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()74 struct fuse_forget_link *fuse_alloc_forget()
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 INIT_LIST_HEAD(&fi->write_files);
95 INIT_LIST_HEAD(&fi->queued_writes);
96 INIT_LIST_HEAD(&fi->writepages);
97 init_waitqueue_head(&fi->page_waitq);
98 fi->forget = fuse_alloc_forget();
99 if (!fi->forget) {
100 kmem_cache_free(fuse_inode_cachep, inode);
101 return NULL;
102 }
103
104 return inode;
105 }
106
fuse_i_callback(struct rcu_head * head)107 static void fuse_i_callback(struct rcu_head *head)
108 {
109 struct inode *inode = container_of(head, struct inode, i_rcu);
110 INIT_LIST_HEAD(&inode->i_dentry);
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
fuse_change_attributes_common(struct inode * inode,struct fuse_attr * attr,u64 attr_valid)143 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
144 u64 attr_valid)
145 {
146 struct fuse_conn *fc = get_fuse_conn(inode);
147 struct fuse_inode *fi = get_fuse_inode(inode);
148
149 fi->attr_version = ++fc->attr_version;
150 fi->i_time = attr_valid;
151
152 inode->i_ino = attr->ino;
153 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
154 inode->i_nlink = attr->nlink;
155 inode->i_uid = attr->uid;
156 inode->i_gid = attr->gid;
157 inode->i_blocks = attr->blocks;
158 inode->i_atime.tv_sec = attr->atime;
159 inode->i_atime.tv_nsec = attr->atimensec;
160 inode->i_mtime.tv_sec = attr->mtime;
161 inode->i_mtime.tv_nsec = attr->mtimensec;
162 inode->i_ctime.tv_sec = attr->ctime;
163 inode->i_ctime.tv_nsec = attr->ctimensec;
164
165 if (attr->blksize != 0)
166 inode->i_blkbits = ilog2(attr->blksize);
167 else
168 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
169
170 /*
171 * Don't set the sticky bit in i_mode, unless we want the VFS
172 * to check permissions. This prevents failures due to the
173 * check in may_delete().
174 */
175 fi->orig_i_mode = inode->i_mode;
176 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
177 inode->i_mode &= ~S_ISVTX;
178 }
179
fuse_change_attributes(struct inode * inode,struct fuse_attr * attr,u64 attr_valid,u64 attr_version)180 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
181 u64 attr_valid, u64 attr_version)
182 {
183 struct fuse_conn *fc = get_fuse_conn(inode);
184 struct fuse_inode *fi = get_fuse_inode(inode);
185 loff_t oldsize;
186
187 spin_lock(&fc->lock);
188 if (attr_version != 0 && fi->attr_version > attr_version) {
189 spin_unlock(&fc->lock);
190 return;
191 }
192
193 fuse_change_attributes_common(inode, attr, attr_valid);
194
195 oldsize = inode->i_size;
196 i_size_write(inode, attr->size);
197 spin_unlock(&fc->lock);
198
199 if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
200 truncate_pagecache(inode, oldsize, attr->size);
201 invalidate_inode_pages2(inode->i_mapping);
202 }
203 }
204
fuse_init_inode(struct inode * inode,struct fuse_attr * attr)205 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
206 {
207 inode->i_mode = attr->mode & S_IFMT;
208 inode->i_size = attr->size;
209 if (S_ISREG(inode->i_mode)) {
210 fuse_init_common(inode);
211 fuse_init_file_inode(inode);
212 } else if (S_ISDIR(inode->i_mode))
213 fuse_init_dir(inode);
214 else if (S_ISLNK(inode->i_mode))
215 fuse_init_symlink(inode);
216 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
217 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
218 fuse_init_common(inode);
219 init_special_inode(inode, inode->i_mode,
220 new_decode_dev(attr->rdev));
221 } else
222 BUG();
223 }
224
fuse_inode_eq(struct inode * inode,void * _nodeidp)225 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
226 {
227 u64 nodeid = *(u64 *) _nodeidp;
228 if (get_node_id(inode) == nodeid)
229 return 1;
230 else
231 return 0;
232 }
233
fuse_inode_set(struct inode * inode,void * _nodeidp)234 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
235 {
236 u64 nodeid = *(u64 *) _nodeidp;
237 get_fuse_inode(inode)->nodeid = nodeid;
238 return 0;
239 }
240
fuse_iget(struct super_block * sb,u64 nodeid,int generation,struct fuse_attr * attr,u64 attr_valid,u64 attr_version)241 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
242 int generation, struct fuse_attr *attr,
243 u64 attr_valid, u64 attr_version)
244 {
245 struct inode *inode;
246 struct fuse_inode *fi;
247 struct fuse_conn *fc = get_fuse_conn_super(sb);
248
249 retry:
250 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
251 if (!inode)
252 return NULL;
253
254 if ((inode->i_state & I_NEW)) {
255 inode->i_flags |= S_NOATIME|S_NOCMTIME;
256 inode->i_generation = generation;
257 inode->i_data.backing_dev_info = &fc->bdi;
258 fuse_init_inode(inode, attr);
259 unlock_new_inode(inode);
260 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
261 /* Inode has changed type, any I/O on the old should fail */
262 make_bad_inode(inode);
263 iput(inode);
264 goto retry;
265 }
266
267 fi = get_fuse_inode(inode);
268 spin_lock(&fc->lock);
269 fi->nlookup++;
270 spin_unlock(&fc->lock);
271 fuse_change_attributes(inode, attr, attr_valid, attr_version);
272
273 return inode;
274 }
275
fuse_reverse_inval_inode(struct super_block * sb,u64 nodeid,loff_t offset,loff_t len)276 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
277 loff_t offset, loff_t len)
278 {
279 struct inode *inode;
280 pgoff_t pg_start;
281 pgoff_t pg_end;
282
283 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
284 if (!inode)
285 return -ENOENT;
286
287 fuse_invalidate_attr(inode);
288 if (offset >= 0) {
289 pg_start = offset >> PAGE_CACHE_SHIFT;
290 if (len <= 0)
291 pg_end = -1;
292 else
293 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
294 invalidate_inode_pages2_range(inode->i_mapping,
295 pg_start, pg_end);
296 }
297 iput(inode);
298 return 0;
299 }
300
fuse_umount_begin(struct super_block * sb)301 static void fuse_umount_begin(struct super_block *sb)
302 {
303 fuse_abort_conn(get_fuse_conn_super(sb));
304 }
305
fuse_send_destroy(struct fuse_conn * fc)306 static void fuse_send_destroy(struct fuse_conn *fc)
307 {
308 struct fuse_req *req = fc->destroy_req;
309 if (req && fc->conn_init) {
310 fc->destroy_req = NULL;
311 req->in.h.opcode = FUSE_DESTROY;
312 req->force = 1;
313 fuse_request_send(fc, req);
314 fuse_put_request(fc, req);
315 }
316 }
317
fuse_bdi_destroy(struct fuse_conn * fc)318 static void fuse_bdi_destroy(struct fuse_conn *fc)
319 {
320 if (fc->bdi_initialized)
321 bdi_destroy(&fc->bdi);
322 }
323
fuse_conn_kill(struct fuse_conn * fc)324 void fuse_conn_kill(struct fuse_conn *fc)
325 {
326 spin_lock(&fc->lock);
327 fc->connected = 0;
328 fc->blocked = 0;
329 spin_unlock(&fc->lock);
330 /* Flush all readers on this fs */
331 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
332 wake_up_all(&fc->waitq);
333 wake_up_all(&fc->blocked_waitq);
334 wake_up_all(&fc->reserved_req_waitq);
335 mutex_lock(&fuse_mutex);
336 list_del(&fc->entry);
337 fuse_ctl_remove_conn(fc);
338 mutex_unlock(&fuse_mutex);
339 fuse_bdi_destroy(fc);
340 }
341 EXPORT_SYMBOL_GPL(fuse_conn_kill);
342
fuse_put_super(struct super_block * sb)343 static void fuse_put_super(struct super_block *sb)
344 {
345 struct fuse_conn *fc = get_fuse_conn_super(sb);
346
347 fuse_send_destroy(fc);
348 fuse_conn_kill(fc);
349 fuse_conn_put(fc);
350 }
351
convert_fuse_statfs(struct kstatfs * stbuf,struct fuse_kstatfs * attr)352 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
353 {
354 stbuf->f_type = FUSE_SUPER_MAGIC;
355 stbuf->f_bsize = attr->bsize;
356 stbuf->f_frsize = attr->frsize;
357 stbuf->f_blocks = attr->blocks;
358 stbuf->f_bfree = attr->bfree;
359 stbuf->f_bavail = attr->bavail;
360 stbuf->f_files = attr->files;
361 stbuf->f_ffree = attr->ffree;
362 stbuf->f_namelen = attr->namelen;
363 /* fsid is left zero */
364 }
365
fuse_statfs(struct dentry * dentry,struct kstatfs * buf)366 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
367 {
368 struct super_block *sb = dentry->d_sb;
369 struct fuse_conn *fc = get_fuse_conn_super(sb);
370 struct fuse_req *req;
371 struct fuse_statfs_out outarg;
372 int err;
373
374 if (!fuse_allow_task(fc, current)) {
375 buf->f_type = FUSE_SUPER_MAGIC;
376 return 0;
377 }
378
379 req = fuse_get_req(fc);
380 if (IS_ERR(req))
381 return PTR_ERR(req);
382
383 memset(&outarg, 0, sizeof(outarg));
384 req->in.numargs = 0;
385 req->in.h.opcode = FUSE_STATFS;
386 req->in.h.nodeid = get_node_id(dentry->d_inode);
387 req->out.numargs = 1;
388 req->out.args[0].size =
389 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
390 req->out.args[0].value = &outarg;
391 fuse_request_send(fc, req);
392 err = req->out.h.error;
393 if (!err)
394 convert_fuse_statfs(buf, &outarg.st);
395 fuse_put_request(fc, req);
396 return err;
397 }
398
399 enum {
400 OPT_FD,
401 OPT_ROOTMODE,
402 OPT_USER_ID,
403 OPT_GROUP_ID,
404 OPT_DEFAULT_PERMISSIONS,
405 OPT_ALLOW_OTHER,
406 OPT_MAX_READ,
407 OPT_BLKSIZE,
408 OPT_ERR
409 };
410
411 static const match_table_t tokens = {
412 {OPT_FD, "fd=%u"},
413 {OPT_ROOTMODE, "rootmode=%o"},
414 {OPT_USER_ID, "user_id=%u"},
415 {OPT_GROUP_ID, "group_id=%u"},
416 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
417 {OPT_ALLOW_OTHER, "allow_other"},
418 {OPT_MAX_READ, "max_read=%u"},
419 {OPT_BLKSIZE, "blksize=%u"},
420 {OPT_ERR, NULL}
421 };
422
parse_fuse_opt(char * opt,struct fuse_mount_data * d,int is_bdev)423 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
424 {
425 char *p;
426 memset(d, 0, sizeof(struct fuse_mount_data));
427 d->max_read = ~0;
428 d->blksize = FUSE_DEFAULT_BLKSIZE;
429
430 while ((p = strsep(&opt, ",")) != NULL) {
431 int token;
432 int value;
433 substring_t args[MAX_OPT_ARGS];
434 if (!*p)
435 continue;
436
437 token = match_token(p, tokens, args);
438 switch (token) {
439 case OPT_FD:
440 if (match_int(&args[0], &value))
441 return 0;
442 d->fd = value;
443 d->fd_present = 1;
444 break;
445
446 case OPT_ROOTMODE:
447 if (match_octal(&args[0], &value))
448 return 0;
449 if (!fuse_valid_type(value))
450 return 0;
451 d->rootmode = value;
452 d->rootmode_present = 1;
453 break;
454
455 case OPT_USER_ID:
456 if (match_int(&args[0], &value))
457 return 0;
458 d->user_id = value;
459 d->user_id_present = 1;
460 break;
461
462 case OPT_GROUP_ID:
463 if (match_int(&args[0], &value))
464 return 0;
465 d->group_id = value;
466 d->group_id_present = 1;
467 break;
468
469 case OPT_DEFAULT_PERMISSIONS:
470 d->flags |= FUSE_DEFAULT_PERMISSIONS;
471 break;
472
473 case OPT_ALLOW_OTHER:
474 d->flags |= FUSE_ALLOW_OTHER;
475 break;
476
477 case OPT_MAX_READ:
478 if (match_int(&args[0], &value))
479 return 0;
480 d->max_read = value;
481 break;
482
483 case OPT_BLKSIZE:
484 if (!is_bdev || match_int(&args[0], &value))
485 return 0;
486 d->blksize = value;
487 break;
488
489 default:
490 return 0;
491 }
492 }
493
494 if (!d->fd_present || !d->rootmode_present ||
495 !d->user_id_present || !d->group_id_present)
496 return 0;
497
498 return 1;
499 }
500
fuse_show_options(struct seq_file * m,struct vfsmount * mnt)501 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
502 {
503 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
504
505 seq_printf(m, ",user_id=%u", fc->user_id);
506 seq_printf(m, ",group_id=%u", fc->group_id);
507 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
508 seq_puts(m, ",default_permissions");
509 if (fc->flags & FUSE_ALLOW_OTHER)
510 seq_puts(m, ",allow_other");
511 if (fc->max_read != ~0)
512 seq_printf(m, ",max_read=%u", fc->max_read);
513 if (mnt->mnt_sb->s_bdev &&
514 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
515 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
516 return 0;
517 }
518
fuse_conn_init(struct fuse_conn * fc)519 void fuse_conn_init(struct fuse_conn *fc)
520 {
521 memset(fc, 0, sizeof(*fc));
522 spin_lock_init(&fc->lock);
523 mutex_init(&fc->inst_mutex);
524 init_rwsem(&fc->killsb);
525 atomic_set(&fc->count, 1);
526 init_waitqueue_head(&fc->waitq);
527 init_waitqueue_head(&fc->blocked_waitq);
528 init_waitqueue_head(&fc->reserved_req_waitq);
529 INIT_LIST_HEAD(&fc->pending);
530 INIT_LIST_HEAD(&fc->processing);
531 INIT_LIST_HEAD(&fc->io);
532 INIT_LIST_HEAD(&fc->interrupts);
533 INIT_LIST_HEAD(&fc->bg_queue);
534 INIT_LIST_HEAD(&fc->entry);
535 fc->forget_list_tail = &fc->forget_list_head;
536 atomic_set(&fc->num_waiting, 0);
537 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
538 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
539 fc->khctr = 0;
540 fc->polled_files = RB_ROOT;
541 fc->reqctr = 0;
542 fc->blocked = 1;
543 fc->attr_version = 1;
544 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
545 }
546 EXPORT_SYMBOL_GPL(fuse_conn_init);
547
fuse_conn_put(struct fuse_conn * fc)548 void fuse_conn_put(struct fuse_conn *fc)
549 {
550 if (atomic_dec_and_test(&fc->count)) {
551 if (fc->destroy_req)
552 fuse_request_free(fc->destroy_req);
553 mutex_destroy(&fc->inst_mutex);
554 fc->release(fc);
555 }
556 }
557 EXPORT_SYMBOL_GPL(fuse_conn_put);
558
fuse_conn_get(struct fuse_conn * fc)559 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
560 {
561 atomic_inc(&fc->count);
562 return fc;
563 }
564 EXPORT_SYMBOL_GPL(fuse_conn_get);
565
fuse_get_root_inode(struct super_block * sb,unsigned mode)566 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
567 {
568 struct fuse_attr attr;
569 memset(&attr, 0, sizeof(attr));
570
571 attr.mode = mode;
572 attr.ino = FUSE_ROOT_ID;
573 attr.nlink = 1;
574 return fuse_iget(sb, 1, 0, &attr, 0, 0);
575 }
576
577 struct fuse_inode_handle {
578 u64 nodeid;
579 u32 generation;
580 };
581
fuse_get_dentry(struct super_block * sb,struct fuse_inode_handle * handle)582 static struct dentry *fuse_get_dentry(struct super_block *sb,
583 struct fuse_inode_handle *handle)
584 {
585 struct fuse_conn *fc = get_fuse_conn_super(sb);
586 struct inode *inode;
587 struct dentry *entry;
588 int err = -ESTALE;
589
590 if (handle->nodeid == 0)
591 goto out_err;
592
593 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
594 if (!inode) {
595 struct fuse_entry_out outarg;
596 struct qstr name;
597
598 if (!fc->export_support)
599 goto out_err;
600
601 name.len = 1;
602 name.name = ".";
603 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
604 &inode);
605 if (err && err != -ENOENT)
606 goto out_err;
607 if (err || !inode) {
608 err = -ESTALE;
609 goto out_err;
610 }
611 err = -EIO;
612 if (get_node_id(inode) != handle->nodeid)
613 goto out_iput;
614 }
615 err = -ESTALE;
616 if (inode->i_generation != handle->generation)
617 goto out_iput;
618
619 entry = d_obtain_alias(inode);
620 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
621 fuse_invalidate_entry_cache(entry);
622
623 return entry;
624
625 out_iput:
626 iput(inode);
627 out_err:
628 return ERR_PTR(err);
629 }
630
fuse_encode_fh(struct dentry * dentry,u32 * fh,int * max_len,int connectable)631 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
632 int connectable)
633 {
634 struct inode *inode = dentry->d_inode;
635 bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
636 int len = encode_parent ? 6 : 3;
637 u64 nodeid;
638 u32 generation;
639
640 if (*max_len < len) {
641 *max_len = len;
642 return 255;
643 }
644
645 nodeid = get_fuse_inode(inode)->nodeid;
646 generation = inode->i_generation;
647
648 fh[0] = (u32)(nodeid >> 32);
649 fh[1] = (u32)(nodeid & 0xffffffff);
650 fh[2] = generation;
651
652 if (encode_parent) {
653 struct inode *parent;
654
655 spin_lock(&dentry->d_lock);
656 parent = dentry->d_parent->d_inode;
657 nodeid = get_fuse_inode(parent)->nodeid;
658 generation = parent->i_generation;
659 spin_unlock(&dentry->d_lock);
660
661 fh[3] = (u32)(nodeid >> 32);
662 fh[4] = (u32)(nodeid & 0xffffffff);
663 fh[5] = generation;
664 }
665
666 *max_len = len;
667 return encode_parent ? 0x82 : 0x81;
668 }
669
fuse_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)670 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
671 struct fid *fid, int fh_len, int fh_type)
672 {
673 struct fuse_inode_handle handle;
674
675 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
676 return NULL;
677
678 handle.nodeid = (u64) fid->raw[0] << 32;
679 handle.nodeid |= (u64) fid->raw[1];
680 handle.generation = fid->raw[2];
681 return fuse_get_dentry(sb, &handle);
682 }
683
fuse_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)684 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
685 struct fid *fid, int fh_len, int fh_type)
686 {
687 struct fuse_inode_handle parent;
688
689 if (fh_type != 0x82 || fh_len < 6)
690 return NULL;
691
692 parent.nodeid = (u64) fid->raw[3] << 32;
693 parent.nodeid |= (u64) fid->raw[4];
694 parent.generation = fid->raw[5];
695 return fuse_get_dentry(sb, &parent);
696 }
697
fuse_get_parent(struct dentry * child)698 static struct dentry *fuse_get_parent(struct dentry *child)
699 {
700 struct inode *child_inode = child->d_inode;
701 struct fuse_conn *fc = get_fuse_conn(child_inode);
702 struct inode *inode;
703 struct dentry *parent;
704 struct fuse_entry_out outarg;
705 struct qstr name;
706 int err;
707
708 if (!fc->export_support)
709 return ERR_PTR(-ESTALE);
710
711 name.len = 2;
712 name.name = "..";
713 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
714 &name, &outarg, &inode);
715 if (err) {
716 if (err == -ENOENT)
717 return ERR_PTR(-ESTALE);
718 return ERR_PTR(err);
719 }
720
721 parent = d_obtain_alias(inode);
722 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
723 fuse_invalidate_entry_cache(parent);
724
725 return parent;
726 }
727
728 static const struct export_operations fuse_export_operations = {
729 .fh_to_dentry = fuse_fh_to_dentry,
730 .fh_to_parent = fuse_fh_to_parent,
731 .encode_fh = fuse_encode_fh,
732 .get_parent = fuse_get_parent,
733 };
734
735 static const struct super_operations fuse_super_operations = {
736 .alloc_inode = fuse_alloc_inode,
737 .destroy_inode = fuse_destroy_inode,
738 .evict_inode = fuse_evict_inode,
739 .drop_inode = generic_delete_inode,
740 .remount_fs = fuse_remount_fs,
741 .put_super = fuse_put_super,
742 .umount_begin = fuse_umount_begin,
743 .statfs = fuse_statfs,
744 .show_options = fuse_show_options,
745 };
746
sanitize_global_limit(unsigned * limit)747 static void sanitize_global_limit(unsigned *limit)
748 {
749 if (*limit == 0)
750 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
751 sizeof(struct fuse_req);
752
753 if (*limit >= 1 << 16)
754 *limit = (1 << 16) - 1;
755 }
756
set_global_limit(const char * val,struct kernel_param * kp)757 static int set_global_limit(const char *val, struct kernel_param *kp)
758 {
759 int rv;
760
761 rv = param_set_uint(val, kp);
762 if (rv)
763 return rv;
764
765 sanitize_global_limit((unsigned *)kp->arg);
766
767 return 0;
768 }
769
process_init_limits(struct fuse_conn * fc,struct fuse_init_out * arg)770 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
771 {
772 int cap_sys_admin = capable(CAP_SYS_ADMIN);
773
774 if (arg->minor < 13)
775 return;
776
777 sanitize_global_limit(&max_user_bgreq);
778 sanitize_global_limit(&max_user_congthresh);
779
780 if (arg->max_background) {
781 fc->max_background = arg->max_background;
782
783 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
784 fc->max_background = max_user_bgreq;
785 }
786 if (arg->congestion_threshold) {
787 fc->congestion_threshold = arg->congestion_threshold;
788
789 if (!cap_sys_admin &&
790 fc->congestion_threshold > max_user_congthresh)
791 fc->congestion_threshold = max_user_congthresh;
792 }
793 }
794
process_init_reply(struct fuse_conn * fc,struct fuse_req * req)795 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
796 {
797 struct fuse_init_out *arg = &req->misc.init_out;
798
799 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
800 fc->conn_error = 1;
801 else {
802 unsigned long ra_pages;
803
804 process_init_limits(fc, arg);
805
806 if (arg->minor >= 6) {
807 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
808 if (arg->flags & FUSE_ASYNC_READ)
809 fc->async_read = 1;
810 if (!(arg->flags & FUSE_POSIX_LOCKS))
811 fc->no_lock = 1;
812 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
813 fc->atomic_o_trunc = 1;
814 if (arg->minor >= 9) {
815 /* LOOKUP has dependency on proto version */
816 if (arg->flags & FUSE_EXPORT_SUPPORT)
817 fc->export_support = 1;
818 }
819 if (arg->flags & FUSE_BIG_WRITES)
820 fc->big_writes = 1;
821 if (arg->flags & FUSE_DONT_MASK)
822 fc->dont_mask = 1;
823 } else {
824 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
825 fc->no_lock = 1;
826 }
827
828 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
829 fc->minor = arg->minor;
830 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
831 fc->max_write = max_t(unsigned, 4096, fc->max_write);
832 fc->conn_init = 1;
833 }
834 fc->blocked = 0;
835 wake_up_all(&fc->blocked_waitq);
836 }
837
fuse_send_init(struct fuse_conn * fc,struct fuse_req * req)838 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
839 {
840 struct fuse_init_in *arg = &req->misc.init_in;
841
842 arg->major = FUSE_KERNEL_VERSION;
843 arg->minor = FUSE_KERNEL_MINOR_VERSION;
844 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
845 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
846 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK;
847 req->in.h.opcode = FUSE_INIT;
848 req->in.numargs = 1;
849 req->in.args[0].size = sizeof(*arg);
850 req->in.args[0].value = arg;
851 req->out.numargs = 1;
852 /* Variable length argument used for backward compatibility
853 with interface version < 7.5. Rest of init_out is zeroed
854 by do_get_request(), so a short reply is not a problem */
855 req->out.argvar = 1;
856 req->out.args[0].size = sizeof(struct fuse_init_out);
857 req->out.args[0].value = &req->misc.init_out;
858 req->end = process_init_reply;
859 fuse_request_send_background(fc, req);
860 }
861
fuse_free_conn(struct fuse_conn * fc)862 static void fuse_free_conn(struct fuse_conn *fc)
863 {
864 kfree(fc);
865 }
866
fuse_bdi_init(struct fuse_conn * fc,struct super_block * sb)867 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
868 {
869 int err;
870
871 fc->bdi.name = "fuse";
872 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
873 /* fuse does it's own writeback accounting */
874 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
875
876 err = bdi_init(&fc->bdi);
877 if (err)
878 return err;
879
880 fc->bdi_initialized = 1;
881
882 if (sb->s_bdev) {
883 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
884 MAJOR(fc->dev), MINOR(fc->dev));
885 } else {
886 err = bdi_register_dev(&fc->bdi, fc->dev);
887 }
888
889 if (err)
890 return err;
891
892 /*
893 * For a single fuse filesystem use max 1% of dirty +
894 * writeback threshold.
895 *
896 * This gives about 1M of write buffer for memory maps on a
897 * machine with 1G and 10% dirty_ratio, which should be more
898 * than enough.
899 *
900 * Privileged users can raise it by writing to
901 *
902 * /sys/class/bdi/<bdi>/max_ratio
903 */
904 bdi_set_max_ratio(&fc->bdi, 1);
905
906 return 0;
907 }
908
fuse_fill_super(struct super_block * sb,void * data,int silent)909 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
910 {
911 struct fuse_conn *fc;
912 struct inode *root;
913 struct fuse_mount_data d;
914 struct file *file;
915 struct dentry *root_dentry;
916 struct fuse_req *init_req;
917 int err;
918 int is_bdev = sb->s_bdev != NULL;
919
920 err = -EINVAL;
921 if (sb->s_flags & MS_MANDLOCK)
922 goto err;
923
924 if (!parse_fuse_opt((char *) data, &d, is_bdev))
925 goto err;
926
927 if (is_bdev) {
928 #ifdef CONFIG_BLOCK
929 err = -EINVAL;
930 if (!sb_set_blocksize(sb, d.blksize))
931 goto err;
932 #endif
933 } else {
934 sb->s_blocksize = PAGE_CACHE_SIZE;
935 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
936 }
937 sb->s_magic = FUSE_SUPER_MAGIC;
938 sb->s_op = &fuse_super_operations;
939 sb->s_maxbytes = MAX_LFS_FILESIZE;
940 sb->s_export_op = &fuse_export_operations;
941
942 file = fget(d.fd);
943 err = -EINVAL;
944 if (!file)
945 goto err;
946
947 if (file->f_op != &fuse_dev_operations)
948 goto err_fput;
949
950 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
951 err = -ENOMEM;
952 if (!fc)
953 goto err_fput;
954
955 fuse_conn_init(fc);
956
957 fc->dev = sb->s_dev;
958 fc->sb = sb;
959 err = fuse_bdi_init(fc, sb);
960 if (err)
961 goto err_put_conn;
962
963 sb->s_bdi = &fc->bdi;
964
965 /* Handle umasking inside the fuse code */
966 if (sb->s_flags & MS_POSIXACL)
967 fc->dont_mask = 1;
968 sb->s_flags |= MS_POSIXACL;
969
970 fc->release = fuse_free_conn;
971 fc->flags = d.flags;
972 fc->user_id = d.user_id;
973 fc->group_id = d.group_id;
974 fc->max_read = max_t(unsigned, 4096, d.max_read);
975
976 /* Used by get_root_inode() */
977 sb->s_fs_info = fc;
978
979 err = -ENOMEM;
980 root = fuse_get_root_inode(sb, d.rootmode);
981 if (!root)
982 goto err_put_conn;
983
984 root_dentry = d_alloc_root(root);
985 if (!root_dentry) {
986 iput(root);
987 goto err_put_conn;
988 }
989 /* only now - we want root dentry with NULL ->d_op */
990 sb->s_d_op = &fuse_dentry_operations;
991
992 init_req = fuse_request_alloc();
993 if (!init_req)
994 goto err_put_root;
995
996 if (is_bdev) {
997 fc->destroy_req = fuse_request_alloc();
998 if (!fc->destroy_req)
999 goto err_free_init_req;
1000 }
1001
1002 mutex_lock(&fuse_mutex);
1003 err = -EINVAL;
1004 if (file->private_data)
1005 goto err_unlock;
1006
1007 err = fuse_ctl_add_conn(fc);
1008 if (err)
1009 goto err_unlock;
1010
1011 list_add_tail(&fc->entry, &fuse_conn_list);
1012 sb->s_root = root_dentry;
1013 fc->connected = 1;
1014 file->private_data = fuse_conn_get(fc);
1015 mutex_unlock(&fuse_mutex);
1016 /*
1017 * atomic_dec_and_test() in fput() provides the necessary
1018 * memory barrier for file->private_data to be visible on all
1019 * CPUs after this
1020 */
1021 fput(file);
1022
1023 fuse_send_init(fc, init_req);
1024
1025 return 0;
1026
1027 err_unlock:
1028 mutex_unlock(&fuse_mutex);
1029 err_free_init_req:
1030 fuse_request_free(init_req);
1031 err_put_root:
1032 dput(root_dentry);
1033 err_put_conn:
1034 fuse_bdi_destroy(fc);
1035 fuse_conn_put(fc);
1036 err_fput:
1037 fput(file);
1038 err:
1039 return err;
1040 }
1041
fuse_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data)1042 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1043 int flags, const char *dev_name,
1044 void *raw_data)
1045 {
1046 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1047 }
1048
fuse_kill_sb_anon(struct super_block * sb)1049 static void fuse_kill_sb_anon(struct super_block *sb)
1050 {
1051 struct fuse_conn *fc = get_fuse_conn_super(sb);
1052
1053 if (fc) {
1054 down_write(&fc->killsb);
1055 fc->sb = NULL;
1056 up_write(&fc->killsb);
1057 }
1058
1059 kill_anon_super(sb);
1060 }
1061
1062 static struct file_system_type fuse_fs_type = {
1063 .owner = THIS_MODULE,
1064 .name = "fuse",
1065 .fs_flags = FS_HAS_SUBTYPE,
1066 .mount = fuse_mount,
1067 .kill_sb = fuse_kill_sb_anon,
1068 };
1069
1070 #ifdef CONFIG_BLOCK
fuse_mount_blk(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data)1071 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1072 int flags, const char *dev_name,
1073 void *raw_data)
1074 {
1075 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1076 }
1077
fuse_kill_sb_blk(struct super_block * sb)1078 static void fuse_kill_sb_blk(struct super_block *sb)
1079 {
1080 struct fuse_conn *fc = get_fuse_conn_super(sb);
1081
1082 if (fc) {
1083 down_write(&fc->killsb);
1084 fc->sb = NULL;
1085 up_write(&fc->killsb);
1086 }
1087
1088 kill_block_super(sb);
1089 }
1090
1091 static struct file_system_type fuseblk_fs_type = {
1092 .owner = THIS_MODULE,
1093 .name = "fuseblk",
1094 .mount = fuse_mount_blk,
1095 .kill_sb = fuse_kill_sb_blk,
1096 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1097 };
1098
register_fuseblk(void)1099 static inline int register_fuseblk(void)
1100 {
1101 return register_filesystem(&fuseblk_fs_type);
1102 }
1103
unregister_fuseblk(void)1104 static inline void unregister_fuseblk(void)
1105 {
1106 unregister_filesystem(&fuseblk_fs_type);
1107 }
1108 #else
register_fuseblk(void)1109 static inline int register_fuseblk(void)
1110 {
1111 return 0;
1112 }
1113
unregister_fuseblk(void)1114 static inline void unregister_fuseblk(void)
1115 {
1116 }
1117 #endif
1118
fuse_inode_init_once(void * foo)1119 static void fuse_inode_init_once(void *foo)
1120 {
1121 struct inode *inode = foo;
1122
1123 inode_init_once(inode);
1124 }
1125
fuse_fs_init(void)1126 static int __init fuse_fs_init(void)
1127 {
1128 int err;
1129
1130 err = register_filesystem(&fuse_fs_type);
1131 if (err)
1132 goto out;
1133
1134 err = register_fuseblk();
1135 if (err)
1136 goto out_unreg;
1137
1138 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1139 sizeof(struct fuse_inode),
1140 0, SLAB_HWCACHE_ALIGN,
1141 fuse_inode_init_once);
1142 err = -ENOMEM;
1143 if (!fuse_inode_cachep)
1144 goto out_unreg2;
1145
1146 return 0;
1147
1148 out_unreg2:
1149 unregister_fuseblk();
1150 out_unreg:
1151 unregister_filesystem(&fuse_fs_type);
1152 out:
1153 return err;
1154 }
1155
fuse_fs_cleanup(void)1156 static void fuse_fs_cleanup(void)
1157 {
1158 unregister_filesystem(&fuse_fs_type);
1159 unregister_fuseblk();
1160 kmem_cache_destroy(fuse_inode_cachep);
1161 }
1162
1163 static struct kobject *fuse_kobj;
1164 static struct kobject *connections_kobj;
1165
fuse_sysfs_init(void)1166 static int fuse_sysfs_init(void)
1167 {
1168 int err;
1169
1170 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1171 if (!fuse_kobj) {
1172 err = -ENOMEM;
1173 goto out_err;
1174 }
1175
1176 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1177 if (!connections_kobj) {
1178 err = -ENOMEM;
1179 goto out_fuse_unregister;
1180 }
1181
1182 return 0;
1183
1184 out_fuse_unregister:
1185 kobject_put(fuse_kobj);
1186 out_err:
1187 return err;
1188 }
1189
fuse_sysfs_cleanup(void)1190 static void fuse_sysfs_cleanup(void)
1191 {
1192 kobject_put(connections_kobj);
1193 kobject_put(fuse_kobj);
1194 }
1195
fuse_init(void)1196 static int __init fuse_init(void)
1197 {
1198 int res;
1199
1200 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1201 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1202
1203 INIT_LIST_HEAD(&fuse_conn_list);
1204 res = fuse_fs_init();
1205 if (res)
1206 goto err;
1207
1208 res = fuse_dev_init();
1209 if (res)
1210 goto err_fs_cleanup;
1211
1212 res = fuse_sysfs_init();
1213 if (res)
1214 goto err_dev_cleanup;
1215
1216 res = fuse_ctl_init();
1217 if (res)
1218 goto err_sysfs_cleanup;
1219
1220 sanitize_global_limit(&max_user_bgreq);
1221 sanitize_global_limit(&max_user_congthresh);
1222
1223 return 0;
1224
1225 err_sysfs_cleanup:
1226 fuse_sysfs_cleanup();
1227 err_dev_cleanup:
1228 fuse_dev_cleanup();
1229 err_fs_cleanup:
1230 fuse_fs_cleanup();
1231 err:
1232 return res;
1233 }
1234
fuse_exit(void)1235 static void __exit fuse_exit(void)
1236 {
1237 printk(KERN_DEBUG "fuse exit\n");
1238
1239 fuse_ctl_cleanup();
1240 fuse_sysfs_cleanup();
1241 fuse_fs_cleanup();
1242 fuse_dev_cleanup();
1243 }
1244
1245 module_init(fuse_init);
1246 module_exit(fuse_exit);
1247