fs/ext4/resize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/resize.c
   4  *
   5  * Support for resizing an ext4 filesystem while it is mounted.
   6  *
   7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17 #include <linux/jiffies.h>
  18
  19 #include "ext4_jbd2.h"
  20
  21 struct ext4_rcu_ptr {
  22         struct rcu_head rcu;
  23         void *ptr;
  24 };
  25
  26 static void ext4_rcu_ptr_callback(struct rcu_head *head)
  27 {
  28         struct ext4_rcu_ptr *ptr;
  29
  30         ptr = container_of(head, struct ext4_rcu_ptr, rcu);
  31         kvfree(ptr->ptr);
  32         kfree(ptr);
  33 }
  34
  35 void ext4_kvfree_array_rcu(void *to_free)
  36 {
  37         struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
  38
  39         if (ptr) {
  40                 ptr->ptr = to_free;
  41                 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
  42                 return;
  43         }
  44         synchronize_rcu();
  45         kvfree(to_free);
  46 }
  47
  48 int ext4_resize_begin(struct super_block *sb)
  49 {
  50         struct ext4_sb_info *sbi = EXT4_SB(sb);
  51         int ret = 0;
  52
  53         if (!capable(CAP_SYS_RESOURCE))
  54                 return -EPERM;
  55
  56         /*
  57          * If the reserved GDT blocks is non-zero, the resize_inode feature
  58          * should always be set.
  59          */
  60         if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
  61             !ext4_has_feature_resize_inode(sb)) {
  62                 ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
  63                 return -EFSCORRUPTED;
  64         }
  65
  66         /*
  67          * If we are not using the primary superblock/GDT copy don't resize,
  68          * because the user tools have no way of handling this.  Probably a
  69          * bad time to do it anyways.
  70          */
  71         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  72             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  73                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  74                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  75                 return -EPERM;
  76         }
  77
  78         /*
  79          * We are not allowed to do online-resizing on a filesystem mounted
  80          * with error, because it can destroy the filesystem easily.
  81          */
  82         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  83                 ext4_warning(sb, "There are errors in the filesystem, "
  84                              "so online resizing is not allowed");
  85                 return -EPERM;
  86         }
  87
  88         if (ext4_has_feature_sparse_super2(sb)) {
  89                 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
  90                 return -EOPNOTSUPP;
  91         }
  92
  93         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  94                                   &EXT4_SB(sb)->s_ext4_flags))
  95                 ret = -EBUSY;
  96
  97         return ret;
  98 }
  99
 100 int ext4_resize_end(struct super_block *sb, bool update_backups)
 101 {
 102         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
 103         smp_mb__after_atomic();
 104         if (update_backups)
 105                 return ext4_update_overhead(sb, true);
 106         return 0;
 107 }
 108
 109 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
 110                                              ext4_group_t group) {
 111         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
 112                EXT4_DESC_PER_BLOCK_BITS(sb);
 113 }
 114
 115 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
 116                                              ext4_group_t group) {
 117         group = ext4_meta_bg_first_group(sb, group);
 118         return ext4_group_first_block_no(sb, group);
 119 }
 120
 121 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 122                                                 ext4_group_t group) {
 123         ext4_grpblk_t overhead;
 124         overhead = ext4_bg_num_gdb(sb, group);
 125         if (ext4_bg_has_super(sb, group))
 126                 overhead += 1 +
 127                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 128         return overhead;
 129 }
 130
 131 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
 132 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
 133
 134 static int verify_group_input(struct super_block *sb,
 135                               struct ext4_new_group_data *input)
 136 {
 137         struct ext4_sb_info *sbi = EXT4_SB(sb);
 138         struct ext4_super_block *es = sbi->s_es;
 139         ext4_fsblk_t start = ext4_blocks_count(es);
 140         ext4_fsblk_t end = start + input->blocks_count;
 141         ext4_group_t group = input->group;
 142         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 143         unsigned overhead;
 144         ext4_fsblk_t metaend;
 145         struct buffer_head *bh = NULL;
 146         ext4_grpblk_t free_blocks_count, offset;
 147         int err = -EINVAL;
 148
 149         if (group != sbi->s_groups_count) {
 150                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 151                              input->group, sbi->s_groups_count);
 152                 return -EINVAL;
 153         }
 154
 155         overhead = ext4_group_overhead_blocks(sb, group);
 156         metaend = start + overhead;
 157         input->free_clusters_count = free_blocks_count =
 158                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 159
 160         if (test_opt(sb, DEBUG))
 161                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 162                        "(%d free, %u reserved)\n",
 163                        ext4_bg_has_super(sb, input->group) ? "normal" :
 164                        "no-super", input->group, input->blocks_count,
 165                        free_blocks_count, input->reserved_blocks);
 166
 167         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 168         if (offset != 0)
 169                         ext4_warning(sb, "Last group not full");
 170         else if (input->reserved_blocks > input->blocks_count / 5)
 171                 ext4_warning(sb, "Reserved blocks too high (%u)",
 172                              input->reserved_blocks);
 173         else if (free_blocks_count < 0)
 174                 ext4_warning(sb, "Bad blocks count %u",
 175                              input->blocks_count);
 176         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 177                 err = PTR_ERR(bh);
 178                 bh = NULL;
 179                 ext4_warning(sb, "Cannot read last block (%llu)",
 180                              end - 1);
 181         } else if (outside(input->block_bitmap, start, end))
 182                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 183                              (unsigned long long)input->block_bitmap);
 184         else if (outside(input->inode_bitmap, start, end))
 185                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 186                              (unsigned long long)input->inode_bitmap);
 187         else if (outside(input->inode_table, start, end) ||
 188                  outside(itend - 1, start, end))
 189                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 190                              (unsigned long long)input->inode_table, itend - 1);
 191         else if (input->inode_bitmap == input->block_bitmap)
 192                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 193                              (unsigned long long)input->block_bitmap);
 194         else if (inside(input->block_bitmap, input->inode_table, itend))
 195                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 196                              "(%llu-%llu)",
 197                              (unsigned long long)input->block_bitmap,
 198                              (unsigned long long)input->inode_table, itend - 1);
 199         else if (inside(input->inode_bitmap, input->inode_table, itend))
 200                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 201                              "(%llu-%llu)",
 202                              (unsigned long long)input->inode_bitmap,
 203                              (unsigned long long)input->inode_table, itend - 1);
 204         else if (inside(input->block_bitmap, start, metaend))
 205                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 206                              (unsigned long long)input->block_bitmap,
 207                              start, metaend - 1);
 208         else if (inside(input->inode_bitmap, start, metaend))
 209                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 210                              (unsigned long long)input->inode_bitmap,
 211                              start, metaend - 1);
 212         else if (inside(input->inode_table, start, metaend) ||
 213                  inside(itend - 1, start, metaend))
 214                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 215                              "(%llu-%llu)",
 216                              (unsigned long long)input->inode_table,
 217                              itend - 1, start, metaend - 1);
 218         else
 219                 err = 0;
 220         brelse(bh);
 221
 222         return err;
 223 }
 224
 225 /*
 226  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 227  * group each time.
 228  */
 229 struct ext4_new_flex_group_data {
 230         struct ext4_new_group_data *groups;     /* new_group_data for groups
 231                                                    in the flex group */
 232         __u16 *bg_flags;                        /* block group flags of groups
 233                                                    in @groups */
 234         ext4_group_t count;                     /* number of groups in @groups
 235                                                  */
 236 };
 237
 238 /*
 239  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 240  * @flexbg_size.
 241  *
 242  * Returns NULL on failure otherwise address of the allocated structure.
 243  */
 244 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 245 {
 246         struct ext4_new_flex_group_data *flex_gd;
 247
 248         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 249         if (flex_gd == NULL)
 250                 goto out3;
 251
 252         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 253                 goto out2;
 254         flex_gd->count = flexbg_size;
 255
 256         flex_gd->groups = kmalloc_array(flexbg_size,
 257                                         sizeof(struct ext4_new_group_data),
 258                                         GFP_NOFS);
 259         if (flex_gd->groups == NULL)
 260                 goto out2;
 261
 262         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 263                                           GFP_NOFS);
 264         if (flex_gd->bg_flags == NULL)
 265                 goto out1;
 266
 267         return flex_gd;
 268
 269 out1:
 270         kfree(flex_gd->groups);
 271 out2:
 272         kfree(flex_gd);
 273 out3:
 274         return NULL;
 275 }
 276
 277 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 278 {
 279         kfree(flex_gd->bg_flags);
 280         kfree(flex_gd->groups);
 281         kfree(flex_gd);
 282 }
 283
 284 /*
 285  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 286  * and inode tables for a flex group.
 287  *
 288  * This function is used by 64bit-resize.  Note that this function allocates
 289  * group tables from the 1st group of groups contained by @flexgd, which may
 290  * be a partial of a flex group.
 291  *
 292  * @sb: super block of fs to which the groups belongs
 293  *
 294  * Returns 0 on a successful allocation of the metadata blocks in the
 295  * block group.
 296  */
 297 static int ext4_alloc_group_tables(struct super_block *sb,
 298                                 struct ext4_new_flex_group_data *flex_gd,
 299                                 int flexbg_size)
 300 {
 301         struct ext4_new_group_data *group_data = flex_gd->groups;
 302         ext4_fsblk_t start_blk;
 303         ext4_fsblk_t last_blk;
 304         ext4_group_t src_group;
 305         ext4_group_t bb_index = 0;
 306         ext4_group_t ib_index = 0;
 307         ext4_group_t it_index = 0;
 308         ext4_group_t group;
 309         ext4_group_t last_group;
 310         unsigned overhead;
 311         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 312         int i;
 313
 314         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 315
 316         src_group = group_data[0].group;
 317         last_group  = src_group + flex_gd->count - 1;
 318
 319         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 320                (last_group & ~(flexbg_size - 1))));
 321 next_group:
 322         group = group_data[0].group;
 323         if (src_group >= group_data[0].group + flex_gd->count)
 324                 return -ENOSPC;
 325         start_blk = ext4_group_first_block_no(sb, src_group);
 326         last_blk = start_blk + group_data[src_group - group].blocks_count;
 327
 328         overhead = ext4_group_overhead_blocks(sb, src_group);
 329
 330         start_blk += overhead;
 331
 332         /* We collect contiguous blocks as much as possible. */
 333         src_group++;
 334         for (; src_group <= last_group; src_group++) {
 335                 overhead = ext4_group_overhead_blocks(sb, src_group);
 336                 if (overhead == 0)
 337                         last_blk += group_data[src_group - group].blocks_count;
 338                 else
 339                         break;
 340         }
 341
 342         /* Allocate block bitmaps */
 343         for (; bb_index < flex_gd->count; bb_index++) {
 344                 if (start_blk >= last_blk)
 345                         goto next_group;
 346                 group_data[bb_index].block_bitmap = start_blk++;
 347                 group = ext4_get_group_number(sb, start_blk - 1);
 348                 group -= group_data[0].group;
 349                 group_data[group].mdata_blocks++;
 350                 flex_gd->bg_flags[group] &= uninit_mask;
 351         }
 352
 353         /* Allocate inode bitmaps */
 354         for (; ib_index < flex_gd->count; ib_index++) {
 355                 if (start_blk >= last_blk)
 356                         goto next_group;
 357                 group_data[ib_index].inode_bitmap = start_blk++;
 358                 group = ext4_get_group_number(sb, start_blk - 1);
 359                 group -= group_data[0].group;
 360                 group_data[group].mdata_blocks++;
 361                 flex_gd->bg_flags[group] &= uninit_mask;
 362         }
 363
 364         /* Allocate inode tables */
 365         for (; it_index < flex_gd->count; it_index++) {
 366                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 367                 ext4_fsblk_t next_group_start;
 368
 369                 if (start_blk + itb > last_blk)
 370                         goto next_group;
 371                 group_data[it_index].inode_table = start_blk;
 372                 group = ext4_get_group_number(sb, start_blk);
 373                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 374                 group -= group_data[0].group;
 375
 376                 if (start_blk + itb > next_group_start) {
 377                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 378                         overhead = start_blk + itb - next_group_start;
 379                         group_data[group + 1].mdata_blocks += overhead;
 380                         itb -= overhead;
 381                 }
 382
 383                 group_data[group].mdata_blocks += itb;
 384                 flex_gd->bg_flags[group] &= uninit_mask;
 385                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 386         }
 387
 388         /* Update free clusters count to exclude metadata blocks */
 389         for (i = 0; i < flex_gd->count; i++) {
 390                 group_data[i].free_clusters_count -=
 391                                 EXT4_NUM_B2C(EXT4_SB(sb),
 392                                              group_data[i].mdata_blocks);
 393         }
 394
 395         if (test_opt(sb, DEBUG)) {
 396                 int i;
 397                 group = group_data[0].group;
 398
 399                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 400                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 401                        flexbg_size);
 402
 403                 for (i = 0; i < flex_gd->count; i++) {
 404                         ext4_debug(
 405                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 406                                ext4_bg_has_super(sb, group + i) ? "normal" :
 407                                "no-super", group + i,
 408                                group_data[i].blocks_count,
 409                                group_data[i].free_clusters_count,
 410                                group_data[i].mdata_blocks);
 411                 }
 412         }
 413         return 0;
 414 }
 415
 416 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 417                                   ext4_fsblk_t blk)
 418 {
 419         struct buffer_head *bh;
 420         int err;
 421
 422         bh = sb_getblk(sb, blk);
 423         if (unlikely(!bh))
 424                 return ERR_PTR(-ENOMEM);
 425         BUFFER_TRACE(bh, "get_write_access");
 426         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
 427         if (err) {
 428                 brelse(bh);
 429                 bh = ERR_PTR(err);
 430         } else {
 431                 memset(bh->b_data, 0, sb->s_blocksize);
 432                 set_buffer_uptodate(bh);
 433         }
 434
 435         return bh;
 436 }
 437
 438 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 439 {
 440         return ext4_journal_ensure_credits_fn(handle, credits,
 441                 EXT4_MAX_TRANS_DATA, 0, 0);
 442 }
 443
 444 /*
 445  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 446  *
 447  * Helper function for ext4_setup_new_group_blocks() which set .
 448  *
 449  * @sb: super block
 450  * @handle: journal handle
 451  * @flex_gd: flex group data
 452  */
 453 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 454                         struct ext4_new_flex_group_data *flex_gd,
 455                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 456 {
 457         struct ext4_sb_info *sbi = EXT4_SB(sb);
 458         ext4_group_t count = last_cluster - first_cluster + 1;
 459         ext4_group_t count2;
 460
 461         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 462                    last_cluster);
 463         for (count2 = count; count > 0;
 464              count -= count2, first_cluster += count2) {
 465                 ext4_fsblk_t start;
 466                 struct buffer_head *bh;
 467                 ext4_group_t group;
 468                 int err;
 469
 470                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 471                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 472                 group -= flex_gd->groups[0].group;
 473
 474                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 475                 if (count2 > count)
 476                         count2 = count;
 477
 478                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 479                         BUG_ON(flex_gd->count > 1);
 480                         continue;
 481                 }
 482
 483                 err = ext4_resize_ensure_credits_batch(handle, 1);
 484                 if (err < 0)
 485                         return err;
 486
 487                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 488                 if (unlikely(!bh))
 489                         return -ENOMEM;
 490
 491                 BUFFER_TRACE(bh, "get_write_access");
 492                 err = ext4_journal_get_write_access(handle, sb, bh,
 493                                                     EXT4_JTR_NONE);
 494                 if (err) {
 495                         brelse(bh);
 496                         return err;
 497                 }
 498                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 499                            first_cluster, first_cluster - start, count2);
 500                 mb_set_bits(bh->b_data, first_cluster - start, count2);
 501
 502                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 503                 brelse(bh);
 504                 if (unlikely(err))
 505                         return err;
 506         }
 507
 508         return 0;
 509 }
 510
 511 /*
 512  * Set up the block and inode bitmaps, and the inode table for the new groups.
 513  * This doesn't need to be part of the main transaction, since we are only
 514  * changing blocks outside the actual filesystem.  We still do journaling to
 515  * ensure the recovery is correct in case of a failure just after resize.
 516  * If any part of this fails, we simply abort the resize.
 517  *
 518  * setup_new_flex_group_blocks handles a flex group as follow:
 519  *  1. copy super block and GDT, and initialize group tables if necessary.
 520  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 521  *     super block and GDT.
 522  *  2. allocate group tables in block bitmaps, that is, set bits in block
 523  *     bitmap for blocks taken by group tables.
 524  */
 525 static int setup_new_flex_group_blocks(struct super_block *sb,
 526                                 struct ext4_new_flex_group_data *flex_gd)
 527 {
 528         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 529         ext4_fsblk_t start;
 530         ext4_fsblk_t block;
 531         struct ext4_sb_info *sbi = EXT4_SB(sb);
 532         struct ext4_super_block *es = sbi->s_es;
 533         struct ext4_new_group_data *group_data = flex_gd->groups;
 534         __u16 *bg_flags = flex_gd->bg_flags;
 535         handle_t *handle;
 536         ext4_group_t group, count;
 537         struct buffer_head *bh = NULL;
 538         int reserved_gdb, i, j, err = 0, err2;
 539         int meta_bg;
 540
 541         BUG_ON(!flex_gd->count || !group_data ||
 542                group_data[0].group != sbi->s_groups_count);
 543
 544         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 545         meta_bg = ext4_has_feature_meta_bg(sb);
 546
 547         /* This transaction may be extended/restarted along the way */
 548         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 549         if (IS_ERR(handle))
 550                 return PTR_ERR(handle);
 551
 552         group = group_data[0].group;
 553         for (i = 0; i < flex_gd->count; i++, group++) {
 554                 unsigned long gdblocks;
 555                 ext4_grpblk_t overhead;
 556
 557                 gdblocks = ext4_bg_num_gdb(sb, group);
 558                 start = ext4_group_first_block_no(sb, group);
 559
 560                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 561                         goto handle_itb;
 562
 563                 if (meta_bg == 1) {
 564                         ext4_group_t first_group;
 565                         first_group = ext4_meta_bg_first_group(sb, group);
 566                         if (first_group != group + 1 &&
 567                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 568                                 goto handle_itb;
 569                 }
 570
 571                 block = start + ext4_bg_has_super(sb, group);
 572                 /* Copy all of the GDT blocks into the backup in this group */
 573                 for (j = 0; j < gdblocks; j++, block++) {
 574                         struct buffer_head *gdb;
 575
 576                         ext4_debug("update backup group %#04llx\n", block);
 577                         err = ext4_resize_ensure_credits_batch(handle, 1);
 578                         if (err < 0)
 579                                 goto out;
 580
 581                         gdb = sb_getblk(sb, block);
 582                         if (unlikely(!gdb)) {
 583                                 err = -ENOMEM;
 584                                 goto out;
 585                         }
 586
 587                         BUFFER_TRACE(gdb, "get_write_access");
 588                         err = ext4_journal_get_write_access(handle, sb, gdb,
 589                                                             EXT4_JTR_NONE);
 590                         if (err) {
 591                                 brelse(gdb);
 592                                 goto out;
 593                         }
 594                         memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
 595                                 s_group_desc, j)->b_data, gdb->b_size);
 596                         set_buffer_uptodate(gdb);
 597
 598                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 599                         if (unlikely(err)) {
 600                                 brelse(gdb);
 601                                 goto out;
 602                         }
 603                         brelse(gdb);
 604                 }
 605
 606                 /* Zero out all of the reserved backup group descriptor
 607                  * table blocks
 608                  */
 609                 if (ext4_bg_has_super(sb, group)) {
 610                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 611                                         reserved_gdb, GFP_NOFS);
 612                         if (err)
 613                                 goto out;
 614                 }
 615
 616 handle_itb:
 617                 /* Initialize group tables of the grop @group */
 618                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 619                         goto handle_bb;
 620
 621                 /* Zero out all of the inode table blocks */
 622                 block = group_data[i].inode_table;
 623                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 624                            block, sbi->s_itb_per_group);
 625                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 626                                        GFP_NOFS);
 627                 if (err)
 628                         goto out;
 629
 630 handle_bb:
 631                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 632                         goto handle_ib;
 633
 634                 /* Initialize block bitmap of the @group */
 635                 block = group_data[i].block_bitmap;
 636                 err = ext4_resize_ensure_credits_batch(handle, 1);
 637                 if (err < 0)
 638                         goto out;
 639
 640                 bh = bclean(handle, sb, block);
 641                 if (IS_ERR(bh)) {
 642                         err = PTR_ERR(bh);
 643                         goto out;
 644                 }
 645                 overhead = ext4_group_overhead_blocks(sb, group);
 646                 if (overhead != 0) {
 647                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 648                                    start);
 649                         mb_set_bits(bh->b_data, 0,
 650                                       EXT4_NUM_B2C(sbi, overhead));
 651                 }
 652                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 653                                      sb->s_blocksize * 8, bh->b_data);
 654                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 655                 brelse(bh);
 656                 if (err)
 657                         goto out;
 658
 659 handle_ib:
 660                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 661                         continue;
 662
 663                 /* Initialize inode bitmap of the @group */
 664                 block = group_data[i].inode_bitmap;
 665                 err = ext4_resize_ensure_credits_batch(handle, 1);
 666                 if (err < 0)
 667                         goto out;
 668                 /* Mark unused entries in inode bitmap used */
 669                 bh = bclean(handle, sb, block);
 670                 if (IS_ERR(bh)) {
 671                         err = PTR_ERR(bh);
 672                         goto out;
 673                 }
 674
 675                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 676                                      sb->s_blocksize * 8, bh->b_data);
 677                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 678                 brelse(bh);
 679                 if (err)
 680                         goto out;
 681         }
 682
 683         /* Mark group tables in block bitmap */
 684         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 685                 count = group_table_count[j];
 686                 start = (&group_data[0].block_bitmap)[j];
 687                 block = start;
 688                 for (i = 1; i < flex_gd->count; i++) {
 689                         block += group_table_count[j];
 690                         if (block == (&group_data[i].block_bitmap)[j]) {
 691                                 count += group_table_count[j];
 692                                 continue;
 693                         }
 694                         err = set_flexbg_block_bitmap(sb, handle,
 695                                                       flex_gd,
 696                                                       EXT4_B2C(sbi, start),
 697                                                       EXT4_B2C(sbi,
 698                                                                start + count
 699                                                                - 1));
 700                         if (err)
 701                                 goto out;
 702                         count = group_table_count[j];
 703                         start = (&group_data[i].block_bitmap)[j];
 704                         block = start;
 705                 }
 706
 707                 if (count) {
 708                         err = set_flexbg_block_bitmap(sb, handle,
 709                                                       flex_gd,
 710                                                       EXT4_B2C(sbi, start),
 711                                                       EXT4_B2C(sbi,
 712                                                                start + count
 713                                                                - 1));
 714                         if (err)
 715                                 goto out;
 716                 }
 717         }
 718
 719 out:
 720         err2 = ext4_journal_stop(handle);
 721         if (err2 && !err)
 722                 err = err2;
 723
 724         return err;
 725 }
 726
 727 /*
 728  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 729  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 730  * calling this for the first time.  In a sparse filesystem it will be the
 731  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 732  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 733  */
 734 unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three,
 735                                unsigned int *five, unsigned int *seven)
 736 {
 737         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 738         unsigned int *min = three;
 739         int mult = 3;
 740         unsigned int ret;
 741
 742         if (ext4_has_feature_sparse_super2(sb)) {
 743                 do {
 744                         if (*min > 2)
 745                                 return UINT_MAX;
 746                         ret = le32_to_cpu(es->s_backup_bgs[*min - 1]);
 747                         *min += 1;
 748                 } while (!ret);
 749                 return ret;
 750         }
 751
 752         if (!ext4_has_feature_sparse_super(sb)) {
 753                 ret = *min;
 754                 *min += 1;
 755                 return ret;
 756         }
 757
 758         if (*five < *min) {
 759                 min = five;
 760                 mult = 5;
 761         }
 762         if (*seven < *min) {
 763                 min = seven;
 764                 mult = 7;
 765         }
 766
 767         ret = *min;
 768         *min *= mult;
 769
 770         return ret;
 771 }
 772
 773 /*
 774  * Check that all of the backup GDT blocks are held in the primary GDT block.
 775  * It is assumed that they are stored in group order.  Returns the number of
 776  * groups in current filesystem that have BACKUPS, or -ve error code.
 777  */
 778 static int verify_reserved_gdb(struct super_block *sb,
 779                                ext4_group_t end,
 780                                struct buffer_head *primary)
 781 {
 782         const ext4_fsblk_t blk = primary->b_blocknr;
 783         unsigned three = 1;
 784         unsigned five = 5;
 785         unsigned seven = 7;
 786         unsigned grp;
 787         __le32 *p = (__le32 *)primary->b_data;
 788         int gdbackups = 0;
 789
 790         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 791                 if (le32_to_cpu(*p++) !=
 792                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 793                         ext4_warning(sb, "reserved GDT %llu"
 794                                      " missing grp %d (%llu)",
 795                                      blk, grp,
 796                                      grp *
 797                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 798                                      blk);
 799                         return -EINVAL;
 800                 }
 801                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 802                         return -EFBIG;
 803         }
 804
 805         return gdbackups;
 806 }
 807
 808 /*
 809  * Called when we need to bring a reserved group descriptor table block into
 810  * use from the resize inode.  The primary copy of the new GDT block currently
 811  * is an indirect block (under the double indirect block in the resize inode).
 812  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 813  * block, in group order.  Even though we know all the block numbers we need,
 814  * we check to ensure that the resize inode has actually reserved these blocks.
 815  *
 816  * Don't need to update the block bitmaps because the blocks are still in use.
 817  *
 818  * We get all of the error cases out of the way, so that we are sure to not
 819  * fail once we start modifying the data on disk, because JBD has no rollback.
 820  */
 821 static int add_new_gdb(handle_t *handle, struct inode *inode,
 822                        ext4_group_t group)
 823 {
 824         struct super_block *sb = inode->i_sb;
 825         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 826         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 827         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 828         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 829         struct buffer_head *dind = NULL;
 830         struct buffer_head *gdb_bh = NULL;
 831         int gdbackups;
 832         struct ext4_iloc iloc = { .bh = NULL };
 833         __le32 *data;
 834         int err;
 835
 836         if (test_opt(sb, DEBUG))
 837                 printk(KERN_DEBUG
 838                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 839                        gdb_num);
 840
 841         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 842         if (IS_ERR(gdb_bh))
 843                 return PTR_ERR(gdb_bh);
 844
 845         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 846         if (gdbackups < 0) {
 847                 err = gdbackups;
 848                 goto errout;
 849         }
 850
 851         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 852         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 853         if (IS_ERR(dind)) {
 854                 err = PTR_ERR(dind);
 855                 dind = NULL;
 856                 goto errout;
 857         }
 858
 859         data = (__le32 *)dind->b_data;
 860         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 861                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 862                              group, gdblock);
 863                 err = -EINVAL;
 864                 goto errout;
 865         }
 866
 867         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 868         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 869                                             EXT4_JTR_NONE);
 870         if (unlikely(err))
 871                 goto errout;
 872
 873         BUFFER_TRACE(gdb_bh, "get_write_access");
 874         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 875         if (unlikely(err))
 876                 goto errout;
 877
 878         BUFFER_TRACE(dind, "get_write_access");
 879         err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
 880         if (unlikely(err)) {
 881                 ext4_std_error(sb, err);
 882                 goto errout;
 883         }
 884
 885         /* ext4_reserve_inode_write() gets a reference on the iloc */
 886         err = ext4_reserve_inode_write(handle, inode, &iloc);
 887         if (unlikely(err))
 888                 goto errout;
 889
 890         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 891                                 GFP_KERNEL);
 892         if (!n_group_desc) {
 893                 err = -ENOMEM;
 894                 ext4_warning(sb, "not enough memory for %lu groups",
 895                              gdb_num + 1);
 896                 goto errout;
 897         }
 898
 899         /*
 900          * Finally, we have all of the possible failures behind us...
 901          *
 902          * Remove new GDT block from inode double-indirect block and clear out
 903          * the new GDT block for use (which also "frees" the backup GDT blocks
 904          * from the reserved inode).  We don't need to change the bitmaps for
 905          * these blocks, because they are marked as in-use from being in the
 906          * reserved inode, and will become GDT blocks (primary and backup).
 907          */
 908         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 909         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 910         if (unlikely(err)) {
 911                 ext4_std_error(sb, err);
 912                 goto errout;
 913         }
 914         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 915                            (9 - EXT4_SB(sb)->s_cluster_bits);
 916         ext4_mark_iloc_dirty(handle, inode, &iloc);
 917         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 918         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 919         if (unlikely(err)) {
 920                 ext4_std_error(sb, err);
 921                 iloc.bh = NULL;
 922                 goto errout;
 923         }
 924         brelse(dind);
 925
 926         rcu_read_lock();
 927         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 928         memcpy(n_group_desc, o_group_desc,
 929                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 930         rcu_read_unlock();
 931         n_group_desc[gdb_num] = gdb_bh;
 932         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 933         EXT4_SB(sb)->s_gdb_count++;
 934         ext4_kvfree_array_rcu(o_group_desc);
 935
 936         lock_buffer(EXT4_SB(sb)->s_sbh);
 937         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 938         ext4_superblock_csum_set(sb);
 939         unlock_buffer(EXT4_SB(sb)->s_sbh);
 940         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 941         if (err)
 942                 ext4_std_error(sb, err);
 943         return err;
 944 errout:
 945         kvfree(n_group_desc);
 946         brelse(iloc.bh);
 947         brelse(dind);
 948         brelse(gdb_bh);
 949
 950         ext4_debug("leaving with error %d\n", err);
 951         return err;
 952 }
 953
 954 /*
 955  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 956  */
 957 static int add_new_gdb_meta_bg(struct super_block *sb,
 958                                handle_t *handle, ext4_group_t group) {
 959         ext4_fsblk_t gdblock;
 960         struct buffer_head *gdb_bh;
 961         struct buffer_head **o_group_desc, **n_group_desc;
 962         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 963         int err;
 964
 965         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 966                    ext4_bg_has_super(sb, group);
 967         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 968         if (IS_ERR(gdb_bh))
 969                 return PTR_ERR(gdb_bh);
 970         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 971                                 GFP_KERNEL);
 972         if (!n_group_desc) {
 973                 brelse(gdb_bh);
 974                 err = -ENOMEM;
 975                 ext4_warning(sb, "not enough memory for %lu groups",
 976                              gdb_num + 1);
 977                 return err;
 978         }
 979
 980         rcu_read_lock();
 981         o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
 982         memcpy(n_group_desc, o_group_desc,
 983                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 984         rcu_read_unlock();
 985         n_group_desc[gdb_num] = gdb_bh;
 986
 987         BUFFER_TRACE(gdb_bh, "get_write_access");
 988         err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
 989         if (err) {
 990                 kvfree(n_group_desc);
 991                 brelse(gdb_bh);
 992                 return err;
 993         }
 994
 995         rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
 996         EXT4_SB(sb)->s_gdb_count++;
 997         ext4_kvfree_array_rcu(o_group_desc);
 998         return err;
 999 }
1000
1001 /*
1002  * Called when we are adding a new group which has a backup copy of each of
1003  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
1004  * We need to add these reserved backup GDT blocks to the resize inode, so
1005  * that they are kept for future resizing and not allocated to files.
1006  *
1007  * Each reserved backup GDT block will go into a different indirect block.
1008  * The indirect blocks are actually the primary reserved GDT blocks,
1009  * so we know in advance what their block numbers are.  We only get the
1010  * double-indirect block to verify it is pointing to the primary reserved
1011  * GDT blocks so we don't overwrite a data block by accident.  The reserved
1012  * backup GDT blocks are stored in their reserved primary GDT block.
1013  */
1014 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1015                               ext4_group_t group)
1016 {
1017         struct super_block *sb = inode->i_sb;
1018         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1019         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1020         struct buffer_head **primary;
1021         struct buffer_head *dind;
1022         struct ext4_iloc iloc;
1023         ext4_fsblk_t blk;
1024         __le32 *data, *end;
1025         int gdbackups = 0;
1026         int res, i;
1027         int err;
1028
1029         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1030         if (!primary)
1031                 return -ENOMEM;
1032
1033         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1034         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1035         if (IS_ERR(dind)) {
1036                 err = PTR_ERR(dind);
1037                 dind = NULL;
1038                 goto exit_free;
1039         }
1040
1041         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1042         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1043                                          EXT4_ADDR_PER_BLOCK(sb));
1044         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1045
1046         /* Get each reserved primary GDT block and verify it holds backups */
1047         for (res = 0; res < reserved_gdb; res++, blk++) {
1048                 if (le32_to_cpu(*data) != blk) {
1049                         ext4_warning(sb, "reserved block %llu"
1050                                      " not at offset %ld",
1051                                      blk,
1052                                      (long)(data - (__le32 *)dind->b_data));
1053                         err = -EINVAL;
1054                         goto exit_bh;
1055                 }
1056                 primary[res] = ext4_sb_bread(sb, blk, 0);
1057                 if (IS_ERR(primary[res])) {
1058                         err = PTR_ERR(primary[res]);
1059                         primary[res] = NULL;
1060                         goto exit_bh;
1061                 }
1062                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1063                 if (gdbackups < 0) {
1064                         brelse(primary[res]);
1065                         err = gdbackups;
1066                         goto exit_bh;
1067                 }
1068                 if (++data >= end)
1069                         data = (__le32 *)dind->b_data;
1070         }
1071
1072         for (i = 0; i < reserved_gdb; i++) {
1073                 BUFFER_TRACE(primary[i], "get_write_access");
1074                 if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1075                                                          EXT4_JTR_NONE)))
1076                         goto exit_bh;
1077         }
1078
1079         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1080                 goto exit_bh;
1081
1082         /*
1083          * Finally we can add each of the reserved backup GDT blocks from
1084          * the new group to its reserved primary GDT block.
1085          */
1086         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1087         for (i = 0; i < reserved_gdb; i++) {
1088                 int err2;
1089                 data = (__le32 *)primary[i]->b_data;
1090                 /* printk("reserving backup %lu[%u] = %lu\n",
1091                        primary[i]->b_blocknr, gdbackups,
1092                        blk + primary[i]->b_blocknr); */
1093                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1094                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1095                 if (!err)
1096                         err = err2;
1097         }
1098
1099         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1100         ext4_mark_iloc_dirty(handle, inode, &iloc);
1101
1102 exit_bh:
1103         while (--res >= 0)
1104                 brelse(primary[res]);
1105         brelse(dind);
1106
1107 exit_free:
1108         kfree(primary);
1109
1110         return err;
1111 }
1112
1113 static inline void ext4_set_block_group_nr(struct super_block *sb, char *data,
1114                                            ext4_group_t group)
1115 {
1116         struct ext4_super_block *es = (struct ext4_super_block *) data;
1117
1118         es->s_block_group_nr = cpu_to_le16(group);
1119         if (ext4_has_metadata_csum(sb))
1120                 es->s_checksum = ext4_superblock_csum(sb, es);
1121 }
1122
1123 /*
1124  * Update the backup copies of the ext4 metadata.  These don't need to be part
1125  * of the main resize transaction, because e2fsck will re-write them if there
1126  * is a problem (basically only OOM will cause a problem).  However, we
1127  * _should_ update the backups if possible, in case the primary gets trashed
1128  * for some reason and we need to run e2fsck from a backup superblock.  The
1129  * important part is that the new block and inode counts are in the backup
1130  * superblocks, and the location of the new group metadata in the GDT backups.
1131  *
1132  * We do not need take the s_resize_lock for this, because these
1133  * blocks are not otherwise touched by the filesystem code when it is
1134  * mounted.  We don't need to worry about last changing from
1135  * sbi->s_groups_count, because the worst that can happen is that we
1136  * do not copy the full number of backups at this time.  The resize
1137  * which changed s_groups_count will backup again.
1138  */
1139 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1140                            int size, int meta_bg)
1141 {
1142         struct ext4_sb_info *sbi = EXT4_SB(sb);
1143         ext4_group_t last;
1144         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1145         unsigned three = 1;
1146         unsigned five = 5;
1147         unsigned seven = 7;
1148         ext4_group_t group = 0;
1149         int rest = sb->s_blocksize - size;
1150         handle_t *handle;
1151         int err = 0, err2;
1152
1153         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1154         if (IS_ERR(handle)) {
1155                 group = 1;
1156                 err = PTR_ERR(handle);
1157                 goto exit_err;
1158         }
1159
1160         if (meta_bg == 0) {
1161                 group = ext4_list_backups(sb, &three, &five, &seven);
1162                 last = sbi->s_groups_count;
1163         } else {
1164                 group = ext4_get_group_number(sb, blk_off) + 1;
1165                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1166         }
1167
1168         while (group < sbi->s_groups_count) {
1169                 struct buffer_head *bh;
1170                 ext4_fsblk_t backup_block;
1171                 int has_super = ext4_bg_has_super(sb, group);
1172                 ext4_fsblk_t first_block = ext4_group_first_block_no(sb, group);
1173
1174                 /* Out of journal space, and can't get more - abort - so sad */
1175                 err = ext4_resize_ensure_credits_batch(handle, 1);
1176                 if (err < 0)
1177                         break;
1178
1179                 if (meta_bg == 0)
1180                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1181                 else
1182                         backup_block = first_block + has_super;
1183
1184                 bh = sb_getblk(sb, backup_block);
1185                 if (unlikely(!bh)) {
1186                         err = -ENOMEM;
1187                         break;
1188                 }
1189                 ext4_debug("update metadata backup %llu(+%llu)\n",
1190                            backup_block, backup_block -
1191                            ext4_group_first_block_no(sb, group));
1192                 BUFFER_TRACE(bh, "get_write_access");
1193                 if ((err = ext4_journal_get_write_access(handle, sb, bh,
1194                                                          EXT4_JTR_NONE)))
1195                         break;
1196                 lock_buffer(bh);
1197                 memcpy(bh->b_data, data, size);
1198                 if (rest)
1199                         memset(bh->b_data + size, 0, rest);
1200                 if (has_super && (backup_block == first_block))
1201                         ext4_set_block_group_nr(sb, bh->b_data, group);
1202                 set_buffer_uptodate(bh);
1203                 unlock_buffer(bh);
1204                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1205                 if (unlikely(err))
1206                         ext4_std_error(sb, err);
1207                 brelse(bh);
1208
1209                 if (meta_bg == 0)
1210                         group = ext4_list_backups(sb, &three, &five, &seven);
1211                 else if (group == last)
1212                         break;
1213                 else
1214                         group = last;
1215         }
1216         if ((err2 = ext4_journal_stop(handle)) && !err)
1217                 err = err2;
1218
1219         /*
1220          * Ugh! Need to have e2fsck write the backup copies.  It is too
1221          * late to revert the resize, we shouldn't fail just because of
1222          * the backup copies (they are only needed in case of corruption).
1223          *
1224          * However, if we got here we have a journal problem too, so we
1225          * can't really start a transaction to mark the superblock.
1226          * Chicken out and just set the flag on the hope it will be written
1227          * to disk, and if not - we will simply wait until next fsck.
1228          */
1229 exit_err:
1230         if (err) {
1231                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1232                              "forcing fsck on next reboot", group, err);
1233                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1234                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1235                 mark_buffer_dirty(sbi->s_sbh);
1236         }
1237 }
1238
1239 /*
1240  * ext4_add_new_descs() adds @count group descriptor of groups
1241  * starting at @group
1242  *
1243  * @handle: journal handle
1244  * @sb: super block
1245  * @group: the group no. of the first group desc to be added
1246  * @resize_inode: the resize inode
1247  * @count: number of group descriptors to be added
1248  */
1249 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1250                               ext4_group_t group, struct inode *resize_inode,
1251                               ext4_group_t count)
1252 {
1253         struct ext4_sb_info *sbi = EXT4_SB(sb);
1254         struct ext4_super_block *es = sbi->s_es;
1255         struct buffer_head *gdb_bh;
1256         int i, gdb_off, gdb_num, err = 0;
1257         int meta_bg;
1258
1259         meta_bg = ext4_has_feature_meta_bg(sb);
1260         for (i = 0; i < count; i++, group++) {
1261                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1262                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1263
1264                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1265                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1266
1267                 /*
1268                  * We will only either add reserved group blocks to a backup group
1269                  * or remove reserved blocks for the first group in a new group block.
1270                  * Doing both would be mean more complex code, and sane people don't
1271                  * use non-sparse filesystems anymore.  This is already checked above.
1272                  */
1273                 if (gdb_off) {
1274                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1275                                                      gdb_num);
1276                         BUFFER_TRACE(gdb_bh, "get_write_access");
1277                         err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1278                                                             EXT4_JTR_NONE);
1279
1280                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1281                                 err = reserve_backup_gdb(handle, resize_inode, group);
1282                 } else if (meta_bg != 0) {
1283                         err = add_new_gdb_meta_bg(sb, handle, group);
1284                 } else {
1285                         err = add_new_gdb(handle, resize_inode, group);
1286                 }
1287                 if (err)
1288                         break;
1289         }
1290         return err;
1291 }
1292
1293 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1294 {
1295         struct buffer_head *bh = sb_getblk(sb, block);
1296         if (unlikely(!bh))
1297                 return NULL;
1298         if (!bh_uptodate_or_lock(bh)) {
1299                 if (ext4_read_bh(bh, 0, NULL) < 0) {
1300                         brelse(bh);
1301                         return NULL;
1302                 }
1303         }
1304
1305         return bh;
1306 }
1307
1308 static int ext4_set_bitmap_checksums(struct super_block *sb,
1309                                      struct ext4_group_desc *gdp,
1310                                      struct ext4_new_group_data *group_data)
1311 {
1312         struct buffer_head *bh;
1313
1314         if (!ext4_has_metadata_csum(sb))
1315                 return 0;
1316
1317         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1318         if (!bh)
1319                 return -EIO;
1320         ext4_inode_bitmap_csum_set(sb, gdp, bh,
1321                                    EXT4_INODES_PER_GROUP(sb) / 8);
1322         brelse(bh);
1323
1324         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1325         if (!bh)
1326                 return -EIO;
1327         ext4_block_bitmap_csum_set(sb, gdp, bh);
1328         brelse(bh);
1329
1330         return 0;
1331 }
1332
1333 /*
1334  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1335  */
1336 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1337                                 struct ext4_new_flex_group_data *flex_gd)
1338 {
1339         struct ext4_new_group_data      *group_data = flex_gd->groups;
1340         struct ext4_group_desc          *gdp;
1341         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1342         struct buffer_head              *gdb_bh;
1343         ext4_group_t                    group;
1344         __u16                           *bg_flags = flex_gd->bg_flags;
1345         int                             i, gdb_off, gdb_num, err = 0;
1346
1347
1348         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1349                 group = group_data->group;
1350
1351                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1352                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1353
1354                 /*
1355                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1356                  */
1357                 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1358                 /* Update group descriptor block for new group */
1359                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1360                                                  gdb_off * EXT4_DESC_SIZE(sb));
1361
1362                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1363                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1364                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1365                 err = ext4_set_bitmap_checksums(sb, gdp, group_data);
1366                 if (err) {
1367                         ext4_std_error(sb, err);
1368                         break;
1369                 }
1370
1371                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1372                 ext4_free_group_clusters_set(sb, gdp,
1373                                              group_data->free_clusters_count);
1374                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1375                 if (ext4_has_group_desc_csum(sb))
1376                         ext4_itable_unused_set(sb, gdp,
1377                                                EXT4_INODES_PER_GROUP(sb));
1378                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1379                 ext4_group_desc_csum_set(sb, group, gdp);
1380
1381                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1382                 if (unlikely(err)) {
1383                         ext4_std_error(sb, err);
1384                         break;
1385                 }
1386
1387                 /*
1388                  * We can allocate memory for mb_alloc based on the new group
1389                  * descriptor
1390                  */
1391                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1392                 if (err)
1393                         break;
1394         }
1395         return err;
1396 }
1397
1398 static void ext4_add_overhead(struct super_block *sb,
1399                               const ext4_fsblk_t overhead)
1400 {
1401        struct ext4_sb_info *sbi = EXT4_SB(sb);
1402        struct ext4_super_block *es = sbi->s_es;
1403
1404        sbi->s_overhead += overhead;
1405        es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1406        smp_wmb();
1407 }
1408
1409 /*
1410  * ext4_update_super() updates the super block so that the newly added
1411  * groups can be seen by the filesystem.
1412  *
1413  * @sb: super block
1414  * @flex_gd: new added groups
1415  */
1416 static void ext4_update_super(struct super_block *sb,
1417                              struct ext4_new_flex_group_data *flex_gd)
1418 {
1419         ext4_fsblk_t blocks_count = 0;
1420         ext4_fsblk_t free_blocks = 0;
1421         ext4_fsblk_t reserved_blocks = 0;
1422         struct ext4_new_group_data *group_data = flex_gd->groups;
1423         struct ext4_sb_info *sbi = EXT4_SB(sb);
1424         struct ext4_super_block *es = sbi->s_es;
1425         int i;
1426
1427         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1428         /*
1429          * Make the new blocks and inodes valid next.  We do this before
1430          * increasing the group count so that once the group is enabled,
1431          * all of its blocks and inodes are already valid.
1432          *
1433          * We always allocate group-by-group, then block-by-block or
1434          * inode-by-inode within a group, so enabling these
1435          * blocks/inodes before the group is live won't actually let us
1436          * allocate the new space yet.
1437          */
1438         for (i = 0; i < flex_gd->count; i++) {
1439                 blocks_count += group_data[i].blocks_count;
1440                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1441         }
1442
1443         reserved_blocks = ext4_r_blocks_count(es) * 100;
1444         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1445         reserved_blocks *= blocks_count;
1446         do_div(reserved_blocks, 100);
1447
1448         lock_buffer(sbi->s_sbh);
1449         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1450         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1451         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1452                      flex_gd->count);
1453         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1454                      flex_gd->count);
1455
1456         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1457         /*
1458          * We need to protect s_groups_count against other CPUs seeing
1459          * inconsistent state in the superblock.
1460          *
1461          * The precise rules we use are:
1462          *
1463          * * Writers must perform a smp_wmb() after updating all
1464          *   dependent data and before modifying the groups count
1465          *
1466          * * Readers must perform an smp_rmb() after reading the groups
1467          *   count and before reading any dependent data.
1468          *
1469          * NB. These rules can be relaxed when checking the group count
1470          * while freeing data, as we can only allocate from a block
1471          * group after serialising against the group count, and we can
1472          * only then free after serialising in turn against that
1473          * allocation.
1474          */
1475         smp_wmb();
1476
1477         /* Update the global fs size fields */
1478         sbi->s_groups_count += flex_gd->count;
1479         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1480                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1481
1482         /* Update the reserved block counts only once the new group is
1483          * active. */
1484         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1485                                 reserved_blocks);
1486
1487         /* Update the free space counts */
1488         percpu_counter_add(&sbi->s_freeclusters_counter,
1489                            EXT4_NUM_B2C(sbi, free_blocks));
1490         percpu_counter_add(&sbi->s_freeinodes_counter,
1491                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1492
1493         ext4_debug("free blocks count %llu",
1494                    percpu_counter_read(&sbi->s_freeclusters_counter));
1495         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1496                 ext4_group_t flex_group;
1497                 struct flex_groups *fg;
1498
1499                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1500                 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1501                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1502                              &fg->free_clusters);
1503                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1504                            &fg->free_inodes);
1505         }
1506
1507         /*
1508          * Update the fs overhead information.
1509          *
1510          * For bigalloc, if the superblock already has a properly calculated
1511          * overhead, update it with a value based on numbers already computed
1512          * above for the newly allocated capacity.
1513          */
1514         if (ext4_has_feature_bigalloc(sb) && (sbi->s_overhead != 0))
1515                 ext4_add_overhead(sb,
1516                         EXT4_NUM_B2C(sbi, blocks_count - free_blocks));
1517         else
1518                 ext4_calculate_overhead(sb);
1519         es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1520
1521         ext4_superblock_csum_set(sb);
1522         unlock_buffer(sbi->s_sbh);
1523         if (test_opt(sb, DEBUG))
1524                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1525                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1526                        blocks_count, free_blocks, reserved_blocks);
1527 }
1528
1529 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1530  * _before_ we start modifying the filesystem, because we cannot abort the
1531  * transaction and not have it write the data to disk.
1532  */
1533 static int ext4_flex_group_add(struct super_block *sb,
1534                                struct inode *resize_inode,
1535                                struct ext4_new_flex_group_data *flex_gd)
1536 {
1537         struct ext4_sb_info *sbi = EXT4_SB(sb);
1538         struct ext4_super_block *es = sbi->s_es;
1539         ext4_fsblk_t o_blocks_count;
1540         ext4_grpblk_t last;
1541         ext4_group_t group;
1542         handle_t *handle;
1543         unsigned reserved_gdb;
1544         int err = 0, err2 = 0, credit;
1545
1546         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1547
1548         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1549         o_blocks_count = ext4_blocks_count(es);
1550         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1551         BUG_ON(last);
1552
1553         err = setup_new_flex_group_blocks(sb, flex_gd);
1554         if (err)
1555                 goto exit;
1556         /*
1557          * We will always be modifying at least the superblock and  GDT
1558          * blocks.  If we are adding a group past the last current GDT block,
1559          * we will also modify the inode and the dindirect block.  If we
1560          * are adding a group with superblock/GDT backups  we will also
1561          * modify each of the reserved GDT dindirect blocks.
1562          */
1563         credit = 3;     /* sb, resize inode, resize inode dindirect */
1564         /* GDT blocks */
1565         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1566         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1567         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1568         if (IS_ERR(handle)) {
1569                 err = PTR_ERR(handle);
1570                 goto exit;
1571         }
1572
1573         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1574         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1575                                             EXT4_JTR_NONE);
1576         if (err)
1577                 goto exit_journal;
1578
1579         group = flex_gd->groups[0].group;
1580         BUG_ON(group != sbi->s_groups_count);
1581         err = ext4_add_new_descs(handle, sb, group,
1582                                 resize_inode, flex_gd->count);
1583         if (err)
1584                 goto exit_journal;
1585
1586         err = ext4_setup_new_descs(handle, sb, flex_gd);
1587         if (err)
1588                 goto exit_journal;
1589
1590         ext4_update_super(sb, flex_gd);
1591
1592         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1593
1594 exit_journal:
1595         err2 = ext4_journal_stop(handle);
1596         if (!err)
1597                 err = err2;
1598
1599         if (!err) {
1600                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1601                 int gdb_num_end = ((group + flex_gd->count - 1) /
1602                                    EXT4_DESC_PER_BLOCK(sb));
1603                 int meta_bg = ext4_has_feature_meta_bg(sb);
1604                 sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
1605                                          ext4_group_first_block_no(sb, 0);
1606                 sector_t old_gdb = 0;
1607
1608                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1609                                (char *)es, sizeof(struct ext4_super_block), 0);
1610                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1611                         struct buffer_head *gdb_bh;
1612
1613                         gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1614                                                      gdb_num);
1615                         if (old_gdb == gdb_bh->b_blocknr)
1616                                 continue;
1617                         update_backups(sb, gdb_bh->b_blocknr - padding_blocks,
1618                                        gdb_bh->b_data, gdb_bh->b_size, meta_bg);
1619                         old_gdb = gdb_bh->b_blocknr;
1620                 }
1621         }
1622 exit:
1623         return err;
1624 }
1625
1626 static int ext4_setup_next_flex_gd(struct super_block *sb,
1627                                     struct ext4_new_flex_group_data *flex_gd,
1628                                     ext4_fsblk_t n_blocks_count,
1629                                     unsigned long flexbg_size)
1630 {
1631         struct ext4_sb_info *sbi = EXT4_SB(sb);
1632         struct ext4_super_block *es = sbi->s_es;
1633         struct ext4_new_group_data *group_data = flex_gd->groups;
1634         ext4_fsblk_t o_blocks_count;
1635         ext4_group_t n_group;
1636         ext4_group_t group;
1637         ext4_group_t last_group;
1638         ext4_grpblk_t last;
1639         ext4_grpblk_t clusters_per_group;
1640         unsigned long i;
1641
1642         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1643
1644         o_blocks_count = ext4_blocks_count(es);
1645
1646         if (o_blocks_count == n_blocks_count)
1647                 return 0;
1648
1649         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1650         BUG_ON(last);
1651         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1652
1653         last_group = group | (flexbg_size - 1);
1654         if (last_group > n_group)
1655                 last_group = n_group;
1656
1657         flex_gd->count = last_group - group + 1;
1658
1659         for (i = 0; i < flex_gd->count; i++) {
1660                 int overhead;
1661
1662                 group_data[i].group = group + i;
1663                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1664                 overhead = ext4_group_overhead_blocks(sb, group + i);
1665                 group_data[i].mdata_blocks = overhead;
1666                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1667                 if (ext4_has_group_desc_csum(sb)) {
1668                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1669                                                EXT4_BG_INODE_UNINIT;
1670                         if (!test_opt(sb, INIT_INODE_TABLE))
1671                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1672                 } else
1673                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1674         }
1675
1676         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1677                 /* We need to initialize block bitmap of last group. */
1678                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1679
1680         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1681                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1682                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1683                                                        last - 1;
1684         }
1685
1686         return 1;
1687 }
1688
1689 /* Add group descriptor data to an existing or new group descriptor block.
1690  * Ensure we handle all possible error conditions _before_ we start modifying
1691  * the filesystem, because we cannot abort the transaction and not have it
1692  * write the data to disk.
1693  *
1694  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1695  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1696  *
1697  * We only need to hold the superblock lock while we are actually adding
1698  * in the new group's counts to the superblock.  Prior to that we have
1699  * not really "added" the group at all.  We re-check that we are still
1700  * adding in the last group in case things have changed since verifying.
1701  */
1702 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1703 {
1704         struct ext4_new_flex_group_data flex_gd;
1705         struct ext4_sb_info *sbi = EXT4_SB(sb);
1706         struct ext4_super_block *es = sbi->s_es;
1707         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1708                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1709         struct inode *inode = NULL;
1710         int gdb_off;
1711         int err;
1712         __u16 bg_flags = 0;
1713
1714         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1715
1716         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1717                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1718                 return -EPERM;
1719         }
1720
1721         if (ext4_blocks_count(es) + input->blocks_count <
1722             ext4_blocks_count(es)) {
1723                 ext4_warning(sb, "blocks_count overflow");
1724                 return -EINVAL;
1725         }
1726
1727         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1728             le32_to_cpu(es->s_inodes_count)) {
1729                 ext4_warning(sb, "inodes_count overflow");
1730                 return -EINVAL;
1731         }
1732
1733         if (reserved_gdb || gdb_off == 0) {
1734                 if (!ext4_has_feature_resize_inode(sb) ||
1735                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1736                         ext4_warning(sb,
1737                                      "No reserved GDT blocks, can't resize");
1738                         return -EPERM;
1739                 }
1740                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1741                 if (IS_ERR(inode)) {
1742                         ext4_warning(sb, "Error opening resize inode");
1743                         return PTR_ERR(inode);
1744                 }
1745         }
1746
1747
1748         err = verify_group_input(sb, input);
1749         if (err)
1750                 goto out;
1751
1752         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1753         if (err)
1754                 goto out;
1755
1756         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1757         if (err)
1758                 goto out;
1759
1760         flex_gd.count = 1;
1761         flex_gd.groups = input;
1762         flex_gd.bg_flags = &bg_flags;
1763         err = ext4_flex_group_add(sb, inode, &flex_gd);
1764 out:
1765         iput(inode);
1766         return err;
1767 } /* ext4_group_add */
1768
1769 /*
1770  * extend a group without checking assuming that checking has been done.
1771  */
1772 static int ext4_group_extend_no_check(struct super_block *sb,
1773                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1774 {
1775         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1776         handle_t *handle;
1777         int err = 0, err2;
1778
1779         /* We will update the superblock, one block bitmap, and
1780          * one group descriptor via ext4_group_add_blocks().
1781          */
1782         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1783         if (IS_ERR(handle)) {
1784                 err = PTR_ERR(handle);
1785                 ext4_warning(sb, "error %d on journal start", err);
1786                 return err;
1787         }
1788
1789         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1790         err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1791                                             EXT4_JTR_NONE);
1792         if (err) {
1793                 ext4_warning(sb, "error %d on journal write access", err);
1794                 goto errout;
1795         }
1796
1797         lock_buffer(EXT4_SB(sb)->s_sbh);
1798         ext4_blocks_count_set(es, o_blocks_count + add);
1799         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1800         ext4_superblock_csum_set(sb);
1801         unlock_buffer(EXT4_SB(sb)->s_sbh);
1802         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1803                    o_blocks_count + add);
1804         /* We add the blocks to the bitmap and set the group need init bit */
1805         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1806         if (err)
1807                 goto errout;
1808         ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1809         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1810                    o_blocks_count + add);
1811 errout:
1812         err2 = ext4_journal_stop(handle);
1813         if (err2 && !err)
1814                 err = err2;
1815
1816         if (!err) {
1817                 if (test_opt(sb, DEBUG))
1818                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1819                                "blocks\n", ext4_blocks_count(es));
1820                 update_backups(sb, ext4_group_first_block_no(sb, 0),
1821                                (char *)es, sizeof(struct ext4_super_block), 0);
1822         }
1823         return err;
1824 }
1825
1826 /*
1827  * Extend the filesystem to the new number of blocks specified.  This entry
1828  * point is only used to extend the current filesystem to the end of the last
1829  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1830  * for emergencies (because it has no dependencies on reserved blocks).
1831  *
1832  * If we _really_ wanted, we could use default values to call ext4_group_add()
1833  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1834  * GDT blocks are reserved to grow to the desired size.
1835  */
1836 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1837                       ext4_fsblk_t n_blocks_count)
1838 {
1839         ext4_fsblk_t o_blocks_count;
1840         ext4_grpblk_t last;
1841         ext4_grpblk_t add;
1842         struct buffer_head *bh;
1843         ext4_group_t group;
1844
1845         o_blocks_count = ext4_blocks_count(es);
1846
1847         if (test_opt(sb, DEBUG))
1848                 ext4_msg(sb, KERN_DEBUG,
1849                          "extending last group from %llu to %llu blocks",
1850                          o_blocks_count, n_blocks_count);
1851
1852         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1853                 return 0;
1854
1855         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1856                 ext4_msg(sb, KERN_ERR,
1857                          "filesystem too large to resize to %llu blocks safely",
1858                          n_blocks_count);
1859                 return -EINVAL;
1860         }
1861
1862         if (n_blocks_count < o_blocks_count) {
1863                 ext4_warning(sb, "can't shrink FS - resize aborted");
1864                 return -EINVAL;
1865         }
1866
1867         /* Handle the remaining blocks in the last group only. */
1868         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1869
1870         if (last == 0) {
1871                 ext4_warning(sb, "need to use ext2online to resize further");
1872                 return -EPERM;
1873         }
1874
1875         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1876
1877         if (o_blocks_count + add < o_blocks_count) {
1878                 ext4_warning(sb, "blocks_count overflow");
1879                 return -EINVAL;
1880         }
1881
1882         if (o_blocks_count + add > n_blocks_count)
1883                 add = n_blocks_count - o_blocks_count;
1884
1885         if (o_blocks_count + add < n_blocks_count)
1886                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1887                              o_blocks_count + add, add);
1888
1889         /* See if the device is actually as big as what was requested */
1890         bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1891         if (IS_ERR(bh)) {
1892                 ext4_warning(sb, "can't read last block, resize aborted");
1893                 return -ENOSPC;
1894         }
1895         brelse(bh);
1896
1897         return ext4_group_extend_no_check(sb, o_blocks_count, add);
1898 } /* ext4_group_extend */
1899
1900
1901 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1902 {
1903         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1904 }
1905
1906 /*
1907  * Release the resize inode and drop the resize_inode feature if there
1908  * are no more reserved gdt blocks, and then convert the file system
1909  * to enable meta_bg
1910  */
1911 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1912 {
1913         handle_t *handle;
1914         struct ext4_sb_info *sbi = EXT4_SB(sb);
1915         struct ext4_super_block *es = sbi->s_es;
1916         struct ext4_inode_info *ei = EXT4_I(inode);
1917         ext4_fsblk_t nr;
1918         int i, ret, err = 0;
1919         int credits = 1;
1920
1921         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1922         if (inode) {
1923                 if (es->s_reserved_gdt_blocks) {
1924                         ext4_error(sb, "Unexpected non-zero "
1925                                    "s_reserved_gdt_blocks");
1926                         return -EPERM;
1927                 }
1928
1929                 /* Do a quick sanity check of the resize inode */
1930                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1931                                              (9 - sbi->s_cluster_bits)))
1932                         goto invalid_resize_inode;
1933                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1934                         if (i == EXT4_DIND_BLOCK) {
1935                                 if (ei->i_data[i])
1936                                         continue;
1937                                 else
1938                                         goto invalid_resize_inode;
1939                         }
1940                         if (ei->i_data[i])
1941                                 goto invalid_resize_inode;
1942                 }
1943                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1944         }
1945
1946         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1947         if (IS_ERR(handle))
1948                 return PTR_ERR(handle);
1949
1950         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1951         err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1952                                             EXT4_JTR_NONE);
1953         if (err)
1954                 goto errout;
1955
1956         lock_buffer(sbi->s_sbh);
1957         ext4_clear_feature_resize_inode(sb);
1958         ext4_set_feature_meta_bg(sb);
1959         sbi->s_es->s_first_meta_bg =
1960                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1961         ext4_superblock_csum_set(sb);
1962         unlock_buffer(sbi->s_sbh);
1963
1964         err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1965         if (err) {
1966                 ext4_std_error(sb, err);
1967                 goto errout;
1968         }
1969
1970         if (inode) {
1971                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1972                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1973                                  EXT4_FREE_BLOCKS_METADATA |
1974                                  EXT4_FREE_BLOCKS_FORGET);
1975                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1976                 inode->i_blocks = 0;
1977
1978                 err = ext4_mark_inode_dirty(handle, inode);
1979                 if (err)
1980                         ext4_std_error(sb, err);
1981         }
1982
1983 errout:
1984         ret = ext4_journal_stop(handle);
1985         return err ? err : ret;
1986
1987 invalid_resize_inode:
1988         ext4_error(sb, "corrupted/inconsistent resize inode");
1989         return -EINVAL;
1990 }
1991
1992 /*
1993  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1994  *
1995  * @sb: super block of the fs to be resized
1996  * @n_blocks_count: the number of blocks resides in the resized fs
1997  */
1998 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1999 {
2000         struct ext4_new_flex_group_data *flex_gd = NULL;
2001         struct ext4_sb_info *sbi = EXT4_SB(sb);
2002         struct ext4_super_block *es = sbi->s_es;
2003         struct buffer_head *bh;
2004         struct inode *resize_inode = NULL;
2005         ext4_grpblk_t add, offset;
2006         unsigned long n_desc_blocks;
2007         unsigned long o_desc_blocks;
2008         ext4_group_t o_group;
2009         ext4_group_t n_group;
2010         ext4_fsblk_t o_blocks_count;
2011         ext4_fsblk_t n_blocks_count_retry = 0;
2012         unsigned long last_update_time = 0;
2013         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
2014         int meta_bg;
2015
2016         /* See if the device is actually as big as what was requested */
2017         bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
2018         if (IS_ERR(bh)) {
2019                 ext4_warning(sb, "can't read last block, resize aborted");
2020                 return -ENOSPC;
2021         }
2022         brelse(bh);
2023
2024         /*
2025          * For bigalloc, trim the requested size to the nearest cluster
2026          * boundary to avoid creating an unusable filesystem. We do this
2027          * silently, instead of returning an error, to avoid breaking
2028          * callers that blindly resize the filesystem to the full size of
2029          * the underlying block device.
2030          */
2031         if (ext4_has_feature_bigalloc(sb))
2032                 n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
2033
2034 retry:
2035         o_blocks_count = ext4_blocks_count(es);
2036
2037         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
2038                  "to %llu blocks", o_blocks_count, n_blocks_count);
2039
2040         if (n_blocks_count < o_blocks_count) {
2041                 /* On-line shrinking not supported */
2042                 ext4_warning(sb, "can't shrink FS - resize aborted");
2043                 return -EINVAL;
2044         }
2045
2046         if (n_blocks_count == o_blocks_count)
2047                 /* Nothing need to do */
2048                 return 0;
2049
2050         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
2051         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2052                 ext4_warning(sb, "resize would cause inodes_count overflow");
2053                 return -EINVAL;
2054         }
2055         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2056
2057         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2058         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2059
2060         meta_bg = ext4_has_feature_meta_bg(sb);
2061
2062         if (ext4_has_feature_resize_inode(sb)) {
2063                 if (meta_bg) {
2064                         ext4_error(sb, "resize_inode and meta_bg enabled "
2065                                    "simultaneously");
2066                         return -EINVAL;
2067                 }
2068                 if (n_desc_blocks > o_desc_blocks +
2069                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
2070                         n_blocks_count_retry = n_blocks_count;
2071                         n_desc_blocks = o_desc_blocks +
2072                                 le16_to_cpu(es->s_reserved_gdt_blocks);
2073                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2074                         n_blocks_count = (ext4_fsblk_t)n_group *
2075                                 EXT4_BLOCKS_PER_GROUP(sb) +
2076                                 le32_to_cpu(es->s_first_data_block);
2077                         n_group--; /* set to last group number */
2078                 }
2079
2080                 if (!resize_inode)
2081                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2082                                                  EXT4_IGET_SPECIAL);
2083                 if (IS_ERR(resize_inode)) {
2084                         ext4_warning(sb, "Error opening resize inode");
2085                         return PTR_ERR(resize_inode);
2086                 }
2087         }
2088
2089         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2090                 err = ext4_convert_meta_bg(sb, resize_inode);
2091                 if (err)
2092                         goto out;
2093                 if (resize_inode) {
2094                         iput(resize_inode);
2095                         resize_inode = NULL;
2096                 }
2097                 if (n_blocks_count_retry) {
2098                         n_blocks_count = n_blocks_count_retry;
2099                         n_blocks_count_retry = 0;
2100                         goto retry;
2101                 }
2102         }
2103
2104         /*
2105          * Make sure the last group has enough space so that it's
2106          * guaranteed to have enough space for all metadata blocks
2107          * that it might need to hold.  (We might not need to store
2108          * the inode table blocks in the last block group, but there
2109          * will be cases where this might be needed.)
2110          */
2111         if ((ext4_group_first_block_no(sb, n_group) +
2112              ext4_group_overhead_blocks(sb, n_group) + 2 +
2113              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2114                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2115                 n_group--;
2116                 n_blocks_count_retry = 0;
2117                 if (resize_inode) {
2118                         iput(resize_inode);
2119                         resize_inode = NULL;
2120                 }
2121                 goto retry;
2122         }
2123
2124         /* extend the last group */
2125         if (n_group == o_group)
2126                 add = n_blocks_count - o_blocks_count;
2127         else
2128                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2129         if (add > 0) {
2130                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2131                 if (err)
2132                         goto out;
2133         }
2134
2135         if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2136                 goto out;
2137
2138         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2139         if (err)
2140                 goto out;
2141
2142         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2143         if (err)
2144                 goto out;
2145
2146         flex_gd = alloc_flex_gd(flexbg_size);
2147         if (flex_gd == NULL) {
2148                 err = -ENOMEM;
2149                 goto out;
2150         }
2151
2152         /* Add flex groups. Note that a regular group is a
2153          * flex group with 1 group.
2154          */
2155         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2156                                               flexbg_size)) {
2157                 if (time_is_before_jiffies(last_update_time + HZ * 10)) {
2158                         if (last_update_time)
2159                                 ext4_msg(sb, KERN_INFO,
2160                                          "resized to %llu blocks",
2161                                          ext4_blocks_count(es));
2162                         last_update_time = jiffies;
2163                 }
2164                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2165                         break;
2166                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2167                 if (unlikely(err))
2168                         break;
2169         }
2170
2171         if (!err && n_blocks_count_retry) {
2172                 n_blocks_count = n_blocks_count_retry;
2173                 n_blocks_count_retry = 0;
2174                 free_flex_gd(flex_gd);
2175                 flex_gd = NULL;
2176                 if (resize_inode) {
2177                         iput(resize_inode);
2178                         resize_inode = NULL;
2179                 }
2180                 goto retry;
2181         }
2182
2183 out:
2184         if (flex_gd)
2185                 free_flex_gd(flex_gd);
2186         if (resize_inode != NULL)
2187                 iput(resize_inode);
2188         if (err)
2189                 ext4_warning(sb, "error (%d) occurred during "
2190                              "file system resize", err);
2191         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2192                  ext4_blocks_count(es));
2193         return err;
2194 }