linux/fs/ext4/resize.c
<<
>>
Prefs
   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 */
 204static void ext4_alloc_group_tables(struct super_block *sb,
 205                                struct ext4_new_flex_group_data *flex_gd,
 206                                int flexbg_size)
 207{
 208        struct ext4_new_group_data *group_data = flex_gd->groups;
 209        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 210        ext4_fsblk_t start_blk;
 211        ext4_fsblk_t last_blk;
 212        ext4_group_t src_group;
 213        ext4_group_t bb_index = 0;
 214        ext4_group_t ib_index = 0;
 215        ext4_group_t it_index = 0;
 216        ext4_group_t group;
 217        ext4_group_t last_group;
 218        unsigned overhead;
 219
 220        BUG_ON(flex_gd->count == 0 || group_data == NULL);
 221
 222        src_group = group_data[0].group;
 223        last_group  = src_group + flex_gd->count - 1;
 224
 225        BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 226               (last_group & ~(flexbg_size - 1))));
 227next_group:
 228        group = group_data[0].group;
 229        start_blk = ext4_group_first_block_no(sb, src_group);
 230        last_blk = start_blk + group_data[src_group - group].blocks_count;
 231
 232        overhead = ext4_bg_has_super(sb, src_group) ?
 233                   (1 + ext4_bg_num_gdb(sb, src_group) +
 234                    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
 235
 236        start_blk += overhead;
 237
 238        BUG_ON(src_group >= group_data[0].group + flex_gd->count);
 239        /* We collect contiguous blocks as much as possible. */
 240        src_group++;
 241        for (; src_group <= last_group; src_group++)
 242                if (!ext4_bg_has_super(sb, src_group))
 243                        last_blk += group_data[src_group - group].blocks_count;
 244                else
 245                        break;
 246
 247        /* Allocate block bitmaps */
 248        for (; bb_index < flex_gd->count; bb_index++) {
 249                if (start_blk >= last_blk)
 250                        goto next_group;
 251                group_data[bb_index].block_bitmap = start_blk++;
 252                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 253                group -= group_data[0].group;
 254                group_data[group].free_blocks_count--;
 255                if (flexbg_size > 1)
 256                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 257        }
 258
 259        /* Allocate inode bitmaps */
 260        for (; ib_index < flex_gd->count; ib_index++) {
 261                if (start_blk >= last_blk)
 262                        goto next_group;
 263                group_data[ib_index].inode_bitmap = start_blk++;
 264                ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
 265                group -= group_data[0].group;
 266                group_data[group].free_blocks_count--;
 267                if (flexbg_size > 1)
 268                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 269        }
 270
 271        /* Allocate inode tables */
 272        for (; it_index < flex_gd->count; it_index++) {
 273                if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
 274                        goto next_group;
 275                group_data[it_index].inode_table = start_blk;
 276                ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
 277                group -= group_data[0].group;
 278                group_data[group].free_blocks_count -=
 279                                        EXT4_SB(sb)->s_itb_per_group;
 280                if (flexbg_size > 1)
 281                        flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
 282
 283                start_blk += EXT4_SB(sb)->s_itb_per_group;
 284        }
 285
 286        if (test_opt(sb, DEBUG)) {
 287                int i;
 288                group = group_data[0].group;
 289
 290                printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 291                       "%d groups, flexbg size is %d:\n", flex_gd->count,
 292                       flexbg_size);
 293
 294                for (i = 0; i < flex_gd->count; i++) {
 295                        printk(KERN_DEBUG "adding %s group %u: %u "
 296                               "blocks (%d free)\n",
 297                               ext4_bg_has_super(sb, group + i) ? "normal" :
 298                               "no-super", group + i,
 299                               group_data[i].blocks_count,
 300                               group_data[i].free_blocks_count);
 301                }
 302        }
 303}
 304
 305static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 306                                  ext4_fsblk_t blk)
 307{
 308        struct buffer_head *bh;
 309        int err;
 310
 311        bh = sb_getblk(sb, blk);
 312        if (!bh)
 313                return ERR_PTR(-EIO);
 314        if ((err = ext4_journal_get_write_access(handle, bh))) {
 315                brelse(bh);
 316                bh = ERR_PTR(err);
 317        } else {
 318                memset(bh->b_data, 0, sb->s_blocksize);
 319                set_buffer_uptodate(bh);
 320        }
 321
 322        return bh;
 323}
 324
 325/*
 326 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 327 * If that fails, restart the transaction & regain write access for the
 328 * buffer head which is used for block_bitmap modifications.
 329 */
 330static int extend_or_restart_transaction(handle_t *handle, int thresh)
 331{
 332        int err;
 333
 334        if (ext4_handle_has_enough_credits(handle, thresh))
 335                return 0;
 336
 337        err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 338        if (err < 0)
 339                return err;
 340        if (err) {
 341                err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 342                if (err)
 343                        return err;
 344        }
 345
 346        return 0;
 347}
 348
 349/*
 350 * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
 351 *
 352 * Helper function for ext4_setup_new_group_blocks() which set .
 353 *
 354 * @sb: super block
 355 * @handle: journal handle
 356 * @flex_gd: flex group data
 357 */
 358static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 359                        struct ext4_new_flex_group_data *flex_gd,
 360                        ext4_fsblk_t block, ext4_group_t count)
 361{
 362        ext4_group_t count2;
 363
 364        ext4_debug("mark blocks [%llu/%u] used\n", block, count);
 365        for (count2 = count; count > 0; count -= count2, block += count2) {
 366                ext4_fsblk_t start;
 367                struct buffer_head *bh;
 368                ext4_group_t group;
 369                int err;
 370
 371                ext4_get_group_no_and_offset(sb, block, &group, NULL);
 372                start = ext4_group_first_block_no(sb, group);
 373                group -= flex_gd->groups[0].group;
 374
 375                count2 = sb->s_blocksize * 8 - (block - start);
 376                if (count2 > count)
 377                        count2 = count;
 378
 379                if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 380                        BUG_ON(flex_gd->count > 1);
 381                        continue;
 382                }
 383
 384                err = extend_or_restart_transaction(handle, 1);
 385                if (err)
 386                        return err;
 387
 388                bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 389                if (!bh)
 390                        return -EIO;
 391
 392                err = ext4_journal_get_write_access(handle, bh);
 393                if (err)
 394                        return err;
 395                ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
 396                           block - start, count2);
 397                ext4_set_bits(bh->b_data, block - start, count2);
 398
 399                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 400                if (unlikely(err))
 401                        return err;
 402                brelse(bh);
 403        }
 404
 405        return 0;
 406}
 407
 408/*
 409 * Set up the block and inode bitmaps, and the inode table for the new groups.
 410 * This doesn't need to be part of the main transaction, since we are only
 411 * changing blocks outside the actual filesystem.  We still do journaling to
 412 * ensure the recovery is correct in case of a failure just after resize.
 413 * If any part of this fails, we simply abort the resize.
 414 *
 415 * setup_new_flex_group_blocks handles a flex group as follow:
 416 *  1. copy super block and GDT, and initialize group tables if necessary.
 417 *     In this step, we only set bits in blocks bitmaps for blocks taken by
 418 *     super block and GDT.
 419 *  2. allocate group tables in block bitmaps, that is, set bits in block
 420 *     bitmap for blocks taken by group tables.
 421 */
 422static int setup_new_flex_group_blocks(struct super_block *sb,
 423                                struct ext4_new_flex_group_data *flex_gd)
 424{
 425        int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 426        ext4_fsblk_t start;
 427        ext4_fsblk_t block;
 428        struct ext4_sb_info *sbi = EXT4_SB(sb);
 429        struct ext4_super_block *es = sbi->s_es;
 430        struct ext4_new_group_data *group_data = flex_gd->groups;
 431        __u16 *bg_flags = flex_gd->bg_flags;
 432        handle_t *handle;
 433        ext4_group_t group, count;
 434        struct buffer_head *bh = NULL;
 435        int reserved_gdb, i, j, err = 0, err2;
 436
 437        BUG_ON(!flex_gd->count || !group_data ||
 438               group_data[0].group != sbi->s_groups_count);
 439
 440        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 441
 442        /* This transaction may be extended/restarted along the way */
 443        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 444        if (IS_ERR(handle))
 445                return PTR_ERR(handle);
 446
 447        group = group_data[0].group;
 448        for (i = 0; i < flex_gd->count; i++, group++) {
 449                unsigned long gdblocks;
 450
 451                gdblocks = ext4_bg_num_gdb(sb, group);
 452                start = ext4_group_first_block_no(sb, group);
 453
 454                /* Copy all of the GDT blocks into the backup in this group */
 455                for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
 456                        struct buffer_head *gdb;
 457
 458                        ext4_debug("update backup group %#04llx\n", block);
 459                        err = extend_or_restart_transaction(handle, 1);
 460                        if (err)
 461                                goto out;
 462
 463                        gdb = sb_getblk(sb, block);
 464                        if (!gdb) {
 465                                err = -EIO;
 466                                goto out;
 467                        }
 468
 469                        err = ext4_journal_get_write_access(handle, gdb);
 470                        if (err) {
 471                                brelse(gdb);
 472                                goto out;
 473                        }
 474                        memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 475                               gdb->b_size);
 476                        set_buffer_uptodate(gdb);
 477
 478                        err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 479                        if (unlikely(err)) {
 480                                brelse(gdb);
 481                                goto out;
 482                        }
 483                        brelse(gdb);
 484                }
 485
 486                /* Zero out all of the reserved backup group descriptor
 487                 * table blocks
 488                 */
 489                if (ext4_bg_has_super(sb, group)) {
 490                        err = sb_issue_zeroout(sb, gdblocks + start + 1,
 491                                        reserved_gdb, GFP_NOFS);
 492                        if (err)
 493                                goto out;
 494                }
 495
 496                /* Initialize group tables of the grop @group */
 497                if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 498                        goto handle_bb;
 499
 500                /* Zero out all of the inode table blocks */
 501                block = group_data[i].inode_table;
 502                ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 503                           block, sbi->s_itb_per_group);
 504                err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 505                                       GFP_NOFS);
 506                if (err)
 507                        goto out;
 508
 509handle_bb:
 510                if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 511                        goto handle_ib;
 512
 513                /* Initialize block bitmap of the @group */
 514                block = group_data[i].block_bitmap;
 515                err = extend_or_restart_transaction(handle, 1);
 516                if (err)
 517                        goto out;
 518
 519                bh = bclean(handle, sb, block);
 520                if (IS_ERR(bh)) {
 521                        err = PTR_ERR(bh);
 522                        goto out;
 523                }
 524                if (ext4_bg_has_super(sb, group)) {
 525                        ext4_debug("mark backup superblock %#04llx (+0)\n",
 526                                   start);
 527                        ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
 528                                                     1);
 529                }
 530                ext4_mark_bitmap_end(group_data[i].blocks_count,
 531                                     sb->s_blocksize * 8, bh->b_data);
 532                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 533                if (err)
 534                        goto out;
 535                brelse(bh);
 536
 537handle_ib:
 538                if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 539                        continue;
 540
 541                /* Initialize inode bitmap of the @group */
 542                block = group_data[i].inode_bitmap;
 543                err = extend_or_restart_transaction(handle, 1);
 544                if (err)
 545                        goto out;
 546                /* Mark unused entries in inode bitmap used */
 547                bh = bclean(handle, sb, block);
 548                if (IS_ERR(bh)) {
 549                        err = PTR_ERR(bh);
 550                        goto out;
 551                }
 552
 553                ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 554                                     sb->s_blocksize * 8, bh->b_data);
 555                err = ext4_handle_dirty_metadata(handle, NULL, bh);
 556                if (err)
 557                        goto out;
 558                brelse(bh);
 559        }
 560        bh = NULL;
 561
 562        /* Mark group tables in block bitmap */
 563        for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 564                count = group_table_count[j];
 565                start = (&group_data[0].block_bitmap)[j];
 566                block = start;
 567                for (i = 1; i < flex_gd->count; i++) {
 568                        block += group_table_count[j];
 569                        if (block == (&group_data[i].block_bitmap)[j]) {
 570                                count += group_table_count[j];
 571                                continue;
 572                        }
 573                        err = set_flexbg_block_bitmap(sb, handle,
 574                                                flex_gd, start, count);
 575                        if (err)
 576                                goto out;
 577                        count = group_table_count[j];
 578                        start = group_data[i].block_bitmap;
 579                        block = start;
 580                }
 581
 582                if (count) {
 583                        err = set_flexbg_block_bitmap(sb, handle,
 584                                                flex_gd, start, count);
 585                        if (err)
 586                                goto out;
 587                }
 588        }
 589
 590out:
 591        brelse(bh);
 592        err2 = ext4_journal_stop(handle);
 593        if (err2 && !err)
 594                err = err2;
 595
 596        return err;
 597}
 598
 599/*
 600 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 601 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 602 * calling this for the first time.  In a sparse filesystem it will be the
 603 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 604 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 605 */
 606static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 607                                  unsigned *five, unsigned *seven)
 608{
 609        unsigned *min = three;
 610        int mult = 3;
 611        unsigned ret;
 612
 613        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 614                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
 615                ret = *min;
 616                *min += 1;
 617                return ret;
 618        }
 619
 620        if (*five < *min) {
 621                min = five;
 622                mult = 5;
 623        }
 624        if (*seven < *min) {
 625                min = seven;
 626                mult = 7;
 627        }
 628
 629        ret = *min;
 630        *min *= mult;
 631
 632        return ret;
 633}
 634
 635/*
 636 * Check that all of the backup GDT blocks are held in the primary GDT block.
 637 * It is assumed that they are stored in group order.  Returns the number of
 638 * groups in current filesystem that have BACKUPS, or -ve error code.
 639 */
 640static int verify_reserved_gdb(struct super_block *sb,
 641                               ext4_group_t end,
 642                               struct buffer_head *primary)
 643{
 644        const ext4_fsblk_t blk = primary->b_blocknr;
 645        unsigned three = 1;
 646        unsigned five = 5;
 647        unsigned seven = 7;
 648        unsigned grp;
 649        __le32 *p = (__le32 *)primary->b_data;
 650        int gdbackups = 0;
 651
 652        while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 653                if (le32_to_cpu(*p++) !=
 654                    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 655                        ext4_warning(sb, "reserved GDT %llu"
 656                                     " missing grp %d (%llu)",
 657                                     blk, grp,
 658                                     grp *
 659                                     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 660                                     blk);
 661                        return -EINVAL;
 662                }
 663                if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 664                        return -EFBIG;
 665        }
 666
 667        return gdbackups;
 668}
 669
 670/*
 671 * Called when we need to bring a reserved group descriptor table block into
 672 * use from the resize inode.  The primary copy of the new GDT block currently
 673 * is an indirect block (under the double indirect block in the resize inode).
 674 * The new backup GDT blocks will be stored as leaf blocks in this indirect
 675 * block, in group order.  Even though we know all the block numbers we need,
 676 * we check to ensure that the resize inode has actually reserved these blocks.
 677 *
 678 * Don't need to update the block bitmaps because the blocks are still in use.
 679 *
 680 * We get all of the error cases out of the way, so that we are sure to not
 681 * fail once we start modifying the data on disk, because JBD has no rollback.
 682 */
 683static int add_new_gdb(handle_t *handle, struct inode *inode,
 684                       ext4_group_t group)
 685{
 686        struct super_block *sb = inode->i_sb;
 687        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 688        unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 689        ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 690        struct buffer_head **o_group_desc, **n_group_desc;
 691        struct buffer_head *dind;
 692        struct buffer_head *gdb_bh;
 693        int gdbackups;
 694        struct ext4_iloc iloc;
 695        __le32 *data;
 696        int err;
 697
 698        if (test_opt(sb, DEBUG))
 699                printk(KERN_DEBUG
 700                       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 701                       gdb_num);
 702
 703        /*
 704         * If we are not using the primary superblock/GDT copy don't resize,
 705         * because the user tools have no way of handling this.  Probably a
 706         * bad time to do it anyways.
 707         */
 708        if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 709            le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 710                ext4_warning(sb, "won't resize using backup superblock at %llu",
 711                        (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
 712                return -EPERM;
 713        }
 714
 715        gdb_bh = sb_bread(sb, gdblock);
 716        if (!gdb_bh)
 717                return -EIO;
 718
 719        gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 720        if (gdbackups < 0) {
 721                err = gdbackups;
 722                goto exit_bh;
 723        }
 724
 725        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 726        dind = sb_bread(sb, le32_to_cpu(*data));
 727        if (!dind) {
 728                err = -EIO;
 729                goto exit_bh;
 730        }
 731
 732        data = (__le32 *)dind->b_data;
 733        if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 734                ext4_warning(sb, "new group %u GDT block %llu not reserved",
 735                             group, gdblock);
 736                err = -EINVAL;
 737                goto exit_dind;
 738        }
 739
 740        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 741        if (unlikely(err))
 742                goto exit_dind;
 743
 744        err = ext4_journal_get_write_access(handle, gdb_bh);
 745        if (unlikely(err))
 746                goto exit_sbh;
 747
 748        err = ext4_journal_get_write_access(handle, dind);
 749        if (unlikely(err))
 750                ext4_std_error(sb, err);
 751
 752        /* ext4_reserve_inode_write() gets a reference on the iloc */
 753        err = ext4_reserve_inode_write(handle, inode, &iloc);
 754        if (unlikely(err))
 755                goto exit_dindj;
 756
 757        n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 758                                     sizeof(struct buffer_head *),
 759                                     GFP_NOFS);
 760        if (!n_group_desc) {
 761                err = -ENOMEM;
 762                ext4_warning(sb, "not enough memory for %lu groups",
 763                             gdb_num + 1);
 764                goto exit_inode;
 765        }
 766
 767        /*
 768         * Finally, we have all of the possible failures behind us...
 769         *
 770         * Remove new GDT block from inode double-indirect block and clear out
 771         * the new GDT block for use (which also "frees" the backup GDT blocks
 772         * from the reserved inode).  We don't need to change the bitmaps for
 773         * these blocks, because they are marked as in-use from being in the
 774         * reserved inode, and will become GDT blocks (primary and backup).
 775         */
 776        data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 777        err = ext4_handle_dirty_metadata(handle, NULL, dind);
 778        if (unlikely(err)) {
 779                ext4_std_error(sb, err);
 780                goto exit_inode;
 781        }
 782        inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
 783        ext4_mark_iloc_dirty(handle, inode, &iloc);
 784        memset(gdb_bh->b_data, 0, sb->s_blocksize);
 785        err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 786        if (unlikely(err)) {
 787                ext4_std_error(sb, err);
 788                goto exit_inode;
 789        }
 790        brelse(dind);
 791
 792        o_group_desc = EXT4_SB(sb)->s_group_desc;
 793        memcpy(n_group_desc, o_group_desc,
 794               EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 795        n_group_desc[gdb_num] = gdb_bh;
 796        EXT4_SB(sb)->s_group_desc = n_group_desc;
 797        EXT4_SB(sb)->s_gdb_count++;
 798        ext4_kvfree(o_group_desc);
 799
 800        le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 801        err = ext4_handle_dirty_super(handle, sb);
 802        if (err)
 803                ext4_std_error(sb, err);
 804
 805        return err;
 806
 807exit_inode:
 808        ext4_kvfree(n_group_desc);
 809        /* ext4_handle_release_buffer(handle, iloc.bh); */
 810        brelse(iloc.bh);
 811exit_dindj:
 812        /* ext4_handle_release_buffer(handle, dind); */
 813exit_sbh:
 814        /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
 815exit_dind:
 816        brelse(dind);
 817exit_bh:
 818        brelse(gdb_bh);
 819
 820        ext4_debug("leaving with error %d\n", err);
 821        return err;
 822}
 823
 824/*
 825 * Called when we are adding a new group which has a backup copy of each of
 826 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 827 * We need to add these reserved backup GDT blocks to the resize inode, so
 828 * that they are kept for future resizing and not allocated to files.
 829 *
 830 * Each reserved backup GDT block will go into a different indirect block.
 831 * The indirect blocks are actually the primary reserved GDT blocks,
 832 * so we know in advance what their block numbers are.  We only get the
 833 * double-indirect block to verify it is pointing to the primary reserved
 834 * GDT blocks so we don't overwrite a data block by accident.  The reserved
 835 * backup GDT blocks are stored in their reserved primary GDT block.
 836 */
 837static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 838                              ext4_group_t group)
 839{
 840        struct super_block *sb = inode->i_sb;
 841        int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 842        struct buffer_head **primary;
 843        struct buffer_head *dind;
 844        struct ext4_iloc iloc;
 845        ext4_fsblk_t blk;
 846        __le32 *data, *end;
 847        int gdbackups = 0;
 848        int res, i;
 849        int err;
 850
 851        primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
 852        if (!primary)
 853                return -ENOMEM;
 854
 855        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 856        dind = sb_bread(sb, le32_to_cpu(*data));
 857        if (!dind) {
 858                err = -EIO;
 859                goto exit_free;
 860        }
 861
 862        blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 863        data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 864                                         EXT4_ADDR_PER_BLOCK(sb));
 865        end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 866
 867        /* Get each reserved primary GDT block and verify it holds backups */
 868        for (res = 0; res < reserved_gdb; res++, blk++) {
 869                if (le32_to_cpu(*data) != blk) {
 870                        ext4_warning(sb, "reserved block %llu"
 871                                     " not at offset %ld",
 872                                     blk,
 873                                     (long)(data - (__le32 *)dind->b_data));
 874                        err = -EINVAL;
 875                        goto exit_bh;
 876                }
 877                primary[res] = sb_bread(sb, blk);
 878                if (!primary[res]) {
 879                        err = -EIO;
 880                        goto exit_bh;
 881                }
 882                gdbackups = verify_reserved_gdb(sb, group, primary[res]);
 883                if (gdbackups < 0) {
 884                        brelse(primary[res]);
 885                        err = gdbackups;
 886                        goto exit_bh;
 887                }
 888                if (++data >= end)
 889                        data = (__le32 *)dind->b_data;
 890        }
 891
 892        for (i = 0; i < reserved_gdb; i++) {
 893                if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
 894                        /*
 895                        int j;
 896                        for (j = 0; j < i; j++)
 897                                ext4_handle_release_buffer(handle, primary[j]);
 898                         */
 899                        goto exit_bh;
 900                }
 901        }
 902
 903        if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
 904                goto exit_bh;
 905
 906        /*
 907         * Finally we can add each of the reserved backup GDT blocks from
 908         * the new group to its reserved primary GDT block.
 909         */
 910        blk = group * EXT4_BLOCKS_PER_GROUP(sb);
 911        for (i = 0; i < reserved_gdb; i++) {
 912                int err2;
 913                data = (__le32 *)primary[i]->b_data;
 914                /* printk("reserving backup %lu[%u] = %lu\n",
 915                       primary[i]->b_blocknr, gdbackups,
 916                       blk + primary[i]->b_blocknr); */
 917                data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
 918                err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
 919                if (!err)
 920                        err = err2;
 921        }
 922        inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
 923        ext4_mark_iloc_dirty(handle, inode, &iloc);
 924
 925exit_bh:
 926        while (--res >= 0)
 927                brelse(primary[res]);
 928        brelse(dind);
 929
 930exit_free:
 931        kfree(primary);
 932
 933        return err;
 934}
 935
 936/*
 937 * Update the backup copies of the ext4 metadata.  These don't need to be part
 938 * of the main resize transaction, because e2fsck will re-write them if there
 939 * is a problem (basically only OOM will cause a problem).  However, we
 940 * _should_ update the backups if possible, in case the primary gets trashed
 941 * for some reason and we need to run e2fsck from a backup superblock.  The
 942 * important part is that the new block and inode counts are in the backup
 943 * superblocks, and the location of the new group metadata in the GDT backups.
 944 *
 945 * We do not need take the s_resize_lock for this, because these
 946 * blocks are not otherwise touched by the filesystem code when it is
 947 * mounted.  We don't need to worry about last changing from
 948 * sbi->s_groups_count, because the worst that can happen is that we
 949 * do not copy the full number of backups at this time.  The resize
 950 * which changed s_groups_count will backup again.
 951 */
 952static void update_backups(struct super_block *sb,
 953                           int blk_off, char *data, int size)
 954{
 955        struct ext4_sb_info *sbi = EXT4_SB(sb);
 956        const ext4_group_t last = sbi->s_groups_count;
 957        const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
 958        unsigned three = 1;
 959        unsigned five = 5;
 960        unsigned seven = 7;
 961        ext4_group_t group;
 962        int rest = sb->s_blocksize - size;
 963        handle_t *handle;
 964        int err = 0, err2;
 965
 966        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
 967        if (IS_ERR(handle)) {
 968                group = 1;
 969                err = PTR_ERR(handle);
 970                goto exit_err;
 971        }
 972
 973        ext4_superblock_csum_set(sb, (struct ext4_super_block *)data);
 974
 975        while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
 976                struct buffer_head *bh;
 977
 978                /* Out of journal space, and can't get more - abort - so sad */
 979                if (ext4_handle_valid(handle) &&
 980                    handle->h_buffer_credits == 0 &&
 981                    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
 982                    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
 983                        break;
 984
 985                bh = sb_getblk(sb, group * bpg + blk_off);
 986                if (!bh) {
 987                        err = -EIO;
 988                        break;
 989                }
 990                ext4_debug("update metadata backup %#04lx\n",
 991                          (unsigned long)bh->b_blocknr);
 992                if ((err = ext4_journal_get_write_access(handle, bh)))
 993                        break;
 994                lock_buffer(bh);
 995                memcpy(bh->b_data, data, size);
 996                if (rest)
 997                        memset(bh->b_data + size, 0, rest);
 998                set_buffer_uptodate(bh);
 999                unlock_buffer(bh);
1000                err = ext4_handle_dirty_metadata(handle, NULL, bh);
1001                if (unlikely(err))
1002                        ext4_std_error(sb, err);
1003                brelse(bh);
1004        }
1005        if ((err2 = ext4_journal_stop(handle)) && !err)
1006                err = err2;
1007
1008        /*
1009         * Ugh! Need to have e2fsck write the backup copies.  It is too
1010         * late to revert the resize, we shouldn't fail just because of
1011         * the backup copies (they are only needed in case of corruption).
1012         *
1013         * However, if we got here we have a journal problem too, so we
1014         * can't really start a transaction to mark the superblock.
1015         * Chicken out and just set the flag on the hope it will be written
1016         * to disk, and if not - we will simply wait until next fsck.
1017         */
1018exit_err:
1019        if (err) {
1020                ext4_warning(sb, "can't update backup for group %u (err %d), "
1021                             "forcing fsck on next reboot", group, err);
1022                sbi->s_mount_state &= ~EXT4_VALID_FS;
1023                sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1024                mark_buffer_dirty(sbi->s_sbh);
1025        }
1026}
1027
1028/*
1029 * ext4_add_new_descs() adds @count group descriptor of groups
1030 * starting at @group
1031 *
1032 * @handle: journal handle
1033 * @sb: super block
1034 * @group: the group no. of the first group desc to be added
1035 * @resize_inode: the resize inode
1036 * @count: number of group descriptors to be added
1037 */
1038static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1039                              ext4_group_t group, struct inode *resize_inode,
1040                              ext4_group_t count)
1041{
1042        struct ext4_sb_info *sbi = EXT4_SB(sb);
1043        struct ext4_super_block *es = sbi->s_es;
1044        struct buffer_head *gdb_bh;
1045        int i, gdb_off, gdb_num, err = 0;
1046
1047        for (i = 0; i < count; i++, group++) {
1048                int reserved_gdb = ext4_bg_has_super(sb, group) ?
1049                        le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1050
1051                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1052                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1053
1054                /*
1055                 * We will only either add reserved group blocks to a backup group
1056                 * or remove reserved blocks for the first group in a new group block.
1057                 * Doing both would be mean more complex code, and sane people don't
1058                 * use non-sparse filesystems anymore.  This is already checked above.
1059                 */
1060                if (gdb_off) {
1061                        gdb_bh = sbi->s_group_desc[gdb_num];
1062                        err = ext4_journal_get_write_access(handle, gdb_bh);
1063
1064                        if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1065                                err = reserve_backup_gdb(handle, resize_inode, group);
1066                } else
1067                        err = add_new_gdb(handle, resize_inode, group);
1068                if (err)
1069                        break;
1070        }
1071        return err;
1072}
1073
1074static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1075{
1076        struct buffer_head *bh = sb_getblk(sb, block);
1077        if (!bh)
1078                return NULL;
1079
1080        if (bitmap_uptodate(bh))
1081                return bh;
1082
1083        lock_buffer(bh);
1084        if (bh_submit_read(bh) < 0) {
1085                unlock_buffer(bh);
1086                brelse(bh);
1087                return NULL;
1088        }
1089        unlock_buffer(bh);
1090
1091        return bh;
1092}
1093
1094static int ext4_set_bitmap_checksums(struct super_block *sb,
1095                                     ext4_group_t group,
1096                                     struct ext4_group_desc *gdp,
1097                                     struct ext4_new_group_data *group_data)
1098{
1099        struct buffer_head *bh;
1100
1101        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1102                                        EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1103                return 0;
1104
1105        bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1106        if (!bh)
1107                return -EIO;
1108        ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1109                                   EXT4_INODES_PER_GROUP(sb) / 8);
1110        brelse(bh);
1111
1112        bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1113        if (!bh)
1114                return -EIO;
1115        ext4_block_bitmap_csum_set(sb, group, gdp, bh,
1116                                   EXT4_BLOCKS_PER_GROUP(sb) / 8);
1117        brelse(bh);
1118
1119        return 0;
1120}
1121
1122/*
1123 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1124 */
1125static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1126                                struct ext4_new_flex_group_data *flex_gd)
1127{
1128        struct ext4_new_group_data      *group_data = flex_gd->groups;
1129        struct ext4_group_desc          *gdp;
1130        struct ext4_sb_info             *sbi = EXT4_SB(sb);
1131        struct buffer_head              *gdb_bh;
1132        ext4_group_t                    group;
1133        __u16                           *bg_flags = flex_gd->bg_flags;
1134        int                             i, gdb_off, gdb_num, err = 0;
1135        
1136
1137        for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1138                group = group_data->group;
1139
1140                gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1141                gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1142
1143                /*
1144                 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1145                 */
1146                gdb_bh = sbi->s_group_desc[gdb_num];
1147                /* Update group descriptor block for new group */
1148                gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1149                                                 gdb_off * EXT4_DESC_SIZE(sb));
1150
1151                memset(gdp, 0, EXT4_DESC_SIZE(sb));
1152                ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1153                ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1154                err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1155                if (err) {
1156                        ext4_std_error(sb, err);
1157                        break;
1158                }
1159
1160                ext4_inode_table_set(sb, gdp, group_data->inode_table);
1161                ext4_free_group_clusters_set(sb, gdp,
1162                                             EXT4_B2C(sbi, group_data->free_blocks_count));
1163                ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1164                gdp->bg_flags = cpu_to_le16(*bg_flags);
1165                ext4_group_desc_csum_set(sb, group, gdp);
1166
1167                err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1168                if (unlikely(err)) {
1169                        ext4_std_error(sb, err);
1170                        break;
1171                }
1172
1173                /*
1174                 * We can allocate memory for mb_alloc based on the new group
1175                 * descriptor
1176                 */
1177                err = ext4_mb_add_groupinfo(sb, group, gdp);
1178                if (err)
1179                        break;
1180        }
1181        return err;
1182}
1183
1184/*
1185 * ext4_update_super() updates the super block so that the newly added
1186 * groups can be seen by the filesystem.
1187 *
1188 * @sb: super block
1189 * @flex_gd: new added groups
1190 */
1191static void ext4_update_super(struct super_block *sb,
1192                             struct ext4_new_flex_group_data *flex_gd)
1193{
1194        ext4_fsblk_t blocks_count = 0;
1195        ext4_fsblk_t free_blocks = 0;
1196        ext4_fsblk_t reserved_blocks = 0;
1197        struct ext4_new_group_data *group_data = flex_gd->groups;
1198        struct ext4_sb_info *sbi = EXT4_SB(sb);
1199        struct ext4_super_block *es = sbi->s_es;
1200        int i;
1201
1202        BUG_ON(flex_gd->count == 0 || group_data == NULL);
1203        /*
1204         * Make the new blocks and inodes valid next.  We do this before
1205         * increasing the group count so that once the group is enabled,
1206         * all of its blocks and inodes are already valid.
1207         *
1208         * We always allocate group-by-group, then block-by-block or
1209         * inode-by-inode within a group, so enabling these
1210         * blocks/inodes before the group is live won't actually let us
1211         * allocate the new space yet.
1212         */
1213        for (i = 0; i < flex_gd->count; i++) {
1214                blocks_count += group_data[i].blocks_count;
1215                free_blocks += group_data[i].free_blocks_count;
1216        }
1217
1218        reserved_blocks = ext4_r_blocks_count(es) * 100;
1219        do_div(reserved_blocks, ext4_blocks_count(es));
1220        reserved_blocks *= blocks_count;
1221        do_div(reserved_blocks, 100);
1222
1223        ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1224        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1225        le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1226                     flex_gd->count);
1227        le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1228                     flex_gd->count);
1229
1230        /*
1231         * We need to protect s_groups_count against other CPUs seeing
1232         * inconsistent state in the superblock.
1233         *
1234         * The precise rules we use are:
1235         *
1236         * * Writers must perform a smp_wmb() after updating all
1237         *   dependent data and before modifying the groups count
1238         *
1239         * * Readers must perform an smp_rmb() after reading the groups
1240         *   count and before reading any dependent data.
1241         *
1242         * NB. These rules can be relaxed when checking the group count
1243         * while freeing data, as we can only allocate from a block
1244         * group after serialising against the group count, and we can
1245         * only then free after serialising in turn against that
1246         * allocation.
1247         */
1248        smp_wmb();
1249
1250        /* Update the global fs size fields */
1251        sbi->s_groups_count += flex_gd->count;
1252
1253        /* Update the reserved block counts only once the new group is
1254         * active. */
1255        ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1256                                reserved_blocks);
1257
1258        /* Update the free space counts */
1259        percpu_counter_add(&sbi->s_freeclusters_counter,
1260                           EXT4_B2C(sbi, free_blocks));
1261        percpu_counter_add(&sbi->s_freeinodes_counter,
1262                           EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1263
1264        if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1265                                      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1266            sbi->s_log_groups_per_flex) {
1267                ext4_group_t flex_group;
1268                flex_group = ext4_flex_group(sbi, group_data[0].group);
1269                atomic_add(EXT4_B2C(sbi, free_blocks),
1270                           &sbi->s_flex_groups[flex_group].free_clusters);
1271                atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1272                           &sbi->s_flex_groups[flex_group].free_inodes);
1273        }
1274
1275        /*
1276         * Update the fs overhead information
1277         */
1278        ext4_calculate_overhead(sb);
1279
1280        if (test_opt(sb, DEBUG))
1281                printk(KERN_DEBUG "EXT4-fs: added group %u:"
1282                       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1283                       blocks_count, free_blocks, reserved_blocks);
1284}
1285
1286/* Add a flex group to an fs. Ensure we handle all possible error conditions
1287 * _before_ we start modifying the filesystem, because we cannot abort the
1288 * transaction and not have it write the data to disk.
1289 */
1290static int ext4_flex_group_add(struct super_block *sb,
1291                               struct inode *resize_inode,
1292                               struct ext4_new_flex_group_data *flex_gd)
1293{
1294        struct ext4_sb_info *sbi = EXT4_SB(sb);
1295        struct ext4_super_block *es = sbi->s_es;
1296        ext4_fsblk_t o_blocks_count;
1297        ext4_grpblk_t last;
1298        ext4_group_t group;
1299        handle_t *handle;
1300        unsigned reserved_gdb;
1301        int err = 0, err2 = 0, credit;
1302
1303        BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1304
1305        reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1306        o_blocks_count = ext4_blocks_count(es);
1307        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1308        BUG_ON(last);
1309
1310        err = setup_new_flex_group_blocks(sb, flex_gd);
1311        if (err)
1312                goto exit;
1313        /*
1314         * We will always be modifying at least the superblock and  GDT
1315         * block.  If we are adding a group past the last current GDT block,
1316         * we will also modify the inode and the dindirect block.  If we
1317         * are adding a group with superblock/GDT backups  we will also
1318         * modify each of the reserved GDT dindirect blocks.
1319         */
1320        credit = flex_gd->count * 4 + reserved_gdb;
1321        handle = ext4_journal_start_sb(sb, credit);
1322        if (IS_ERR(handle)) {
1323                err = PTR_ERR(handle);
1324                goto exit;
1325        }
1326
1327        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1328        if (err)
1329                goto exit_journal;
1330
1331        group = flex_gd->groups[0].group;
1332        BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1333        err = ext4_add_new_descs(handle, sb, group,
1334                                resize_inode, flex_gd->count);
1335        if (err)
1336                goto exit_journal;
1337
1338        err = ext4_setup_new_descs(handle, sb, flex_gd);
1339        if (err)
1340                goto exit_journal;
1341
1342        ext4_update_super(sb, flex_gd);
1343
1344        err = ext4_handle_dirty_super(handle, sb);
1345
1346exit_journal:
1347        err2 = ext4_journal_stop(handle);
1348        if (!err)
1349                err = err2;
1350
1351        if (!err) {
1352                int i;
1353                update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1354                               sizeof(struct ext4_super_block));
1355                for (i = 0; i < flex_gd->count; i++, group++) {
1356                        struct buffer_head *gdb_bh;
1357                        int gdb_num;
1358                        gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
1359                        gdb_bh = sbi->s_group_desc[gdb_num];
1360                        update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1361                                       gdb_bh->b_size);
1362                }
1363        }
1364exit:
1365        return err;
1366}
1367
1368static int ext4_setup_next_flex_gd(struct super_block *sb,
1369                                    struct ext4_new_flex_group_data *flex_gd,
1370                                    ext4_fsblk_t n_blocks_count,
1371                                    unsigned long flexbg_size)
1372{
1373        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1374        struct ext4_new_group_data *group_data = flex_gd->groups;
1375        ext4_fsblk_t o_blocks_count;
1376        ext4_group_t n_group;
1377        ext4_group_t group;
1378        ext4_group_t last_group;
1379        ext4_grpblk_t last;
1380        ext4_grpblk_t blocks_per_group;
1381        unsigned long i;
1382
1383        blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1384
1385        o_blocks_count = ext4_blocks_count(es);
1386
1387        if (o_blocks_count == n_blocks_count)
1388                return 0;
1389
1390        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1391        BUG_ON(last);
1392        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1393
1394        last_group = group | (flexbg_size - 1);
1395        if (last_group > n_group)
1396                last_group = n_group;
1397
1398        flex_gd->count = last_group - group + 1;
1399
1400        for (i = 0; i < flex_gd->count; i++) {
1401                int overhead;
1402
1403                group_data[i].group = group + i;
1404                group_data[i].blocks_count = blocks_per_group;
1405                overhead = ext4_bg_has_super(sb, group + i) ?
1406                           (1 + ext4_bg_num_gdb(sb, group + i) +
1407                            le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
1408                group_data[i].free_blocks_count = blocks_per_group - overhead;
1409                if (ext4_has_group_desc_csum(sb))
1410                        flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1411                                               EXT4_BG_INODE_UNINIT;
1412                else
1413                        flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1414        }
1415
1416        if (last_group == n_group && ext4_has_group_desc_csum(sb))
1417                /* We need to initialize block bitmap of last group. */
1418                flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1419
1420        if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1421                group_data[i - 1].blocks_count = last + 1;
1422                group_data[i - 1].free_blocks_count -= blocks_per_group-
1423                                        last - 1;
1424        }
1425
1426        return 1;
1427}
1428
1429/* Add group descriptor data to an existing or new group descriptor block.
1430 * Ensure we handle all possible error conditions _before_ we start modifying
1431 * the filesystem, because we cannot abort the transaction and not have it
1432 * write the data to disk.
1433 *
1434 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1435 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1436 *
1437 * We only need to hold the superblock lock while we are actually adding
1438 * in the new group's counts to the superblock.  Prior to that we have
1439 * not really "added" the group at all.  We re-check that we are still
1440 * adding in the last group in case things have changed since verifying.
1441 */
1442int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1443{
1444        struct ext4_new_flex_group_data flex_gd;
1445        struct ext4_sb_info *sbi = EXT4_SB(sb);
1446        struct ext4_super_block *es = sbi->s_es;
1447        int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1448                le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1449        struct inode *inode = NULL;
1450        int gdb_off, gdb_num;
1451        int err;
1452        __u16 bg_flags = 0;
1453
1454        gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1455        gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1456
1457        if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1458                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1459                ext4_warning(sb, "Can't resize non-sparse filesystem further");
1460                return -EPERM;
1461        }
1462
1463        if (ext4_blocks_count(es) + input->blocks_count <
1464            ext4_blocks_count(es)) {
1465                ext4_warning(sb, "blocks_count overflow");
1466                return -EINVAL;
1467        }
1468
1469        if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1470            le32_to_cpu(es->s_inodes_count)) {
1471                ext4_warning(sb, "inodes_count overflow");
1472                return -EINVAL;
1473        }
1474
1475        if (reserved_gdb || gdb_off == 0) {
1476                if (!EXT4_HAS_COMPAT_FEATURE(sb,
1477                                             EXT4_FEATURE_COMPAT_RESIZE_INODE)
1478                    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1479                        ext4_warning(sb,
1480                                     "No reserved GDT blocks, can't resize");
1481                        return -EPERM;
1482                }
1483                inode = ext4_iget(sb, EXT4_RESIZE_INO);
1484                if (IS_ERR(inode)) {
1485                        ext4_warning(sb, "Error opening resize inode");
1486                        return PTR_ERR(inode);
1487                }
1488        }
1489
1490
1491        err = verify_group_input(sb, input);
1492        if (err)
1493                goto out;
1494
1495        flex_gd.count = 1;
1496        flex_gd.groups = input;
1497        flex_gd.bg_flags = &bg_flags;
1498        err = ext4_flex_group_add(sb, inode, &flex_gd);
1499out:
1500        iput(inode);
1501        return err;
1502} /* ext4_group_add */
1503
1504/*
1505 * extend a group without checking assuming that checking has been done.
1506 */
1507static int ext4_group_extend_no_check(struct super_block *sb,
1508                                      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1509{
1510        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1511        handle_t *handle;
1512        int err = 0, err2;
1513
1514        /* We will update the superblock, one block bitmap, and
1515         * one group descriptor via ext4_group_add_blocks().
1516         */
1517        handle = ext4_journal_start_sb(sb, 3);
1518        if (IS_ERR(handle)) {
1519                err = PTR_ERR(handle);
1520                ext4_warning(sb, "error %d on journal start", err);
1521                return err;
1522        }
1523
1524        err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1525        if (err) {
1526                ext4_warning(sb, "error %d on journal write access", err);
1527                goto errout;
1528        }
1529
1530        ext4_blocks_count_set(es, o_blocks_count + add);
1531        ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1532        ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1533                   o_blocks_count + add);
1534        /* We add the blocks to the bitmap and set the group need init bit */
1535        err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1536        if (err)
1537                goto errout;
1538        ext4_handle_dirty_super(handle, sb);
1539        ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1540                   o_blocks_count + add);
1541errout:
1542        err2 = ext4_journal_stop(handle);
1543        if (err2 && !err)
1544                err = err2;
1545
1546        if (!err) {
1547                if (test_opt(sb, DEBUG))
1548                        printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1549                               "blocks\n", ext4_blocks_count(es));
1550                update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1551                               sizeof(struct ext4_super_block));
1552        }
1553        return err;
1554}
1555
1556/*
1557 * Extend the filesystem to the new number of blocks specified.  This entry
1558 * point is only used to extend the current filesystem to the end of the last
1559 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1560 * for emergencies (because it has no dependencies on reserved blocks).
1561 *
1562 * If we _really_ wanted, we could use default values to call ext4_group_add()
1563 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1564 * GDT blocks are reserved to grow to the desired size.
1565 */
1566int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1567                      ext4_fsblk_t n_blocks_count)
1568{
1569        ext4_fsblk_t o_blocks_count;
1570        ext4_grpblk_t last;
1571        ext4_grpblk_t add;
1572        struct buffer_head *bh;
1573        int err;
1574        ext4_group_t group;
1575
1576        o_blocks_count = ext4_blocks_count(es);
1577
1578        if (test_opt(sb, DEBUG))
1579                ext4_msg(sb, KERN_DEBUG,
1580                         "extending last group from %llu to %llu blocks",
1581                         o_blocks_count, n_blocks_count);
1582
1583        if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1584                return 0;
1585
1586        if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1587                ext4_msg(sb, KERN_ERR,
1588                         "filesystem too large to resize to %llu blocks safely",
1589                         n_blocks_count);
1590                if (sizeof(sector_t) < 8)
1591                        ext4_warning(sb, "CONFIG_LBDAF not enabled");
1592                return -EINVAL;
1593        }
1594
1595        if (n_blocks_count < o_blocks_count) {
1596                ext4_warning(sb, "can't shrink FS - resize aborted");
1597                return -EINVAL;
1598        }
1599
1600        /* Handle the remaining blocks in the last group only. */
1601        ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1602
1603        if (last == 0) {
1604                ext4_warning(sb, "need to use ext2online to resize further");
1605                return -EPERM;
1606        }
1607
1608        add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1609
1610        if (o_blocks_count + add < o_blocks_count) {
1611                ext4_warning(sb, "blocks_count overflow");
1612                return -EINVAL;
1613        }
1614
1615        if (o_blocks_count + add > n_blocks_count)
1616                add = n_blocks_count - o_blocks_count;
1617
1618        if (o_blocks_count + add < n_blocks_count)
1619                ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1620                             o_blocks_count + add, add);
1621
1622        /* See if the device is actually as big as what was requested */
1623        bh = sb_bread(sb, o_blocks_count + add - 1);
1624        if (!bh) {
1625                ext4_warning(sb, "can't read last block, resize aborted");
1626                return -ENOSPC;
1627        }
1628        brelse(bh);
1629
1630        err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1631        return err;
1632} /* ext4_group_extend */
1633
1634/*
1635 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1636 *
1637 * @sb: super block of the fs to be resized
1638 * @n_blocks_count: the number of blocks resides in the resized fs
1639 */
1640int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1641{
1642        struct ext4_new_flex_group_data *flex_gd = NULL;
1643        struct ext4_sb_info *sbi = EXT4_SB(sb);
1644        struct ext4_super_block *es = sbi->s_es;
1645        struct buffer_head *bh;
1646        struct inode *resize_inode;
1647        ext4_fsblk_t o_blocks_count;
1648        ext4_group_t o_group;
1649        ext4_group_t n_group;
1650        ext4_grpblk_t offset, add;
1651        unsigned long n_desc_blocks;
1652        unsigned long o_desc_blocks;
1653        unsigned long desc_blocks;
1654        int err = 0, flexbg_size = 1;
1655
1656        o_blocks_count = ext4_blocks_count(es);
1657
1658        if (test_opt(sb, DEBUG))
1659                ext4_msg(sb, KERN_DEBUG, "resizing filesystem from %llu "
1660                       "to %llu blocks", o_blocks_count, n_blocks_count);
1661
1662        if (n_blocks_count < o_blocks_count) {
1663                /* On-line shrinking not supported */
1664                ext4_warning(sb, "can't shrink FS - resize aborted");
1665                return -EINVAL;
1666        }
1667
1668        if (n_blocks_count == o_blocks_count)
1669                /* Nothing need to do */
1670                return 0;
1671
1672        ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
1673        ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1674
1675        n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
1676                        EXT4_DESC_PER_BLOCK(sb);
1677        o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1678                        EXT4_DESC_PER_BLOCK(sb);
1679        desc_blocks = n_desc_blocks - o_desc_blocks;
1680
1681        if (desc_blocks &&
1682            (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
1683             le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
1684                ext4_warning(sb, "No reserved GDT blocks, can't resize");
1685                return -EPERM;
1686        }
1687
1688        resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1689        if (IS_ERR(resize_inode)) {
1690                ext4_warning(sb, "Error opening resize inode");
1691                return PTR_ERR(resize_inode);
1692        }
1693
1694        /* See if the device is actually as big as what was requested */
1695        bh = sb_bread(sb, n_blocks_count - 1);
1696        if (!bh) {
1697                ext4_warning(sb, "can't read last block, resize aborted");
1698                return -ENOSPC;
1699        }
1700        brelse(bh);
1701
1702        /* extend the last group */
1703        if (n_group == o_group)
1704                add = n_blocks_count - o_blocks_count;
1705        else
1706                add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1707        if (add > 0) {
1708                err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1709                if (err)
1710                        goto out;
1711        }
1712
1713        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1714            es->s_log_groups_per_flex)
1715                flexbg_size = 1 << es->s_log_groups_per_flex;
1716
1717        o_blocks_count = ext4_blocks_count(es);
1718        if (o_blocks_count == n_blocks_count)
1719                goto out;
1720
1721        flex_gd = alloc_flex_gd(flexbg_size);
1722        if (flex_gd == NULL) {
1723                err = -ENOMEM;
1724                goto out;
1725        }
1726
1727        /* Add flex groups. Note that a regular group is a
1728         * flex group with 1 group.
1729         */
1730        while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1731                                              flexbg_size)) {
1732                ext4_alloc_group_tables(sb, flex_gd, flexbg_size);
1733                err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1734                if (unlikely(err))
1735                        break;
1736        }
1737
1738out:
1739        if (flex_gd)
1740                free_flex_gd(flex_gd);
1741
1742        iput(resize_inode);
1743        if (test_opt(sb, DEBUG))
1744                ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
1745                       "upto %llu blocks", o_blocks_count, n_blocks_count);
1746        return err;
1747}
1748
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.