1 /* 2 * Optimized MPEG FS - inode and super operations. 3 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com> 4 * Released under GPL v2. 5 */ 6 #include <linux/module.h> 7 #include <linux/sched.h> 8 #include <linux/slab.h> 9 #include <linux/fs.h> 10 #include <linux/vfs.h> 11 #include <linux/parser.h> 12 #include <linux/buffer_head.h> 13 #include <linux/vmalloc.h> 14 #include <linux/writeback.h> 15 #include <linux/crc-itu-t.h> 16 #include "omfs.h" 17 18 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>"); 19 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux"); 20 MODULE_LICENSE("GPL"); 21 22 struct inode *omfs_new_inode(struct inode *dir, int mode) 23 { 24 struct inode *inode; 25 u64 new_block; 26 int err; 27 int len; 28 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb); 29 30 inode = new_inode(dir->i_sb); 31 if (!inode) 32 return ERR_PTR(-ENOMEM); 33 34 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors, 35 &new_block, &len); 36 if (err) 37 goto fail; 38 39 inode->i_ino = new_block; 40 inode_init_owner(inode, NULL, mode); 41 inode->i_mapping->a_ops = &omfs_aops; 42 43 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 44 switch (mode & S_IFMT) { 45 case S_IFDIR: 46 inode->i_op = &omfs_dir_inops; 47 inode->i_fop = &omfs_dir_operations; 48 inode->i_size = sbi->s_sys_blocksize; 49 inc_nlink(inode); 50 break; 51 case S_IFREG: 52 inode->i_op = &omfs_file_inops; 53 inode->i_fop = &omfs_file_operations; 54 inode->i_size = 0; 55 break; 56 } 57 58 insert_inode_hash(inode); 59 mark_inode_dirty(inode); 60 return inode; 61 fail: 62 make_bad_inode(inode); 63 iput(inode); 64 return ERR_PTR(err); 65 } 66 67 /* 68 * Update the header checksums for a dirty inode based on its contents. 69 * Caller is expected to hold the buffer head underlying oi and mark it 70 * dirty. 71 */ 72 static void omfs_update_checksums(struct omfs_inode *oi) 73 { 74 int xor, i, ofs = 0, count; 75 u16 crc = 0; 76 unsigned char *ptr = (unsigned char *) oi; 77 78 count = be32_to_cpu(oi->i_head.h_body_size); 79 ofs = sizeof(struct omfs_header); 80 81 crc = crc_itu_t(crc, ptr + ofs, count); 82 oi->i_head.h_crc = cpu_to_be16(crc); 83 84 xor = ptr[0]; 85 for (i = 1; i < OMFS_XOR_COUNT; i++) 86 xor ^= ptr[i]; 87 88 oi->i_head.h_check_xor = xor; 89 } 90 91 static int __omfs_write_inode(struct inode *inode, int wait) 92 { 93 struct omfs_inode *oi; 94 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); 95 struct buffer_head *bh, *bh2; 96 unsigned int block; 97 u64 ctime; 98 int i; 99 int ret = -EIO; 100 int sync_failed = 0; 101 102 /* get current inode since we may have written sibling ptrs etc. */ 103 block = clus_to_blk(sbi, inode->i_ino); 104 bh = sb_bread(inode->i_sb, block); 105 if (!bh) 106 goto out; 107 108 oi = (struct omfs_inode *) bh->b_data; 109 110 oi->i_head.h_self = cpu_to_be64(inode->i_ino); 111 if (S_ISDIR(inode->i_mode)) 112 oi->i_type = OMFS_DIR; 113 else if (S_ISREG(inode->i_mode)) 114 oi->i_type = OMFS_FILE; 115 else { 116 printk(KERN_WARNING "omfs: unknown file type: %d\n", 117 inode->i_mode); 118 goto out_brelse; 119 } 120 121 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize - 122 sizeof(struct omfs_header)); 123 oi->i_head.h_version = 1; 124 oi->i_head.h_type = OMFS_INODE_NORMAL; 125 oi->i_head.h_magic = OMFS_IMAGIC; 126 oi->i_size = cpu_to_be64(inode->i_size); 127 128 ctime = inode->i_ctime.tv_sec * 1000LL + 129 ((inode->i_ctime.tv_nsec + 999)/1000); 130 oi->i_ctime = cpu_to_be64(ctime); 131 132 omfs_update_checksums(oi); 133 134 mark_buffer_dirty(bh); 135 if (wait) { 136 sync_dirty_buffer(bh); 137 if (buffer_req(bh) && !buffer_uptodate(bh)) 138 sync_failed = 1; 139 } 140 141 /* if mirroring writes, copy to next fsblock */ 142 for (i = 1; i < sbi->s_mirrors; i++) { 143 bh2 = sb_bread(inode->i_sb, block + i * 144 (sbi->s_blocksize / sbi->s_sys_blocksize)); 145 if (!bh2) 146 goto out_brelse; 147 148 memcpy(bh2->b_data, bh->b_data, bh->b_size); 149 mark_buffer_dirty(bh2); 150 if (wait) { 151 sync_dirty_buffer(bh2); 152 if (buffer_req(bh2) && !buffer_uptodate(bh2)) 153 sync_failed = 1; 154 } 155 brelse(bh2); 156 } 157 ret = (sync_failed) ? -EIO : 0; 158 out_brelse: 159 brelse(bh); 160 out: 161 return ret; 162 } 163 164 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc) 165 { 166 return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); 167 } 168 169 int omfs_sync_inode(struct inode *inode) 170 { 171 return __omfs_write_inode(inode, 1); 172 } 173 174 /* 175 * called when an entry is deleted, need to clear the bits in the 176 * bitmaps. 177 */ 178 static void omfs_evict_inode(struct inode *inode) 179 { 180 truncate_inode_pages(&inode->i_data, 0); 181 end_writeback(inode); 182 183 if (inode->i_nlink) 184 return; 185 186 if (S_ISREG(inode->i_mode)) { 187 inode->i_size = 0; 188 omfs_shrink_inode(inode); 189 } 190 191 omfs_clear_range(inode->i_sb, inode->i_ino, 2); 192 } 193 194 struct inode *omfs_iget(struct super_block *sb, ino_t ino) 195 { 196 struct omfs_sb_info *sbi = OMFS_SB(sb); 197 struct omfs_inode *oi; 198 struct buffer_head *bh; 199 unsigned int block; 200 u64 ctime; 201 unsigned long nsecs; 202 struct inode *inode; 203 204 inode = iget_locked(sb, ino); 205 if (!inode) 206 return ERR_PTR(-ENOMEM); 207 if (!(inode->i_state & I_NEW)) 208 return inode; 209 210 block = clus_to_blk(sbi, ino); 211 bh = sb_bread(inode->i_sb, block); 212 if (!bh) 213 goto iget_failed; 214 215 oi = (struct omfs_inode *)bh->b_data; 216 217 /* check self */ 218 if (ino != be64_to_cpu(oi->i_head.h_self)) 219 goto fail_bh; 220 221 inode->i_uid = sbi->s_uid; 222 inode->i_gid = sbi->s_gid; 223 224 ctime = be64_to_cpu(oi->i_ctime); 225 nsecs = do_div(ctime, 1000) * 1000L; 226 227 inode->i_atime.tv_sec = ctime; 228 inode->i_mtime.tv_sec = ctime; 229 inode->i_ctime.tv_sec = ctime; 230 inode->i_atime.tv_nsec = nsecs; 231 inode->i_mtime.tv_nsec = nsecs; 232 inode->i_ctime.tv_nsec = nsecs; 233 234 inode->i_mapping->a_ops = &omfs_aops; 235 236 switch (oi->i_type) { 237 case OMFS_DIR: 238 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask); 239 inode->i_op = &omfs_dir_inops; 240 inode->i_fop = &omfs_dir_operations; 241 inode->i_size = sbi->s_sys_blocksize; 242 inc_nlink(inode); 243 break; 244 case OMFS_FILE: 245 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask); 246 inode->i_fop = &omfs_file_operations; 247 inode->i_size = be64_to_cpu(oi->i_size); 248 break; 249 } 250 brelse(bh); 251 unlock_new_inode(inode); 252 return inode; 253 fail_bh: 254 brelse(bh); 255 iget_failed: 256 iget_failed(inode); 257 return ERR_PTR(-EIO); 258 } 259 260 static void omfs_put_super(struct super_block *sb) 261 { 262 struct omfs_sb_info *sbi = OMFS_SB(sb); 263 kfree(sbi->s_imap); 264 kfree(sbi); 265 sb->s_fs_info = NULL; 266 } 267 268 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf) 269 { 270 struct super_block *s = dentry->d_sb; 271 struct omfs_sb_info *sbi = OMFS_SB(s); 272 u64 id = huge_encode_dev(s->s_bdev->bd_dev); 273 274 buf->f_type = OMFS_MAGIC; 275 buf->f_bsize = sbi->s_blocksize; 276 buf->f_blocks = sbi->s_num_blocks; 277 buf->f_files = sbi->s_num_blocks; 278 buf->f_namelen = OMFS_NAMELEN; 279 buf->f_fsid.val[0] = (u32)id; 280 buf->f_fsid.val[1] = (u32)(id >> 32); 281 282 buf->f_bfree = buf->f_bavail = buf->f_ffree = 283 omfs_count_free(s); 284 285 return 0; 286 } 287 288 static const struct super_operations omfs_sops = { 289 .write_inode = omfs_write_inode, 290 .evict_inode = omfs_evict_inode, 291 .put_super = omfs_put_super, 292 .statfs = omfs_statfs, 293 .show_options = generic_show_options, 294 }; 295 296 /* 297 * For Rio Karma, there is an on-disk free bitmap whose location is 298 * stored in the root block. For ReplayTV, there is no such free bitmap 299 * so we have to walk the tree. Both inodes and file data are allocated 300 * from the same map. This array can be big (300k) so we allocate 301 * in units of the blocksize. 302 */ 303 static int omfs_get_imap(struct super_block *sb) 304 { 305 int bitmap_size; 306 int array_size; 307 int count; 308 struct omfs_sb_info *sbi = OMFS_SB(sb); 309 struct buffer_head *bh; 310 unsigned long **ptr; 311 sector_t block; 312 313 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8); 314 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize); 315 316 if (sbi->s_bitmap_ino == ~0ULL) 317 goto out; 318 319 sbi->s_imap_size = array_size; 320 sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL); 321 if (!sbi->s_imap) 322 goto nomem; 323 324 block = clus_to_blk(sbi, sbi->s_bitmap_ino); 325 ptr = sbi->s_imap; 326 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) { 327 bh = sb_bread(sb, block++); 328 if (!bh) 329 goto nomem_free; 330 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL); 331 if (!*ptr) { 332 brelse(bh); 333 goto nomem_free; 334 } 335 memcpy(*ptr, bh->b_data, sb->s_blocksize); 336 if (count < sb->s_blocksize) 337 memset((void *)*ptr + count, 0xff, 338 sb->s_blocksize - count); 339 brelse(bh); 340 ptr++; 341 } 342 out: 343 return 0; 344 345 nomem_free: 346 for (count = 0; count < array_size; count++) 347 kfree(sbi->s_imap[count]); 348 349 kfree(sbi->s_imap); 350 nomem: 351 sbi->s_imap = NULL; 352 sbi->s_imap_size = 0; 353 return -ENOMEM; 354 } 355 356 enum { 357 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask 358 }; 359 360 static const match_table_t tokens = { 361 {Opt_uid, "uid=%u"}, 362 {Opt_gid, "gid=%u"}, 363 {Opt_umask, "umask=%o"}, 364 {Opt_dmask, "dmask=%o"}, 365 {Opt_fmask, "fmask=%o"}, 366 }; 367 368 static int parse_options(char *options, struct omfs_sb_info *sbi) 369 { 370 char *p; 371 substring_t args[MAX_OPT_ARGS]; 372 int option; 373 374 if (!options) 375 return 1; 376 377 while ((p = strsep(&options, ",")) != NULL) { 378 int token; 379 if (!*p) 380 continue; 381 382 token = match_token(p, tokens, args); 383 switch (token) { 384 case Opt_uid: 385 if (match_int(&args[0], &option)) 386 return 0; 387 sbi->s_uid = option; 388 break; 389 case Opt_gid: 390 if (match_int(&args[0], &option)) 391 return 0; 392 sbi->s_gid = option; 393 break; 394 case Opt_umask: 395 if (match_octal(&args[0], &option)) 396 return 0; 397 sbi->s_fmask = sbi->s_dmask = option; 398 break; 399 case Opt_dmask: 400 if (match_octal(&args[0], &option)) 401 return 0; 402 sbi->s_dmask = option; 403 break; 404 case Opt_fmask: 405 if (match_octal(&args[0], &option)) 406 return 0; 407 sbi->s_fmask = option; 408 break; 409 default: 410 return 0; 411 } 412 } 413 return 1; 414 } 415 416 static int omfs_fill_super(struct super_block *sb, void *data, int silent) 417 { 418 struct buffer_head *bh, *bh2; 419 struct omfs_super_block *omfs_sb; 420 struct omfs_root_block *omfs_rb; 421 struct omfs_sb_info *sbi; 422 struct inode *root; 423 sector_t start; 424 int ret = -EINVAL; 425 426 save_mount_options(sb, (char *) data); 427 428 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL); 429 if (!sbi) 430 return -ENOMEM; 431 432 sb->s_fs_info = sbi; 433 434 sbi->s_uid = current_uid(); 435 sbi->s_gid = current_gid(); 436 sbi->s_dmask = sbi->s_fmask = current_umask(); 437 438 if (!parse_options((char *) data, sbi)) 439 goto end; 440 441 sb->s_maxbytes = 0xffffffff; 442 443 sb_set_blocksize(sb, 0x200); 444 445 bh = sb_bread(sb, 0); 446 if (!bh) 447 goto end; 448 449 omfs_sb = (struct omfs_super_block *)bh->b_data; 450 451 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) { 452 if (!silent) 453 printk(KERN_ERR "omfs: Invalid superblock (%x)\n", 454 omfs_sb->s_magic); 455 goto out_brelse_bh; 456 } 457 sb->s_magic = OMFS_MAGIC; 458 459 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks); 460 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize); 461 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors); 462 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block); 463 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize); 464 mutex_init(&sbi->s_bitmap_lock); 465 466 if (sbi->s_sys_blocksize > PAGE_SIZE) { 467 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n", 468 sbi->s_sys_blocksize); 469 goto out_brelse_bh; 470 } 471 472 if (sbi->s_blocksize < sbi->s_sys_blocksize || 473 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) { 474 printk(KERN_ERR "omfs: block size (%d) is out of range\n", 475 sbi->s_blocksize); 476 goto out_brelse_bh; 477 } 478 479 /* 480 * Use sys_blocksize as the fs block since it is smaller than a 481 * page while the fs blocksize can be larger. 482 */ 483 sb_set_blocksize(sb, sbi->s_sys_blocksize); 484 485 /* 486 * ...and the difference goes into a shift. sys_blocksize is always 487 * a power of two factor of blocksize. 488 */ 489 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) - 490 get_bitmask_order(sbi->s_sys_blocksize); 491 492 start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block)); 493 bh2 = sb_bread(sb, start); 494 if (!bh2) 495 goto out_brelse_bh; 496 497 omfs_rb = (struct omfs_root_block *)bh2->b_data; 498 499 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap); 500 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize); 501 502 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) { 503 printk(KERN_ERR "omfs: block count discrepancy between " 504 "super and root blocks (%llx, %llx)\n", 505 (unsigned long long)sbi->s_num_blocks, 506 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks)); 507 goto out_brelse_bh2; 508 } 509 510 ret = omfs_get_imap(sb); 511 if (ret) 512 goto out_brelse_bh2; 513 514 sb->s_op = &omfs_sops; 515 516 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir)); 517 if (IS_ERR(root)) { 518 ret = PTR_ERR(root); 519 goto out_brelse_bh2; 520 } 521 522 sb->s_root = d_alloc_root(root); 523 if (!sb->s_root) { 524 iput(root); 525 goto out_brelse_bh2; 526 } 527 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name); 528 529 ret = 0; 530 out_brelse_bh2: 531 brelse(bh2); 532 out_brelse_bh: 533 brelse(bh); 534 end: 535 return ret; 536 } 537 538 static int omfs_get_sb(struct file_system_type *fs_type, 539 int flags, const char *dev_name, 540 void *data, struct vfsmount *m) 541 { 542 return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m); 543 } 544 545 static struct file_system_type omfs_fs_type = { 546 .owner = THIS_MODULE, 547 .name = "omfs", 548 .get_sb = omfs_get_sb, 549 .kill_sb = kill_block_super, 550 .fs_flags = FS_REQUIRES_DEV, 551 }; 552 553 static int __init init_omfs_fs(void) 554 { 555 return register_filesystem(&omfs_fs_type); 556 } 557 558 static void __exit exit_omfs_fs(void) 559 { 560 unregister_filesystem(&omfs_fs_type); 561 } 562 563 module_init(init_omfs_fs); 564 module_exit(exit_omfs_fs); 565