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