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) 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 sbi->s_link_max = 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) 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 sbi->s_link_max = 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) 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 sbi->s_link_max = 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) 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 sbi->s_link_max = 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) 158 { 159 struct buffer_head *bh2 = sbi->s_bh2; 160 struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data; 161 162 sbi->s_link_max = 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->s_flags & MS_RDONLY)) { 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 *) = { 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); 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 root_inode = sysv_iget(sb, SYSV_ROOT_INO); 336 if (IS_ERR(root_inode)) { 337 printk("SysV FS: get root inode failed\n"); 338 return 0; 339 } 340 sb->s_root = d_alloc_root(root_inode); 341 if (!sb->s_root) { 342 iput(root_inode); 343 printk("SysV FS: get root dentry failed\n"); 344 return 0; 345 } 346 if (sbi->s_forced_ro) 347 sb->s_flags |= MS_RDONLY; 348 if (sbi->s_truncate) 349 sb->s_root->d_op = &sysv_dentry_operations; 350 sb->s_dirt = 1; 351 return 1; 352 } 353 354 static int sysv_fill_super(struct super_block *sb, void *data, int silent) 355 { 356 struct buffer_head *bh1, *bh = NULL; 357 struct sysv_sb_info *sbi; 358 unsigned long blocknr; 359 int size = 0, i; 360 361 BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block)); 362 BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block)); 363 BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block)); 364 BUILD_BUG_ON(500 != sizeof (struct coh_super_block)); 365 BUILD_BUG_ON(64 != sizeof (struct sysv_inode)); 366 367 sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); 368 if (!sbi) 369 return -ENOMEM; 370 371 sbi->s_sb = sb; 372 sbi->s_block_base = 0; 373 sb->s_fs_info = sbi; 374 375 sb_set_blocksize(sb, BLOCK_SIZE); 376 377 for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) { 378 brelse(bh); 379 bh = sb_bread(sb, flavours[i].block); 380 if (!bh) 381 continue; 382 size = flavours[i].test(SYSV_SB(sb), bh); 383 } 384 385 if (!size) 386 goto Eunknown; 387 388 switch (size) { 389 case 1: 390 blocknr = bh->b_blocknr << 1; 391 brelse(bh); 392 sb_set_blocksize(sb, 512); 393 bh1 = sb_bread(sb, blocknr); 394 bh = sb_bread(sb, blocknr + 1); 395 break; 396 case 2: 397 bh1 = bh; 398 break; 399 case 3: 400 blocknr = bh->b_blocknr >> 1; 401 brelse(bh); 402 sb_set_blocksize(sb, 2048); 403 bh1 = bh = sb_bread(sb, blocknr); 404 break; 405 default: 406 goto Ebadsize; 407 } 408 409 if (bh && bh1) { 410 sbi->s_bh1 = bh1; 411 sbi->s_bh2 = bh; 412 if (complete_read_super(sb, silent, size)) 413 return 0; 414 } 415 416 brelse(bh1); 417 brelse(bh); 418 sb_set_blocksize(sb, BLOCK_SIZE); 419 printk("oldfs: cannot read superblock\n"); 420 failed: 421 kfree(sbi); 422 return -EINVAL; 423 424 Eunknown: 425 brelse(bh); 426 if (!silent) 427 printk("VFS: unable to find oldfs superblock on device %s\n", 428 sb->s_id); 429 goto failed; 430 Ebadsize: 431 brelse(bh); 432 if (!silent) 433 printk("VFS: oldfs: unsupported block size (%dKb)\n", 434 1<<(size-2)); 435 goto failed; 436 } 437 438 static int v7_fill_super(struct super_block *sb, void *data, int silent) 439 { 440 struct sysv_sb_info *sbi; 441 struct buffer_head *bh, *bh2 = NULL; 442 struct v7_super_block *v7sb; 443 struct sysv_inode *v7i; 444 445 if (440 != sizeof (struct v7_super_block)) 446 panic("V7 FS: bad super-block size"); 447 if (64 != sizeof (struct sysv_inode)) 448 panic("sysv fs: bad i-node size"); 449 450 sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); 451 if (!sbi) 452 return -ENOMEM; 453 454 sbi->s_sb = sb; 455 sbi->s_block_base = 0; 456 sbi->s_type = FSTYPE_V7; 457 sbi->s_bytesex = BYTESEX_PDP; 458 sb->s_fs_info = sbi; 459 460 sb_set_blocksize(sb, 512); 461 462 if ((bh = sb_bread(sb, 1)) == NULL) { 463 if (!silent) 464 printk("VFS: unable to read V7 FS superblock on " 465 "device %s.\n", sb->s_id); 466 goto failed; 467 } 468 469 /* plausibility check on superblock */ 470 v7sb = (struct v7_super_block *) bh->b_data; 471 if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE || 472 fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD || 473 fs32_to_cpu(sbi, v7sb->s_time) == 0) 474 goto failed; 475 476 /* plausibility check on root inode: it is a directory, 477 with a nonzero size that is a multiple of 16 */ 478 if ((bh2 = sb_bread(sb, 2)) == NULL) 479 goto failed; 480 v7i = (struct sysv_inode *)(bh2->b_data + 64); 481 if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR || 482 (fs32_to_cpu(sbi, v7i->i_size) == 0) || 483 (fs32_to_cpu(sbi, v7i->i_size) & 017) != 0) 484 goto failed; 485 brelse(bh2); 486 bh2 = NULL; 487 488 sbi->s_bh1 = bh; 489 sbi->s_bh2 = bh; 490 if (complete_read_super(sb, silent, 1)) 491 return 0; 492 493 failed: 494 brelse(bh2); 495 brelse(bh); 496 kfree(sbi); 497 return -EINVAL; 498 } 499 500 /* Every kernel module contains stuff like this. */ 501 502 static int sysv_get_sb(struct file_system_type *fs_type, 503 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 504 { 505 return get_sb_bdev(fs_type, flags, dev_name, data, sysv_fill_super, 506 mnt); 507 } 508 509 static int v7_get_sb(struct file_system_type *fs_type, 510 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 511 { 512 return get_sb_bdev(fs_type, flags, dev_name, data, v7_fill_super, mnt); 513 } 514 515 static struct file_system_type sysv_fs_type = { 516 .owner = THIS_MODULE, 517 .name = "sysv", 518 .get_sb = sysv_get_sb, 519 .kill_sb = kill_block_super, 520 .fs_flags = FS_REQUIRES_DEV, 521 }; 522 523 static struct file_system_type v7_fs_type = { 524 .owner = THIS_MODULE, 525 .name = "v7", 526 .get_sb = v7_get_sb, 527 .kill_sb = kill_block_super, 528 .fs_flags = FS_REQUIRES_DEV, 529 }; 530 531 static int __init init_sysv_fs(void) 532 { 533 int error; 534 535 error = sysv_init_icache(); 536 if (error) 537 goto out; 538 error = register_filesystem(&sysv_fs_type); 539 if (error) 540 goto destroy_icache; 541 error = register_filesystem(&v7_fs_type); 542 if (error) 543 goto unregister; 544 return 0; 545 546 unregister: 547 unregister_filesystem(&sysv_fs_type); 548 destroy_icache: 549 sysv_destroy_icache(); 550 out: 551 return error; 552 } 553 554 static void __exit exit_sysv_fs(void) 555 { 556 unregister_filesystem(&sysv_fs_type); 557 unregister_filesystem(&v7_fs_type); 558 sysv_destroy_icache(); 559 } 560 561 module_init(init_sysv_fs) 562 module_exit(exit_sysv_fs) 563 MODULE_LICENSE("GPL"); 564