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
fuse_alloc_forget(void)74 struct fuse_forget_link *fuse_alloc_forget(void)
75 {
76 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
77 }
78
fuse_alloc_inode(struct super_block * sb)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
fuse_i_callback(struct rcu_head * head)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
fuse_destroy_inode(struct inode * inode)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
fuse_evict_inode(struct inode * inode)123 static void fuse_evict_inode(struct inode *inode)
124 {
125 truncate_inode_pages(&inode->i_data, 0);
126 end_writeback(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
fuse_remount_fs(struct super_block * sb,int * flags,char * data)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 */
fuse_squash_ino(u64 ino64)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
fuse_change_attributes_common(struct inode * inode,struct fuse_attr * attr,u64 attr_valid)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
fuse_change_attributes(struct inode * inode,struct fuse_attr * attr,u64 attr_valid,u64 attr_version)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
201 spin_lock(&fc->lock);
202 if (attr_version != 0 && fi->attr_version > attr_version) {
203 spin_unlock(&fc->lock);
204 return;
205 }
206
207 fuse_change_attributes_common(inode, attr, attr_valid);
208
209 oldsize = inode->i_size;
210 i_size_write(inode, attr->size);
211 spin_unlock(&fc->lock);
212
213 if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
214 truncate_pagecache(inode, oldsize, attr->size);
215 invalidate_inode_pages2(inode->i_mapping);
216 }
217 }
218
fuse_init_inode(struct inode * inode,struct fuse_attr * attr)219 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
220 {
221 inode->i_mode = attr->mode & S_IFMT;
222 inode->i_size = attr->size;
223 if (S_ISREG(inode->i_mode)) {
224 fuse_init_common(inode);
225 fuse_init_file_inode(inode);
226 } else if (S_ISDIR(inode->i_mode))
227 fuse_init_dir(inode);
228 else if (S_ISLNK(inode->i_mode))
229 fuse_init_symlink(inode);
230 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
231 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
232 fuse_init_common(inode);
233 init_special_inode(inode, inode->i_mode,
234 new_decode_dev(attr->rdev));
235 } else
236 BUG();
237 }
238
fuse_inode_eq(struct inode * inode,void * _nodeidp)239 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
240 {
241 u64 nodeid = *(u64 *) _nodeidp;
242 if (get_node_id(inode) == nodeid)
243 return 1;
244 else
245 return 0;
246 }
247
fuse_inode_set(struct inode * inode,void * _nodeidp)248 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
249 {
250 u64 nodeid = *(u64 *) _nodeidp;
251 get_fuse_inode(inode)->nodeid = nodeid;
252 return 0;
253 }
254
fuse_iget(struct super_block * sb,u64 nodeid,int generation,struct fuse_attr * attr,u64 attr_valid,u64 attr_version)255 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
256 int generation, struct fuse_attr *attr,
257 u64 attr_valid, u64 attr_version)
258 {
259 struct inode *inode;
260 struct fuse_inode *fi;
261 struct fuse_conn *fc = get_fuse_conn_super(sb);
262
263 retry:
264 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
265 if (!inode)
266 return NULL;
267
268 if ((inode->i_state & I_NEW)) {
269 inode->i_flags |= S_NOATIME|S_NOCMTIME;
270 inode->i_generation = generation;
271 inode->i_data.backing_dev_info = &fc->bdi;
272 fuse_init_inode(inode, attr);
273 unlock_new_inode(inode);
274 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
275 /* Inode has changed type, any I/O on the old should fail */
276 make_bad_inode(inode);
277 iput(inode);
278 goto retry;
279 }
280
281 fi = get_fuse_inode(inode);
282 spin_lock(&fc->lock);
283 fi->nlookup++;
284 spin_unlock(&fc->lock);
285 fuse_change_attributes(inode, attr, attr_valid, attr_version);
286
287 return inode;
288 }
289
fuse_reverse_inval_inode(struct super_block * sb,u64 nodeid,loff_t offset,loff_t len)290 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
291 loff_t offset, loff_t len)
292 {
293 struct inode *inode;
294 pgoff_t pg_start;
295 pgoff_t pg_end;
296
297 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
298 if (!inode)
299 return -ENOENT;
300
301 fuse_invalidate_attr(inode);
302 if (offset >= 0) {
303 pg_start = offset >> PAGE_CACHE_SHIFT;
304 if (len <= 0)
305 pg_end = -1;
306 else
307 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
308 invalidate_inode_pages2_range(inode->i_mapping,
309 pg_start, pg_end);
310 }
311 iput(inode);
312 return 0;
313 }
314
fuse_umount_begin(struct super_block * sb)315 static void fuse_umount_begin(struct super_block *sb)
316 {
317 fuse_abort_conn(get_fuse_conn_super(sb));
318 }
319
fuse_send_destroy(struct fuse_conn * fc)320 static void fuse_send_destroy(struct fuse_conn *fc)
321 {
322 struct fuse_req *req = fc->destroy_req;
323 if (req && fc->conn_init) {
324 fc->destroy_req = NULL;
325 req->in.h.opcode = FUSE_DESTROY;
326 req->force = 1;
327 fuse_request_send(fc, req);
328 fuse_put_request(fc, req);
329 }
330 }
331
fuse_bdi_destroy(struct fuse_conn * fc)332 static void fuse_bdi_destroy(struct fuse_conn *fc)
333 {
334 if (fc->bdi_initialized)
335 bdi_destroy(&fc->bdi);
336 }
337
fuse_conn_kill(struct fuse_conn * fc)338 void fuse_conn_kill(struct fuse_conn *fc)
339 {
340 spin_lock(&fc->lock);
341 fc->connected = 0;
342 fc->blocked = 0;
343 spin_unlock(&fc->lock);
344 /* Flush all readers on this fs */
345 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
346 wake_up_all(&fc->waitq);
347 wake_up_all(&fc->blocked_waitq);
348 wake_up_all(&fc->reserved_req_waitq);
349 mutex_lock(&fuse_mutex);
350 list_del(&fc->entry);
351 fuse_ctl_remove_conn(fc);
352 mutex_unlock(&fuse_mutex);
353 fuse_bdi_destroy(fc);
354 }
355 EXPORT_SYMBOL_GPL(fuse_conn_kill);
356
fuse_put_super(struct super_block * sb)357 static void fuse_put_super(struct super_block *sb)
358 {
359 struct fuse_conn *fc = get_fuse_conn_super(sb);
360
361 fuse_send_destroy(fc);
362 fuse_conn_kill(fc);
363 fuse_conn_put(fc);
364 }
365
convert_fuse_statfs(struct kstatfs * stbuf,struct fuse_kstatfs * attr)366 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
367 {
368 stbuf->f_type = FUSE_SUPER_MAGIC;
369 stbuf->f_bsize = attr->bsize;
370 stbuf->f_frsize = attr->frsize;
371 stbuf->f_blocks = attr->blocks;
372 stbuf->f_bfree = attr->bfree;
373 stbuf->f_bavail = attr->bavail;
374 stbuf->f_files = attr->files;
375 stbuf->f_ffree = attr->ffree;
376 stbuf->f_namelen = attr->namelen;
377 /* fsid is left zero */
378 }
379
fuse_statfs(struct dentry * dentry,struct kstatfs * buf)380 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
381 {
382 struct super_block *sb = dentry->d_sb;
383 struct fuse_conn *fc = get_fuse_conn_super(sb);
384 struct fuse_req *req;
385 struct fuse_statfs_out outarg;
386 int err;
387
388 if (!fuse_allow_task(fc, current)) {
389 buf->f_type = FUSE_SUPER_MAGIC;
390 return 0;
391 }
392
393 req = fuse_get_req(fc);
394 if (IS_ERR(req))
395 return PTR_ERR(req);
396
397 memset(&outarg, 0, sizeof(outarg));
398 req->in.numargs = 0;
399 req->in.h.opcode = FUSE_STATFS;
400 req->in.h.nodeid = get_node_id(dentry->d_inode);
401 req->out.numargs = 1;
402 req->out.args[0].size =
403 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
404 req->out.args[0].value = &outarg;
405 fuse_request_send(fc, req);
406 err = req->out.h.error;
407 if (!err)
408 convert_fuse_statfs(buf, &outarg.st);
409 fuse_put_request(fc, req);
410 return err;
411 }
412
413 enum {
414 OPT_FD,
415 OPT_ROOTMODE,
416 OPT_USER_ID,
417 OPT_GROUP_ID,
418 OPT_DEFAULT_PERMISSIONS,
419 OPT_ALLOW_OTHER,
420 OPT_MAX_READ,
421 OPT_BLKSIZE,
422 OPT_ERR
423 };
424
425 static const match_table_t tokens = {
426 {OPT_FD, "fd=%u"},
427 {OPT_ROOTMODE, "rootmode=%o"},
428 {OPT_USER_ID, "user_id=%u"},
429 {OPT_GROUP_ID, "group_id=%u"},
430 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
431 {OPT_ALLOW_OTHER, "allow_other"},
432 {OPT_MAX_READ, "max_read=%u"},
433 {OPT_BLKSIZE, "blksize=%u"},
434 {OPT_ERR, NULL}
435 };
436
parse_fuse_opt(char * opt,struct fuse_mount_data * d,int is_bdev)437 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
438 {
439 char *p;
440 memset(d, 0, sizeof(struct fuse_mount_data));
441 d->max_read = ~0;
442 d->blksize = FUSE_DEFAULT_BLKSIZE;
443
444 while ((p = strsep(&opt, ",")) != NULL) {
445 int token;
446 int value;
447 substring_t args[MAX_OPT_ARGS];
448 if (!*p)
449 continue;
450
451 token = match_token(p, tokens, args);
452 switch (token) {
453 case OPT_FD:
454 if (match_int(&args[0], &value))
455 return 0;
456 d->fd = value;
457 d->fd_present = 1;
458 break;
459
460 case OPT_ROOTMODE:
461 if (match_octal(&args[0], &value))
462 return 0;
463 if (!fuse_valid_type(value))
464 return 0;
465 d->rootmode = value;
466 d->rootmode_present = 1;
467 break;
468
469 case OPT_USER_ID:
470 if (match_int(&args[0], &value))
471 return 0;
472 d->user_id = value;
473 d->user_id_present = 1;
474 break;
475
476 case OPT_GROUP_ID:
477 if (match_int(&args[0], &value))
478 return 0;
479 d->group_id = value;
480 d->group_id_present = 1;
481 break;
482
483 case OPT_DEFAULT_PERMISSIONS:
484 d->flags |= FUSE_DEFAULT_PERMISSIONS;
485 break;
486
487 case OPT_ALLOW_OTHER:
488 d->flags |= FUSE_ALLOW_OTHER;
489 break;
490
491 case OPT_MAX_READ:
492 if (match_int(&args[0], &value))
493 return 0;
494 d->max_read = value;
495 break;
496
497 case OPT_BLKSIZE:
498 if (!is_bdev || match_int(&args[0], &value))
499 return 0;
500 d->blksize = value;
501 break;
502
503 default:
504 return 0;
505 }
506 }
507
508 if (!d->fd_present || !d->rootmode_present ||
509 !d->user_id_present || !d->group_id_present)
510 return 0;
511
512 return 1;
513 }
514
fuse_show_options(struct seq_file * m,struct dentry * root)515 static int fuse_show_options(struct seq_file *m, struct dentry *root)
516 {
517 struct super_block *sb = root->d_sb;
518 struct fuse_conn *fc = get_fuse_conn_super(sb);
519
520 seq_printf(m, ",user_id=%u", fc->user_id);
521 seq_printf(m, ",group_id=%u", fc->group_id);
522 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
523 seq_puts(m, ",default_permissions");
524 if (fc->flags & FUSE_ALLOW_OTHER)
525 seq_puts(m, ",allow_other");
526 if (fc->max_read != ~0)
527 seq_printf(m, ",max_read=%u", fc->max_read);
528 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
529 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
530 return 0;
531 }
532
fuse_conn_init(struct fuse_conn * fc)533 void fuse_conn_init(struct fuse_conn *fc)
534 {
535 memset(fc, 0, sizeof(*fc));
536 spin_lock_init(&fc->lock);
537 mutex_init(&fc->inst_mutex);
538 init_rwsem(&fc->killsb);
539 atomic_set(&fc->count, 1);
540 init_waitqueue_head(&fc->waitq);
541 init_waitqueue_head(&fc->blocked_waitq);
542 init_waitqueue_head(&fc->reserved_req_waitq);
543 INIT_LIST_HEAD(&fc->pending);
544 INIT_LIST_HEAD(&fc->processing);
545 INIT_LIST_HEAD(&fc->io);
546 INIT_LIST_HEAD(&fc->interrupts);
547 INIT_LIST_HEAD(&fc->bg_queue);
548 INIT_LIST_HEAD(&fc->entry);
549 fc->forget_list_tail = &fc->forget_list_head;
550 atomic_set(&fc->num_waiting, 0);
551 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
552 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
553 fc->khctr = 0;
554 fc->polled_files = RB_ROOT;
555 fc->reqctr = 0;
556 fc->blocked = 1;
557 fc->attr_version = 1;
558 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
559 }
560 EXPORT_SYMBOL_GPL(fuse_conn_init);
561
fuse_conn_put(struct fuse_conn * fc)562 void fuse_conn_put(struct fuse_conn *fc)
563 {
564 if (atomic_dec_and_test(&fc->count)) {
565 if (fc->destroy_req)
566 fuse_request_free(fc->destroy_req);
567 mutex_destroy(&fc->inst_mutex);
568 fc->release(fc);
569 }
570 }
571 EXPORT_SYMBOL_GPL(fuse_conn_put);
572
fuse_conn_get(struct fuse_conn * fc)573 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
574 {
575 atomic_inc(&fc->count);
576 return fc;
577 }
578 EXPORT_SYMBOL_GPL(fuse_conn_get);
579
fuse_get_root_inode(struct super_block * sb,unsigned mode)580 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
581 {
582 struct fuse_attr attr;
583 memset(&attr, 0, sizeof(attr));
584
585 attr.mode = mode;
586 attr.ino = FUSE_ROOT_ID;
587 attr.nlink = 1;
588 return fuse_iget(sb, 1, 0, &attr, 0, 0);
589 }
590
591 struct fuse_inode_handle {
592 u64 nodeid;
593 u32 generation;
594 };
595
fuse_get_dentry(struct super_block * sb,struct fuse_inode_handle * handle)596 static struct dentry *fuse_get_dentry(struct super_block *sb,
597 struct fuse_inode_handle *handle)
598 {
599 struct fuse_conn *fc = get_fuse_conn_super(sb);
600 struct inode *inode;
601 struct dentry *entry;
602 int err = -ESTALE;
603
604 if (handle->nodeid == 0)
605 goto out_err;
606
607 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
608 if (!inode) {
609 struct fuse_entry_out outarg;
610 struct qstr name;
611
612 if (!fc->export_support)
613 goto out_err;
614
615 name.len = 1;
616 name.name = ".";
617 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
618 &inode);
619 if (err && err != -ENOENT)
620 goto out_err;
621 if (err || !inode) {
622 err = -ESTALE;
623 goto out_err;
624 }
625 err = -EIO;
626 if (get_node_id(inode) != handle->nodeid)
627 goto out_iput;
628 }
629 err = -ESTALE;
630 if (inode->i_generation != handle->generation)
631 goto out_iput;
632
633 entry = d_obtain_alias(inode);
634 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
635 fuse_invalidate_entry_cache(entry);
636
637 return entry;
638
639 out_iput:
640 iput(inode);
641 out_err:
642 return ERR_PTR(err);
643 }
644
fuse_encode_fh(struct dentry * dentry,u32 * fh,int * max_len,int connectable)645 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
646 int connectable)
647 {
648 struct inode *inode = dentry->d_inode;
649 bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
650 int len = encode_parent ? 6 : 3;
651 u64 nodeid;
652 u32 generation;
653
654 if (*max_len < len) {
655 *max_len = len;
656 return 255;
657 }
658
659 nodeid = get_fuse_inode(inode)->nodeid;
660 generation = inode->i_generation;
661
662 fh[0] = (u32)(nodeid >> 32);
663 fh[1] = (u32)(nodeid & 0xffffffff);
664 fh[2] = generation;
665
666 if (encode_parent) {
667 struct inode *parent;
668
669 spin_lock(&dentry->d_lock);
670 parent = dentry->d_parent->d_inode;
671 nodeid = get_fuse_inode(parent)->nodeid;
672 generation = parent->i_generation;
673 spin_unlock(&dentry->d_lock);
674
675 fh[3] = (u32)(nodeid >> 32);
676 fh[4] = (u32)(nodeid & 0xffffffff);
677 fh[5] = generation;
678 }
679
680 *max_len = len;
681 return encode_parent ? 0x82 : 0x81;
682 }
683
fuse_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)684 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
685 struct fid *fid, int fh_len, int fh_type)
686 {
687 struct fuse_inode_handle handle;
688
689 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
690 return NULL;
691
692 handle.nodeid = (u64) fid->raw[0] << 32;
693 handle.nodeid |= (u64) fid->raw[1];
694 handle.generation = fid->raw[2];
695 return fuse_get_dentry(sb, &handle);
696 }
697
fuse_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)698 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
699 struct fid *fid, int fh_len, int fh_type)
700 {
701 struct fuse_inode_handle parent;
702
703 if (fh_type != 0x82 || fh_len < 6)
704 return NULL;
705
706 parent.nodeid = (u64) fid->raw[3] << 32;
707 parent.nodeid |= (u64) fid->raw[4];
708 parent.generation = fid->raw[5];
709 return fuse_get_dentry(sb, &parent);
710 }
711
fuse_get_parent(struct dentry * child)712 static struct dentry *fuse_get_parent(struct dentry *child)
713 {
714 struct inode *child_inode = child->d_inode;
715 struct fuse_conn *fc = get_fuse_conn(child_inode);
716 struct inode *inode;
717 struct dentry *parent;
718 struct fuse_entry_out outarg;
719 struct qstr name;
720 int err;
721
722 if (!fc->export_support)
723 return ERR_PTR(-ESTALE);
724
725 name.len = 2;
726 name.name = "..";
727 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
728 &name, &outarg, &inode);
729 if (err) {
730 if (err == -ENOENT)
731 return ERR_PTR(-ESTALE);
732 return ERR_PTR(err);
733 }
734
735 parent = d_obtain_alias(inode);
736 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
737 fuse_invalidate_entry_cache(parent);
738
739 return parent;
740 }
741
742 static const struct export_operations fuse_export_operations = {
743 .fh_to_dentry = fuse_fh_to_dentry,
744 .fh_to_parent = fuse_fh_to_parent,
745 .encode_fh = fuse_encode_fh,
746 .get_parent = fuse_get_parent,
747 };
748
749 static const struct super_operations fuse_super_operations = {
750 .alloc_inode = fuse_alloc_inode,
751 .destroy_inode = fuse_destroy_inode,
752 .evict_inode = fuse_evict_inode,
753 .drop_inode = generic_delete_inode,
754 .remount_fs = fuse_remount_fs,
755 .put_super = fuse_put_super,
756 .umount_begin = fuse_umount_begin,
757 .statfs = fuse_statfs,
758 .show_options = fuse_show_options,
759 };
760
sanitize_global_limit(unsigned * limit)761 static void sanitize_global_limit(unsigned *limit)
762 {
763 if (*limit == 0)
764 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
765 sizeof(struct fuse_req);
766
767 if (*limit >= 1 << 16)
768 *limit = (1 << 16) - 1;
769 }
770
set_global_limit(const char * val,struct kernel_param * kp)771 static int set_global_limit(const char *val, struct kernel_param *kp)
772 {
773 int rv;
774
775 rv = param_set_uint(val, kp);
776 if (rv)
777 return rv;
778
779 sanitize_global_limit((unsigned *)kp->arg);
780
781 return 0;
782 }
783
process_init_limits(struct fuse_conn * fc,struct fuse_init_out * arg)784 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
785 {
786 int cap_sys_admin = capable(CAP_SYS_ADMIN);
787
788 if (arg->minor < 13)
789 return;
790
791 sanitize_global_limit(&max_user_bgreq);
792 sanitize_global_limit(&max_user_congthresh);
793
794 if (arg->max_background) {
795 fc->max_background = arg->max_background;
796
797 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
798 fc->max_background = max_user_bgreq;
799 }
800 if (arg->congestion_threshold) {
801 fc->congestion_threshold = arg->congestion_threshold;
802
803 if (!cap_sys_admin &&
804 fc->congestion_threshold > max_user_congthresh)
805 fc->congestion_threshold = max_user_congthresh;
806 }
807 }
808
process_init_reply(struct fuse_conn * fc,struct fuse_req * req)809 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
810 {
811 struct fuse_init_out *arg = &req->misc.init_out;
812
813 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
814 fc->conn_error = 1;
815 else {
816 unsigned long ra_pages;
817
818 process_init_limits(fc, arg);
819
820 if (arg->minor >= 6) {
821 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
822 if (arg->flags & FUSE_ASYNC_READ)
823 fc->async_read = 1;
824 if (!(arg->flags & FUSE_POSIX_LOCKS))
825 fc->no_lock = 1;
826 if (arg->minor >= 17) {
827 if (!(arg->flags & FUSE_FLOCK_LOCKS))
828 fc->no_flock = 1;
829 } else {
830 if (!(arg->flags & FUSE_POSIX_LOCKS))
831 fc->no_flock = 1;
832 }
833 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
834 fc->atomic_o_trunc = 1;
835 if (arg->minor >= 9) {
836 /* LOOKUP has dependency on proto version */
837 if (arg->flags & FUSE_EXPORT_SUPPORT)
838 fc->export_support = 1;
839 }
840 if (arg->flags & FUSE_BIG_WRITES)
841 fc->big_writes = 1;
842 if (arg->flags & FUSE_DONT_MASK)
843 fc->dont_mask = 1;
844 } else {
845 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
846 fc->no_lock = 1;
847 fc->no_flock = 1;
848 }
849
850 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
851 fc->minor = arg->minor;
852 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
853 fc->max_write = max_t(unsigned, 4096, fc->max_write);
854 fc->conn_init = 1;
855 }
856 fc->blocked = 0;
857 wake_up_all(&fc->blocked_waitq);
858 }
859
fuse_send_init(struct fuse_conn * fc,struct fuse_req * req)860 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
861 {
862 struct fuse_init_in *arg = &req->misc.init_in;
863
864 arg->major = FUSE_KERNEL_VERSION;
865 arg->minor = FUSE_KERNEL_MINOR_VERSION;
866 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
867 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
868 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
869 FUSE_FLOCK_LOCKS;
870 req->in.h.opcode = FUSE_INIT;
871 req->in.numargs = 1;
872 req->in.args[0].size = sizeof(*arg);
873 req->in.args[0].value = arg;
874 req->out.numargs = 1;
875 /* Variable length argument used for backward compatibility
876 with interface version < 7.5. Rest of init_out is zeroed
877 by do_get_request(), so a short reply is not a problem */
878 req->out.argvar = 1;
879 req->out.args[0].size = sizeof(struct fuse_init_out);
880 req->out.args[0].value = &req->misc.init_out;
881 req->end = process_init_reply;
882 fuse_request_send_background(fc, req);
883 }
884
fuse_free_conn(struct fuse_conn * fc)885 static void fuse_free_conn(struct fuse_conn *fc)
886 {
887 kfree(fc);
888 }
889
fuse_bdi_init(struct fuse_conn * fc,struct super_block * sb)890 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
891 {
892 int err;
893
894 fc->bdi.name = "fuse";
895 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
896 /* fuse does it's own writeback accounting */
897 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
898
899 err = bdi_init(&fc->bdi);
900 if (err)
901 return err;
902
903 fc->bdi_initialized = 1;
904
905 if (sb->s_bdev) {
906 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
907 MAJOR(fc->dev), MINOR(fc->dev));
908 } else {
909 err = bdi_register_dev(&fc->bdi, fc->dev);
910 }
911
912 if (err)
913 return err;
914
915 /*
916 * For a single fuse filesystem use max 1% of dirty +
917 * writeback threshold.
918 *
919 * This gives about 1M of write buffer for memory maps on a
920 * machine with 1G and 10% dirty_ratio, which should be more
921 * than enough.
922 *
923 * Privileged users can raise it by writing to
924 *
925 * /sys/class/bdi/<bdi>/max_ratio
926 */
927 bdi_set_max_ratio(&fc->bdi, 1);
928
929 return 0;
930 }
931
fuse_fill_super(struct super_block * sb,void * data,int silent)932 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
933 {
934 struct fuse_conn *fc;
935 struct inode *root;
936 struct fuse_mount_data d;
937 struct file *file;
938 struct dentry *root_dentry;
939 struct fuse_req *init_req;
940 int err;
941 int is_bdev = sb->s_bdev != NULL;
942
943 err = -EINVAL;
944 if (sb->s_flags & MS_MANDLOCK)
945 goto err;
946
947 sb->s_flags &= ~MS_NOSEC;
948
949 if (!parse_fuse_opt((char *) data, &d, is_bdev))
950 goto err;
951
952 if (is_bdev) {
953 #ifdef CONFIG_BLOCK
954 err = -EINVAL;
955 if (!sb_set_blocksize(sb, d.blksize))
956 goto err;
957 #endif
958 } else {
959 sb->s_blocksize = PAGE_CACHE_SIZE;
960 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
961 }
962 sb->s_magic = FUSE_SUPER_MAGIC;
963 sb->s_op = &fuse_super_operations;
964 sb->s_maxbytes = MAX_LFS_FILESIZE;
965 sb->s_time_gran = 1;
966 sb->s_export_op = &fuse_export_operations;
967
968 file = fget(d.fd);
969 err = -EINVAL;
970 if (!file)
971 goto err;
972
973 if (file->f_op != &fuse_dev_operations)
974 goto err_fput;
975
976 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
977 err = -ENOMEM;
978 if (!fc)
979 goto err_fput;
980
981 fuse_conn_init(fc);
982
983 fc->dev = sb->s_dev;
984 fc->sb = sb;
985 err = fuse_bdi_init(fc, sb);
986 if (err)
987 goto err_put_conn;
988
989 sb->s_bdi = &fc->bdi;
990
991 /* Handle umasking inside the fuse code */
992 if (sb->s_flags & MS_POSIXACL)
993 fc->dont_mask = 1;
994 sb->s_flags |= MS_POSIXACL;
995
996 fc->release = fuse_free_conn;
997 fc->flags = d.flags;
998 fc->user_id = d.user_id;
999 fc->group_id = d.group_id;
1000 fc->max_read = max_t(unsigned, 4096, d.max_read);
1001
1002 /* Used by get_root_inode() */
1003 sb->s_fs_info = fc;
1004
1005 err = -ENOMEM;
1006 root = fuse_get_root_inode(sb, d.rootmode);
1007 root_dentry = d_make_root(root);
1008 if (!root_dentry)
1009 goto err_put_conn;
1010 /* only now - we want root dentry with NULL ->d_op */
1011 sb->s_d_op = &fuse_dentry_operations;
1012
1013 init_req = fuse_request_alloc();
1014 if (!init_req)
1015 goto err_put_root;
1016
1017 if (is_bdev) {
1018 fc->destroy_req = fuse_request_alloc();
1019 if (!fc->destroy_req)
1020 goto err_free_init_req;
1021 }
1022
1023 mutex_lock(&fuse_mutex);
1024 err = -EINVAL;
1025 if (file->private_data)
1026 goto err_unlock;
1027
1028 err = fuse_ctl_add_conn(fc);
1029 if (err)
1030 goto err_unlock;
1031
1032 list_add_tail(&fc->entry, &fuse_conn_list);
1033 sb->s_root = root_dentry;
1034 fc->connected = 1;
1035 file->private_data = fuse_conn_get(fc);
1036 mutex_unlock(&fuse_mutex);
1037 /*
1038 * atomic_dec_and_test() in fput() provides the necessary
1039 * memory barrier for file->private_data to be visible on all
1040 * CPUs after this
1041 */
1042 fput(file);
1043
1044 fuse_send_init(fc, init_req);
1045
1046 return 0;
1047
1048 err_unlock:
1049 mutex_unlock(&fuse_mutex);
1050 err_free_init_req:
1051 fuse_request_free(init_req);
1052 err_put_root:
1053 dput(root_dentry);
1054 err_put_conn:
1055 fuse_bdi_destroy(fc);
1056 fuse_conn_put(fc);
1057 err_fput:
1058 fput(file);
1059 err:
1060 return err;
1061 }
1062
fuse_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data)1063 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1064 int flags, const char *dev_name,
1065 void *raw_data)
1066 {
1067 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1068 }
1069
fuse_kill_sb_anon(struct super_block * sb)1070 static void fuse_kill_sb_anon(struct super_block *sb)
1071 {
1072 struct fuse_conn *fc = get_fuse_conn_super(sb);
1073
1074 if (fc) {
1075 down_write(&fc->killsb);
1076 fc->sb = NULL;
1077 up_write(&fc->killsb);
1078 }
1079
1080 kill_anon_super(sb);
1081 }
1082
1083 static struct file_system_type fuse_fs_type = {
1084 .owner = THIS_MODULE,
1085 .name = "fuse",
1086 .fs_flags = FS_HAS_SUBTYPE,
1087 .mount = fuse_mount,
1088 .kill_sb = fuse_kill_sb_anon,
1089 };
1090
1091 #ifdef CONFIG_BLOCK
fuse_mount_blk(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data)1092 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1093 int flags, const char *dev_name,
1094 void *raw_data)
1095 {
1096 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1097 }
1098
fuse_kill_sb_blk(struct super_block * sb)1099 static void fuse_kill_sb_blk(struct super_block *sb)
1100 {
1101 struct fuse_conn *fc = get_fuse_conn_super(sb);
1102
1103 if (fc) {
1104 down_write(&fc->killsb);
1105 fc->sb = NULL;
1106 up_write(&fc->killsb);
1107 }
1108
1109 kill_block_super(sb);
1110 }
1111
1112 static struct file_system_type fuseblk_fs_type = {
1113 .owner = THIS_MODULE,
1114 .name = "fuseblk",
1115 .mount = fuse_mount_blk,
1116 .kill_sb = fuse_kill_sb_blk,
1117 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1118 };
1119
register_fuseblk(void)1120 static inline int register_fuseblk(void)
1121 {
1122 return register_filesystem(&fuseblk_fs_type);
1123 }
1124
unregister_fuseblk(void)1125 static inline void unregister_fuseblk(void)
1126 {
1127 unregister_filesystem(&fuseblk_fs_type);
1128 }
1129 #else
register_fuseblk(void)1130 static inline int register_fuseblk(void)
1131 {
1132 return 0;
1133 }
1134
unregister_fuseblk(void)1135 static inline void unregister_fuseblk(void)
1136 {
1137 }
1138 #endif
1139
fuse_inode_init_once(void * foo)1140 static void fuse_inode_init_once(void *foo)
1141 {
1142 struct inode *inode = foo;
1143
1144 inode_init_once(inode);
1145 }
1146
fuse_fs_init(void)1147 static int __init fuse_fs_init(void)
1148 {
1149 int err;
1150
1151 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1152 sizeof(struct fuse_inode),
1153 0, SLAB_HWCACHE_ALIGN,
1154 fuse_inode_init_once);
1155 err = -ENOMEM;
1156 if (!fuse_inode_cachep)
1157 goto out;
1158
1159 err = register_fuseblk();
1160 if (err)
1161 goto out2;
1162
1163 err = register_filesystem(&fuse_fs_type);
1164 if (err)
1165 goto out3;
1166
1167 return 0;
1168
1169 out3:
1170 unregister_fuseblk();
1171 out2:
1172 kmem_cache_destroy(fuse_inode_cachep);
1173 out:
1174 return err;
1175 }
1176
fuse_fs_cleanup(void)1177 static void fuse_fs_cleanup(void)
1178 {
1179 unregister_filesystem(&fuse_fs_type);
1180 unregister_fuseblk();
1181 kmem_cache_destroy(fuse_inode_cachep);
1182 }
1183
1184 static struct kobject *fuse_kobj;
1185 static struct kobject *connections_kobj;
1186
fuse_sysfs_init(void)1187 static int fuse_sysfs_init(void)
1188 {
1189 int err;
1190
1191 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1192 if (!fuse_kobj) {
1193 err = -ENOMEM;
1194 goto out_err;
1195 }
1196
1197 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1198 if (!connections_kobj) {
1199 err = -ENOMEM;
1200 goto out_fuse_unregister;
1201 }
1202
1203 return 0;
1204
1205 out_fuse_unregister:
1206 kobject_put(fuse_kobj);
1207 out_err:
1208 return err;
1209 }
1210
fuse_sysfs_cleanup(void)1211 static void fuse_sysfs_cleanup(void)
1212 {
1213 kobject_put(connections_kobj);
1214 kobject_put(fuse_kobj);
1215 }
1216
fuse_init(void)1217 static int __init fuse_init(void)
1218 {
1219 int res;
1220
1221 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1222 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1223
1224 INIT_LIST_HEAD(&fuse_conn_list);
1225 res = fuse_fs_init();
1226 if (res)
1227 goto err;
1228
1229 res = fuse_dev_init();
1230 if (res)
1231 goto err_fs_cleanup;
1232
1233 res = fuse_sysfs_init();
1234 if (res)
1235 goto err_dev_cleanup;
1236
1237 res = fuse_ctl_init();
1238 if (res)
1239 goto err_sysfs_cleanup;
1240
1241 sanitize_global_limit(&max_user_bgreq);
1242 sanitize_global_limit(&max_user_congthresh);
1243
1244 return 0;
1245
1246 err_sysfs_cleanup:
1247 fuse_sysfs_cleanup();
1248 err_dev_cleanup:
1249 fuse_dev_cleanup();
1250 err_fs_cleanup:
1251 fuse_fs_cleanup();
1252 err:
1253 return res;
1254 }
1255
fuse_exit(void)1256 static void __exit fuse_exit(void)
1257 {
1258 printk(KERN_DEBUG "fuse exit\n");
1259
1260 fuse_ctl_cleanup();
1261 fuse_sysfs_cleanup();
1262 fuse_fs_cleanup();
1263 fuse_dev_cleanup();
1264 }
1265
1266 module_init(fuse_init);
1267 module_exit(fuse_exit);
1268