linux/fs/f2fs/dir.c
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   1/*
   2 * fs/f2fs/dir.c
   3 *
   4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5 *             http://www.samsung.com/
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11#include <linux/fs.h>
  12#include <linux/f2fs_fs.h>
  13#include "f2fs.h"
  14#include "node.h"
  15#include "acl.h"
  16
  17static unsigned long dir_blocks(struct inode *inode)
  18{
  19        return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))
  20                                                        >> PAGE_CACHE_SHIFT;
  21}
  22
  23static unsigned int dir_buckets(unsigned int level)
  24{
  25        if (level < MAX_DIR_HASH_DEPTH / 2)
  26                return 1 << level;
  27        else
  28                return 1 << ((MAX_DIR_HASH_DEPTH / 2) - 1);
  29}
  30
  31static unsigned int bucket_blocks(unsigned int level)
  32{
  33        if (level < MAX_DIR_HASH_DEPTH / 2)
  34                return 2;
  35        else
  36                return 4;
  37}
  38
  39static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
  40        [F2FS_FT_UNKNOWN]       = DT_UNKNOWN,
  41        [F2FS_FT_REG_FILE]      = DT_REG,
  42        [F2FS_FT_DIR]           = DT_DIR,
  43        [F2FS_FT_CHRDEV]        = DT_CHR,
  44        [F2FS_FT_BLKDEV]        = DT_BLK,
  45        [F2FS_FT_FIFO]          = DT_FIFO,
  46        [F2FS_FT_SOCK]          = DT_SOCK,
  47        [F2FS_FT_SYMLINK]       = DT_LNK,
  48};
  49
  50#define S_SHIFT 12
  51static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
  52        [S_IFREG >> S_SHIFT]    = F2FS_FT_REG_FILE,
  53        [S_IFDIR >> S_SHIFT]    = F2FS_FT_DIR,
  54        [S_IFCHR >> S_SHIFT]    = F2FS_FT_CHRDEV,
  55        [S_IFBLK >> S_SHIFT]    = F2FS_FT_BLKDEV,
  56        [S_IFIFO >> S_SHIFT]    = F2FS_FT_FIFO,
  57        [S_IFSOCK >> S_SHIFT]   = F2FS_FT_SOCK,
  58        [S_IFLNK >> S_SHIFT]    = F2FS_FT_SYMLINK,
  59};
  60
  61static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
  62{
  63        umode_t mode = inode->i_mode;
  64        de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
  65}
  66
  67static unsigned long dir_block_index(unsigned int level, unsigned int idx)
  68{
  69        unsigned long i;
  70        unsigned long bidx = 0;
  71
  72        for (i = 0; i < level; i++)
  73                bidx += dir_buckets(i) * bucket_blocks(i);
  74        bidx += idx * bucket_blocks(level);
  75        return bidx;
  76}
  77
  78static bool early_match_name(const char *name, size_t namelen,
  79                        f2fs_hash_t namehash, struct f2fs_dir_entry *de)
  80{
  81        if (le16_to_cpu(de->name_len) != namelen)
  82                return false;
  83
  84        if (de->hash_code != namehash)
  85                return false;
  86
  87        return true;
  88}
  89
  90static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
  91                        const char *name, size_t namelen, int *max_slots,
  92                        f2fs_hash_t namehash, struct page **res_page)
  93{
  94        struct f2fs_dir_entry *de;
  95        unsigned long bit_pos, end_pos, next_pos;
  96        struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
  97        int slots;
  98
  99        bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 100                                        NR_DENTRY_IN_BLOCK, 0);
 101        while (bit_pos < NR_DENTRY_IN_BLOCK) {
 102                de = &dentry_blk->dentry[bit_pos];
 103                slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
 104
 105                if (early_match_name(name, namelen, namehash, de)) {
 106                        if (!memcmp(dentry_blk->filename[bit_pos],
 107                                                        name, namelen)) {
 108                                *res_page = dentry_page;
 109                                goto found;
 110                        }
 111                }
 112                next_pos = bit_pos + slots;
 113                bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 114                                NR_DENTRY_IN_BLOCK, next_pos);
 115                if (bit_pos >= NR_DENTRY_IN_BLOCK)
 116                        end_pos = NR_DENTRY_IN_BLOCK;
 117                else
 118                        end_pos = bit_pos;
 119                if (*max_slots < end_pos - next_pos)
 120                        *max_slots = end_pos - next_pos;
 121        }
 122
 123        de = NULL;
 124        kunmap(dentry_page);
 125found:
 126        return de;
 127}
 128
 129static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 130                unsigned int level, const char *name, size_t namelen,
 131                        f2fs_hash_t namehash, struct page **res_page)
 132{
 133        int s = GET_DENTRY_SLOTS(namelen);
 134        unsigned int nbucket, nblock;
 135        unsigned int bidx, end_block;
 136        struct page *dentry_page;
 137        struct f2fs_dir_entry *de = NULL;
 138        bool room = false;
 139        int max_slots = 0;
 140
 141        BUG_ON(level > MAX_DIR_HASH_DEPTH);
 142
 143        nbucket = dir_buckets(level);
 144        nblock = bucket_blocks(level);
 145
 146        bidx = dir_block_index(level, le32_to_cpu(namehash) % nbucket);
 147        end_block = bidx + nblock;
 148
 149        for (; bidx < end_block; bidx++) {
 150                /* no need to allocate new dentry pages to all the indices */
 151                dentry_page = find_data_page(dir, bidx, true);
 152                if (IS_ERR(dentry_page)) {
 153                        room = true;
 154                        continue;
 155                }
 156
 157                de = find_in_block(dentry_page, name, namelen,
 158                                        &max_slots, namehash, res_page);
 159                if (de)
 160                        break;
 161
 162                if (max_slots >= s)
 163                        room = true;
 164                f2fs_put_page(dentry_page, 0);
 165        }
 166
 167        if (!de && room && F2FS_I(dir)->chash != namehash) {
 168                F2FS_I(dir)->chash = namehash;
 169                F2FS_I(dir)->clevel = level;
 170        }
 171
 172        return de;
 173}
 174
 175/*
 176 * Find an entry in the specified directory with the wanted name.
 177 * It returns the page where the entry was found (as a parameter - res_page),
 178 * and the entry itself. Page is returned mapped and unlocked.
 179 * Entry is guaranteed to be valid.
 180 */
 181struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 182                        struct qstr *child, struct page **res_page)
 183{
 184        const char *name = child->name;
 185        size_t namelen = child->len;
 186        unsigned long npages = dir_blocks(dir);
 187        struct f2fs_dir_entry *de = NULL;
 188        f2fs_hash_t name_hash;
 189        unsigned int max_depth;
 190        unsigned int level;
 191
 192        if (namelen > F2FS_NAME_LEN)
 193                return NULL;
 194
 195        if (npages == 0)
 196                return NULL;
 197
 198        *res_page = NULL;
 199
 200        name_hash = f2fs_dentry_hash(name, namelen);
 201        max_depth = F2FS_I(dir)->i_current_depth;
 202
 203        for (level = 0; level < max_depth; level++) {
 204                de = find_in_level(dir, level, name,
 205                                namelen, name_hash, res_page);
 206                if (de)
 207                        break;
 208        }
 209        if (!de && F2FS_I(dir)->chash != name_hash) {
 210                F2FS_I(dir)->chash = name_hash;
 211                F2FS_I(dir)->clevel = level - 1;
 212        }
 213        return de;
 214}
 215
 216struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
 217{
 218        struct page *page = NULL;
 219        struct f2fs_dir_entry *de = NULL;
 220        struct f2fs_dentry_block *dentry_blk = NULL;
 221
 222        page = get_lock_data_page(dir, 0);
 223        if (IS_ERR(page))
 224                return NULL;
 225
 226        dentry_blk = kmap(page);
 227        de = &dentry_blk->dentry[1];
 228        *p = page;
 229        unlock_page(page);
 230        return de;
 231}
 232
 233ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
 234{
 235        ino_t res = 0;
 236        struct f2fs_dir_entry *de;
 237        struct page *page;
 238
 239        de = f2fs_find_entry(dir, qstr, &page);
 240        if (de) {
 241                res = le32_to_cpu(de->ino);
 242                kunmap(page);
 243                f2fs_put_page(page, 0);
 244        }
 245
 246        return res;
 247}
 248
 249void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
 250                struct page *page, struct inode *inode)
 251{
 252        lock_page(page);
 253        wait_on_page_writeback(page);
 254        de->ino = cpu_to_le32(inode->i_ino);
 255        set_de_type(de, inode);
 256        kunmap(page);
 257        set_page_dirty(page);
 258        dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 259        mark_inode_dirty(dir);
 260
 261        /* update parent inode number before releasing dentry page */
 262        F2FS_I(inode)->i_pino = dir->i_ino;
 263
 264        f2fs_put_page(page, 1);
 265}
 266
 267void init_dent_inode(const struct qstr *name, struct page *ipage)
 268{
 269        struct f2fs_node *rn;
 270
 271        if (IS_ERR(ipage))
 272                return;
 273
 274        wait_on_page_writeback(ipage);
 275
 276        /* copy name info. to this inode page */
 277        rn = (struct f2fs_node *)page_address(ipage);
 278        rn->i.i_namelen = cpu_to_le32(name->len);
 279        memcpy(rn->i.i_name, name->name, name->len);
 280        set_page_dirty(ipage);
 281}
 282
 283static int make_empty_dir(struct inode *inode, struct inode *parent)
 284{
 285        struct page *dentry_page;
 286        struct f2fs_dentry_block *dentry_blk;
 287        struct f2fs_dir_entry *de;
 288        void *kaddr;
 289
 290        dentry_page = get_new_data_page(inode, 0, true);
 291        if (IS_ERR(dentry_page))
 292                return PTR_ERR(dentry_page);
 293
 294        kaddr = kmap_atomic(dentry_page);
 295        dentry_blk = (struct f2fs_dentry_block *)kaddr;
 296
 297        de = &dentry_blk->dentry[0];
 298        de->name_len = cpu_to_le16(1);
 299        de->hash_code = 0;
 300        de->ino = cpu_to_le32(inode->i_ino);
 301        memcpy(dentry_blk->filename[0], ".", 1);
 302        set_de_type(de, inode);
 303
 304        de = &dentry_blk->dentry[1];
 305        de->hash_code = 0;
 306        de->name_len = cpu_to_le16(2);
 307        de->ino = cpu_to_le32(parent->i_ino);
 308        memcpy(dentry_blk->filename[1], "..", 2);
 309        set_de_type(de, inode);
 310
 311        test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
 312        test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
 313        kunmap_atomic(kaddr);
 314
 315        set_page_dirty(dentry_page);
 316        f2fs_put_page(dentry_page, 1);
 317        return 0;
 318}
 319
 320static int init_inode_metadata(struct inode *inode,
 321                struct inode *dir, const struct qstr *name)
 322{
 323        if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
 324                int err;
 325                err = new_inode_page(inode, name);
 326                if (err)
 327                        return err;
 328
 329                if (S_ISDIR(inode->i_mode)) {
 330                        err = make_empty_dir(inode, dir);
 331                        if (err) {
 332                                remove_inode_page(inode);
 333                                return err;
 334                        }
 335                }
 336
 337                err = f2fs_init_acl(inode, dir);
 338                if (err) {
 339                        remove_inode_page(inode);
 340                        return err;
 341                }
 342        } else {
 343                struct page *ipage;
 344                ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
 345                if (IS_ERR(ipage))
 346                        return PTR_ERR(ipage);
 347                set_cold_node(inode, ipage);
 348                init_dent_inode(name, ipage);
 349                f2fs_put_page(ipage, 1);
 350        }
 351        if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
 352                inc_nlink(inode);
 353                update_inode_page(inode);
 354        }
 355        return 0;
 356}
 357
 358static void update_parent_metadata(struct inode *dir, struct inode *inode,
 359                                                unsigned int current_depth)
 360{
 361        bool need_dir_update = false;
 362
 363        if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
 364                if (S_ISDIR(inode->i_mode)) {
 365                        inc_nlink(dir);
 366                        need_dir_update = true;
 367                }
 368                clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
 369        }
 370        dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 371        if (F2FS_I(dir)->i_current_depth != current_depth) {
 372                F2FS_I(dir)->i_current_depth = current_depth;
 373                need_dir_update = true;
 374        }
 375
 376        if (need_dir_update)
 377                update_inode_page(dir);
 378        else
 379                mark_inode_dirty(dir);
 380
 381        if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
 382                clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
 383}
 384
 385static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
 386{
 387        int bit_start = 0;
 388        int zero_start, zero_end;
 389next:
 390        zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
 391                                                NR_DENTRY_IN_BLOCK,
 392                                                bit_start);
 393        if (zero_start >= NR_DENTRY_IN_BLOCK)
 394                return NR_DENTRY_IN_BLOCK;
 395
 396        zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
 397                                                NR_DENTRY_IN_BLOCK,
 398                                                zero_start);
 399        if (zero_end - zero_start >= slots)
 400                return zero_start;
 401
 402        bit_start = zero_end + 1;
 403
 404        if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
 405                return NR_DENTRY_IN_BLOCK;
 406        goto next;
 407}
 408
 409/*
 410 * Caller should grab and release a mutex by calling mutex_lock_op() and
 411 * mutex_unlock_op().
 412 */
 413int __f2fs_add_link(struct inode *dir, const struct qstr *name, struct inode *inode)
 414{
 415        unsigned int bit_pos;
 416        unsigned int level;
 417        unsigned int current_depth;
 418        unsigned long bidx, block;
 419        f2fs_hash_t dentry_hash;
 420        struct f2fs_dir_entry *de;
 421        unsigned int nbucket, nblock;
 422        size_t namelen = name->len;
 423        struct page *dentry_page = NULL;
 424        struct f2fs_dentry_block *dentry_blk = NULL;
 425        int slots = GET_DENTRY_SLOTS(namelen);
 426        int err = 0;
 427        int i;
 428
 429        dentry_hash = f2fs_dentry_hash(name->name, name->len);
 430        level = 0;
 431        current_depth = F2FS_I(dir)->i_current_depth;
 432        if (F2FS_I(dir)->chash == dentry_hash) {
 433                level = F2FS_I(dir)->clevel;
 434                F2FS_I(dir)->chash = 0;
 435        }
 436
 437start:
 438        if (current_depth == MAX_DIR_HASH_DEPTH)
 439                return -ENOSPC;
 440
 441        /* Increase the depth, if required */
 442        if (level == current_depth)
 443                ++current_depth;
 444
 445        nbucket = dir_buckets(level);
 446        nblock = bucket_blocks(level);
 447
 448        bidx = dir_block_index(level, (le32_to_cpu(dentry_hash) % nbucket));
 449
 450        for (block = bidx; block <= (bidx + nblock - 1); block++) {
 451                dentry_page = get_new_data_page(dir, block, true);
 452                if (IS_ERR(dentry_page))
 453                        return PTR_ERR(dentry_page);
 454
 455                dentry_blk = kmap(dentry_page);
 456                bit_pos = room_for_filename(dentry_blk, slots);
 457                if (bit_pos < NR_DENTRY_IN_BLOCK)
 458                        goto add_dentry;
 459
 460                kunmap(dentry_page);
 461                f2fs_put_page(dentry_page, 1);
 462        }
 463
 464        /* Move to next level to find the empty slot for new dentry */
 465        ++level;
 466        goto start;
 467add_dentry:
 468        err = init_inode_metadata(inode, dir, name);
 469        if (err)
 470                goto fail;
 471
 472        wait_on_page_writeback(dentry_page);
 473
 474        de = &dentry_blk->dentry[bit_pos];
 475        de->hash_code = dentry_hash;
 476        de->name_len = cpu_to_le16(namelen);
 477        memcpy(dentry_blk->filename[bit_pos], name->name, name->len);
 478        de->ino = cpu_to_le32(inode->i_ino);
 479        set_de_type(de, inode);
 480        for (i = 0; i < slots; i++)
 481                test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
 482        set_page_dirty(dentry_page);
 483
 484        update_parent_metadata(dir, inode, current_depth);
 485
 486        /* update parent inode number before releasing dentry page */
 487        F2FS_I(inode)->i_pino = dir->i_ino;
 488fail:
 489        kunmap(dentry_page);
 490        f2fs_put_page(dentry_page, 1);
 491        return err;
 492}
 493
 494/*
 495 * It only removes the dentry from the dentry page,corresponding name
 496 * entry in name page does not need to be touched during deletion.
 497 */
 498void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
 499                                                struct inode *inode)
 500{
 501        struct  f2fs_dentry_block *dentry_blk;
 502        unsigned int bit_pos;
 503        struct address_space *mapping = page->mapping;
 504        struct inode *dir = mapping->host;
 505        struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
 506        int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
 507        void *kaddr = page_address(page);
 508        int i;
 509
 510        lock_page(page);
 511        wait_on_page_writeback(page);
 512
 513        dentry_blk = (struct f2fs_dentry_block *)kaddr;
 514        bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
 515        for (i = 0; i < slots; i++)
 516                test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
 517
 518        /* Let's check and deallocate this dentry page */
 519        bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 520                        NR_DENTRY_IN_BLOCK,
 521                        0);
 522        kunmap(page); /* kunmap - pair of f2fs_find_entry */
 523        set_page_dirty(page);
 524
 525        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 526
 527        if (inode && S_ISDIR(inode->i_mode)) {
 528                drop_nlink(dir);
 529                update_inode_page(dir);
 530        } else {
 531                mark_inode_dirty(dir);
 532        }
 533
 534        if (inode) {
 535                inode->i_ctime = CURRENT_TIME;
 536                drop_nlink(inode);
 537                if (S_ISDIR(inode->i_mode)) {
 538                        drop_nlink(inode);
 539                        i_size_write(inode, 0);
 540                }
 541                update_inode_page(inode);
 542
 543                if (inode->i_nlink == 0)
 544                        add_orphan_inode(sbi, inode->i_ino);
 545        }
 546
 547        if (bit_pos == NR_DENTRY_IN_BLOCK) {
 548                truncate_hole(dir, page->index, page->index + 1);
 549                clear_page_dirty_for_io(page);
 550                ClearPageUptodate(page);
 551                dec_page_count(sbi, F2FS_DIRTY_DENTS);
 552                inode_dec_dirty_dents(dir);
 553        }
 554        f2fs_put_page(page, 1);
 555}
 556
 557bool f2fs_empty_dir(struct inode *dir)
 558{
 559        unsigned long bidx;
 560        struct page *dentry_page;
 561        unsigned int bit_pos;
 562        struct  f2fs_dentry_block *dentry_blk;
 563        unsigned long nblock = dir_blocks(dir);
 564
 565        for (bidx = 0; bidx < nblock; bidx++) {
 566                void *kaddr;
 567                dentry_page = get_lock_data_page(dir, bidx);
 568                if (IS_ERR(dentry_page)) {
 569                        if (PTR_ERR(dentry_page) == -ENOENT)
 570                                continue;
 571                        else
 572                                return false;
 573                }
 574
 575                kaddr = kmap_atomic(dentry_page);
 576                dentry_blk = (struct f2fs_dentry_block *)kaddr;
 577                if (bidx == 0)
 578                        bit_pos = 2;
 579                else
 580                        bit_pos = 0;
 581                bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 582                                                NR_DENTRY_IN_BLOCK,
 583                                                bit_pos);
 584                kunmap_atomic(kaddr);
 585
 586                f2fs_put_page(dentry_page, 1);
 587
 588                if (bit_pos < NR_DENTRY_IN_BLOCK)
 589                        return false;
 590        }
 591        return true;
 592}
 593
 594static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)
 595{
 596        unsigned long pos = file->f_pos;
 597        struct inode *inode = file_inode(file);
 598        unsigned long npages = dir_blocks(inode);
 599        unsigned char *types = NULL;
 600        unsigned int bit_pos = 0, start_bit_pos = 0;
 601        int over = 0;
 602        struct f2fs_dentry_block *dentry_blk = NULL;
 603        struct f2fs_dir_entry *de = NULL;
 604        struct page *dentry_page = NULL;
 605        unsigned int n = 0;
 606        unsigned char d_type = DT_UNKNOWN;
 607        int slots;
 608
 609        types = f2fs_filetype_table;
 610        bit_pos = (pos % NR_DENTRY_IN_BLOCK);
 611        n = (pos / NR_DENTRY_IN_BLOCK);
 612
 613        for ( ; n < npages; n++) {
 614                dentry_page = get_lock_data_page(inode, n);
 615                if (IS_ERR(dentry_page))
 616                        continue;
 617
 618                start_bit_pos = bit_pos;
 619                dentry_blk = kmap(dentry_page);
 620                while (bit_pos < NR_DENTRY_IN_BLOCK) {
 621                        d_type = DT_UNKNOWN;
 622                        bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 623                                                        NR_DENTRY_IN_BLOCK,
 624                                                        bit_pos);
 625                        if (bit_pos >= NR_DENTRY_IN_BLOCK)
 626                                break;
 627
 628                        de = &dentry_blk->dentry[bit_pos];
 629                        if (types && de->file_type < F2FS_FT_MAX)
 630                                d_type = types[de->file_type];
 631
 632                        over = filldir(dirent,
 633                                        dentry_blk->filename[bit_pos],
 634                                        le16_to_cpu(de->name_len),
 635                                        (n * NR_DENTRY_IN_BLOCK) + bit_pos,
 636                                        le32_to_cpu(de->ino), d_type);
 637                        if (over) {
 638                                file->f_pos += bit_pos - start_bit_pos;
 639                                goto success;
 640                        }
 641                        slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
 642                        bit_pos += slots;
 643                }
 644                bit_pos = 0;
 645                file->f_pos = (n + 1) * NR_DENTRY_IN_BLOCK;
 646                kunmap(dentry_page);
 647                f2fs_put_page(dentry_page, 1);
 648                dentry_page = NULL;
 649        }
 650success:
 651        if (dentry_page && !IS_ERR(dentry_page)) {
 652                kunmap(dentry_page);
 653                f2fs_put_page(dentry_page, 1);
 654        }
 655
 656        return 0;
 657}
 658
 659const struct file_operations f2fs_dir_operations = {
 660        .llseek         = generic_file_llseek,
 661        .read           = generic_read_dir,
 662        .readdir        = f2fs_readdir,
 663        .fsync          = f2fs_sync_file,
 664        .unlocked_ioctl = f2fs_ioctl,
 665};
 666