inode.c revision 660585b5
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	init_rwsem(&fi->i_mmap_sem);
89	spin_lock_init(&fi->lock);
90	fi->forget = fuse_alloc_forget();
91	if (!fi->forget)
92		goto out_free;
93
94	if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
95		goto out_free_forget;
96
97	return &fi->inode;
98
99out_free_forget:
100	kfree(fi->forget);
101out_free:
102	kmem_cache_free(fuse_inode_cachep, fi);
103	return NULL;
104}
105
106static void fuse_free_inode(struct inode *inode)
107{
108	struct fuse_inode *fi = get_fuse_inode(inode);
109
110	mutex_destroy(&fi->mutex);
111	kfree(fi->forget);
112#ifdef CONFIG_FUSE_DAX
113	kfree(fi->dax);
114#endif
115	kmem_cache_free(fuse_inode_cachep, fi);
116}
117
118static void fuse_evict_inode(struct inode *inode)
119{
120	struct fuse_inode *fi = get_fuse_inode(inode);
121
122	truncate_inode_pages_final(&inode->i_data);
123	clear_inode(inode);
124	if (inode->i_sb->s_flags & SB_ACTIVE) {
125		struct fuse_conn *fc = get_fuse_conn(inode);
126
127		if (FUSE_IS_DAX(inode))
128			fuse_dax_inode_cleanup(inode);
129		if (fi->nlookup) {
130			fuse_queue_forget(fc, fi->forget, fi->nodeid,
131					  fi->nlookup);
132			fi->forget = NULL;
133		}
134	}
135	if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
136		WARN_ON(!list_empty(&fi->write_files));
137		WARN_ON(!list_empty(&fi->queued_writes));
138	}
139}
140
141static int fuse_reconfigure(struct fs_context *fsc)
142{
143	struct super_block *sb = fsc->root->d_sb;
144
145	sync_filesystem(sb);
146	if (fsc->sb_flags & SB_MANDLOCK)
147		return -EINVAL;
148
149	return 0;
150}
151
152/*
153 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
154 * so that it will fit.
155 */
156static ino_t fuse_squash_ino(u64 ino64)
157{
158	ino_t ino = (ino_t) ino64;
159	if (sizeof(ino_t) < sizeof(u64))
160		ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
161	return ino;
162}
163
164void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
165				   u64 attr_valid)
166{
167	struct fuse_conn *fc = get_fuse_conn(inode);
168	struct fuse_inode *fi = get_fuse_inode(inode);
169
170	lockdep_assert_held(&fi->lock);
171
172	fi->attr_version = atomic64_inc_return(&fc->attr_version);
173	fi->i_time = attr_valid;
174	WRITE_ONCE(fi->inval_mask, 0);
175
176	inode->i_ino     = fuse_squash_ino(attr->ino);
177	inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
178	set_nlink(inode, attr->nlink);
179	inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
180	inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
181	inode->i_blocks  = attr->blocks;
182	inode->i_atime.tv_sec   = attr->atime;
183	inode->i_atime.tv_nsec  = attr->atimensec;
184	/* mtime from server may be stale due to local buffered write */
185	if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
186		inode->i_mtime.tv_sec   = attr->mtime;
187		inode->i_mtime.tv_nsec  = attr->mtimensec;
188		inode->i_ctime.tv_sec   = attr->ctime;
189		inode->i_ctime.tv_nsec  = attr->ctimensec;
190	}
191
192	if (attr->blksize != 0)
193		inode->i_blkbits = ilog2(attr->blksize);
194	else
195		inode->i_blkbits = inode->i_sb->s_blocksize_bits;
196
197	/*
198	 * Don't set the sticky bit in i_mode, unless we want the VFS
199	 * to check permissions.  This prevents failures due to the
200	 * check in may_delete().
201	 */
202	fi->orig_i_mode = inode->i_mode;
203	if (!fc->default_permissions)
204		inode->i_mode &= ~S_ISVTX;
205
206	fi->orig_ino = attr->ino;
207
208	/*
209	 * We are refreshing inode data and it is possible that another
210	 * client set suid/sgid or security.capability xattr. So clear
211	 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
212	 * was set or if security.capability xattr was set. But we don't
213	 * know if security.capability has been set or not. So clear it
214	 * anyway. Its less efficient but should be safe.
215	 */
216	inode->i_flags &= ~S_NOSEC;
217}
218
219void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
220			    u64 attr_valid, u64 attr_version)
221{
222	struct fuse_conn *fc = get_fuse_conn(inode);
223	struct fuse_inode *fi = get_fuse_inode(inode);
224	bool is_wb = fc->writeback_cache;
225	loff_t oldsize;
226	struct timespec64 old_mtime;
227
228	spin_lock(&fi->lock);
229	if ((attr_version != 0 && fi->attr_version > attr_version) ||
230	    test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
231		spin_unlock(&fi->lock);
232		return;
233	}
234
235	old_mtime = inode->i_mtime;
236	fuse_change_attributes_common(inode, attr, attr_valid);
237
238	oldsize = inode->i_size;
239	/*
240	 * In case of writeback_cache enabled, the cached writes beyond EOF
241	 * extend local i_size without keeping userspace server in sync. So,
242	 * attr->size coming from server can be stale. We cannot trust it.
243	 */
244	if (!is_wb || !S_ISREG(inode->i_mode))
245		i_size_write(inode, attr->size);
246	spin_unlock(&fi->lock);
247
248	if (!is_wb && S_ISREG(inode->i_mode)) {
249		bool inval = false;
250
251		if (oldsize != attr->size) {
252			truncate_pagecache(inode, attr->size);
253			if (!fc->explicit_inval_data)
254				inval = true;
255		} else if (fc->auto_inval_data) {
256			struct timespec64 new_mtime = {
257				.tv_sec = attr->mtime,
258				.tv_nsec = attr->mtimensec,
259			};
260
261			/*
262			 * Auto inval mode also checks and invalidates if mtime
263			 * has changed.
264			 */
265			if (!timespec64_equal(&old_mtime, &new_mtime))
266				inval = true;
267		}
268
269		if (inval)
270			invalidate_inode_pages2(inode->i_mapping);
271	}
272}
273
274static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
275{
276	inode->i_mode = attr->mode & S_IFMT;
277	inode->i_size = attr->size;
278	inode->i_mtime.tv_sec  = attr->mtime;
279	inode->i_mtime.tv_nsec = attr->mtimensec;
280	inode->i_ctime.tv_sec  = attr->ctime;
281	inode->i_ctime.tv_nsec = attr->ctimensec;
282	if (S_ISREG(inode->i_mode)) {
283		fuse_init_common(inode);
284		fuse_init_file_inode(inode);
285	} else if (S_ISDIR(inode->i_mode))
286		fuse_init_dir(inode);
287	else if (S_ISLNK(inode->i_mode))
288		fuse_init_symlink(inode);
289	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
290		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
291		fuse_init_common(inode);
292		init_special_inode(inode, inode->i_mode,
293				   new_decode_dev(attr->rdev));
294	} else
295		BUG();
296}
297
298static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
299{
300	u64 nodeid = *(u64 *) _nodeidp;
301	if (get_node_id(inode) == nodeid)
302		return 1;
303	else
304		return 0;
305}
306
307static int fuse_inode_set(struct inode *inode, void *_nodeidp)
308{
309	u64 nodeid = *(u64 *) _nodeidp;
310	get_fuse_inode(inode)->nodeid = nodeid;
311	return 0;
312}
313
314struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
315			int generation, struct fuse_attr *attr,
316			u64 attr_valid, u64 attr_version)
317{
318	struct inode *inode;
319	struct fuse_inode *fi;
320	struct fuse_conn *fc = get_fuse_conn_super(sb);
321
322	/*
323	 * Auto mount points get their node id from the submount root, which is
324	 * not a unique identifier within this filesystem.
325	 *
326	 * To avoid conflicts, do not place submount points into the inode hash
327	 * table.
328	 */
329	if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
330	    S_ISDIR(attr->mode)) {
331		inode = new_inode(sb);
332		if (!inode)
333			return NULL;
334
335		fuse_init_inode(inode, attr);
336		get_fuse_inode(inode)->nodeid = nodeid;
337		inode->i_flags |= S_AUTOMOUNT;
338		goto done;
339	}
340
341retry:
342	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
343	if (!inode)
344		return NULL;
345
346	if ((inode->i_state & I_NEW)) {
347		inode->i_flags |= S_NOATIME;
348		if (!fc->writeback_cache || !S_ISREG(attr->mode))
349			inode->i_flags |= S_NOCMTIME;
350		inode->i_generation = generation;
351		fuse_init_inode(inode, attr);
352		unlock_new_inode(inode);
353	} else if (fuse_stale_inode(inode, generation, attr)) {
354		/* nodeid was reused, any I/O on the old inode should fail */
355		fuse_make_bad(inode);
356		iput(inode);
357		goto retry;
358	}
359done:
360	fi = get_fuse_inode(inode);
361	spin_lock(&fi->lock);
362	fi->nlookup++;
363	spin_unlock(&fi->lock);
364	fuse_change_attributes(inode, attr, attr_valid, attr_version);
365
366	return inode;
367}
368
369struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
370			   struct fuse_mount **fm)
371{
372	struct fuse_mount *fm_iter;
373	struct inode *inode;
374
375	WARN_ON(!rwsem_is_locked(&fc->killsb));
376	list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
377		if (!fm_iter->sb)
378			continue;
379
380		inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
381		if (inode) {
382			if (fm)
383				*fm = fm_iter;
384			return inode;
385		}
386	}
387
388	return NULL;
389}
390
391int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
392			     loff_t offset, loff_t len)
393{
394	struct fuse_inode *fi;
395	struct inode *inode;
396	pgoff_t pg_start;
397	pgoff_t pg_end;
398
399	inode = fuse_ilookup(fc, nodeid, NULL);
400	if (!inode)
401		return -ENOENT;
402
403	fi = get_fuse_inode(inode);
404	spin_lock(&fi->lock);
405	fi->attr_version = atomic64_inc_return(&fc->attr_version);
406	spin_unlock(&fi->lock);
407
408	fuse_invalidate_attr(inode);
409	forget_all_cached_acls(inode);
410	if (offset >= 0) {
411		pg_start = offset >> PAGE_SHIFT;
412		if (len <= 0)
413			pg_end = -1;
414		else
415			pg_end = (offset + len - 1) >> PAGE_SHIFT;
416		invalidate_inode_pages2_range(inode->i_mapping,
417					      pg_start, pg_end);
418	}
419	iput(inode);
420	return 0;
421}
422
423bool fuse_lock_inode(struct inode *inode)
424{
425	bool locked = false;
426
427	if (!get_fuse_conn(inode)->parallel_dirops) {
428		mutex_lock(&get_fuse_inode(inode)->mutex);
429		locked = true;
430	}
431
432	return locked;
433}
434
435void fuse_unlock_inode(struct inode *inode, bool locked)
436{
437	if (locked)
438		mutex_unlock(&get_fuse_inode(inode)->mutex);
439}
440
441static void fuse_umount_begin(struct super_block *sb)
442{
443	struct fuse_conn *fc = get_fuse_conn_super(sb);
444
445	if (!fc->no_force_umount)
446		fuse_abort_conn(fc);
447}
448
449static void fuse_send_destroy(struct fuse_mount *fm)
450{
451	if (fm->fc->conn_init) {
452		FUSE_ARGS(args);
453
454		args.opcode = FUSE_DESTROY;
455		args.force = true;
456		args.nocreds = true;
457		fuse_simple_request(fm, &args);
458	}
459}
460
461static void fuse_put_super(struct super_block *sb)
462{
463	struct fuse_mount *fm = get_fuse_mount_super(sb);
464
465	fuse_conn_put(fm->fc);
466	kfree(fm);
467}
468
469static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
470{
471	stbuf->f_type    = FUSE_SUPER_MAGIC;
472	stbuf->f_bsize   = attr->bsize;
473	stbuf->f_frsize  = attr->frsize;
474	stbuf->f_blocks  = attr->blocks;
475	stbuf->f_bfree   = attr->bfree;
476	stbuf->f_bavail  = attr->bavail;
477	stbuf->f_files   = attr->files;
478	stbuf->f_ffree   = attr->ffree;
479	stbuf->f_namelen = attr->namelen;
480	/* fsid is left zero */
481}
482
483static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
484{
485	struct super_block *sb = dentry->d_sb;
486	struct fuse_mount *fm = get_fuse_mount_super(sb);
487	FUSE_ARGS(args);
488	struct fuse_statfs_out outarg;
489	int err;
490
491	if (!fuse_allow_current_process(fm->fc)) {
492		buf->f_type = FUSE_SUPER_MAGIC;
493		return 0;
494	}
495
496	memset(&outarg, 0, sizeof(outarg));
497	args.in_numargs = 0;
498	args.opcode = FUSE_STATFS;
499	args.nodeid = get_node_id(d_inode(dentry));
500	args.out_numargs = 1;
501	args.out_args[0].size = sizeof(outarg);
502	args.out_args[0].value = &outarg;
503	err = fuse_simple_request(fm, &args);
504	if (!err)
505		convert_fuse_statfs(buf, &outarg.st);
506	return err;
507}
508
509static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
510{
511	struct fuse_sync_bucket *bucket;
512
513	bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
514	if (bucket) {
515		init_waitqueue_head(&bucket->waitq);
516		/* Initial active count */
517		atomic_set(&bucket->count, 1);
518	}
519	return bucket;
520}
521
522static void fuse_sync_fs_writes(struct fuse_conn *fc)
523{
524	struct fuse_sync_bucket *bucket, *new_bucket;
525	int count;
526
527	new_bucket = fuse_sync_bucket_alloc();
528	spin_lock(&fc->lock);
529	bucket = rcu_dereference_protected(fc->curr_bucket, 1);
530	count = atomic_read(&bucket->count);
531	WARN_ON(count < 1);
532	/* No outstanding writes? */
533	if (count == 1) {
534		spin_unlock(&fc->lock);
535		kfree(new_bucket);
536		return;
537	}
538
539	/*
540	 * Completion of new bucket depends on completion of this bucket, so add
541	 * one more count.
542	 */
543	atomic_inc(&new_bucket->count);
544	rcu_assign_pointer(fc->curr_bucket, new_bucket);
545	spin_unlock(&fc->lock);
546	/*
547	 * Drop initial active count.  At this point if all writes in this and
548	 * ancestor buckets complete, the count will go to zero and this task
549	 * will be woken up.
550	 */
551	atomic_dec(&bucket->count);
552
553	wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
554
555	/* Drop temp count on descendant bucket */
556	fuse_sync_bucket_dec(new_bucket);
557	kfree_rcu(bucket, rcu);
558}
559
560static int fuse_sync_fs(struct super_block *sb, int wait)
561{
562	struct fuse_mount *fm = get_fuse_mount_super(sb);
563	struct fuse_conn *fc = fm->fc;
564	struct fuse_syncfs_in inarg;
565	FUSE_ARGS(args);
566	int err;
567
568	/*
569	 * Userspace cannot handle the wait == 0 case.  Avoid a
570	 * gratuitous roundtrip.
571	 */
572	if (!wait)
573		return 0;
574
575	/* The filesystem is being unmounted.  Nothing to do. */
576	if (!sb->s_root)
577		return 0;
578
579	if (!fc->sync_fs)
580		return 0;
581
582	fuse_sync_fs_writes(fc);
583
584	memset(&inarg, 0, sizeof(inarg));
585	args.in_numargs = 1;
586	args.in_args[0].size = sizeof(inarg);
587	args.in_args[0].value = &inarg;
588	args.opcode = FUSE_SYNCFS;
589	args.nodeid = get_node_id(sb->s_root->d_inode);
590	args.out_numargs = 0;
591
592	err = fuse_simple_request(fm, &args);
593	if (err == -ENOSYS) {
594		fc->sync_fs = 0;
595		err = 0;
596	}
597
598	return err;
599}
600
601enum {
602	OPT_SOURCE,
603	OPT_SUBTYPE,
604	OPT_FD,
605	OPT_ROOTMODE,
606	OPT_USER_ID,
607	OPT_GROUP_ID,
608	OPT_DEFAULT_PERMISSIONS,
609	OPT_ALLOW_OTHER,
610	OPT_MAX_READ,
611	OPT_BLKSIZE,
612	OPT_ERR
613};
614
615static const struct fs_parameter_spec fuse_fs_parameters[] = {
616	fsparam_string	("source",		OPT_SOURCE),
617	fsparam_u32	("fd",			OPT_FD),
618	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
619	fsparam_u32	("user_id",		OPT_USER_ID),
620	fsparam_u32	("group_id",		OPT_GROUP_ID),
621	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
622	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
623	fsparam_u32	("max_read",		OPT_MAX_READ),
624	fsparam_u32	("blksize",		OPT_BLKSIZE),
625	fsparam_string	("subtype",		OPT_SUBTYPE),
626	{}
627};
628
629static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
630{
631	struct fs_parse_result result;
632	struct fuse_fs_context *ctx = fsc->fs_private;
633	int opt;
634
635	if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
636		/*
637		 * Ignore options coming from mount(MS_REMOUNT) for backward
638		 * compatibility.
639		 */
640		if (fsc->oldapi)
641			return 0;
642
643		return invalfc(fsc, "No changes allowed in reconfigure");
644	}
645
646	opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
647	if (opt < 0)
648		return opt;
649
650	switch (opt) {
651	case OPT_SOURCE:
652		if (fsc->source)
653			return invalfc(fsc, "Multiple sources specified");
654		fsc->source = param->string;
655		param->string = NULL;
656		break;
657
658	case OPT_SUBTYPE:
659		if (ctx->subtype)
660			return invalfc(fsc, "Multiple subtypes specified");
661		ctx->subtype = param->string;
662		param->string = NULL;
663		return 0;
664
665	case OPT_FD:
666		ctx->fd = result.uint_32;
667		ctx->fd_present = true;
668		break;
669
670	case OPT_ROOTMODE:
671		if (!fuse_valid_type(result.uint_32))
672			return invalfc(fsc, "Invalid rootmode");
673		ctx->rootmode = result.uint_32;
674		ctx->rootmode_present = true;
675		break;
676
677	case OPT_USER_ID:
678		ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
679		if (!uid_valid(ctx->user_id))
680			return invalfc(fsc, "Invalid user_id");
681		ctx->user_id_present = true;
682		break;
683
684	case OPT_GROUP_ID:
685		ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
686		if (!gid_valid(ctx->group_id))
687			return invalfc(fsc, "Invalid group_id");
688		ctx->group_id_present = true;
689		break;
690
691	case OPT_DEFAULT_PERMISSIONS:
692		ctx->default_permissions = true;
693		break;
694
695	case OPT_ALLOW_OTHER:
696		ctx->allow_other = true;
697		break;
698
699	case OPT_MAX_READ:
700		ctx->max_read = result.uint_32;
701		break;
702
703	case OPT_BLKSIZE:
704		if (!ctx->is_bdev)
705			return invalfc(fsc, "blksize only supported for fuseblk");
706		ctx->blksize = result.uint_32;
707		break;
708
709	default:
710		return -EINVAL;
711	}
712
713	return 0;
714}
715
716static void fuse_free_fsc(struct fs_context *fsc)
717{
718	struct fuse_fs_context *ctx = fsc->fs_private;
719
720	if (ctx) {
721		kfree(ctx->subtype);
722		kfree(ctx);
723	}
724}
725
726static int fuse_show_options(struct seq_file *m, struct dentry *root)
727{
728	struct super_block *sb = root->d_sb;
729	struct fuse_conn *fc = get_fuse_conn_super(sb);
730
731	if (fc->legacy_opts_show) {
732		seq_printf(m, ",user_id=%u",
733			   from_kuid_munged(fc->user_ns, fc->user_id));
734		seq_printf(m, ",group_id=%u",
735			   from_kgid_munged(fc->user_ns, fc->group_id));
736		if (fc->default_permissions)
737			seq_puts(m, ",default_permissions");
738		if (fc->allow_other)
739			seq_puts(m, ",allow_other");
740		if (fc->max_read != ~0)
741			seq_printf(m, ",max_read=%u", fc->max_read);
742		if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
743			seq_printf(m, ",blksize=%lu", sb->s_blocksize);
744	}
745#ifdef CONFIG_FUSE_DAX
746	if (fc->dax)
747		seq_puts(m, ",dax");
748#endif
749
750	return 0;
751}
752
753static void fuse_iqueue_init(struct fuse_iqueue *fiq,
754			     const struct fuse_iqueue_ops *ops,
755			     void *priv)
756{
757	memset(fiq, 0, sizeof(struct fuse_iqueue));
758	spin_lock_init(&fiq->lock);
759	init_waitqueue_head(&fiq->waitq);
760	INIT_LIST_HEAD(&fiq->pending);
761	INIT_LIST_HEAD(&fiq->interrupts);
762	fiq->forget_list_tail = &fiq->forget_list_head;
763	fiq->connected = 1;
764	fiq->ops = ops;
765	fiq->priv = priv;
766}
767
768static void fuse_pqueue_init(struct fuse_pqueue *fpq)
769{
770	unsigned int i;
771
772	spin_lock_init(&fpq->lock);
773	for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
774		INIT_LIST_HEAD(&fpq->processing[i]);
775	INIT_LIST_HEAD(&fpq->io);
776	fpq->connected = 1;
777}
778
779void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
780		    struct user_namespace *user_ns,
781		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
782{
783	memset(fc, 0, sizeof(*fc));
784	spin_lock_init(&fc->lock);
785	spin_lock_init(&fc->bg_lock);
786	init_rwsem(&fc->killsb);
787	refcount_set(&fc->count, 1);
788	atomic_set(&fc->dev_count, 1);
789	init_waitqueue_head(&fc->blocked_waitq);
790	fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
791	INIT_LIST_HEAD(&fc->bg_queue);
792	INIT_LIST_HEAD(&fc->entry);
793	INIT_LIST_HEAD(&fc->devices);
794	atomic_set(&fc->num_waiting, 0);
795	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
796	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
797	atomic64_set(&fc->khctr, 0);
798	fc->polled_files = RB_ROOT;
799	fc->blocked = 0;
800	fc->initialized = 0;
801	fc->connected = 1;
802	atomic64_set(&fc->attr_version, 1);
803	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
804	fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
805	fc->user_ns = get_user_ns(user_ns);
806	fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
807	fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
808
809	INIT_LIST_HEAD(&fc->mounts);
810	list_add(&fm->fc_entry, &fc->mounts);
811	fm->fc = fc;
812}
813EXPORT_SYMBOL_GPL(fuse_conn_init);
814
815void fuse_conn_put(struct fuse_conn *fc)
816{
817	if (refcount_dec_and_test(&fc->count)) {
818		struct fuse_iqueue *fiq = &fc->iq;
819		struct fuse_sync_bucket *bucket;
820
821		if (IS_ENABLED(CONFIG_FUSE_DAX))
822			fuse_dax_conn_free(fc);
823		if (fiq->ops->release)
824			fiq->ops->release(fiq);
825		put_pid_ns(fc->pid_ns);
826		put_user_ns(fc->user_ns);
827		bucket = rcu_dereference_protected(fc->curr_bucket, 1);
828		if (bucket) {
829			WARN_ON(atomic_read(&bucket->count) != 1);
830			kfree(bucket);
831		}
832		fc->release(fc);
833	}
834}
835EXPORT_SYMBOL_GPL(fuse_conn_put);
836
837struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
838{
839	refcount_inc(&fc->count);
840	return fc;
841}
842EXPORT_SYMBOL_GPL(fuse_conn_get);
843
844static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
845{
846	struct fuse_attr attr;
847	memset(&attr, 0, sizeof(attr));
848
849	attr.mode = mode;
850	attr.ino = FUSE_ROOT_ID;
851	attr.nlink = 1;
852	return fuse_iget(sb, 1, 0, &attr, 0, 0);
853}
854
855struct fuse_inode_handle {
856	u64 nodeid;
857	u32 generation;
858};
859
860static struct dentry *fuse_get_dentry(struct super_block *sb,
861				      struct fuse_inode_handle *handle)
862{
863	struct fuse_conn *fc = get_fuse_conn_super(sb);
864	struct inode *inode;
865	struct dentry *entry;
866	int err = -ESTALE;
867
868	if (handle->nodeid == 0)
869		goto out_err;
870
871	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
872	if (!inode) {
873		struct fuse_entry_out outarg;
874		const struct qstr name = QSTR_INIT(".", 1);
875
876		if (!fc->export_support)
877			goto out_err;
878
879		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
880				       &inode);
881		if (err && err != -ENOENT)
882			goto out_err;
883		if (err || !inode) {
884			err = -ESTALE;
885			goto out_err;
886		}
887		err = -EIO;
888		if (get_node_id(inode) != handle->nodeid)
889			goto out_iput;
890	}
891	err = -ESTALE;
892	if (inode->i_generation != handle->generation)
893		goto out_iput;
894
895	entry = d_obtain_alias(inode);
896	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
897		fuse_invalidate_entry_cache(entry);
898
899	return entry;
900
901 out_iput:
902	iput(inode);
903 out_err:
904	return ERR_PTR(err);
905}
906
907static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
908			   struct inode *parent)
909{
910	int len = parent ? 6 : 3;
911	u64 nodeid;
912	u32 generation;
913
914	if (*max_len < len) {
915		*max_len = len;
916		return  FILEID_INVALID;
917	}
918
919	nodeid = get_fuse_inode(inode)->nodeid;
920	generation = inode->i_generation;
921
922	fh[0] = (u32)(nodeid >> 32);
923	fh[1] = (u32)(nodeid & 0xffffffff);
924	fh[2] = generation;
925
926	if (parent) {
927		nodeid = get_fuse_inode(parent)->nodeid;
928		generation = parent->i_generation;
929
930		fh[3] = (u32)(nodeid >> 32);
931		fh[4] = (u32)(nodeid & 0xffffffff);
932		fh[5] = generation;
933	}
934
935	*max_len = len;
936	return parent ? 0x82 : 0x81;
937}
938
939static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
940		struct fid *fid, int fh_len, int fh_type)
941{
942	struct fuse_inode_handle handle;
943
944	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
945		return NULL;
946
947	handle.nodeid = (u64) fid->raw[0] << 32;
948	handle.nodeid |= (u64) fid->raw[1];
949	handle.generation = fid->raw[2];
950	return fuse_get_dentry(sb, &handle);
951}
952
953static struct dentry *fuse_fh_to_parent(struct super_block *sb,
954		struct fid *fid, int fh_len, int fh_type)
955{
956	struct fuse_inode_handle parent;
957
958	if (fh_type != 0x82 || fh_len < 6)
959		return NULL;
960
961	parent.nodeid = (u64) fid->raw[3] << 32;
962	parent.nodeid |= (u64) fid->raw[4];
963	parent.generation = fid->raw[5];
964	return fuse_get_dentry(sb, &parent);
965}
966
967static struct dentry *fuse_get_parent(struct dentry *child)
968{
969	struct inode *child_inode = d_inode(child);
970	struct fuse_conn *fc = get_fuse_conn(child_inode);
971	struct inode *inode;
972	struct dentry *parent;
973	struct fuse_entry_out outarg;
974	int err;
975
976	if (!fc->export_support)
977		return ERR_PTR(-ESTALE);
978
979	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
980			       &dotdot_name, &outarg, &inode);
981	if (err) {
982		if (err == -ENOENT)
983			return ERR_PTR(-ESTALE);
984		return ERR_PTR(err);
985	}
986
987	parent = d_obtain_alias(inode);
988	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
989		fuse_invalidate_entry_cache(parent);
990
991	return parent;
992}
993
994static const struct export_operations fuse_export_operations = {
995	.fh_to_dentry	= fuse_fh_to_dentry,
996	.fh_to_parent	= fuse_fh_to_parent,
997	.encode_fh	= fuse_encode_fh,
998	.get_parent	= fuse_get_parent,
999};
1000
1001static const struct super_operations fuse_super_operations = {
1002	.alloc_inode    = fuse_alloc_inode,
1003	.free_inode     = fuse_free_inode,
1004	.evict_inode	= fuse_evict_inode,
1005	.write_inode	= fuse_write_inode,
1006	.drop_inode	= generic_delete_inode,
1007	.put_super	= fuse_put_super,
1008	.umount_begin	= fuse_umount_begin,
1009	.statfs		= fuse_statfs,
1010	.sync_fs	= fuse_sync_fs,
1011	.show_options	= fuse_show_options,
1012};
1013
1014static void sanitize_global_limit(unsigned *limit)
1015{
1016	/*
1017	 * The default maximum number of async requests is calculated to consume
1018	 * 1/2^13 of the total memory, assuming 392 bytes per request.
1019	 */
1020	if (*limit == 0)
1021		*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1022
1023	if (*limit >= 1 << 16)
1024		*limit = (1 << 16) - 1;
1025}
1026
1027static int set_global_limit(const char *val, const struct kernel_param *kp)
1028{
1029	int rv;
1030
1031	rv = param_set_uint(val, kp);
1032	if (rv)
1033		return rv;
1034
1035	sanitize_global_limit((unsigned *)kp->arg);
1036
1037	return 0;
1038}
1039
1040static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1041{
1042	int cap_sys_admin = capable(CAP_SYS_ADMIN);
1043
1044	if (arg->minor < 13)
1045		return;
1046
1047	sanitize_global_limit(&max_user_bgreq);
1048	sanitize_global_limit(&max_user_congthresh);
1049
1050	spin_lock(&fc->bg_lock);
1051	if (arg->max_background) {
1052		fc->max_background = arg->max_background;
1053
1054		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1055			fc->max_background = max_user_bgreq;
1056	}
1057	if (arg->congestion_threshold) {
1058		fc->congestion_threshold = arg->congestion_threshold;
1059
1060		if (!cap_sys_admin &&
1061		    fc->congestion_threshold > max_user_congthresh)
1062			fc->congestion_threshold = max_user_congthresh;
1063	}
1064	spin_unlock(&fc->bg_lock);
1065}
1066
1067struct fuse_init_args {
1068	struct fuse_args args;
1069	struct fuse_init_in in;
1070	struct fuse_init_out out;
1071};
1072
1073static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1074			       int error)
1075{
1076	struct fuse_conn *fc = fm->fc;
1077	struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1078	struct fuse_init_out *arg = &ia->out;
1079	bool ok = true;
1080
1081	if (error || arg->major != FUSE_KERNEL_VERSION)
1082		ok = false;
1083	else {
1084		unsigned long ra_pages;
1085
1086		process_init_limits(fc, arg);
1087
1088		if (arg->minor >= 6) {
1089			ra_pages = arg->max_readahead / PAGE_SIZE;
1090			if (arg->flags & FUSE_ASYNC_READ)
1091				fc->async_read = 1;
1092			if (!(arg->flags & FUSE_POSIX_LOCKS))
1093				fc->no_lock = 1;
1094			if (arg->minor >= 17) {
1095				if (!(arg->flags & FUSE_FLOCK_LOCKS))
1096					fc->no_flock = 1;
1097			} else {
1098				if (!(arg->flags & FUSE_POSIX_LOCKS))
1099					fc->no_flock = 1;
1100			}
1101			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
1102				fc->atomic_o_trunc = 1;
1103			if (arg->minor >= 9) {
1104				/* LOOKUP has dependency on proto version */
1105				if (arg->flags & FUSE_EXPORT_SUPPORT)
1106					fc->export_support = 1;
1107			}
1108			if (arg->flags & FUSE_BIG_WRITES)
1109				fc->big_writes = 1;
1110			if (arg->flags & FUSE_DONT_MASK)
1111				fc->dont_mask = 1;
1112			if (arg->flags & FUSE_AUTO_INVAL_DATA)
1113				fc->auto_inval_data = 1;
1114			else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
1115				fc->explicit_inval_data = 1;
1116			if (arg->flags & FUSE_DO_READDIRPLUS) {
1117				fc->do_readdirplus = 1;
1118				if (arg->flags & FUSE_READDIRPLUS_AUTO)
1119					fc->readdirplus_auto = 1;
1120			}
1121			if (arg->flags & FUSE_ASYNC_DIO)
1122				fc->async_dio = 1;
1123			if (arg->flags & FUSE_WRITEBACK_CACHE)
1124				fc->writeback_cache = 1;
1125			if (arg->flags & FUSE_PARALLEL_DIROPS)
1126				fc->parallel_dirops = 1;
1127			if (arg->flags & FUSE_HANDLE_KILLPRIV)
1128				fc->handle_killpriv = 1;
1129			if (arg->time_gran && arg->time_gran <= 1000000000)
1130				fm->sb->s_time_gran = arg->time_gran;
1131			if ((arg->flags & FUSE_POSIX_ACL)) {
1132				fc->default_permissions = 1;
1133				fc->posix_acl = 1;
1134				fm->sb->s_xattr = fuse_acl_xattr_handlers;
1135			}
1136			if (arg->flags & FUSE_CACHE_SYMLINKS)
1137				fc->cache_symlinks = 1;
1138			if (arg->flags & FUSE_ABORT_ERROR)
1139				fc->abort_err = 1;
1140			if (arg->flags & FUSE_MAX_PAGES) {
1141				fc->max_pages =
1142					min_t(unsigned int, fc->max_pages_limit,
1143					max_t(unsigned int, arg->max_pages, 1));
1144			}
1145			if (IS_ENABLED(CONFIG_FUSE_DAX) &&
1146			    arg->flags & FUSE_MAP_ALIGNMENT &&
1147			    !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1148				ok = false;
1149			}
1150			if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
1151				fc->handle_killpriv_v2 = 1;
1152				fm->sb->s_flags |= SB_NOSEC;
1153			}
1154			if (arg->flags & FUSE_SETXATTR_EXT)
1155				fc->setxattr_ext = 1;
1156		} else {
1157			ra_pages = fc->max_read / PAGE_SIZE;
1158			fc->no_lock = 1;
1159			fc->no_flock = 1;
1160		}
1161
1162		fm->sb->s_bdi->ra_pages =
1163				min(fm->sb->s_bdi->ra_pages, ra_pages);
1164		fc->minor = arg->minor;
1165		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1166		fc->max_write = max_t(unsigned, 4096, fc->max_write);
1167		fc->conn_init = 1;
1168	}
1169	kfree(ia);
1170
1171	if (!ok) {
1172		fc->conn_init = 0;
1173		fc->conn_error = 1;
1174	}
1175
1176	fuse_set_initialized(fc);
1177	wake_up_all(&fc->blocked_waitq);
1178}
1179
1180void fuse_send_init(struct fuse_mount *fm)
1181{
1182	struct fuse_init_args *ia;
1183
1184	ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1185
1186	ia->in.major = FUSE_KERNEL_VERSION;
1187	ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1188	ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1189	ia->in.flags |=
1190		FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1191		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1192		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1193		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1194		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1195		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1196		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1197		FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1198		FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1199		FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT;
1200#ifdef CONFIG_FUSE_DAX
1201	if (fm->fc->dax)
1202		ia->in.flags |= FUSE_MAP_ALIGNMENT;
1203#endif
1204	if (fm->fc->auto_submounts)
1205		ia->in.flags |= FUSE_SUBMOUNTS;
1206
1207	ia->args.opcode = FUSE_INIT;
1208	ia->args.in_numargs = 1;
1209	ia->args.in_args[0].size = sizeof(ia->in);
1210	ia->args.in_args[0].value = &ia->in;
1211	ia->args.out_numargs = 1;
1212	/* Variable length argument used for backward compatibility
1213	   with interface version < 7.5.  Rest of init_out is zeroed
1214	   by do_get_request(), so a short reply is not a problem */
1215	ia->args.out_argvar = true;
1216	ia->args.out_args[0].size = sizeof(ia->out);
1217	ia->args.out_args[0].value = &ia->out;
1218	ia->args.force = true;
1219	ia->args.nocreds = true;
1220	ia->args.end = process_init_reply;
1221
1222	if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1223		process_init_reply(fm, &ia->args, -ENOTCONN);
1224}
1225EXPORT_SYMBOL_GPL(fuse_send_init);
1226
1227void fuse_free_conn(struct fuse_conn *fc)
1228{
1229	WARN_ON(!list_empty(&fc->devices));
1230	kfree_rcu(fc, rcu);
1231}
1232EXPORT_SYMBOL_GPL(fuse_free_conn);
1233
1234static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1235{
1236	int err;
1237	char *suffix = "";
1238
1239	if (sb->s_bdev) {
1240		suffix = "-fuseblk";
1241		/*
1242		 * sb->s_bdi points to blkdev's bdi however we want to redirect
1243		 * it to our private bdi...
1244		 */
1245		bdi_put(sb->s_bdi);
1246		sb->s_bdi = &noop_backing_dev_info;
1247	}
1248	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1249				   MINOR(fc->dev), suffix);
1250	if (err)
1251		return err;
1252
1253	/* fuse does it's own writeback accounting */
1254	sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1255	sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1256
1257	/*
1258	 * For a single fuse filesystem use max 1% of dirty +
1259	 * writeback threshold.
1260	 *
1261	 * This gives about 1M of write buffer for memory maps on a
1262	 * machine with 1G and 10% dirty_ratio, which should be more
1263	 * than enough.
1264	 *
1265	 * Privileged users can raise it by writing to
1266	 *
1267	 *    /sys/class/bdi/<bdi>/max_ratio
1268	 */
1269	bdi_set_max_ratio(sb->s_bdi, 1);
1270
1271	return 0;
1272}
1273
1274struct fuse_dev *fuse_dev_alloc(void)
1275{
1276	struct fuse_dev *fud;
1277	struct list_head *pq;
1278
1279	fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1280	if (!fud)
1281		return NULL;
1282
1283	pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1284	if (!pq) {
1285		kfree(fud);
1286		return NULL;
1287	}
1288
1289	fud->pq.processing = pq;
1290	fuse_pqueue_init(&fud->pq);
1291
1292	return fud;
1293}
1294EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1295
1296void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1297{
1298	fud->fc = fuse_conn_get(fc);
1299	spin_lock(&fc->lock);
1300	list_add_tail(&fud->entry, &fc->devices);
1301	spin_unlock(&fc->lock);
1302}
1303EXPORT_SYMBOL_GPL(fuse_dev_install);
1304
1305struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1306{
1307	struct fuse_dev *fud;
1308
1309	fud = fuse_dev_alloc();
1310	if (!fud)
1311		return NULL;
1312
1313	fuse_dev_install(fud, fc);
1314	return fud;
1315}
1316EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1317
1318void fuse_dev_free(struct fuse_dev *fud)
1319{
1320	struct fuse_conn *fc = fud->fc;
1321
1322	if (fc) {
1323		spin_lock(&fc->lock);
1324		list_del(&fud->entry);
1325		spin_unlock(&fc->lock);
1326
1327		fuse_conn_put(fc);
1328	}
1329	kfree(fud->pq.processing);
1330	kfree(fud);
1331}
1332EXPORT_SYMBOL_GPL(fuse_dev_free);
1333
1334static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1335				      const struct fuse_inode *fi)
1336{
1337	*attr = (struct fuse_attr){
1338		.ino		= fi->inode.i_ino,
1339		.size		= fi->inode.i_size,
1340		.blocks		= fi->inode.i_blocks,
1341		.atime		= fi->inode.i_atime.tv_sec,
1342		.mtime		= fi->inode.i_mtime.tv_sec,
1343		.ctime		= fi->inode.i_ctime.tv_sec,
1344		.atimensec	= fi->inode.i_atime.tv_nsec,
1345		.mtimensec	= fi->inode.i_mtime.tv_nsec,
1346		.ctimensec	= fi->inode.i_ctime.tv_nsec,
1347		.mode		= fi->inode.i_mode,
1348		.nlink		= fi->inode.i_nlink,
1349		.uid		= fi->inode.i_uid.val,
1350		.gid		= fi->inode.i_gid.val,
1351		.rdev		= fi->inode.i_rdev,
1352		.blksize	= 1u << fi->inode.i_blkbits,
1353	};
1354}
1355
1356static void fuse_sb_defaults(struct super_block *sb)
1357{
1358	sb->s_magic = FUSE_SUPER_MAGIC;
1359	sb->s_op = &fuse_super_operations;
1360	sb->s_xattr = fuse_xattr_handlers;
1361	sb->s_maxbytes = MAX_LFS_FILESIZE;
1362	sb->s_time_gran = 1;
1363	sb->s_export_op = &fuse_export_operations;
1364	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1365	if (sb->s_user_ns != &init_user_ns)
1366		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1367	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1368
1369	/*
1370	 * If we are not in the initial user namespace posix
1371	 * acls must be translated.
1372	 */
1373	if (sb->s_user_ns != &init_user_ns)
1374		sb->s_xattr = fuse_no_acl_xattr_handlers;
1375}
1376
1377static int fuse_fill_super_submount(struct super_block *sb,
1378				    struct fuse_inode *parent_fi)
1379{
1380	struct fuse_mount *fm = get_fuse_mount_super(sb);
1381	struct super_block *parent_sb = parent_fi->inode.i_sb;
1382	struct fuse_attr root_attr;
1383	struct inode *root;
1384
1385	fuse_sb_defaults(sb);
1386	fm->sb = sb;
1387
1388	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1389	sb->s_bdi = bdi_get(parent_sb->s_bdi);
1390
1391	sb->s_xattr = parent_sb->s_xattr;
1392	sb->s_time_gran = parent_sb->s_time_gran;
1393	sb->s_blocksize = parent_sb->s_blocksize;
1394	sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1395	sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1396	if (parent_sb->s_subtype && !sb->s_subtype)
1397		return -ENOMEM;
1398
1399	fuse_fill_attr_from_inode(&root_attr, parent_fi);
1400	root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1401	/*
1402	 * This inode is just a duplicate, so it is not looked up and
1403	 * its nlookup should not be incremented.  fuse_iget() does
1404	 * that, though, so undo it here.
1405	 */
1406	get_fuse_inode(root)->nlookup--;
1407	sb->s_d_op = &fuse_dentry_operations;
1408	sb->s_root = d_make_root(root);
1409	if (!sb->s_root)
1410		return -ENOMEM;
1411
1412	return 0;
1413}
1414
1415/* Filesystem context private data holds the FUSE inode of the mount point */
1416static int fuse_get_tree_submount(struct fs_context *fsc)
1417{
1418	struct fuse_mount *fm;
1419	struct fuse_inode *mp_fi = fsc->fs_private;
1420	struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1421	struct super_block *sb;
1422	int err;
1423
1424	fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1425	if (!fm)
1426		return -ENOMEM;
1427
1428	fsc->s_fs_info = fm;
1429	sb = sget_fc(fsc, NULL, set_anon_super_fc);
1430	if (IS_ERR(sb)) {
1431		kfree(fm);
1432		return PTR_ERR(sb);
1433	}
1434	fm->fc = fuse_conn_get(fc);
1435
1436	/* Initialize superblock, making @mp_fi its root */
1437	err = fuse_fill_super_submount(sb, mp_fi);
1438	if (err) {
1439		fuse_conn_put(fc);
1440		kfree(fm);
1441		sb->s_fs_info = NULL;
1442		deactivate_locked_super(sb);
1443		return err;
1444	}
1445
1446	down_write(&fc->killsb);
1447	list_add_tail(&fm->fc_entry, &fc->mounts);
1448	up_write(&fc->killsb);
1449
1450	sb->s_flags |= SB_ACTIVE;
1451	fsc->root = dget(sb->s_root);
1452
1453	return 0;
1454}
1455
1456static const struct fs_context_operations fuse_context_submount_ops = {
1457	.get_tree	= fuse_get_tree_submount,
1458};
1459
1460int fuse_init_fs_context_submount(struct fs_context *fsc)
1461{
1462	fsc->ops = &fuse_context_submount_ops;
1463	return 0;
1464}
1465EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1466
1467int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1468{
1469	struct fuse_dev *fud = NULL;
1470	struct fuse_mount *fm = get_fuse_mount_super(sb);
1471	struct fuse_conn *fc = fm->fc;
1472	struct inode *root;
1473	struct dentry *root_dentry;
1474	int err;
1475
1476	err = -EINVAL;
1477	if (sb->s_flags & SB_MANDLOCK)
1478		goto err;
1479
1480	rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1481	fuse_sb_defaults(sb);
1482
1483	if (ctx->is_bdev) {
1484#ifdef CONFIG_BLOCK
1485		err = -EINVAL;
1486		if (!sb_set_blocksize(sb, ctx->blksize))
1487			goto err;
1488#endif
1489	} else {
1490		sb->s_blocksize = PAGE_SIZE;
1491		sb->s_blocksize_bits = PAGE_SHIFT;
1492	}
1493
1494	sb->s_subtype = ctx->subtype;
1495	ctx->subtype = NULL;
1496	if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1497		err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
1498		if (err)
1499			goto err;
1500	}
1501
1502	if (ctx->fudptr) {
1503		err = -ENOMEM;
1504		fud = fuse_dev_alloc_install(fc);
1505		if (!fud)
1506			goto err_free_dax;
1507	}
1508
1509	fc->dev = sb->s_dev;
1510	fm->sb = sb;
1511	err = fuse_bdi_init(fc, sb);
1512	if (err)
1513		goto err_dev_free;
1514
1515	/* Handle umasking inside the fuse code */
1516	if (sb->s_flags & SB_POSIXACL)
1517		fc->dont_mask = 1;
1518	sb->s_flags |= SB_POSIXACL;
1519
1520	fc->default_permissions = ctx->default_permissions;
1521	fc->allow_other = ctx->allow_other;
1522	fc->user_id = ctx->user_id;
1523	fc->group_id = ctx->group_id;
1524	fc->legacy_opts_show = ctx->legacy_opts_show;
1525	fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1526	fc->destroy = ctx->destroy;
1527	fc->no_control = ctx->no_control;
1528	fc->no_force_umount = ctx->no_force_umount;
1529
1530	err = -ENOMEM;
1531	root = fuse_get_root_inode(sb, ctx->rootmode);
1532	sb->s_d_op = &fuse_root_dentry_operations;
1533	root_dentry = d_make_root(root);
1534	if (!root_dentry)
1535		goto err_dev_free;
1536	/* Root dentry doesn't have .d_revalidate */
1537	sb->s_d_op = &fuse_dentry_operations;
1538
1539	mutex_lock(&fuse_mutex);
1540	err = -EINVAL;
1541	if (ctx->fudptr && *ctx->fudptr)
1542		goto err_unlock;
1543
1544	err = fuse_ctl_add_conn(fc);
1545	if (err)
1546		goto err_unlock;
1547
1548	list_add_tail(&fc->entry, &fuse_conn_list);
1549	sb->s_root = root_dentry;
1550	if (ctx->fudptr)
1551		*ctx->fudptr = fud;
1552	mutex_unlock(&fuse_mutex);
1553	return 0;
1554
1555 err_unlock:
1556	mutex_unlock(&fuse_mutex);
1557	dput(root_dentry);
1558 err_dev_free:
1559	if (fud)
1560		fuse_dev_free(fud);
1561 err_free_dax:
1562	if (IS_ENABLED(CONFIG_FUSE_DAX))
1563		fuse_dax_conn_free(fc);
1564 err:
1565	return err;
1566}
1567EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1568
1569static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1570{
1571	struct fuse_fs_context *ctx = fsc->fs_private;
1572	int err;
1573	struct fuse_conn *fc;
1574	struct fuse_mount *fm;
1575
1576	if (!ctx->file || !ctx->rootmode_present ||
1577	    !ctx->user_id_present || !ctx->group_id_present)
1578		return -EINVAL;
1579
1580	/*
1581	 * Require mount to happen from the same user namespace which
1582	 * opened /dev/fuse to prevent potential attacks.
1583	 */
1584	err = -EINVAL;
1585	if ((ctx->file->f_op != &fuse_dev_operations) ||
1586	    (ctx->file->f_cred->user_ns != sb->s_user_ns))
1587		goto err;
1588	ctx->fudptr = &ctx->file->private_data;
1589
1590	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1591	err = -ENOMEM;
1592	if (!fc)
1593		goto err;
1594
1595	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1596	if (!fm) {
1597		kfree(fc);
1598		goto err;
1599	}
1600
1601	fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
1602	fc->release = fuse_free_conn;
1603
1604	sb->s_fs_info = fm;
1605
1606	err = fuse_fill_super_common(sb, ctx);
1607	if (err)
1608		goto err_put_conn;
1609	/* file->private_data shall be visible on all CPUs after this */
1610	smp_mb();
1611	fuse_send_init(get_fuse_mount_super(sb));
1612	return 0;
1613
1614 err_put_conn:
1615	fuse_conn_put(fc);
1616	kfree(fm);
1617	sb->s_fs_info = NULL;
1618 err:
1619	return err;
1620}
1621
1622/*
1623 * This is the path where user supplied an already initialized fuse dev.  In
1624 * this case never create a new super if the old one is gone.
1625 */
1626static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1627{
1628	return -ENOTCONN;
1629}
1630
1631static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1632{
1633
1634	return fsc->sget_key == get_fuse_conn_super(sb);
1635}
1636
1637static int fuse_get_tree(struct fs_context *fsc)
1638{
1639	struct fuse_fs_context *ctx = fsc->fs_private;
1640	struct fuse_dev *fud;
1641	struct super_block *sb;
1642	int err;
1643
1644	if (ctx->fd_present)
1645		ctx->file = fget(ctx->fd);
1646
1647	if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1648		err = get_tree_bdev(fsc, fuse_fill_super);
1649		goto out_fput;
1650	}
1651	/*
1652	 * While block dev mount can be initialized with a dummy device fd
1653	 * (found by device name), normal fuse mounts can't
1654	 */
1655	if (!ctx->file)
1656		return -EINVAL;
1657
1658	/*
1659	 * Allow creating a fuse mount with an already initialized fuse
1660	 * connection
1661	 */
1662	fud = READ_ONCE(ctx->file->private_data);
1663	if (ctx->file->f_op == &fuse_dev_operations && fud) {
1664		fsc->sget_key = fud->fc;
1665		sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1666		err = PTR_ERR_OR_ZERO(sb);
1667		if (!IS_ERR(sb))
1668			fsc->root = dget(sb->s_root);
1669	} else {
1670		err = get_tree_nodev(fsc, fuse_fill_super);
1671	}
1672out_fput:
1673	if (ctx->file)
1674		fput(ctx->file);
1675	return err;
1676}
1677
1678static const struct fs_context_operations fuse_context_ops = {
1679	.free		= fuse_free_fsc,
1680	.parse_param	= fuse_parse_param,
1681	.reconfigure	= fuse_reconfigure,
1682	.get_tree	= fuse_get_tree,
1683};
1684
1685/*
1686 * Set up the filesystem mount context.
1687 */
1688static int fuse_init_fs_context(struct fs_context *fsc)
1689{
1690	struct fuse_fs_context *ctx;
1691
1692	ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1693	if (!ctx)
1694		return -ENOMEM;
1695
1696	ctx->max_read = ~0;
1697	ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1698	ctx->legacy_opts_show = true;
1699
1700#ifdef CONFIG_BLOCK
1701	if (fsc->fs_type == &fuseblk_fs_type) {
1702		ctx->is_bdev = true;
1703		ctx->destroy = true;
1704	}
1705#endif
1706
1707	fsc->fs_private = ctx;
1708	fsc->ops = &fuse_context_ops;
1709	return 0;
1710}
1711
1712bool fuse_mount_remove(struct fuse_mount *fm)
1713{
1714	struct fuse_conn *fc = fm->fc;
1715	bool last = false;
1716
1717	down_write(&fc->killsb);
1718	list_del_init(&fm->fc_entry);
1719	if (list_empty(&fc->mounts))
1720		last = true;
1721	up_write(&fc->killsb);
1722
1723	return last;
1724}
1725EXPORT_SYMBOL_GPL(fuse_mount_remove);
1726
1727void fuse_conn_destroy(struct fuse_mount *fm)
1728{
1729	struct fuse_conn *fc = fm->fc;
1730
1731	if (fc->destroy)
1732		fuse_send_destroy(fm);
1733
1734	fuse_abort_conn(fc);
1735	fuse_wait_aborted(fc);
1736
1737	if (!list_empty(&fc->entry)) {
1738		mutex_lock(&fuse_mutex);
1739		list_del(&fc->entry);
1740		fuse_ctl_remove_conn(fc);
1741		mutex_unlock(&fuse_mutex);
1742	}
1743}
1744EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1745
1746static void fuse_sb_destroy(struct super_block *sb)
1747{
1748	struct fuse_mount *fm = get_fuse_mount_super(sb);
1749	bool last;
1750
1751	if (fm) {
1752		last = fuse_mount_remove(fm);
1753		if (last)
1754			fuse_conn_destroy(fm);
1755	}
1756}
1757
1758static void fuse_kill_sb_anon(struct super_block *sb)
1759{
1760	fuse_sb_destroy(sb);
1761	kill_anon_super(sb);
1762}
1763
1764static struct file_system_type fuse_fs_type = {
1765	.owner		= THIS_MODULE,
1766	.name		= "fuse",
1767	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1768	.init_fs_context = fuse_init_fs_context,
1769	.parameters	= fuse_fs_parameters,
1770	.kill_sb	= fuse_kill_sb_anon,
1771};
1772MODULE_ALIAS_FS("fuse");
1773
1774#ifdef CONFIG_BLOCK
1775static void fuse_kill_sb_blk(struct super_block *sb)
1776{
1777	fuse_sb_destroy(sb);
1778	kill_block_super(sb);
1779}
1780
1781static struct file_system_type fuseblk_fs_type = {
1782	.owner		= THIS_MODULE,
1783	.name		= "fuseblk",
1784	.init_fs_context = fuse_init_fs_context,
1785	.parameters	= fuse_fs_parameters,
1786	.kill_sb	= fuse_kill_sb_blk,
1787	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1788};
1789MODULE_ALIAS_FS("fuseblk");
1790
1791static inline int register_fuseblk(void)
1792{
1793	return register_filesystem(&fuseblk_fs_type);
1794}
1795
1796static inline void unregister_fuseblk(void)
1797{
1798	unregister_filesystem(&fuseblk_fs_type);
1799}
1800#else
1801static inline int register_fuseblk(void)
1802{
1803	return 0;
1804}
1805
1806static inline void unregister_fuseblk(void)
1807{
1808}
1809#endif
1810
1811static void fuse_inode_init_once(void *foo)
1812{
1813	struct inode *inode = foo;
1814
1815	inode_init_once(inode);
1816}
1817
1818static int __init fuse_fs_init(void)
1819{
1820	int err;
1821
1822	fuse_inode_cachep = kmem_cache_create("fuse_inode",
1823			sizeof(struct fuse_inode), 0,
1824			SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1825			fuse_inode_init_once);
1826	err = -ENOMEM;
1827	if (!fuse_inode_cachep)
1828		goto out;
1829
1830	err = register_fuseblk();
1831	if (err)
1832		goto out2;
1833
1834	err = register_filesystem(&fuse_fs_type);
1835	if (err)
1836		goto out3;
1837
1838	return 0;
1839
1840 out3:
1841	unregister_fuseblk();
1842 out2:
1843	kmem_cache_destroy(fuse_inode_cachep);
1844 out:
1845	return err;
1846}
1847
1848static void fuse_fs_cleanup(void)
1849{
1850	unregister_filesystem(&fuse_fs_type);
1851	unregister_fuseblk();
1852
1853	/*
1854	 * Make sure all delayed rcu free inodes are flushed before we
1855	 * destroy cache.
1856	 */
1857	rcu_barrier();
1858	kmem_cache_destroy(fuse_inode_cachep);
1859}
1860
1861static struct kobject *fuse_kobj;
1862
1863static int fuse_sysfs_init(void)
1864{
1865	int err;
1866
1867	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1868	if (!fuse_kobj) {
1869		err = -ENOMEM;
1870		goto out_err;
1871	}
1872
1873	err = sysfs_create_mount_point(fuse_kobj, "connections");
1874	if (err)
1875		goto out_fuse_unregister;
1876
1877	return 0;
1878
1879 out_fuse_unregister:
1880	kobject_put(fuse_kobj);
1881 out_err:
1882	return err;
1883}
1884
1885static void fuse_sysfs_cleanup(void)
1886{
1887	sysfs_remove_mount_point(fuse_kobj, "connections");
1888	kobject_put(fuse_kobj);
1889}
1890
1891static int __init fuse_init(void)
1892{
1893	int res;
1894
1895	pr_info("init (API version %i.%i)\n",
1896		FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1897
1898	INIT_LIST_HEAD(&fuse_conn_list);
1899	res = fuse_fs_init();
1900	if (res)
1901		goto err;
1902
1903	res = fuse_dev_init();
1904	if (res)
1905		goto err_fs_cleanup;
1906
1907	res = fuse_sysfs_init();
1908	if (res)
1909		goto err_dev_cleanup;
1910
1911	res = fuse_ctl_init();
1912	if (res)
1913		goto err_sysfs_cleanup;
1914
1915	sanitize_global_limit(&max_user_bgreq);
1916	sanitize_global_limit(&max_user_congthresh);
1917
1918	return 0;
1919
1920 err_sysfs_cleanup:
1921	fuse_sysfs_cleanup();
1922 err_dev_cleanup:
1923	fuse_dev_cleanup();
1924 err_fs_cleanup:
1925	fuse_fs_cleanup();
1926 err:
1927	return res;
1928}
1929
1930static void __exit fuse_exit(void)
1931{
1932	pr_debug("exit\n");
1933
1934	fuse_ctl_cleanup();
1935	fuse_sysfs_cleanup();
1936	fuse_fs_cleanup();
1937	fuse_dev_cleanup();
1938}
1939
1940module_init(fuse_init);
1941module_exit(fuse_exit);
1942