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 16 #include <linux/time.h> 17 #include <linux/fs.h> 18 #include <linux/ufs_fs.h> 19 #include <linux/smp_lock.h> 20 #include <linux/buffer_head.h> 21 #include <linux/sched.h> 22 23 #include "swab.h" 24 #include "util.h" 25 26 #undef UFS_DIR_DEBUG 27 28 #ifdef UFS_DIR_DEBUG 29 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x; 30 #else 31 #define UFSD(x) 32 #endif 33 34 static int 35 ufs_check_dir_entry (const char *, struct inode *, struct ufs_dir_entry *, 36 struct buffer_head *, unsigned long); 37 38 39 /* 40 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure. 41 * 42 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller. 43 */ 44 static inline int ufs_match(struct super_block *sb, int len, 45 const char * const name, struct ufs_dir_entry * de) 46 { 47 if (len != ufs_get_de_namlen(sb, de)) 48 return 0; 49 if (!de->d_ino) 50 return 0; 51 return !memcmp(name, de->d_name, len); 52 } 53 54 /* 55 * This is blatantly stolen from ext2fs 56 */ 57 static int 58 ufs_readdir (struct file * filp, void * dirent, filldir_t filldir) 59 { 60 struct inode *inode = filp->f_dentry->d_inode; 61 int error = 0; 62 unsigned long offset, lblk; 63 int i, stored; 64 struct buffer_head * bh; 65 struct ufs_dir_entry * de; 66 struct super_block * sb; 67 int de_reclen; 68 unsigned flags; 69 u64 blk= 0L; 70 71 lock_kernel(); 72 73 sb = inode->i_sb; 74 flags = UFS_SB(sb)->s_flags; 75 76 UFSD(("ENTER, ino %lu f_pos %lu\n", inode->i_ino, (unsigned long) filp->f_pos)) 77 78 stored = 0; 79 bh = NULL; 80 offset = filp->f_pos & (sb->s_blocksize - 1); 81 82 while (!error && !stored && filp->f_pos < inode->i_size) { 83 lblk = (filp->f_pos) >> sb->s_blocksize_bits; 84 blk = ufs_frag_map(inode, lblk); 85 if (!blk || !(bh = sb_bread(sb, blk))) { 86 /* XXX - error - skip to the next block */ 87 printk("ufs_readdir: " 88 "dir inode %lu has a hole at offset %lu\n", 89 inode->i_ino, (unsigned long int)filp->f_pos); 90 filp->f_pos += sb->s_blocksize - offset; 91 continue; 92 } 93 94 revalidate: 95 /* If the dir block has changed since the last call to 96 * readdir(2), then we might be pointing to an invalid 97 * dirent right now. Scan from the start of the block 98 * to make sure. */ 99 if (filp->f_version != inode->i_version) { 100 for (i = 0; i < sb->s_blocksize && i < offset; ) { 101 de = (struct ufs_dir_entry *)(bh->b_data + i); 102 /* It's too expensive to do a full 103 * dirent test each time round this 104 * loop, but we do have to test at 105 * least that it is non-zero. A 106 * failure will be detected in the 107 * dirent test below. */ 108 de_reclen = fs16_to_cpu(sb, de->d_reclen); 109 if (de_reclen < 1) 110 break; 111 i += de_reclen; 112 } 113 offset = i; 114 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1)) 115 | offset; 116 filp->f_version = inode->i_version; 117 } 118 119 while (!error && filp->f_pos < inode->i_size 120 && offset < sb->s_blocksize) { 121 de = (struct ufs_dir_entry *) (bh->b_data + offset); 122 /* XXX - put in a real ufs_check_dir_entry() */ 123 if ((de->d_reclen == 0) || (ufs_get_de_namlen(sb, de) == 0)) { 124 filp->f_pos = (filp->f_pos & 125 (sb->s_blocksize - 1)) + 126 sb->s_blocksize; 127 brelse(bh); 128 unlock_kernel(); 129 return stored; 130 } 131 if (!ufs_check_dir_entry ("ufs_readdir", inode, de, 132 bh, offset)) { 133 /* On error, skip the f_pos to the 134 next block. */ 135 filp->f_pos = (filp->f_pos | 136 (sb->s_blocksize - 1)) + 137 1; 138 brelse (bh); 139 unlock_kernel(); 140 return stored; 141 } 142 offset += fs16_to_cpu(sb, de->d_reclen); 143 if (de->d_ino) { 144 /* We might block in the next section 145 * if the data destination is 146 * currently swapped out. So, use a 147 * version stamp to detect whether or 148 * not the directory has been modified 149 * during the copy operation. */ 150 unsigned long version = filp->f_version; 151 unsigned char d_type = DT_UNKNOWN; 152 153 UFSD(("filldir(%s,%u)\n", de->d_name, 154 fs32_to_cpu(sb, de->d_ino))) 155 UFSD(("namlen %u\n", ufs_get_de_namlen(sb, de))) 156 157 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) 158 d_type = de->d_u.d_44.d_type; 159 error = filldir(dirent, de->d_name, 160 ufs_get_de_namlen(sb, de), filp->f_pos, 161 fs32_to_cpu(sb, de->d_ino), d_type); 162 if (error) 163 break; 164 if (version != filp->f_version) 165 goto revalidate; 166 stored ++; 167 } 168 filp->f_pos += fs16_to_cpu(sb, de->d_reclen); 169 } 170 offset = 0; 171 brelse (bh); 172 } 173 unlock_kernel(); 174 return 0; 175 } 176 177 /* 178 * define how far ahead to read directories while searching them. 179 */ 180 #define NAMEI_RA_CHUNKS 2 181 #define NAMEI_RA_BLOCKS 4 182 #define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS) 183 #define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b)) 184 185 /* 186 * ufs_find_entry() 187 * 188 * finds an entry in the specified directory with the wanted name. It 189 * returns the cache buffer in which the entry was found, and the entry 190 * itself (as a parameter - res_bh). It does NOT read the inode of the 191 * entry - you'll have to do that yourself if you want to. 192 */ 193 struct ufs_dir_entry * ufs_find_entry (struct dentry *dentry, 194 struct buffer_head ** res_bh) 195 { 196 struct super_block * sb; 197 struct buffer_head * bh_use[NAMEI_RA_SIZE]; 198 struct buffer_head * bh_read[NAMEI_RA_SIZE]; 199 unsigned long offset; 200 int block, toread, i, err; 201 struct inode *dir = dentry->d_parent->d_inode; 202 const char *name = dentry->d_name.name; 203 int namelen = dentry->d_name.len; 204 205 UFSD(("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen)) 206 207 *res_bh = NULL; 208 209 sb = dir->i_sb; 210 211 if (namelen > UFS_MAXNAMLEN) 212 return NULL; 213 214 memset (bh_use, 0, sizeof (bh_use)); 215 toread = 0; 216 for (block = 0; block < NAMEI_RA_SIZE; ++block) { 217 struct buffer_head * bh; 218 219 if ((block << sb->s_blocksize_bits) >= dir->i_size) 220 break; 221 bh = ufs_getfrag (dir, block, 0, &err); 222 bh_use[block] = bh; 223 if (bh && !buffer_uptodate(bh)) 224 bh_read[toread++] = bh; 225 } 226 227 for (block = 0, offset = 0; offset < dir->i_size; block++) { 228 struct buffer_head * bh; 229 struct ufs_dir_entry * de; 230 char * dlimit; 231 232 if ((block % NAMEI_RA_BLOCKS) == 0 && toread) { 233 ll_rw_block (READ, toread, bh_read); 234 toread = 0; 235 } 236 bh = bh_use[block % NAMEI_RA_SIZE]; 237 if (!bh) { 238 ufs_error (sb, "ufs_find_entry", 239 "directory #%lu contains a hole at offset %lu", 240 dir->i_ino, offset); 241 offset += sb->s_blocksize; 242 continue; 243 } 244 wait_on_buffer (bh); 245 if (!buffer_uptodate(bh)) { 246 /* 247 * read error: all bets are off 248 */ 249 break; 250 } 251 252 de = (struct ufs_dir_entry *) bh->b_data; 253 dlimit = bh->b_data + sb->s_blocksize; 254 while ((char *) de < dlimit && offset < dir->i_size) { 255 /* this code is executed quadratically often */ 256 /* do minimal checking by hand */ 257 int de_len; 258 259 if ((char *) de + namelen <= dlimit && 260 ufs_match(sb, namelen, name, de)) { 261 /* found a match - 262 just to be sure, do a full check */ 263 if (!ufs_check_dir_entry("ufs_find_entry", 264 dir, de, bh, offset)) 265 goto failed; 266 for (i = 0; i < NAMEI_RA_SIZE; ++i) { 267 if (bh_use[i] != bh) 268 brelse (bh_use[i]); 269 } 270 *res_bh = bh; 271 return de; 272 } 273 /* prevent looping on a bad block */ 274 de_len = fs16_to_cpu(sb, de->d_reclen); 275 if (de_len <= 0) 276 goto failed; 277 offset += de_len; 278 de = (struct ufs_dir_entry *) ((char *) de + de_len); 279 } 280 281 brelse (bh); 282 if (((block + NAMEI_RA_SIZE) << sb->s_blocksize_bits ) >= 283 dir->i_size) 284 bh = NULL; 285 else 286 bh = ufs_getfrag (dir, block + NAMEI_RA_SIZE, 0, &err); 287 bh_use[block % NAMEI_RA_SIZE] = bh; 288 if (bh && !buffer_uptodate(bh)) 289 bh_read[toread++] = bh; 290 } 291 292 failed: 293 for (i = 0; i < NAMEI_RA_SIZE; ++i) brelse (bh_use[i]); 294 UFSD(("EXIT\n")) 295 return NULL; 296 } 297 298 static int 299 ufs_check_dir_entry (const char *function, struct inode *dir, 300 struct ufs_dir_entry *de, struct buffer_head *bh, 301 unsigned long offset) 302 { 303 struct super_block *sb = dir->i_sb; 304 const char *error_msg = NULL; 305 int rlen = fs16_to_cpu(sb, de->d_reclen); 306 307 if (rlen < UFS_DIR_REC_LEN(1)) 308 error_msg = "reclen is smaller than minimal"; 309 else if (rlen % 4 != 0) 310 error_msg = "reclen % 4 != 0"; 311 else if (rlen < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de))) 312 error_msg = "reclen is too small for namlen"; 313 else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize) 314 error_msg = "directory entry across blocks"; 315 else if (fs32_to_cpu(sb, de->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg * 316 UFS_SB(sb)->s_uspi->s_ncg)) 317 error_msg = "inode out of bounds"; 318 319 if (error_msg != NULL) 320 ufs_error (sb, function, "bad entry in directory #%lu, size %Lu: %s - " 321 "offset=%lu, inode=%lu, reclen=%d, namlen=%d", 322 dir->i_ino, dir->i_size, error_msg, offset, 323 (unsigned long)fs32_to_cpu(sb, de->d_ino), 324 rlen, ufs_get_de_namlen(sb, de)); 325 326 return (error_msg == NULL ? 1 : 0); 327 } 328 329 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct buffer_head **p) 330 { 331 int err; 332 struct buffer_head *bh = ufs_bread (dir, 0, 0, &err); 333 struct ufs_dir_entry *res = NULL; 334 335 if (bh) { 336 res = (struct ufs_dir_entry *) bh->b_data; 337 res = (struct ufs_dir_entry *)((char *)res + 338 fs16_to_cpu(dir->i_sb, res->d_reclen)); 339 } 340 *p = bh; 341 return res; 342 } 343 ino_t ufs_inode_by_name(struct inode * dir, struct dentry *dentry) 344 { 345 ino_t res = 0; 346 struct ufs_dir_entry * de; 347 struct buffer_head *bh; 348 349 de = ufs_find_entry (dentry, &bh); 350 if (de) { 351 res = fs32_to_cpu(dir->i_sb, de->d_ino); 352 brelse(bh); 353 } 354 return res; 355 } 356 357 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de, 358 struct buffer_head *bh, struct inode *inode) 359 { 360 dir->i_version++; 361 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino); 362 mark_buffer_dirty(bh); 363 if (IS_DIRSYNC(dir)) 364 sync_dirty_buffer(bh); 365 brelse (bh); 366 } 367 368 /* 369 * ufs_add_entry() 370 * 371 * adds a file entry to the specified directory, using the same 372 * semantics as ufs_find_entry(). It returns NULL if it failed. 373 */ 374 int ufs_add_link(struct dentry *dentry, struct inode *inode) 375 { 376 struct super_block * sb; 377 struct ufs_sb_private_info * uspi; 378 unsigned long offset; 379 unsigned fragoff; 380 unsigned short rec_len; 381 struct buffer_head * bh; 382 struct ufs_dir_entry * de, * de1; 383 struct inode *dir = dentry->d_parent->d_inode; 384 const char *name = dentry->d_name.name; 385 int namelen = dentry->d_name.len; 386 int err; 387 388 UFSD(("ENTER, name %s, namelen %u\n", name, namelen)) 389 390 sb = dir->i_sb; 391 uspi = UFS_SB(sb)->s_uspi; 392 393 if (!namelen) 394 return -EINVAL; 395 bh = ufs_bread (dir, 0, 0, &err); 396 if (!bh) 397 return err; 398 rec_len = UFS_DIR_REC_LEN(namelen); 399 offset = 0; 400 de = (struct ufs_dir_entry *) bh->b_data; 401 while (1) { 402 if ((char *)de >= UFS_SECTOR_SIZE + bh->b_data) { 403 fragoff = offset & ~uspi->s_fmask; 404 if (fragoff != 0 && fragoff != UFS_SECTOR_SIZE) 405 ufs_error (sb, "ufs_add_entry", "internal error" 406 " fragoff %u", fragoff); 407 if (!fragoff) { 408 brelse (bh); 409 bh = ufs_bread (dir, offset >> sb->s_blocksize_bits, 1, &err); 410 if (!bh) 411 return err; 412 } 413 if (dir->i_size <= offset) { 414 if (dir->i_size == 0) { 415 brelse(bh); 416 return -ENOENT; 417 } 418 de = (struct ufs_dir_entry *) (bh->b_data + fragoff); 419 de->d_ino = 0; 420 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE); 421 ufs_set_de_namlen(sb, de, 0); 422 dir->i_size = offset + UFS_SECTOR_SIZE; 423 mark_inode_dirty(dir); 424 } else { 425 de = (struct ufs_dir_entry *) bh->b_data; 426 } 427 } 428 if (!ufs_check_dir_entry ("ufs_add_entry", dir, de, bh, offset)) { 429 brelse (bh); 430 return -ENOENT; 431 } 432 if (ufs_match(sb, namelen, name, de)) { 433 brelse (bh); 434 return -EEXIST; 435 } 436 if (de->d_ino == 0 && fs16_to_cpu(sb, de->d_reclen) >= rec_len) 437 break; 438 439 if (fs16_to_cpu(sb, de->d_reclen) >= 440 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)) + rec_len) 441 break; 442 offset += fs16_to_cpu(sb, de->d_reclen); 443 de = (struct ufs_dir_entry *) ((char *) de + fs16_to_cpu(sb, de->d_reclen)); 444 } 445 446 if (de->d_ino) { 447 de1 = (struct ufs_dir_entry *) ((char *) de + 448 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de))); 449 de1->d_reclen = 450 cpu_to_fs16(sb, fs16_to_cpu(sb, de->d_reclen) - 451 UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de))); 452 de->d_reclen = 453 cpu_to_fs16(sb, UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de))); 454 de = de1; 455 } 456 de->d_ino = 0; 457 ufs_set_de_namlen(sb, de, namelen); 458 memcpy (de->d_name, name, namelen + 1); 459 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 460 ufs_set_de_type(sb, de, inode->i_mode); 461 mark_buffer_dirty(bh); 462 if (IS_DIRSYNC(dir)) 463 sync_dirty_buffer(bh); 464 brelse (bh); 465 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 466 dir->i_version++; 467 mark_inode_dirty(dir); 468 469 UFSD(("EXIT\n")) 470 return 0; 471 } 472 473 /* 474 * ufs_delete_entry deletes a directory entry by merging it with the 475 * previous entry. 476 */ 477 int ufs_delete_entry (struct inode * inode, struct ufs_dir_entry * dir, 478 struct buffer_head * bh ) 479 480 { 481 struct super_block * sb; 482 struct ufs_dir_entry * de, * pde; 483 unsigned i; 484 485 UFSD(("ENTER\n")) 486 487 sb = inode->i_sb; 488 i = 0; 489 pde = NULL; 490 de = (struct ufs_dir_entry *) bh->b_data; 491 492 UFSD(("ino %u, reclen %u, namlen %u, name %s\n", 493 fs32_to_cpu(sb, de->d_ino), 494 fs16to_cpu(sb, de->d_reclen), 495 ufs_get_de_namlen(sb, de), de->d_name)) 496 497 while (i < bh->b_size) { 498 if (!ufs_check_dir_entry ("ufs_delete_entry", inode, de, bh, i)) { 499 brelse(bh); 500 return -EIO; 501 } 502 if (de == dir) { 503 if (pde) 504 fs16_add(sb, &pde->d_reclen, 505 fs16_to_cpu(sb, dir->d_reclen)); 506 dir->d_ino = 0; 507 inode->i_version++; 508 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 509 mark_inode_dirty(inode); 510 mark_buffer_dirty(bh); 511 if (IS_DIRSYNC(inode)) 512 sync_dirty_buffer(bh); 513 brelse(bh); 514 UFSD(("EXIT\n")) 515 return 0; 516 } 517 i += fs16_to_cpu(sb, de->d_reclen); 518 if (i == UFS_SECTOR_SIZE) pde = NULL; 519 else pde = de; 520 de = (struct ufs_dir_entry *) 521 ((char *) de + fs16_to_cpu(sb, de->d_reclen)); 522 if (i == UFS_SECTOR_SIZE && de->d_reclen == 0) 523 break; 524 } 525 UFSD(("EXIT\n")) 526 brelse(bh); 527 return -ENOENT; 528 } 529 530 int ufs_make_empty(struct inode * inode, struct inode *dir) 531 { 532 struct super_block * sb = dir->i_sb; 533 struct buffer_head * dir_block; 534 struct ufs_dir_entry * de; 535 int err; 536 537 dir_block = ufs_bread (inode, 0, 1, &err); 538 if (!dir_block) 539 return err; 540 541 inode->i_blocks = sb->s_blocksize / UFS_SECTOR_SIZE; 542 de = (struct ufs_dir_entry *) dir_block->b_data; 543 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 544 ufs_set_de_type(sb, de, inode->i_mode); 545 ufs_set_de_namlen(sb, de, 1); 546 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); 547 strcpy (de->d_name, "."); 548 de = (struct ufs_dir_entry *) 549 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 550 de->d_ino = cpu_to_fs32(sb, dir->i_ino); 551 ufs_set_de_type(sb, de, dir->i_mode); 552 de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE - UFS_DIR_REC_LEN(1)); 553 ufs_set_de_namlen(sb, de, 2); 554 strcpy (de->d_name, ".."); 555 mark_buffer_dirty(dir_block); 556 brelse (dir_block); 557 mark_inode_dirty(inode); 558 return 0; 559 } 560 561 /* 562 * routine to check that the specified directory is empty (for rmdir) 563 */ 564 int ufs_empty_dir (struct inode * inode) 565 { 566 struct super_block * sb; 567 unsigned long offset; 568 struct buffer_head * bh; 569 struct ufs_dir_entry * de, * de1; 570 int err; 571 572 sb = inode->i_sb; 573 574 if (inode->i_size < UFS_DIR_REC_LEN(1) + UFS_DIR_REC_LEN(2) || 575 !(bh = ufs_bread (inode, 0, 0, &err))) { 576 ufs_warning (inode->i_sb, "empty_dir", 577 "bad directory (dir #%lu) - no data block", 578 inode->i_ino); 579 return 1; 580 } 581 de = (struct ufs_dir_entry *) bh->b_data; 582 de1 = (struct ufs_dir_entry *) 583 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 584 if (fs32_to_cpu(sb, de->d_ino) != inode->i_ino || de1->d_ino == 0 || 585 strcmp (".", de->d_name) || strcmp ("..", de1->d_name)) { 586 ufs_warning (inode->i_sb, "empty_dir", 587 "bad directory (dir #%lu) - no `.' or `..'", 588 inode->i_ino); 589 return 1; 590 } 591 offset = fs16_to_cpu(sb, de->d_reclen) + fs16_to_cpu(sb, de1->d_reclen); 592 de = (struct ufs_dir_entry *) 593 ((char *)de1 + fs16_to_cpu(sb, de1->d_reclen)); 594 while (offset < inode->i_size ) { 595 if (!bh || (void *) de >= (void *) (bh->b_data + sb->s_blocksize)) { 596 brelse (bh); 597 bh = ufs_bread (inode, offset >> sb->s_blocksize_bits, 1, &err); 598 if (!bh) { 599 ufs_error (sb, "empty_dir", 600 "directory #%lu contains a hole at offset %lu", 601 inode->i_ino, offset); 602 offset += sb->s_blocksize; 603 continue; 604 } 605 de = (struct ufs_dir_entry *) bh->b_data; 606 } 607 if (!ufs_check_dir_entry ("empty_dir", inode, de, bh, offset)) { 608 brelse (bh); 609 return 1; 610 } 611 if (de->d_ino) { 612 brelse (bh); 613 return 0; 614 } 615 offset += fs16_to_cpu(sb, de->d_reclen); 616 de = (struct ufs_dir_entry *) 617 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 618 } 619 brelse (bh); 620 return 1; 621 } 622 623 struct file_operations ufs_dir_operations = { 624 .read = generic_read_dir, 625 .readdir = ufs_readdir, 626 .fsync = file_fsync, 627 }; 628