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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 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
107static 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
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 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
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
143void 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
180void 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
205static 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
225int 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
234static 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
241struct 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
276int 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
301static void fuse_umount_begin(struct super_block *sb)
302{
303 fuse_abort_conn(get_fuse_conn_super(sb));
304}
305
306static 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
318static void fuse_bdi_destroy(struct fuse_conn *fc)
319{
320 if (fc->bdi_initialized)
321 bdi_destroy(&fc->bdi);
322}
323
324void 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}
341EXPORT_SYMBOL_GPL(fuse_conn_kill);
342
343static 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
352static 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
366static 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
399enum {
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
411static 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
423static 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
501static 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
519void 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}
546EXPORT_SYMBOL_GPL(fuse_conn_init);
547
548void 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}
557EXPORT_SYMBOL_GPL(fuse_conn_put);
558
559struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
560{
561 atomic_inc(&fc->count);
562 return fc;
563}
564EXPORT_SYMBOL_GPL(fuse_conn_get);
565
566static 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
577struct fuse_inode_handle {
578 u64 nodeid;
579 u32 generation;
580};
581
582static 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
631static 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
670static 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
684static 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
698static 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
728static 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
735static 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
747static 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
757static 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
770static 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
795static 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->minor >= 17) {
813 if (!(arg->flags & FUSE_FLOCK_LOCKS))
814 fc->no_flock = 1;
815 } else {
816 if (!(arg->flags & FUSE_POSIX_LOCKS))
817 fc->no_flock = 1;
818 }
819 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
820 fc->atomic_o_trunc = 1;
821 if (arg->minor >= 9) {
822 /* LOOKUP has dependency on proto version */
823 if (arg->flags & FUSE_EXPORT_SUPPORT)
824 fc->export_support = 1;
825 }
826 if (arg->flags & FUSE_BIG_WRITES)
827 fc->big_writes = 1;
828 if (arg->flags & FUSE_DONT_MASK)
829 fc->dont_mask = 1;
830 } else {
831 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
832 fc->no_lock = 1;
833 fc->no_flock = 1;
834 }
835
836 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
837 fc->minor = arg->minor;
838 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
839 fc->max_write = max_t(unsigned, 4096, fc->max_write);
840 fc->conn_init = 1;
841 }
842 fc->blocked = 0;
843 wake_up_all(&fc->blocked_waitq);
844}
845
846static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
847{
848 struct fuse_init_in *arg = &req->misc.init_in;
849
850 arg->major = FUSE_KERNEL_VERSION;
851 arg->minor = FUSE_KERNEL_MINOR_VERSION;
852 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
853 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
854 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
855 FUSE_FLOCK_LOCKS;
856 req->in.h.opcode = FUSE_INIT;
857 req->in.numargs = 1;
858 req->in.args[0].size = sizeof(*arg);
859 req->in.args[0].value = arg;
860 req->out.numargs = 1;
861 /* Variable length argument used for backward compatibility
862 with interface version < 7.5. Rest of init_out is zeroed
863 by do_get_request(), so a short reply is not a problem */
864 req->out.argvar = 1;
865 req->out.args[0].size = sizeof(struct fuse_init_out);
866 req->out.args[0].value = &req->misc.init_out;
867 req->end = process_init_reply;
868 fuse_request_send_background(fc, req);
869}
870
871static void fuse_free_conn(struct fuse_conn *fc)
872{
873 kfree(fc);
874}
875
876static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
877{
878 int err;
879
880 fc->bdi.name = "fuse";
881 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
882 /* fuse does it's own writeback accounting */
883 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
884
885 err = bdi_init(&fc->bdi);
886 if (err)
887 return err;
888
889 fc->bdi_initialized = 1;
890
891 if (sb->s_bdev) {
892 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
893 MAJOR(fc->dev), MINOR(fc->dev));
894 } else {
895 err = bdi_register_dev(&fc->bdi, fc->dev);
896 }
897
898 if (err)
899 return err;
900
901 /*
902 * For a single fuse filesystem use max 1% of dirty +
903 * writeback threshold.
904 *
905 * This gives about 1M of write buffer for memory maps on a
906 * machine with 1G and 10% dirty_ratio, which should be more
907 * than enough.
908 *
909 * Privileged users can raise it by writing to
910 *
911 * /sys/class/bdi/<bdi>/max_ratio
912 */
913 bdi_set_max_ratio(&fc->bdi, 1);
914
915 return 0;
916}
917
918static int fuse_fill_super(struct super_block *sb, void *data, int silent)
919{
920 struct fuse_conn *fc;
921 struct inode *root;
922 struct fuse_mount_data d;
923 struct file *file;
924 struct dentry *root_dentry;
925 struct fuse_req *init_req;
926 int err;
927 int is_bdev = sb->s_bdev != NULL;
928
929 err = -EINVAL;
930 if (sb->s_flags & MS_MANDLOCK)
931 goto err;
932
933 sb->s_flags &= ~MS_NOSEC;
934
935 if (!parse_fuse_opt((char *) data, &d, is_bdev))
936 goto err;
937
938 if (is_bdev) {
939#ifdef CONFIG_BLOCK
940 err = -EINVAL;
941 if (!sb_set_blocksize(sb, d.blksize))
942 goto err;
943#endif
944 } else {
945 sb->s_blocksize = PAGE_CACHE_SIZE;
946 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
947 }
948 sb->s_magic = FUSE_SUPER_MAGIC;
949 sb->s_op = &fuse_super_operations;
950 sb->s_maxbytes = MAX_LFS_FILESIZE;
951 sb->s_export_op = &fuse_export_operations;
952
953 file = fget(d.fd);
954 err = -EINVAL;
955 if (!file)
956 goto err;
957
958 if (file->f_op != &fuse_dev_operations)
959 goto err_fput;
960
961 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
962 err = -ENOMEM;
963 if (!fc)
964 goto err_fput;
965
966 fuse_conn_init(fc);
967
968 fc->dev = sb->s_dev;
969 fc->sb = sb;
970 err = fuse_bdi_init(fc, sb);
971 if (err)
972 goto err_put_conn;
973
974 sb->s_bdi = &fc->bdi;
975
976 /* Handle umasking inside the fuse code */
977 if (sb->s_flags & MS_POSIXACL)
978 fc->dont_mask = 1;
979 sb->s_flags |= MS_POSIXACL;
980
981 fc->release = fuse_free_conn;
982 fc->flags = d.flags;
983 fc->user_id = d.user_id;
984 fc->group_id = d.group_id;
985 fc->max_read = max_t(unsigned, 4096, d.max_read);
986
987 /* Used by get_root_inode() */
988 sb->s_fs_info = fc;
989
990 err = -ENOMEM;
991 root = fuse_get_root_inode(sb, d.rootmode);
992 if (!root)
993 goto err_put_conn;
994
995 root_dentry = d_alloc_root(root);
996 if (!root_dentry) {
997 iput(root);
998 goto err_put_conn;
999 }
1000 /* only now - we want root dentry with NULL ->d_op */
1001 sb->s_d_op = &fuse_dentry_operations;
1002
1003 init_req = fuse_request_alloc();
1004 if (!init_req)
1005 goto err_put_root;
1006
1007 if (is_bdev) {
1008 fc->destroy_req = fuse_request_alloc();
1009 if (!fc->destroy_req)
1010 goto err_free_init_req;
1011 }
1012
1013 mutex_lock(&fuse_mutex);
1014 err = -EINVAL;
1015 if (file->private_data)
1016 goto err_unlock;
1017
1018 err = fuse_ctl_add_conn(fc);
1019 if (err)
1020 goto err_unlock;
1021
1022 list_add_tail(&fc->entry, &fuse_conn_list);
1023 sb->s_root = root_dentry;
1024 fc->connected = 1;
1025 file->private_data = fuse_conn_get(fc);
1026 mutex_unlock(&fuse_mutex);
1027 /*
1028 * atomic_dec_and_test() in fput() provides the necessary
1029 * memory barrier for file->private_data to be visible on all
1030 * CPUs after this
1031 */
1032 fput(file);
1033
1034 fuse_send_init(fc, init_req);
1035
1036 return 0;
1037
1038 err_unlock:
1039 mutex_unlock(&fuse_mutex);
1040 err_free_init_req:
1041 fuse_request_free(init_req);
1042 err_put_root:
1043 dput(root_dentry);
1044 err_put_conn:
1045 fuse_bdi_destroy(fc);
1046 fuse_conn_put(fc);
1047 err_fput:
1048 fput(file);
1049 err:
1050 return err;
1051}
1052
1053static struct dentry *fuse_mount(struct file_system_type *fs_type,
1054 int flags, const char *dev_name,
1055 void *raw_data)
1056{
1057 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1058}
1059
1060static void fuse_kill_sb_anon(struct super_block *sb)
1061{
1062 struct fuse_conn *fc = get_fuse_conn_super(sb);
1063
1064 if (fc) {
1065 down_write(&fc->killsb);
1066 fc->sb = NULL;
1067 up_write(&fc->killsb);
1068 }
1069
1070 kill_anon_super(sb);
1071}
1072
1073static struct file_system_type fuse_fs_type = {
1074 .owner = THIS_MODULE,
1075 .name = "fuse",
1076 .fs_flags = FS_HAS_SUBTYPE,
1077 .mount = fuse_mount,
1078 .kill_sb = fuse_kill_sb_anon,
1079};
1080
1081#ifdef CONFIG_BLOCK
1082static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1083 int flags, const char *dev_name,
1084 void *raw_data)
1085{
1086 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1087}
1088
1089static void fuse_kill_sb_blk(struct super_block *sb)
1090{
1091 struct fuse_conn *fc = get_fuse_conn_super(sb);
1092
1093 if (fc) {
1094 down_write(&fc->killsb);
1095 fc->sb = NULL;
1096 up_write(&fc->killsb);
1097 }
1098
1099 kill_block_super(sb);
1100}
1101
1102static struct file_system_type fuseblk_fs_type = {
1103 .owner = THIS_MODULE,
1104 .name = "fuseblk",
1105 .mount = fuse_mount_blk,
1106 .kill_sb = fuse_kill_sb_blk,
1107 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1108};
1109
1110static inline int register_fuseblk(void)
1111{
1112 return register_filesystem(&fuseblk_fs_type);
1113}
1114
1115static inline void unregister_fuseblk(void)
1116{
1117 unregister_filesystem(&fuseblk_fs_type);
1118}
1119#else
1120static inline int register_fuseblk(void)
1121{
1122 return 0;
1123}
1124
1125static inline void unregister_fuseblk(void)
1126{
1127}
1128#endif
1129
1130static void fuse_inode_init_once(void *foo)
1131{
1132 struct inode *inode = foo;
1133
1134 inode_init_once(inode);
1135}
1136
1137static int __init fuse_fs_init(void)
1138{
1139 int err;
1140
1141 err = register_filesystem(&fuse_fs_type);
1142 if (err)
1143 goto out;
1144
1145 err = register_fuseblk();
1146 if (err)
1147 goto out_unreg;
1148
1149 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1150 sizeof(struct fuse_inode),
1151 0, SLAB_HWCACHE_ALIGN,
1152 fuse_inode_init_once);
1153 err = -ENOMEM;
1154 if (!fuse_inode_cachep)
1155 goto out_unreg2;
1156
1157 return 0;
1158
1159 out_unreg2:
1160 unregister_fuseblk();
1161 out_unreg:
1162 unregister_filesystem(&fuse_fs_type);
1163 out:
1164 return err;
1165}
1166
1167static void fuse_fs_cleanup(void)
1168{
1169 unregister_filesystem(&fuse_fs_type);
1170 unregister_fuseblk();
1171 kmem_cache_destroy(fuse_inode_cachep);
1172}
1173
1174static struct kobject *fuse_kobj;
1175static struct kobject *connections_kobj;
1176
1177static int fuse_sysfs_init(void)
1178{
1179 int err;
1180
1181 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1182 if (!fuse_kobj) {
1183 err = -ENOMEM;
1184 goto out_err;
1185 }
1186
1187 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1188 if (!connections_kobj) {
1189 err = -ENOMEM;
1190 goto out_fuse_unregister;
1191 }
1192
1193 return 0;
1194
1195 out_fuse_unregister:
1196 kobject_put(fuse_kobj);
1197 out_err:
1198 return err;
1199}
1200
1201static void fuse_sysfs_cleanup(void)
1202{
1203 kobject_put(connections_kobj);
1204 kobject_put(fuse_kobj);
1205}
1206
1207static int __init fuse_init(void)
1208{
1209 int res;
1210
1211 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1212 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1213
1214 INIT_LIST_HEAD(&fuse_conn_list);
1215 res = fuse_fs_init();
1216 if (res)
1217 goto err;
1218
1219 res = fuse_dev_init();
1220 if (res)
1221 goto err_fs_cleanup;
1222
1223 res = fuse_sysfs_init();
1224 if (res)
1225 goto err_dev_cleanup;
1226
1227 res = fuse_ctl_init();
1228 if (res)
1229 goto err_sysfs_cleanup;
1230
1231 sanitize_global_limit(&max_user_bgreq);
1232 sanitize_global_limit(&max_user_congthresh);
1233
1234 return 0;
1235
1236 err_sysfs_cleanup:
1237 fuse_sysfs_cleanup();
1238 err_dev_cleanup:
1239 fuse_dev_cleanup();
1240 err_fs_cleanup:
1241 fuse_fs_cleanup();
1242 err:
1243 return res;
1244}
1245
1246static void __exit fuse_exit(void)
1247{
1248 printk(KERN_DEBUG "fuse exit\n");
1249
1250 fuse_ctl_cleanup();
1251 fuse_sysfs_cleanup();
1252 fuse_fs_cleanup();
1253 fuse_dev_cleanup();
1254}
1255
1256module_init(fuse_init);
1257module_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#include <uapi/linux/magic.h>
27
28MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
29MODULE_DESCRIPTION("Filesystem in Userspace");
30MODULE_LICENSE("GPL");
31
32static struct kmem_cache *fuse_inode_cachep;
33struct list_head fuse_conn_list;
34DEFINE_MUTEX(fuse_mutex);
35
36static int set_global_limit(const char *val, const struct kernel_param *kp);
37
38unsigned max_user_bgreq;
39module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
40 &max_user_bgreq, 0644);
41__MODULE_PARM_TYPE(max_user_bgreq, "uint");
42MODULE_PARM_DESC(max_user_bgreq,
43 "Global limit for the maximum number of backgrounded requests an "
44 "unprivileged user can set");
45
46unsigned max_user_congthresh;
47module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
48 &max_user_congthresh, 0644);
49__MODULE_PARM_TYPE(max_user_congthresh, "uint");
50MODULE_PARM_DESC(max_user_congthresh,
51 "Global limit for the maximum congestion threshold an "
52 "unprivileged user can set");
53
54#define FUSE_DEFAULT_BLKSIZE 512
55
56/** Maximum number of outstanding background requests */
57#define FUSE_DEFAULT_MAX_BACKGROUND 12
58
59/** Congestion starts at 75% of maximum */
60#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
61
62#ifdef CONFIG_BLOCK
63static struct file_system_type fuseblk_fs_type;
64#endif
65
66struct fuse_forget_link *fuse_alloc_forget(void)
67{
68 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
69}
70
71static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void)
72{
73 struct fuse_submount_lookup *sl;
74
75 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT);
76 if (!sl)
77 return NULL;
78 sl->forget = fuse_alloc_forget();
79 if (!sl->forget)
80 goto out_free;
81
82 return sl;
83
84out_free:
85 kfree(sl);
86 return NULL;
87}
88
89static struct inode *fuse_alloc_inode(struct super_block *sb)
90{
91 struct fuse_inode *fi;
92
93 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
94 if (!fi)
95 return NULL;
96
97 fi->i_time = 0;
98 fi->inval_mask = ~0;
99 fi->nodeid = 0;
100 fi->nlookup = 0;
101 fi->attr_version = 0;
102 fi->orig_ino = 0;
103 fi->state = 0;
104 fi->submount_lookup = NULL;
105 mutex_init(&fi->mutex);
106 spin_lock_init(&fi->lock);
107 fi->forget = fuse_alloc_forget();
108 if (!fi->forget)
109 goto out_free;
110
111 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
112 goto out_free_forget;
113
114 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
115 fuse_inode_backing_set(fi, NULL);
116
117 return &fi->inode;
118
119out_free_forget:
120 kfree(fi->forget);
121out_free:
122 kmem_cache_free(fuse_inode_cachep, fi);
123 return NULL;
124}
125
126static void fuse_free_inode(struct inode *inode)
127{
128 struct fuse_inode *fi = get_fuse_inode(inode);
129
130 mutex_destroy(&fi->mutex);
131 kfree(fi->forget);
132#ifdef CONFIG_FUSE_DAX
133 kfree(fi->dax);
134#endif
135 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
136 fuse_backing_put(fuse_inode_backing(fi));
137
138 kmem_cache_free(fuse_inode_cachep, fi);
139}
140
141static void fuse_cleanup_submount_lookup(struct fuse_conn *fc,
142 struct fuse_submount_lookup *sl)
143{
144 if (!refcount_dec_and_test(&sl->count))
145 return;
146
147 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1);
148 sl->forget = NULL;
149 kfree(sl);
150}
151
152static void fuse_evict_inode(struct inode *inode)
153{
154 struct fuse_inode *fi = get_fuse_inode(inode);
155
156 /* Will write inode on close/munmap and in all other dirtiers */
157 WARN_ON(inode->i_state & I_DIRTY_INODE);
158
159 truncate_inode_pages_final(&inode->i_data);
160 clear_inode(inode);
161 if (inode->i_sb->s_flags & SB_ACTIVE) {
162 struct fuse_conn *fc = get_fuse_conn(inode);
163
164 if (FUSE_IS_DAX(inode))
165 fuse_dax_inode_cleanup(inode);
166 if (fi->nlookup) {
167 fuse_queue_forget(fc, fi->forget, fi->nodeid,
168 fi->nlookup);
169 fi->forget = NULL;
170 }
171
172 if (fi->submount_lookup) {
173 fuse_cleanup_submount_lookup(fc, fi->submount_lookup);
174 fi->submount_lookup = NULL;
175 }
176 }
177 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
178 WARN_ON(fi->iocachectr != 0);
179 WARN_ON(!list_empty(&fi->write_files));
180 WARN_ON(!list_empty(&fi->queued_writes));
181 }
182}
183
184static int fuse_reconfigure(struct fs_context *fsc)
185{
186 struct super_block *sb = fsc->root->d_sb;
187
188 sync_filesystem(sb);
189 if (fsc->sb_flags & SB_MANDLOCK)
190 return -EINVAL;
191
192 return 0;
193}
194
195/*
196 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
197 * so that it will fit.
198 */
199static ino_t fuse_squash_ino(u64 ino64)
200{
201 ino_t ino = (ino_t) ino64;
202 if (sizeof(ino_t) < sizeof(u64))
203 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
204 return ino;
205}
206
207void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
208 struct fuse_statx *sx,
209 u64 attr_valid, u32 cache_mask)
210{
211 struct fuse_conn *fc = get_fuse_conn(inode);
212 struct fuse_inode *fi = get_fuse_inode(inode);
213
214 lockdep_assert_held(&fi->lock);
215
216 fi->attr_version = atomic64_inc_return(&fc->attr_version);
217 fi->i_time = attr_valid;
218 /* Clear basic stats from invalid mask */
219 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0);
220
221 inode->i_ino = fuse_squash_ino(attr->ino);
222 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
223 set_nlink(inode, attr->nlink);
224 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
225 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
226 inode->i_blocks = attr->blocks;
227
228 /* Sanitize nsecs */
229 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
230 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
231 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
232
233 inode_set_atime(inode, attr->atime, attr->atimensec);
234 /* mtime from server may be stale due to local buffered write */
235 if (!(cache_mask & STATX_MTIME)) {
236 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
237 }
238 if (!(cache_mask & STATX_CTIME)) {
239 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
240 }
241 if (sx) {
242 /* Sanitize nsecs */
243 sx->btime.tv_nsec =
244 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
245
246 /*
247 * Btime has been queried, cache is valid (whether or not btime
248 * is available or not) so clear STATX_BTIME from inval_mask.
249 *
250 * Availability of the btime attribute is indicated in
251 * FUSE_I_BTIME
252 */
253 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0);
254 if (sx->mask & STATX_BTIME) {
255 set_bit(FUSE_I_BTIME, &fi->state);
256 fi->i_btime.tv_sec = sx->btime.tv_sec;
257 fi->i_btime.tv_nsec = sx->btime.tv_nsec;
258 }
259 }
260
261 if (attr->blksize != 0)
262 inode->i_blkbits = ilog2(attr->blksize);
263 else
264 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
265
266 /*
267 * Don't set the sticky bit in i_mode, unless we want the VFS
268 * to check permissions. This prevents failures due to the
269 * check in may_delete().
270 */
271 fi->orig_i_mode = inode->i_mode;
272 if (!fc->default_permissions)
273 inode->i_mode &= ~S_ISVTX;
274
275 fi->orig_ino = attr->ino;
276
277 /*
278 * We are refreshing inode data and it is possible that another
279 * client set suid/sgid or security.capability xattr. So clear
280 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
281 * was set or if security.capability xattr was set. But we don't
282 * know if security.capability has been set or not. So clear it
283 * anyway. Its less efficient but should be safe.
284 */
285 inode->i_flags &= ~S_NOSEC;
286}
287
288u32 fuse_get_cache_mask(struct inode *inode)
289{
290 struct fuse_conn *fc = get_fuse_conn(inode);
291
292 if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
293 return 0;
294
295 return STATX_MTIME | STATX_CTIME | STATX_SIZE;
296}
297
298void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
299 struct fuse_statx *sx,
300 u64 attr_valid, u64 attr_version)
301{
302 struct fuse_conn *fc = get_fuse_conn(inode);
303 struct fuse_inode *fi = get_fuse_inode(inode);
304 u32 cache_mask;
305 loff_t oldsize;
306 struct timespec64 old_mtime;
307
308 spin_lock(&fi->lock);
309 /*
310 * In case of writeback_cache enabled, writes update mtime, ctime and
311 * may update i_size. In these cases trust the cached value in the
312 * inode.
313 */
314 cache_mask = fuse_get_cache_mask(inode);
315 if (cache_mask & STATX_SIZE)
316 attr->size = i_size_read(inode);
317
318 if (cache_mask & STATX_MTIME) {
319 attr->mtime = inode_get_mtime_sec(inode);
320 attr->mtimensec = inode_get_mtime_nsec(inode);
321 }
322 if (cache_mask & STATX_CTIME) {
323 attr->ctime = inode_get_ctime_sec(inode);
324 attr->ctimensec = inode_get_ctime_nsec(inode);
325 }
326
327 if ((attr_version != 0 && fi->attr_version > attr_version) ||
328 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
329 spin_unlock(&fi->lock);
330 return;
331 }
332
333 old_mtime = inode_get_mtime(inode);
334 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask);
335
336 oldsize = inode->i_size;
337 /*
338 * In case of writeback_cache enabled, the cached writes beyond EOF
339 * extend local i_size without keeping userspace server in sync. So,
340 * attr->size coming from server can be stale. We cannot trust it.
341 */
342 if (!(cache_mask & STATX_SIZE))
343 i_size_write(inode, attr->size);
344 spin_unlock(&fi->lock);
345
346 if (!cache_mask && S_ISREG(inode->i_mode)) {
347 bool inval = false;
348
349 if (oldsize != attr->size) {
350 truncate_pagecache(inode, attr->size);
351 if (!fc->explicit_inval_data)
352 inval = true;
353 } else if (fc->auto_inval_data) {
354 struct timespec64 new_mtime = {
355 .tv_sec = attr->mtime,
356 .tv_nsec = attr->mtimensec,
357 };
358
359 /*
360 * Auto inval mode also checks and invalidates if mtime
361 * has changed.
362 */
363 if (!timespec64_equal(&old_mtime, &new_mtime))
364 inval = true;
365 }
366
367 if (inval)
368 invalidate_inode_pages2(inode->i_mapping);
369 }
370
371 if (IS_ENABLED(CONFIG_FUSE_DAX))
372 fuse_dax_dontcache(inode, attr->flags);
373}
374
375static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl,
376 u64 nodeid)
377{
378 sl->nodeid = nodeid;
379 refcount_set(&sl->count, 1);
380}
381
382static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr,
383 struct fuse_conn *fc)
384{
385 inode->i_mode = attr->mode & S_IFMT;
386 inode->i_size = attr->size;
387 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
388 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
389 if (S_ISREG(inode->i_mode)) {
390 fuse_init_common(inode);
391 fuse_init_file_inode(inode, attr->flags);
392 } else if (S_ISDIR(inode->i_mode))
393 fuse_init_dir(inode);
394 else if (S_ISLNK(inode->i_mode))
395 fuse_init_symlink(inode);
396 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
397 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
398 fuse_init_common(inode);
399 init_special_inode(inode, inode->i_mode,
400 new_decode_dev(attr->rdev));
401 } else
402 BUG();
403 /*
404 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL
405 * so they see the exact same behavior as before.
406 */
407 if (!fc->posix_acl)
408 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
409}
410
411static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
412{
413 u64 nodeid = *(u64 *) _nodeidp;
414 if (get_node_id(inode) == nodeid)
415 return 1;
416 else
417 return 0;
418}
419
420static int fuse_inode_set(struct inode *inode, void *_nodeidp)
421{
422 u64 nodeid = *(u64 *) _nodeidp;
423 get_fuse_inode(inode)->nodeid = nodeid;
424 return 0;
425}
426
427struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
428 int generation, struct fuse_attr *attr,
429 u64 attr_valid, u64 attr_version)
430{
431 struct inode *inode;
432 struct fuse_inode *fi;
433 struct fuse_conn *fc = get_fuse_conn_super(sb);
434
435 /*
436 * Auto mount points get their node id from the submount root, which is
437 * not a unique identifier within this filesystem.
438 *
439 * To avoid conflicts, do not place submount points into the inode hash
440 * table.
441 */
442 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
443 S_ISDIR(attr->mode)) {
444 struct fuse_inode *fi;
445
446 inode = new_inode(sb);
447 if (!inode)
448 return NULL;
449
450 fuse_init_inode(inode, attr, fc);
451 fi = get_fuse_inode(inode);
452 fi->nodeid = nodeid;
453 fi->submount_lookup = fuse_alloc_submount_lookup();
454 if (!fi->submount_lookup) {
455 iput(inode);
456 return NULL;
457 }
458 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */
459 fuse_init_submount_lookup(fi->submount_lookup, nodeid);
460 inode->i_flags |= S_AUTOMOUNT;
461 goto done;
462 }
463
464retry:
465 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
466 if (!inode)
467 return NULL;
468
469 if ((inode->i_state & I_NEW)) {
470 inode->i_flags |= S_NOATIME;
471 if (!fc->writeback_cache || !S_ISREG(attr->mode))
472 inode->i_flags |= S_NOCMTIME;
473 inode->i_generation = generation;
474 fuse_init_inode(inode, attr, fc);
475 unlock_new_inode(inode);
476 } else if (fuse_stale_inode(inode, generation, attr)) {
477 /* nodeid was reused, any I/O on the old inode should fail */
478 fuse_make_bad(inode);
479 if (inode != d_inode(sb->s_root)) {
480 remove_inode_hash(inode);
481 iput(inode);
482 goto retry;
483 }
484 }
485 fi = get_fuse_inode(inode);
486 spin_lock(&fi->lock);
487 fi->nlookup++;
488 spin_unlock(&fi->lock);
489done:
490 fuse_change_attributes(inode, attr, NULL, attr_valid, attr_version);
491
492 return inode;
493}
494
495struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
496 struct fuse_mount **fm)
497{
498 struct fuse_mount *fm_iter;
499 struct inode *inode;
500
501 WARN_ON(!rwsem_is_locked(&fc->killsb));
502 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
503 if (!fm_iter->sb)
504 continue;
505
506 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
507 if (inode) {
508 if (fm)
509 *fm = fm_iter;
510 return inode;
511 }
512 }
513
514 return NULL;
515}
516
517int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
518 loff_t offset, loff_t len)
519{
520 struct fuse_inode *fi;
521 struct inode *inode;
522 pgoff_t pg_start;
523 pgoff_t pg_end;
524
525 inode = fuse_ilookup(fc, nodeid, NULL);
526 if (!inode)
527 return -ENOENT;
528
529 fi = get_fuse_inode(inode);
530 spin_lock(&fi->lock);
531 fi->attr_version = atomic64_inc_return(&fc->attr_version);
532 spin_unlock(&fi->lock);
533
534 fuse_invalidate_attr(inode);
535 forget_all_cached_acls(inode);
536 if (offset >= 0) {
537 pg_start = offset >> PAGE_SHIFT;
538 if (len <= 0)
539 pg_end = -1;
540 else
541 pg_end = (offset + len - 1) >> PAGE_SHIFT;
542 invalidate_inode_pages2_range(inode->i_mapping,
543 pg_start, pg_end);
544 }
545 iput(inode);
546 return 0;
547}
548
549bool fuse_lock_inode(struct inode *inode)
550{
551 bool locked = false;
552
553 if (!get_fuse_conn(inode)->parallel_dirops) {
554 mutex_lock(&get_fuse_inode(inode)->mutex);
555 locked = true;
556 }
557
558 return locked;
559}
560
561void fuse_unlock_inode(struct inode *inode, bool locked)
562{
563 if (locked)
564 mutex_unlock(&get_fuse_inode(inode)->mutex);
565}
566
567static void fuse_umount_begin(struct super_block *sb)
568{
569 struct fuse_conn *fc = get_fuse_conn_super(sb);
570
571 if (fc->no_force_umount)
572 return;
573
574 fuse_abort_conn(fc);
575
576 // Only retire block-device-based superblocks.
577 if (sb->s_bdev != NULL)
578 retire_super(sb);
579}
580
581static void fuse_send_destroy(struct fuse_mount *fm)
582{
583 if (fm->fc->conn_init) {
584 FUSE_ARGS(args);
585
586 args.opcode = FUSE_DESTROY;
587 args.force = true;
588 args.nocreds = true;
589 fuse_simple_request(fm, &args);
590 }
591}
592
593static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
594{
595 stbuf->f_type = FUSE_SUPER_MAGIC;
596 stbuf->f_bsize = attr->bsize;
597 stbuf->f_frsize = attr->frsize;
598 stbuf->f_blocks = attr->blocks;
599 stbuf->f_bfree = attr->bfree;
600 stbuf->f_bavail = attr->bavail;
601 stbuf->f_files = attr->files;
602 stbuf->f_ffree = attr->ffree;
603 stbuf->f_namelen = attr->namelen;
604 /* fsid is left zero */
605}
606
607static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
608{
609 struct super_block *sb = dentry->d_sb;
610 struct fuse_mount *fm = get_fuse_mount_super(sb);
611 FUSE_ARGS(args);
612 struct fuse_statfs_out outarg;
613 int err;
614
615 if (!fuse_allow_current_process(fm->fc)) {
616 buf->f_type = FUSE_SUPER_MAGIC;
617 return 0;
618 }
619
620 memset(&outarg, 0, sizeof(outarg));
621 args.in_numargs = 0;
622 args.opcode = FUSE_STATFS;
623 args.nodeid = get_node_id(d_inode(dentry));
624 args.out_numargs = 1;
625 args.out_args[0].size = sizeof(outarg);
626 args.out_args[0].value = &outarg;
627 err = fuse_simple_request(fm, &args);
628 if (!err)
629 convert_fuse_statfs(buf, &outarg.st);
630 return err;
631}
632
633static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
634{
635 struct fuse_sync_bucket *bucket;
636
637 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
638 if (bucket) {
639 init_waitqueue_head(&bucket->waitq);
640 /* Initial active count */
641 atomic_set(&bucket->count, 1);
642 }
643 return bucket;
644}
645
646static void fuse_sync_fs_writes(struct fuse_conn *fc)
647{
648 struct fuse_sync_bucket *bucket, *new_bucket;
649 int count;
650
651 new_bucket = fuse_sync_bucket_alloc();
652 spin_lock(&fc->lock);
653 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
654 count = atomic_read(&bucket->count);
655 WARN_ON(count < 1);
656 /* No outstanding writes? */
657 if (count == 1) {
658 spin_unlock(&fc->lock);
659 kfree(new_bucket);
660 return;
661 }
662
663 /*
664 * Completion of new bucket depends on completion of this bucket, so add
665 * one more count.
666 */
667 atomic_inc(&new_bucket->count);
668 rcu_assign_pointer(fc->curr_bucket, new_bucket);
669 spin_unlock(&fc->lock);
670 /*
671 * Drop initial active count. At this point if all writes in this and
672 * ancestor buckets complete, the count will go to zero and this task
673 * will be woken up.
674 */
675 atomic_dec(&bucket->count);
676
677 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
678
679 /* Drop temp count on descendant bucket */
680 fuse_sync_bucket_dec(new_bucket);
681 kfree_rcu(bucket, rcu);
682}
683
684static int fuse_sync_fs(struct super_block *sb, int wait)
685{
686 struct fuse_mount *fm = get_fuse_mount_super(sb);
687 struct fuse_conn *fc = fm->fc;
688 struct fuse_syncfs_in inarg;
689 FUSE_ARGS(args);
690 int err;
691
692 /*
693 * Userspace cannot handle the wait == 0 case. Avoid a
694 * gratuitous roundtrip.
695 */
696 if (!wait)
697 return 0;
698
699 /* The filesystem is being unmounted. Nothing to do. */
700 if (!sb->s_root)
701 return 0;
702
703 if (!fc->sync_fs)
704 return 0;
705
706 fuse_sync_fs_writes(fc);
707
708 memset(&inarg, 0, sizeof(inarg));
709 args.in_numargs = 1;
710 args.in_args[0].size = sizeof(inarg);
711 args.in_args[0].value = &inarg;
712 args.opcode = FUSE_SYNCFS;
713 args.nodeid = get_node_id(sb->s_root->d_inode);
714 args.out_numargs = 0;
715
716 err = fuse_simple_request(fm, &args);
717 if (err == -ENOSYS) {
718 fc->sync_fs = 0;
719 err = 0;
720 }
721
722 return err;
723}
724
725enum {
726 OPT_SOURCE,
727 OPT_SUBTYPE,
728 OPT_FD,
729 OPT_ROOTMODE,
730 OPT_USER_ID,
731 OPT_GROUP_ID,
732 OPT_DEFAULT_PERMISSIONS,
733 OPT_ALLOW_OTHER,
734 OPT_MAX_READ,
735 OPT_BLKSIZE,
736 OPT_ERR
737};
738
739static const struct fs_parameter_spec fuse_fs_parameters[] = {
740 fsparam_string ("source", OPT_SOURCE),
741 fsparam_u32 ("fd", OPT_FD),
742 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
743 fsparam_u32 ("user_id", OPT_USER_ID),
744 fsparam_u32 ("group_id", OPT_GROUP_ID),
745 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
746 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
747 fsparam_u32 ("max_read", OPT_MAX_READ),
748 fsparam_u32 ("blksize", OPT_BLKSIZE),
749 fsparam_string ("subtype", OPT_SUBTYPE),
750 {}
751};
752
753static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
754{
755 struct fs_parse_result result;
756 struct fuse_fs_context *ctx = fsc->fs_private;
757 int opt;
758
759 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
760 /*
761 * Ignore options coming from mount(MS_REMOUNT) for backward
762 * compatibility.
763 */
764 if (fsc->oldapi)
765 return 0;
766
767 return invalfc(fsc, "No changes allowed in reconfigure");
768 }
769
770 opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
771 if (opt < 0)
772 return opt;
773
774 switch (opt) {
775 case OPT_SOURCE:
776 if (fsc->source)
777 return invalfc(fsc, "Multiple sources specified");
778 fsc->source = param->string;
779 param->string = NULL;
780 break;
781
782 case OPT_SUBTYPE:
783 if (ctx->subtype)
784 return invalfc(fsc, "Multiple subtypes specified");
785 ctx->subtype = param->string;
786 param->string = NULL;
787 return 0;
788
789 case OPT_FD:
790 ctx->fd = result.uint_32;
791 ctx->fd_present = true;
792 break;
793
794 case OPT_ROOTMODE:
795 if (!fuse_valid_type(result.uint_32))
796 return invalfc(fsc, "Invalid rootmode");
797 ctx->rootmode = result.uint_32;
798 ctx->rootmode_present = true;
799 break;
800
801 case OPT_USER_ID:
802 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
803 if (!uid_valid(ctx->user_id))
804 return invalfc(fsc, "Invalid user_id");
805 ctx->user_id_present = true;
806 break;
807
808 case OPT_GROUP_ID:
809 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
810 if (!gid_valid(ctx->group_id))
811 return invalfc(fsc, "Invalid group_id");
812 ctx->group_id_present = true;
813 break;
814
815 case OPT_DEFAULT_PERMISSIONS:
816 ctx->default_permissions = true;
817 break;
818
819 case OPT_ALLOW_OTHER:
820 ctx->allow_other = true;
821 break;
822
823 case OPT_MAX_READ:
824 ctx->max_read = result.uint_32;
825 break;
826
827 case OPT_BLKSIZE:
828 if (!ctx->is_bdev)
829 return invalfc(fsc, "blksize only supported for fuseblk");
830 ctx->blksize = result.uint_32;
831 break;
832
833 default:
834 return -EINVAL;
835 }
836
837 return 0;
838}
839
840static void fuse_free_fsc(struct fs_context *fsc)
841{
842 struct fuse_fs_context *ctx = fsc->fs_private;
843
844 if (ctx) {
845 kfree(ctx->subtype);
846 kfree(ctx);
847 }
848}
849
850static int fuse_show_options(struct seq_file *m, struct dentry *root)
851{
852 struct super_block *sb = root->d_sb;
853 struct fuse_conn *fc = get_fuse_conn_super(sb);
854
855 if (fc->legacy_opts_show) {
856 seq_printf(m, ",user_id=%u",
857 from_kuid_munged(fc->user_ns, fc->user_id));
858 seq_printf(m, ",group_id=%u",
859 from_kgid_munged(fc->user_ns, fc->group_id));
860 if (fc->default_permissions)
861 seq_puts(m, ",default_permissions");
862 if (fc->allow_other)
863 seq_puts(m, ",allow_other");
864 if (fc->max_read != ~0)
865 seq_printf(m, ",max_read=%u", fc->max_read);
866 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
867 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
868 }
869#ifdef CONFIG_FUSE_DAX
870 if (fc->dax_mode == FUSE_DAX_ALWAYS)
871 seq_puts(m, ",dax=always");
872 else if (fc->dax_mode == FUSE_DAX_NEVER)
873 seq_puts(m, ",dax=never");
874 else if (fc->dax_mode == FUSE_DAX_INODE_USER)
875 seq_puts(m, ",dax=inode");
876#endif
877
878 return 0;
879}
880
881static void fuse_iqueue_init(struct fuse_iqueue *fiq,
882 const struct fuse_iqueue_ops *ops,
883 void *priv)
884{
885 memset(fiq, 0, sizeof(struct fuse_iqueue));
886 spin_lock_init(&fiq->lock);
887 init_waitqueue_head(&fiq->waitq);
888 INIT_LIST_HEAD(&fiq->pending);
889 INIT_LIST_HEAD(&fiq->interrupts);
890 fiq->forget_list_tail = &fiq->forget_list_head;
891 fiq->connected = 1;
892 fiq->ops = ops;
893 fiq->priv = priv;
894}
895
896static void fuse_pqueue_init(struct fuse_pqueue *fpq)
897{
898 unsigned int i;
899
900 spin_lock_init(&fpq->lock);
901 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
902 INIT_LIST_HEAD(&fpq->processing[i]);
903 INIT_LIST_HEAD(&fpq->io);
904 fpq->connected = 1;
905}
906
907void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
908 struct user_namespace *user_ns,
909 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
910{
911 memset(fc, 0, sizeof(*fc));
912 spin_lock_init(&fc->lock);
913 spin_lock_init(&fc->bg_lock);
914 init_rwsem(&fc->killsb);
915 refcount_set(&fc->count, 1);
916 atomic_set(&fc->dev_count, 1);
917 init_waitqueue_head(&fc->blocked_waitq);
918 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
919 INIT_LIST_HEAD(&fc->bg_queue);
920 INIT_LIST_HEAD(&fc->entry);
921 INIT_LIST_HEAD(&fc->devices);
922 atomic_set(&fc->num_waiting, 0);
923 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
924 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
925 atomic64_set(&fc->khctr, 0);
926 fc->polled_files = RB_ROOT;
927 fc->blocked = 0;
928 fc->initialized = 0;
929 fc->connected = 1;
930 atomic64_set(&fc->attr_version, 1);
931 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
932 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
933 fc->user_ns = get_user_ns(user_ns);
934 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
935 fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
936
937 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
938 fuse_backing_files_init(fc);
939
940 INIT_LIST_HEAD(&fc->mounts);
941 list_add(&fm->fc_entry, &fc->mounts);
942 fm->fc = fc;
943}
944EXPORT_SYMBOL_GPL(fuse_conn_init);
945
946static void delayed_release(struct rcu_head *p)
947{
948 struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu);
949
950 put_user_ns(fc->user_ns);
951 fc->release(fc);
952}
953
954void fuse_conn_put(struct fuse_conn *fc)
955{
956 if (refcount_dec_and_test(&fc->count)) {
957 struct fuse_iqueue *fiq = &fc->iq;
958 struct fuse_sync_bucket *bucket;
959
960 if (IS_ENABLED(CONFIG_FUSE_DAX))
961 fuse_dax_conn_free(fc);
962 if (fiq->ops->release)
963 fiq->ops->release(fiq);
964 put_pid_ns(fc->pid_ns);
965 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
966 if (bucket) {
967 WARN_ON(atomic_read(&bucket->count) != 1);
968 kfree(bucket);
969 }
970 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
971 fuse_backing_files_free(fc);
972 call_rcu(&fc->rcu, delayed_release);
973 }
974}
975EXPORT_SYMBOL_GPL(fuse_conn_put);
976
977struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
978{
979 refcount_inc(&fc->count);
980 return fc;
981}
982EXPORT_SYMBOL_GPL(fuse_conn_get);
983
984static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
985{
986 struct fuse_attr attr;
987 memset(&attr, 0, sizeof(attr));
988
989 attr.mode = mode;
990 attr.ino = FUSE_ROOT_ID;
991 attr.nlink = 1;
992 return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0);
993}
994
995struct fuse_inode_handle {
996 u64 nodeid;
997 u32 generation;
998};
999
1000static struct dentry *fuse_get_dentry(struct super_block *sb,
1001 struct fuse_inode_handle *handle)
1002{
1003 struct fuse_conn *fc = get_fuse_conn_super(sb);
1004 struct inode *inode;
1005 struct dentry *entry;
1006 int err = -ESTALE;
1007
1008 if (handle->nodeid == 0)
1009 goto out_err;
1010
1011 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
1012 if (!inode) {
1013 struct fuse_entry_out outarg;
1014 const struct qstr name = QSTR_INIT(".", 1);
1015
1016 if (!fc->export_support)
1017 goto out_err;
1018
1019 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
1020 &inode);
1021 if (err && err != -ENOENT)
1022 goto out_err;
1023 if (err || !inode) {
1024 err = -ESTALE;
1025 goto out_err;
1026 }
1027 err = -EIO;
1028 if (get_node_id(inode) != handle->nodeid)
1029 goto out_iput;
1030 }
1031 err = -ESTALE;
1032 if (inode->i_generation != handle->generation)
1033 goto out_iput;
1034
1035 entry = d_obtain_alias(inode);
1036 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
1037 fuse_invalidate_entry_cache(entry);
1038
1039 return entry;
1040
1041 out_iput:
1042 iput(inode);
1043 out_err:
1044 return ERR_PTR(err);
1045}
1046
1047static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
1048 struct inode *parent)
1049{
1050 int len = parent ? 6 : 3;
1051 u64 nodeid;
1052 u32 generation;
1053
1054 if (*max_len < len) {
1055 *max_len = len;
1056 return FILEID_INVALID;
1057 }
1058
1059 nodeid = get_fuse_inode(inode)->nodeid;
1060 generation = inode->i_generation;
1061
1062 fh[0] = (u32)(nodeid >> 32);
1063 fh[1] = (u32)(nodeid & 0xffffffff);
1064 fh[2] = generation;
1065
1066 if (parent) {
1067 nodeid = get_fuse_inode(parent)->nodeid;
1068 generation = parent->i_generation;
1069
1070 fh[3] = (u32)(nodeid >> 32);
1071 fh[4] = (u32)(nodeid & 0xffffffff);
1072 fh[5] = generation;
1073 }
1074
1075 *max_len = len;
1076 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
1077}
1078
1079static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
1080 struct fid *fid, int fh_len, int fh_type)
1081{
1082 struct fuse_inode_handle handle;
1083
1084 if ((fh_type != FILEID_INO64_GEN &&
1085 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
1086 return NULL;
1087
1088 handle.nodeid = (u64) fid->raw[0] << 32;
1089 handle.nodeid |= (u64) fid->raw[1];
1090 handle.generation = fid->raw[2];
1091 return fuse_get_dentry(sb, &handle);
1092}
1093
1094static struct dentry *fuse_fh_to_parent(struct super_block *sb,
1095 struct fid *fid, int fh_len, int fh_type)
1096{
1097 struct fuse_inode_handle parent;
1098
1099 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
1100 return NULL;
1101
1102 parent.nodeid = (u64) fid->raw[3] << 32;
1103 parent.nodeid |= (u64) fid->raw[4];
1104 parent.generation = fid->raw[5];
1105 return fuse_get_dentry(sb, &parent);
1106}
1107
1108static struct dentry *fuse_get_parent(struct dentry *child)
1109{
1110 struct inode *child_inode = d_inode(child);
1111 struct fuse_conn *fc = get_fuse_conn(child_inode);
1112 struct inode *inode;
1113 struct dentry *parent;
1114 struct fuse_entry_out outarg;
1115 int err;
1116
1117 if (!fc->export_support)
1118 return ERR_PTR(-ESTALE);
1119
1120 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1121 &dotdot_name, &outarg, &inode);
1122 if (err) {
1123 if (err == -ENOENT)
1124 return ERR_PTR(-ESTALE);
1125 return ERR_PTR(err);
1126 }
1127
1128 parent = d_obtain_alias(inode);
1129 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1130 fuse_invalidate_entry_cache(parent);
1131
1132 return parent;
1133}
1134
1135/* only for fid encoding; no support for file handle */
1136static const struct export_operations fuse_export_fid_operations = {
1137 .encode_fh = fuse_encode_fh,
1138};
1139
1140static const struct export_operations fuse_export_operations = {
1141 .fh_to_dentry = fuse_fh_to_dentry,
1142 .fh_to_parent = fuse_fh_to_parent,
1143 .encode_fh = fuse_encode_fh,
1144 .get_parent = fuse_get_parent,
1145};
1146
1147static const struct super_operations fuse_super_operations = {
1148 .alloc_inode = fuse_alloc_inode,
1149 .free_inode = fuse_free_inode,
1150 .evict_inode = fuse_evict_inode,
1151 .write_inode = fuse_write_inode,
1152 .drop_inode = generic_delete_inode,
1153 .umount_begin = fuse_umount_begin,
1154 .statfs = fuse_statfs,
1155 .sync_fs = fuse_sync_fs,
1156 .show_options = fuse_show_options,
1157};
1158
1159static void sanitize_global_limit(unsigned *limit)
1160{
1161 /*
1162 * The default maximum number of async requests is calculated to consume
1163 * 1/2^13 of the total memory, assuming 392 bytes per request.
1164 */
1165 if (*limit == 0)
1166 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1167
1168 if (*limit >= 1 << 16)
1169 *limit = (1 << 16) - 1;
1170}
1171
1172static int set_global_limit(const char *val, const struct kernel_param *kp)
1173{
1174 int rv;
1175
1176 rv = param_set_uint(val, kp);
1177 if (rv)
1178 return rv;
1179
1180 sanitize_global_limit((unsigned *)kp->arg);
1181
1182 return 0;
1183}
1184
1185static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1186{
1187 int cap_sys_admin = capable(CAP_SYS_ADMIN);
1188
1189 if (arg->minor < 13)
1190 return;
1191
1192 sanitize_global_limit(&max_user_bgreq);
1193 sanitize_global_limit(&max_user_congthresh);
1194
1195 spin_lock(&fc->bg_lock);
1196 if (arg->max_background) {
1197 fc->max_background = arg->max_background;
1198
1199 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1200 fc->max_background = max_user_bgreq;
1201 }
1202 if (arg->congestion_threshold) {
1203 fc->congestion_threshold = arg->congestion_threshold;
1204
1205 if (!cap_sys_admin &&
1206 fc->congestion_threshold > max_user_congthresh)
1207 fc->congestion_threshold = max_user_congthresh;
1208 }
1209 spin_unlock(&fc->bg_lock);
1210}
1211
1212struct fuse_init_args {
1213 struct fuse_args args;
1214 struct fuse_init_in in;
1215 struct fuse_init_out out;
1216};
1217
1218static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1219 int error)
1220{
1221 struct fuse_conn *fc = fm->fc;
1222 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1223 struct fuse_init_out *arg = &ia->out;
1224 bool ok = true;
1225
1226 if (error || arg->major != FUSE_KERNEL_VERSION)
1227 ok = false;
1228 else {
1229 unsigned long ra_pages;
1230
1231 process_init_limits(fc, arg);
1232
1233 if (arg->minor >= 6) {
1234 u64 flags = arg->flags;
1235
1236 if (flags & FUSE_INIT_EXT)
1237 flags |= (u64) arg->flags2 << 32;
1238
1239 ra_pages = arg->max_readahead / PAGE_SIZE;
1240 if (flags & FUSE_ASYNC_READ)
1241 fc->async_read = 1;
1242 if (!(flags & FUSE_POSIX_LOCKS))
1243 fc->no_lock = 1;
1244 if (arg->minor >= 17) {
1245 if (!(flags & FUSE_FLOCK_LOCKS))
1246 fc->no_flock = 1;
1247 } else {
1248 if (!(flags & FUSE_POSIX_LOCKS))
1249 fc->no_flock = 1;
1250 }
1251 if (flags & FUSE_ATOMIC_O_TRUNC)
1252 fc->atomic_o_trunc = 1;
1253 if (arg->minor >= 9) {
1254 /* LOOKUP has dependency on proto version */
1255 if (flags & FUSE_EXPORT_SUPPORT)
1256 fc->export_support = 1;
1257 }
1258 if (flags & FUSE_BIG_WRITES)
1259 fc->big_writes = 1;
1260 if (flags & FUSE_DONT_MASK)
1261 fc->dont_mask = 1;
1262 if (flags & FUSE_AUTO_INVAL_DATA)
1263 fc->auto_inval_data = 1;
1264 else if (flags & FUSE_EXPLICIT_INVAL_DATA)
1265 fc->explicit_inval_data = 1;
1266 if (flags & FUSE_DO_READDIRPLUS) {
1267 fc->do_readdirplus = 1;
1268 if (flags & FUSE_READDIRPLUS_AUTO)
1269 fc->readdirplus_auto = 1;
1270 }
1271 if (flags & FUSE_ASYNC_DIO)
1272 fc->async_dio = 1;
1273 if (flags & FUSE_WRITEBACK_CACHE)
1274 fc->writeback_cache = 1;
1275 if (flags & FUSE_PARALLEL_DIROPS)
1276 fc->parallel_dirops = 1;
1277 if (flags & FUSE_HANDLE_KILLPRIV)
1278 fc->handle_killpriv = 1;
1279 if (arg->time_gran && arg->time_gran <= 1000000000)
1280 fm->sb->s_time_gran = arg->time_gran;
1281 if ((flags & FUSE_POSIX_ACL)) {
1282 fc->default_permissions = 1;
1283 fc->posix_acl = 1;
1284 }
1285 if (flags & FUSE_CACHE_SYMLINKS)
1286 fc->cache_symlinks = 1;
1287 if (flags & FUSE_ABORT_ERROR)
1288 fc->abort_err = 1;
1289 if (flags & FUSE_MAX_PAGES) {
1290 fc->max_pages =
1291 min_t(unsigned int, fc->max_pages_limit,
1292 max_t(unsigned int, arg->max_pages, 1));
1293 }
1294 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1295 if (flags & FUSE_MAP_ALIGNMENT &&
1296 !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1297 ok = false;
1298 }
1299 if (flags & FUSE_HAS_INODE_DAX)
1300 fc->inode_dax = 1;
1301 }
1302 if (flags & FUSE_HANDLE_KILLPRIV_V2) {
1303 fc->handle_killpriv_v2 = 1;
1304 fm->sb->s_flags |= SB_NOSEC;
1305 }
1306 if (flags & FUSE_SETXATTR_EXT)
1307 fc->setxattr_ext = 1;
1308 if (flags & FUSE_SECURITY_CTX)
1309 fc->init_security = 1;
1310 if (flags & FUSE_CREATE_SUPP_GROUP)
1311 fc->create_supp_group = 1;
1312 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP)
1313 fc->direct_io_allow_mmap = 1;
1314 /*
1315 * max_stack_depth is the max stack depth of FUSE fs,
1316 * so it has to be at least 1 to support passthrough
1317 * to backing files.
1318 *
1319 * with max_stack_depth > 1, the backing files can be
1320 * on a stacked fs (e.g. overlayfs) themselves and with
1321 * max_stack_depth == 1, FUSE fs can be stacked as the
1322 * underlying fs of a stacked fs (e.g. overlayfs).
1323 */
1324 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) &&
1325 (flags & FUSE_PASSTHROUGH) &&
1326 arg->max_stack_depth > 0 &&
1327 arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH) {
1328 fc->passthrough = 1;
1329 fc->max_stack_depth = arg->max_stack_depth;
1330 fm->sb->s_stack_depth = arg->max_stack_depth;
1331 }
1332 if (flags & FUSE_NO_EXPORT_SUPPORT)
1333 fm->sb->s_export_op = &fuse_export_fid_operations;
1334 } else {
1335 ra_pages = fc->max_read / PAGE_SIZE;
1336 fc->no_lock = 1;
1337 fc->no_flock = 1;
1338 }
1339
1340 fm->sb->s_bdi->ra_pages =
1341 min(fm->sb->s_bdi->ra_pages, ra_pages);
1342 fc->minor = arg->minor;
1343 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1344 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1345 fc->conn_init = 1;
1346 }
1347 kfree(ia);
1348
1349 if (!ok) {
1350 fc->conn_init = 0;
1351 fc->conn_error = 1;
1352 }
1353
1354 fuse_set_initialized(fc);
1355 wake_up_all(&fc->blocked_waitq);
1356}
1357
1358void fuse_send_init(struct fuse_mount *fm)
1359{
1360 struct fuse_init_args *ia;
1361 u64 flags;
1362
1363 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1364
1365 ia->in.major = FUSE_KERNEL_VERSION;
1366 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1367 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1368 flags =
1369 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1370 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1371 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1372 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1373 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1374 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1375 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1376 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1377 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1378 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
1379 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP |
1380 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP |
1381 FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND;
1382#ifdef CONFIG_FUSE_DAX
1383 if (fm->fc->dax)
1384 flags |= FUSE_MAP_ALIGNMENT;
1385 if (fuse_is_inode_dax_mode(fm->fc->dax_mode))
1386 flags |= FUSE_HAS_INODE_DAX;
1387#endif
1388 if (fm->fc->auto_submounts)
1389 flags |= FUSE_SUBMOUNTS;
1390 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
1391 flags |= FUSE_PASSTHROUGH;
1392
1393 ia->in.flags = flags;
1394 ia->in.flags2 = flags >> 32;
1395
1396 ia->args.opcode = FUSE_INIT;
1397 ia->args.in_numargs = 1;
1398 ia->args.in_args[0].size = sizeof(ia->in);
1399 ia->args.in_args[0].value = &ia->in;
1400 ia->args.out_numargs = 1;
1401 /* Variable length argument used for backward compatibility
1402 with interface version < 7.5. Rest of init_out is zeroed
1403 by do_get_request(), so a short reply is not a problem */
1404 ia->args.out_argvar = true;
1405 ia->args.out_args[0].size = sizeof(ia->out);
1406 ia->args.out_args[0].value = &ia->out;
1407 ia->args.force = true;
1408 ia->args.nocreds = true;
1409 ia->args.end = process_init_reply;
1410
1411 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1412 process_init_reply(fm, &ia->args, -ENOTCONN);
1413}
1414EXPORT_SYMBOL_GPL(fuse_send_init);
1415
1416void fuse_free_conn(struct fuse_conn *fc)
1417{
1418 WARN_ON(!list_empty(&fc->devices));
1419 kfree(fc);
1420}
1421EXPORT_SYMBOL_GPL(fuse_free_conn);
1422
1423static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1424{
1425 int err;
1426 char *suffix = "";
1427
1428 if (sb->s_bdev) {
1429 suffix = "-fuseblk";
1430 /*
1431 * sb->s_bdi points to blkdev's bdi however we want to redirect
1432 * it to our private bdi...
1433 */
1434 bdi_put(sb->s_bdi);
1435 sb->s_bdi = &noop_backing_dev_info;
1436 }
1437 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1438 MINOR(fc->dev), suffix);
1439 if (err)
1440 return err;
1441
1442 /* fuse does it's own writeback accounting */
1443 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1444 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1445
1446 /*
1447 * For a single fuse filesystem use max 1% of dirty +
1448 * writeback threshold.
1449 *
1450 * This gives about 1M of write buffer for memory maps on a
1451 * machine with 1G and 10% dirty_ratio, which should be more
1452 * than enough.
1453 *
1454 * Privileged users can raise it by writing to
1455 *
1456 * /sys/class/bdi/<bdi>/max_ratio
1457 */
1458 bdi_set_max_ratio(sb->s_bdi, 1);
1459
1460 return 0;
1461}
1462
1463struct fuse_dev *fuse_dev_alloc(void)
1464{
1465 struct fuse_dev *fud;
1466 struct list_head *pq;
1467
1468 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1469 if (!fud)
1470 return NULL;
1471
1472 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1473 if (!pq) {
1474 kfree(fud);
1475 return NULL;
1476 }
1477
1478 fud->pq.processing = pq;
1479 fuse_pqueue_init(&fud->pq);
1480
1481 return fud;
1482}
1483EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1484
1485void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1486{
1487 fud->fc = fuse_conn_get(fc);
1488 spin_lock(&fc->lock);
1489 list_add_tail(&fud->entry, &fc->devices);
1490 spin_unlock(&fc->lock);
1491}
1492EXPORT_SYMBOL_GPL(fuse_dev_install);
1493
1494struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1495{
1496 struct fuse_dev *fud;
1497
1498 fud = fuse_dev_alloc();
1499 if (!fud)
1500 return NULL;
1501
1502 fuse_dev_install(fud, fc);
1503 return fud;
1504}
1505EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1506
1507void fuse_dev_free(struct fuse_dev *fud)
1508{
1509 struct fuse_conn *fc = fud->fc;
1510
1511 if (fc) {
1512 spin_lock(&fc->lock);
1513 list_del(&fud->entry);
1514 spin_unlock(&fc->lock);
1515
1516 fuse_conn_put(fc);
1517 }
1518 kfree(fud->pq.processing);
1519 kfree(fud);
1520}
1521EXPORT_SYMBOL_GPL(fuse_dev_free);
1522
1523static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1524 const struct fuse_inode *fi)
1525{
1526 struct timespec64 atime = inode_get_atime(&fi->inode);
1527 struct timespec64 mtime = inode_get_mtime(&fi->inode);
1528 struct timespec64 ctime = inode_get_ctime(&fi->inode);
1529
1530 *attr = (struct fuse_attr){
1531 .ino = fi->inode.i_ino,
1532 .size = fi->inode.i_size,
1533 .blocks = fi->inode.i_blocks,
1534 .atime = atime.tv_sec,
1535 .mtime = mtime.tv_sec,
1536 .ctime = ctime.tv_sec,
1537 .atimensec = atime.tv_nsec,
1538 .mtimensec = mtime.tv_nsec,
1539 .ctimensec = ctime.tv_nsec,
1540 .mode = fi->inode.i_mode,
1541 .nlink = fi->inode.i_nlink,
1542 .uid = __kuid_val(fi->inode.i_uid),
1543 .gid = __kgid_val(fi->inode.i_gid),
1544 .rdev = fi->inode.i_rdev,
1545 .blksize = 1u << fi->inode.i_blkbits,
1546 };
1547}
1548
1549static void fuse_sb_defaults(struct super_block *sb)
1550{
1551 sb->s_magic = FUSE_SUPER_MAGIC;
1552 sb->s_op = &fuse_super_operations;
1553 sb->s_xattr = fuse_xattr_handlers;
1554 sb->s_maxbytes = MAX_LFS_FILESIZE;
1555 sb->s_time_gran = 1;
1556 sb->s_export_op = &fuse_export_operations;
1557 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1558 if (sb->s_user_ns != &init_user_ns)
1559 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1560 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1561}
1562
1563static int fuse_fill_super_submount(struct super_block *sb,
1564 struct fuse_inode *parent_fi)
1565{
1566 struct fuse_mount *fm = get_fuse_mount_super(sb);
1567 struct super_block *parent_sb = parent_fi->inode.i_sb;
1568 struct fuse_attr root_attr;
1569 struct inode *root;
1570 struct fuse_submount_lookup *sl;
1571 struct fuse_inode *fi;
1572
1573 fuse_sb_defaults(sb);
1574 fm->sb = sb;
1575
1576 WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1577 sb->s_bdi = bdi_get(parent_sb->s_bdi);
1578
1579 sb->s_xattr = parent_sb->s_xattr;
1580 sb->s_export_op = parent_sb->s_export_op;
1581 sb->s_time_gran = parent_sb->s_time_gran;
1582 sb->s_blocksize = parent_sb->s_blocksize;
1583 sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1584 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1585 if (parent_sb->s_subtype && !sb->s_subtype)
1586 return -ENOMEM;
1587
1588 fuse_fill_attr_from_inode(&root_attr, parent_fi);
1589 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1590 /*
1591 * This inode is just a duplicate, so it is not looked up and
1592 * its nlookup should not be incremented. fuse_iget() does
1593 * that, though, so undo it here.
1594 */
1595 fi = get_fuse_inode(root);
1596 fi->nlookup--;
1597
1598 sb->s_d_op = &fuse_dentry_operations;
1599 sb->s_root = d_make_root(root);
1600 if (!sb->s_root)
1601 return -ENOMEM;
1602
1603 /*
1604 * Grab the parent's submount_lookup pointer and take a
1605 * reference on the shared nlookup from the parent. This is to
1606 * prevent the last forget for this nodeid from getting
1607 * triggered until all users have finished with it.
1608 */
1609 sl = parent_fi->submount_lookup;
1610 WARN_ON(!sl);
1611 if (sl) {
1612 refcount_inc(&sl->count);
1613 fi->submount_lookup = sl;
1614 }
1615
1616 return 0;
1617}
1618
1619/* Filesystem context private data holds the FUSE inode of the mount point */
1620static int fuse_get_tree_submount(struct fs_context *fsc)
1621{
1622 struct fuse_mount *fm;
1623 struct fuse_inode *mp_fi = fsc->fs_private;
1624 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1625 struct super_block *sb;
1626 int err;
1627
1628 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1629 if (!fm)
1630 return -ENOMEM;
1631
1632 fm->fc = fuse_conn_get(fc);
1633 fsc->s_fs_info = fm;
1634 sb = sget_fc(fsc, NULL, set_anon_super_fc);
1635 if (fsc->s_fs_info)
1636 fuse_mount_destroy(fm);
1637 if (IS_ERR(sb))
1638 return PTR_ERR(sb);
1639
1640 /* Initialize superblock, making @mp_fi its root */
1641 err = fuse_fill_super_submount(sb, mp_fi);
1642 if (err) {
1643 deactivate_locked_super(sb);
1644 return err;
1645 }
1646
1647 down_write(&fc->killsb);
1648 list_add_tail(&fm->fc_entry, &fc->mounts);
1649 up_write(&fc->killsb);
1650
1651 sb->s_flags |= SB_ACTIVE;
1652 fsc->root = dget(sb->s_root);
1653
1654 return 0;
1655}
1656
1657static const struct fs_context_operations fuse_context_submount_ops = {
1658 .get_tree = fuse_get_tree_submount,
1659};
1660
1661int fuse_init_fs_context_submount(struct fs_context *fsc)
1662{
1663 fsc->ops = &fuse_context_submount_ops;
1664 return 0;
1665}
1666EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1667
1668int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1669{
1670 struct fuse_dev *fud = NULL;
1671 struct fuse_mount *fm = get_fuse_mount_super(sb);
1672 struct fuse_conn *fc = fm->fc;
1673 struct inode *root;
1674 struct dentry *root_dentry;
1675 int err;
1676
1677 err = -EINVAL;
1678 if (sb->s_flags & SB_MANDLOCK)
1679 goto err;
1680
1681 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1682 fuse_sb_defaults(sb);
1683
1684 if (ctx->is_bdev) {
1685#ifdef CONFIG_BLOCK
1686 err = -EINVAL;
1687 if (!sb_set_blocksize(sb, ctx->blksize))
1688 goto err;
1689#endif
1690 } else {
1691 sb->s_blocksize = PAGE_SIZE;
1692 sb->s_blocksize_bits = PAGE_SHIFT;
1693 }
1694
1695 sb->s_subtype = ctx->subtype;
1696 ctx->subtype = NULL;
1697 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1698 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev);
1699 if (err)
1700 goto err;
1701 }
1702
1703 if (ctx->fudptr) {
1704 err = -ENOMEM;
1705 fud = fuse_dev_alloc_install(fc);
1706 if (!fud)
1707 goto err_free_dax;
1708 }
1709
1710 fc->dev = sb->s_dev;
1711 fm->sb = sb;
1712 err = fuse_bdi_init(fc, sb);
1713 if (err)
1714 goto err_dev_free;
1715
1716 /* Handle umasking inside the fuse code */
1717 if (sb->s_flags & SB_POSIXACL)
1718 fc->dont_mask = 1;
1719 sb->s_flags |= SB_POSIXACL;
1720
1721 fc->default_permissions = ctx->default_permissions;
1722 fc->allow_other = ctx->allow_other;
1723 fc->user_id = ctx->user_id;
1724 fc->group_id = ctx->group_id;
1725 fc->legacy_opts_show = ctx->legacy_opts_show;
1726 fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1727 fc->destroy = ctx->destroy;
1728 fc->no_control = ctx->no_control;
1729 fc->no_force_umount = ctx->no_force_umount;
1730
1731 err = -ENOMEM;
1732 root = fuse_get_root_inode(sb, ctx->rootmode);
1733 sb->s_d_op = &fuse_root_dentry_operations;
1734 root_dentry = d_make_root(root);
1735 if (!root_dentry)
1736 goto err_dev_free;
1737 /* Root dentry doesn't have .d_revalidate */
1738 sb->s_d_op = &fuse_dentry_operations;
1739
1740 mutex_lock(&fuse_mutex);
1741 err = -EINVAL;
1742 if (ctx->fudptr && *ctx->fudptr)
1743 goto err_unlock;
1744
1745 err = fuse_ctl_add_conn(fc);
1746 if (err)
1747 goto err_unlock;
1748
1749 list_add_tail(&fc->entry, &fuse_conn_list);
1750 sb->s_root = root_dentry;
1751 if (ctx->fudptr)
1752 *ctx->fudptr = fud;
1753 mutex_unlock(&fuse_mutex);
1754 return 0;
1755
1756 err_unlock:
1757 mutex_unlock(&fuse_mutex);
1758 dput(root_dentry);
1759 err_dev_free:
1760 if (fud)
1761 fuse_dev_free(fud);
1762 err_free_dax:
1763 if (IS_ENABLED(CONFIG_FUSE_DAX))
1764 fuse_dax_conn_free(fc);
1765 err:
1766 return err;
1767}
1768EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1769
1770static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1771{
1772 struct fuse_fs_context *ctx = fsc->fs_private;
1773 int err;
1774
1775 if (!ctx->file || !ctx->rootmode_present ||
1776 !ctx->user_id_present || !ctx->group_id_present)
1777 return -EINVAL;
1778
1779 /*
1780 * Require mount to happen from the same user namespace which
1781 * opened /dev/fuse to prevent potential attacks.
1782 */
1783 if ((ctx->file->f_op != &fuse_dev_operations) ||
1784 (ctx->file->f_cred->user_ns != sb->s_user_ns))
1785 return -EINVAL;
1786 ctx->fudptr = &ctx->file->private_data;
1787
1788 err = fuse_fill_super_common(sb, ctx);
1789 if (err)
1790 return err;
1791 /* file->private_data shall be visible on all CPUs after this */
1792 smp_mb();
1793 fuse_send_init(get_fuse_mount_super(sb));
1794 return 0;
1795}
1796
1797/*
1798 * This is the path where user supplied an already initialized fuse dev. In
1799 * this case never create a new super if the old one is gone.
1800 */
1801static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1802{
1803 return -ENOTCONN;
1804}
1805
1806static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1807{
1808
1809 return fsc->sget_key == get_fuse_conn_super(sb);
1810}
1811
1812static int fuse_get_tree(struct fs_context *fsc)
1813{
1814 struct fuse_fs_context *ctx = fsc->fs_private;
1815 struct fuse_dev *fud;
1816 struct fuse_conn *fc;
1817 struct fuse_mount *fm;
1818 struct super_block *sb;
1819 int err;
1820
1821 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1822 if (!fc)
1823 return -ENOMEM;
1824
1825 fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1826 if (!fm) {
1827 kfree(fc);
1828 return -ENOMEM;
1829 }
1830
1831 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1832 fc->release = fuse_free_conn;
1833
1834 fsc->s_fs_info = fm;
1835
1836 if (ctx->fd_present)
1837 ctx->file = fget(ctx->fd);
1838
1839 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1840 err = get_tree_bdev(fsc, fuse_fill_super);
1841 goto out;
1842 }
1843 /*
1844 * While block dev mount can be initialized with a dummy device fd
1845 * (found by device name), normal fuse mounts can't
1846 */
1847 err = -EINVAL;
1848 if (!ctx->file)
1849 goto out;
1850
1851 /*
1852 * Allow creating a fuse mount with an already initialized fuse
1853 * connection
1854 */
1855 fud = READ_ONCE(ctx->file->private_data);
1856 if (ctx->file->f_op == &fuse_dev_operations && fud) {
1857 fsc->sget_key = fud->fc;
1858 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1859 err = PTR_ERR_OR_ZERO(sb);
1860 if (!IS_ERR(sb))
1861 fsc->root = dget(sb->s_root);
1862 } else {
1863 err = get_tree_nodev(fsc, fuse_fill_super);
1864 }
1865out:
1866 if (fsc->s_fs_info)
1867 fuse_mount_destroy(fm);
1868 if (ctx->file)
1869 fput(ctx->file);
1870 return err;
1871}
1872
1873static const struct fs_context_operations fuse_context_ops = {
1874 .free = fuse_free_fsc,
1875 .parse_param = fuse_parse_param,
1876 .reconfigure = fuse_reconfigure,
1877 .get_tree = fuse_get_tree,
1878};
1879
1880/*
1881 * Set up the filesystem mount context.
1882 */
1883static int fuse_init_fs_context(struct fs_context *fsc)
1884{
1885 struct fuse_fs_context *ctx;
1886
1887 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1888 if (!ctx)
1889 return -ENOMEM;
1890
1891 ctx->max_read = ~0;
1892 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1893 ctx->legacy_opts_show = true;
1894
1895#ifdef CONFIG_BLOCK
1896 if (fsc->fs_type == &fuseblk_fs_type) {
1897 ctx->is_bdev = true;
1898 ctx->destroy = true;
1899 }
1900#endif
1901
1902 fsc->fs_private = ctx;
1903 fsc->ops = &fuse_context_ops;
1904 return 0;
1905}
1906
1907bool fuse_mount_remove(struct fuse_mount *fm)
1908{
1909 struct fuse_conn *fc = fm->fc;
1910 bool last = false;
1911
1912 down_write(&fc->killsb);
1913 list_del_init(&fm->fc_entry);
1914 if (list_empty(&fc->mounts))
1915 last = true;
1916 up_write(&fc->killsb);
1917
1918 return last;
1919}
1920EXPORT_SYMBOL_GPL(fuse_mount_remove);
1921
1922void fuse_conn_destroy(struct fuse_mount *fm)
1923{
1924 struct fuse_conn *fc = fm->fc;
1925
1926 if (fc->destroy)
1927 fuse_send_destroy(fm);
1928
1929 fuse_abort_conn(fc);
1930 fuse_wait_aborted(fc);
1931
1932 if (!list_empty(&fc->entry)) {
1933 mutex_lock(&fuse_mutex);
1934 list_del(&fc->entry);
1935 fuse_ctl_remove_conn(fc);
1936 mutex_unlock(&fuse_mutex);
1937 }
1938}
1939EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1940
1941static void fuse_sb_destroy(struct super_block *sb)
1942{
1943 struct fuse_mount *fm = get_fuse_mount_super(sb);
1944 bool last;
1945
1946 if (sb->s_root) {
1947 last = fuse_mount_remove(fm);
1948 if (last)
1949 fuse_conn_destroy(fm);
1950 }
1951}
1952
1953void fuse_mount_destroy(struct fuse_mount *fm)
1954{
1955 fuse_conn_put(fm->fc);
1956 kfree_rcu(fm, rcu);
1957}
1958EXPORT_SYMBOL(fuse_mount_destroy);
1959
1960static void fuse_kill_sb_anon(struct super_block *sb)
1961{
1962 fuse_sb_destroy(sb);
1963 kill_anon_super(sb);
1964 fuse_mount_destroy(get_fuse_mount_super(sb));
1965}
1966
1967static struct file_system_type fuse_fs_type = {
1968 .owner = THIS_MODULE,
1969 .name = "fuse",
1970 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1971 .init_fs_context = fuse_init_fs_context,
1972 .parameters = fuse_fs_parameters,
1973 .kill_sb = fuse_kill_sb_anon,
1974};
1975MODULE_ALIAS_FS("fuse");
1976
1977#ifdef CONFIG_BLOCK
1978static void fuse_kill_sb_blk(struct super_block *sb)
1979{
1980 fuse_sb_destroy(sb);
1981 kill_block_super(sb);
1982 fuse_mount_destroy(get_fuse_mount_super(sb));
1983}
1984
1985static struct file_system_type fuseblk_fs_type = {
1986 .owner = THIS_MODULE,
1987 .name = "fuseblk",
1988 .init_fs_context = fuse_init_fs_context,
1989 .parameters = fuse_fs_parameters,
1990 .kill_sb = fuse_kill_sb_blk,
1991 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1992};
1993MODULE_ALIAS_FS("fuseblk");
1994
1995static inline int register_fuseblk(void)
1996{
1997 return register_filesystem(&fuseblk_fs_type);
1998}
1999
2000static inline void unregister_fuseblk(void)
2001{
2002 unregister_filesystem(&fuseblk_fs_type);
2003}
2004#else
2005static inline int register_fuseblk(void)
2006{
2007 return 0;
2008}
2009
2010static inline void unregister_fuseblk(void)
2011{
2012}
2013#endif
2014
2015static void fuse_inode_init_once(void *foo)
2016{
2017 struct inode *inode = foo;
2018
2019 inode_init_once(inode);
2020}
2021
2022static int __init fuse_fs_init(void)
2023{
2024 int err;
2025
2026 fuse_inode_cachep = kmem_cache_create("fuse_inode",
2027 sizeof(struct fuse_inode), 0,
2028 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
2029 fuse_inode_init_once);
2030 err = -ENOMEM;
2031 if (!fuse_inode_cachep)
2032 goto out;
2033
2034 err = register_fuseblk();
2035 if (err)
2036 goto out2;
2037
2038 err = register_filesystem(&fuse_fs_type);
2039 if (err)
2040 goto out3;
2041
2042 return 0;
2043
2044 out3:
2045 unregister_fuseblk();
2046 out2:
2047 kmem_cache_destroy(fuse_inode_cachep);
2048 out:
2049 return err;
2050}
2051
2052static void fuse_fs_cleanup(void)
2053{
2054 unregister_filesystem(&fuse_fs_type);
2055 unregister_fuseblk();
2056
2057 /*
2058 * Make sure all delayed rcu free inodes are flushed before we
2059 * destroy cache.
2060 */
2061 rcu_barrier();
2062 kmem_cache_destroy(fuse_inode_cachep);
2063}
2064
2065static struct kobject *fuse_kobj;
2066
2067static int fuse_sysfs_init(void)
2068{
2069 int err;
2070
2071 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
2072 if (!fuse_kobj) {
2073 err = -ENOMEM;
2074 goto out_err;
2075 }
2076
2077 err = sysfs_create_mount_point(fuse_kobj, "connections");
2078 if (err)
2079 goto out_fuse_unregister;
2080
2081 return 0;
2082
2083 out_fuse_unregister:
2084 kobject_put(fuse_kobj);
2085 out_err:
2086 return err;
2087}
2088
2089static void fuse_sysfs_cleanup(void)
2090{
2091 sysfs_remove_mount_point(fuse_kobj, "connections");
2092 kobject_put(fuse_kobj);
2093}
2094
2095static int __init fuse_init(void)
2096{
2097 int res;
2098
2099 pr_info("init (API version %i.%i)\n",
2100 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
2101
2102 INIT_LIST_HEAD(&fuse_conn_list);
2103 res = fuse_fs_init();
2104 if (res)
2105 goto err;
2106
2107 res = fuse_dev_init();
2108 if (res)
2109 goto err_fs_cleanup;
2110
2111 res = fuse_sysfs_init();
2112 if (res)
2113 goto err_dev_cleanup;
2114
2115 res = fuse_ctl_init();
2116 if (res)
2117 goto err_sysfs_cleanup;
2118
2119 sanitize_global_limit(&max_user_bgreq);
2120 sanitize_global_limit(&max_user_congthresh);
2121
2122 return 0;
2123
2124 err_sysfs_cleanup:
2125 fuse_sysfs_cleanup();
2126 err_dev_cleanup:
2127 fuse_dev_cleanup();
2128 err_fs_cleanup:
2129 fuse_fs_cleanup();
2130 err:
2131 return res;
2132}
2133
2134static void __exit fuse_exit(void)
2135{
2136 pr_debug("exit\n");
2137
2138 fuse_ctl_cleanup();
2139 fuse_sysfs_cleanup();
2140 fuse_fs_cleanup();
2141 fuse_dev_cleanup();
2142}
2143
2144module_init(fuse_init);
2145module_exit(fuse_exit);