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Linux 3.12.39
[linux/fpc-iii.git] / fs / fuse / inode.c
blob4937d4b512531bd5e2831837eb2b8d7aed89d00e
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 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
206 spin_unlock(&fc->lock);
207 return;
208 }
209
210 old_mtime = inode->i_mtime;
211 fuse_change_attributes_common(inode, attr, attr_valid);
212
213 oldsize = inode->i_size;
214 i_size_write(inode, attr->size);
215 spin_unlock(&fc->lock);
216
217 if (S_ISREG(inode->i_mode)) {
218 bool inval = false;
219
220 if (oldsize != attr->size) {
221 truncate_pagecache(inode, attr->size);
222 inval = true;
223 } else if (fc->auto_inval_data) {
224 struct timespec new_mtime = {
225 .tv_sec = attr->mtime,
226 .tv_nsec = attr->mtimensec,
227 };
228
229 /*
230 * Auto inval mode also checks and invalidates if mtime
231 * has changed.
232 */
233 if (!timespec_equal(&old_mtime, &new_mtime))
234 inval = true;
235 }
236
237 if (inval)
238 invalidate_inode_pages2(inode->i_mapping);
239 }
240 }
241
242 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
243 {
244 inode->i_mode = attr->mode & S_IFMT;
245 inode->i_size = attr->size;
246 if (S_ISREG(inode->i_mode)) {
247 fuse_init_common(inode);
248 fuse_init_file_inode(inode);
249 } else if (S_ISDIR(inode->i_mode))
250 fuse_init_dir(inode);
251 else if (S_ISLNK(inode->i_mode))
252 fuse_init_symlink(inode);
253 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
254 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
255 fuse_init_common(inode);
256 init_special_inode(inode, inode->i_mode,
257 new_decode_dev(attr->rdev));
258 } else
259 BUG();
260 }
261
262 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
263 {
264 u64 nodeid = *(u64 *) _nodeidp;
265 if (get_node_id(inode) == nodeid)
266 return 1;
267 else
268 return 0;
269 }
270
271 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
272 {
273 u64 nodeid = *(u64 *) _nodeidp;
274 get_fuse_inode(inode)->nodeid = nodeid;
275 return 0;
276 }
277
278 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
279 int generation, struct fuse_attr *attr,
280 u64 attr_valid, u64 attr_version)
281 {
282 struct inode *inode;
283 struct fuse_inode *fi;
284 struct fuse_conn *fc = get_fuse_conn_super(sb);
285
286 retry:
287 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
288 if (!inode)
289 return NULL;
290
291 if ((inode->i_state & I_NEW)) {
292 inode->i_flags |= S_NOATIME|S_NOCMTIME;
293 inode->i_generation = generation;
294 inode->i_data.backing_dev_info = &fc->bdi;
295 fuse_init_inode(inode, attr);
296 unlock_new_inode(inode);
297 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
298 /* Inode has changed type, any I/O on the old should fail */
299 make_bad_inode(inode);
300 iput(inode);
301 goto retry;
302 }
303
304 fi = get_fuse_inode(inode);
305 spin_lock(&fc->lock);
306 fi->nlookup++;
307 spin_unlock(&fc->lock);
308 fuse_change_attributes(inode, attr, attr_valid, attr_version);
309
310 return inode;
311 }
312
313 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
314 loff_t offset, loff_t len)
315 {
316 struct inode *inode;
317 pgoff_t pg_start;
318 pgoff_t pg_end;
319
320 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
321 if (!inode)
322 return -ENOENT;
323
324 fuse_invalidate_attr(inode);
325 if (offset >= 0) {
326 pg_start = offset >> PAGE_CACHE_SHIFT;
327 if (len <= 0)
328 pg_end = -1;
329 else
330 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
331 invalidate_inode_pages2_range(inode->i_mapping,
332 pg_start, pg_end);
333 }
334 iput(inode);
335 return 0;
336 }
337
338 static void fuse_umount_begin(struct super_block *sb)
339 {
340 fuse_abort_conn(get_fuse_conn_super(sb));
341 }
342
343 static void fuse_send_destroy(struct fuse_conn *fc)
344 {
345 struct fuse_req *req = fc->destroy_req;
346 if (req && fc->conn_init) {
347 fc->destroy_req = NULL;
348 req->in.h.opcode = FUSE_DESTROY;
349 req->force = 1;
350 req->background = 0;
351 fuse_request_send(fc, req);
352 fuse_put_request(fc, req);
353 }
354 }
355
356 static void fuse_bdi_destroy(struct fuse_conn *fc)
357 {
358 if (fc->bdi_initialized)
359 bdi_destroy(&fc->bdi);
360 }
361
362 void fuse_conn_kill(struct fuse_conn *fc)
363 {
364 spin_lock(&fc->lock);
365 fc->connected = 0;
366 fc->blocked = 0;
367 fc->initialized = 1;
368 spin_unlock(&fc->lock);
369 /* Flush all readers on this fs */
370 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
371 wake_up_all(&fc->waitq);
372 wake_up_all(&fc->blocked_waitq);
373 wake_up_all(&fc->reserved_req_waitq);
374 }
375 EXPORT_SYMBOL_GPL(fuse_conn_kill);
376
377 static void fuse_put_super(struct super_block *sb)
378 {
379 struct fuse_conn *fc = get_fuse_conn_super(sb);
380
381 fuse_send_destroy(fc);
382
383 fuse_conn_kill(fc);
384 mutex_lock(&fuse_mutex);
385 list_del(&fc->entry);
386 fuse_ctl_remove_conn(fc);
387 mutex_unlock(&fuse_mutex);
388 fuse_bdi_destroy(fc);
389
390 fuse_conn_put(fc);
391 }
392
393 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
394 {
395 stbuf->f_type = FUSE_SUPER_MAGIC;
396 stbuf->f_bsize = attr->bsize;
397 stbuf->f_frsize = attr->frsize;
398 stbuf->f_blocks = attr->blocks;
399 stbuf->f_bfree = attr->bfree;
400 stbuf->f_bavail = attr->bavail;
401 stbuf->f_files = attr->files;
402 stbuf->f_ffree = attr->ffree;
403 stbuf->f_namelen = attr->namelen;
404 /* fsid is left zero */
405 }
406
407 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
408 {
409 struct super_block *sb = dentry->d_sb;
410 struct fuse_conn *fc = get_fuse_conn_super(sb);
411 struct fuse_req *req;
412 struct fuse_statfs_out outarg;
413 int err;
414
415 if (!fuse_allow_current_process(fc)) {
416 buf->f_type = FUSE_SUPER_MAGIC;
417 return 0;
418 }
419
420 req = fuse_get_req_nopages(fc);
421 if (IS_ERR(req))
422 return PTR_ERR(req);
423
424 memset(&outarg, 0, sizeof(outarg));
425 req->in.numargs = 0;
426 req->in.h.opcode = FUSE_STATFS;
427 req->in.h.nodeid = get_node_id(dentry->d_inode);
428 req->out.numargs = 1;
429 req->out.args[0].size =
430 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
431 req->out.args[0].value = &outarg;
432 fuse_request_send(fc, req);
433 err = req->out.h.error;
434 if (!err)
435 convert_fuse_statfs(buf, &outarg.st);
436 fuse_put_request(fc, req);
437 return err;
438 }
439
440 enum {
441 OPT_FD,
442 OPT_ROOTMODE,
443 OPT_USER_ID,
444 OPT_GROUP_ID,
445 OPT_DEFAULT_PERMISSIONS,
446 OPT_ALLOW_OTHER,
447 OPT_MAX_READ,
448 OPT_BLKSIZE,
449 OPT_ERR
450 };
451
452 static const match_table_t tokens = {
453 {OPT_FD, "fd=%u"},
454 {OPT_ROOTMODE, "rootmode=%o"},
455 {OPT_USER_ID, "user_id=%u"},
456 {OPT_GROUP_ID, "group_id=%u"},
457 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
458 {OPT_ALLOW_OTHER, "allow_other"},
459 {OPT_MAX_READ, "max_read=%u"},
460 {OPT_BLKSIZE, "blksize=%u"},
461 {OPT_ERR, NULL}
462 };
463
464 static int fuse_match_uint(substring_t *s, unsigned int *res)
465 {
466 int err = -ENOMEM;
467 char *buf = match_strdup(s);
468 if (buf) {
469 err = kstrtouint(buf, 10, res);
470 kfree(buf);
471 }
472 return err;
473 }
474
475 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
476 {
477 char *p;
478 memset(d, 0, sizeof(struct fuse_mount_data));
479 d->max_read = ~0;
480 d->blksize = FUSE_DEFAULT_BLKSIZE;
481
482 while ((p = strsep(&opt, ",")) != NULL) {
483 int token;
484 int value;
485 unsigned uv;
486 substring_t args[MAX_OPT_ARGS];
487 if (!*p)
488 continue;
489
490 token = match_token(p, tokens, args);
491 switch (token) {
492 case OPT_FD:
493 if (match_int(&args[0], &value))
494 return 0;
495 d->fd = value;
496 d->fd_present = 1;
497 break;
498
499 case OPT_ROOTMODE:
500 if (match_octal(&args[0], &value))
501 return 0;
502 if (!fuse_valid_type(value))
503 return 0;
504 d->rootmode = value;
505 d->rootmode_present = 1;
506 break;
507
508 case OPT_USER_ID:
509 if (fuse_match_uint(&args[0], &uv))
510 return 0;
511 d->user_id = make_kuid(current_user_ns(), uv);
512 if (!uid_valid(d->user_id))
513 return 0;
514 d->user_id_present = 1;
515 break;
516
517 case OPT_GROUP_ID:
518 if (fuse_match_uint(&args[0], &uv))
519 return 0;
520 d->group_id = make_kgid(current_user_ns(), uv);
521 if (!gid_valid(d->group_id))
522 return 0;
523 d->group_id_present = 1;
524 break;
525
526 case OPT_DEFAULT_PERMISSIONS:
527 d->flags |= FUSE_DEFAULT_PERMISSIONS;
528 break;
529
530 case OPT_ALLOW_OTHER:
531 d->flags |= FUSE_ALLOW_OTHER;
532 break;
533
534 case OPT_MAX_READ:
535 if (match_int(&args[0], &value))
536 return 0;
537 d->max_read = value;
538 break;
539
540 case OPT_BLKSIZE:
541 if (!is_bdev || match_int(&args[0], &value))
542 return 0;
543 d->blksize = value;
544 break;
545
546 default:
547 return 0;
548 }
549 }
550
551 if (!d->fd_present || !d->rootmode_present ||
552 !d->user_id_present || !d->group_id_present)
553 return 0;
554
555 return 1;
556 }
557
558 static int fuse_show_options(struct seq_file *m, struct dentry *root)
559 {
560 struct super_block *sb = root->d_sb;
561 struct fuse_conn *fc = get_fuse_conn_super(sb);
562
563 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
564 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
565 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
566 seq_puts(m, ",default_permissions");
567 if (fc->flags & FUSE_ALLOW_OTHER)
568 seq_puts(m, ",allow_other");
569 if (fc->max_read != ~0)
570 seq_printf(m, ",max_read=%u", fc->max_read);
571 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
572 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
573 return 0;
574 }
575
576 void fuse_conn_init(struct fuse_conn *fc)
577 {
578 memset(fc, 0, sizeof(*fc));
579 spin_lock_init(&fc->lock);
580 mutex_init(&fc->inst_mutex);
581 init_rwsem(&fc->killsb);
582 atomic_set(&fc->count, 1);
583 init_waitqueue_head(&fc->waitq);
584 init_waitqueue_head(&fc->blocked_waitq);
585 init_waitqueue_head(&fc->reserved_req_waitq);
586 INIT_LIST_HEAD(&fc->pending);
587 INIT_LIST_HEAD(&fc->processing);
588 INIT_LIST_HEAD(&fc->io);
589 INIT_LIST_HEAD(&fc->interrupts);
590 INIT_LIST_HEAD(&fc->bg_queue);
591 INIT_LIST_HEAD(&fc->entry);
592 fc->forget_list_tail = &fc->forget_list_head;
593 atomic_set(&fc->num_waiting, 0);
594 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
595 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
596 fc->khctr = 0;
597 fc->polled_files = RB_ROOT;
598 fc->reqctr = 0;
599 fc->blocked = 0;
600 fc->initialized = 0;
601 fc->attr_version = 1;
602 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
603 }
604 EXPORT_SYMBOL_GPL(fuse_conn_init);
605
606 void fuse_conn_put(struct fuse_conn *fc)
607 {
608 if (atomic_dec_and_test(&fc->count)) {
609 if (fc->destroy_req)
610 fuse_request_free(fc->destroy_req);
611 mutex_destroy(&fc->inst_mutex);
612 fc->release(fc);
613 }
614 }
615 EXPORT_SYMBOL_GPL(fuse_conn_put);
616
617 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
618 {
619 atomic_inc(&fc->count);
620 return fc;
621 }
622 EXPORT_SYMBOL_GPL(fuse_conn_get);
623
624 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
625 {
626 struct fuse_attr attr;
627 memset(&attr, 0, sizeof(attr));
628
629 attr.mode = mode;
630 attr.ino = FUSE_ROOT_ID;
631 attr.nlink = 1;
632 return fuse_iget(sb, 1, 0, &attr, 0, 0);
633 }
634
635 struct fuse_inode_handle {
636 u64 nodeid;
637 u32 generation;
638 };
639
640 static struct dentry *fuse_get_dentry(struct super_block *sb,
641 struct fuse_inode_handle *handle)
642 {
643 struct fuse_conn *fc = get_fuse_conn_super(sb);
644 struct inode *inode;
645 struct dentry *entry;
646 int err = -ESTALE;
647
648 if (handle->nodeid == 0)
649 goto out_err;
650
651 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
652 if (!inode) {
653 struct fuse_entry_out outarg;
654 struct qstr name;
655
656 if (!fc->export_support)
657 goto out_err;
658
659 name.len = 1;
660 name.name = ".";
661 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
662 &inode);
663 if (err && err != -ENOENT)
664 goto out_err;
665 if (err || !inode) {
666 err = -ESTALE;
667 goto out_err;
668 }
669 err = -EIO;
670 if (get_node_id(inode) != handle->nodeid)
671 goto out_iput;
672 }
673 err = -ESTALE;
674 if (inode->i_generation != handle->generation)
675 goto out_iput;
676
677 entry = d_obtain_alias(inode);
678 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
679 fuse_invalidate_entry_cache(entry);
680
681 return entry;
682
683 out_iput:
684 iput(inode);
685 out_err:
686 return ERR_PTR(err);
687 }
688
689 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
690 struct inode *parent)
691 {
692 int len = parent ? 6 : 3;
693 u64 nodeid;
694 u32 generation;
695
696 if (*max_len < len) {
697 *max_len = len;
698 return FILEID_INVALID;
699 }
700
701 nodeid = get_fuse_inode(inode)->nodeid;
702 generation = inode->i_generation;
703
704 fh[0] = (u32)(nodeid >> 32);
705 fh[1] = (u32)(nodeid & 0xffffffff);
706 fh[2] = generation;
707
708 if (parent) {
709 nodeid = get_fuse_inode(parent)->nodeid;
710 generation = parent->i_generation;
711
712 fh[3] = (u32)(nodeid >> 32);
713 fh[4] = (u32)(nodeid & 0xffffffff);
714 fh[5] = generation;
715 }
716
717 *max_len = len;
718 return parent ? 0x82 : 0x81;
719 }
720
721 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
722 struct fid *fid, int fh_len, int fh_type)
723 {
724 struct fuse_inode_handle handle;
725
726 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
727 return NULL;
728
729 handle.nodeid = (u64) fid->raw[0] << 32;
730 handle.nodeid |= (u64) fid->raw[1];
731 handle.generation = fid->raw[2];
732 return fuse_get_dentry(sb, &handle);
733 }
734
735 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
736 struct fid *fid, int fh_len, int fh_type)
737 {
738 struct fuse_inode_handle parent;
739
740 if (fh_type != 0x82 || fh_len < 6)
741 return NULL;
742
743 parent.nodeid = (u64) fid->raw[3] << 32;
744 parent.nodeid |= (u64) fid->raw[4];
745 parent.generation = fid->raw[5];
746 return fuse_get_dentry(sb, &parent);
747 }
748
749 static struct dentry *fuse_get_parent(struct dentry *child)
750 {
751 struct inode *child_inode = child->d_inode;
752 struct fuse_conn *fc = get_fuse_conn(child_inode);
753 struct inode *inode;
754 struct dentry *parent;
755 struct fuse_entry_out outarg;
756 struct qstr name;
757 int err;
758
759 if (!fc->export_support)
760 return ERR_PTR(-ESTALE);
761
762 name.len = 2;
763 name.name = "..";
764 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
765 &name, &outarg, &inode);
766 if (err) {
767 if (err == -ENOENT)
768 return ERR_PTR(-ESTALE);
769 return ERR_PTR(err);
770 }
771
772 parent = d_obtain_alias(inode);
773 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
774 fuse_invalidate_entry_cache(parent);
775
776 return parent;
777 }
778
779 static const struct export_operations fuse_export_operations = {
780 .fh_to_dentry = fuse_fh_to_dentry,
781 .fh_to_parent = fuse_fh_to_parent,
782 .encode_fh = fuse_encode_fh,
783 .get_parent = fuse_get_parent,
784 };
785
786 static const struct super_operations fuse_super_operations = {
787 .alloc_inode = fuse_alloc_inode,
788 .destroy_inode = fuse_destroy_inode,
789 .evict_inode = fuse_evict_inode,
790 .drop_inode = generic_delete_inode,
791 .remount_fs = fuse_remount_fs,
792 .put_super = fuse_put_super,
793 .umount_begin = fuse_umount_begin,
794 .statfs = fuse_statfs,
795 .show_options = fuse_show_options,
796 };
797
798 static void sanitize_global_limit(unsigned *limit)
799 {
800 if (*limit == 0)
801 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
802 sizeof(struct fuse_req);
803
804 if (*limit >= 1 << 16)
805 *limit = (1 << 16) - 1;
806 }
807
808 static int set_global_limit(const char *val, struct kernel_param *kp)
809 {
810 int rv;
811
812 rv = param_set_uint(val, kp);
813 if (rv)
814 return rv;
815
816 sanitize_global_limit((unsigned *)kp->arg);
817
818 return 0;
819 }
820
821 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
822 {
823 int cap_sys_admin = capable(CAP_SYS_ADMIN);
824
825 if (arg->minor < 13)
826 return;
827
828 sanitize_global_limit(&max_user_bgreq);
829 sanitize_global_limit(&max_user_congthresh);
830
831 if (arg->max_background) {
832 fc->max_background = arg->max_background;
833
834 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
835 fc->max_background = max_user_bgreq;
836 }
837 if (arg->congestion_threshold) {
838 fc->congestion_threshold = arg->congestion_threshold;
839
840 if (!cap_sys_admin &&
841 fc->congestion_threshold > max_user_congthresh)
842 fc->congestion_threshold = max_user_congthresh;
843 }
844 }
845
846 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
847 {
848 struct fuse_init_out *arg = &req->misc.init_out;
849
850 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
851 fc->conn_error = 1;
852 else {
853 unsigned long ra_pages;
854
855 process_init_limits(fc, arg);
856
857 if (arg->minor >= 6) {
858 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
859 if (arg->flags & FUSE_ASYNC_READ)
860 fc->async_read = 1;
861 if (!(arg->flags & FUSE_POSIX_LOCKS))
862 fc->no_lock = 1;
863 if (arg->minor >= 17) {
864 if (!(arg->flags & FUSE_FLOCK_LOCKS))
865 fc->no_flock = 1;
866 } else {
867 if (!(arg->flags & FUSE_POSIX_LOCKS))
868 fc->no_flock = 1;
869 }
870 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
871 fc->atomic_o_trunc = 1;
872 if (arg->minor >= 9) {
873 /* LOOKUP has dependency on proto version */
874 if (arg->flags & FUSE_EXPORT_SUPPORT)
875 fc->export_support = 1;
876 }
877 if (arg->flags & FUSE_BIG_WRITES)
878 fc->big_writes = 1;
879 if (arg->flags & FUSE_DONT_MASK)
880 fc->dont_mask = 1;
881 if (arg->flags & FUSE_AUTO_INVAL_DATA)
882 fc->auto_inval_data = 1;
883 if (arg->flags & FUSE_DO_READDIRPLUS) {
884 fc->do_readdirplus = 1;
885 if (arg->flags & FUSE_READDIRPLUS_AUTO)
886 fc->readdirplus_auto = 1;
887 }
888 if (arg->flags & FUSE_ASYNC_DIO)
889 fc->async_dio = 1;
890 } else {
891 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
892 fc->no_lock = 1;
893 fc->no_flock = 1;
894 }
895
896 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
897 fc->minor = arg->minor;
898 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
899 fc->max_write = max_t(unsigned, 4096, fc->max_write);
900 fc->conn_init = 1;
901 }
902 fc->initialized = 1;
903 wake_up_all(&fc->blocked_waitq);
904 }
905
906 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
907 {
908 struct fuse_init_in *arg = &req->misc.init_in;
909
910 arg->major = FUSE_KERNEL_VERSION;
911 arg->minor = FUSE_KERNEL_MINOR_VERSION;
912 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
913 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
914 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
915 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
916 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
917 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
918 req->in.h.opcode = FUSE_INIT;
919 req->in.numargs = 1;
920 req->in.args[0].size = sizeof(*arg);
921 req->in.args[0].value = arg;
922 req->out.numargs = 1;
923 /* Variable length argument used for backward compatibility
924 with interface version < 7.5. Rest of init_out is zeroed
925 by do_get_request(), so a short reply is not a problem */
926 req->out.argvar = 1;
927 req->out.args[0].size = sizeof(struct fuse_init_out);
928 req->out.args[0].value = &req->misc.init_out;
929 req->end = process_init_reply;
930 fuse_request_send_background(fc, req);
931 }
932
933 static void fuse_free_conn(struct fuse_conn *fc)
934 {
935 kfree(fc);
936 }
937
938 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
939 {
940 int err;
941
942 fc->bdi.name = "fuse";
943 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
944 /* fuse does it's own writeback accounting */
945 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
946
947 err = bdi_init(&fc->bdi);
948 if (err)
949 return err;
950
951 fc->bdi_initialized = 1;
952
953 if (sb->s_bdev) {
954 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
955 MAJOR(fc->dev), MINOR(fc->dev));
956 } else {
957 err = bdi_register_dev(&fc->bdi, fc->dev);
958 }
959
960 if (err)
961 return err;
962
963 /*
964 * For a single fuse filesystem use max 1% of dirty +
965 * writeback threshold.
966 *
967 * This gives about 1M of write buffer for memory maps on a
968 * machine with 1G and 10% dirty_ratio, which should be more
969 * than enough.
970 *
971 * Privileged users can raise it by writing to
972 *
973 * /sys/class/bdi/<bdi>/max_ratio
974 */
975 bdi_set_max_ratio(&fc->bdi, 1);
976
977 return 0;
978 }
979
980 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
981 {
982 struct fuse_conn *fc;
983 struct inode *root;
984 struct fuse_mount_data d;
985 struct file *file;
986 struct dentry *root_dentry;
987 struct fuse_req *init_req;
988 int err;
989 int is_bdev = sb->s_bdev != NULL;
990
991 err = -EINVAL;
992 if (sb->s_flags & MS_MANDLOCK)
993 goto err;
994
995 sb->s_flags &= ~MS_NOSEC;
996
997 if (!parse_fuse_opt((char *) data, &d, is_bdev))
998 goto err;
999
1000 if (is_bdev) {
1001 #ifdef CONFIG_BLOCK
1002 err = -EINVAL;
1003 if (!sb_set_blocksize(sb, d.blksize))
1004 goto err;
1005 #endif
1006 } else {
1007 sb->s_blocksize = PAGE_CACHE_SIZE;
1008 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1009 }
1010 sb->s_magic = FUSE_SUPER_MAGIC;
1011 sb->s_op = &fuse_super_operations;
1012 sb->s_maxbytes = MAX_LFS_FILESIZE;
1013 sb->s_time_gran = 1;
1014 sb->s_export_op = &fuse_export_operations;
1015
1016 file = fget(d.fd);
1017 err = -EINVAL;
1018 if (!file)
1019 goto err;
1020
1021 if ((file->f_op != &fuse_dev_operations) ||
1022 (file->f_cred->user_ns != &init_user_ns))
1023 goto err_fput;
1024
1025 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1026 err = -ENOMEM;
1027 if (!fc)
1028 goto err_fput;
1029
1030 fuse_conn_init(fc);
1031
1032 fc->dev = sb->s_dev;
1033 fc->sb = sb;
1034 err = fuse_bdi_init(fc, sb);
1035 if (err)
1036 goto err_put_conn;
1037
1038 sb->s_bdi = &fc->bdi;
1039
1040 /* Handle umasking inside the fuse code */
1041 if (sb->s_flags & MS_POSIXACL)
1042 fc->dont_mask = 1;
1043 sb->s_flags |= MS_POSIXACL;
1044
1045 fc->release = fuse_free_conn;
1046 fc->flags = d.flags;
1047 fc->user_id = d.user_id;
1048 fc->group_id = d.group_id;
1049 fc->max_read = max_t(unsigned, 4096, d.max_read);
1050
1051 /* Used by get_root_inode() */
1052 sb->s_fs_info = fc;
1053
1054 err = -ENOMEM;
1055 root = fuse_get_root_inode(sb, d.rootmode);
1056 root_dentry = d_make_root(root);
1057 if (!root_dentry)
1058 goto err_put_conn;
1059 /* only now - we want root dentry with NULL ->d_op */
1060 sb->s_d_op = &fuse_dentry_operations;
1061
1062 init_req = fuse_request_alloc(0);
1063 if (!init_req)
1064 goto err_put_root;
1065 init_req->background = 1;
1066
1067 if (is_bdev) {
1068 fc->destroy_req = fuse_request_alloc(0);
1069 if (!fc->destroy_req)
1070 goto err_free_init_req;
1071 }
1072
1073 mutex_lock(&fuse_mutex);
1074 err = -EINVAL;
1075 if (file->private_data)
1076 goto err_unlock;
1077
1078 err = fuse_ctl_add_conn(fc);
1079 if (err)
1080 goto err_unlock;
1081
1082 list_add_tail(&fc->entry, &fuse_conn_list);
1083 sb->s_root = root_dentry;
1084 fc->connected = 1;
1085 file->private_data = fuse_conn_get(fc);
1086 mutex_unlock(&fuse_mutex);
1087 /*
1088 * atomic_dec_and_test() in fput() provides the necessary
1089 * memory barrier for file->private_data to be visible on all
1090 * CPUs after this
1091 */
1092 fput(file);
1093
1094 fuse_send_init(fc, init_req);
1095
1096 return 0;
1097
1098 err_unlock:
1099 mutex_unlock(&fuse_mutex);
1100 err_free_init_req:
1101 fuse_request_free(init_req);
1102 err_put_root:
1103 dput(root_dentry);
1104 err_put_conn:
1105 fuse_bdi_destroy(fc);
1106 fuse_conn_put(fc);
1107 err_fput:
1108 fput(file);
1109 err:
1110 return err;
1111 }
1112
1113 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1114 int flags, const char *dev_name,
1115 void *raw_data)
1116 {
1117 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1118 }
1119
1120 static void fuse_kill_sb_anon(struct super_block *sb)
1121 {
1122 struct fuse_conn *fc = get_fuse_conn_super(sb);
1123
1124 if (fc) {
1125 down_write(&fc->killsb);
1126 fc->sb = NULL;
1127 up_write(&fc->killsb);
1128 }
1129
1130 kill_anon_super(sb);
1131 }
1132
1133 static struct file_system_type fuse_fs_type = {
1134 .owner = THIS_MODULE,
1135 .name = "fuse",
1136 .fs_flags = FS_HAS_SUBTYPE,
1137 .mount = fuse_mount,
1138 .kill_sb = fuse_kill_sb_anon,
1139 };
1140 MODULE_ALIAS_FS("fuse");
1141
1142 #ifdef CONFIG_BLOCK
1143 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1144 int flags, const char *dev_name,
1145 void *raw_data)
1146 {
1147 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1148 }
1149
1150 static void fuse_kill_sb_blk(struct super_block *sb)
1151 {
1152 struct fuse_conn *fc = get_fuse_conn_super(sb);
1153
1154 if (fc) {
1155 down_write(&fc->killsb);
1156 fc->sb = NULL;
1157 up_write(&fc->killsb);
1158 }
1159
1160 kill_block_super(sb);
1161 }
1162
1163 static struct file_system_type fuseblk_fs_type = {
1164 .owner = THIS_MODULE,
1165 .name = "fuseblk",
1166 .mount = fuse_mount_blk,
1167 .kill_sb = fuse_kill_sb_blk,
1168 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1169 };
1170 MODULE_ALIAS_FS("fuseblk");
1171
1172 static inline int register_fuseblk(void)
1173 {
1174 return register_filesystem(&fuseblk_fs_type);
1175 }
1176
1177 static inline void unregister_fuseblk(void)
1178 {
1179 unregister_filesystem(&fuseblk_fs_type);
1180 }
1181 #else
1182 static inline int register_fuseblk(void)
1183 {
1184 return 0;
1185 }
1186
1187 static inline void unregister_fuseblk(void)
1188 {
1189 }
1190 #endif
1191
1192 static void fuse_inode_init_once(void *foo)
1193 {
1194 struct inode *inode = foo;
1195
1196 inode_init_once(inode);
1197 }
1198
1199 static int __init fuse_fs_init(void)
1200 {
1201 int err;
1202
1203 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1204 sizeof(struct fuse_inode),
1205 0, SLAB_HWCACHE_ALIGN,
1206 fuse_inode_init_once);
1207 err = -ENOMEM;
1208 if (!fuse_inode_cachep)
1209 goto out;
1210
1211 err = register_fuseblk();
1212 if (err)
1213 goto out2;
1214
1215 err = register_filesystem(&fuse_fs_type);
1216 if (err)
1217 goto out3;
1218
1219 return 0;
1220
1221 out3:
1222 unregister_fuseblk();
1223 out2:
1224 kmem_cache_destroy(fuse_inode_cachep);
1225 out:
1226 return err;
1227 }
1228
1229 static void fuse_fs_cleanup(void)
1230 {
1231 unregister_filesystem(&fuse_fs_type);
1232 unregister_fuseblk();
1233
1234 /*
1235 * Make sure all delayed rcu free inodes are flushed before we
1236 * destroy cache.
1237 */
1238 rcu_barrier();
1239 kmem_cache_destroy(fuse_inode_cachep);
1240 }
1241
1242 static struct kobject *fuse_kobj;
1243 static struct kobject *connections_kobj;
1244
1245 static int fuse_sysfs_init(void)
1246 {
1247 int err;
1248
1249 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1250 if (!fuse_kobj) {
1251 err = -ENOMEM;
1252 goto out_err;
1253 }
1254
1255 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1256 if (!connections_kobj) {
1257 err = -ENOMEM;
1258 goto out_fuse_unregister;
1259 }
1260
1261 return 0;
1262
1263 out_fuse_unregister:
1264 kobject_put(fuse_kobj);
1265 out_err:
1266 return err;
1267 }
1268
1269 static void fuse_sysfs_cleanup(void)
1270 {
1271 kobject_put(connections_kobj);
1272 kobject_put(fuse_kobj);
1273 }
1274
1275 static int __init fuse_init(void)
1276 {
1277 int res;
1278
1279 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1280 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1281
1282 INIT_LIST_HEAD(&fuse_conn_list);
1283 res = fuse_fs_init();
1284 if (res)
1285 goto err;
1286
1287 res = fuse_dev_init();
1288 if (res)
1289 goto err_fs_cleanup;
1290
1291 res = fuse_sysfs_init();
1292 if (res)
1293 goto err_dev_cleanup;
1294
1295 res = fuse_ctl_init();
1296 if (res)
1297 goto err_sysfs_cleanup;
1298
1299 sanitize_global_limit(&max_user_bgreq);
1300 sanitize_global_limit(&max_user_congthresh);
1301
1302 return 0;
1303
1304 err_sysfs_cleanup:
1305 fuse_sysfs_cleanup();
1306 err_dev_cleanup:
1307 fuse_dev_cleanup();
1308 err_fs_cleanup:
1309 fuse_fs_cleanup();
1310 err:
1311 return res;
1312 }
1313
1314 static void __exit fuse_exit(void)
1315 {
1316 printk(KERN_DEBUG "fuse exit\n");
1317
1318 fuse_ctl_cleanup();
1319 fuse_sysfs_cleanup();
1320 fuse_fs_cleanup();
1321 fuse_dev_cleanup();
1322 }
1323
1324 module_init(fuse_init);
1325 module_exit(fuse_exit);
Linux with added FPC-III support