Merge branch 'master' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/linville/wirele...
[pandora-kernel.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         unsigned user_id;
64         unsigned group_id;
65         unsigned fd_present:1;
66         unsigned rootmode_present:1;
67         unsigned user_id_present:1;
68         unsigned group_id_present:1;
69         unsigned flags;
70         unsigned max_read;
71         unsigned blksize;
72 };
73
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         INIT_LIST_HEAD(&fi->write_files);
95         INIT_LIST_HEAD(&fi->queued_writes);
96         INIT_LIST_HEAD(&fi->writepages);
97         init_waitqueue_head(&fi->page_waitq);
98         fi->forget = fuse_alloc_forget();
99         if (!fi->forget) {
100                 kmem_cache_free(fuse_inode_cachep, inode);
101                 return NULL;
102         }
103
104         return inode;
105 }
106
107 static void fuse_i_callback(struct rcu_head *head)
108 {
109         struct inode *inode = container_of(head, struct inode, i_rcu);
110         INIT_LIST_HEAD(&inode->i_dentry);
111         kmem_cache_free(fuse_inode_cachep, inode);
112 }
113
114 static void fuse_destroy_inode(struct inode *inode)
115 {
116         struct fuse_inode *fi = get_fuse_inode(inode);
117         BUG_ON(!list_empty(&fi->write_files));
118         BUG_ON(!list_empty(&fi->queued_writes));
119         kfree(fi->forget);
120         call_rcu(&inode->i_rcu, fuse_i_callback);
121 }
122
123 static void fuse_evict_inode(struct inode *inode)
124 {
125         truncate_inode_pages(&inode->i_data, 0);
126         end_writeback(inode);
127         if (inode->i_sb->s_flags & MS_ACTIVE) {
128                 struct fuse_conn *fc = get_fuse_conn(inode);
129                 struct fuse_inode *fi = get_fuse_inode(inode);
130                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
131                 fi->forget = NULL;
132         }
133 }
134
135 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
136 {
137         if (*flags & MS_MANDLOCK)
138                 return -EINVAL;
139
140         return 0;
141 }
142
143 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
144                                    u64 attr_valid)
145 {
146         struct fuse_conn *fc = get_fuse_conn(inode);
147         struct fuse_inode *fi = get_fuse_inode(inode);
148
149         fi->attr_version = ++fc->attr_version;
150         fi->i_time = attr_valid;
151
152         inode->i_ino     = attr->ino;
153         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
154         set_nlink(inode, attr->nlink);
155         inode->i_uid     = attr->uid;
156         inode->i_gid     = attr->gid;
157         inode->i_blocks  = attr->blocks;
158         inode->i_atime.tv_sec   = attr->atime;
159         inode->i_atime.tv_nsec  = attr->atimensec;
160         inode->i_mtime.tv_sec   = attr->mtime;
161         inode->i_mtime.tv_nsec  = attr->mtimensec;
162         inode->i_ctime.tv_sec   = attr->ctime;
163         inode->i_ctime.tv_nsec  = attr->ctimensec;
164
165         if (attr->blksize != 0)
166                 inode->i_blkbits = ilog2(attr->blksize);
167         else
168                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
169
170         /*
171          * Don't set the sticky bit in i_mode, unless we want the VFS
172          * to check permissions.  This prevents failures due to the
173          * check in may_delete().
174          */
175         fi->orig_i_mode = inode->i_mode;
176         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
177                 inode->i_mode &= ~S_ISVTX;
178 }
179
180 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
181                             u64 attr_valid, u64 attr_version)
182 {
183         struct fuse_conn *fc = get_fuse_conn(inode);
184         struct fuse_inode *fi = get_fuse_inode(inode);
185         loff_t oldsize;
186
187         spin_lock(&fc->lock);
188         if (attr_version != 0 && fi->attr_version > attr_version) {
189                 spin_unlock(&fc->lock);
190                 return;
191         }
192
193         fuse_change_attributes_common(inode, attr, attr_valid);
194
195         oldsize = inode->i_size;
196         i_size_write(inode, attr->size);
197         spin_unlock(&fc->lock);
198
199         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
200                 truncate_pagecache(inode, oldsize, attr->size);
201                 invalidate_inode_pages2(inode->i_mapping);
202         }
203 }
204
205 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
206 {
207         inode->i_mode = attr->mode & S_IFMT;
208         inode->i_size = attr->size;
209         if (S_ISREG(inode->i_mode)) {
210                 fuse_init_common(inode);
211                 fuse_init_file_inode(inode);
212         } else if (S_ISDIR(inode->i_mode))
213                 fuse_init_dir(inode);
214         else if (S_ISLNK(inode->i_mode))
215                 fuse_init_symlink(inode);
216         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
217                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
218                 fuse_init_common(inode);
219                 init_special_inode(inode, inode->i_mode,
220                                    new_decode_dev(attr->rdev));
221         } else
222                 BUG();
223 }
224
225 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
226 {
227         u64 nodeid = *(u64 *) _nodeidp;
228         if (get_node_id(inode) == nodeid)
229                 return 1;
230         else
231                 return 0;
232 }
233
234 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
235 {
236         u64 nodeid = *(u64 *) _nodeidp;
237         get_fuse_inode(inode)->nodeid = nodeid;
238         return 0;
239 }
240
241 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
242                         int generation, struct fuse_attr *attr,
243                         u64 attr_valid, u64 attr_version)
244 {
245         struct inode *inode;
246         struct fuse_inode *fi;
247         struct fuse_conn *fc = get_fuse_conn_super(sb);
248
249  retry:
250         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
251         if (!inode)
252                 return NULL;
253
254         if ((inode->i_state & I_NEW)) {
255                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
256                 inode->i_generation = generation;
257                 inode->i_data.backing_dev_info = &fc->bdi;
258                 fuse_init_inode(inode, attr);
259                 unlock_new_inode(inode);
260         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
261                 /* Inode has changed type, any I/O on the old should fail */
262                 make_bad_inode(inode);
263                 iput(inode);
264                 goto retry;
265         }
266
267         fi = get_fuse_inode(inode);
268         spin_lock(&fc->lock);
269         fi->nlookup++;
270         spin_unlock(&fc->lock);
271         fuse_change_attributes(inode, attr, attr_valid, attr_version);
272
273         return inode;
274 }
275
276 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
277                              loff_t offset, loff_t len)
278 {
279         struct inode *inode;
280         pgoff_t pg_start;
281         pgoff_t pg_end;
282
283         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
284         if (!inode)
285                 return -ENOENT;
286
287         fuse_invalidate_attr(inode);
288         if (offset >= 0) {
289                 pg_start = offset >> PAGE_CACHE_SHIFT;
290                 if (len <= 0)
291                         pg_end = -1;
292                 else
293                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
294                 invalidate_inode_pages2_range(inode->i_mapping,
295                                               pg_start, pg_end);
296         }
297         iput(inode);
298         return 0;
299 }
300
301 static void fuse_umount_begin(struct super_block *sb)
302 {
303         fuse_abort_conn(get_fuse_conn_super(sb));
304 }
305
306 static void fuse_send_destroy(struct fuse_conn *fc)
307 {
308         struct fuse_req *req = fc->destroy_req;
309         if (req && fc->conn_init) {
310                 fc->destroy_req = NULL;
311                 req->in.h.opcode = FUSE_DESTROY;
312                 req->force = 1;
313                 fuse_request_send(fc, req);
314                 fuse_put_request(fc, req);
315         }
316 }
317
318 static void fuse_bdi_destroy(struct fuse_conn *fc)
319 {
320         if (fc->bdi_initialized)
321                 bdi_destroy(&fc->bdi);
322 }
323
324 void fuse_conn_kill(struct fuse_conn *fc)
325 {
326         spin_lock(&fc->lock);
327         fc->connected = 0;
328         fc->blocked = 0;
329         spin_unlock(&fc->lock);
330         /* Flush all readers on this fs */
331         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
332         wake_up_all(&fc->waitq);
333         wake_up_all(&fc->blocked_waitq);
334         wake_up_all(&fc->reserved_req_waitq);
335         mutex_lock(&fuse_mutex);
336         list_del(&fc->entry);
337         fuse_ctl_remove_conn(fc);
338         mutex_unlock(&fuse_mutex);
339         fuse_bdi_destroy(fc);
340 }
341 EXPORT_SYMBOL_GPL(fuse_conn_kill);
342
343 static void fuse_put_super(struct super_block *sb)
344 {
345         struct fuse_conn *fc = get_fuse_conn_super(sb);
346
347         fuse_send_destroy(fc);
348         fuse_conn_kill(fc);
349         fuse_conn_put(fc);
350 }
351
352 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
353 {
354         stbuf->f_type    = FUSE_SUPER_MAGIC;
355         stbuf->f_bsize   = attr->bsize;
356         stbuf->f_frsize  = attr->frsize;
357         stbuf->f_blocks  = attr->blocks;
358         stbuf->f_bfree   = attr->bfree;
359         stbuf->f_bavail  = attr->bavail;
360         stbuf->f_files   = attr->files;
361         stbuf->f_ffree   = attr->ffree;
362         stbuf->f_namelen = attr->namelen;
363         /* fsid is left zero */
364 }
365
366 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
367 {
368         struct super_block *sb = dentry->d_sb;
369         struct fuse_conn *fc = get_fuse_conn_super(sb);
370         struct fuse_req *req;
371         struct fuse_statfs_out outarg;
372         int err;
373
374         if (!fuse_allow_task(fc, current)) {
375                 buf->f_type = FUSE_SUPER_MAGIC;
376                 return 0;
377         }
378
379         req = fuse_get_req(fc);
380         if (IS_ERR(req))
381                 return PTR_ERR(req);
382
383         memset(&outarg, 0, sizeof(outarg));
384         req->in.numargs = 0;
385         req->in.h.opcode = FUSE_STATFS;
386         req->in.h.nodeid = get_node_id(dentry->d_inode);
387         req->out.numargs = 1;
388         req->out.args[0].size =
389                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
390         req->out.args[0].value = &outarg;
391         fuse_request_send(fc, req);
392         err = req->out.h.error;
393         if (!err)
394                 convert_fuse_statfs(buf, &outarg.st);
395         fuse_put_request(fc, req);
396         return err;
397 }
398
399 enum {
400         OPT_FD,
401         OPT_ROOTMODE,
402         OPT_USER_ID,
403         OPT_GROUP_ID,
404         OPT_DEFAULT_PERMISSIONS,
405         OPT_ALLOW_OTHER,
406         OPT_MAX_READ,
407         OPT_BLKSIZE,
408         OPT_ERR
409 };
410
411 static const match_table_t tokens = {
412         {OPT_FD,                        "fd=%u"},
413         {OPT_ROOTMODE,                  "rootmode=%o"},
414         {OPT_USER_ID,                   "user_id=%u"},
415         {OPT_GROUP_ID,                  "group_id=%u"},
416         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
417         {OPT_ALLOW_OTHER,               "allow_other"},
418         {OPT_MAX_READ,                  "max_read=%u"},
419         {OPT_BLKSIZE,                   "blksize=%u"},
420         {OPT_ERR,                       NULL}
421 };
422
423 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
424 {
425         char *p;
426         memset(d, 0, sizeof(struct fuse_mount_data));
427         d->max_read = ~0;
428         d->blksize = FUSE_DEFAULT_BLKSIZE;
429
430         while ((p = strsep(&opt, ",")) != NULL) {
431                 int token;
432                 int value;
433                 substring_t args[MAX_OPT_ARGS];
434                 if (!*p)
435                         continue;
436
437                 token = match_token(p, tokens, args);
438                 switch (token) {
439                 case OPT_FD:
440                         if (match_int(&args[0], &value))
441                                 return 0;
442                         d->fd = value;
443                         d->fd_present = 1;
444                         break;
445
446                 case OPT_ROOTMODE:
447                         if (match_octal(&args[0], &value))
448                                 return 0;
449                         if (!fuse_valid_type(value))
450                                 return 0;
451                         d->rootmode = value;
452                         d->rootmode_present = 1;
453                         break;
454
455                 case OPT_USER_ID:
456                         if (match_int(&args[0], &value))
457                                 return 0;
458                         d->user_id = value;
459                         d->user_id_present = 1;
460                         break;
461
462                 case OPT_GROUP_ID:
463                         if (match_int(&args[0], &value))
464                                 return 0;
465                         d->group_id = value;
466                         d->group_id_present = 1;
467                         break;
468
469                 case OPT_DEFAULT_PERMISSIONS:
470                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
471                         break;
472
473                 case OPT_ALLOW_OTHER:
474                         d->flags |= FUSE_ALLOW_OTHER;
475                         break;
476
477                 case OPT_MAX_READ:
478                         if (match_int(&args[0], &value))
479                                 return 0;
480                         d->max_read = value;
481                         break;
482
483                 case OPT_BLKSIZE:
484                         if (!is_bdev || match_int(&args[0], &value))
485                                 return 0;
486                         d->blksize = value;
487                         break;
488
489                 default:
490                         return 0;
491                 }
492         }
493
494         if (!d->fd_present || !d->rootmode_present ||
495             !d->user_id_present || !d->group_id_present)
496                 return 0;
497
498         return 1;
499 }
500
501 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
502 {
503         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
504
505         seq_printf(m, ",user_id=%u", fc->user_id);
506         seq_printf(m, ",group_id=%u", fc->group_id);
507         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
508                 seq_puts(m, ",default_permissions");
509         if (fc->flags & FUSE_ALLOW_OTHER)
510                 seq_puts(m, ",allow_other");
511         if (fc->max_read != ~0)
512                 seq_printf(m, ",max_read=%u", fc->max_read);
513         if (mnt->mnt_sb->s_bdev &&
514             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
515                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
516         return 0;
517 }
518
519 void fuse_conn_init(struct fuse_conn *fc)
520 {
521         memset(fc, 0, sizeof(*fc));
522         spin_lock_init(&fc->lock);
523         mutex_init(&fc->inst_mutex);
524         init_rwsem(&fc->killsb);
525         atomic_set(&fc->count, 1);
526         init_waitqueue_head(&fc->waitq);
527         init_waitqueue_head(&fc->blocked_waitq);
528         init_waitqueue_head(&fc->reserved_req_waitq);
529         INIT_LIST_HEAD(&fc->pending);
530         INIT_LIST_HEAD(&fc->processing);
531         INIT_LIST_HEAD(&fc->io);
532         INIT_LIST_HEAD(&fc->interrupts);
533         INIT_LIST_HEAD(&fc->bg_queue);
534         INIT_LIST_HEAD(&fc->entry);
535         fc->forget_list_tail = &fc->forget_list_head;
536         atomic_set(&fc->num_waiting, 0);
537         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
538         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
539         fc->khctr = 0;
540         fc->polled_files = RB_ROOT;
541         fc->reqctr = 0;
542         fc->blocked = 1;
543         fc->attr_version = 1;
544         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
545 }
546 EXPORT_SYMBOL_GPL(fuse_conn_init);
547
548 void fuse_conn_put(struct fuse_conn *fc)
549 {
550         if (atomic_dec_and_test(&fc->count)) {
551                 if (fc->destroy_req)
552                         fuse_request_free(fc->destroy_req);
553                 mutex_destroy(&fc->inst_mutex);
554                 fc->release(fc);
555         }
556 }
557 EXPORT_SYMBOL_GPL(fuse_conn_put);
558
559 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
560 {
561         atomic_inc(&fc->count);
562         return fc;
563 }
564 EXPORT_SYMBOL_GPL(fuse_conn_get);
565
566 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
567 {
568         struct fuse_attr attr;
569         memset(&attr, 0, sizeof(attr));
570
571         attr.mode = mode;
572         attr.ino = FUSE_ROOT_ID;
573         attr.nlink = 1;
574         return fuse_iget(sb, 1, 0, &attr, 0, 0);
575 }
576
577 struct fuse_inode_handle {
578         u64 nodeid;
579         u32 generation;
580 };
581
582 static struct dentry *fuse_get_dentry(struct super_block *sb,
583                                       struct fuse_inode_handle *handle)
584 {
585         struct fuse_conn *fc = get_fuse_conn_super(sb);
586         struct inode *inode;
587         struct dentry *entry;
588         int err = -ESTALE;
589
590         if (handle->nodeid == 0)
591                 goto out_err;
592
593         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
594         if (!inode) {
595                 struct fuse_entry_out outarg;
596                 struct qstr name;
597
598                 if (!fc->export_support)
599                         goto out_err;
600
601                 name.len = 1;
602                 name.name = ".";
603                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
604                                        &inode);
605                 if (err && err != -ENOENT)
606                         goto out_err;
607                 if (err || !inode) {
608                         err = -ESTALE;
609                         goto out_err;
610                 }
611                 err = -EIO;
612                 if (get_node_id(inode) != handle->nodeid)
613                         goto out_iput;
614         }
615         err = -ESTALE;
616         if (inode->i_generation != handle->generation)
617                 goto out_iput;
618
619         entry = d_obtain_alias(inode);
620         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
621                 fuse_invalidate_entry_cache(entry);
622
623         return entry;
624
625  out_iput:
626         iput(inode);
627  out_err:
628         return ERR_PTR(err);
629 }
630
631 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
632                            int connectable)
633 {
634         struct inode *inode = dentry->d_inode;
635         bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
636         int len = encode_parent ? 6 : 3;
637         u64 nodeid;
638         u32 generation;
639
640         if (*max_len < len) {
641                 *max_len = len;
642                 return  255;
643         }
644
645         nodeid = get_fuse_inode(inode)->nodeid;
646         generation = inode->i_generation;
647
648         fh[0] = (u32)(nodeid >> 32);
649         fh[1] = (u32)(nodeid & 0xffffffff);
650         fh[2] = generation;
651
652         if (encode_parent) {
653                 struct inode *parent;
654
655                 spin_lock(&dentry->d_lock);
656                 parent = dentry->d_parent->d_inode;
657                 nodeid = get_fuse_inode(parent)->nodeid;
658                 generation = parent->i_generation;
659                 spin_unlock(&dentry->d_lock);
660
661                 fh[3] = (u32)(nodeid >> 32);
662                 fh[4] = (u32)(nodeid & 0xffffffff);
663                 fh[5] = generation;
664         }
665
666         *max_len = len;
667         return encode_parent ? 0x82 : 0x81;
668 }
669
670 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
671                 struct fid *fid, int fh_len, int fh_type)
672 {
673         struct fuse_inode_handle handle;
674
675         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
676                 return NULL;
677
678         handle.nodeid = (u64) fid->raw[0] << 32;
679         handle.nodeid |= (u64) fid->raw[1];
680         handle.generation = fid->raw[2];
681         return fuse_get_dentry(sb, &handle);
682 }
683
684 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
685                 struct fid *fid, int fh_len, int fh_type)
686 {
687         struct fuse_inode_handle parent;
688
689         if (fh_type != 0x82 || fh_len < 6)
690                 return NULL;
691
692         parent.nodeid = (u64) fid->raw[3] << 32;
693         parent.nodeid |= (u64) fid->raw[4];
694         parent.generation = fid->raw[5];
695         return fuse_get_dentry(sb, &parent);
696 }
697
698 static struct dentry *fuse_get_parent(struct dentry *child)
699 {
700         struct inode *child_inode = child->d_inode;
701         struct fuse_conn *fc = get_fuse_conn(child_inode);
702         struct inode *inode;
703         struct dentry *parent;
704         struct fuse_entry_out outarg;
705         struct qstr name;
706         int err;
707
708         if (!fc->export_support)
709                 return ERR_PTR(-ESTALE);
710
711         name.len = 2;
712         name.name = "..";
713         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
714                                &name, &outarg, &inode);
715         if (err) {
716                 if (err == -ENOENT)
717                         return ERR_PTR(-ESTALE);
718                 return ERR_PTR(err);
719         }
720
721         parent = d_obtain_alias(inode);
722         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
723                 fuse_invalidate_entry_cache(parent);
724
725         return parent;
726 }
727
728 static const struct export_operations fuse_export_operations = {
729         .fh_to_dentry   = fuse_fh_to_dentry,
730         .fh_to_parent   = fuse_fh_to_parent,
731         .encode_fh      = fuse_encode_fh,
732         .get_parent     = fuse_get_parent,
733 };
734
735 static const struct super_operations fuse_super_operations = {
736         .alloc_inode    = fuse_alloc_inode,
737         .destroy_inode  = fuse_destroy_inode,
738         .evict_inode    = fuse_evict_inode,
739         .drop_inode     = generic_delete_inode,
740         .remount_fs     = fuse_remount_fs,
741         .put_super      = fuse_put_super,
742         .umount_begin   = fuse_umount_begin,
743         .statfs         = fuse_statfs,
744         .show_options   = fuse_show_options,
745 };
746
747 static void sanitize_global_limit(unsigned *limit)
748 {
749         if (*limit == 0)
750                 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
751                          sizeof(struct fuse_req);
752
753         if (*limit >= 1 << 16)
754                 *limit = (1 << 16) - 1;
755 }
756
757 static int set_global_limit(const char *val, struct kernel_param *kp)
758 {
759         int rv;
760
761         rv = param_set_uint(val, kp);
762         if (rv)
763                 return rv;
764
765         sanitize_global_limit((unsigned *)kp->arg);
766
767         return 0;
768 }
769
770 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
771 {
772         int cap_sys_admin = capable(CAP_SYS_ADMIN);
773
774         if (arg->minor < 13)
775                 return;
776
777         sanitize_global_limit(&max_user_bgreq);
778         sanitize_global_limit(&max_user_congthresh);
779
780         if (arg->max_background) {
781                 fc->max_background = arg->max_background;
782
783                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
784                         fc->max_background = max_user_bgreq;
785         }
786         if (arg->congestion_threshold) {
787                 fc->congestion_threshold = arg->congestion_threshold;
788
789                 if (!cap_sys_admin &&
790                     fc->congestion_threshold > max_user_congthresh)
791                         fc->congestion_threshold = max_user_congthresh;
792         }
793 }
794
795 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
796 {
797         struct fuse_init_out *arg = &req->misc.init_out;
798
799         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
800                 fc->conn_error = 1;
801         else {
802                 unsigned long ra_pages;
803
804                 process_init_limits(fc, arg);
805
806                 if (arg->minor >= 6) {
807                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
808                         if (arg->flags & FUSE_ASYNC_READ)
809                                 fc->async_read = 1;
810                         if (!(arg->flags & FUSE_POSIX_LOCKS))
811                                 fc->no_lock = 1;
812                         if (arg->minor >= 17) {
813                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
814                                         fc->no_flock = 1;
815                         } else {
816                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
817                                         fc->no_flock = 1;
818                         }
819                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
820                                 fc->atomic_o_trunc = 1;
821                         if (arg->minor >= 9) {
822                                 /* LOOKUP has dependency on proto version */
823                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
824                                         fc->export_support = 1;
825                         }
826                         if (arg->flags & FUSE_BIG_WRITES)
827                                 fc->big_writes = 1;
828                         if (arg->flags & FUSE_DONT_MASK)
829                                 fc->dont_mask = 1;
830                 } else {
831                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
832                         fc->no_lock = 1;
833                         fc->no_flock = 1;
834                 }
835
836                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
837                 fc->minor = arg->minor;
838                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
839                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
840                 fc->conn_init = 1;
841         }
842         fc->blocked = 0;
843         wake_up_all(&fc->blocked_waitq);
844 }
845
846 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
847 {
848         struct fuse_init_in *arg = &req->misc.init_in;
849
850         arg->major = FUSE_KERNEL_VERSION;
851         arg->minor = FUSE_KERNEL_MINOR_VERSION;
852         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
853         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
854                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
855                 FUSE_FLOCK_LOCKS;
856         req->in.h.opcode = FUSE_INIT;
857         req->in.numargs = 1;
858         req->in.args[0].size = sizeof(*arg);
859         req->in.args[0].value = arg;
860         req->out.numargs = 1;
861         /* Variable length argument used for backward compatibility
862            with interface version < 7.5.  Rest of init_out is zeroed
863            by do_get_request(), so a short reply is not a problem */
864         req->out.argvar = 1;
865         req->out.args[0].size = sizeof(struct fuse_init_out);
866         req->out.args[0].value = &req->misc.init_out;
867         req->end = process_init_reply;
868         fuse_request_send_background(fc, req);
869 }
870
871 static void fuse_free_conn(struct fuse_conn *fc)
872 {
873         kfree(fc);
874 }
875
876 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
877 {
878         int err;
879
880         fc->bdi.name = "fuse";
881         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
882         /* fuse does it's own writeback accounting */
883         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
884
885         err = bdi_init(&fc->bdi);
886         if (err)
887                 return err;
888
889         fc->bdi_initialized = 1;
890
891         if (sb->s_bdev) {
892                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
893                                     MAJOR(fc->dev), MINOR(fc->dev));
894         } else {
895                 err = bdi_register_dev(&fc->bdi, fc->dev);
896         }
897
898         if (err)
899                 return err;
900
901         /*
902          * For a single fuse filesystem use max 1% of dirty +
903          * writeback threshold.
904          *
905          * This gives about 1M of write buffer for memory maps on a
906          * machine with 1G and 10% dirty_ratio, which should be more
907          * than enough.
908          *
909          * Privileged users can raise it by writing to
910          *
911          *    /sys/class/bdi/<bdi>/max_ratio
912          */
913         bdi_set_max_ratio(&fc->bdi, 1);
914
915         return 0;
916 }
917
918 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
919 {
920         struct fuse_conn *fc;
921         struct inode *root;
922         struct fuse_mount_data d;
923         struct file *file;
924         struct dentry *root_dentry;
925         struct fuse_req *init_req;
926         int err;
927         int is_bdev = sb->s_bdev != NULL;
928
929         err = -EINVAL;
930         if (sb->s_flags & MS_MANDLOCK)
931                 goto err;
932
933         sb->s_flags &= ~MS_NOSEC;
934
935         if (!parse_fuse_opt((char *) data, &d, is_bdev))
936                 goto err;
937
938         if (is_bdev) {
939 #ifdef CONFIG_BLOCK
940                 err = -EINVAL;
941                 if (!sb_set_blocksize(sb, d.blksize))
942                         goto err;
943 #endif
944         } else {
945                 sb->s_blocksize = PAGE_CACHE_SIZE;
946                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
947         }
948         sb->s_magic = FUSE_SUPER_MAGIC;
949         sb->s_op = &fuse_super_operations;
950         sb->s_maxbytes = MAX_LFS_FILESIZE;
951         sb->s_export_op = &fuse_export_operations;
952
953         file = fget(d.fd);
954         err = -EINVAL;
955         if (!file)
956                 goto err;
957
958         if (file->f_op != &fuse_dev_operations)
959                 goto err_fput;
960
961         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
962         err = -ENOMEM;
963         if (!fc)
964                 goto err_fput;
965
966         fuse_conn_init(fc);
967
968         fc->dev = sb->s_dev;
969         fc->sb = sb;
970         err = fuse_bdi_init(fc, sb);
971         if (err)
972                 goto err_put_conn;
973
974         sb->s_bdi = &fc->bdi;
975
976         /* Handle umasking inside the fuse code */
977         if (sb->s_flags & MS_POSIXACL)
978                 fc->dont_mask = 1;
979         sb->s_flags |= MS_POSIXACL;
980
981         fc->release = fuse_free_conn;
982         fc->flags = d.flags;
983         fc->user_id = d.user_id;
984         fc->group_id = d.group_id;
985         fc->max_read = max_t(unsigned, 4096, d.max_read);
986
987         /* Used by get_root_inode() */
988         sb->s_fs_info = fc;
989
990         err = -ENOMEM;
991         root = fuse_get_root_inode(sb, d.rootmode);
992         if (!root)
993                 goto err_put_conn;
994
995         root_dentry = d_alloc_root(root);
996         if (!root_dentry) {
997                 iput(root);
998                 goto err_put_conn;
999         }
1000         /* only now - we want root dentry with NULL ->d_op */
1001         sb->s_d_op = &fuse_dentry_operations;
1002
1003         init_req = fuse_request_alloc();
1004         if (!init_req)
1005                 goto err_put_root;
1006
1007         if (is_bdev) {
1008                 fc->destroy_req = fuse_request_alloc();
1009                 if (!fc->destroy_req)
1010                         goto err_free_init_req;
1011         }
1012
1013         mutex_lock(&fuse_mutex);
1014         err = -EINVAL;
1015         if (file->private_data)
1016                 goto err_unlock;
1017
1018         err = fuse_ctl_add_conn(fc);
1019         if (err)
1020                 goto err_unlock;
1021
1022         list_add_tail(&fc->entry, &fuse_conn_list);
1023         sb->s_root = root_dentry;
1024         fc->connected = 1;
1025         file->private_data = fuse_conn_get(fc);
1026         mutex_unlock(&fuse_mutex);
1027         /*
1028          * atomic_dec_and_test() in fput() provides the necessary
1029          * memory barrier for file->private_data to be visible on all
1030          * CPUs after this
1031          */
1032         fput(file);
1033
1034         fuse_send_init(fc, init_req);
1035
1036         return 0;
1037
1038  err_unlock:
1039         mutex_unlock(&fuse_mutex);
1040  err_free_init_req:
1041         fuse_request_free(init_req);
1042  err_put_root:
1043         dput(root_dentry);
1044  err_put_conn:
1045         fuse_bdi_destroy(fc);
1046         fuse_conn_put(fc);
1047  err_fput:
1048         fput(file);
1049  err:
1050         return err;
1051 }
1052
1053 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1054                        int flags, const char *dev_name,
1055                        void *raw_data)
1056 {
1057         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1058 }
1059
1060 static void fuse_kill_sb_anon(struct super_block *sb)
1061 {
1062         struct fuse_conn *fc = get_fuse_conn_super(sb);
1063
1064         if (fc) {
1065                 down_write(&fc->killsb);
1066                 fc->sb = NULL;
1067                 up_write(&fc->killsb);
1068         }
1069
1070         kill_anon_super(sb);
1071 }
1072
1073 static struct file_system_type fuse_fs_type = {
1074         .owner          = THIS_MODULE,
1075         .name           = "fuse",
1076         .fs_flags       = FS_HAS_SUBTYPE,
1077         .mount          = fuse_mount,
1078         .kill_sb        = fuse_kill_sb_anon,
1079 };
1080
1081 #ifdef CONFIG_BLOCK
1082 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1083                            int flags, const char *dev_name,
1084                            void *raw_data)
1085 {
1086         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1087 }
1088
1089 static void fuse_kill_sb_blk(struct super_block *sb)
1090 {
1091         struct fuse_conn *fc = get_fuse_conn_super(sb);
1092
1093         if (fc) {
1094                 down_write(&fc->killsb);
1095                 fc->sb = NULL;
1096                 up_write(&fc->killsb);
1097         }
1098
1099         kill_block_super(sb);
1100 }
1101
1102 static struct file_system_type fuseblk_fs_type = {
1103         .owner          = THIS_MODULE,
1104         .name           = "fuseblk",
1105         .mount          = fuse_mount_blk,
1106         .kill_sb        = fuse_kill_sb_blk,
1107         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1108 };
1109
1110 static inline int register_fuseblk(void)
1111 {
1112         return register_filesystem(&fuseblk_fs_type);
1113 }
1114
1115 static inline void unregister_fuseblk(void)
1116 {
1117         unregister_filesystem(&fuseblk_fs_type);
1118 }
1119 #else
1120 static inline int register_fuseblk(void)
1121 {
1122         return 0;
1123 }
1124
1125 static inline void unregister_fuseblk(void)
1126 {
1127 }
1128 #endif
1129
1130 static void fuse_inode_init_once(void *foo)
1131 {
1132         struct inode *inode = foo;
1133
1134         inode_init_once(inode);
1135 }
1136
1137 static int __init fuse_fs_init(void)
1138 {
1139         int err;
1140
1141         err = register_filesystem(&fuse_fs_type);
1142         if (err)
1143                 goto out;
1144
1145         err = register_fuseblk();
1146         if (err)
1147                 goto out_unreg;
1148
1149         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1150                                               sizeof(struct fuse_inode),
1151                                               0, SLAB_HWCACHE_ALIGN,
1152                                               fuse_inode_init_once);
1153         err = -ENOMEM;
1154         if (!fuse_inode_cachep)
1155                 goto out_unreg2;
1156
1157         return 0;
1158
1159  out_unreg2:
1160         unregister_fuseblk();
1161  out_unreg:
1162         unregister_filesystem(&fuse_fs_type);
1163  out:
1164         return err;
1165 }
1166
1167 static void fuse_fs_cleanup(void)
1168 {
1169         unregister_filesystem(&fuse_fs_type);
1170         unregister_fuseblk();
1171         kmem_cache_destroy(fuse_inode_cachep);
1172 }
1173
1174 static struct kobject *fuse_kobj;
1175 static struct kobject *connections_kobj;
1176
1177 static int fuse_sysfs_init(void)
1178 {
1179         int err;
1180
1181         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1182         if (!fuse_kobj) {
1183                 err = -ENOMEM;
1184                 goto out_err;
1185         }
1186
1187         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1188         if (!connections_kobj) {
1189                 err = -ENOMEM;
1190                 goto out_fuse_unregister;
1191         }
1192
1193         return 0;
1194
1195  out_fuse_unregister:
1196         kobject_put(fuse_kobj);
1197  out_err:
1198         return err;
1199 }
1200
1201 static void fuse_sysfs_cleanup(void)
1202 {
1203         kobject_put(connections_kobj);
1204         kobject_put(fuse_kobj);
1205 }
1206
1207 static int __init fuse_init(void)
1208 {
1209         int res;
1210
1211         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1212                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1213
1214         INIT_LIST_HEAD(&fuse_conn_list);
1215         res = fuse_fs_init();
1216         if (res)
1217                 goto err;
1218
1219         res = fuse_dev_init();
1220         if (res)
1221                 goto err_fs_cleanup;
1222
1223         res = fuse_sysfs_init();
1224         if (res)
1225                 goto err_dev_cleanup;
1226
1227         res = fuse_ctl_init();
1228         if (res)
1229                 goto err_sysfs_cleanup;
1230
1231         sanitize_global_limit(&max_user_bgreq);
1232         sanitize_global_limit(&max_user_congthresh);
1233
1234         return 0;
1235
1236  err_sysfs_cleanup:
1237         fuse_sysfs_cleanup();
1238  err_dev_cleanup:
1239         fuse_dev_cleanup();
1240  err_fs_cleanup:
1241         fuse_fs_cleanup();
1242  err:
1243         return res;
1244 }
1245
1246 static void __exit fuse_exit(void)
1247 {
1248         printk(KERN_DEBUG "fuse exit\n");
1249
1250         fuse_ctl_cleanup();
1251         fuse_sysfs_cleanup();
1252         fuse_fs_cleanup();
1253         fuse_dev_cleanup();
1254 }
1255
1256 module_init(fuse_init);
1257 module_exit(fuse_exit);