1 /* 2 * linux/fs/sysv/inode.c 3 * 4 * minix/inode.c 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 * 7 * xenix/inode.c 8 * Copyright (C) 1992 Doug Evans 9 * 10 * coh/inode.c 11 * Copyright (C) 1993 Pascal Haible, Bruno Haible 12 * 13 * sysv/inode.c 14 * Copyright (C) 1993 Paul B. Monday 15 * 16 * sysv/inode.c 17 * Copyright (C) 1993 Bruno Haible 18 * Copyright (C) 1997, 1998 Krzysztof G. Baranowski 19 * 20 * This file contains code for read/parsing the superblock. 21 */ 22 23 #include <linux/module.h> 24 #include <linux/init.h> 25 #include <linux/slab.h> 26 #include <linux/buffer_head.h> 27 #include "sysv.h" 28 29 /* 30 * The following functions try to recognize specific filesystems. 31 * 32 * We recognize: 33 * - Xenix FS by its magic number. 34 * - SystemV FS by its magic number. 35 * - Coherent FS by its funny fname/fpack field. 36 * - SCO AFS by s_nfree == 0xffff 37 * - V7 FS has no distinguishing features. 38 * 39 * We discriminate among SystemV4 and SystemV2 FS by the assumption that 40 * the time stamp is not < 01-01-1980. 41 */ 42 43 enum { 44 JAN_1_1980 = (10*365 + 2) * 24 * 60 * 60 45 }; 46 47 static void detected_xenix(struct sysv_sb_info *sbi, unsigned *max_links) 48 { 49 struct buffer_head *bh1 = sbi->s_bh1; 50 struct buffer_head *bh2 = sbi->s_bh2; 51 struct xenix_super_block * sbd1; 52 struct xenix_super_block * sbd2; 53 54 if (bh1 != bh2) 55 sbd1 = sbd2 = (struct xenix_super_block *) bh1->b_data; 56 else { 57 /* block size = 512, so bh1 != bh2 */ 58 sbd1 = (struct xenix_super_block *) bh1->b_data; 59 sbd2 = (struct xenix_super_block *) (bh2->b_data - 512); 60 } 61 62 *max_links = XENIX_LINK_MAX; 63 sbi->s_fic_size = XENIX_NICINOD; 64 sbi->s_flc_size = XENIX_NICFREE; 65 sbi->s_sbd1 = (char *)sbd1; 66 sbi->s_sbd2 = (char *)sbd2; 67 sbi->s_sb_fic_count = &sbd1->s_ninode; 68 sbi->s_sb_fic_inodes = &sbd1->s_inode[0]; 69 sbi->s_sb_total_free_inodes = &sbd2->s_tinode; 70 sbi->s_bcache_count = &sbd1->s_nfree; 71 sbi->s_bcache = &sbd1->s_free[0]; 72 sbi->s_free_blocks = &sbd2->s_tfree; 73 sbi->s_sb_time = &sbd2->s_time; 74 sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd1->s_isize); 75 sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize); 76 } 77 78 static void detected_sysv4(struct sysv_sb_info *sbi, unsigned *max_links) 79 { 80 struct sysv4_super_block * sbd; 81 struct buffer_head *bh1 = sbi->s_bh1; 82 struct buffer_head *bh2 = sbi->s_bh2; 83 84 if (bh1 == bh2) 85 sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2); 86 else 87 sbd = (struct sysv4_super_block *) bh2->b_data; 88 89 *max_links = SYSV_LINK_MAX; 90 sbi->s_fic_size = SYSV_NICINOD; 91 sbi->s_flc_size = SYSV_NICFREE; 92 sbi->s_sbd1 = (char *)sbd; 93 sbi->s_sbd2 = (char *)sbd; 94 sbi->s_sb_fic_count = &sbd->s_ninode; 95 sbi->s_sb_fic_inodes = &sbd->s_inode[0]; 96 sbi->s_sb_total_free_inodes = &sbd->s_tinode; 97 sbi->s_bcache_count = &sbd->s_nfree; 98 sbi->s_bcache = &sbd->s_free[0]; 99 sbi->s_free_blocks = &sbd->s_tfree; 100 sbi->s_sb_time = &sbd->s_time; 101 sbi->s_sb_state = &sbd->s_state; 102 sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); 103 sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); 104 } 105 106 static void detected_sysv2(struct sysv_sb_info *sbi, unsigned *max_links) 107 { 108 struct sysv2_super_block *sbd; 109 struct buffer_head *bh1 = sbi->s_bh1; 110 struct buffer_head *bh2 = sbi->s_bh2; 111 112 if (bh1 == bh2) 113 sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2); 114 else 115 sbd = (struct sysv2_super_block *) bh2->b_data; 116 117 *max_links = SYSV_LINK_MAX; 118 sbi->s_fic_size = SYSV_NICINOD; 119 sbi->s_flc_size = SYSV_NICFREE; 120 sbi->s_sbd1 = (char *)sbd; 121 sbi->s_sbd2 = (char *)sbd; 122 sbi->s_sb_fic_count = &sbd->s_ninode; 123 sbi->s_sb_fic_inodes = &sbd->s_inode[0]; 124 sbi->s_sb_total_free_inodes = &sbd->s_tinode; 125 sbi->s_bcache_count = &sbd->s_nfree; 126 sbi->s_bcache = &sbd->s_free[0]; 127 sbi->s_free_blocks = &sbd->s_tfree; 128 sbi->s_sb_time = &sbd->s_time; 129 sbi->s_sb_state = &sbd->s_state; 130 sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); 131 sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); 132 } 133 134 static void detected_coherent(struct sysv_sb_info *sbi, unsigned *max_links) 135 { 136 struct coh_super_block * sbd; 137 struct buffer_head *bh1 = sbi->s_bh1; 138 139 sbd = (struct coh_super_block *) bh1->b_data; 140 141 *max_links = COH_LINK_MAX; 142 sbi->s_fic_size = COH_NICINOD; 143 sbi->s_flc_size = COH_NICFREE; 144 sbi->s_sbd1 = (char *)sbd; 145 sbi->s_sbd2 = (char *)sbd; 146 sbi->s_sb_fic_count = &sbd->s_ninode; 147 sbi->s_sb_fic_inodes = &sbd->s_inode[0]; 148 sbi->s_sb_total_free_inodes = &sbd->s_tinode; 149 sbi->s_bcache_count = &sbd->s_nfree; 150 sbi->s_bcache = &sbd->s_free[0]; 151 sbi->s_free_blocks = &sbd->s_tfree; 152 sbi->s_sb_time = &sbd->s_time; 153 sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); 154 sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); 155 } 156 157 static void detected_v7(struct sysv_sb_info *sbi, unsigned *max_links) 158 { 159 struct buffer_head *bh2 = sbi->s_bh2; 160 struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data; 161 162 *max_links = V7_LINK_MAX; 163 sbi->s_fic_size = V7_NICINOD; 164 sbi->s_flc_size = V7_NICFREE; 165 sbi->s_sbd1 = (char *)sbd; 166 sbi->s_sbd2 = (char *)sbd; 167 sbi->s_sb_fic_count = &sbd->s_ninode; 168 sbi->s_sb_fic_inodes = &sbd->s_inode[0]; 169 sbi->s_sb_total_free_inodes = &sbd->s_tinode; 170 sbi->s_bcache_count = &sbd->s_nfree; 171 sbi->s_bcache = &sbd->s_free[0]; 172 sbi->s_free_blocks = &sbd->s_tfree; 173 sbi->s_sb_time = &sbd->s_time; 174 sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); 175 sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); 176 } 177 178 static int detect_xenix(struct sysv_sb_info *sbi, struct buffer_head *bh) 179 { 180 struct xenix_super_block *sbd = (struct xenix_super_block *)bh->b_data; 181 if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0x2b5544)) 182 sbi->s_bytesex = BYTESEX_LE; 183 else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0x2b5544)) 184 sbi->s_bytesex = BYTESEX_BE; 185 else 186 return 0; 187 switch (fs32_to_cpu(sbi, sbd->s_type)) { 188 case 1: 189 sbi->s_type = FSTYPE_XENIX; 190 return 1; 191 case 2: 192 sbi->s_type = FSTYPE_XENIX; 193 return 2; 194 default: 195 return 0; 196 } 197 } 198 199 static int detect_sysv(struct sysv_sb_info *sbi, struct buffer_head *bh) 200 { 201 struct super_block *sb = sbi->s_sb; 202 /* All relevant fields are at the same offsets in R2 and R4 */ 203 struct sysv4_super_block * sbd; 204 u32 type; 205 206 sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2); 207 if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0xfd187e20)) 208 sbi->s_bytesex = BYTESEX_LE; 209 else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0xfd187e20)) 210 sbi->s_bytesex = BYTESEX_BE; 211 else 212 return 0; 213 214 type = fs32_to_cpu(sbi, sbd->s_type); 215 216 if (fs16_to_cpu(sbi, sbd->s_nfree) == 0xffff) { 217 sbi->s_type = FSTYPE_AFS; 218 sbi->s_forced_ro = 1; 219 if (!sb_rdonly(sb)) { 220 printk("SysV FS: SCO EAFS on %s detected, " 221 "forcing read-only mode.\n", 222 sb->s_id); 223 } 224 return type; 225 } 226 227 if (fs32_to_cpu(sbi, sbd->s_time) < JAN_1_1980) { 228 /* this is likely to happen on SystemV2 FS */ 229 if (type > 3 || type < 1) 230 return 0; 231 sbi->s_type = FSTYPE_SYSV2; 232 return type; 233 } 234 if ((type > 3 || type < 1) && (type > 0x30 || type < 0x10)) 235 return 0; 236 237 /* On Interactive Unix (ISC) Version 4.0/3.x s_type field = 0x10, 238 0x20 or 0x30 indicates that symbolic links and the 14-character 239 filename limit is gone. Due to lack of information about this 240 feature read-only mode seems to be a reasonable approach... -KGB */ 241 242 if (type >= 0x10) { 243 printk("SysV FS: can't handle long file names on %s, " 244 "forcing read-only mode.\n", sb->s_id); 245 sbi->s_forced_ro = 1; 246 } 247 248 sbi->s_type = FSTYPE_SYSV4; 249 return type >= 0x10 ? type >> 4 : type; 250 } 251 252 static int detect_coherent(struct sysv_sb_info *sbi, struct buffer_head *bh) 253 { 254 struct coh_super_block * sbd; 255 256 sbd = (struct coh_super_block *) (bh->b_data + BLOCK_SIZE/2); 257 if ((memcmp(sbd->s_fname,"noname",6) && memcmp(sbd->s_fname,"xxxxx ",6)) 258 || (memcmp(sbd->s_fpack,"nopack",6) && memcmp(sbd->s_fpack,"xxxxx\n",6))) 259 return 0; 260 sbi->s_bytesex = BYTESEX_PDP; 261 sbi->s_type = FSTYPE_COH; 262 return 1; 263 } 264 265 static int detect_sysv_odd(struct sysv_sb_info *sbi, struct buffer_head *bh) 266 { 267 int size = detect_sysv(sbi, bh); 268 269 return size>2 ? 0 : size; 270 } 271 272 static struct { 273 int block; 274 int (*test)(struct sysv_sb_info *, struct buffer_head *); 275 } flavours[] = { 276 {1, detect_xenix}, 277 {0, detect_sysv}, 278 {0, detect_coherent}, 279 {9, detect_sysv_odd}, 280 {15,detect_sysv_odd}, 281 {18,detect_sysv}, 282 }; 283 284 static char *flavour_names[] = { 285 [FSTYPE_XENIX] = "Xenix", 286 [FSTYPE_SYSV4] = "SystemV", 287 [FSTYPE_SYSV2] = "SystemV Release 2", 288 [FSTYPE_COH] = "Coherent", 289 [FSTYPE_V7] = "V7", 290 [FSTYPE_AFS] = "AFS", 291 }; 292 293 static void (*flavour_setup[])(struct sysv_sb_info *, unsigned *) = { 294 [FSTYPE_XENIX] = detected_xenix, 295 [FSTYPE_SYSV4] = detected_sysv4, 296 [FSTYPE_SYSV2] = detected_sysv2, 297 [FSTYPE_COH] = detected_coherent, 298 [FSTYPE_V7] = detected_v7, 299 [FSTYPE_AFS] = detected_sysv4, 300 }; 301 302 static int complete_read_super(struct super_block *sb, int silent, int size) 303 { 304 struct sysv_sb_info *sbi = SYSV_SB(sb); 305 struct inode *root_inode; 306 char *found = flavour_names[sbi->s_type]; 307 u_char n_bits = size+8; 308 int bsize = 1 << n_bits; 309 int bsize_4 = bsize >> 2; 310 311 sbi->s_firstinodezone = 2; 312 313 flavour_setup[sbi->s_type](sbi, &sb->s_max_links); 314 315 sbi->s_truncate = 1; 316 sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone; 317 sbi->s_inodes_per_block = bsize >> 6; 318 sbi->s_inodes_per_block_1 = (bsize >> 6)-1; 319 sbi->s_inodes_per_block_bits = n_bits-6; 320 sbi->s_ind_per_block = bsize_4; 321 sbi->s_ind_per_block_2 = bsize_4*bsize_4; 322 sbi->s_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4)); 323 sbi->s_ind_per_block_bits = n_bits-2; 324 325 sbi->s_ninodes = (sbi->s_firstdatazone - sbi->s_firstinodezone) 326 << sbi->s_inodes_per_block_bits; 327 328 if (!silent) 329 printk("VFS: Found a %s FS (block size = %ld) on device %s\n", 330 found, sb->s_blocksize, sb->s_id); 331 332 sb->s_magic = SYSV_MAGIC_BASE + sbi->s_type; 333 /* set up enough so that it can read an inode */ 334 sb->s_op = &sysv_sops; 335 if (sbi->s_forced_ro) 336 sb->s_flags |= SB_RDONLY; 337 if (sbi->s_truncate) 338 sb->s_d_op = &sysv_dentry_operations; 339 root_inode = sysv_iget(sb, SYSV_ROOT_INO); 340 if (IS_ERR(root_inode)) { 341 printk("SysV FS: get root inode failed\n"); 342 return 0; 343 } 344 sb->s_root = d_make_root(root_inode); 345 if (!sb->s_root) { 346 printk("SysV FS: get root dentry failed\n"); 347 return 0; 348 } 349 return 1; 350 } 351 352 static int sysv_fill_super(struct super_block *sb, void *data, int silent) 353 { 354 struct buffer_head *bh1, *bh = NULL; 355 struct sysv_sb_info *sbi; 356 unsigned long blocknr; 357 int size = 0, i; 358 359 BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block)); 360 BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block)); 361 BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block)); 362 BUILD_BUG_ON(500 != sizeof (struct coh_super_block)); 363 BUILD_BUG_ON(64 != sizeof (struct sysv_inode)); 364 365 sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); 366 if (!sbi) 367 return -ENOMEM; 368 369 sbi->s_sb = sb; 370 sbi->s_block_base = 0; 371 mutex_init(&sbi->s_lock); 372 sb->s_fs_info = sbi; 373 374 sb_set_blocksize(sb, BLOCK_SIZE); 375 376 for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) { 377 brelse(bh); 378 bh = sb_bread(sb, flavours[i].block); 379 if (!bh) 380 continue; 381 size = flavours[i].test(SYSV_SB(sb), bh); 382 } 383 384 if (!size) 385 goto Eunknown; 386 387 switch (size) { 388 case 1: 389 blocknr = bh->b_blocknr << 1; 390 brelse(bh); 391 sb_set_blocksize(sb, 512); 392 bh1 = sb_bread(sb, blocknr); 393 bh = sb_bread(sb, blocknr + 1); 394 break; 395 case 2: 396 bh1 = bh; 397 break; 398 case 3: 399 blocknr = bh->b_blocknr >> 1; 400 brelse(bh); 401 sb_set_blocksize(sb, 2048); 402 bh1 = bh = sb_bread(sb, blocknr); 403 break; 404 default: 405 goto Ebadsize; 406 } 407 408 if (bh && bh1) { 409 sbi->s_bh1 = bh1; 410 sbi->s_bh2 = bh; 411 if (complete_read_super(sb, silent, size)) 412 return 0; 413 } 414 415 brelse(bh1); 416 brelse(bh); 417 sb_set_blocksize(sb, BLOCK_SIZE); 418 printk("oldfs: cannot read superblock\n"); 419 failed: 420 kfree(sbi); 421 return -EINVAL; 422 423 Eunknown: 424 brelse(bh); 425 if (!silent) 426 printk("VFS: unable to find oldfs superblock on device %s\n", 427 sb->s_id); 428 goto failed; 429 Ebadsize: 430 brelse(bh); 431 if (!silent) 432 printk("VFS: oldfs: unsupported block size (%dKb)\n", 433 1<<(size-2)); 434 goto failed; 435 } 436 437 static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh) 438 { 439 struct v7_super_block *v7sb; 440 struct sysv_inode *v7i; 441 struct buffer_head *bh2; 442 struct sysv_sb_info *sbi; 443 444 sbi = sb->s_fs_info; 445 446 /* plausibility check on superblock */ 447 v7sb = (struct v7_super_block *) bh->b_data; 448 if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE || 449 fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD || 450 fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE) 451 return 0; 452 453 /* plausibility check on root inode: it is a directory, 454 with a nonzero size that is a multiple of 16 */ 455 bh2 = sb_bread(sb, 2); 456 if (bh2 == NULL) 457 return 0; 458 459 v7i = (struct sysv_inode *)(bh2->b_data + 64); 460 if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR || 461 (fs32_to_cpu(sbi, v7i->i_size) == 0) || 462 (fs32_to_cpu(sbi, v7i->i_size) & 017) || 463 (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES * 464 sizeof(struct sysv_dir_entry))) { 465 brelse(bh2); 466 return 0; 467 } 468 469 brelse(bh2); 470 return 1; 471 } 472 473 static int v7_fill_super(struct super_block *sb, void *data, int silent) 474 { 475 struct sysv_sb_info *sbi; 476 struct buffer_head *bh; 477 478 if (440 != sizeof (struct v7_super_block)) 479 panic("V7 FS: bad super-block size"); 480 if (64 != sizeof (struct sysv_inode)) 481 panic("sysv fs: bad i-node size"); 482 483 sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); 484 if (!sbi) 485 return -ENOMEM; 486 487 sbi->s_sb = sb; 488 sbi->s_block_base = 0; 489 sbi->s_type = FSTYPE_V7; 490 mutex_init(&sbi->s_lock); 491 sb->s_fs_info = sbi; 492 493 sb_set_blocksize(sb, 512); 494 495 if ((bh = sb_bread(sb, 1)) == NULL) { 496 if (!silent) 497 printk("VFS: unable to read V7 FS superblock on " 498 "device %s.\n", sb->s_id); 499 goto failed; 500 } 501 502 /* Try PDP-11 UNIX */ 503 sbi->s_bytesex = BYTESEX_PDP; 504 if (v7_sanity_check(sb, bh)) 505 goto detected; 506 507 /* Try PC/IX, v7/x86 */ 508 sbi->s_bytesex = BYTESEX_LE; 509 if (v7_sanity_check(sb, bh)) 510 goto detected; 511 512 goto failed; 513 514 detected: 515 sbi->s_bh1 = bh; 516 sbi->s_bh2 = bh; 517 if (complete_read_super(sb, silent, 1)) 518 return 0; 519 520 failed: 521 printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n", 522 sb->s_id); 523 brelse(bh); 524 kfree(sbi); 525 return -EINVAL; 526 } 527 528 /* Every kernel module contains stuff like this. */ 529 530 static struct dentry *sysv_mount(struct file_system_type *fs_type, 531 int flags, const char *dev_name, void *data) 532 { 533 return mount_bdev(fs_type, flags, dev_name, data, sysv_fill_super); 534 } 535 536 static struct dentry *v7_mount(struct file_system_type *fs_type, 537 int flags, const char *dev_name, void *data) 538 { 539 return mount_bdev(fs_type, flags, dev_name, data, v7_fill_super); 540 } 541 542 static struct file_system_type sysv_fs_type = { 543 .owner = THIS_MODULE, 544 .name = "sysv", 545 .mount = sysv_mount, 546 .kill_sb = kill_block_super, 547 .fs_flags = FS_REQUIRES_DEV, 548 }; 549 MODULE_ALIAS_FS("sysv"); 550 551 static struct file_system_type v7_fs_type = { 552 .owner = THIS_MODULE, 553 .name = "v7", 554 .mount = v7_mount, 555 .kill_sb = kill_block_super, 556 .fs_flags = FS_REQUIRES_DEV, 557 }; 558 MODULE_ALIAS_FS("v7"); 559 MODULE_ALIAS("v7"); 560 561 static int __init init_sysv_fs(void) 562 { 563 int error; 564 565 error = sysv_init_icache(); 566 if (error) 567 goto out; 568 error = register_filesystem(&sysv_fs_type); 569 if (error) 570 goto destroy_icache; 571 error = register_filesystem(&v7_fs_type); 572 if (error) 573 goto unregister; 574 return 0; 575 576 unregister: 577 unregister_filesystem(&sysv_fs_type); 578 destroy_icache: 579 sysv_destroy_icache(); 580 out: 581 return error; 582 } 583 584 static void __exit exit_sysv_fs(void) 585 { 586 unregister_filesystem(&sysv_fs_type); 587 unregister_filesystem(&v7_fs_type); 588 sysv_destroy_icache(); 589 } 590 591 module_init(init_sysv_fs) 592 module_exit(exit_sysv_fs) 593 MODULE_LICENSE("GPL"); 594