linux/fs/ext4/resize.c
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   1/*
   2 *  linux/fs/ext4/resize.c
   3 *
   4 * Support for resizing an ext4 filesystem while it is mounted.
   5 *
   6 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   7 *
   8 * This could probably be made into a module, because it is not often in use.
   9 */
  10
  11
  12#define EXT4FS_DEBUG
  13
  14#include <linux/errno.h>
  15#include <linux/slab.h>
  16
  17#include "ext4_jbd2.h"
  18
  19int ext4_resize_begin(struct super_block *sb)
  20{
  21        int ret = 0;
  22
  23        if (!capable(CAP_SYS_RESOURCE))
  24                return -EPERM;
  25
  26        /*
  27         * We are not allowed to do online-resizing on a filesystem mounted
  28         * with error, because it can destroy the filesystem easily.
  29         */
  30        if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  31                ext4_warning(sb, "There are errors in the filesystem, "
  32                             "so online resizing is not allowed\n");
  33                return -EPERM;
  34        }
  35
  36        if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
  37                ret = -EBUSY;
  38
  39        return ret;
  40}
  41
  42void ext4_resize_end(struct super_block *sb)
  43{
  44        clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
  45        smp_mb__after_clear_bit();
  46}
  47
  48static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  49                                             ext4_group_t group) {
  50        return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  51               EXT4_DESC_PER_BLOCK_BITS(sb);
  52}
  53
  54static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  55                                             ext4_group_t group) {
  56        group = ext4_meta_bg_first_group(sb, group);
  57        return ext4_group_first_block_no(sb, group);
  58}
  59
  60static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  61                                                ext4_group_t group) {
  62        ext4_grpblk_t overhead;
  63        overhead = ext4_bg_num_gdb(sb, group);
  64        if (ext4_bg_has_super(sb, group))
  65                overhead += 1 +
  66                          le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  67        return overhead;
  68}
  69
  70#define outside(b, first, last) ((b) < (first) || (b) >= (last))
  71#define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  72
  73static int verify_group_input(struct super_block *sb,
  74                              struct ext4_new_group_data *input)
  75{
  76        struct ext4_sb_info *sbi = EXT4_SB(sb);
  77        struct ext4_super_block *es = sbi->s_es;
  78        ext4_fsblk_t start = ext4_blocks_count(es);
  79        ext4_fsblk_t end = start + input->blocks_count;
  80        ext4_group_t group = input->group;
  81        ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  82        unsigned overhead = ext4_group_overhead_blocks(sb, group);
  83        ext4_fsblk_t metaend = start + overhead;
  84        struct buffer_head *bh = NULL;
  85        ext4_grpblk_t free_blocks_count, offset;
  86        int err = -EINVAL;
  87
  88        input->free_blocks_count = free_blocks_count =
  89                input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
  90
  91        if (test_opt(sb, DEBUG))
  92                printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
  93                       "(%d free, %u reserved)\n",
  94                       ext4_bg_has_super(sb, input->group) ? "normal" :
  95                       "no-super", input->group, input->blocks_count,
  96                       free_blocks_count, input->reserved_blocks);
  97
  98        ext4_get_group_no_and_offset(sb, start, NULL, &offset);
  99        if (group != sbi->s_groups_count)
 100                ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 101                             input->group, sbi->s_groups_count);
 102        else if (offset != 0)
 103                        ext4_warning(sb, "Last group not full");
 104        else if (input->reserved_blocks > input->blocks_count / 5)
 105                ext4_warning(sb, "Reserved blocks too high (%u)",
 106                             input->reserved_blocks);
 107        else if (free_blocks_count < 0)
 108                ext4_warning(sb, "Bad blocks count %u",
 109                             input->blocks_count);
 110        else if (!(bh = sb_bread(sb, end - 1)))
 111                ext4_warning(sb, "Cannot read last block (%llu)",
 112                             end - 1);
 113        else if (outside(input->block_bitmap, start, end))
 114                ext4_warning(sb, "Block bitmap not in group (block %llu)",
 115                             (unsigned long long)input->block_bitmap);
 116        else if (outside(input->inode_bitmap, start, end))
 117                ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 118                             (unsigned long long)input->inode_bitmap);
 119        else if (outside(input->inode_table, start, end) ||
 120                 outside(itend - 1, start, end))
 121                ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 122                             (unsigned long long)input->inode_table, itend - 1);
 123        else if (input->inode_bitmap == input->block_bitmap)
 124                ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 125                             (unsigned long long)input->block_bitmap);
 126        else if (inside(input->block_bitmap, input->inode_table, itend))
 127                ext4_warning(sb, "Block bitmap (%llu) in inode table "
 128                             "(%llu-%llu)",
 129                             (unsigned long long)input->block_bitmap,
 130                             (unsigned long long)input->inode_table, itend - 1);
 131        else if (inside(input->inode_bitmap, input->inode_table, itend))
 132                ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 133                             "(%llu-%llu)",
 134                             (unsigned long long)input->inode_bitmap,
 135                             (unsigned long long)input->inode_table, itend - 1);
 136        else if (inside(input->block_bitmap, start, metaend))
 137                ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 138                             (unsigned long long)input->block_bitmap,
 139                             start, metaend - 1);
 140        else if (inside(input->inode_bitmap, start, metaend))
 141                ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 142                             (unsigned long long)input->inode_bitmap,
 143                             start, metaend - 1);
 144        else if (inside(input->inode_table, start, metaend) ||
 145                 inside(itend - 1, start, metaend))
 146                ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 147                             "(%llu-%llu)",
 148                             (unsigned long long)input->inode_table,
 149                             itend - 1, start, metaend - 1);
 150        else
 151                err = 0;
 152        brelse(bh);
 153
 154        return err;
 155}
 156
 157/*
 158 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 159 * group each time.
 160 */
 161struct ext4_new_flex_group_data {
 162        struct ext4_new_group_data *groups;     /* new_group_data for groups
 163                                                   in the flex group */
 164        __u16 *bg_flags;                        /* block group flags of groups
 165                                                   in @groups */
 166        ext4_group_t count;                     /* number of groups in @groups
 167                                                 */
 168};
 169
 170/*
 171 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 172 * @flexbg_size.
 173 *
 174 * Returns NULL on failure otherwise address of the allocated structure.
 175 */
 176static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 177{
 178        struct ext4_new_flex_group_data *flex_gd;
 179
 180        flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 181        if (flex_gd == NULL)
 182                goto out3;
 183
 184        if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
 185                goto out2;
 186        flex_gd->count = flexbg_size;
 187
 188        flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 189                                  flexbg_size, GFP_NOFS);
 190        if (flex_gd->groups == NULL)
 191                goto out2;
 192
 193        flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 194        if (flex_gd->bg_flags == NULL)
 195                goto out1;
 196
 197        return flex_gd;
 198
 199out1:
 200        kfree(flex_gd->groups);
 201out2:
 202        kfree(flex_gd);
 203out3:
 204        return NULL;
 205}
 206
 207static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 208{
 209        kfree(flex_gd->bg_flags);
 210        kfree(flex_gd->groups);
 211        kfree(flex_gd);
 212}
 213
 214/*
 215 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 216 * and inode tables for a flex group.
 217 *
 218 * This function is used by 64bit-resize.  Note that this function allocates
 219 * group tables from the 1st group of groups contained by @flexgd, which may
 220 * be a partial of a flex group.
 221 *
 222 * @sb: super block of fs to which the groups belongs
 223 *
 224 * Returns 0 on a successful allocation of the metadata blocks in the
 225 * block group.
 226 */
 227static int ext4_alloc_group_tables(struct super_block *sb,
 228                                struct ext4_new_flex_group_data *flex_gd,
 229                                int flexbg_size)
 230{
 231        struct ext4_new_group_data *group_data = flex_gd->groups;
 232        ext4_fsblk_t start_blk;
 233        ext4_fsblk_t last_blk;
 234        ext4_group_t src_group;
 235        ext4_group_t bb_index = 0;
 236        ext4_group_t ib_index = 0;
 237        ext4_group_t it_index = 0;
 238        ext4_group_t group;
 239        ext4_group_t last_group;
 240        unsigned overhead;
 241
 242        BUG_ON(flex_gd->count == 0 || group_data == NULL);
 243
 244        src_group = group_data[0].group;
 245        last_group  = src_group + flex_gd->count - 1;
 246
 247        BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 248               (last_group & ~(flexbg_size - 1))));
 249next_group:
 250        group = group_data[0].group;
 251        if (src_group >= group_data[0].group + flex_gd->count)
 252                return -ENOSPC;
 253        start_blk = ext4_group_first_block_no(sb, src_group);
 254        last_blk = start_blk + group_data[src_group - group].blocks_count;
 255
 256        overhead = ext4_group_overhead_blocks(sb, src_group);
 257
 258        start_blk += overhead;
 259
 260        /* We collect contiguous blocks as much as possible. */
 261        src_group++;
 262        for (; src_group <= last_group; src_group++) {
 263                overhead = ext4_group_overhead_blocks(sb, src_group);
 264                if (overhead != 0)
 265                        last_blk += group_data[src_group - group].blocks_count;
 266                else
 267                        break;
 268        }
 269
 270        /* Allocate block bitmaps */
 271        for (; bb_index < flex_gd->count; bb_index++) {
 272                if (start_blk >= last_blk)
 273                        goto next_group;
 274                group_data[bb_index].block_bitmap = start_blk++;
 275                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 276                group -= group_data[0].group;
 277                group_data[group].free_blocks_count--;
 278                if (flexbg_size > 1)
 279                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 280        }
 281
 282        /* Allocate inode bitmaps */
 283        for (; ib_index < flex_gd->count; ib_index++) {
 284                if (start_blk >= last_blk)
 285                        goto next_group;
 286                group_data[ib_index].inode_bitmap = start_blk++;
 287                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 288                group -= group_data[0].group;
 289                group_data[group].free_blocks_count--;
 290                if (flexbg_size > 1)
 291                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 292        }
 293
 294        /* Allocate inode tables */
 295        for (; it_index < flex_gd->count; it_index++) {
 296                if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
 297                        goto next_group;
 298                group_data[it_index].inode_table = start_blk;
 299                ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
 300                group -= group_data[0].group;
 301                group_data[group].free_blocks_count -=
 302                                        EXT4_SB(sb)->s_itb_per_group;
 303                if (flexbg_size > 1)
 304                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 305
 306                start_blk += EXT4_SB(sb)->s_itb_per_group;
 307        }
 308
 309        if (test_opt(sb, DEBUG)) {
 310                int i;
 311                group = group_data[0].group;
 312
 313                printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 314                       "%d groups, flexbg size is %d:\n", flex_gd->count,
 315                       flexbg_size);
 316
 317                for (i = 0; i < flex_gd->count; i++) {
 318                        printk(KERN_DEBUG "adding %s group %u: %u "
 319                               "blocks (%d free)\n",
 320                               ext4_bg_has_super(sb, group + i) ? "normal" :
 321                               "no-super", group + i,
 322                               group_data[i].blocks_count,
 323                               group_data[i].free_blocks_count);
 324                }
 325        }
 326        return 0;
 327}
 328
 329static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 330                                  ext4_fsblk_t blk)
 331{
 332        struct buffer_head *bh;
 333        int err;
 334
 335        bh = sb_getblk(sb, blk);
 336        if (!bh)
 337                return ERR_PTR(-EIO);
 338        if ((err = ext4_journal_get_write_access(handle, bh))) {
 339                brelse(bh);
 340                bh = ERR_PTR(err);
 341        } else {
 342                memset(bh->b_data, 0, sb->s_blocksize);
 343                set_buffer_uptodate(bh);
 344        }
 345
 346        return bh;
 347}
 348
 349/*
 350 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 351 * If that fails, restart the transaction & regain write access for the
 352 * buffer head which is used for block_bitmap modifications.
 353 */
 354static int extend_or_restart_transaction(handle_t *handle, int thresh)
 355{
 356        int err;
 357
 358        if (ext4_handle_has_enough_credits(handle, thresh))
 359                return 0;
 360
 361        err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 362        if (err < 0)
 363                return err;
 364        if (err) {
 365                err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 366                if (err)
 367                        return err;
 368        }
 369
 370        return 0;
 371}
 372
 373/*
 374 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 375 *
 376 * Helper function for ext4_setup_new_group_blocks() which set .
 377 *
 378 * @sb: super block
 379 * @handle: journal handle
 380 * @flex_gd: flex group data
 381 */
 382static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 383                        struct ext4_new_flex_group_data *flex_gd,
 384                        ext4_fsblk_t block, ext4_group_t count)
 385{
 386        ext4_group_t count2;
 387
 388        ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 389        for (count2 = count; count > 0; count -= count2, block += count2) {
 390                ext4_fsblk_t start;
 391                struct buffer_head *bh;
 392                ext4_group_t group;
 393                int err;
 394
 395                ext4_get_group_no_and_offset(sb, block, &group, NULL);
 396                start = ext4_group_first_block_no(sb, group);
 397                group -= flex_gd->groups[0].group;
 398
 399                count2 = sb->s_blocksize * 8 - (block - start);
 400                if (count2 > count)
 401                        count2 = count;
 402
 403                if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 404                        BUG_ON(flex_gd->count > 1);
 405                        continue;
 406                }
 407
 408                err = extend_or_restart_transaction(handle, 1);
 409                if (err)
 410                        return err;
 411
 412                bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 413                if (!bh)
 414                        return -EIO;
 415
 416                err = ext4_journal_get_write_access(handle, bh);
 417                if (err)
 418                        return err;
 419                ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 420                           block - start, count2);
 421                ext4_set_bits(bh->b_data, block - start, count2);
 422
 423                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 424                if (unlikely(err))
 425                        return err;
 426                brelse(bh);
 427        }
 428
 429        return 0;
 430}
 431
 432/*
 433 * Set up the block and inode bitmaps, and the inode table for the new groups.
 434 * This doesn't need to be part of the main transaction, since we are only
 435 * changing blocks outside the actual filesystem.  We still do journaling to
 436 * ensure the recovery is correct in case of a failure just after resize.
 437 * If any part of this fails, we simply abort the resize.
 438 *
 439 * setup_new_flex_group_blocks handles a flex group as follow:
 440 *  1. copy super block and GDT, and initialize group tables if necessary.
 441 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 442 *     super block and GDT.
 443 *  2. allocate group tables in block bitmaps, that is, set bits in block
 444 *     bitmap for blocks taken by group tables.
 445 */
 446static int setup_new_flex_group_blocks(struct super_block *sb,
 447                                struct ext4_new_flex_group_data *flex_gd)
 448{
 449        int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 450        ext4_fsblk_t start;
 451        ext4_fsblk_t block;
 452        struct ext4_sb_info *sbi = EXT4_SB(sb);
 453        struct ext4_super_block *es = sbi->s_es;
 454        struct ext4_new_group_data *group_data = flex_gd->groups;
 455        __u16 *bg_flags = flex_gd->bg_flags;
 456        handle_t *handle;
 457        ext4_group_t group, count;
 458        struct buffer_head *bh = NULL;
 459        int reserved_gdb, i, j, err = 0, err2;
 460        int meta_bg;
 461
 462        BUG_ON(!flex_gd->count || !group_data ||
 463               group_data[0].group != sbi->s_groups_count);
 464
 465        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 466        meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
 467
 468        /* This transaction may be extended/restarted along the way */
 469        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 470        if (IS_ERR(handle))
 471                return PTR_ERR(handle);
 472
 473        group = group_data[0].group;
 474        for (i = 0; i < flex_gd->count; i++, group++) {
 475                unsigned long gdblocks;
 476                ext4_grpblk_t overhead;
 477
 478                gdblocks = ext4_bg_num_gdb(sb, group);
 479                start = ext4_group_first_block_no(sb, group);
 480
 481                if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 482                        goto handle_itb;
 483
 484                if (meta_bg == 1) {
 485                        ext4_group_t first_group;
 486                        first_group = ext4_meta_bg_first_group(sb, group);
 487                        if (first_group != group + 1 &&
 488                            first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 489                                goto handle_itb;
 490                }
 491
 492                block = start + ext4_bg_has_super(sb, group);
 493                /* Copy all of the GDT blocks into the backup in this group */
 494                for (j = 0; j < gdblocks; j++, block++) {
 495                        struct buffer_head *gdb;
 496
 497                        ext4_debug("update backup group %#04llx\n", block);
 498                        err = extend_or_restart_transaction(handle, 1);
 499                        if (err)
 500                                goto out;
 501
 502                        gdb = sb_getblk(sb, block);
 503                        if (!gdb) {
 504                                err = -EIO;
 505                                goto out;
 506                        }
 507
 508                        err = ext4_journal_get_write_access(handle, gdb);
 509                        if (err) {
 510                                brelse(gdb);
 511                                goto out;
 512                        }
 513                        memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 514                               gdb->b_size);
 515                        set_buffer_uptodate(gdb);
 516
 517                        err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 518                        if (unlikely(err)) {
 519                                brelse(gdb);
 520                                goto out;
 521                        }
 522                        brelse(gdb);
 523                }
 524
 525                /* Zero out all of the reserved backup group descriptor
 526                 * table blocks
 527                 */
 528                if (ext4_bg_has_super(sb, group)) {
 529                        err = sb_issue_zeroout(sb, gdblocks + start + 1,
 530                                        reserved_gdb, GFP_NOFS);
 531                        if (err)
 532                                goto out;
 533                }
 534
 535handle_itb:
 536                /* Initialize group tables of the grop @group */
 537                if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 538                        goto handle_bb;
 539
 540                /* Zero out all of the inode table blocks */
 541                block = group_data[i].inode_table;
 542                ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 543                           block, sbi->s_itb_per_group);
 544                err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 545                                       GFP_NOFS);
 546                if (err)
 547                        goto out;
 548
 549handle_bb:
 550                if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 551                        goto handle_ib;
 552
 553                /* Initialize block bitmap of the @group */
 554                block = group_data[i].block_bitmap;
 555                err = extend_or_restart_transaction(handle, 1);
 556                if (err)
 557                        goto out;
 558
 559                bh = bclean(handle, sb, block);
 560                if (IS_ERR(bh)) {
 561                        err = PTR_ERR(bh);
 562                        goto out;
 563                }
 564                overhead = ext4_group_overhead_blocks(sb, group);
 565                if (overhead != 0) {
 566                        ext4_debug("mark backup superblock %#04llx (+0)\n",
 567                                   start);
 568                        ext4_set_bits(bh->b_data, 0, overhead);
 569                }
 570                ext4_mark_bitmap_end(group_data[i].blocks_count,
 571                                     sb->s_blocksize * 8, bh->b_data);
 572                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 573                if (err)
 574                        goto out;
 575                brelse(bh);
 576
 577handle_ib:
 578                if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 579                        continue;
 580
 581                /* Initialize inode bitmap of the @group */
 582                block = group_data[i].inode_bitmap;
 583                err = extend_or_restart_transaction(handle, 1);
 584                if (err)
 585                        goto out;
 586                /* Mark unused entries in inode bitmap used */
 587                bh = bclean(handle, sb, block);
 588                if (IS_ERR(bh)) {
 589                        err = PTR_ERR(bh);
 590                        goto out;
 591                }
 592
 593                ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 594                                     sb->s_blocksize * 8, bh->b_data);
 595                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 596                if (err)
 597                        goto out;
 598                brelse(bh);
 599        }
 600        bh = NULL;
 601
 602        /* Mark group tables in block bitmap */
 603        for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 604                count = group_table_count[j];
 605                start = (&group_data[0].block_bitmap)[j];
 606                block = start;
 607                for (i = 1; i < flex_gd->count; i++) {
 608                        block += group_table_count[j];
 609                        if (block == (&group_data[i].block_bitmap)[j]) {
 610                                count += group_table_count[j];
 611                                continue;
 612                        }
 613                        err = set_flexbg_block_bitmap(sb, handle,
 614                                                flex_gd, start, count);
 615                        if (err)
 616                                goto out;
 617                        count = group_table_count[j];
 618                        start = group_data[i].block_bitmap;
 619                        block = start;
 620                }
 621
 622                if (count) {
 623                        err = set_flexbg_block_bitmap(sb, handle,
 624                                                flex_gd, start, count);
 625                        if (err)
 626                                goto out;
 627                }
 628        }
 629
 630out:
 631        brelse(bh);
 632        err2 = ext4_journal_stop(handle);
 633        if (err2 && !err)
 634                err = err2;
 635
 636        return err;
 637}
 638
 639/*
 640 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 641 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 642 * calling this for the first time.  In a sparse filesystem it will be the
 643 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 644 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 645 */
 646static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 647                                  unsigned *five, unsigned *seven)
 648{
 649        unsigned *min = three;
 650        int mult = 3;
 651        unsigned ret;
 652
 653        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 654                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 655                ret = *min;
 656                *min += 1;
 657                return ret;
 658        }
 659
 660        if (*five < *min) {
 661                min = five;
 662                mult = 5;
 663        }
 664        if (*seven < *min) {
 665                min = seven;
 666                mult = 7;
 667        }
 668
 669        ret = *min;
 670        *min *= mult;
 671
 672        return ret;
 673}
 674
 675/*
 676 * Check that all of the backup GDT blocks are held in the primary GDT block.
 677 * It is assumed that they are stored in group order.  Returns the number of
 678 * groups in current filesystem that have BACKUPS, or -ve error code.
 679 */
 680static int verify_reserved_gdb(struct super_block *sb,
 681                               ext4_group_t end,
 682                               struct buffer_head *primary)
 683{
 684        const ext4_fsblk_t blk = primary->b_blocknr;
 685        unsigned three = 1;
 686        unsigned five = 5;
 687        unsigned seven = 7;
 688        unsigned grp;
 689        __le32 *p = (__le32 *)primary->b_data;
 690        int gdbackups = 0;
 691
 692        while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 693                if (le32_to_cpu(*p++) !=
 694                    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 695                        ext4_warning(sb, "reserved GDT %llu"
 696                                     " missing grp %d (%llu)",
 697                                     blk, grp,
 698                                     grp *
 699                                     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 700                                     blk);
 701                        return -EINVAL;
 702                }
 703                if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 704                        return -EFBIG;
 705        }
 706
 707        return gdbackups;
 708}
 709
 710/*
 711 * Called when we need to bring a reserved group descriptor table block into
 712 * use from the resize inode.  The primary copy of the new GDT block currently
 713 * is an indirect block (under the double indirect block in the resize inode).
 714 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 715 * block, in group order.  Even though we know all the block numbers we need,
 716 * we check to ensure that the resize inode has actually reserved these blocks.
 717 *
 718 * Don't need to update the block bitmaps because the blocks are still in use.
 719 *
 720 * We get all of the error cases out of the way, so that we are sure to not
 721 * fail once we start modifying the data on disk, because JBD has no rollback.
 722 */
 723static int add_new_gdb(handle_t *handle, struct inode *inode,
 724                       ext4_group_t group)
 725{
 726        struct super_block *sb = inode->i_sb;
 727        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 728        unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 729        ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 730        struct buffer_head **o_group_desc, **n_group_desc;
 731        struct buffer_head *dind;
 732        struct buffer_head *gdb_bh;
 733        int gdbackups;
 734        struct ext4_iloc iloc;
 735        __le32 *data;
 736        int err;
 737
 738        if (test_opt(sb, DEBUG))
 739                printk(KERN_DEBUG
 740                       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 741                       gdb_num);
 742
 743        /*
 744         * If we are not using the primary superblock/GDT copy don't resize,
 745         * because the user tools have no way of handling this.  Probably a
 746         * bad time to do it anyways.
 747         */
 748        if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 749            le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 750                ext4_warning(sb, "won't resize using backup superblock at %llu",
 751                        (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 752                return -EPERM;
 753        }
 754
 755        gdb_bh = sb_bread(sb, gdblock);
 756        if (!gdb_bh)
 757                return -EIO;
 758
 759        gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 760        if (gdbackups < 0) {
 761                err = gdbackups;
 762                goto exit_bh;
 763        }
 764
 765        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 766        dind = sb_bread(sb, le32_to_cpu(*data));
 767        if (!dind) {
 768                err = -EIO;
 769                goto exit_bh;
 770        }
 771
 772        data = (__le32 *)dind->b_data;
 773        if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 774                ext4_warning(sb, "new group %u GDT block %llu not reserved",
 775                             group, gdblock);
 776                err = -EINVAL;
 777                goto exit_dind;
 778        }
 779
 780        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 781        if (unlikely(err))
 782                goto exit_dind;
 783
 784        err = ext4_journal_get_write_access(handle, gdb_bh);
 785        if (unlikely(err))
 786                goto exit_sbh;
 787
 788        err = ext4_journal_get_write_access(handle, dind);
 789        if (unlikely(err))
 790                ext4_std_error(sb, err);
 791
 792        /* ext4_reserve_inode_write() gets a reference on the iloc */
 793        err = ext4_reserve_inode_write(handle, inode, &iloc);
 794        if (unlikely(err))
 795                goto exit_dindj;
 796
 797        n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 798                                     sizeof(struct buffer_head *),
 799                                     GFP_NOFS);
 800        if (!n_group_desc) {
 801                err = -ENOMEM;
 802                ext4_warning(sb, "not enough memory for %lu groups",
 803                             gdb_num + 1);
 804                goto exit_inode;
 805        }
 806
 807        /*
 808         * Finally, we have all of the possible failures behind us...
 809         *
 810         * Remove new GDT block from inode double-indirect block and clear out
 811         * the new GDT block for use (which also "frees" the backup GDT blocks
 812         * from the reserved inode).  We don't need to change the bitmaps for
 813         * these blocks, because they are marked as in-use from being in the
 814         * reserved inode, and will become GDT blocks (primary and backup).
 815         */
 816        data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 817        err = ext4_handle_dirty_metadata(handle, NULL, dind);
 818        if (unlikely(err)) {
 819                ext4_std_error(sb, err);
 820                goto exit_inode;
 821        }
 822        inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 823        ext4_mark_iloc_dirty(handle, inode, &iloc);
 824        memset(gdb_bh->b_data, 0, sb->s_blocksize);
 825        err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 826        if (unlikely(err)) {
 827                ext4_std_error(sb, err);
 828                goto exit_inode;
 829        }
 830        brelse(dind);
 831
 832        o_group_desc = EXT4_SB(sb)->s_group_desc;
 833        memcpy(n_group_desc, o_group_desc,
 834               EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 835        n_group_desc[gdb_num] = gdb_bh;
 836        EXT4_SB(sb)->s_group_desc = n_group_desc;
 837        EXT4_SB(sb)->s_gdb_count++;
 838        ext4_kvfree(o_group_desc);
 839
 840        le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 841        err = ext4_handle_dirty_super(handle, sb);
 842        if (err)
 843                ext4_std_error(sb, err);
 844
 845        return err;
 846
 847exit_inode:
 848        ext4_kvfree(n_group_desc);
 849        /* ext4_handle_release_buffer(handle, iloc.bh); */
 850        brelse(iloc.bh);
 851exit_dindj:
 852        /* ext4_handle_release_buffer(handle, dind); */
 853exit_sbh:
 854        /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
 855exit_dind:
 856        brelse(dind);
 857exit_bh:
 858        brelse(gdb_bh);
 859
 860        ext4_debug("leaving with error %d\n", err);
 861        return err;
 862}
 863
 864/*
 865 * add_new_gdb_meta_bg is the sister of add_new_gdb.
 866 */
 867static int add_new_gdb_meta_bg(struct super_block *sb,
 868                               handle_t *handle, ext4_group_t group) {
 869        ext4_fsblk_t gdblock;
 870        struct buffer_head *gdb_bh;
 871        struct buffer_head **o_group_desc, **n_group_desc;
 872        unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 873        int err;
 874
 875        gdblock = ext4_meta_bg_first_block_no(sb, group) +
 876                   ext4_bg_has_super(sb, group);
 877        gdb_bh = sb_bread(sb, gdblock);
 878        if (!gdb_bh)
 879                return -EIO;
 880        n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 881                                     sizeof(struct buffer_head *),
 882                                     GFP_NOFS);
 883        if (!n_group_desc) {
 884                err = -ENOMEM;
 885                ext4_warning(sb, "not enough memory for %lu groups",
 886                             gdb_num + 1);
 887                return err;
 888        }
 889
 890        o_group_desc = EXT4_SB(sb)->s_group_desc;
 891        memcpy(n_group_desc, o_group_desc,
 892               EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 893        n_group_desc[gdb_num] = gdb_bh;
 894        EXT4_SB(sb)->s_group_desc = n_group_desc;
 895        EXT4_SB(sb)->s_gdb_count++;
 896        ext4_kvfree(o_group_desc);
 897        err = ext4_journal_get_write_access(handle, gdb_bh);
 898        if (unlikely(err))
 899                brelse(gdb_bh);
 900        return err;
 901}
 902
 903/*
 904 * Called when we are adding a new group which has a backup copy of each of
 905 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 906 * We need to add these reserved backup GDT blocks to the resize inode, so
 907 * that they are kept for future resizing and not allocated to files.
 908 *
 909 * Each reserved backup GDT block will go into a different indirect block.
 910 * The indirect blocks are actually the primary reserved GDT blocks,
 911 * so we know in advance what their block numbers are.  We only get the
 912 * double-indirect block to verify it is pointing to the primary reserved
 913 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 914 * backup GDT blocks are stored in their reserved primary GDT block.
 915 */
 916static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 917                              ext4_group_t group)
 918{
 919        struct super_block *sb = inode->i_sb;
 920        int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 921        struct buffer_head **primary;
 922        struct buffer_head *dind;
 923        struct ext4_iloc iloc;
 924        ext4_fsblk_t blk;
 925        __le32 *data, *end;
 926        int gdbackups = 0;
 927        int res, i;
 928        int err;
 929
 930        primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 931        if (!primary)
 932                return -ENOMEM;
 933
 934        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 935        dind = sb_bread(sb, le32_to_cpu(*data));
 936        if (!dind) {
 937                err = -EIO;
 938                goto exit_free;
 939        }
 940
 941        blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 942        data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 943                                         EXT4_ADDR_PER_BLOCK(sb));
 944        end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 945
 946        /* Get each reserved primary GDT block and verify it holds backups */
 947        for (res = 0; res < reserved_gdb; res++, blk++) {
 948                if (le32_to_cpu(*data) != blk) {
 949                        ext4_warning(sb, "reserved block %llu"
 950                                     " not at offset %ld",
 951                                     blk,
 952                                     (long)(data - (__le32 *)dind->b_data));
 953                        err = -EINVAL;
 954                        goto exit_bh;
 955                }
 956                primary[res] = sb_bread(sb, blk);
 957                if (!primary[res]) {
 958                        err = -EIO;
 959                        goto exit_bh;
 960                }
 961                gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 962                if (gdbackups < 0) {
 963                        brelse(primary[res]);
 964                        err = gdbackups;
 965                        goto exit_bh;
 966                }
 967                if (++data >= end)
 968                        data = (__le32 *)dind->b_data;
 969        }
 970
 971        for (i = 0; i < reserved_gdb; i++) {
 972                if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
 973                        /*
 974                        int j;
 975                        for (j = 0; j < i; j++)
 976                                ext4_handle_release_buffer(handle, primary[j]);
 977                         */
 978                        goto exit_bh;
 979                }
 980        }
 981
 982        if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 983                goto exit_bh;
 984
 985        /*
 986         * Finally we can add each of the reserved backup GDT blocks from
 987         * the new group to its reserved primary GDT block.
 988         */
 989        blk = group * EXT4_BLOCKS_PER_GROUP(sb);
 990        for (i = 0; i < reserved_gdb; i++) {
 991                int err2;
 992                data = (__le32 *)primary[i]->b_data;
 993                /* printk("reserving backup %lu[%u] = %lu\n",
 994                       primary[i]->b_blocknr, gdbackups,
 995                       blk + primary[i]->b_blocknr); */
 996                data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 997                err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
 998                if (!err)
 999                        err = err2;
1000        }
1001        inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
1002        ext4_mark_iloc_dirty(handle, inode, &iloc);
1003
1004exit_bh:
1005        while (--res >= 0)
1006                brelse(primary[res]);
1007        brelse(dind);
1008
1009exit_free:
1010        kfree(primary);
1011
1012        return err;
1013}
1014
1015/*
1016 * Update the backup copies of the ext4 metadata.  These don't need to be part
1017 * of the main resize transaction, because e2fsck will re-write them if there
1018 * is a problem (basically only OOM will cause a problem).  However, we
1019 * _should_ update the backups if possible, in case the primary gets trashed
1020 * for some reason and we need to run e2fsck from a backup superblock.  The
1021 * important part is that the new block and inode counts are in the backup
1022 * superblocks, and the location of the new group metadata in the GDT backups.
1023 *
1024 * We do not need take the s_resize_lock for this, because these
1025 * blocks are not otherwise touched by the filesystem code when it is
1026 * mounted.  We don't need to worry about last changing from
1027 * sbi->s_groups_count, because the worst that can happen is that we
1028 * do not copy the full number of backups at this time.  The resize
1029 * which changed s_groups_count will backup again.
1030 */
1031static void update_backups(struct super_block *sb, int blk_off, char *data,
1032                           int size, int meta_bg)
1033{
1034        struct ext4_sb_info *sbi = EXT4_SB(sb);
1035        ext4_group_t last;
1036        const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1037        unsigned three = 1;
1038        unsigned five = 5;
1039        unsigned seven = 7;
1040        ext4_group_t group = 0;
1041        int rest = sb->s_blocksize - size;
1042        handle_t *handle;
1043        int err = 0, err2;
1044
1045        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
1046        if (IS_ERR(handle)) {
1047                group = 1;
1048                err = PTR_ERR(handle);
1049                goto exit_err;
1050        }
1051
1052        if (meta_bg == 0) {
1053                group = ext4_list_backups(sb, &three, &five, &seven);
1054                last = sbi->s_groups_count;
1055        } else {
1056                group = ext4_meta_bg_first_group(sb, group) + 1;
1057                last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1058        }
1059
1060        while (group < sbi->s_groups_count) {
1061                struct buffer_head *bh;
1062                ext4_fsblk_t backup_block;
1063
1064                /* Out of journal space, and can't get more - abort - so sad */
1065                if (ext4_handle_valid(handle) &&
1066                    handle->h_buffer_credits == 0 &&
1067                    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1068                    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1069                        break;
1070
1071                if (meta_bg == 0)
1072                        backup_block = group * bpg + blk_off;
1073                else
1074                        backup_block = (ext4_group_first_block_no(sb, group) +
1075                                        ext4_bg_has_super(sb, group));
1076
1077                bh = sb_getblk(sb, backup_block);
1078                if (!bh) {
1079                        err = -EIO;
1080                        break;
1081                }
1082                ext4_debug("update metadata backup %llu(+%llu)\n",
1083                           backup_block, backup_block -
1084                           ext4_group_first_block_no(sb, group));
1085                if ((err = ext4_journal_get_write_access(handle, bh)))
1086                        break;
1087                lock_buffer(bh);
1088                memcpy(bh->b_data, data, size);
1089                if (rest)
1090                        memset(bh->b_data + size, 0, rest);
1091                set_buffer_uptodate(bh);
1092                unlock_buffer(bh);
1093                err = ext4_handle_dirty_metadata(handle, NULL, bh);
1094                if (unlikely(err))
1095                        ext4_std_error(sb, err);
1096                brelse(bh);
1097
1098                if (meta_bg == 0)
1099                        group = ext4_list_backups(sb, &three, &five, &seven);
1100                else if (group == last)
1101                        break;
1102                else
1103                        group = last;
1104        }
1105        if ((err2 = ext4_journal_stop(handle)) && !err)
1106                err = err2;
1107
1108        /*
1109         * Ugh! Need to have e2fsck write the backup copies.  It is too
1110         * late to revert the resize, we shouldn't fail just because of
1111         * the backup copies (they are only needed in case of corruption).
1112         *
1113         * However, if we got here we have a journal problem too, so we
1114         * can't really start a transaction to mark the superblock.
1115         * Chicken out and just set the flag on the hope it will be written
1116         * to disk, and if not - we will simply wait until next fsck.
1117         */
1118exit_err:
1119        if (err) {
1120                ext4_warning(sb, "can't update backup for group %u (err %d), "
1121                             "forcing fsck on next reboot", group, err);
1122                sbi->s_mount_state &= ~EXT4_VALID_FS;
1123                sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1124                mark_buffer_dirty(sbi->s_sbh);
1125        }
1126}
1127
1128/*
1129 * ext4_add_new_descs() adds @count group descriptor of groups
1130 * starting at @group
1131 *
1132 * @handle: journal handle
1133 * @sb: super block
1134 * @group: the group no. of the first group desc to be added
1135 * @resize_inode: the resize inode
1136 * @count: number of group descriptors to be added
1137 */
1138static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1139                              ext4_group_t group, struct inode *resize_inode,
1140                              ext4_group_t count)
1141{
1142        struct ext4_sb_info *sbi = EXT4_SB(sb);
1143        struct ext4_super_block *es = sbi->s_es;
1144        struct buffer_head *gdb_bh;
1145        int i, gdb_off, gdb_num, err = 0;
1146        int meta_bg;
1147
1148        meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1149        for (i = 0; i < count; i++, group++) {
1150                int reserved_gdb = ext4_bg_has_super(sb, group) ?
1151                        le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1152
1153                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1154                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1155
1156                /*
1157                 * We will only either add reserved group blocks to a backup group
1158                 * or remove reserved blocks for the first group in a new group block.
1159                 * Doing both would be mean more complex code, and sane people don't
1160                 * use non-sparse filesystems anymore.  This is already checked above.
1161                 */
1162                if (gdb_off) {
1163                        gdb_bh = sbi->s_group_desc[gdb_num];
1164                        err = ext4_journal_get_write_access(handle, gdb_bh);
1165
1166                        if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1167                                err = reserve_backup_gdb(handle, resize_inode, group);
1168                } else if (meta_bg != 0) {
1169                        err = add_new_gdb_meta_bg(sb, handle, group);
1170                } else {
1171                        err = add_new_gdb(handle, resize_inode, group);
1172                }
1173                if (err)
1174                        break;
1175        }
1176        return err;
1177}
1178
1179static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1180{
1181        struct buffer_head *bh = sb_getblk(sb, block);
1182        if (!bh)
1183                return NULL;
1184        if (!bh_uptodate_or_lock(bh)) {
1185                if (bh_submit_read(bh) < 0) {
1186                        brelse(bh);
1187                        return NULL;
1188                }
1189        }
1190
1191        return bh;
1192}
1193
1194static int ext4_set_bitmap_checksums(struct super_block *sb,
1195                                     ext4_group_t group,
1196                                     struct ext4_group_desc *gdp,
1197                                     struct ext4_new_group_data *group_data)
1198{
1199        struct buffer_head *bh;
1200
1201        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1202                                        EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1203                return 0;
1204
1205        bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1206        if (!bh)
1207                return -EIO;
1208        ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1209                                   EXT4_INODES_PER_GROUP(sb) / 8);
1210        brelse(bh);
1211
1212        bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1213        if (!bh)
1214                return -EIO;
1215        ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1216        brelse(bh);
1217
1218        return 0;
1219}
1220
1221/*
1222 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1223 */
1224static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1225                                struct ext4_new_flex_group_data *flex_gd)
1226{
1227        struct ext4_new_group_data      *group_data = flex_gd->groups;
1228        struct ext4_group_desc          *gdp;
1229        struct ext4_sb_info             *sbi = EXT4_SB(sb);
1230        struct buffer_head              *gdb_bh;
1231        ext4_group_t                    group;
1232        __u16                           *bg_flags = flex_gd->bg_flags;
1233        int                             i, gdb_off, gdb_num, err = 0;
1234        
1235
1236        for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1237                group = group_data->group;
1238
1239                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1240                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1241
1242                /*
1243                 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1244                 */
1245                gdb_bh = sbi->s_group_desc[gdb_num];
1246                /* Update group descriptor block for new group */
1247                gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1248                                                 gdb_off * EXT4_DESC_SIZE(sb));
1249
1250                memset(gdp, 0, EXT4_DESC_SIZE(sb));
1251                ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1252                ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1253                err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1254                if (err) {
1255                        ext4_std_error(sb, err);
1256                        break;
1257                }
1258
1259                ext4_inode_table_set(sb, gdp, group_data->inode_table);
1260                ext4_free_group_clusters_set(sb, gdp,
1261                                             EXT4_B2C(sbi, group_data->free_blocks_count));
1262                ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1263                if (ext4_has_group_desc_csum(sb))
1264                        ext4_itable_unused_set(sb, gdp,
1265                                               EXT4_INODES_PER_GROUP(sb));
1266                gdp->bg_flags = cpu_to_le16(*bg_flags);
1267                ext4_group_desc_csum_set(sb, group, gdp);
1268
1269                err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1270                if (unlikely(err)) {
1271                        ext4_std_error(sb, err);
1272                        break;
1273                }
1274
1275                /*
1276                 * We can allocate memory for mb_alloc based on the new group
1277                 * descriptor
1278                 */
1279                err = ext4_mb_add_groupinfo(sb, group, gdp);
1280                if (err)
1281                        break;
1282        }
1283        return err;
1284}
1285
1286/*
1287 * ext4_update_super() updates the super block so that the newly added
1288 * groups can be seen by the filesystem.
1289 *
1290 * @sb: super block
1291 * @flex_gd: new added groups
1292 */
1293static void ext4_update_super(struct super_block *sb,
1294                             struct ext4_new_flex_group_data *flex_gd)
1295{
1296        ext4_fsblk_t blocks_count = 0;
1297        ext4_fsblk_t free_blocks = 0;
1298        ext4_fsblk_t reserved_blocks = 0;
1299        struct ext4_new_group_data *group_data = flex_gd->groups;
1300        struct ext4_sb_info *sbi = EXT4_SB(sb);
1301        struct ext4_super_block *es = sbi->s_es;
1302        int i;
1303
1304        BUG_ON(flex_gd->count == 0 || group_data == NULL);
1305        /*
1306         * Make the new blocks and inodes valid next.  We do this before
1307         * increasing the group count so that once the group is enabled,
1308         * all of its blocks and inodes are already valid.
1309         *
1310         * We always allocate group-by-group, then block-by-block or
1311         * inode-by-inode within a group, so enabling these
1312         * blocks/inodes before the group is live won't actually let us
1313         * allocate the new space yet.
1314         */
1315        for (i = 0; i < flex_gd->count; i++) {
1316                blocks_count += group_data[i].blocks_count;
1317                free_blocks += group_data[i].free_blocks_count;
1318        }
1319
1320        reserved_blocks = ext4_r_blocks_count(es) * 100;
1321        reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1322        reserved_blocks *= blocks_count;
1323        do_div(reserved_blocks, 100);
1324
1325        ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1326        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1327        le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1328                     flex_gd->count);
1329        le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1330                     flex_gd->count);
1331
1332        ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1333        /*
1334         * We need to protect s_groups_count against other CPUs seeing
1335         * inconsistent state in the superblock.
1336         *
1337         * The precise rules we use are:
1338         *
1339         * * Writers must perform a smp_wmb() after updating all
1340         *   dependent data and before modifying the groups count
1341         *
1342         * * Readers must perform an smp_rmb() after reading the groups
1343         *   count and before reading any dependent data.
1344         *
1345         * NB. These rules can be relaxed when checking the group count
1346         * while freeing data, as we can only allocate from a block
1347         * group after serialising against the group count, and we can
1348         * only then free after serialising in turn against that
1349         * allocation.
1350         */
1351        smp_wmb();
1352
1353        /* Update the global fs size fields */
1354        sbi->s_groups_count += flex_gd->count;
1355
1356        /* Update the reserved block counts only once the new group is
1357         * active. */
1358        ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1359                                reserved_blocks);
1360
1361        /* Update the free space counts */
1362        percpu_counter_add(&sbi->s_freeclusters_counter,
1363                           EXT4_B2C(sbi, free_blocks));
1364        percpu_counter_add(&sbi->s_freeinodes_counter,
1365                           EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1366
1367        ext4_debug("free blocks count %llu",
1368                   percpu_counter_read(&sbi->s_freeclusters_counter));
1369        if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1370                                      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1371            sbi->s_log_groups_per_flex) {
1372                ext4_group_t flex_group;
1373                flex_group = ext4_flex_group(sbi, group_data[0].group);
1374                atomic_add(EXT4_B2C(sbi, free_blocks),
1375                           &sbi->s_flex_groups[flex_group].free_clusters);
1376                atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1377                           &sbi->s_flex_groups[flex_group].free_inodes);
1378        }
1379
1380        /*
1381         * Update the fs overhead information
1382         */
1383        ext4_calculate_overhead(sb);
1384
1385        if (test_opt(sb, DEBUG))
1386                printk(KERN_DEBUG "EXT4-fs: added group %u:"
1387                       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1388                       blocks_count, free_blocks, reserved_blocks);
1389}
1390
1391/* Add a flex group to an fs. Ensure we handle all possible error conditions
1392 * _before_ we start modifying the filesystem, because we cannot abort the
1393 * transaction and not have it write the data to disk.
1394 */
1395static int ext4_flex_group_add(struct super_block *sb,
1396                               struct inode *resize_inode,
1397                               struct ext4_new_flex_group_data *flex_gd)
1398{
1399        struct ext4_sb_info *sbi = EXT4_SB(sb);
1400        struct ext4_super_block *es = sbi->s_es;
1401        ext4_fsblk_t o_blocks_count;
1402        ext4_grpblk_t last;
1403        ext4_group_t group;
1404        handle_t *handle;
1405        unsigned reserved_gdb;
1406        int err = 0, err2 = 0, credit;
1407
1408        BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1409
1410        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1411        o_blocks_count = ext4_blocks_count(es);
1412        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1413        BUG_ON(last);
1414
1415        err = setup_new_flex_group_blocks(sb, flex_gd);
1416        if (err)
1417                goto exit;
1418        /*
1419         * We will always be modifying at least the superblock and  GDT
1420         * block.  If we are adding a group past the last current GDT block,
1421         * we will also modify the inode and the dindirect block.  If we
1422         * are adding a group with superblock/GDT backups  we will also
1423         * modify each of the reserved GDT dindirect blocks.
1424         */
1425        credit = flex_gd->count * 4 + reserved_gdb;
1426        handle = ext4_journal_start_sb(sb, credit);
1427        if (IS_ERR(handle)) {
1428                err = PTR_ERR(handle);
1429                goto exit;
1430        }
1431
1432        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1433        if (err)
1434                goto exit_journal;
1435
1436        group = flex_gd->groups[0].group;
1437        BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1438        err = ext4_add_new_descs(handle, sb, group,
1439                                resize_inode, flex_gd->count);
1440        if (err)
1441                goto exit_journal;
1442
1443        err = ext4_setup_new_descs(handle, sb, flex_gd);
1444        if (err)
1445                goto exit_journal;
1446
1447        ext4_update_super(sb, flex_gd);
1448
1449        err = ext4_handle_dirty_super(handle, sb);
1450
1451exit_journal:
1452        err2 = ext4_journal_stop(handle);
1453        if (!err)
1454                err = err2;
1455
1456        if (!err) {
1457                int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1458                int gdb_num_end = ((group + flex_gd->count - 1) /
1459                                   EXT4_DESC_PER_BLOCK(sb));
1460                int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,
1461                                EXT4_FEATURE_INCOMPAT_META_BG);
1462                sector_t old_gdb = 0;
1463
1464                update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1465                               sizeof(struct ext4_super_block), 0);
1466                for (; gdb_num <= gdb_num_end; gdb_num++) {
1467                        struct buffer_head *gdb_bh;
1468
1469                        gdb_bh = sbi->s_group_desc[gdb_num];
1470                        if (old_gdb == gdb_bh->b_blocknr)
1471                                continue;
1472                        update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1473                                       gdb_bh->b_size, meta_bg);
1474                        old_gdb = gdb_bh->b_blocknr;
1475                }
1476        }
1477exit:
1478        return err;
1479}
1480
1481static int ext4_setup_next_flex_gd(struct super_block *sb,
1482                                    struct ext4_new_flex_group_data *flex_gd,
1483                                    ext4_fsblk_t n_blocks_count,
1484                                    unsigned long flexbg_size)
1485{
1486        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1487        struct ext4_new_group_data *group_data = flex_gd->groups;
1488        ext4_fsblk_t o_blocks_count;
1489        ext4_group_t n_group;
1490        ext4_group_t group;
1491        ext4_group_t last_group;
1492        ext4_grpblk_t last;
1493        ext4_grpblk_t blocks_per_group;
1494        unsigned long i;
1495
1496        blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1497
1498        o_blocks_count = ext4_blocks_count(es);
1499
1500        if (o_blocks_count == n_blocks_count)
1501                return 0;
1502
1503        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1504        BUG_ON(last);
1505        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1506
1507        last_group = group | (flexbg_size - 1);
1508        if (last_group > n_group)
1509                last_group = n_group;
1510
1511        flex_gd->count = last_group - group + 1;
1512
1513        for (i = 0; i < flex_gd->count; i++) {
1514                int overhead;
1515
1516                group_data[i].group = group + i;
1517                group_data[i].blocks_count = blocks_per_group;
1518                overhead = ext4_group_overhead_blocks(sb, group + i);
1519                group_data[i].free_blocks_count = blocks_per_group - overhead;
1520                if (ext4_has_group_desc_csum(sb))
1521                        flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1522                                               EXT4_BG_INODE_UNINIT;
1523                else
1524                        flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1525        }
1526
1527        if (last_group == n_group && ext4_has_group_desc_csum(sb))
1528                /* We need to initialize block bitmap of last group. */
1529                flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1530
1531        if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1532                group_data[i - 1].blocks_count = last + 1;
1533                group_data[i - 1].free_blocks_count -= blocks_per_group-
1534                                        last - 1;
1535        }
1536
1537        return 1;
1538}
1539
1540/* Add group descriptor data to an existing or new group descriptor block.
1541 * Ensure we handle all possible error conditions _before_ we start modifying
1542 * the filesystem, because we cannot abort the transaction and not have it
1543 * write the data to disk.
1544 *
1545 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1546 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1547 *
1548 * We only need to hold the superblock lock while we are actually adding
1549 * in the new group's counts to the superblock.  Prior to that we have
1550 * not really "added" the group at all.  We re-check that we are still
1551 * adding in the last group in case things have changed since verifying.
1552 */
1553int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1554{
1555        struct ext4_new_flex_group_data flex_gd;
1556        struct ext4_sb_info *sbi = EXT4_SB(sb);
1557        struct ext4_super_block *es = sbi->s_es;
1558        int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1559                le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1560        struct inode *inode = NULL;
1561        int gdb_off, gdb_num;
1562        int err;
1563        __u16 bg_flags = 0;
1564
1565        gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1566        gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1567
1568        if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1569                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1570                ext4_warning(sb, "Can't resize non-sparse filesystem further");
1571                return -EPERM;
1572        }
1573
1574        if (ext4_blocks_count(es) + input->blocks_count <
1575            ext4_blocks_count(es)) {
1576                ext4_warning(sb, "blocks_count overflow");
1577                return -EINVAL;
1578        }
1579
1580        if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1581            le32_to_cpu(es->s_inodes_count)) {
1582                ext4_warning(sb, "inodes_count overflow");
1583                return -EINVAL;
1584        }
1585
1586        if (reserved_gdb || gdb_off == 0) {
1587                if (!EXT4_HAS_COMPAT_FEATURE(sb,
1588                                             EXT4_FEATURE_COMPAT_RESIZE_INODE)
1589                    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1590                        ext4_warning(sb,
1591                                     "No reserved GDT blocks, can't resize");
1592                        return -EPERM;
1593                }
1594                inode = ext4_iget(sb, EXT4_RESIZE_INO);
1595                if (IS_ERR(inode)) {
1596                        ext4_warning(sb, "Error opening resize inode");
1597                        return PTR_ERR(inode);
1598                }
1599        }
1600
1601
1602        err = verify_group_input(sb, input);
1603        if (err)
1604                goto out;
1605
1606        err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1607        if (err)
1608                return err;
1609
1610        err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1611        if (err)
1612                goto out;
1613
1614        flex_gd.count = 1;
1615        flex_gd.groups = input;
1616        flex_gd.bg_flags = &bg_flags;
1617        err = ext4_flex_group_add(sb, inode, &flex_gd);
1618out:
1619        iput(inode);
1620        return err;
1621} /* ext4_group_add */
1622
1623/*
1624 * extend a group without checking assuming that checking has been done.
1625 */
1626static int ext4_group_extend_no_check(struct super_block *sb,
1627                                      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1628{
1629        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1630        handle_t *handle;
1631        int err = 0, err2;
1632
1633        /* We will update the superblock, one block bitmap, and
1634         * one group descriptor via ext4_group_add_blocks().
1635         */
1636        handle = ext4_journal_start_sb(sb, 3);
1637        if (IS_ERR(handle)) {
1638                err = PTR_ERR(handle);
1639                ext4_warning(sb, "error %d on journal start", err);
1640                return err;
1641        }
1642
1643        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1644        if (err) {
1645                ext4_warning(sb, "error %d on journal write access", err);
1646                goto errout;
1647        }
1648
1649        ext4_blocks_count_set(es, o_blocks_count + add);
1650        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1651        ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1652                   o_blocks_count + add);
1653        /* We add the blocks to the bitmap and set the group need init bit */
1654        err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1655        if (err)
1656                goto errout;
1657        ext4_handle_dirty_super(handle, sb);
1658        ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1659                   o_blocks_count + add);
1660errout:
1661        err2 = ext4_journal_stop(handle);
1662        if (err2 && !err)
1663                err = err2;
1664
1665        if (!err) {
1666                ext4_fsblk_t first_block;
1667                first_block = ext4_group_first_block_no(sb, 0);
1668                if (test_opt(sb, DEBUG))
1669                        printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1670                               "blocks\n", ext4_blocks_count(es));
1671                update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr - first_block,
1672                               (char *)es, sizeof(struct ext4_super_block), 0);
1673        }
1674        return err;
1675}
1676
1677/*
1678 * Extend the filesystem to the new number of blocks specified.  This entry
1679 * point is only used to extend the current filesystem to the end of the last
1680 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1681 * for emergencies (because it has no dependencies on reserved blocks).
1682 *
1683 * If we _really_ wanted, we could use default values to call ext4_group_add()
1684 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1685 * GDT blocks are reserved to grow to the desired size.
1686 */
1687int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1688                      ext4_fsblk_t n_blocks_count)
1689{
1690        ext4_fsblk_t o_blocks_count;
1691        ext4_grpblk_t last;
1692        ext4_grpblk_t add;
1693        struct buffer_head *bh;
1694        int err;
1695        ext4_group_t group;
1696
1697        o_blocks_count = ext4_blocks_count(es);
1698
1699        if (test_opt(sb, DEBUG))
1700                ext4_msg(sb, KERN_DEBUG,
1701                         "extending last group from %llu to %llu blocks",
1702                         o_blocks_count, n_blocks_count);
1703
1704        if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1705                return 0;
1706
1707        if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1708                ext4_msg(sb, KERN_ERR,
1709                         "filesystem too large to resize to %llu blocks safely",
1710                         n_blocks_count);
1711                if (sizeof(sector_t) < 8)
1712                        ext4_warning(sb, "CONFIG_LBDAF not enabled");
1713                return -EINVAL;
1714        }
1715
1716        if (n_blocks_count < o_blocks_count) {
1717                ext4_warning(sb, "can't shrink FS - resize aborted");
1718                return -EINVAL;
1719        }
1720
1721        /* Handle the remaining blocks in the last group only. */
1722        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1723
1724        if (last == 0) {
1725                ext4_warning(sb, "need to use ext2online to resize further");
1726                return -EPERM;
1727        }
1728
1729        add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1730
1731        if (o_blocks_count + add < o_blocks_count) {
1732                ext4_warning(sb, "blocks_count overflow");
1733                return -EINVAL;
1734        }
1735
1736        if (o_blocks_count + add > n_blocks_count)
1737                add = n_blocks_count - o_blocks_count;
1738
1739        if (o_blocks_count + add < n_blocks_count)
1740                ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1741                             o_blocks_count + add, add);
1742
1743        /* See if the device is actually as big as what was requested */
1744        bh = sb_bread(sb, o_blocks_count + add - 1);
1745        if (!bh) {
1746                ext4_warning(sb, "can't read last block, resize aborted");
1747                return -ENOSPC;
1748        }
1749        brelse(bh);
1750
1751        err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1752        return err;
1753} /* ext4_group_extend */
1754
1755
1756static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1757{
1758        return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1759}
1760
1761/*
1762 * Release the resize inode and drop the resize_inode feature if there
1763 * are no more reserved gdt blocks, and then convert the file system
1764 * to enable meta_bg
1765 */
1766static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1767{
1768        handle_t *handle;
1769        struct ext4_sb_info *sbi = EXT4_SB(sb);
1770        struct ext4_super_block *es = sbi->s_es;
1771        struct ext4_inode_info *ei = EXT4_I(inode);
1772        ext4_fsblk_t nr;
1773        int i, ret, err = 0;
1774        int credits = 1;
1775
1776        ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1777        if (inode) {
1778                if (es->s_reserved_gdt_blocks) {
1779                        ext4_error(sb, "Unexpected non-zero "
1780                                   "s_reserved_gdt_blocks");
1781                        return -EPERM;
1782                }
1783
1784                /* Do a quick sanity check of the resize inode */
1785                if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
1786                        goto invalid_resize_inode;
1787                for (i = 0; i < EXT4_N_BLOCKS; i++) {
1788                        if (i == EXT4_DIND_BLOCK) {
1789                                if (ei->i_data[i])
1790                                        continue;
1791                                else
1792                                        goto invalid_resize_inode;
1793                        }
1794                        if (ei->i_data[i])
1795                                goto invalid_resize_inode;
1796                }
1797                credits += 3;   /* block bitmap, bg descriptor, resize inode */
1798        }
1799
1800        handle = ext4_journal_start_sb(sb, credits);
1801        if (IS_ERR(handle))
1802                return PTR_ERR(handle);
1803
1804        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1805        if (err)
1806                goto errout;
1807
1808        EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
1809        EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1810        sbi->s_es->s_first_meta_bg =
1811                cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1812
1813        err = ext4_handle_dirty_super(handle, sb);
1814        if (err) {
1815                ext4_std_error(sb, err);
1816                goto errout;
1817        }
1818
1819        if (inode) {
1820                nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1821                ext4_free_blocks(handle, inode, NULL, nr, 1,
1822                                 EXT4_FREE_BLOCKS_METADATA |
1823                                 EXT4_FREE_BLOCKS_FORGET);
1824                ei->i_data[EXT4_DIND_BLOCK] = 0;
1825                inode->i_blocks = 0;
1826
1827                err = ext4_mark_inode_dirty(handle, inode);
1828                if (err)
1829                        ext4_std_error(sb, err);
1830        }
1831
1832errout:
1833        ret = ext4_journal_stop(handle);
1834        if (!err)
1835                err = ret;
1836        return ret;
1837
1838invalid_resize_inode:
1839        ext4_error(sb, "corrupted/inconsistent resize inode");
1840        return -EINVAL;
1841}
1842
1843/*
1844 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1845 *
1846 * @sb: super block of the fs to be resized
1847 * @n_blocks_count: the number of blocks resides in the resized fs
1848 */
1849int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1850{
1851        struct ext4_new_flex_group_data *flex_gd = NULL;
1852        struct ext4_sb_info *sbi = EXT4_SB(sb);
1853        struct ext4_super_block *es = sbi->s_es;
1854        struct buffer_head *bh;
1855        struct inode *resize_inode = NULL;
1856        ext4_grpblk_t add, offset;
1857        unsigned long n_desc_blocks;
1858        unsigned long o_desc_blocks;
1859        ext4_group_t o_group;
1860        ext4_group_t n_group;
1861        ext4_fsblk_t o_blocks_count;
1862        ext4_fsblk_t n_blocks_count_retry = 0;
1863        unsigned long last_update_time = 0;
1864        int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1865        int meta_bg;
1866
1867        /* See if the device is actually as big as what was requested */
1868        bh = sb_bread(sb, n_blocks_count - 1);
1869        if (!bh) {
1870                ext4_warning(sb, "can't read last block, resize aborted");
1871                return -ENOSPC;
1872        }
1873        brelse(bh);
1874
1875retry:
1876        o_blocks_count = ext4_blocks_count(es);
1877
1878        ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1879                 "to %llu blocks", o_blocks_count, n_blocks_count);
1880
1881        if (n_blocks_count < o_blocks_count) {
1882                /* On-line shrinking not supported */
1883                ext4_warning(sb, "can't shrink FS - resize aborted");
1884                return -EINVAL;
1885        }
1886
1887        if (n_blocks_count == o_blocks_count)
1888                /* Nothing need to do */
1889                return 0;
1890
1891        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
1892        ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1893
1894        n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1895        o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1896
1897        meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1898
1899        if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
1900                if (meta_bg) {
1901                        ext4_error(sb, "resize_inode and meta_bg enabled "
1902                                   "simultaneously");
1903                        return -EINVAL;
1904                }
1905                if (n_desc_blocks > o_desc_blocks +
1906                    le16_to_cpu(es->s_reserved_gdt_blocks)) {
1907                        n_blocks_count_retry = n_blocks_count;
1908                        n_desc_blocks = o_desc_blocks +
1909                                le16_to_cpu(es->s_reserved_gdt_blocks);
1910                        n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1911                        n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
1912                        n_group--; /* set to last group number */
1913                }
1914
1915                if (!resize_inode)
1916                        resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1917                if (IS_ERR(resize_inode)) {
1918                        ext4_warning(sb, "Error opening resize inode");
1919                        return PTR_ERR(resize_inode);
1920                }
1921        }
1922
1923        if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1924                err = ext4_convert_meta_bg(sb, resize_inode);
1925                if (err)
1926                        goto out;
1927                if (resize_inode) {
1928                        iput(resize_inode);
1929                        resize_inode = NULL;
1930                }
1931                if (n_blocks_count_retry) {
1932                        n_blocks_count = n_blocks_count_retry;
1933                        n_blocks_count_retry = 0;
1934                        goto retry;
1935                }
1936        }
1937
1938        /* extend the last group */
1939        if (n_group == o_group)
1940                add = n_blocks_count - o_blocks_count;
1941        else
1942                add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1943        if (add > 0) {
1944                err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1945                if (err)
1946                        goto out;
1947        }
1948
1949        if (ext4_blocks_count(es) == n_blocks_count)
1950                goto out;
1951
1952        err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1953        if (err)
1954                return err;
1955
1956        err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1957        if (err)
1958                goto out;
1959
1960        flex_gd = alloc_flex_gd(flexbg_size);
1961        if (flex_gd == NULL) {
1962                err = -ENOMEM;
1963                goto out;
1964        }
1965
1966        /* Add flex groups. Note that a regular group is a
1967         * flex group with 1 group.
1968         */
1969        while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1970                                              flexbg_size)) {
1971                if (jiffies - last_update_time > HZ * 10) {
1972                        if (last_update_time)
1973                                ext4_msg(sb, KERN_INFO,
1974                                         "resized to %llu blocks",
1975                                         ext4_blocks_count(es));
1976                        last_update_time = jiffies;
1977                }
1978                if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1979                        break;
1980                err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1981                if (unlikely(err))
1982                        break;
1983        }
1984
1985        if (!err && n_blocks_count_retry) {
1986                n_blocks_count = n_blocks_count_retry;
1987                n_blocks_count_retry = 0;
1988                free_flex_gd(flex_gd);
1989                flex_gd = NULL;
1990                goto retry;
1991        }
1992
1993out:
1994        if (flex_gd)
1995                free_flex_gd(flex_gd);
1996        if (resize_inode != NULL)
1997                iput(resize_inode);
1998        ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
1999        return err;
2000}
2001
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