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Linux/fs/fuse/inode.c

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  1 /*
  2   FUSE: Filesystem in Userspace
  3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
  4 
  5   This program can be distributed under the terms of the GNU GPL.
  6   See the file COPYING.
  7 */
  8 
  9 #include "fuse_i.h"
 10 
 11 #include <linux/pagemap.h>
 12 #include <linux/slab.h>
 13 #include <linux/file.h>
 14 #include <linux/seq_file.h>
 15 #include <linux/init.h>
 16 #include <linux/module.h>
 17 #include <linux/moduleparam.h>
 18 #include <linux/parser.h>
 19 #include <linux/statfs.h>
 20 #include <linux/random.h>
 21 #include <linux/sched.h>
 22 #include <linux/exportfs.h>
 23 #include <linux/posix_acl.h>
 24 #include <linux/pid_namespace.h>
 25 
 26 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 27 MODULE_DESCRIPTION("Filesystem in Userspace");
 28 MODULE_LICENSE("GPL");
 29 
 30 static struct kmem_cache *fuse_inode_cachep;
 31 struct list_head fuse_conn_list;
 32 DEFINE_MUTEX(fuse_mutex);
 33 
 34 static int set_global_limit(const char *val, const struct kernel_param *kp);
 35 
 36 unsigned max_user_bgreq;
 37 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
 38                   &max_user_bgreq, 0644);
 39 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
 40 MODULE_PARM_DESC(max_user_bgreq,
 41  "Global limit for the maximum number of backgrounded requests an "
 42  "unprivileged user can set");
 43 
 44 unsigned max_user_congthresh;
 45 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
 46                   &max_user_congthresh, 0644);
 47 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
 48 MODULE_PARM_DESC(max_user_congthresh,
 49  "Global limit for the maximum congestion threshold an "
 50  "unprivileged user can set");
 51 
 52 #define FUSE_SUPER_MAGIC 0x65735546
 53 
 54 #define FUSE_DEFAULT_BLKSIZE 512
 55 
 56 /** Maximum number of outstanding background requests */
 57 #define FUSE_DEFAULT_MAX_BACKGROUND 12
 58 
 59 /** Congestion starts at 75% of maximum */
 60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
 61 
 62 struct fuse_mount_data {
 63         int fd;
 64         unsigned rootmode;
 65         kuid_t user_id;
 66         kgid_t group_id;
 67         unsigned fd_present:1;
 68         unsigned rootmode_present:1;
 69         unsigned user_id_present:1;
 70         unsigned group_id_present:1;
 71         unsigned default_permissions:1;
 72         unsigned allow_other:1;
 73         unsigned max_read;
 74         unsigned blksize;
 75 };
 76 
 77 struct fuse_forget_link *fuse_alloc_forget(void)
 78 {
 79         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
 80 }
 81 
 82 static struct inode *fuse_alloc_inode(struct super_block *sb)
 83 {
 84         struct fuse_inode *fi;
 85 
 86         fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
 87         if (!fi)
 88                 return NULL;
 89 
 90         fi->i_time = 0;
 91         fi->inval_mask = 0;
 92         fi->nodeid = 0;
 93         fi->nlookup = 0;
 94         fi->attr_version = 0;
 95         fi->orig_ino = 0;
 96         fi->state = 0;
 97         mutex_init(&fi->mutex);
 98         spin_lock_init(&fi->lock);
 99         fi->forget = fuse_alloc_forget();
100         if (!fi->forget) {
101                 kmem_cache_free(fuse_inode_cachep, fi);
102                 return NULL;
103         }
104 
105         return &fi->inode;
106 }
107 
108 static void fuse_free_inode(struct inode *inode)
109 {
110         struct fuse_inode *fi = get_fuse_inode(inode);
111 
112         mutex_destroy(&fi->mutex);
113         kfree(fi->forget);
114         kmem_cache_free(fuse_inode_cachep, fi);
115 }
116 
117 static void fuse_evict_inode(struct inode *inode)
118 {
119         struct fuse_inode *fi = get_fuse_inode(inode);
120 
121         truncate_inode_pages_final(&inode->i_data);
122         clear_inode(inode);
123         if (inode->i_sb->s_flags & SB_ACTIVE) {
124                 struct fuse_conn *fc = get_fuse_conn(inode);
125                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
126                 fi->forget = NULL;
127         }
128         if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {
129                 WARN_ON(!list_empty(&fi->write_files));
130                 WARN_ON(!list_empty(&fi->queued_writes));
131         }
132 }
133 
134 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
135 {
136         sync_filesystem(sb);
137         if (*flags & SB_MANDLOCK)
138                 return -EINVAL;
139 
140         return 0;
141 }
142 
143 /*
144  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
145  * so that it will fit.
146  */
147 static ino_t fuse_squash_ino(u64 ino64)
148 {
149         ino_t ino = (ino_t) ino64;
150         if (sizeof(ino_t) < sizeof(u64))
151                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
152         return ino;
153 }
154 
155 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
156                                    u64 attr_valid)
157 {
158         struct fuse_conn *fc = get_fuse_conn(inode);
159         struct fuse_inode *fi = get_fuse_inode(inode);
160 
161         lockdep_assert_held(&fi->lock);
162 
163         fi->attr_version = atomic64_inc_return(&fc->attr_version);
164         fi->i_time = attr_valid;
165         WRITE_ONCE(fi->inval_mask, 0);
166 
167         inode->i_ino     = fuse_squash_ino(attr->ino);
168         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
169         set_nlink(inode, attr->nlink);
170         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
171         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
172         inode->i_blocks  = attr->blocks;
173         inode->i_atime.tv_sec   = attr->atime;
174         inode->i_atime.tv_nsec  = attr->atimensec;
175         /* mtime from server may be stale due to local buffered write */
176         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
177                 inode->i_mtime.tv_sec   = attr->mtime;
178                 inode->i_mtime.tv_nsec  = attr->mtimensec;
179                 inode->i_ctime.tv_sec   = attr->ctime;
180                 inode->i_ctime.tv_nsec  = attr->ctimensec;
181         }
182 
183         if (attr->blksize != 0)
184                 inode->i_blkbits = ilog2(attr->blksize);
185         else
186                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
187 
188         /*
189          * Don't set the sticky bit in i_mode, unless we want the VFS
190          * to check permissions.  This prevents failures due to the
191          * check in may_delete().
192          */
193         fi->orig_i_mode = inode->i_mode;
194         if (!fc->default_permissions)
195                 inode->i_mode &= ~S_ISVTX;
196 
197         fi->orig_ino = attr->ino;
198 }
199 
200 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
201                             u64 attr_valid, u64 attr_version)
202 {
203         struct fuse_conn *fc = get_fuse_conn(inode);
204         struct fuse_inode *fi = get_fuse_inode(inode);
205         bool is_wb = fc->writeback_cache;
206         loff_t oldsize;
207         struct timespec64 old_mtime;
208 
209         spin_lock(&fi->lock);
210         if ((attr_version != 0 && fi->attr_version > attr_version) ||
211             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
212                 spin_unlock(&fi->lock);
213                 return;
214         }
215 
216         old_mtime = inode->i_mtime;
217         fuse_change_attributes_common(inode, attr, attr_valid);
218 
219         oldsize = inode->i_size;
220         /*
221          * In case of writeback_cache enabled, the cached writes beyond EOF
222          * extend local i_size without keeping userspace server in sync. So,
223          * attr->size coming from server can be stale. We cannot trust it.
224          */
225         if (!is_wb || !S_ISREG(inode->i_mode))
226                 i_size_write(inode, attr->size);
227         spin_unlock(&fi->lock);
228 
229         if (!is_wb && S_ISREG(inode->i_mode)) {
230                 bool inval = false;
231 
232                 if (oldsize != attr->size) {
233                         truncate_pagecache(inode, attr->size);
234                         if (!fc->explicit_inval_data)
235                                 inval = true;
236                 } else if (fc->auto_inval_data) {
237                         struct timespec64 new_mtime = {
238                                 .tv_sec = attr->mtime,
239                                 .tv_nsec = attr->mtimensec,
240                         };
241 
242                         /*
243                          * Auto inval mode also checks and invalidates if mtime
244                          * has changed.
245                          */
246                         if (!timespec64_equal(&old_mtime, &new_mtime))
247                                 inval = true;
248                 }
249 
250                 if (inval)
251                         invalidate_inode_pages2(inode->i_mapping);
252         }
253 }
254 
255 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
256 {
257         inode->i_mode = attr->mode & S_IFMT;
258         inode->i_size = attr->size;
259         inode->i_mtime.tv_sec  = attr->mtime;
260         inode->i_mtime.tv_nsec = attr->mtimensec;
261         inode->i_ctime.tv_sec  = attr->ctime;
262         inode->i_ctime.tv_nsec = attr->ctimensec;
263         if (S_ISREG(inode->i_mode)) {
264                 fuse_init_common(inode);
265                 fuse_init_file_inode(inode);
266         } else if (S_ISDIR(inode->i_mode))
267                 fuse_init_dir(inode);
268         else if (S_ISLNK(inode->i_mode))
269                 fuse_init_symlink(inode);
270         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
271                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
272                 fuse_init_common(inode);
273                 init_special_inode(inode, inode->i_mode,
274                                    new_decode_dev(attr->rdev));
275         } else
276                 BUG();
277 }
278 
279 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
280 {
281         u64 nodeid = *(u64 *) _nodeidp;
282         if (get_node_id(inode) == nodeid)
283                 return 1;
284         else
285                 return 0;
286 }
287 
288 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
289 {
290         u64 nodeid = *(u64 *) _nodeidp;
291         get_fuse_inode(inode)->nodeid = nodeid;
292         return 0;
293 }
294 
295 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
296                         int generation, struct fuse_attr *attr,
297                         u64 attr_valid, u64 attr_version)
298 {
299         struct inode *inode;
300         struct fuse_inode *fi;
301         struct fuse_conn *fc = get_fuse_conn_super(sb);
302 
303  retry:
304         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
305         if (!inode)
306                 return NULL;
307 
308         if ((inode->i_state & I_NEW)) {
309                 inode->i_flags |= S_NOATIME;
310                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
311                         inode->i_flags |= S_NOCMTIME;
312                 inode->i_generation = generation;
313                 fuse_init_inode(inode, attr);
314                 unlock_new_inode(inode);
315         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
316                 /* Inode has changed type, any I/O on the old should fail */
317                 make_bad_inode(inode);
318                 iput(inode);
319                 goto retry;
320         }
321 
322         fi = get_fuse_inode(inode);
323         spin_lock(&fi->lock);
324         fi->nlookup++;
325         spin_unlock(&fi->lock);
326         fuse_change_attributes(inode, attr, attr_valid, attr_version);
327 
328         return inode;
329 }
330 
331 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
332                              loff_t offset, loff_t len)
333 {
334         struct inode *inode;
335         pgoff_t pg_start;
336         pgoff_t pg_end;
337 
338         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
339         if (!inode)
340                 return -ENOENT;
341 
342         fuse_invalidate_attr(inode);
343         forget_all_cached_acls(inode);
344         if (offset >= 0) {
345                 pg_start = offset >> PAGE_SHIFT;
346                 if (len <= 0)
347                         pg_end = -1;
348                 else
349                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
350                 invalidate_inode_pages2_range(inode->i_mapping,
351                                               pg_start, pg_end);
352         }
353         iput(inode);
354         return 0;
355 }
356 
357 bool fuse_lock_inode(struct inode *inode)
358 {
359         bool locked = false;
360 
361         if (!get_fuse_conn(inode)->parallel_dirops) {
362                 mutex_lock(&get_fuse_inode(inode)->mutex);
363                 locked = true;
364         }
365 
366         return locked;
367 }
368 
369 void fuse_unlock_inode(struct inode *inode, bool locked)
370 {
371         if (locked)
372                 mutex_unlock(&get_fuse_inode(inode)->mutex);
373 }
374 
375 static void fuse_umount_begin(struct super_block *sb)
376 {
377         fuse_abort_conn(get_fuse_conn_super(sb));
378 }
379 
380 static void fuse_send_destroy(struct fuse_conn *fc)
381 {
382         struct fuse_req *req = fc->destroy_req;
383         if (req && fc->conn_init) {
384                 fc->destroy_req = NULL;
385                 req->in.h.opcode = FUSE_DESTROY;
386                 __set_bit(FR_FORCE, &req->flags);
387                 __clear_bit(FR_BACKGROUND, &req->flags);
388                 fuse_request_send(fc, req);
389                 fuse_put_request(fc, req);
390         }
391 }
392 
393 static void fuse_put_super(struct super_block *sb)
394 {
395         struct fuse_conn *fc = get_fuse_conn_super(sb);
396 
397         mutex_lock(&fuse_mutex);
398         list_del(&fc->entry);
399         fuse_ctl_remove_conn(fc);
400         mutex_unlock(&fuse_mutex);
401 
402         fuse_conn_put(fc);
403 }
404 
405 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
406 {
407         stbuf->f_type    = FUSE_SUPER_MAGIC;
408         stbuf->f_bsize   = attr->bsize;
409         stbuf->f_frsize  = attr->frsize;
410         stbuf->f_blocks  = attr->blocks;
411         stbuf->f_bfree   = attr->bfree;
412         stbuf->f_bavail  = attr->bavail;
413         stbuf->f_files   = attr->files;
414         stbuf->f_ffree   = attr->ffree;
415         stbuf->f_namelen = attr->namelen;
416         /* fsid is left zero */
417 }
418 
419 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
420 {
421         struct super_block *sb = dentry->d_sb;
422         struct fuse_conn *fc = get_fuse_conn_super(sb);
423         FUSE_ARGS(args);
424         struct fuse_statfs_out outarg;
425         int err;
426 
427         if (!fuse_allow_current_process(fc)) {
428                 buf->f_type = FUSE_SUPER_MAGIC;
429                 return 0;
430         }
431 
432         memset(&outarg, 0, sizeof(outarg));
433         args.in.numargs = 0;
434         args.in.h.opcode = FUSE_STATFS;
435         args.in.h.nodeid = get_node_id(d_inode(dentry));
436         args.out.numargs = 1;
437         args.out.args[0].size = sizeof(outarg);
438         args.out.args[0].value = &outarg;
439         err = fuse_simple_request(fc, &args);
440         if (!err)
441                 convert_fuse_statfs(buf, &outarg.st);
442         return err;
443 }
444 
445 enum {
446         OPT_FD,
447         OPT_ROOTMODE,
448         OPT_USER_ID,
449         OPT_GROUP_ID,
450         OPT_DEFAULT_PERMISSIONS,
451         OPT_ALLOW_OTHER,
452         OPT_MAX_READ,
453         OPT_BLKSIZE,
454         OPT_ERR
455 };
456 
457 static const match_table_t tokens = {
458         {OPT_FD,                        "fd=%u"},
459         {OPT_ROOTMODE,                  "rootmode=%o"},
460         {OPT_USER_ID,                   "user_id=%u"},
461         {OPT_GROUP_ID,                  "group_id=%u"},
462         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
463         {OPT_ALLOW_OTHER,               "allow_other"},
464         {OPT_MAX_READ,                  "max_read=%u"},
465         {OPT_BLKSIZE,                   "blksize=%u"},
466         {OPT_ERR,                       NULL}
467 };
468 
469 static int fuse_match_uint(substring_t *s, unsigned int *res)
470 {
471         int err = -ENOMEM;
472         char *buf = match_strdup(s);
473         if (buf) {
474                 err = kstrtouint(buf, 10, res);
475                 kfree(buf);
476         }
477         return err;
478 }
479 
480 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
481                           struct user_namespace *user_ns)
482 {
483         char *p;
484         memset(d, 0, sizeof(struct fuse_mount_data));
485         d->max_read = ~0;
486         d->blksize = FUSE_DEFAULT_BLKSIZE;
487 
488         while ((p = strsep(&opt, ",")) != NULL) {
489                 int token;
490                 int value;
491                 unsigned uv;
492                 substring_t args[MAX_OPT_ARGS];
493                 if (!*p)
494                         continue;
495 
496                 token = match_token(p, tokens, args);
497                 switch (token) {
498                 case OPT_FD:
499                         if (match_int(&args[0], &value))
500                                 return 0;
501                         d->fd = value;
502                         d->fd_present = 1;
503                         break;
504 
505                 case OPT_ROOTMODE:
506                         if (match_octal(&args[0], &value))
507                                 return 0;
508                         if (!fuse_valid_type(value))
509                                 return 0;
510                         d->rootmode = value;
511                         d->rootmode_present = 1;
512                         break;
513 
514                 case OPT_USER_ID:
515                         if (fuse_match_uint(&args[0], &uv))
516                                 return 0;
517                         d->user_id = make_kuid(user_ns, uv);
518                         if (!uid_valid(d->user_id))
519                                 return 0;
520                         d->user_id_present = 1;
521                         break;
522 
523                 case OPT_GROUP_ID:
524                         if (fuse_match_uint(&args[0], &uv))
525                                 return 0;
526                         d->group_id = make_kgid(user_ns, uv);
527                         if (!gid_valid(d->group_id))
528                                 return 0;
529                         d->group_id_present = 1;
530                         break;
531 
532                 case OPT_DEFAULT_PERMISSIONS:
533                         d->default_permissions = 1;
534                         break;
535 
536                 case OPT_ALLOW_OTHER:
537                         d->allow_other = 1;
538                         break;
539 
540                 case OPT_MAX_READ:
541                         if (match_int(&args[0], &value))
542                                 return 0;
543                         d->max_read = value;
544                         break;
545 
546                 case OPT_BLKSIZE:
547                         if (!is_bdev || match_int(&args[0], &value))
548                                 return 0;
549                         d->blksize = value;
550                         break;
551 
552                 default:
553                         return 0;
554                 }
555         }
556 
557         if (!d->fd_present || !d->rootmode_present ||
558             !d->user_id_present || !d->group_id_present)
559                 return 0;
560 
561         return 1;
562 }
563 
564 static int fuse_show_options(struct seq_file *m, struct dentry *root)
565 {
566         struct super_block *sb = root->d_sb;
567         struct fuse_conn *fc = get_fuse_conn_super(sb);
568 
569         seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
570         seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
571         if (fc->default_permissions)
572                 seq_puts(m, ",default_permissions");
573         if (fc->allow_other)
574                 seq_puts(m, ",allow_other");
575         if (fc->max_read != ~0)
576                 seq_printf(m, ",max_read=%u", fc->max_read);
577         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
578                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
579         return 0;
580 }
581 
582 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
583 {
584         memset(fiq, 0, sizeof(struct fuse_iqueue));
585         spin_lock_init(&fiq->lock);
586         init_waitqueue_head(&fiq->waitq);
587         INIT_LIST_HEAD(&fiq->pending);
588         INIT_LIST_HEAD(&fiq->interrupts);
589         fiq->forget_list_tail = &fiq->forget_list_head;
590         fiq->connected = 1;
591 }
592 
593 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
594 {
595         unsigned int i;
596 
597         spin_lock_init(&fpq->lock);
598         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
599                 INIT_LIST_HEAD(&fpq->processing[i]);
600         INIT_LIST_HEAD(&fpq->io);
601         fpq->connected = 1;
602 }
603 
604 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
605 {
606         memset(fc, 0, sizeof(*fc));
607         spin_lock_init(&fc->lock);
608         spin_lock_init(&fc->bg_lock);
609         init_rwsem(&fc->killsb);
610         refcount_set(&fc->count, 1);
611         atomic_set(&fc->dev_count, 1);
612         init_waitqueue_head(&fc->blocked_waitq);
613         init_waitqueue_head(&fc->reserved_req_waitq);
614         fuse_iqueue_init(&fc->iq);
615         INIT_LIST_HEAD(&fc->bg_queue);
616         INIT_LIST_HEAD(&fc->entry);
617         INIT_LIST_HEAD(&fc->devices);
618         atomic_set(&fc->num_waiting, 0);
619         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
620         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
621         atomic64_set(&fc->khctr, 0);
622         fc->polled_files = RB_ROOT;
623         fc->blocked = 0;
624         fc->initialized = 0;
625         fc->connected = 1;
626         atomic64_set(&fc->attr_version, 1);
627         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
628         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
629         fc->user_ns = get_user_ns(user_ns);
630         fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
631 }
632 EXPORT_SYMBOL_GPL(fuse_conn_init);
633 
634 void fuse_conn_put(struct fuse_conn *fc)
635 {
636         if (refcount_dec_and_test(&fc->count)) {
637                 if (fc->destroy_req)
638                         fuse_request_free(fc->destroy_req);
639                 put_pid_ns(fc->pid_ns);
640                 put_user_ns(fc->user_ns);
641                 fc->release(fc);
642         }
643 }
644 EXPORT_SYMBOL_GPL(fuse_conn_put);
645 
646 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
647 {
648         refcount_inc(&fc->count);
649         return fc;
650 }
651 EXPORT_SYMBOL_GPL(fuse_conn_get);
652 
653 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
654 {
655         struct fuse_attr attr;
656         memset(&attr, 0, sizeof(attr));
657 
658         attr.mode = mode;
659         attr.ino = FUSE_ROOT_ID;
660         attr.nlink = 1;
661         return fuse_iget(sb, 1, 0, &attr, 0, 0);
662 }
663 
664 struct fuse_inode_handle {
665         u64 nodeid;
666         u32 generation;
667 };
668 
669 static struct dentry *fuse_get_dentry(struct super_block *sb,
670                                       struct fuse_inode_handle *handle)
671 {
672         struct fuse_conn *fc = get_fuse_conn_super(sb);
673         struct inode *inode;
674         struct dentry *entry;
675         int err = -ESTALE;
676 
677         if (handle->nodeid == 0)
678                 goto out_err;
679 
680         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
681         if (!inode) {
682                 struct fuse_entry_out outarg;
683                 const struct qstr name = QSTR_INIT(".", 1);
684 
685                 if (!fc->export_support)
686                         goto out_err;
687 
688                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
689                                        &inode);
690                 if (err && err != -ENOENT)
691                         goto out_err;
692                 if (err || !inode) {
693                         err = -ESTALE;
694                         goto out_err;
695                 }
696                 err = -EIO;
697                 if (get_node_id(inode) != handle->nodeid)
698                         goto out_iput;
699         }
700         err = -ESTALE;
701         if (inode->i_generation != handle->generation)
702                 goto out_iput;
703 
704         entry = d_obtain_alias(inode);
705         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
706                 fuse_invalidate_entry_cache(entry);
707 
708         return entry;
709 
710  out_iput:
711         iput(inode);
712  out_err:
713         return ERR_PTR(err);
714 }
715 
716 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
717                            struct inode *parent)
718 {
719         int len = parent ? 6 : 3;
720         u64 nodeid;
721         u32 generation;
722 
723         if (*max_len < len) {
724                 *max_len = len;
725                 return  FILEID_INVALID;
726         }
727 
728         nodeid = get_fuse_inode(inode)->nodeid;
729         generation = inode->i_generation;
730 
731         fh[0] = (u32)(nodeid >> 32);
732         fh[1] = (u32)(nodeid & 0xffffffff);
733         fh[2] = generation;
734 
735         if (parent) {
736                 nodeid = get_fuse_inode(parent)->nodeid;
737                 generation = parent->i_generation;
738 
739                 fh[3] = (u32)(nodeid >> 32);
740                 fh[4] = (u32)(nodeid & 0xffffffff);
741                 fh[5] = generation;
742         }
743 
744         *max_len = len;
745         return parent ? 0x82 : 0x81;
746 }
747 
748 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
749                 struct fid *fid, int fh_len, int fh_type)
750 {
751         struct fuse_inode_handle handle;
752 
753         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
754                 return NULL;
755 
756         handle.nodeid = (u64) fid->raw[0] << 32;
757         handle.nodeid |= (u64) fid->raw[1];
758         handle.generation = fid->raw[2];
759         return fuse_get_dentry(sb, &handle);
760 }
761 
762 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
763                 struct fid *fid, int fh_len, int fh_type)
764 {
765         struct fuse_inode_handle parent;
766 
767         if (fh_type != 0x82 || fh_len < 6)
768                 return NULL;
769 
770         parent.nodeid = (u64) fid->raw[3] << 32;
771         parent.nodeid |= (u64) fid->raw[4];
772         parent.generation = fid->raw[5];
773         return fuse_get_dentry(sb, &parent);
774 }
775 
776 static struct dentry *fuse_get_parent(struct dentry *child)
777 {
778         struct inode *child_inode = d_inode(child);
779         struct fuse_conn *fc = get_fuse_conn(child_inode);
780         struct inode *inode;
781         struct dentry *parent;
782         struct fuse_entry_out outarg;
783         const struct qstr name = QSTR_INIT("..", 2);
784         int err;
785 
786         if (!fc->export_support)
787                 return ERR_PTR(-ESTALE);
788 
789         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
790                                &name, &outarg, &inode);
791         if (err) {
792                 if (err == -ENOENT)
793                         return ERR_PTR(-ESTALE);
794                 return ERR_PTR(err);
795         }
796 
797         parent = d_obtain_alias(inode);
798         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
799                 fuse_invalidate_entry_cache(parent);
800 
801         return parent;
802 }
803 
804 static const struct export_operations fuse_export_operations = {
805         .fh_to_dentry   = fuse_fh_to_dentry,
806         .fh_to_parent   = fuse_fh_to_parent,
807         .encode_fh      = fuse_encode_fh,
808         .get_parent     = fuse_get_parent,
809 };
810 
811 static const struct super_operations fuse_super_operations = {
812         .alloc_inode    = fuse_alloc_inode,
813         .free_inode     = fuse_free_inode,
814         .evict_inode    = fuse_evict_inode,
815         .write_inode    = fuse_write_inode,
816         .drop_inode     = generic_delete_inode,
817         .remount_fs     = fuse_remount_fs,
818         .put_super      = fuse_put_super,
819         .umount_begin   = fuse_umount_begin,
820         .statfs         = fuse_statfs,
821         .show_options   = fuse_show_options,
822 };
823 
824 static void sanitize_global_limit(unsigned *limit)
825 {
826         if (*limit == 0)
827                 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) /
828                          sizeof(struct fuse_req);
829 
830         if (*limit >= 1 << 16)
831                 *limit = (1 << 16) - 1;
832 }
833 
834 static int set_global_limit(const char *val, const struct kernel_param *kp)
835 {
836         int rv;
837 
838         rv = param_set_uint(val, kp);
839         if (rv)
840                 return rv;
841 
842         sanitize_global_limit((unsigned *)kp->arg);
843 
844         return 0;
845 }
846 
847 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
848 {
849         int cap_sys_admin = capable(CAP_SYS_ADMIN);
850 
851         if (arg->minor < 13)
852                 return;
853 
854         sanitize_global_limit(&max_user_bgreq);
855         sanitize_global_limit(&max_user_congthresh);
856 
857         spin_lock(&fc->bg_lock);
858         if (arg->max_background) {
859                 fc->max_background = arg->max_background;
860 
861                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
862                         fc->max_background = max_user_bgreq;
863         }
864         if (arg->congestion_threshold) {
865                 fc->congestion_threshold = arg->congestion_threshold;
866 
867                 if (!cap_sys_admin &&
868                     fc->congestion_threshold > max_user_congthresh)
869                         fc->congestion_threshold = max_user_congthresh;
870         }
871         spin_unlock(&fc->bg_lock);
872 }
873 
874 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
875 {
876         struct fuse_init_out *arg = &req->misc.init_out;
877 
878         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
879                 fc->conn_error = 1;
880         else {
881                 unsigned long ra_pages;
882 
883                 process_init_limits(fc, arg);
884 
885                 if (arg->minor >= 6) {
886                         ra_pages = arg->max_readahead / PAGE_SIZE;
887                         if (arg->flags & FUSE_ASYNC_READ)
888                                 fc->async_read = 1;
889                         if (!(arg->flags & FUSE_POSIX_LOCKS))
890                                 fc->no_lock = 1;
891                         if (arg->minor >= 17) {
892                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
893                                         fc->no_flock = 1;
894                         } else {
895                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
896                                         fc->no_flock = 1;
897                         }
898                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
899                                 fc->atomic_o_trunc = 1;
900                         if (arg->minor >= 9) {
901                                 /* LOOKUP has dependency on proto version */
902                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
903                                         fc->export_support = 1;
904                         }
905                         if (arg->flags & FUSE_BIG_WRITES)
906                                 fc->big_writes = 1;
907                         if (arg->flags & FUSE_DONT_MASK)
908                                 fc->dont_mask = 1;
909                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
910                                 fc->auto_inval_data = 1;
911                         else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
912                                 fc->explicit_inval_data = 1;
913                         if (arg->flags & FUSE_DO_READDIRPLUS) {
914                                 fc->do_readdirplus = 1;
915                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
916                                         fc->readdirplus_auto = 1;
917                         }
918                         if (arg->flags & FUSE_ASYNC_DIO)
919                                 fc->async_dio = 1;
920                         if (arg->flags & FUSE_WRITEBACK_CACHE)
921                                 fc->writeback_cache = 1;
922                         if (arg->flags & FUSE_PARALLEL_DIROPS)
923                                 fc->parallel_dirops = 1;
924                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
925                                 fc->handle_killpriv = 1;
926                         if (arg->time_gran && arg->time_gran <= 1000000000)
927                                 fc->sb->s_time_gran = arg->time_gran;
928                         if ((arg->flags & FUSE_POSIX_ACL)) {
929                                 fc->default_permissions = 1;
930                                 fc->posix_acl = 1;
931                                 fc->sb->s_xattr = fuse_acl_xattr_handlers;
932                         }
933                         if (arg->flags & FUSE_CACHE_SYMLINKS)
934                                 fc->cache_symlinks = 1;
935                         if (arg->flags & FUSE_ABORT_ERROR)
936                                 fc->abort_err = 1;
937                         if (arg->flags & FUSE_MAX_PAGES) {
938                                 fc->max_pages =
939                                         min_t(unsigned int, FUSE_MAX_MAX_PAGES,
940                                         max_t(unsigned int, arg->max_pages, 1));
941                         }
942                 } else {
943                         ra_pages = fc->max_read / PAGE_SIZE;
944                         fc->no_lock = 1;
945                         fc->no_flock = 1;
946                 }
947 
948                 fc->sb->s_bdi->ra_pages =
949                                 min(fc->sb->s_bdi->ra_pages, ra_pages);
950                 fc->minor = arg->minor;
951                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
952                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
953                 fc->conn_init = 1;
954         }
955         fuse_set_initialized(fc);
956         wake_up_all(&fc->blocked_waitq);
957 }
958 
959 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
960 {
961         struct fuse_init_in *arg = &req->misc.init_in;
962 
963         arg->major = FUSE_KERNEL_VERSION;
964         arg->minor = FUSE_KERNEL_MINOR_VERSION;
965         arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
966         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
967                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
968                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
969                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
970                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
971                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
972                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
973                 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
974                 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
975         req->in.h.opcode = FUSE_INIT;
976         req->in.numargs = 1;
977         req->in.args[0].size = sizeof(*arg);
978         req->in.args[0].value = arg;
979         req->out.numargs = 1;
980         /* Variable length argument used for backward compatibility
981            with interface version < 7.5.  Rest of init_out is zeroed
982            by do_get_request(), so a short reply is not a problem */
983         req->out.argvar = 1;
984         req->out.args[0].size = sizeof(struct fuse_init_out);
985         req->out.args[0].value = &req->misc.init_out;
986         req->end = process_init_reply;
987         fuse_request_send_background(fc, req);
988 }
989 
990 static void fuse_free_conn(struct fuse_conn *fc)
991 {
992         WARN_ON(!list_empty(&fc->devices));
993         kfree_rcu(fc, rcu);
994 }
995 
996 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
997 {
998         int err;
999         char *suffix = "";
1000 
1001         if (sb->s_bdev) {
1002                 suffix = "-fuseblk";
1003                 /*
1004                  * sb->s_bdi points to blkdev's bdi however we want to redirect
1005                  * it to our private bdi...
1006                  */
1007                 bdi_put(sb->s_bdi);
1008                 sb->s_bdi = &noop_backing_dev_info;
1009         }
1010         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1011                                    MINOR(fc->dev), suffix);
1012         if (err)
1013                 return err;
1014 
1015         sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
1016         /* fuse does it's own writeback accounting */
1017         sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1018 
1019         /*
1020          * For a single fuse filesystem use max 1% of dirty +
1021          * writeback threshold.
1022          *
1023          * This gives about 1M of write buffer for memory maps on a
1024          * machine with 1G and 10% dirty_ratio, which should be more
1025          * than enough.
1026          *
1027          * Privileged users can raise it by writing to
1028          *
1029          *    /sys/class/bdi/<bdi>/max_ratio
1030          */
1031         bdi_set_max_ratio(sb->s_bdi, 1);
1032 
1033         return 0;
1034 }
1035 
1036 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1037 {
1038         struct fuse_dev *fud;
1039         struct list_head *pq;
1040 
1041         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1042         if (!fud)
1043                 return NULL;
1044 
1045         pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1046         if (!pq) {
1047                 kfree(fud);
1048                 return NULL;
1049         }
1050 
1051         fud->pq.processing = pq;
1052         fud->fc = fuse_conn_get(fc);
1053         fuse_pqueue_init(&fud->pq);
1054 
1055         spin_lock(&fc->lock);
1056         list_add_tail(&fud->entry, &fc->devices);
1057         spin_unlock(&fc->lock);
1058 
1059         return fud;
1060 }
1061 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1062 
1063 void fuse_dev_free(struct fuse_dev *fud)
1064 {
1065         struct fuse_conn *fc = fud->fc;
1066 
1067         if (fc) {
1068                 spin_lock(&fc->lock);
1069                 list_del(&fud->entry);
1070                 spin_unlock(&fc->lock);
1071 
1072                 fuse_conn_put(fc);
1073         }
1074         kfree(fud->pq.processing);
1075         kfree(fud);
1076 }
1077 EXPORT_SYMBOL_GPL(fuse_dev_free);
1078 
1079 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1080 {
1081         struct fuse_dev *fud;
1082         struct fuse_conn *fc;
1083         struct inode *root;
1084         struct fuse_mount_data d;
1085         struct file *file;
1086         struct dentry *root_dentry;
1087         struct fuse_req *init_req;
1088         int err;
1089         int is_bdev = sb->s_bdev != NULL;
1090 
1091         err = -EINVAL;
1092         if (sb->s_flags & SB_MANDLOCK)
1093                 goto err;
1094 
1095         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1096 
1097         if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
1098                 goto err;
1099 
1100         if (is_bdev) {
1101 #ifdef CONFIG_BLOCK
1102                 err = -EINVAL;
1103                 if (!sb_set_blocksize(sb, d.blksize))
1104                         goto err;
1105 #endif
1106         } else {
1107                 sb->s_blocksize = PAGE_SIZE;
1108                 sb->s_blocksize_bits = PAGE_SHIFT;
1109         }
1110         sb->s_magic = FUSE_SUPER_MAGIC;
1111         sb->s_op = &fuse_super_operations;
1112         sb->s_xattr = fuse_xattr_handlers;
1113         sb->s_maxbytes = MAX_LFS_FILESIZE;
1114         sb->s_time_gran = 1;
1115         sb->s_export_op = &fuse_export_operations;
1116         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1117         if (sb->s_user_ns != &init_user_ns)
1118                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1119 
1120         file = fget(d.fd);
1121         err = -EINVAL;
1122         if (!file)
1123                 goto err;
1124 
1125         /*
1126          * Require mount to happen from the same user namespace which
1127          * opened /dev/fuse to prevent potential attacks.
1128          */
1129         if (file->f_op != &fuse_dev_operations ||
1130             file->f_cred->user_ns != sb->s_user_ns)
1131                 goto err_fput;
1132 
1133         /*
1134          * If we are not in the initial user namespace posix
1135          * acls must be translated.
1136          */
1137         if (sb->s_user_ns != &init_user_ns)
1138                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1139 
1140         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1141         err = -ENOMEM;
1142         if (!fc)
1143                 goto err_fput;
1144 
1145         fuse_conn_init(fc, sb->s_user_ns);
1146         fc->release = fuse_free_conn;
1147 
1148         fud = fuse_dev_alloc(fc);
1149         if (!fud)
1150                 goto err_put_conn;
1151 
1152         fc->dev = sb->s_dev;
1153         fc->sb = sb;
1154         err = fuse_bdi_init(fc, sb);
1155         if (err)
1156                 goto err_dev_free;
1157 
1158         /* Handle umasking inside the fuse code */
1159         if (sb->s_flags & SB_POSIXACL)
1160                 fc->dont_mask = 1;
1161         sb->s_flags |= SB_POSIXACL;
1162 
1163         fc->default_permissions = d.default_permissions;
1164         fc->allow_other = d.allow_other;
1165         fc->user_id = d.user_id;
1166         fc->group_id = d.group_id;
1167         fc->max_read = max_t(unsigned, 4096, d.max_read);
1168 
1169         /* Used by get_root_inode() */
1170         sb->s_fs_info = fc;
1171 
1172         err = -ENOMEM;
1173         root = fuse_get_root_inode(sb, d.rootmode);
1174         sb->s_d_op = &fuse_root_dentry_operations;
1175         root_dentry = d_make_root(root);
1176         if (!root_dentry)
1177                 goto err_dev_free;
1178         /* Root dentry doesn't have .d_revalidate */
1179         sb->s_d_op = &fuse_dentry_operations;
1180 
1181         init_req = fuse_request_alloc(0);
1182         if (!init_req)
1183                 goto err_put_root;
1184         __set_bit(FR_BACKGROUND, &init_req->flags);
1185 
1186         if (is_bdev) {
1187                 fc->destroy_req = fuse_request_alloc(0);
1188                 if (!fc->destroy_req)
1189                         goto err_free_init_req;
1190         }
1191 
1192         mutex_lock(&fuse_mutex);
1193         err = -EINVAL;
1194         if (file->private_data)
1195                 goto err_unlock;
1196 
1197         err = fuse_ctl_add_conn(fc);
1198         if (err)
1199                 goto err_unlock;
1200 
1201         list_add_tail(&fc->entry, &fuse_conn_list);
1202         sb->s_root = root_dentry;
1203         file->private_data = fud;
1204         mutex_unlock(&fuse_mutex);
1205         /*
1206          * atomic_dec_and_test() in fput() provides the necessary
1207          * memory barrier for file->private_data to be visible on all
1208          * CPUs after this
1209          */
1210         fput(file);
1211 
1212         fuse_send_init(fc, init_req);
1213 
1214         return 0;
1215 
1216  err_unlock:
1217         mutex_unlock(&fuse_mutex);
1218  err_free_init_req:
1219         fuse_request_free(init_req);
1220  err_put_root:
1221         dput(root_dentry);
1222  err_dev_free:
1223         fuse_dev_free(fud);
1224  err_put_conn:
1225         fuse_conn_put(fc);
1226         sb->s_fs_info = NULL;
1227  err_fput:
1228         fput(file);
1229  err:
1230         return err;
1231 }
1232 
1233 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1234                        int flags, const char *dev_name,
1235                        void *raw_data)
1236 {
1237         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1238 }
1239 
1240 static void fuse_sb_destroy(struct super_block *sb)
1241 {
1242         struct fuse_conn *fc = get_fuse_conn_super(sb);
1243 
1244         if (fc) {
1245                 fuse_send_destroy(fc);
1246 
1247                 fuse_abort_conn(fc);
1248                 fuse_wait_aborted(fc);
1249 
1250                 down_write(&fc->killsb);
1251                 fc->sb = NULL;
1252                 up_write(&fc->killsb);
1253         }
1254 }
1255 
1256 static void fuse_kill_sb_anon(struct super_block *sb)
1257 {
1258         fuse_sb_destroy(sb);
1259         kill_anon_super(sb);
1260 }
1261 
1262 static struct file_system_type fuse_fs_type = {
1263         .owner          = THIS_MODULE,
1264         .name           = "fuse",
1265         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1266         .mount          = fuse_mount,
1267         .kill_sb        = fuse_kill_sb_anon,
1268 };
1269 MODULE_ALIAS_FS("fuse");
1270 
1271 #ifdef CONFIG_BLOCK
1272 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1273                            int flags, const char *dev_name,
1274                            void *raw_data)
1275 {
1276         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1277 }
1278 
1279 static void fuse_kill_sb_blk(struct super_block *sb)
1280 {
1281         fuse_sb_destroy(sb);
1282         kill_block_super(sb);
1283 }
1284 
1285 static struct file_system_type fuseblk_fs_type = {
1286         .owner          = THIS_MODULE,
1287         .name           = "fuseblk",
1288         .mount          = fuse_mount_blk,
1289         .kill_sb        = fuse_kill_sb_blk,
1290         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1291 };
1292 MODULE_ALIAS_FS("fuseblk");
1293 
1294 static inline int register_fuseblk(void)
1295 {
1296         return register_filesystem(&fuseblk_fs_type);
1297 }
1298 
1299 static inline void unregister_fuseblk(void)
1300 {
1301         unregister_filesystem(&fuseblk_fs_type);
1302 }
1303 #else
1304 static inline int register_fuseblk(void)
1305 {
1306         return 0;
1307 }
1308 
1309 static inline void unregister_fuseblk(void)
1310 {
1311 }
1312 #endif
1313 
1314 static void fuse_inode_init_once(void *foo)
1315 {
1316         struct inode *inode = foo;
1317 
1318         inode_init_once(inode);
1319 }
1320 
1321 static int __init fuse_fs_init(void)
1322 {
1323         int err;
1324 
1325         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1326                         sizeof(struct fuse_inode), 0,
1327                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1328                         fuse_inode_init_once);
1329         err = -ENOMEM;
1330         if (!fuse_inode_cachep)
1331                 goto out;
1332 
1333         err = register_fuseblk();
1334         if (err)
1335                 goto out2;
1336 
1337         err = register_filesystem(&fuse_fs_type);
1338         if (err)
1339                 goto out3;
1340 
1341         return 0;
1342 
1343  out3:
1344         unregister_fuseblk();
1345  out2:
1346         kmem_cache_destroy(fuse_inode_cachep);
1347  out:
1348         return err;
1349 }
1350 
1351 static void fuse_fs_cleanup(void)
1352 {
1353         unregister_filesystem(&fuse_fs_type);
1354         unregister_fuseblk();
1355 
1356         /*
1357          * Make sure all delayed rcu free inodes are flushed before we
1358          * destroy cache.
1359          */
1360         rcu_barrier();
1361         kmem_cache_destroy(fuse_inode_cachep);
1362 }
1363 
1364 static struct kobject *fuse_kobj;
1365 
1366 static int fuse_sysfs_init(void)
1367 {
1368         int err;
1369 
1370         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1371         if (!fuse_kobj) {
1372                 err = -ENOMEM;
1373                 goto out_err;
1374         }
1375 
1376         err = sysfs_create_mount_point(fuse_kobj, "connections");
1377         if (err)
1378                 goto out_fuse_unregister;
1379 
1380         return 0;
1381 
1382  out_fuse_unregister:
1383         kobject_put(fuse_kobj);
1384  out_err:
1385         return err;
1386 }
1387 
1388 static void fuse_sysfs_cleanup(void)
1389 {
1390         sysfs_remove_mount_point(fuse_kobj, "connections");
1391         kobject_put(fuse_kobj);
1392 }
1393 
1394 static int __init fuse_init(void)
1395 {
1396         int res;
1397 
1398         pr_info("init (API version %i.%i)\n",
1399                 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1400 
1401         INIT_LIST_HEAD(&fuse_conn_list);
1402         res = fuse_fs_init();
1403         if (res)
1404                 goto err;
1405 
1406         res = fuse_dev_init();
1407         if (res)
1408                 goto err_fs_cleanup;
1409 
1410         res = fuse_sysfs_init();
1411         if (res)
1412                 goto err_dev_cleanup;
1413 
1414         res = fuse_ctl_init();
1415         if (res)
1416                 goto err_sysfs_cleanup;
1417 
1418         sanitize_global_limit(&max_user_bgreq);
1419         sanitize_global_limit(&max_user_congthresh);
1420 
1421         return 0;
1422 
1423  err_sysfs_cleanup:
1424         fuse_sysfs_cleanup();
1425  err_dev_cleanup:
1426         fuse_dev_cleanup();
1427  err_fs_cleanup:
1428         fuse_fs_cleanup();
1429  err:
1430         return res;
1431 }
1432 
1433 static void __exit fuse_exit(void)
1434 {
1435         pr_debug("exit\n");
1436 
1437         fuse_ctl_cleanup();
1438         fuse_sysfs_cleanup();
1439         fuse_fs_cleanup();
1440         fuse_dev_cleanup();
1441 }
1442 
1443 module_init(fuse_init);
1444 module_exit(fuse_exit);
1445 

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