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 BUG(); 140 } 141 142 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 143 { 144 unsigned long nodeid = *(unsigned long *) _nodeidp; 145 if (get_node_id(inode) == nodeid) 146 return 1; 147 else 148 return 0; 149 } 150 151 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 152 { 153 unsigned long nodeid = *(unsigned long *) _nodeidp; 154 get_fuse_inode(inode)->nodeid = nodeid; 155 return 0; 156 } 157 158 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, 159 int generation, struct fuse_attr *attr) 160 { 161 struct inode *inode; 162 struct fuse_inode *fi; 163 struct fuse_conn *fc = get_fuse_conn_super(sb); 164 int retried = 0; 165 166 retry: 167 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 168 if (!inode) 169 return NULL; 170 171 if ((inode->i_state & I_NEW)) { 172 inode->i_flags |= S_NOATIME|S_NOCMTIME; 173 inode->i_generation = generation; 174 inode->i_data.backing_dev_info = &fc->bdi; 175 fuse_init_inode(inode, attr); 176 unlock_new_inode(inode); 177 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 178 BUG_ON(retried); 179 /* Inode has changed type, any I/O on the old should fail */ 180 make_bad_inode(inode); 181 iput(inode); 182 retried = 1; 183 goto retry; 184 } 185 186 fi = get_fuse_inode(inode); 187 fi->nlookup ++; 188 fuse_change_attributes(inode, attr); 189 return inode; 190 } 191 192 static void fuse_put_super(struct super_block *sb) 193 { 194 struct fuse_conn *fc = get_fuse_conn_super(sb); 195 196 down_write(&fc->sbput_sem); 197 while (!list_empty(&fc->background)) 198 fuse_release_background(list_entry(fc->background.next, 199 struct fuse_req, bg_entry)); 200 201 spin_lock(&fuse_lock); 202 fc->mounted = 0; 203 fc->user_id = 0; 204 fc->group_id = 0; 205 fc->flags = 0; 206 /* Flush all readers on this fs */ 207 wake_up_all(&fc->waitq); 208 up_write(&fc->sbput_sem); 209 fuse_release_conn(fc); 210 spin_unlock(&fuse_lock); 211 } 212 213 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 214 { 215 stbuf->f_type = FUSE_SUPER_MAGIC; 216 stbuf->f_bsize = attr->bsize; 217 stbuf->f_frsize = attr->frsize; 218 stbuf->f_blocks = attr->blocks; 219 stbuf->f_bfree = attr->bfree; 220 stbuf->f_bavail = attr->bavail; 221 stbuf->f_files = attr->files; 222 stbuf->f_ffree = attr->ffree; 223 stbuf->f_namelen = attr->namelen; 224 /* fsid is left zero */ 225 } 226 227 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf) 228 { 229 struct fuse_conn *fc = get_fuse_conn_super(sb); 230 struct fuse_req *req; 231 struct fuse_statfs_out outarg; 232 int err; 233 234 req = fuse_get_request(fc); 235 if (!req) 236 return -EINTR; 237 238 memset(&outarg, 0, sizeof(outarg)); 239 req->in.numargs = 0; 240 req->in.h.opcode = FUSE_STATFS; 241 req->out.numargs = 1; 242 req->out.args[0].size = 243 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 244 req->out.args[0].value = &outarg; 245 request_send(fc, req); 246 err = req->out.h.error; 247 if (!err) 248 convert_fuse_statfs(buf, &outarg.st); 249 fuse_put_request(fc, req); 250 return err; 251 } 252 253 enum { 254 OPT_FD, 255 OPT_ROOTMODE, 256 OPT_USER_ID, 257 OPT_GROUP_ID, 258 OPT_DEFAULT_PERMISSIONS, 259 OPT_ALLOW_OTHER, 260 OPT_MAX_READ, 261 OPT_ERR 262 }; 263 264 static match_table_t tokens = { 265 {OPT_FD, "fd=%u"}, 266 {OPT_ROOTMODE, "rootmode=%o"}, 267 {OPT_USER_ID, "user_id=%u"}, 268 {OPT_GROUP_ID, "group_id=%u"}, 269 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 270 {OPT_ALLOW_OTHER, "allow_other"}, 271 {OPT_MAX_READ, "max_read=%u"}, 272 {OPT_ERR, NULL} 273 }; 274 275 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) 276 { 277 char *p; 278 memset(d, 0, sizeof(struct fuse_mount_data)); 279 d->max_read = ~0; 280 281 while ((p = strsep(&opt, ",")) != NULL) { 282 int token; 283 int value; 284 substring_t args[MAX_OPT_ARGS]; 285 if (!*p) 286 continue; 287 288 token = match_token(p, tokens, args); 289 switch (token) { 290 case OPT_FD: 291 if (match_int(&args[0], &value)) 292 return 0; 293 d->fd = value; 294 d->fd_present = 1; 295 break; 296 297 case OPT_ROOTMODE: 298 if (match_octal(&args[0], &value)) 299 return 0; 300 d->rootmode = value; 301 d->rootmode_present = 1; 302 break; 303 304 case OPT_USER_ID: 305 if (match_int(&args[0], &value)) 306 return 0; 307 d->user_id = value; 308 d->user_id_present = 1; 309 break; 310 311 case OPT_GROUP_ID: 312 if (match_int(&args[0], &value)) 313 return 0; 314 d->group_id = value; 315 d->group_id_present = 1; 316 break; 317 318 case OPT_DEFAULT_PERMISSIONS: 319 d->flags |= FUSE_DEFAULT_PERMISSIONS; 320 break; 321 322 case OPT_ALLOW_OTHER: 323 d->flags |= FUSE_ALLOW_OTHER; 324 break; 325 326 case OPT_MAX_READ: 327 if (match_int(&args[0], &value)) 328 return 0; 329 d->max_read = value; 330 break; 331 332 default: 333 return 0; 334 } 335 } 336 337 if (!d->fd_present || !d->rootmode_present || 338 !d->user_id_present || !d->group_id_present) 339 return 0; 340 341 return 1; 342 } 343 344 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 345 { 346 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 347 348 seq_printf(m, ",user_id=%u", fc->user_id); 349 seq_printf(m, ",group_id=%u", fc->group_id); 350 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 351 seq_puts(m, ",default_permissions"); 352 if (fc->flags & FUSE_ALLOW_OTHER) 353 seq_puts(m, ",allow_other"); 354 if (fc->max_read != ~0) 355 seq_printf(m, ",max_read=%u", fc->max_read); 356 return 0; 357 } 358 359 static void free_conn(struct fuse_conn *fc) 360 { 361 while (!list_empty(&fc->unused_list)) { 362 struct fuse_req *req; 363 req = list_entry(fc->unused_list.next, struct fuse_req, list); 364 list_del(&req->list); 365 fuse_request_free(req); 366 } 367 kfree(fc); 368 } 369 370 /* Must be called with the fuse lock held */ 371 void fuse_release_conn(struct fuse_conn *fc) 372 { 373 fc->count--; 374 if (!fc->count) 375 free_conn(fc); 376 } 377 378 static struct fuse_conn *new_conn(void) 379 { 380 struct fuse_conn *fc; 381 382 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 383 if (fc != NULL) { 384 int i; 385 memset(fc, 0, sizeof(*fc)); 386 init_waitqueue_head(&fc->waitq); 387 INIT_LIST_HEAD(&fc->pending); 388 INIT_LIST_HEAD(&fc->processing); 389 INIT_LIST_HEAD(&fc->unused_list); 390 INIT_LIST_HEAD(&fc->background); 391 sema_init(&fc->outstanding_sem, 0); 392 init_rwsem(&fc->sbput_sem); 393 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) { 394 struct fuse_req *req = fuse_request_alloc(); 395 if (!req) { 396 free_conn(fc); 397 return NULL; 398 } 399 list_add(&req->list, &fc->unused_list); 400 } 401 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 402 fc->bdi.unplug_io_fn = default_unplug_io_fn; 403 fc->reqctr = 0; 404 } 405 return fc; 406 } 407 408 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb) 409 { 410 struct fuse_conn *fc; 411 412 if (file->f_op != &fuse_dev_operations) 413 return ERR_PTR(-EINVAL); 414 fc = new_conn(); 415 if (fc == NULL) 416 return ERR_PTR(-ENOMEM); 417 spin_lock(&fuse_lock); 418 if (file->private_data) { 419 free_conn(fc); 420 fc = ERR_PTR(-EINVAL); 421 } else { 422 file->private_data = fc; 423 *get_fuse_conn_super_p(sb) = fc; 424 fc->mounted = 1; 425 fc->connected = 1; 426 fc->count = 2; 427 } 428 spin_unlock(&fuse_lock); 429 return fc; 430 } 431 432 static struct inode *get_root_inode(struct super_block *sb, unsigned mode) 433 { 434 struct fuse_attr attr; 435 memset(&attr, 0, sizeof(attr)); 436 437 attr.mode = mode; 438 attr.ino = FUSE_ROOT_ID; 439 return fuse_iget(sb, 1, 0, &attr); 440 } 441 442 static struct super_operations fuse_super_operations = { 443 .alloc_inode = fuse_alloc_inode, 444 .destroy_inode = fuse_destroy_inode, 445 .read_inode = fuse_read_inode, 446 .clear_inode = fuse_clear_inode, 447 .put_super = fuse_put_super, 448 .statfs = fuse_statfs, 449 .show_options = fuse_show_options, 450 }; 451 452 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 453 { 454 struct fuse_conn *fc; 455 struct inode *root; 456 struct fuse_mount_data d; 457 struct file *file; 458 int err; 459 460 if (!parse_fuse_opt((char *) data, &d)) 461 return -EINVAL; 462 463 sb->s_blocksize = PAGE_CACHE_SIZE; 464 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 465 sb->s_magic = FUSE_SUPER_MAGIC; 466 sb->s_op = &fuse_super_operations; 467 sb->s_maxbytes = MAX_LFS_FILESIZE; 468 469 file = fget(d.fd); 470 if (!file) 471 return -EINVAL; 472 473 fc = get_conn(file, sb); 474 fput(file); 475 if (IS_ERR(fc)) 476 return PTR_ERR(fc); 477 478 fc->flags = d.flags; 479 fc->user_id = d.user_id; 480 fc->group_id = d.group_id; 481 fc->max_read = d.max_read; 482 if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages) 483 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE; 484 485 err = -ENOMEM; 486 root = get_root_inode(sb, d.rootmode); 487 if (root == NULL) 488 goto err; 489 490 sb->s_root = d_alloc_root(root); 491 if (!sb->s_root) { 492 iput(root); 493 goto err; 494 } 495 fuse_send_init(fc); 496 return 0; 497 498 err: 499 spin_lock(&fuse_lock); 500 fuse_release_conn(fc); 501 spin_unlock(&fuse_lock); 502 return err; 503 } 504 505 static struct super_block *fuse_get_sb(struct file_system_type *fs_type, 506 int flags, const char *dev_name, 507 void *raw_data) 508 { 509 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super); 510 } 511 512 static struct file_system_type fuse_fs_type = { 513 .owner = THIS_MODULE, 514 .name = "fuse", 515 .get_sb = fuse_get_sb, 516 .kill_sb = kill_anon_super, 517 }; 518 519 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, 520 unsigned long flags) 521 { 522 struct inode * inode = foo; 523 524 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 525 SLAB_CTOR_CONSTRUCTOR) 526 inode_init_once(inode); 527 } 528 529 static int __init fuse_fs_init(void) 530 { 531 int err; 532 533 err = register_filesystem(&fuse_fs_type); 534 if (err) 535 printk("fuse: failed to register filesystem\n"); 536 else { 537 fuse_inode_cachep = kmem_cache_create("fuse_inode", 538 sizeof(struct fuse_inode), 539 0, SLAB_HWCACHE_ALIGN, 540 fuse_inode_init_once, NULL); 541 if (!fuse_inode_cachep) { 542 unregister_filesystem(&fuse_fs_type); 543 err = -ENOMEM; 544 } 545 } 546 547 return err; 548 } 549 550 static void fuse_fs_cleanup(void) 551 { 552 unregister_filesystem(&fuse_fs_type); 553 kmem_cache_destroy(fuse_inode_cachep); 554 } 555 556 static int __init fuse_init(void) 557 { 558 int res; 559 560 printk("fuse init (API version %i.%i)\n", 561 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 562 563 spin_lock_init(&fuse_lock); 564 res = fuse_fs_init(); 565 if (res) 566 goto err; 567 568 res = fuse_dev_init(); 569 if (res) 570 goto err_fs_cleanup; 571 572 return 0; 573 574 err_fs_cleanup: 575 fuse_fs_cleanup(); 576 err: 577 return res; 578 } 579 580 static void __exit fuse_exit(void) 581 { 582 printk(KERN_DEBUG "fuse exit\n"); 583 584 fuse_fs_cleanup(); 585 fuse_dev_cleanup(); 586 } 587 588 module_init(fuse_init); 589 module_exit(fuse_exit); 590