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Merge tag 'for-linus-20130628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowe...
[linux-2.6.git] / fs / fuse / inode.c
blob9a0cdde14a088c43e12e5d5fc4ba84257ca98b46
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(&inode->i_data, 0);
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 if (*flags & MS_MANDLOCK)
139 return -EINVAL;
140
141 return 0;
142 }
143
144 /*
145 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
146 * so that it will fit.
147 */
148 static ino_t fuse_squash_ino(u64 ino64)
149 {
150 ino_t ino = (ino_t) ino64;
151 if (sizeof(ino_t) < sizeof(u64))
152 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
153 return ino;
154 }
155
156 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
157 u64 attr_valid)
158 {
159 struct fuse_conn *fc = get_fuse_conn(inode);
160 struct fuse_inode *fi = get_fuse_inode(inode);
161
162 fi->attr_version = ++fc->attr_version;
163 fi->i_time = attr_valid;
164
165 inode->i_ino = fuse_squash_ino(attr->ino);
166 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
167 set_nlink(inode, attr->nlink);
168 inode->i_uid = make_kuid(&init_user_ns, attr->uid);
169 inode->i_gid = make_kgid(&init_user_ns, attr->gid);
170 inode->i_blocks = attr->blocks;
171 inode->i_atime.tv_sec = attr->atime;
172 inode->i_atime.tv_nsec = attr->atimensec;
173 inode->i_mtime.tv_sec = attr->mtime;
174 inode->i_mtime.tv_nsec = attr->mtimensec;
175 inode->i_ctime.tv_sec = attr->ctime;
176 inode->i_ctime.tv_nsec = attr->ctimensec;
177
178 if (attr->blksize != 0)
179 inode->i_blkbits = ilog2(attr->blksize);
180 else
181 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
182
183 /*
184 * Don't set the sticky bit in i_mode, unless we want the VFS
185 * to check permissions. This prevents failures due to the
186 * check in may_delete().
187 */
188 fi->orig_i_mode = inode->i_mode;
189 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
190 inode->i_mode &= ~S_ISVTX;
191
192 fi->orig_ino = attr->ino;
193 }
194
195 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
196 u64 attr_valid, u64 attr_version)
197 {
198 struct fuse_conn *fc = get_fuse_conn(inode);
199 struct fuse_inode *fi = get_fuse_inode(inode);
200 loff_t oldsize;
201 struct timespec old_mtime;
202
203 spin_lock(&fc->lock);
204 if (attr_version != 0 && fi->attr_version > attr_version) {
205 spin_unlock(&fc->lock);
206 return;
207 }
208
209 old_mtime = inode->i_mtime;
210 fuse_change_attributes_common(inode, attr, attr_valid);
211
212 oldsize = inode->i_size;
213 i_size_write(inode, attr->size);
214 spin_unlock(&fc->lock);
215
216 if (S_ISREG(inode->i_mode)) {
217 bool inval = false;
218
219 if (oldsize != attr->size) {
220 truncate_pagecache(inode, oldsize, attr->size);
221 inval = true;
222 } else if (fc->auto_inval_data) {
223 struct timespec new_mtime = {
224 .tv_sec = attr->mtime,
225 .tv_nsec = attr->mtimensec,
226 };
227
228 /*
229 * Auto inval mode also checks and invalidates if mtime
230 * has changed.
231 */
232 if (!timespec_equal(&old_mtime, &new_mtime))
233 inval = true;
234 }
235
236 if (inval)
237 invalidate_inode_pages2(inode->i_mapping);
238 }
239 }
240
241 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
242 {
243 inode->i_mode = attr->mode & S_IFMT;
244 inode->i_size = attr->size;
245 if (S_ISREG(inode->i_mode)) {
246 fuse_init_common(inode);
247 fuse_init_file_inode(inode);
248 } else if (S_ISDIR(inode->i_mode))
249 fuse_init_dir(inode);
250 else if (S_ISLNK(inode->i_mode))
251 fuse_init_symlink(inode);
252 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
253 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
254 fuse_init_common(inode);
255 init_special_inode(inode, inode->i_mode,
256 new_decode_dev(attr->rdev));
257 } else
258 BUG();
259 }
260
261 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
262 {
263 u64 nodeid = *(u64 *) _nodeidp;
264 if (get_node_id(inode) == nodeid)
265 return 1;
266 else
267 return 0;
268 }
269
270 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
271 {
272 u64 nodeid = *(u64 *) _nodeidp;
273 get_fuse_inode(inode)->nodeid = nodeid;
274 return 0;
275 }
276
277 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
278 int generation, struct fuse_attr *attr,
279 u64 attr_valid, u64 attr_version)
280 {
281 struct inode *inode;
282 struct fuse_inode *fi;
283 struct fuse_conn *fc = get_fuse_conn_super(sb);
284
285 retry:
286 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
287 if (!inode)
288 return NULL;
289
290 if ((inode->i_state & I_NEW)) {
291 inode->i_flags |= S_NOATIME|S_NOCMTIME;
292 inode->i_generation = generation;
293 inode->i_data.backing_dev_info = &fc->bdi;
294 fuse_init_inode(inode, attr);
295 unlock_new_inode(inode);
296 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
297 /* Inode has changed type, any I/O on the old should fail */
298 make_bad_inode(inode);
299 iput(inode);
300 goto retry;
301 }
302
303 fi = get_fuse_inode(inode);
304 spin_lock(&fc->lock);
305 fi->nlookup++;
306 spin_unlock(&fc->lock);
307 fuse_change_attributes(inode, attr, attr_valid, attr_version);
308
309 return inode;
310 }
311
312 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
313 loff_t offset, loff_t len)
314 {
315 struct inode *inode;
316 pgoff_t pg_start;
317 pgoff_t pg_end;
318
319 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
320 if (!inode)
321 return -ENOENT;
322
323 fuse_invalidate_attr(inode);
324 if (offset >= 0) {
325 pg_start = offset >> PAGE_CACHE_SHIFT;
326 if (len <= 0)
327 pg_end = -1;
328 else
329 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
330 invalidate_inode_pages2_range(inode->i_mapping,
331 pg_start, pg_end);
332 }
333 iput(inode);
334 return 0;
335 }
336
337 static void fuse_umount_begin(struct super_block *sb)
338 {
339 fuse_abort_conn(get_fuse_conn_super(sb));
340 }
341
342 static void fuse_send_destroy(struct fuse_conn *fc)
343 {
344 struct fuse_req *req = fc->destroy_req;
345 if (req && fc->conn_init) {
346 fc->destroy_req = NULL;
347 req->in.h.opcode = FUSE_DESTROY;
348 req->force = 1;
349 req->background = 0;
350 fuse_request_send(fc, req);
351 fuse_put_request(fc, req);
352 }
353 }
354
355 static void fuse_bdi_destroy(struct fuse_conn *fc)
356 {
357 if (fc->bdi_initialized)
358 bdi_destroy(&fc->bdi);
359 }
360
361 void fuse_conn_kill(struct fuse_conn *fc)
362 {
363 spin_lock(&fc->lock);
364 fc->connected = 0;
365 fc->blocked = 0;
366 fc->initialized = 1;
367 spin_unlock(&fc->lock);
368 /* Flush all readers on this fs */
369 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
370 wake_up_all(&fc->waitq);
371 wake_up_all(&fc->blocked_waitq);
372 wake_up_all(&fc->reserved_req_waitq);
373 }
374 EXPORT_SYMBOL_GPL(fuse_conn_kill);
375
376 static void fuse_put_super(struct super_block *sb)
377 {
378 struct fuse_conn *fc = get_fuse_conn_super(sb);
379
380 fuse_send_destroy(fc);
381
382 fuse_conn_kill(fc);
383 mutex_lock(&fuse_mutex);
384 list_del(&fc->entry);
385 fuse_ctl_remove_conn(fc);
386 mutex_unlock(&fuse_mutex);
387 fuse_bdi_destroy(fc);
388
389 fuse_conn_put(fc);
390 }
391
392 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
393 {
394 stbuf->f_type = FUSE_SUPER_MAGIC;
395 stbuf->f_bsize = attr->bsize;
396 stbuf->f_frsize = attr->frsize;
397 stbuf->f_blocks = attr->blocks;
398 stbuf->f_bfree = attr->bfree;
399 stbuf->f_bavail = attr->bavail;
400 stbuf->f_files = attr->files;
401 stbuf->f_ffree = attr->ffree;
402 stbuf->f_namelen = attr->namelen;
403 /* fsid is left zero */
404 }
405
406 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
407 {
408 struct super_block *sb = dentry->d_sb;
409 struct fuse_conn *fc = get_fuse_conn_super(sb);
410 struct fuse_req *req;
411 struct fuse_statfs_out outarg;
412 int err;
413
414 if (!fuse_allow_current_process(fc)) {
415 buf->f_type = FUSE_SUPER_MAGIC;
416 return 0;
417 }
418
419 req = fuse_get_req_nopages(fc);
420 if (IS_ERR(req))
421 return PTR_ERR(req);
422
423 memset(&outarg, 0, sizeof(outarg));
424 req->in.numargs = 0;
425 req->in.h.opcode = FUSE_STATFS;
426 req->in.h.nodeid = get_node_id(dentry->d_inode);
427 req->out.numargs = 1;
428 req->out.args[0].size =
429 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
430 req->out.args[0].value = &outarg;
431 fuse_request_send(fc, req);
432 err = req->out.h.error;
433 if (!err)
434 convert_fuse_statfs(buf, &outarg.st);
435 fuse_put_request(fc, req);
436 return err;
437 }
438
439 enum {
440 OPT_FD,
441 OPT_ROOTMODE,
442 OPT_USER_ID,
443 OPT_GROUP_ID,
444 OPT_DEFAULT_PERMISSIONS,
445 OPT_ALLOW_OTHER,
446 OPT_MAX_READ,
447 OPT_BLKSIZE,
448 OPT_ERR
449 };
450
451 static const match_table_t tokens = {
452 {OPT_FD, "fd=%u"},
453 {OPT_ROOTMODE, "rootmode=%o"},
454 {OPT_USER_ID, "user_id=%u"},
455 {OPT_GROUP_ID, "group_id=%u"},
456 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
457 {OPT_ALLOW_OTHER, "allow_other"},
458 {OPT_MAX_READ, "max_read=%u"},
459 {OPT_BLKSIZE, "blksize=%u"},
460 {OPT_ERR, NULL}
461 };
462
463 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
464 {
465 char *p;
466 memset(d, 0, sizeof(struct fuse_mount_data));
467 d->max_read = ~0;
468 d->blksize = FUSE_DEFAULT_BLKSIZE;
469
470 while ((p = strsep(&opt, ",")) != NULL) {
471 int token;
472 int value;
473 substring_t args[MAX_OPT_ARGS];
474 if (!*p)
475 continue;
476
477 token = match_token(p, tokens, args);
478 switch (token) {
479 case OPT_FD:
480 if (match_int(&args[0], &value))
481 return 0;
482 d->fd = value;
483 d->fd_present = 1;
484 break;
485
486 case OPT_ROOTMODE:
487 if (match_octal(&args[0], &value))
488 return 0;
489 if (!fuse_valid_type(value))
490 return 0;
491 d->rootmode = value;
492 d->rootmode_present = 1;
493 break;
494
495 case OPT_USER_ID:
496 if (match_int(&args[0], &value))
497 return 0;
498 d->user_id = make_kuid(current_user_ns(), value);
499 if (!uid_valid(d->user_id))
500 return 0;
501 d->user_id_present = 1;
502 break;
503
504 case OPT_GROUP_ID:
505 if (match_int(&args[0], &value))
506 return 0;
507 d->group_id = make_kgid(current_user_ns(), value);
508 if (!gid_valid(d->group_id))
509 return 0;
510 d->group_id_present = 1;
511 break;
512
513 case OPT_DEFAULT_PERMISSIONS:
514 d->flags |= FUSE_DEFAULT_PERMISSIONS;
515 break;
516
517 case OPT_ALLOW_OTHER:
518 d->flags |= FUSE_ALLOW_OTHER;
519 break;
520
521 case OPT_MAX_READ:
522 if (match_int(&args[0], &value))
523 return 0;
524 d->max_read = value;
525 break;
526
527 case OPT_BLKSIZE:
528 if (!is_bdev || match_int(&args[0], &value))
529 return 0;
530 d->blksize = value;
531 break;
532
533 default:
534 return 0;
535 }
536 }
537
538 if (!d->fd_present || !d->rootmode_present ||
539 !d->user_id_present || !d->group_id_present)
540 return 0;
541
542 return 1;
543 }
544
545 static int fuse_show_options(struct seq_file *m, struct dentry *root)
546 {
547 struct super_block *sb = root->d_sb;
548 struct fuse_conn *fc = get_fuse_conn_super(sb);
549
550 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
551 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
552 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
553 seq_puts(m, ",default_permissions");
554 if (fc->flags & FUSE_ALLOW_OTHER)
555 seq_puts(m, ",allow_other");
556 if (fc->max_read != ~0)
557 seq_printf(m, ",max_read=%u", fc->max_read);
558 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
559 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
560 return 0;
561 }
562
563 void fuse_conn_init(struct fuse_conn *fc)
564 {
565 memset(fc, 0, sizeof(*fc));
566 spin_lock_init(&fc->lock);
567 mutex_init(&fc->inst_mutex);
568 init_rwsem(&fc->killsb);
569 atomic_set(&fc->count, 1);
570 init_waitqueue_head(&fc->waitq);
571 init_waitqueue_head(&fc->blocked_waitq);
572 init_waitqueue_head(&fc->reserved_req_waitq);
573 INIT_LIST_HEAD(&fc->pending);
574 INIT_LIST_HEAD(&fc->processing);
575 INIT_LIST_HEAD(&fc->io);
576 INIT_LIST_HEAD(&fc->interrupts);
577 INIT_LIST_HEAD(&fc->bg_queue);
578 INIT_LIST_HEAD(&fc->entry);
579 fc->forget_list_tail = &fc->forget_list_head;
580 atomic_set(&fc->num_waiting, 0);
581 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
582 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
583 fc->khctr = 0;
584 fc->polled_files = RB_ROOT;
585 fc->reqctr = 0;
586 fc->blocked = 0;
587 fc->initialized = 0;
588 fc->attr_version = 1;
589 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
590 }
591 EXPORT_SYMBOL_GPL(fuse_conn_init);
592
593 void fuse_conn_put(struct fuse_conn *fc)
594 {
595 if (atomic_dec_and_test(&fc->count)) {
596 if (fc->destroy_req)
597 fuse_request_free(fc->destroy_req);
598 mutex_destroy(&fc->inst_mutex);
599 fc->release(fc);
600 }
601 }
602 EXPORT_SYMBOL_GPL(fuse_conn_put);
603
604 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
605 {
606 atomic_inc(&fc->count);
607 return fc;
608 }
609 EXPORT_SYMBOL_GPL(fuse_conn_get);
610
611 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
612 {
613 struct fuse_attr attr;
614 memset(&attr, 0, sizeof(attr));
615
616 attr.mode = mode;
617 attr.ino = FUSE_ROOT_ID;
618 attr.nlink = 1;
619 return fuse_iget(sb, 1, 0, &attr, 0, 0);
620 }
621
622 struct fuse_inode_handle {
623 u64 nodeid;
624 u32 generation;
625 };
626
627 static struct dentry *fuse_get_dentry(struct super_block *sb,
628 struct fuse_inode_handle *handle)
629 {
630 struct fuse_conn *fc = get_fuse_conn_super(sb);
631 struct inode *inode;
632 struct dentry *entry;
633 int err = -ESTALE;
634
635 if (handle->nodeid == 0)
636 goto out_err;
637
638 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
639 if (!inode) {
640 struct fuse_entry_out outarg;
641 struct qstr name;
642
643 if (!fc->export_support)
644 goto out_err;
645
646 name.len = 1;
647 name.name = ".";
648 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
649 &inode);
650 if (err && err != -ENOENT)
651 goto out_err;
652 if (err || !inode) {
653 err = -ESTALE;
654 goto out_err;
655 }
656 err = -EIO;
657 if (get_node_id(inode) != handle->nodeid)
658 goto out_iput;
659 }
660 err = -ESTALE;
661 if (inode->i_generation != handle->generation)
662 goto out_iput;
663
664 entry = d_obtain_alias(inode);
665 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
666 fuse_invalidate_entry_cache(entry);
667
668 return entry;
669
670 out_iput:
671 iput(inode);
672 out_err:
673 return ERR_PTR(err);
674 }
675
676 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
677 struct inode *parent)
678 {
679 int len = parent ? 6 : 3;
680 u64 nodeid;
681 u32 generation;
682
683 if (*max_len < len) {
684 *max_len = len;
685 return FILEID_INVALID;
686 }
687
688 nodeid = get_fuse_inode(inode)->nodeid;
689 generation = inode->i_generation;
690
691 fh[0] = (u32)(nodeid >> 32);
692 fh[1] = (u32)(nodeid & 0xffffffff);
693 fh[2] = generation;
694
695 if (parent) {
696 nodeid = get_fuse_inode(parent)->nodeid;
697 generation = parent->i_generation;
698
699 fh[3] = (u32)(nodeid >> 32);
700 fh[4] = (u32)(nodeid & 0xffffffff);
701 fh[5] = generation;
702 }
703
704 *max_len = len;
705 return parent ? 0x82 : 0x81;
706 }
707
708 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
709 struct fid *fid, int fh_len, int fh_type)
710 {
711 struct fuse_inode_handle handle;
712
713 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
714 return NULL;
715
716 handle.nodeid = (u64) fid->raw[0] << 32;
717 handle.nodeid |= (u64) fid->raw[1];
718 handle.generation = fid->raw[2];
719 return fuse_get_dentry(sb, &handle);
720 }
721
722 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
723 struct fid *fid, int fh_len, int fh_type)
724 {
725 struct fuse_inode_handle parent;
726
727 if (fh_type != 0x82 || fh_len < 6)
728 return NULL;
729
730 parent.nodeid = (u64) fid->raw[3] << 32;
731 parent.nodeid |= (u64) fid->raw[4];
732 parent.generation = fid->raw[5];
733 return fuse_get_dentry(sb, &parent);
734 }
735
736 static struct dentry *fuse_get_parent(struct dentry *child)
737 {
738 struct inode *child_inode = child->d_inode;
739 struct fuse_conn *fc = get_fuse_conn(child_inode);
740 struct inode *inode;
741 struct dentry *parent;
742 struct fuse_entry_out outarg;
743 struct qstr name;
744 int err;
745
746 if (!fc->export_support)
747 return ERR_PTR(-ESTALE);
748
749 name.len = 2;
750 name.name = "..";
751 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
752 &name, &outarg, &inode);
753 if (err) {
754 if (err == -ENOENT)
755 return ERR_PTR(-ESTALE);
756 return ERR_PTR(err);
757 }
758
759 parent = d_obtain_alias(inode);
760 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
761 fuse_invalidate_entry_cache(parent);
762
763 return parent;
764 }
765
766 static const struct export_operations fuse_export_operations = {
767 .fh_to_dentry = fuse_fh_to_dentry,
768 .fh_to_parent = fuse_fh_to_parent,
769 .encode_fh = fuse_encode_fh,
770 .get_parent = fuse_get_parent,
771 };
772
773 static const struct super_operations fuse_super_operations = {
774 .alloc_inode = fuse_alloc_inode,
775 .destroy_inode = fuse_destroy_inode,
776 .evict_inode = fuse_evict_inode,
777 .drop_inode = generic_delete_inode,
778 .remount_fs = fuse_remount_fs,
779 .put_super = fuse_put_super,
780 .umount_begin = fuse_umount_begin,
781 .statfs = fuse_statfs,
782 .show_options = fuse_show_options,
783 };
784
785 static void sanitize_global_limit(unsigned *limit)
786 {
787 if (*limit == 0)
788 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
789 sizeof(struct fuse_req);
790
791 if (*limit >= 1 << 16)
792 *limit = (1 << 16) - 1;
793 }
794
795 static int set_global_limit(const char *val, struct kernel_param *kp)
796 {
797 int rv;
798
799 rv = param_set_uint(val, kp);
800 if (rv)
801 return rv;
802
803 sanitize_global_limit((unsigned *)kp->arg);
804
805 return 0;
806 }
807
808 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
809 {
810 int cap_sys_admin = capable(CAP_SYS_ADMIN);
811
812 if (arg->minor < 13)
813 return;
814
815 sanitize_global_limit(&max_user_bgreq);
816 sanitize_global_limit(&max_user_congthresh);
817
818 if (arg->max_background) {
819 fc->max_background = arg->max_background;
820
821 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
822 fc->max_background = max_user_bgreq;
823 }
824 if (arg->congestion_threshold) {
825 fc->congestion_threshold = arg->congestion_threshold;
826
827 if (!cap_sys_admin &&
828 fc->congestion_threshold > max_user_congthresh)
829 fc->congestion_threshold = max_user_congthresh;
830 }
831 }
832
833 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
834 {
835 struct fuse_init_out *arg = &req->misc.init_out;
836
837 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
838 fc->conn_error = 1;
839 else {
840 unsigned long ra_pages;
841
842 process_init_limits(fc, arg);
843
844 if (arg->minor >= 6) {
845 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
846 if (arg->flags & FUSE_ASYNC_READ)
847 fc->async_read = 1;
848 if (!(arg->flags & FUSE_POSIX_LOCKS))
849 fc->no_lock = 1;
850 if (arg->minor >= 17) {
851 if (!(arg->flags & FUSE_FLOCK_LOCKS))
852 fc->no_flock = 1;
853 } else {
854 if (!(arg->flags & FUSE_POSIX_LOCKS))
855 fc->no_flock = 1;
856 }
857 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
858 fc->atomic_o_trunc = 1;
859 if (arg->minor >= 9) {
860 /* LOOKUP has dependency on proto version */
861 if (arg->flags & FUSE_EXPORT_SUPPORT)
862 fc->export_support = 1;
863 }
864 if (arg->flags & FUSE_BIG_WRITES)
865 fc->big_writes = 1;
866 if (arg->flags & FUSE_DONT_MASK)
867 fc->dont_mask = 1;
868 if (arg->flags & FUSE_AUTO_INVAL_DATA)
869 fc->auto_inval_data = 1;
870 if (arg->flags & FUSE_DO_READDIRPLUS) {
871 fc->do_readdirplus = 1;
872 if (arg->flags & FUSE_READDIRPLUS_AUTO)
873 fc->readdirplus_auto = 1;
874 }
875 if (arg->flags & FUSE_ASYNC_DIO)
876 fc->async_dio = 1;
877 } else {
878 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
879 fc->no_lock = 1;
880 fc->no_flock = 1;
881 }
882
883 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
884 fc->minor = arg->minor;
885 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
886 fc->max_write = max_t(unsigned, 4096, fc->max_write);
887 fc->conn_init = 1;
888 }
889 fc->initialized = 1;
890 wake_up_all(&fc->blocked_waitq);
891 }
892
893 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
894 {
895 struct fuse_init_in *arg = &req->misc.init_in;
896
897 arg->major = FUSE_KERNEL_VERSION;
898 arg->minor = FUSE_KERNEL_MINOR_VERSION;
899 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
900 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
901 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
902 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
903 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
904 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
905 req->in.h.opcode = FUSE_INIT;
906 req->in.numargs = 1;
907 req->in.args[0].size = sizeof(*arg);
908 req->in.args[0].value = arg;
909 req->out.numargs = 1;
910 /* Variable length argument used for backward compatibility
911 with interface version < 7.5. Rest of init_out is zeroed
912 by do_get_request(), so a short reply is not a problem */
913 req->out.argvar = 1;
914 req->out.args[0].size = sizeof(struct fuse_init_out);
915 req->out.args[0].value = &req->misc.init_out;
916 req->end = process_init_reply;
917 fuse_request_send_background(fc, req);
918 }
919
920 static void fuse_free_conn(struct fuse_conn *fc)
921 {
922 kfree(fc);
923 }
924
925 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
926 {
927 int err;
928
929 fc->bdi.name = "fuse";
930 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
931 /* fuse does it's own writeback accounting */
932 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
933
934 err = bdi_init(&fc->bdi);
935 if (err)
936 return err;
937
938 fc->bdi_initialized = 1;
939
940 if (sb->s_bdev) {
941 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
942 MAJOR(fc->dev), MINOR(fc->dev));
943 } else {
944 err = bdi_register_dev(&fc->bdi, fc->dev);
945 }
946
947 if (err)
948 return err;
949
950 /*
951 * For a single fuse filesystem use max 1% of dirty +
952 * writeback threshold.
953 *
954 * This gives about 1M of write buffer for memory maps on a
955 * machine with 1G and 10% dirty_ratio, which should be more
956 * than enough.
957 *
958 * Privileged users can raise it by writing to
959 *
960 * /sys/class/bdi/<bdi>/max_ratio
961 */
962 bdi_set_max_ratio(&fc->bdi, 1);
963
964 return 0;
965 }
966
967 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
968 {
969 struct fuse_conn *fc;
970 struct inode *root;
971 struct fuse_mount_data d;
972 struct file *file;
973 struct dentry *root_dentry;
974 struct fuse_req *init_req;
975 int err;
976 int is_bdev = sb->s_bdev != NULL;
977
978 err = -EINVAL;
979 if (sb->s_flags & MS_MANDLOCK)
980 goto err;
981
982 sb->s_flags &= ~MS_NOSEC;
983
984 if (!parse_fuse_opt((char *) data, &d, is_bdev))
985 goto err;
986
987 if (is_bdev) {
988 #ifdef CONFIG_BLOCK
989 err = -EINVAL;
990 if (!sb_set_blocksize(sb, d.blksize))
991 goto err;
992 #endif
993 } else {
994 sb->s_blocksize = PAGE_CACHE_SIZE;
995 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
996 }
997 sb->s_magic = FUSE_SUPER_MAGIC;
998 sb->s_op = &fuse_super_operations;
999 sb->s_maxbytes = MAX_LFS_FILESIZE;
1000 sb->s_time_gran = 1;
1001 sb->s_export_op = &fuse_export_operations;
1002
1003 file = fget(d.fd);
1004 err = -EINVAL;
1005 if (!file)
1006 goto err;
1007
1008 if ((file->f_op != &fuse_dev_operations) ||
1009 (file->f_cred->user_ns != &init_user_ns))
1010 goto err_fput;
1011
1012 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1013 err = -ENOMEM;
1014 if (!fc)
1015 goto err_fput;
1016
1017 fuse_conn_init(fc);
1018
1019 fc->dev = sb->s_dev;
1020 fc->sb = sb;
1021 err = fuse_bdi_init(fc, sb);
1022 if (err)
1023 goto err_put_conn;
1024
1025 sb->s_bdi = &fc->bdi;
1026
1027 /* Handle umasking inside the fuse code */
1028 if (sb->s_flags & MS_POSIXACL)
1029 fc->dont_mask = 1;
1030 sb->s_flags |= MS_POSIXACL;
1031
1032 fc->release = fuse_free_conn;
1033 fc->flags = d.flags;
1034 fc->user_id = d.user_id;
1035 fc->group_id = d.group_id;
1036 fc->max_read = max_t(unsigned, 4096, d.max_read);
1037
1038 /* Used by get_root_inode() */
1039 sb->s_fs_info = fc;
1040
1041 err = -ENOMEM;
1042 root = fuse_get_root_inode(sb, d.rootmode);
1043 root_dentry = d_make_root(root);
1044 if (!root_dentry)
1045 goto err_put_conn;
1046 /* only now - we want root dentry with NULL ->d_op */
1047 sb->s_d_op = &fuse_dentry_operations;
1048
1049 init_req = fuse_request_alloc(0);
1050 if (!init_req)
1051 goto err_put_root;
1052 init_req->background = 1;
1053
1054 if (is_bdev) {
1055 fc->destroy_req = fuse_request_alloc(0);
1056 if (!fc->destroy_req)
1057 goto err_free_init_req;
1058 }
1059
1060 mutex_lock(&fuse_mutex);
1061 err = -EINVAL;
1062 if (file->private_data)
1063 goto err_unlock;
1064
1065 err = fuse_ctl_add_conn(fc);
1066 if (err)
1067 goto err_unlock;
1068
1069 list_add_tail(&fc->entry, &fuse_conn_list);
1070 sb->s_root = root_dentry;
1071 fc->connected = 1;
1072 file->private_data = fuse_conn_get(fc);
1073 mutex_unlock(&fuse_mutex);
1074 /*
1075 * atomic_dec_and_test() in fput() provides the necessary
1076 * memory barrier for file->private_data to be visible on all
1077 * CPUs after this
1078 */
1079 fput(file);
1080
1081 fuse_send_init(fc, init_req);
1082
1083 return 0;
1084
1085 err_unlock:
1086 mutex_unlock(&fuse_mutex);
1087 err_free_init_req:
1088 fuse_request_free(init_req);
1089 err_put_root:
1090 dput(root_dentry);
1091 err_put_conn:
1092 fuse_bdi_destroy(fc);
1093 fuse_conn_put(fc);
1094 err_fput:
1095 fput(file);
1096 err:
1097 return err;
1098 }
1099
1100 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1101 int flags, const char *dev_name,
1102 void *raw_data)
1103 {
1104 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1105 }
1106
1107 static void fuse_kill_sb_anon(struct super_block *sb)
1108 {
1109 struct fuse_conn *fc = get_fuse_conn_super(sb);
1110
1111 if (fc) {
1112 down_write(&fc->killsb);
1113 fc->sb = NULL;
1114 up_write(&fc->killsb);
1115 }
1116
1117 kill_anon_super(sb);
1118 }
1119
1120 static struct file_system_type fuse_fs_type = {
1121 .owner = THIS_MODULE,
1122 .name = "fuse",
1123 .fs_flags = FS_HAS_SUBTYPE,
1124 .mount = fuse_mount,
1125 .kill_sb = fuse_kill_sb_anon,
1126 };
1127 MODULE_ALIAS_FS("fuse");
1128
1129 #ifdef CONFIG_BLOCK
1130 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1131 int flags, const char *dev_name,
1132 void *raw_data)
1133 {
1134 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1135 }
1136
1137 static void fuse_kill_sb_blk(struct super_block *sb)
1138 {
1139 struct fuse_conn *fc = get_fuse_conn_super(sb);
1140
1141 if (fc) {
1142 down_write(&fc->killsb);
1143 fc->sb = NULL;
1144 up_write(&fc->killsb);
1145 }
1146
1147 kill_block_super(sb);
1148 }
1149
1150 static struct file_system_type fuseblk_fs_type = {
1151 .owner = THIS_MODULE,
1152 .name = "fuseblk",
1153 .mount = fuse_mount_blk,
1154 .kill_sb = fuse_kill_sb_blk,
1155 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1156 };
1157 MODULE_ALIAS_FS("fuseblk");
1158
1159 static inline int register_fuseblk(void)
1160 {
1161 return register_filesystem(&fuseblk_fs_type);
1162 }
1163
1164 static inline void unregister_fuseblk(void)
1165 {
1166 unregister_filesystem(&fuseblk_fs_type);
1167 }
1168 #else
1169 static inline int register_fuseblk(void)
1170 {
1171 return 0;
1172 }
1173
1174 static inline void unregister_fuseblk(void)
1175 {
1176 }
1177 #endif
1178
1179 static void fuse_inode_init_once(void *foo)
1180 {
1181 struct inode *inode = foo;
1182
1183 inode_init_once(inode);
1184 }
1185
1186 static int __init fuse_fs_init(void)
1187 {
1188 int err;
1189
1190 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1191 sizeof(struct fuse_inode),
1192 0, SLAB_HWCACHE_ALIGN,
1193 fuse_inode_init_once);
1194 err = -ENOMEM;
1195 if (!fuse_inode_cachep)
1196 goto out;
1197
1198 err = register_fuseblk();
1199 if (err)
1200 goto out2;
1201
1202 err = register_filesystem(&fuse_fs_type);
1203 if (err)
1204 goto out3;
1205
1206 return 0;
1207
1208 out3:
1209 unregister_fuseblk();
1210 out2:
1211 kmem_cache_destroy(fuse_inode_cachep);
1212 out:
1213 return err;
1214 }
1215
1216 static void fuse_fs_cleanup(void)
1217 {
1218 unregister_filesystem(&fuse_fs_type);
1219 unregister_fuseblk();
1220
1221 /*
1222 * Make sure all delayed rcu free inodes are flushed before we
1223 * destroy cache.
1224 */
1225 rcu_barrier();
1226 kmem_cache_destroy(fuse_inode_cachep);
1227 }
1228
1229 static struct kobject *fuse_kobj;
1230 static struct kobject *connections_kobj;
1231
1232 static int fuse_sysfs_init(void)
1233 {
1234 int err;
1235
1236 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1237 if (!fuse_kobj) {
1238 err = -ENOMEM;
1239 goto out_err;
1240 }
1241
1242 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1243 if (!connections_kobj) {
1244 err = -ENOMEM;
1245 goto out_fuse_unregister;
1246 }
1247
1248 return 0;
1249
1250 out_fuse_unregister:
1251 kobject_put(fuse_kobj);
1252 out_err:
1253 return err;
1254 }
1255
1256 static void fuse_sysfs_cleanup(void)
1257 {
1258 kobject_put(connections_kobj);
1259 kobject_put(fuse_kobj);
1260 }
1261
1262 static int __init fuse_init(void)
1263 {
1264 int res;
1265
1266 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1267 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1268
1269 INIT_LIST_HEAD(&fuse_conn_list);
1270 res = fuse_fs_init();
1271 if (res)
1272 goto err;
1273
1274 res = fuse_dev_init();
1275 if (res)
1276 goto err_fs_cleanup;
1277
1278 res = fuse_sysfs_init();
1279 if (res)
1280 goto err_dev_cleanup;
1281
1282 res = fuse_ctl_init();
1283 if (res)
1284 goto err_sysfs_cleanup;
1285
1286 sanitize_global_limit(&max_user_bgreq);
1287 sanitize_global_limit(&max_user_congthresh);
1288
1289 return 0;
1290
1291 err_sysfs_cleanup:
1292 fuse_sysfs_cleanup();
1293 err_dev_cleanup:
1294 fuse_dev_cleanup();
1295 err_fs_cleanup:
1296 fuse_fs_cleanup();
1297 err:
1298 return res;
1299 }
1300
1301 static void __exit fuse_exit(void)
1302 {
1303 printk(KERN_DEBUG "fuse exit\n");
1304
1305 fuse_ctl_cleanup();
1306 fuse_sysfs_cleanup();
1307 fuse_fs_cleanup();
1308 fuse_dev_cleanup();
1309 }
1310
1311 module_init(fuse_init);
1312 module_exit(fuse_exit);
Linus' kernel tree