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1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 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/seq_file.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/parser.h>
19 #include <linux/statfs.h>
20 #include <linux/random.h>
21 #include <linux/sched.h>
22 #include <linux/exportfs.h>
23
24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
25 MODULE_DESCRIPTION("Filesystem in Userspace");
26 MODULE_LICENSE("GPL");
27
28 static struct kmem_cache *fuse_inode_cachep;
29 struct list_head fuse_conn_list;
30 DEFINE_MUTEX(fuse_mutex);
31
32 static int set_global_limit(const char *val, struct kernel_param *kp);
33
34 unsigned max_user_bgreq;
35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
36 &max_user_bgreq, 0644);
37 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
38 MODULE_PARM_DESC(max_user_bgreq,
39 "Global limit for the maximum number of backgrounded requests an "
40 "unprivileged user can set");
41
42 unsigned max_user_congthresh;
43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
44 &max_user_congthresh, 0644);
45 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
46 MODULE_PARM_DESC(max_user_congthresh,
47 "Global limit for the maximum congestion threshold an "
48 "unprivileged user can set");
49
50 #define FUSE_SUPER_MAGIC 0x65735546
51
52 #define FUSE_DEFAULT_BLKSIZE 512
53
54 /** Maximum number of outstanding background requests */
55 #define FUSE_DEFAULT_MAX_BACKGROUND 12
56
57 /** Congestion starts at 75% of maximum */
58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
59
60 struct fuse_mount_data {
61 int fd;
62 unsigned rootmode;
63 kuid_t user_id;
64 kgid_t group_id;
65 unsigned fd_present:1;
66 unsigned rootmode_present:1;
67 unsigned user_id_present:1;
68 unsigned group_id_present:1;
69 unsigned flags;
70 unsigned max_read;
71 unsigned blksize;
72 };
73
74 struct fuse_forget_link *fuse_alloc_forget(void)
75 {
76 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
77 }
78
79 static struct inode *fuse_alloc_inode(struct super_block *sb)
80 {
81 struct inode *inode;
82 struct fuse_inode *fi;
83
84 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
85 if (!inode)
86 return NULL;
87
88 fi = get_fuse_inode(inode);
89 fi->i_time = 0;
90 fi->nodeid = 0;
91 fi->nlookup = 0;
92 fi->attr_version = 0;
93 fi->writectr = 0;
94 fi->orig_ino = 0;
95 fi->state = 0;
96 INIT_LIST_HEAD(&fi->write_files);
97 INIT_LIST_HEAD(&fi->queued_writes);
98 INIT_LIST_HEAD(&fi->writepages);
99 init_waitqueue_head(&fi->page_waitq);
100 fi->forget = fuse_alloc_forget();
101 if (!fi->forget) {
102 kmem_cache_free(fuse_inode_cachep, inode);
103 return NULL;
104 }
105
106 return inode;
107 }
108
109 static void fuse_i_callback(struct rcu_head *head)
110 {
111 struct inode *inode = container_of(head, struct inode, i_rcu);
112 kmem_cache_free(fuse_inode_cachep, inode);
113 }
114
115 static void fuse_destroy_inode(struct inode *inode)
116 {
117 struct fuse_inode *fi = get_fuse_inode(inode);
118 BUG_ON(!list_empty(&fi->write_files));
119 BUG_ON(!list_empty(&fi->queued_writes));
120 kfree(fi->forget);
121 call_rcu(&inode->i_rcu, fuse_i_callback);
122 }
123
124 static void fuse_evict_inode(struct inode *inode)
125 {
126 truncate_inode_pages_final(&inode->i_data);
127 clear_inode(inode);
128 if (inode->i_sb->s_flags & MS_ACTIVE) {
129 struct fuse_conn *fc = get_fuse_conn(inode);
130 struct fuse_inode *fi = get_fuse_inode(inode);
131 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
132 fi->forget = NULL;
133 }
134 }
135
136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
137 {
138 sync_filesystem(sb);
139 if (*flags & MS_MANDLOCK)
140 return -EINVAL;
141
142 return 0;
143 }
144
145 /*
146 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
147 * so that it will fit.
148 */
149 static ino_t fuse_squash_ino(u64 ino64)
150 {
151 ino_t ino = (ino_t) ino64;
152 if (sizeof(ino_t) < sizeof(u64))
153 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
154 return ino;
155 }
156
157 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
158 u64 attr_valid)
159 {
160 struct fuse_conn *fc = get_fuse_conn(inode);
161 struct fuse_inode *fi = get_fuse_inode(inode);
162
163 fi->attr_version = ++fc->attr_version;
164 fi->i_time = attr_valid;
165
166 inode->i_ino = fuse_squash_ino(attr->ino);
167 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
168 set_nlink(inode, attr->nlink);
169 inode->i_uid = make_kuid(&init_user_ns, attr->uid);
170 inode->i_gid = make_kgid(&init_user_ns, attr->gid);
171 inode->i_blocks = attr->blocks;
172 inode->i_atime.tv_sec = attr->atime;
173 inode->i_atime.tv_nsec = attr->atimensec;
174 /* mtime from server may be stale due to local buffered write */
175 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
176 inode->i_mtime.tv_sec = attr->mtime;
177 inode->i_mtime.tv_nsec = attr->mtimensec;
178 inode->i_ctime.tv_sec = attr->ctime;
179 inode->i_ctime.tv_nsec = attr->ctimensec;
180 }
181
182 if (attr->blksize != 0)
183 inode->i_blkbits = ilog2(attr->blksize);
184 else
185 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
186
187 /*
188 * Don't set the sticky bit in i_mode, unless we want the VFS
189 * to check permissions. This prevents failures due to the
190 * check in may_delete().
191 */
192 fi->orig_i_mode = inode->i_mode;
193 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
194 inode->i_mode &= ~S_ISVTX;
195
196 fi->orig_ino = attr->ino;
197 }
198
199 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
200 u64 attr_valid, u64 attr_version)
201 {
202 struct fuse_conn *fc = get_fuse_conn(inode);
203 struct fuse_inode *fi = get_fuse_inode(inode);
204 bool is_wb = fc->writeback_cache;
205 loff_t oldsize;
206 struct timespec old_mtime;
207
208 spin_lock(&fc->lock);
209 if ((attr_version != 0 && fi->attr_version > attr_version) ||
210 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
211 spin_unlock(&fc->lock);
212 return;
213 }
214
215 old_mtime = inode->i_mtime;
216 fuse_change_attributes_common(inode, attr, attr_valid);
217
218 oldsize = inode->i_size;
219 /*
220 * In case of writeback_cache enabled, the cached writes beyond EOF
221 * extend local i_size without keeping userspace server in sync. So,
222 * attr->size coming from server can be stale. We cannot trust it.
223 */
224 if (!is_wb || !S_ISREG(inode->i_mode))
225 i_size_write(inode, attr->size);
226 spin_unlock(&fc->lock);
227
228 if (!is_wb && S_ISREG(inode->i_mode)) {
229 bool inval = false;
230
231 if (oldsize != attr->size) {
232 truncate_pagecache(inode, attr->size);
233 inval = true;
234 } else if (fc->auto_inval_data) {
235 struct timespec new_mtime = {
236 .tv_sec = attr->mtime,
237 .tv_nsec = attr->mtimensec,
238 };
239
240 /*
241 * Auto inval mode also checks and invalidates if mtime
242 * has changed.
243 */
244 if (!timespec_equal(&old_mtime, &new_mtime))
245 inval = true;
246 }
247
248 if (inval)
249 invalidate_inode_pages2(inode->i_mapping);
250 }
251 }
252
253 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
254 {
255 inode->i_mode = attr->mode & S_IFMT;
256 inode->i_size = attr->size;
257 inode->i_mtime.tv_sec = attr->mtime;
258 inode->i_mtime.tv_nsec = attr->mtimensec;
259 inode->i_ctime.tv_sec = attr->ctime;
260 inode->i_ctime.tv_nsec = attr->ctimensec;
261 if (S_ISREG(inode->i_mode)) {
262 fuse_init_common(inode);
263 fuse_init_file_inode(inode);
264 } else if (S_ISDIR(inode->i_mode))
265 fuse_init_dir(inode);
266 else if (S_ISLNK(inode->i_mode))
267 fuse_init_symlink(inode);
268 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
269 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
270 fuse_init_common(inode);
271 init_special_inode(inode, inode->i_mode,
272 new_decode_dev(attr->rdev));
273 } else
274 BUG();
275 }
276
277 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
278 {
279 u64 nodeid = *(u64 *) _nodeidp;
280 if (get_node_id(inode) == nodeid)
281 return 1;
282 else
283 return 0;
284 }
285
286 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
287 {
288 u64 nodeid = *(u64 *) _nodeidp;
289 get_fuse_inode(inode)->nodeid = nodeid;
290 return 0;
291 }
292
293 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
294 int generation, struct fuse_attr *attr,
295 u64 attr_valid, u64 attr_version)
296 {
297 struct inode *inode;
298 struct fuse_inode *fi;
299 struct fuse_conn *fc = get_fuse_conn_super(sb);
300
301 retry:
302 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
303 if (!inode)
304 return NULL;
305
306 if ((inode->i_state & I_NEW)) {
307 inode->i_flags |= S_NOATIME;
308 if (!fc->writeback_cache || !S_ISREG(attr->mode))
309 inode->i_flags |= S_NOCMTIME;
310 inode->i_generation = generation;
311 fuse_init_inode(inode, attr);
312 unlock_new_inode(inode);
313 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
314 /* Inode has changed type, any I/O on the old should fail */
315 make_bad_inode(inode);
316 iput(inode);
317 goto retry;
318 }
319
320 fi = get_fuse_inode(inode);
321 spin_lock(&fc->lock);
322 fi->nlookup++;
323 spin_unlock(&fc->lock);
324 fuse_change_attributes(inode, attr, attr_valid, attr_version);
325
326 return inode;
327 }
328
329 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
330 loff_t offset, loff_t len)
331 {
332 struct inode *inode;
333 pgoff_t pg_start;
334 pgoff_t pg_end;
335
336 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
337 if (!inode)
338 return -ENOENT;
339
340 fuse_invalidate_attr(inode);
341 if (offset >= 0) {
342 pg_start = offset >> PAGE_CACHE_SHIFT;
343 if (len <= 0)
344 pg_end = -1;
345 else
346 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
347 invalidate_inode_pages2_range(inode->i_mapping,
348 pg_start, pg_end);
349 }
350 iput(inode);
351 return 0;
352 }
353
354 static void fuse_umount_begin(struct super_block *sb)
355 {
356 fuse_abort_conn(get_fuse_conn_super(sb));
357 }
358
359 static void fuse_send_destroy(struct fuse_conn *fc)
360 {
361 struct fuse_req *req = fc->destroy_req;
362 if (req && fc->conn_init) {
363 fc->destroy_req = NULL;
364 req->in.h.opcode = FUSE_DESTROY;
365 req->force = 1;
366 req->background = 0;
367 fuse_request_send(fc, req);
368 fuse_put_request(fc, req);
369 }
370 }
371
372 static void fuse_bdi_destroy(struct fuse_conn *fc)
373 {
374 if (fc->bdi_initialized)
375 bdi_destroy(&fc->bdi);
376 }
377
378 static void fuse_put_super(struct super_block *sb)
379 {
380 struct fuse_conn *fc = get_fuse_conn_super(sb);
381
382 fuse_send_destroy(fc);
383
384 fuse_abort_conn(fc);
385 mutex_lock(&fuse_mutex);
386 list_del(&fc->entry);
387 fuse_ctl_remove_conn(fc);
388 mutex_unlock(&fuse_mutex);
389 fuse_bdi_destroy(fc);
390
391 fuse_conn_put(fc);
392 }
393
394 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
395 {
396 stbuf->f_type = FUSE_SUPER_MAGIC;
397 stbuf->f_bsize = attr->bsize;
398 stbuf->f_frsize = attr->frsize;
399 stbuf->f_blocks = attr->blocks;
400 stbuf->f_bfree = attr->bfree;
401 stbuf->f_bavail = attr->bavail;
402 stbuf->f_files = attr->files;
403 stbuf->f_ffree = attr->ffree;
404 stbuf->f_namelen = attr->namelen;
405 /* fsid is left zero */
406 }
407
408 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
409 {
410 struct super_block *sb = dentry->d_sb;
411 struct fuse_conn *fc = get_fuse_conn_super(sb);
412 FUSE_ARGS(args);
413 struct fuse_statfs_out outarg;
414 int err;
415
416 if (!fuse_allow_current_process(fc)) {
417 buf->f_type = FUSE_SUPER_MAGIC;
418 return 0;
419 }
420
421 memset(&outarg, 0, sizeof(outarg));
422 args.in.numargs = 0;
423 args.in.h.opcode = FUSE_STATFS;
424 args.in.h.nodeid = get_node_id(dentry->d_inode);
425 args.out.numargs = 1;
426 args.out.args[0].size = sizeof(outarg);
427 args.out.args[0].value = &outarg;
428 err = fuse_simple_request(fc, &args);
429 if (!err)
430 convert_fuse_statfs(buf, &outarg.st);
431 return err;
432 }
433
434 enum {
435 OPT_FD,
436 OPT_ROOTMODE,
437 OPT_USER_ID,
438 OPT_GROUP_ID,
439 OPT_DEFAULT_PERMISSIONS,
440 OPT_ALLOW_OTHER,
441 OPT_MAX_READ,
442 OPT_BLKSIZE,
443 OPT_ERR
444 };
445
446 static const match_table_t tokens = {
447 {OPT_FD, "fd=%u"},
448 {OPT_ROOTMODE, "rootmode=%o"},
449 {OPT_USER_ID, "user_id=%u"},
450 {OPT_GROUP_ID, "group_id=%u"},
451 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
452 {OPT_ALLOW_OTHER, "allow_other"},
453 {OPT_MAX_READ, "max_read=%u"},
454 {OPT_BLKSIZE, "blksize=%u"},
455 {OPT_ERR, NULL}
456 };
457
458 static int fuse_match_uint(substring_t *s, unsigned int *res)
459 {
460 int err = -ENOMEM;
461 char *buf = match_strdup(s);
462 if (buf) {
463 err = kstrtouint(buf, 10, res);
464 kfree(buf);
465 }
466 return err;
467 }
468
469 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
470 {
471 char *p;
472 memset(d, 0, sizeof(struct fuse_mount_data));
473 d->max_read = ~0;
474 d->blksize = FUSE_DEFAULT_BLKSIZE;
475
476 while ((p = strsep(&opt, ",")) != NULL) {
477 int token;
478 int value;
479 unsigned uv;
480 substring_t args[MAX_OPT_ARGS];
481 if (!*p)
482 continue;
483
484 token = match_token(p, tokens, args);
485 switch (token) {
486 case OPT_FD:
487 if (match_int(&args[0], &value))
488 return 0;
489 d->fd = value;
490 d->fd_present = 1;
491 break;
492
493 case OPT_ROOTMODE:
494 if (match_octal(&args[0], &value))
495 return 0;
496 if (!fuse_valid_type(value))
497 return 0;
498 d->rootmode = value;
499 d->rootmode_present = 1;
500 break;
501
502 case OPT_USER_ID:
503 if (fuse_match_uint(&args[0], &uv))
504 return 0;
505 d->user_id = make_kuid(current_user_ns(), uv);
506 if (!uid_valid(d->user_id))
507 return 0;
508 d->user_id_present = 1;
509 break;
510
511 case OPT_GROUP_ID:
512 if (fuse_match_uint(&args[0], &uv))
513 return 0;
514 d->group_id = make_kgid(current_user_ns(), uv);
515 if (!gid_valid(d->group_id))
516 return 0;
517 d->group_id_present = 1;
518 break;
519
520 case OPT_DEFAULT_PERMISSIONS:
521 d->flags |= FUSE_DEFAULT_PERMISSIONS;
522 break;
523
524 case OPT_ALLOW_OTHER:
525 d->flags |= FUSE_ALLOW_OTHER;
526 break;
527
528 case OPT_MAX_READ:
529 if (match_int(&args[0], &value))
530 return 0;
531 d->max_read = value;
532 break;
533
534 case OPT_BLKSIZE:
535 if (!is_bdev || match_int(&args[0], &value))
536 return 0;
537 d->blksize = value;
538 break;
539
540 default:
541 return 0;
542 }
543 }
544
545 if (!d->fd_present || !d->rootmode_present ||
546 !d->user_id_present || !d->group_id_present)
547 return 0;
548
549 return 1;
550 }
551
552 static int fuse_show_options(struct seq_file *m, struct dentry *root)
553 {
554 struct super_block *sb = root->d_sb;
555 struct fuse_conn *fc = get_fuse_conn_super(sb);
556
557 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
558 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
559 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
560 seq_puts(m, ",default_permissions");
561 if (fc->flags & FUSE_ALLOW_OTHER)
562 seq_puts(m, ",allow_other");
563 if (fc->max_read != ~0)
564 seq_printf(m, ",max_read=%u", fc->max_read);
565 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
566 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
567 return 0;
568 }
569
570 void fuse_conn_init(struct fuse_conn *fc)
571 {
572 memset(fc, 0, sizeof(*fc));
573 spin_lock_init(&fc->lock);
574 init_rwsem(&fc->killsb);
575 atomic_set(&fc->count, 1);
576 init_waitqueue_head(&fc->waitq);
577 init_waitqueue_head(&fc->blocked_waitq);
578 init_waitqueue_head(&fc->reserved_req_waitq);
579 INIT_LIST_HEAD(&fc->pending);
580 INIT_LIST_HEAD(&fc->processing);
581 INIT_LIST_HEAD(&fc->io);
582 INIT_LIST_HEAD(&fc->interrupts);
583 INIT_LIST_HEAD(&fc->bg_queue);
584 INIT_LIST_HEAD(&fc->entry);
585 fc->forget_list_tail = &fc->forget_list_head;
586 atomic_set(&fc->num_waiting, 0);
587 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
588 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
589 fc->khctr = 0;
590 fc->polled_files = RB_ROOT;
591 fc->reqctr = 0;
592 fc->blocked = 0;
593 fc->initialized = 0;
594 fc->attr_version = 1;
595 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
596 }
597 EXPORT_SYMBOL_GPL(fuse_conn_init);
598
599 void fuse_conn_put(struct fuse_conn *fc)
600 {
601 if (atomic_dec_and_test(&fc->count)) {
602 if (fc->destroy_req)
603 fuse_request_free(fc->destroy_req);
604 fc->release(fc);
605 }
606 }
607 EXPORT_SYMBOL_GPL(fuse_conn_put);
608
609 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
610 {
611 atomic_inc(&fc->count);
612 return fc;
613 }
614 EXPORT_SYMBOL_GPL(fuse_conn_get);
615
616 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
617 {
618 struct fuse_attr attr;
619 memset(&attr, 0, sizeof(attr));
620
621 attr.mode = mode;
622 attr.ino = FUSE_ROOT_ID;
623 attr.nlink = 1;
624 return fuse_iget(sb, 1, 0, &attr, 0, 0);
625 }
626
627 struct fuse_inode_handle {
628 u64 nodeid;
629 u32 generation;
630 };
631
632 static struct dentry *fuse_get_dentry(struct super_block *sb,
633 struct fuse_inode_handle *handle)
634 {
635 struct fuse_conn *fc = get_fuse_conn_super(sb);
636 struct inode *inode;
637 struct dentry *entry;
638 int err = -ESTALE;
639
640 if (handle->nodeid == 0)
641 goto out_err;
642
643 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
644 if (!inode) {
645 struct fuse_entry_out outarg;
646 struct qstr name;
647
648 if (!fc->export_support)
649 goto out_err;
650
651 name.len = 1;
652 name.name = ".";
653 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
654 &inode);
655 if (err && err != -ENOENT)
656 goto out_err;
657 if (err || !inode) {
658 err = -ESTALE;
659 goto out_err;
660 }
661 err = -EIO;
662 if (get_node_id(inode) != handle->nodeid)
663 goto out_iput;
664 }
665 err = -ESTALE;
666 if (inode->i_generation != handle->generation)
667 goto out_iput;
668
669 entry = d_obtain_alias(inode);
670 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
671 fuse_invalidate_entry_cache(entry);
672
673 return entry;
674
675 out_iput:
676 iput(inode);
677 out_err:
678 return ERR_PTR(err);
679 }
680
681 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
682 struct inode *parent)
683 {
684 int len = parent ? 6 : 3;
685 u64 nodeid;
686 u32 generation;
687
688 if (*max_len < len) {
689 *max_len = len;
690 return FILEID_INVALID;
691 }
692
693 nodeid = get_fuse_inode(inode)->nodeid;
694 generation = inode->i_generation;
695
696 fh[0] = (u32)(nodeid >> 32);
697 fh[1] = (u32)(nodeid & 0xffffffff);
698 fh[2] = generation;
699
700 if (parent) {
701 nodeid = get_fuse_inode(parent)->nodeid;
702 generation = parent->i_generation;
703
704 fh[3] = (u32)(nodeid >> 32);
705 fh[4] = (u32)(nodeid & 0xffffffff);
706 fh[5] = generation;
707 }
708
709 *max_len = len;
710 return parent ? 0x82 : 0x81;
711 }
712
713 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
714 struct fid *fid, int fh_len, int fh_type)
715 {
716 struct fuse_inode_handle handle;
717
718 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
719 return NULL;
720
721 handle.nodeid = (u64) fid->raw[0] << 32;
722 handle.nodeid |= (u64) fid->raw[1];
723 handle.generation = fid->raw[2];
724 return fuse_get_dentry(sb, &handle);
725 }
726
727 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
728 struct fid *fid, int fh_len, int fh_type)
729 {
730 struct fuse_inode_handle parent;
731
732 if (fh_type != 0x82 || fh_len < 6)
733 return NULL;
734
735 parent.nodeid = (u64) fid->raw[3] << 32;
736 parent.nodeid |= (u64) fid->raw[4];
737 parent.generation = fid->raw[5];
738 return fuse_get_dentry(sb, &parent);
739 }
740
741 static struct dentry *fuse_get_parent(struct dentry *child)
742 {
743 struct inode *child_inode = child->d_inode;
744 struct fuse_conn *fc = get_fuse_conn(child_inode);
745 struct inode *inode;
746 struct dentry *parent;
747 struct fuse_entry_out outarg;
748 struct qstr name;
749 int err;
750
751 if (!fc->export_support)
752 return ERR_PTR(-ESTALE);
753
754 name.len = 2;
755 name.name = "..";
756 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
757 &name, &outarg, &inode);
758 if (err) {
759 if (err == -ENOENT)
760 return ERR_PTR(-ESTALE);
761 return ERR_PTR(err);
762 }
763
764 parent = d_obtain_alias(inode);
765 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
766 fuse_invalidate_entry_cache(parent);
767
768 return parent;
769 }
770
771 static const struct export_operations fuse_export_operations = {
772 .fh_to_dentry = fuse_fh_to_dentry,
773 .fh_to_parent = fuse_fh_to_parent,
774 .encode_fh = fuse_encode_fh,
775 .get_parent = fuse_get_parent,
776 };
777
778 static const struct super_operations fuse_super_operations = {
779 .alloc_inode = fuse_alloc_inode,
780 .destroy_inode = fuse_destroy_inode,
781 .evict_inode = fuse_evict_inode,
782 .write_inode = fuse_write_inode,
783 .drop_inode = generic_delete_inode,
784 .remount_fs = fuse_remount_fs,
785 .put_super = fuse_put_super,
786 .umount_begin = fuse_umount_begin,
787 .statfs = fuse_statfs,
788 .show_options = fuse_show_options,
789 };
790
791 static void sanitize_global_limit(unsigned *limit)
792 {
793 if (*limit == 0)
794 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
795 sizeof(struct fuse_req);
796
797 if (*limit >= 1 << 16)
798 *limit = (1 << 16) - 1;
799 }
800
801 static int set_global_limit(const char *val, struct kernel_param *kp)
802 {
803 int rv;
804
805 rv = param_set_uint(val, kp);
806 if (rv)
807 return rv;
808
809 sanitize_global_limit((unsigned *)kp->arg);
810
811 return 0;
812 }
813
814 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
815 {
816 int cap_sys_admin = capable(CAP_SYS_ADMIN);
817
818 if (arg->minor < 13)
819 return;
820
821 sanitize_global_limit(&max_user_bgreq);
822 sanitize_global_limit(&max_user_congthresh);
823
824 if (arg->max_background) {
825 fc->max_background = arg->max_background;
826
827 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
828 fc->max_background = max_user_bgreq;
829 }
830 if (arg->congestion_threshold) {
831 fc->congestion_threshold = arg->congestion_threshold;
832
833 if (!cap_sys_admin &&
834 fc->congestion_threshold > max_user_congthresh)
835 fc->congestion_threshold = max_user_congthresh;
836 }
837 }
838
839 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
840 {
841 struct fuse_init_out *arg = &req->misc.init_out;
842
843 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
844 fc->conn_error = 1;
845 else {
846 unsigned long ra_pages;
847
848 process_init_limits(fc, arg);
849
850 if (arg->minor >= 6) {
851 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
852 if (arg->flags & FUSE_ASYNC_READ)
853 fc->async_read = 1;
854 if (!(arg->flags & FUSE_POSIX_LOCKS))
855 fc->no_lock = 1;
856 if (arg->minor >= 17) {
857 if (!(arg->flags & FUSE_FLOCK_LOCKS))
858 fc->no_flock = 1;
859 } else {
860 if (!(arg->flags & FUSE_POSIX_LOCKS))
861 fc->no_flock = 1;
862 }
863 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
864 fc->atomic_o_trunc = 1;
865 if (arg->minor >= 9) {
866 /* LOOKUP has dependency on proto version */
867 if (arg->flags & FUSE_EXPORT_SUPPORT)
868 fc->export_support = 1;
869 }
870 if (arg->flags & FUSE_BIG_WRITES)
871 fc->big_writes = 1;
872 if (arg->flags & FUSE_DONT_MASK)
873 fc->dont_mask = 1;
874 if (arg->flags & FUSE_AUTO_INVAL_DATA)
875 fc->auto_inval_data = 1;
876 if (arg->flags & FUSE_DO_READDIRPLUS) {
877 fc->do_readdirplus = 1;
878 if (arg->flags & FUSE_READDIRPLUS_AUTO)
879 fc->readdirplus_auto = 1;
880 }
881 if (arg->flags & FUSE_ASYNC_DIO)
882 fc->async_dio = 1;
883 if (arg->flags & FUSE_WRITEBACK_CACHE)
884 fc->writeback_cache = 1;
885 if (arg->time_gran && arg->time_gran <= 1000000000)
886 fc->sb->s_time_gran = arg->time_gran;
887 } else {
888 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
889 fc->no_lock = 1;
890 fc->no_flock = 1;
891 }
892
893 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
894 fc->minor = arg->minor;
895 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
896 fc->max_write = max_t(unsigned, 4096, fc->max_write);
897 fc->conn_init = 1;
898 }
899 fuse_set_initialized(fc);
900 wake_up_all(&fc->blocked_waitq);
901 }
902
903 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
904 {
905 struct fuse_init_in *arg = &req->misc.init_in;
906
907 arg->major = FUSE_KERNEL_VERSION;
908 arg->minor = FUSE_KERNEL_MINOR_VERSION;
909 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
910 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
911 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
912 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
913 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
914 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
915 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
916 req->in.h.opcode = FUSE_INIT;
917 req->in.numargs = 1;
918 req->in.args[0].size = sizeof(*arg);
919 req->in.args[0].value = arg;
920 req->out.numargs = 1;
921 /* Variable length argument used for backward compatibility
922 with interface version < 7.5. Rest of init_out is zeroed
923 by do_get_request(), so a short reply is not a problem */
924 req->out.argvar = 1;
925 req->out.args[0].size = sizeof(struct fuse_init_out);
926 req->out.args[0].value = &req->misc.init_out;
927 req->end = process_init_reply;
928 fuse_request_send_background(fc, req);
929 }
930
931 static void fuse_free_conn(struct fuse_conn *fc)
932 {
933 kfree_rcu(fc, rcu);
934 }
935
936 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
937 {
938 int err;
939
940 fc->bdi.name = "fuse";
941 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
942 /* fuse does it's own writeback accounting */
943 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
944
945 err = bdi_init(&fc->bdi);
946 if (err)
947 return err;
948
949 fc->bdi_initialized = 1;
950
951 if (sb->s_bdev) {
952 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
953 MAJOR(fc->dev), MINOR(fc->dev));
954 } else {
955 err = bdi_register_dev(&fc->bdi, fc->dev);
956 }
957
958 if (err)
959 return err;
960
961 /*
962 * For a single fuse filesystem use max 1% of dirty +
963 * writeback threshold.
964 *
965 * This gives about 1M of write buffer for memory maps on a
966 * machine with 1G and 10% dirty_ratio, which should be more
967 * than enough.
968 *
969 * Privileged users can raise it by writing to
970 *
971 * /sys/class/bdi/<bdi>/max_ratio
972 */
973 bdi_set_max_ratio(&fc->bdi, 1);
974
975 return 0;
976 }
977
978 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
979 {
980 struct fuse_conn *fc;
981 struct inode *root;
982 struct fuse_mount_data d;
983 struct file *file;
984 struct dentry *root_dentry;
985 struct fuse_req *init_req;
986 int err;
987 int is_bdev = sb->s_bdev != NULL;
988
989 err = -EINVAL;
990 if (sb->s_flags & MS_MANDLOCK)
991 goto err;
992
993 sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
994
995 if (!parse_fuse_opt(data, &d, is_bdev))
996 goto err;
997
998 if (is_bdev) {
999 #ifdef CONFIG_BLOCK
1000 err = -EINVAL;
1001 if (!sb_set_blocksize(sb, d.blksize))
1002 goto err;
1003 #endif
1004 } else {
1005 sb->s_blocksize = PAGE_CACHE_SIZE;
1006 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1007 }
1008 sb->s_magic = FUSE_SUPER_MAGIC;
1009 sb->s_op = &fuse_super_operations;
1010 sb->s_maxbytes = MAX_LFS_FILESIZE;
1011 sb->s_time_gran = 1;
1012 sb->s_export_op = &fuse_export_operations;
1013
1014 file = fget(d.fd);
1015 err = -EINVAL;
1016 if (!file)
1017 goto err;
1018
1019 if ((file->f_op != &fuse_dev_operations) ||
1020 (file->f_cred->user_ns != &init_user_ns))
1021 goto err_fput;
1022
1023 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1024 err = -ENOMEM;
1025 if (!fc)
1026 goto err_fput;
1027
1028 fuse_conn_init(fc);
1029
1030 fc->dev = sb->s_dev;
1031 fc->sb = sb;
1032 err = fuse_bdi_init(fc, sb);
1033 if (err)
1034 goto err_put_conn;
1035
1036 sb->s_bdi = &fc->bdi;
1037
1038 /* Handle umasking inside the fuse code */
1039 if (sb->s_flags & MS_POSIXACL)
1040 fc->dont_mask = 1;
1041 sb->s_flags |= MS_POSIXACL;
1042
1043 fc->release = fuse_free_conn;
1044 fc->flags = d.flags;
1045 fc->user_id = d.user_id;
1046 fc->group_id = d.group_id;
1047 fc->max_read = max_t(unsigned, 4096, d.max_read);
1048
1049 /* Used by get_root_inode() */
1050 sb->s_fs_info = fc;
1051
1052 err = -ENOMEM;
1053 root = fuse_get_root_inode(sb, d.rootmode);
1054 root_dentry = d_make_root(root);
1055 if (!root_dentry)
1056 goto err_put_conn;
1057 /* only now - we want root dentry with NULL ->d_op */
1058 sb->s_d_op = &fuse_dentry_operations;
1059
1060 init_req = fuse_request_alloc(0);
1061 if (!init_req)
1062 goto err_put_root;
1063 init_req->background = 1;
1064
1065 if (is_bdev) {
1066 fc->destroy_req = fuse_request_alloc(0);
1067 if (!fc->destroy_req)
1068 goto err_free_init_req;
1069 }
1070
1071 mutex_lock(&fuse_mutex);
1072 err = -EINVAL;
1073 if (file->private_data)
1074 goto err_unlock;
1075
1076 err = fuse_ctl_add_conn(fc);
1077 if (err)
1078 goto err_unlock;
1079
1080 list_add_tail(&fc->entry, &fuse_conn_list);
1081 sb->s_root = root_dentry;
1082 fc->connected = 1;
1083 file->private_data = fuse_conn_get(fc);
1084 mutex_unlock(&fuse_mutex);
1085 /*
1086 * atomic_dec_and_test() in fput() provides the necessary
1087 * memory barrier for file->private_data to be visible on all
1088 * CPUs after this
1089 */
1090 fput(file);
1091
1092 fuse_send_init(fc, init_req);
1093
1094 return 0;
1095
1096 err_unlock:
1097 mutex_unlock(&fuse_mutex);
1098 err_free_init_req:
1099 fuse_request_free(init_req);
1100 err_put_root:
1101 dput(root_dentry);
1102 err_put_conn:
1103 fuse_bdi_destroy(fc);
1104 fuse_conn_put(fc);
1105 err_fput:
1106 fput(file);
1107 err:
1108 return err;
1109 }
1110
1111 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1112 int flags, const char *dev_name,
1113 void *raw_data)
1114 {
1115 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1116 }
1117
1118 static void fuse_kill_sb_anon(struct super_block *sb)
1119 {
1120 struct fuse_conn *fc = get_fuse_conn_super(sb);
1121
1122 if (fc) {
1123 down_write(&fc->killsb);
1124 fc->sb = NULL;
1125 up_write(&fc->killsb);
1126 }
1127
1128 kill_anon_super(sb);
1129 }
1130
1131 static struct file_system_type fuse_fs_type = {
1132 .owner = THIS_MODULE,
1133 .name = "fuse",
1134 .fs_flags = FS_HAS_SUBTYPE,
1135 .mount = fuse_mount,
1136 .kill_sb = fuse_kill_sb_anon,
1137 };
1138 MODULE_ALIAS_FS("fuse");
1139
1140 #ifdef CONFIG_BLOCK
1141 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1142 int flags, const char *dev_name,
1143 void *raw_data)
1144 {
1145 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1146 }
1147
1148 static void fuse_kill_sb_blk(struct super_block *sb)
1149 {
1150 struct fuse_conn *fc = get_fuse_conn_super(sb);
1151
1152 if (fc) {
1153 down_write(&fc->killsb);
1154 fc->sb = NULL;
1155 up_write(&fc->killsb);
1156 }
1157
1158 kill_block_super(sb);
1159 }
1160
1161 static struct file_system_type fuseblk_fs_type = {
1162 .owner = THIS_MODULE,
1163 .name = "fuseblk",
1164 .mount = fuse_mount_blk,
1165 .kill_sb = fuse_kill_sb_blk,
1166 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1167 };
1168 MODULE_ALIAS_FS("fuseblk");
1169
1170 static inline int register_fuseblk(void)
1171 {
1172 return register_filesystem(&fuseblk_fs_type);
1173 }
1174
1175 static inline void unregister_fuseblk(void)
1176 {
1177 unregister_filesystem(&fuseblk_fs_type);
1178 }
1179 #else
1180 static inline int register_fuseblk(void)
1181 {
1182 return 0;
1183 }
1184
1185 static inline void unregister_fuseblk(void)
1186 {
1187 }
1188 #endif
1189
1190 static void fuse_inode_init_once(void *foo)
1191 {
1192 struct inode *inode = foo;
1193
1194 inode_init_once(inode);
1195 }
1196
1197 static int __init fuse_fs_init(void)
1198 {
1199 int err;
1200
1201 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1202 sizeof(struct fuse_inode),
1203 0, SLAB_HWCACHE_ALIGN,
1204 fuse_inode_init_once);
1205 err = -ENOMEM;
1206 if (!fuse_inode_cachep)
1207 goto out;
1208
1209 err = register_fuseblk();
1210 if (err)
1211 goto out2;
1212
1213 err = register_filesystem(&fuse_fs_type);
1214 if (err)
1215 goto out3;
1216
1217 return 0;
1218
1219 out3:
1220 unregister_fuseblk();
1221 out2:
1222 kmem_cache_destroy(fuse_inode_cachep);
1223 out:
1224 return err;
1225 }
1226
1227 static void fuse_fs_cleanup(void)
1228 {
1229 unregister_filesystem(&fuse_fs_type);
1230 unregister_fuseblk();
1231
1232 /*
1233 * Make sure all delayed rcu free inodes are flushed before we
1234 * destroy cache.
1235 */
1236 rcu_barrier();
1237 kmem_cache_destroy(fuse_inode_cachep);
1238 }
1239
1240 static struct kobject *fuse_kobj;
1241 static struct kobject *connections_kobj;
1242
1243 static int fuse_sysfs_init(void)
1244 {
1245 int err;
1246
1247 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1248 if (!fuse_kobj) {
1249 err = -ENOMEM;
1250 goto out_err;
1251 }
1252
1253 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1254 if (!connections_kobj) {
1255 err = -ENOMEM;
1256 goto out_fuse_unregister;
1257 }
1258
1259 return 0;
1260
1261 out_fuse_unregister:
1262 kobject_put(fuse_kobj);
1263 out_err:
1264 return err;
1265 }
1266
1267 static void fuse_sysfs_cleanup(void)
1268 {
1269 kobject_put(connections_kobj);
1270 kobject_put(fuse_kobj);
1271 }
1272
1273 static int __init fuse_init(void)
1274 {
1275 int res;
1276
1277 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1278 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1279
1280 INIT_LIST_HEAD(&fuse_conn_list);
1281 res = fuse_fs_init();
1282 if (res)
1283 goto err;
1284
1285 res = fuse_dev_init();
1286 if (res)
1287 goto err_fs_cleanup;
1288
1289 res = fuse_sysfs_init();
1290 if (res)
1291 goto err_dev_cleanup;
1292
1293 res = fuse_ctl_init();
1294 if (res)
1295 goto err_sysfs_cleanup;
1296
1297 sanitize_global_limit(&max_user_bgreq);
1298 sanitize_global_limit(&max_user_congthresh);
1299
1300 return 0;
1301
1302 err_sysfs_cleanup:
1303 fuse_sysfs_cleanup();
1304 err_dev_cleanup:
1305 fuse_dev_cleanup();
1306 err_fs_cleanup:
1307 fuse_fs_cleanup();
1308 err:
1309 return res;
1310 }
1311
1312 static void __exit fuse_exit(void)
1313 {
1314 printk(KERN_DEBUG "fuse exit\n");
1315
1316 fuse_ctl_cleanup();
1317 fuse_sysfs_cleanup();
1318 fuse_fs_cleanup();
1319 fuse_dev_cleanup();
1320 }
1321
1322 module_init(fuse_init);
1323 module_exit(fuse_exit);