1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/mount.h> 15 #include <linux/seq_file.h> 16 #include <linux/init.h> 17 #include <linux/module.h> 18 #include <linux/parser.h> 19 #include <linux/statfs.h> 20 21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 22 MODULE_DESCRIPTION("Filesystem in Userspace"); 23 MODULE_LICENSE("GPL"); 24 25 spinlock_t fuse_lock; 26 static kmem_cache_t *fuse_inode_cachep; 27 28 #define FUSE_SUPER_MAGIC 0x65735546 29 30 struct fuse_mount_data { 31 int fd; 32 unsigned rootmode; 33 unsigned user_id; 34 unsigned group_id; 35 unsigned fd_present : 1; 36 unsigned rootmode_present : 1; 37 unsigned user_id_present : 1; 38 unsigned group_id_present : 1; 39 unsigned flags; 40 unsigned max_read; 41 }; 42 43 static struct inode *fuse_alloc_inode(struct super_block *sb) 44 { 45 struct inode *inode; 46 struct fuse_inode *fi; 47 48 inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL); 49 if (!inode) 50 return NULL; 51 52 fi = get_fuse_inode(inode); 53 fi->i_time = jiffies - 1; 54 fi->nodeid = 0; 55 fi->nlookup = 0; 56 fi->forget_req = fuse_request_alloc(); 57 if (!fi->forget_req) { 58 kmem_cache_free(fuse_inode_cachep, inode); 59 return NULL; 60 } 61 62 return inode; 63 } 64 65 static void fuse_destroy_inode(struct inode *inode) 66 { 67 struct fuse_inode *fi = get_fuse_inode(inode); 68 if (fi->forget_req) 69 fuse_request_free(fi->forget_req); 70 kmem_cache_free(fuse_inode_cachep, inode); 71 } 72 73 static void fuse_read_inode(struct inode *inode) 74 { 75 /* No op */ 76 } 77 78 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 79 unsigned long nodeid, u64 nlookup) 80 { 81 struct fuse_forget_in *inarg = &req->misc.forget_in; 82 inarg->nlookup = nlookup; 83 req->in.h.opcode = FUSE_FORGET; 84 req->in.h.nodeid = nodeid; 85 req->in.numargs = 1; 86 req->in.args[0].size = sizeof(struct fuse_forget_in); 87 req->in.args[0].value = inarg; 88 request_send_noreply(fc, req); 89 } 90 91 static void fuse_clear_inode(struct inode *inode) 92 { 93 if (inode->i_sb->s_flags & MS_ACTIVE) { 94 struct fuse_conn *fc = get_fuse_conn(inode); 95 struct fuse_inode *fi = get_fuse_inode(inode); 96 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); 97 fi->forget_req = NULL; 98 } 99 } 100 101 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) 102 { 103 if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size) 104 invalidate_inode_pages(inode->i_mapping); 105 106 inode->i_ino = attr->ino; 107 inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777); 108 inode->i_nlink = attr->nlink; 109 inode->i_uid = attr->uid; 110 inode->i_gid = attr->gid; 111 i_size_write(inode, attr->size); 112 inode->i_blksize = PAGE_CACHE_SIZE; 113 inode->i_blocks = attr->blocks; 114 inode->i_atime.tv_sec = attr->atime; 115 inode->i_atime.tv_nsec = attr->atimensec; 116 inode->i_mtime.tv_sec = attr->mtime; 117 inode->i_mtime.tv_nsec = attr->mtimensec; 118 inode->i_ctime.tv_sec = attr->ctime; 119 inode->i_ctime.tv_nsec = attr->ctimensec; 120 } 121 122 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 123 { 124 inode->i_mode = attr->mode & S_IFMT; 125 i_size_write(inode, attr->size); 126 if (S_ISREG(inode->i_mode)) { 127 fuse_init_common(inode); 128 fuse_init_file_inode(inode); 129 } else if (S_ISDIR(inode->i_mode)) 130 fuse_init_dir(inode); 131 else if (S_ISLNK(inode->i_mode)) 132 fuse_init_symlink(inode); 133 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 134 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 135 fuse_init_common(inode); 136 init_special_inode(inode, inode->i_mode, 137 new_decode_dev(attr->rdev)); 138 } else { 139 /* Don't let user create weird files */ 140 inode->i_mode = S_IFREG; 141 fuse_init_common(inode); 142 fuse_init_file_inode(inode); 143 } 144 } 145 146 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 147 { 148 unsigned long nodeid = *(unsigned long *) _nodeidp; 149 if (get_node_id(inode) == nodeid) 150 return 1; 151 else 152 return 0; 153 } 154 155 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 156 { 157 unsigned long nodeid = *(unsigned long *) _nodeidp; 158 get_fuse_inode(inode)->nodeid = nodeid; 159 return 0; 160 } 161 162 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, 163 int generation, struct fuse_attr *attr) 164 { 165 struct inode *inode; 166 struct fuse_inode *fi; 167 struct fuse_conn *fc = get_fuse_conn_super(sb); 168 int retried = 0; 169 170 retry: 171 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 172 if (!inode) 173 return NULL; 174 175 if ((inode->i_state & I_NEW)) { 176 inode->i_flags |= S_NOATIME|S_NOCMTIME; 177 inode->i_generation = generation; 178 inode->i_data.backing_dev_info = &fc->bdi; 179 fuse_init_inode(inode, attr); 180 unlock_new_inode(inode); 181 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 182 BUG_ON(retried); 183 /* Inode has changed type, any I/O on the old should fail */ 184 make_bad_inode(inode); 185 iput(inode); 186 retried = 1; 187 goto retry; 188 } 189 190 fi = get_fuse_inode(inode); 191 fi->nlookup ++; 192 fuse_change_attributes(inode, attr); 193 return inode; 194 } 195 196 static void fuse_put_super(struct super_block *sb) 197 { 198 struct fuse_conn *fc = get_fuse_conn_super(sb); 199 200 down_write(&fc->sbput_sem); 201 while (!list_empty(&fc->background)) 202 fuse_release_background(list_entry(fc->background.next, 203 struct fuse_req, bg_entry)); 204 205 spin_lock(&fuse_lock); 206 fc->mounted = 0; 207 fc->user_id = 0; 208 fc->group_id = 0; 209 fc->flags = 0; 210 /* Flush all readers on this fs */ 211 wake_up_all(&fc->waitq); 212 up_write(&fc->sbput_sem); 213 fuse_release_conn(fc); 214 spin_unlock(&fuse_lock); 215 } 216 217 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 218 { 219 stbuf->f_type = FUSE_SUPER_MAGIC; 220 stbuf->f_bsize = attr->bsize; 221 stbuf->f_blocks = attr->blocks; 222 stbuf->f_bfree = attr->bfree; 223 stbuf->f_bavail = attr->bavail; 224 stbuf->f_files = attr->files; 225 stbuf->f_ffree = attr->ffree; 226 stbuf->f_namelen = attr->namelen; 227 /* fsid is left zero */ 228 } 229 230 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf) 231 { 232 struct fuse_conn *fc = get_fuse_conn_super(sb); 233 struct fuse_req *req; 234 struct fuse_statfs_out outarg; 235 int err; 236 237 req = fuse_get_request(fc); 238 if (!req) 239 return -EINTR; 240 241 req->in.numargs = 0; 242 req->in.h.opcode = FUSE_STATFS; 243 req->out.numargs = 1; 244 req->out.args[0].size = sizeof(outarg); 245 req->out.args[0].value = &outarg; 246 request_send(fc, req); 247 err = req->out.h.error; 248 if (!err) 249 convert_fuse_statfs(buf, &outarg.st); 250 fuse_put_request(fc, req); 251 return err; 252 } 253 254 enum { 255 OPT_FD, 256 OPT_ROOTMODE, 257 OPT_USER_ID, 258 OPT_GROUP_ID, 259 OPT_DEFAULT_PERMISSIONS, 260 OPT_ALLOW_OTHER, 261 OPT_MAX_READ, 262 OPT_ERR 263 }; 264 265 static match_table_t tokens = { 266 {OPT_FD, "fd=%u"}, 267 {OPT_ROOTMODE, "rootmode=%o"}, 268 {OPT_USER_ID, "user_id=%u"}, 269 {OPT_GROUP_ID, "group_id=%u"}, 270 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 271 {OPT_ALLOW_OTHER, "allow_other"}, 272 {OPT_MAX_READ, "max_read=%u"}, 273 {OPT_ERR, NULL} 274 }; 275 276 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) 277 { 278 char *p; 279 memset(d, 0, sizeof(struct fuse_mount_data)); 280 d->max_read = ~0; 281 282 while ((p = strsep(&opt, ",")) != NULL) { 283 int token; 284 int value; 285 substring_t args[MAX_OPT_ARGS]; 286 if (!*p) 287 continue; 288 289 token = match_token(p, tokens, args); 290 switch (token) { 291 case OPT_FD: 292 if (match_int(&args[0], &value)) 293 return 0; 294 d->fd = value; 295 d->fd_present = 1; 296 break; 297 298 case OPT_ROOTMODE: 299 if (match_octal(&args[0], &value)) 300 return 0; 301 d->rootmode = value; 302 d->rootmode_present = 1; 303 break; 304 305 case OPT_USER_ID: 306 if (match_int(&args[0], &value)) 307 return 0; 308 d->user_id = value; 309 d->user_id_present = 1; 310 break; 311 312 case OPT_GROUP_ID: 313 if (match_int(&args[0], &value)) 314 return 0; 315 d->group_id = value; 316 d->group_id_present = 1; 317 break; 318 319 case OPT_DEFAULT_PERMISSIONS: 320 d->flags |= FUSE_DEFAULT_PERMISSIONS; 321 break; 322 323 case OPT_ALLOW_OTHER: 324 d->flags |= FUSE_ALLOW_OTHER; 325 break; 326 327 case OPT_MAX_READ: 328 if (match_int(&args[0], &value)) 329 return 0; 330 d->max_read = value; 331 break; 332 333 default: 334 return 0; 335 } 336 } 337 338 if (!d->fd_present || !d->rootmode_present || 339 !d->user_id_present || !d->group_id_present) 340 return 0; 341 342 return 1; 343 } 344 345 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 346 { 347 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 348 349 seq_printf(m, ",user_id=%u", fc->user_id); 350 seq_printf(m, ",group_id=%u", fc->group_id); 351 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 352 seq_puts(m, ",default_permissions"); 353 if (fc->flags & FUSE_ALLOW_OTHER) 354 seq_puts(m, ",allow_other"); 355 if (fc->max_read != ~0) 356 seq_printf(m, ",max_read=%u", fc->max_read); 357 return 0; 358 } 359 360 static void free_conn(struct fuse_conn *fc) 361 { 362 while (!list_empty(&fc->unused_list)) { 363 struct fuse_req *req; 364 req = list_entry(fc->unused_list.next, struct fuse_req, list); 365 list_del(&req->list); 366 fuse_request_free(req); 367 } 368 kfree(fc); 369 } 370 371 /* Must be called with the fuse lock held */ 372 void fuse_release_conn(struct fuse_conn *fc) 373 { 374 fc->count--; 375 if (!fc->count) 376 free_conn(fc); 377 } 378 379 static struct fuse_conn *new_conn(void) 380 { 381 struct fuse_conn *fc; 382 383 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 384 if (fc != NULL) { 385 int i; 386 memset(fc, 0, sizeof(*fc)); 387 init_waitqueue_head(&fc->waitq); 388 INIT_LIST_HEAD(&fc->pending); 389 INIT_LIST_HEAD(&fc->processing); 390 INIT_LIST_HEAD(&fc->unused_list); 391 INIT_LIST_HEAD(&fc->background); 392 sema_init(&fc->outstanding_sem, 0); 393 init_rwsem(&fc->sbput_sem); 394 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) { 395 struct fuse_req *req = fuse_request_alloc(); 396 if (!req) { 397 free_conn(fc); 398 return NULL; 399 } 400 list_add(&req->list, &fc->unused_list); 401 } 402 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 403 fc->bdi.unplug_io_fn = default_unplug_io_fn; 404 fc->reqctr = 0; 405 } 406 return fc; 407 } 408 409 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb) 410 { 411 struct fuse_conn *fc; 412 413 if (file->f_op != &fuse_dev_operations) 414 return ERR_PTR(-EINVAL); 415 fc = new_conn(); 416 if (fc == NULL) 417 return ERR_PTR(-ENOMEM); 418 spin_lock(&fuse_lock); 419 if (file->private_data) { 420 free_conn(fc); 421 fc = ERR_PTR(-EINVAL); 422 } else { 423 file->private_data = fc; 424 *get_fuse_conn_super_p(sb) = fc; 425 fc->mounted = 1; 426 fc->connected = 1; 427 fc->count = 2; 428 } 429 spin_unlock(&fuse_lock); 430 return fc; 431 } 432 433 static struct inode *get_root_inode(struct super_block *sb, unsigned mode) 434 { 435 struct fuse_attr attr; 436 memset(&attr, 0, sizeof(attr)); 437 438 attr.mode = mode; 439 attr.ino = FUSE_ROOT_ID; 440 return fuse_iget(sb, 1, 0, &attr); 441 } 442 443 static struct super_operations fuse_super_operations = { 444 .alloc_inode = fuse_alloc_inode, 445 .destroy_inode = fuse_destroy_inode, 446 .read_inode = fuse_read_inode, 447 .clear_inode = fuse_clear_inode, 448 .put_super = fuse_put_super, 449 .statfs = fuse_statfs, 450 .show_options = fuse_show_options, 451 }; 452 453 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 454 { 455 struct fuse_conn *fc; 456 struct inode *root; 457 struct fuse_mount_data d; 458 struct file *file; 459 int err; 460 461 if (!parse_fuse_opt((char *) data, &d)) 462 return -EINVAL; 463 464 sb->s_blocksize = PAGE_CACHE_SIZE; 465 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 466 sb->s_magic = FUSE_SUPER_MAGIC; 467 sb->s_op = &fuse_super_operations; 468 sb->s_maxbytes = MAX_LFS_FILESIZE; 469 470 file = fget(d.fd); 471 if (!file) 472 return -EINVAL; 473 474 fc = get_conn(file, sb); 475 fput(file); 476 if (IS_ERR(fc)) 477 return PTR_ERR(fc); 478 479 fc->flags = d.flags; 480 fc->user_id = d.user_id; 481 fc->group_id = d.group_id; 482 fc->max_read = d.max_read; 483 if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages) 484 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE; 485 fc->max_write = FUSE_MAX_IN / 2; 486 487 err = -ENOMEM; 488 root = get_root_inode(sb, d.rootmode); 489 if (root == NULL) 490 goto err; 491 492 sb->s_root = d_alloc_root(root); 493 if (!sb->s_root) { 494 iput(root); 495 goto err; 496 } 497 fuse_send_init(fc); 498 return 0; 499 500 err: 501 spin_lock(&fuse_lock); 502 fuse_release_conn(fc); 503 spin_unlock(&fuse_lock); 504 return err; 505 } 506 507 static struct super_block *fuse_get_sb(struct file_system_type *fs_type, 508 int flags, const char *dev_name, 509 void *raw_data) 510 { 511 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super); 512 } 513 514 static struct file_system_type fuse_fs_type = { 515 .owner = THIS_MODULE, 516 .name = "fuse", 517 .get_sb = fuse_get_sb, 518 .kill_sb = kill_anon_super, 519 }; 520 521 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, 522 unsigned long flags) 523 { 524 struct inode * inode = foo; 525 526 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 527 SLAB_CTOR_CONSTRUCTOR) 528 inode_init_once(inode); 529 } 530 531 static int __init fuse_fs_init(void) 532 { 533 int err; 534 535 err = register_filesystem(&fuse_fs_type); 536 if (err) 537 printk("fuse: failed to register filesystem\n"); 538 else { 539 fuse_inode_cachep = kmem_cache_create("fuse_inode", 540 sizeof(struct fuse_inode), 541 0, SLAB_HWCACHE_ALIGN, 542 fuse_inode_init_once, NULL); 543 if (!fuse_inode_cachep) { 544 unregister_filesystem(&fuse_fs_type); 545 err = -ENOMEM; 546 } 547 } 548 549 return err; 550 } 551 552 static void fuse_fs_cleanup(void) 553 { 554 unregister_filesystem(&fuse_fs_type); 555 kmem_cache_destroy(fuse_inode_cachep); 556 } 557 558 static int __init fuse_init(void) 559 { 560 int res; 561 562 printk("fuse init (API version %i.%i)\n", 563 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 564 565 spin_lock_init(&fuse_lock); 566 res = fuse_fs_init(); 567 if (res) 568 goto err; 569 570 res = fuse_dev_init(); 571 if (res) 572 goto err_fs_cleanup; 573 574 return 0; 575 576 err_fs_cleanup: 577 fuse_fs_cleanup(); 578 err: 579 return res; 580 } 581 582 static void __exit fuse_exit(void) 583 { 584 printk(KERN_DEBUG "fuse exit\n"); 585 586 fuse_fs_cleanup(); 587 fuse_dev_cleanup(); 588 } 589 590 module_init(fuse_init); 591 module_exit(fuse_exit); 592