fs/ext4/resize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/resize.c
   4  *
   5  * Support for resizing an ext4 filesystem while it is mounted.
   6  *
   7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17
  18 #include "ext4_jbd2.h"
  19
  20 struct ext4_rcu_ptr {
  21         struct rcu_head rcu;
  22         void *ptr;
  23 };
  24
  25 static void ext4_rcu_ptr_callback(struct rcu_head *head)
  26 {
  27         struct ext4_rcu_ptr *ptr;
  28
  29         ptr = container_of(head, struct ext4_rcu_ptr, rcu);
  30         kvfree(ptr->ptr);
  31         kfree(ptr);
  32 }
  33
  34 void ext4_kvfree_array_rcu(void *to_free)
  35 {
  36         struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
  37
  38         if (ptr) {
  39                 ptr->ptr = to_free;
  40                 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
  41                 return;
  42         }
  43         synchronize_rcu();
  44         kvfree(to_free);
  45 }
  46
  47 int ext4_resize_begin(struct super_block *sb)
  48 {
  49         struct ext4_sb_info *sbi = EXT4_SB(sb);
  50         int ret = 0;
  51
  52         if (!capable(CAP_SYS_RESOURCE))
  53                 return -EPERM;
  54
  55         /*
  56          * If we are not using the primary superblock/GDT copy don't resize,
  57          * because the user tools have no way of handling this.  Probably a
  58          * bad time to do it anyways.
  59          */
  60         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  61             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  62                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  63                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  64                 return -EPERM;
  65         }
  66
  67         /*
  68          * We are not allowed to do online-resizing on a filesystem mounted
  69          * with error, because it can destroy the filesystem easily.
  70          */
  71         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  72                 ext4_warning(sb, "There are errors in the filesystem, "
  73                              "so online resizing is not allowed");
  74                 return -EPERM;
  75         }
  76
  77         if (ext4_has_feature_sparse_super2(sb)) {
  78                 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
  79                 return -EOPNOTSUPP;
  80         }
  81
  82         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  83                                   &EXT4_SB(sb)->s_ext4_flags))
  84                 ret = -EBUSY;
  85
  86         return ret;
  87 }
  88
  89 void ext4_resize_end(struct super_block *sb)
  90 {
  91         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
  92         smp_mb__after_atomic();
  93 }
  94
  95 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  96                                              ext4_group_t group) {
  97         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  98                EXT4_DESC_PER_BLOCK_BITS(sb);
  99 }
 100
 101 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
 102                                              ext4_group_t group) {
 103         group = ext4_meta_bg_first_group(sb, group);
 104         return ext4_group_first_block_no(sb, group);
 105 }
 106
 107 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 108                                                 ext4_group_t group) {
 109         ext4_grpblk_t overhead;
 110         overhead = ext4_bg_num_gdb(sb, group);
 111         if (ext4_bg_has_super(sb, group))
 112                 overhead += 1 +
 113                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 114         return overhead;
 115 }
 116
 117 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
 118 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
 119
 120 static int verify_group_input(struct super_block *sb,
 121                               struct ext4_new_group_data *input)
 122 {
 123         struct ext4_sb_info *sbi = EXT4_SB(sb);
 124         struct ext4_super_block *es = sbi->s_es;
 125         ext4_fsblk_t start = ext4_blocks_count(es);
 126         ext4_fsblk_t end = start + input->blocks_count;
 127         ext4_group_t group = input->group;
 128         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 129         unsigned overhead;
 130         ext4_fsblk_t metaend;
 131         struct buffer_head *bh = NULL;
 132         ext4_grpblk_t free_blocks_count, offset;
 133         int err = -EINVAL;
 134
 135         if (group != sbi->s_groups_count) {
 136                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 137                              input->group, sbi->s_groups_count);
 138                 return -EINVAL;
 139         }
 140
 141         overhead = ext4_group_overhead_blocks(sb, group);
 142         metaend = start + overhead;
 143         input->free_clusters_count = free_blocks_count =
 144                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 145
 146         if (test_opt(sb, DEBUG))
 147                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 148                        "(%d free, %u reserved)\n",
 149                        ext4_bg_has_super(sb, input->group) ? "normal" :
 150                        "no-super", input->group, input->blocks_count,
 151                        free_blocks_count, input->reserved_blocks);
 152
 153         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 154         if (offset != 0)
 155                         ext4_warning(sb, "Last group not full");
 156         else if (input->reserved_blocks > input->blocks_count / 5)
 157                 ext4_warning(sb, "Reserved blocks too high (%u)",
 158                              input->reserved_blocks);
 159         else if (free_blocks_count < 0)
 160                 ext4_warning(sb, "Bad blocks count %u",
 161                              input->blocks_count);
 162         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 163                 err = PTR_ERR(bh);
 164                 bh = NULL;
 165                 ext4_warning(sb, "Cannot read last block (%llu)",
 166                              end - 1);
 167         } else if (outside(input->block_bitmap, start, end))
 168                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 169                              (unsigned long long)input->block_bitmap);
 170         else if (outside(input->inode_bitmap, start, end))
 171                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 172                              (unsigned long long)input->inode_bitmap);
 173         else if (outside(input->inode_table, start, end) ||
 174                  outside(itend - 1, start, end))
 175                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 176                              (unsigned long long)input->inode_table, itend - 1);
 177         else if (input->inode_bitmap == input->block_bitmap)
 178                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 179                              (unsigned long long)input->block_bitmap);
 180         else if (inside(input->block_bitmap, input->inode_table, itend))
 181                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 182                              "(%llu-%llu)",
 183                              (unsigned long long)input->block_bitmap,
 184                              (unsigned long long)input->inode_table, itend - 1);
 185         else if (inside(input->inode_bitmap, input->inode_table, itend))
 186                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 187                              "(%llu-%llu)",
 188                              (unsigned long long)input->inode_bitmap,
 189                              (unsigned long long)input->inode_table, itend - 1);
 190         else if (inside(input->block_bitmap, start, metaend))
 191                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 192                              (unsigned long long)input->block_bitmap,
 193                              start, metaend - 1);
 194         else if (inside(input->inode_bitmap, start, metaend))
 195                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 196                              (unsigned long long)input->inode_bitmap,
 197                              start, metaend - 1);
 198         else if (inside(input->inode_table, start, metaend) ||
 199                  inside(itend - 1, start, metaend))
 200                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 201                              "(%llu-%llu)",
 202                              (unsigned long long)input->inode_table,
 203                              itend - 1, start, metaend - 1);
 204         else
 205                 err = 0;
 206         brelse(bh);
 207
 208         return err;
 209 }
 210
 211 /*
 212  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 213  * group each time.
 214  */
 215 struct ext4_new_flex_group_data {
 216         struct ext4_new_group_data *groups;     /* new_group_data for groups
 217                                                    in the flex group */
 218         __u16 *bg_flags;                        /* block group flags of groups
 219                                                    in @groups */
 220         ext4_group_t count;                     /* number of groups in @groups
 221                                                  */
 222 };
 223
 224 /*
 225  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 226  * @flexbg_size.
 227  *
 228  * Returns NULL on failure otherwise address of the allocated structure.
 229  */
 230 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 231 {
 232         struct ext4_new_flex_group_data *flex_gd;
 233
 234         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 235         if (flex_gd == NULL)
 236                 goto out3;
 237
 238         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 239                 goto out2;
 240         flex_gd->count = flexbg_size;
 241
 242         flex_gd->groups = kmalloc_array(flexbg_size,
 243                                         sizeof(struct ext4_new_group_data),
 244                                         GFP_NOFS);
 245         if (flex_gd->groups == NULL)
 246                 goto out2;
 247
 248         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 249                                           GFP_NOFS);
 250         if (flex_gd->bg_flags == NULL)
 251                 goto out1;
 252
 253         return flex_gd;
 254
 255 out1:
 256         kfree(flex_gd->groups);
 257 out2:
 258         kfree(flex_gd);
 259 out3:
 260         return NULL;
 261 }
 262
 263 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 264 {
 265         kfree(flex_gd->bg_flags);
 266         kfree(flex_gd->groups);
 267         kfree(flex_gd);
 268 }
 269
 270 /*
 271  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 272  * and inode tables for a flex group.
 273  *
 274  * This function is used by 64bit-resize.  Note that this function allocates
 275  * group tables from the 1st group of groups contained by @flexgd, which may
 276  * be a partial of a flex group.
 277  *
 278  * @sb: super block of fs to which the groups belongs
 279  *
 280  * Returns 0 on a successful allocation of the metadata blocks in the
 281  * block group.
 282  */
 283 static int ext4_alloc_group_tables(struct super_block *sb,
 284                                 struct ext4_new_flex_group_data *flex_gd,
 285                                 int flexbg_size)
 286 {
 287         struct ext4_new_group_data *group_data = flex_gd->groups;
 288         ext4_fsblk_t start_blk;
 289         ext4_fsblk_t last_blk;
 290         ext4_group_t src_group;
 291         ext4_group_t bb_index = 0;
 292         ext4_group_t ib_index = 0;
 293         ext4_group_t it_index = 0;
 294         ext4_group_t group;
 295         ext4_group_t last_group;
 296         unsigned overhead;
 297         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 298         int i;
 299
 300         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 301
 302         src_group = group_data[0].group;
 303         last_group  = src_group + flex_gd->count - 1;
 304
 305         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 306                (last_group & ~(flexbg_size - 1))));
 307 next_group:
 308         group = group_data[0].group;
 309         if (src_group >= group_data[0].group + flex_gd->count)
 310                 return -ENOSPC;
 311         start_blk = ext4_group_first_block_no(sb, src_group);
 312         last_blk = start_blk + group_data[src_group - group].blocks_count;
 313
 314         overhead = ext4_group_overhead_blocks(sb, src_group);
 315
 316         start_blk += overhead;
 317
 318         /* We collect contiguous blocks as much as possible. */
 319         src_group++;
 320         for (; src_group <= last_group; src_group++) {
 321                 overhead = ext4_group_overhead_blocks(sb, src_group);
 322                 if (overhead == 0)
 323                         last_blk += group_data[src_group - group].blocks_count;
 324                 else
 325                         break;
 326         }
 327
 328         /* Allocate block bitmaps */
 329         for (; bb_index < flex_gd->count; bb_index++) {
 330                 if (start_blk >= last_blk)
 331                         goto next_group;
 332                 group_data[bb_index].block_bitmap = start_blk++;
 333                 group = ext4_get_group_number(sb, start_blk - 1);
 334                 group -= group_data[0].group;
 335                 group_data[group].mdata_blocks++;
 336                 flex_gd->bg_flags[group] &= uninit_mask;
 337         }
 338
 339         /* Allocate inode bitmaps */
 340         for (; ib_index < flex_gd->count; ib_index++) {
 341                 if (start_blk >= last_blk)
 342                         goto next_group;
 343                 group_data[ib_index].inode_bitmap = start_blk++;
 344                 group = ext4_get_group_number(sb, start_blk - 1);
 345                 group -= group_data[0].group;
 346                 group_data[group].mdata_blocks++;
 347                 flex_gd->bg_flags[group] &= uninit_mask;
 348         }
 349
 350         /* Allocate inode tables */
 351         for (; it_index < flex_gd->count; it_index++) {
 352                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 353                 ext4_fsblk_t next_group_start;
 354
 355                 if (start_blk + itb > last_blk)
 356                         goto next_group;
 357                 group_data[it_index].inode_table = start_blk;
 358                 group = ext4_get_group_number(sb, start_blk);
 359                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 360                 group -= group_data[0].group;
 361
 362                 if (start_blk + itb > next_group_start) {
 363                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 364                         overhead = start_blk + itb - next_group_start;
 365                         group_data[group + 1].mdata_blocks += overhead;
 366                         itb -= overhead;
 367                 }
 368
 369                 group_data[group].mdata_blocks += itb;
 370                 flex_gd->bg_flags[group] &= uninit_mask;
 371                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 372         }
 373
 374         /* Update free clusters count to exclude metadata blocks */
 375         for (i = 0; i < flex_gd->count; i++) {
 376                 group_data[i].free_clusters_count -=
 377                                 EXT4_NUM_B2C(EXT4_SB(sb),
 378                                              group_data[i].mdata_blocks);
 379         }
 380
 381         if (test_opt(sb, DEBUG)) {
 382                 int i;
 383                 group = group_data[0].group;
 384
 385                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 386                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 387                        flexbg_size);
 388
 389                 for (i = 0; i < flex_gd->count; i++) {
 390                         ext4_debug(
 391                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 392                                ext4_bg_has_super(sb, group + i) ? "normal" :
 393                                "no-super", group + i,
 394                                group_data[i].blocks_count,
 395                                group_data[i].free_clusters_count,
 396                                group_data[i].mdata_blocks);
 397                 }
 398         }
 399         return 0;
 400 }
 401
 402 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 403                                   ext4_fsblk_t blk)
 404 {
 405         struct buffer_head *bh;
 406         int err;
 407
 408         bh = sb_getblk(sb, blk);
 409         if (unlikely(!bh))
 410                 return ERR_PTR(-ENOMEM);
 411         BUFFER_TRACE(bh, "get_write_access");
 412         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
 413         if (err) {
 414                 brelse(bh);
 415                 bh = ERR_PTR(err);
 416         } else {
 417                 memset(bh->b_data, 0, sb->s_blocksize);
 418                 set_buffer_uptodate(bh);
 419         }
 420
 421         return bh;
 422 }
 423
 424 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 425 {
 426         return ext4_journal_ensure_credits_fn(handle, credits,
 427                 EXT4_MAX_TRANS_DATA, 0, 0);
 428 }
 429
 430 /*
 431  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 432  *
 433  * Helper function for ext4_setup_new_group_blocks() which set .
 434  *
 435  * @sb: super block
 436  * @handle: journal handle
 437  * @flex_gd: flex group data
 438  */
 439 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 440                         struct ext4_new_flex_group_data *flex_gd,
 441                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 442 {
 443         struct ext4_sb_info *sbi = EXT4_SB(sb);
 444         ext4_group_t count = last_cluster - first_cluster + 1;
 445         ext4_group_t count2;
 446
 447         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 448                    last_cluster);
 449         for (count2 = count; count > 0;
 450              count -= count2, first_cluster += count2) {
 451                 ext4_fsblk_t start;
 452                 struct buffer_head *bh;
 453                 ext4_group_t group;
 454                 int err;
 455
 456                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 457                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 458                 group -= flex_gd->groups[0].group;
 459
 460                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 461                 if (count2 > count)
 462                         count2 = count;
 463
 464                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 465                         BUG_ON(flex_gd->count > 1);
 466                         continue;
 467                 }
 468
 469                 err = ext4_resize_ensure_credits_batch(handle, 1);
 470                 if (err < 0)
 471                         return err;
 472
 473                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 474                 if (unlikely(!bh))
 475                         return -ENOMEM;
 476
 477                 BUFFER_TRACE(bh, "get_write_access");
 478                 err = ext4_journal_get_write_access(handle, sb, bh,
 479                                                     EXT4_JTR_NONE);
 480                 if (err) {
 481                         brelse(bh);
 482                         return err;
 483                 }
 484                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 485                            first_cluster, first_cluster - start, count2);
 486                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 487
 488                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 489                 brelse(bh);
 490                 if (unlikely(err))
 491                         return err;
 492         }
 493
 494         return 0;
 495 }
 496
 497 /*
 498  * Set up the block and inode bitmaps, and the inode table for the new groups.
 499  * This doesn't need to be part of the main transaction, since we are only
 500  * changing blocks outside the actual filesystem.  We still do journaling to
 501  * ensure the recovery is correct in case of a failure just after resize.
 502  * If any part of this fails, we simply abort the resize.
 503  *
 504  * setup_new_flex_group_blocks handles a flex group as follow:
 505  *  1. copy super block and GDT, and initialize group tables if necessary.
 506  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 507  *     super block and GDT.
 508  *  2. allocate group tables in block bitmaps, that is, set bits in block
 509  *     bitmap for blocks taken by group tables.
 510  */
 511 static int setup_new_flex_group_blocks(struct super_block *sb,
 512                                 struct ext4_new_flex_group_data *flex_gd)
 513 {
 514         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 515         ext4_fsblk_t start;
 516         ext4_fsblk_t block;
 517         struct ext4_sb_info *sbi = EXT4_SB(sb);
 518         struct ext4_super_block *es = sbi->s_es;
 519         struct ext4_new_group_data *group_data = flex_gd->groups;
 520         __u16 *bg_flags = flex_gd->bg_flags;
 521         handle_t *handle;
 522         ext4_group_t group, count;
 523         struct buffer_head *bh = NULL;
 524         int reserved_gdb, i, j, err = 0, err2;
 525         int meta_bg;
 526
 527         BUG_ON(!flex_gd->count || !group_data ||
 528                group_data[0].group != sbi->s_groups_count);
 529
 530         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 531         meta_bg = ext4_has_feature_meta_bg(sb);
 532
 533         /* This transaction may be extended/restarted along the way */
 534         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 535         if (IS_ERR(handle))
 536                 return PTR_ERR(handle);
 537
 538         group = group_data[0].group;
 539         for (i = 0; i < flex_gd->count; i++, group++) {
 540                 unsigned long gdblocks;
 541                 ext4_grpblk_t overhead;
 542
 543                 gdblocks = ext4_bg_num_gdb(sb, group);
 544                 start = ext4_group_first_block_no(sb, group);
 545
 546                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 547                         goto handle_itb;
 548
 549                 if (meta_bg == 1) {
 550                         ext4_group_t first_group;
 551                         first_group = ext4_meta_bg_first_group(sb, group);
 552                         if (first_group != group + 1 &&
 553                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 554                                 goto handle_itb;
 555                 }
 556
 557                 block = start + ext4_bg_has_super(sb, group);
 558                 /* Copy all of the GDT blocks into the backup in this group */
 559                 for (j = 0; j < gdblocks; j++, block++) {
 560                         struct buffer_head *gdb;
 561
 562                         ext4_debug("update backup group %#04llx\n", block);
 563                         err = ext4_resize_ensure_credits_batch(handle, 1);
 564                         if (err < 0)
 565                                 goto out;
 566
 567                         gdb = sb_getblk(sb, block);
 568                         if (unlikely(!gdb)) {
 569                                 err = -ENOMEM;
 570                                 goto out;
 571                         }
 572
 573                         BUFFER_TRACE(gdb, "get_write_access");
 574                         err = ext4_journal_get_write_access(handle, sb, gdb,
 575                                                             EXT4_JTR_NONE);
 576                         if (err) {
 577                                 brelse(gdb);
 578                                 goto out;
 579                         }
 580                         memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
 581                                 s_group_desc, j)->b_data, gdb->b_size);
 582                         set_buffer_uptodate(gdb);
 583
 584                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 585                         if (unlikely(err)) {
 586                                 brelse(gdb);
 587                                 goto out;
 588                         }
 589                         brelse(gdb);
 590                 }
 591
 592                 /* Zero out all of the reserved backup group descriptor
 593                  * table blocks
 594                  */
 595                 if (ext4_bg_has_super(sb, group)) {
 596                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 597                                         reserved_gdb, GFP_NOFS);
 598                         if (err)
 599                                 goto out;
 600                 }
 601
 602 handle_itb:
 603                 /* Initialize group tables of the grop @group */
 604                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 605                         goto handle_bb;
 606
 607                 /* Zero out all of the inode table blocks */
 608                 block = group_data[i].inode_table;
 609                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 610                            block, sbi->s_itb_per_group);
 611                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 612                                        GFP_NOFS);
 613                 if (err)
 614                         goto out;
 615
 616 handle_bb:
 617                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 618                         goto handle_ib;
 619
 620                 /* Initialize block bitmap of the @group */
 621                 block = group_data[i].block_bitmap;
 622                 err = ext4_resize_ensure_credits_batch(handle, 1);
 623                 if (err < 0)
 624                         goto out;
 625
 626                 bh = bclean(handle, sb, block);
 627                 if (IS_ERR(bh)) {
 628                         err = PTR_ERR(bh);
 629                         goto out;
 630                 }
 631                 overhead = ext4_group_overhead_blocks(sb, group);
 632                 if (overhead != 0) {
 633                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 634                                    start);
 635                         ext4_set_bits(bh->b_data, 0,
 636                                       EXT4_NUM_B2C(sbi, overhead));
 637                 }
 638                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 639                                      sb->s_blocksize * 8, bh->b_data);
 640                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 641                 brelse(bh);
 642                 if (err)
 643                         goto out;
 644
 645 handle_ib:
 646                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 647                         continue;
 648
 649                 /* Initialize inode bitmap of the @group */
 650                 block = group_data[i].inode_bitmap;
 651                 err = ext4_resize_ensure_credits_batch(handle, 1);
 652                 if (err < 0)
 653                         goto out;
 654                 /* Mark unused entries in inode bitmap used */
 655                 bh = bclean(handle, sb, block);
 656                 if (IS_ERR(bh)) {
 657                         err = PTR_ERR(bh);
 658                         goto out;
 659                 }
 660
 661                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 662                                      sb->s_blocksize * 8, bh->b_data);
 663                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 664                 brelse(bh);
 665                 if (err)
 666                         goto out;
 667         }
 668
 669         /* Mark group tables in block bitmap */
 670         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 671                 count = group_table_count[j];
 672                 start = (&group_data[0].block_bitmap)[j];
 673                 block = start;
 674                 for (i = 1; i < flex_gd->count; i++) {
 675                         block += group_table_count[j];
 676                         if (block == (&group_data[i].block_bitmap)[j]) {
 677                                 count += group_table_count[j];
 678                                 continue;
 679                         }
 680                         err = set_flexbg_block_bitmap(sb, handle,
 681                                                       flex_gd,
 682                                                       EXT4_B2C(sbi, start),
 683                                                       EXT4_B2C(sbi,
 684                                                                start + count
 685                                                                - 1));
 686                         if (err)
 687                                 goto out;
 688                         count = group_table_count[j];
 689                         start = (&group_data[i].block_bitmap)[j];
 690                         block = start;
 691                 }
 692
 693                 if (count) {
 694                         err = set_flexbg_block_bitmap(sb, handle,
 695                                                       flex_gd,
 696                                                       EXT4_B2C(sbi, start),
 697                                                       EXT4_B2C(sbi,
 698                                                                start + count
 699                                                                - 1));
 700                         if (err)
 701                                 goto out;
 702                 }
 703         }
 704
 705 out:
 706         err2 = ext4_journal_stop(handle);
 707         if (err2 && !err)
 708                 err = err2;
 709
 710         return err;
 711 }
 712
 713 /*
 714  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 715  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 716  * calling this for the first time.  In a sparse filesystem it will be the
 717  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 718  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 719  */
 720 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 721                                   unsigned *five, unsigned *seven)
 722 {
 723         unsigned *min = three;
 724         int mult = 3;
 725         unsigned ret;
 726
 727         if (!ext4_has_feature_sparse_super(sb)) {
 728                 ret = *min;
 729                 *min += 1;
 730                 return ret;
 731         }
 732
 733         if (*five < *min) {
 734                 min = five;
 735                 mult = 5;
 736         }
 737         if (*seven < *min) {
 738                 min = seven;
 739                 mult = 7;
 740         }
 741
 742         ret = *min;
 743         *min *= mult;
 744
 745         return ret;
 746 }
 747
 748 /*
 749  * Check that all of the backup GDT blocks are held in the primary GDT block.
 750  * It is assumed that they are stored in group order.  Returns the number of
 751  * groups in current filesystem that have BACKUPS, or -ve error code.
 752  */
 753 static int verify_reserved_gdb(struct super_block *sb,
 754                                ext4_group_t end,
 755                                struct buffer_head *primary)
 756 {
 757         const ext4_fsblk_t blk = primary->b_blocknr;
 758         unsigned three = 1;
 759         unsigned five = 5;
 760         unsigned seven = 7;
 761         unsigned grp;
 762         __le32 *p = (__le32 *)primary->b_data;
 763         int gdbackups = 0;
 764
 765         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 766                 if (le32_to_cpu(*p++) !=
 767                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 768                         ext4_warning(sb, "reserved GDT %llu"
 769                                      " missing grp %d (%llu)",
 770                                      blk, grp,
 771                                      grp *
 772                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 773                                      blk);
 774                         return -EINVAL;
 775                 }
 776                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 777                         return -EFBIG;
 778         }
 779
 780         return gdbackups;
 781 }
 782
 783 /*
 784  * Called when we need to bring a reserved group descriptor table block into
 785  * use from the resize inode.  The primary copy of the new GDT block currently
 786  * is an indirect block (under the double indirect block in the resize inode).
 787  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 788  * block, in group order.  Even though we know all the block numbers we need,
 789  * we check to ensure that the resize inode has actually reserved these blocks.
 790  *
 791  * Don't need to update the block bitmaps because the blocks are still in use.
 792  *
 793  * We get all of the error cases out of the way, so that we are sure to not
 794  * fail once we start modifying the data on disk, because JBD has no rollback.
 795  */
 796 static int add_new_gdb(handle_t *handle, struct inode *inode,
 797                        ext4_group_t group)
 798 {
 799         struct super_block *sb = inode->i_sb;
 800         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 801         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 802         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 803         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 804         struct buffer_head *dind = NULL;
 805         struct buffer_head *gdb_bh = NULL;
 806         int gdbackups;
 807         struct ext4_iloc iloc = { .bh = NULL };
 808         __le32 *data;
 809         int err;
 810
 811         if (test_opt(sb, DEBUG))
 812                 printk(KERN_DEBUG
 813                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 814                        gdb_num);
 815
 816         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 817         if (IS_ERR(gdb_bh))
 818                 return PTR_ERR(gdb_bh);
 819
 820         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 821         if (gdbackups < 0) {
 822                 err = gdbackups;
 823                 goto errout;
 824         }
 825
 826         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 827         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 828         if (IS_ERR(dind)) {
 829                 err = PTR_ERR(dind);
 830                 dind = NULL;
 831                 goto errout;
 832         }
 833
 834         data = (__le32 *)dind->b_data;
 835         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 836                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 837                              group, gdblock);
 838                 err = -EINVAL;
 839                 goto errout;
 840         }
 841
 842         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 843         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 844                                             EXT4_JTR_NONE);
 845         if (unlikely(err))
 846                 goto errout;
 847
 848         BUFFER_TRACE(gdb_bh, "get_write_access");
 849         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 850         if (unlikely(err))
 851                 goto errout;
 852
 853         BUFFER_TRACE(dind, "get_write_access");
 854         err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
 855         if (unlikely(err)) {
 856                 ext4_std_error(sb, err);
 857                 goto errout;
 858         }
 859
 860         /* ext4_reserve_inode_write() gets a reference on the iloc */
 861         err = ext4_reserve_inode_write(handle, inode, &iloc);
 862         if (unlikely(err))
 863                 goto errout;
 864
 865         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 866                                 GFP_KERNEL);
 867         if (!n_group_desc) {
 868                 err = -ENOMEM;
 869                 ext4_warning(sb, "not enough memory for %lu groups",
 870                              gdb_num + 1);
 871                 goto errout;
 872         }
 873
 874         /*
 875          * Finally, we have all of the possible failures behind us...
 876          *
 877          * Remove new GDT block from inode double-indirect block and clear out
 878          * the new GDT block for use (which also "frees" the backup GDT blocks
 879          * from the reserved inode).  We don't need to change the bitmaps for
 880          * these blocks, because they are marked as in-use from being in the
 881          * reserved inode, and will become GDT blocks (primary and backup).
 882          */
 883         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 884         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 885         if (unlikely(err)) {
 886                 ext4_std_error(sb, err);
 887                 goto errout;
 888         }
 889         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 890                            (9 - EXT4_SB(sb)->s_cluster_bits);
 891         ext4_mark_iloc_dirty(handle, inode, &iloc);
 892         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 893         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 894         if (unlikely(err)) {
 895                 ext4_std_error(sb, err);
 896                 iloc.bh = NULL;
 897                 goto errout;
 898         }
 899         brelse(dind);
 900
 901         rcu_read_lock();
 902         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 903         memcpy(n_group_desc, o_group_desc,
 904                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 905         rcu_read_unlock();
 906         n_group_desc[gdb_num] = gdb_bh;
 907         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 908         EXT4_SB(sb)->s_gdb_count++;
 909         ext4_kvfree_array_rcu(o_group_desc);
 910
 911         lock_buffer(EXT4_SB(sb)->s_sbh);
 912         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 913         ext4_superblock_csum_set(sb);
 914         unlock_buffer(EXT4_SB(sb)->s_sbh);
 915         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 916         if (err)
 917                 ext4_std_error(sb, err);
 918         return err;
 919 errout:
 920         kvfree(n_group_desc);
 921         brelse(iloc.bh);
 922         brelse(dind);
 923         brelse(gdb_bh);
 924
 925         ext4_debug("leaving with error %d\n", err);
 926         return err;
 927 }
 928
 929 /*
 930  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 931  */
 932 static int add_new_gdb_meta_bg(struct super_block *sb,
 933                                handle_t *handle, ext4_group_t group) {
 934         ext4_fsblk_t gdblock;
 935         struct buffer_head *gdb_bh;
 936         struct buffer_head **o_group_desc, **n_group_desc;
 937         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 938         int err;
 939
 940         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 941                    ext4_bg_has_super(sb, group);
 942         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 943         if (IS_ERR(gdb_bh))
 944                 return PTR_ERR(gdb_bh);
 945         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 946                                 GFP_KERNEL);
 947         if (!n_group_desc) {
 948                 brelse(gdb_bh);
 949                 err = -ENOMEM;
 950                 ext4_warning(sb, "not enough memory for %lu groups",
 951                              gdb_num + 1);
 952                 return err;
 953         }
 954
 955         rcu_read_lock();
 956         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 957         memcpy(n_group_desc, o_group_desc,
 958                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 959         rcu_read_unlock();
 960         n_group_desc[gdb_num] = gdb_bh;
 961
 962         BUFFER_TRACE(gdb_bh, "get_write_access");
 963         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 964         if (err) {
 965                 kvfree(n_group_desc);
 966                 brelse(gdb_bh);
 967                 return err;
 968         }
 969
 970         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 971         EXT4_SB(sb)->s_gdb_count++;
 972         ext4_kvfree_array_rcu(o_group_desc);
 973         return err;
 974 }
 975
 976 /*
 977  * Called when we are adding a new group which has a backup copy of each of
 978  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 979  * We need to add these reserved backup GDT blocks to the resize inode, so
 980  * that they are kept for future resizing and not allocated to files.
 981  *
 982  * Each reserved backup GDT block will go into a different indirect block.
 983  * The indirect blocks are actually the primary reserved GDT blocks,
 984  * so we know in advance what their block numbers are.  We only get the
 985  * double-indirect block to verify it is pointing to the primary reserved
 986  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 987  * backup GDT blocks are stored in their reserved primary GDT block.
 988  */
 989 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 990                               ext4_group_t group)
 991 {
 992         struct super_block *sb = inode->i_sb;
 993         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 994         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 995         struct buffer_head **primary;
 996         struct buffer_head *dind;
 997         struct ext4_iloc iloc;
 998         ext4_fsblk_t blk;
 999         __le32 *data, *end;
1000         int gdbackups = 0;
1001         int res, i;
1002         int err;
1003
1004         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1005         if (!primary)
1006                 return -ENOMEM;
1007
1008         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1009         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1010         if (IS_ERR(dind)) {
1011                 err = PTR_ERR(dind);
1012                 dind = NULL;
1013                 goto exit_free;
1014         }
1015
1016         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1017         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1018                                          EXT4_ADDR_PER_BLOCK(sb));
1019         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1020
1021         /* Get each reserved primary GDT block and verify it holds backups */
1022         for (res = 0; res < reserved_gdb; res++, blk++) {
1023                 if (le32_to_cpu(*data) != blk) {
1024                         ext4_warning(sb, "reserved block %llu"
1025                                      " not at offset %ld",
1026                                      blk,
1027                                      (long)(data - (__le32 *)dind->b_data));
1028                         err = -EINVAL;
1029                         goto exit_bh;
1030                 }
1031                 primary[res] = ext4_sb_bread(sb, blk, 0);
1032                 if (IS_ERR(primary[res])) {
1033                         err = PTR_ERR(primary[res]);
1034                         primary[res] = NULL;
1035                         goto exit_bh;
1036                 }
1037                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1038                 if (gdbackups < 0) {
1039                         brelse(primary[res]);
1040                         err = gdbackups;
1041                         goto exit_bh;
1042                 }
1043                 if (++data >= end)
1044                         data = (__le32 *)dind->b_data;
1045         }
1046
1047         for (i = 0; i < reserved_gdb; i++) {
1048                 BUFFER_TRACE(primary[i], "get_write_access");
1049                 if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1050                                                          EXT4_JTR_NONE)))
1051                         goto exit_bh;
1052         }
1053
1054         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1055                 goto exit_bh;
1056
1057         /*
1058          * Finally we can add each of the reserved backup GDT blocks from
1059          * the new group to its reserved primary GDT block.
1060          */
1061         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1062         for (i = 0; i < reserved_gdb; i++) {
1063                 int err2;
1064                 data = (__le32 *)primary[i]->b_data;
1065                 /* printk("reserving backup %lu[%u] = %lu\n",
1066                        primary[i]->b_blocknr, gdbackups,
1067                        blk + primary[i]->b_blocknr); */
1068                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1069                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1070                 if (!err)
1071                         err = err2;
1072         }
1073
1074         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1075         ext4_mark_iloc_dirty(handle, inode, &iloc);
1076
1077 exit_bh:
1078         while (--res >= 0)
1079                 brelse(primary[res]);
1080         brelse(dind);
1081
1082 exit_free:
1083         kfree(primary);
1084
1085         return err;
1086 }
1087
1088 /*
1089  * Update the backup copies of the ext4 metadata.  These don't need to be part
1090  * of the main resize transaction, because e2fsck will re-write them if there
1091  * is a problem (basically only OOM will cause a problem).  However, we
1092  * _should_ update the backups if possible, in case the primary gets trashed
1093  * for some reason and we need to run e2fsck from a backup superblock.  The
1094  * important part is that the new block and inode counts are in the backup
1095  * superblocks, and the location of the new group metadata in the GDT backups.
1096  *
1097  * We do not need take the s_resize_lock for this, because these
1098  * blocks are not otherwise touched by the filesystem code when it is
1099  * mounted.  We don't need to worry about last changing from
1100  * sbi->s_groups_count, because the worst that can happen is that we
1101  * do not copy the full number of backups at this time.  The resize
1102  * which changed s_groups_count will backup again.
1103  */
1104 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1105                            int size, int meta_bg)
1106 {
1107         struct ext4_sb_info *sbi = EXT4_SB(sb);
1108         ext4_group_t last;
1109         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1110         unsigned three = 1;
1111         unsigned five = 5;
1112         unsigned seven = 7;
1113         ext4_group_t group = 0;
1114         int rest = sb->s_blocksize - size;
1115         handle_t *handle;
1116         int err = 0, err2;
1117
1118         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1119         if (IS_ERR(handle)) {
1120                 group = 1;
1121                 err = PTR_ERR(handle);
1122                 goto exit_err;
1123         }
1124
1125         if (meta_bg == 0) {
1126                 group = ext4_list_backups(sb, &three, &five, &seven);
1127                 last = sbi->s_groups_count;
1128         } else {
1129                 group = ext4_get_group_number(sb, blk_off) + 1;
1130                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1131         }
1132
1133         while (group < sbi->s_groups_count) {
1134                 struct buffer_head *bh;
1135                 ext4_fsblk_t backup_block;
1136
1137                 /* Out of journal space, and can't get more - abort - so sad */
1138                 err = ext4_resize_ensure_credits_batch(handle, 1);
1139                 if (err < 0)
1140                         break;
1141
1142                 if (meta_bg == 0)
1143                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1144                 else
1145                         backup_block = (ext4_group_first_block_no(sb, group) +
1146                                         ext4_bg_has_super(sb, group));
1147
1148                 bh = sb_getblk(sb, backup_block);
1149                 if (unlikely(!bh)) {
1150                         err = -ENOMEM;
1151                         break;
1152                 }
1153                 ext4_debug("update metadata backup %llu(+%llu)\n",
1154                            backup_block, backup_block -
1155                            ext4_group_first_block_no(sb, group));
1156                 BUFFER_TRACE(bh, "get_write_access");
1157                 if ((err = ext4_journal_get_write_access(handle, sb, bh,
1158                                                          EXT4_JTR_NONE)))
1159                         break;
1160                 lock_buffer(bh);
1161                 memcpy(bh->b_data, data, size);
1162                 if (rest)
1163                         memset(bh->b_data + size, 0, rest);
1164                 set_buffer_uptodate(bh);
1165                 unlock_buffer(bh);
1166                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1167                 if (unlikely(err))
1168                         ext4_std_error(sb, err);
1169                 brelse(bh);
1170
1171                 if (meta_bg == 0)
1172                         group = ext4_list_backups(sb, &three, &five, &seven);
1173                 else if (group == last)
1174                         break;
1175                 else
1176                         group = last;
1177         }
1178         if ((err2 = ext4_journal_stop(handle)) && !err)
1179                 err = err2;
1180
1181         /*
1182          * Ugh! Need to have e2fsck write the backup copies.  It is too
1183          * late to revert the resize, we shouldn't fail just because of
1184          * the backup copies (they are only needed in case of corruption).
1185          *
1186          * However, if we got here we have a journal problem too, so we
1187          * can't really start a transaction to mark the superblock.
1188          * Chicken out and just set the flag on the hope it will be written
1189          * to disk, and if not - we will simply wait until next fsck.
1190          */
1191 exit_err:
1192         if (err) {
1193                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1194                              "forcing fsck on next reboot", group, err);
1195                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1196                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1197                 mark_buffer_dirty(sbi->s_sbh);
1198         }
1199 }
1200
1201 /*
1202  * ext4_add_new_descs() adds @count group descriptor of groups
1203  * starting at @group
1204  *
1205  * @handle: journal handle
1206  * @sb: super block
1207  * @group: the group no. of the first group desc to be added
1208  * @resize_inode: the resize inode
1209  * @count: number of group descriptors to be added
1210  */
1211 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1212                               ext4_group_t group, struct inode *resize_inode,
1213                               ext4_group_t count)
1214 {
1215         struct ext4_sb_info *sbi = EXT4_SB(sb);
1216         struct ext4_super_block *es = sbi->s_es;
1217         struct buffer_head *gdb_bh;
1218         int i, gdb_off, gdb_num, err = 0;
1219         int meta_bg;
1220
1221         meta_bg = ext4_has_feature_meta_bg(sb);
1222         for (i = 0; i < count; i++, group++) {
1223                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1224                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1225
1226                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1227                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1228
1229                 /*
1230                  * We will only either add reserved group blocks to a backup group
1231                  * or remove reserved blocks for the first group in a new group block.
1232                  * Doing both would be mean more complex code, and sane people don't
1233                  * use non-sparse filesystems anymore.  This is already checked above.
1234                  */
1235                 if (gdb_off) {
1236                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1237                                                      gdb_num);
1238                         BUFFER_TRACE(gdb_bh, "get_write_access");
1239                         err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1240                                                             EXT4_JTR_NONE);
1241
1242                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1243                                 err = reserve_backup_gdb(handle, resize_inode, group);
1244                 } else if (meta_bg != 0) {
1245                         err = add_new_gdb_meta_bg(sb, handle, group);
1246                 } else {
1247                         err = add_new_gdb(handle, resize_inode, group);
1248                 }
1249                 if (err)
1250                         break;
1251         }
1252         return err;
1253 }
1254
1255 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1256 {
1257         struct buffer_head *bh = sb_getblk(sb, block);
1258         if (unlikely(!bh))
1259                 return NULL;
1260         if (!bh_uptodate_or_lock(bh)) {
1261                 if (ext4_read_bh(bh, 0, NULL) < 0) {
1262                         brelse(bh);
1263                         return NULL;
1264                 }
1265         }
1266
1267         return bh;
1268 }
1269
1270 static int ext4_set_bitmap_checksums(struct super_block *sb,
1271                                      ext4_group_t group,
1272                                      struct ext4_group_desc *gdp,
1273                                      struct ext4_new_group_data *group_data)
1274 {
1275         struct buffer_head *bh;
1276
1277         if (!ext4_has_metadata_csum(sb))
1278                 return 0;
1279
1280         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1281         if (!bh)
1282                 return -EIO;
1283         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1284                                    EXT4_INODES_PER_GROUP(sb) / 8);
1285         brelse(bh);
1286
1287         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1288         if (!bh)
1289                 return -EIO;
1290         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1291         brelse(bh);
1292
1293         return 0;
1294 }
1295
1296 /*
1297  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1298  */
1299 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1300                                 struct ext4_new_flex_group_data *flex_gd)
1301 {
1302         struct ext4_new_group_data      *group_data = flex_gd->groups;
1303         struct ext4_group_desc          *gdp;
1304         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1305         struct buffer_head              *gdb_bh;
1306         ext4_group_t                    group;
1307         __u16                           *bg_flags = flex_gd->bg_flags;
1308         int                             i, gdb_off, gdb_num, err = 0;
1309
1310
1311         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1312                 group = group_data->group;
1313
1314                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1315                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1316
1317                 /*
1318                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1319                  */
1320                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1321                 /* Update group descriptor block for new group */
1322                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1323                                                  gdb_off * EXT4_DESC_SIZE(sb));
1324
1325                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1326                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1327                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1328                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1329                 if (err) {
1330                         ext4_std_error(sb, err);
1331                         break;
1332                 }
1333
1334                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1335                 ext4_free_group_clusters_set(sb, gdp,
1336                                              group_data->free_clusters_count);
1337                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1338                 if (ext4_has_group_desc_csum(sb))
1339                         ext4_itable_unused_set(sb, gdp,
1340                                                EXT4_INODES_PER_GROUP(sb));
1341                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1342                 ext4_group_desc_csum_set(sb, group, gdp);
1343
1344                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1345                 if (unlikely(err)) {
1346                         ext4_std_error(sb, err);
1347                         break;
1348                 }
1349
1350                 /*
1351                  * We can allocate memory for mb_alloc based on the new group
1352                  * descriptor
1353                  */
1354                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1355                 if (err)
1356                         break;
1357         }
1358         return err;
1359 }
1360
1361 /*
1362  * ext4_update_super() updates the super block so that the newly added
1363  * groups can be seen by the filesystem.
1364  *
1365  * @sb: super block
1366  * @flex_gd: new added groups
1367  */
1368 static void ext4_update_super(struct super_block *sb,
1369                              struct ext4_new_flex_group_data *flex_gd)
1370 {
1371         ext4_fsblk_t blocks_count = 0;
1372         ext4_fsblk_t free_blocks = 0;
1373         ext4_fsblk_t reserved_blocks = 0;
1374         struct ext4_new_group_data *group_data = flex_gd->groups;
1375         struct ext4_sb_info *sbi = EXT4_SB(sb);
1376         struct ext4_super_block *es = sbi->s_es;
1377         int i;
1378
1379         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1380         /*
1381          * Make the new blocks and inodes valid next.  We do this before
1382          * increasing the group count so that once the group is enabled,
1383          * all of its blocks and inodes are already valid.
1384          *
1385          * We always allocate group-by-group, then block-by-block or
1386          * inode-by-inode within a group, so enabling these
1387          * blocks/inodes before the group is live won't actually let us
1388          * allocate the new space yet.
1389          */
1390         for (i = 0; i < flex_gd->count; i++) {
1391                 blocks_count += group_data[i].blocks_count;
1392                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1393         }
1394
1395         reserved_blocks = ext4_r_blocks_count(es) * 100;
1396         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1397         reserved_blocks *= blocks_count;
1398         do_div(reserved_blocks, 100);
1399
1400         lock_buffer(sbi->s_sbh);
1401         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1402         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1403         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1404                      flex_gd->count);
1405         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1406                      flex_gd->count);
1407
1408         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1409         /*
1410          * We need to protect s_groups_count against other CPUs seeing
1411          * inconsistent state in the superblock.
1412          *
1413          * The precise rules we use are:
1414          *
1415          * * Writers must perform a smp_wmb() after updating all
1416          *   dependent data and before modifying the groups count
1417          *
1418          * * Readers must perform an smp_rmb() after reading the groups
1419          *   count and before reading any dependent data.
1420          *
1421          * NB. These rules can be relaxed when checking the group count
1422          * while freeing data, as we can only allocate from a block
1423          * group after serialising against the group count, and we can
1424          * only then free after serialising in turn against that
1425          * allocation.
1426          */
1427         smp_wmb();
1428
1429         /* Update the global fs size fields */
1430         sbi->s_groups_count += flex_gd->count;
1431         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1432                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1433
1434         /* Update the reserved block counts only once the new group is
1435          * active. */
1436         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1437                                 reserved_blocks);
1438         ext4_superblock_csum_set(sb);
1439         unlock_buffer(sbi->s_sbh);
1440
1441         /* Update the free space counts */
1442         percpu_counter_add(&sbi->s_freeclusters_counter,
1443                            EXT4_NUM_B2C(sbi, free_blocks));
1444         percpu_counter_add(&sbi->s_freeinodes_counter,
1445                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1446
1447         ext4_debug("free blocks count %llu",
1448                    percpu_counter_read(&sbi->s_freeclusters_counter));
1449         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1450                 ext4_group_t flex_group;
1451                 struct flex_groups *fg;
1452
1453                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1454                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1455                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1456                              &fg->free_clusters);
1457                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1458                            &fg->free_inodes);
1459         }
1460
1461         /*
1462          * Update the fs overhead information
1463          */
1464         ext4_calculate_overhead(sb);
1465
1466         if (test_opt(sb, DEBUG))
1467                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1468                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1469                        blocks_count, free_blocks, reserved_blocks);
1470 }
1471
1472 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1473  * _before_ we start modifying the filesystem, because we cannot abort the
1474  * transaction and not have it write the data to disk.
1475  */
1476 static int ext4_flex_group_add(struct super_block *sb,
1477                                struct inode *resize_inode,
1478                                struct ext4_new_flex_group_data *flex_gd)
1479 {
1480         struct ext4_sb_info *sbi = EXT4_SB(sb);
1481         struct ext4_super_block *es = sbi->s_es;
1482         ext4_fsblk_t o_blocks_count;
1483         ext4_grpblk_t last;
1484         ext4_group_t group;
1485         handle_t *handle;
1486         unsigned reserved_gdb;
1487         int err = 0, err2 = 0, credit;
1488
1489         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1490
1491         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1492         o_blocks_count = ext4_blocks_count(es);
1493         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1494         BUG_ON(last);
1495
1496         err = setup_new_flex_group_blocks(sb, flex_gd);
1497         if (err)
1498                 goto exit;
1499         /*
1500          * We will always be modifying at least the superblock and  GDT
1501          * blocks.  If we are adding a group past the last current GDT block,
1502          * we will also modify the inode and the dindirect block.  If we
1503          * are adding a group with superblock/GDT backups  we will also
1504          * modify each of the reserved GDT dindirect blocks.
1505          */
1506         credit = 3;     /* sb, resize inode, resize inode dindirect */
1507         /* GDT blocks */
1508         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1509         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1510         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1511         if (IS_ERR(handle)) {
1512                 err = PTR_ERR(handle);
1513                 goto exit;
1514         }
1515
1516         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1517         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1518                                             EXT4_JTR_NONE);
1519         if (err)
1520                 goto exit_journal;
1521
1522         group = flex_gd->groups[0].group;
1523         BUG_ON(group != sbi->s_groups_count);
1524         err = ext4_add_new_descs(handle, sb, group,
1525                                 resize_inode, flex_gd->count);
1526         if (err)
1527                 goto exit_journal;
1528
1529         err = ext4_setup_new_descs(handle, sb, flex_gd);
1530         if (err)
1531                 goto exit_journal;
1532
1533         ext4_update_super(sb, flex_gd);
1534
1535         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1536
1537 exit_journal:
1538         err2 = ext4_journal_stop(handle);
1539         if (!err)
1540                 err = err2;
1541
1542         if (!err) {
1543                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1544                 int gdb_num_end = ((group + flex_gd->count - 1) /
1545                                    EXT4_DESC_PER_BLOCK(sb));
1546                 int meta_bg = ext4_has_feature_meta_bg(sb);
1547                 sector_t old_gdb = 0;
1548
1549                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1550                                sizeof(struct ext4_super_block), 0);
1551                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1552                         struct buffer_head *gdb_bh;
1553
1554                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1555                                                      gdb_num);
1556                         if (old_gdb == gdb_bh->b_blocknr)
1557                                 continue;
1558                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1559                                        gdb_bh->b_size, meta_bg);
1560                         old_gdb = gdb_bh->b_blocknr;
1561                 }
1562         }
1563 exit:
1564         return err;
1565 }
1566
1567 static int ext4_setup_next_flex_gd(struct super_block *sb,
1568                                     struct ext4_new_flex_group_data *flex_gd,
1569                                     ext4_fsblk_t n_blocks_count,
1570                                     unsigned long flexbg_size)
1571 {
1572         struct ext4_sb_info *sbi = EXT4_SB(sb);
1573         struct ext4_super_block *es = sbi->s_es;
1574         struct ext4_new_group_data *group_data = flex_gd->groups;
1575         ext4_fsblk_t o_blocks_count;
1576         ext4_group_t n_group;
1577         ext4_group_t group;
1578         ext4_group_t last_group;
1579         ext4_grpblk_t last;
1580         ext4_grpblk_t clusters_per_group;
1581         unsigned long i;
1582
1583         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1584
1585         o_blocks_count = ext4_blocks_count(es);
1586
1587         if (o_blocks_count == n_blocks_count)
1588                 return 0;
1589
1590         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1591         BUG_ON(last);
1592         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1593
1594         last_group = group | (flexbg_size - 1);
1595         if (last_group > n_group)
1596                 last_group = n_group;
1597
1598         flex_gd->count = last_group - group + 1;
1599
1600         for (i = 0; i < flex_gd->count; i++) {
1601                 int overhead;
1602
1603                 group_data[i].group = group + i;
1604                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1605                 overhead = ext4_group_overhead_blocks(sb, group + i);
1606                 group_data[i].mdata_blocks = overhead;
1607                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1608                 if (ext4_has_group_desc_csum(sb)) {
1609                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1610                                                EXT4_BG_INODE_UNINIT;
1611                         if (!test_opt(sb, INIT_INODE_TABLE))
1612                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1613                 } else
1614                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1615         }
1616
1617         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1618                 /* We need to initialize block bitmap of last group. */
1619                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1620
1621         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1622                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1623                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1624                                                        last - 1;
1625         }
1626
1627         return 1;
1628 }
1629
1630 /* Add group descriptor data to an existing or new group descriptor block.
1631  * Ensure we handle all possible error conditions _before_ we start modifying
1632  * the filesystem, because we cannot abort the transaction and not have it
1633  * write the data to disk.
1634  *
1635  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1636  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1637  *
1638  * We only need to hold the superblock lock while we are actually adding
1639  * in the new group's counts to the superblock.  Prior to that we have
1640  * not really "added" the group at all.  We re-check that we are still
1641  * adding in the last group in case things have changed since verifying.
1642  */
1643 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1644 {
1645         struct ext4_new_flex_group_data flex_gd;
1646         struct ext4_sb_info *sbi = EXT4_SB(sb);
1647         struct ext4_super_block *es = sbi->s_es;
1648         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1649                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1650         struct inode *inode = NULL;
1651         int gdb_off;
1652         int err;
1653         __u16 bg_flags = 0;
1654
1655         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1656
1657         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1658                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1659                 return -EPERM;
1660         }
1661
1662         if (ext4_blocks_count(es) + input->blocks_count <
1663             ext4_blocks_count(es)) {
1664                 ext4_warning(sb, "blocks_count overflow");
1665                 return -EINVAL;
1666         }
1667
1668         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1669             le32_to_cpu(es->s_inodes_count)) {
1670                 ext4_warning(sb, "inodes_count overflow");
1671                 return -EINVAL;
1672         }
1673
1674         if (reserved_gdb || gdb_off == 0) {
1675                 if (!ext4_has_feature_resize_inode(sb) ||
1676                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1677                         ext4_warning(sb,
1678                                      "No reserved GDT blocks, can't resize");
1679                         return -EPERM;
1680                 }
1681                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1682                 if (IS_ERR(inode)) {
1683                         ext4_warning(sb, "Error opening resize inode");
1684                         return PTR_ERR(inode);
1685                 }
1686         }
1687
1688
1689         err = verify_group_input(sb, input);
1690         if (err)
1691                 goto out;
1692
1693         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1694         if (err)
1695                 goto out;
1696
1697         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1698         if (err)
1699                 goto out;
1700
1701         flex_gd.count = 1;
1702         flex_gd.groups = input;
1703         flex_gd.bg_flags = &bg_flags;
1704         err = ext4_flex_group_add(sb, inode, &flex_gd);
1705 out:
1706         iput(inode);
1707         return err;
1708 } /* ext4_group_add */
1709
1710 /*
1711  * extend a group without checking assuming that checking has been done.
1712  */
1713 static int ext4_group_extend_no_check(struct super_block *sb,
1714                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1715 {
1716         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1717         handle_t *handle;
1718         int err = 0, err2;
1719
1720         /* We will update the superblock, one block bitmap, and
1721          * one group descriptor via ext4_group_add_blocks().
1722          */
1723         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1724         if (IS_ERR(handle)) {
1725                 err = PTR_ERR(handle);
1726                 ext4_warning(sb, "error %d on journal start", err);
1727                 return err;
1728         }
1729
1730         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1731         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1732                                             EXT4_JTR_NONE);
1733         if (err) {
1734                 ext4_warning(sb, "error %d on journal write access", err);
1735                 goto errout;
1736         }
1737
1738         lock_buffer(EXT4_SB(sb)->s_sbh);
1739         ext4_blocks_count_set(es, o_blocks_count + add);
1740         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1741         ext4_superblock_csum_set(sb);
1742         unlock_buffer(EXT4_SB(sb)->s_sbh);
1743         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1744                    o_blocks_count + add);
1745         /* We add the blocks to the bitmap and set the group need init bit */
1746         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1747         if (err)
1748                 goto errout;
1749         ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1750         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1751                    o_blocks_count + add);
1752 errout:
1753         err2 = ext4_journal_stop(handle);
1754         if (err2 && !err)
1755                 err = err2;
1756
1757         if (!err) {
1758                 if (test_opt(sb, DEBUG))
1759                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1760                                "blocks\n", ext4_blocks_count(es));
1761                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1762                                (char *)es, sizeof(struct ext4_super_block), 0);
1763         }
1764         return err;
1765 }
1766
1767 /*
1768  * Extend the filesystem to the new number of blocks specified.  This entry
1769  * point is only used to extend the current filesystem to the end of the last
1770  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1771  * for emergencies (because it has no dependencies on reserved blocks).
1772  *
1773  * If we _really_ wanted, we could use default values to call ext4_group_add()
1774  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1775  * GDT blocks are reserved to grow to the desired size.
1776  */
1777 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1778                       ext4_fsblk_t n_blocks_count)
1779 {
1780         ext4_fsblk_t o_blocks_count;
1781         ext4_grpblk_t last;
1782         ext4_grpblk_t add;
1783         struct buffer_head *bh;
1784         int err;
1785         ext4_group_t group;
1786
1787         o_blocks_count = ext4_blocks_count(es);
1788
1789         if (test_opt(sb, DEBUG))
1790                 ext4_msg(sb, KERN_DEBUG,
1791                          "extending last group from %llu to %llu blocks",
1792                          o_blocks_count, n_blocks_count);
1793
1794         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1795                 return 0;
1796
1797         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1798                 ext4_msg(sb, KERN_ERR,
1799                          "filesystem too large to resize to %llu blocks safely",
1800                          n_blocks_count);
1801                 return -EINVAL;
1802         }
1803
1804         if (n_blocks_count < o_blocks_count) {
1805                 ext4_warning(sb, "can't shrink FS - resize aborted");
1806                 return -EINVAL;
1807         }
1808
1809         /* Handle the remaining blocks in the last group only. */
1810         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1811
1812         if (last == 0) {
1813                 ext4_warning(sb, "need to use ext2online to resize further");
1814                 return -EPERM;
1815         }
1816
1817         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1818
1819         if (o_blocks_count + add < o_blocks_count) {
1820                 ext4_warning(sb, "blocks_count overflow");
1821                 return -EINVAL;
1822         }
1823
1824         if (o_blocks_count + add > n_blocks_count)
1825                 add = n_blocks_count - o_blocks_count;
1826
1827         if (o_blocks_count + add < n_blocks_count)
1828                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1829                              o_blocks_count + add, add);
1830
1831         /* See if the device is actually as big as what was requested */
1832         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1833         if (IS_ERR(bh)) {
1834                 ext4_warning(sb, "can't read last block, resize aborted");
1835                 return -ENOSPC;
1836         }
1837         brelse(bh);
1838
1839         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1840         return err;
1841 } /* ext4_group_extend */
1842
1843
1844 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1845 {
1846         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1847 }
1848
1849 /*
1850  * Release the resize inode and drop the resize_inode feature if there
1851  * are no more reserved gdt blocks, and then convert the file system
1852  * to enable meta_bg
1853  */
1854 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1855 {
1856         handle_t *handle;
1857         struct ext4_sb_info *sbi = EXT4_SB(sb);
1858         struct ext4_super_block *es = sbi->s_es;
1859         struct ext4_inode_info *ei = EXT4_I(inode);
1860         ext4_fsblk_t nr;
1861         int i, ret, err = 0;
1862         int credits = 1;
1863
1864         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1865         if (inode) {
1866                 if (es->s_reserved_gdt_blocks) {
1867                         ext4_error(sb, "Unexpected non-zero "
1868                                    "s_reserved_gdt_blocks");
1869                         return -EPERM;
1870                 }
1871
1872                 /* Do a quick sanity check of the resize inode */
1873                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1874                                              (9 - sbi->s_cluster_bits)))
1875                         goto invalid_resize_inode;
1876                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1877                         if (i == EXT4_DIND_BLOCK) {
1878                                 if (ei->i_data[i])
1879                                         continue;
1880                                 else
1881                                         goto invalid_resize_inode;
1882                         }
1883                         if (ei->i_data[i])
1884                                 goto invalid_resize_inode;
1885                 }
1886                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1887         }
1888
1889         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1890         if (IS_ERR(handle))
1891                 return PTR_ERR(handle);
1892
1893         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1894         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1895                                             EXT4_JTR_NONE);
1896         if (err)
1897                 goto errout;
1898
1899         lock_buffer(sbi->s_sbh);
1900         ext4_clear_feature_resize_inode(sb);
1901         ext4_set_feature_meta_bg(sb);
1902         sbi->s_es->s_first_meta_bg =
1903                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1904         ext4_superblock_csum_set(sb);
1905         unlock_buffer(sbi->s_sbh);
1906
1907         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1908         if (err) {
1909                 ext4_std_error(sb, err);
1910                 goto errout;
1911         }
1912
1913         if (inode) {
1914                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1915                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1916                                  EXT4_FREE_BLOCKS_METADATA |
1917                                  EXT4_FREE_BLOCKS_FORGET);
1918                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1919                 inode->i_blocks = 0;
1920
1921                 err = ext4_mark_inode_dirty(handle, inode);
1922                 if (err)
1923                         ext4_std_error(sb, err);
1924         }
1925
1926 errout:
1927         ret = ext4_journal_stop(handle);
1928         if (!err)
1929                 err = ret;
1930         return ret;
1931
1932 invalid_resize_inode:
1933         ext4_error(sb, "corrupted/inconsistent resize inode");
1934         return -EINVAL;
1935 }
1936
1937 /*
1938  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1939  *
1940  * @sb: super block of the fs to be resized
1941  * @n_blocks_count: the number of blocks resides in the resized fs
1942  */
1943 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1944 {
1945         struct ext4_new_flex_group_data *flex_gd = NULL;
1946         struct ext4_sb_info *sbi = EXT4_SB(sb);
1947         struct ext4_super_block *es = sbi->s_es;
1948         struct buffer_head *bh;
1949         struct inode *resize_inode = NULL;
1950         ext4_grpblk_t add, offset;
1951         unsigned long n_desc_blocks;
1952         unsigned long o_desc_blocks;
1953         ext4_group_t o_group;
1954         ext4_group_t n_group;
1955         ext4_fsblk_t o_blocks_count;
1956         ext4_fsblk_t n_blocks_count_retry = 0;
1957         unsigned long last_update_time = 0;
1958         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1959         int meta_bg;
1960
1961         /* See if the device is actually as big as what was requested */
1962         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
1963         if (IS_ERR(bh)) {
1964                 ext4_warning(sb, "can't read last block, resize aborted");
1965                 return -ENOSPC;
1966         }
1967         brelse(bh);
1968
1969 retry:
1970         o_blocks_count = ext4_blocks_count(es);
1971
1972         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1973                  "to %llu blocks", o_blocks_count, n_blocks_count);
1974
1975         if (n_blocks_count < o_blocks_count) {
1976                 /* On-line shrinking not supported */
1977                 ext4_warning(sb, "can't shrink FS - resize aborted");
1978                 return -EINVAL;
1979         }
1980
1981         if (n_blocks_count == o_blocks_count)
1982                 /* Nothing need to do */
1983                 return 0;
1984
1985         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1986         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1987                 ext4_warning(sb, "resize would cause inodes_count overflow");
1988                 return -EINVAL;
1989         }
1990         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1991
1992         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1993         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1994
1995         meta_bg = ext4_has_feature_meta_bg(sb);
1996
1997         if (ext4_has_feature_resize_inode(sb)) {
1998                 if (meta_bg) {
1999                         ext4_error(sb, "resize_inode and meta_bg enabled "
2000                                    "simultaneously");
2001                         return -EINVAL;
2002                 }
2003                 if (n_desc_blocks > o_desc_blocks +
2004                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
2005                         n_blocks_count_retry = n_blocks_count;
2006                         n_desc_blocks = o_desc_blocks +
2007                                 le16_to_cpu(es->s_reserved_gdt_blocks);
2008                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2009                         n_blocks_count = (ext4_fsblk_t)n_group *
2010                                 EXT4_BLOCKS_PER_GROUP(sb) +
2011                                 le32_to_cpu(es->s_first_data_block);
2012                         n_group--; /* set to last group number */
2013                 }
2014
2015                 if (!resize_inode)
2016                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2017                                                  EXT4_IGET_SPECIAL);
2018                 if (IS_ERR(resize_inode)) {
2019                         ext4_warning(sb, "Error opening resize inode");
2020                         return PTR_ERR(resize_inode);
2021                 }
2022         }
2023
2024         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2025                 err = ext4_convert_meta_bg(sb, resize_inode);
2026                 if (err)
2027                         goto out;
2028                 if (resize_inode) {
2029                         iput(resize_inode);
2030                         resize_inode = NULL;
2031                 }
2032                 if (n_blocks_count_retry) {
2033                         n_blocks_count = n_blocks_count_retry;
2034                         n_blocks_count_retry = 0;
2035                         goto retry;
2036                 }
2037         }
2038
2039         /*
2040          * Make sure the last group has enough space so that it's
2041          * guaranteed to have enough space for all metadata blocks
2042          * that it might need to hold.  (We might not need to store
2043          * the inode table blocks in the last block group, but there
2044          * will be cases where this might be needed.)
2045          */
2046         if ((ext4_group_first_block_no(sb, n_group) +
2047              ext4_group_overhead_blocks(sb, n_group) + 2 +
2048              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2049                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2050                 n_group--;
2051                 n_blocks_count_retry = 0;
2052                 if (resize_inode) {
2053                         iput(resize_inode);
2054                         resize_inode = NULL;
2055                 }
2056                 goto retry;
2057         }
2058
2059         /* extend the last group */
2060         if (n_group == o_group)
2061                 add = n_blocks_count - o_blocks_count;
2062         else
2063                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2064         if (add > 0) {
2065                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2066                 if (err)
2067                         goto out;
2068         }
2069
2070         if (ext4_blocks_count(es) == n_blocks_count)
2071                 goto out;
2072
2073         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2074         if (err)
2075                 goto out;
2076
2077         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2078         if (err)
2079                 goto out;
2080
2081         flex_gd = alloc_flex_gd(flexbg_size);
2082         if (flex_gd == NULL) {
2083                 err = -ENOMEM;
2084                 goto out;
2085         }
2086
2087         /* Add flex groups. Note that a regular group is a
2088          * flex group with 1 group.
2089          */
2090         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2091                                               flexbg_size)) {
2092                 if (jiffies - last_update_time > HZ * 10) {
2093                         if (last_update_time)
2094                                 ext4_msg(sb, KERN_INFO,
2095                                          "resized to %llu blocks",
2096                                          ext4_blocks_count(es));
2097                         last_update_time = jiffies;
2098                 }
2099                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2100                         break;
2101                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2102                 if (unlikely(err))
2103                         break;
2104         }
2105
2106         if (!err && n_blocks_count_retry) {
2107                 n_blocks_count = n_blocks_count_retry;
2108                 n_blocks_count_retry = 0;
2109                 free_flex_gd(flex_gd);
2110                 flex_gd = NULL;
2111                 if (resize_inode) {
2112                         iput(resize_inode);
2113                         resize_inode = NULL;
2114                 }
2115                 goto retry;
2116         }
2117
2118 out:
2119         if (flex_gd)
2120                 free_flex_gd(flex_gd);
2121         if (resize_inode != NULL)
2122                 iput(resize_inode);
2123         if (err)
2124                 ext4_warning(sb, "error (%d) occurred during "
2125                              "file system resize", err);
2126         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2127                  ext4_blocks_count(es));
2128         return err;
2129 }