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 <[email protected]>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17
  18 #include "ext4_jbd2.h"
  19
  20 int ext4_resize_begin(struct super_block *sb)
  21 {
  22         struct ext4_sb_info *sbi = EXT4_SB(sb);
  23         int ret = 0;
  24
  25         if (!capable(CAP_SYS_RESOURCE))
  26                 return -EPERM;
  27
  28         /*
  29          * If we are not using the primary superblock/GDT copy don't resize,
  30          * because the user tools have no way of handling this.  Probably a
  31          * bad time to do it anyways.
  32          */
  33         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  34             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  35                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  36                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  37                 return -EPERM;
  38         }
  39
  40         /*
  41          * We are not allowed to do online-resizing on a filesystem mounted
  42          * with error, because it can destroy the filesystem easily.
  43          */
  44         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  45                 ext4_warning(sb, "There are errors in the filesystem, "
  46                              "so online resizing is not allowed");
  47                 return -EPERM;
  48         }
  49
  50         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  51                                   &EXT4_SB(sb)->s_ext4_flags))
  52                 ret = -EBUSY;
  53
  54         return ret;
  55 }
  56
  57 void ext4_resize_end(struct super_block *sb)
  58 {
  59         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
  60         smp_mb__after_atomic();
  61 }
  62
  63 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  64                                              ext4_group_t group) {
  65         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  66                EXT4_DESC_PER_BLOCK_BITS(sb);
  67 }
  68
  69 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  70                                              ext4_group_t group) {
  71         group = ext4_meta_bg_first_group(sb, group);
  72         return ext4_group_first_block_no(sb, group);
  73 }
  74
  75 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  76                                                 ext4_group_t group) {
  77         ext4_grpblk_t overhead;
  78         overhead = ext4_bg_num_gdb(sb, group);
  79         if (ext4_bg_has_super(sb, group))
  80                 overhead += 1 +
  81                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  82         return overhead;
  83 }
  84
  85 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
  86 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  87
  88 static int verify_group_input(struct super_block *sb,
  89                               struct ext4_new_group_data *input)
  90 {
  91         struct ext4_sb_info *sbi = EXT4_SB(sb);
  92         struct ext4_super_block *es = sbi->s_es;
  93         ext4_fsblk_t start = ext4_blocks_count(es);
  94         ext4_fsblk_t end = start + input->blocks_count;
  95         ext4_group_t group = input->group;
  96         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  97         unsigned overhead;
  98         ext4_fsblk_t metaend;
  99         struct buffer_head *bh = NULL;
 100         ext4_grpblk_t free_blocks_count, offset;
 101         int err = -EINVAL;
 102
 103         if (group != sbi->s_groups_count) {
 104                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 105                              input->group, sbi->s_groups_count);
 106                 return -EINVAL;
 107         }
 108
 109         overhead = ext4_group_overhead_blocks(sb, group);
 110         metaend = start + overhead;
 111         input->free_clusters_count = free_blocks_count =
 112                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 113
 114         if (test_opt(sb, DEBUG))
 115                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 116                        "(%d free, %u reserved)\n",
 117                        ext4_bg_has_super(sb, input->group) ? "normal" :
 118                        "no-super", input->group, input->blocks_count,
 119                        free_blocks_count, input->reserved_blocks);
 120
 121         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 122         if (offset != 0)
 123                         ext4_warning(sb, "Last group not full");
 124         else if (input->reserved_blocks > input->blocks_count / 5)
 125                 ext4_warning(sb, "Reserved blocks too high (%u)",
 126                              input->reserved_blocks);
 127         else if (free_blocks_count < 0)
 128                 ext4_warning(sb, "Bad blocks count %u",
 129                              input->blocks_count);
 130         else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
 131                 err = PTR_ERR(bh);
 132                 bh = NULL;
 133                 ext4_warning(sb, "Cannot read last block (%llu)",
 134                              end - 1);
 135         } else if (outside(input->block_bitmap, start, end))
 136                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 137                              (unsigned long long)input->block_bitmap);
 138         else if (outside(input->inode_bitmap, start, end))
 139                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 140                              (unsigned long long)input->inode_bitmap);
 141         else if (outside(input->inode_table, start, end) ||
 142                  outside(itend - 1, start, end))
 143                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 144                              (unsigned long long)input->inode_table, itend - 1);
 145         else if (input->inode_bitmap == input->block_bitmap)
 146                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 147                              (unsigned long long)input->block_bitmap);
 148         else if (inside(input->block_bitmap, input->inode_table, itend))
 149                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 150                              "(%llu-%llu)",
 151                              (unsigned long long)input->block_bitmap,
 152                              (unsigned long long)input->inode_table, itend - 1);
 153         else if (inside(input->inode_bitmap, input->inode_table, itend))
 154                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 155                              "(%llu-%llu)",
 156                              (unsigned long long)input->inode_bitmap,
 157                              (unsigned long long)input->inode_table, itend - 1);
 158         else if (inside(input->block_bitmap, start, metaend))
 159                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 160                              (unsigned long long)input->block_bitmap,
 161                              start, metaend - 1);
 162         else if (inside(input->inode_bitmap, start, metaend))
 163                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 164                              (unsigned long long)input->inode_bitmap,
 165                              start, metaend - 1);
 166         else if (inside(input->inode_table, start, metaend) ||
 167                  inside(itend - 1, start, metaend))
 168                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 169                              "(%llu-%llu)",
 170                              (unsigned long long)input->inode_table,
 171                              itend - 1, start, metaend - 1);
 172         else
 173                 err = 0;
 174         brelse(bh);
 175
 176         return err;
 177 }
 178
 179 /*
 180  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 181  * group each time.
 182  */
 183 struct ext4_new_flex_group_data {
 184         struct ext4_new_group_data *groups;     /* new_group_data for groups
 185                                                    in the flex group */
 186         __u16 *bg_flags;                        /* block group flags of groups
 187                                                    in @groups */
 188         ext4_group_t count;                     /* number of groups in @groups
 189                                                  */
 190 };
 191
 192 /*
 193  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 194  * @flexbg_size.
 195  *
 196  * Returns NULL on failure otherwise address of the allocated structure.
 197  */
 198 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 199 {
 200         struct ext4_new_flex_group_data *flex_gd;
 201
 202         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 203         if (flex_gd == NULL)
 204                 goto out3;
 205
 206         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 207                 goto out2;
 208         flex_gd->count = flexbg_size;
 209
 210         flex_gd->groups = kmalloc_array(flexbg_size,
 211                                         sizeof(struct ext4_new_group_data),
 212                                         GFP_NOFS);
 213         if (flex_gd->groups == NULL)
 214                 goto out2;
 215
 216         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 217                                           GFP_NOFS);
 218         if (flex_gd->bg_flags == NULL)
 219                 goto out1;
 220
 221         return flex_gd;
 222
 223 out1:
 224         kfree(flex_gd->groups);
 225 out2:
 226         kfree(flex_gd);
 227 out3:
 228         return NULL;
 229 }
 230
 231 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 232 {
 233         kfree(flex_gd->bg_flags);
 234         kfree(flex_gd->groups);
 235         kfree(flex_gd);
 236 }
 237
 238 /*
 239  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 240  * and inode tables for a flex group.
 241  *
 242  * This function is used by 64bit-resize.  Note that this function allocates
 243  * group tables from the 1st group of groups contained by @flexgd, which may
 244  * be a partial of a flex group.
 245  *
 246  * @sb: super block of fs to which the groups belongs
 247  *
 248  * Returns 0 on a successful allocation of the metadata blocks in the
 249  * block group.
 250  */
 251 static int ext4_alloc_group_tables(struct super_block *sb,
 252                                 struct ext4_new_flex_group_data *flex_gd,
 253                                 int flexbg_size)
 254 {
 255         struct ext4_new_group_data *group_data = flex_gd->groups;
 256         ext4_fsblk_t start_blk;
 257         ext4_fsblk_t last_blk;
 258         ext4_group_t src_group;
 259         ext4_group_t bb_index = 0;
 260         ext4_group_t ib_index = 0;
 261         ext4_group_t it_index = 0;
 262         ext4_group_t group;
 263         ext4_group_t last_group;
 264         unsigned overhead;
 265         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 266         int i;
 267
 268         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 269
 270         src_group = group_data[0].group;
 271         last_group  = src_group + flex_gd->count - 1;
 272
 273         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 274                (last_group & ~(flexbg_size - 1))));
 275 next_group:
 276         group = group_data[0].group;
 277         if (src_group >= group_data[0].group + flex_gd->count)
 278                 return -ENOSPC;
 279         start_blk = ext4_group_first_block_no(sb, src_group);
 280         last_blk = start_blk + group_data[src_group - group].blocks_count;
 281
 282         overhead = ext4_group_overhead_blocks(sb, src_group);
 283
 284         start_blk += overhead;
 285
 286         /* We collect contiguous blocks as much as possible. */
 287         src_group++;
 288         for (; src_group <= last_group; src_group++) {
 289                 overhead = ext4_group_overhead_blocks(sb, src_group);
 290                 if (overhead == 0)
 291                         last_blk += group_data[src_group - group].blocks_count;
 292                 else
 293                         break;
 294         }
 295
 296         /* Allocate block bitmaps */
 297         for (; bb_index < flex_gd->count; bb_index++) {
 298                 if (start_blk >= last_blk)
 299                         goto next_group;
 300                 group_data[bb_index].block_bitmap = start_blk++;
 301                 group = ext4_get_group_number(sb, start_blk - 1);
 302                 group -= group_data[0].group;
 303                 group_data[group].mdata_blocks++;
 304                 flex_gd->bg_flags[group] &= uninit_mask;
 305         }
 306
 307         /* Allocate inode bitmaps */
 308         for (; ib_index < flex_gd->count; ib_index++) {
 309                 if (start_blk >= last_blk)
 310                         goto next_group;
 311                 group_data[ib_index].inode_bitmap = start_blk++;
 312                 group = ext4_get_group_number(sb, start_blk - 1);
 313                 group -= group_data[0].group;
 314                 group_data[group].mdata_blocks++;
 315                 flex_gd->bg_flags[group] &= uninit_mask;
 316         }
 317
 318         /* Allocate inode tables */
 319         for (; it_index < flex_gd->count; it_index++) {
 320                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 321                 ext4_fsblk_t next_group_start;
 322
 323                 if (start_blk + itb > last_blk)
 324                         goto next_group;
 325                 group_data[it_index].inode_table = start_blk;
 326                 group = ext4_get_group_number(sb, start_blk);
 327                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 328                 group -= group_data[0].group;
 329
 330                 if (start_blk + itb > next_group_start) {
 331                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 332                         overhead = start_blk + itb - next_group_start;
 333                         group_data[group + 1].mdata_blocks += overhead;
 334                         itb -= overhead;
 335                 }
 336
 337                 group_data[group].mdata_blocks += itb;
 338                 flex_gd->bg_flags[group] &= uninit_mask;
 339                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 340         }
 341
 342         /* Update free clusters count to exclude metadata blocks */
 343         for (i = 0; i < flex_gd->count; i++) {
 344                 group_data[i].free_clusters_count -=
 345                                 EXT4_NUM_B2C(EXT4_SB(sb),
 346                                              group_data[i].mdata_blocks);
 347         }
 348
 349         if (test_opt(sb, DEBUG)) {
 350                 int i;
 351                 group = group_data[0].group;
 352
 353                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 354                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 355                        flexbg_size);
 356
 357                 for (i = 0; i < flex_gd->count; i++) {
 358                         ext4_debug(
 359                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 360                                ext4_bg_has_super(sb, group + i) ? "normal" :
 361                                "no-super", group + i,
 362                                group_data[i].blocks_count,
 363                                group_data[i].free_clusters_count,
 364                                group_data[i].mdata_blocks);
 365                 }
 366         }
 367         return 0;
 368 }
 369
 370 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 371                                   ext4_fsblk_t blk)
 372 {
 373         struct buffer_head *bh;
 374         int err;
 375
 376         bh = sb_getblk(sb, blk);
 377         if (unlikely(!bh))
 378                 return ERR_PTR(-ENOMEM);
 379         BUFFER_TRACE(bh, "get_write_access");
 380         if ((err = ext4_journal_get_write_access(handle, bh))) {
 381                 brelse(bh);
 382                 bh = ERR_PTR(err);
 383         } else {
 384                 memset(bh->b_data, 0, sb->s_blocksize);
 385                 set_buffer_uptodate(bh);
 386         }
 387
 388         return bh;
 389 }
 390
 391 /*
 392  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 393  * If that fails, restart the transaction & regain write access for the
 394  * buffer head which is used for block_bitmap modifications.
 395  */
 396 static int extend_or_restart_transaction(handle_t *handle, int thresh)
 397 {
 398         int err;
 399
 400         if (ext4_handle_has_enough_credits(handle, thresh))
 401                 return 0;
 402
 403         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 404         if (err < 0)
 405                 return err;
 406         if (err) {
 407                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 408                 if (err)
 409                         return err;
 410         }
 411
 412         return 0;
 413 }
 414
 415 /*
 416  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 417  *
 418  * Helper function for ext4_setup_new_group_blocks() which set .
 419  *
 420  * @sb: super block
 421  * @handle: journal handle
 422  * @flex_gd: flex group data
 423  */
 424 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 425                         struct ext4_new_flex_group_data *flex_gd,
 426                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 427 {
 428         struct ext4_sb_info *sbi = EXT4_SB(sb);
 429         ext4_group_t count = last_cluster - first_cluster + 1;
 430         ext4_group_t count2;
 431
 432         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 433                    last_cluster);
 434         for (count2 = count; count > 0;
 435              count -= count2, first_cluster += count2) {
 436                 ext4_fsblk_t start;
 437                 struct buffer_head *bh;
 438                 ext4_group_t group;
 439                 int err;
 440
 441                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 442                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 443                 group -= flex_gd->groups[0].group;
 444
 445                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 446                 if (count2 > count)
 447                         count2 = count;
 448
 449                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 450                         BUG_ON(flex_gd->count > 1);
 451                         continue;
 452                 }
 453
 454                 err = extend_or_restart_transaction(handle, 1);
 455                 if (err)
 456                         return err;
 457
 458                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 459                 if (unlikely(!bh))
 460                         return -ENOMEM;
 461
 462                 BUFFER_TRACE(bh, "get_write_access");
 463                 err = ext4_journal_get_write_access(handle, bh);
 464                 if (err) {
 465                         brelse(bh);
 466                         return err;
 467                 }
 468                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 469                            first_cluster, first_cluster - start, count2);
 470                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 471
 472                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 473                 brelse(bh);
 474                 if (unlikely(err))
 475                         return err;
 476         }
 477
 478         return 0;
 479 }
 480
 481 /*
 482  * Set up the block and inode bitmaps, and the inode table for the new groups.
 483  * This doesn't need to be part of the main transaction, since we are only
 484  * changing blocks outside the actual filesystem.  We still do journaling to
 485  * ensure the recovery is correct in case of a failure just after resize.
 486  * If any part of this fails, we simply abort the resize.
 487  *
 488  * setup_new_flex_group_blocks handles a flex group as follow:
 489  *  1. copy super block and GDT, and initialize group tables if necessary.
 490  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 491  *     super block and GDT.
 492  *  2. allocate group tables in block bitmaps, that is, set bits in block
 493  *     bitmap for blocks taken by group tables.
 494  */
 495 static int setup_new_flex_group_blocks(struct super_block *sb,
 496                                 struct ext4_new_flex_group_data *flex_gd)
 497 {
 498         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 499         ext4_fsblk_t start;
 500         ext4_fsblk_t block;
 501         struct ext4_sb_info *sbi = EXT4_SB(sb);
 502         struct ext4_super_block *es = sbi->s_es;
 503         struct ext4_new_group_data *group_data = flex_gd->groups;
 504         __u16 *bg_flags = flex_gd->bg_flags;
 505         handle_t *handle;
 506         ext4_group_t group, count;
 507         struct buffer_head *bh = NULL;
 508         int reserved_gdb, i, j, err = 0, err2;
 509         int meta_bg;
 510
 511         BUG_ON(!flex_gd->count || !group_data ||
 512                group_data[0].group != sbi->s_groups_count);
 513
 514         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 515         meta_bg = ext4_has_feature_meta_bg(sb);
 516
 517         /* This transaction may be extended/restarted along the way */
 518         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 519         if (IS_ERR(handle))
 520                 return PTR_ERR(handle);
 521
 522         group = group_data[0].group;
 523         for (i = 0; i < flex_gd->count; i++, group++) {
 524                 unsigned long gdblocks;
 525                 ext4_grpblk_t overhead;
 526
 527                 gdblocks = ext4_bg_num_gdb(sb, group);
 528                 start = ext4_group_first_block_no(sb, group);
 529
 530                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 531                         goto handle_itb;
 532
 533                 if (meta_bg == 1) {
 534                         ext4_group_t first_group;
 535                         first_group = ext4_meta_bg_first_group(sb, group);
 536                         if (first_group != group + 1 &&
 537                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 538                                 goto handle_itb;
 539                 }
 540
 541                 block = start + ext4_bg_has_super(sb, group);
 542                 /* Copy all of the GDT blocks into the backup in this group */
 543                 for (j = 0; j < gdblocks; j++, block++) {
 544                         struct buffer_head *gdb;
 545
 546                         ext4_debug("update backup group %#04llx\n", block);
 547                         err = extend_or_restart_transaction(handle, 1);
 548                         if (err)
 549                                 goto out;
 550
 551                         gdb = sb_getblk(sb, block);
 552                         if (unlikely(!gdb)) {
 553                                 err = -ENOMEM;
 554                                 goto out;
 555                         }
 556
 557                         BUFFER_TRACE(gdb, "get_write_access");
 558                         err = ext4_journal_get_write_access(handle, gdb);
 559                         if (err) {
 560                                 brelse(gdb);
 561                                 goto out;
 562                         }
 563                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 564                                gdb->b_size);
 565                         set_buffer_uptodate(gdb);
 566
 567                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 568                         if (unlikely(err)) {
 569                                 brelse(gdb);
 570                                 goto out;
 571                         }
 572                         brelse(gdb);
 573                 }
 574
 575                 /* Zero out all of the reserved backup group descriptor
 576                  * table blocks
 577                  */
 578                 if (ext4_bg_has_super(sb, group)) {
 579                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 580                                         reserved_gdb, GFP_NOFS);
 581                         if (err)
 582                                 goto out;
 583                 }
 584
 585 handle_itb:
 586                 /* Initialize group tables of the grop @group */
 587                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 588                         goto handle_bb;
 589
 590                 /* Zero out all of the inode table blocks */
 591                 block = group_data[i].inode_table;
 592                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 593                            block, sbi->s_itb_per_group);
 594                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 595                                        GFP_NOFS);
 596                 if (err)
 597                         goto out;
 598
 599 handle_bb:
 600                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 601                         goto handle_ib;
 602
 603                 /* Initialize block bitmap of the @group */
 604                 block = group_data[i].block_bitmap;
 605                 err = extend_or_restart_transaction(handle, 1);
 606                 if (err)
 607                         goto out;
 608
 609                 bh = bclean(handle, sb, block);
 610                 if (IS_ERR(bh)) {
 611                         err = PTR_ERR(bh);
 612                         goto out;
 613                 }
 614                 overhead = ext4_group_overhead_blocks(sb, group);
 615                 if (overhead != 0) {
 616                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 617                                    start);
 618                         ext4_set_bits(bh->b_data, 0,
 619                                       EXT4_NUM_B2C(sbi, overhead));
 620                 }
 621                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 622                                      sb->s_blocksize * 8, bh->b_data);
 623                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 624                 brelse(bh);
 625                 if (err)
 626                         goto out;
 627
 628 handle_ib:
 629                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 630                         continue;
 631
 632                 /* Initialize inode bitmap of the @group */
 633                 block = group_data[i].inode_bitmap;
 634                 err = extend_or_restart_transaction(handle, 1);
 635                 if (err)
 636                         goto out;
 637                 /* Mark unused entries in inode bitmap used */
 638                 bh = bclean(handle, sb, block);
 639                 if (IS_ERR(bh)) {
 640                         err = PTR_ERR(bh);
 641                         goto out;
 642                 }
 643
 644                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 645                                      sb->s_blocksize * 8, bh->b_data);
 646                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 647                 brelse(bh);
 648                 if (err)
 649                         goto out;
 650         }
 651
 652         /* Mark group tables in block bitmap */
 653         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 654                 count = group_table_count[j];
 655                 start = (&group_data[0].block_bitmap)[j];
 656                 block = start;
 657                 for (i = 1; i < flex_gd->count; i++) {
 658                         block += group_table_count[j];
 659                         if (block == (&group_data[i].block_bitmap)[j]) {
 660                                 count += group_table_count[j];
 661                                 continue;
 662                         }
 663                         err = set_flexbg_block_bitmap(sb, handle,
 664                                                       flex_gd,
 665                                                       EXT4_B2C(sbi, start),
 666                                                       EXT4_B2C(sbi,
 667                                                                start + count
 668                                                                - 1));
 669                         if (err)
 670                                 goto out;
 671                         count = group_table_count[j];
 672                         start = (&group_data[i].block_bitmap)[j];
 673                         block = start;
 674                 }
 675
 676                 if (count) {
 677                         err = set_flexbg_block_bitmap(sb, handle,
 678                                                       flex_gd,
 679                                                       EXT4_B2C(sbi, start),
 680                                                       EXT4_B2C(sbi,
 681                                                                start + count
 682                                                                - 1));
 683                         if (err)
 684                                 goto out;
 685                 }
 686         }
 687
 688 out:
 689         err2 = ext4_journal_stop(handle);
 690         if (err2 && !err)
 691                 err = err2;
 692
 693         return err;
 694 }
 695
 696 /*
 697  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 698  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 699  * calling this for the first time.  In a sparse filesystem it will be the
 700  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 701  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 702  */
 703 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 704                                   unsigned *five, unsigned *seven)
 705 {
 706         unsigned *min = three;
 707         int mult = 3;
 708         unsigned ret;
 709
 710         if (!ext4_has_feature_sparse_super(sb)) {
 711                 ret = *min;
 712                 *min += 1;
 713                 return ret;
 714         }
 715
 716         if (*five < *min) {
 717                 min = five;
 718                 mult = 5;
 719         }
 720         if (*seven < *min) {
 721                 min = seven;
 722                 mult = 7;
 723         }
 724
 725         ret = *min;
 726         *min *= mult;
 727
 728         return ret;
 729 }
 730
 731 /*
 732  * Check that all of the backup GDT blocks are held in the primary GDT block.
 733  * It is assumed that they are stored in group order.  Returns the number of
 734  * groups in current filesystem that have BACKUPS, or -ve error code.
 735  */
 736 static int verify_reserved_gdb(struct super_block *sb,
 737                                ext4_group_t end,
 738                                struct buffer_head *primary)
 739 {
 740         const ext4_fsblk_t blk = primary->b_blocknr;
 741         unsigned three = 1;
 742         unsigned five = 5;
 743         unsigned seven = 7;
 744         unsigned grp;
 745         __le32 *p = (__le32 *)primary->b_data;
 746         int gdbackups = 0;
 747
 748         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 749                 if (le32_to_cpu(*p++) !=
 750                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 751                         ext4_warning(sb, "reserved GDT %llu"
 752                                      " missing grp %d (%llu)",
 753                                      blk, grp,
 754                                      grp *
 755                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 756                                      blk);
 757                         return -EINVAL;
 758                 }
 759                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 760                         return -EFBIG;
 761         }
 762
 763         return gdbackups;
 764 }
 765
 766 /*
 767  * Called when we need to bring a reserved group descriptor table block into
 768  * use from the resize inode.  The primary copy of the new GDT block currently
 769  * is an indirect block (under the double indirect block in the resize inode).
 770  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 771  * block, in group order.  Even though we know all the block numbers we need,
 772  * we check to ensure that the resize inode has actually reserved these blocks.
 773  *
 774  * Don't need to update the block bitmaps because the blocks are still in use.
 775  *
 776  * We get all of the error cases out of the way, so that we are sure to not
 777  * fail once we start modifying the data on disk, because JBD has no rollback.
 778  */
 779 static int add_new_gdb(handle_t *handle, struct inode *inode,
 780                        ext4_group_t group)
 781 {
 782         struct super_block *sb = inode->i_sb;
 783         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 784         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 785         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 786         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 787         struct buffer_head *dind = NULL;
 788         struct buffer_head *gdb_bh = NULL;
 789         int gdbackups;
 790         struct ext4_iloc iloc = { .bh = NULL };
 791         __le32 *data;
 792         int err;
 793
 794         if (test_opt(sb, DEBUG))
 795                 printk(KERN_DEBUG
 796                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 797                        gdb_num);
 798
 799         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 800         if (IS_ERR(gdb_bh))
 801                 return PTR_ERR(gdb_bh);
 802
 803         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 804         if (gdbackups < 0) {
 805                 err = gdbackups;
 806                 goto errout;
 807         }
 808
 809         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 810         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 811         if (IS_ERR(dind)) {
 812                 err = PTR_ERR(dind);
 813                 dind = NULL;
 814                 goto errout;
 815         }
 816
 817         data = (__le32 *)dind->b_data;
 818         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 819                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 820                              group, gdblock);
 821                 err = -EINVAL;
 822                 goto errout;
 823         }
 824
 825         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 826         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 827         if (unlikely(err))
 828                 goto errout;
 829
 830         BUFFER_TRACE(gdb_bh, "get_write_access");
 831         err = ext4_journal_get_write_access(handle, gdb_bh);
 832         if (unlikely(err))
 833                 goto errout;
 834
 835         BUFFER_TRACE(dind, "get_write_access");
 836         err = ext4_journal_get_write_access(handle, dind);
 837         if (unlikely(err))
 838                 ext4_std_error(sb, err);
 839
 840         /* ext4_reserve_inode_write() gets a reference on the iloc */
 841         err = ext4_reserve_inode_write(handle, inode, &iloc);
 842         if (unlikely(err))
 843                 goto errout;
 844
 845         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 846                                      sizeof(struct buffer_head *),
 847                                      GFP_NOFS);
 848         if (!n_group_desc) {
 849                 err = -ENOMEM;
 850                 ext4_warning(sb, "not enough memory for %lu groups",
 851                              gdb_num + 1);
 852                 goto errout;
 853         }
 854
 855         /*
 856          * Finally, we have all of the possible failures behind us...
 857          *
 858          * Remove new GDT block from inode double-indirect block and clear out
 859          * the new GDT block for use (which also "frees" the backup GDT blocks
 860          * from the reserved inode).  We don't need to change the bitmaps for
 861          * these blocks, because they are marked as in-use from being in the
 862          * reserved inode, and will become GDT blocks (primary and backup).
 863          */
 864         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 865         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 866         if (unlikely(err)) {
 867                 ext4_std_error(sb, err);
 868                 goto errout;
 869         }
 870         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 871                            (9 - EXT4_SB(sb)->s_cluster_bits);
 872         ext4_mark_iloc_dirty(handle, inode, &iloc);
 873         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 874         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 875         if (unlikely(err)) {
 876                 ext4_std_error(sb, err);
 877                 goto errout;
 878         }
 879         brelse(dind);
 880
 881         o_group_desc = EXT4_SB(sb)->s_group_desc;
 882         memcpy(n_group_desc, o_group_desc,
 883                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 884         n_group_desc[gdb_num] = gdb_bh;
 885         EXT4_SB(sb)->s_group_desc = n_group_desc;
 886         EXT4_SB(sb)->s_gdb_count++;
 887         kvfree(o_group_desc);
 888
 889         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 890         err = ext4_handle_dirty_super(handle, sb);
 891         if (err)
 892                 ext4_std_error(sb, err);
 893         return err;
 894 errout:
 895         kvfree(n_group_desc);
 896         brelse(iloc.bh);
 897         brelse(dind);
 898         brelse(gdb_bh);
 899
 900         ext4_debug("leaving with error %d\n", err);
 901         return err;
 902 }
 903
 904 /*
 905  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 906  */
 907 static int add_new_gdb_meta_bg(struct super_block *sb,
 908                                handle_t *handle, ext4_group_t group) {
 909         ext4_fsblk_t gdblock;
 910         struct buffer_head *gdb_bh;
 911         struct buffer_head **o_group_desc, **n_group_desc;
 912         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 913         int err;
 914
 915         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 916                    ext4_bg_has_super(sb, group);
 917         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 918         if (IS_ERR(gdb_bh))
 919                 return PTR_ERR(gdb_bh);
 920         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 921                                      sizeof(struct buffer_head *),
 922                                      GFP_NOFS);
 923         if (!n_group_desc) {
 924                 brelse(gdb_bh);
 925                 err = -ENOMEM;
 926                 ext4_warning(sb, "not enough memory for %lu groups",
 927                              gdb_num + 1);
 928                 return err;
 929         }
 930
 931         o_group_desc = EXT4_SB(sb)->s_group_desc;
 932         memcpy(n_group_desc, o_group_desc,
 933                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 934         n_group_desc[gdb_num] = gdb_bh;
 935
 936         BUFFER_TRACE(gdb_bh, "get_write_access");
 937         err = ext4_journal_get_write_access(handle, gdb_bh);
 938         if (err) {
 939                 kvfree(n_group_desc);
 940                 brelse(gdb_bh);
 941                 return err;
 942         }
 943
 944         EXT4_SB(sb)->s_group_desc = n_group_desc;
 945         EXT4_SB(sb)->s_gdb_count++;
 946         kvfree(o_group_desc);
 947         return err;
 948 }
 949
 950 /*
 951  * Called when we are adding a new group which has a backup copy of each of
 952  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 953  * We need to add these reserved backup GDT blocks to the resize inode, so
 954  * that they are kept for future resizing and not allocated to files.
 955  *
 956  * Each reserved backup GDT block will go into a different indirect block.
 957  * The indirect blocks are actually the primary reserved GDT blocks,
 958  * so we know in advance what their block numbers are.  We only get the
 959  * double-indirect block to verify it is pointing to the primary reserved
 960  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 961  * backup GDT blocks are stored in their reserved primary GDT block.
 962  */
 963 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 964                               ext4_group_t group)
 965 {
 966         struct super_block *sb = inode->i_sb;
 967         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 968         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 969         struct buffer_head **primary;
 970         struct buffer_head *dind;
 971         struct ext4_iloc iloc;
 972         ext4_fsblk_t blk;
 973         __le32 *data, *end;
 974         int gdbackups = 0;
 975         int res, i;
 976         int err;
 977
 978         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
 979         if (!primary)
 980                 return -ENOMEM;
 981
 982         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 983         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 984         if (IS_ERR(dind)) {
 985                 err = PTR_ERR(dind);
 986                 dind = NULL;
 987                 goto exit_free;
 988         }
 989
 990         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 991         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 992                                          EXT4_ADDR_PER_BLOCK(sb));
 993         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 994
 995         /* Get each reserved primary GDT block and verify it holds backups */
 996         for (res = 0; res < reserved_gdb; res++, blk++) {
 997                 if (le32_to_cpu(*data) != blk) {
 998                         ext4_warning(sb, "reserved block %llu"
 999                                      " not at offset %ld",
1000                                      blk,
1001                                      (long)(data - (__le32 *)dind->b_data));
1002                         err = -EINVAL;
1003                         goto exit_bh;
1004                 }
1005                 primary[res] = ext4_sb_bread(sb, blk, 0);
1006                 if (IS_ERR(primary[res])) {
1007                         err = PTR_ERR(primary[res]);
1008                         primary[res] = NULL;
1009                         goto exit_bh;
1010                 }
1011                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1012                 if (gdbackups < 0) {
1013                         brelse(primary[res]);
1014                         err = gdbackups;
1015                         goto exit_bh;
1016                 }
1017                 if (++data >= end)
1018                         data = (__le32 *)dind->b_data;
1019         }
1020
1021         for (i = 0; i < reserved_gdb; i++) {
1022                 BUFFER_TRACE(primary[i], "get_write_access");
1023                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1024                         goto exit_bh;
1025         }
1026
1027         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1028                 goto exit_bh;
1029
1030         /*
1031          * Finally we can add each of the reserved backup GDT blocks from
1032          * the new group to its reserved primary GDT block.
1033          */
1034         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1035         for (i = 0; i < reserved_gdb; i++) {
1036                 int err2;
1037                 data = (__le32 *)primary[i]->b_data;
1038                 /* printk("reserving backup %lu[%u] = %lu\n",
1039                        primary[i]->b_blocknr, gdbackups,
1040                        blk + primary[i]->b_blocknr); */
1041                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1042                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1043                 if (!err)
1044                         err = err2;
1045         }
1046
1047         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1048         ext4_mark_iloc_dirty(handle, inode, &iloc);
1049
1050 exit_bh:
1051         while (--res >= 0)
1052                 brelse(primary[res]);
1053         brelse(dind);
1054
1055 exit_free:
1056         kfree(primary);
1057
1058         return err;
1059 }
1060
1061 /*
1062  * Update the backup copies of the ext4 metadata.  These don't need to be part
1063  * of the main resize transaction, because e2fsck will re-write them if there
1064  * is a problem (basically only OOM will cause a problem).  However, we
1065  * _should_ update the backups if possible, in case the primary gets trashed
1066  * for some reason and we need to run e2fsck from a backup superblock.  The
1067  * important part is that the new block and inode counts are in the backup
1068  * superblocks, and the location of the new group metadata in the GDT backups.
1069  *
1070  * We do not need take the s_resize_lock for this, because these
1071  * blocks are not otherwise touched by the filesystem code when it is
1072  * mounted.  We don't need to worry about last changing from
1073  * sbi->s_groups_count, because the worst that can happen is that we
1074  * do not copy the full number of backups at this time.  The resize
1075  * which changed s_groups_count will backup again.
1076  */
1077 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1078                            int size, int meta_bg)
1079 {
1080         struct ext4_sb_info *sbi = EXT4_SB(sb);
1081         ext4_group_t last;
1082         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1083         unsigned three = 1;
1084         unsigned five = 5;
1085         unsigned seven = 7;
1086         ext4_group_t group = 0;
1087         int rest = sb->s_blocksize - size;
1088         handle_t *handle;
1089         int err = 0, err2;
1090
1091         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1092         if (IS_ERR(handle)) {
1093                 group = 1;
1094                 err = PTR_ERR(handle);
1095                 goto exit_err;
1096         }
1097
1098         if (meta_bg == 0) {
1099                 group = ext4_list_backups(sb, &three, &five, &seven);
1100                 last = sbi->s_groups_count;
1101         } else {
1102                 group = ext4_get_group_number(sb, blk_off) + 1;
1103                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1104         }
1105
1106         while (group < sbi->s_groups_count) {
1107                 struct buffer_head *bh;
1108                 ext4_fsblk_t backup_block;
1109
1110                 /* Out of journal space, and can't get more - abort - so sad */
1111                 if (ext4_handle_valid(handle) &&
1112                     handle->h_buffer_credits == 0 &&
1113                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1114                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1115                         break;
1116
1117                 if (meta_bg == 0)
1118                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1119                 else
1120                         backup_block = (ext4_group_first_block_no(sb, group) +
1121                                         ext4_bg_has_super(sb, group));
1122
1123                 bh = sb_getblk(sb, backup_block);
1124                 if (unlikely(!bh)) {
1125                         err = -ENOMEM;
1126                         break;
1127                 }
1128                 ext4_debug("update metadata backup %llu(+%llu)\n",
1129                            backup_block, backup_block -
1130                            ext4_group_first_block_no(sb, group));
1131                 BUFFER_TRACE(bh, "get_write_access");
1132                 if ((err = ext4_journal_get_write_access(handle, bh))) {
1133                         brelse(bh);
1134                         break;
1135                 }
1136                 lock_buffer(bh);
1137                 memcpy(bh->b_data, data, size);
1138                 if (rest)
1139                         memset(bh->b_data + size, 0, rest);
1140                 set_buffer_uptodate(bh);
1141                 unlock_buffer(bh);
1142                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1143                 if (unlikely(err))
1144                         ext4_std_error(sb, err);
1145                 brelse(bh);
1146
1147                 if (meta_bg == 0)
1148                         group = ext4_list_backups(sb, &three, &five, &seven);
1149                 else if (group == last)
1150                         break;
1151                 else
1152                         group = last;
1153         }
1154         if ((err2 = ext4_journal_stop(handle)) && !err)
1155                 err = err2;
1156
1157         /*
1158          * Ugh! Need to have e2fsck write the backup copies.  It is too
1159          * late to revert the resize, we shouldn't fail just because of
1160          * the backup copies (they are only needed in case of corruption).
1161          *
1162          * However, if we got here we have a journal problem too, so we
1163          * can't really start a transaction to mark the superblock.
1164          * Chicken out and just set the flag on the hope it will be written
1165          * to disk, and if not - we will simply wait until next fsck.
1166          */
1167 exit_err:
1168         if (err) {
1169                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1170                              "forcing fsck on next reboot", group, err);
1171                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1172                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1173                 mark_buffer_dirty(sbi->s_sbh);
1174         }
1175 }
1176
1177 /*
1178  * ext4_add_new_descs() adds @count group descriptor of groups
1179  * starting at @group
1180  *
1181  * @handle: journal handle
1182  * @sb: super block
1183  * @group: the group no. of the first group desc to be added
1184  * @resize_inode: the resize inode
1185  * @count: number of group descriptors to be added
1186  */
1187 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1188                               ext4_group_t group, struct inode *resize_inode,
1189                               ext4_group_t count)
1190 {
1191         struct ext4_sb_info *sbi = EXT4_SB(sb);
1192         struct ext4_super_block *es = sbi->s_es;
1193         struct buffer_head *gdb_bh;
1194         int i, gdb_off, gdb_num, err = 0;
1195         int meta_bg;
1196
1197         meta_bg = ext4_has_feature_meta_bg(sb);
1198         for (i = 0; i < count; i++, group++) {
1199                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1200                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1201
1202                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1203                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1204
1205                 /*
1206                  * We will only either add reserved group blocks to a backup group
1207                  * or remove reserved blocks for the first group in a new group block.
1208                  * Doing both would be mean more complex code, and sane people don't
1209                  * use non-sparse filesystems anymore.  This is already checked above.
1210                  */
1211                 if (gdb_off) {
1212                         gdb_bh = sbi->s_group_desc[gdb_num];
1213                         BUFFER_TRACE(gdb_bh, "get_write_access");
1214                         err = ext4_journal_get_write_access(handle, gdb_bh);
1215
1216                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1217                                 err = reserve_backup_gdb(handle, resize_inode, group);
1218                 } else if (meta_bg != 0) {
1219                         err = add_new_gdb_meta_bg(sb, handle, group);
1220                 } else {
1221                         err = add_new_gdb(handle, resize_inode, group);
1222                 }
1223                 if (err)
1224                         break;
1225         }
1226         return err;
1227 }
1228
1229 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1230 {
1231         struct buffer_head *bh = sb_getblk(sb, block);
1232         if (unlikely(!bh))
1233                 return NULL;
1234         if (!bh_uptodate_or_lock(bh)) {
1235                 if (bh_submit_read(bh) < 0) {
1236                         brelse(bh);
1237                         return NULL;
1238                 }
1239         }
1240
1241         return bh;
1242 }
1243
1244 static int ext4_set_bitmap_checksums(struct super_block *sb,
1245                                      ext4_group_t group,
1246                                      struct ext4_group_desc *gdp,
1247                                      struct ext4_new_group_data *group_data)
1248 {
1249         struct buffer_head *bh;
1250
1251         if (!ext4_has_metadata_csum(sb))
1252                 return 0;
1253
1254         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1255         if (!bh)
1256                 return -EIO;
1257         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1258                                    EXT4_INODES_PER_GROUP(sb) / 8);
1259         brelse(bh);
1260
1261         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1262         if (!bh)
1263                 return -EIO;
1264         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1265         brelse(bh);
1266
1267         return 0;
1268 }
1269
1270 /*
1271  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1272  */
1273 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1274                                 struct ext4_new_flex_group_data *flex_gd)
1275 {
1276         struct ext4_new_group_data      *group_data = flex_gd->groups;
1277         struct ext4_group_desc          *gdp;
1278         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1279         struct buffer_head              *gdb_bh;
1280         ext4_group_t                    group;
1281         __u16                           *bg_flags = flex_gd->bg_flags;
1282         int                             i, gdb_off, gdb_num, err = 0;
1283
1284
1285         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1286                 group = group_data->group;
1287
1288                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1289                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1290
1291                 /*
1292                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1293                  */
1294                 gdb_bh = sbi->s_group_desc[gdb_num];
1295                 /* Update group descriptor block for new group */
1296                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1297                                                  gdb_off * EXT4_DESC_SIZE(sb));
1298
1299                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1300                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1301                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1302                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1303                 if (err) {
1304                         ext4_std_error(sb, err);
1305                         break;
1306                 }
1307
1308                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1309                 ext4_free_group_clusters_set(sb, gdp,
1310                                              group_data->free_clusters_count);
1311                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1312                 if (ext4_has_group_desc_csum(sb))
1313                         ext4_itable_unused_set(sb, gdp,
1314                                                EXT4_INODES_PER_GROUP(sb));
1315                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1316                 ext4_group_desc_csum_set(sb, group, gdp);
1317
1318                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1319                 if (unlikely(err)) {
1320                         ext4_std_error(sb, err);
1321                         break;
1322                 }
1323
1324                 /*
1325                  * We can allocate memory for mb_alloc based on the new group
1326                  * descriptor
1327                  */
1328                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1329                 if (err)
1330                         break;
1331         }
1332         return err;
1333 }
1334
1335 /*
1336  * ext4_update_super() updates the super block so that the newly added
1337  * groups can be seen by the filesystem.
1338  *
1339  * @sb: super block
1340  * @flex_gd: new added groups
1341  */
1342 static void ext4_update_super(struct super_block *sb,
1343                              struct ext4_new_flex_group_data *flex_gd)
1344 {
1345         ext4_fsblk_t blocks_count = 0;
1346         ext4_fsblk_t free_blocks = 0;
1347         ext4_fsblk_t reserved_blocks = 0;
1348         struct ext4_new_group_data *group_data = flex_gd->groups;
1349         struct ext4_sb_info *sbi = EXT4_SB(sb);
1350         struct ext4_super_block *es = sbi->s_es;
1351         int i;
1352
1353         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1354         /*
1355          * Make the new blocks and inodes valid next.  We do this before
1356          * increasing the group count so that once the group is enabled,
1357          * all of its blocks and inodes are already valid.
1358          *
1359          * We always allocate group-by-group, then block-by-block or
1360          * inode-by-inode within a group, so enabling these
1361          * blocks/inodes before the group is live won't actually let us
1362          * allocate the new space yet.
1363          */
1364         for (i = 0; i < flex_gd->count; i++) {
1365                 blocks_count += group_data[i].blocks_count;
1366                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1367         }
1368
1369         reserved_blocks = ext4_r_blocks_count(es) * 100;
1370         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1371         reserved_blocks *= blocks_count;
1372         do_div(reserved_blocks, 100);
1373
1374         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1375         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1376         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1377                      flex_gd->count);
1378         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1379                      flex_gd->count);
1380
1381         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1382         /*
1383          * We need to protect s_groups_count against other CPUs seeing
1384          * inconsistent state in the superblock.
1385          *
1386          * The precise rules we use are:
1387          *
1388          * * Writers must perform a smp_wmb() after updating all
1389          *   dependent data and before modifying the groups count
1390          *
1391          * * Readers must perform an smp_rmb() after reading the groups
1392          *   count and before reading any dependent data.
1393          *
1394          * NB. These rules can be relaxed when checking the group count
1395          * while freeing data, as we can only allocate from a block
1396          * group after serialising against the group count, and we can
1397          * only then free after serialising in turn against that
1398          * allocation.
1399          */
1400         smp_wmb();
1401
1402         /* Update the global fs size fields */
1403         sbi->s_groups_count += flex_gd->count;
1404         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1405                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1406
1407         /* Update the reserved block counts only once the new group is
1408          * active. */
1409         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1410                                 reserved_blocks);
1411
1412         /* Update the free space counts */
1413         percpu_counter_add(&sbi->s_freeclusters_counter,
1414                            EXT4_NUM_B2C(sbi, free_blocks));
1415         percpu_counter_add(&sbi->s_freeinodes_counter,
1416                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1417
1418         ext4_debug("free blocks count %llu",
1419                    percpu_counter_read(&sbi->s_freeclusters_counter));
1420         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1421                 ext4_group_t flex_group;
1422                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1423                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1424                              &sbi->s_flex_groups[flex_group].free_clusters);
1425                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1426                            &sbi->s_flex_groups[flex_group].free_inodes);
1427         }
1428
1429         /*
1430          * Update the fs overhead information
1431          */
1432         ext4_calculate_overhead(sb);
1433
1434         if (test_opt(sb, DEBUG))
1435                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1436                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1437                        blocks_count, free_blocks, reserved_blocks);
1438 }
1439
1440 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1441  * _before_ we start modifying the filesystem, because we cannot abort the
1442  * transaction and not have it write the data to disk.
1443  */
1444 static int ext4_flex_group_add(struct super_block *sb,
1445                                struct inode *resize_inode,
1446                                struct ext4_new_flex_group_data *flex_gd)
1447 {
1448         struct ext4_sb_info *sbi = EXT4_SB(sb);
1449         struct ext4_super_block *es = sbi->s_es;
1450         ext4_fsblk_t o_blocks_count;
1451         ext4_grpblk_t last;
1452         ext4_group_t group;
1453         handle_t *handle;
1454         unsigned reserved_gdb;
1455         int err = 0, err2 = 0, credit;
1456
1457         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1458
1459         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1460         o_blocks_count = ext4_blocks_count(es);
1461         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1462         BUG_ON(last);
1463
1464         err = setup_new_flex_group_blocks(sb, flex_gd);
1465         if (err)
1466                 goto exit;
1467         /*
1468          * We will always be modifying at least the superblock and  GDT
1469          * blocks.  If we are adding a group past the last current GDT block,
1470          * we will also modify the inode and the dindirect block.  If we
1471          * are adding a group with superblock/GDT backups  we will also
1472          * modify each of the reserved GDT dindirect blocks.
1473          */
1474         credit = 3;     /* sb, resize inode, resize inode dindirect */
1475         /* GDT blocks */
1476         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1477         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1478         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1479         if (IS_ERR(handle)) {
1480                 err = PTR_ERR(handle);
1481                 goto exit;
1482         }
1483
1484         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1485         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1486         if (err)
1487                 goto exit_journal;
1488
1489         group = flex_gd->groups[0].group;
1490         BUG_ON(group != sbi->s_groups_count);
1491         err = ext4_add_new_descs(handle, sb, group,
1492                                 resize_inode, flex_gd->count);
1493         if (err)
1494                 goto exit_journal;
1495
1496         err = ext4_setup_new_descs(handle, sb, flex_gd);
1497         if (err)
1498                 goto exit_journal;
1499
1500         ext4_update_super(sb, flex_gd);
1501
1502         err = ext4_handle_dirty_super(handle, sb);
1503
1504 exit_journal:
1505         err2 = ext4_journal_stop(handle);
1506         if (!err)
1507                 err = err2;
1508
1509         if (!err) {
1510                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1511                 int gdb_num_end = ((group + flex_gd->count - 1) /
1512                                    EXT4_DESC_PER_BLOCK(sb));
1513                 int meta_bg = ext4_has_feature_meta_bg(sb);
1514                 sector_t old_gdb = 0;
1515
1516                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1517                                sizeof(struct ext4_super_block), 0);
1518                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1519                         struct buffer_head *gdb_bh;
1520
1521                         gdb_bh = sbi->s_group_desc[gdb_num];
1522                         if (old_gdb == gdb_bh->b_blocknr)
1523                                 continue;
1524                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1525                                        gdb_bh->b_size, meta_bg);
1526                         old_gdb = gdb_bh->b_blocknr;
1527                 }
1528         }
1529 exit:
1530         return err;
1531 }
1532
1533 static int ext4_setup_next_flex_gd(struct super_block *sb,
1534                                     struct ext4_new_flex_group_data *flex_gd,
1535                                     ext4_fsblk_t n_blocks_count,
1536                                     unsigned long flexbg_size)
1537 {
1538         struct ext4_sb_info *sbi = EXT4_SB(sb);
1539         struct ext4_super_block *es = sbi->s_es;
1540         struct ext4_new_group_data *group_data = flex_gd->groups;
1541         ext4_fsblk_t o_blocks_count;
1542         ext4_group_t n_group;
1543         ext4_group_t group;
1544         ext4_group_t last_group;
1545         ext4_grpblk_t last;
1546         ext4_grpblk_t clusters_per_group;
1547         unsigned long i;
1548
1549         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1550
1551         o_blocks_count = ext4_blocks_count(es);
1552
1553         if (o_blocks_count == n_blocks_count)
1554                 return 0;
1555
1556         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1557         BUG_ON(last);
1558         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1559
1560         last_group = group | (flexbg_size - 1);
1561         if (last_group > n_group)
1562                 last_group = n_group;
1563
1564         flex_gd->count = last_group - group + 1;
1565
1566         for (i = 0; i < flex_gd->count; i++) {
1567                 int overhead;
1568
1569                 group_data[i].group = group + i;
1570                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1571                 overhead = ext4_group_overhead_blocks(sb, group + i);
1572                 group_data[i].mdata_blocks = overhead;
1573                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1574                 if (ext4_has_group_desc_csum(sb)) {
1575                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1576                                                EXT4_BG_INODE_UNINIT;
1577                         if (!test_opt(sb, INIT_INODE_TABLE))
1578                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1579                 } else
1580                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1581         }
1582
1583         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1584                 /* We need to initialize block bitmap of last group. */
1585                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1586
1587         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1588                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1589                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1590                                                        last - 1;
1591         }
1592
1593         return 1;
1594 }
1595
1596 /* Add group descriptor data to an existing or new group descriptor block.
1597  * Ensure we handle all possible error conditions _before_ we start modifying
1598  * the filesystem, because we cannot abort the transaction and not have it
1599  * write the data to disk.
1600  *
1601  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1602  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1603  *
1604  * We only need to hold the superblock lock while we are actually adding
1605  * in the new group's counts to the superblock.  Prior to that we have
1606  * not really "added" the group at all.  We re-check that we are still
1607  * adding in the last group in case things have changed since verifying.
1608  */
1609 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1610 {
1611         struct ext4_new_flex_group_data flex_gd;
1612         struct ext4_sb_info *sbi = EXT4_SB(sb);
1613         struct ext4_super_block *es = sbi->s_es;
1614         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1615                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1616         struct inode *inode = NULL;
1617         int gdb_off;
1618         int err;
1619         __u16 bg_flags = 0;
1620
1621         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1622
1623         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1624                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1625                 return -EPERM;
1626         }
1627
1628         if (ext4_blocks_count(es) + input->blocks_count <
1629             ext4_blocks_count(es)) {
1630                 ext4_warning(sb, "blocks_count overflow");
1631                 return -EINVAL;
1632         }
1633
1634         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1635             le32_to_cpu(es->s_inodes_count)) {
1636                 ext4_warning(sb, "inodes_count overflow");
1637                 return -EINVAL;
1638         }
1639
1640         if (reserved_gdb || gdb_off == 0) {
1641                 if (!ext4_has_feature_resize_inode(sb) ||
1642                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1643                         ext4_warning(sb,
1644                                      "No reserved GDT blocks, can't resize");
1645                         return -EPERM;
1646                 }
1647                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1648                 if (IS_ERR(inode)) {
1649                         ext4_warning(sb, "Error opening resize inode");
1650                         return PTR_ERR(inode);
1651                 }
1652         }
1653
1654
1655         err = verify_group_input(sb, input);
1656         if (err)
1657                 goto out;
1658
1659         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1660         if (err)
1661                 goto out;
1662
1663         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1664         if (err)
1665                 goto out;
1666
1667         flex_gd.count = 1;
1668         flex_gd.groups = input;
1669         flex_gd.bg_flags = &bg_flags;
1670         err = ext4_flex_group_add(sb, inode, &flex_gd);
1671 out:
1672         iput(inode);
1673         return err;
1674 } /* ext4_group_add */
1675
1676 /*
1677  * extend a group without checking assuming that checking has been done.
1678  */
1679 static int ext4_group_extend_no_check(struct super_block *sb,
1680                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1681 {
1682         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1683         handle_t *handle;
1684         int err = 0, err2;
1685
1686         /* We will update the superblock, one block bitmap, and
1687          * one group descriptor via ext4_group_add_blocks().
1688          */
1689         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1690         if (IS_ERR(handle)) {
1691                 err = PTR_ERR(handle);
1692                 ext4_warning(sb, "error %d on journal start", err);
1693                 return err;
1694         }
1695
1696         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1697         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1698         if (err) {
1699                 ext4_warning(sb, "error %d on journal write access", err);
1700                 goto errout;
1701         }
1702
1703         ext4_blocks_count_set(es, o_blocks_count + add);
1704         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1705         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1706                    o_blocks_count + add);
1707         /* We add the blocks to the bitmap and set the group need init bit */
1708         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1709         if (err)
1710                 goto errout;
1711         ext4_handle_dirty_super(handle, sb);
1712         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1713                    o_blocks_count + add);
1714 errout:
1715         err2 = ext4_journal_stop(handle);
1716         if (err2 && !err)
1717                 err = err2;
1718
1719         if (!err) {
1720                 if (test_opt(sb, DEBUG))
1721                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1722                                "blocks\n", ext4_blocks_count(es));
1723                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1724                                (char *)es, sizeof(struct ext4_super_block), 0);
1725         }
1726         return err;
1727 }
1728
1729 /*
1730  * Extend the filesystem to the new number of blocks specified.  This entry
1731  * point is only used to extend the current filesystem to the end of the last
1732  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1733  * for emergencies (because it has no dependencies on reserved blocks).
1734  *
1735  * If we _really_ wanted, we could use default values to call ext4_group_add()
1736  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1737  * GDT blocks are reserved to grow to the desired size.
1738  */
1739 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1740                       ext4_fsblk_t n_blocks_count)
1741 {
1742         ext4_fsblk_t o_blocks_count;
1743         ext4_grpblk_t last;
1744         ext4_grpblk_t add;
1745         struct buffer_head *bh;
1746         int err;
1747         ext4_group_t group;
1748
1749         o_blocks_count = ext4_blocks_count(es);
1750
1751         if (test_opt(sb, DEBUG))
1752                 ext4_msg(sb, KERN_DEBUG,
1753                          "extending last group from %llu to %llu blocks",
1754                          o_blocks_count, n_blocks_count);
1755
1756         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1757                 return 0;
1758
1759         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1760                 ext4_msg(sb, KERN_ERR,
1761                          "filesystem too large to resize to %llu blocks safely",
1762                          n_blocks_count);
1763                 if (sizeof(sector_t) < 8)
1764                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1765                 return -EINVAL;
1766         }
1767
1768         if (n_blocks_count < o_blocks_count) {
1769                 ext4_warning(sb, "can't shrink FS - resize aborted");
1770                 return -EINVAL;
1771         }
1772
1773         /* Handle the remaining blocks in the last group only. */
1774         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1775
1776         if (last == 0) {
1777                 ext4_warning(sb, "need to use ext2online to resize further");
1778                 return -EPERM;
1779         }
1780
1781         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1782
1783         if (o_blocks_count + add < o_blocks_count) {
1784                 ext4_warning(sb, "blocks_count overflow");
1785                 return -EINVAL;
1786         }
1787
1788         if (o_blocks_count + add > n_blocks_count)
1789                 add = n_blocks_count - o_blocks_count;
1790
1791         if (o_blocks_count + add < n_blocks_count)
1792                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1793                              o_blocks_count + add, add);
1794
1795         /* See if the device is actually as big as what was requested */
1796         bh = sb_bread(sb, o_blocks_count + add - 1);
1797         if (!bh) {
1798                 ext4_warning(sb, "can't read last block, resize aborted");
1799                 return -ENOSPC;
1800         }
1801         brelse(bh);
1802
1803         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1804         return err;
1805 } /* ext4_group_extend */
1806
1807
1808 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1809 {
1810         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1811 }
1812
1813 /*
1814  * Release the resize inode and drop the resize_inode feature if there
1815  * are no more reserved gdt blocks, and then convert the file system
1816  * to enable meta_bg
1817  */
1818 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1819 {
1820         handle_t *handle;
1821         struct ext4_sb_info *sbi = EXT4_SB(sb);
1822         struct ext4_super_block *es = sbi->s_es;
1823         struct ext4_inode_info *ei = EXT4_I(inode);
1824         ext4_fsblk_t nr;
1825         int i, ret, err = 0;
1826         int credits = 1;
1827
1828         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1829         if (inode) {
1830                 if (es->s_reserved_gdt_blocks) {
1831                         ext4_error(sb, "Unexpected non-zero "
1832                                    "s_reserved_gdt_blocks");
1833                         return -EPERM;
1834                 }
1835
1836                 /* Do a quick sanity check of the resize inode */
1837                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1838                                              (9 - sbi->s_cluster_bits)))
1839                         goto invalid_resize_inode;
1840                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1841                         if (i == EXT4_DIND_BLOCK) {
1842                                 if (ei->i_data[i])
1843                                         continue;
1844                                 else
1845                                         goto invalid_resize_inode;
1846                         }
1847                         if (ei->i_data[i])
1848                                 goto invalid_resize_inode;
1849                 }
1850                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1851         }
1852
1853         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1854         if (IS_ERR(handle))
1855                 return PTR_ERR(handle);
1856
1857         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1858         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1859         if (err)
1860                 goto errout;
1861
1862         ext4_clear_feature_resize_inode(sb);
1863         ext4_set_feature_meta_bg(sb);
1864         sbi->s_es->s_first_meta_bg =
1865                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1866
1867         err = ext4_handle_dirty_super(handle, sb);
1868         if (err) {
1869                 ext4_std_error(sb, err);
1870                 goto errout;
1871         }
1872
1873         if (inode) {
1874                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1875                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1876                                  EXT4_FREE_BLOCKS_METADATA |
1877                                  EXT4_FREE_BLOCKS_FORGET);
1878                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1879                 inode->i_blocks = 0;
1880
1881                 err = ext4_mark_inode_dirty(handle, inode);
1882                 if (err)
1883                         ext4_std_error(sb, err);
1884         }
1885
1886 errout:
1887         ret = ext4_journal_stop(handle);
1888         if (!err)
1889                 err = ret;
1890         return ret;
1891
1892 invalid_resize_inode:
1893         ext4_error(sb, "corrupted/inconsistent resize inode");
1894         return -EINVAL;
1895 }
1896
1897 /*
1898  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1899  *
1900  * @sb: super block of the fs to be resized
1901  * @n_blocks_count: the number of blocks resides in the resized fs
1902  */
1903 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1904 {
1905         struct ext4_new_flex_group_data *flex_gd = NULL;
1906         struct ext4_sb_info *sbi = EXT4_SB(sb);
1907         struct ext4_super_block *es = sbi->s_es;
1908         struct buffer_head *bh;
1909         struct inode *resize_inode = NULL;
1910         ext4_grpblk_t add, offset;
1911         unsigned long n_desc_blocks;
1912         unsigned long o_desc_blocks;
1913         ext4_group_t o_group;
1914         ext4_group_t n_group;
1915         ext4_fsblk_t o_blocks_count;
1916         ext4_fsblk_t n_blocks_count_retry = 0;
1917         unsigned long last_update_time = 0;
1918         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1919         int meta_bg;
1920
1921         /* See if the device is actually as big as what was requested */
1922         bh = sb_bread(sb, n_blocks_count - 1);
1923         if (!bh) {
1924                 ext4_warning(sb, "can't read last block, resize aborted");
1925                 return -ENOSPC;
1926         }
1927         brelse(bh);
1928
1929 retry:
1930         o_blocks_count = ext4_blocks_count(es);
1931
1932         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1933                  "to %llu blocks", o_blocks_count, n_blocks_count);
1934
1935         if (n_blocks_count < o_blocks_count) {
1936                 /* On-line shrinking not supported */
1937                 ext4_warning(sb, "can't shrink FS - resize aborted");
1938                 return -EINVAL;
1939         }
1940
1941         if (n_blocks_count == o_blocks_count)
1942                 /* Nothing need to do */
1943                 return 0;
1944
1945         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1946         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1947                 ext4_warning(sb, "resize would cause inodes_count overflow");
1948                 return -EINVAL;
1949         }
1950         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1951
1952         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1953         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1954
1955         meta_bg = ext4_has_feature_meta_bg(sb);
1956
1957         if (ext4_has_feature_resize_inode(sb)) {
1958                 if (meta_bg) {
1959                         ext4_error(sb, "resize_inode and meta_bg enabled "
1960                                    "simultaneously");
1961                         return -EINVAL;
1962                 }
1963                 if (n_desc_blocks > o_desc_blocks +
1964                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1965                         n_blocks_count_retry = n_blocks_count;
1966                         n_desc_blocks = o_desc_blocks +
1967                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1968                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1969                         n_blocks_count = (ext4_fsblk_t)n_group *
1970                                 EXT4_BLOCKS_PER_GROUP(sb) +
1971                                 le32_to_cpu(es->s_first_data_block);
1972                         n_group--; /* set to last group number */
1973                 }
1974
1975                 if (!resize_inode)
1976                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
1977                                                  EXT4_IGET_SPECIAL);
1978                 if (IS_ERR(resize_inode)) {
1979                         ext4_warning(sb, "Error opening resize inode");
1980                         return PTR_ERR(resize_inode);
1981                 }
1982         }
1983
1984         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1985                 err = ext4_convert_meta_bg(sb, resize_inode);
1986                 if (err)
1987                         goto out;
1988                 if (resize_inode) {
1989                         iput(resize_inode);
1990                         resize_inode = NULL;
1991                 }
1992                 if (n_blocks_count_retry) {
1993                         n_blocks_count = n_blocks_count_retry;
1994                         n_blocks_count_retry = 0;
1995                         goto retry;
1996                 }
1997         }
1998
1999         /*
2000          * Make sure the last group has enough space so that it's
2001          * guaranteed to have enough space for all metadata blocks
2002          * that it might need to hold.  (We might not need to store
2003          * the inode table blocks in the last block group, but there
2004          * will be cases where this might be needed.)
2005          */
2006         if ((ext4_group_first_block_no(sb, n_group) +
2007              ext4_group_overhead_blocks(sb, n_group) + 2 +
2008              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2009                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2010                 n_group--;
2011                 n_blocks_count_retry = 0;
2012                 if (resize_inode) {
2013                         iput(resize_inode);
2014                         resize_inode = NULL;
2015                 }
2016                 goto retry;
2017         }
2018
2019         /* extend the last group */
2020         if (n_group == o_group)
2021                 add = n_blocks_count - o_blocks_count;
2022         else
2023                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2024         if (add > 0) {
2025                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2026                 if (err)
2027                         goto out;
2028         }
2029
2030         if (ext4_blocks_count(es) == n_blocks_count)
2031                 goto out;
2032
2033         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2034         if (err)
2035                 goto out;
2036
2037         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2038         if (err)
2039                 goto out;
2040
2041         flex_gd = alloc_flex_gd(flexbg_size);
2042         if (flex_gd == NULL) {
2043                 err = -ENOMEM;
2044                 goto out;
2045         }
2046
2047         /* Add flex groups. Note that a regular group is a
2048          * flex group with 1 group.
2049          */
2050         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2051                                               flexbg_size)) {
2052                 if (jiffies - last_update_time > HZ * 10) {
2053                         if (last_update_time)
2054                                 ext4_msg(sb, KERN_INFO,
2055                                          "resized to %llu blocks",
2056                                          ext4_blocks_count(es));
2057                         last_update_time = jiffies;
2058                 }
2059                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2060                         break;
2061                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2062                 if (unlikely(err))
2063                         break;
2064         }
2065
2066         if (!err && n_blocks_count_retry) {
2067                 n_blocks_count = n_blocks_count_retry;
2068                 n_blocks_count_retry = 0;
2069                 free_flex_gd(flex_gd);
2070                 flex_gd = NULL;
2071                 if (resize_inode) {
2072                         iput(resize_inode);
2073                         resize_inode = NULL;
2074                 }
2075                 goto retry;
2076         }
2077
2078 out:
2079         if (flex_gd)
2080                 free_flex_gd(flex_gd);
2081         if (resize_inode != NULL)
2082                 iput(resize_inode);
2083         if (err)
2084                 ext4_warning(sb, "error (%d) occurred during "
2085                              "file system resize", err);
2086         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2087                  ext4_blocks_count(es));
2088         return err;
2089 }