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 count;                     /* number of groups in @groups
 231                                                  */
 232 };
 233
 234 /*
 235  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 236  * @flexbg_size.
 237  *
 238  * Returns NULL on failure otherwise address of the allocated structure.
 239  */
 240 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 241 {
 242         struct ext4_new_flex_group_data *flex_gd;
 243
 244         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 245         if (flex_gd == NULL)
 246                 goto out3;
 247
 248         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 249                 goto out2;
 250         flex_gd->count = flexbg_size;
 251
 252         flex_gd->groups = kmalloc_array(flexbg_size,
 253                                         sizeof(struct ext4_new_group_data),
 254                                         GFP_NOFS);
 255         if (flex_gd->groups == NULL)
 256                 goto out2;
 257
 258         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 259                                           GFP_NOFS);
 260         if (flex_gd->bg_flags == NULL)
 261                 goto out1;
 262
 263         return flex_gd;
 264
 265 out1:
 266         kfree(flex_gd->groups);
 267 out2:
 268         kfree(flex_gd);
 269 out3:
 270         return NULL;
 271 }
 272
 273 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 274 {
 275         kfree(flex_gd->bg_flags);
 276         kfree(flex_gd->groups);
 277         kfree(flex_gd);
 278 }
 279
 280 /*
 281  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 282  * and inode tables for a flex group.
 283  *
 284  * This function is used by 64bit-resize.  Note that this function allocates
 285  * group tables from the 1st group of groups contained by @flexgd, which may
 286  * be a partial of a flex group.
 287  *
 288  * @sb: super block of fs to which the groups belongs
 289  *
 290  * Returns 0 on a successful allocation of the metadata blocks in the
 291  * block group.
 292  */
 293 static int ext4_alloc_group_tables(struct super_block *sb,
 294                                 struct ext4_new_flex_group_data *flex_gd,
 295                                 int flexbg_size)
 296 {
 297         struct ext4_new_group_data *group_data = flex_gd->groups;
 298         ext4_fsblk_t start_blk;
 299         ext4_fsblk_t last_blk;
 300         ext4_group_t src_group;
 301         ext4_group_t bb_index = 0;
 302         ext4_group_t ib_index = 0;
 303         ext4_group_t it_index = 0;
 304         ext4_group_t group;
 305         ext4_group_t last_group;
 306         unsigned overhead;
 307         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 308         int i;
 309
 310         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 311
 312         src_group = group_data[0].group;
 313         last_group  = src_group + flex_gd->count - 1;
 314
 315         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 316                (last_group & ~(flexbg_size - 1))));
 317 next_group:
 318         group = group_data[0].group;
 319         if (src_group >= group_data[0].group + flex_gd->count)
 320                 return -ENOSPC;
 321         start_blk = ext4_group_first_block_no(sb, src_group);
 322         last_blk = start_blk + group_data[src_group - group].blocks_count;
 323
 324         overhead = ext4_group_overhead_blocks(sb, src_group);
 325
 326         start_blk += overhead;
 327
 328         /* We collect contiguous blocks as much as possible. */
 329         src_group++;
 330         for (; src_group <= last_group; src_group++) {
 331                 overhead = ext4_group_overhead_blocks(sb, src_group);
 332                 if (overhead == 0)
 333                         last_blk += group_data[src_group - group].blocks_count;
 334                 else
 335                         break;
 336         }
 337
 338         /* Allocate block bitmaps */
 339         for (; bb_index < flex_gd->count; bb_index++) {
 340                 if (start_blk >= last_blk)
 341                         goto next_group;
 342                 group_data[bb_index].block_bitmap = start_blk++;
 343                 group = ext4_get_group_number(sb, start_blk - 1);
 344                 group -= group_data[0].group;
 345                 group_data[group].mdata_blocks++;
 346                 flex_gd->bg_flags[group] &= uninit_mask;
 347         }
 348
 349         /* Allocate inode bitmaps */
 350         for (; ib_index < flex_gd->count; ib_index++) {
 351                 if (start_blk >= last_blk)
 352                         goto next_group;
 353                 group_data[ib_index].inode_bitmap = start_blk++;
 354                 group = ext4_get_group_number(sb, start_blk - 1);
 355                 group -= group_data[0].group;
 356                 group_data[group].mdata_blocks++;
 357                 flex_gd->bg_flags[group] &= uninit_mask;
 358         }
 359
 360         /* Allocate inode tables */
 361         for (; it_index < flex_gd->count; it_index++) {
 362                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 363                 ext4_fsblk_t next_group_start;
 364
 365                 if (start_blk + itb > last_blk)
 366                         goto next_group;
 367                 group_data[it_index].inode_table = start_blk;
 368                 group = ext4_get_group_number(sb, start_blk);
 369                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 370                 group -= group_data[0].group;
 371
 372                 if (start_blk + itb > next_group_start) {
 373                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 374                         overhead = start_blk + itb - next_group_start;
 375                         group_data[group + 1].mdata_blocks += overhead;
 376                         itb -= overhead;
 377                 }
 378
 379                 group_data[group].mdata_blocks += itb;
 380                 flex_gd->bg_flags[group] &= uninit_mask;
 381                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 382         }
 383
 384         /* Update free clusters count to exclude metadata blocks */
 385         for (i = 0; i < flex_gd->count; i++) {
 386                 group_data[i].free_clusters_count -=
 387                                 EXT4_NUM_B2C(EXT4_SB(sb),
 388                                              group_data[i].mdata_blocks);
 389         }
 390
 391         if (test_opt(sb, DEBUG)) {
 392                 int i;
 393                 group = group_data[0].group;
 394
 395                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 396                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 397                        flexbg_size);
 398
 399                 for (i = 0; i < flex_gd->count; i++) {
 400                         ext4_debug(
 401                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 402                                ext4_bg_has_super(sb, group + i) ? "normal" :
 403                                "no-super", group + i,
 404                                group_data[i].blocks_count,
 405                                group_data[i].free_clusters_count,
 406                                group_data[i].mdata_blocks);
 407                 }
 408         }
 409         return 0;
 410 }
 411
 412 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 413                                   ext4_fsblk_t blk)
 414 {
 415         struct buffer_head *bh;
 416         int err;
 417
 418         bh = sb_getblk(sb, blk);
 419         if (unlikely(!bh))
 420                 return ERR_PTR(-ENOMEM);
 421         BUFFER_TRACE(bh, "get_write_access");
 422         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
 423         if (err) {
 424                 brelse(bh);
 425                 bh = ERR_PTR(err);
 426         } else {
 427                 memset(bh->b_data, 0, sb->s_blocksize);
 428                 set_buffer_uptodate(bh);
 429         }
 430
 431         return bh;
 432 }
 433
 434 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 435 {
 436         return ext4_journal_ensure_credits_fn(handle, credits,
 437                 EXT4_MAX_TRANS_DATA, 0, 0);
 438 }
 439
 440 /*
 441  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 442  *
 443  * Helper function for ext4_setup_new_group_blocks() which set .
 444  *
 445  * @sb: super block
 446  * @handle: journal handle
 447  * @flex_gd: flex group data
 448  */
 449 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 450                         struct ext4_new_flex_group_data *flex_gd,
 451                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 452 {
 453         struct ext4_sb_info *sbi = EXT4_SB(sb);
 454         ext4_group_t count = last_cluster - first_cluster + 1;
 455         ext4_group_t count2;
 456
 457         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 458                    last_cluster);
 459         for (count2 = count; count > 0;
 460              count -= count2, first_cluster += count2) {
 461                 ext4_fsblk_t start;
 462                 struct buffer_head *bh;
 463                 ext4_group_t group;
 464                 int err;
 465
 466                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 467                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 468                 group -= flex_gd->groups[0].group;
 469
 470                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 471                 if (count2 > count)
 472                         count2 = count;
 473
 474                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 475                         BUG_ON(flex_gd->count > 1);
 476                         continue;
 477                 }
 478
 479                 err = ext4_resize_ensure_credits_batch(handle, 1);
 480                 if (err < 0)
 481                         return err;
 482
 483                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 484                 if (unlikely(!bh))
 485                         return -ENOMEM;
 486
 487                 BUFFER_TRACE(bh, "get_write_access");
 488                 err = ext4_journal_get_write_access(handle, sb, bh,
 489                                                     EXT4_JTR_NONE);
 490                 if (err) {
 491                         brelse(bh);
 492                         return err;
 493                 }
 494                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 495                            first_cluster, first_cluster - start, count2);
 496                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 497
 498                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 499                 brelse(bh);
 500                 if (unlikely(err))
 501                         return err;
 502         }
 503
 504         return 0;
 505 }
 506
 507 /*
 508  * Set up the block and inode bitmaps, and the inode table for the new groups.
 509  * This doesn't need to be part of the main transaction, since we are only
 510  * changing blocks outside the actual filesystem.  We still do journaling to
 511  * ensure the recovery is correct in case of a failure just after resize.
 512  * If any part of this fails, we simply abort the resize.
 513  *
 514  * setup_new_flex_group_blocks handles a flex group as follow:
 515  *  1. copy super block and GDT, and initialize group tables if necessary.
 516  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 517  *     super block and GDT.
 518  *  2. allocate group tables in block bitmaps, that is, set bits in block
 519  *     bitmap for blocks taken by group tables.
 520  */
 521 static int setup_new_flex_group_blocks(struct super_block *sb,
 522                                 struct ext4_new_flex_group_data *flex_gd)
 523 {
 524         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 525         ext4_fsblk_t start;
 526         ext4_fsblk_t block;
 527         struct ext4_sb_info *sbi = EXT4_SB(sb);
 528         struct ext4_super_block *es = sbi->s_es;
 529         struct ext4_new_group_data *group_data = flex_gd->groups;
 530         __u16 *bg_flags = flex_gd->bg_flags;
 531         handle_t *handle;
 532         ext4_group_t group, count;
 533         struct buffer_head *bh = NULL;
 534         int reserved_gdb, i, j, err = 0, err2;
 535         int meta_bg;
 536
 537         BUG_ON(!flex_gd->count || !group_data ||
 538                group_data[0].group != sbi->s_groups_count);
 539
 540         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 541         meta_bg = ext4_has_feature_meta_bg(sb);
 542
 543         /* This transaction may be extended/restarted along the way */
 544         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 545         if (IS_ERR(handle))
 546                 return PTR_ERR(handle);
 547
 548         group = group_data[0].group;
 549         for (i = 0; i < flex_gd->count; i++, group++) {
 550                 unsigned long gdblocks;
 551                 ext4_grpblk_t overhead;
 552
 553                 gdblocks = ext4_bg_num_gdb(sb, group);
 554                 start = ext4_group_first_block_no(sb, group);
 555
 556                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 557                         goto handle_itb;
 558
 559                 if (meta_bg == 1) {
 560                         ext4_group_t first_group;
 561                         first_group = ext4_meta_bg_first_group(sb, group);
 562                         if (first_group != group + 1 &&
 563                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 564                                 goto handle_itb;
 565                 }
 566
 567                 block = start + ext4_bg_has_super(sb, group);
 568                 /* Copy all of the GDT blocks into the backup in this group */
 569                 for (j = 0; j < gdblocks; j++, block++) {
 570                         struct buffer_head *gdb;
 571
 572                         ext4_debug("update backup group %#04llx\n", block);
 573                         err = ext4_resize_ensure_credits_batch(handle, 1);
 574                         if (err < 0)
 575                                 goto out;
 576
 577                         gdb = sb_getblk(sb, block);
 578                         if (unlikely(!gdb)) {
 579                                 err = -ENOMEM;
 580                                 goto out;
 581                         }
 582
 583                         BUFFER_TRACE(gdb, "get_write_access");
 584                         err = ext4_journal_get_write_access(handle, sb, gdb,
 585                                                             EXT4_JTR_NONE);
 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, sb, EXT4_SB(sb)->s_sbh,
 854                                             EXT4_JTR_NONE);
 855         if (unlikely(err))
 856                 goto errout;
 857
 858         BUFFER_TRACE(gdb_bh, "get_write_access");
 859         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 860         if (unlikely(err))
 861                 goto errout;
 862
 863         BUFFER_TRACE(dind, "get_write_access");
 864         err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
 865         if (unlikely(err)) {
 866                 ext4_std_error(sb, err);
 867                 goto errout;
 868         }
 869
 870         /* ext4_reserve_inode_write() gets a reference on the iloc */
 871         err = ext4_reserve_inode_write(handle, inode, &iloc);
 872         if (unlikely(err))
 873                 goto errout;
 874
 875         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 876                                 GFP_KERNEL);
 877         if (!n_group_desc) {
 878                 err = -ENOMEM;
 879                 ext4_warning(sb, "not enough memory for %lu groups",
 880                              gdb_num + 1);
 881                 goto errout;
 882         }
 883
 884         /*
 885          * Finally, we have all of the possible failures behind us...
 886          *
 887          * Remove new GDT block from inode double-indirect block and clear out
 888          * the new GDT block for use (which also "frees" the backup GDT blocks
 889          * from the reserved inode).  We don't need to change the bitmaps for
 890          * these blocks, because they are marked as in-use from being in the
 891          * reserved inode, and will become GDT blocks (primary and backup).
 892          */
 893         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 894         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 895         if (unlikely(err)) {
 896                 ext4_std_error(sb, err);
 897                 goto errout;
 898         }
 899         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 900                            (9 - EXT4_SB(sb)->s_cluster_bits);
 901         ext4_mark_iloc_dirty(handle, inode, &iloc);
 902         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 903         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 904         if (unlikely(err)) {
 905                 ext4_std_error(sb, err);
 906                 iloc.bh = NULL;
 907                 goto errout;
 908         }
 909         brelse(dind);
 910
 911         rcu_read_lock();
 912         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 913         memcpy(n_group_desc, o_group_desc,
 914                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 915         rcu_read_unlock();
 916         n_group_desc[gdb_num] = gdb_bh;
 917         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 918         EXT4_SB(sb)->s_gdb_count++;
 919         ext4_kvfree_array_rcu(o_group_desc);
 920
 921         lock_buffer(EXT4_SB(sb)->s_sbh);
 922         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 923         ext4_superblock_csum_set(sb);
 924         unlock_buffer(EXT4_SB(sb)->s_sbh);
 925         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 926         if (err)
 927                 ext4_std_error(sb, err);
 928         return err;
 929 errout:
 930         kvfree(n_group_desc);
 931         brelse(iloc.bh);
 932         brelse(dind);
 933         brelse(gdb_bh);
 934
 935         ext4_debug("leaving with error %d\n", err);
 936         return err;
 937 }
 938
 939 /*
 940  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 941  */
 942 static int add_new_gdb_meta_bg(struct super_block *sb,
 943                                handle_t *handle, ext4_group_t group) {
 944         ext4_fsblk_t gdblock;
 945         struct buffer_head *gdb_bh;
 946         struct buffer_head **o_group_desc, **n_group_desc;
 947         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 948         int err;
 949
 950         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 951                    ext4_bg_has_super(sb, group);
 952         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 953         if (IS_ERR(gdb_bh))
 954                 return PTR_ERR(gdb_bh);
 955         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 956                                 GFP_KERNEL);
 957         if (!n_group_desc) {
 958                 brelse(gdb_bh);
 959                 err = -ENOMEM;
 960                 ext4_warning(sb, "not enough memory for %lu groups",
 961                              gdb_num + 1);
 962                 return err;
 963         }
 964
 965         rcu_read_lock();
 966         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 967         memcpy(n_group_desc, o_group_desc,
 968                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 969         rcu_read_unlock();
 970         n_group_desc[gdb_num] = gdb_bh;
 971
 972         BUFFER_TRACE(gdb_bh, "get_write_access");
 973         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 974         if (err) {
 975                 kvfree(n_group_desc);
 976                 brelse(gdb_bh);
 977                 return err;
 978         }
 979
 980         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 981         EXT4_SB(sb)->s_gdb_count++;
 982         ext4_kvfree_array_rcu(o_group_desc);
 983         return err;
 984 }
 985
 986 /*
 987  * Called when we are adding a new group which has a backup copy of each of
 988  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 989  * We need to add these reserved backup GDT blocks to the resize inode, so
 990  * that they are kept for future resizing and not allocated to files.
 991  *
 992  * Each reserved backup GDT block will go into a different indirect block.
 993  * The indirect blocks are actually the primary reserved GDT blocks,
 994  * so we know in advance what their block numbers are.  We only get the
 995  * double-indirect block to verify it is pointing to the primary reserved
 996  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 997  * backup GDT blocks are stored in their reserved primary GDT block.
 998  */
 999 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1000                               ext4_group_t group)
1001 {
1002         struct super_block *sb = inode->i_sb;
1003         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1004         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1005         struct buffer_head **primary;
1006         struct buffer_head *dind;
1007         struct ext4_iloc iloc;
1008         ext4_fsblk_t blk;
1009         __le32 *data, *end;
1010         int gdbackups = 0;
1011         int res, i;
1012         int err;
1013
1014         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1015         if (!primary)
1016                 return -ENOMEM;
1017
1018         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1019         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1020         if (IS_ERR(dind)) {
1021                 err = PTR_ERR(dind);
1022                 dind = NULL;
1023                 goto exit_free;
1024         }
1025
1026         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1027         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1028                                          EXT4_ADDR_PER_BLOCK(sb));
1029         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1030
1031         /* Get each reserved primary GDT block and verify it holds backups */
1032         for (res = 0; res < reserved_gdb; res++, blk++) {
1033                 if (le32_to_cpu(*data) != blk) {
1034                         ext4_warning(sb, "reserved block %llu"
1035                                      " not at offset %ld",
1036                                      blk,
1037                                      (long)(data - (__le32 *)dind->b_data));
1038                         err = -EINVAL;
1039                         goto exit_bh;
1040                 }
1041                 primary[res] = ext4_sb_bread(sb, blk, 0);
1042                 if (IS_ERR(primary[res])) {
1043                         err = PTR_ERR(primary[res]);
1044                         primary[res] = NULL;
1045                         goto exit_bh;
1046                 }
1047                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1048                 if (gdbackups < 0) {
1049                         brelse(primary[res]);
1050                         err = gdbackups;
1051                         goto exit_bh;
1052                 }
1053                 if (++data >= end)
1054                         data = (__le32 *)dind->b_data;
1055         }
1056
1057         for (i = 0; i < reserved_gdb; i++) {
1058                 BUFFER_TRACE(primary[i], "get_write_access");
1059                 if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1060                                                          EXT4_JTR_NONE)))
1061                         goto exit_bh;
1062         }
1063
1064         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1065                 goto exit_bh;
1066
1067         /*
1068          * Finally we can add each of the reserved backup GDT blocks from
1069          * the new group to its reserved primary GDT block.
1070          */
1071         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1072         for (i = 0; i < reserved_gdb; i++) {
1073                 int err2;
1074                 data = (__le32 *)primary[i]->b_data;
1075                 /* printk("reserving backup %lu[%u] = %lu\n",
1076                        primary[i]->b_blocknr, gdbackups,
1077                        blk + primary[i]->b_blocknr); */
1078                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1079                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1080                 if (!err)
1081                         err = err2;
1082         }
1083
1084         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1085         ext4_mark_iloc_dirty(handle, inode, &iloc);
1086
1087 exit_bh:
1088         while (--res >= 0)
1089                 brelse(primary[res]);
1090         brelse(dind);
1091
1092 exit_free:
1093         kfree(primary);
1094
1095         return err;
1096 }
1097
1098 /*
1099  * Update the backup copies of the ext4 metadata.  These don't need to be part
1100  * of the main resize transaction, because e2fsck will re-write them if there
1101  * is a problem (basically only OOM will cause a problem).  However, we
1102  * _should_ update the backups if possible, in case the primary gets trashed
1103  * for some reason and we need to run e2fsck from a backup superblock.  The
1104  * important part is that the new block and inode counts are in the backup
1105  * superblocks, and the location of the new group metadata in the GDT backups.
1106  *
1107  * We do not need take the s_resize_lock for this, because these
1108  * blocks are not otherwise touched by the filesystem code when it is
1109  * mounted.  We don't need to worry about last changing from
1110  * sbi->s_groups_count, because the worst that can happen is that we
1111  * do not copy the full number of backups at this time.  The resize
1112  * which changed s_groups_count will backup again.
1113  */
1114 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1115                            int size, int meta_bg)
1116 {
1117         struct ext4_sb_info *sbi = EXT4_SB(sb);
1118         ext4_group_t last;
1119         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1120         unsigned three = 1;
1121         unsigned five = 5;
1122         unsigned seven = 7;
1123         ext4_group_t group = 0;
1124         int rest = sb->s_blocksize - size;
1125         handle_t *handle;
1126         int err = 0, err2;
1127
1128         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1129         if (IS_ERR(handle)) {
1130                 group = 1;
1131                 err = PTR_ERR(handle);
1132                 goto exit_err;
1133         }
1134
1135         if (meta_bg == 0) {
1136                 group = ext4_list_backups(sb, &three, &five, &seven);
1137                 last = sbi->s_groups_count;
1138         } else {
1139                 group = ext4_get_group_number(sb, blk_off) + 1;
1140                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1141         }
1142
1143         while (group < sbi->s_groups_count) {
1144                 struct buffer_head *bh;
1145                 ext4_fsblk_t backup_block;
1146
1147                 /* Out of journal space, and can't get more - abort - so sad */
1148                 err = ext4_resize_ensure_credits_batch(handle, 1);
1149                 if (err < 0)
1150                         break;
1151
1152                 if (meta_bg == 0)
1153                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1154                 else
1155                         backup_block = (ext4_group_first_block_no(sb, group) +
1156                                         ext4_bg_has_super(sb, group));
1157
1158                 bh = sb_getblk(sb, backup_block);
1159                 if (unlikely(!bh)) {
1160                         err = -ENOMEM;
1161                         break;
1162                 }
1163                 ext4_debug("update metadata backup %llu(+%llu)\n",
1164                            backup_block, backup_block -
1165                            ext4_group_first_block_no(sb, group));
1166                 BUFFER_TRACE(bh, "get_write_access");
1167                 if ((err = ext4_journal_get_write_access(handle, sb, bh,
1168                                                          EXT4_JTR_NONE)))
1169                         break;
1170                 lock_buffer(bh);
1171                 memcpy(bh->b_data, data, size);
1172                 if (rest)
1173                         memset(bh->b_data + size, 0, rest);
1174                 set_buffer_uptodate(bh);
1175                 unlock_buffer(bh);
1176                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1177                 if (unlikely(err))
1178                         ext4_std_error(sb, err);
1179                 brelse(bh);
1180
1181                 if (meta_bg == 0)
1182                         group = ext4_list_backups(sb, &three, &five, &seven);
1183                 else if (group == last)
1184                         break;
1185                 else
1186                         group = last;
1187         }
1188         if ((err2 = ext4_journal_stop(handle)) && !err)
1189                 err = err2;
1190
1191         /*
1192          * Ugh! Need to have e2fsck write the backup copies.  It is too
1193          * late to revert the resize, we shouldn't fail just because of
1194          * the backup copies (they are only needed in case of corruption).
1195          *
1196          * However, if we got here we have a journal problem too, so we
1197          * can't really start a transaction to mark the superblock.
1198          * Chicken out and just set the flag on the hope it will be written
1199          * to disk, and if not - we will simply wait until next fsck.
1200          */
1201 exit_err:
1202         if (err) {
1203                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1204                              "forcing fsck on next reboot", group, err);
1205                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1206                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1207                 mark_buffer_dirty(sbi->s_sbh);
1208         }
1209 }
1210
1211 /*
1212  * ext4_add_new_descs() adds @count group descriptor of groups
1213  * starting at @group
1214  *
1215  * @handle: journal handle
1216  * @sb: super block
1217  * @group: the group no. of the first group desc to be added
1218  * @resize_inode: the resize inode
1219  * @count: number of group descriptors to be added
1220  */
1221 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1222                               ext4_group_t group, struct inode *resize_inode,
1223                               ext4_group_t count)
1224 {
1225         struct ext4_sb_info *sbi = EXT4_SB(sb);
1226         struct ext4_super_block *es = sbi->s_es;
1227         struct buffer_head *gdb_bh;
1228         int i, gdb_off, gdb_num, err = 0;
1229         int meta_bg;
1230
1231         meta_bg = ext4_has_feature_meta_bg(sb);
1232         for (i = 0; i < count; i++, group++) {
1233                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1234                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1235
1236                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1237                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1238
1239                 /*
1240                  * We will only either add reserved group blocks to a backup group
1241                  * or remove reserved blocks for the first group in a new group block.
1242                  * Doing both would be mean more complex code, and sane people don't
1243                  * use non-sparse filesystems anymore.  This is already checked above.
1244                  */
1245                 if (gdb_off) {
1246                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1247                                                      gdb_num);
1248                         BUFFER_TRACE(gdb_bh, "get_write_access");
1249                         err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1250                                                             EXT4_JTR_NONE);
1251
1252                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1253                                 err = reserve_backup_gdb(handle, resize_inode, group);
1254                 } else if (meta_bg != 0) {
1255                         err = add_new_gdb_meta_bg(sb, handle, group);
1256                 } else {
1257                         err = add_new_gdb(handle, resize_inode, group);
1258                 }
1259                 if (err)
1260                         break;
1261         }
1262         return err;
1263 }
1264
1265 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1266 {
1267         struct buffer_head *bh = sb_getblk(sb, block);
1268         if (unlikely(!bh))
1269                 return NULL;
1270         if (!bh_uptodate_or_lock(bh)) {
1271                 if (ext4_read_bh(bh, 0, NULL) < 0) {
1272                         brelse(bh);
1273                         return NULL;
1274                 }
1275         }
1276
1277         return bh;
1278 }
1279
1280 static int ext4_set_bitmap_checksums(struct super_block *sb,
1281                                      ext4_group_t group,
1282                                      struct ext4_group_desc *gdp,
1283                                      struct ext4_new_group_data *group_data)
1284 {
1285         struct buffer_head *bh;
1286
1287         if (!ext4_has_metadata_csum(sb))
1288                 return 0;
1289
1290         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1291         if (!bh)
1292                 return -EIO;
1293         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1294                                    EXT4_INODES_PER_GROUP(sb) / 8);
1295         brelse(bh);
1296
1297         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1298         if (!bh)
1299                 return -EIO;
1300         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1301         brelse(bh);
1302
1303         return 0;
1304 }
1305
1306 /*
1307  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1308  */
1309 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1310                                 struct ext4_new_flex_group_data *flex_gd)
1311 {
1312         struct ext4_new_group_data      *group_data = flex_gd->groups;
1313         struct ext4_group_desc          *gdp;
1314         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1315         struct buffer_head              *gdb_bh;
1316         ext4_group_t                    group;
1317         __u16                           *bg_flags = flex_gd->bg_flags;
1318         int                             i, gdb_off, gdb_num, err = 0;
1319
1320
1321         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1322                 group = group_data->group;
1323
1324                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1325                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1326
1327                 /*
1328                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1329                  */
1330                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1331                 /* Update group descriptor block for new group */
1332                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1333                                                  gdb_off * EXT4_DESC_SIZE(sb));
1334
1335                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1336                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1337                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1338                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1339                 if (err) {
1340                         ext4_std_error(sb, err);
1341                         break;
1342                 }
1343
1344                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1345                 ext4_free_group_clusters_set(sb, gdp,
1346                                              group_data->free_clusters_count);
1347                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1348                 if (ext4_has_group_desc_csum(sb))
1349                         ext4_itable_unused_set(sb, gdp,
1350                                                EXT4_INODES_PER_GROUP(sb));
1351                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1352                 ext4_group_desc_csum_set(sb, group, gdp);
1353
1354                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1355                 if (unlikely(err)) {
1356                         ext4_std_error(sb, err);
1357                         break;
1358                 }
1359
1360                 /*
1361                  * We can allocate memory for mb_alloc based on the new group
1362                  * descriptor
1363                  */
1364                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1365                 if (err)
1366                         break;
1367         }
1368         return err;
1369 }
1370
1371 /*
1372  * ext4_update_super() updates the super block so that the newly added
1373  * groups can be seen by the filesystem.
1374  *
1375  * @sb: super block
1376  * @flex_gd: new added groups
1377  */
1378 static void ext4_update_super(struct super_block *sb,
1379                              struct ext4_new_flex_group_data *flex_gd)
1380 {
1381         ext4_fsblk_t blocks_count = 0;
1382         ext4_fsblk_t free_blocks = 0;
1383         ext4_fsblk_t reserved_blocks = 0;
1384         struct ext4_new_group_data *group_data = flex_gd->groups;
1385         struct ext4_sb_info *sbi = EXT4_SB(sb);
1386         struct ext4_super_block *es = sbi->s_es;
1387         int i;
1388
1389         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1390         /*
1391          * Make the new blocks and inodes valid next.  We do this before
1392          * increasing the group count so that once the group is enabled,
1393          * all of its blocks and inodes are already valid.
1394          *
1395          * We always allocate group-by-group, then block-by-block or
1396          * inode-by-inode within a group, so enabling these
1397          * blocks/inodes before the group is live won't actually let us
1398          * allocate the new space yet.
1399          */
1400         for (i = 0; i < flex_gd->count; i++) {
1401                 blocks_count += group_data[i].blocks_count;
1402                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1403         }
1404
1405         reserved_blocks = ext4_r_blocks_count(es) * 100;
1406         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1407         reserved_blocks *= blocks_count;
1408         do_div(reserved_blocks, 100);
1409
1410         lock_buffer(sbi->s_sbh);
1411         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1412         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1413         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1414                      flex_gd->count);
1415         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1416                      flex_gd->count);
1417
1418         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1419         /*
1420          * We need to protect s_groups_count against other CPUs seeing
1421          * inconsistent state in the superblock.
1422          *
1423          * The precise rules we use are:
1424          *
1425          * * Writers must perform a smp_wmb() after updating all
1426          *   dependent data and before modifying the groups count
1427          *
1428          * * Readers must perform an smp_rmb() after reading the groups
1429          *   count and before reading any dependent data.
1430          *
1431          * NB. These rules can be relaxed when checking the group count
1432          * while freeing data, as we can only allocate from a block
1433          * group after serialising against the group count, and we can
1434          * only then free after serialising in turn against that
1435          * allocation.
1436          */
1437         smp_wmb();
1438
1439         /* Update the global fs size fields */
1440         sbi->s_groups_count += flex_gd->count;
1441         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1442                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1443
1444         /* Update the reserved block counts only once the new group is
1445          * active. */
1446         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1447                                 reserved_blocks);
1448
1449         /* Update the free space counts */
1450         percpu_counter_add(&sbi->s_freeclusters_counter,
1451                            EXT4_NUM_B2C(sbi, free_blocks));
1452         percpu_counter_add(&sbi->s_freeinodes_counter,
1453                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1454
1455         ext4_debug("free blocks count %llu",
1456                    percpu_counter_read(&sbi->s_freeclusters_counter));
1457         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1458                 ext4_group_t flex_group;
1459                 struct flex_groups *fg;
1460
1461                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1462                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1463                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1464                              &fg->free_clusters);
1465                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1466                            &fg->free_inodes);
1467         }
1468
1469         /*
1470          * Update the fs overhead information
1471          */
1472         ext4_calculate_overhead(sb);
1473         es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1474
1475         ext4_superblock_csum_set(sb);
1476         unlock_buffer(sbi->s_sbh);
1477         if (test_opt(sb, DEBUG))
1478                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1479                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1480                        blocks_count, free_blocks, reserved_blocks);
1481 }
1482
1483 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1484  * _before_ we start modifying the filesystem, because we cannot abort the
1485  * transaction and not have it write the data to disk.
1486  */
1487 static int ext4_flex_group_add(struct super_block *sb,
1488                                struct inode *resize_inode,
1489                                struct ext4_new_flex_group_data *flex_gd)
1490 {
1491         struct ext4_sb_info *sbi = EXT4_SB(sb);
1492         struct ext4_super_block *es = sbi->s_es;
1493         ext4_fsblk_t o_blocks_count;
1494         ext4_grpblk_t last;
1495         ext4_group_t group;
1496         handle_t *handle;
1497         unsigned reserved_gdb;
1498         int err = 0, err2 = 0, credit;
1499
1500         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1501
1502         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1503         o_blocks_count = ext4_blocks_count(es);
1504         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1505         BUG_ON(last);
1506
1507         err = setup_new_flex_group_blocks(sb, flex_gd);
1508         if (err)
1509                 goto exit;
1510         /*
1511          * We will always be modifying at least the superblock and  GDT
1512          * blocks.  If we are adding a group past the last current GDT block,
1513          * we will also modify the inode and the dindirect block.  If we
1514          * are adding a group with superblock/GDT backups  we will also
1515          * modify each of the reserved GDT dindirect blocks.
1516          */
1517         credit = 3;     /* sb, resize inode, resize inode dindirect */
1518         /* GDT blocks */
1519         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1520         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1521         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1522         if (IS_ERR(handle)) {
1523                 err = PTR_ERR(handle);
1524                 goto exit;
1525         }
1526
1527         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1528         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1529                                             EXT4_JTR_NONE);
1530         if (err)
1531                 goto exit_journal;
1532
1533         group = flex_gd->groups[0].group;
1534         BUG_ON(group != sbi->s_groups_count);
1535         err = ext4_add_new_descs(handle, sb, group,
1536                                 resize_inode, flex_gd->count);
1537         if (err)
1538                 goto exit_journal;
1539
1540         err = ext4_setup_new_descs(handle, sb, flex_gd);
1541         if (err)
1542                 goto exit_journal;
1543
1544         ext4_update_super(sb, flex_gd);
1545
1546         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1547
1548 exit_journal:
1549         err2 = ext4_journal_stop(handle);
1550         if (!err)
1551                 err = err2;
1552
1553         if (!err) {
1554                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1555                 int gdb_num_end = ((group + flex_gd->count - 1) /
1556                                    EXT4_DESC_PER_BLOCK(sb));
1557                 int meta_bg = ext4_has_feature_meta_bg(sb);
1558                 sector_t old_gdb = 0;
1559
1560                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1561                                (char *)es, sizeof(struct ext4_super_block), 0);
1562                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1563                         struct buffer_head *gdb_bh;
1564
1565                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1566                                                      gdb_num);
1567                         if (old_gdb == gdb_bh->b_blocknr)
1568                                 continue;
1569                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1570                                        gdb_bh->b_size, meta_bg);
1571                         old_gdb = gdb_bh->b_blocknr;
1572                 }
1573         }
1574 exit:
1575         return err;
1576 }
1577
1578 static int ext4_setup_next_flex_gd(struct super_block *sb,
1579                                     struct ext4_new_flex_group_data *flex_gd,
1580                                     ext4_fsblk_t n_blocks_count,
1581                                     unsigned long flexbg_size)
1582 {
1583         struct ext4_sb_info *sbi = EXT4_SB(sb);
1584         struct ext4_super_block *es = sbi->s_es;
1585         struct ext4_new_group_data *group_data = flex_gd->groups;
1586         ext4_fsblk_t o_blocks_count;
1587         ext4_group_t n_group;
1588         ext4_group_t group;
1589         ext4_group_t last_group;
1590         ext4_grpblk_t last;
1591         ext4_grpblk_t clusters_per_group;
1592         unsigned long i;
1593
1594         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1595
1596         o_blocks_count = ext4_blocks_count(es);
1597
1598         if (o_blocks_count == n_blocks_count)
1599                 return 0;
1600
1601         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1602         BUG_ON(last);
1603         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1604
1605         last_group = group | (flexbg_size - 1);
1606         if (last_group > n_group)
1607                 last_group = n_group;
1608
1609         flex_gd->count = last_group - group + 1;
1610
1611         for (i = 0; i < flex_gd->count; i++) {
1612                 int overhead;
1613
1614                 group_data[i].group = group + i;
1615                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1616                 overhead = ext4_group_overhead_blocks(sb, group + i);
1617                 group_data[i].mdata_blocks = overhead;
1618                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1619                 if (ext4_has_group_desc_csum(sb)) {
1620                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1621                                                EXT4_BG_INODE_UNINIT;
1622                         if (!test_opt(sb, INIT_INODE_TABLE))
1623                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1624                 } else
1625                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1626         }
1627
1628         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1629                 /* We need to initialize block bitmap of last group. */
1630                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1631
1632         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1633                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1634                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1635                                                        last - 1;
1636         }
1637
1638         return 1;
1639 }
1640
1641 /* Add group descriptor data to an existing or new group descriptor block.
1642  * Ensure we handle all possible error conditions _before_ we start modifying
1643  * the filesystem, because we cannot abort the transaction and not have it
1644  * write the data to disk.
1645  *
1646  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1647  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1648  *
1649  * We only need to hold the superblock lock while we are actually adding
1650  * in the new group's counts to the superblock.  Prior to that we have
1651  * not really "added" the group at all.  We re-check that we are still
1652  * adding in the last group in case things have changed since verifying.
1653  */
1654 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1655 {
1656         struct ext4_new_flex_group_data flex_gd;
1657         struct ext4_sb_info *sbi = EXT4_SB(sb);
1658         struct ext4_super_block *es = sbi->s_es;
1659         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1660                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1661         struct inode *inode = NULL;
1662         int gdb_off;
1663         int err;
1664         __u16 bg_flags = 0;
1665
1666         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1667
1668         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1669                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1670                 return -EPERM;
1671         }
1672
1673         if (ext4_blocks_count(es) + input->blocks_count <
1674             ext4_blocks_count(es)) {
1675                 ext4_warning(sb, "blocks_count overflow");
1676                 return -EINVAL;
1677         }
1678
1679         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1680             le32_to_cpu(es->s_inodes_count)) {
1681                 ext4_warning(sb, "inodes_count overflow");
1682                 return -EINVAL;
1683         }
1684
1685         if (reserved_gdb || gdb_off == 0) {
1686                 if (!ext4_has_feature_resize_inode(sb) ||
1687                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1688                         ext4_warning(sb,
1689                                      "No reserved GDT blocks, can't resize");
1690                         return -EPERM;
1691                 }
1692                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1693                 if (IS_ERR(inode)) {
1694                         ext4_warning(sb, "Error opening resize inode");
1695                         return PTR_ERR(inode);
1696                 }
1697         }
1698
1699
1700         err = verify_group_input(sb, input);
1701         if (err)
1702                 goto out;
1703
1704         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1705         if (err)
1706                 goto out;
1707
1708         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1709         if (err)
1710                 goto out;
1711
1712         flex_gd.count = 1;
1713         flex_gd.groups = input;
1714         flex_gd.bg_flags = &bg_flags;
1715         err = ext4_flex_group_add(sb, inode, &flex_gd);
1716 out:
1717         iput(inode);
1718         return err;
1719 } /* ext4_group_add */
1720
1721 /*
1722  * extend a group without checking assuming that checking has been done.
1723  */
1724 static int ext4_group_extend_no_check(struct super_block *sb,
1725                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1726 {
1727         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1728         handle_t *handle;
1729         int err = 0, err2;
1730
1731         /* We will update the superblock, one block bitmap, and
1732          * one group descriptor via ext4_group_add_blocks().
1733          */
1734         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1735         if (IS_ERR(handle)) {
1736                 err = PTR_ERR(handle);
1737                 ext4_warning(sb, "error %d on journal start", err);
1738                 return err;
1739         }
1740
1741         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1742         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1743                                             EXT4_JTR_NONE);
1744         if (err) {
1745                 ext4_warning(sb, "error %d on journal write access", err);
1746                 goto errout;
1747         }
1748
1749         lock_buffer(EXT4_SB(sb)->s_sbh);
1750         ext4_blocks_count_set(es, o_blocks_count + add);
1751         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1752         ext4_superblock_csum_set(sb);
1753         unlock_buffer(EXT4_SB(sb)->s_sbh);
1754         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1755                    o_blocks_count + add);
1756         /* We add the blocks to the bitmap and set the group need init bit */
1757         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1758         if (err)
1759                 goto errout;
1760         ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1761         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1762                    o_blocks_count + add);
1763 errout:
1764         err2 = ext4_journal_stop(handle);
1765         if (err2 && !err)
1766                 err = err2;
1767
1768         if (!err) {
1769                 if (test_opt(sb, DEBUG))
1770                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1771                                "blocks\n", ext4_blocks_count(es));
1772                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1773                                (char *)es, sizeof(struct ext4_super_block), 0);
1774         }
1775         return err;
1776 }
1777
1778 /*
1779  * Extend the filesystem to the new number of blocks specified.  This entry
1780  * point is only used to extend the current filesystem to the end of the last
1781  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1782  * for emergencies (because it has no dependencies on reserved blocks).
1783  *
1784  * If we _really_ wanted, we could use default values to call ext4_group_add()
1785  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1786  * GDT blocks are reserved to grow to the desired size.
1787  */
1788 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1789                       ext4_fsblk_t n_blocks_count)
1790 {
1791         ext4_fsblk_t o_blocks_count;
1792         ext4_grpblk_t last;
1793         ext4_grpblk_t add;
1794         struct buffer_head *bh;
1795         int err;
1796         ext4_group_t group;
1797
1798         o_blocks_count = ext4_blocks_count(es);
1799
1800         if (test_opt(sb, DEBUG))
1801                 ext4_msg(sb, KERN_DEBUG,
1802                          "extending last group from %llu to %llu blocks",
1803                          o_blocks_count, n_blocks_count);
1804
1805         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1806                 return 0;
1807
1808         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1809                 ext4_msg(sb, KERN_ERR,
1810                          "filesystem too large to resize to %llu blocks safely",
1811                          n_blocks_count);
1812                 return -EINVAL;
1813         }
1814
1815         if (n_blocks_count < o_blocks_count) {
1816                 ext4_warning(sb, "can't shrink FS - resize aborted");
1817                 return -EINVAL;
1818         }
1819
1820         /* Handle the remaining blocks in the last group only. */
1821         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1822
1823         if (last == 0) {
1824                 ext4_warning(sb, "need to use ext2online to resize further");
1825                 return -EPERM;
1826         }
1827
1828         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1829
1830         if (o_blocks_count + add < o_blocks_count) {
1831                 ext4_warning(sb, "blocks_count overflow");
1832                 return -EINVAL;
1833         }
1834
1835         if (o_blocks_count + add > n_blocks_count)
1836                 add = n_blocks_count - o_blocks_count;
1837
1838         if (o_blocks_count + add < n_blocks_count)
1839                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1840                              o_blocks_count + add, add);
1841
1842         /* See if the device is actually as big as what was requested */
1843         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1844         if (IS_ERR(bh)) {
1845                 ext4_warning(sb, "can't read last block, resize aborted");
1846                 return -ENOSPC;
1847         }
1848         brelse(bh);
1849
1850         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1851         return err;
1852 } /* ext4_group_extend */
1853
1854
1855 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1856 {
1857         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1858 }
1859
1860 /*
1861  * Release the resize inode and drop the resize_inode feature if there
1862  * are no more reserved gdt blocks, and then convert the file system
1863  * to enable meta_bg
1864  */
1865 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1866 {
1867         handle_t *handle;
1868         struct ext4_sb_info *sbi = EXT4_SB(sb);
1869         struct ext4_super_block *es = sbi->s_es;
1870         struct ext4_inode_info *ei = EXT4_I(inode);
1871         ext4_fsblk_t nr;
1872         int i, ret, err = 0;
1873         int credits = 1;
1874
1875         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1876         if (inode) {
1877                 if (es->s_reserved_gdt_blocks) {
1878                         ext4_error(sb, "Unexpected non-zero "
1879                                    "s_reserved_gdt_blocks");
1880                         return -EPERM;
1881                 }
1882
1883                 /* Do a quick sanity check of the resize inode */
1884                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1885                                              (9 - sbi->s_cluster_bits)))
1886                         goto invalid_resize_inode;
1887                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1888                         if (i == EXT4_DIND_BLOCK) {
1889                                 if (ei->i_data[i])
1890                                         continue;
1891                                 else
1892                                         goto invalid_resize_inode;
1893                         }
1894                         if (ei->i_data[i])
1895                                 goto invalid_resize_inode;
1896                 }
1897                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1898         }
1899
1900         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1901         if (IS_ERR(handle))
1902                 return PTR_ERR(handle);
1903
1904         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1905         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1906                                             EXT4_JTR_NONE);
1907         if (err)
1908                 goto errout;
1909
1910         lock_buffer(sbi->s_sbh);
1911         ext4_clear_feature_resize_inode(sb);
1912         ext4_set_feature_meta_bg(sb);
1913         sbi->s_es->s_first_meta_bg =
1914                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1915         ext4_superblock_csum_set(sb);
1916         unlock_buffer(sbi->s_sbh);
1917
1918         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1919         if (err) {
1920                 ext4_std_error(sb, err);
1921                 goto errout;
1922         }
1923
1924         if (inode) {
1925                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1926                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1927                                  EXT4_FREE_BLOCKS_METADATA |
1928                                  EXT4_FREE_BLOCKS_FORGET);
1929                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1930                 inode->i_blocks = 0;
1931
1932                 err = ext4_mark_inode_dirty(handle, inode);
1933                 if (err)
1934                         ext4_std_error(sb, err);
1935         }
1936
1937 errout:
1938         ret = ext4_journal_stop(handle);
1939         if (!err)
1940                 err = ret;
1941         return ret;
1942
1943 invalid_resize_inode:
1944         ext4_error(sb, "corrupted/inconsistent resize inode");
1945         return -EINVAL;
1946 }
1947
1948 /*
1949  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1950  *
1951  * @sb: super block of the fs to be resized
1952  * @n_blocks_count: the number of blocks resides in the resized fs
1953  */
1954 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1955 {
1956         struct ext4_new_flex_group_data *flex_gd = NULL;
1957         struct ext4_sb_info *sbi = EXT4_SB(sb);
1958         struct ext4_super_block *es = sbi->s_es;
1959         struct buffer_head *bh;
1960         struct inode *resize_inode = NULL;
1961         ext4_grpblk_t add, offset;
1962         unsigned long n_desc_blocks;
1963         unsigned long o_desc_blocks;
1964         ext4_group_t o_group;
1965         ext4_group_t n_group;
1966         ext4_fsblk_t o_blocks_count;
1967         ext4_fsblk_t n_blocks_count_retry = 0;
1968         unsigned long last_update_time = 0;
1969         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1970         int meta_bg;
1971
1972         /* See if the device is actually as big as what was requested */
1973         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
1974         if (IS_ERR(bh)) {
1975                 ext4_warning(sb, "can't read last block, resize aborted");
1976                 return -ENOSPC;
1977         }
1978         brelse(bh);
1979
1980         /*
1981          * For bigalloc, trim the requested size to the nearest cluster
1982          * boundary to avoid creating an unusable filesystem. We do this
1983          * silently, instead of returning an error, to avoid breaking
1984          * callers that blindly resize the filesystem to the full size of
1985          * the underlying block device.
1986          */
1987         if (ext4_has_feature_bigalloc(sb))
1988                 n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
1989
1990 retry:
1991         o_blocks_count = ext4_blocks_count(es);
1992
1993         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1994                  "to %llu blocks", o_blocks_count, n_blocks_count);
1995
1996         if (n_blocks_count < o_blocks_count) {
1997                 /* On-line shrinking not supported */
1998                 ext4_warning(sb, "can't shrink FS - resize aborted");
1999                 return -EINVAL;
2000         }
2001
2002         if (n_blocks_count == o_blocks_count)
2003                 /* Nothing need to do */
2004                 return 0;
2005
2006         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
2007         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2008                 ext4_warning(sb, "resize would cause inodes_count overflow");
2009                 return -EINVAL;
2010         }
2011         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2012
2013         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2014         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2015
2016         meta_bg = ext4_has_feature_meta_bg(sb);
2017
2018         if (ext4_has_feature_resize_inode(sb)) {
2019                 if (meta_bg) {
2020                         ext4_error(sb, "resize_inode and meta_bg enabled "
2021                                    "simultaneously");
2022                         return -EINVAL;
2023                 }
2024                 if (n_desc_blocks > o_desc_blocks +
2025                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
2026                         n_blocks_count_retry = n_blocks_count;
2027                         n_desc_blocks = o_desc_blocks +
2028                                 le16_to_cpu(es->s_reserved_gdt_blocks);
2029                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2030                         n_blocks_count = (ext4_fsblk_t)n_group *
2031                                 EXT4_BLOCKS_PER_GROUP(sb) +
2032                                 le32_to_cpu(es->s_first_data_block);
2033                         n_group--; /* set to last group number */
2034                 }
2035
2036                 if (!resize_inode)
2037                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2038                                                  EXT4_IGET_SPECIAL);
2039                 if (IS_ERR(resize_inode)) {
2040                         ext4_warning(sb, "Error opening resize inode");
2041                         return PTR_ERR(resize_inode);
2042                 }
2043         }
2044
2045         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2046                 err = ext4_convert_meta_bg(sb, resize_inode);
2047                 if (err)
2048                         goto out;
2049                 if (resize_inode) {
2050                         iput(resize_inode);
2051                         resize_inode = NULL;
2052                 }
2053                 if (n_blocks_count_retry) {
2054                         n_blocks_count = n_blocks_count_retry;
2055                         n_blocks_count_retry = 0;
2056                         goto retry;
2057                 }
2058         }
2059
2060         /*
2061          * Make sure the last group has enough space so that it's
2062          * guaranteed to have enough space for all metadata blocks
2063          * that it might need to hold.  (We might not need to store
2064          * the inode table blocks in the last block group, but there
2065          * will be cases where this might be needed.)
2066          */
2067         if ((ext4_group_first_block_no(sb, n_group) +
2068              ext4_group_overhead_blocks(sb, n_group) + 2 +
2069              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2070                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2071                 n_group--;
2072                 n_blocks_count_retry = 0;
2073                 if (resize_inode) {
2074                         iput(resize_inode);
2075                         resize_inode = NULL;
2076                 }
2077                 goto retry;
2078         }
2079
2080         /* extend the last group */
2081         if (n_group == o_group)
2082                 add = n_blocks_count - o_blocks_count;
2083         else
2084                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2085         if (add > 0) {
2086                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2087                 if (err)
2088                         goto out;
2089         }
2090
2091         if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2092                 goto out;
2093
2094         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2095         if (err)
2096                 goto out;
2097
2098         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2099         if (err)
2100                 goto out;
2101
2102         flex_gd = alloc_flex_gd(flexbg_size);
2103         if (flex_gd == NULL) {
2104                 err = -ENOMEM;
2105                 goto out;
2106         }
2107
2108         /* Add flex groups. Note that a regular group is a
2109          * flex group with 1 group.
2110          */
2111         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2112                                               flexbg_size)) {
2113                 if (jiffies - last_update_time > HZ * 10) {
2114                         if (last_update_time)
2115                                 ext4_msg(sb, KERN_INFO,
2116                                          "resized to %llu blocks",
2117                                          ext4_blocks_count(es));
2118                         last_update_time = jiffies;
2119                 }
2120                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2121                         break;
2122                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2123                 if (unlikely(err))
2124                         break;
2125         }
2126
2127         if (!err && n_blocks_count_retry) {
2128                 n_blocks_count = n_blocks_count_retry;
2129                 n_blocks_count_retry = 0;
2130                 free_flex_gd(flex_gd);
2131                 flex_gd = NULL;
2132                 if (resize_inode) {
2133                         iput(resize_inode);
2134                         resize_inode = NULL;
2135                 }
2136                 goto retry;
2137         }
2138
2139 out:
2140         if (flex_gd)
2141                 free_flex_gd(flex_gd);
2142         if (resize_inode != NULL)
2143                 iput(resize_inode);
2144         if (err)
2145                 ext4_warning(sb, "error (%d) occurred during "
2146                              "file system resize", err);
2147         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2148                  ext4_blocks_count(es));
2149         return err;
2150 }