1681                 if (test_opt(sb, DEBUG))
1682                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1683                                "blocks\n", ext4_blocks_count(es));
1684                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1685                                (char *)es, sizeof(struct ext4_super_block), 0);
1686         }
1687         return err;
1688 }
1689
1690 /*
1691  * Extend the filesystem to the new number of blocks specified.  This entry
1692  * point is only used to extend the current filesystem to the end of the last
1693  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1694  * for emergencies (because it has no dependencies on reserved blocks).
1695  *
1696  * If we _really_ wanted, we could use default values to call ext4_group_add()
1697  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1698  * GDT blocks are reserved to grow to the desired size.
1699  */
1700 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1701                       ext4_fsblk_t n_blocks_count)
1702 {
1703         ext4_fsblk_t o_blocks_count;
1704         ext4_grpblk_t last;
1705         ext4_grpblk_t add;
1706         struct buffer_head *bh;
1707         int err;
1708         ext4_group_t group;
1709
1710         o_blocks_count = ext4_blocks_count(es);
1711
1712         if (test_opt(sb, DEBUG))
1713                 ext4_msg(sb, KERN_DEBUG,
1714                          "extending last group from %llu to %llu blocks",
1715                          o_blocks_count, n_blocks_count);
1716
1717         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1718                 return 0;
1719
1720         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1721                 ext4_msg(sb, KERN_ERR,
1722                          "filesystem too large to resize to %llu blocks safely",
1723                          n_blocks_count);
1724                 if (sizeof(sector_t) < 8)
1725                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1726                 return -EINVAL;
1727         }
1728
1729         if (n_blocks_count < o_blocks_count) {
1730                 ext4_warning(sb, "can't shrink FS - resize aborted");
1731                 return -EINVAL;
1732         }
1733
1734         /* Handle the remaining blocks in the last group only. */
1735         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1736
1737         if (last == 0) {
1738                 ext4_warning(sb, "need to use ext2online to resize further");
1739                 return -EPERM;
1740         }
1741
1742         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1743
1744         if (o_blocks_count + add < o_blocks_count) {
1745                 ext4_warning(sb, "blocks_count overflow");
1746                 return -EINVAL;
1747         }
1748
1749         if (o_blocks_count + add > n_blocks_count)
1750                 add = n_blocks_count - o_blocks_count;
1751
1752         if (o_blocks_count + add < n_blocks_count)
1753                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1754                              o_blocks_count + add, add);
1755
1756         /* See if the device is actually as big as what was requested */
1757         bh = sb_bread(sb, o_blocks_count + add - 1);
1758         if (!bh) {
1759                 ext4_warning(sb, "can't read last block, resize aborted");
1760                 return -ENOSPC;
1761         }
1762         brelse(bh);
1763
1764         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1765         return err;
1766 } /* ext4_group_extend */
1767
1768
1769 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1770 {
1771         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1772 }
1773
1774 /*
1775  * Release the resize inode and drop the resize_inode feature if there
1776  * are no more reserved gdt blocks, and then convert the file system
1777  * to enable meta_bg
1778  */
1779 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1780 {
1781         handle_t *handle;
1782         struct ext4_sb_info *sbi = EXT4_SB(sb);
1783         struct ext4_super_block *es = sbi->s_es;
1784         struct ext4_inode_info *ei = EXT4_I(inode);
1785         ext4_fsblk_t nr;
1786         int i, ret, err = 0;
1787         int credits = 1;
1788
1789         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1790         if (inode) {
1791                 if (es->s_reserved_gdt_blocks) {
1792                         ext4_error(sb, "Unexpected non-zero "
1793                                    "s_reserved_gdt_blocks");
1794                         return -EPERM;
1795                 }
1796
1797                 /* Do a quick sanity check of the resize inode */
1798                 if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
1799                         goto invalid_resize_inode;
1800                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1801                         if (i == EXT4_DIND_BLOCK) {
1802                                 if (ei->i_data[i])
1803                                         continue;
1804                                 else
1805                                         goto invalid_resize_inode;
1806                         }
1807                         if (ei->i_data[i])
1808                                 goto invalid_resize_inode;
1809                 }
1810                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1811         }
1812
1813         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1814         if (IS_ERR(handle))
1815                 return PTR_ERR(handle);
1816
1817         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1818         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1819         if (err)
1820                 goto errout;
1821
1822         ext4_clear_feature_resize_inode(sb);
1823         ext4_set_feature_meta_bg(sb);
1824         sbi->s_es->s_first_meta_bg =
1825                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1826
1827         err = ext4_handle_dirty_super(handle, sb);
1828         if (err) {
1829                 ext4_std_error(sb, err);
1830                 goto errout;
1831         }
1832
1833         if (inode) {
1834                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1835                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1836                                  EXT4_FREE_BLOCKS_METADATA |
1837                                  EXT4_FREE_BLOCKS_FORGET);
1838                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1839                 inode->i_blocks = 0;
1840
1841                 err = ext4_mark_inode_dirty(handle, inode);
1842                 if (err)
1843                         ext4_std_error(sb, err);
1844         }
1845
1846 errout:
1847         ret = ext4_journal_stop(handle);
1848         if (!err)
1849                 err = ret;
1850         return ret;
1851
1852 invalid_resize_inode:
1853         ext4_error(sb, "corrupted/inconsistent resize inode");
1854         return -EINVAL;
1855 }
1856
1857 /*
1858  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1859  *
1860  * @sb: super block of the fs to be resized
1861  * @n_blocks_count: the number of blocks resides in the resized fs
1862  */
1863 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1864 {
1865         struct ext4_new_flex_group_data *flex_gd = NULL;
1866         struct ext4_sb_info *sbi = EXT4_SB(sb);
1867         struct ext4_super_block *es = sbi->s_es;
1868         struct buffer_head *bh;
1869         struct inode *resize_inode = NULL;
1870         ext4_grpblk_t add, offset;
1871         unsigned long n_desc_blocks;
1872         unsigned long o_desc_blocks;
1873         ext4_group_t o_group;
1874         ext4_group_t n_group;
1875         ext4_fsblk_t o_blocks_count;
1876         ext4_fsblk_t n_blocks_count_retry = 0;
1877         unsigned long last_update_time = 0;
1878         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1879         int meta_bg;
1880
1881         /* See if the device is actually as big as what was requested */
1882         bh = sb_bread(sb, n_blocks_count - 1);
1883         if (!bh) {
1884                 ext4_warning(sb, "can't read last block, resize aborted");
1885                 return -ENOSPC;
1886         }
1887         brelse(bh);
1888
1889 retry:
1890         o_blocks_count = ext4_blocks_count(es);
1891
1892         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1893                  "to %llu blocks", o_blocks_count, n_blocks_count);
1894
1895         if (n_blocks_count < o_blocks_count) {
1896                 /* On-line shrinking not supported */
1897                 ext4_warning(sb, "can't shrink FS - resize aborted");
1898                 return -EINVAL;
1899         }
1900
1901         if (n_blocks_count == o_blocks_count)
1902                 /* Nothing need to do */
1903                 return 0;
1904
1905         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1906         if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1907                 ext4_warning(sb, "resize would cause inodes_count overflow");
1908                 return -EINVAL;
1909         }
1910         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1911
1912         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1913         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1914
1915         meta_bg = ext4_has_feature_meta_bg(sb);
1916
1917         if (ext4_has_feature_resize_inode(sb)) {
1918                 if (meta_bg) {
1919                         ext4_error(sb, "resize_inode and meta_bg enabled "
1920                                    "simultaneously");
1921                         return -EINVAL;
1922                 }
1923                 if (n_desc_blocks > o_desc_blocks +
1924                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1925                         n_blocks_count_retry = n_blocks_count;
1926                         n_desc_blocks = o_desc_blocks +
1927                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1928                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1929                         n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
1930                         n_group--; /* set to last group number */
1931                 }
1932
1933                 if (!resize_inode)
1934                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1935                 if (IS_ERR(resize_inode)) {
1936                         ext4_warning(sb, "Error opening resize inode");
1937                         return PTR_ERR(resize_inode);
1938                 }
1939         }
1940
1941         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1942                 err = ext4_convert_meta_bg(sb, resize_inode);
1943                 if (err)
1944                         goto out;
1945                 if (resize_inode) {
1946                         iput(resize_inode);
1947                         resize_inode = NULL;
1948                 }
1949                 if (n_blocks_count_retry) {
1950                         n_blocks_count = n_blocks_count_retry;
1951                         n_blocks_count_retry = 0;
1952                         goto retry;
1953                 }
1954         }
1955
1956         /* extend the last group */
1957         if (n_group == o_group)
1958                 add = n_blocks_count - o_blocks_count;
1959         else
1960                 add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1961         if (add > 0) {
1962                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1963                 if (err)
1964                         goto out;
1965         }
1966
1967         if (ext4_blocks_count(es) == n_blocks_count)
1968                 goto out;
1969
1970         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1971         if (err)
1972                 return err;
1973
1974         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1975         if (err)
1976                 goto out;
1977
1978         flex_gd = alloc_flex_gd(flexbg_size);
1979         if (flex_gd == NULL) {
1980                 err = -ENOMEM;
1981                 goto out;
1982         }
1983
1984         /* Add flex groups. Note that a regular group is a
1985          * flex group with 1 group.
1986          */
1987         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1988                                               flexbg_size)) {
1989                 if (jiffies - last_update_time > HZ * 10) {
1990                         if (last_update_time)
1991                                 ext4_msg(sb, KERN_INFO,
1992                                          "resized to %llu blocks",
1993                                          ext4_blocks_count(es));
1994                         last_update_time = jiffies;
1995                 }
1996                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1997                         break;
1998                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1999                 if (unlikely(err))
2000                         break;
2001         }
2002
2003         if (!err && n_blocks_count_retry) {
2004                 n_blocks_count = n_blocks_count_retry;
2005                 n_blocks_count_retry = 0;
2006                 free_flex_gd(flex_gd);
2007                 flex_gd = NULL;
2008                 goto retry;
2009         }
2010
2011 out:
2012         if (flex_gd)
2013                 free_flex_gd(flex_gd);
2014         if (resize_inode != NULL)
2015                 iput(resize_inode);
2016         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2017         return err;
2018 }