fs/ext4/resize.c

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