2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
5 This program can be distributed under the terms of the GNU GPL.
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>
28 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
29 MODULE_DESCRIPTION("Filesystem in Userspace");
30 MODULE_LICENSE("GPL");
32 static struct kmem_cache *fuse_inode_cachep;
33 struct list_head fuse_conn_list;
34 DEFINE_MUTEX(fuse_mutex);
36 static int set_global_limit(const char *val, const struct kernel_param *kp);
38 unsigned max_user_bgreq;
39 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
40 &max_user_bgreq, 0644);
41 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
42 MODULE_PARM_DESC(max_user_bgreq,
43 "Global limit for the maximum number of backgrounded requests an "
44 "unprivileged user can set");
46 unsigned max_user_congthresh;
47 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
48 &max_user_congthresh, 0644);
49 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
50 MODULE_PARM_DESC(max_user_congthresh,
51 "Global limit for the maximum congestion threshold an "
52 "unprivileged user can set");
54 #define FUSE_DEFAULT_BLKSIZE 512
56 /** Maximum number of outstanding background requests */
57 #define FUSE_DEFAULT_MAX_BACKGROUND 12
59 /** Congestion starts at 75% of maximum */
60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
63 static struct file_system_type fuseblk_fs_type;
66 struct fuse_forget_link *fuse_alloc_forget(void)
68 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
71 static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void)
73 struct fuse_submount_lookup *sl;
75 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT);
78 sl->forget = fuse_alloc_forget();
89 static struct inode *fuse_alloc_inode(struct super_block *sb)
91 struct fuse_inode *fi;
93 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
101 fi->attr_version = 0;
104 fi->submount_lookup = NULL;
105 mutex_init(&fi->mutex);
106 spin_lock_init(&fi->lock);
107 fi->forget = fuse_alloc_forget();
111 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
112 goto out_free_forget;
119 kmem_cache_free(fuse_inode_cachep, fi);
123 static void fuse_free_inode(struct inode *inode)
125 struct fuse_inode *fi = get_fuse_inode(inode);
127 mutex_destroy(&fi->mutex);
129 #ifdef CONFIG_FUSE_DAX
132 kmem_cache_free(fuse_inode_cachep, fi);
135 static void fuse_cleanup_submount_lookup(struct fuse_conn *fc,
136 struct fuse_submount_lookup *sl)
138 if (!refcount_dec_and_test(&sl->count))
141 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1);
146 static void fuse_evict_inode(struct inode *inode)
148 struct fuse_inode *fi = get_fuse_inode(inode);
150 /* Will write inode on close/munmap and in all other dirtiers */
151 WARN_ON(inode->i_state & I_DIRTY_INODE);
153 truncate_inode_pages_final(&inode->i_data);
155 if (inode->i_sb->s_flags & SB_ACTIVE) {
156 struct fuse_conn *fc = get_fuse_conn(inode);
158 if (FUSE_IS_DAX(inode))
159 fuse_dax_inode_cleanup(inode);
161 fuse_queue_forget(fc, fi->forget, fi->nodeid,
166 if (fi->submount_lookup) {
167 fuse_cleanup_submount_lookup(fc, fi->submount_lookup);
168 fi->submount_lookup = NULL;
171 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
172 WARN_ON(!list_empty(&fi->write_files));
173 WARN_ON(!list_empty(&fi->queued_writes));
177 static int fuse_reconfigure(struct fs_context *fsc)
179 struct super_block *sb = fsc->root->d_sb;
182 if (fsc->sb_flags & SB_MANDLOCK)
189 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
190 * so that it will fit.
192 static ino_t fuse_squash_ino(u64 ino64)
194 ino_t ino = (ino_t) ino64;
195 if (sizeof(ino_t) < sizeof(u64))
196 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
200 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
201 struct fuse_statx *sx,
202 u64 attr_valid, u32 cache_mask)
204 struct fuse_conn *fc = get_fuse_conn(inode);
205 struct fuse_inode *fi = get_fuse_inode(inode);
207 lockdep_assert_held(&fi->lock);
209 fi->attr_version = atomic64_inc_return(&fc->attr_version);
210 fi->i_time = attr_valid;
211 /* Clear basic stats from invalid mask */
212 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0);
214 inode->i_ino = fuse_squash_ino(attr->ino);
215 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
216 set_nlink(inode, attr->nlink);
217 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
218 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
219 inode->i_blocks = attr->blocks;
222 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
223 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
224 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
226 inode->i_atime.tv_sec = attr->atime;
227 inode->i_atime.tv_nsec = attr->atimensec;
228 /* mtime from server may be stale due to local buffered write */
229 if (!(cache_mask & STATX_MTIME)) {
230 inode->i_mtime.tv_sec = attr->mtime;
231 inode->i_mtime.tv_nsec = attr->mtimensec;
233 if (!(cache_mask & STATX_CTIME)) {
234 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
239 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
242 * Btime has been queried, cache is valid (whether or not btime
243 * is available or not) so clear STATX_BTIME from inval_mask.
245 * Availability of the btime attribute is indicated in
248 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0);
249 if (sx->mask & STATX_BTIME) {
250 set_bit(FUSE_I_BTIME, &fi->state);
251 fi->i_btime.tv_sec = sx->btime.tv_sec;
252 fi->i_btime.tv_nsec = sx->btime.tv_nsec;
256 if (attr->blksize != 0)
257 inode->i_blkbits = ilog2(attr->blksize);
259 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
262 * Don't set the sticky bit in i_mode, unless we want the VFS
263 * to check permissions. This prevents failures due to the
264 * check in may_delete().
266 fi->orig_i_mode = inode->i_mode;
267 if (!fc->default_permissions)
268 inode->i_mode &= ~S_ISVTX;
270 fi->orig_ino = attr->ino;
273 * We are refreshing inode data and it is possible that another
274 * client set suid/sgid or security.capability xattr. So clear
275 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
276 * was set or if security.capability xattr was set. But we don't
277 * know if security.capability has been set or not. So clear it
278 * anyway. Its less efficient but should be safe.
280 inode->i_flags &= ~S_NOSEC;
283 u32 fuse_get_cache_mask(struct inode *inode)
285 struct fuse_conn *fc = get_fuse_conn(inode);
287 if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
290 return STATX_MTIME | STATX_CTIME | STATX_SIZE;
293 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
294 struct fuse_statx *sx,
295 u64 attr_valid, u64 attr_version)
297 struct fuse_conn *fc = get_fuse_conn(inode);
298 struct fuse_inode *fi = get_fuse_inode(inode);
301 struct timespec64 old_mtime;
303 spin_lock(&fi->lock);
305 * In case of writeback_cache enabled, writes update mtime, ctime and
306 * may update i_size. In these cases trust the cached value in the
309 cache_mask = fuse_get_cache_mask(inode);
310 if (cache_mask & STATX_SIZE)
311 attr->size = i_size_read(inode);
313 if (cache_mask & STATX_MTIME) {
314 attr->mtime = inode->i_mtime.tv_sec;
315 attr->mtimensec = inode->i_mtime.tv_nsec;
317 if (cache_mask & STATX_CTIME) {
318 attr->ctime = inode_get_ctime(inode).tv_sec;
319 attr->ctimensec = inode_get_ctime(inode).tv_nsec;
322 if ((attr_version != 0 && fi->attr_version > attr_version) ||
323 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
324 spin_unlock(&fi->lock);
328 old_mtime = inode->i_mtime;
329 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask);
331 oldsize = inode->i_size;
333 * In case of writeback_cache enabled, the cached writes beyond EOF
334 * extend local i_size without keeping userspace server in sync. So,
335 * attr->size coming from server can be stale. We cannot trust it.
337 if (!(cache_mask & STATX_SIZE))
338 i_size_write(inode, attr->size);
339 spin_unlock(&fi->lock);
341 if (!cache_mask && S_ISREG(inode->i_mode)) {
344 if (oldsize != attr->size) {
345 truncate_pagecache(inode, attr->size);
346 if (!fc->explicit_inval_data)
348 } else if (fc->auto_inval_data) {
349 struct timespec64 new_mtime = {
350 .tv_sec = attr->mtime,
351 .tv_nsec = attr->mtimensec,
355 * Auto inval mode also checks and invalidates if mtime
358 if (!timespec64_equal(&old_mtime, &new_mtime))
363 invalidate_inode_pages2(inode->i_mapping);
366 if (IS_ENABLED(CONFIG_FUSE_DAX))
367 fuse_dax_dontcache(inode, attr->flags);
370 static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl,
374 refcount_set(&sl->count, 1);
377 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr,
378 struct fuse_conn *fc)
380 inode->i_mode = attr->mode & S_IFMT;
381 inode->i_size = attr->size;
382 inode->i_mtime.tv_sec = attr->mtime;
383 inode->i_mtime.tv_nsec = attr->mtimensec;
384 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
385 if (S_ISREG(inode->i_mode)) {
386 fuse_init_common(inode);
387 fuse_init_file_inode(inode, attr->flags);
388 } else if (S_ISDIR(inode->i_mode))
389 fuse_init_dir(inode);
390 else if (S_ISLNK(inode->i_mode))
391 fuse_init_symlink(inode);
392 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
393 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
394 fuse_init_common(inode);
395 init_special_inode(inode, inode->i_mode,
396 new_decode_dev(attr->rdev));
400 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL
401 * so they see the exact same behavior as before.
404 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
407 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
409 u64 nodeid = *(u64 *) _nodeidp;
410 if (get_node_id(inode) == nodeid)
416 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
418 u64 nodeid = *(u64 *) _nodeidp;
419 get_fuse_inode(inode)->nodeid = nodeid;
423 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
424 int generation, struct fuse_attr *attr,
425 u64 attr_valid, u64 attr_version)
428 struct fuse_inode *fi;
429 struct fuse_conn *fc = get_fuse_conn_super(sb);
432 * Auto mount points get their node id from the submount root, which is
433 * not a unique identifier within this filesystem.
435 * To avoid conflicts, do not place submount points into the inode hash
438 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
439 S_ISDIR(attr->mode)) {
440 struct fuse_inode *fi;
442 inode = new_inode(sb);
446 fuse_init_inode(inode, attr, fc);
447 fi = get_fuse_inode(inode);
449 fi->submount_lookup = fuse_alloc_submount_lookup();
450 if (!fi->submount_lookup) {
454 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */
455 fuse_init_submount_lookup(fi->submount_lookup, nodeid);
456 inode->i_flags |= S_AUTOMOUNT;
461 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
465 if ((inode->i_state & I_NEW)) {
466 inode->i_flags |= S_NOATIME;
467 if (!fc->writeback_cache || !S_ISREG(attr->mode))
468 inode->i_flags |= S_NOCMTIME;
469 inode->i_generation = generation;
470 fuse_init_inode(inode, attr, fc);
471 unlock_new_inode(inode);
472 } else if (fuse_stale_inode(inode, generation, attr)) {
473 /* nodeid was reused, any I/O on the old inode should fail */
474 fuse_make_bad(inode);
478 fi = get_fuse_inode(inode);
479 spin_lock(&fi->lock);
481 spin_unlock(&fi->lock);
483 fuse_change_attributes(inode, attr, NULL, attr_valid, attr_version);
488 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
489 struct fuse_mount **fm)
491 struct fuse_mount *fm_iter;
494 WARN_ON(!rwsem_is_locked(&fc->killsb));
495 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
499 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
510 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
511 loff_t offset, loff_t len)
513 struct fuse_inode *fi;
518 inode = fuse_ilookup(fc, nodeid, NULL);
522 fi = get_fuse_inode(inode);
523 spin_lock(&fi->lock);
524 fi->attr_version = atomic64_inc_return(&fc->attr_version);
525 spin_unlock(&fi->lock);
527 fuse_invalidate_attr(inode);
528 forget_all_cached_acls(inode);
530 pg_start = offset >> PAGE_SHIFT;
534 pg_end = (offset + len - 1) >> PAGE_SHIFT;
535 invalidate_inode_pages2_range(inode->i_mapping,
542 bool fuse_lock_inode(struct inode *inode)
546 if (!get_fuse_conn(inode)->parallel_dirops) {
547 mutex_lock(&get_fuse_inode(inode)->mutex);
554 void fuse_unlock_inode(struct inode *inode, bool locked)
557 mutex_unlock(&get_fuse_inode(inode)->mutex);
560 static void fuse_umount_begin(struct super_block *sb)
562 struct fuse_conn *fc = get_fuse_conn_super(sb);
564 if (fc->no_force_umount)
569 // Only retire block-device-based superblocks.
570 if (sb->s_bdev != NULL)
574 static void fuse_send_destroy(struct fuse_mount *fm)
576 if (fm->fc->conn_init) {
579 args.opcode = FUSE_DESTROY;
582 fuse_simple_request(fm, &args);
586 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
588 stbuf->f_type = FUSE_SUPER_MAGIC;
589 stbuf->f_bsize = attr->bsize;
590 stbuf->f_frsize = attr->frsize;
591 stbuf->f_blocks = attr->blocks;
592 stbuf->f_bfree = attr->bfree;
593 stbuf->f_bavail = attr->bavail;
594 stbuf->f_files = attr->files;
595 stbuf->f_ffree = attr->ffree;
596 stbuf->f_namelen = attr->namelen;
597 /* fsid is left zero */
600 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
602 struct super_block *sb = dentry->d_sb;
603 struct fuse_mount *fm = get_fuse_mount_super(sb);
605 struct fuse_statfs_out outarg;
608 if (!fuse_allow_current_process(fm->fc)) {
609 buf->f_type = FUSE_SUPER_MAGIC;
613 memset(&outarg, 0, sizeof(outarg));
615 args.opcode = FUSE_STATFS;
616 args.nodeid = get_node_id(d_inode(dentry));
617 args.out_numargs = 1;
618 args.out_args[0].size = sizeof(outarg);
619 args.out_args[0].value = &outarg;
620 err = fuse_simple_request(fm, &args);
622 convert_fuse_statfs(buf, &outarg.st);
626 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
628 struct fuse_sync_bucket *bucket;
630 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
632 init_waitqueue_head(&bucket->waitq);
633 /* Initial active count */
634 atomic_set(&bucket->count, 1);
639 static void fuse_sync_fs_writes(struct fuse_conn *fc)
641 struct fuse_sync_bucket *bucket, *new_bucket;
644 new_bucket = fuse_sync_bucket_alloc();
645 spin_lock(&fc->lock);
646 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
647 count = atomic_read(&bucket->count);
649 /* No outstanding writes? */
651 spin_unlock(&fc->lock);
657 * Completion of new bucket depends on completion of this bucket, so add
660 atomic_inc(&new_bucket->count);
661 rcu_assign_pointer(fc->curr_bucket, new_bucket);
662 spin_unlock(&fc->lock);
664 * Drop initial active count. At this point if all writes in this and
665 * ancestor buckets complete, the count will go to zero and this task
668 atomic_dec(&bucket->count);
670 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
672 /* Drop temp count on descendant bucket */
673 fuse_sync_bucket_dec(new_bucket);
674 kfree_rcu(bucket, rcu);
677 static int fuse_sync_fs(struct super_block *sb, int wait)
679 struct fuse_mount *fm = get_fuse_mount_super(sb);
680 struct fuse_conn *fc = fm->fc;
681 struct fuse_syncfs_in inarg;
686 * Userspace cannot handle the wait == 0 case. Avoid a
687 * gratuitous roundtrip.
692 /* The filesystem is being unmounted. Nothing to do. */
699 fuse_sync_fs_writes(fc);
701 memset(&inarg, 0, sizeof(inarg));
703 args.in_args[0].size = sizeof(inarg);
704 args.in_args[0].value = &inarg;
705 args.opcode = FUSE_SYNCFS;
706 args.nodeid = get_node_id(sb->s_root->d_inode);
707 args.out_numargs = 0;
709 err = fuse_simple_request(fm, &args);
710 if (err == -ENOSYS) {
725 OPT_DEFAULT_PERMISSIONS,
732 static const struct fs_parameter_spec fuse_fs_parameters[] = {
733 fsparam_string ("source", OPT_SOURCE),
734 fsparam_u32 ("fd", OPT_FD),
735 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
736 fsparam_u32 ("user_id", OPT_USER_ID),
737 fsparam_u32 ("group_id", OPT_GROUP_ID),
738 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
739 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
740 fsparam_u32 ("max_read", OPT_MAX_READ),
741 fsparam_u32 ("blksize", OPT_BLKSIZE),
742 fsparam_string ("subtype", OPT_SUBTYPE),
746 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
748 struct fs_parse_result result;
749 struct fuse_fs_context *ctx = fsc->fs_private;
752 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
754 * Ignore options coming from mount(MS_REMOUNT) for backward
760 return invalfc(fsc, "No changes allowed in reconfigure");
763 opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
770 return invalfc(fsc, "Multiple sources specified");
771 fsc->source = param->string;
772 param->string = NULL;
777 return invalfc(fsc, "Multiple subtypes specified");
778 ctx->subtype = param->string;
779 param->string = NULL;
783 ctx->fd = result.uint_32;
784 ctx->fd_present = true;
788 if (!fuse_valid_type(result.uint_32))
789 return invalfc(fsc, "Invalid rootmode");
790 ctx->rootmode = result.uint_32;
791 ctx->rootmode_present = true;
795 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
796 if (!uid_valid(ctx->user_id))
797 return invalfc(fsc, "Invalid user_id");
798 ctx->user_id_present = true;
802 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
803 if (!gid_valid(ctx->group_id))
804 return invalfc(fsc, "Invalid group_id");
805 ctx->group_id_present = true;
808 case OPT_DEFAULT_PERMISSIONS:
809 ctx->default_permissions = true;
812 case OPT_ALLOW_OTHER:
813 ctx->allow_other = true;
817 ctx->max_read = result.uint_32;
822 return invalfc(fsc, "blksize only supported for fuseblk");
823 ctx->blksize = result.uint_32;
833 static void fuse_free_fsc(struct fs_context *fsc)
835 struct fuse_fs_context *ctx = fsc->fs_private;
843 static int fuse_show_options(struct seq_file *m, struct dentry *root)
845 struct super_block *sb = root->d_sb;
846 struct fuse_conn *fc = get_fuse_conn_super(sb);
848 if (fc->legacy_opts_show) {
849 seq_printf(m, ",user_id=%u",
850 from_kuid_munged(fc->user_ns, fc->user_id));
851 seq_printf(m, ",group_id=%u",
852 from_kgid_munged(fc->user_ns, fc->group_id));
853 if (fc->default_permissions)
854 seq_puts(m, ",default_permissions");
856 seq_puts(m, ",allow_other");
857 if (fc->max_read != ~0)
858 seq_printf(m, ",max_read=%u", fc->max_read);
859 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
860 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
862 #ifdef CONFIG_FUSE_DAX
863 if (fc->dax_mode == FUSE_DAX_ALWAYS)
864 seq_puts(m, ",dax=always");
865 else if (fc->dax_mode == FUSE_DAX_NEVER)
866 seq_puts(m, ",dax=never");
867 else if (fc->dax_mode == FUSE_DAX_INODE_USER)
868 seq_puts(m, ",dax=inode");
874 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
875 const struct fuse_iqueue_ops *ops,
878 memset(fiq, 0, sizeof(struct fuse_iqueue));
879 spin_lock_init(&fiq->lock);
880 init_waitqueue_head(&fiq->waitq);
881 INIT_LIST_HEAD(&fiq->pending);
882 INIT_LIST_HEAD(&fiq->interrupts);
883 fiq->forget_list_tail = &fiq->forget_list_head;
889 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
893 spin_lock_init(&fpq->lock);
894 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
895 INIT_LIST_HEAD(&fpq->processing[i]);
896 INIT_LIST_HEAD(&fpq->io);
900 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
901 struct user_namespace *user_ns,
902 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
904 memset(fc, 0, sizeof(*fc));
905 spin_lock_init(&fc->lock);
906 spin_lock_init(&fc->bg_lock);
907 init_rwsem(&fc->killsb);
908 refcount_set(&fc->count, 1);
909 atomic_set(&fc->dev_count, 1);
910 init_waitqueue_head(&fc->blocked_waitq);
911 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
912 INIT_LIST_HEAD(&fc->bg_queue);
913 INIT_LIST_HEAD(&fc->entry);
914 INIT_LIST_HEAD(&fc->devices);
915 atomic_set(&fc->num_waiting, 0);
916 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
917 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
918 atomic64_set(&fc->khctr, 0);
919 fc->polled_files = RB_ROOT;
923 atomic64_set(&fc->attr_version, 1);
924 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
925 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
926 fc->user_ns = get_user_ns(user_ns);
927 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
928 fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
930 INIT_LIST_HEAD(&fc->mounts);
931 list_add(&fm->fc_entry, &fc->mounts);
934 EXPORT_SYMBOL_GPL(fuse_conn_init);
936 void fuse_conn_put(struct fuse_conn *fc)
938 if (refcount_dec_and_test(&fc->count)) {
939 struct fuse_iqueue *fiq = &fc->iq;
940 struct fuse_sync_bucket *bucket;
942 if (IS_ENABLED(CONFIG_FUSE_DAX))
943 fuse_dax_conn_free(fc);
944 if (fiq->ops->release)
945 fiq->ops->release(fiq);
946 put_pid_ns(fc->pid_ns);
947 put_user_ns(fc->user_ns);
948 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
950 WARN_ON(atomic_read(&bucket->count) != 1);
956 EXPORT_SYMBOL_GPL(fuse_conn_put);
958 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
960 refcount_inc(&fc->count);
963 EXPORT_SYMBOL_GPL(fuse_conn_get);
965 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
967 struct fuse_attr attr;
968 memset(&attr, 0, sizeof(attr));
971 attr.ino = FUSE_ROOT_ID;
973 return fuse_iget(sb, 1, 0, &attr, 0, 0);
976 struct fuse_inode_handle {
981 static struct dentry *fuse_get_dentry(struct super_block *sb,
982 struct fuse_inode_handle *handle)
984 struct fuse_conn *fc = get_fuse_conn_super(sb);
986 struct dentry *entry;
989 if (handle->nodeid == 0)
992 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
994 struct fuse_entry_out outarg;
995 const struct qstr name = QSTR_INIT(".", 1);
997 if (!fc->export_support)
1000 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
1002 if (err && err != -ENOENT)
1004 if (err || !inode) {
1009 if (get_node_id(inode) != handle->nodeid)
1013 if (inode->i_generation != handle->generation)
1016 entry = d_obtain_alias(inode);
1017 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
1018 fuse_invalidate_entry_cache(entry);
1025 return ERR_PTR(err);
1028 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
1029 struct inode *parent)
1031 int len = parent ? 6 : 3;
1035 if (*max_len < len) {
1037 return FILEID_INVALID;
1040 nodeid = get_fuse_inode(inode)->nodeid;
1041 generation = inode->i_generation;
1043 fh[0] = (u32)(nodeid >> 32);
1044 fh[1] = (u32)(nodeid & 0xffffffff);
1048 nodeid = get_fuse_inode(parent)->nodeid;
1049 generation = parent->i_generation;
1051 fh[3] = (u32)(nodeid >> 32);
1052 fh[4] = (u32)(nodeid & 0xffffffff);
1057 return parent ? 0x82 : 0x81;
1060 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
1061 struct fid *fid, int fh_len, int fh_type)
1063 struct fuse_inode_handle handle;
1065 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
1068 handle.nodeid = (u64) fid->raw[0] << 32;
1069 handle.nodeid |= (u64) fid->raw[1];
1070 handle.generation = fid->raw[2];
1071 return fuse_get_dentry(sb, &handle);
1074 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
1075 struct fid *fid, int fh_len, int fh_type)
1077 struct fuse_inode_handle parent;
1079 if (fh_type != 0x82 || fh_len < 6)
1082 parent.nodeid = (u64) fid->raw[3] << 32;
1083 parent.nodeid |= (u64) fid->raw[4];
1084 parent.generation = fid->raw[5];
1085 return fuse_get_dentry(sb, &parent);
1088 static struct dentry *fuse_get_parent(struct dentry *child)
1090 struct inode *child_inode = d_inode(child);
1091 struct fuse_conn *fc = get_fuse_conn(child_inode);
1092 struct inode *inode;
1093 struct dentry *parent;
1094 struct fuse_entry_out outarg;
1097 if (!fc->export_support)
1098 return ERR_PTR(-ESTALE);
1100 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1101 &dotdot_name, &outarg, &inode);
1104 return ERR_PTR(-ESTALE);
1105 return ERR_PTR(err);
1108 parent = d_obtain_alias(inode);
1109 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1110 fuse_invalidate_entry_cache(parent);
1115 static const struct export_operations fuse_export_operations = {
1116 .fh_to_dentry = fuse_fh_to_dentry,
1117 .fh_to_parent = fuse_fh_to_parent,
1118 .encode_fh = fuse_encode_fh,
1119 .get_parent = fuse_get_parent,
1122 static const struct super_operations fuse_super_operations = {
1123 .alloc_inode = fuse_alloc_inode,
1124 .free_inode = fuse_free_inode,
1125 .evict_inode = fuse_evict_inode,
1126 .write_inode = fuse_write_inode,
1127 .drop_inode = generic_delete_inode,
1128 .umount_begin = fuse_umount_begin,
1129 .statfs = fuse_statfs,
1130 .sync_fs = fuse_sync_fs,
1131 .show_options = fuse_show_options,
1134 static void sanitize_global_limit(unsigned *limit)
1137 * The default maximum number of async requests is calculated to consume
1138 * 1/2^13 of the total memory, assuming 392 bytes per request.
1141 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1143 if (*limit >= 1 << 16)
1144 *limit = (1 << 16) - 1;
1147 static int set_global_limit(const char *val, const struct kernel_param *kp)
1151 rv = param_set_uint(val, kp);
1155 sanitize_global_limit((unsigned *)kp->arg);
1160 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1162 int cap_sys_admin = capable(CAP_SYS_ADMIN);
1164 if (arg->minor < 13)
1167 sanitize_global_limit(&max_user_bgreq);
1168 sanitize_global_limit(&max_user_congthresh);
1170 spin_lock(&fc->bg_lock);
1171 if (arg->max_background) {
1172 fc->max_background = arg->max_background;
1174 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1175 fc->max_background = max_user_bgreq;
1177 if (arg->congestion_threshold) {
1178 fc->congestion_threshold = arg->congestion_threshold;
1180 if (!cap_sys_admin &&
1181 fc->congestion_threshold > max_user_congthresh)
1182 fc->congestion_threshold = max_user_congthresh;
1184 spin_unlock(&fc->bg_lock);
1187 struct fuse_init_args {
1188 struct fuse_args args;
1189 struct fuse_init_in in;
1190 struct fuse_init_out out;
1193 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1196 struct fuse_conn *fc = fm->fc;
1197 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1198 struct fuse_init_out *arg = &ia->out;
1201 if (error || arg->major != FUSE_KERNEL_VERSION)
1204 unsigned long ra_pages;
1206 process_init_limits(fc, arg);
1208 if (arg->minor >= 6) {
1209 u64 flags = arg->flags;
1211 if (flags & FUSE_INIT_EXT)
1212 flags |= (u64) arg->flags2 << 32;
1214 ra_pages = arg->max_readahead / PAGE_SIZE;
1215 if (flags & FUSE_ASYNC_READ)
1217 if (!(flags & FUSE_POSIX_LOCKS))
1219 if (arg->minor >= 17) {
1220 if (!(flags & FUSE_FLOCK_LOCKS))
1223 if (!(flags & FUSE_POSIX_LOCKS))
1226 if (flags & FUSE_ATOMIC_O_TRUNC)
1227 fc->atomic_o_trunc = 1;
1228 if (arg->minor >= 9) {
1229 /* LOOKUP has dependency on proto version */
1230 if (flags & FUSE_EXPORT_SUPPORT)
1231 fc->export_support = 1;
1233 if (flags & FUSE_BIG_WRITES)
1235 if (flags & FUSE_DONT_MASK)
1237 if (flags & FUSE_AUTO_INVAL_DATA)
1238 fc->auto_inval_data = 1;
1239 else if (flags & FUSE_EXPLICIT_INVAL_DATA)
1240 fc->explicit_inval_data = 1;
1241 if (flags & FUSE_DO_READDIRPLUS) {
1242 fc->do_readdirplus = 1;
1243 if (flags & FUSE_READDIRPLUS_AUTO)
1244 fc->readdirplus_auto = 1;
1246 if (flags & FUSE_ASYNC_DIO)
1248 if (flags & FUSE_WRITEBACK_CACHE)
1249 fc->writeback_cache = 1;
1250 if (flags & FUSE_PARALLEL_DIROPS)
1251 fc->parallel_dirops = 1;
1252 if (flags & FUSE_HANDLE_KILLPRIV)
1253 fc->handle_killpriv = 1;
1254 if (arg->time_gran && arg->time_gran <= 1000000000)
1255 fm->sb->s_time_gran = arg->time_gran;
1256 if ((flags & FUSE_POSIX_ACL)) {
1257 fc->default_permissions = 1;
1260 if (flags & FUSE_CACHE_SYMLINKS)
1261 fc->cache_symlinks = 1;
1262 if (flags & FUSE_ABORT_ERROR)
1264 if (flags & FUSE_MAX_PAGES) {
1266 min_t(unsigned int, fc->max_pages_limit,
1267 max_t(unsigned int, arg->max_pages, 1));
1269 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1270 if (flags & FUSE_MAP_ALIGNMENT &&
1271 !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1274 if (flags & FUSE_HAS_INODE_DAX)
1277 if (flags & FUSE_HANDLE_KILLPRIV_V2) {
1278 fc->handle_killpriv_v2 = 1;
1279 fm->sb->s_flags |= SB_NOSEC;
1281 if (flags & FUSE_SETXATTR_EXT)
1282 fc->setxattr_ext = 1;
1283 if (flags & FUSE_SECURITY_CTX)
1284 fc->init_security = 1;
1285 if (flags & FUSE_CREATE_SUPP_GROUP)
1286 fc->create_supp_group = 1;
1287 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP)
1288 fc->direct_io_allow_mmap = 1;
1290 ra_pages = fc->max_read / PAGE_SIZE;
1295 fm->sb->s_bdi->ra_pages =
1296 min(fm->sb->s_bdi->ra_pages, ra_pages);
1297 fc->minor = arg->minor;
1298 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1299 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1309 fuse_set_initialized(fc);
1310 wake_up_all(&fc->blocked_waitq);
1313 void fuse_send_init(struct fuse_mount *fm)
1315 struct fuse_init_args *ia;
1318 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1320 ia->in.major = FUSE_KERNEL_VERSION;
1321 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1322 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1324 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1325 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1326 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1327 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1328 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1329 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1330 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1331 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1332 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1333 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
1334 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP |
1335 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP;
1336 #ifdef CONFIG_FUSE_DAX
1338 flags |= FUSE_MAP_ALIGNMENT;
1339 if (fuse_is_inode_dax_mode(fm->fc->dax_mode))
1340 flags |= FUSE_HAS_INODE_DAX;
1342 if (fm->fc->auto_submounts)
1343 flags |= FUSE_SUBMOUNTS;
1345 ia->in.flags = flags;
1346 ia->in.flags2 = flags >> 32;
1348 ia->args.opcode = FUSE_INIT;
1349 ia->args.in_numargs = 1;
1350 ia->args.in_args[0].size = sizeof(ia->in);
1351 ia->args.in_args[0].value = &ia->in;
1352 ia->args.out_numargs = 1;
1353 /* Variable length argument used for backward compatibility
1354 with interface version < 7.5. Rest of init_out is zeroed
1355 by do_get_request(), so a short reply is not a problem */
1356 ia->args.out_argvar = true;
1357 ia->args.out_args[0].size = sizeof(ia->out);
1358 ia->args.out_args[0].value = &ia->out;
1359 ia->args.force = true;
1360 ia->args.nocreds = true;
1361 ia->args.end = process_init_reply;
1363 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1364 process_init_reply(fm, &ia->args, -ENOTCONN);
1366 EXPORT_SYMBOL_GPL(fuse_send_init);
1368 void fuse_free_conn(struct fuse_conn *fc)
1370 WARN_ON(!list_empty(&fc->devices));
1373 EXPORT_SYMBOL_GPL(fuse_free_conn);
1375 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1381 suffix = "-fuseblk";
1383 * sb->s_bdi points to blkdev's bdi however we want to redirect
1384 * it to our private bdi...
1387 sb->s_bdi = &noop_backing_dev_info;
1389 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1390 MINOR(fc->dev), suffix);
1394 /* fuse does it's own writeback accounting */
1395 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1396 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1399 * For a single fuse filesystem use max 1% of dirty +
1400 * writeback threshold.
1402 * This gives about 1M of write buffer for memory maps on a
1403 * machine with 1G and 10% dirty_ratio, which should be more
1406 * Privileged users can raise it by writing to
1408 * /sys/class/bdi/<bdi>/max_ratio
1410 bdi_set_max_ratio(sb->s_bdi, 1);
1415 struct fuse_dev *fuse_dev_alloc(void)
1417 struct fuse_dev *fud;
1418 struct list_head *pq;
1420 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1424 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1430 fud->pq.processing = pq;
1431 fuse_pqueue_init(&fud->pq);
1435 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1437 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1439 fud->fc = fuse_conn_get(fc);
1440 spin_lock(&fc->lock);
1441 list_add_tail(&fud->entry, &fc->devices);
1442 spin_unlock(&fc->lock);
1444 EXPORT_SYMBOL_GPL(fuse_dev_install);
1446 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1448 struct fuse_dev *fud;
1450 fud = fuse_dev_alloc();
1454 fuse_dev_install(fud, fc);
1457 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1459 void fuse_dev_free(struct fuse_dev *fud)
1461 struct fuse_conn *fc = fud->fc;
1464 spin_lock(&fc->lock);
1465 list_del(&fud->entry);
1466 spin_unlock(&fc->lock);
1470 kfree(fud->pq.processing);
1473 EXPORT_SYMBOL_GPL(fuse_dev_free);
1475 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1476 const struct fuse_inode *fi)
1478 struct timespec64 ctime = inode_get_ctime(&fi->inode);
1480 *attr = (struct fuse_attr){
1481 .ino = fi->inode.i_ino,
1482 .size = fi->inode.i_size,
1483 .blocks = fi->inode.i_blocks,
1484 .atime = fi->inode.i_atime.tv_sec,
1485 .mtime = fi->inode.i_mtime.tv_sec,
1486 .ctime = ctime.tv_sec,
1487 .atimensec = fi->inode.i_atime.tv_nsec,
1488 .mtimensec = fi->inode.i_mtime.tv_nsec,
1489 .ctimensec = ctime.tv_nsec,
1490 .mode = fi->inode.i_mode,
1491 .nlink = fi->inode.i_nlink,
1492 .uid = fi->inode.i_uid.val,
1493 .gid = fi->inode.i_gid.val,
1494 .rdev = fi->inode.i_rdev,
1495 .blksize = 1u << fi->inode.i_blkbits,
1499 static void fuse_sb_defaults(struct super_block *sb)
1501 sb->s_magic = FUSE_SUPER_MAGIC;
1502 sb->s_op = &fuse_super_operations;
1503 sb->s_xattr = fuse_xattr_handlers;
1504 sb->s_maxbytes = MAX_LFS_FILESIZE;
1505 sb->s_time_gran = 1;
1506 sb->s_export_op = &fuse_export_operations;
1507 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1508 if (sb->s_user_ns != &init_user_ns)
1509 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1510 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1513 static int fuse_fill_super_submount(struct super_block *sb,
1514 struct fuse_inode *parent_fi)
1516 struct fuse_mount *fm = get_fuse_mount_super(sb);
1517 struct super_block *parent_sb = parent_fi->inode.i_sb;
1518 struct fuse_attr root_attr;
1520 struct fuse_submount_lookup *sl;
1521 struct fuse_inode *fi;
1523 fuse_sb_defaults(sb);
1526 WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1527 sb->s_bdi = bdi_get(parent_sb->s_bdi);
1529 sb->s_xattr = parent_sb->s_xattr;
1530 sb->s_time_gran = parent_sb->s_time_gran;
1531 sb->s_blocksize = parent_sb->s_blocksize;
1532 sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1533 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1534 if (parent_sb->s_subtype && !sb->s_subtype)
1537 fuse_fill_attr_from_inode(&root_attr, parent_fi);
1538 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1540 * This inode is just a duplicate, so it is not looked up and
1541 * its nlookup should not be incremented. fuse_iget() does
1542 * that, though, so undo it here.
1544 fi = get_fuse_inode(root);
1547 sb->s_d_op = &fuse_dentry_operations;
1548 sb->s_root = d_make_root(root);
1553 * Grab the parent's submount_lookup pointer and take a
1554 * reference on the shared nlookup from the parent. This is to
1555 * prevent the last forget for this nodeid from getting
1556 * triggered until all users have finished with it.
1558 sl = parent_fi->submount_lookup;
1561 refcount_inc(&sl->count);
1562 fi->submount_lookup = sl;
1568 /* Filesystem context private data holds the FUSE inode of the mount point */
1569 static int fuse_get_tree_submount(struct fs_context *fsc)
1571 struct fuse_mount *fm;
1572 struct fuse_inode *mp_fi = fsc->fs_private;
1573 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1574 struct super_block *sb;
1577 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1581 fm->fc = fuse_conn_get(fc);
1582 fsc->s_fs_info = fm;
1583 sb = sget_fc(fsc, NULL, set_anon_super_fc);
1585 fuse_mount_destroy(fm);
1589 /* Initialize superblock, making @mp_fi its root */
1590 err = fuse_fill_super_submount(sb, mp_fi);
1592 deactivate_locked_super(sb);
1596 down_write(&fc->killsb);
1597 list_add_tail(&fm->fc_entry, &fc->mounts);
1598 up_write(&fc->killsb);
1600 sb->s_flags |= SB_ACTIVE;
1601 fsc->root = dget(sb->s_root);
1606 static const struct fs_context_operations fuse_context_submount_ops = {
1607 .get_tree = fuse_get_tree_submount,
1610 int fuse_init_fs_context_submount(struct fs_context *fsc)
1612 fsc->ops = &fuse_context_submount_ops;
1615 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1617 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1619 struct fuse_dev *fud = NULL;
1620 struct fuse_mount *fm = get_fuse_mount_super(sb);
1621 struct fuse_conn *fc = fm->fc;
1623 struct dentry *root_dentry;
1627 if (sb->s_flags & SB_MANDLOCK)
1630 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1631 fuse_sb_defaults(sb);
1636 if (!sb_set_blocksize(sb, ctx->blksize))
1640 sb->s_blocksize = PAGE_SIZE;
1641 sb->s_blocksize_bits = PAGE_SHIFT;
1644 sb->s_subtype = ctx->subtype;
1645 ctx->subtype = NULL;
1646 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1647 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev);
1654 fud = fuse_dev_alloc_install(fc);
1659 fc->dev = sb->s_dev;
1661 err = fuse_bdi_init(fc, sb);
1665 /* Handle umasking inside the fuse code */
1666 if (sb->s_flags & SB_POSIXACL)
1668 sb->s_flags |= SB_POSIXACL;
1670 fc->default_permissions = ctx->default_permissions;
1671 fc->allow_other = ctx->allow_other;
1672 fc->user_id = ctx->user_id;
1673 fc->group_id = ctx->group_id;
1674 fc->legacy_opts_show = ctx->legacy_opts_show;
1675 fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1676 fc->destroy = ctx->destroy;
1677 fc->no_control = ctx->no_control;
1678 fc->no_force_umount = ctx->no_force_umount;
1681 root = fuse_get_root_inode(sb, ctx->rootmode);
1682 sb->s_d_op = &fuse_root_dentry_operations;
1683 root_dentry = d_make_root(root);
1686 /* Root dentry doesn't have .d_revalidate */
1687 sb->s_d_op = &fuse_dentry_operations;
1689 mutex_lock(&fuse_mutex);
1691 if (ctx->fudptr && *ctx->fudptr)
1694 err = fuse_ctl_add_conn(fc);
1698 list_add_tail(&fc->entry, &fuse_conn_list);
1699 sb->s_root = root_dentry;
1702 mutex_unlock(&fuse_mutex);
1706 mutex_unlock(&fuse_mutex);
1712 if (IS_ENABLED(CONFIG_FUSE_DAX))
1713 fuse_dax_conn_free(fc);
1717 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1719 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1721 struct fuse_fs_context *ctx = fsc->fs_private;
1724 if (!ctx->file || !ctx->rootmode_present ||
1725 !ctx->user_id_present || !ctx->group_id_present)
1729 * Require mount to happen from the same user namespace which
1730 * opened /dev/fuse to prevent potential attacks.
1732 if ((ctx->file->f_op != &fuse_dev_operations) ||
1733 (ctx->file->f_cred->user_ns != sb->s_user_ns))
1735 ctx->fudptr = &ctx->file->private_data;
1737 err = fuse_fill_super_common(sb, ctx);
1740 /* file->private_data shall be visible on all CPUs after this */
1742 fuse_send_init(get_fuse_mount_super(sb));
1747 * This is the path where user supplied an already initialized fuse dev. In
1748 * this case never create a new super if the old one is gone.
1750 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1755 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1758 return fsc->sget_key == get_fuse_conn_super(sb);
1761 static int fuse_get_tree(struct fs_context *fsc)
1763 struct fuse_fs_context *ctx = fsc->fs_private;
1764 struct fuse_dev *fud;
1765 struct fuse_conn *fc;
1766 struct fuse_mount *fm;
1767 struct super_block *sb;
1770 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1774 fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1780 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1781 fc->release = fuse_free_conn;
1783 fsc->s_fs_info = fm;
1785 if (ctx->fd_present)
1786 ctx->file = fget(ctx->fd);
1788 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1789 err = get_tree_bdev(fsc, fuse_fill_super);
1793 * While block dev mount can be initialized with a dummy device fd
1794 * (found by device name), normal fuse mounts can't
1801 * Allow creating a fuse mount with an already initialized fuse
1804 fud = READ_ONCE(ctx->file->private_data);
1805 if (ctx->file->f_op == &fuse_dev_operations && fud) {
1806 fsc->sget_key = fud->fc;
1807 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1808 err = PTR_ERR_OR_ZERO(sb);
1810 fsc->root = dget(sb->s_root);
1812 err = get_tree_nodev(fsc, fuse_fill_super);
1816 fuse_mount_destroy(fm);
1822 static const struct fs_context_operations fuse_context_ops = {
1823 .free = fuse_free_fsc,
1824 .parse_param = fuse_parse_param,
1825 .reconfigure = fuse_reconfigure,
1826 .get_tree = fuse_get_tree,
1830 * Set up the filesystem mount context.
1832 static int fuse_init_fs_context(struct fs_context *fsc)
1834 struct fuse_fs_context *ctx;
1836 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1841 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1842 ctx->legacy_opts_show = true;
1845 if (fsc->fs_type == &fuseblk_fs_type) {
1846 ctx->is_bdev = true;
1847 ctx->destroy = true;
1851 fsc->fs_private = ctx;
1852 fsc->ops = &fuse_context_ops;
1856 bool fuse_mount_remove(struct fuse_mount *fm)
1858 struct fuse_conn *fc = fm->fc;
1861 down_write(&fc->killsb);
1862 list_del_init(&fm->fc_entry);
1863 if (list_empty(&fc->mounts))
1865 up_write(&fc->killsb);
1869 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1871 void fuse_conn_destroy(struct fuse_mount *fm)
1873 struct fuse_conn *fc = fm->fc;
1876 fuse_send_destroy(fm);
1878 fuse_abort_conn(fc);
1879 fuse_wait_aborted(fc);
1881 if (!list_empty(&fc->entry)) {
1882 mutex_lock(&fuse_mutex);
1883 list_del(&fc->entry);
1884 fuse_ctl_remove_conn(fc);
1885 mutex_unlock(&fuse_mutex);
1888 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1890 static void fuse_sb_destroy(struct super_block *sb)
1892 struct fuse_mount *fm = get_fuse_mount_super(sb);
1896 last = fuse_mount_remove(fm);
1898 fuse_conn_destroy(fm);
1902 void fuse_mount_destroy(struct fuse_mount *fm)
1904 fuse_conn_put(fm->fc);
1907 EXPORT_SYMBOL(fuse_mount_destroy);
1909 static void fuse_kill_sb_anon(struct super_block *sb)
1911 fuse_sb_destroy(sb);
1912 kill_anon_super(sb);
1913 fuse_mount_destroy(get_fuse_mount_super(sb));
1916 static struct file_system_type fuse_fs_type = {
1917 .owner = THIS_MODULE,
1919 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1920 .init_fs_context = fuse_init_fs_context,
1921 .parameters = fuse_fs_parameters,
1922 .kill_sb = fuse_kill_sb_anon,
1924 MODULE_ALIAS_FS("fuse");
1927 static void fuse_kill_sb_blk(struct super_block *sb)
1929 fuse_sb_destroy(sb);
1930 kill_block_super(sb);
1931 fuse_mount_destroy(get_fuse_mount_super(sb));
1934 static struct file_system_type fuseblk_fs_type = {
1935 .owner = THIS_MODULE,
1937 .init_fs_context = fuse_init_fs_context,
1938 .parameters = fuse_fs_parameters,
1939 .kill_sb = fuse_kill_sb_blk,
1940 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1942 MODULE_ALIAS_FS("fuseblk");
1944 static inline int register_fuseblk(void)
1946 return register_filesystem(&fuseblk_fs_type);
1949 static inline void unregister_fuseblk(void)
1951 unregister_filesystem(&fuseblk_fs_type);
1954 static inline int register_fuseblk(void)
1959 static inline void unregister_fuseblk(void)
1964 static void fuse_inode_init_once(void *foo)
1966 struct inode *inode = foo;
1968 inode_init_once(inode);
1971 static int __init fuse_fs_init(void)
1975 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1976 sizeof(struct fuse_inode), 0,
1977 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1978 fuse_inode_init_once);
1980 if (!fuse_inode_cachep)
1983 err = register_fuseblk();
1987 err = register_filesystem(&fuse_fs_type);
1994 unregister_fuseblk();
1996 kmem_cache_destroy(fuse_inode_cachep);
2001 static void fuse_fs_cleanup(void)
2003 unregister_filesystem(&fuse_fs_type);
2004 unregister_fuseblk();
2007 * Make sure all delayed rcu free inodes are flushed before we
2011 kmem_cache_destroy(fuse_inode_cachep);
2014 static struct kobject *fuse_kobj;
2016 static int fuse_sysfs_init(void)
2020 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
2026 err = sysfs_create_mount_point(fuse_kobj, "connections");
2028 goto out_fuse_unregister;
2032 out_fuse_unregister:
2033 kobject_put(fuse_kobj);
2038 static void fuse_sysfs_cleanup(void)
2040 sysfs_remove_mount_point(fuse_kobj, "connections");
2041 kobject_put(fuse_kobj);
2044 static int __init fuse_init(void)
2048 pr_info("init (API version %i.%i)\n",
2049 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
2051 INIT_LIST_HEAD(&fuse_conn_list);
2052 res = fuse_fs_init();
2056 res = fuse_dev_init();
2058 goto err_fs_cleanup;
2060 res = fuse_sysfs_init();
2062 goto err_dev_cleanup;
2064 res = fuse_ctl_init();
2066 goto err_sysfs_cleanup;
2068 sanitize_global_limit(&max_user_bgreq);
2069 sanitize_global_limit(&max_user_congthresh);
2074 fuse_sysfs_cleanup();
2083 static void __exit fuse_exit(void)
2088 fuse_sysfs_cleanup();
2093 module_init(fuse_init);
2094 module_exit(fuse_exit);