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
  48#define outside(b, first, last) ((b) < (first) || (b) >= (last))
  49#define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  50
  51static int verify_group_input(struct super_block *sb,
  52                              struct ext4_new_group_data *input)
  53{
  54        struct ext4_sb_info *sbi = EXT4_SB(sb);
  55        struct ext4_super_block *es = sbi->s_es;
  56        ext4_fsblk_t start = ext4_blocks_count(es);
  57        ext4_fsblk_t end = start + input->blocks_count;
  58        ext4_group_t group = input->group;
  59        ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  60        unsigned overhead = ext4_bg_has_super(sb, group) ?
  61                (1 + ext4_bg_num_gdb(sb, group) +
  62                 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
  63        ext4_fsblk_t metaend = start + overhead;
  64        struct buffer_head *bh = NULL;
  65        ext4_grpblk_t free_blocks_count, offset;
  66        int err = -EINVAL;
  67
  68        input->free_blocks_count = free_blocks_count =
  69                input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
  70
  71        if (test_opt(sb, DEBUG))
  72                printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
  73                       "(%d free, %u reserved)\n",
  74                       ext4_bg_has_super(sb, input->group) ? "normal" :
  75                       "no-super", input->group, input->blocks_count,
  76                       free_blocks_count, input->reserved_blocks);
  77
  78        ext4_get_group_no_and_offset(sb, start, NULL, &offset);
  79        if (group != sbi->s_groups_count)
  80                ext4_warning(sb, "Cannot add at group %u (only %u groups)",
  81                             input->group, sbi->s_groups_count);
  82        else if (offset != 0)
  83                        ext4_warning(sb, "Last group not full");
  84        else if (input->reserved_blocks > input->blocks_count / 5)
  85                ext4_warning(sb, "Reserved blocks too high (%u)",
  86                             input->reserved_blocks);
  87        else if (free_blocks_count < 0)
  88                ext4_warning(sb, "Bad blocks count %u",
  89                             input->blocks_count);
  90        else if (!(bh = sb_bread(sb, end - 1)))
  91                ext4_warning(sb, "Cannot read last block (%llu)",
  92                             end - 1);
  93        else if (outside(input->block_bitmap, start, end))
  94                ext4_warning(sb, "Block bitmap not in group (block %llu)",
  95                             (unsigned long long)input->block_bitmap);
  96        else if (outside(input->inode_bitmap, start, end))
  97                ext4_warning(sb, "Inode bitmap not in group (block %llu)",
  98                             (unsigned long long)input->inode_bitmap);
  99        else if (outside(input->inode_table, start, end) ||
 100                 outside(itend - 1, start, end))
 101                ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 102                             (unsigned long long)input->inode_table, itend - 1);
 103        else if (input->inode_bitmap == input->block_bitmap)
 104                ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 105                             (unsigned long long)input->block_bitmap);
 106        else if (inside(input->block_bitmap, input->inode_table, itend))
 107                ext4_warning(sb, "Block bitmap (%llu) in inode table "
 108                             "(%llu-%llu)",
 109                             (unsigned long long)input->block_bitmap,
 110                             (unsigned long long)input->inode_table, itend - 1);
 111        else if (inside(input->inode_bitmap, input->inode_table, itend))
 112                ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 113                             "(%llu-%llu)",
 114                             (unsigned long long)input->inode_bitmap,
 115                             (unsigned long long)input->inode_table, itend - 1);
 116        else if (inside(input->block_bitmap, start, metaend))
 117                ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 118                             (unsigned long long)input->block_bitmap,
 119                             start, metaend - 1);
 120        else if (inside(input->inode_bitmap, start, metaend))
 121                ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 122                             (unsigned long long)input->inode_bitmap,
 123                             start, metaend - 1);
 124        else if (inside(input->inode_table, start, metaend) ||
 125                 inside(itend - 1, start, metaend))
 126                ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 127                             "(%llu-%llu)",
 128                             (unsigned long long)input->inode_table,
 129                             itend - 1, start, metaend - 1);
 130        else
 131                err = 0;
 132        brelse(bh);
 133
 134        return err;
 135}
 136
 137/*
 138 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 139 * group each time.
 140 */
 141struct ext4_new_flex_group_data {
 142        struct ext4_new_group_data *groups;     /* new_group_data for groups
 143                                                   in the flex group */
 144        __u16 *bg_flags;                        /* block group flags of groups
 145                                                   in @groups */
 146        ext4_group_t count;                     /* number of groups in @groups
 147                                                 */
 148};
 149
 150/*
 151 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 152 * @flexbg_size.
 153 *
 154 * Returns NULL on failure otherwise address of the allocated structure.
 155 */
 156static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 157{
 158        struct ext4_new_flex_group_data *flex_gd;
 159
 160        flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 161        if (flex_gd == NULL)
 162                goto out3;
 163
 164        if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
 165                goto out2;
 166        flex_gd->count = flexbg_size;
 167
 168        flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
 169                                  flexbg_size, GFP_NOFS);
 170        if (flex_gd->groups == NULL)
 171                goto out2;
 172
 173        flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
 174        if (flex_gd->bg_flags == NULL)
 175                goto out1;
 176
 177        return flex_gd;
 178
 179out1:
 180        kfree(flex_gd->groups);
 181out2:
 182        kfree(flex_gd);
 183out3:
 184        return NULL;
 185}
 186
 187static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 188{
 189        kfree(flex_gd->bg_flags);
 190        kfree(flex_gd->groups);
 191        kfree(flex_gd);
 192}
 193
 194/*
 195 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 196 * and inode tables for a flex group.
 197 *
 198 * This function is used by 64bit-resize.  Note that this function allocates
 199 * group tables from the 1st group of groups contained by @flexgd, which may
 200 * be a partial of a flex group.
 201 *
 202 * @sb: super block of fs to which the groups belongs
 203 *
 204 * Returns 0 on a successful allocation of the metadata blocks in the
 205 * block group.
 206 */
 207static int ext4_alloc_group_tables(struct super_block *sb,
 208                                struct ext4_new_flex_group_data *flex_gd,
 209                                int flexbg_size)
 210{
 211        struct ext4_new_group_data *group_data = flex_gd->groups;
 212        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 213        ext4_fsblk_t start_blk;
 214        ext4_fsblk_t last_blk;
 215        ext4_group_t src_group;
 216        ext4_group_t bb_index = 0;
 217        ext4_group_t ib_index = 0;
 218        ext4_group_t it_index = 0;
 219        ext4_group_t group;
 220        ext4_group_t last_group;
 221        unsigned overhead;
 222
 223        BUG_ON(flex_gd->count == 0 || group_data == NULL);
 224
 225        src_group = group_data[0].group;
 226        last_group  = src_group + flex_gd->count - 1;
 227
 228        BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 229               (last_group & ~(flexbg_size - 1))));
 230next_group:
 231        group = group_data[0].group;
 232        if (src_group >= group_data[0].group + flex_gd->count)
 233                return -ENOSPC;
 234        start_blk = ext4_group_first_block_no(sb, src_group);
 235        last_blk = start_blk + group_data[src_group - group].blocks_count;
 236
 237        overhead = ext4_bg_has_super(sb, src_group) ?
 238                   (1 + ext4_bg_num_gdb(sb, src_group) +
 239                    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
 240
 241        start_blk += overhead;
 242
 243        /* We collect contiguous blocks as much as possible. */
 244        src_group++;
 245        for (; src_group <= last_group; src_group++)
 246                if (!ext4_bg_has_super(sb, src_group))
 247                        last_blk += group_data[src_group - group].blocks_count;
 248                else
 249                        break;
 250
 251        /* Allocate block bitmaps */
 252        for (; bb_index < flex_gd->count; bb_index++) {
 253                if (start_blk >= last_blk)
 254                        goto next_group;
 255                group_data[bb_index].block_bitmap = start_blk++;
 256                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 257                group -= group_data[0].group;
 258                group_data[group].free_blocks_count--;
 259                if (flexbg_size > 1)
 260                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 261        }
 262
 263        /* Allocate inode bitmaps */
 264        for (; ib_index < flex_gd->count; ib_index++) {
 265                if (start_blk >= last_blk)
 266                        goto next_group;
 267                group_data[ib_index].inode_bitmap = start_blk++;
 268                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 269                group -= group_data[0].group;
 270                group_data[group].free_blocks_count--;
 271                if (flexbg_size > 1)
 272                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 273        }
 274
 275        /* Allocate inode tables */
 276        for (; it_index < flex_gd->count; it_index++) {
 277                if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
 278                        goto next_group;
 279                group_data[it_index].inode_table = start_blk;
 280                ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
 281                group -= group_data[0].group;
 282                group_data[group].free_blocks_count -=
 283                                        EXT4_SB(sb)->s_itb_per_group;
 284                if (flexbg_size > 1)
 285                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 286
 287                start_blk += EXT4_SB(sb)->s_itb_per_group;
 288        }
 289
 290        if (test_opt(sb, DEBUG)) {
 291                int i;
 292                group = group_data[0].group;
 293
 294                printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 295                       "%d groups, flexbg size is %d:\n", flex_gd->count,
 296                       flexbg_size);
 297
 298                for (i = 0; i < flex_gd->count; i++) {
 299                        printk(KERN_DEBUG "adding %s group %u: %u "
 300                               "blocks (%d free)\n",
 301                               ext4_bg_has_super(sb, group + i) ? "normal" :
 302                               "no-super", group + i,
 303                               group_data[i].blocks_count,
 304                               group_data[i].free_blocks_count);
 305                }
 306        }
 307        return 0;
 308}
 309
 310static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 311                                  ext4_fsblk_t blk)
 312{
 313        struct buffer_head *bh;
 314        int err;
 315
 316        bh = sb_getblk(sb, blk);
 317        if (!bh)
 318                return ERR_PTR(-EIO);
 319        if ((err = ext4_journal_get_write_access(handle, bh))) {
 320                brelse(bh);
 321                bh = ERR_PTR(err);
 322        } else {
 323                memset(bh->b_data, 0, sb->s_blocksize);
 324                set_buffer_uptodate(bh);
 325        }
 326
 327        return bh;
 328}
 329
 330/*
 331 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 332 * If that fails, restart the transaction & regain write access for the
 333 * buffer head which is used for block_bitmap modifications.
 334 */
 335static int extend_or_restart_transaction(handle_t *handle, int thresh)
 336{
 337        int err;
 338
 339        if (ext4_handle_has_enough_credits(handle, thresh))
 340                return 0;
 341
 342        err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 343        if (err < 0)
 344                return err;
 345        if (err) {
 346                err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 347                if (err)
 348                        return err;
 349        }
 350
 351        return 0;
 352}
 353
 354/*
 355 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 356 *
 357 * Helper function for ext4_setup_new_group_blocks() which set .
 358 *
 359 * @sb: super block
 360 * @handle: journal handle
 361 * @flex_gd: flex group data
 362 */
 363static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 364                        struct ext4_new_flex_group_data *flex_gd,
 365                        ext4_fsblk_t block, ext4_group_t count)
 366{
 367        ext4_group_t count2;
 368
 369        ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 370        for (count2 = count; count > 0; count -= count2, block += count2) {
 371                ext4_fsblk_t start;
 372                struct buffer_head *bh;
 373                ext4_group_t group;
 374                int err;
 375
 376                ext4_get_group_no_and_offset(sb, block, &group, NULL);
 377                start = ext4_group_first_block_no(sb, group);
 378                group -= flex_gd->groups[0].group;
 379
 380                count2 = sb->s_blocksize * 8 - (block - start);
 381                if (count2 > count)
 382                        count2 = count;
 383
 384                if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 385                        BUG_ON(flex_gd->count > 1);
 386                        continue;
 387                }
 388
 389                err = extend_or_restart_transaction(handle, 1);
 390                if (err)
 391                        return err;
 392
 393                bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 394                if (!bh)
 395                        return -EIO;
 396
 397                err = ext4_journal_get_write_access(handle, bh);
 398                if (err)
 399                        return err;
 400                ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 401                           block - start, count2);
 402                ext4_set_bits(bh->b_data, block - start, count2);
 403
 404                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 405                if (unlikely(err))
 406                        return err;
 407                brelse(bh);
 408        }
 409
 410        return 0;
 411}
 412
 413/*
 414 * Set up the block and inode bitmaps, and the inode table for the new groups.
 415 * This doesn't need to be part of the main transaction, since we are only
 416 * changing blocks outside the actual filesystem.  We still do journaling to
 417 * ensure the recovery is correct in case of a failure just after resize.
 418 * If any part of this fails, we simply abort the resize.
 419 *
 420 * setup_new_flex_group_blocks handles a flex group as follow:
 421 *  1. copy super block and GDT, and initialize group tables if necessary.
 422 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 423 *     super block and GDT.
 424 *  2. allocate group tables in block bitmaps, that is, set bits in block
 425 *     bitmap for blocks taken by group tables.
 426 */
 427static int setup_new_flex_group_blocks(struct super_block *sb,
 428                                struct ext4_new_flex_group_data *flex_gd)
 429{
 430        int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 431        ext4_fsblk_t start;
 432        ext4_fsblk_t block;
 433        struct ext4_sb_info *sbi = EXT4_SB(sb);
 434        struct ext4_super_block *es = sbi->s_es;
 435        struct ext4_new_group_data *group_data = flex_gd->groups;
 436        __u16 *bg_flags = flex_gd->bg_flags;
 437        handle_t *handle;
 438        ext4_group_t group, count;
 439        struct buffer_head *bh = NULL;
 440        int reserved_gdb, i, j, err = 0, err2;
 441
 442        BUG_ON(!flex_gd->count || !group_data ||
 443               group_data[0].group != sbi->s_groups_count);
 444
 445        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 446
 447        /* This transaction may be extended/restarted along the way */
 448        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 449        if (IS_ERR(handle))
 450                return PTR_ERR(handle);
 451
 452        group = group_data[0].group;
 453        for (i = 0; i < flex_gd->count; i++, group++) {
 454                unsigned long gdblocks;
 455
 456                gdblocks = ext4_bg_num_gdb(sb, group);
 457                start = ext4_group_first_block_no(sb, group);
 458
 459                if (!ext4_bg_has_super(sb, group))
 460                        goto handle_itb;
 461
 462                /* Copy all of the GDT blocks into the backup in this group */
 463                for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
 464                        struct buffer_head *gdb;
 465
 466                        ext4_debug("update backup group %#04llx\n", block);
 467                        err = extend_or_restart_transaction(handle, 1);
 468                        if (err)
 469                                goto out;
 470
 471                        gdb = sb_getblk(sb, block);
 472                        if (!gdb) {
 473                                err = -EIO;
 474                                goto out;
 475                        }
 476
 477                        err = ext4_journal_get_write_access(handle, gdb);
 478                        if (err) {
 479                                brelse(gdb);
 480                                goto out;
 481                        }
 482                        memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 483                               gdb->b_size);
 484                        set_buffer_uptodate(gdb);
 485
 486                        err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 487                        if (unlikely(err)) {
 488                                brelse(gdb);
 489                                goto out;
 490                        }
 491                        brelse(gdb);
 492                }
 493
 494                /* Zero out all of the reserved backup group descriptor
 495                 * table blocks
 496                 */
 497                if (ext4_bg_has_super(sb, group)) {
 498                        err = sb_issue_zeroout(sb, gdblocks + start + 1,
 499                                        reserved_gdb, GFP_NOFS);
 500                        if (err)
 501                                goto out;
 502                }
 503
 504handle_itb:
 505                /* Initialize group tables of the grop @group */
 506                if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 507                        goto handle_bb;
 508
 509                /* Zero out all of the inode table blocks */
 510                block = group_data[i].inode_table;
 511                ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 512                           block, sbi->s_itb_per_group);
 513                err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 514                                       GFP_NOFS);
 515                if (err)
 516                        goto out;
 517
 518handle_bb:
 519                if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 520                        goto handle_ib;
 521
 522                /* Initialize block bitmap of the @group */
 523                block = group_data[i].block_bitmap;
 524                err = extend_or_restart_transaction(handle, 1);
 525                if (err)
 526                        goto out;
 527
 528                bh = bclean(handle, sb, block);
 529                if (IS_ERR(bh)) {
 530                        err = PTR_ERR(bh);
 531                        goto out;
 532                }
 533                if (ext4_bg_has_super(sb, group)) {
 534                        ext4_debug("mark backup superblock %#04llx (+0)\n",
 535                                   start);
 536                        ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
 537                                                     1);
 538                }
 539                ext4_mark_bitmap_end(group_data[i].blocks_count,
 540                                     sb->s_blocksize * 8, bh->b_data);
 541                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 542                if (err)
 543                        goto out;
 544                brelse(bh);
 545
 546handle_ib:
 547                if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 548                        continue;
 549
 550                /* Initialize inode bitmap of the @group */
 551                block = group_data[i].inode_bitmap;
 552                err = extend_or_restart_transaction(handle, 1);
 553                if (err)
 554                        goto out;
 555                /* Mark unused entries in inode bitmap used */
 556                bh = bclean(handle, sb, block);
 557                if (IS_ERR(bh)) {
 558                        err = PTR_ERR(bh);
 559                        goto out;
 560                }
 561
 562                ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 563                                     sb->s_blocksize * 8, bh->b_data);
 564                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 565                if (err)
 566                        goto out;
 567                brelse(bh);
 568        }
 569        bh = NULL;
 570
 571        /* Mark group tables in block bitmap */
 572        for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 573                count = group_table_count[j];
 574                start = (&group_data[0].block_bitmap)[j];
 575                block = start;
 576                for (i = 1; i < flex_gd->count; i++) {
 577                        block += group_table_count[j];
 578                        if (block == (&group_data[i].block_bitmap)[j]) {
 579                                count += group_table_count[j];
 580                                continue;
 581                        }
 582                        err = set_flexbg_block_bitmap(sb, handle,
 583                                                flex_gd, start, count);
 584                        if (err)
 585                                goto out;
 586                        count = group_table_count[j];
 587                        start = group_data[i].block_bitmap;
 588                        block = start;
 589                }
 590
 591                if (count) {
 592                        err = set_flexbg_block_bitmap(sb, handle,
 593                                                flex_gd, start, count);
 594                        if (err)
 595                                goto out;
 596                }
 597        }
 598
 599out:
 600        brelse(bh);
 601        err2 = ext4_journal_stop(handle);
 602        if (err2 && !err)
 603                err = err2;
 604
 605        return err;
 606}
 607
 608/*
 609 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 610 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 611 * calling this for the first time.  In a sparse filesystem it will be the
 612 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 613 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 614 */
 615static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 616                                  unsigned *five, unsigned *seven)
 617{
 618        unsigned *min = three;
 619        int mult = 3;
 620        unsigned ret;
 621
 622        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 623                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 624                ret = *min;
 625                *min += 1;
 626                return ret;
 627        }
 628
 629        if (*five < *min) {
 630                min = five;
 631                mult = 5;
 632        }
 633        if (*seven < *min) {
 634                min = seven;
 635                mult = 7;
 636        }
 637
 638        ret = *min;
 639        *min *= mult;
 640
 641        return ret;
 642}
 643
 644/*
 645 * Check that all of the backup GDT blocks are held in the primary GDT block.
 646 * It is assumed that they are stored in group order.  Returns the number of
 647 * groups in current filesystem that have BACKUPS, or -ve error code.
 648 */
 649static int verify_reserved_gdb(struct super_block *sb,
 650                               ext4_group_t end,
 651                               struct buffer_head *primary)
 652{
 653        const ext4_fsblk_t blk = primary->b_blocknr;
 654        unsigned three = 1;
 655        unsigned five = 5;
 656        unsigned seven = 7;
 657        unsigned grp;
 658        __le32 *p = (__le32 *)primary->b_data;
 659        int gdbackups = 0;
 660
 661        while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 662                if (le32_to_cpu(*p++) !=
 663                    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 664                        ext4_warning(sb, "reserved GDT %llu"
 665                                     " missing grp %d (%llu)",
 666                                     blk, grp,
 667                                     grp *
 668                                     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 669                                     blk);
 670                        return -EINVAL;
 671                }
 672                if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 673                        return -EFBIG;
 674        }
 675
 676        return gdbackups;
 677}
 678
 679/*
 680 * Called when we need to bring a reserved group descriptor table block into
 681 * use from the resize inode.  The primary copy of the new GDT block currently
 682 * is an indirect block (under the double indirect block in the resize inode).
 683 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 684 * block, in group order.  Even though we know all the block numbers we need,
 685 * we check to ensure that the resize inode has actually reserved these blocks.
 686 *
 687 * Don't need to update the block bitmaps because the blocks are still in use.
 688 *
 689 * We get all of the error cases out of the way, so that we are sure to not
 690 * fail once we start modifying the data on disk, because JBD has no rollback.
 691 */
 692static int add_new_gdb(handle_t *handle, struct inode *inode,
 693                       ext4_group_t group)
 694{
 695        struct super_block *sb = inode->i_sb;
 696        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 697        unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 698        ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 699        struct buffer_head **o_group_desc, **n_group_desc;
 700        struct buffer_head *dind;
 701        struct buffer_head *gdb_bh;
 702        int gdbackups;
 703        struct ext4_iloc iloc;
 704        __le32 *data;
 705        int err;
 706
 707        if (test_opt(sb, DEBUG))
 708                printk(KERN_DEBUG
 709                       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 710                       gdb_num);
 711
 712        /*
 713         * If we are not using the primary superblock/GDT copy don't resize,
 714         * because the user tools have no way of handling this.  Probably a
 715         * bad time to do it anyways.
 716         */
 717        if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 718            le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 719                ext4_warning(sb, "won't resize using backup superblock at %llu",
 720                        (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 721                return -EPERM;
 722        }
 723
 724        gdb_bh = sb_bread(sb, gdblock);
 725        if (!gdb_bh)
 726                return -EIO;
 727
 728        gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 729        if (gdbackups < 0) {
 730                err = gdbackups;
 731                goto exit_bh;
 732        }
 733
 734        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 735        dind = sb_bread(sb, le32_to_cpu(*data));
 736        if (!dind) {
 737                err = -EIO;
 738                goto exit_bh;
 739        }
 740
 741        data = (__le32 *)dind->b_data;
 742        if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 743                ext4_warning(sb, "new group %u GDT block %llu not reserved",
 744                             group, gdblock);
 745                err = -EINVAL;
 746                goto exit_dind;
 747        }
 748
 749        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 750        if (unlikely(err))
 751                goto exit_dind;
 752
 753        err = ext4_journal_get_write_access(handle, gdb_bh);
 754        if (unlikely(err))
 755                goto exit_sbh;
 756
 757        err = ext4_journal_get_write_access(handle, dind);
 758        if (unlikely(err))
 759                ext4_std_error(sb, err);
 760
 761        /* ext4_reserve_inode_write() gets a reference on the iloc */
 762        err = ext4_reserve_inode_write(handle, inode, &iloc);
 763        if (unlikely(err))
 764                goto exit_dindj;
 765
 766        n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 767                                     sizeof(struct buffer_head *),
 768                                     GFP_NOFS);
 769        if (!n_group_desc) {
 770                err = -ENOMEM;
 771                ext4_warning(sb, "not enough memory for %lu groups",
 772                             gdb_num + 1);
 773                goto exit_inode;
 774        }
 775
 776        /*
 777         * Finally, we have all of the possible failures behind us...
 778         *
 779         * Remove new GDT block from inode double-indirect block and clear out
 780         * the new GDT block for use (which also "frees" the backup GDT blocks
 781         * from the reserved inode).  We don't need to change the bitmaps for
 782         * these blocks, because they are marked as in-use from being in the
 783         * reserved inode, and will become GDT blocks (primary and backup).
 784         */
 785        data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 786        err = ext4_handle_dirty_metadata(handle, NULL, dind);
 787        if (unlikely(err)) {
 788                ext4_std_error(sb, err);
 789                goto exit_inode;
 790        }
 791        inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 792        ext4_mark_iloc_dirty(handle, inode, &iloc);
 793        memset(gdb_bh->b_data, 0, sb->s_blocksize);
 794        err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 795        if (unlikely(err)) {
 796                ext4_std_error(sb, err);
 797                goto exit_inode;
 798        }
 799        brelse(dind);
 800
 801        o_group_desc = EXT4_SB(sb)->s_group_desc;
 802        memcpy(n_group_desc, o_group_desc,
 803               EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 804        n_group_desc[gdb_num] = gdb_bh;
 805        EXT4_SB(sb)->s_group_desc = n_group_desc;
 806        EXT4_SB(sb)->s_gdb_count++;
 807        ext4_kvfree(o_group_desc);
 808
 809        le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 810        err = ext4_handle_dirty_super(handle, sb);
 811        if (err)
 812                ext4_std_error(sb, err);
 813
 814        return err;
 815
 816exit_inode:
 817        ext4_kvfree(n_group_desc);
 818        /* ext4_handle_release_buffer(handle, iloc.bh); */
 819        brelse(iloc.bh);
 820exit_dindj:
 821        /* ext4_handle_release_buffer(handle, dind); */
 822exit_sbh:
 823        /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
 824exit_dind:
 825        brelse(dind);
 826exit_bh:
 827        brelse(gdb_bh);
 828
 829        ext4_debug("leaving with error %d\n", err);
 830        return err;
 831}
 832
 833/*
 834 * Called when we are adding a new group which has a backup copy of each of
 835 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 836 * We need to add these reserved backup GDT blocks to the resize inode, so
 837 * that they are kept for future resizing and not allocated to files.
 838 *
 839 * Each reserved backup GDT block will go into a different indirect block.
 840 * The indirect blocks are actually the primary reserved GDT blocks,
 841 * so we know in advance what their block numbers are.  We only get the
 842 * double-indirect block to verify it is pointing to the primary reserved
 843 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 844 * backup GDT blocks are stored in their reserved primary GDT block.
 845 */
 846static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 847                              ext4_group_t group)
 848{
 849        struct super_block *sb = inode->i_sb;
 850        int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 851        struct buffer_head **primary;
 852        struct buffer_head *dind;
 853        struct ext4_iloc iloc;
 854        ext4_fsblk_t blk;
 855        __le32 *data, *end;
 856        int gdbackups = 0;
 857        int res, i;
 858        int err;
 859
 860        primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 861        if (!primary)
 862                return -ENOMEM;
 863
 864        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 865        dind = sb_bread(sb, le32_to_cpu(*data));
 866        if (!dind) {
 867                err = -EIO;
 868                goto exit_free;
 869        }
 870
 871        blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 872        data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 873                                         EXT4_ADDR_PER_BLOCK(sb));
 874        end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 875
 876        /* Get each reserved primary GDT block and verify it holds backups */
 877        for (res = 0; res < reserved_gdb; res++, blk++) {
 878                if (le32_to_cpu(*data) != blk) {
 879                        ext4_warning(sb, "reserved block %llu"
 880                                     " not at offset %ld",
 881                                     blk,
 882                                     (long)(data - (__le32 *)dind->b_data));
 883                        err = -EINVAL;
 884                        goto exit_bh;
 885                }
 886                primary[res] = sb_bread(sb, blk);
 887                if (!primary[res]) {
 888                        err = -EIO;
 889                        goto exit_bh;
 890                }
 891                gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 892                if (gdbackups < 0) {
 893                        brelse(primary[res]);
 894                        err = gdbackups;
 895                        goto exit_bh;
 896                }
 897                if (++data >= end)
 898                        data = (__le32 *)dind->b_data;
 899        }
 900
 901        for (i = 0; i < reserved_gdb; i++) {
 902                if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
 903                        /*
 904                        int j;
 905                        for (j = 0; j < i; j++)
 906                                ext4_handle_release_buffer(handle, primary[j]);
 907                         */
 908                        goto exit_bh;
 909                }
 910        }
 911
 912        if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 913                goto exit_bh;
 914
 915        /*
 916         * Finally we can add each of the reserved backup GDT blocks from
 917         * the new group to its reserved primary GDT block.
 918         */
 919        blk = group * EXT4_BLOCKS_PER_GROUP(sb);
 920        for (i = 0; i < reserved_gdb; i++) {
 921                int err2;
 922                data = (__le32 *)primary[i]->b_data;
 923                /* printk("reserving backup %lu[%u] = %lu\n",
 924                       primary[i]->b_blocknr, gdbackups,
 925                       blk + primary[i]->b_blocknr); */
 926                data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 927                err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
 928                if (!err)
 929                        err = err2;
 930        }
 931        inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
 932        ext4_mark_iloc_dirty(handle, inode, &iloc);
 933
 934exit_bh:
 935        while (--res >= 0)
 936                brelse(primary[res]);
 937        brelse(dind);
 938
 939exit_free:
 940        kfree(primary);
 941
 942        return err;
 943}
 944
 945/*
 946 * Update the backup copies of the ext4 metadata.  These don't need to be part
 947 * of the main resize transaction, because e2fsck will re-write them if there
 948 * is a problem (basically only OOM will cause a problem).  However, we
 949 * _should_ update the backups if possible, in case the primary gets trashed
 950 * for some reason and we need to run e2fsck from a backup superblock.  The
 951 * important part is that the new block and inode counts are in the backup
 952 * superblocks, and the location of the new group metadata in the GDT backups.
 953 *
 954 * We do not need take the s_resize_lock for this, because these
 955 * blocks are not otherwise touched by the filesystem code when it is
 956 * mounted.  We don't need to worry about last changing from
 957 * sbi->s_groups_count, because the worst that can happen is that we
 958 * do not copy the full number of backups at this time.  The resize
 959 * which changed s_groups_count will backup again.
 960 */
 961static void update_backups(struct super_block *sb,
 962                           int blk_off, char *data, int size)
 963{
 964        struct ext4_sb_info *sbi = EXT4_SB(sb);
 965        const ext4_group_t last = sbi->s_groups_count;
 966        const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
 967        unsigned three = 1;
 968        unsigned five = 5;
 969        unsigned seven = 7;
 970        ext4_group_t group;
 971        int rest = sb->s_blocksize - size;
 972        handle_t *handle;
 973        int err = 0, err2;
 974
 975        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 976        if (IS_ERR(handle)) {
 977                group = 1;
 978                err = PTR_ERR(handle);
 979                goto exit_err;
 980        }
 981
 982        ext4_superblock_csum_set(sb, (struct ext4_super_block *)data);
 983
 984        while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
 985                struct buffer_head *bh;
 986
 987                /* Out of journal space, and can't get more - abort - so sad */
 988                if (ext4_handle_valid(handle) &&
 989                    handle->h_buffer_credits == 0 &&
 990                    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
 991                    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
 992                        break;
 993
 994                bh = sb_getblk(sb, group * bpg + blk_off);
 995                if (!bh) {
 996                        err = -EIO;
 997                        break;
 998                }
 999                ext4_debug("update metadata backup %#04lx\n",
1000                          (unsigned long)bh->b_blocknr);
1001                if ((err = ext4_journal_get_write_access(handle, bh)))
1002                        break;
1003                lock_buffer(bh);
1004                memcpy(bh->b_data, data, size);
1005                if (rest)
1006                        memset(bh->b_data + size, 0, rest);
1007                set_buffer_uptodate(bh);
1008                unlock_buffer(bh);
1009                err = ext4_handle_dirty_metadata(handle, NULL, bh);
1010                if (unlikely(err))
1011                        ext4_std_error(sb, err);
1012                brelse(bh);
1013        }
1014        if ((err2 = ext4_journal_stop(handle)) && !err)
1015                err = err2;
1016
1017        /*
1018         * Ugh! Need to have e2fsck write the backup copies.  It is too
1019         * late to revert the resize, we shouldn't fail just because of
1020         * the backup copies (they are only needed in case of corruption).
1021         *
1022         * However, if we got here we have a journal problem too, so we
1023         * can't really start a transaction to mark the superblock.
1024         * Chicken out and just set the flag on the hope it will be written
1025         * to disk, and if not - we will simply wait until next fsck.
1026         */
1027exit_err:
1028        if (err) {
1029                ext4_warning(sb, "can't update backup for group %u (err %d), "
1030                             "forcing fsck on next reboot", group, err);
1031                sbi->s_mount_state &= ~EXT4_VALID_FS;
1032                sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1033                mark_buffer_dirty(sbi->s_sbh);
1034        }
1035}
1036
1037/*
1038 * ext4_add_new_descs() adds @count group descriptor of groups
1039 * starting at @group
1040 *
1041 * @handle: journal handle
1042 * @sb: super block
1043 * @group: the group no. of the first group desc to be added
1044 * @resize_inode: the resize inode
1045 * @count: number of group descriptors to be added
1046 */
1047static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1048                              ext4_group_t group, struct inode *resize_inode,
1049                              ext4_group_t count)
1050{
1051        struct ext4_sb_info *sbi = EXT4_SB(sb);
1052        struct ext4_super_block *es = sbi->s_es;
1053        struct buffer_head *gdb_bh;
1054        int i, gdb_off, gdb_num, err = 0;
1055
1056        for (i = 0; i < count; i++, group++) {
1057                int reserved_gdb = ext4_bg_has_super(sb, group) ?
1058                        le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1059
1060                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1061                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1062
1063                /*
1064                 * We will only either add reserved group blocks to a backup group
1065                 * or remove reserved blocks for the first group in a new group block.
1066                 * Doing both would be mean more complex code, and sane people don't
1067                 * use non-sparse filesystems anymore.  This is already checked above.
1068                 */
1069                if (gdb_off) {
1070                        gdb_bh = sbi->s_group_desc[gdb_num];
1071                        err = ext4_journal_get_write_access(handle, gdb_bh);
1072
1073                        if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1074                                err = reserve_backup_gdb(handle, resize_inode, group);
1075                } else
1076                        err = add_new_gdb(handle, resize_inode, group);
1077                if (err)
1078                        break;
1079        }
1080        return err;
1081}
1082
1083static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1084{
1085        struct buffer_head *bh = sb_getblk(sb, block);
1086        if (!bh)
1087                return NULL;
1088
1089        if (bitmap_uptodate(bh))
1090                return bh;
1091
1092        lock_buffer(bh);
1093        if (bh_submit_read(bh) < 0) {
1094                unlock_buffer(bh);
1095                brelse(bh);
1096                return NULL;
1097        }
1098        unlock_buffer(bh);
1099
1100        return bh;
1101}
1102
1103static int ext4_set_bitmap_checksums(struct super_block *sb,
1104                                     ext4_group_t group,
1105                                     struct ext4_group_desc *gdp,
1106                                     struct ext4_new_group_data *group_data)
1107{
1108        struct buffer_head *bh;
1109
1110        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1111                                        EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1112                return 0;
1113
1114        bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1115        if (!bh)
1116                return -EIO;
1117        ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1118                                   EXT4_INODES_PER_GROUP(sb) / 8);
1119        brelse(bh);
1120
1121        bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1122        if (!bh)
1123                return -EIO;
1124        ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1125        brelse(bh);
1126
1127        return 0;
1128}
1129
1130/*
1131 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1132 */
1133static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1134                                struct ext4_new_flex_group_data *flex_gd)
1135{
1136        struct ext4_new_group_data      *group_data = flex_gd->groups;
1137        struct ext4_group_desc          *gdp;
1138        struct ext4_sb_info             *sbi = EXT4_SB(sb);
1139        struct buffer_head              *gdb_bh;
1140        ext4_group_t                    group;
1141        __u16                           *bg_flags = flex_gd->bg_flags;
1142        int                             i, gdb_off, gdb_num, err = 0;
1143        
1144
1145        for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1146                group = group_data->group;
1147
1148                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1149                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1150
1151                /*
1152                 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1153                 */
1154                gdb_bh = sbi->s_group_desc[gdb_num];
1155                /* Update group descriptor block for new group */
1156                gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1157                                                 gdb_off * EXT4_DESC_SIZE(sb));
1158
1159                memset(gdp, 0, EXT4_DESC_SIZE(sb));
1160                ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1161                ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1162                err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1163                if (err) {
1164                        ext4_std_error(sb, err);
1165                        break;
1166                }
1167
1168                ext4_inode_table_set(sb, gdp, group_data->inode_table);
1169                ext4_free_group_clusters_set(sb, gdp,
1170                                             EXT4_B2C(sbi, group_data->free_blocks_count));
1171                ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1172                gdp->bg_flags = cpu_to_le16(*bg_flags);
1173                ext4_group_desc_csum_set(sb, group, gdp);
1174
1175                err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1176                if (unlikely(err)) {
1177                        ext4_std_error(sb, err);
1178                        break;
1179                }
1180
1181                /*
1182                 * We can allocate memory for mb_alloc based on the new group
1183                 * descriptor
1184                 */
1185                err = ext4_mb_add_groupinfo(sb, group, gdp);
1186                if (err)
1187                        break;
1188        }
1189        return err;
1190}
1191
1192/*
1193 * ext4_update_super() updates the super block so that the newly added
1194 * groups can be seen by the filesystem.
1195 *
1196 * @sb: super block
1197 * @flex_gd: new added groups
1198 */
1199static void ext4_update_super(struct super_block *sb,
1200                             struct ext4_new_flex_group_data *flex_gd)
1201{
1202        ext4_fsblk_t blocks_count = 0;
1203        ext4_fsblk_t free_blocks = 0;
1204        ext4_fsblk_t reserved_blocks = 0;
1205        struct ext4_new_group_data *group_data = flex_gd->groups;
1206        struct ext4_sb_info *sbi = EXT4_SB(sb);
1207        struct ext4_super_block *es = sbi->s_es;
1208        int i;
1209
1210        BUG_ON(flex_gd->count == 0 || group_data == NULL);
1211        /*
1212         * Make the new blocks and inodes valid next.  We do this before
1213         * increasing the group count so that once the group is enabled,
1214         * all of its blocks and inodes are already valid.
1215         *
1216         * We always allocate group-by-group, then block-by-block or
1217         * inode-by-inode within a group, so enabling these
1218         * blocks/inodes before the group is live won't actually let us
1219         * allocate the new space yet.
1220         */
1221        for (i = 0; i < flex_gd->count; i++) {
1222                blocks_count += group_data[i].blocks_count;
1223                free_blocks += group_data[i].free_blocks_count;
1224        }
1225
1226        reserved_blocks = ext4_r_blocks_count(es) * 100;
1227        do_div(reserved_blocks, ext4_blocks_count(es));
1228        reserved_blocks *= blocks_count;
1229        do_div(reserved_blocks, 100);
1230
1231        ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1232        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1233        le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1234                     flex_gd->count);
1235        le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1236                     flex_gd->count);
1237
1238        /*
1239         * We need to protect s_groups_count against other CPUs seeing
1240         * inconsistent state in the superblock.
1241         *
1242         * The precise rules we use are:
1243         *
1244         * * Writers must perform a smp_wmb() after updating all
1245         *   dependent data and before modifying the groups count
1246         *
1247         * * Readers must perform an smp_rmb() after reading the groups
1248         *   count and before reading any dependent data.
1249         *
1250         * NB. These rules can be relaxed when checking the group count
1251         * while freeing data, as we can only allocate from a block
1252         * group after serialising against the group count, and we can
1253         * only then free after serialising in turn against that
1254         * allocation.
1255         */
1256        smp_wmb();
1257
1258        /* Update the global fs size fields */
1259        sbi->s_groups_count += flex_gd->count;
1260
1261        /* Update the reserved block counts only once the new group is
1262         * active. */
1263        ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1264                                reserved_blocks);
1265
1266        /* Update the free space counts */
1267        percpu_counter_add(&sbi->s_freeclusters_counter,
1268                           EXT4_B2C(sbi, free_blocks));
1269        percpu_counter_add(&sbi->s_freeinodes_counter,
1270                           EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1271
1272        if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1273                                      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1274            sbi->s_log_groups_per_flex) {
1275                ext4_group_t flex_group;
1276                flex_group = ext4_flex_group(sbi, group_data[0].group);
1277                atomic_add(EXT4_B2C(sbi, free_blocks),
1278                           &sbi->s_flex_groups[flex_group].free_clusters);
1279                atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1280                           &sbi->s_flex_groups[flex_group].free_inodes);
1281        }
1282
1283        /*
1284         * Update the fs overhead information
1285         */
1286        ext4_calculate_overhead(sb);
1287
1288        if (test_opt(sb, DEBUG))
1289                printk(KERN_DEBUG "EXT4-fs: added group %u:"
1290                       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1291                       blocks_count, free_blocks, reserved_blocks);
1292}
1293
1294/* Add a flex group to an fs. Ensure we handle all possible error conditions
1295 * _before_ we start modifying the filesystem, because we cannot abort the
1296 * transaction and not have it write the data to disk.
1297 */
1298static int ext4_flex_group_add(struct super_block *sb,
1299                               struct inode *resize_inode,
1300                               struct ext4_new_flex_group_data *flex_gd)
1301{
1302        struct ext4_sb_info *sbi = EXT4_SB(sb);
1303        struct ext4_super_block *es = sbi->s_es;
1304        ext4_fsblk_t o_blocks_count;
1305        ext4_grpblk_t last;
1306        ext4_group_t group;
1307        handle_t *handle;
1308        unsigned reserved_gdb;
1309        int err = 0, err2 = 0, credit;
1310
1311        BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1312
1313        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1314        o_blocks_count = ext4_blocks_count(es);
1315        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1316        BUG_ON(last);
1317
1318        err = setup_new_flex_group_blocks(sb, flex_gd);
1319        if (err)
1320                goto exit;
1321        /*
1322         * We will always be modifying at least the superblock and  GDT
1323         * block.  If we are adding a group past the last current GDT block,
1324         * we will also modify the inode and the dindirect block.  If we
1325         * are adding a group with superblock/GDT backups  we will also
1326         * modify each of the reserved GDT dindirect blocks.
1327         */
1328        credit = flex_gd->count * 4 + reserved_gdb;
1329        handle = ext4_journal_start_sb(sb, credit);
1330        if (IS_ERR(handle)) {
1331                err = PTR_ERR(handle);
1332                goto exit;
1333        }
1334
1335        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1336        if (err)
1337                goto exit_journal;
1338
1339        group = flex_gd->groups[0].group;
1340        BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1341        err = ext4_add_new_descs(handle, sb, group,
1342                                resize_inode, flex_gd->count);
1343        if (err)
1344                goto exit_journal;
1345
1346        err = ext4_setup_new_descs(handle, sb, flex_gd);
1347        if (err)
1348                goto exit_journal;
1349
1350        ext4_update_super(sb, flex_gd);
1351
1352        err = ext4_handle_dirty_super(handle, sb);
1353
1354exit_journal:
1355        err2 = ext4_journal_stop(handle);
1356        if (!err)
1357                err = err2;
1358
1359        if (!err) {
1360                int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1361                int gdb_num_end = ((group + flex_gd->count - 1) /
1362                                   EXT4_DESC_PER_BLOCK(sb));
1363
1364                update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1365                               sizeof(struct ext4_super_block));
1366                for (; gdb_num <= gdb_num_end; gdb_num++) {
1367                        struct buffer_head *gdb_bh;
1368
1369                        gdb_bh = sbi->s_group_desc[gdb_num];
1370                        update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1371                                       gdb_bh->b_size);
1372                }
1373        }
1374exit:
1375        return err;
1376}
1377
1378static int ext4_setup_next_flex_gd(struct super_block *sb,
1379                                    struct ext4_new_flex_group_data *flex_gd,
1380                                    ext4_fsblk_t n_blocks_count,
1381                                    unsigned long flexbg_size)
1382{
1383        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1384        struct ext4_new_group_data *group_data = flex_gd->groups;
1385        ext4_fsblk_t o_blocks_count;
1386        ext4_group_t n_group;
1387        ext4_group_t group;
1388        ext4_group_t last_group;
1389        ext4_grpblk_t last;
1390        ext4_grpblk_t blocks_per_group;
1391        unsigned long i;
1392
1393        blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1394
1395        o_blocks_count = ext4_blocks_count(es);
1396
1397        if (o_blocks_count == n_blocks_count)
1398                return 0;
1399
1400        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1401        BUG_ON(last);
1402        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1403
1404        last_group = group | (flexbg_size - 1);
1405        if (last_group > n_group)
1406                last_group = n_group;
1407
1408        flex_gd->count = last_group - group + 1;
1409
1410        for (i = 0; i < flex_gd->count; i++) {
1411                int overhead;
1412
1413                group_data[i].group = group + i;
1414                group_data[i].blocks_count = blocks_per_group;
1415                overhead = ext4_bg_has_super(sb, group + i) ?
1416                           (1 + ext4_bg_num_gdb(sb, group + i) +
1417                            le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
1418                group_data[i].free_blocks_count = blocks_per_group - overhead;
1419                if (ext4_has_group_desc_csum(sb))
1420                        flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1421                                               EXT4_BG_INODE_UNINIT;
1422                else
1423                        flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1424        }
1425
1426        if (last_group == n_group && ext4_has_group_desc_csum(sb))
1427                /* We need to initialize block bitmap of last group. */
1428                flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1429
1430        if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1431                group_data[i - 1].blocks_count = last + 1;
1432                group_data[i - 1].free_blocks_count -= blocks_per_group-
1433                                        last - 1;
1434        }
1435
1436        return 1;
1437}
1438
1439/* Add group descriptor data to an existing or new group descriptor block.
1440 * Ensure we handle all possible error conditions _before_ we start modifying
1441 * the filesystem, because we cannot abort the transaction and not have it
1442 * write the data to disk.
1443 *
1444 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1445 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1446 *
1447 * We only need to hold the superblock lock while we are actually adding
1448 * in the new group's counts to the superblock.  Prior to that we have
1449 * not really "added" the group at all.  We re-check that we are still
1450 * adding in the last group in case things have changed since verifying.
1451 */
1452int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1453{
1454        struct ext4_new_flex_group_data flex_gd;
1455        struct ext4_sb_info *sbi = EXT4_SB(sb);
1456        struct ext4_super_block *es = sbi->s_es;
1457        int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1458                le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1459        struct inode *inode = NULL;
1460        int gdb_off, gdb_num;
1461        int err;
1462        __u16 bg_flags = 0;
1463
1464        gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1465        gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1466
1467        if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1468                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1469                ext4_warning(sb, "Can't resize non-sparse filesystem further");
1470                return -EPERM;
1471        }
1472
1473        if (ext4_blocks_count(es) + input->blocks_count <
1474            ext4_blocks_count(es)) {
1475                ext4_warning(sb, "blocks_count overflow");
1476                return -EINVAL;
1477        }
1478
1479        if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1480            le32_to_cpu(es->s_inodes_count)) {
1481                ext4_warning(sb, "inodes_count overflow");
1482                return -EINVAL;
1483        }
1484
1485        if (reserved_gdb || gdb_off == 0) {
1486                if (!EXT4_HAS_COMPAT_FEATURE(sb,
1487                                             EXT4_FEATURE_COMPAT_RESIZE_INODE)
1488                    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1489                        ext4_warning(sb,
1490                                     "No reserved GDT blocks, can't resize");
1491                        return -EPERM;
1492                }
1493                inode = ext4_iget(sb, EXT4_RESIZE_INO);
1494                if (IS_ERR(inode)) {
1495                        ext4_warning(sb, "Error opening resize inode");
1496                        return PTR_ERR(inode);
1497                }
1498        }
1499
1500
1501        err = verify_group_input(sb, input);
1502        if (err)
1503                goto out;
1504
1505        flex_gd.count = 1;
1506        flex_gd.groups = input;
1507        flex_gd.bg_flags = &bg_flags;
1508        err = ext4_flex_group_add(sb, inode, &flex_gd);
1509out:
1510        iput(inode);
1511        return err;
1512} /* ext4_group_add */
1513
1514/*
1515 * extend a group without checking assuming that checking has been done.
1516 */
1517static int ext4_group_extend_no_check(struct super_block *sb,
1518                                      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1519{
1520        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1521        handle_t *handle;
1522        int err = 0, err2;
1523
1524        /* We will update the superblock, one block bitmap, and
1525         * one group descriptor via ext4_group_add_blocks().
1526         */
1527        handle = ext4_journal_start_sb(sb, 3);
1528        if (IS_ERR(handle)) {
1529                err = PTR_ERR(handle);
1530                ext4_warning(sb, "error %d on journal start", err);
1531                return err;
1532        }
1533
1534        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1535        if (err) {
1536                ext4_warning(sb, "error %d on journal write access", err);
1537                goto errout;
1538        }
1539
1540        ext4_blocks_count_set(es, o_blocks_count + add);
1541        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1542        ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1543                   o_blocks_count + add);
1544        /* We add the blocks to the bitmap and set the group need init bit */
1545        err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1546        if (err)
1547                goto errout;
1548        ext4_handle_dirty_super(handle, sb);
1549        ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1550                   o_blocks_count + add);
1551errout:
1552        err2 = ext4_journal_stop(handle);
1553        if (err2 && !err)
1554                err = err2;
1555
1556        if (!err) {
1557                if (test_opt(sb, DEBUG))
1558                        printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1559                               "blocks\n", ext4_blocks_count(es));
1560                update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1561                               sizeof(struct ext4_super_block));
1562        }
1563        return err;
1564}
1565
1566/*
1567 * Extend the filesystem to the new number of blocks specified.  This entry
1568 * point is only used to extend the current filesystem to the end of the last
1569 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1570 * for emergencies (because it has no dependencies on reserved blocks).
1571 *
1572 * If we _really_ wanted, we could use default values to call ext4_group_add()
1573 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1574 * GDT blocks are reserved to grow to the desired size.
1575 */
1576int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1577                      ext4_fsblk_t n_blocks_count)
1578{
1579        ext4_fsblk_t o_blocks_count;
1580        ext4_grpblk_t last;
1581        ext4_grpblk_t add;
1582        struct buffer_head *bh;
1583        int err;
1584        ext4_group_t group;
1585
1586        o_blocks_count = ext4_blocks_count(es);
1587
1588        if (test_opt(sb, DEBUG))
1589                ext4_msg(sb, KERN_DEBUG,
1590                         "extending last group from %llu to %llu blocks",
1591                         o_blocks_count, n_blocks_count);
1592
1593        if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1594                return 0;
1595
1596        if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1597                ext4_msg(sb, KERN_ERR,
1598                         "filesystem too large to resize to %llu blocks safely",
1599                         n_blocks_count);
1600                if (sizeof(sector_t) < 8)
1601                        ext4_warning(sb, "CONFIG_LBDAF not enabled");
1602                return -EINVAL;
1603        }
1604
1605        if (n_blocks_count < o_blocks_count) {
1606                ext4_warning(sb, "can't shrink FS - resize aborted");
1607                return -EINVAL;
1608        }
1609
1610        /* Handle the remaining blocks in the last group only. */
1611        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1612
1613        if (last == 0) {
1614                ext4_warning(sb, "need to use ext2online to resize further");
1615                return -EPERM;
1616        }
1617
1618        add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1619
1620        if (o_blocks_count + add < o_blocks_count) {
1621                ext4_warning(sb, "blocks_count overflow");
1622                return -EINVAL;
1623        }
1624
1625        if (o_blocks_count + add > n_blocks_count)
1626                add = n_blocks_count - o_blocks_count;
1627
1628        if (o_blocks_count + add < n_blocks_count)
1629                ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1630                             o_blocks_count + add, add);
1631
1632        /* See if the device is actually as big as what was requested */
1633        bh = sb_bread(sb, o_blocks_count + add - 1);
1634        if (!bh) {
1635                ext4_warning(sb, "can't read last block, resize aborted");
1636                return -ENOSPC;
1637        }
1638        brelse(bh);
1639
1640        err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1641        return err;
1642} /* ext4_group_extend */
1643
1644/*
1645 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1646 *
1647 * @sb: super block of the fs to be resized
1648 * @n_blocks_count: the number of blocks resides in the resized fs
1649 */
1650int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1651{
1652        struct ext4_new_flex_group_data *flex_gd = NULL;
1653        struct ext4_sb_info *sbi = EXT4_SB(sb);
1654        struct ext4_super_block *es = sbi->s_es;
1655        struct buffer_head *bh;
1656        struct inode *resize_inode;
1657        ext4_fsblk_t o_blocks_count;
1658        ext4_group_t o_group;
1659        ext4_group_t n_group;
1660        ext4_grpblk_t offset, add;
1661        unsigned long n_desc_blocks;
1662        unsigned long o_desc_blocks;
1663        unsigned long desc_blocks;
1664        int err = 0, flexbg_size = 1;
1665
1666        o_blocks_count = ext4_blocks_count(es);
1667
1668        if (test_opt(sb, DEBUG))
1669                ext4_msg(sb, KERN_DEBUG, "resizing filesystem from %llu "
1670                       "to %llu blocks", o_blocks_count, n_blocks_count);
1671
1672        if (n_blocks_count < o_blocks_count) {
1673                /* On-line shrinking not supported */
1674                ext4_warning(sb, "can't shrink FS - resize aborted");
1675                return -EINVAL;
1676        }
1677
1678        if (n_blocks_count == o_blocks_count)
1679                /* Nothing need to do */
1680                return 0;
1681
1682        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
1683        ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1684
1685        n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
1686                        EXT4_DESC_PER_BLOCK(sb);
1687        o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1688                        EXT4_DESC_PER_BLOCK(sb);
1689        desc_blocks = n_desc_blocks - o_desc_blocks;
1690
1691        if (desc_blocks &&
1692            (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
1693             le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
1694                ext4_warning(sb, "No reserved GDT blocks, can't resize");
1695                return -EPERM;
1696        }
1697
1698        resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1699        if (IS_ERR(resize_inode)) {
1700                ext4_warning(sb, "Error opening resize inode");
1701                return PTR_ERR(resize_inode);
1702        }
1703
1704        /* See if the device is actually as big as what was requested */
1705        bh = sb_bread(sb, n_blocks_count - 1);
1706        if (!bh) {
1707                ext4_warning(sb, "can't read last block, resize aborted");
1708                return -ENOSPC;
1709        }
1710        brelse(bh);
1711
1712        /* extend the last group */
1713        if (n_group == o_group)
1714                add = n_blocks_count - o_blocks_count;
1715        else
1716                add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1717        if (add > 0) {
1718                err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1719                if (err)
1720                        goto out;
1721        }
1722
1723        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1724            es->s_log_groups_per_flex)
1725                flexbg_size = 1 << es->s_log_groups_per_flex;
1726
1727        o_blocks_count = ext4_blocks_count(es);
1728        if (o_blocks_count == n_blocks_count)
1729                goto out;
1730
1731        flex_gd = alloc_flex_gd(flexbg_size);
1732        if (flex_gd == NULL) {
1733                err = -ENOMEM;
1734                goto out;
1735        }
1736
1737        /* Add flex groups. Note that a regular group is a
1738         * flex group with 1 group.
1739         */
1740        while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1741                                              flexbg_size)) {
1742                if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1743                        break;
1744                err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1745                if (unlikely(err))
1746                        break;
1747        }
1748
1749out:
1750        if (flex_gd)
1751                free_flex_gd(flex_gd);
1752
1753        iput(resize_inode);
1754        if (test_opt(sb, DEBUG))
1755                ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
1756                       "upto %llu blocks", o_blocks_count, n_blocks_count);
1757        return err;
1758}
1759
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