linux/fs/ufs/dir.c
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   1/*
   2 *  linux/fs/ufs/ufs_dir.c
   3 *
   4 * Copyright (C) 1996
   5 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
   6 * Laboratory for Computer Science Research Computing Facility
   7 * Rutgers, The State University of New Jersey
   8 *
   9 * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
  10 *
  11 * 4.4BSD (FreeBSD) support added on February 1st 1998 by
  12 * Niels Kristian Bech Jensen <nkbj@image.dk> partially based
  13 * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
  14 *
  15 * Migration to usage of "page cache" on May 2006 by
  16 * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
  17 */
  18
  19#include <linux/time.h>
  20#include <linux/fs.h>
  21#include <linux/ufs_fs.h>
  22#include <linux/swap.h>
  23
  24#include "ufs.h"
  25#include "swab.h"
  26#include "util.h"
  27
  28/*
  29 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
  30 *
  31 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
  32 */
  33static inline int ufs_match(struct super_block *sb, int len,
  34                const char * const name, struct ufs_dir_entry * de)
  35{
  36        if (len != ufs_get_de_namlen(sb, de))
  37                return 0;
  38        if (!de->d_ino)
  39                return 0;
  40        return !memcmp(name, de->d_name, len);
  41}
  42
  43static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len)
  44{
  45        struct address_space *mapping = page->mapping;
  46        struct inode *dir = mapping->host;
  47        int err = 0;
  48
  49        dir->i_version++;
  50        block_write_end(NULL, mapping, pos, len, len, page, NULL);
  51        if (pos+len > dir->i_size) {
  52                i_size_write(dir, pos+len);
  53                mark_inode_dirty(dir);
  54        }
  55        if (IS_DIRSYNC(dir))
  56                err = write_one_page(page, 1);
  57        else
  58                unlock_page(page);
  59        return err;
  60}
  61
  62static inline void ufs_put_page(struct page *page)
  63{
  64        kunmap(page);
  65        page_cache_release(page);
  66}
  67
  68static inline unsigned long ufs_dir_pages(struct inode *inode)
  69{
  70        return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
  71}
  72
  73ino_t ufs_inode_by_name(struct inode *dir, struct dentry *dentry)
  74{
  75        ino_t res = 0;
  76        struct ufs_dir_entry *de;
  77        struct page *page;
  78        
  79        de = ufs_find_entry(dir, dentry, &page);
  80        if (de) {
  81                res = fs32_to_cpu(dir->i_sb, de->d_ino);
  82                ufs_put_page(page);
  83        }
  84        return res;
  85}
  86
  87
  88/* Releases the page */
  89void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
  90                  struct page *page, struct inode *inode)
  91{
  92        loff_t pos = page_offset(page) +
  93                        (char *) de - (char *) page_address(page);
  94        unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
  95        int err;
  96
  97        lock_page(page);
  98        err = __ufs_write_begin(NULL, page->mapping, pos, len,
  99                                AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
 100        BUG_ON(err);
 101
 102        de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
 103        ufs_set_de_type(dir->i_sb, de, inode->i_mode);
 104
 105        err = ufs_commit_chunk(page, pos, len);
 106        ufs_put_page(page);
 107        dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
 108        mark_inode_dirty(dir);
 109}
 110
 111
 112static void ufs_check_page(struct page *page)
 113{
 114        struct inode *dir = page->mapping->host;
 115        struct super_block *sb = dir->i_sb;
 116        char *kaddr = page_address(page);
 117        unsigned offs, rec_len;
 118        unsigned limit = PAGE_CACHE_SIZE;
 119        const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1;
 120        struct ufs_dir_entry *p;
 121        char *error;
 122
 123        if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
 124                limit = dir->i_size & ~PAGE_CACHE_MASK;
 125                if (limit & chunk_mask)
 126                        goto Ebadsize;
 127                if (!limit)
 128                        goto out;
 129        }
 130        for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) {
 131                p = (struct ufs_dir_entry *)(kaddr + offs);
 132                rec_len = fs16_to_cpu(sb, p->d_reclen);
 133
 134                if (rec_len < UFS_DIR_REC_LEN(1))
 135                        goto Eshort;
 136                if (rec_len & 3)
 137                        goto Ealign;
 138                if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p)))
 139                        goto Enamelen;
 140                if (((offs + rec_len - 1) ^ offs) & ~chunk_mask)
 141                        goto Espan;
 142                if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
 143                                                  UFS_SB(sb)->s_uspi->s_ncg))
 144                        goto Einumber;
 145        }
 146        if (offs != limit)
 147                goto Eend;
 148out:
 149        SetPageChecked(page);
 150        return;
 151
 152        /* Too bad, we had an error */
 153
 154Ebadsize:
 155        ufs_error(sb, "ufs_check_page",
 156                  "size of directory #%lu is not a multiple of chunk size",
 157                  dir->i_ino
 158        );
 159        goto fail;
 160Eshort:
 161        error = "rec_len is smaller than minimal";
 162        goto bad_entry;
 163Ealign:
 164        error = "unaligned directory entry";
 165        goto bad_entry;
 166Enamelen:
 167        error = "rec_len is too small for name_len";
 168        goto bad_entry;
 169Espan:
 170        error = "directory entry across blocks";
 171        goto bad_entry;
 172Einumber:
 173        error = "inode out of bounds";
 174bad_entry:
 175        ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - "
 176                   "offset=%lu, rec_len=%d, name_len=%d",
 177                   dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
 178                   rec_len, ufs_get_de_namlen(sb, p));
 179        goto fail;
 180Eend:
 181        p = (struct ufs_dir_entry *)(kaddr + offs);
 182        ufs_error(sb, __FUNCTION__,
 183                   "entry in directory #%lu spans the page boundary"
 184                   "offset=%lu",
 185                   dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs);
 186fail:
 187        SetPageChecked(page);
 188        SetPageError(page);
 189}
 190
 191static struct page *ufs_get_page(struct inode *dir, unsigned long n)
 192{
 193        struct address_space *mapping = dir->i_mapping;
 194        struct page *page = read_mapping_page(mapping, n, NULL);
 195        if (!IS_ERR(page)) {
 196                kmap(page);
 197                if (!PageChecked(page))
 198                        ufs_check_page(page);
 199                if (PageError(page))
 200                        goto fail;
 201        }
 202        return page;
 203
 204fail:
 205        ufs_put_page(page);
 206        return ERR_PTR(-EIO);
 207}
 208
 209/*
 210 * Return the offset into page `page_nr' of the last valid
 211 * byte in that page, plus one.
 212 */
 213static unsigned
 214ufs_last_byte(struct inode *inode, unsigned long page_nr)
 215{
 216        unsigned last_byte = inode->i_size;
 217
 218        last_byte -= page_nr << PAGE_CACHE_SHIFT;
 219        if (last_byte > PAGE_CACHE_SIZE)
 220                last_byte = PAGE_CACHE_SIZE;
 221        return last_byte;
 222}
 223
 224static inline struct ufs_dir_entry *
 225ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
 226{
 227        return (struct ufs_dir_entry *)((char *)p +
 228                                        fs16_to_cpu(sb, p->d_reclen));
 229}
 230
 231struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
 232{
 233        struct page *page = ufs_get_page(dir, 0);
 234        struct ufs_dir_entry *de = NULL;
 235
 236        if (!IS_ERR(page)) {
 237                de = ufs_next_entry(dir->i_sb,
 238                                    (struct ufs_dir_entry *)page_address(page));
 239                *p = page;
 240        }
 241        return de;
 242}
 243
 244/*
 245 *      ufs_find_entry()
 246 *
 247 * finds an entry in the specified directory with the wanted name. It
 248 * returns the page in which the entry was found, and the entry itself
 249 * (as a parameter - res_dir). Page is returned mapped and unlocked.
 250 * Entry is guaranteed to be valid.
 251 */
 252struct ufs_dir_entry *ufs_find_entry(struct inode *dir, struct dentry *dentry,
 253                                     struct page **res_page)
 254{
 255        struct super_block *sb = dir->i_sb;
 256        const char *name = dentry->d_name.name;
 257        int namelen = dentry->d_name.len;
 258        unsigned reclen = UFS_DIR_REC_LEN(namelen);
 259        unsigned long start, n;
 260        unsigned long npages = ufs_dir_pages(dir);
 261        struct page *page = NULL;
 262        struct ufs_inode_info *ui = UFS_I(dir);
 263        struct ufs_dir_entry *de;
 264
 265        UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
 266
 267        if (npages == 0 || namelen > UFS_MAXNAMLEN)
 268                goto out;
 269
 270        /* OFFSET_CACHE */
 271        *res_page = NULL;
 272
 273        start = ui->i_dir_start_lookup;
 274
 275        if (start >= npages)
 276                start = 0;
 277        n = start;
 278        do {
 279                char *kaddr;
 280                page = ufs_get_page(dir, n);
 281                if (!IS_ERR(page)) {
 282                        kaddr = page_address(page);
 283                        de = (struct ufs_dir_entry *) kaddr;
 284                        kaddr += ufs_last_byte(dir, n) - reclen;
 285                        while ((char *) de <= kaddr) {
 286                                if (de->d_reclen == 0) {
 287                                        ufs_error(dir->i_sb, __FUNCTION__,
 288                                                  "zero-length directory entry");
 289                                        ufs_put_page(page);
 290                                        goto out;
 291                                }
 292                                if (ufs_match(sb, namelen, name, de))
 293                                        goto found;
 294                                de = ufs_next_entry(sb, de);
 295                        }
 296                        ufs_put_page(page);
 297                }
 298                if (++n >= npages)
 299                        n = 0;
 300        } while (n != start);
 301out:
 302        return NULL;
 303
 304found:
 305        *res_page = page;
 306        ui->i_dir_start_lookup = n;
 307        return de;
 308}
 309
 310/*
 311 *      Parent is locked.
 312 */
 313int ufs_add_link(struct dentry *dentry, struct inode *inode)
 314{
 315        struct inode *dir = dentry->d_parent->d_inode;
 316        const char *name = dentry->d_name.name;
 317        int namelen = dentry->d_name.len;
 318        struct super_block *sb = dir->i_sb;
 319        unsigned reclen = UFS_DIR_REC_LEN(namelen);
 320        const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
 321        unsigned short rec_len, name_len;
 322        struct page *page = NULL;
 323        struct ufs_dir_entry *de;
 324        unsigned long npages = ufs_dir_pages(dir);
 325        unsigned long n;
 326        char *kaddr;
 327        loff_t pos;
 328        int err;
 329
 330        UFSD("ENTER, name %s, namelen %u\n", name, namelen);
 331
 332        /*
 333         * We take care of directory expansion in the same loop.
 334         * This code plays outside i_size, so it locks the page
 335         * to protect that region.
 336         */
 337        for (n = 0; n <= npages; n++) {
 338                char *dir_end;
 339
 340                page = ufs_get_page(dir, n);
 341                err = PTR_ERR(page);
 342                if (IS_ERR(page))
 343                        goto out;
 344                lock_page(page);
 345                kaddr = page_address(page);
 346                dir_end = kaddr + ufs_last_byte(dir, n);
 347                de = (struct ufs_dir_entry *)kaddr;
 348                kaddr += PAGE_CACHE_SIZE - reclen;
 349                while ((char *)de <= kaddr) {
 350                        if ((char *)de == dir_end) {
 351                                /* We hit i_size */
 352                                name_len = 0;
 353                                rec_len = chunk_size;
 354                                de->d_reclen = cpu_to_fs16(sb, chunk_size);
 355                                de->d_ino = 0;
 356                                goto got_it;
 357                        }
 358                        if (de->d_reclen == 0) {
 359                                ufs_error(dir->i_sb, __FUNCTION__,
 360                                          "zero-length directory entry");
 361                                err = -EIO;
 362                                goto out_unlock;
 363                        }
 364                        err = -EEXIST;
 365                        if (ufs_match(sb, namelen, name, de))
 366                                goto out_unlock;
 367                        name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
 368                        rec_len = fs16_to_cpu(sb, de->d_reclen);
 369                        if (!de->d_ino && rec_len >= reclen)
 370                                goto got_it;
 371                        if (rec_len >= name_len + reclen)
 372                                goto got_it;
 373                        de = (struct ufs_dir_entry *) ((char *) de + rec_len);
 374                }
 375                unlock_page(page);
 376                ufs_put_page(page);
 377        }
 378        BUG();
 379        return -EINVAL;
 380
 381got_it:
 382        pos = page_offset(page) +
 383                        (char*)de - (char*)page_address(page);
 384        err = __ufs_write_begin(NULL, page->mapping, pos, rec_len,
 385                                AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
 386        if (err)
 387                goto out_unlock;
 388        if (de->d_ino) {
 389                struct ufs_dir_entry *de1 =
 390                        (struct ufs_dir_entry *) ((char *) de + name_len);
 391                de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len);
 392                de->d_reclen = cpu_to_fs16(sb, name_len);
 393
 394                de = de1;
 395        }
 396
 397        ufs_set_de_namlen(sb, de, namelen);
 398        memcpy(de->d_name, name, namelen + 1);
 399        de->d_ino = cpu_to_fs32(sb, inode->i_ino);
 400        ufs_set_de_type(sb, de, inode->i_mode);
 401
 402        err = ufs_commit_chunk(page, pos, rec_len);
 403        dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
 404
 405        mark_inode_dirty(dir);
 406        /* OFFSET_CACHE */
 407out_put:
 408        ufs_put_page(page);
 409out:
 410        return err;
 411out_unlock:
 412        unlock_page(page);
 413        goto out_put;
 414}
 415
 416static inline unsigned
 417ufs_validate_entry(struct super_block *sb, char *base,
 418                   unsigned offset, unsigned mask)
 419{
 420        struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
 421        struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
 422        while ((char*)p < (char*)de) {
 423                if (p->d_reclen == 0)
 424                        break;
 425                p = ufs_next_entry(sb, p);
 426        }
 427        return (char *)p - base;
 428}
 429
 430
 431/*
 432 * This is blatantly stolen from ext2fs
 433 */
 434static int
 435ufs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 436{
 437        loff_t pos = filp->f_pos;
 438        struct inode *inode = filp->f_path.dentry->d_inode;
 439        struct super_block *sb = inode->i_sb;
 440        unsigned int offset = pos & ~PAGE_CACHE_MASK;
 441        unsigned long n = pos >> PAGE_CACHE_SHIFT;
 442        unsigned long npages = ufs_dir_pages(inode);
 443        unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
 444        int need_revalidate = filp->f_version != inode->i_version;
 445        unsigned flags = UFS_SB(sb)->s_flags;
 446
 447        UFSD("BEGIN\n");
 448
 449        if (pos > inode->i_size - UFS_DIR_REC_LEN(1))
 450                return 0;
 451
 452        for ( ; n < npages; n++, offset = 0) {
 453                char *kaddr, *limit;
 454                struct ufs_dir_entry *de;
 455
 456                struct page *page = ufs_get_page(inode, n);
 457
 458                if (IS_ERR(page)) {
 459                        ufs_error(sb, __FUNCTION__,
 460                                  "bad page in #%lu",
 461                                  inode->i_ino);
 462                        filp->f_pos += PAGE_CACHE_SIZE - offset;
 463                        return -EIO;
 464                }
 465                kaddr = page_address(page);
 466                if (unlikely(need_revalidate)) {
 467                        if (offset) {
 468                                offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
 469                                filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
 470                        }
 471                        filp->f_version = inode->i_version;
 472                        need_revalidate = 0;
 473                }
 474                de = (struct ufs_dir_entry *)(kaddr+offset);
 475                limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1);
 476                for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) {
 477                        if (de->d_reclen == 0) {
 478                                ufs_error(sb, __FUNCTION__,
 479                                        "zero-length directory entry");
 480                                ufs_put_page(page);
 481                                return -EIO;
 482                        }
 483                        if (de->d_ino) {
 484                                int over;
 485                                unsigned char d_type = DT_UNKNOWN;
 486
 487                                offset = (char *)de - kaddr;
 488
 489                                UFSD("filldir(%s,%u)\n", de->d_name,
 490                                      fs32_to_cpu(sb, de->d_ino));
 491                                UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
 492
 493                                if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
 494                                        d_type = de->d_u.d_44.d_type;
 495
 496                                over = filldir(dirent, de->d_name,
 497                                               ufs_get_de_namlen(sb, de),
 498                                                (n<<PAGE_CACHE_SHIFT) | offset,
 499                                               fs32_to_cpu(sb, de->d_ino), d_type);
 500                                if (over) {
 501                                        ufs_put_page(page);
 502                                        return 0;
 503                                }
 504                        }
 505                        filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
 506                }
 507                ufs_put_page(page);
 508        }
 509        return 0;
 510}
 511
 512
 513/*
 514 * ufs_delete_entry deletes a directory entry by merging it with the
 515 * previous entry.
 516 */
 517int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
 518                     struct page * page)
 519{
 520        struct super_block *sb = inode->i_sb;
 521        struct address_space *mapping = page->mapping;
 522        char *kaddr = page_address(page);
 523        unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
 524        unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen);
 525        loff_t pos;
 526        struct ufs_dir_entry *pde = NULL;
 527        struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
 528        int err;
 529
 530        UFSD("ENTER\n");
 531
 532        UFSD("ino %u, reclen %u, namlen %u, name %s\n",
 533              fs32_to_cpu(sb, de->d_ino),
 534              fs16_to_cpu(sb, de->d_reclen),
 535              ufs_get_de_namlen(sb, de), de->d_name);
 536
 537        while ((char*)de < (char*)dir) {
 538                if (de->d_reclen == 0) {
 539                        ufs_error(inode->i_sb, __FUNCTION__,
 540                                  "zero-length directory entry");
 541                        err = -EIO;
 542                        goto out;
 543                }
 544                pde = de;
 545                de = ufs_next_entry(sb, de);
 546        }
 547        if (pde)
 548                from = (char*)pde - (char*)page_address(page);
 549
 550        pos = page_offset(page) + from;
 551        lock_page(page);
 552        err = __ufs_write_begin(NULL, mapping, pos, to - from,
 553                                AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
 554        BUG_ON(err);
 555        if (pde)
 556                pde->d_reclen = cpu_to_fs16(sb, to - from);
 557        dir->d_ino = 0;
 558        err = ufs_commit_chunk(page, pos, to - from);
 559        inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
 560        mark_inode_dirty(inode);
 561out:
 562        ufs_put_page(page);
 563        UFSD("EXIT\n");
 564        return err;
 565}
 566
 567int ufs_make_empty(struct inode * inode, struct inode *dir)
 568{
 569        struct super_block * sb = dir->i_sb;
 570        struct address_space *mapping = inode->i_mapping;
 571        struct page *page = grab_cache_page(mapping, 0);
 572        const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
 573        struct ufs_dir_entry * de;
 574        char *base;
 575        int err;
 576
 577        if (!page)
 578                return -ENOMEM;
 579
 580        err = __ufs_write_begin(NULL, mapping, 0, chunk_size,
 581                                AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
 582        if (err) {
 583                unlock_page(page);
 584                goto fail;
 585        }
 586
 587        kmap(page);
 588        base = (char*)page_address(page);
 589        memset(base, 0, PAGE_CACHE_SIZE);
 590
 591        de = (struct ufs_dir_entry *) base;
 592
 593        de->d_ino = cpu_to_fs32(sb, inode->i_ino);
 594        ufs_set_de_type(sb, de, inode->i_mode);
 595        ufs_set_de_namlen(sb, de, 1);
 596        de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
 597        strcpy (de->d_name, ".");
 598        de = (struct ufs_dir_entry *)
 599                ((char *)de + fs16_to_cpu(sb, de->d_reclen));
 600        de->d_ino = cpu_to_fs32(sb, dir->i_ino);
 601        ufs_set_de_type(sb, de, dir->i_mode);
 602        de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1));
 603        ufs_set_de_namlen(sb, de, 2);
 604        strcpy (de->d_name, "..");
 605        kunmap(page);
 606
 607        err = ufs_commit_chunk(page, 0, chunk_size);
 608fail:
 609        page_cache_release(page);
 610        return err;
 611}
 612
 613/*
 614 * routine to check that the specified directory is empty (for rmdir)
 615 */
 616int ufs_empty_dir(struct inode * inode)
 617{
 618        struct super_block *sb = inode->i_sb;
 619        struct page *page = NULL;
 620        unsigned long i, npages = ufs_dir_pages(inode);
 621
 622        for (i = 0; i < npages; i++) {
 623                char *kaddr;
 624                struct ufs_dir_entry *de;
 625                page = ufs_get_page(inode, i);
 626
 627                if (IS_ERR(page))
 628                        continue;
 629
 630                kaddr = page_address(page);
 631                de = (struct ufs_dir_entry *)kaddr;
 632                kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
 633
 634                while ((char *)de <= kaddr) {
 635                        if (de->d_reclen == 0) {
 636                                ufs_error(inode->i_sb, __FUNCTION__,
 637                                        "zero-length directory entry: "
 638                                        "kaddr=%p, de=%p\n", kaddr, de);
 639                                goto not_empty;
 640                        }
 641                        if (de->d_ino) {
 642                                u16 namelen=ufs_get_de_namlen(sb, de);
 643                                /* check for . and .. */
 644                                if (de->d_name[0] != '.')
 645                                        goto not_empty;
 646                                if (namelen > 2)
 647                                        goto not_empty;
 648                                if (namelen < 2) {
 649                                        if (inode->i_ino !=
 650                                            fs32_to_cpu(sb, de->d_ino))
 651                                                goto not_empty;
 652                                } else if (de->d_name[1] != '.')
 653                                        goto not_empty;
 654                        }
 655                        de = ufs_next_entry(sb, de);
 656                }
 657                ufs_put_page(page);
 658        }
 659        return 1;
 660
 661not_empty:
 662        ufs_put_page(page);
 663        return 0;
 664}
 665
 666const struct file_operations ufs_dir_operations = {
 667        .read           = generic_read_dir,
 668        .readdir        = ufs_readdir,
 669        .fsync          = file_fsync,
 670};
 671