fs/ext4/resize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/resize.c
   4  *
   5  * Support for resizing an ext4 filesystem while it is mounted.
   6  *
   7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17
  18 #include "ext4_jbd2.h"
  19
  20 struct ext4_rcu_ptr {
  21         struct rcu_head rcu;
  22         void *ptr;
  23 };
  24
  25 static void ext4_rcu_ptr_callback(struct rcu_head *head)
  26 {
  27         struct ext4_rcu_ptr *ptr;
  28
  29         ptr = container_of(head, struct ext4_rcu_ptr, rcu);
  30         kvfree(ptr->ptr);
  31         kfree(ptr);
  32 }
  33
  34 void ext4_kvfree_array_rcu(void *to_free)
  35 {
  36         struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
  37
  38         if (ptr) {
  39                 ptr->ptr = to_free;
  40                 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
  41                 return;
  42         }
  43         synchronize_rcu();
  44         kvfree(to_free);
  45 }
  46
  47 int ext4_resize_begin(struct super_block *sb)
  48 {
  49         struct ext4_sb_info *sbi = EXT4_SB(sb);
  50         int ret = 0;
  51
  52         if (!capable(CAP_SYS_RESOURCE))
  53                 return -EPERM;
  54
  55         /*
  56          * If the reserved GDT blocks is non-zero, the resize_inode feature
  57          * should always be set.
  58          */
  59         if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
  60             !ext4_has_feature_resize_inode(sb)) {
  61                 ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
  62                 return -EFSCORRUPTED;
  63         }
  64
  65         /*
  66          * If we are not using the primary superblock/GDT copy don't resize,
  67          * because the user tools have no way of handling this.  Probably a
  68          * bad time to do it anyways.
  69          */
  70         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  71             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  72                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  73                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  74                 return -EPERM;
  75         }
  76
  77         /*
  78          * We are not allowed to do online-resizing on a filesystem mounted
  79          * with error, because it can destroy the filesystem easily.
  80          */
  81         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  82                 ext4_warning(sb, "There are errors in the filesystem, "
  83                              "so online resizing is not allowed");
  84                 return -EPERM;
  85         }
  86
  87         if (ext4_has_feature_sparse_super2(sb)) {
  88                 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
  89                 return -EOPNOTSUPP;
  90         }
  91
  92         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  93                                   &EXT4_SB(sb)->s_ext4_flags))
  94                 ret = -EBUSY;
  95
  96         return ret;
  97 }
  98
  99 void ext4_resize_end(struct super_block *sb)
 100 {
 101         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
 102         smp_mb__after_atomic();
 103 }
 104
 105 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
 106                                              ext4_group_t group) {
 107         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
 108                EXT4_DESC_PER_BLOCK_BITS(sb);
 109 }
 110
 111 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
 112                                              ext4_group_t group) {
 113         group = ext4_meta_bg_first_group(sb, group);
 114         return ext4_group_first_block_no(sb, group);
 115 }
 116
 117 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 118                                                 ext4_group_t group) {
 119         ext4_grpblk_t overhead;
 120         overhead = ext4_bg_num_gdb(sb, group);
 121         if (ext4_bg_has_super(sb, group))
 122                 overhead += 1 +
 123                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 124         return overhead;
 125 }
 126
 127 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
 128 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
 129
 130 static int verify_group_input(struct super_block *sb,
 131                               struct ext4_new_group_data *input)
 132 {
 133         struct ext4_sb_info *sbi = EXT4_SB(sb);
 134         struct ext4_super_block *es = sbi->s_es;
 135         ext4_fsblk_t start = ext4_blocks_count(es);
 136         ext4_fsblk_t end = start + input->blocks_count;
 137         ext4_group_t group = input->group;
 138         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 139         unsigned overhead;
 140         ext4_fsblk_t metaend;
 141         struct buffer_head *bh = NULL;
 142         ext4_grpblk_t free_blocks_count, offset;
 143         int err = -EINVAL;
 144
 145         if (group != sbi->s_groups_count) {
 146                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 147                              input->group, sbi->s_groups_count);
 148                 return -EINVAL;
 149         }
 150
 151         overhead = ext4_group_overhead_blocks(sb, group);
 152         metaend = start + overhead;
 153         input->free_clusters_count = free_blocks_count =
 154                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 155
 156         if (test_opt(sb, DEBUG))
 157                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 158                        "(%d free, %u reserved)\n",
 159                        ext4_bg_has_super(sb, input->group) ? "normal" :
 160                        "no-super", input->group, input->blocks_count,
 161                        free_blocks_count, input->reserved_blocks);
 162
 163         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 164         if (offset != 0)
 165                         ext4_warning(sb, "Last group not full");
 166         else if (input->reserved_blocks > input->blocks_count / 5)
 167                 ext4_warning(sb, "Reserved blocks too high (%u)",
 168                              input->reserved_blocks);
 169         else if (free_blocks_count < 0)
 170                 ext4_warning(sb, "Bad blocks count %u",
 171                              input->blocks_count);
 172         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 173                 err = PTR_ERR(bh);
 174                 bh = NULL;
 175                 ext4_warning(sb, "Cannot read last block (%llu)",
 176                              end - 1);
 177         } else if (outside(input->block_bitmap, start, end))
 178                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 179                              (unsigned long long)input->block_bitmap);
 180         else if (outside(input->inode_bitmap, start, end))
 181                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 182                              (unsigned long long)input->inode_bitmap);
 183         else if (outside(input->inode_table, start, end) ||
 184                  outside(itend - 1, start, end))
 185                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 186                              (unsigned long long)input->inode_table, itend - 1);
 187         else if (input->inode_bitmap == input->block_bitmap)
 188                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 189                              (unsigned long long)input->block_bitmap);
 190         else if (inside(input->block_bitmap, input->inode_table, itend))
 191                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 192                              "(%llu-%llu)",
 193                              (unsigned long long)input->block_bitmap,
 194                              (unsigned long long)input->inode_table, itend - 1);
 195         else if (inside(input->inode_bitmap, input->inode_table, itend))
 196                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 197                              "(%llu-%llu)",
 198                              (unsigned long long)input->inode_bitmap,
 199                              (unsigned long long)input->inode_table, itend - 1);
 200         else if (inside(input->block_bitmap, start, metaend))
 201                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 202                              (unsigned long long)input->block_bitmap,
 203                              start, metaend - 1);
 204         else if (inside(input->inode_bitmap, start, metaend))
 205                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 206                              (unsigned long long)input->inode_bitmap,
 207                              start, metaend - 1);
 208         else if (inside(input->inode_table, start, metaend) ||
 209                  inside(itend - 1, start, metaend))
 210                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 211                              "(%llu-%llu)",
 212                              (unsigned long long)input->inode_table,
 213                              itend - 1, start, metaend - 1);
 214         else
 215                 err = 0;
 216         brelse(bh);
 217
 218         return err;
 219 }
 220
 221 /*
 222  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 223  * group each time.
 224  */
 225 struct ext4_new_flex_group_data {
 226         struct ext4_new_group_data *groups;     /* new_group_data for groups
 227                                                    in the flex group */
 228         __u16 *bg_flags;                        /* block group flags of groups
 229                                                    in @groups */
 230         ext4_group_t resize_bg;                 /* number of allocated
 231                                                    new_group_data */
 232         ext4_group_t count;                     /* number of groups in @groups
 233                                                  */
 234 };
 235
 236 /*
 237  * Avoiding memory allocation failures due to too many groups added each time.
 238  */
 239 #define MAX_RESIZE_BG                           16384
 240
 241 /*
 242  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 243  * @flexbg_size.
 244  *
 245  * Returns NULL on failure otherwise address of the allocated structure.
 246  */
 247 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size)
 248 {
 249         struct ext4_new_flex_group_data *flex_gd;
 250
 251         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 252         if (flex_gd == NULL)
 253                 goto out3;
 254
 255         if (unlikely(flexbg_size > MAX_RESIZE_BG))
 256                 flex_gd->resize_bg = MAX_RESIZE_BG;
 257         else
 258                 flex_gd->resize_bg = flexbg_size;
 259
 260         flex_gd->groups = kmalloc_array(flex_gd->resize_bg,
 261                                         sizeof(struct ext4_new_group_data),
 262                                         GFP_NOFS);
 263         if (flex_gd->groups == NULL)
 264                 goto out2;
 265
 266         flex_gd->bg_flags = kmalloc_array(flex_gd->resize_bg, sizeof(__u16),
 267                                           GFP_NOFS);
 268         if (flex_gd->bg_flags == NULL)
 269                 goto out1;
 270
 271         return flex_gd;
 272
 273 out1:
 274         kfree(flex_gd->groups);
 275 out2:
 276         kfree(flex_gd);
 277 out3:
 278         return NULL;
 279 }
 280
 281 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 282 {
 283         kfree(flex_gd->bg_flags);
 284         kfree(flex_gd->groups);
 285         kfree(flex_gd);
 286 }
 287
 288 /*
 289  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 290  * and inode tables for a flex group.
 291  *
 292  * This function is used by 64bit-resize.  Note that this function allocates
 293  * group tables from the 1st group of groups contained by @flexgd, which may
 294  * be a partial of a flex group.
 295  *
 296  * @sb: super block of fs to which the groups belongs
 297  *
 298  * Returns 0 on a successful allocation of the metadata blocks in the
 299  * block group.
 300  */
 301 static int ext4_alloc_group_tables(struct super_block *sb,
 302                                 struct ext4_new_flex_group_data *flex_gd,
 303                                 unsigned int flexbg_size)
 304 {
 305         struct ext4_new_group_data *group_data = flex_gd->groups;
 306         ext4_fsblk_t start_blk;
 307         ext4_fsblk_t last_blk;
 308         ext4_group_t src_group;
 309         ext4_group_t bb_index = 0;
 310         ext4_group_t ib_index = 0;
 311         ext4_group_t it_index = 0;
 312         ext4_group_t group;
 313         ext4_group_t last_group;
 314         unsigned overhead;
 315         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 316         int i;
 317
 318         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 319
 320         src_group = group_data[0].group;
 321         last_group  = src_group + flex_gd->count - 1;
 322
 323         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 324                (last_group & ~(flexbg_size - 1))));
 325 next_group:
 326         group = group_data[0].group;
 327         if (src_group >= group_data[0].group + flex_gd->count)
 328                 return -ENOSPC;
 329         start_blk = ext4_group_first_block_no(sb, src_group);
 330         last_blk = start_blk + group_data[src_group - group].blocks_count;
 331
 332         overhead = ext4_group_overhead_blocks(sb, src_group);
 333
 334         start_blk += overhead;
 335
 336         /* We collect contiguous blocks as much as possible. */
 337         src_group++;
 338         for (; src_group <= last_group; src_group++) {
 339                 overhead = ext4_group_overhead_blocks(sb, src_group);
 340                 if (overhead == 0)
 341                         last_blk += group_data[src_group - group].blocks_count;
 342                 else
 343                         break;
 344         }
 345
 346         /* Allocate block bitmaps */
 347         for (; bb_index < flex_gd->count; bb_index++) {
 348                 if (start_blk >= last_blk)
 349                         goto next_group;
 350                 group_data[bb_index].block_bitmap = start_blk++;
 351                 group = ext4_get_group_number(sb, start_blk - 1);
 352                 group -= group_data[0].group;
 353                 group_data[group].mdata_blocks++;
 354                 flex_gd->bg_flags[group] &= uninit_mask;
 355         }
 356
 357         /* Allocate inode bitmaps */
 358         for (; ib_index < flex_gd->count; ib_index++) {
 359                 if (start_blk >= last_blk)
 360                         goto next_group;
 361                 group_data[ib_index].inode_bitmap = start_blk++;
 362                 group = ext4_get_group_number(sb, start_blk - 1);
 363                 group -= group_data[0].group;
 364                 group_data[group].mdata_blocks++;
 365                 flex_gd->bg_flags[group] &= uninit_mask;
 366         }
 367
 368         /* Allocate inode tables */
 369         for (; it_index < flex_gd->count; it_index++) {
 370                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 371                 ext4_fsblk_t next_group_start;
 372
 373                 if (start_blk + itb > last_blk)
 374                         goto next_group;
 375                 group_data[it_index].inode_table = start_blk;
 376                 group = ext4_get_group_number(sb, start_blk);
 377                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 378                 group -= group_data[0].group;
 379
 380                 if (start_blk + itb > next_group_start) {
 381                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 382                         overhead = start_blk + itb - next_group_start;
 383                         group_data[group + 1].mdata_blocks += overhead;
 384                         itb -= overhead;
 385                 }
 386
 387                 group_data[group].mdata_blocks += itb;
 388                 flex_gd->bg_flags[group] &= uninit_mask;
 389                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 390         }
 391
 392         /* Update free clusters count to exclude metadata blocks */
 393         for (i = 0; i < flex_gd->count; i++) {
 394                 group_data[i].free_clusters_count -=
 395                                 EXT4_NUM_B2C(EXT4_SB(sb),
 396                                              group_data[i].mdata_blocks);
 397         }
 398
 399         if (test_opt(sb, DEBUG)) {
 400                 int i;
 401                 group = group_data[0].group;
 402
 403                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 404                        "%u groups, flexbg size is %u:\n", flex_gd->count,
 405                        flexbg_size);
 406
 407                 for (i = 0; i < flex_gd->count; i++) {
 408                         ext4_debug(
 409                                "adding %s group %u: %u blocks (%u free, %u mdata blocks)\n",
 410                                ext4_bg_has_super(sb, group + i) ? "normal" :
 411                                "no-super", group + i,
 412                                group_data[i].blocks_count,
 413                                group_data[i].free_clusters_count,
 414                                group_data[i].mdata_blocks);
 415                 }
 416         }
 417         return 0;
 418 }
 419
 420 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 421                                   ext4_fsblk_t blk)
 422 {
 423         struct buffer_head *bh;
 424         int err;
 425
 426         bh = sb_getblk(sb, blk);
 427         if (unlikely(!bh))
 428                 return ERR_PTR(-ENOMEM);
 429         BUFFER_TRACE(bh, "get_write_access");
 430         if ((err = ext4_journal_get_write_access(handle, bh))) {
 431                 brelse(bh);
 432                 bh = ERR_PTR(err);
 433         } else {
 434                 memset(bh->b_data, 0, sb->s_blocksize);
 435                 set_buffer_uptodate(bh);
 436         }
 437
 438         return bh;
 439 }
 440
 441 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 442 {
 443         return ext4_journal_ensure_credits_fn(handle, credits,
 444                 EXT4_MAX_TRANS_DATA, 0, 0);
 445 }
 446
 447 /*
 448  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 449  *
 450  * Helper function for ext4_setup_new_group_blocks() which set .
 451  *
 452  * @sb: super block
 453  * @handle: journal handle
 454  * @flex_gd: flex group data
 455  */
 456 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 457                         struct ext4_new_flex_group_data *flex_gd,
 458                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 459 {
 460         struct ext4_sb_info *sbi = EXT4_SB(sb);
 461         ext4_group_t count = last_cluster - first_cluster + 1;
 462         ext4_group_t count2;
 463
 464         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 465                    last_cluster);
 466         for (count2 = count; count > 0;
 467              count -= count2, first_cluster += count2) {
 468                 ext4_fsblk_t start;
 469                 struct buffer_head *bh;
 470                 ext4_group_t group;
 471                 int err;
 472
 473                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 474                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 475                 group -= flex_gd->groups[0].group;
 476
 477                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 478                 if (count2 > count)
 479                         count2 = count;
 480
 481                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 482                         BUG_ON(flex_gd->count > 1);
 483                         continue;
 484                 }
 485
 486                 err = ext4_resize_ensure_credits_batch(handle, 1);
 487                 if (err < 0)
 488                         return err;
 489
 490                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 491                 if (unlikely(!bh))
 492                         return -ENOMEM;
 493
 494                 BUFFER_TRACE(bh, "get_write_access");
 495                 err = ext4_journal_get_write_access(handle, bh);
 496                 if (err) {
 497                         brelse(bh);
 498                         return err;
 499                 }
 500                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 501                            first_cluster, first_cluster - start, count2);
 502                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 503
 504                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 505                 brelse(bh);
 506                 if (unlikely(err))
 507                         return err;
 508         }
 509
 510         return 0;
 511 }
 512
 513 /*
 514  * Set up the block and inode bitmaps, and the inode table for the new groups.
 515  * This doesn't need to be part of the main transaction, since we are only
 516  * changing blocks outside the actual filesystem.  We still do journaling to
 517  * ensure the recovery is correct in case of a failure just after resize.
 518  * If any part of this fails, we simply abort the resize.
 519  *
 520  * setup_new_flex_group_blocks handles a flex group as follow:
 521  *  1. copy super block and GDT, and initialize group tables if necessary.
 522  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 523  *     super block and GDT.
 524  *  2. allocate group tables in block bitmaps, that is, set bits in block
 525  *     bitmap for blocks taken by group tables.
 526  */
 527 static int setup_new_flex_group_blocks(struct super_block *sb,
 528                                 struct ext4_new_flex_group_data *flex_gd)
 529 {
 530         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 531         ext4_fsblk_t start;
 532         ext4_fsblk_t block;
 533         struct ext4_sb_info *sbi = EXT4_SB(sb);
 534         struct ext4_super_block *es = sbi->s_es;
 535         struct ext4_new_group_data *group_data = flex_gd->groups;
 536         __u16 *bg_flags = flex_gd->bg_flags;
 537         handle_t *handle;
 538         ext4_group_t group, count;
 539         struct buffer_head *bh = NULL;
 540         int reserved_gdb, i, j, err = 0, err2;
 541         int meta_bg;
 542
 543         BUG_ON(!flex_gd->count || !group_data ||
 544                group_data[0].group != sbi->s_groups_count);
 545
 546         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 547         meta_bg = ext4_has_feature_meta_bg(sb);
 548
 549         /* This transaction may be extended/restarted along the way */
 550         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 551         if (IS_ERR(handle))
 552                 return PTR_ERR(handle);
 553
 554         group = group_data[0].group;
 555         for (i = 0; i < flex_gd->count; i++, group++) {
 556                 unsigned long gdblocks;
 557                 ext4_grpblk_t overhead;
 558
 559                 gdblocks = ext4_bg_num_gdb(sb, group);
 560                 start = ext4_group_first_block_no(sb, group);
 561
 562                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 563                         goto handle_itb;
 564
 565                 if (meta_bg == 1)
 566                         goto handle_itb;
 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, gdb);
 586                         if (err) {
 587                                 brelse(gdb);
 588                                 goto out;
 589                         }
 590                         memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
 591                                 s_group_desc, j)->b_data, gdb->b_size);
 592                         set_buffer_uptodate(gdb);
 593
 594                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 595                         if (unlikely(err)) {
 596                                 brelse(gdb);
 597                                 goto out;
 598                         }
 599                         brelse(gdb);
 600                 }
 601
 602                 /* Zero out all of the reserved backup group descriptor
 603                  * table blocks
 604                  */
 605                 if (ext4_bg_has_super(sb, group)) {
 606                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 607                                         reserved_gdb, GFP_NOFS);
 608                         if (err)
 609                                 goto out;
 610                 }
 611
 612 handle_itb:
 613                 /* Initialize group tables of the grop @group */
 614                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 615                         goto handle_bb;
 616
 617                 /* Zero out all of the inode table blocks */
 618                 block = group_data[i].inode_table;
 619                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 620                            block, sbi->s_itb_per_group);
 621                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 622                                        GFP_NOFS);
 623                 if (err)
 624                         goto out;
 625
 626 handle_bb:
 627                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 628                         goto handle_ib;
 629
 630                 /* Initialize block bitmap of the @group */
 631                 block = group_data[i].block_bitmap;
 632                 err = ext4_resize_ensure_credits_batch(handle, 1);
 633                 if (err < 0)
 634                         goto out;
 635
 636                 bh = bclean(handle, sb, block);
 637                 if (IS_ERR(bh)) {
 638                         err = PTR_ERR(bh);
 639                         goto out;
 640                 }
 641                 overhead = ext4_group_overhead_blocks(sb, group);
 642                 if (overhead != 0) {
 643                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 644                                    start);
 645                         ext4_set_bits(bh->b_data, 0,
 646                                       EXT4_NUM_B2C(sbi, overhead));
 647                 }
 648                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 649                                      sb->s_blocksize * 8, bh->b_data);
 650                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 651                 brelse(bh);
 652                 if (err)
 653                         goto out;
 654
 655 handle_ib:
 656                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 657                         continue;
 658
 659                 /* Initialize inode bitmap of the @group */
 660                 block = group_data[i].inode_bitmap;
 661                 err = ext4_resize_ensure_credits_batch(handle, 1);
 662                 if (err < 0)
 663                         goto out;
 664                 /* Mark unused entries in inode bitmap used */
 665                 bh = bclean(handle, sb, block);
 666                 if (IS_ERR(bh)) {
 667                         err = PTR_ERR(bh);
 668                         goto out;
 669                 }
 670
 671                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 672                                      sb->s_blocksize * 8, bh->b_data);
 673                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 674                 brelse(bh);
 675                 if (err)
 676                         goto out;
 677         }
 678
 679         /* Mark group tables in block bitmap */
 680         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 681                 count = group_table_count[j];
 682                 start = (&group_data[0].block_bitmap)[j];
 683                 block = start;
 684                 for (i = 1; i < flex_gd->count; i++) {
 685                         block += group_table_count[j];
 686                         if (block == (&group_data[i].block_bitmap)[j]) {
 687                                 count += group_table_count[j];
 688                                 continue;
 689                         }
 690                         err = set_flexbg_block_bitmap(sb, handle,
 691                                                       flex_gd,
 692                                                       EXT4_B2C(sbi, start),
 693                                                       EXT4_B2C(sbi,
 694                                                                start + count
 695                                                                - 1));
 696                         if (err)
 697                                 goto out;
 698                         count = group_table_count[j];
 699                         start = (&group_data[i].block_bitmap)[j];
 700                         block = start;
 701                 }
 702
 703                 if (count) {
 704                         err = set_flexbg_block_bitmap(sb, handle,
 705                                                       flex_gd,
 706                                                       EXT4_B2C(sbi, start),
 707                                                       EXT4_B2C(sbi,
 708                                                                start + count
 709                                                                - 1));
 710                         if (err)
 711                                 goto out;
 712                 }
 713         }
 714
 715 out:
 716         err2 = ext4_journal_stop(handle);
 717         if (err2 && !err)
 718                 err = err2;
 719
 720         return err;
 721 }
 722
 723 /*
 724  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 725  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 726  * calling this for the first time.  In a sparse filesystem it will be the
 727  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 728  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 729  */
 730 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 731                                   unsigned *five, unsigned *seven)
 732 {
 733         unsigned *min = three;
 734         int mult = 3;
 735         unsigned ret;
 736
 737         if (!ext4_has_feature_sparse_super(sb)) {
 738                 ret = *min;
 739                 *min += 1;
 740                 return ret;
 741         }
 742
 743         if (*five < *min) {
 744                 min = five;
 745                 mult = 5;
 746         }
 747         if (*seven < *min) {
 748                 min = seven;
 749                 mult = 7;
 750         }
 751
 752         ret = *min;
 753         *min *= mult;
 754
 755         return ret;
 756 }
 757
 758 /*
 759  * Check that all of the backup GDT blocks are held in the primary GDT block.
 760  * It is assumed that they are stored in group order.  Returns the number of
 761  * groups in current filesystem that have BACKUPS, or -ve error code.
 762  */
 763 static int verify_reserved_gdb(struct super_block *sb,
 764                                ext4_group_t end,
 765                                struct buffer_head *primary)
 766 {
 767         const ext4_fsblk_t blk = primary->b_blocknr;
 768         unsigned three = 1;
 769         unsigned five = 5;
 770         unsigned seven = 7;
 771         unsigned grp;
 772         __le32 *p = (__le32 *)primary->b_data;
 773         int gdbackups = 0;
 774
 775         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 776                 if (le32_to_cpu(*p++) !=
 777                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 778                         ext4_warning(sb, "reserved GDT %llu"
 779                                      " missing grp %d (%llu)",
 780                                      blk, grp,
 781                                      grp *
 782                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 783                                      blk);
 784                         return -EINVAL;
 785                 }
 786                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 787                         return -EFBIG;
 788         }
 789
 790         return gdbackups;
 791 }
 792
 793 /*
 794  * Called when we need to bring a reserved group descriptor table block into
 795  * use from the resize inode.  The primary copy of the new GDT block currently
 796  * is an indirect block (under the double indirect block in the resize inode).
 797  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 798  * block, in group order.  Even though we know all the block numbers we need,
 799  * we check to ensure that the resize inode has actually reserved these blocks.
 800  *
 801  * Don't need to update the block bitmaps because the blocks are still in use.
 802  *
 803  * We get all of the error cases out of the way, so that we are sure to not
 804  * fail once we start modifying the data on disk, because JBD has no rollback.
 805  */
 806 static int add_new_gdb(handle_t *handle, struct inode *inode,
 807                        ext4_group_t group)
 808 {
 809         struct super_block *sb = inode->i_sb;
 810         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 811         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 812         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 813         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 814         struct buffer_head *dind = NULL;
 815         struct buffer_head *gdb_bh = NULL;
 816         int gdbackups;
 817         struct ext4_iloc iloc = { .bh = NULL };
 818         __le32 *data;
 819         int err;
 820
 821         if (test_opt(sb, DEBUG))
 822                 printk(KERN_DEBUG
 823                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 824                        gdb_num);
 825
 826         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 827         if (IS_ERR(gdb_bh))
 828                 return PTR_ERR(gdb_bh);
 829
 830         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 831         if (gdbackups < 0) {
 832                 err = gdbackups;
 833                 goto errout;
 834         }
 835
 836         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 837         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 838         if (IS_ERR(dind)) {
 839                 err = PTR_ERR(dind);
 840                 dind = NULL;
 841                 goto errout;
 842         }
 843
 844         data = (__le32 *)dind->b_data;
 845         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 846                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 847                              group, gdblock);
 848                 err = -EINVAL;
 849                 goto errout;
 850         }
 851
 852         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 853         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 854         if (unlikely(err))
 855                 goto errout;
 856
 857         BUFFER_TRACE(gdb_bh, "get_write_access");
 858         err = ext4_journal_get_write_access(handle, gdb_bh);
 859         if (unlikely(err))
 860                 goto errout;
 861
 862         BUFFER_TRACE(dind, "get_write_access");
 863         err = ext4_journal_get_write_access(handle, dind);
 864         if (unlikely(err)) {
 865                 ext4_std_error(sb, err);
 866                 goto errout;
 867         }
 868
 869         /* ext4_reserve_inode_write() gets a reference on the iloc */
 870         err = ext4_reserve_inode_write(handle, inode, &iloc);
 871         if (unlikely(err))
 872                 goto errout;
 873
 874         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 875                                 GFP_KERNEL);
 876         if (!n_group_desc) {
 877                 err = -ENOMEM;
 878                 ext4_warning(sb, "not enough memory for %lu groups",
 879                              gdb_num + 1);
 880                 goto errout;
 881         }
 882
 883         /*
 884          * Finally, we have all of the possible failures behind us...
 885          *
 886          * Remove new GDT block from inode double-indirect block and clear out
 887          * the new GDT block for use (which also "frees" the backup GDT blocks
 888          * from the reserved inode).  We don't need to change the bitmaps for
 889          * these blocks, because they are marked as in-use from being in the
 890          * reserved inode, and will become GDT blocks (primary and backup).
 891          */
 892         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 893         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 894         if (unlikely(err)) {
 895                 ext4_std_error(sb, err);
 896                 goto errout;
 897         }
 898         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 899                            (9 - EXT4_SB(sb)->s_cluster_bits);
 900         ext4_mark_iloc_dirty(handle, inode, &iloc);
 901         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 902         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 903         if (unlikely(err)) {
 904                 ext4_std_error(sb, err);
 905                 iloc.bh = NULL;
 906                 goto errout;
 907         }
 908         brelse(dind);
 909
 910         rcu_read_lock();
 911         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 912         memcpy(n_group_desc, o_group_desc,
 913                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 914         rcu_read_unlock();
 915         n_group_desc[gdb_num] = gdb_bh;
 916         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 917         EXT4_SB(sb)->s_gdb_count++;
 918         ext4_kvfree_array_rcu(o_group_desc);
 919
 920         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 921         err = ext4_handle_dirty_super(handle, sb);
 922         if (err)
 923                 ext4_std_error(sb, err);
 924         return err;
 925 errout:
 926         kvfree(n_group_desc);
 927         brelse(iloc.bh);
 928         brelse(dind);
 929         brelse(gdb_bh);
 930
 931         ext4_debug("leaving with error %d\n", err);
 932         return err;
 933 }
 934
 935 /*
 936  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 937  */
 938 static int add_new_gdb_meta_bg(struct super_block *sb,
 939                                handle_t *handle, ext4_group_t group) {
 940         ext4_fsblk_t gdblock;
 941         struct buffer_head *gdb_bh;
 942         struct buffer_head **o_group_desc, **n_group_desc;
 943         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 944         int err;
 945
 946         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 947                    ext4_bg_has_super(sb, group);
 948         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 949         if (IS_ERR(gdb_bh))
 950                 return PTR_ERR(gdb_bh);
 951         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 952                                 GFP_KERNEL);
 953         if (!n_group_desc) {
 954                 brelse(gdb_bh);
 955                 err = -ENOMEM;
 956                 ext4_warning(sb, "not enough memory for %lu groups",
 957                              gdb_num + 1);
 958                 return err;
 959         }
 960
 961         rcu_read_lock();
 962         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 963         memcpy(n_group_desc, o_group_desc,
 964                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 965         rcu_read_unlock();
 966         n_group_desc[gdb_num] = gdb_bh;
 967
 968         BUFFER_TRACE(gdb_bh, "get_write_access");
 969         err = ext4_journal_get_write_access(handle, gdb_bh);
 970         if (err) {
 971                 kvfree(n_group_desc);
 972                 brelse(gdb_bh);
 973                 return err;
 974         }
 975
 976         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 977         EXT4_SB(sb)->s_gdb_count++;
 978         ext4_kvfree_array_rcu(o_group_desc);
 979         return err;
 980 }
 981
 982 /*
 983  * Called when we are adding a new group which has a backup copy of each of
 984  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 985  * We need to add these reserved backup GDT blocks to the resize inode, so
 986  * that they are kept for future resizing and not allocated to files.
 987  *
 988  * Each reserved backup GDT block will go into a different indirect block.
 989  * The indirect blocks are actually the primary reserved GDT blocks,
 990  * so we know in advance what their block numbers are.  We only get the
 991  * double-indirect block to verify it is pointing to the primary reserved
 992  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 993  * backup GDT blocks are stored in their reserved primary GDT block.
 994  */
 995 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 996                               ext4_group_t group)
 997 {
 998         struct super_block *sb = inode->i_sb;
 999         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1000         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1001         struct buffer_head **primary;
1002         struct buffer_head *dind;
1003         struct ext4_iloc iloc;
1004         ext4_fsblk_t blk;
1005         __le32 *data, *end;
1006         int gdbackups = 0;
1007         int res, i;
1008         int err;
1009
1010         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1011         if (!primary)
1012                 return -ENOMEM;
1013
1014         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1015         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1016         if (IS_ERR(dind)) {
1017                 err = PTR_ERR(dind);
1018                 dind = NULL;
1019                 goto exit_free;
1020         }
1021
1022         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1023         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1024                                          EXT4_ADDR_PER_BLOCK(sb));
1025         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1026
1027         /* Get each reserved primary GDT block and verify it holds backups */
1028         for (res = 0; res < reserved_gdb; res++, blk++) {
1029                 if (le32_to_cpu(*data) != blk) {
1030                         ext4_warning(sb, "reserved block %llu"
1031                                      " not at offset %ld",
1032                                      blk,
1033                                      (long)(data - (__le32 *)dind->b_data));
1034                         err = -EINVAL;
1035                         goto exit_bh;
1036                 }
1037                 primary[res] = ext4_sb_bread(sb, blk, 0);
1038                 if (IS_ERR(primary[res])) {
1039                         err = PTR_ERR(primary[res]);
1040                         primary[res] = NULL;
1041                         goto exit_bh;
1042                 }
1043                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1044                 if (gdbackups < 0) {
1045                         brelse(primary[res]);
1046                         err = gdbackups;
1047                         goto exit_bh;
1048                 }
1049                 if (++data >= end)
1050                         data = (__le32 *)dind->b_data;
1051         }
1052
1053         for (i = 0; i < reserved_gdb; i++) {
1054                 BUFFER_TRACE(primary[i], "get_write_access");
1055                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1056                         goto exit_bh;
1057         }
1058
1059         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1060                 goto exit_bh;
1061
1062         /*
1063          * Finally we can add each of the reserved backup GDT blocks from
1064          * the new group to its reserved primary GDT block.
1065          */
1066         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1067         for (i = 0; i < reserved_gdb; i++) {
1068                 int err2;
1069                 data = (__le32 *)primary[i]->b_data;
1070                 /* printk("reserving backup %lu[%u] = %lu\n",
1071                        primary[i]->b_blocknr, gdbackups,
1072                        blk + primary[i]->b_blocknr); */
1073                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1074                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1075                 if (!err)
1076                         err = err2;
1077         }
1078
1079         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1080         ext4_mark_iloc_dirty(handle, inode, &iloc);
1081
1082 exit_bh:
1083         while (--res >= 0)
1084                 brelse(primary[res]);
1085         brelse(dind);
1086
1087 exit_free:
1088         kfree(primary);
1089
1090         return err;
1091 }
1092
1093 /*
1094  * Update the backup copies of the ext4 metadata.  These don't need to be part
1095  * of the main resize transaction, because e2fsck will re-write them if there
1096  * is a problem (basically only OOM will cause a problem).  However, we
1097  * _should_ update the backups if possible, in case the primary gets trashed
1098  * for some reason and we need to run e2fsck from a backup superblock.  The
1099  * important part is that the new block and inode counts are in the backup
1100  * superblocks, and the location of the new group metadata in the GDT backups.
1101  *
1102  * We do not need take the s_resize_lock for this, because these
1103  * blocks are not otherwise touched by the filesystem code when it is
1104  * mounted.  We don't need to worry about last changing from
1105  * sbi->s_groups_count, because the worst that can happen is that we
1106  * do not copy the full number of backups at this time.  The resize
1107  * which changed s_groups_count will backup again.
1108  */
1109 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1110                            int size, int meta_bg)
1111 {
1112         struct ext4_sb_info *sbi = EXT4_SB(sb);
1113         ext4_group_t last;
1114         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1115         unsigned three = 1;
1116         unsigned five = 5;
1117         unsigned seven = 7;
1118         ext4_group_t group = 0;
1119         int rest = sb->s_blocksize - size;
1120         handle_t *handle;
1121         int err = 0, err2;
1122
1123         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1124         if (IS_ERR(handle)) {
1125                 group = 1;
1126                 err = PTR_ERR(handle);
1127                 goto exit_err;
1128         }
1129
1130         if (meta_bg == 0) {
1131                 group = ext4_list_backups(sb, &three, &five, &seven);
1132                 last = sbi->s_groups_count;
1133         } else {
1134                 group = ext4_get_group_number(sb, blk_off) + 1;
1135                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1136         }
1137
1138         while (group < sbi->s_groups_count) {
1139                 struct buffer_head *bh;
1140                 ext4_fsblk_t backup_block;
1141
1142                 /* Out of journal space, and can't get more - abort - so sad */
1143                 err = ext4_resize_ensure_credits_batch(handle, 1);
1144                 if (err < 0)
1145                         break;
1146
1147                 if (meta_bg == 0)
1148                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1149                 else
1150                         backup_block = (ext4_group_first_block_no(sb, group) +
1151                                         ext4_bg_has_super(sb, group));
1152
1153                 bh = sb_getblk(sb, backup_block);
1154                 if (unlikely(!bh)) {
1155                         err = -ENOMEM;
1156                         break;
1157                 }
1158                 ext4_debug("update metadata backup %llu(+%llu)\n",
1159                            backup_block, backup_block -
1160                            ext4_group_first_block_no(sb, group));
1161                 BUFFER_TRACE(bh, "get_write_access");
1162                 if ((err = ext4_journal_get_write_access(handle, bh))) {
1163                         brelse(bh);
1164                         break;
1165                 }
1166                 lock_buffer(bh);
1167                 memcpy(bh->b_data, data, size);
1168                 if (rest)
1169                         memset(bh->b_data + size, 0, rest);
1170                 set_buffer_uptodate(bh);
1171                 unlock_buffer(bh);
1172                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1173                 if (unlikely(err))
1174                         ext4_std_error(sb, err);
1175                 brelse(bh);
1176
1177                 if (meta_bg == 0)
1178                         group = ext4_list_backups(sb, &three, &five, &seven);
1179                 else if (group == last)
1180                         break;
1181                 else
1182                         group = last;
1183         }
1184         if ((err2 = ext4_journal_stop(handle)) && !err)
1185                 err = err2;
1186
1187         /*
1188          * Ugh! Need to have e2fsck write the backup copies.  It is too
1189          * late to revert the resize, we shouldn't fail just because of
1190          * the backup copies (they are only needed in case of corruption).
1191          *
1192          * However, if we got here we have a journal problem too, so we
1193          * can't really start a transaction to mark the superblock.
1194          * Chicken out and just set the flag on the hope it will be written
1195          * to disk, and if not - we will simply wait until next fsck.
1196          */
1197 exit_err:
1198         if (err) {
1199                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1200                              "forcing fsck on next reboot", group, err);
1201                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1202                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1203                 mark_buffer_dirty(sbi->s_sbh);
1204         }
1205 }
1206
1207 /*
1208  * ext4_add_new_descs() adds @count group descriptor of groups
1209  * starting at @group
1210  *
1211  * @handle: journal handle
1212  * @sb: super block
1213  * @group: the group no. of the first group desc to be added
1214  * @resize_inode: the resize inode
1215  * @count: number of group descriptors to be added
1216  */
1217 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1218                               ext4_group_t group, struct inode *resize_inode,
1219                               ext4_group_t count)
1220 {
1221         struct ext4_sb_info *sbi = EXT4_SB(sb);
1222         struct ext4_super_block *es = sbi->s_es;
1223         struct buffer_head *gdb_bh;
1224         int i, gdb_off, gdb_num, err = 0;
1225         int meta_bg;
1226
1227         meta_bg = ext4_has_feature_meta_bg(sb);
1228         for (i = 0; i < count; i++, group++) {
1229                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1230                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1231
1232                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1233                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1234
1235                 /*
1236                  * We will only either add reserved group blocks to a backup group
1237                  * or remove reserved blocks for the first group in a new group block.
1238                  * Doing both would be mean more complex code, and sane people don't
1239                  * use non-sparse filesystems anymore.  This is already checked above.
1240                  */
1241                 if (gdb_off) {
1242                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1243                                                      gdb_num);
1244                         BUFFER_TRACE(gdb_bh, "get_write_access");
1245                         err = ext4_journal_get_write_access(handle, gdb_bh);
1246
1247                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1248                                 err = reserve_backup_gdb(handle, resize_inode, group);
1249                 } else if (meta_bg != 0) {
1250                         err = add_new_gdb_meta_bg(sb, handle, group);
1251                 } else {
1252                         err = add_new_gdb(handle, resize_inode, group);
1253                 }
1254                 if (err)
1255                         break;
1256         }
1257         return err;
1258 }
1259
1260 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1261 {
1262         struct buffer_head *bh = sb_getblk(sb, block);
1263         if (unlikely(!bh))
1264                 return NULL;
1265         if (!bh_uptodate_or_lock(bh)) {
1266                 if (ext4_read_bh(bh, 0, NULL) < 0) {
1267                         brelse(bh);
1268                         return NULL;
1269                 }
1270         }
1271
1272         return bh;
1273 }
1274
1275 static int ext4_set_bitmap_checksums(struct super_block *sb,
1276                                      ext4_group_t group,
1277                                      struct ext4_group_desc *gdp,
1278                                      struct ext4_new_group_data *group_data)
1279 {
1280         struct buffer_head *bh;
1281
1282         if (!ext4_has_metadata_csum(sb))
1283                 return 0;
1284
1285         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1286         if (!bh)
1287                 return -EIO;
1288         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1289                                    EXT4_INODES_PER_GROUP(sb) / 8);
1290         brelse(bh);
1291
1292         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1293         if (!bh)
1294                 return -EIO;
1295         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1296         brelse(bh);
1297
1298         return 0;
1299 }
1300
1301 /*
1302  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1303  */
1304 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1305                                 struct ext4_new_flex_group_data *flex_gd)
1306 {
1307         struct ext4_new_group_data      *group_data = flex_gd->groups;
1308         struct ext4_group_desc          *gdp;
1309         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1310         struct buffer_head              *gdb_bh;
1311         ext4_group_t                    group;
1312         __u16                           *bg_flags = flex_gd->bg_flags;
1313         int                             i, gdb_off, gdb_num, err = 0;
1314
1315
1316         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1317                 group = group_data->group;
1318
1319                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1320                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1321
1322                 /*
1323                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1324                  */
1325                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1326                 /* Update group descriptor block for new group */
1327                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1328                                                  gdb_off * EXT4_DESC_SIZE(sb));
1329
1330                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1331                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1332                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1333                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1334                 if (err) {
1335                         ext4_std_error(sb, err);
1336                         break;
1337                 }
1338
1339                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1340                 ext4_free_group_clusters_set(sb, gdp,
1341                                              group_data->free_clusters_count);
1342                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1343                 if (ext4_has_group_desc_csum(sb))
1344                         ext4_itable_unused_set(sb, gdp,
1345                                                EXT4_INODES_PER_GROUP(sb));
1346                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1347                 ext4_group_desc_csum_set(sb, group, gdp);
1348
1349                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1350                 if (unlikely(err)) {
1351                         ext4_std_error(sb, err);
1352                         break;
1353                 }
1354
1355                 /*
1356                  * We can allocate memory for mb_alloc based on the new group
1357                  * descriptor
1358                  */
1359                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1360                 if (err)
1361                         break;
1362         }
1363         return err;
1364 }
1365
1366 /*
1367  * ext4_update_super() updates the super block so that the newly added
1368  * groups can be seen by the filesystem.
1369  *
1370  * @sb: super block
1371  * @flex_gd: new added groups
1372  */
1373 static void ext4_update_super(struct super_block *sb,
1374                              struct ext4_new_flex_group_data *flex_gd)
1375 {
1376         ext4_fsblk_t blocks_count = 0;
1377         ext4_fsblk_t free_blocks = 0;
1378         ext4_fsblk_t reserved_blocks = 0;
1379         struct ext4_new_group_data *group_data = flex_gd->groups;
1380         struct ext4_sb_info *sbi = EXT4_SB(sb);
1381         struct ext4_super_block *es = sbi->s_es;
1382         int i;
1383
1384         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1385         /*
1386          * Make the new blocks and inodes valid next.  We do this before
1387          * increasing the group count so that once the group is enabled,
1388          * all of its blocks and inodes are already valid.
1389          *
1390          * We always allocate group-by-group, then block-by-block or
1391          * inode-by-inode within a group, so enabling these
1392          * blocks/inodes before the group is live won't actually let us
1393          * allocate the new space yet.
1394          */
1395         for (i = 0; i < flex_gd->count; i++) {
1396                 blocks_count += group_data[i].blocks_count;
1397                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1398         }
1399
1400         reserved_blocks = ext4_r_blocks_count(es) * 100;
1401         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1402         reserved_blocks *= blocks_count;
1403         do_div(reserved_blocks, 100);
1404
1405         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1406         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1407         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1408                      flex_gd->count);
1409         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1410                      flex_gd->count);
1411
1412         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1413         /*
1414          * We need to protect s_groups_count against other CPUs seeing
1415          * inconsistent state in the superblock.
1416          *
1417          * The precise rules we use are:
1418          *
1419          * * Writers must perform a smp_wmb() after updating all
1420          *   dependent data and before modifying the groups count
1421          *
1422          * * Readers must perform an smp_rmb() after reading the groups
1423          *   count and before reading any dependent data.
1424          *
1425          * NB. These rules can be relaxed when checking the group count
1426          * while freeing data, as we can only allocate from a block
1427          * group after serialising against the group count, and we can
1428          * only then free after serialising in turn against that
1429          * allocation.
1430          */
1431         smp_wmb();
1432
1433         /* Update the global fs size fields */
1434         sbi->s_groups_count += flex_gd->count;
1435         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1436                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1437
1438         /* Update the reserved block counts only once the new group is
1439          * active. */
1440         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1441                                 reserved_blocks);
1442
1443         /* Update the free space counts */
1444         percpu_counter_add(&sbi->s_freeclusters_counter,
1445                            EXT4_NUM_B2C(sbi, free_blocks));
1446         percpu_counter_add(&sbi->s_freeinodes_counter,
1447                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1448
1449         ext4_debug("free blocks count %llu",
1450                    percpu_counter_read(&sbi->s_freeclusters_counter));
1451         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1452                 ext4_group_t flex_group;
1453                 struct flex_groups *fg;
1454
1455                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1456                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1457                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1458                              &fg->free_clusters);
1459                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1460                            &fg->free_inodes);
1461         }
1462
1463         /*
1464          * Update the fs overhead information
1465          */
1466         ext4_calculate_overhead(sb);
1467         es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1468
1469         if (test_opt(sb, DEBUG))
1470                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1471                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1472                        blocks_count, free_blocks, reserved_blocks);
1473 }
1474
1475 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1476  * _before_ we start modifying the filesystem, because we cannot abort the
1477  * transaction and not have it write the data to disk.
1478  */
1479 static int ext4_flex_group_add(struct super_block *sb,
1480                                struct inode *resize_inode,
1481                                struct ext4_new_flex_group_data *flex_gd)
1482 {
1483         struct ext4_sb_info *sbi = EXT4_SB(sb);
1484         struct ext4_super_block *es = sbi->s_es;
1485         ext4_fsblk_t o_blocks_count;
1486         ext4_grpblk_t last;
1487         ext4_group_t group;
1488         handle_t *handle;
1489         unsigned reserved_gdb;
1490         int err = 0, err2 = 0, credit;
1491
1492         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1493
1494         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1495         o_blocks_count = ext4_blocks_count(es);
1496         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1497         BUG_ON(last);
1498
1499         err = setup_new_flex_group_blocks(sb, flex_gd);
1500         if (err)
1501                 goto exit;
1502         /*
1503          * We will always be modifying at least the superblock and  GDT
1504          * blocks.  If we are adding a group past the last current GDT block,
1505          * we will also modify the inode and the dindirect block.  If we
1506          * are adding a group with superblock/GDT backups  we will also
1507          * modify each of the reserved GDT dindirect blocks.
1508          */
1509         credit = 3;     /* sb, resize inode, resize inode dindirect */
1510         /* GDT blocks */
1511         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1512         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1513         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1514         if (IS_ERR(handle)) {
1515                 err = PTR_ERR(handle);
1516                 goto exit;
1517         }
1518
1519         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1520         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1521         if (err)
1522                 goto exit_journal;
1523
1524         group = flex_gd->groups[0].group;
1525         BUG_ON(group != sbi->s_groups_count);
1526         err = ext4_add_new_descs(handle, sb, group,
1527                                 resize_inode, flex_gd->count);
1528         if (err)
1529                 goto exit_journal;
1530
1531         err = ext4_setup_new_descs(handle, sb, flex_gd);
1532         if (err)
1533                 goto exit_journal;
1534
1535         ext4_update_super(sb, flex_gd);
1536
1537         err = ext4_handle_dirty_super(handle, sb);
1538
1539 exit_journal:
1540         err2 = ext4_journal_stop(handle);
1541         if (!err)
1542                 err = err2;
1543
1544         if (!err) {
1545                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1546                 int gdb_num_end = ((group + flex_gd->count - 1) /
1547                                    EXT4_DESC_PER_BLOCK(sb));
1548                 int meta_bg = ext4_has_feature_meta_bg(sb) &&
1549                               gdb_num >= le32_to_cpu(es->s_first_meta_bg);
1550                 sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
1551                                          ext4_group_first_block_no(sb, 0);
1552                 sector_t old_gdb = 0;
1553
1554                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1555                                (char *)es, sizeof(struct ext4_super_block), 0);
1556                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1557                         struct buffer_head *gdb_bh;
1558
1559                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1560                                                      gdb_num);
1561                         if (old_gdb == gdb_bh->b_blocknr)
1562                                 continue;
1563                         update_backups(sb, gdb_bh->b_blocknr - padding_blocks,
1564                                        gdb_bh->b_data, gdb_bh->b_size, meta_bg);
1565                         old_gdb = gdb_bh->b_blocknr;
1566                 }
1567         }
1568 exit:
1569         return err;
1570 }
1571
1572 static int ext4_setup_next_flex_gd(struct super_block *sb,
1573                                     struct ext4_new_flex_group_data *flex_gd,
1574                                     ext4_fsblk_t n_blocks_count)
1575 {
1576         struct ext4_sb_info *sbi = EXT4_SB(sb);
1577         struct ext4_super_block *es = sbi->s_es;
1578         struct ext4_new_group_data *group_data = flex_gd->groups;
1579         ext4_fsblk_t o_blocks_count;
1580         ext4_group_t n_group;
1581         ext4_group_t group;
1582         ext4_group_t last_group;
1583         ext4_grpblk_t last;
1584         ext4_grpblk_t clusters_per_group;
1585         unsigned long i;
1586
1587         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1588
1589         o_blocks_count = ext4_blocks_count(es);
1590
1591         if (o_blocks_count == n_blocks_count)
1592                 return 0;
1593
1594         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1595         BUG_ON(last);
1596         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1597
1598         last_group = group | (flex_gd->resize_bg - 1);
1599         if (last_group > n_group)
1600                 last_group = n_group;
1601
1602         flex_gd->count = last_group - group + 1;
1603
1604         for (i = 0; i < flex_gd->count; i++) {
1605                 int overhead;
1606
1607                 group_data[i].group = group + i;
1608                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1609                 overhead = ext4_group_overhead_blocks(sb, group + i);
1610                 group_data[i].mdata_blocks = overhead;
1611                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1612                 if (ext4_has_group_desc_csum(sb)) {
1613                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1614                                                EXT4_BG_INODE_UNINIT;
1615                         if (!test_opt(sb, INIT_INODE_TABLE))
1616                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1617                 } else
1618                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1619         }
1620
1621         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1622                 /* We need to initialize block bitmap of last group. */
1623                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1624
1625         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1626                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1627                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1628                                                        last - 1;
1629         }
1630
1631         return 1;
1632 }
1633
1634 /* Add group descriptor data to an existing or new group descriptor block.
1635  * Ensure we handle all possible error conditions _before_ we start modifying
1636  * the filesystem, because we cannot abort the transaction and not have it
1637  * write the data to disk.
1638  *
1639  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1640  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1641  *
1642  * We only need to hold the superblock lock while we are actually adding
1643  * in the new group's counts to the superblock.  Prior to that we have
1644  * not really "added" the group at all.  We re-check that we are still
1645  * adding in the last group in case things have changed since verifying.
1646  */
1647 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1648 {
1649         struct ext4_new_flex_group_data flex_gd;
1650         struct ext4_sb_info *sbi = EXT4_SB(sb);
1651         struct ext4_super_block *es = sbi->s_es;
1652         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1653                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1654         struct inode *inode = NULL;
1655         int gdb_off;
1656         int err;
1657         __u16 bg_flags = 0;
1658
1659         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1660
1661         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1662                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1663                 return -EPERM;
1664         }
1665
1666         if (ext4_blocks_count(es) + input->blocks_count <
1667             ext4_blocks_count(es)) {
1668                 ext4_warning(sb, "blocks_count overflow");
1669                 return -EINVAL;
1670         }
1671
1672         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1673             le32_to_cpu(es->s_inodes_count)) {
1674                 ext4_warning(sb, "inodes_count overflow");
1675                 return -EINVAL;
1676         }
1677
1678         if (reserved_gdb || gdb_off == 0) {
1679                 if (!ext4_has_feature_resize_inode(sb) ||
1680                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1681                         ext4_warning(sb,
1682                                      "No reserved GDT blocks, can't resize");
1683                         return -EPERM;
1684                 }
1685                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1686                 if (IS_ERR(inode)) {
1687                         ext4_warning(sb, "Error opening resize inode");
1688                         return PTR_ERR(inode);
1689                 }
1690         }
1691
1692
1693         err = verify_group_input(sb, input);
1694         if (err)
1695                 goto out;
1696
1697         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1698         if (err)
1699                 goto out;
1700
1701         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1702         if (err)
1703                 goto out;
1704
1705         flex_gd.count = 1;
1706         flex_gd.groups = input;
1707         flex_gd.bg_flags = &bg_flags;
1708         err = ext4_flex_group_add(sb, inode, &flex_gd);
1709 out:
1710         iput(inode);
1711         return err;
1712 } /* ext4_group_add */
1713
1714 /*
1715  * extend a group without checking assuming that checking has been done.
1716  */
1717 static int ext4_group_extend_no_check(struct super_block *sb,
1718                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1719 {
1720         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1721         handle_t *handle;
1722         int err = 0, err2;
1723
1724         /* We will update the superblock, one block bitmap, and
1725          * one group descriptor via ext4_group_add_blocks().
1726          */
1727         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1728         if (IS_ERR(handle)) {
1729                 err = PTR_ERR(handle);
1730                 ext4_warning(sb, "error %d on journal start", err);
1731                 return err;
1732         }
1733
1734         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1735         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1736         if (err) {
1737                 ext4_warning(sb, "error %d on journal write access", err);
1738                 goto errout;
1739         }
1740
1741         ext4_blocks_count_set(es, o_blocks_count + add);
1742         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1743         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1744                    o_blocks_count + add);
1745         /* We add the blocks to the bitmap and set the group need init bit */
1746         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1747         if (err)
1748                 goto errout;
1749         ext4_handle_dirty_super(handle, sb);
1750         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1751                    o_blocks_count + add);
1752 errout:
1753         err2 = ext4_journal_stop(handle);
1754         if (err2 && !err)
1755                 err = err2;
1756
1757         if (!err) {
1758                 if (test_opt(sb, DEBUG))
1759                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1760                                "blocks\n", ext4_blocks_count(es));
1761                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1762                                (char *)es, sizeof(struct ext4_super_block), 0);
1763         }
1764         return err;
1765 }
1766
1767 /*
1768  * Extend the filesystem to the new number of blocks specified.  This entry
1769  * point is only used to extend the current filesystem to the end of the last
1770  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1771  * for emergencies (because it has no dependencies on reserved blocks).
1772  *
1773  * If we _really_ wanted, we could use default values to call ext4_group_add()
1774  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1775  * GDT blocks are reserved to grow to the desired size.
1776  */
1777 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1778                       ext4_fsblk_t n_blocks_count)
1779 {
1780         ext4_fsblk_t o_blocks_count;
1781         ext4_grpblk_t last;
1782         ext4_grpblk_t add;
1783         struct buffer_head *bh;
1784         int err;
1785         ext4_group_t group;
1786
1787         o_blocks_count = ext4_blocks_count(es);
1788
1789         if (test_opt(sb, DEBUG))
1790                 ext4_msg(sb, KERN_DEBUG,
1791                          "extending last group from %llu to %llu blocks",
1792                          o_blocks_count, n_blocks_count);
1793
1794         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1795                 return 0;
1796
1797         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1798                 ext4_msg(sb, KERN_ERR,
1799                          "filesystem too large to resize to %llu blocks safely",
1800                          n_blocks_count);
1801                 return -EINVAL;
1802         }
1803
1804         if (n_blocks_count < o_blocks_count) {
1805                 ext4_warning(sb, "can't shrink FS - resize aborted");
1806                 return -EINVAL;
1807         }
1808
1809         /* Handle the remaining blocks in the last group only. */
1810         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1811
1812         if (last == 0) {
1813                 ext4_warning(sb, "need to use ext2online to resize further");
1814                 return -EPERM;
1815         }
1816
1817         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1818
1819         if (o_blocks_count + add < o_blocks_count) {
1820                 ext4_warning(sb, "blocks_count overflow");
1821                 return -EINVAL;
1822         }
1823
1824         if (o_blocks_count + add > n_blocks_count)
1825                 add = n_blocks_count - o_blocks_count;
1826
1827         if (o_blocks_count + add < n_blocks_count)
1828                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1829                              o_blocks_count + add, add);
1830
1831         /* See if the device is actually as big as what was requested */
1832         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1833         if (IS_ERR(bh)) {
1834                 ext4_warning(sb, "can't read last block, resize aborted");
1835                 return -ENOSPC;
1836         }
1837         brelse(bh);
1838
1839         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1840         return err;
1841 } /* ext4_group_extend */
1842
1843
1844 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1845 {
1846         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1847 }
1848
1849 /*
1850  * Release the resize inode and drop the resize_inode feature if there
1851  * are no more reserved gdt blocks, and then convert the file system
1852  * to enable meta_bg
1853  */
1854 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1855 {
1856         handle_t *handle;
1857         struct ext4_sb_info *sbi = EXT4_SB(sb);
1858         struct ext4_super_block *es = sbi->s_es;
1859         struct ext4_inode_info *ei = EXT4_I(inode);
1860         ext4_fsblk_t nr;
1861         int i, ret, err = 0;
1862         int credits = 1;
1863
1864         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1865         if (inode) {
1866                 if (es->s_reserved_gdt_blocks) {
1867                         ext4_error(sb, "Unexpected non-zero "
1868                                    "s_reserved_gdt_blocks");
1869                         return -EPERM;
1870                 }
1871
1872                 /* Do a quick sanity check of the resize inode */
1873                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1874                                              (9 - sbi->s_cluster_bits)))
1875                         goto invalid_resize_inode;
1876                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1877                         if (i == EXT4_DIND_BLOCK) {
1878                                 if (ei->i_data[i])
1879                                         continue;
1880                                 else
1881                                         goto invalid_resize_inode;
1882                         }
1883                         if (ei->i_data[i])
1884                                 goto invalid_resize_inode;
1885                 }
1886                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1887         }
1888
1889         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1890         if (IS_ERR(handle))
1891                 return PTR_ERR(handle);
1892
1893         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1894         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1895         if (err)
1896                 goto errout;
1897
1898         ext4_clear_feature_resize_inode(sb);
1899         ext4_set_feature_meta_bg(sb);
1900         sbi->s_es->s_first_meta_bg =
1901                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1902
1903         err = ext4_handle_dirty_super(handle, sb);
1904         if (err) {
1905                 ext4_std_error(sb, err);
1906                 goto errout;
1907         }
1908
1909         if (inode) {
1910                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1911                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1912                                  EXT4_FREE_BLOCKS_METADATA |
1913                                  EXT4_FREE_BLOCKS_FORGET);
1914                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1915                 inode->i_blocks = 0;
1916
1917                 err = ext4_mark_inode_dirty(handle, inode);
1918                 if (err)
1919                         ext4_std_error(sb, err);
1920         }
1921
1922 errout:
1923         ret = ext4_journal_stop(handle);
1924         return err ? err : ret;
1925
1926 invalid_resize_inode:
1927         ext4_error(sb, "corrupted/inconsistent resize inode");
1928         return -EINVAL;
1929 }
1930
1931 /*
1932  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1933  *
1934  * @sb: super block of the fs to be resized
1935  * @n_blocks_count: the number of blocks resides in the resized fs
1936  */
1937 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1938 {
1939         struct ext4_new_flex_group_data *flex_gd = NULL;
1940         struct ext4_sb_info *sbi = EXT4_SB(sb);
1941         struct ext4_super_block *es = sbi->s_es;
1942         struct buffer_head *bh;
1943         struct inode *resize_inode = NULL;
1944         ext4_grpblk_t add, offset;
1945         unsigned long n_desc_blocks;
1946         unsigned long o_desc_blocks;
1947         ext4_group_t o_group;
1948         ext4_group_t n_group;
1949         ext4_fsblk_t o_blocks_count;
1950         ext4_fsblk_t n_blocks_count_retry = 0;
1951         unsigned long last_update_time = 0;
1952         int err = 0;
1953         int meta_bg;
1954         unsigned int flexbg_size = ext4_flex_bg_size(sbi);
1955
1956         /* See if the device is actually as big as what was requested */
1957         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
1958         if (IS_ERR(bh)) {
1959                 ext4_warning(sb, "can't read last block, resize aborted");
1960                 return -ENOSPC;
1961         }
1962         brelse(bh);
1963
1964         /*
1965          * For bigalloc, trim the requested size to the nearest cluster
1966          * boundary to avoid creating an unusable filesystem. We do this
1967          * silently, instead of returning an error, to avoid breaking
1968          * callers that blindly resize the filesystem to the full size of
1969          * the underlying block device.
1970          */
1971         if (ext4_has_feature_bigalloc(sb))
1972                 n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
1973
1974 retry:
1975         o_blocks_count = ext4_blocks_count(es);
1976
1977         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1978                  "to %llu blocks", o_blocks_count, n_blocks_count);
1979
1980         if (n_blocks_count < o_blocks_count) {
1981                 /* On-line shrinking not supported */
1982                 ext4_warning(sb, "can't shrink FS - resize aborted");
1983                 return -EINVAL;
1984         }
1985
1986         if (n_blocks_count == o_blocks_count)
1987                 /* Nothing need to do */
1988                 return 0;
1989
1990         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1991         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1992                 ext4_warning(sb, "resize would cause inodes_count overflow");
1993                 return -EINVAL;
1994         }
1995         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1996
1997         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1998         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1999
2000         meta_bg = ext4_has_feature_meta_bg(sb);
2001
2002         if (ext4_has_feature_resize_inode(sb)) {
2003                 if (meta_bg) {
2004                         ext4_error(sb, "resize_inode and meta_bg enabled "
2005                                    "simultaneously");
2006                         return -EINVAL;
2007                 }
2008                 if (n_desc_blocks > o_desc_blocks +
2009                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
2010                         n_blocks_count_retry = n_blocks_count;
2011                         n_desc_blocks = o_desc_blocks +
2012                                 le16_to_cpu(es->s_reserved_gdt_blocks);
2013                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2014                         n_blocks_count = (ext4_fsblk_t)n_group *
2015                                 EXT4_BLOCKS_PER_GROUP(sb) +
2016                                 le32_to_cpu(es->s_first_data_block);
2017                         n_group--; /* set to last group number */
2018                 }
2019
2020                 if (!resize_inode)
2021                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2022                                                  EXT4_IGET_SPECIAL);
2023                 if (IS_ERR(resize_inode)) {
2024                         ext4_warning(sb, "Error opening resize inode");
2025                         return PTR_ERR(resize_inode);
2026                 }
2027         }
2028
2029         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2030                 err = ext4_convert_meta_bg(sb, resize_inode);
2031                 if (err)
2032                         goto out;
2033                 if (resize_inode) {
2034                         iput(resize_inode);
2035                         resize_inode = NULL;
2036                 }
2037                 if (n_blocks_count_retry) {
2038                         n_blocks_count = n_blocks_count_retry;
2039                         n_blocks_count_retry = 0;
2040                         goto retry;
2041                 }
2042         }
2043
2044         /*
2045          * Make sure the last group has enough space so that it's
2046          * guaranteed to have enough space for all metadata blocks
2047          * that it might need to hold.  (We might not need to store
2048          * the inode table blocks in the last block group, but there
2049          * will be cases where this might be needed.)
2050          */
2051         if ((ext4_group_first_block_no(sb, n_group) +
2052              ext4_group_overhead_blocks(sb, n_group) + 2 +
2053              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2054                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2055                 n_group--;
2056                 n_blocks_count_retry = 0;
2057                 if (resize_inode) {
2058                         iput(resize_inode);
2059                         resize_inode = NULL;
2060                 }
2061                 goto retry;
2062         }
2063
2064         /* extend the last group */
2065         if (n_group == o_group)
2066                 add = n_blocks_count - o_blocks_count;
2067         else
2068                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2069         if (add > 0) {
2070                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2071                 if (err)
2072                         goto out;
2073         }
2074
2075         if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2076                 goto out;
2077
2078         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2079         if (err)
2080                 goto out;
2081
2082         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2083         if (err)
2084                 goto out;
2085
2086         flex_gd = alloc_flex_gd(flexbg_size);
2087         if (flex_gd == NULL) {
2088                 err = -ENOMEM;
2089                 goto out;
2090         }
2091
2092         /* Add flex groups. Note that a regular group is a
2093          * flex group with 1 group.
2094          */
2095         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count)) {
2096                 if (jiffies - last_update_time > HZ * 10) {
2097                         if (last_update_time)
2098                                 ext4_msg(sb, KERN_INFO,
2099                                          "resized to %llu blocks",
2100                                          ext4_blocks_count(es));
2101                         last_update_time = jiffies;
2102                 }
2103                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2104                         break;
2105                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2106                 if (unlikely(err))
2107                         break;
2108         }
2109
2110         if (!err && n_blocks_count_retry) {
2111                 n_blocks_count = n_blocks_count_retry;
2112                 n_blocks_count_retry = 0;
2113                 free_flex_gd(flex_gd);
2114                 flex_gd = NULL;
2115                 if (resize_inode) {
2116                         iput(resize_inode);
2117                         resize_inode = NULL;
2118                 }
2119                 goto retry;
2120         }
2121
2122 out:
2123         if (flex_gd)
2124                 free_flex_gd(flex_gd);
2125         if (resize_inode != NULL)
2126                 iput(resize_inode);
2127         if (err)
2128                 ext4_warning(sb, "error (%d) occurred during "
2129                              "file system resize", err);
2130         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2131                  ext4_blocks_count(es));
2132         return err;
2133 }