linux/fs/hfsplus/extents.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/hfsplus/extents.c
   4 *
   5 * Copyright (C) 2001
   6 * Brad Boyer (flar@allandria.com)
   7 * (C) 2003 Ardis Technologies <roman@ardistech.com>
   8 *
   9 * Handling of Extents both in catalog and extents overflow trees
  10 */
  11
  12#include <linux/errno.h>
  13#include <linux/fs.h>
  14#include <linux/pagemap.h>
  15
  16#include "hfsplus_fs.h"
  17#include "hfsplus_raw.h"
  18
  19/* Compare two extents keys, returns 0 on same, pos/neg for difference */
  20int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
  21                        const hfsplus_btree_key *k2)
  22{
  23        __be32 k1id, k2id;
  24        __be32 k1s, k2s;
  25
  26        k1id = k1->ext.cnid;
  27        k2id = k2->ext.cnid;
  28        if (k1id != k2id)
  29                return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
  30
  31        if (k1->ext.fork_type != k2->ext.fork_type)
  32                return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
  33
  34        k1s = k1->ext.start_block;
  35        k2s = k2->ext.start_block;
  36        if (k1s == k2s)
  37                return 0;
  38        return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
  39}
  40
  41static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
  42                                  u32 block, u8 type)
  43{
  44        key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
  45        key->ext.cnid = cpu_to_be32(cnid);
  46        key->ext.start_block = cpu_to_be32(block);
  47        key->ext.fork_type = type;
  48        key->ext.pad = 0;
  49}
  50
  51static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
  52{
  53        int i;
  54        u32 count;
  55
  56        for (i = 0; i < 8; ext++, i++) {
  57                count = be32_to_cpu(ext->block_count);
  58                if (off < count)
  59                        return be32_to_cpu(ext->start_block) + off;
  60                off -= count;
  61        }
  62        /* panic? */
  63        return 0;
  64}
  65
  66static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
  67{
  68        int i;
  69        u32 count = 0;
  70
  71        for (i = 0; i < 8; ext++, i++)
  72                count += be32_to_cpu(ext->block_count);
  73        return count;
  74}
  75
  76static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
  77{
  78        int i;
  79
  80        ext += 7;
  81        for (i = 0; i < 7; ext--, i++)
  82                if (ext->block_count)
  83                        break;
  84        return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
  85}
  86
  87static int __hfsplus_ext_write_extent(struct inode *inode,
  88                struct hfs_find_data *fd)
  89{
  90        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  91        int res;
  92
  93        WARN_ON(!mutex_is_locked(&hip->extents_lock));
  94
  95        hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
  96                              HFSPLUS_IS_RSRC(inode) ?
  97                                HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
  98
  99        res = hfs_brec_find(fd, hfs_find_rec_by_key);
 100        if (hip->extent_state & HFSPLUS_EXT_NEW) {
 101                if (res != -ENOENT)
 102                        return res;
 103                /* Fail early and avoid ENOSPC during the btree operation */
 104                res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
 105                if (res)
 106                        return res;
 107                hfs_brec_insert(fd, hip->cached_extents,
 108                                sizeof(hfsplus_extent_rec));
 109                hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 110        } else {
 111                if (res)
 112                        return res;
 113                hfs_bnode_write(fd->bnode, hip->cached_extents,
 114                                fd->entryoffset, fd->entrylength);
 115                hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
 116        }
 117
 118        /*
 119         * We can't just use hfsplus_mark_inode_dirty here, because we
 120         * also get called from hfsplus_write_inode, which should not
 121         * redirty the inode.  Instead the callers have to be careful
 122         * to explicily mark the inode dirty, too.
 123         */
 124        set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
 125
 126        return 0;
 127}
 128
 129static int hfsplus_ext_write_extent_locked(struct inode *inode)
 130{
 131        int res = 0;
 132
 133        if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
 134                struct hfs_find_data fd;
 135
 136                res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 137                if (res)
 138                        return res;
 139                res = __hfsplus_ext_write_extent(inode, &fd);
 140                hfs_find_exit(&fd);
 141        }
 142        return res;
 143}
 144
 145int hfsplus_ext_write_extent(struct inode *inode)
 146{
 147        int res;
 148
 149        mutex_lock(&HFSPLUS_I(inode)->extents_lock);
 150        res = hfsplus_ext_write_extent_locked(inode);
 151        mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
 152
 153        return res;
 154}
 155
 156static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 157                                            struct hfsplus_extent *extent,
 158                                            u32 cnid, u32 block, u8 type)
 159{
 160        int res;
 161
 162        hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 163        fd->key->ext.cnid = 0;
 164        res = hfs_brec_find(fd, hfs_find_rec_by_key);
 165        if (res && res != -ENOENT)
 166                return res;
 167        if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 168            fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 169                return -ENOENT;
 170        if (fd->entrylength != sizeof(hfsplus_extent_rec))
 171                return -EIO;
 172        hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
 173                sizeof(hfsplus_extent_rec));
 174        return 0;
 175}
 176
 177static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
 178                struct inode *inode, u32 block)
 179{
 180        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 181        int res;
 182
 183        WARN_ON(!mutex_is_locked(&hip->extents_lock));
 184
 185        if (hip->extent_state & HFSPLUS_EXT_DIRTY) {
 186                res = __hfsplus_ext_write_extent(inode, fd);
 187                if (res)
 188                        return res;
 189        }
 190
 191        res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
 192                                        block, HFSPLUS_IS_RSRC(inode) ?
 193                                                HFSPLUS_TYPE_RSRC :
 194                                                HFSPLUS_TYPE_DATA);
 195        if (!res) {
 196                hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
 197                hip->cached_blocks =
 198                        hfsplus_ext_block_count(hip->cached_extents);
 199        } else {
 200                hip->cached_start = hip->cached_blocks = 0;
 201                hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 202        }
 203        return res;
 204}
 205
 206static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 207{
 208        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 209        struct hfs_find_data fd;
 210        int res;
 211
 212        if (block >= hip->cached_start &&
 213            block < hip->cached_start + hip->cached_blocks)
 214                return 0;
 215
 216        res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
 217        if (!res) {
 218                res = __hfsplus_ext_cache_extent(&fd, inode, block);
 219                hfs_find_exit(&fd);
 220        }
 221        return res;
 222}
 223
 224/* Get a block at iblock for inode, possibly allocating if create */
 225int hfsplus_get_block(struct inode *inode, sector_t iblock,
 226                      struct buffer_head *bh_result, int create)
 227{
 228        struct super_block *sb = inode->i_sb;
 229        struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 230        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 231        int res = -EIO;
 232        u32 ablock, dblock, mask;
 233        sector_t sector;
 234        int was_dirty = 0;
 235
 236        /* Convert inode block to disk allocation block */
 237        ablock = iblock >> sbi->fs_shift;
 238
 239        if (iblock >= hip->fs_blocks) {
 240                if (!create)
 241                        return 0;
 242                if (iblock > hip->fs_blocks)
 243                        return -EIO;
 244                if (ablock >= hip->alloc_blocks) {
 245                        res = hfsplus_file_extend(inode, false);
 246                        if (res)
 247                                return res;
 248                }
 249        } else
 250                create = 0;
 251
 252        if (ablock < hip->first_blocks) {
 253                dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
 254                goto done;
 255        }
 256
 257        if (inode->i_ino == HFSPLUS_EXT_CNID)
 258                return -EIO;
 259
 260        mutex_lock(&hip->extents_lock);
 261
 262        /*
 263         * hfsplus_ext_read_extent will write out a cached extent into
 264         * the extents btree.  In that case we may have to mark the inode
 265         * dirty even for a pure read of an extent here.
 266         */
 267        was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
 268        res = hfsplus_ext_read_extent(inode, ablock);
 269        if (res) {
 270                mutex_unlock(&hip->extents_lock);
 271                return -EIO;
 272        }
 273        dblock = hfsplus_ext_find_block(hip->cached_extents,
 274                                        ablock - hip->cached_start);
 275        mutex_unlock(&hip->extents_lock);
 276
 277done:
 278        hfs_dbg(EXTENT, "get_block(%lu): %llu - %u\n",
 279                inode->i_ino, (long long)iblock, dblock);
 280
 281        mask = (1 << sbi->fs_shift) - 1;
 282        sector = ((sector_t)dblock << sbi->fs_shift) +
 283                  sbi->blockoffset + (iblock & mask);
 284        map_bh(bh_result, sb, sector);
 285
 286        if (create) {
 287                set_buffer_new(bh_result);
 288                hip->phys_size += sb->s_blocksize;
 289                hip->fs_blocks++;
 290                inode_add_bytes(inode, sb->s_blocksize);
 291        }
 292        if (create || was_dirty)
 293                mark_inode_dirty(inode);
 294        return 0;
 295}
 296
 297static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 298{
 299        int i;
 300
 301        hfs_dbg(EXTENT, "   ");
 302        for (i = 0; i < 8; i++)
 303                hfs_dbg_cont(EXTENT, " %u:%u",
 304                             be32_to_cpu(extent[i].start_block),
 305                             be32_to_cpu(extent[i].block_count));
 306        hfs_dbg_cont(EXTENT, "\n");
 307}
 308
 309static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 310                              u32 alloc_block, u32 block_count)
 311{
 312        u32 count, start;
 313        int i;
 314
 315        hfsplus_dump_extent(extent);
 316        for (i = 0; i < 8; extent++, i++) {
 317                count = be32_to_cpu(extent->block_count);
 318                if (offset == count) {
 319                        start = be32_to_cpu(extent->start_block);
 320                        if (alloc_block != start + count) {
 321                                if (++i >= 8)
 322                                        return -ENOSPC;
 323                                extent++;
 324                                extent->start_block = cpu_to_be32(alloc_block);
 325                        } else
 326                                block_count += count;
 327                        extent->block_count = cpu_to_be32(block_count);
 328                        return 0;
 329                } else if (offset < count)
 330                        break;
 331                offset -= count;
 332        }
 333        /* panic? */
 334        return -EIO;
 335}
 336
 337static int hfsplus_free_extents(struct super_block *sb,
 338                                struct hfsplus_extent *extent,
 339                                u32 offset, u32 block_nr)
 340{
 341        u32 count, start;
 342        int i;
 343        int err = 0;
 344
 345        /* Mapping the allocation file may lock the extent tree */
 346        WARN_ON(mutex_is_locked(&HFSPLUS_SB(sb)->ext_tree->tree_lock));
 347
 348        hfsplus_dump_extent(extent);
 349        for (i = 0; i < 8; extent++, i++) {
 350                count = be32_to_cpu(extent->block_count);
 351                if (offset == count)
 352                        goto found;
 353                else if (offset < count)
 354                        break;
 355                offset -= count;
 356        }
 357        /* panic? */
 358        return -EIO;
 359found:
 360        for (;;) {
 361                start = be32_to_cpu(extent->start_block);
 362                if (count <= block_nr) {
 363                        err = hfsplus_block_free(sb, start, count);
 364                        if (err) {
 365                                pr_err("can't free extent\n");
 366                                hfs_dbg(EXTENT, " start: %u count: %u\n",
 367                                        start, count);
 368                        }
 369                        extent->block_count = 0;
 370                        extent->start_block = 0;
 371                        block_nr -= count;
 372                } else {
 373                        count -= block_nr;
 374                        err = hfsplus_block_free(sb, start + count, block_nr);
 375                        if (err) {
 376                                pr_err("can't free extent\n");
 377                                hfs_dbg(EXTENT, " start: %u count: %u\n",
 378                                        start, count);
 379                        }
 380                        extent->block_count = cpu_to_be32(count);
 381                        block_nr = 0;
 382                }
 383                if (!block_nr || !i) {
 384                        /*
 385                         * Try to free all extents and
 386                         * return only last error
 387                         */
 388                        return err;
 389                }
 390                i--;
 391                extent--;
 392                count = be32_to_cpu(extent->block_count);
 393        }
 394}
 395
 396int hfsplus_free_fork(struct super_block *sb, u32 cnid,
 397                struct hfsplus_fork_raw *fork, int type)
 398{
 399        struct hfs_find_data fd;
 400        hfsplus_extent_rec ext_entry;
 401        u32 total_blocks, blocks, start;
 402        int res, i;
 403
 404        total_blocks = be32_to_cpu(fork->total_blocks);
 405        if (!total_blocks)
 406                return 0;
 407
 408        blocks = 0;
 409        for (i = 0; i < 8; i++)
 410                blocks += be32_to_cpu(fork->extents[i].block_count);
 411
 412        res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 413        if (res)
 414                return res;
 415        if (total_blocks == blocks)
 416                return 0;
 417
 418        res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 419        if (res)
 420                return res;
 421        do {
 422                res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 423                                                total_blocks, type);
 424                if (res)
 425                        break;
 426                start = be32_to_cpu(fd.key->ext.start_block);
 427                hfs_brec_remove(&fd);
 428
 429                mutex_unlock(&fd.tree->tree_lock);
 430                hfsplus_free_extents(sb, ext_entry, total_blocks - start,
 431                                     total_blocks);
 432                total_blocks = start;
 433                mutex_lock(&fd.tree->tree_lock);
 434        } while (total_blocks > blocks);
 435        hfs_find_exit(&fd);
 436
 437        return res;
 438}
 439
 440int hfsplus_file_extend(struct inode *inode, bool zeroout)
 441{
 442        struct super_block *sb = inode->i_sb;
 443        struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 444        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 445        u32 start, len, goal;
 446        int res;
 447
 448        if (sbi->alloc_file->i_size * 8 <
 449            sbi->total_blocks - sbi->free_blocks + 8) {
 450                /* extend alloc file */
 451                pr_err("extend alloc file! (%llu,%u,%u)\n",
 452                       sbi->alloc_file->i_size * 8,
 453                       sbi->total_blocks, sbi->free_blocks);
 454                return -ENOSPC;
 455        }
 456
 457        mutex_lock(&hip->extents_lock);
 458        if (hip->alloc_blocks == hip->first_blocks)
 459                goal = hfsplus_ext_lastblock(hip->first_extents);
 460        else {
 461                res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
 462                if (res)
 463                        goto out;
 464                goal = hfsplus_ext_lastblock(hip->cached_extents);
 465        }
 466
 467        len = hip->clump_blocks;
 468        start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
 469        if (start >= sbi->total_blocks) {
 470                start = hfsplus_block_allocate(sb, goal, 0, &len);
 471                if (start >= goal) {
 472                        res = -ENOSPC;
 473                        goto out;
 474                }
 475        }
 476
 477        if (zeroout) {
 478                res = sb_issue_zeroout(sb, start, len, GFP_NOFS);
 479                if (res)
 480                        goto out;
 481        }
 482
 483        hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 484
 485        if (hip->alloc_blocks <= hip->first_blocks) {
 486                if (!hip->first_blocks) {
 487                        hfs_dbg(EXTENT, "first extents\n");
 488                        /* no extents yet */
 489                        hip->first_extents[0].start_block = cpu_to_be32(start);
 490                        hip->first_extents[0].block_count = cpu_to_be32(len);
 491                        res = 0;
 492                } else {
 493                        /* try to append to extents in inode */
 494                        res = hfsplus_add_extent(hip->first_extents,
 495                                                 hip->alloc_blocks,
 496                                                 start, len);
 497                        if (res == -ENOSPC)
 498                                goto insert_extent;
 499                }
 500                if (!res) {
 501                        hfsplus_dump_extent(hip->first_extents);
 502                        hip->first_blocks += len;
 503                }
 504        } else {
 505                res = hfsplus_add_extent(hip->cached_extents,
 506                                         hip->alloc_blocks - hip->cached_start,
 507                                         start, len);
 508                if (!res) {
 509                        hfsplus_dump_extent(hip->cached_extents);
 510                        hip->extent_state |= HFSPLUS_EXT_DIRTY;
 511                        hip->cached_blocks += len;
 512                } else if (res == -ENOSPC)
 513                        goto insert_extent;
 514        }
 515out:
 516        if (!res) {
 517                hip->alloc_blocks += len;
 518                mutex_unlock(&hip->extents_lock);
 519                hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 520                return 0;
 521        }
 522        mutex_unlock(&hip->extents_lock);
 523        return res;
 524
 525insert_extent:
 526        hfs_dbg(EXTENT, "insert new extent\n");
 527        res = hfsplus_ext_write_extent_locked(inode);
 528        if (res)
 529                goto out;
 530
 531        memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
 532        hip->cached_extents[0].start_block = cpu_to_be32(start);
 533        hip->cached_extents[0].block_count = cpu_to_be32(len);
 534        hfsplus_dump_extent(hip->cached_extents);
 535        hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
 536        hip->cached_start = hip->alloc_blocks;
 537        hip->cached_blocks = len;
 538
 539        res = 0;
 540        goto out;
 541}
 542
 543void hfsplus_file_truncate(struct inode *inode)
 544{
 545        struct super_block *sb = inode->i_sb;
 546        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 547        struct hfs_find_data fd;
 548        u32 alloc_cnt, blk_cnt, start;
 549        int res;
 550
 551        hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
 552                inode->i_ino, (long long)hip->phys_size, inode->i_size);
 553
 554        if (inode->i_size > hip->phys_size) {
 555                struct address_space *mapping = inode->i_mapping;
 556                struct page *page;
 557                void *fsdata;
 558                loff_t size = inode->i_size;
 559
 560                res = pagecache_write_begin(NULL, mapping, size, 0, 0,
 561                                            &page, &fsdata);
 562                if (res)
 563                        return;
 564                res = pagecache_write_end(NULL, mapping, size,
 565                        0, 0, page, fsdata);
 566                if (res < 0)
 567                        return;
 568                mark_inode_dirty(inode);
 569                return;
 570        } else if (inode->i_size == hip->phys_size)
 571                return;
 572
 573        blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
 574                        HFSPLUS_SB(sb)->alloc_blksz_shift;
 575
 576        mutex_lock(&hip->extents_lock);
 577
 578        alloc_cnt = hip->alloc_blocks;
 579        if (blk_cnt == alloc_cnt)
 580                goto out_unlock;
 581
 582        res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
 583        if (res) {
 584                mutex_unlock(&hip->extents_lock);
 585                /* XXX: We lack error handling of hfsplus_file_truncate() */
 586                return;
 587        }
 588        while (1) {
 589                if (alloc_cnt == hip->first_blocks) {
 590                        mutex_unlock(&fd.tree->tree_lock);
 591                        hfsplus_free_extents(sb, hip->first_extents,
 592                                             alloc_cnt, alloc_cnt - blk_cnt);
 593                        hfsplus_dump_extent(hip->first_extents);
 594                        hip->first_blocks = blk_cnt;
 595                        mutex_lock(&fd.tree->tree_lock);
 596                        break;
 597                }
 598                res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 599                if (res)
 600                        break;
 601
 602                start = hip->cached_start;
 603                if (blk_cnt <= start)
 604                        hfs_brec_remove(&fd);
 605                mutex_unlock(&fd.tree->tree_lock);
 606                hfsplus_free_extents(sb, hip->cached_extents,
 607                                     alloc_cnt - start, alloc_cnt - blk_cnt);
 608                hfsplus_dump_extent(hip->cached_extents);
 609                mutex_lock(&fd.tree->tree_lock);
 610                if (blk_cnt > start) {
 611                        hip->extent_state |= HFSPLUS_EXT_DIRTY;
 612                        break;
 613                }
 614                alloc_cnt = start;
 615                hip->cached_start = hip->cached_blocks = 0;
 616                hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
 617        }
 618        hfs_find_exit(&fd);
 619
 620        hip->alloc_blocks = blk_cnt;
 621out_unlock:
 622        mutex_unlock(&hip->extents_lock);
 623        hip->phys_size = inode->i_size;
 624        hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
 625                sb->s_blocksize_bits;
 626        inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
 627        hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 628}
 629