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 #include <linux/jiffies.h>
  18
  19 #include "ext4_jbd2.h"
  20
  21 struct ext4_rcu_ptr {
  22         struct rcu_head rcu;
  23         void *ptr;
  24 };
  25
  26 static void ext4_rcu_ptr_callback(struct rcu_head *head)
  27 {
  28         struct ext4_rcu_ptr *ptr;
  29
  30         ptr = container_of(head, struct ext4_rcu_ptr, rcu);
  31         kvfree(ptr->ptr);
  32         kfree(ptr);
  33 }
  34
  35 void ext4_kvfree_array_rcu(void *to_free)
  36 {
  37         struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
  38
  39         if (ptr) {
  40                 ptr->ptr = to_free;
  41                 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
  42                 return;
  43         }
  44         synchronize_rcu();
  45         kvfree(to_free);
  46 }
  47
  48 int ext4_resize_begin(struct super_block *sb)
  49 {
  50         struct ext4_sb_info *sbi = EXT4_SB(sb);
  51         int ret = 0;
  52
  53         if (!capable(CAP_SYS_RESOURCE))
  54                 return -EPERM;
  55
  56         /*
  57          * If the reserved GDT blocks is non-zero, the resize_inode feature
  58          * should always be set.
  59          */
  60         if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
  61             !ext4_has_feature_resize_inode(sb)) {
  62                 ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
  63                 return -EFSCORRUPTED;
  64         }
  65
  66         /*
  67          * If we are not using the primary superblock/GDT copy don't resize,
  68          * because the user tools have no way of handling this.  Probably a
  69          * bad time to do it anyways.
  70          */
  71         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  72             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  73                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  74                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  75                 return -EPERM;
  76         }
  77
  78         /*
  79          * We are not allowed to do online-resizing on a filesystem mounted
  80          * with error, because it can destroy the filesystem easily.
  81          */
  82         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  83                 ext4_warning(sb, "There are errors in the filesystem, "
  84                              "so online resizing is not allowed");
  85                 return -EPERM;
  86         }
  87
  88         if (ext4_has_feature_sparse_super2(sb)) {
  89                 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
  90                 return -EOPNOTSUPP;
  91         }
  92
  93         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  94                                   &EXT4_SB(sb)->s_ext4_flags))
  95                 ret = -EBUSY;
  96
  97         return ret;
  98 }
  99
 100 void ext4_resize_end(struct super_block *sb)
 101 {
 102         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
 103         smp_mb__after_atomic();
 104 }
 105
 106 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
 107                                              ext4_group_t group) {
 108         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
 109                EXT4_DESC_PER_BLOCK_BITS(sb);
 110 }
 111
 112 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
 113                                              ext4_group_t group) {
 114         group = ext4_meta_bg_first_group(sb, group);
 115         return ext4_group_first_block_no(sb, group);
 116 }
 117
 118 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 119                                                 ext4_group_t group) {
 120         ext4_grpblk_t overhead;
 121         overhead = ext4_bg_num_gdb(sb, group);
 122         if (ext4_bg_has_super(sb, group))
 123                 overhead += 1 +
 124                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 125         return overhead;
 126 }
 127
 128 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
 129 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
 130
 131 static int verify_group_input(struct super_block *sb,
 132                               struct ext4_new_group_data *input)
 133 {
 134         struct ext4_sb_info *sbi = EXT4_SB(sb);
 135         struct ext4_super_block *es = sbi->s_es;
 136         ext4_fsblk_t start = ext4_blocks_count(es);
 137         ext4_fsblk_t end = start + input->blocks_count;
 138         ext4_group_t group = input->group;
 139         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 140         unsigned overhead;
 141         ext4_fsblk_t metaend;
 142         struct buffer_head *bh = NULL;
 143         ext4_grpblk_t free_blocks_count, offset;
 144         int err = -EINVAL;
 145
 146         if (group != sbi->s_groups_count) {
 147                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 148                              input->group, sbi->s_groups_count);
 149                 return -EINVAL;
 150         }
 151
 152         overhead = ext4_group_overhead_blocks(sb, group);
 153         metaend = start + overhead;
 154         input->free_clusters_count = free_blocks_count =
 155                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 156
 157         if (test_opt(sb, DEBUG))
 158                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 159                        "(%d free, %u reserved)\n",
 160                        ext4_bg_has_super(sb, input->group) ? "normal" :
 161                        "no-super", input->group, input->blocks_count,
 162                        free_blocks_count, input->reserved_blocks);
 163
 164         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 165         if (offset != 0)
 166                         ext4_warning(sb, "Last group not full");
 167         else if (input->reserved_blocks > input->blocks_count / 5)
 168                 ext4_warning(sb, "Reserved blocks too high (%u)",
 169                              input->reserved_blocks);
 170         else if (free_blocks_count < 0)
 171                 ext4_warning(sb, "Bad blocks count %u",
 172                              input->blocks_count);
 173         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 174                 err = PTR_ERR(bh);
 175                 bh = NULL;
 176                 ext4_warning(sb, "Cannot read last block (%llu)",
 177                              end - 1);
 178         } else if (outside(input->block_bitmap, start, end))
 179                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 180                              (unsigned long long)input->block_bitmap);
 181         else if (outside(input->inode_bitmap, start, end))
 182                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 183                              (unsigned long long)input->inode_bitmap);
 184         else if (outside(input->inode_table, start, end) ||
 185                  outside(itend - 1, start, end))
 186                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 187                              (unsigned long long)input->inode_table, itend - 1);
 188         else if (input->inode_bitmap == input->block_bitmap)
 189                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 190                              (unsigned long long)input->block_bitmap);
 191         else if (inside(input->block_bitmap, input->inode_table, itend))
 192                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 193                              "(%llu-%llu)",
 194                              (unsigned long long)input->block_bitmap,
 195                              (unsigned long long)input->inode_table, itend - 1);
 196         else if (inside(input->inode_bitmap, input->inode_table, itend))
 197                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 198                              "(%llu-%llu)",
 199                              (unsigned long long)input->inode_bitmap,
 200                              (unsigned long long)input->inode_table, itend - 1);
 201         else if (inside(input->block_bitmap, start, metaend))
 202                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 203                              (unsigned long long)input->block_bitmap,
 204                              start, metaend - 1);
 205         else if (inside(input->inode_bitmap, start, metaend))
 206                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 207                              (unsigned long long)input->inode_bitmap,
 208                              start, metaend - 1);
 209         else if (inside(input->inode_table, start, metaend) ||
 210                  inside(itend - 1, start, metaend))
 211                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 212                              "(%llu-%llu)",
 213                              (unsigned long long)input->inode_table,
 214                              itend - 1, start, metaend - 1);
 215         else
 216                 err = 0;
 217         brelse(bh);
 218
 219         return err;
 220 }
 221
 222 /*
 223  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 224  * group each time.
 225  */
 226 struct ext4_new_flex_group_data {
 227         struct ext4_new_group_data *groups;     /* new_group_data for groups
 228                                                    in the flex group */
 229         __u16 *bg_flags;                        /* block group flags of groups
 230                                                    in @groups */
 231         ext4_group_t count;                     /* number of groups in @groups
 232                                                  */
 233 };
 234
 235 /*
 236  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 237  * @flexbg_size.
 238  *
 239  * Returns NULL on failure otherwise address of the allocated structure.
 240  */
 241 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 242 {
 243         struct ext4_new_flex_group_data *flex_gd;
 244
 245         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 246         if (flex_gd == NULL)
 247                 goto out3;
 248
 249         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 250                 goto out2;
 251         flex_gd->count = flexbg_size;
 252
 253         flex_gd->groups = kmalloc_array(flexbg_size,
 254                                         sizeof(struct ext4_new_group_data),
 255                                         GFP_NOFS);
 256         if (flex_gd->groups == NULL)
 257                 goto out2;
 258
 259         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 260                                           GFP_NOFS);
 261         if (flex_gd->bg_flags == NULL)
 262                 goto out1;
 263
 264         return flex_gd;
 265
 266 out1:
 267         kfree(flex_gd->groups);
 268 out2:
 269         kfree(flex_gd);
 270 out3:
 271         return NULL;
 272 }
 273
 274 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 275 {
 276         kfree(flex_gd->bg_flags);
 277         kfree(flex_gd->groups);
 278         kfree(flex_gd);
 279 }
 280
 281 /*
 282  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 283  * and inode tables for a flex group.
 284  *
 285  * This function is used by 64bit-resize.  Note that this function allocates
 286  * group tables from the 1st group of groups contained by @flexgd, which may
 287  * be a partial of a flex group.
 288  *
 289  * @sb: super block of fs to which the groups belongs
 290  *
 291  * Returns 0 on a successful allocation of the metadata blocks in the
 292  * block group.
 293  */
 294 static int ext4_alloc_group_tables(struct super_block *sb,
 295                                 struct ext4_new_flex_group_data *flex_gd,
 296                                 int flexbg_size)
 297 {
 298         struct ext4_new_group_data *group_data = flex_gd->groups;
 299         ext4_fsblk_t start_blk;
 300         ext4_fsblk_t last_blk;
 301         ext4_group_t src_group;
 302         ext4_group_t bb_index = 0;
 303         ext4_group_t ib_index = 0;
 304         ext4_group_t it_index = 0;
 305         ext4_group_t group;
 306         ext4_group_t last_group;
 307         unsigned overhead;
 308         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 309         int i;
 310
 311         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 312
 313         src_group = group_data[0].group;
 314         last_group  = src_group + flex_gd->count - 1;
 315
 316         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 317                (last_group & ~(flexbg_size - 1))));
 318 next_group:
 319         group = group_data[0].group;
 320         if (src_group >= group_data[0].group + flex_gd->count)
 321                 return -ENOSPC;
 322         start_blk = ext4_group_first_block_no(sb, src_group);
 323         last_blk = start_blk + group_data[src_group - group].blocks_count;
 324
 325         overhead = ext4_group_overhead_blocks(sb, src_group);
 326
 327         start_blk += overhead;
 328
 329         /* We collect contiguous blocks as much as possible. */
 330         src_group++;
 331         for (; src_group <= last_group; src_group++) {
 332                 overhead = ext4_group_overhead_blocks(sb, src_group);
 333                 if (overhead == 0)
 334                         last_blk += group_data[src_group - group].blocks_count;
 335                 else
 336                         break;
 337         }
 338
 339         /* Allocate block bitmaps */
 340         for (; bb_index < flex_gd->count; bb_index++) {
 341                 if (start_blk >= last_blk)
 342                         goto next_group;
 343                 group_data[bb_index].block_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 bitmaps */
 351         for (; ib_index < flex_gd->count; ib_index++) {
 352                 if (start_blk >= last_blk)
 353                         goto next_group;
 354                 group_data[ib_index].inode_bitmap = start_blk++;
 355                 group = ext4_get_group_number(sb, start_blk - 1);
 356                 group -= group_data[0].group;
 357                 group_data[group].mdata_blocks++;
 358                 flex_gd->bg_flags[group] &= uninit_mask;
 359         }
 360
 361         /* Allocate inode tables */
 362         for (; it_index < flex_gd->count; it_index++) {
 363                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 364                 ext4_fsblk_t next_group_start;
 365
 366                 if (start_blk + itb > last_blk)
 367                         goto next_group;
 368                 group_data[it_index].inode_table = start_blk;
 369                 group = ext4_get_group_number(sb, start_blk);
 370                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 371                 group -= group_data[0].group;
 372
 373                 if (start_blk + itb > next_group_start) {
 374                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 375                         overhead = start_blk + itb - next_group_start;
 376                         group_data[group + 1].mdata_blocks += overhead;
 377                         itb -= overhead;
 378                 }
 379
 380                 group_data[group].mdata_blocks += itb;
 381                 flex_gd->bg_flags[group] &= uninit_mask;
 382                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 383         }
 384
 385         /* Update free clusters count to exclude metadata blocks */
 386         for (i = 0; i < flex_gd->count; i++) {
 387                 group_data[i].free_clusters_count -=
 388                                 EXT4_NUM_B2C(EXT4_SB(sb),
 389                                              group_data[i].mdata_blocks);
 390         }
 391
 392         if (test_opt(sb, DEBUG)) {
 393                 int i;
 394                 group = group_data[0].group;
 395
 396                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 397                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 398                        flexbg_size);
 399
 400                 for (i = 0; i < flex_gd->count; i++) {
 401                         ext4_debug(
 402                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 403                                ext4_bg_has_super(sb, group + i) ? "normal" :
 404                                "no-super", group + i,
 405                                group_data[i].blocks_count,
 406                                group_data[i].free_clusters_count,
 407                                group_data[i].mdata_blocks);
 408                 }
 409         }
 410         return 0;
 411 }
 412
 413 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 414                                   ext4_fsblk_t blk)
 415 {
 416         struct buffer_head *bh;
 417         int err;
 418
 419         bh = sb_getblk(sb, blk);
 420         if (unlikely(!bh))
 421                 return ERR_PTR(-ENOMEM);
 422         BUFFER_TRACE(bh, "get_write_access");
 423         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
 424         if (err) {
 425                 brelse(bh);
 426                 bh = ERR_PTR(err);
 427         } else {
 428                 memset(bh->b_data, 0, sb->s_blocksize);
 429                 set_buffer_uptodate(bh);
 430         }
 431
 432         return bh;
 433 }
 434
 435 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 436 {
 437         return ext4_journal_ensure_credits_fn(handle, credits,
 438                 EXT4_MAX_TRANS_DATA, 0, 0);
 439 }
 440
 441 /*
 442  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 443  *
 444  * Helper function for ext4_setup_new_group_blocks() which set .
 445  *
 446  * @sb: super block
 447  * @handle: journal handle
 448  * @flex_gd: flex group data
 449  */
 450 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 451                         struct ext4_new_flex_group_data *flex_gd,
 452                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 453 {
 454         struct ext4_sb_info *sbi = EXT4_SB(sb);
 455         ext4_group_t count = last_cluster - first_cluster + 1;
 456         ext4_group_t count2;
 457
 458         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 459                    last_cluster);
 460         for (count2 = count; count > 0;
 461              count -= count2, first_cluster += count2) {
 462                 ext4_fsblk_t start;
 463                 struct buffer_head *bh;
 464                 ext4_group_t group;
 465                 int err;
 466
 467                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 468                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 469                 group -= flex_gd->groups[0].group;
 470
 471                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 472                 if (count2 > count)
 473                         count2 = count;
 474
 475                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 476                         BUG_ON(flex_gd->count > 1);
 477                         continue;
 478                 }
 479
 480                 err = ext4_resize_ensure_credits_batch(handle, 1);
 481                 if (err < 0)
 482                         return err;
 483
 484                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 485                 if (unlikely(!bh))
 486                         return -ENOMEM;
 487
 488                 BUFFER_TRACE(bh, "get_write_access");
 489                 err = ext4_journal_get_write_access(handle, sb, bh,
 490                                                     EXT4_JTR_NONE);
 491                 if (err) {
 492                         brelse(bh);
 493                         return err;
 494                 }
 495                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 496                            first_cluster, first_cluster - start, count2);
 497                 mb_set_bits(bh->b_data, first_cluster - start, count2);
 498
 499                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 500                 brelse(bh);
 501                 if (unlikely(err))
 502                         return err;
 503         }
 504
 505         return 0;
 506 }
 507
 508 /*
 509  * Set up the block and inode bitmaps, and the inode table for the new groups.
 510  * This doesn't need to be part of the main transaction, since we are only
 511  * changing blocks outside the actual filesystem.  We still do journaling to
 512  * ensure the recovery is correct in case of a failure just after resize.
 513  * If any part of this fails, we simply abort the resize.
 514  *
 515  * setup_new_flex_group_blocks handles a flex group as follow:
 516  *  1. copy super block and GDT, and initialize group tables if necessary.
 517  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 518  *     super block and GDT.
 519  *  2. allocate group tables in block bitmaps, that is, set bits in block
 520  *     bitmap for blocks taken by group tables.
 521  */
 522 static int setup_new_flex_group_blocks(struct super_block *sb,
 523                                 struct ext4_new_flex_group_data *flex_gd)
 524 {
 525         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 526         ext4_fsblk_t start;
 527         ext4_fsblk_t block;
 528         struct ext4_sb_info *sbi = EXT4_SB(sb);
 529         struct ext4_super_block *es = sbi->s_es;
 530         struct ext4_new_group_data *group_data = flex_gd->groups;
 531         __u16 *bg_flags = flex_gd->bg_flags;
 532         handle_t *handle;
 533         ext4_group_t group, count;
 534         struct buffer_head *bh = NULL;
 535         int reserved_gdb, i, j, err = 0, err2;
 536         int meta_bg;
 537
 538         BUG_ON(!flex_gd->count || !group_data ||
 539                group_data[0].group != sbi->s_groups_count);
 540
 541         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 542         meta_bg = ext4_has_feature_meta_bg(sb);
 543
 544         /* This transaction may be extended/restarted along the way */
 545         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 546         if (IS_ERR(handle))
 547                 return PTR_ERR(handle);
 548
 549         group = group_data[0].group;
 550         for (i = 0; i < flex_gd->count; i++, group++) {
 551                 unsigned long gdblocks;
 552                 ext4_grpblk_t overhead;
 553
 554                 gdblocks = ext4_bg_num_gdb(sb, group);
 555                 start = ext4_group_first_block_no(sb, group);
 556
 557                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 558                         goto handle_itb;
 559
 560                 if (meta_bg == 1) {
 561                         ext4_group_t first_group;
 562                         first_group = ext4_meta_bg_first_group(sb, group);
 563                         if (first_group != group + 1 &&
 564                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 565                                 goto handle_itb;
 566                 }
 567
 568                 block = start + ext4_bg_has_super(sb, group);
 569                 /* Copy all of the GDT blocks into the backup in this group */
 570                 for (j = 0; j < gdblocks; j++, block++) {
 571                         struct buffer_head *gdb;
 572
 573                         ext4_debug("update backup group %#04llx\n", block);
 574                         err = ext4_resize_ensure_credits_batch(handle, 1);
 575                         if (err < 0)
 576                                 goto out;
 577
 578                         gdb = sb_getblk(sb, block);
 579                         if (unlikely(!gdb)) {
 580                                 err = -ENOMEM;
 581                                 goto out;
 582                         }
 583
 584                         BUFFER_TRACE(gdb, "get_write_access");
 585                         err = ext4_journal_get_write_access(handle, sb, gdb,
 586                                                             EXT4_JTR_NONE);
 587                         if (err) {
 588                                 brelse(gdb);
 589                                 goto out;
 590                         }
 591                         memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
 592                                 s_group_desc, j)->b_data, gdb->b_size);
 593                         set_buffer_uptodate(gdb);
 594
 595                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 596                         if (unlikely(err)) {
 597                                 brelse(gdb);
 598                                 goto out;
 599                         }
 600                         brelse(gdb);
 601                 }
 602
 603                 /* Zero out all of the reserved backup group descriptor
 604                  * table blocks
 605                  */
 606                 if (ext4_bg_has_super(sb, group)) {
 607                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 608                                         reserved_gdb, GFP_NOFS);
 609                         if (err)
 610                                 goto out;
 611                 }
 612
 613 handle_itb:
 614                 /* Initialize group tables of the grop @group */
 615                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 616                         goto handle_bb;
 617
 618                 /* Zero out all of the inode table blocks */
 619                 block = group_data[i].inode_table;
 620                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 621                            block, sbi->s_itb_per_group);
 622                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 623                                        GFP_NOFS);
 624                 if (err)
 625                         goto out;
 626
 627 handle_bb:
 628                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 629                         goto handle_ib;
 630
 631                 /* Initialize block bitmap of the @group */
 632                 block = group_data[i].block_bitmap;
 633                 err = ext4_resize_ensure_credits_batch(handle, 1);
 634                 if (err < 0)
 635                         goto out;
 636
 637                 bh = bclean(handle, sb, block);
 638                 if (IS_ERR(bh)) {
 639                         err = PTR_ERR(bh);
 640                         goto out;
 641                 }
 642                 overhead = ext4_group_overhead_blocks(sb, group);
 643                 if (overhead != 0) {
 644                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 645                                    start);
 646                         mb_set_bits(bh->b_data, 0,
 647                                       EXT4_NUM_B2C(sbi, overhead));
 648                 }
 649                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 650                                      sb->s_blocksize * 8, bh->b_data);
 651                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 652                 brelse(bh);
 653                 if (err)
 654                         goto out;
 655
 656 handle_ib:
 657                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 658                         continue;
 659
 660                 /* Initialize inode bitmap of the @group */
 661                 block = group_data[i].inode_bitmap;
 662                 err = ext4_resize_ensure_credits_batch(handle, 1);
 663                 if (err < 0)
 664                         goto out;
 665                 /* Mark unused entries in inode bitmap used */
 666                 bh = bclean(handle, sb, block);
 667                 if (IS_ERR(bh)) {
 668                         err = PTR_ERR(bh);
 669                         goto out;
 670                 }
 671
 672                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 673                                      sb->s_blocksize * 8, bh->b_data);
 674                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 675                 brelse(bh);
 676                 if (err)
 677                         goto out;
 678         }
 679
 680         /* Mark group tables in block bitmap */
 681         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 682                 count = group_table_count[j];
 683                 start = (&group_data[0].block_bitmap)[j];
 684                 block = start;
 685                 for (i = 1; i < flex_gd->count; i++) {
 686                         block += group_table_count[j];
 687                         if (block == (&group_data[i].block_bitmap)[j]) {
 688                                 count += group_table_count[j];
 689                                 continue;
 690                         }
 691                         err = set_flexbg_block_bitmap(sb, handle,
 692                                                       flex_gd,
 693                                                       EXT4_B2C(sbi, start),
 694                                                       EXT4_B2C(sbi,
 695                                                                start + count
 696                                                                - 1));
 697                         if (err)
 698                                 goto out;
 699                         count = group_table_count[j];
 700                         start = (&group_data[i].block_bitmap)[j];
 701                         block = start;
 702                 }
 703
 704                 if (count) {
 705                         err = set_flexbg_block_bitmap(sb, handle,
 706                                                       flex_gd,
 707                                                       EXT4_B2C(sbi, start),
 708                                                       EXT4_B2C(sbi,
 709                                                                start + count
 710                                                                - 1));
 711                         if (err)
 712                                 goto out;
 713                 }
 714         }
 715
 716 out:
 717         err2 = ext4_journal_stop(handle);
 718         if (err2 && !err)
 719                 err = err2;
 720
 721         return err;
 722 }
 723
 724 /*
 725  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 726  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 727  * calling this for the first time.  In a sparse filesystem it will be the
 728  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 729  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 730  */
 731 unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three,
 732                                unsigned int *five, unsigned int *seven)
 733 {
 734         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 735         unsigned int *min = three;
 736         int mult = 3;
 737         unsigned int ret;
 738
 739         if (ext4_has_feature_sparse_super2(sb)) {
 740                 do {
 741                         if (*min > 2)
 742                                 return UINT_MAX;
 743                         ret = le32_to_cpu(es->s_backup_bgs[*min - 1]);
 744                         *min += 1;
 745                 } while (!ret);
 746                 return ret;
 747         }
 748
 749         if (!ext4_has_feature_sparse_super(sb)) {
 750                 ret = *min;
 751                 *min += 1;
 752                 return ret;
 753         }
 754
 755         if (*five < *min) {
 756                 min = five;
 757                 mult = 5;
 758         }
 759         if (*seven < *min) {
 760                 min = seven;
 761                 mult = 7;
 762         }
 763
 764         ret = *min;
 765         *min *= mult;
 766
 767         return ret;
 768 }
 769
 770 /*
 771  * Check that all of the backup GDT blocks are held in the primary GDT block.
 772  * It is assumed that they are stored in group order.  Returns the number of
 773  * groups in current filesystem that have BACKUPS, or -ve error code.
 774  */
 775 static int verify_reserved_gdb(struct super_block *sb,
 776                                ext4_group_t end,
 777                                struct buffer_head *primary)
 778 {
 779         const ext4_fsblk_t blk = primary->b_blocknr;
 780         unsigned three = 1;
 781         unsigned five = 5;
 782         unsigned seven = 7;
 783         unsigned grp;
 784         __le32 *p = (__le32 *)primary->b_data;
 785         int gdbackups = 0;
 786
 787         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 788                 if (le32_to_cpu(*p++) !=
 789                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 790                         ext4_warning(sb, "reserved GDT %llu"
 791                                      " missing grp %d (%llu)",
 792                                      blk, grp,
 793                                      grp *
 794                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 795                                      blk);
 796                         return -EINVAL;
 797                 }
 798                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 799                         return -EFBIG;
 800         }
 801
 802         return gdbackups;
 803 }
 804
 805 /*
 806  * Called when we need to bring a reserved group descriptor table block into
 807  * use from the resize inode.  The primary copy of the new GDT block currently
 808  * is an indirect block (under the double indirect block in the resize inode).
 809  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 810  * block, in group order.  Even though we know all the block numbers we need,
 811  * we check to ensure that the resize inode has actually reserved these blocks.
 812  *
 813  * Don't need to update the block bitmaps because the blocks are still in use.
 814  *
 815  * We get all of the error cases out of the way, so that we are sure to not
 816  * fail once we start modifying the data on disk, because JBD has no rollback.
 817  */
 818 static int add_new_gdb(handle_t *handle, struct inode *inode,
 819                        ext4_group_t group)
 820 {
 821         struct super_block *sb = inode->i_sb;
 822         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 823         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 824         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 825         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 826         struct buffer_head *dind = NULL;
 827         struct buffer_head *gdb_bh = NULL;
 828         int gdbackups;
 829         struct ext4_iloc iloc = { .bh = NULL };
 830         __le32 *data;
 831         int err;
 832
 833         if (test_opt(sb, DEBUG))
 834                 printk(KERN_DEBUG
 835                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 836                        gdb_num);
 837
 838         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 839         if (IS_ERR(gdb_bh))
 840                 return PTR_ERR(gdb_bh);
 841
 842         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 843         if (gdbackups < 0) {
 844                 err = gdbackups;
 845                 goto errout;
 846         }
 847
 848         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 849         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 850         if (IS_ERR(dind)) {
 851                 err = PTR_ERR(dind);
 852                 dind = NULL;
 853                 goto errout;
 854         }
 855
 856         data = (__le32 *)dind->b_data;
 857         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 858                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 859                              group, gdblock);
 860                 err = -EINVAL;
 861                 goto errout;
 862         }
 863
 864         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 865         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 866                                             EXT4_JTR_NONE);
 867         if (unlikely(err))
 868                 goto errout;
 869
 870         BUFFER_TRACE(gdb_bh, "get_write_access");
 871         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 872         if (unlikely(err))
 873                 goto errout;
 874
 875         BUFFER_TRACE(dind, "get_write_access");
 876         err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
 877         if (unlikely(err)) {
 878                 ext4_std_error(sb, err);
 879                 goto errout;
 880         }
 881
 882         /* ext4_reserve_inode_write() gets a reference on the iloc */
 883         err = ext4_reserve_inode_write(handle, inode, &iloc);
 884         if (unlikely(err))
 885                 goto errout;
 886
 887         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 888                                 GFP_KERNEL);
 889         if (!n_group_desc) {
 890                 err = -ENOMEM;
 891                 ext4_warning(sb, "not enough memory for %lu groups",
 892                              gdb_num + 1);
 893                 goto errout;
 894         }
 895
 896         /*
 897          * Finally, we have all of the possible failures behind us...
 898          *
 899          * Remove new GDT block from inode double-indirect block and clear out
 900          * the new GDT block for use (which also "frees" the backup GDT blocks
 901          * from the reserved inode).  We don't need to change the bitmaps for
 902          * these blocks, because they are marked as in-use from being in the
 903          * reserved inode, and will become GDT blocks (primary and backup).
 904          */
 905         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 906         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 907         if (unlikely(err)) {
 908                 ext4_std_error(sb, err);
 909                 goto errout;
 910         }
 911         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 912                            (9 - EXT4_SB(sb)->s_cluster_bits);
 913         ext4_mark_iloc_dirty(handle, inode, &iloc);
 914         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 915         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 916         if (unlikely(err)) {
 917                 ext4_std_error(sb, err);
 918                 iloc.bh = NULL;
 919                 goto errout;
 920         }
 921         brelse(dind);
 922
 923         rcu_read_lock();
 924         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 925         memcpy(n_group_desc, o_group_desc,
 926                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 927         rcu_read_unlock();
 928         n_group_desc[gdb_num] = gdb_bh;
 929         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 930         EXT4_SB(sb)->s_gdb_count++;
 931         ext4_kvfree_array_rcu(o_group_desc);
 932
 933         lock_buffer(EXT4_SB(sb)->s_sbh);
 934         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 935         ext4_superblock_csum_set(sb);
 936         unlock_buffer(EXT4_SB(sb)->s_sbh);
 937         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 938         if (err)
 939                 ext4_std_error(sb, err);
 940         return err;
 941 errout:
 942         kvfree(n_group_desc);
 943         brelse(iloc.bh);
 944         brelse(dind);
 945         brelse(gdb_bh);
 946
 947         ext4_debug("leaving with error %d\n", err);
 948         return err;
 949 }
 950
 951 /*
 952  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 953  */
 954 static int add_new_gdb_meta_bg(struct super_block *sb,
 955                                handle_t *handle, ext4_group_t group) {
 956         ext4_fsblk_t gdblock;
 957         struct buffer_head *gdb_bh;
 958         struct buffer_head **o_group_desc, **n_group_desc;
 959         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 960         int err;
 961
 962         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 963                    ext4_bg_has_super(sb, group);
 964         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 965         if (IS_ERR(gdb_bh))
 966                 return PTR_ERR(gdb_bh);
 967         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 968                                 GFP_KERNEL);
 969         if (!n_group_desc) {
 970                 brelse(gdb_bh);
 971                 err = -ENOMEM;
 972                 ext4_warning(sb, "not enough memory for %lu groups",
 973                              gdb_num + 1);
 974                 return err;
 975         }
 976
 977         rcu_read_lock();
 978         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 979         memcpy(n_group_desc, o_group_desc,
 980                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 981         rcu_read_unlock();
 982         n_group_desc[gdb_num] = gdb_bh;
 983
 984         BUFFER_TRACE(gdb_bh, "get_write_access");
 985         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 986         if (err) {
 987                 kvfree(n_group_desc);
 988                 brelse(gdb_bh);
 989                 return err;
 990         }
 991
 992         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 993         EXT4_SB(sb)->s_gdb_count++;
 994         ext4_kvfree_array_rcu(o_group_desc);
 995         return err;
 996 }
 997
 998 /*
 999  * Called when we are adding a new group which has a backup copy of each of
1000  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
1001  * We need to add these reserved backup GDT blocks to the resize inode, so
1002  * that they are kept for future resizing and not allocated to files.
1003  *
1004  * Each reserved backup GDT block will go into a different indirect block.
1005  * The indirect blocks are actually the primary reserved GDT blocks,
1006  * so we know in advance what their block numbers are.  We only get the
1007  * double-indirect block to verify it is pointing to the primary reserved
1008  * GDT blocks so we don't overwrite a data block by accident.  The reserved
1009  * backup GDT blocks are stored in their reserved primary GDT block.
1010  */
1011 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1012                               ext4_group_t group)
1013 {
1014         struct super_block *sb = inode->i_sb;
1015         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1016         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1017         struct buffer_head **primary;
1018         struct buffer_head *dind;
1019         struct ext4_iloc iloc;
1020         ext4_fsblk_t blk;
1021         __le32 *data, *end;
1022         int gdbackups = 0;
1023         int res, i;
1024         int err;
1025
1026         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1027         if (!primary)
1028                 return -ENOMEM;
1029
1030         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1031         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1032         if (IS_ERR(dind)) {
1033                 err = PTR_ERR(dind);
1034                 dind = NULL;
1035                 goto exit_free;
1036         }
1037
1038         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1039         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1040                                          EXT4_ADDR_PER_BLOCK(sb));
1041         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1042
1043         /* Get each reserved primary GDT block and verify it holds backups */
1044         for (res = 0; res < reserved_gdb; res++, blk++) {
1045                 if (le32_to_cpu(*data) != blk) {
1046                         ext4_warning(sb, "reserved block %llu"
1047                                      " not at offset %ld",
1048                                      blk,
1049                                      (long)(data - (__le32 *)dind->b_data));
1050                         err = -EINVAL;
1051                         goto exit_bh;
1052                 }
1053                 primary[res] = ext4_sb_bread(sb, blk, 0);
1054                 if (IS_ERR(primary[res])) {
1055                         err = PTR_ERR(primary[res]);
1056                         primary[res] = NULL;
1057                         goto exit_bh;
1058                 }
1059                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1060                 if (gdbackups < 0) {
1061                         brelse(primary[res]);
1062                         err = gdbackups;
1063                         goto exit_bh;
1064                 }
1065                 if (++data >= end)
1066                         data = (__le32 *)dind->b_data;
1067         }
1068
1069         for (i = 0; i < reserved_gdb; i++) {
1070                 BUFFER_TRACE(primary[i], "get_write_access");
1071                 if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1072                                                          EXT4_JTR_NONE)))
1073                         goto exit_bh;
1074         }
1075
1076         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1077                 goto exit_bh;
1078
1079         /*
1080          * Finally we can add each of the reserved backup GDT blocks from
1081          * the new group to its reserved primary GDT block.
1082          */
1083         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1084         for (i = 0; i < reserved_gdb; i++) {
1085                 int err2;
1086                 data = (__le32 *)primary[i]->b_data;
1087                 /* printk("reserving backup %lu[%u] = %lu\n",
1088                        primary[i]->b_blocknr, gdbackups,
1089                        blk + primary[i]->b_blocknr); */
1090                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1091                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1092                 if (!err)
1093                         err = err2;
1094         }
1095
1096         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1097         ext4_mark_iloc_dirty(handle, inode, &iloc);
1098
1099 exit_bh:
1100         while (--res >= 0)
1101                 brelse(primary[res]);
1102         brelse(dind);
1103
1104 exit_free:
1105         kfree(primary);
1106
1107         return err;
1108 }
1109
1110 /*
1111  * Update the backup copies of the ext4 metadata.  These don't need to be part
1112  * of the main resize transaction, because e2fsck will re-write them if there
1113  * is a problem (basically only OOM will cause a problem).  However, we
1114  * _should_ update the backups if possible, in case the primary gets trashed
1115  * for some reason and we need to run e2fsck from a backup superblock.  The
1116  * important part is that the new block and inode counts are in the backup
1117  * superblocks, and the location of the new group metadata in the GDT backups.
1118  *
1119  * We do not need take the s_resize_lock for this, because these
1120  * blocks are not otherwise touched by the filesystem code when it is
1121  * mounted.  We don't need to worry about last changing from
1122  * sbi->s_groups_count, because the worst that can happen is that we
1123  * do not copy the full number of backups at this time.  The resize
1124  * which changed s_groups_count will backup again.
1125  */
1126 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1127                            int size, int meta_bg)
1128 {
1129         struct ext4_sb_info *sbi = EXT4_SB(sb);
1130         ext4_group_t last;
1131         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1132         unsigned three = 1;
1133         unsigned five = 5;
1134         unsigned seven = 7;
1135         ext4_group_t group = 0;
1136         int rest = sb->s_blocksize - size;
1137         handle_t *handle;
1138         int err = 0, err2;
1139
1140         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1141         if (IS_ERR(handle)) {
1142                 group = 1;
1143                 err = PTR_ERR(handle);
1144                 goto exit_err;
1145         }
1146
1147         if (meta_bg == 0) {
1148                 group = ext4_list_backups(sb, &three, &five, &seven);
1149                 last = sbi->s_groups_count;
1150         } else {
1151                 group = ext4_get_group_number(sb, blk_off) + 1;
1152                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1153         }
1154
1155         while (group < sbi->s_groups_count) {
1156                 struct buffer_head *bh;
1157                 ext4_fsblk_t backup_block;
1158
1159                 /* Out of journal space, and can't get more - abort - so sad */
1160                 err = ext4_resize_ensure_credits_batch(handle, 1);
1161                 if (err < 0)
1162                         break;
1163
1164                 if (meta_bg == 0)
1165                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1166                 else
1167                         backup_block = (ext4_group_first_block_no(sb, group) +
1168                                         ext4_bg_has_super(sb, group));
1169
1170                 bh = sb_getblk(sb, backup_block);
1171                 if (unlikely(!bh)) {
1172                         err = -ENOMEM;
1173                         break;
1174                 }
1175                 ext4_debug("update metadata backup %llu(+%llu)\n",
1176                            backup_block, backup_block -
1177                            ext4_group_first_block_no(sb, group));
1178                 BUFFER_TRACE(bh, "get_write_access");
1179                 if ((err = ext4_journal_get_write_access(handle, sb, bh,
1180                                                          EXT4_JTR_NONE)))
1181                         break;
1182                 lock_buffer(bh);
1183                 memcpy(bh->b_data, data, size);
1184                 if (rest)
1185                         memset(bh->b_data + size, 0, rest);
1186                 set_buffer_uptodate(bh);
1187                 unlock_buffer(bh);
1188                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1189                 if (unlikely(err))
1190                         ext4_std_error(sb, err);
1191                 brelse(bh);
1192
1193                 if (meta_bg == 0)
1194                         group = ext4_list_backups(sb, &three, &five, &seven);
1195                 else if (group == last)
1196                         break;
1197                 else
1198                         group = last;
1199         }
1200         if ((err2 = ext4_journal_stop(handle)) && !err)
1201                 err = err2;
1202
1203         /*
1204          * Ugh! Need to have e2fsck write the backup copies.  It is too
1205          * late to revert the resize, we shouldn't fail just because of
1206          * the backup copies (they are only needed in case of corruption).
1207          *
1208          * However, if we got here we have a journal problem too, so we
1209          * can't really start a transaction to mark the superblock.
1210          * Chicken out and just set the flag on the hope it will be written
1211          * to disk, and if not - we will simply wait until next fsck.
1212          */
1213 exit_err:
1214         if (err) {
1215                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1216                              "forcing fsck on next reboot", group, err);
1217                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1218                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1219                 mark_buffer_dirty(sbi->s_sbh);
1220         }
1221 }
1222
1223 /*
1224  * ext4_add_new_descs() adds @count group descriptor of groups
1225  * starting at @group
1226  *
1227  * @handle: journal handle
1228  * @sb: super block
1229  * @group: the group no. of the first group desc to be added
1230  * @resize_inode: the resize inode
1231  * @count: number of group descriptors to be added
1232  */
1233 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1234                               ext4_group_t group, struct inode *resize_inode,
1235                               ext4_group_t count)
1236 {
1237         struct ext4_sb_info *sbi = EXT4_SB(sb);
1238         struct ext4_super_block *es = sbi->s_es;
1239         struct buffer_head *gdb_bh;
1240         int i, gdb_off, gdb_num, err = 0;
1241         int meta_bg;
1242
1243         meta_bg = ext4_has_feature_meta_bg(sb);
1244         for (i = 0; i < count; i++, group++) {
1245                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1246                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1247
1248                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1249                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1250
1251                 /*
1252                  * We will only either add reserved group blocks to a backup group
1253                  * or remove reserved blocks for the first group in a new group block.
1254                  * Doing both would be mean more complex code, and sane people don't
1255                  * use non-sparse filesystems anymore.  This is already checked above.
1256                  */
1257                 if (gdb_off) {
1258                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1259                                                      gdb_num);
1260                         BUFFER_TRACE(gdb_bh, "get_write_access");
1261                         err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1262                                                             EXT4_JTR_NONE);
1263
1264                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1265                                 err = reserve_backup_gdb(handle, resize_inode, group);
1266                 } else if (meta_bg != 0) {
1267                         err = add_new_gdb_meta_bg(sb, handle, group);
1268                 } else {
1269                         err = add_new_gdb(handle, resize_inode, group);
1270                 }
1271                 if (err)
1272                         break;
1273         }
1274         return err;
1275 }
1276
1277 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1278 {
1279         struct buffer_head *bh = sb_getblk(sb, block);
1280         if (unlikely(!bh))
1281                 return NULL;
1282         if (!bh_uptodate_or_lock(bh)) {
1283                 if (ext4_read_bh(bh, 0, NULL) < 0) {
1284                         brelse(bh);
1285                         return NULL;
1286                 }
1287         }
1288
1289         return bh;
1290 }
1291
1292 static int ext4_set_bitmap_checksums(struct super_block *sb,
1293                                      ext4_group_t group,
1294                                      struct ext4_group_desc *gdp,
1295                                      struct ext4_new_group_data *group_data)
1296 {
1297         struct buffer_head *bh;
1298
1299         if (!ext4_has_metadata_csum(sb))
1300                 return 0;
1301
1302         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1303         if (!bh)
1304                 return -EIO;
1305         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1306                                    EXT4_INODES_PER_GROUP(sb) / 8);
1307         brelse(bh);
1308
1309         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1310         if (!bh)
1311                 return -EIO;
1312         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1313         brelse(bh);
1314
1315         return 0;
1316 }
1317
1318 /*
1319  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1320  */
1321 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1322                                 struct ext4_new_flex_group_data *flex_gd)
1323 {
1324         struct ext4_new_group_data      *group_data = flex_gd->groups;
1325         struct ext4_group_desc          *gdp;
1326         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1327         struct buffer_head              *gdb_bh;
1328         ext4_group_t                    group;
1329         __u16                           *bg_flags = flex_gd->bg_flags;
1330         int                             i, gdb_off, gdb_num, err = 0;
1331
1332
1333         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1334                 group = group_data->group;
1335
1336                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1337                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1338
1339                 /*
1340                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1341                  */
1342                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1343                 /* Update group descriptor block for new group */
1344                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1345                                                  gdb_off * EXT4_DESC_SIZE(sb));
1346
1347                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1348                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1349                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1350                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1351                 if (err) {
1352                         ext4_std_error(sb, err);
1353                         break;
1354                 }
1355
1356                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1357                 ext4_free_group_clusters_set(sb, gdp,
1358                                              group_data->free_clusters_count);
1359                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1360                 if (ext4_has_group_desc_csum(sb))
1361                         ext4_itable_unused_set(sb, gdp,
1362                                                EXT4_INODES_PER_GROUP(sb));
1363                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1364                 ext4_group_desc_csum_set(sb, group, gdp);
1365
1366                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1367                 if (unlikely(err)) {
1368                         ext4_std_error(sb, err);
1369                         break;
1370                 }
1371
1372                 /*
1373                  * We can allocate memory for mb_alloc based on the new group
1374                  * descriptor
1375                  */
1376                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1377                 if (err)
1378                         break;
1379         }
1380         return err;
1381 }
1382
1383 /*
1384  * ext4_update_super() updates the super block so that the newly added
1385  * groups can be seen by the filesystem.
1386  *
1387  * @sb: super block
1388  * @flex_gd: new added groups
1389  */
1390 static void ext4_update_super(struct super_block *sb,
1391                              struct ext4_new_flex_group_data *flex_gd)
1392 {
1393         ext4_fsblk_t blocks_count = 0;
1394         ext4_fsblk_t free_blocks = 0;
1395         ext4_fsblk_t reserved_blocks = 0;
1396         struct ext4_new_group_data *group_data = flex_gd->groups;
1397         struct ext4_sb_info *sbi = EXT4_SB(sb);
1398         struct ext4_super_block *es = sbi->s_es;
1399         int i;
1400
1401         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1402         /*
1403          * Make the new blocks and inodes valid next.  We do this before
1404          * increasing the group count so that once the group is enabled,
1405          * all of its blocks and inodes are already valid.
1406          *
1407          * We always allocate group-by-group, then block-by-block or
1408          * inode-by-inode within a group, so enabling these
1409          * blocks/inodes before the group is live won't actually let us
1410          * allocate the new space yet.
1411          */
1412         for (i = 0; i < flex_gd->count; i++) {
1413                 blocks_count += group_data[i].blocks_count;
1414                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1415         }
1416
1417         reserved_blocks = ext4_r_blocks_count(es) * 100;
1418         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1419         reserved_blocks *= blocks_count;
1420         do_div(reserved_blocks, 100);
1421
1422         lock_buffer(sbi->s_sbh);
1423         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1424         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1425         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1426                      flex_gd->count);
1427         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1428                      flex_gd->count);
1429
1430         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1431         /*
1432          * We need to protect s_groups_count against other CPUs seeing
1433          * inconsistent state in the superblock.
1434          *
1435          * The precise rules we use are:
1436          *
1437          * * Writers must perform a smp_wmb() after updating all
1438          *   dependent data and before modifying the groups count
1439          *
1440          * * Readers must perform an smp_rmb() after reading the groups
1441          *   count and before reading any dependent data.
1442          *
1443          * NB. These rules can be relaxed when checking the group count
1444          * while freeing data, as we can only allocate from a block
1445          * group after serialising against the group count, and we can
1446          * only then free after serialising in turn against that
1447          * allocation.
1448          */
1449         smp_wmb();
1450
1451         /* Update the global fs size fields */
1452         sbi->s_groups_count += flex_gd->count;
1453         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1454                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1455
1456         /* Update the reserved block counts only once the new group is
1457          * active. */
1458         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1459                                 reserved_blocks);
1460         ext4_superblock_csum_set(sb);
1461         unlock_buffer(sbi->s_sbh);
1462
1463         /* Update the free space counts */
1464         percpu_counter_add(&sbi->s_freeclusters_counter,
1465                            EXT4_NUM_B2C(sbi, free_blocks));
1466         percpu_counter_add(&sbi->s_freeinodes_counter,
1467                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1468
1469         ext4_debug("free blocks count %llu",
1470                    percpu_counter_read(&sbi->s_freeclusters_counter));
1471         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1472                 ext4_group_t flex_group;
1473                 struct flex_groups *fg;
1474
1475                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1476                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1477                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1478                              &fg->free_clusters);
1479                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1480                            &fg->free_inodes);
1481         }
1482
1483         /*
1484          * Update the fs overhead information
1485          */
1486         ext4_calculate_overhead(sb);
1487
1488         if (test_opt(sb, DEBUG))
1489                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1490                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1491                        blocks_count, free_blocks, reserved_blocks);
1492 }
1493
1494 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1495  * _before_ we start modifying the filesystem, because we cannot abort the
1496  * transaction and not have it write the data to disk.
1497  */
1498 static int ext4_flex_group_add(struct super_block *sb,
1499                                struct inode *resize_inode,
1500                                struct ext4_new_flex_group_data *flex_gd)
1501 {
1502         struct ext4_sb_info *sbi = EXT4_SB(sb);
1503         struct ext4_super_block *es = sbi->s_es;
1504         ext4_fsblk_t o_blocks_count;
1505         ext4_grpblk_t last;
1506         ext4_group_t group;
1507         handle_t *handle;
1508         unsigned reserved_gdb;
1509         int err = 0, err2 = 0, credit;
1510
1511         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1512
1513         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1514         o_blocks_count = ext4_blocks_count(es);
1515         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1516         BUG_ON(last);
1517
1518         err = setup_new_flex_group_blocks(sb, flex_gd);
1519         if (err)
1520                 goto exit;
1521         /*
1522          * We will always be modifying at least the superblock and  GDT
1523          * blocks.  If we are adding a group past the last current GDT block,
1524          * we will also modify the inode and the dindirect block.  If we
1525          * are adding a group with superblock/GDT backups  we will also
1526          * modify each of the reserved GDT dindirect blocks.
1527          */
1528         credit = 3;     /* sb, resize inode, resize inode dindirect */
1529         /* GDT blocks */
1530         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1531         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1532         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1533         if (IS_ERR(handle)) {
1534                 err = PTR_ERR(handle);
1535                 goto exit;
1536         }
1537
1538         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1539         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1540                                             EXT4_JTR_NONE);
1541         if (err)
1542                 goto exit_journal;
1543
1544         group = flex_gd->groups[0].group;
1545         BUG_ON(group != sbi->s_groups_count);
1546         err = ext4_add_new_descs(handle, sb, group,
1547                                 resize_inode, flex_gd->count);
1548         if (err)
1549                 goto exit_journal;
1550
1551         err = ext4_setup_new_descs(handle, sb, flex_gd);
1552         if (err)
1553                 goto exit_journal;
1554
1555         ext4_update_super(sb, flex_gd);
1556
1557         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1558
1559 exit_journal:
1560         err2 = ext4_journal_stop(handle);
1561         if (!err)
1562                 err = err2;
1563
1564         if (!err) {
1565                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1566                 int gdb_num_end = ((group + flex_gd->count - 1) /
1567                                    EXT4_DESC_PER_BLOCK(sb));
1568                 int meta_bg = ext4_has_feature_meta_bg(sb);
1569                 sector_t old_gdb = 0;
1570
1571                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1572                                sizeof(struct ext4_super_block), 0);
1573                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1574                         struct buffer_head *gdb_bh;
1575
1576                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1577                                                      gdb_num);
1578                         if (old_gdb == gdb_bh->b_blocknr)
1579                                 continue;
1580                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1581                                        gdb_bh->b_size, meta_bg);
1582                         old_gdb = gdb_bh->b_blocknr;
1583                 }
1584         }
1585 exit:
1586         return err;
1587 }
1588
1589 static int ext4_setup_next_flex_gd(struct super_block *sb,
1590                                     struct ext4_new_flex_group_data *flex_gd,
1591                                     ext4_fsblk_t n_blocks_count,
1592                                     unsigned long flexbg_size)
1593 {
1594         struct ext4_sb_info *sbi = EXT4_SB(sb);
1595         struct ext4_super_block *es = sbi->s_es;
1596         struct ext4_new_group_data *group_data = flex_gd->groups;
1597         ext4_fsblk_t o_blocks_count;
1598         ext4_group_t n_group;
1599         ext4_group_t group;
1600         ext4_group_t last_group;
1601         ext4_grpblk_t last;
1602         ext4_grpblk_t clusters_per_group;
1603         unsigned long i;
1604
1605         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1606
1607         o_blocks_count = ext4_blocks_count(es);
1608
1609         if (o_blocks_count == n_blocks_count)
1610                 return 0;
1611
1612         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1613         BUG_ON(last);
1614         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1615
1616         last_group = group | (flexbg_size - 1);
1617         if (last_group > n_group)
1618                 last_group = n_group;
1619
1620         flex_gd->count = last_group - group + 1;
1621
1622         for (i = 0; i < flex_gd->count; i++) {
1623                 int overhead;
1624
1625                 group_data[i].group = group + i;
1626                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1627                 overhead = ext4_group_overhead_blocks(sb, group + i);
1628                 group_data[i].mdata_blocks = overhead;
1629                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1630                 if (ext4_has_group_desc_csum(sb)) {
1631                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1632                                                EXT4_BG_INODE_UNINIT;
1633                         if (!test_opt(sb, INIT_INODE_TABLE))
1634                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1635                 } else
1636                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1637         }
1638
1639         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1640                 /* We need to initialize block bitmap of last group. */
1641                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1642
1643         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1644                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1645                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1646                                                        last - 1;
1647         }
1648
1649         return 1;
1650 }
1651
1652 /* Add group descriptor data to an existing or new group descriptor block.
1653  * Ensure we handle all possible error conditions _before_ we start modifying
1654  * the filesystem, because we cannot abort the transaction and not have it
1655  * write the data to disk.
1656  *
1657  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1658  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1659  *
1660  * We only need to hold the superblock lock while we are actually adding
1661  * in the new group's counts to the superblock.  Prior to that we have
1662  * not really "added" the group at all.  We re-check that we are still
1663  * adding in the last group in case things have changed since verifying.
1664  */
1665 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1666 {
1667         struct ext4_new_flex_group_data flex_gd;
1668         struct ext4_sb_info *sbi = EXT4_SB(sb);
1669         struct ext4_super_block *es = sbi->s_es;
1670         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1671                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1672         struct inode *inode = NULL;
1673         int gdb_off;
1674         int err;
1675         __u16 bg_flags = 0;
1676
1677         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1678
1679         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1680                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1681                 return -EPERM;
1682         }
1683
1684         if (ext4_blocks_count(es) + input->blocks_count <
1685             ext4_blocks_count(es)) {
1686                 ext4_warning(sb, "blocks_count overflow");
1687                 return -EINVAL;
1688         }
1689
1690         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1691             le32_to_cpu(es->s_inodes_count)) {
1692                 ext4_warning(sb, "inodes_count overflow");
1693                 return -EINVAL;
1694         }
1695
1696         if (reserved_gdb || gdb_off == 0) {
1697                 if (!ext4_has_feature_resize_inode(sb) ||
1698                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1699                         ext4_warning(sb,
1700                                      "No reserved GDT blocks, can't resize");
1701                         return -EPERM;
1702                 }
1703                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1704                 if (IS_ERR(inode)) {
1705                         ext4_warning(sb, "Error opening resize inode");
1706                         return PTR_ERR(inode);
1707                 }
1708         }
1709
1710
1711         err = verify_group_input(sb, input);
1712         if (err)
1713                 goto out;
1714
1715         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1716         if (err)
1717                 goto out;
1718
1719         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1720         if (err)
1721                 goto out;
1722
1723         flex_gd.count = 1;
1724         flex_gd.groups = input;
1725         flex_gd.bg_flags = &bg_flags;
1726         err = ext4_flex_group_add(sb, inode, &flex_gd);
1727 out:
1728         iput(inode);
1729         return err;
1730 } /* ext4_group_add */
1731
1732 /*
1733  * extend a group without checking assuming that checking has been done.
1734  */
1735 static int ext4_group_extend_no_check(struct super_block *sb,
1736                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1737 {
1738         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1739         handle_t *handle;
1740         int err = 0, err2;
1741
1742         /* We will update the superblock, one block bitmap, and
1743          * one group descriptor via ext4_group_add_blocks().
1744          */
1745         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1746         if (IS_ERR(handle)) {
1747                 err = PTR_ERR(handle);
1748                 ext4_warning(sb, "error %d on journal start", err);
1749                 return err;
1750         }
1751
1752         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1753         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1754                                             EXT4_JTR_NONE);
1755         if (err) {
1756                 ext4_warning(sb, "error %d on journal write access", err);
1757                 goto errout;
1758         }
1759
1760         lock_buffer(EXT4_SB(sb)->s_sbh);
1761         ext4_blocks_count_set(es, o_blocks_count + add);
1762         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1763         ext4_superblock_csum_set(sb);
1764         unlock_buffer(EXT4_SB(sb)->s_sbh);
1765         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1766                    o_blocks_count + add);
1767         /* We add the blocks to the bitmap and set the group need init bit */
1768         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1769         if (err)
1770                 goto errout;
1771         ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1772         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1773                    o_blocks_count + add);
1774 errout:
1775         err2 = ext4_journal_stop(handle);
1776         if (err2 && !err)
1777                 err = err2;
1778
1779         if (!err) {
1780                 if (test_opt(sb, DEBUG))
1781                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1782                                "blocks\n", ext4_blocks_count(es));
1783                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1784                                (char *)es, sizeof(struct ext4_super_block), 0);
1785         }
1786         return err;
1787 }
1788
1789 /*
1790  * Extend the filesystem to the new number of blocks specified.  This entry
1791  * point is only used to extend the current filesystem to the end of the last
1792  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1793  * for emergencies (because it has no dependencies on reserved blocks).
1794  *
1795  * If we _really_ wanted, we could use default values to call ext4_group_add()
1796  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1797  * GDT blocks are reserved to grow to the desired size.
1798  */
1799 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1800                       ext4_fsblk_t n_blocks_count)
1801 {
1802         ext4_fsblk_t o_blocks_count;
1803         ext4_grpblk_t last;
1804         ext4_grpblk_t add;
1805         struct buffer_head *bh;
1806         int err;
1807         ext4_group_t group;
1808
1809         o_blocks_count = ext4_blocks_count(es);
1810
1811         if (test_opt(sb, DEBUG))
1812                 ext4_msg(sb, KERN_DEBUG,
1813                          "extending last group from %llu to %llu blocks",
1814                          o_blocks_count, n_blocks_count);
1815
1816         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1817                 return 0;
1818
1819         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1820                 ext4_msg(sb, KERN_ERR,
1821                          "filesystem too large to resize to %llu blocks safely",
1822                          n_blocks_count);
1823                 return -EINVAL;
1824         }
1825
1826         if (n_blocks_count < o_blocks_count) {
1827                 ext4_warning(sb, "can't shrink FS - resize aborted");
1828                 return -EINVAL;
1829         }
1830
1831         /* Handle the remaining blocks in the last group only. */
1832         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1833
1834         if (last == 0) {
1835                 ext4_warning(sb, "need to use ext2online to resize further");
1836                 return -EPERM;
1837         }
1838
1839         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1840
1841         if (o_blocks_count + add < o_blocks_count) {
1842                 ext4_warning(sb, "blocks_count overflow");
1843                 return -EINVAL;
1844         }
1845
1846         if (o_blocks_count + add > n_blocks_count)
1847                 add = n_blocks_count - o_blocks_count;
1848
1849         if (o_blocks_count + add < n_blocks_count)
1850                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1851                              o_blocks_count + add, add);
1852
1853         /* See if the device is actually as big as what was requested */
1854         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1855         if (IS_ERR(bh)) {
1856                 ext4_warning(sb, "can't read last block, resize aborted");
1857                 return -ENOSPC;
1858         }
1859         brelse(bh);
1860
1861         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1862         return err;
1863 } /* ext4_group_extend */
1864
1865
1866 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1867 {
1868         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1869 }
1870
1871 /*
1872  * Release the resize inode and drop the resize_inode feature if there
1873  * are no more reserved gdt blocks, and then convert the file system
1874  * to enable meta_bg
1875  */
1876 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1877 {
1878         handle_t *handle;
1879         struct ext4_sb_info *sbi = EXT4_SB(sb);
1880         struct ext4_super_block *es = sbi->s_es;
1881         struct ext4_inode_info *ei = EXT4_I(inode);
1882         ext4_fsblk_t nr;
1883         int i, ret, err = 0;
1884         int credits = 1;
1885
1886         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1887         if (inode) {
1888                 if (es->s_reserved_gdt_blocks) {
1889                         ext4_error(sb, "Unexpected non-zero "
1890                                    "s_reserved_gdt_blocks");
1891                         return -EPERM;
1892                 }
1893
1894                 /* Do a quick sanity check of the resize inode */
1895                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1896                                              (9 - sbi->s_cluster_bits)))
1897                         goto invalid_resize_inode;
1898                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1899                         if (i == EXT4_DIND_BLOCK) {
1900                                 if (ei->i_data[i])
1901                                         continue;
1902                                 else
1903                                         goto invalid_resize_inode;
1904                         }
1905                         if (ei->i_data[i])
1906                                 goto invalid_resize_inode;
1907                 }
1908                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1909         }
1910
1911         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1912         if (IS_ERR(handle))
1913                 return PTR_ERR(handle);
1914
1915         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1916         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1917                                             EXT4_JTR_NONE);
1918         if (err)
1919                 goto errout;
1920
1921         lock_buffer(sbi->s_sbh);
1922         ext4_clear_feature_resize_inode(sb);
1923         ext4_set_feature_meta_bg(sb);
1924         sbi->s_es->s_first_meta_bg =
1925                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1926         ext4_superblock_csum_set(sb);
1927         unlock_buffer(sbi->s_sbh);
1928
1929         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1930         if (err) {
1931                 ext4_std_error(sb, err);
1932                 goto errout;
1933         }
1934
1935         if (inode) {
1936                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1937                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1938                                  EXT4_FREE_BLOCKS_METADATA |
1939                                  EXT4_FREE_BLOCKS_FORGET);
1940                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1941                 inode->i_blocks = 0;
1942
1943                 err = ext4_mark_inode_dirty(handle, inode);
1944                 if (err)
1945                         ext4_std_error(sb, err);
1946         }
1947
1948 errout:
1949         ret = ext4_journal_stop(handle);
1950         if (!err)
1951                 err = ret;
1952         return ret;
1953
1954 invalid_resize_inode:
1955         ext4_error(sb, "corrupted/inconsistent resize inode");
1956         return -EINVAL;
1957 }
1958
1959 /*
1960  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1961  *
1962  * @sb: super block of the fs to be resized
1963  * @n_blocks_count: the number of blocks resides in the resized fs
1964  */
1965 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1966 {
1967         struct ext4_new_flex_group_data *flex_gd = NULL;
1968         struct ext4_sb_info *sbi = EXT4_SB(sb);
1969         struct ext4_super_block *es = sbi->s_es;
1970         struct buffer_head *bh;
1971         struct inode *resize_inode = NULL;
1972         ext4_grpblk_t add, offset;
1973         unsigned long n_desc_blocks;
1974         unsigned long o_desc_blocks;
1975         ext4_group_t o_group;
1976         ext4_group_t n_group;
1977         ext4_fsblk_t o_blocks_count;
1978         ext4_fsblk_t n_blocks_count_retry = 0;
1979         unsigned long last_update_time = 0;
1980         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1981         int meta_bg;
1982
1983         /* See if the device is actually as big as what was requested */
1984         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
1985         if (IS_ERR(bh)) {
1986                 ext4_warning(sb, "can't read last block, resize aborted");
1987                 return -ENOSPC;
1988         }
1989         brelse(bh);
1990
1991 retry:
1992         o_blocks_count = ext4_blocks_count(es);
1993
1994         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1995                  "to %llu blocks", o_blocks_count, n_blocks_count);
1996
1997         if (n_blocks_count < o_blocks_count) {
1998                 /* On-line shrinking not supported */
1999                 ext4_warning(sb, "can't shrink FS - resize aborted");
2000                 return -EINVAL;
2001         }
2002
2003         if (n_blocks_count == o_blocks_count)
2004                 /* Nothing need to do */
2005                 return 0;
2006
2007         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
2008         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2009                 ext4_warning(sb, "resize would cause inodes_count overflow");
2010                 return -EINVAL;
2011         }
2012         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2013
2014         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2015         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2016
2017         meta_bg = ext4_has_feature_meta_bg(sb);
2018
2019         if (ext4_has_feature_resize_inode(sb)) {
2020                 if (meta_bg) {
2021                         ext4_error(sb, "resize_inode and meta_bg enabled "
2022                                    "simultaneously");
2023                         return -EINVAL;
2024                 }
2025                 if (n_desc_blocks > o_desc_blocks +
2026                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
2027                         n_blocks_count_retry = n_blocks_count;
2028                         n_desc_blocks = o_desc_blocks +
2029                                 le16_to_cpu(es->s_reserved_gdt_blocks);
2030                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2031                         n_blocks_count = (ext4_fsblk_t)n_group *
2032                                 EXT4_BLOCKS_PER_GROUP(sb) +
2033                                 le32_to_cpu(es->s_first_data_block);
2034                         n_group--; /* set to last group number */
2035                 }
2036
2037                 if (!resize_inode)
2038                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2039                                                  EXT4_IGET_SPECIAL);
2040                 if (IS_ERR(resize_inode)) {
2041                         ext4_warning(sb, "Error opening resize inode");
2042                         return PTR_ERR(resize_inode);
2043                 }
2044         }
2045
2046         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2047                 err = ext4_convert_meta_bg(sb, resize_inode);
2048                 if (err)
2049                         goto out;
2050                 if (resize_inode) {
2051                         iput(resize_inode);
2052                         resize_inode = NULL;
2053                 }
2054                 if (n_blocks_count_retry) {
2055                         n_blocks_count = n_blocks_count_retry;
2056                         n_blocks_count_retry = 0;
2057                         goto retry;
2058                 }
2059         }
2060
2061         /*
2062          * Make sure the last group has enough space so that it's
2063          * guaranteed to have enough space for all metadata blocks
2064          * that it might need to hold.  (We might not need to store
2065          * the inode table blocks in the last block group, but there
2066          * will be cases where this might be needed.)
2067          */
2068         if ((ext4_group_first_block_no(sb, n_group) +
2069              ext4_group_overhead_blocks(sb, n_group) + 2 +
2070              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2071                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2072                 n_group--;
2073                 n_blocks_count_retry = 0;
2074                 if (resize_inode) {
2075                         iput(resize_inode);
2076                         resize_inode = NULL;
2077                 }
2078                 goto retry;
2079         }
2080
2081         /* extend the last group */
2082         if (n_group == o_group)
2083                 add = n_blocks_count - o_blocks_count;
2084         else
2085                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2086         if (add > 0) {
2087                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2088                 if (err)
2089                         goto out;
2090         }
2091
2092         if (ext4_blocks_count(es) == n_blocks_count)
2093                 goto out;
2094
2095         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2096         if (err)
2097                 goto out;
2098
2099         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2100         if (err)
2101                 goto out;
2102
2103         flex_gd = alloc_flex_gd(flexbg_size);
2104         if (flex_gd == NULL) {
2105                 err = -ENOMEM;
2106                 goto out;
2107         }
2108
2109         /* Add flex groups. Note that a regular group is a
2110          * flex group with 1 group.
2111          */
2112         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2113                                               flexbg_size)) {
2114                 if (time_is_before_jiffies(last_update_time + HZ * 10)) {
2115                         if (last_update_time)
2116                                 ext4_msg(sb, KERN_INFO,
2117                                          "resized to %llu blocks",
2118                                          ext4_blocks_count(es));
2119                         last_update_time = jiffies;
2120                 }
2121                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2122                         break;
2123                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2124                 if (unlikely(err))
2125                         break;
2126         }
2127
2128         if (!err && n_blocks_count_retry) {
2129                 n_blocks_count = n_blocks_count_retry;
2130                 n_blocks_count_retry = 0;
2131                 free_flex_gd(flex_gd);
2132                 flex_gd = NULL;
2133                 if (resize_inode) {
2134                         iput(resize_inode);
2135                         resize_inode = NULL;
2136                 }
2137                 goto retry;
2138         }
2139
2140 out:
2141         if (flex_gd)
2142                 free_flex_gd(flex_gd);
2143         if (resize_inode != NULL)
2144                 iput(resize_inode);
2145         if (err)
2146                 ext4_warning(sb, "error (%d) occurred during "
2147                              "file system resize", err);
2148         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2149                  ext4_blocks_count(es));
2150         return err;
2151 }