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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
24MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
25MODULE_DESCRIPTION("Filesystem in Userspace");
26MODULE_LICENSE("GPL");
27
28static struct kmem_cache *fuse_inode_cachep;
29struct list_head fuse_conn_list;
30DEFINE_MUTEX(fuse_mutex);
31
32static int set_global_limit(const char *val, struct kernel_param *kp);
33
34unsigned max_user_bgreq;
35module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
36 &max_user_bgreq, 0644);
37__MODULE_PARM_TYPE(max_user_bgreq, "uint");
38MODULE_PARM_DESC(max_user_bgreq,
39 "Global limit for the maximum number of backgrounded requests an "
40 "unprivileged user can set");
41
42unsigned max_user_congthresh;
43module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
44 &max_user_congthresh, 0644);
45__MODULE_PARM_TYPE(max_user_congthresh, "uint");
46MODULE_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
60struct 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
74struct fuse_forget_link *fuse_alloc_forget(void)
75{
76 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
77}
78
79static 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
108static 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
114static 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
123static 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
135static 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 */
147static 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
155void 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
194void 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
219static 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
239int 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
248static 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
255struct 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
290int 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
315static void fuse_umount_begin(struct super_block *sb)
316{
317 fuse_abort_conn(get_fuse_conn_super(sb));
318}
319
320static 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
332static void fuse_bdi_destroy(struct fuse_conn *fc)
333{
334 if (fc->bdi_initialized)
335 bdi_destroy(&fc->bdi);
336}
337
338void 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}
355EXPORT_SYMBOL_GPL(fuse_conn_kill);
356
357static 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
366static 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
380static 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
413enum {
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
425static 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
437static 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
515static 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
533void 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}
560EXPORT_SYMBOL_GPL(fuse_conn_init);
561
562void 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}
571EXPORT_SYMBOL_GPL(fuse_conn_put);
572
573struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
574{
575 atomic_inc(&fc->count);
576 return fc;
577}
578EXPORT_SYMBOL_GPL(fuse_conn_get);
579
580static 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
591struct fuse_inode_handle {
592 u64 nodeid;
593 u32 generation;
594};
595
596static 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
645static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
646 struct inode *parent)
647{
648 int len = parent ? 6 : 3;
649 u64 nodeid;
650 u32 generation;
651
652 if (*max_len < len) {
653 *max_len = len;
654 return 255;
655 }
656
657 nodeid = get_fuse_inode(inode)->nodeid;
658 generation = inode->i_generation;
659
660 fh[0] = (u32)(nodeid >> 32);
661 fh[1] = (u32)(nodeid & 0xffffffff);
662 fh[2] = generation;
663
664 if (parent) {
665 nodeid = get_fuse_inode(parent)->nodeid;
666 generation = parent->i_generation;
667
668 fh[3] = (u32)(nodeid >> 32);
669 fh[4] = (u32)(nodeid & 0xffffffff);
670 fh[5] = generation;
671 }
672
673 *max_len = len;
674 return parent ? 0x82 : 0x81;
675}
676
677static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
678 struct fid *fid, int fh_len, int fh_type)
679{
680 struct fuse_inode_handle handle;
681
682 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
683 return NULL;
684
685 handle.nodeid = (u64) fid->raw[0] << 32;
686 handle.nodeid |= (u64) fid->raw[1];
687 handle.generation = fid->raw[2];
688 return fuse_get_dentry(sb, &handle);
689}
690
691static struct dentry *fuse_fh_to_parent(struct super_block *sb,
692 struct fid *fid, int fh_len, int fh_type)
693{
694 struct fuse_inode_handle parent;
695
696 if (fh_type != 0x82 || fh_len < 6)
697 return NULL;
698
699 parent.nodeid = (u64) fid->raw[3] << 32;
700 parent.nodeid |= (u64) fid->raw[4];
701 parent.generation = fid->raw[5];
702 return fuse_get_dentry(sb, &parent);
703}
704
705static struct dentry *fuse_get_parent(struct dentry *child)
706{
707 struct inode *child_inode = child->d_inode;
708 struct fuse_conn *fc = get_fuse_conn(child_inode);
709 struct inode *inode;
710 struct dentry *parent;
711 struct fuse_entry_out outarg;
712 struct qstr name;
713 int err;
714
715 if (!fc->export_support)
716 return ERR_PTR(-ESTALE);
717
718 name.len = 2;
719 name.name = "..";
720 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
721 &name, &outarg, &inode);
722 if (err) {
723 if (err == -ENOENT)
724 return ERR_PTR(-ESTALE);
725 return ERR_PTR(err);
726 }
727
728 parent = d_obtain_alias(inode);
729 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
730 fuse_invalidate_entry_cache(parent);
731
732 return parent;
733}
734
735static const struct export_operations fuse_export_operations = {
736 .fh_to_dentry = fuse_fh_to_dentry,
737 .fh_to_parent = fuse_fh_to_parent,
738 .encode_fh = fuse_encode_fh,
739 .get_parent = fuse_get_parent,
740};
741
742static const struct super_operations fuse_super_operations = {
743 .alloc_inode = fuse_alloc_inode,
744 .destroy_inode = fuse_destroy_inode,
745 .evict_inode = fuse_evict_inode,
746 .drop_inode = generic_delete_inode,
747 .remount_fs = fuse_remount_fs,
748 .put_super = fuse_put_super,
749 .umount_begin = fuse_umount_begin,
750 .statfs = fuse_statfs,
751 .show_options = fuse_show_options,
752};
753
754static void sanitize_global_limit(unsigned *limit)
755{
756 if (*limit == 0)
757 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
758 sizeof(struct fuse_req);
759
760 if (*limit >= 1 << 16)
761 *limit = (1 << 16) - 1;
762}
763
764static int set_global_limit(const char *val, struct kernel_param *kp)
765{
766 int rv;
767
768 rv = param_set_uint(val, kp);
769 if (rv)
770 return rv;
771
772 sanitize_global_limit((unsigned *)kp->arg);
773
774 return 0;
775}
776
777static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
778{
779 int cap_sys_admin = capable(CAP_SYS_ADMIN);
780
781 if (arg->minor < 13)
782 return;
783
784 sanitize_global_limit(&max_user_bgreq);
785 sanitize_global_limit(&max_user_congthresh);
786
787 if (arg->max_background) {
788 fc->max_background = arg->max_background;
789
790 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
791 fc->max_background = max_user_bgreq;
792 }
793 if (arg->congestion_threshold) {
794 fc->congestion_threshold = arg->congestion_threshold;
795
796 if (!cap_sys_admin &&
797 fc->congestion_threshold > max_user_congthresh)
798 fc->congestion_threshold = max_user_congthresh;
799 }
800}
801
802static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
803{
804 struct fuse_init_out *arg = &req->misc.init_out;
805
806 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
807 fc->conn_error = 1;
808 else {
809 unsigned long ra_pages;
810
811 process_init_limits(fc, arg);
812
813 if (arg->minor >= 6) {
814 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
815 if (arg->flags & FUSE_ASYNC_READ)
816 fc->async_read = 1;
817 if (!(arg->flags & FUSE_POSIX_LOCKS))
818 fc->no_lock = 1;
819 if (arg->minor >= 17) {
820 if (!(arg->flags & FUSE_FLOCK_LOCKS))
821 fc->no_flock = 1;
822 } else {
823 if (!(arg->flags & FUSE_POSIX_LOCKS))
824 fc->no_flock = 1;
825 }
826 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
827 fc->atomic_o_trunc = 1;
828 if (arg->minor >= 9) {
829 /* LOOKUP has dependency on proto version */
830 if (arg->flags & FUSE_EXPORT_SUPPORT)
831 fc->export_support = 1;
832 }
833 if (arg->flags & FUSE_BIG_WRITES)
834 fc->big_writes = 1;
835 if (arg->flags & FUSE_DONT_MASK)
836 fc->dont_mask = 1;
837 } else {
838 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
839 fc->no_lock = 1;
840 fc->no_flock = 1;
841 }
842
843 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
844 fc->minor = arg->minor;
845 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
846 fc->max_write = max_t(unsigned, 4096, fc->max_write);
847 fc->conn_init = 1;
848 }
849 fc->blocked = 0;
850 wake_up_all(&fc->blocked_waitq);
851}
852
853static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
854{
855 struct fuse_init_in *arg = &req->misc.init_in;
856
857 arg->major = FUSE_KERNEL_VERSION;
858 arg->minor = FUSE_KERNEL_MINOR_VERSION;
859 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
860 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
861 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
862 FUSE_FLOCK_LOCKS;
863 req->in.h.opcode = FUSE_INIT;
864 req->in.numargs = 1;
865 req->in.args[0].size = sizeof(*arg);
866 req->in.args[0].value = arg;
867 req->out.numargs = 1;
868 /* Variable length argument used for backward compatibility
869 with interface version < 7.5. Rest of init_out is zeroed
870 by do_get_request(), so a short reply is not a problem */
871 req->out.argvar = 1;
872 req->out.args[0].size = sizeof(struct fuse_init_out);
873 req->out.args[0].value = &req->misc.init_out;
874 req->end = process_init_reply;
875 fuse_request_send_background(fc, req);
876}
877
878static void fuse_free_conn(struct fuse_conn *fc)
879{
880 kfree(fc);
881}
882
883static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
884{
885 int err;
886
887 fc->bdi.name = "fuse";
888 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
889 /* fuse does it's own writeback accounting */
890 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
891
892 err = bdi_init(&fc->bdi);
893 if (err)
894 return err;
895
896 fc->bdi_initialized = 1;
897
898 if (sb->s_bdev) {
899 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
900 MAJOR(fc->dev), MINOR(fc->dev));
901 } else {
902 err = bdi_register_dev(&fc->bdi, fc->dev);
903 }
904
905 if (err)
906 return err;
907
908 /*
909 * For a single fuse filesystem use max 1% of dirty +
910 * writeback threshold.
911 *
912 * This gives about 1M of write buffer for memory maps on a
913 * machine with 1G and 10% dirty_ratio, which should be more
914 * than enough.
915 *
916 * Privileged users can raise it by writing to
917 *
918 * /sys/class/bdi/<bdi>/max_ratio
919 */
920 bdi_set_max_ratio(&fc->bdi, 1);
921
922 return 0;
923}
924
925static int fuse_fill_super(struct super_block *sb, void *data, int silent)
926{
927 struct fuse_conn *fc;
928 struct inode *root;
929 struct fuse_mount_data d;
930 struct file *file;
931 struct dentry *root_dentry;
932 struct fuse_req *init_req;
933 int err;
934 int is_bdev = sb->s_bdev != NULL;
935
936 err = -EINVAL;
937 if (sb->s_flags & MS_MANDLOCK)
938 goto err;
939
940 sb->s_flags &= ~MS_NOSEC;
941
942 if (!parse_fuse_opt((char *) data, &d, is_bdev))
943 goto err;
944
945 if (is_bdev) {
946#ifdef CONFIG_BLOCK
947 err = -EINVAL;
948 if (!sb_set_blocksize(sb, d.blksize))
949 goto err;
950#endif
951 } else {
952 sb->s_blocksize = PAGE_CACHE_SIZE;
953 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
954 }
955 sb->s_magic = FUSE_SUPER_MAGIC;
956 sb->s_op = &fuse_super_operations;
957 sb->s_maxbytes = MAX_LFS_FILESIZE;
958 sb->s_time_gran = 1;
959 sb->s_export_op = &fuse_export_operations;
960
961 file = fget(d.fd);
962 err = -EINVAL;
963 if (!file)
964 goto err;
965
966 if (file->f_op != &fuse_dev_operations)
967 goto err_fput;
968
969 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
970 err = -ENOMEM;
971 if (!fc)
972 goto err_fput;
973
974 fuse_conn_init(fc);
975
976 fc->dev = sb->s_dev;
977 fc->sb = sb;
978 err = fuse_bdi_init(fc, sb);
979 if (err)
980 goto err_put_conn;
981
982 sb->s_bdi = &fc->bdi;
983
984 /* Handle umasking inside the fuse code */
985 if (sb->s_flags & MS_POSIXACL)
986 fc->dont_mask = 1;
987 sb->s_flags |= MS_POSIXACL;
988
989 fc->release = fuse_free_conn;
990 fc->flags = d.flags;
991 fc->user_id = d.user_id;
992 fc->group_id = d.group_id;
993 fc->max_read = max_t(unsigned, 4096, d.max_read);
994
995 /* Used by get_root_inode() */
996 sb->s_fs_info = fc;
997
998 err = -ENOMEM;
999 root = fuse_get_root_inode(sb, d.rootmode);
1000 root_dentry = d_make_root(root);
1001 if (!root_dentry)
1002 goto err_put_conn;
1003 /* only now - we want root dentry with NULL ->d_op */
1004 sb->s_d_op = &fuse_dentry_operations;
1005
1006 init_req = fuse_request_alloc();
1007 if (!init_req)
1008 goto err_put_root;
1009
1010 if (is_bdev) {
1011 fc->destroy_req = fuse_request_alloc();
1012 if (!fc->destroy_req)
1013 goto err_free_init_req;
1014 }
1015
1016 mutex_lock(&fuse_mutex);
1017 err = -EINVAL;
1018 if (file->private_data)
1019 goto err_unlock;
1020
1021 err = fuse_ctl_add_conn(fc);
1022 if (err)
1023 goto err_unlock;
1024
1025 list_add_tail(&fc->entry, &fuse_conn_list);
1026 sb->s_root = root_dentry;
1027 fc->connected = 1;
1028 file->private_data = fuse_conn_get(fc);
1029 mutex_unlock(&fuse_mutex);
1030 /*
1031 * atomic_dec_and_test() in fput() provides the necessary
1032 * memory barrier for file->private_data to be visible on all
1033 * CPUs after this
1034 */
1035 fput(file);
1036
1037 fuse_send_init(fc, init_req);
1038
1039 return 0;
1040
1041 err_unlock:
1042 mutex_unlock(&fuse_mutex);
1043 err_free_init_req:
1044 fuse_request_free(init_req);
1045 err_put_root:
1046 dput(root_dentry);
1047 err_put_conn:
1048 fuse_bdi_destroy(fc);
1049 fuse_conn_put(fc);
1050 err_fput:
1051 fput(file);
1052 err:
1053 return err;
1054}
1055
1056static struct dentry *fuse_mount(struct file_system_type *fs_type,
1057 int flags, const char *dev_name,
1058 void *raw_data)
1059{
1060 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1061}
1062
1063static void fuse_kill_sb_anon(struct super_block *sb)
1064{
1065 struct fuse_conn *fc = get_fuse_conn_super(sb);
1066
1067 if (fc) {
1068 down_write(&fc->killsb);
1069 fc->sb = NULL;
1070 up_write(&fc->killsb);
1071 }
1072
1073 kill_anon_super(sb);
1074}
1075
1076static struct file_system_type fuse_fs_type = {
1077 .owner = THIS_MODULE,
1078 .name = "fuse",
1079 .fs_flags = FS_HAS_SUBTYPE,
1080 .mount = fuse_mount,
1081 .kill_sb = fuse_kill_sb_anon,
1082};
1083
1084#ifdef CONFIG_BLOCK
1085static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1086 int flags, const char *dev_name,
1087 void *raw_data)
1088{
1089 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1090}
1091
1092static void fuse_kill_sb_blk(struct super_block *sb)
1093{
1094 struct fuse_conn *fc = get_fuse_conn_super(sb);
1095
1096 if (fc) {
1097 down_write(&fc->killsb);
1098 fc->sb = NULL;
1099 up_write(&fc->killsb);
1100 }
1101
1102 kill_block_super(sb);
1103}
1104
1105static struct file_system_type fuseblk_fs_type = {
1106 .owner = THIS_MODULE,
1107 .name = "fuseblk",
1108 .mount = fuse_mount_blk,
1109 .kill_sb = fuse_kill_sb_blk,
1110 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1111};
1112
1113static inline int register_fuseblk(void)
1114{
1115 return register_filesystem(&fuseblk_fs_type);
1116}
1117
1118static inline void unregister_fuseblk(void)
1119{
1120 unregister_filesystem(&fuseblk_fs_type);
1121}
1122#else
1123static inline int register_fuseblk(void)
1124{
1125 return 0;
1126}
1127
1128static inline void unregister_fuseblk(void)
1129{
1130}
1131#endif
1132
1133static void fuse_inode_init_once(void *foo)
1134{
1135 struct inode *inode = foo;
1136
1137 inode_init_once(inode);
1138}
1139
1140static int __init fuse_fs_init(void)
1141{
1142 int err;
1143
1144 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1145 sizeof(struct fuse_inode),
1146 0, SLAB_HWCACHE_ALIGN,
1147 fuse_inode_init_once);
1148 err = -ENOMEM;
1149 if (!fuse_inode_cachep)
1150 goto out;
1151
1152 err = register_fuseblk();
1153 if (err)
1154 goto out2;
1155
1156 err = register_filesystem(&fuse_fs_type);
1157 if (err)
1158 goto out3;
1159
1160 return 0;
1161
1162 out3:
1163 unregister_fuseblk();
1164 out2:
1165 kmem_cache_destroy(fuse_inode_cachep);
1166 out:
1167 return err;
1168}
1169
1170static void fuse_fs_cleanup(void)
1171{
1172 unregister_filesystem(&fuse_fs_type);
1173 unregister_fuseblk();
1174 kmem_cache_destroy(fuse_inode_cachep);
1175}
1176
1177static struct kobject *fuse_kobj;
1178static struct kobject *connections_kobj;
1179
1180static int fuse_sysfs_init(void)
1181{
1182 int err;
1183
1184 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1185 if (!fuse_kobj) {
1186 err = -ENOMEM;
1187 goto out_err;
1188 }
1189
1190 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1191 if (!connections_kobj) {
1192 err = -ENOMEM;
1193 goto out_fuse_unregister;
1194 }
1195
1196 return 0;
1197
1198 out_fuse_unregister:
1199 kobject_put(fuse_kobj);
1200 out_err:
1201 return err;
1202}
1203
1204static void fuse_sysfs_cleanup(void)
1205{
1206 kobject_put(connections_kobj);
1207 kobject_put(fuse_kobj);
1208}
1209
1210static int __init fuse_init(void)
1211{
1212 int res;
1213
1214 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1215 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1216
1217 INIT_LIST_HEAD(&fuse_conn_list);
1218 res = fuse_fs_init();
1219 if (res)
1220 goto err;
1221
1222 res = fuse_dev_init();
1223 if (res)
1224 goto err_fs_cleanup;
1225
1226 res = fuse_sysfs_init();
1227 if (res)
1228 goto err_dev_cleanup;
1229
1230 res = fuse_ctl_init();
1231 if (res)
1232 goto err_sysfs_cleanup;
1233
1234 sanitize_global_limit(&max_user_bgreq);
1235 sanitize_global_limit(&max_user_congthresh);
1236
1237 return 0;
1238
1239 err_sysfs_cleanup:
1240 fuse_sysfs_cleanup();
1241 err_dev_cleanup:
1242 fuse_dev_cleanup();
1243 err_fs_cleanup:
1244 fuse_fs_cleanup();
1245 err:
1246 return res;
1247}
1248
1249static void __exit fuse_exit(void)
1250{
1251 printk(KERN_DEBUG "fuse exit\n");
1252
1253 fuse_ctl_cleanup();
1254 fuse_sysfs_cleanup();
1255 fuse_fs_cleanup();
1256 fuse_dev_cleanup();
1257}
1258
1259module_init(fuse_init);
1260module_exit(fuse_exit);
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/fs_context.h>
19#include <linux/fs_parser.h>
20#include <linux/statfs.h>
21#include <linux/random.h>
22#include <linux/sched.h>
23#include <linux/exportfs.h>
24#include <linux/posix_acl.h>
25#include <linux/pid_namespace.h>
26
27MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
28MODULE_DESCRIPTION("Filesystem in Userspace");
29MODULE_LICENSE("GPL");
30
31static struct kmem_cache *fuse_inode_cachep;
32struct list_head fuse_conn_list;
33DEFINE_MUTEX(fuse_mutex);
34
35static int set_global_limit(const char *val, const struct kernel_param *kp);
36
37unsigned max_user_bgreq;
38module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
39 &max_user_bgreq, 0644);
40__MODULE_PARM_TYPE(max_user_bgreq, "uint");
41MODULE_PARM_DESC(max_user_bgreq,
42 "Global limit for the maximum number of backgrounded requests an "
43 "unprivileged user can set");
44
45unsigned max_user_congthresh;
46module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
47 &max_user_congthresh, 0644);
48__MODULE_PARM_TYPE(max_user_congthresh, "uint");
49MODULE_PARM_DESC(max_user_congthresh,
50 "Global limit for the maximum congestion threshold an "
51 "unprivileged user can set");
52
53#define FUSE_SUPER_MAGIC 0x65735546
54
55#define FUSE_DEFAULT_BLKSIZE 512
56
57/** Maximum number of outstanding background requests */
58#define FUSE_DEFAULT_MAX_BACKGROUND 12
59
60/** Congestion starts at 75% of maximum */
61#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
62
63#ifdef CONFIG_BLOCK
64static struct file_system_type fuseblk_fs_type;
65#endif
66
67struct fuse_forget_link *fuse_alloc_forget(void)
68{
69 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
70}
71
72static struct inode *fuse_alloc_inode(struct super_block *sb)
73{
74 struct fuse_inode *fi;
75
76 fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
77 if (!fi)
78 return NULL;
79
80 fi->i_time = 0;
81 fi->inval_mask = 0;
82 fi->nodeid = 0;
83 fi->nlookup = 0;
84 fi->attr_version = 0;
85 fi->orig_ino = 0;
86 fi->state = 0;
87 mutex_init(&fi->mutex);
88 spin_lock_init(&fi->lock);
89 fi->forget = fuse_alloc_forget();
90 if (!fi->forget) {
91 kmem_cache_free(fuse_inode_cachep, fi);
92 return NULL;
93 }
94
95 return &fi->inode;
96}
97
98static void fuse_free_inode(struct inode *inode)
99{
100 struct fuse_inode *fi = get_fuse_inode(inode);
101
102 mutex_destroy(&fi->mutex);
103 kfree(fi->forget);
104 kmem_cache_free(fuse_inode_cachep, fi);
105}
106
107static void fuse_evict_inode(struct inode *inode)
108{
109 struct fuse_inode *fi = get_fuse_inode(inode);
110
111 truncate_inode_pages_final(&inode->i_data);
112 clear_inode(inode);
113 if (inode->i_sb->s_flags & SB_ACTIVE) {
114 struct fuse_conn *fc = get_fuse_conn(inode);
115 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
116 fi->forget = NULL;
117 }
118 if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {
119 WARN_ON(!list_empty(&fi->write_files));
120 WARN_ON(!list_empty(&fi->queued_writes));
121 }
122}
123
124static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
125{
126 sync_filesystem(sb);
127 if (*flags & SB_MANDLOCK)
128 return -EINVAL;
129
130 return 0;
131}
132
133/*
134 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
135 * so that it will fit.
136 */
137static ino_t fuse_squash_ino(u64 ino64)
138{
139 ino_t ino = (ino_t) ino64;
140 if (sizeof(ino_t) < sizeof(u64))
141 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
142 return ino;
143}
144
145void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
146 u64 attr_valid)
147{
148 struct fuse_conn *fc = get_fuse_conn(inode);
149 struct fuse_inode *fi = get_fuse_inode(inode);
150
151 lockdep_assert_held(&fi->lock);
152
153 fi->attr_version = atomic64_inc_return(&fc->attr_version);
154 fi->i_time = attr_valid;
155 WRITE_ONCE(fi->inval_mask, 0);
156
157 inode->i_ino = fuse_squash_ino(attr->ino);
158 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
159 set_nlink(inode, attr->nlink);
160 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
161 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
162 inode->i_blocks = attr->blocks;
163 inode->i_atime.tv_sec = attr->atime;
164 inode->i_atime.tv_nsec = attr->atimensec;
165 /* mtime from server may be stale due to local buffered write */
166 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
167 inode->i_mtime.tv_sec = attr->mtime;
168 inode->i_mtime.tv_nsec = attr->mtimensec;
169 inode->i_ctime.tv_sec = attr->ctime;
170 inode->i_ctime.tv_nsec = attr->ctimensec;
171 }
172
173 if (attr->blksize != 0)
174 inode->i_blkbits = ilog2(attr->blksize);
175 else
176 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
177
178 /*
179 * Don't set the sticky bit in i_mode, unless we want the VFS
180 * to check permissions. This prevents failures due to the
181 * check in may_delete().
182 */
183 fi->orig_i_mode = inode->i_mode;
184 if (!fc->default_permissions)
185 inode->i_mode &= ~S_ISVTX;
186
187 fi->orig_ino = attr->ino;
188}
189
190void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
191 u64 attr_valid, u64 attr_version)
192{
193 struct fuse_conn *fc = get_fuse_conn(inode);
194 struct fuse_inode *fi = get_fuse_inode(inode);
195 bool is_wb = fc->writeback_cache;
196 loff_t oldsize;
197 struct timespec64 old_mtime;
198
199 spin_lock(&fi->lock);
200 if ((attr_version != 0 && fi->attr_version > attr_version) ||
201 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
202 spin_unlock(&fi->lock);
203 return;
204 }
205
206 old_mtime = inode->i_mtime;
207 fuse_change_attributes_common(inode, attr, attr_valid);
208
209 oldsize = inode->i_size;
210 /*
211 * In case of writeback_cache enabled, the cached writes beyond EOF
212 * extend local i_size without keeping userspace server in sync. So,
213 * attr->size coming from server can be stale. We cannot trust it.
214 */
215 if (!is_wb || !S_ISREG(inode->i_mode))
216 i_size_write(inode, attr->size);
217 spin_unlock(&fi->lock);
218
219 if (!is_wb && S_ISREG(inode->i_mode)) {
220 bool inval = false;
221
222 if (oldsize != attr->size) {
223 truncate_pagecache(inode, attr->size);
224 if (!fc->explicit_inval_data)
225 inval = true;
226 } else if (fc->auto_inval_data) {
227 struct timespec64 new_mtime = {
228 .tv_sec = attr->mtime,
229 .tv_nsec = attr->mtimensec,
230 };
231
232 /*
233 * Auto inval mode also checks and invalidates if mtime
234 * has changed.
235 */
236 if (!timespec64_equal(&old_mtime, &new_mtime))
237 inval = true;
238 }
239
240 if (inval)
241 invalidate_inode_pages2(inode->i_mapping);
242 }
243}
244
245static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
246{
247 inode->i_mode = attr->mode & S_IFMT;
248 inode->i_size = attr->size;
249 inode->i_mtime.tv_sec = attr->mtime;
250 inode->i_mtime.tv_nsec = attr->mtimensec;
251 inode->i_ctime.tv_sec = attr->ctime;
252 inode->i_ctime.tv_nsec = attr->ctimensec;
253 if (S_ISREG(inode->i_mode)) {
254 fuse_init_common(inode);
255 fuse_init_file_inode(inode);
256 } else if (S_ISDIR(inode->i_mode))
257 fuse_init_dir(inode);
258 else if (S_ISLNK(inode->i_mode))
259 fuse_init_symlink(inode);
260 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
261 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
262 fuse_init_common(inode);
263 init_special_inode(inode, inode->i_mode,
264 new_decode_dev(attr->rdev));
265 } else
266 BUG();
267}
268
269int fuse_inode_eq(struct inode *inode, void *_nodeidp)
270{
271 u64 nodeid = *(u64 *) _nodeidp;
272 if (get_node_id(inode) == nodeid)
273 return 1;
274 else
275 return 0;
276}
277
278static int fuse_inode_set(struct inode *inode, void *_nodeidp)
279{
280 u64 nodeid = *(u64 *) _nodeidp;
281 get_fuse_inode(inode)->nodeid = nodeid;
282 return 0;
283}
284
285struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
286 int generation, struct fuse_attr *attr,
287 u64 attr_valid, u64 attr_version)
288{
289 struct inode *inode;
290 struct fuse_inode *fi;
291 struct fuse_conn *fc = get_fuse_conn_super(sb);
292
293 retry:
294 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
295 if (!inode)
296 return NULL;
297
298 if ((inode->i_state & I_NEW)) {
299 inode->i_flags |= S_NOATIME;
300 if (!fc->writeback_cache || !S_ISREG(attr->mode))
301 inode->i_flags |= S_NOCMTIME;
302 inode->i_generation = generation;
303 fuse_init_inode(inode, attr);
304 unlock_new_inode(inode);
305 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
306 /* Inode has changed type, any I/O on the old should fail */
307 make_bad_inode(inode);
308 iput(inode);
309 goto retry;
310 }
311
312 fi = get_fuse_inode(inode);
313 spin_lock(&fi->lock);
314 fi->nlookup++;
315 spin_unlock(&fi->lock);
316 fuse_change_attributes(inode, attr, attr_valid, attr_version);
317
318 return inode;
319}
320
321int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
322 loff_t offset, loff_t len)
323{
324 struct inode *inode;
325 pgoff_t pg_start;
326 pgoff_t pg_end;
327
328 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
329 if (!inode)
330 return -ENOENT;
331
332 fuse_invalidate_attr(inode);
333 forget_all_cached_acls(inode);
334 if (offset >= 0) {
335 pg_start = offset >> PAGE_SHIFT;
336 if (len <= 0)
337 pg_end = -1;
338 else
339 pg_end = (offset + len - 1) >> PAGE_SHIFT;
340 invalidate_inode_pages2_range(inode->i_mapping,
341 pg_start, pg_end);
342 }
343 iput(inode);
344 return 0;
345}
346
347bool fuse_lock_inode(struct inode *inode)
348{
349 bool locked = false;
350
351 if (!get_fuse_conn(inode)->parallel_dirops) {
352 mutex_lock(&get_fuse_inode(inode)->mutex);
353 locked = true;
354 }
355
356 return locked;
357}
358
359void fuse_unlock_inode(struct inode *inode, bool locked)
360{
361 if (locked)
362 mutex_unlock(&get_fuse_inode(inode)->mutex);
363}
364
365static void fuse_umount_begin(struct super_block *sb)
366{
367 struct fuse_conn *fc = get_fuse_conn_super(sb);
368
369 if (!fc->no_force_umount)
370 fuse_abort_conn(fc);
371}
372
373static void fuse_send_destroy(struct fuse_conn *fc)
374{
375 if (fc->conn_init) {
376 FUSE_ARGS(args);
377
378 args.opcode = FUSE_DESTROY;
379 args.force = true;
380 args.nocreds = true;
381 fuse_simple_request(fc, &args);
382 }
383}
384
385static void fuse_put_super(struct super_block *sb)
386{
387 struct fuse_conn *fc = get_fuse_conn_super(sb);
388
389 mutex_lock(&fuse_mutex);
390 list_del(&fc->entry);
391 fuse_ctl_remove_conn(fc);
392 mutex_unlock(&fuse_mutex);
393
394 fuse_conn_put(fc);
395}
396
397static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
398{
399 stbuf->f_type = FUSE_SUPER_MAGIC;
400 stbuf->f_bsize = attr->bsize;
401 stbuf->f_frsize = attr->frsize;
402 stbuf->f_blocks = attr->blocks;
403 stbuf->f_bfree = attr->bfree;
404 stbuf->f_bavail = attr->bavail;
405 stbuf->f_files = attr->files;
406 stbuf->f_ffree = attr->ffree;
407 stbuf->f_namelen = attr->namelen;
408 /* fsid is left zero */
409}
410
411static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
412{
413 struct super_block *sb = dentry->d_sb;
414 struct fuse_conn *fc = get_fuse_conn_super(sb);
415 FUSE_ARGS(args);
416 struct fuse_statfs_out outarg;
417 int err;
418
419 if (!fuse_allow_current_process(fc)) {
420 buf->f_type = FUSE_SUPER_MAGIC;
421 return 0;
422 }
423
424 memset(&outarg, 0, sizeof(outarg));
425 args.in_numargs = 0;
426 args.opcode = FUSE_STATFS;
427 args.nodeid = get_node_id(d_inode(dentry));
428 args.out_numargs = 1;
429 args.out_args[0].size = sizeof(outarg);
430 args.out_args[0].value = &outarg;
431 err = fuse_simple_request(fc, &args);
432 if (!err)
433 convert_fuse_statfs(buf, &outarg.st);
434 return err;
435}
436
437enum {
438 OPT_SOURCE,
439 OPT_SUBTYPE,
440 OPT_FD,
441 OPT_ROOTMODE,
442 OPT_USER_ID,
443 OPT_GROUP_ID,
444 OPT_DEFAULT_PERMISSIONS,
445 OPT_ALLOW_OTHER,
446 OPT_MAX_READ,
447 OPT_BLKSIZE,
448 OPT_ERR
449};
450
451static const struct fs_parameter_spec fuse_param_specs[] = {
452 fsparam_string ("source", OPT_SOURCE),
453 fsparam_u32 ("fd", OPT_FD),
454 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
455 fsparam_u32 ("user_id", OPT_USER_ID),
456 fsparam_u32 ("group_id", OPT_GROUP_ID),
457 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
458 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
459 fsparam_u32 ("max_read", OPT_MAX_READ),
460 fsparam_u32 ("blksize", OPT_BLKSIZE),
461 fsparam_string ("subtype", OPT_SUBTYPE),
462 {}
463};
464
465static const struct fs_parameter_description fuse_fs_parameters = {
466 .name = "fuse",
467 .specs = fuse_param_specs,
468};
469
470static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param)
471{
472 struct fs_parse_result result;
473 struct fuse_fs_context *ctx = fc->fs_private;
474 int opt;
475
476 opt = fs_parse(fc, &fuse_fs_parameters, param, &result);
477 if (opt < 0)
478 return opt;
479
480 switch (opt) {
481 case OPT_SOURCE:
482 if (fc->source)
483 return invalf(fc, "fuse: Multiple sources specified");
484 fc->source = param->string;
485 param->string = NULL;
486 break;
487
488 case OPT_SUBTYPE:
489 if (ctx->subtype)
490 return invalf(fc, "fuse: Multiple subtypes specified");
491 ctx->subtype = param->string;
492 param->string = NULL;
493 return 0;
494
495 case OPT_FD:
496 ctx->fd = result.uint_32;
497 ctx->fd_present = 1;
498 break;
499
500 case OPT_ROOTMODE:
501 if (!fuse_valid_type(result.uint_32))
502 return invalf(fc, "fuse: Invalid rootmode");
503 ctx->rootmode = result.uint_32;
504 ctx->rootmode_present = 1;
505 break;
506
507 case OPT_USER_ID:
508 ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
509 if (!uid_valid(ctx->user_id))
510 return invalf(fc, "fuse: Invalid user_id");
511 ctx->user_id_present = 1;
512 break;
513
514 case OPT_GROUP_ID:
515 ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
516 if (!gid_valid(ctx->group_id))
517 return invalf(fc, "fuse: Invalid group_id");
518 ctx->group_id_present = 1;
519 break;
520
521 case OPT_DEFAULT_PERMISSIONS:
522 ctx->default_permissions = 1;
523 break;
524
525 case OPT_ALLOW_OTHER:
526 ctx->allow_other = 1;
527 break;
528
529 case OPT_MAX_READ:
530 ctx->max_read = result.uint_32;
531 break;
532
533 case OPT_BLKSIZE:
534 if (!ctx->is_bdev)
535 return invalf(fc, "fuse: blksize only supported for fuseblk");
536 ctx->blksize = result.uint_32;
537 break;
538
539 default:
540 return -EINVAL;
541 }
542
543 return 0;
544}
545
546static void fuse_free_fc(struct fs_context *fc)
547{
548 struct fuse_fs_context *ctx = fc->fs_private;
549
550 if (ctx) {
551 kfree(ctx->subtype);
552 kfree(ctx);
553 }
554}
555
556static int fuse_show_options(struct seq_file *m, struct dentry *root)
557{
558 struct super_block *sb = root->d_sb;
559 struct fuse_conn *fc = get_fuse_conn_super(sb);
560
561 if (fc->no_mount_options)
562 return 0;
563
564 seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
565 seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
566 if (fc->default_permissions)
567 seq_puts(m, ",default_permissions");
568 if (fc->allow_other)
569 seq_puts(m, ",allow_other");
570 if (fc->max_read != ~0)
571 seq_printf(m, ",max_read=%u", fc->max_read);
572 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
573 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
574 return 0;
575}
576
577static void fuse_iqueue_init(struct fuse_iqueue *fiq,
578 const struct fuse_iqueue_ops *ops,
579 void *priv)
580{
581 memset(fiq, 0, sizeof(struct fuse_iqueue));
582 spin_lock_init(&fiq->lock);
583 init_waitqueue_head(&fiq->waitq);
584 INIT_LIST_HEAD(&fiq->pending);
585 INIT_LIST_HEAD(&fiq->interrupts);
586 fiq->forget_list_tail = &fiq->forget_list_head;
587 fiq->connected = 1;
588 fiq->ops = ops;
589 fiq->priv = priv;
590}
591
592static void fuse_pqueue_init(struct fuse_pqueue *fpq)
593{
594 unsigned int i;
595
596 spin_lock_init(&fpq->lock);
597 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
598 INIT_LIST_HEAD(&fpq->processing[i]);
599 INIT_LIST_HEAD(&fpq->io);
600 fpq->connected = 1;
601}
602
603void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
604 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
605{
606 memset(fc, 0, sizeof(*fc));
607 spin_lock_init(&fc->lock);
608 spin_lock_init(&fc->bg_lock);
609 init_rwsem(&fc->killsb);
610 refcount_set(&fc->count, 1);
611 atomic_set(&fc->dev_count, 1);
612 init_waitqueue_head(&fc->blocked_waitq);
613 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
614 INIT_LIST_HEAD(&fc->bg_queue);
615 INIT_LIST_HEAD(&fc->entry);
616 INIT_LIST_HEAD(&fc->devices);
617 atomic_set(&fc->num_waiting, 0);
618 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
619 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
620 atomic64_set(&fc->khctr, 0);
621 fc->polled_files = RB_ROOT;
622 fc->blocked = 0;
623 fc->initialized = 0;
624 fc->connected = 1;
625 atomic64_set(&fc->attr_version, 1);
626 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
627 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
628 fc->user_ns = get_user_ns(user_ns);
629 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
630}
631EXPORT_SYMBOL_GPL(fuse_conn_init);
632
633void fuse_conn_put(struct fuse_conn *fc)
634{
635 if (refcount_dec_and_test(&fc->count)) {
636 struct fuse_iqueue *fiq = &fc->iq;
637
638 if (fiq->ops->release)
639 fiq->ops->release(fiq);
640 put_pid_ns(fc->pid_ns);
641 put_user_ns(fc->user_ns);
642 fc->release(fc);
643 }
644}
645EXPORT_SYMBOL_GPL(fuse_conn_put);
646
647struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
648{
649 refcount_inc(&fc->count);
650 return fc;
651}
652EXPORT_SYMBOL_GPL(fuse_conn_get);
653
654static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
655{
656 struct fuse_attr attr;
657 memset(&attr, 0, sizeof(attr));
658
659 attr.mode = mode;
660 attr.ino = FUSE_ROOT_ID;
661 attr.nlink = 1;
662 return fuse_iget(sb, 1, 0, &attr, 0, 0);
663}
664
665struct fuse_inode_handle {
666 u64 nodeid;
667 u32 generation;
668};
669
670static struct dentry *fuse_get_dentry(struct super_block *sb,
671 struct fuse_inode_handle *handle)
672{
673 struct fuse_conn *fc = get_fuse_conn_super(sb);
674 struct inode *inode;
675 struct dentry *entry;
676 int err = -ESTALE;
677
678 if (handle->nodeid == 0)
679 goto out_err;
680
681 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
682 if (!inode) {
683 struct fuse_entry_out outarg;
684 const struct qstr name = QSTR_INIT(".", 1);
685
686 if (!fc->export_support)
687 goto out_err;
688
689 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
690 &inode);
691 if (err && err != -ENOENT)
692 goto out_err;
693 if (err || !inode) {
694 err = -ESTALE;
695 goto out_err;
696 }
697 err = -EIO;
698 if (get_node_id(inode) != handle->nodeid)
699 goto out_iput;
700 }
701 err = -ESTALE;
702 if (inode->i_generation != handle->generation)
703 goto out_iput;
704
705 entry = d_obtain_alias(inode);
706 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
707 fuse_invalidate_entry_cache(entry);
708
709 return entry;
710
711 out_iput:
712 iput(inode);
713 out_err:
714 return ERR_PTR(err);
715}
716
717static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
718 struct inode *parent)
719{
720 int len = parent ? 6 : 3;
721 u64 nodeid;
722 u32 generation;
723
724 if (*max_len < len) {
725 *max_len = len;
726 return FILEID_INVALID;
727 }
728
729 nodeid = get_fuse_inode(inode)->nodeid;
730 generation = inode->i_generation;
731
732 fh[0] = (u32)(nodeid >> 32);
733 fh[1] = (u32)(nodeid & 0xffffffff);
734 fh[2] = generation;
735
736 if (parent) {
737 nodeid = get_fuse_inode(parent)->nodeid;
738 generation = parent->i_generation;
739
740 fh[3] = (u32)(nodeid >> 32);
741 fh[4] = (u32)(nodeid & 0xffffffff);
742 fh[5] = generation;
743 }
744
745 *max_len = len;
746 return parent ? 0x82 : 0x81;
747}
748
749static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
750 struct fid *fid, int fh_len, int fh_type)
751{
752 struct fuse_inode_handle handle;
753
754 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
755 return NULL;
756
757 handle.nodeid = (u64) fid->raw[0] << 32;
758 handle.nodeid |= (u64) fid->raw[1];
759 handle.generation = fid->raw[2];
760 return fuse_get_dentry(sb, &handle);
761}
762
763static struct dentry *fuse_fh_to_parent(struct super_block *sb,
764 struct fid *fid, int fh_len, int fh_type)
765{
766 struct fuse_inode_handle parent;
767
768 if (fh_type != 0x82 || fh_len < 6)
769 return NULL;
770
771 parent.nodeid = (u64) fid->raw[3] << 32;
772 parent.nodeid |= (u64) fid->raw[4];
773 parent.generation = fid->raw[5];
774 return fuse_get_dentry(sb, &parent);
775}
776
777static struct dentry *fuse_get_parent(struct dentry *child)
778{
779 struct inode *child_inode = d_inode(child);
780 struct fuse_conn *fc = get_fuse_conn(child_inode);
781 struct inode *inode;
782 struct dentry *parent;
783 struct fuse_entry_out outarg;
784 const struct qstr name = QSTR_INIT("..", 2);
785 int err;
786
787 if (!fc->export_support)
788 return ERR_PTR(-ESTALE);
789
790 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
791 &name, &outarg, &inode);
792 if (err) {
793 if (err == -ENOENT)
794 return ERR_PTR(-ESTALE);
795 return ERR_PTR(err);
796 }
797
798 parent = d_obtain_alias(inode);
799 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
800 fuse_invalidate_entry_cache(parent);
801
802 return parent;
803}
804
805static const struct export_operations fuse_export_operations = {
806 .fh_to_dentry = fuse_fh_to_dentry,
807 .fh_to_parent = fuse_fh_to_parent,
808 .encode_fh = fuse_encode_fh,
809 .get_parent = fuse_get_parent,
810};
811
812static const struct super_operations fuse_super_operations = {
813 .alloc_inode = fuse_alloc_inode,
814 .free_inode = fuse_free_inode,
815 .evict_inode = fuse_evict_inode,
816 .write_inode = fuse_write_inode,
817 .drop_inode = generic_delete_inode,
818 .remount_fs = fuse_remount_fs,
819 .put_super = fuse_put_super,
820 .umount_begin = fuse_umount_begin,
821 .statfs = fuse_statfs,
822 .show_options = fuse_show_options,
823};
824
825static void sanitize_global_limit(unsigned *limit)
826{
827 /*
828 * The default maximum number of async requests is calculated to consume
829 * 1/2^13 of the total memory, assuming 392 bytes per request.
830 */
831 if (*limit == 0)
832 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
833
834 if (*limit >= 1 << 16)
835 *limit = (1 << 16) - 1;
836}
837
838static int set_global_limit(const char *val, const struct kernel_param *kp)
839{
840 int rv;
841
842 rv = param_set_uint(val, kp);
843 if (rv)
844 return rv;
845
846 sanitize_global_limit((unsigned *)kp->arg);
847
848 return 0;
849}
850
851static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
852{
853 int cap_sys_admin = capable(CAP_SYS_ADMIN);
854
855 if (arg->minor < 13)
856 return;
857
858 sanitize_global_limit(&max_user_bgreq);
859 sanitize_global_limit(&max_user_congthresh);
860
861 spin_lock(&fc->bg_lock);
862 if (arg->max_background) {
863 fc->max_background = arg->max_background;
864
865 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
866 fc->max_background = max_user_bgreq;
867 }
868 if (arg->congestion_threshold) {
869 fc->congestion_threshold = arg->congestion_threshold;
870
871 if (!cap_sys_admin &&
872 fc->congestion_threshold > max_user_congthresh)
873 fc->congestion_threshold = max_user_congthresh;
874 }
875 spin_unlock(&fc->bg_lock);
876}
877
878struct fuse_init_args {
879 struct fuse_args args;
880 struct fuse_init_in in;
881 struct fuse_init_out out;
882};
883
884static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args,
885 int error)
886{
887 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
888 struct fuse_init_out *arg = &ia->out;
889
890 if (error || arg->major != FUSE_KERNEL_VERSION)
891 fc->conn_error = 1;
892 else {
893 unsigned long ra_pages;
894
895 process_init_limits(fc, arg);
896
897 if (arg->minor >= 6) {
898 ra_pages = arg->max_readahead / PAGE_SIZE;
899 if (arg->flags & FUSE_ASYNC_READ)
900 fc->async_read = 1;
901 if (!(arg->flags & FUSE_POSIX_LOCKS))
902 fc->no_lock = 1;
903 if (arg->minor >= 17) {
904 if (!(arg->flags & FUSE_FLOCK_LOCKS))
905 fc->no_flock = 1;
906 } else {
907 if (!(arg->flags & FUSE_POSIX_LOCKS))
908 fc->no_flock = 1;
909 }
910 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
911 fc->atomic_o_trunc = 1;
912 if (arg->minor >= 9) {
913 /* LOOKUP has dependency on proto version */
914 if (arg->flags & FUSE_EXPORT_SUPPORT)
915 fc->export_support = 1;
916 }
917 if (arg->flags & FUSE_BIG_WRITES)
918 fc->big_writes = 1;
919 if (arg->flags & FUSE_DONT_MASK)
920 fc->dont_mask = 1;
921 if (arg->flags & FUSE_AUTO_INVAL_DATA)
922 fc->auto_inval_data = 1;
923 else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
924 fc->explicit_inval_data = 1;
925 if (arg->flags & FUSE_DO_READDIRPLUS) {
926 fc->do_readdirplus = 1;
927 if (arg->flags & FUSE_READDIRPLUS_AUTO)
928 fc->readdirplus_auto = 1;
929 }
930 if (arg->flags & FUSE_ASYNC_DIO)
931 fc->async_dio = 1;
932 if (arg->flags & FUSE_WRITEBACK_CACHE)
933 fc->writeback_cache = 1;
934 if (arg->flags & FUSE_PARALLEL_DIROPS)
935 fc->parallel_dirops = 1;
936 if (arg->flags & FUSE_HANDLE_KILLPRIV)
937 fc->handle_killpriv = 1;
938 if (arg->time_gran && arg->time_gran <= 1000000000)
939 fc->sb->s_time_gran = arg->time_gran;
940 if ((arg->flags & FUSE_POSIX_ACL)) {
941 fc->default_permissions = 1;
942 fc->posix_acl = 1;
943 fc->sb->s_xattr = fuse_acl_xattr_handlers;
944 }
945 if (arg->flags & FUSE_CACHE_SYMLINKS)
946 fc->cache_symlinks = 1;
947 if (arg->flags & FUSE_ABORT_ERROR)
948 fc->abort_err = 1;
949 if (arg->flags & FUSE_MAX_PAGES) {
950 fc->max_pages =
951 min_t(unsigned int, FUSE_MAX_MAX_PAGES,
952 max_t(unsigned int, arg->max_pages, 1));
953 }
954 } else {
955 ra_pages = fc->max_read / PAGE_SIZE;
956 fc->no_lock = 1;
957 fc->no_flock = 1;
958 }
959
960 fc->sb->s_bdi->ra_pages =
961 min(fc->sb->s_bdi->ra_pages, ra_pages);
962 fc->minor = arg->minor;
963 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
964 fc->max_write = max_t(unsigned, 4096, fc->max_write);
965 fc->conn_init = 1;
966 }
967 kfree(ia);
968
969 fuse_set_initialized(fc);
970 wake_up_all(&fc->blocked_waitq);
971}
972
973void fuse_send_init(struct fuse_conn *fc)
974{
975 struct fuse_init_args *ia;
976
977 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
978
979 ia->in.major = FUSE_KERNEL_VERSION;
980 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
981 ia->in.max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
982 ia->in.flags |=
983 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
984 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
985 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
986 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
987 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
988 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
989 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
990 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
991 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
992 ia->args.opcode = FUSE_INIT;
993 ia->args.in_numargs = 1;
994 ia->args.in_args[0].size = sizeof(ia->in);
995 ia->args.in_args[0].value = &ia->in;
996 ia->args.out_numargs = 1;
997 /* Variable length argument used for backward compatibility
998 with interface version < 7.5. Rest of init_out is zeroed
999 by do_get_request(), so a short reply is not a problem */
1000 ia->args.out_argvar = 1;
1001 ia->args.out_args[0].size = sizeof(ia->out);
1002 ia->args.out_args[0].value = &ia->out;
1003 ia->args.force = true;
1004 ia->args.nocreds = true;
1005 ia->args.end = process_init_reply;
1006
1007 if (fuse_simple_background(fc, &ia->args, GFP_KERNEL) != 0)
1008 process_init_reply(fc, &ia->args, -ENOTCONN);
1009}
1010EXPORT_SYMBOL_GPL(fuse_send_init);
1011
1012void fuse_free_conn(struct fuse_conn *fc)
1013{
1014 WARN_ON(!list_empty(&fc->devices));
1015 kfree_rcu(fc, rcu);
1016}
1017EXPORT_SYMBOL_GPL(fuse_free_conn);
1018
1019static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1020{
1021 int err;
1022 char *suffix = "";
1023
1024 if (sb->s_bdev) {
1025 suffix = "-fuseblk";
1026 /*
1027 * sb->s_bdi points to blkdev's bdi however we want to redirect
1028 * it to our private bdi...
1029 */
1030 bdi_put(sb->s_bdi);
1031 sb->s_bdi = &noop_backing_dev_info;
1032 }
1033 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1034 MINOR(fc->dev), suffix);
1035 if (err)
1036 return err;
1037
1038 sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
1039 /* fuse does it's own writeback accounting */
1040 sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1041
1042 /*
1043 * For a single fuse filesystem use max 1% of dirty +
1044 * writeback threshold.
1045 *
1046 * This gives about 1M of write buffer for memory maps on a
1047 * machine with 1G and 10% dirty_ratio, which should be more
1048 * than enough.
1049 *
1050 * Privileged users can raise it by writing to
1051 *
1052 * /sys/class/bdi/<bdi>/max_ratio
1053 */
1054 bdi_set_max_ratio(sb->s_bdi, 1);
1055
1056 return 0;
1057}
1058
1059struct fuse_dev *fuse_dev_alloc(void)
1060{
1061 struct fuse_dev *fud;
1062 struct list_head *pq;
1063
1064 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1065 if (!fud)
1066 return NULL;
1067
1068 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1069 if (!pq) {
1070 kfree(fud);
1071 return NULL;
1072 }
1073
1074 fud->pq.processing = pq;
1075 fuse_pqueue_init(&fud->pq);
1076
1077 return fud;
1078}
1079EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1080
1081void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1082{
1083 fud->fc = fuse_conn_get(fc);
1084 spin_lock(&fc->lock);
1085 list_add_tail(&fud->entry, &fc->devices);
1086 spin_unlock(&fc->lock);
1087}
1088EXPORT_SYMBOL_GPL(fuse_dev_install);
1089
1090struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1091{
1092 struct fuse_dev *fud;
1093
1094 fud = fuse_dev_alloc();
1095 if (!fud)
1096 return NULL;
1097
1098 fuse_dev_install(fud, fc);
1099 return fud;
1100}
1101EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1102
1103void fuse_dev_free(struct fuse_dev *fud)
1104{
1105 struct fuse_conn *fc = fud->fc;
1106
1107 if (fc) {
1108 spin_lock(&fc->lock);
1109 list_del(&fud->entry);
1110 spin_unlock(&fc->lock);
1111
1112 fuse_conn_put(fc);
1113 }
1114 kfree(fud->pq.processing);
1115 kfree(fud);
1116}
1117EXPORT_SYMBOL_GPL(fuse_dev_free);
1118
1119int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1120{
1121 struct fuse_dev *fud;
1122 struct fuse_conn *fc = get_fuse_conn_super(sb);
1123 struct inode *root;
1124 struct dentry *root_dentry;
1125 int err;
1126
1127 err = -EINVAL;
1128 if (sb->s_flags & SB_MANDLOCK)
1129 goto err;
1130
1131 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1132
1133 if (ctx->is_bdev) {
1134#ifdef CONFIG_BLOCK
1135 err = -EINVAL;
1136 if (!sb_set_blocksize(sb, ctx->blksize))
1137 goto err;
1138#endif
1139 } else {
1140 sb->s_blocksize = PAGE_SIZE;
1141 sb->s_blocksize_bits = PAGE_SHIFT;
1142 }
1143
1144 sb->s_subtype = ctx->subtype;
1145 ctx->subtype = NULL;
1146 sb->s_magic = FUSE_SUPER_MAGIC;
1147 sb->s_op = &fuse_super_operations;
1148 sb->s_xattr = fuse_xattr_handlers;
1149 sb->s_maxbytes = MAX_LFS_FILESIZE;
1150 sb->s_time_gran = 1;
1151 sb->s_export_op = &fuse_export_operations;
1152 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1153 if (sb->s_user_ns != &init_user_ns)
1154 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1155
1156 /*
1157 * If we are not in the initial user namespace posix
1158 * acls must be translated.
1159 */
1160 if (sb->s_user_ns != &init_user_ns)
1161 sb->s_xattr = fuse_no_acl_xattr_handlers;
1162
1163 fud = fuse_dev_alloc_install(fc);
1164 if (!fud)
1165 goto err;
1166
1167 fc->dev = sb->s_dev;
1168 fc->sb = sb;
1169 err = fuse_bdi_init(fc, sb);
1170 if (err)
1171 goto err_dev_free;
1172
1173 /* Handle umasking inside the fuse code */
1174 if (sb->s_flags & SB_POSIXACL)
1175 fc->dont_mask = 1;
1176 sb->s_flags |= SB_POSIXACL;
1177
1178 fc->default_permissions = ctx->default_permissions;
1179 fc->allow_other = ctx->allow_other;
1180 fc->user_id = ctx->user_id;
1181 fc->group_id = ctx->group_id;
1182 fc->max_read = max_t(unsigned, 4096, ctx->max_read);
1183 fc->destroy = ctx->destroy;
1184 fc->no_control = ctx->no_control;
1185 fc->no_force_umount = ctx->no_force_umount;
1186 fc->no_mount_options = ctx->no_mount_options;
1187
1188 err = -ENOMEM;
1189 root = fuse_get_root_inode(sb, ctx->rootmode);
1190 sb->s_d_op = &fuse_root_dentry_operations;
1191 root_dentry = d_make_root(root);
1192 if (!root_dentry)
1193 goto err_dev_free;
1194 /* Root dentry doesn't have .d_revalidate */
1195 sb->s_d_op = &fuse_dentry_operations;
1196
1197 mutex_lock(&fuse_mutex);
1198 err = -EINVAL;
1199 if (*ctx->fudptr)
1200 goto err_unlock;
1201
1202 err = fuse_ctl_add_conn(fc);
1203 if (err)
1204 goto err_unlock;
1205
1206 list_add_tail(&fc->entry, &fuse_conn_list);
1207 sb->s_root = root_dentry;
1208 *ctx->fudptr = fud;
1209 mutex_unlock(&fuse_mutex);
1210 return 0;
1211
1212 err_unlock:
1213 mutex_unlock(&fuse_mutex);
1214 dput(root_dentry);
1215 err_dev_free:
1216 fuse_dev_free(fud);
1217 err:
1218 return err;
1219}
1220EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1221
1222static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1223{
1224 struct fuse_fs_context *ctx = fsc->fs_private;
1225 struct file *file;
1226 int err;
1227 struct fuse_conn *fc;
1228
1229 err = -EINVAL;
1230 file = fget(ctx->fd);
1231 if (!file)
1232 goto err;
1233
1234 /*
1235 * Require mount to happen from the same user namespace which
1236 * opened /dev/fuse to prevent potential attacks.
1237 */
1238 if ((file->f_op != &fuse_dev_operations) ||
1239 (file->f_cred->user_ns != sb->s_user_ns))
1240 goto err_fput;
1241 ctx->fudptr = &file->private_data;
1242
1243 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1244 err = -ENOMEM;
1245 if (!fc)
1246 goto err_fput;
1247
1248 fuse_conn_init(fc, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
1249 fc->release = fuse_free_conn;
1250 sb->s_fs_info = fc;
1251
1252 err = fuse_fill_super_common(sb, ctx);
1253 if (err)
1254 goto err_put_conn;
1255 /*
1256 * atomic_dec_and_test() in fput() provides the necessary
1257 * memory barrier for file->private_data to be visible on all
1258 * CPUs after this
1259 */
1260 fput(file);
1261 fuse_send_init(get_fuse_conn_super(sb));
1262 return 0;
1263
1264 err_put_conn:
1265 fuse_conn_put(fc);
1266 sb->s_fs_info = NULL;
1267 err_fput:
1268 fput(file);
1269 err:
1270 return err;
1271}
1272
1273static int fuse_get_tree(struct fs_context *fc)
1274{
1275 struct fuse_fs_context *ctx = fc->fs_private;
1276
1277 if (!ctx->fd_present || !ctx->rootmode_present ||
1278 !ctx->user_id_present || !ctx->group_id_present)
1279 return -EINVAL;
1280
1281#ifdef CONFIG_BLOCK
1282 if (ctx->is_bdev)
1283 return get_tree_bdev(fc, fuse_fill_super);
1284#endif
1285
1286 return get_tree_nodev(fc, fuse_fill_super);
1287}
1288
1289static const struct fs_context_operations fuse_context_ops = {
1290 .free = fuse_free_fc,
1291 .parse_param = fuse_parse_param,
1292 .get_tree = fuse_get_tree,
1293};
1294
1295/*
1296 * Set up the filesystem mount context.
1297 */
1298static int fuse_init_fs_context(struct fs_context *fc)
1299{
1300 struct fuse_fs_context *ctx;
1301
1302 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1303 if (!ctx)
1304 return -ENOMEM;
1305
1306 ctx->max_read = ~0;
1307 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1308
1309#ifdef CONFIG_BLOCK
1310 if (fc->fs_type == &fuseblk_fs_type) {
1311 ctx->is_bdev = true;
1312 ctx->destroy = true;
1313 }
1314#endif
1315
1316 fc->fs_private = ctx;
1317 fc->ops = &fuse_context_ops;
1318 return 0;
1319}
1320
1321static void fuse_sb_destroy(struct super_block *sb)
1322{
1323 struct fuse_conn *fc = get_fuse_conn_super(sb);
1324
1325 if (fc) {
1326 if (fc->destroy)
1327 fuse_send_destroy(fc);
1328
1329 fuse_abort_conn(fc);
1330 fuse_wait_aborted(fc);
1331
1332 down_write(&fc->killsb);
1333 fc->sb = NULL;
1334 up_write(&fc->killsb);
1335 }
1336}
1337
1338void fuse_kill_sb_anon(struct super_block *sb)
1339{
1340 fuse_sb_destroy(sb);
1341 kill_anon_super(sb);
1342}
1343EXPORT_SYMBOL_GPL(fuse_kill_sb_anon);
1344
1345static struct file_system_type fuse_fs_type = {
1346 .owner = THIS_MODULE,
1347 .name = "fuse",
1348 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1349 .init_fs_context = fuse_init_fs_context,
1350 .parameters = &fuse_fs_parameters,
1351 .kill_sb = fuse_kill_sb_anon,
1352};
1353MODULE_ALIAS_FS("fuse");
1354
1355#ifdef CONFIG_BLOCK
1356static void fuse_kill_sb_blk(struct super_block *sb)
1357{
1358 fuse_sb_destroy(sb);
1359 kill_block_super(sb);
1360}
1361
1362static struct file_system_type fuseblk_fs_type = {
1363 .owner = THIS_MODULE,
1364 .name = "fuseblk",
1365 .init_fs_context = fuse_init_fs_context,
1366 .parameters = &fuse_fs_parameters,
1367 .kill_sb = fuse_kill_sb_blk,
1368 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1369};
1370MODULE_ALIAS_FS("fuseblk");
1371
1372static inline int register_fuseblk(void)
1373{
1374 return register_filesystem(&fuseblk_fs_type);
1375}
1376
1377static inline void unregister_fuseblk(void)
1378{
1379 unregister_filesystem(&fuseblk_fs_type);
1380}
1381#else
1382static inline int register_fuseblk(void)
1383{
1384 return 0;
1385}
1386
1387static inline void unregister_fuseblk(void)
1388{
1389}
1390#endif
1391
1392static void fuse_inode_init_once(void *foo)
1393{
1394 struct inode *inode = foo;
1395
1396 inode_init_once(inode);
1397}
1398
1399static int __init fuse_fs_init(void)
1400{
1401 int err;
1402
1403 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1404 sizeof(struct fuse_inode), 0,
1405 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1406 fuse_inode_init_once);
1407 err = -ENOMEM;
1408 if (!fuse_inode_cachep)
1409 goto out;
1410
1411 err = register_fuseblk();
1412 if (err)
1413 goto out2;
1414
1415 err = register_filesystem(&fuse_fs_type);
1416 if (err)
1417 goto out3;
1418
1419 return 0;
1420
1421 out3:
1422 unregister_fuseblk();
1423 out2:
1424 kmem_cache_destroy(fuse_inode_cachep);
1425 out:
1426 return err;
1427}
1428
1429static void fuse_fs_cleanup(void)
1430{
1431 unregister_filesystem(&fuse_fs_type);
1432 unregister_fuseblk();
1433
1434 /*
1435 * Make sure all delayed rcu free inodes are flushed before we
1436 * destroy cache.
1437 */
1438 rcu_barrier();
1439 kmem_cache_destroy(fuse_inode_cachep);
1440}
1441
1442static struct kobject *fuse_kobj;
1443
1444static int fuse_sysfs_init(void)
1445{
1446 int err;
1447
1448 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1449 if (!fuse_kobj) {
1450 err = -ENOMEM;
1451 goto out_err;
1452 }
1453
1454 err = sysfs_create_mount_point(fuse_kobj, "connections");
1455 if (err)
1456 goto out_fuse_unregister;
1457
1458 return 0;
1459
1460 out_fuse_unregister:
1461 kobject_put(fuse_kobj);
1462 out_err:
1463 return err;
1464}
1465
1466static void fuse_sysfs_cleanup(void)
1467{
1468 sysfs_remove_mount_point(fuse_kobj, "connections");
1469 kobject_put(fuse_kobj);
1470}
1471
1472static int __init fuse_init(void)
1473{
1474 int res;
1475
1476 pr_info("init (API version %i.%i)\n",
1477 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1478
1479 INIT_LIST_HEAD(&fuse_conn_list);
1480 res = fuse_fs_init();
1481 if (res)
1482 goto err;
1483
1484 res = fuse_dev_init();
1485 if (res)
1486 goto err_fs_cleanup;
1487
1488 res = fuse_sysfs_init();
1489 if (res)
1490 goto err_dev_cleanup;
1491
1492 res = fuse_ctl_init();
1493 if (res)
1494 goto err_sysfs_cleanup;
1495
1496 sanitize_global_limit(&max_user_bgreq);
1497 sanitize_global_limit(&max_user_congthresh);
1498
1499 return 0;
1500
1501 err_sysfs_cleanup:
1502 fuse_sysfs_cleanup();
1503 err_dev_cleanup:
1504 fuse_dev_cleanup();
1505 err_fs_cleanup:
1506 fuse_fs_cleanup();
1507 err:
1508 return res;
1509}
1510
1511static void __exit fuse_exit(void)
1512{
1513 pr_debug("exit\n");
1514
1515 fuse_ctl_cleanup();
1516 fuse_sysfs_cleanup();
1517 fuse_fs_cleanup();
1518 fuse_dev_cleanup();
1519}
1520
1521module_init(fuse_init);
1522module_exit(fuse_exit);