9c761b611c5418b1fcc8b08d7b144a3a1689cdf0
[sfrench/cifs-2.6.git] / fs / fuse / inode.c
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
24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
25 MODULE_DESCRIPTION("Filesystem in Userspace");
26 MODULE_LICENSE("GPL");
27
28 static struct kmem_cache *fuse_inode_cachep;
29 struct list_head fuse_conn_list;
30 DEFINE_MUTEX(fuse_mutex);
31
32 static int set_global_limit(const char *val, struct kernel_param *kp);
33
34 unsigned max_user_bgreq;
35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
36                   &max_user_bgreq, 0644);
37 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
38 MODULE_PARM_DESC(max_user_bgreq,
39  "Global limit for the maximum number of backgrounded requests an "
40  "unprivileged user can set");
41
42 unsigned max_user_congthresh;
43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
44                   &max_user_congthresh, 0644);
45 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
46 MODULE_PARM_DESC(max_user_congthresh,
47  "Global limit for the maximum congestion threshold an "
48  "unprivileged user can set");
49
50 #define FUSE_SUPER_MAGIC 0x65735546
51
52 #define FUSE_DEFAULT_BLKSIZE 512
53
54 /** Maximum number of outstanding background requests */
55 #define FUSE_DEFAULT_MAX_BACKGROUND 12
56
57 /** Congestion starts at 75% of maximum */
58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
59
60 struct fuse_mount_data {
61         int fd;
62         unsigned rootmode;
63         kuid_t user_id;
64         kgid_t group_id;
65         unsigned fd_present:1;
66         unsigned rootmode_present:1;
67         unsigned user_id_present:1;
68         unsigned group_id_present:1;
69         unsigned flags;
70         unsigned max_read;
71         unsigned blksize;
72 };
73
74 struct fuse_forget_link *fuse_alloc_forget(void)
75 {
76         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
77 }
78
79 static struct inode *fuse_alloc_inode(struct super_block *sb)
80 {
81         struct inode *inode;
82         struct fuse_inode *fi;
83
84         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
85         if (!inode)
86                 return NULL;
87
88         fi = get_fuse_inode(inode);
89         fi->i_time = 0;
90         fi->nodeid = 0;
91         fi->nlookup = 0;
92         fi->attr_version = 0;
93         fi->writectr = 0;
94         fi->orig_ino = 0;
95         fi->state = 0;
96         INIT_LIST_HEAD(&fi->write_files);
97         INIT_LIST_HEAD(&fi->queued_writes);
98         INIT_LIST_HEAD(&fi->writepages);
99         init_waitqueue_head(&fi->page_waitq);
100         fi->forget = fuse_alloc_forget();
101         if (!fi->forget) {
102                 kmem_cache_free(fuse_inode_cachep, inode);
103                 return NULL;
104         }
105
106         return inode;
107 }
108
109 static void fuse_i_callback(struct rcu_head *head)
110 {
111         struct inode *inode = container_of(head, struct inode, i_rcu);
112         kmem_cache_free(fuse_inode_cachep, inode);
113 }
114
115 static void fuse_destroy_inode(struct inode *inode)
116 {
117         struct fuse_inode *fi = get_fuse_inode(inode);
118         BUG_ON(!list_empty(&fi->write_files));
119         BUG_ON(!list_empty(&fi->queued_writes));
120         kfree(fi->forget);
121         call_rcu(&inode->i_rcu, fuse_i_callback);
122 }
123
124 static void fuse_evict_inode(struct inode *inode)
125 {
126         truncate_inode_pages_final(&inode->i_data);
127         clear_inode(inode);
128         if (inode->i_sb->s_flags & MS_ACTIVE) {
129                 struct fuse_conn *fc = get_fuse_conn(inode);
130                 struct fuse_inode *fi = get_fuse_inode(inode);
131                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
132                 fi->forget = NULL;
133         }
134 }
135
136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
137 {
138         if (*flags & MS_MANDLOCK)
139                 return -EINVAL;
140
141         return 0;
142 }
143
144 /*
145  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
146  * so that it will fit.
147  */
148 static ino_t fuse_squash_ino(u64 ino64)
149 {
150         ino_t ino = (ino_t) ino64;
151         if (sizeof(ino_t) < sizeof(u64))
152                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
153         return ino;
154 }
155
156 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
157                                    u64 attr_valid)
158 {
159         struct fuse_conn *fc = get_fuse_conn(inode);
160         struct fuse_inode *fi = get_fuse_inode(inode);
161
162         fi->attr_version = ++fc->attr_version;
163         fi->i_time = attr_valid;
164
165         inode->i_ino     = fuse_squash_ino(attr->ino);
166         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
167         set_nlink(inode, attr->nlink);
168         inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
169         inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
170         inode->i_blocks  = attr->blocks;
171         inode->i_atime.tv_sec   = attr->atime;
172         inode->i_atime.tv_nsec  = attr->atimensec;
173         inode->i_mtime.tv_sec   = attr->mtime;
174         inode->i_mtime.tv_nsec  = attr->mtimensec;
175         inode->i_ctime.tv_sec   = attr->ctime;
176         inode->i_ctime.tv_nsec  = attr->ctimensec;
177
178         if (attr->blksize != 0)
179                 inode->i_blkbits = ilog2(attr->blksize);
180         else
181                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
182
183         /*
184          * Don't set the sticky bit in i_mode, unless we want the VFS
185          * to check permissions.  This prevents failures due to the
186          * check in may_delete().
187          */
188         fi->orig_i_mode = inode->i_mode;
189         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
190                 inode->i_mode &= ~S_ISVTX;
191
192         fi->orig_ino = attr->ino;
193 }
194
195 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
196                             u64 attr_valid, u64 attr_version)
197 {
198         struct fuse_conn *fc = get_fuse_conn(inode);
199         struct fuse_inode *fi = get_fuse_inode(inode);
200         loff_t oldsize;
201         struct timespec old_mtime;
202
203         spin_lock(&fc->lock);
204         if ((attr_version != 0 && fi->attr_version > attr_version) ||
205             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
206                 spin_unlock(&fc->lock);
207                 return;
208         }
209
210         old_mtime = inode->i_mtime;
211         fuse_change_attributes_common(inode, attr, attr_valid);
212
213         oldsize = inode->i_size;
214         i_size_write(inode, attr->size);
215         spin_unlock(&fc->lock);
216
217         if (S_ISREG(inode->i_mode)) {
218                 bool inval = false;
219
220                 if (oldsize != attr->size) {
221                         truncate_pagecache(inode, attr->size);
222                         inval = true;
223                 } else if (fc->auto_inval_data) {
224                         struct timespec new_mtime = {
225                                 .tv_sec = attr->mtime,
226                                 .tv_nsec = attr->mtimensec,
227                         };
228
229                         /*
230                          * Auto inval mode also checks and invalidates if mtime
231                          * has changed.
232                          */
233                         if (!timespec_equal(&old_mtime, &new_mtime))
234                                 inval = true;
235                 }
236
237                 if (inval)
238                         invalidate_inode_pages2(inode->i_mapping);
239         }
240 }
241
242 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
243 {
244         inode->i_mode = attr->mode & S_IFMT;
245         inode->i_size = attr->size;
246         if (S_ISREG(inode->i_mode)) {
247                 fuse_init_common(inode);
248                 fuse_init_file_inode(inode);
249         } else if (S_ISDIR(inode->i_mode))
250                 fuse_init_dir(inode);
251         else if (S_ISLNK(inode->i_mode))
252                 fuse_init_symlink(inode);
253         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
254                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
255                 fuse_init_common(inode);
256                 init_special_inode(inode, inode->i_mode,
257                                    new_decode_dev(attr->rdev));
258         } else
259                 BUG();
260 }
261
262 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
263 {
264         u64 nodeid = *(u64 *) _nodeidp;
265         if (get_node_id(inode) == nodeid)
266                 return 1;
267         else
268                 return 0;
269 }
270
271 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
272 {
273         u64 nodeid = *(u64 *) _nodeidp;
274         get_fuse_inode(inode)->nodeid = nodeid;
275         return 0;
276 }
277
278 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
279                         int generation, struct fuse_attr *attr,
280                         u64 attr_valid, u64 attr_version)
281 {
282         struct inode *inode;
283         struct fuse_inode *fi;
284         struct fuse_conn *fc = get_fuse_conn_super(sb);
285
286  retry:
287         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
288         if (!inode)
289                 return NULL;
290
291         if ((inode->i_state & I_NEW)) {
292                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
293                 inode->i_generation = generation;
294                 inode->i_data.backing_dev_info = &fc->bdi;
295                 fuse_init_inode(inode, attr);
296                 unlock_new_inode(inode);
297         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
298                 /* Inode has changed type, any I/O on the old should fail */
299                 make_bad_inode(inode);
300                 iput(inode);
301                 goto retry;
302         }
303
304         fi = get_fuse_inode(inode);
305         spin_lock(&fc->lock);
306         fi->nlookup++;
307         spin_unlock(&fc->lock);
308         fuse_change_attributes(inode, attr, attr_valid, attr_version);
309
310         return inode;
311 }
312
313 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
314                              loff_t offset, loff_t len)
315 {
316         struct inode *inode;
317         pgoff_t pg_start;
318         pgoff_t pg_end;
319
320         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
321         if (!inode)
322                 return -ENOENT;
323
324         fuse_invalidate_attr(inode);
325         if (offset >= 0) {
326                 pg_start = offset >> PAGE_CACHE_SHIFT;
327                 if (len <= 0)
328                         pg_end = -1;
329                 else
330                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
331                 invalidate_inode_pages2_range(inode->i_mapping,
332                                               pg_start, pg_end);
333         }
334         iput(inode);
335         return 0;
336 }
337
338 static void fuse_umount_begin(struct super_block *sb)
339 {
340         fuse_abort_conn(get_fuse_conn_super(sb));
341 }
342
343 static void fuse_send_destroy(struct fuse_conn *fc)
344 {
345         struct fuse_req *req = fc->destroy_req;
346         if (req && fc->conn_init) {
347                 fc->destroy_req = NULL;
348                 req->in.h.opcode = FUSE_DESTROY;
349                 req->force = 1;
350                 req->background = 0;
351                 fuse_request_send(fc, req);
352                 fuse_put_request(fc, req);
353         }
354 }
355
356 static void fuse_bdi_destroy(struct fuse_conn *fc)
357 {
358         if (fc->bdi_initialized)
359                 bdi_destroy(&fc->bdi);
360 }
361
362 void fuse_conn_kill(struct fuse_conn *fc)
363 {
364         spin_lock(&fc->lock);
365         fc->connected = 0;
366         fc->blocked = 0;
367         fc->initialized = 1;
368         spin_unlock(&fc->lock);
369         /* Flush all readers on this fs */
370         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
371         wake_up_all(&fc->waitq);
372         wake_up_all(&fc->blocked_waitq);
373         wake_up_all(&fc->reserved_req_waitq);
374 }
375 EXPORT_SYMBOL_GPL(fuse_conn_kill);
376
377 static void fuse_put_super(struct super_block *sb)
378 {
379         struct fuse_conn *fc = get_fuse_conn_super(sb);
380
381         fuse_send_destroy(fc);
382
383         fuse_conn_kill(fc);
384         mutex_lock(&fuse_mutex);
385         list_del(&fc->entry);
386         fuse_ctl_remove_conn(fc);
387         mutex_unlock(&fuse_mutex);
388         fuse_bdi_destroy(fc);
389
390         fuse_conn_put(fc);
391 }
392
393 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
394 {
395         stbuf->f_type    = FUSE_SUPER_MAGIC;
396         stbuf->f_bsize   = attr->bsize;
397         stbuf->f_frsize  = attr->frsize;
398         stbuf->f_blocks  = attr->blocks;
399         stbuf->f_bfree   = attr->bfree;
400         stbuf->f_bavail  = attr->bavail;
401         stbuf->f_files   = attr->files;
402         stbuf->f_ffree   = attr->ffree;
403         stbuf->f_namelen = attr->namelen;
404         /* fsid is left zero */
405 }
406
407 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
408 {
409         struct super_block *sb = dentry->d_sb;
410         struct fuse_conn *fc = get_fuse_conn_super(sb);
411         struct fuse_req *req;
412         struct fuse_statfs_out outarg;
413         int err;
414
415         if (!fuse_allow_current_process(fc)) {
416                 buf->f_type = FUSE_SUPER_MAGIC;
417                 return 0;
418         }
419
420         req = fuse_get_req_nopages(fc);
421         if (IS_ERR(req))
422                 return PTR_ERR(req);
423
424         memset(&outarg, 0, sizeof(outarg));
425         req->in.numargs = 0;
426         req->in.h.opcode = FUSE_STATFS;
427         req->in.h.nodeid = get_node_id(dentry->d_inode);
428         req->out.numargs = 1;
429         req->out.args[0].size =
430                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
431         req->out.args[0].value = &outarg;
432         fuse_request_send(fc, req);
433         err = req->out.h.error;
434         if (!err)
435                 convert_fuse_statfs(buf, &outarg.st);
436         fuse_put_request(fc, req);
437         return err;
438 }
439
440 enum {
441         OPT_FD,
442         OPT_ROOTMODE,
443         OPT_USER_ID,
444         OPT_GROUP_ID,
445         OPT_DEFAULT_PERMISSIONS,
446         OPT_ALLOW_OTHER,
447         OPT_MAX_READ,
448         OPT_BLKSIZE,
449         OPT_ERR
450 };
451
452 static const match_table_t tokens = {
453         {OPT_FD,                        "fd=%u"},
454         {OPT_ROOTMODE,                  "rootmode=%o"},
455         {OPT_USER_ID,                   "user_id=%u"},
456         {OPT_GROUP_ID,                  "group_id=%u"},
457         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
458         {OPT_ALLOW_OTHER,               "allow_other"},
459         {OPT_MAX_READ,                  "max_read=%u"},
460         {OPT_BLKSIZE,                   "blksize=%u"},
461         {OPT_ERR,                       NULL}
462 };
463
464 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
465 {
466         char *p;
467         memset(d, 0, sizeof(struct fuse_mount_data));
468         d->max_read = ~0;
469         d->blksize = FUSE_DEFAULT_BLKSIZE;
470
471         while ((p = strsep(&opt, ",")) != NULL) {
472                 int token;
473                 int value;
474                 substring_t args[MAX_OPT_ARGS];
475                 if (!*p)
476                         continue;
477
478                 token = match_token(p, tokens, args);
479                 switch (token) {
480                 case OPT_FD:
481                         if (match_int(&args[0], &value))
482                                 return 0;
483                         d->fd = value;
484                         d->fd_present = 1;
485                         break;
486
487                 case OPT_ROOTMODE:
488                         if (match_octal(&args[0], &value))
489                                 return 0;
490                         if (!fuse_valid_type(value))
491                                 return 0;
492                         d->rootmode = value;
493                         d->rootmode_present = 1;
494                         break;
495
496                 case OPT_USER_ID:
497                         if (match_int(&args[0], &value))
498                                 return 0;
499                         d->user_id = make_kuid(current_user_ns(), value);
500                         if (!uid_valid(d->user_id))
501                                 return 0;
502                         d->user_id_present = 1;
503                         break;
504
505                 case OPT_GROUP_ID:
506                         if (match_int(&args[0], &value))
507                                 return 0;
508                         d->group_id = make_kgid(current_user_ns(), value);
509                         if (!gid_valid(d->group_id))
510                                 return 0;
511                         d->group_id_present = 1;
512                         break;
513
514                 case OPT_DEFAULT_PERMISSIONS:
515                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
516                         break;
517
518                 case OPT_ALLOW_OTHER:
519                         d->flags |= FUSE_ALLOW_OTHER;
520                         break;
521
522                 case OPT_MAX_READ:
523                         if (match_int(&args[0], &value))
524                                 return 0;
525                         d->max_read = value;
526                         break;
527
528                 case OPT_BLKSIZE:
529                         if (!is_bdev || match_int(&args[0], &value))
530                                 return 0;
531                         d->blksize = value;
532                         break;
533
534                 default:
535                         return 0;
536                 }
537         }
538
539         if (!d->fd_present || !d->rootmode_present ||
540             !d->user_id_present || !d->group_id_present)
541                 return 0;
542
543         return 1;
544 }
545
546 static int fuse_show_options(struct seq_file *m, struct dentry *root)
547 {
548         struct super_block *sb = root->d_sb;
549         struct fuse_conn *fc = get_fuse_conn_super(sb);
550
551         seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
552         seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
553         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
554                 seq_puts(m, ",default_permissions");
555         if (fc->flags & FUSE_ALLOW_OTHER)
556                 seq_puts(m, ",allow_other");
557         if (fc->max_read != ~0)
558                 seq_printf(m, ",max_read=%u", fc->max_read);
559         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
560                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
561         return 0;
562 }
563
564 void fuse_conn_init(struct fuse_conn *fc)
565 {
566         memset(fc, 0, sizeof(*fc));
567         spin_lock_init(&fc->lock);
568         init_rwsem(&fc->killsb);
569         atomic_set(&fc->count, 1);
570         init_waitqueue_head(&fc->waitq);
571         init_waitqueue_head(&fc->blocked_waitq);
572         init_waitqueue_head(&fc->reserved_req_waitq);
573         INIT_LIST_HEAD(&fc->pending);
574         INIT_LIST_HEAD(&fc->processing);
575         INIT_LIST_HEAD(&fc->io);
576         INIT_LIST_HEAD(&fc->interrupts);
577         INIT_LIST_HEAD(&fc->bg_queue);
578         INIT_LIST_HEAD(&fc->entry);
579         fc->forget_list_tail = &fc->forget_list_head;
580         atomic_set(&fc->num_waiting, 0);
581         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
582         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
583         fc->khctr = 0;
584         fc->polled_files = RB_ROOT;
585         fc->reqctr = 0;
586         fc->blocked = 0;
587         fc->initialized = 0;
588         fc->attr_version = 1;
589         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
590 }
591 EXPORT_SYMBOL_GPL(fuse_conn_init);
592
593 void fuse_conn_put(struct fuse_conn *fc)
594 {
595         if (atomic_dec_and_test(&fc->count)) {
596                 if (fc->destroy_req)
597                         fuse_request_free(fc->destroy_req);
598                 fc->release(fc);
599         }
600 }
601 EXPORT_SYMBOL_GPL(fuse_conn_put);
602
603 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
604 {
605         atomic_inc(&fc->count);
606         return fc;
607 }
608 EXPORT_SYMBOL_GPL(fuse_conn_get);
609
610 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
611 {
612         struct fuse_attr attr;
613         memset(&attr, 0, sizeof(attr));
614
615         attr.mode = mode;
616         attr.ino = FUSE_ROOT_ID;
617         attr.nlink = 1;
618         return fuse_iget(sb, 1, 0, &attr, 0, 0);
619 }
620
621 struct fuse_inode_handle {
622         u64 nodeid;
623         u32 generation;
624 };
625
626 static struct dentry *fuse_get_dentry(struct super_block *sb,
627                                       struct fuse_inode_handle *handle)
628 {
629         struct fuse_conn *fc = get_fuse_conn_super(sb);
630         struct inode *inode;
631         struct dentry *entry;
632         int err = -ESTALE;
633
634         if (handle->nodeid == 0)
635                 goto out_err;
636
637         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
638         if (!inode) {
639                 struct fuse_entry_out outarg;
640                 struct qstr name;
641
642                 if (!fc->export_support)
643                         goto out_err;
644
645                 name.len = 1;
646                 name.name = ".";
647                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
648                                        &inode);
649                 if (err && err != -ENOENT)
650                         goto out_err;
651                 if (err || !inode) {
652                         err = -ESTALE;
653                         goto out_err;
654                 }
655                 err = -EIO;
656                 if (get_node_id(inode) != handle->nodeid)
657                         goto out_iput;
658         }
659         err = -ESTALE;
660         if (inode->i_generation != handle->generation)
661                 goto out_iput;
662
663         entry = d_obtain_alias(inode);
664         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
665                 fuse_invalidate_entry_cache(entry);
666
667         return entry;
668
669  out_iput:
670         iput(inode);
671  out_err:
672         return ERR_PTR(err);
673 }
674
675 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
676                            struct inode *parent)
677 {
678         int len = parent ? 6 : 3;
679         u64 nodeid;
680         u32 generation;
681
682         if (*max_len < len) {
683                 *max_len = len;
684                 return  FILEID_INVALID;
685         }
686
687         nodeid = get_fuse_inode(inode)->nodeid;
688         generation = inode->i_generation;
689
690         fh[0] = (u32)(nodeid >> 32);
691         fh[1] = (u32)(nodeid & 0xffffffff);
692         fh[2] = generation;
693
694         if (parent) {
695                 nodeid = get_fuse_inode(parent)->nodeid;
696                 generation = parent->i_generation;
697
698                 fh[3] = (u32)(nodeid >> 32);
699                 fh[4] = (u32)(nodeid & 0xffffffff);
700                 fh[5] = generation;
701         }
702
703         *max_len = len;
704         return parent ? 0x82 : 0x81;
705 }
706
707 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
708                 struct fid *fid, int fh_len, int fh_type)
709 {
710         struct fuse_inode_handle handle;
711
712         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
713                 return NULL;
714
715         handle.nodeid = (u64) fid->raw[0] << 32;
716         handle.nodeid |= (u64) fid->raw[1];
717         handle.generation = fid->raw[2];
718         return fuse_get_dentry(sb, &handle);
719 }
720
721 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
722                 struct fid *fid, int fh_len, int fh_type)
723 {
724         struct fuse_inode_handle parent;
725
726         if (fh_type != 0x82 || fh_len < 6)
727                 return NULL;
728
729         parent.nodeid = (u64) fid->raw[3] << 32;
730         parent.nodeid |= (u64) fid->raw[4];
731         parent.generation = fid->raw[5];
732         return fuse_get_dentry(sb, &parent);
733 }
734
735 static struct dentry *fuse_get_parent(struct dentry *child)
736 {
737         struct inode *child_inode = child->d_inode;
738         struct fuse_conn *fc = get_fuse_conn(child_inode);
739         struct inode *inode;
740         struct dentry *parent;
741         struct fuse_entry_out outarg;
742         struct qstr name;
743         int err;
744
745         if (!fc->export_support)
746                 return ERR_PTR(-ESTALE);
747
748         name.len = 2;
749         name.name = "..";
750         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
751                                &name, &outarg, &inode);
752         if (err) {
753                 if (err == -ENOENT)
754                         return ERR_PTR(-ESTALE);
755                 return ERR_PTR(err);
756         }
757
758         parent = d_obtain_alias(inode);
759         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
760                 fuse_invalidate_entry_cache(parent);
761
762         return parent;
763 }
764
765 static const struct export_operations fuse_export_operations = {
766         .fh_to_dentry   = fuse_fh_to_dentry,
767         .fh_to_parent   = fuse_fh_to_parent,
768         .encode_fh      = fuse_encode_fh,
769         .get_parent     = fuse_get_parent,
770 };
771
772 static const struct super_operations fuse_super_operations = {
773         .alloc_inode    = fuse_alloc_inode,
774         .destroy_inode  = fuse_destroy_inode,
775         .evict_inode    = fuse_evict_inode,
776         .drop_inode     = generic_delete_inode,
777         .remount_fs     = fuse_remount_fs,
778         .put_super      = fuse_put_super,
779         .umount_begin   = fuse_umount_begin,
780         .statfs         = fuse_statfs,
781         .show_options   = fuse_show_options,
782 };
783
784 static void sanitize_global_limit(unsigned *limit)
785 {
786         if (*limit == 0)
787                 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
788                          sizeof(struct fuse_req);
789
790         if (*limit >= 1 << 16)
791                 *limit = (1 << 16) - 1;
792 }
793
794 static int set_global_limit(const char *val, struct kernel_param *kp)
795 {
796         int rv;
797
798         rv = param_set_uint(val, kp);
799         if (rv)
800                 return rv;
801
802         sanitize_global_limit((unsigned *)kp->arg);
803
804         return 0;
805 }
806
807 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
808 {
809         int cap_sys_admin = capable(CAP_SYS_ADMIN);
810
811         if (arg->minor < 13)
812                 return;
813
814         sanitize_global_limit(&max_user_bgreq);
815         sanitize_global_limit(&max_user_congthresh);
816
817         if (arg->max_background) {
818                 fc->max_background = arg->max_background;
819
820                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
821                         fc->max_background = max_user_bgreq;
822         }
823         if (arg->congestion_threshold) {
824                 fc->congestion_threshold = arg->congestion_threshold;
825
826                 if (!cap_sys_admin &&
827                     fc->congestion_threshold > max_user_congthresh)
828                         fc->congestion_threshold = max_user_congthresh;
829         }
830 }
831
832 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
833 {
834         struct fuse_init_out *arg = &req->misc.init_out;
835
836         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
837                 fc->conn_error = 1;
838         else {
839                 unsigned long ra_pages;
840
841                 process_init_limits(fc, arg);
842
843                 if (arg->minor >= 6) {
844                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
845                         if (arg->flags & FUSE_ASYNC_READ)
846                                 fc->async_read = 1;
847                         if (!(arg->flags & FUSE_POSIX_LOCKS))
848                                 fc->no_lock = 1;
849                         if (arg->minor >= 17) {
850                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
851                                         fc->no_flock = 1;
852                         } else {
853                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
854                                         fc->no_flock = 1;
855                         }
856                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
857                                 fc->atomic_o_trunc = 1;
858                         if (arg->minor >= 9) {
859                                 /* LOOKUP has dependency on proto version */
860                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
861                                         fc->export_support = 1;
862                         }
863                         if (arg->flags & FUSE_BIG_WRITES)
864                                 fc->big_writes = 1;
865                         if (arg->flags & FUSE_DONT_MASK)
866                                 fc->dont_mask = 1;
867                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
868                                 fc->auto_inval_data = 1;
869                         if (arg->flags & FUSE_DO_READDIRPLUS) {
870                                 fc->do_readdirplus = 1;
871                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
872                                         fc->readdirplus_auto = 1;
873                         }
874                         if (arg->flags & FUSE_ASYNC_DIO)
875                                 fc->async_dio = 1;
876                 } else {
877                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
878                         fc->no_lock = 1;
879                         fc->no_flock = 1;
880                 }
881
882                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
883                 fc->minor = arg->minor;
884                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
885                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
886                 fc->conn_init = 1;
887         }
888         fc->initialized = 1;
889         wake_up_all(&fc->blocked_waitq);
890 }
891
892 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
893 {
894         struct fuse_init_in *arg = &req->misc.init_in;
895
896         arg->major = FUSE_KERNEL_VERSION;
897         arg->minor = FUSE_KERNEL_MINOR_VERSION;
898         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
899         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
900                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
901                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
902                 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
903                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
904         req->in.h.opcode = FUSE_INIT;
905         req->in.numargs = 1;
906         req->in.args[0].size = sizeof(*arg);
907         req->in.args[0].value = arg;
908         req->out.numargs = 1;
909         /* Variable length argument used for backward compatibility
910            with interface version < 7.5.  Rest of init_out is zeroed
911            by do_get_request(), so a short reply is not a problem */
912         req->out.argvar = 1;
913         req->out.args[0].size = sizeof(struct fuse_init_out);
914         req->out.args[0].value = &req->misc.init_out;
915         req->end = process_init_reply;
916         fuse_request_send_background(fc, req);
917 }
918
919 static void fuse_free_conn(struct fuse_conn *fc)
920 {
921         kfree_rcu(fc, rcu);
922 }
923
924 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
925 {
926         int err;
927
928         fc->bdi.name = "fuse";
929         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
930         /* fuse does it's own writeback accounting */
931         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
932
933         err = bdi_init(&fc->bdi);
934         if (err)
935                 return err;
936
937         fc->bdi_initialized = 1;
938
939         if (sb->s_bdev) {
940                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
941                                     MAJOR(fc->dev), MINOR(fc->dev));
942         } else {
943                 err = bdi_register_dev(&fc->bdi, fc->dev);
944         }
945
946         if (err)
947                 return err;
948
949         /*
950          * For a single fuse filesystem use max 1% of dirty +
951          * writeback threshold.
952          *
953          * This gives about 1M of write buffer for memory maps on a
954          * machine with 1G and 10% dirty_ratio, which should be more
955          * than enough.
956          *
957          * Privileged users can raise it by writing to
958          *
959          *    /sys/class/bdi/<bdi>/max_ratio
960          */
961         bdi_set_max_ratio(&fc->bdi, 1);
962
963         return 0;
964 }
965
966 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
967 {
968         struct fuse_conn *fc;
969         struct inode *root;
970         struct fuse_mount_data d;
971         struct file *file;
972         struct dentry *root_dentry;
973         struct fuse_req *init_req;
974         int err;
975         int is_bdev = sb->s_bdev != NULL;
976
977         err = -EINVAL;
978         if (sb->s_flags & MS_MANDLOCK)
979                 goto err;
980
981         sb->s_flags &= ~MS_NOSEC;
982
983         if (!parse_fuse_opt((char *) data, &d, is_bdev))
984                 goto err;
985
986         if (is_bdev) {
987 #ifdef CONFIG_BLOCK
988                 err = -EINVAL;
989                 if (!sb_set_blocksize(sb, d.blksize))
990                         goto err;
991 #endif
992         } else {
993                 sb->s_blocksize = PAGE_CACHE_SIZE;
994                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
995         }
996         sb->s_magic = FUSE_SUPER_MAGIC;
997         sb->s_op = &fuse_super_operations;
998         sb->s_maxbytes = MAX_LFS_FILESIZE;
999         sb->s_time_gran = 1;
1000         sb->s_export_op = &fuse_export_operations;
1001
1002         file = fget(d.fd);
1003         err = -EINVAL;
1004         if (!file)
1005                 goto err;
1006
1007         if ((file->f_op != &fuse_dev_operations) ||
1008             (file->f_cred->user_ns != &init_user_ns))
1009                 goto err_fput;
1010
1011         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1012         err = -ENOMEM;
1013         if (!fc)
1014                 goto err_fput;
1015
1016         fuse_conn_init(fc);
1017
1018         fc->dev = sb->s_dev;
1019         fc->sb = sb;
1020         err = fuse_bdi_init(fc, sb);
1021         if (err)
1022                 goto err_put_conn;
1023
1024         sb->s_bdi = &fc->bdi;
1025
1026         /* Handle umasking inside the fuse code */
1027         if (sb->s_flags & MS_POSIXACL)
1028                 fc->dont_mask = 1;
1029         sb->s_flags |= MS_POSIXACL;
1030
1031         fc->release = fuse_free_conn;
1032         fc->flags = d.flags;
1033         fc->user_id = d.user_id;
1034         fc->group_id = d.group_id;
1035         fc->max_read = max_t(unsigned, 4096, d.max_read);
1036
1037         /* Used by get_root_inode() */
1038         sb->s_fs_info = fc;
1039
1040         err = -ENOMEM;
1041         root = fuse_get_root_inode(sb, d.rootmode);
1042         root_dentry = d_make_root(root);
1043         if (!root_dentry)
1044                 goto err_put_conn;
1045         /* only now - we want root dentry with NULL ->d_op */
1046         sb->s_d_op = &fuse_dentry_operations;
1047
1048         init_req = fuse_request_alloc(0);
1049         if (!init_req)
1050                 goto err_put_root;
1051         init_req->background = 1;
1052
1053         if (is_bdev) {
1054                 fc->destroy_req = fuse_request_alloc(0);
1055                 if (!fc->destroy_req)
1056                         goto err_free_init_req;
1057         }
1058
1059         mutex_lock(&fuse_mutex);
1060         err = -EINVAL;
1061         if (file->private_data)
1062                 goto err_unlock;
1063
1064         err = fuse_ctl_add_conn(fc);
1065         if (err)
1066                 goto err_unlock;
1067
1068         list_add_tail(&fc->entry, &fuse_conn_list);
1069         sb->s_root = root_dentry;
1070         fc->connected = 1;
1071         file->private_data = fuse_conn_get(fc);
1072         mutex_unlock(&fuse_mutex);
1073         /*
1074          * atomic_dec_and_test() in fput() provides the necessary
1075          * memory barrier for file->private_data to be visible on all
1076          * CPUs after this
1077          */
1078         fput(file);
1079
1080         fuse_send_init(fc, init_req);
1081
1082         return 0;
1083
1084  err_unlock:
1085         mutex_unlock(&fuse_mutex);
1086  err_free_init_req:
1087         fuse_request_free(init_req);
1088  err_put_root:
1089         dput(root_dentry);
1090  err_put_conn:
1091         fuse_bdi_destroy(fc);
1092         fuse_conn_put(fc);
1093  err_fput:
1094         fput(file);
1095  err:
1096         return err;
1097 }
1098
1099 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1100                        int flags, const char *dev_name,
1101                        void *raw_data)
1102 {
1103         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1104 }
1105
1106 static void fuse_kill_sb_anon(struct super_block *sb)
1107 {
1108         struct fuse_conn *fc = get_fuse_conn_super(sb);
1109
1110         if (fc) {
1111                 down_write(&fc->killsb);
1112                 fc->sb = NULL;
1113                 up_write(&fc->killsb);
1114         }
1115
1116         kill_anon_super(sb);
1117 }
1118
1119 static struct file_system_type fuse_fs_type = {
1120         .owner          = THIS_MODULE,
1121         .name           = "fuse",
1122         .fs_flags       = FS_HAS_SUBTYPE,
1123         .mount          = fuse_mount,
1124         .kill_sb        = fuse_kill_sb_anon,
1125 };
1126 MODULE_ALIAS_FS("fuse");
1127
1128 #ifdef CONFIG_BLOCK
1129 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1130                            int flags, const char *dev_name,
1131                            void *raw_data)
1132 {
1133         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1134 }
1135
1136 static void fuse_kill_sb_blk(struct super_block *sb)
1137 {
1138         struct fuse_conn *fc = get_fuse_conn_super(sb);
1139
1140         if (fc) {
1141                 down_write(&fc->killsb);
1142                 fc->sb = NULL;
1143                 up_write(&fc->killsb);
1144         }
1145
1146         kill_block_super(sb);
1147 }
1148
1149 static struct file_system_type fuseblk_fs_type = {
1150         .owner          = THIS_MODULE,
1151         .name           = "fuseblk",
1152         .mount          = fuse_mount_blk,
1153         .kill_sb        = fuse_kill_sb_blk,
1154         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1155 };
1156 MODULE_ALIAS_FS("fuseblk");
1157
1158 static inline int register_fuseblk(void)
1159 {
1160         return register_filesystem(&fuseblk_fs_type);
1161 }
1162
1163 static inline void unregister_fuseblk(void)
1164 {
1165         unregister_filesystem(&fuseblk_fs_type);
1166 }
1167 #else
1168 static inline int register_fuseblk(void)
1169 {
1170         return 0;
1171 }
1172
1173 static inline void unregister_fuseblk(void)
1174 {
1175 }
1176 #endif
1177
1178 static void fuse_inode_init_once(void *foo)
1179 {
1180         struct inode *inode = foo;
1181
1182         inode_init_once(inode);
1183 }
1184
1185 static int __init fuse_fs_init(void)
1186 {
1187         int err;
1188
1189         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1190                                               sizeof(struct fuse_inode),
1191                                               0, SLAB_HWCACHE_ALIGN,
1192                                               fuse_inode_init_once);
1193         err = -ENOMEM;
1194         if (!fuse_inode_cachep)
1195                 goto out;
1196
1197         err = register_fuseblk();
1198         if (err)
1199                 goto out2;
1200
1201         err = register_filesystem(&fuse_fs_type);
1202         if (err)
1203                 goto out3;
1204
1205         return 0;
1206
1207  out3:
1208         unregister_fuseblk();
1209  out2:
1210         kmem_cache_destroy(fuse_inode_cachep);
1211  out:
1212         return err;
1213 }
1214
1215 static void fuse_fs_cleanup(void)
1216 {
1217         unregister_filesystem(&fuse_fs_type);
1218         unregister_fuseblk();
1219
1220         /*
1221          * Make sure all delayed rcu free inodes are flushed before we
1222          * destroy cache.
1223          */
1224         rcu_barrier();
1225         kmem_cache_destroy(fuse_inode_cachep);
1226 }
1227
1228 static struct kobject *fuse_kobj;
1229 static struct kobject *connections_kobj;
1230
1231 static int fuse_sysfs_init(void)
1232 {
1233         int err;
1234
1235         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1236         if (!fuse_kobj) {
1237                 err = -ENOMEM;
1238                 goto out_err;
1239         }
1240
1241         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1242         if (!connections_kobj) {
1243                 err = -ENOMEM;
1244                 goto out_fuse_unregister;
1245         }
1246
1247         return 0;
1248
1249  out_fuse_unregister:
1250         kobject_put(fuse_kobj);
1251  out_err:
1252         return err;
1253 }
1254
1255 static void fuse_sysfs_cleanup(void)
1256 {
1257         kobject_put(connections_kobj);
1258         kobject_put(fuse_kobj);
1259 }
1260
1261 static int __init fuse_init(void)
1262 {
1263         int res;
1264
1265         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1266                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1267
1268         INIT_LIST_HEAD(&fuse_conn_list);
1269         res = fuse_fs_init();
1270         if (res)
1271                 goto err;
1272
1273         res = fuse_dev_init();
1274         if (res)
1275                 goto err_fs_cleanup;
1276
1277         res = fuse_sysfs_init();
1278         if (res)
1279                 goto err_dev_cleanup;
1280
1281         res = fuse_ctl_init();
1282         if (res)
1283                 goto err_sysfs_cleanup;
1284
1285         sanitize_global_limit(&max_user_bgreq);
1286         sanitize_global_limit(&max_user_congthresh);
1287
1288         return 0;
1289
1290  err_sysfs_cleanup:
1291         fuse_sysfs_cleanup();
1292  err_dev_cleanup:
1293         fuse_dev_cleanup();
1294  err_fs_cleanup:
1295         fuse_fs_cleanup();
1296  err:
1297         return res;
1298 }
1299
1300 static void __exit fuse_exit(void)
1301 {
1302         printk(KERN_DEBUG "fuse exit\n");
1303
1304         fuse_ctl_cleanup();
1305         fuse_sysfs_cleanup();
1306         fuse_fs_cleanup();
1307         fuse_dev_cleanup();
1308 }
1309
1310 module_init(fuse_init);
1311 module_exit(fuse_exit);