fs/ext4/resize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/resize.c
   4  *
   5  * Support for resizing an ext4 filesystem while it is mounted.
   6  *
   7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17
  18 #include "ext4_jbd2.h"
  19
  20 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 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
 392 {
 393         return ext4_journal_ensure_credits_fn(handle, credits,
 394                 EXT4_MAX_TRANS_DATA, 0, 0);
 395 }
 396
 397 /*
 398  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 399  *
 400  * Helper function for ext4_setup_new_group_blocks() which set .
 401  *
 402  * @sb: super block
 403  * @handle: journal handle
 404  * @flex_gd: flex group data
 405  */
 406 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 407                         struct ext4_new_flex_group_data *flex_gd,
 408                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 409 {
 410         struct ext4_sb_info *sbi = EXT4_SB(sb);
 411         ext4_group_t count = last_cluster - first_cluster + 1;
 412         ext4_group_t count2;
 413
 414         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 415                    last_cluster);
 416         for (count2 = count; count > 0;
 417              count -= count2, first_cluster += count2) {
 418                 ext4_fsblk_t start;
 419                 struct buffer_head *bh;
 420                 ext4_group_t group;
 421                 int err;
 422
 423                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 424                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 425                 group -= flex_gd->groups[0].group;
 426
 427                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 428                 if (count2 > count)
 429                         count2 = count;
 430
 431                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 432                         BUG_ON(flex_gd->count > 1);
 433                         continue;
 434                 }
 435
 436                 err = ext4_resize_ensure_credits_batch(handle, 1);
 437                 if (err < 0)
 438                         return err;
 439
 440                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 441                 if (unlikely(!bh))
 442                         return -ENOMEM;
 443
 444                 BUFFER_TRACE(bh, "get_write_access");
 445                 err = ext4_journal_get_write_access(handle, bh);
 446                 if (err) {
 447                         brelse(bh);
 448                         return err;
 449                 }
 450                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 451                            first_cluster, first_cluster - start, count2);
 452                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 453
 454                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 455                 brelse(bh);
 456                 if (unlikely(err))
 457                         return err;
 458         }
 459
 460         return 0;
 461 }
 462
 463 /*
 464  * Set up the block and inode bitmaps, and the inode table for the new groups.
 465  * This doesn't need to be part of the main transaction, since we are only
 466  * changing blocks outside the actual filesystem.  We still do journaling to
 467  * ensure the recovery is correct in case of a failure just after resize.
 468  * If any part of this fails, we simply abort the resize.
 469  *
 470  * setup_new_flex_group_blocks handles a flex group as follow:
 471  *  1. copy super block and GDT, and initialize group tables if necessary.
 472  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 473  *     super block and GDT.
 474  *  2. allocate group tables in block bitmaps, that is, set bits in block
 475  *     bitmap for blocks taken by group tables.
 476  */
 477 static int setup_new_flex_group_blocks(struct super_block *sb,
 478                                 struct ext4_new_flex_group_data *flex_gd)
 479 {
 480         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 481         ext4_fsblk_t start;
 482         ext4_fsblk_t block;
 483         struct ext4_sb_info *sbi = EXT4_SB(sb);
 484         struct ext4_super_block *es = sbi->s_es;
 485         struct ext4_new_group_data *group_data = flex_gd->groups;
 486         __u16 *bg_flags = flex_gd->bg_flags;
 487         handle_t *handle;
 488         ext4_group_t group, count;
 489         struct buffer_head *bh = NULL;
 490         int reserved_gdb, i, j, err = 0, err2;
 491         int meta_bg;
 492
 493         BUG_ON(!flex_gd->count || !group_data ||
 494                group_data[0].group != sbi->s_groups_count);
 495
 496         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 497         meta_bg = ext4_has_feature_meta_bg(sb);
 498
 499         /* This transaction may be extended/restarted along the way */
 500         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 501         if (IS_ERR(handle))
 502                 return PTR_ERR(handle);
 503
 504         group = group_data[0].group;
 505         for (i = 0; i < flex_gd->count; i++, group++) {
 506                 unsigned long gdblocks;
 507                 ext4_grpblk_t overhead;
 508
 509                 gdblocks = ext4_bg_num_gdb(sb, group);
 510                 start = ext4_group_first_block_no(sb, group);
 511
 512                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 513                         goto handle_itb;
 514
 515                 if (meta_bg == 1) {
 516                         ext4_group_t first_group;
 517                         first_group = ext4_meta_bg_first_group(sb, group);
 518                         if (first_group != group + 1 &&
 519                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 520                                 goto handle_itb;
 521                 }
 522
 523                 block = start + ext4_bg_has_super(sb, group);
 524                 /* Copy all of the GDT blocks into the backup in this group */
 525                 for (j = 0; j < gdblocks; j++, block++) {
 526                         struct buffer_head *gdb;
 527
 528                         ext4_debug("update backup group %#04llx\n", block);
 529                         err = ext4_resize_ensure_credits_batch(handle, 1);
 530                         if (err < 0)
 531                                 goto out;
 532
 533                         gdb = sb_getblk(sb, block);
 534                         if (unlikely(!gdb)) {
 535                                 err = -ENOMEM;
 536                                 goto out;
 537                         }
 538
 539                         BUFFER_TRACE(gdb, "get_write_access");
 540                         err = ext4_journal_get_write_access(handle, gdb);
 541                         if (err) {
 542                                 brelse(gdb);
 543                                 goto out;
 544                         }
 545                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 546                                gdb->b_size);
 547                         set_buffer_uptodate(gdb);
 548
 549                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 550                         if (unlikely(err)) {
 551                                 brelse(gdb);
 552                                 goto out;
 553                         }
 554                         brelse(gdb);
 555                 }
 556
 557                 /* Zero out all of the reserved backup group descriptor
 558                  * table blocks
 559                  */
 560                 if (ext4_bg_has_super(sb, group)) {
 561                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 562                                         reserved_gdb, GFP_NOFS);
 563                         if (err)
 564                                 goto out;
 565                 }
 566
 567 handle_itb:
 568                 /* Initialize group tables of the grop @group */
 569                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 570                         goto handle_bb;
 571
 572                 /* Zero out all of the inode table blocks */
 573                 block = group_data[i].inode_table;
 574                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 575                            block, sbi->s_itb_per_group);
 576                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 577                                        GFP_NOFS);
 578                 if (err)
 579                         goto out;
 580
 581 handle_bb:
 582                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 583                         goto handle_ib;
 584
 585                 /* Initialize block bitmap of the @group */
 586                 block = group_data[i].block_bitmap;
 587                 err = ext4_resize_ensure_credits_batch(handle, 1);
 588                 if (err < 0)
 589                         goto out;
 590
 591                 bh = bclean(handle, sb, block);
 592                 if (IS_ERR(bh)) {
 593                         err = PTR_ERR(bh);
 594                         goto out;
 595                 }
 596                 overhead = ext4_group_overhead_blocks(sb, group);
 597                 if (overhead != 0) {
 598                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 599                                    start);
 600                         ext4_set_bits(bh->b_data, 0,
 601                                       EXT4_NUM_B2C(sbi, overhead));
 602                 }
 603                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 604                                      sb->s_blocksize * 8, bh->b_data);
 605                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 606                 brelse(bh);
 607                 if (err)
 608                         goto out;
 609
 610 handle_ib:
 611                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 612                         continue;
 613
 614                 /* Initialize inode bitmap of the @group */
 615                 block = group_data[i].inode_bitmap;
 616                 err = ext4_resize_ensure_credits_batch(handle, 1);
 617                 if (err < 0)
 618                         goto out;
 619                 /* Mark unused entries in inode bitmap used */
 620                 bh = bclean(handle, sb, block);
 621                 if (IS_ERR(bh)) {
 622                         err = PTR_ERR(bh);
 623                         goto out;
 624                 }
 625
 626                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 627                                      sb->s_blocksize * 8, bh->b_data);
 628                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 629                 brelse(bh);
 630                 if (err)
 631                         goto out;
 632         }
 633
 634         /* Mark group tables in block bitmap */
 635         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 636                 count = group_table_count[j];
 637                 start = (&group_data[0].block_bitmap)[j];
 638                 block = start;
 639                 for (i = 1; i < flex_gd->count; i++) {
 640                         block += group_table_count[j];
 641                         if (block == (&group_data[i].block_bitmap)[j]) {
 642                                 count += group_table_count[j];
 643                                 continue;
 644                         }
 645                         err = set_flexbg_block_bitmap(sb, handle,
 646                                                       flex_gd,
 647                                                       EXT4_B2C(sbi, start),
 648                                                       EXT4_B2C(sbi,
 649                                                                start + count
 650                                                                - 1));
 651                         if (err)
 652                                 goto out;
 653                         count = group_table_count[j];
 654                         start = (&group_data[i].block_bitmap)[j];
 655                         block = start;
 656                 }
 657
 658                 if (count) {
 659                         err = set_flexbg_block_bitmap(sb, handle,
 660                                                       flex_gd,
 661                                                       EXT4_B2C(sbi, start),
 662                                                       EXT4_B2C(sbi,
 663                                                                start + count
 664                                                                - 1));
 665                         if (err)
 666                                 goto out;
 667                 }
 668         }
 669
 670 out:
 671         err2 = ext4_journal_stop(handle);
 672         if (err2 && !err)
 673                 err = err2;
 674
 675         return err;
 676 }
 677
 678 /*
 679  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 680  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 681  * calling this for the first time.  In a sparse filesystem it will be the
 682  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 683  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 684  */
 685 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 686                                   unsigned *five, unsigned *seven)
 687 {
 688         unsigned *min = three;
 689         int mult = 3;
 690         unsigned ret;
 691
 692         if (!ext4_has_feature_sparse_super(sb)) {
 693                 ret = *min;
 694                 *min += 1;
 695                 return ret;
 696         }
 697
 698         if (*five < *min) {
 699                 min = five;
 700                 mult = 5;
 701         }
 702         if (*seven < *min) {
 703                 min = seven;
 704                 mult = 7;
 705         }
 706
 707         ret = *min;
 708         *min *= mult;
 709
 710         return ret;
 711 }
 712
 713 /*
 714  * Check that all of the backup GDT blocks are held in the primary GDT block.
 715  * It is assumed that they are stored in group order.  Returns the number of
 716  * groups in current filesystem that have BACKUPS, or -ve error code.
 717  */
 718 static int verify_reserved_gdb(struct super_block *sb,
 719                                ext4_group_t end,
 720                                struct buffer_head *primary)
 721 {
 722         const ext4_fsblk_t blk = primary->b_blocknr;
 723         unsigned three = 1;
 724         unsigned five = 5;
 725         unsigned seven = 7;
 726         unsigned grp;
 727         __le32 *p = (__le32 *)primary->b_data;
 728         int gdbackups = 0;
 729
 730         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 731                 if (le32_to_cpu(*p++) !=
 732                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 733                         ext4_warning(sb, "reserved GDT %llu"
 734                                      " missing grp %d (%llu)",
 735                                      blk, grp,
 736                                      grp *
 737                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 738                                      blk);
 739                         return -EINVAL;
 740                 }
 741                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 742                         return -EFBIG;
 743         }
 744
 745         return gdbackups;
 746 }
 747
 748 /*
 749  * Called when we need to bring a reserved group descriptor table block into
 750  * use from the resize inode.  The primary copy of the new GDT block currently
 751  * is an indirect block (under the double indirect block in the resize inode).
 752  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 753  * block, in group order.  Even though we know all the block numbers we need,
 754  * we check to ensure that the resize inode has actually reserved these blocks.
 755  *
 756  * Don't need to update the block bitmaps because the blocks are still in use.
 757  *
 758  * We get all of the error cases out of the way, so that we are sure to not
 759  * fail once we start modifying the data on disk, because JBD has no rollback.
 760  */
 761 static int add_new_gdb(handle_t *handle, struct inode *inode,
 762                        ext4_group_t group)
 763 {
 764         struct super_block *sb = inode->i_sb;
 765         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 766         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 767         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 768         struct buffer_head **o_group_desc, **n_group_desc = NULL;
 769         struct buffer_head *dind = NULL;
 770         struct buffer_head *gdb_bh = NULL;
 771         int gdbackups;
 772         struct ext4_iloc iloc = { .bh = NULL };
 773         __le32 *data;
 774         int err;
 775
 776         if (test_opt(sb, DEBUG))
 777                 printk(KERN_DEBUG
 778                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 779                        gdb_num);
 780
 781         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 782         if (IS_ERR(gdb_bh))
 783                 return PTR_ERR(gdb_bh);
 784
 785         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 786         if (gdbackups < 0) {
 787                 err = gdbackups;
 788                 goto errout;
 789         }
 790
 791         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 792         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 793         if (IS_ERR(dind)) {
 794                 err = PTR_ERR(dind);
 795                 dind = NULL;
 796                 goto errout;
 797         }
 798
 799         data = (__le32 *)dind->b_data;
 800         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 801                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 802                              group, gdblock);
 803                 err = -EINVAL;
 804                 goto errout;
 805         }
 806
 807         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 808         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 809         if (unlikely(err))
 810                 goto errout;
 811
 812         BUFFER_TRACE(gdb_bh, "get_write_access");
 813         err = ext4_journal_get_write_access(handle, gdb_bh);
 814         if (unlikely(err))
 815                 goto errout;
 816
 817         BUFFER_TRACE(dind, "get_write_access");
 818         err = ext4_journal_get_write_access(handle, dind);
 819         if (unlikely(err))
 820                 ext4_std_error(sb, err);
 821
 822         /* ext4_reserve_inode_write() gets a reference on the iloc */
 823         err = ext4_reserve_inode_write(handle, inode, &iloc);
 824         if (unlikely(err))
 825                 goto errout;
 826
 827         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 828                                 GFP_KERNEL);
 829         if (!n_group_desc) {
 830                 err = -ENOMEM;
 831                 ext4_warning(sb, "not enough memory for %lu groups",
 832                              gdb_num + 1);
 833                 goto errout;
 834         }
 835
 836         /*
 837          * Finally, we have all of the possible failures behind us...
 838          *
 839          * Remove new GDT block from inode double-indirect block and clear out
 840          * the new GDT block for use (which also "frees" the backup GDT blocks
 841          * from the reserved inode).  We don't need to change the bitmaps for
 842          * these blocks, because they are marked as in-use from being in the
 843          * reserved inode, and will become GDT blocks (primary and backup).
 844          */
 845         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 846         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 847         if (unlikely(err)) {
 848                 ext4_std_error(sb, err);
 849                 goto errout;
 850         }
 851         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 852                            (9 - EXT4_SB(sb)->s_cluster_bits);
 853         ext4_mark_iloc_dirty(handle, inode, &iloc);
 854         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 855         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 856         if (unlikely(err)) {
 857                 ext4_std_error(sb, err);
 858                 iloc.bh = NULL;
 859                 goto errout;
 860         }
 861         brelse(dind);
 862
 863         o_group_desc = EXT4_SB(sb)->s_group_desc;
 864         memcpy(n_group_desc, o_group_desc,
 865                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 866         n_group_desc[gdb_num] = gdb_bh;
 867         EXT4_SB(sb)->s_group_desc = n_group_desc;
 868         EXT4_SB(sb)->s_gdb_count++;
 869         kvfree(o_group_desc);
 870
 871         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 872         err = ext4_handle_dirty_super(handle, sb);
 873         if (err)
 874                 ext4_std_error(sb, err);
 875         return err;
 876 errout:
 877         kvfree(n_group_desc);
 878         brelse(iloc.bh);
 879         brelse(dind);
 880         brelse(gdb_bh);
 881
 882         ext4_debug("leaving with error %d\n", err);
 883         return err;
 884 }
 885
 886 /*
 887  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 888  */
 889 static int add_new_gdb_meta_bg(struct super_block *sb,
 890                                handle_t *handle, ext4_group_t group) {
 891         ext4_fsblk_t gdblock;
 892         struct buffer_head *gdb_bh;
 893         struct buffer_head **o_group_desc, **n_group_desc;
 894         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 895         int err;
 896
 897         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 898                    ext4_bg_has_super(sb, group);
 899         gdb_bh = ext4_sb_bread(sb, gdblock, 0);
 900         if (IS_ERR(gdb_bh))
 901                 return PTR_ERR(gdb_bh);
 902         n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
 903                                 GFP_KERNEL);
 904         if (!n_group_desc) {
 905                 brelse(gdb_bh);
 906                 err = -ENOMEM;
 907                 ext4_warning(sb, "not enough memory for %lu groups",
 908                              gdb_num + 1);
 909                 return err;
 910         }
 911
 912         o_group_desc = EXT4_SB(sb)->s_group_desc;
 913         memcpy(n_group_desc, o_group_desc,
 914                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 915         n_group_desc[gdb_num] = gdb_bh;
 916
 917         BUFFER_TRACE(gdb_bh, "get_write_access");
 918         err = ext4_journal_get_write_access(handle, gdb_bh);
 919         if (err) {
 920                 kvfree(n_group_desc);
 921                 brelse(gdb_bh);
 922                 return err;
 923         }
 924
 925         EXT4_SB(sb)->s_group_desc = n_group_desc;
 926         EXT4_SB(sb)->s_gdb_count++;
 927         kvfree(o_group_desc);
 928         return err;
 929 }
 930
 931 /*
 932  * Called when we are adding a new group which has a backup copy of each of
 933  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 934  * We need to add these reserved backup GDT blocks to the resize inode, so
 935  * that they are kept for future resizing and not allocated to files.
 936  *
 937  * Each reserved backup GDT block will go into a different indirect block.
 938  * The indirect blocks are actually the primary reserved GDT blocks,
 939  * so we know in advance what their block numbers are.  We only get the
 940  * double-indirect block to verify it is pointing to the primary reserved
 941  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 942  * backup GDT blocks are stored in their reserved primary GDT block.
 943  */
 944 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 945                               ext4_group_t group)
 946 {
 947         struct super_block *sb = inode->i_sb;
 948         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 949         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 950         struct buffer_head **primary;
 951         struct buffer_head *dind;
 952         struct ext4_iloc iloc;
 953         ext4_fsblk_t blk;
 954         __le32 *data, *end;
 955         int gdbackups = 0;
 956         int res, i;
 957         int err;
 958
 959         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
 960         if (!primary)
 961                 return -ENOMEM;
 962
 963         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 964         dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
 965         if (IS_ERR(dind)) {
 966                 err = PTR_ERR(dind);
 967                 dind = NULL;
 968                 goto exit_free;
 969         }
 970
 971         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 972         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 973                                          EXT4_ADDR_PER_BLOCK(sb));
 974         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 975
 976         /* Get each reserved primary GDT block and verify it holds backups */
 977         for (res = 0; res < reserved_gdb; res++, blk++) {
 978                 if (le32_to_cpu(*data) != blk) {
 979                         ext4_warning(sb, "reserved block %llu"
 980                                      " not at offset %ld",
 981                                      blk,
 982                                      (long)(data - (__le32 *)dind->b_data));
 983                         err = -EINVAL;
 984                         goto exit_bh;
 985                 }
 986                 primary[res] = ext4_sb_bread(sb, blk, 0);
 987                 if (IS_ERR(primary[res])) {
 988                         err = PTR_ERR(primary[res]);
 989                         primary[res] = NULL;
 990                         goto exit_bh;
 991                 }
 992                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 993                 if (gdbackups < 0) {
 994                         brelse(primary[res]);
 995                         err = gdbackups;
 996                         goto exit_bh;
 997                 }
 998                 if (++data >= end)
 999                         data = (__le32 *)dind->b_data;
1000         }
1001
1002         for (i = 0; i < reserved_gdb; i++) {
1003                 BUFFER_TRACE(primary[i], "get_write_access");
1004                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1005                         goto exit_bh;
1006         }
1007
1008         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1009                 goto exit_bh;
1010
1011         /*
1012          * Finally we can add each of the reserved backup GDT blocks from
1013          * the new group to its reserved primary GDT block.
1014          */
1015         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1016         for (i = 0; i < reserved_gdb; i++) {
1017                 int err2;
1018                 data = (__le32 *)primary[i]->b_data;
1019                 /* printk("reserving backup %lu[%u] = %lu\n",
1020                        primary[i]->b_blocknr, gdbackups,
1021                        blk + primary[i]->b_blocknr); */
1022                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1023                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1024                 if (!err)
1025                         err = err2;
1026         }
1027
1028         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1029         ext4_mark_iloc_dirty(handle, inode, &iloc);
1030
1031 exit_bh:
1032         while (--res >= 0)
1033                 brelse(primary[res]);
1034         brelse(dind);
1035
1036 exit_free:
1037         kfree(primary);
1038
1039         return err;
1040 }
1041
1042 /*
1043  * Update the backup copies of the ext4 metadata.  These don't need to be part
1044  * of the main resize transaction, because e2fsck will re-write them if there
1045  * is a problem (basically only OOM will cause a problem).  However, we
1046  * _should_ update the backups if possible, in case the primary gets trashed
1047  * for some reason and we need to run e2fsck from a backup superblock.  The
1048  * important part is that the new block and inode counts are in the backup
1049  * superblocks, and the location of the new group metadata in the GDT backups.
1050  *
1051  * We do not need take the s_resize_lock for this, because these
1052  * blocks are not otherwise touched by the filesystem code when it is
1053  * mounted.  We don't need to worry about last changing from
1054  * sbi->s_groups_count, because the worst that can happen is that we
1055  * do not copy the full number of backups at this time.  The resize
1056  * which changed s_groups_count will backup again.
1057  */
1058 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1059                            int size, int meta_bg)
1060 {
1061         struct ext4_sb_info *sbi = EXT4_SB(sb);
1062         ext4_group_t last;
1063         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1064         unsigned three = 1;
1065         unsigned five = 5;
1066         unsigned seven = 7;
1067         ext4_group_t group = 0;
1068         int rest = sb->s_blocksize - size;
1069         handle_t *handle;
1070         int err = 0, err2;
1071
1072         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1073         if (IS_ERR(handle)) {
1074                 group = 1;
1075                 err = PTR_ERR(handle);
1076                 goto exit_err;
1077         }
1078
1079         if (meta_bg == 0) {
1080                 group = ext4_list_backups(sb, &three, &five, &seven);
1081                 last = sbi->s_groups_count;
1082         } else {
1083                 group = ext4_get_group_number(sb, blk_off) + 1;
1084                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1085         }
1086
1087         while (group < sbi->s_groups_count) {
1088                 struct buffer_head *bh;
1089                 ext4_fsblk_t backup_block;
1090
1091                 /* Out of journal space, and can't get more - abort - so sad */
1092                 err = ext4_resize_ensure_credits_batch(handle, 1);
1093                 if (err < 0)
1094                         break;
1095
1096                 if (meta_bg == 0)
1097                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1098                 else
1099                         backup_block = (ext4_group_first_block_no(sb, group) +
1100                                         ext4_bg_has_super(sb, group));
1101
1102                 bh = sb_getblk(sb, backup_block);
1103                 if (unlikely(!bh)) {
1104                         err = -ENOMEM;
1105                         break;
1106                 }
1107                 ext4_debug("update metadata backup %llu(+%llu)\n",
1108                            backup_block, backup_block -
1109                            ext4_group_first_block_no(sb, group));
1110                 BUFFER_TRACE(bh, "get_write_access");
1111                 if ((err = ext4_journal_get_write_access(handle, bh))) {
1112                         brelse(bh);
1113                         break;
1114                 }
1115                 lock_buffer(bh);
1116                 memcpy(bh->b_data, data, size);
1117                 if (rest)
1118                         memset(bh->b_data + size, 0, rest);
1119                 set_buffer_uptodate(bh);
1120                 unlock_buffer(bh);
1121                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1122                 if (unlikely(err))
1123                         ext4_std_error(sb, err);
1124                 brelse(bh);
1125
1126                 if (meta_bg == 0)
1127                         group = ext4_list_backups(sb, &three, &five, &seven);
1128                 else if (group == last)
1129                         break;
1130                 else
1131                         group = last;
1132         }
1133         if ((err2 = ext4_journal_stop(handle)) && !err)
1134                 err = err2;
1135
1136         /*
1137          * Ugh! Need to have e2fsck write the backup copies.  It is too
1138          * late to revert the resize, we shouldn't fail just because of
1139          * the backup copies (they are only needed in case of corruption).
1140          *
1141          * However, if we got here we have a journal problem too, so we
1142          * can't really start a transaction to mark the superblock.
1143          * Chicken out and just set the flag on the hope it will be written
1144          * to disk, and if not - we will simply wait until next fsck.
1145          */
1146 exit_err:
1147         if (err) {
1148                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1149                              "forcing fsck on next reboot", group, err);
1150                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1151                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1152                 mark_buffer_dirty(sbi->s_sbh);
1153         }
1154 }
1155
1156 /*
1157  * ext4_add_new_descs() adds @count group descriptor of groups
1158  * starting at @group
1159  *
1160  * @handle: journal handle
1161  * @sb: super block
1162  * @group: the group no. of the first group desc to be added
1163  * @resize_inode: the resize inode
1164  * @count: number of group descriptors to be added
1165  */
1166 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1167                               ext4_group_t group, struct inode *resize_inode,
1168                               ext4_group_t count)
1169 {
1170         struct ext4_sb_info *sbi = EXT4_SB(sb);
1171         struct ext4_super_block *es = sbi->s_es;
1172         struct buffer_head *gdb_bh;
1173         int i, gdb_off, gdb_num, err = 0;
1174         int meta_bg;
1175
1176         meta_bg = ext4_has_feature_meta_bg(sb);
1177         for (i = 0; i < count; i++, group++) {
1178                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1179                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1180
1181                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1182                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1183
1184                 /*
1185                  * We will only either add reserved group blocks to a backup group
1186                  * or remove reserved blocks for the first group in a new group block.
1187                  * Doing both would be mean more complex code, and sane people don't
1188                  * use non-sparse filesystems anymore.  This is already checked above.
1189                  */
1190                 if (gdb_off) {
1191                         gdb_bh = sbi->s_group_desc[gdb_num];
1192                         BUFFER_TRACE(gdb_bh, "get_write_access");
1193                         err = ext4_journal_get_write_access(handle, gdb_bh);
1194
1195                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1196                                 err = reserve_backup_gdb(handle, resize_inode, group);
1197                 } else if (meta_bg != 0) {
1198                         err = add_new_gdb_meta_bg(sb, handle, group);
1199                 } else {
1200                         err = add_new_gdb(handle, resize_inode, group);
1201                 }
1202                 if (err)
1203                         break;
1204         }
1205         return err;
1206 }
1207
1208 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1209 {
1210         struct buffer_head *bh = sb_getblk(sb, block);
1211         if (unlikely(!bh))
1212                 return NULL;
1213         if (!bh_uptodate_or_lock(bh)) {
1214                 if (bh_submit_read(bh) < 0) {
1215                         brelse(bh);
1216                         return NULL;
1217                 }
1218         }
1219
1220         return bh;
1221 }
1222
1223 static int ext4_set_bitmap_checksums(struct super_block *sb,
1224                                      ext4_group_t group,
1225                                      struct ext4_group_desc *gdp,
1226                                      struct ext4_new_group_data *group_data)
1227 {
1228         struct buffer_head *bh;
1229
1230         if (!ext4_has_metadata_csum(sb))
1231                 return 0;
1232
1233         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1234         if (!bh)
1235                 return -EIO;
1236         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1237                                    EXT4_INODES_PER_GROUP(sb) / 8);
1238         brelse(bh);
1239
1240         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1241         if (!bh)
1242                 return -EIO;
1243         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1244         brelse(bh);
1245
1246         return 0;
1247 }
1248
1249 /*
1250  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1251  */
1252 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1253                                 struct ext4_new_flex_group_data *flex_gd)
1254 {
1255         struct ext4_new_group_data      *group_data = flex_gd->groups;
1256         struct ext4_group_desc          *gdp;
1257         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1258         struct buffer_head              *gdb_bh;
1259         ext4_group_t                    group;
1260         __u16                           *bg_flags = flex_gd->bg_flags;
1261         int                             i, gdb_off, gdb_num, err = 0;
1262
1263
1264         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1265                 group = group_data->group;
1266
1267                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1268                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1269
1270                 /*
1271                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1272                  */
1273                 gdb_bh = sbi->s_group_desc[gdb_num];
1274                 /* Update group descriptor block for new group */
1275                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1276                                                  gdb_off * EXT4_DESC_SIZE(sb));
1277
1278                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1279                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1280                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1281                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1282                 if (err) {
1283                         ext4_std_error(sb, err);
1284                         break;
1285                 }
1286
1287                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1288                 ext4_free_group_clusters_set(sb, gdp,
1289                                              group_data->free_clusters_count);
1290                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1291                 if (ext4_has_group_desc_csum(sb))
1292                         ext4_itable_unused_set(sb, gdp,
1293                                                EXT4_INODES_PER_GROUP(sb));
1294                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1295                 ext4_group_desc_csum_set(sb, group, gdp);
1296
1297                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1298                 if (unlikely(err)) {
1299                         ext4_std_error(sb, err);
1300                         break;
1301                 }
1302
1303                 /*
1304                  * We can allocate memory for mb_alloc based on the new group
1305                  * descriptor
1306                  */
1307                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1308                 if (err)
1309                         break;
1310         }
1311         return err;
1312 }
1313
1314 /*
1315  * ext4_update_super() updates the super block so that the newly added
1316  * groups can be seen by the filesystem.
1317  *
1318  * @sb: super block
1319  * @flex_gd: new added groups
1320  */
1321 static void ext4_update_super(struct super_block *sb,
1322                              struct ext4_new_flex_group_data *flex_gd)
1323 {
1324         ext4_fsblk_t blocks_count = 0;
1325         ext4_fsblk_t free_blocks = 0;
1326         ext4_fsblk_t reserved_blocks = 0;
1327         struct ext4_new_group_data *group_data = flex_gd->groups;
1328         struct ext4_sb_info *sbi = EXT4_SB(sb);
1329         struct ext4_super_block *es = sbi->s_es;
1330         int i;
1331
1332         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1333         /*
1334          * Make the new blocks and inodes valid next.  We do this before
1335          * increasing the group count so that once the group is enabled,
1336          * all of its blocks and inodes are already valid.
1337          *
1338          * We always allocate group-by-group, then block-by-block or
1339          * inode-by-inode within a group, so enabling these
1340          * blocks/inodes before the group is live won't actually let us
1341          * allocate the new space yet.
1342          */
1343         for (i = 0; i < flex_gd->count; i++) {
1344                 blocks_count += group_data[i].blocks_count;
1345                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1346         }
1347
1348         reserved_blocks = ext4_r_blocks_count(es) * 100;
1349         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1350         reserved_blocks *= blocks_count;
1351         do_div(reserved_blocks, 100);
1352
1353         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1354         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1355         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1356                      flex_gd->count);
1357         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1358                      flex_gd->count);
1359
1360         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1361         /*
1362          * We need to protect s_groups_count against other CPUs seeing
1363          * inconsistent state in the superblock.
1364          *
1365          * The precise rules we use are:
1366          *
1367          * * Writers must perform a smp_wmb() after updating all
1368          *   dependent data and before modifying the groups count
1369          *
1370          * * Readers must perform an smp_rmb() after reading the groups
1371          *   count and before reading any dependent data.
1372          *
1373          * NB. These rules can be relaxed when checking the group count
1374          * while freeing data, as we can only allocate from a block
1375          * group after serialising against the group count, and we can
1376          * only then free after serialising in turn against that
1377          * allocation.
1378          */
1379         smp_wmb();
1380
1381         /* Update the global fs size fields */
1382         sbi->s_groups_count += flex_gd->count;
1383         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1384                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1385
1386         /* Update the reserved block counts only once the new group is
1387          * active. */
1388         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1389                                 reserved_blocks);
1390
1391         /* Update the free space counts */
1392         percpu_counter_add(&sbi->s_freeclusters_counter,
1393                            EXT4_NUM_B2C(sbi, free_blocks));
1394         percpu_counter_add(&sbi->s_freeinodes_counter,
1395                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1396
1397         ext4_debug("free blocks count %llu",
1398                    percpu_counter_read(&sbi->s_freeclusters_counter));
1399         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1400                 ext4_group_t flex_group;
1401                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1402                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1403                              &sbi->s_flex_groups[flex_group].free_clusters);
1404                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1405                            &sbi->s_flex_groups[flex_group].free_inodes);
1406         }
1407
1408         /*
1409          * Update the fs overhead information
1410          */
1411         ext4_calculate_overhead(sb);
1412
1413         if (test_opt(sb, DEBUG))
1414                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1415                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1416                        blocks_count, free_blocks, reserved_blocks);
1417 }
1418
1419 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1420  * _before_ we start modifying the filesystem, because we cannot abort the
1421  * transaction and not have it write the data to disk.
1422  */
1423 static int ext4_flex_group_add(struct super_block *sb,
1424                                struct inode *resize_inode,
1425                                struct ext4_new_flex_group_data *flex_gd)
1426 {
1427         struct ext4_sb_info *sbi = EXT4_SB(sb);
1428         struct ext4_super_block *es = sbi->s_es;
1429         ext4_fsblk_t o_blocks_count;
1430         ext4_grpblk_t last;
1431         ext4_group_t group;
1432         handle_t *handle;
1433         unsigned reserved_gdb;
1434         int err = 0, err2 = 0, credit;
1435
1436         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1437
1438         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1439         o_blocks_count = ext4_blocks_count(es);
1440         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1441         BUG_ON(last);
1442
1443         err = setup_new_flex_group_blocks(sb, flex_gd);
1444         if (err)
1445                 goto exit;
1446         /*
1447          * We will always be modifying at least the superblock and  GDT
1448          * blocks.  If we are adding a group past the last current GDT block,
1449          * we will also modify the inode and the dindirect block.  If we
1450          * are adding a group with superblock/GDT backups  we will also
1451          * modify each of the reserved GDT dindirect blocks.
1452          */
1453         credit = 3;     /* sb, resize inode, resize inode dindirect */
1454         /* GDT blocks */
1455         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1456         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1457         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1458         if (IS_ERR(handle)) {
1459                 err = PTR_ERR(handle);
1460                 goto exit;
1461         }
1462
1463         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1464         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1465         if (err)
1466                 goto exit_journal;
1467
1468         group = flex_gd->groups[0].group;
1469         BUG_ON(group != sbi->s_groups_count);
1470         err = ext4_add_new_descs(handle, sb, group,
1471                                 resize_inode, flex_gd->count);
1472         if (err)
1473                 goto exit_journal;
1474
1475         err = ext4_setup_new_descs(handle, sb, flex_gd);
1476         if (err)
1477                 goto exit_journal;
1478
1479         ext4_update_super(sb, flex_gd);
1480
1481         err = ext4_handle_dirty_super(handle, sb);
1482
1483 exit_journal:
1484         err2 = ext4_journal_stop(handle);
1485         if (!err)
1486                 err = err2;
1487
1488         if (!err) {
1489                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1490                 int gdb_num_end = ((group + flex_gd->count - 1) /
1491                                    EXT4_DESC_PER_BLOCK(sb));
1492                 int meta_bg = ext4_has_feature_meta_bg(sb);
1493                 sector_t old_gdb = 0;
1494
1495                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1496                                sizeof(struct ext4_super_block), 0);
1497                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1498                         struct buffer_head *gdb_bh;
1499
1500                         gdb_bh = sbi->s_group_desc[gdb_num];
1501                         if (old_gdb == gdb_bh->b_blocknr)
1502                                 continue;
1503                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1504                                        gdb_bh->b_size, meta_bg);
1505                         old_gdb = gdb_bh->b_blocknr;
1506                 }
1507         }
1508 exit:
1509         return err;
1510 }
1511
1512 static int ext4_setup_next_flex_gd(struct super_block *sb,
1513                                     struct ext4_new_flex_group_data *flex_gd,
1514                                     ext4_fsblk_t n_blocks_count,
1515                                     unsigned long flexbg_size)
1516 {
1517         struct ext4_sb_info *sbi = EXT4_SB(sb);
1518         struct ext4_super_block *es = sbi->s_es;
1519         struct ext4_new_group_data *group_data = flex_gd->groups;
1520         ext4_fsblk_t o_blocks_count;
1521         ext4_group_t n_group;
1522         ext4_group_t group;
1523         ext4_group_t last_group;
1524         ext4_grpblk_t last;
1525         ext4_grpblk_t clusters_per_group;
1526         unsigned long i;
1527
1528         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1529
1530         o_blocks_count = ext4_blocks_count(es);
1531
1532         if (o_blocks_count == n_blocks_count)
1533                 return 0;
1534
1535         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1536         BUG_ON(last);
1537         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1538
1539         last_group = group | (flexbg_size - 1);
1540         if (last_group > n_group)
1541                 last_group = n_group;
1542
1543         flex_gd->count = last_group - group + 1;
1544
1545         for (i = 0; i < flex_gd->count; i++) {
1546                 int overhead;
1547
1548                 group_data[i].group = group + i;
1549                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1550                 overhead = ext4_group_overhead_blocks(sb, group + i);
1551                 group_data[i].mdata_blocks = overhead;
1552                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1553                 if (ext4_has_group_desc_csum(sb)) {
1554                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1555                                                EXT4_BG_INODE_UNINIT;
1556                         if (!test_opt(sb, INIT_INODE_TABLE))
1557                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1558                 } else
1559                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1560         }
1561
1562         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1563                 /* We need to initialize block bitmap of last group. */
1564                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1565
1566         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1567                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1568                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1569                                                        last - 1;
1570         }
1571
1572         return 1;
1573 }
1574
1575 /* Add group descriptor data to an existing or new group descriptor block.
1576  * Ensure we handle all possible error conditions _before_ we start modifying
1577  * the filesystem, because we cannot abort the transaction and not have it
1578  * write the data to disk.
1579  *
1580  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1581  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1582  *
1583  * We only need to hold the superblock lock while we are actually adding
1584  * in the new group's counts to the superblock.  Prior to that we have
1585  * not really "added" the group at all.  We re-check that we are still
1586  * adding in the last group in case things have changed since verifying.
1587  */
1588 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1589 {
1590         struct ext4_new_flex_group_data flex_gd;
1591         struct ext4_sb_info *sbi = EXT4_SB(sb);
1592         struct ext4_super_block *es = sbi->s_es;
1593         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1594                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1595         struct inode *inode = NULL;
1596         int gdb_off;
1597         int err;
1598         __u16 bg_flags = 0;
1599
1600         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1601
1602         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1603                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1604                 return -EPERM;
1605         }
1606
1607         if (ext4_blocks_count(es) + input->blocks_count <
1608             ext4_blocks_count(es)) {
1609                 ext4_warning(sb, "blocks_count overflow");
1610                 return -EINVAL;
1611         }
1612
1613         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1614             le32_to_cpu(es->s_inodes_count)) {
1615                 ext4_warning(sb, "inodes_count overflow");
1616                 return -EINVAL;
1617         }
1618
1619         if (reserved_gdb || gdb_off == 0) {
1620                 if (!ext4_has_feature_resize_inode(sb) ||
1621                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1622                         ext4_warning(sb,
1623                                      "No reserved GDT blocks, can't resize");
1624                         return -EPERM;
1625                 }
1626                 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1627                 if (IS_ERR(inode)) {
1628                         ext4_warning(sb, "Error opening resize inode");
1629                         return PTR_ERR(inode);
1630                 }
1631         }
1632
1633
1634         err = verify_group_input(sb, input);
1635         if (err)
1636                 goto out;
1637
1638         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1639         if (err)
1640                 goto out;
1641
1642         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1643         if (err)
1644                 goto out;
1645
1646         flex_gd.count = 1;
1647         flex_gd.groups = input;
1648         flex_gd.bg_flags = &bg_flags;
1649         err = ext4_flex_group_add(sb, inode, &flex_gd);
1650 out:
1651         iput(inode);
1652         return err;
1653 } /* ext4_group_add */
1654
1655 /*
1656  * extend a group without checking assuming that checking has been done.
1657  */
1658 static int ext4_group_extend_no_check(struct super_block *sb,
1659                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1660 {
1661         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1662         handle_t *handle;
1663         int err = 0, err2;
1664
1665         /* We will update the superblock, one block bitmap, and
1666          * one group descriptor via ext4_group_add_blocks().
1667          */
1668         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1669         if (IS_ERR(handle)) {
1670                 err = PTR_ERR(handle);
1671                 ext4_warning(sb, "error %d on journal start", err);
1672                 return err;
1673         }
1674
1675         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1676         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1677         if (err) {
1678                 ext4_warning(sb, "error %d on journal write access", err);
1679                 goto errout;
1680         }
1681
1682         ext4_blocks_count_set(es, o_blocks_count + add);
1683         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1684         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1685                    o_blocks_count + add);
1686         /* We add the blocks to the bitmap and set the group need init bit */
1687         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1688         if (err)
1689                 goto errout;
1690         ext4_handle_dirty_super(handle, sb);
1691         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1692                    o_blocks_count + add);
1693 errout:
1694         err2 = ext4_journal_stop(handle);
1695         if (err2 && !err)
1696                 err = err2;
1697
1698         if (!err) {
1699                 if (test_opt(sb, DEBUG))
1700                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1701                                "blocks\n", ext4_blocks_count(es));
1702                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1703                                (char *)es, sizeof(struct ext4_super_block), 0);
1704         }
1705         return err;
1706 }
1707
1708 /*
1709  * Extend the filesystem to the new number of blocks specified.  This entry
1710  * point is only used to extend the current filesystem to the end of the last
1711  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1712  * for emergencies (because it has no dependencies on reserved blocks).
1713  *
1714  * If we _really_ wanted, we could use default values to call ext4_group_add()
1715  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1716  * GDT blocks are reserved to grow to the desired size.
1717  */
1718 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1719                       ext4_fsblk_t n_blocks_count)
1720 {
1721         ext4_fsblk_t o_blocks_count;
1722         ext4_grpblk_t last;
1723         ext4_grpblk_t add;
1724         struct buffer_head *bh;
1725         int err;
1726         ext4_group_t group;
1727
1728         o_blocks_count = ext4_blocks_count(es);
1729
1730         if (test_opt(sb, DEBUG))
1731                 ext4_msg(sb, KERN_DEBUG,
1732                          "extending last group from %llu to %llu blocks",
1733                          o_blocks_count, n_blocks_count);
1734
1735         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1736                 return 0;
1737
1738         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1739                 ext4_msg(sb, KERN_ERR,
1740                          "filesystem too large to resize to %llu blocks safely",
1741                          n_blocks_count);
1742                 return -EINVAL;
1743         }
1744
1745         if (n_blocks_count < o_blocks_count) {
1746                 ext4_warning(sb, "can't shrink FS - resize aborted");
1747                 return -EINVAL;
1748         }
1749
1750         /* Handle the remaining blocks in the last group only. */
1751         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1752
1753         if (last == 0) {
1754                 ext4_warning(sb, "need to use ext2online to resize further");
1755                 return -EPERM;
1756         }
1757
1758         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1759
1760         if (o_blocks_count + add < o_blocks_count) {
1761                 ext4_warning(sb, "blocks_count overflow");
1762                 return -EINVAL;
1763         }
1764
1765         if (o_blocks_count + add > n_blocks_count)
1766                 add = n_blocks_count - o_blocks_count;
1767
1768         if (o_blocks_count + add < n_blocks_count)
1769                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1770                              o_blocks_count + add, add);
1771
1772         /* See if the device is actually as big as what was requested */
1773         bh = sb_bread(sb, o_blocks_count + add - 1);
1774         if (!bh) {
1775                 ext4_warning(sb, "can't read last block, resize aborted");
1776                 return -ENOSPC;
1777         }
1778         brelse(bh);
1779
1780         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1781         return err;
1782 } /* ext4_group_extend */
1783
1784
1785 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1786 {
1787         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1788 }
1789
1790 /*
1791  * Release the resize inode and drop the resize_inode feature if there
1792  * are no more reserved gdt blocks, and then convert the file system
1793  * to enable meta_bg
1794  */
1795 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1796 {
1797         handle_t *handle;
1798         struct ext4_sb_info *sbi = EXT4_SB(sb);
1799         struct ext4_super_block *es = sbi->s_es;
1800         struct ext4_inode_info *ei = EXT4_I(inode);
1801         ext4_fsblk_t nr;
1802         int i, ret, err = 0;
1803         int credits = 1;
1804
1805         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1806         if (inode) {
1807                 if (es->s_reserved_gdt_blocks) {
1808                         ext4_error(sb, "Unexpected non-zero "
1809                                    "s_reserved_gdt_blocks");
1810                         return -EPERM;
1811                 }
1812
1813                 /* Do a quick sanity check of the resize inode */
1814                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1815                                              (9 - sbi->s_cluster_bits)))
1816                         goto invalid_resize_inode;
1817                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1818                         if (i == EXT4_DIND_BLOCK) {
1819                                 if (ei->i_data[i])
1820                                         continue;
1821                                 else
1822                                         goto invalid_resize_inode;
1823                         }
1824                         if (ei->i_data[i])
1825                                 goto invalid_resize_inode;
1826                 }
1827                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1828         }
1829
1830         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1831         if (IS_ERR(handle))
1832                 return PTR_ERR(handle);
1833
1834         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1835         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1836         if (err)
1837                 goto errout;
1838
1839         ext4_clear_feature_resize_inode(sb);
1840         ext4_set_feature_meta_bg(sb);
1841         sbi->s_es->s_first_meta_bg =
1842                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1843
1844         err = ext4_handle_dirty_super(handle, sb);
1845         if (err) {
1846                 ext4_std_error(sb, err);
1847                 goto errout;
1848         }
1849
1850         if (inode) {
1851                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1852                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1853                                  EXT4_FREE_BLOCKS_METADATA |
1854                                  EXT4_FREE_BLOCKS_FORGET);
1855                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1856                 inode->i_blocks = 0;
1857
1858                 err = ext4_mark_inode_dirty(handle, inode);
1859                 if (err)
1860                         ext4_std_error(sb, err);
1861         }
1862
1863 errout:
1864         ret = ext4_journal_stop(handle);
1865         if (!err)
1866                 err = ret;
1867         return ret;
1868
1869 invalid_resize_inode:
1870         ext4_error(sb, "corrupted/inconsistent resize inode");
1871         return -EINVAL;
1872 }
1873
1874 /*
1875  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1876  *
1877  * @sb: super block of the fs to be resized
1878  * @n_blocks_count: the number of blocks resides in the resized fs
1879  */
1880 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1881 {
1882         struct ext4_new_flex_group_data *flex_gd = NULL;
1883         struct ext4_sb_info *sbi = EXT4_SB(sb);
1884         struct ext4_super_block *es = sbi->s_es;
1885         struct buffer_head *bh;
1886         struct inode *resize_inode = NULL;
1887         ext4_grpblk_t add, offset;
1888         unsigned long n_desc_blocks;
1889         unsigned long o_desc_blocks;
1890         ext4_group_t o_group;
1891         ext4_group_t n_group;
1892         ext4_fsblk_t o_blocks_count;
1893         ext4_fsblk_t n_blocks_count_retry = 0;
1894         unsigned long last_update_time = 0;
1895         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1896         int meta_bg;
1897
1898         /* See if the device is actually as big as what was requested */
1899         bh = sb_bread(sb, n_blocks_count - 1);
1900         if (!bh) {
1901                 ext4_warning(sb, "can't read last block, resize aborted");
1902                 return -ENOSPC;
1903         }
1904         brelse(bh);
1905
1906 retry:
1907         o_blocks_count = ext4_blocks_count(es);
1908
1909         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1910                  "to %llu blocks", o_blocks_count, n_blocks_count);
1911
1912         if (n_blocks_count < o_blocks_count) {
1913                 /* On-line shrinking not supported */
1914                 ext4_warning(sb, "can't shrink FS - resize aborted");
1915                 return -EINVAL;
1916         }
1917
1918         if (n_blocks_count == o_blocks_count)
1919                 /* Nothing need to do */
1920                 return 0;
1921
1922         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1923         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1924                 ext4_warning(sb, "resize would cause inodes_count overflow");
1925                 return -EINVAL;
1926         }
1927         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1928
1929         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1930         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1931
1932         meta_bg = ext4_has_feature_meta_bg(sb);
1933
1934         if (ext4_has_feature_resize_inode(sb)) {
1935                 if (meta_bg) {
1936                         ext4_error(sb, "resize_inode and meta_bg enabled "
1937                                    "simultaneously");
1938                         return -EINVAL;
1939                 }
1940                 if (n_desc_blocks > o_desc_blocks +
1941                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1942                         n_blocks_count_retry = n_blocks_count;
1943                         n_desc_blocks = o_desc_blocks +
1944                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1945                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1946                         n_blocks_count = (ext4_fsblk_t)n_group *
1947                                 EXT4_BLOCKS_PER_GROUP(sb) +
1948                                 le32_to_cpu(es->s_first_data_block);
1949                         n_group--; /* set to last group number */
1950                 }
1951
1952                 if (!resize_inode)
1953                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
1954                                                  EXT4_IGET_SPECIAL);
1955                 if (IS_ERR(resize_inode)) {
1956                         ext4_warning(sb, "Error opening resize inode");
1957                         return PTR_ERR(resize_inode);
1958                 }
1959         }
1960
1961         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1962                 err = ext4_convert_meta_bg(sb, resize_inode);
1963                 if (err)
1964                         goto out;
1965                 if (resize_inode) {
1966                         iput(resize_inode);
1967                         resize_inode = NULL;
1968                 }
1969                 if (n_blocks_count_retry) {
1970                         n_blocks_count = n_blocks_count_retry;
1971                         n_blocks_count_retry = 0;
1972                         goto retry;
1973                 }
1974         }
1975
1976         /*
1977          * Make sure the last group has enough space so that it's
1978          * guaranteed to have enough space for all metadata blocks
1979          * that it might need to hold.  (We might not need to store
1980          * the inode table blocks in the last block group, but there
1981          * will be cases where this might be needed.)
1982          */
1983         if ((ext4_group_first_block_no(sb, n_group) +
1984              ext4_group_overhead_blocks(sb, n_group) + 2 +
1985              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
1986                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
1987                 n_group--;
1988                 n_blocks_count_retry = 0;
1989                 if (resize_inode) {
1990                         iput(resize_inode);
1991                         resize_inode = NULL;
1992                 }
1993                 goto retry;
1994         }
1995
1996         /* extend the last group */
1997         if (n_group == o_group)
1998                 add = n_blocks_count - o_blocks_count;
1999         else
2000                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2001         if (add > 0) {
2002                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2003                 if (err)
2004                         goto out;
2005         }
2006
2007         if (ext4_blocks_count(es) == n_blocks_count)
2008                 goto out;
2009
2010         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2011         if (err)
2012                 goto out;
2013
2014         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2015         if (err)
2016                 goto out;
2017
2018         flex_gd = alloc_flex_gd(flexbg_size);
2019         if (flex_gd == NULL) {
2020                 err = -ENOMEM;
2021                 goto out;
2022         }
2023
2024         /* Add flex groups. Note that a regular group is a
2025          * flex group with 1 group.
2026          */
2027         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2028                                               flexbg_size)) {
2029                 if (jiffies - last_update_time > HZ * 10) {
2030                         if (last_update_time)
2031                                 ext4_msg(sb, KERN_INFO,
2032                                          "resized to %llu blocks",
2033                                          ext4_blocks_count(es));
2034                         last_update_time = jiffies;
2035                 }
2036                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2037                         break;
2038                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2039                 if (unlikely(err))
2040                         break;
2041         }
2042
2043         if (!err && n_blocks_count_retry) {
2044                 n_blocks_count = n_blocks_count_retry;
2045                 n_blocks_count_retry = 0;
2046                 free_flex_gd(flex_gd);
2047                 flex_gd = NULL;
2048                 if (resize_inode) {
2049                         iput(resize_inode);
2050                         resize_inode = NULL;
2051                 }
2052                 goto retry;
2053         }
2054
2055 out:
2056         if (flex_gd)
2057                 free_flex_gd(flex_gd);
2058         if (resize_inode != NULL)
2059                 iput(resize_inode);
2060         if (err)
2061                 ext4_warning(sb, "error (%d) occurred during "
2062                              "file system resize", err);
2063         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2064                  ext4_blocks_count(es));
2065         return err;
2066 }