fs/exofs/dir.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com)
   4  * Copyright (C) 2008, 2009
   5  * Boaz Harrosh <bharrosh@panasas.com>
   6  *
   7  * Copyrights for code taken from ext2:
   8  *     Copyright (C) 1992, 1993, 1994, 1995
   9  *     Remy Card (card@masi.ibp.fr)
  10  *     Laboratoire MASI - Institut Blaise Pascal
  11  *     Universite Pierre et Marie Curie (Paris VI)
  12  *     from
  13  *     linux/fs/minix/inode.c
  14  *     Copyright (C) 1991, 1992  Linus Torvalds
  15  *
  16  * This file is part of exofs.
  17  *
  18  * exofs is free software; you can redistribute it and/or modify
  19  * it under the terms of the GNU General Public License as published by
  20  * the Free Software Foundation.  Since it is based on ext2, and the only
  21  * valid version of GPL for the Linux kernel is version 2, the only valid
  22  * version of GPL for exofs is version 2.
  23  *
  24  * exofs is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  * GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with exofs; if not, write to the Free Software
  31  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  32  */
  33
  34 #include "exofs.h"
  35
  36 static inline unsigned exofs_chunk_size(struct inode *inode)
  37 {
  38         return inode->i_sb->s_blocksize;
  39 }
  40
  41 static inline void exofs_put_page(struct page *page)
  42 {
  43         kunmap(page);
  44         page_cache_release(page);
  45 }
  46
  47 /* Accesses dir's inode->i_size must be called under inode lock */
  48 static inline unsigned long dir_pages(struct inode *inode)
  49 {
  50         return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
  51 }
  52
  53 static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
  54 {
  55         loff_t last_byte = inode->i_size;
  56
  57         last_byte -= page_nr << PAGE_CACHE_SHIFT;
  58         if (last_byte > PAGE_CACHE_SIZE)
  59                 last_byte = PAGE_CACHE_SIZE;
  60         return last_byte;
  61 }
  62
  63 static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
  64 {
  65         struct address_space *mapping = page->mapping;
  66         struct inode *dir = mapping->host;
  67         int err = 0;
  68
  69         dir->i_version++;
  70
  71         if (!PageUptodate(page))
  72                 SetPageUptodate(page);
  73
  74         if (pos+len > dir->i_size) {
  75                 i_size_write(dir, pos+len);
  76                 mark_inode_dirty(dir);
  77         }
  78         set_page_dirty(page);
  79
  80         if (IS_DIRSYNC(dir))
  81                 err = write_one_page(page, 1);
  82         else
  83                 unlock_page(page);
  84
  85         return err;
  86 }
  87
  88 static void exofs_check_page(struct page *page)
  89 {
  90         struct inode *dir = page->mapping->host;
  91         unsigned chunk_size = exofs_chunk_size(dir);
  92         char *kaddr = page_address(page);
  93         unsigned offs, rec_len;
  94         unsigned limit = PAGE_CACHE_SIZE;
  95         struct exofs_dir_entry *p;
  96         char *error;
  97
  98         /* if the page is the last one in the directory */
  99         if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
 100                 limit = dir->i_size & ~PAGE_CACHE_MASK;
 101                 if (limit & (chunk_size - 1))
 102                         goto Ebadsize;
 103                 if (!limit)
 104                         goto out;
 105         }
 106         for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
 107                 p = (struct exofs_dir_entry *)(kaddr + offs);
 108                 rec_len = le16_to_cpu(p->rec_len);
 109
 110                 if (rec_len < EXOFS_DIR_REC_LEN(1))
 111                         goto Eshort;
 112                 if (rec_len & 3)
 113                         goto Ealign;
 114                 if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
 115                         goto Enamelen;
 116                 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
 117                         goto Espan;
 118         }
 119         if (offs != limit)
 120                 goto Eend;
 121 out:
 122         SetPageChecked(page);
 123         return;
 124
 125 Ebadsize:
 126         EXOFS_ERR("ERROR [exofs_check_page]: "
 127                 "size of directory #%lu is not a multiple of chunk size",
 128                 dir->i_ino
 129         );
 130         goto fail;
 131 Eshort:
 132         error = "rec_len is smaller than minimal";
 133         goto bad_entry;
 134 Ealign:
 135         error = "unaligned directory entry";
 136         goto bad_entry;
 137 Enamelen:
 138         error = "rec_len is too small for name_len";
 139         goto bad_entry;
 140 Espan:
 141         error = "directory entry across blocks";
 142         goto bad_entry;
 143 bad_entry:
 144         EXOFS_ERR(
 145                 "ERROR [exofs_check_page]: bad entry in directory #%lu: %s - "
 146                 "offset=%lu, inode=%llu, rec_len=%d, name_len=%d",
 147                 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
 148                 _LLU(le64_to_cpu(p->inode_no)),
 149                 rec_len, p->name_len);
 150         goto fail;
 151 Eend:
 152         p = (struct exofs_dir_entry *)(kaddr + offs);
 153         EXOFS_ERR("ERROR [exofs_check_page]: "
 154                 "entry in directory #%lu spans the page boundary"
 155                 "offset=%lu, inode=%llu",
 156                 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
 157                 _LLU(le64_to_cpu(p->inode_no)));
 158 fail:
 159         SetPageChecked(page);
 160         SetPageError(page);
 161 }
 162
 163 static struct page *exofs_get_page(struct inode *dir, unsigned long n)
 164 {
 165         struct address_space *mapping = dir->i_mapping;
 166         struct page *page = read_mapping_page(mapping, n, NULL);
 167
 168         if (!IS_ERR(page)) {
 169                 kmap(page);
 170                 if (!PageChecked(page))
 171                         exofs_check_page(page);
 172                 if (PageError(page))
 173                         goto fail;
 174         }
 175         return page;
 176
 177 fail:
 178         exofs_put_page(page);
 179         return ERR_PTR(-EIO);
 180 }
 181
 182 static inline int exofs_match(int len, const unsigned char *name,
 183                                         struct exofs_dir_entry *de)
 184 {
 185         if (len != de->name_len)
 186                 return 0;
 187         if (!de->inode_no)
 188                 return 0;
 189         return !memcmp(name, de->name, len);
 190 }
 191
 192 static inline
 193 struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
 194 {
 195         return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
 196 }
 197
 198 static inline unsigned
 199 exofs_validate_entry(char *base, unsigned offset, unsigned mask)
 200 {
 201         struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
 202         struct exofs_dir_entry *p =
 203                         (struct exofs_dir_entry *)(base + (offset&mask));
 204         while ((char *)p < (char *)de) {
 205                 if (p->rec_len == 0)
 206                         break;
 207                 p = exofs_next_entry(p);
 208         }
 209         return (char *)p - base;
 210 }
 211
 212 static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
 213         [EXOFS_FT_UNKNOWN]      = DT_UNKNOWN,
 214         [EXOFS_FT_REG_FILE]     = DT_REG,
 215         [EXOFS_FT_DIR]          = DT_DIR,
 216         [EXOFS_FT_CHRDEV]       = DT_CHR,
 217         [EXOFS_FT_BLKDEV]       = DT_BLK,
 218         [EXOFS_FT_FIFO]         = DT_FIFO,
 219         [EXOFS_FT_SOCK]         = DT_SOCK,
 220         [EXOFS_FT_SYMLINK]      = DT_LNK,
 221 };
 222
 223 #define S_SHIFT 12
 224 static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
 225         [S_IFREG >> S_SHIFT]    = EXOFS_FT_REG_FILE,
 226         [S_IFDIR >> S_SHIFT]    = EXOFS_FT_DIR,
 227         [S_IFCHR >> S_SHIFT]    = EXOFS_FT_CHRDEV,
 228         [S_IFBLK >> S_SHIFT]    = EXOFS_FT_BLKDEV,
 229         [S_IFIFO >> S_SHIFT]    = EXOFS_FT_FIFO,
 230         [S_IFSOCK >> S_SHIFT]   = EXOFS_FT_SOCK,
 231         [S_IFLNK >> S_SHIFT]    = EXOFS_FT_SYMLINK,
 232 };
 233
 234 static inline
 235 void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
 236 {
 237         mode_t mode = inode->i_mode;
 238         de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
 239 }
 240
 241 static int
 242 exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 243 {
 244         loff_t pos = filp->f_pos;
 245         struct inode *inode = filp->f_path.dentry->d_inode;
 246         unsigned int offset = pos & ~PAGE_CACHE_MASK;
 247         unsigned long n = pos >> PAGE_CACHE_SHIFT;
 248         unsigned long npages = dir_pages(inode);
 249         unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
 250         unsigned char *types = NULL;
 251         int need_revalidate = (filp->f_version != inode->i_version);
 252
 253         if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
 254                 return 0;
 255
 256         types = exofs_filetype_table;
 257
 258         for ( ; n < npages; n++, offset = 0) {
 259                 char *kaddr, *limit;
 260                 struct exofs_dir_entry *de;
 261                 struct page *page = exofs_get_page(inode, n);
 262
 263                 if (IS_ERR(page)) {
 264                         EXOFS_ERR("ERROR: "
 265                                    "bad page in #%lu",
 266                                    inode->i_ino);
 267                         filp->f_pos += PAGE_CACHE_SIZE - offset;
 268                         return PTR_ERR(page);
 269                 }
 270                 kaddr = page_address(page);
 271                 if (unlikely(need_revalidate)) {
 272                         if (offset) {
 273                                 offset = exofs_validate_entry(kaddr, offset,
 274                                                                 chunk_mask);
 275                                 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
 276                         }
 277                         filp->f_version = inode->i_version;
 278                         need_revalidate = 0;
 279                 }
 280                 de = (struct exofs_dir_entry *)(kaddr + offset);
 281                 limit = kaddr + exofs_last_byte(inode, n) -
 282                                                         EXOFS_DIR_REC_LEN(1);
 283                 for (; (char *)de <= limit; de = exofs_next_entry(de)) {
 284                         if (de->rec_len == 0) {
 285                                 EXOFS_ERR("ERROR: "
 286                                         "zero-length directory entry");
 287                                 exofs_put_page(page);
 288                                 return -EIO;
 289                         }
 290                         if (de->inode_no) {
 291                                 int over;
 292                                 unsigned char d_type = DT_UNKNOWN;
 293
 294                                 if (types && de->file_type < EXOFS_FT_MAX)
 295                                         d_type = types[de->file_type];
 296
 297                                 offset = (char *)de - kaddr;
 298                                 over = filldir(dirent, de->name, de->name_len,
 299                                                 (n<<PAGE_CACHE_SHIFT) | offset,
 300                                                 le64_to_cpu(de->inode_no),
 301                                                 d_type);
 302                                 if (over) {
 303                                         exofs_put_page(page);
 304                                         return 0;
 305                                 }
 306                         }
 307                         filp->f_pos += le16_to_cpu(de->rec_len);
 308                 }
 309                 exofs_put_page(page);
 310         }
 311
 312         return 0;
 313 }
 314
 315 struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
 316                         struct dentry *dentry, struct page **res_page)
 317 {
 318         const unsigned char *name = dentry->d_name.name;
 319         int namelen = dentry->d_name.len;
 320         unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
 321         unsigned long start, n;
 322         unsigned long npages = dir_pages(dir);
 323         struct page *page = NULL;
 324         struct exofs_i_info *oi = exofs_i(dir);
 325         struct exofs_dir_entry *de;
 326
 327         if (npages == 0)
 328                 goto out;
 329
 330         *res_page = NULL;
 331
 332         start = oi->i_dir_start_lookup;
 333         if (start >= npages)
 334                 start = 0;
 335         n = start;
 336         do {
 337                 char *kaddr;
 338                 page = exofs_get_page(dir, n);
 339                 if (!IS_ERR(page)) {
 340                         kaddr = page_address(page);
 341                         de = (struct exofs_dir_entry *) kaddr;
 342                         kaddr += exofs_last_byte(dir, n) - reclen;
 343                         while ((char *) de <= kaddr) {
 344                                 if (de->rec_len == 0) {
 345                                         EXOFS_ERR(
 346                                                 "ERROR: exofs_find_entry: "
 347                                                 "zero-length directory entry");
 348                                         exofs_put_page(page);
 349                                         goto out;
 350                                 }
 351                                 if (exofs_match(namelen, name, de))
 352                                         goto found;
 353                                 de = exofs_next_entry(de);
 354                         }
 355                         exofs_put_page(page);
 356                 }
 357                 if (++n >= npages)
 358                         n = 0;
 359         } while (n != start);
 360 out:
 361         return NULL;
 362
 363 found:
 364         *res_page = page;
 365         oi->i_dir_start_lookup = n;
 366         return de;
 367 }
 368
 369 struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
 370 {
 371         struct page *page = exofs_get_page(dir, 0);
 372         struct exofs_dir_entry *de = NULL;
 373
 374         if (!IS_ERR(page)) {
 375                 de = exofs_next_entry(
 376                                 (struct exofs_dir_entry *)page_address(page));
 377                 *p = page;
 378         }
 379         return de;
 380 }
 381
 382 ino_t exofs_parent_ino(struct dentry *child)
 383 {
 384         struct page *page;
 385         struct exofs_dir_entry *de;
 386         ino_t ino;
 387
 388         de = exofs_dotdot(child->d_inode, &page);
 389         if (!de)
 390                 return 0;
 391
 392         ino = le64_to_cpu(de->inode_no);
 393         exofs_put_page(page);
 394         return ino;
 395 }
 396
 397 ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
 398 {
 399         ino_t res = 0;
 400         struct exofs_dir_entry *de;
 401         struct page *page;
 402
 403         de = exofs_find_entry(dir, dentry, &page);
 404         if (de) {
 405                 res = le64_to_cpu(de->inode_no);
 406                 exofs_put_page(page);
 407         }
 408         return res;
 409 }
 410
 411 int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
 412                         struct page *page, struct inode *inode)
 413 {
 414         loff_t pos = page_offset(page) +
 415                         (char *) de - (char *) page_address(page);
 416         unsigned len = le16_to_cpu(de->rec_len);
 417         int err;
 418
 419         lock_page(page);
 420         err = exofs_write_begin(NULL, page->mapping, pos, len,
 421                                 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
 422         if (err)
 423                 EXOFS_ERR("exofs_set_link: exofs_write_begin FAILD => %d\n",
 424                           err);
 425
 426         de->inode_no = cpu_to_le64(inode->i_ino);
 427         exofs_set_de_type(de, inode);
 428         if (likely(!err))
 429                 err = exofs_commit_chunk(page, pos, len);
 430         exofs_put_page(page);
 431         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 432         mark_inode_dirty(dir);
 433         return err;
 434 }
 435
 436 int exofs_add_link(struct dentry *dentry, struct inode *inode)
 437 {
 438         struct inode *dir = dentry->d_parent->d_inode;
 439         const unsigned char *name = dentry->d_name.name;
 440         int namelen = dentry->d_name.len;
 441         unsigned chunk_size = exofs_chunk_size(dir);
 442         unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
 443         unsigned short rec_len, name_len;
 444         struct page *page = NULL;
 445         struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
 446         struct exofs_dir_entry *de;
 447         unsigned long npages = dir_pages(dir);
 448         unsigned long n;
 449         char *kaddr;
 450         loff_t pos;
 451         int err;
 452
 453         for (n = 0; n <= npages; n++) {
 454                 char *dir_end;
 455
 456                 page = exofs_get_page(dir, n);
 457                 err = PTR_ERR(page);
 458                 if (IS_ERR(page))
 459                         goto out;
 460                 lock_page(page);
 461                 kaddr = page_address(page);
 462                 dir_end = kaddr + exofs_last_byte(dir, n);
 463                 de = (struct exofs_dir_entry *)kaddr;
 464                 kaddr += PAGE_CACHE_SIZE - reclen;
 465                 while ((char *)de <= kaddr) {
 466                         if ((char *)de == dir_end) {
 467                                 name_len = 0;
 468                                 rec_len = chunk_size;
 469                                 de->rec_len = cpu_to_le16(chunk_size);
 470                                 de->inode_no = 0;
 471                                 goto got_it;
 472                         }
 473                         if (de->rec_len == 0) {
 474                                 EXOFS_ERR("ERROR: exofs_add_link: "
 475                                         "zero-length directory entry");
 476                                 err = -EIO;
 477                                 goto out_unlock;
 478                         }
 479                         err = -EEXIST;
 480                         if (exofs_match(namelen, name, de))
 481                                 goto out_unlock;
 482                         name_len = EXOFS_DIR_REC_LEN(de->name_len);
 483                         rec_len = le16_to_cpu(de->rec_len);
 484                         if (!de->inode_no && rec_len >= reclen)
 485                                 goto got_it;
 486                         if (rec_len >= name_len + reclen)
 487                                 goto got_it;
 488                         de = (struct exofs_dir_entry *) ((char *) de + rec_len);
 489                 }
 490                 unlock_page(page);
 491                 exofs_put_page(page);
 492         }
 493
 494         EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%p", dentry, inode);
 495         return -EINVAL;
 496
 497 got_it:
 498         pos = page_offset(page) +
 499                 (char *)de - (char *)page_address(page);
 500         err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
 501                                                         &page, NULL);
 502         if (err)
 503                 goto out_unlock;
 504         if (de->inode_no) {
 505                 struct exofs_dir_entry *de1 =
 506                         (struct exofs_dir_entry *)((char *)de + name_len);
 507                 de1->rec_len = cpu_to_le16(rec_len - name_len);
 508                 de->rec_len = cpu_to_le16(name_len);
 509                 de = de1;
 510         }
 511         de->name_len = namelen;
 512         memcpy(de->name, name, namelen);
 513         de->inode_no = cpu_to_le64(inode->i_ino);
 514         exofs_set_de_type(de, inode);
 515         err = exofs_commit_chunk(page, pos, rec_len);
 516         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
 517         mark_inode_dirty(dir);
 518         sbi->s_numfiles++;
 519
 520 out_put:
 521         exofs_put_page(page);
 522 out:
 523         return err;
 524 out_unlock:
 525         unlock_page(page);
 526         goto out_put;
 527 }
 528
 529 int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
 530 {
 531         struct address_space *mapping = page->mapping;
 532         struct inode *inode = mapping->host;
 533         struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
 534         char *kaddr = page_address(page);
 535         unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
 536         unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
 537         loff_t pos;
 538         struct exofs_dir_entry *pde = NULL;
 539         struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
 540         int err;
 541
 542         while (de < dir) {
 543                 if (de->rec_len == 0) {
 544                         EXOFS_ERR("ERROR: exofs_delete_entry:"
 545                                 "zero-length directory entry");
 546                         err = -EIO;
 547                         goto out;
 548                 }
 549                 pde = de;
 550                 de = exofs_next_entry(de);
 551         }
 552         if (pde)
 553                 from = (char *)pde - (char *)page_address(page);
 554         pos = page_offset(page) + from;
 555         lock_page(page);
 556         err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
 557                                                         &page, NULL);
 558         if (err)
 559                 EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILD => %d\n",
 560                           err);
 561         if (pde)
 562                 pde->rec_len = cpu_to_le16(to - from);
 563         dir->inode_no = 0;
 564         if (likely(!err))
 565                 err = exofs_commit_chunk(page, pos, to - from);
 566         inode->i_ctime = inode->i_mtime = CURRENT_TIME;
 567         mark_inode_dirty(inode);
 568         sbi->s_numfiles--;
 569 out:
 570         exofs_put_page(page);
 571         return err;
 572 }
 573
 574 /* kept aligned on 4 bytes */
 575 #define THIS_DIR ".\0\0"
 576 #define PARENT_DIR "..\0"
 577
 578 int exofs_make_empty(struct inode *inode, struct inode *parent)
 579 {
 580         struct address_space *mapping = inode->i_mapping;
 581         struct page *page = grab_cache_page(mapping, 0);
 582         unsigned chunk_size = exofs_chunk_size(inode);
 583         struct exofs_dir_entry *de;
 584         int err;
 585         void *kaddr;
 586
 587         if (!page)
 588                 return -ENOMEM;
 589
 590         err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
 591                                                         &page, NULL);
 592         if (err) {
 593                 unlock_page(page);
 594                 goto fail;
 595         }
 596
 597         kaddr = kmap_atomic(page, KM_USER0);
 598         de = (struct exofs_dir_entry *)kaddr;
 599         de->name_len = 1;
 600         de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
 601         memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
 602         de->inode_no = cpu_to_le64(inode->i_ino);
 603         exofs_set_de_type(de, inode);
 604
 605         de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
 606         de->name_len = 2;
 607         de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
 608         de->inode_no = cpu_to_le64(parent->i_ino);
 609         memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
 610         exofs_set_de_type(de, inode);
 611         kunmap_atomic(kaddr, KM_USER0);
 612         err = exofs_commit_chunk(page, 0, chunk_size);
 613 fail:
 614         page_cache_release(page);
 615         return err;
 616 }
 617
 618 int exofs_empty_dir(struct inode *inode)
 619 {
 620         struct page *page = NULL;
 621         unsigned long i, npages = dir_pages(inode);
 622
 623         for (i = 0; i < npages; i++) {
 624                 char *kaddr;
 625                 struct exofs_dir_entry *de;
 626                 page = exofs_get_page(inode, i);
 627
 628                 if (IS_ERR(page))
 629                         continue;
 630
 631                 kaddr = page_address(page);
 632                 de = (struct exofs_dir_entry *)kaddr;
 633                 kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
 634
 635                 while ((char *)de <= kaddr) {
 636                         if (de->rec_len == 0) {
 637                                 EXOFS_ERR("ERROR: exofs_empty_dir: "
 638                                           "zero-length directory entry"
 639                                           "kaddr=%p, de=%p\n", kaddr, de);
 640                                 goto not_empty;
 641                         }
 642                         if (de->inode_no != 0) {
 643                                 /* check for . and .. */
 644                                 if (de->name[0] != '.')
 645                                         goto not_empty;
 646                                 if (de->name_len > 2)
 647                                         goto not_empty;
 648                                 if (de->name_len < 2) {
 649                                         if (le64_to_cpu(de->inode_no) !=
 650                                             inode->i_ino)
 651                                                 goto not_empty;
 652                                 } else if (de->name[1] != '.')
 653                                         goto not_empty;
 654                         }
 655                         de = exofs_next_entry(de);
 656                 }
 657                 exofs_put_page(page);
 658         }
 659         return 1;
 660
 661 not_empty:
 662         exofs_put_page(page);
 663         return 0;
 664 }
 665
 666 const struct file_operations exofs_dir_operations = {
 667         .llseek         = generic_file_llseek,
 668         .read           = generic_read_dir,
 669         .readdir        = exofs_readdir,
 670 };