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