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