linux/fs/hfsplus/extents.c
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   1/*
   2 *  linux/fs/hfsplus/extents.c
   3 *
   4 * Copyright (C) 2001
   5 * Brad Boyer (flar@allandria.com)
   6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7 *
   8 * Handling of Extents both in catalog and extents overflow trees
   9 */
  10
  11#include <linux/errno.h>
  12#include <linux/fs.h>
  13#include <linux/pagemap.h>
  14
  15#include "hfsplus_fs.h"
  16#include "hfsplus_raw.h"
  17
  18/* Compare two extents keys, returns 0 on same, pos/neg for difference */
  19int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
  20                        const hfsplus_btree_key *k2)
  21{
  22        __be32 k1id, k2id;
  23        __be32 k1s, k2s;
  24
  25        k1id = k1->ext.cnid;
  26        k2id = k2->ext.cnid;
  27        if (k1id != k2id)
  28                return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
  29
  30        if (k1->ext.fork_type != k2->ext.fork_type)
  31                return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
  32
  33        k1s = k1->ext.start_block;
  34        k2s = k2->ext.start_block;
  35        if (k1s == k2s)
  36                return 0;
  37        return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
  38}
  39
  40static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
  41                                  u32 block, u8 type)
  42{
  43        key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
  44        key->ext.cnid = cpu_to_be32(cnid);
  45        key->ext.start_block = cpu_to_be32(block);
  46        key->ext.fork_type = type;
  47        key->ext.pad = 0;
  48}
  49
  50static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
  51{
  52        int i;
  53        u32 count;
  54
  55        for (i = 0; i < 8; ext++, i++) {
  56                count = be32_to_cpu(ext->block_count);
  57                if (off < count)
  58                        return be32_to_cpu(ext->start_block) + off;
  59                off -= count;
  60        }
  61        /* panic? */
  62        return 0;
  63}
  64
  65static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
  66{
  67        int i;
  68        u32 count = 0;
  69
  70        for (i = 0; i < 8; ext++, i++)
  71                count += be32_to_cpu(ext->block_count);
  72        return count;
  73}
  74
  75static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
  76{
  77        int i;
  78
  79        ext += 7;
  80        for (i = 0; i < 7; ext--, i++)
  81                if (ext->block_count)
  82                        break;
  83        return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
  84}
  85
  86static void __hfsplus_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
  87{
  88        int res;
  89
  90        hfsplus_ext_build_key(fd->search_key, inode->i_ino, HFSPLUS_I(inode).cached_start,
  91                              HFSPLUS_IS_RSRC(inode) ?  HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
  92        res = hfs_brec_find(fd);
  93        if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_NEW) {
  94                if (res != -ENOENT)
  95                        return;
  96                hfs_brec_insert(fd, HFSPLUS_I(inode).cached_extents, sizeof(hfsplus_extent_rec));
  97                HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
  98        } else {
  99                if (res)
 100                        return;
 101                hfs_bnode_write(fd->bnode, HFSPLUS_I(inode).cached_extents, fd->entryoffset, fd->entrylength);
 102                HFSPLUS_I(inode).flags &= ~HFSPLUS_FLG_EXT_DIRTY;
 103        }
 104}
 105
 106void hfsplus_ext_write_extent(struct inode *inode)
 107{
 108        if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY) {
 109                struct hfs_find_data fd;
 110
 111                hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
 112                __hfsplus_ext_write_extent(inode, &fd);
 113                hfs_find_exit(&fd);
 114        }
 115}
 116
 117static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
 118                                            struct hfsplus_extent *extent,
 119                                            u32 cnid, u32 block, u8 type)
 120{
 121        int res;
 122
 123        hfsplus_ext_build_key(fd->search_key, cnid, block, type);
 124        fd->key->ext.cnid = 0;
 125        res = hfs_brec_find(fd);
 126        if (res && res != -ENOENT)
 127                return res;
 128        if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
 129            fd->key->ext.fork_type != fd->search_key->ext.fork_type)
 130                return -ENOENT;
 131        if (fd->entrylength != sizeof(hfsplus_extent_rec))
 132                return -EIO;
 133        hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfsplus_extent_rec));
 134        return 0;
 135}
 136
 137static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
 138{
 139        int res;
 140
 141        if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY)
 142                __hfsplus_ext_write_extent(inode, fd);
 143
 144        res = __hfsplus_ext_read_extent(fd, HFSPLUS_I(inode).cached_extents, inode->i_ino,
 145                                        block, HFSPLUS_IS_RSRC(inode) ? HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
 146        if (!res) {
 147                HFSPLUS_I(inode).cached_start = be32_to_cpu(fd->key->ext.start_block);
 148                HFSPLUS_I(inode).cached_blocks = hfsplus_ext_block_count(HFSPLUS_I(inode).cached_extents);
 149        } else {
 150                HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
 151                HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
 152        }
 153        return res;
 154}
 155
 156static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
 157{
 158        struct hfs_find_data fd;
 159        int res;
 160
 161        if (block >= HFSPLUS_I(inode).cached_start &&
 162            block < HFSPLUS_I(inode).cached_start + HFSPLUS_I(inode).cached_blocks)
 163                return 0;
 164
 165        hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
 166        res = __hfsplus_ext_cache_extent(&fd, inode, block);
 167        hfs_find_exit(&fd);
 168        return res;
 169}
 170
 171/* Get a block at iblock for inode, possibly allocating if create */
 172int hfsplus_get_block(struct inode *inode, sector_t iblock,
 173                      struct buffer_head *bh_result, int create)
 174{
 175        struct super_block *sb;
 176        int res = -EIO;
 177        u32 ablock, dblock, mask;
 178        int shift;
 179
 180        sb = inode->i_sb;
 181
 182        /* Convert inode block to disk allocation block */
 183        shift = HFSPLUS_SB(sb).alloc_blksz_shift - sb->s_blocksize_bits;
 184        ablock = iblock >> HFSPLUS_SB(sb).fs_shift;
 185
 186        if (iblock >= HFSPLUS_I(inode).fs_blocks) {
 187                if (iblock > HFSPLUS_I(inode).fs_blocks || !create)
 188                        return -EIO;
 189                if (ablock >= HFSPLUS_I(inode).alloc_blocks) {
 190                        res = hfsplus_file_extend(inode);
 191                        if (res)
 192                                return res;
 193                }
 194        } else
 195                create = 0;
 196
 197        if (ablock < HFSPLUS_I(inode).first_blocks) {
 198                dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).first_extents, ablock);
 199                goto done;
 200        }
 201
 202        down(&HFSPLUS_I(inode).extents_lock);
 203        res = hfsplus_ext_read_extent(inode, ablock);
 204        if (!res) {
 205                dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
 206                                             HFSPLUS_I(inode).cached_start);
 207        } else {
 208                up(&HFSPLUS_I(inode).extents_lock);
 209                return -EIO;
 210        }
 211        up(&HFSPLUS_I(inode).extents_lock);
 212
 213done:
 214        dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
 215        mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
 216        map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
 217        if (create) {
 218                set_buffer_new(bh_result);
 219                HFSPLUS_I(inode).phys_size += sb->s_blocksize;
 220                HFSPLUS_I(inode).fs_blocks++;
 221                inode_add_bytes(inode, sb->s_blocksize);
 222                mark_inode_dirty(inode);
 223        }
 224        return 0;
 225}
 226
 227static void hfsplus_dump_extent(struct hfsplus_extent *extent)
 228{
 229        int i;
 230
 231        dprint(DBG_EXTENT, "   ");
 232        for (i = 0; i < 8; i++)
 233                dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
 234                                 be32_to_cpu(extent[i].block_count));
 235        dprint(DBG_EXTENT, "\n");
 236}
 237
 238static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
 239                              u32 alloc_block, u32 block_count)
 240{
 241        u32 count, start;
 242        int i;
 243
 244        hfsplus_dump_extent(extent);
 245        for (i = 0; i < 8; extent++, i++) {
 246                count = be32_to_cpu(extent->block_count);
 247                if (offset == count) {
 248                        start = be32_to_cpu(extent->start_block);
 249                        if (alloc_block != start + count) {
 250                                if (++i >= 8)
 251                                        return -ENOSPC;
 252                                extent++;
 253                                extent->start_block = cpu_to_be32(alloc_block);
 254                        } else
 255                                block_count += count;
 256                        extent->block_count = cpu_to_be32(block_count);
 257                        return 0;
 258                } else if (offset < count)
 259                        break;
 260                offset -= count;
 261        }
 262        /* panic? */
 263        return -EIO;
 264}
 265
 266static int hfsplus_free_extents(struct super_block *sb,
 267                                struct hfsplus_extent *extent,
 268                                u32 offset, u32 block_nr)
 269{
 270        u32 count, start;
 271        int i;
 272
 273        hfsplus_dump_extent(extent);
 274        for (i = 0; i < 8; extent++, i++) {
 275                count = be32_to_cpu(extent->block_count);
 276                if (offset == count)
 277                        goto found;
 278                else if (offset < count)
 279                        break;
 280                offset -= count;
 281        }
 282        /* panic? */
 283        return -EIO;
 284found:
 285        for (;;) {
 286                start = be32_to_cpu(extent->start_block);
 287                if (count <= block_nr) {
 288                        hfsplus_block_free(sb, start, count);
 289                        extent->block_count = 0;
 290                        extent->start_block = 0;
 291                        block_nr -= count;
 292                } else {
 293                        count -= block_nr;
 294                        hfsplus_block_free(sb, start + count, block_nr);
 295                        extent->block_count = cpu_to_be32(count);
 296                        block_nr = 0;
 297                }
 298                if (!block_nr || !i)
 299                        return 0;
 300                i--;
 301                extent--;
 302                count = be32_to_cpu(extent->block_count);
 303        }
 304}
 305
 306int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
 307{
 308        struct hfs_find_data fd;
 309        hfsplus_extent_rec ext_entry;
 310        u32 total_blocks, blocks, start;
 311        int res, i;
 312
 313        total_blocks = be32_to_cpu(fork->total_blocks);
 314        if (!total_blocks)
 315                return 0;
 316
 317        blocks = 0;
 318        for (i = 0; i < 8; i++)
 319                blocks += be32_to_cpu(fork->extents[i].block_count);
 320
 321        res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
 322        if (res)
 323                return res;
 324        if (total_blocks == blocks)
 325                return 0;
 326
 327        hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 328        do {
 329                res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
 330                                                total_blocks, type);
 331                if (res)
 332                        break;
 333                start = be32_to_cpu(fd.key->ext.start_block);
 334                hfsplus_free_extents(sb, ext_entry,
 335                                     total_blocks - start,
 336                                     total_blocks);
 337                hfs_brec_remove(&fd);
 338                total_blocks = start;
 339        } while (total_blocks > blocks);
 340        hfs_find_exit(&fd);
 341
 342        return res;
 343}
 344
 345int hfsplus_file_extend(struct inode *inode)
 346{
 347        struct super_block *sb = inode->i_sb;
 348        u32 start, len, goal;
 349        int res;
 350
 351        if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
 352                // extend alloc file
 353                printk(KERN_ERR "hfs: extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
 354                        HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
 355                return -ENOSPC;
 356        }
 357
 358        down(&HFSPLUS_I(inode).extents_lock);
 359        if (HFSPLUS_I(inode).alloc_blocks == HFSPLUS_I(inode).first_blocks)
 360                goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).first_extents);
 361        else {
 362                res = hfsplus_ext_read_extent(inode, HFSPLUS_I(inode).alloc_blocks);
 363                if (res)
 364                        goto out;
 365                goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).cached_extents);
 366        }
 367
 368        len = HFSPLUS_I(inode).clump_blocks;
 369        start = hfsplus_block_allocate(sb, HFSPLUS_SB(sb).total_blocks, goal, &len);
 370        if (start >= HFSPLUS_SB(sb).total_blocks) {
 371                start = hfsplus_block_allocate(sb, goal, 0, &len);
 372                if (start >= goal) {
 373                        res = -ENOSPC;
 374                        goto out;
 375                }
 376        }
 377
 378        dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
 379        if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).first_blocks) {
 380                if (!HFSPLUS_I(inode).first_blocks) {
 381                        dprint(DBG_EXTENT, "first extents\n");
 382                        /* no extents yet */
 383                        HFSPLUS_I(inode).first_extents[0].start_block = cpu_to_be32(start);
 384                        HFSPLUS_I(inode).first_extents[0].block_count = cpu_to_be32(len);
 385                        res = 0;
 386                } else {
 387                        /* try to append to extents in inode */
 388                        res = hfsplus_add_extent(HFSPLUS_I(inode).first_extents,
 389                                                 HFSPLUS_I(inode).alloc_blocks,
 390                                                 start, len);
 391                        if (res == -ENOSPC)
 392                                goto insert_extent;
 393                }
 394                if (!res) {
 395                        hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
 396                        HFSPLUS_I(inode).first_blocks += len;
 397                }
 398        } else {
 399                res = hfsplus_add_extent(HFSPLUS_I(inode).cached_extents,
 400                                         HFSPLUS_I(inode).alloc_blocks -
 401                                         HFSPLUS_I(inode).cached_start,
 402                                         start, len);
 403                if (!res) {
 404                        hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 405                        HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
 406                        HFSPLUS_I(inode).cached_blocks += len;
 407                } else if (res == -ENOSPC)
 408                        goto insert_extent;
 409        }
 410out:
 411        up(&HFSPLUS_I(inode).extents_lock);
 412        if (!res) {
 413                HFSPLUS_I(inode).alloc_blocks += len;
 414                mark_inode_dirty(inode);
 415        }
 416        return res;
 417
 418insert_extent:
 419        dprint(DBG_EXTENT, "insert new extent\n");
 420        hfsplus_ext_write_extent(inode);
 421
 422        memset(HFSPLUS_I(inode).cached_extents, 0, sizeof(hfsplus_extent_rec));
 423        HFSPLUS_I(inode).cached_extents[0].start_block = cpu_to_be32(start);
 424        HFSPLUS_I(inode).cached_extents[0].block_count = cpu_to_be32(len);
 425        hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 426        HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW;
 427        HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).alloc_blocks;
 428        HFSPLUS_I(inode).cached_blocks = len;
 429
 430        res = 0;
 431        goto out;
 432}
 433
 434void hfsplus_file_truncate(struct inode *inode)
 435{
 436        struct super_block *sb = inode->i_sb;
 437        struct hfs_find_data fd;
 438        u32 alloc_cnt, blk_cnt, start;
 439        int res;
 440
 441        dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
 442               (long long)HFSPLUS_I(inode).phys_size, inode->i_size);
 443        if (inode->i_size > HFSPLUS_I(inode).phys_size) {
 444                struct address_space *mapping = inode->i_mapping;
 445                struct page *page;
 446                void *fsdata;
 447                u32 size = inode->i_size;
 448                int res;
 449
 450                res = pagecache_write_begin(NULL, mapping, size, 0,
 451                                                AOP_FLAG_UNINTERRUPTIBLE,
 452                                                &page, &fsdata);
 453                if (res)
 454                        return;
 455                res = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
 456                if (res < 0)
 457                        return;
 458                mark_inode_dirty(inode);
 459                return;
 460        } else if (inode->i_size == HFSPLUS_I(inode).phys_size)
 461                return;
 462
 463        blk_cnt = (inode->i_size + HFSPLUS_SB(sb).alloc_blksz - 1) >> HFSPLUS_SB(sb).alloc_blksz_shift;
 464        alloc_cnt = HFSPLUS_I(inode).alloc_blocks;
 465        if (blk_cnt == alloc_cnt)
 466                goto out;
 467
 468        down(&HFSPLUS_I(inode).extents_lock);
 469        hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
 470        while (1) {
 471                if (alloc_cnt == HFSPLUS_I(inode).first_blocks) {
 472                        hfsplus_free_extents(sb, HFSPLUS_I(inode).first_extents,
 473                                             alloc_cnt, alloc_cnt - blk_cnt);
 474                        hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
 475                        HFSPLUS_I(inode).first_blocks = blk_cnt;
 476                        break;
 477                }
 478                res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
 479                if (res)
 480                        break;
 481                start = HFSPLUS_I(inode).cached_start;
 482                hfsplus_free_extents(sb, HFSPLUS_I(inode).cached_extents,
 483                                     alloc_cnt - start, alloc_cnt - blk_cnt);
 484                hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
 485                if (blk_cnt > start) {
 486                        HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
 487                        break;
 488                }
 489                alloc_cnt = start;
 490                HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
 491                HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
 492                hfs_brec_remove(&fd);
 493        }
 494        hfs_find_exit(&fd);
 495        up(&HFSPLUS_I(inode).extents_lock);
 496
 497        HFSPLUS_I(inode).alloc_blocks = blk_cnt;
 498out:
 499        HFSPLUS_I(inode).phys_size = inode->i_size;
 500        HFSPLUS_I(inode).fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 501        inode_set_bytes(inode, HFSPLUS_I(inode).fs_blocks << sb->s_blocksize_bits);
 502        mark_inode_dirty(inode);
 503}
 504