Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi...
[linux-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         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 static struct inode *fuse_alloc_inode(struct super_block *sb)
75 {
76         struct inode *inode;
77         struct fuse_inode *fi;
78
79         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
80         if (!inode)
81                 return NULL;
82
83         fi = get_fuse_inode(inode);
84         fi->i_time = 0;
85         fi->nodeid = 0;
86         fi->nlookup = 0;
87         fi->attr_version = 0;
88         fi->writectr = 0;
89         INIT_LIST_HEAD(&fi->write_files);
90         INIT_LIST_HEAD(&fi->queued_writes);
91         INIT_LIST_HEAD(&fi->writepages);
92         init_waitqueue_head(&fi->page_waitq);
93         fi->forget_req = fuse_request_alloc();
94         if (!fi->forget_req) {
95                 kmem_cache_free(fuse_inode_cachep, inode);
96                 return NULL;
97         }
98
99         return inode;
100 }
101
102 static void fuse_destroy_inode(struct inode *inode)
103 {
104         struct fuse_inode *fi = get_fuse_inode(inode);
105         BUG_ON(!list_empty(&fi->write_files));
106         BUG_ON(!list_empty(&fi->queued_writes));
107         if (fi->forget_req)
108                 fuse_request_free(fi->forget_req);
109         kmem_cache_free(fuse_inode_cachep, inode);
110 }
111
112 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
113                       u64 nodeid, u64 nlookup)
114 {
115         struct fuse_forget_in *inarg = &req->misc.forget_in;
116         inarg->nlookup = nlookup;
117         req->in.h.opcode = FUSE_FORGET;
118         req->in.h.nodeid = nodeid;
119         req->in.numargs = 1;
120         req->in.args[0].size = sizeof(struct fuse_forget_in);
121         req->in.args[0].value = inarg;
122         fuse_request_send_noreply(fc, req);
123 }
124
125 static void fuse_clear_inode(struct inode *inode)
126 {
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_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
131                 fi->forget_req = 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_truncate(struct address_space *mapping, loff_t offset)
144 {
145         /* See vmtruncate() */
146         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
147         truncate_inode_pages(mapping, offset);
148         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
149 }
150
151 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
152                                    u64 attr_valid)
153 {
154         struct fuse_conn *fc = get_fuse_conn(inode);
155         struct fuse_inode *fi = get_fuse_inode(inode);
156
157         fi->attr_version = ++fc->attr_version;
158         fi->i_time = attr_valid;
159
160         inode->i_ino     = attr->ino;
161         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
162         inode->i_nlink   = attr->nlink;
163         inode->i_uid     = attr->uid;
164         inode->i_gid     = attr->gid;
165         inode->i_blocks  = attr->blocks;
166         inode->i_atime.tv_sec   = attr->atime;
167         inode->i_atime.tv_nsec  = attr->atimensec;
168         inode->i_mtime.tv_sec   = attr->mtime;
169         inode->i_mtime.tv_nsec  = attr->mtimensec;
170         inode->i_ctime.tv_sec   = attr->ctime;
171         inode->i_ctime.tv_nsec  = attr->ctimensec;
172
173         if (attr->blksize != 0)
174                 inode->i_blkbits = ilog2(attr->blksize);
175         else
176                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
177
178         /*
179          * Don't set the sticky bit in i_mode, unless we want the VFS
180          * to check permissions.  This prevents failures due to the
181          * check in may_delete().
182          */
183         fi->orig_i_mode = inode->i_mode;
184         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
185                 inode->i_mode &= ~S_ISVTX;
186 }
187
188 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
189                             u64 attr_valid, u64 attr_version)
190 {
191         struct fuse_conn *fc = get_fuse_conn(inode);
192         struct fuse_inode *fi = get_fuse_inode(inode);
193         loff_t oldsize;
194
195         spin_lock(&fc->lock);
196         if (attr_version != 0 && fi->attr_version > attr_version) {
197                 spin_unlock(&fc->lock);
198                 return;
199         }
200
201         fuse_change_attributes_common(inode, attr, attr_valid);
202
203         oldsize = inode->i_size;
204         i_size_write(inode, attr->size);
205         spin_unlock(&fc->lock);
206
207         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
208                 if (attr->size < oldsize)
209                         fuse_truncate(inode->i_mapping, attr->size);
210                 invalidate_inode_pages2(inode->i_mapping);
211         }
212 }
213
214 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
215 {
216         inode->i_mode = attr->mode & S_IFMT;
217         inode->i_size = attr->size;
218         if (S_ISREG(inode->i_mode)) {
219                 fuse_init_common(inode);
220                 fuse_init_file_inode(inode);
221         } else if (S_ISDIR(inode->i_mode))
222                 fuse_init_dir(inode);
223         else if (S_ISLNK(inode->i_mode))
224                 fuse_init_symlink(inode);
225         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
226                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
227                 fuse_init_common(inode);
228                 init_special_inode(inode, inode->i_mode,
229                                    new_decode_dev(attr->rdev));
230         } else
231                 BUG();
232 }
233
234 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
235 {
236         u64 nodeid = *(u64 *) _nodeidp;
237         if (get_node_id(inode) == nodeid)
238                 return 1;
239         else
240                 return 0;
241 }
242
243 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
244 {
245         u64 nodeid = *(u64 *) _nodeidp;
246         get_fuse_inode(inode)->nodeid = nodeid;
247         return 0;
248 }
249
250 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
251                         int generation, struct fuse_attr *attr,
252                         u64 attr_valid, u64 attr_version)
253 {
254         struct inode *inode;
255         struct fuse_inode *fi;
256         struct fuse_conn *fc = get_fuse_conn_super(sb);
257
258  retry:
259         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
260         if (!inode)
261                 return NULL;
262
263         if ((inode->i_state & I_NEW)) {
264                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
265                 inode->i_generation = generation;
266                 inode->i_data.backing_dev_info = &fc->bdi;
267                 fuse_init_inode(inode, attr);
268                 unlock_new_inode(inode);
269         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
270                 /* Inode has changed type, any I/O on the old should fail */
271                 make_bad_inode(inode);
272                 iput(inode);
273                 goto retry;
274         }
275
276         fi = get_fuse_inode(inode);
277         spin_lock(&fc->lock);
278         fi->nlookup++;
279         spin_unlock(&fc->lock);
280         fuse_change_attributes(inode, attr, attr_valid, attr_version);
281
282         return inode;
283 }
284
285 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
286                              loff_t offset, loff_t len)
287 {
288         struct inode *inode;
289         pgoff_t pg_start;
290         pgoff_t pg_end;
291
292         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
293         if (!inode)
294                 return -ENOENT;
295
296         fuse_invalidate_attr(inode);
297         if (offset >= 0) {
298                 pg_start = offset >> PAGE_CACHE_SHIFT;
299                 if (len <= 0)
300                         pg_end = -1;
301                 else
302                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
303                 invalidate_inode_pages2_range(inode->i_mapping,
304                                               pg_start, pg_end);
305         }
306         iput(inode);
307         return 0;
308 }
309
310 static void fuse_umount_begin(struct super_block *sb)
311 {
312         fuse_abort_conn(get_fuse_conn_super(sb));
313 }
314
315 static void fuse_send_destroy(struct fuse_conn *fc)
316 {
317         struct fuse_req *req = fc->destroy_req;
318         if (req && fc->conn_init) {
319                 fc->destroy_req = NULL;
320                 req->in.h.opcode = FUSE_DESTROY;
321                 req->force = 1;
322                 fuse_request_send(fc, req);
323                 fuse_put_request(fc, req);
324         }
325 }
326
327 static void fuse_bdi_destroy(struct fuse_conn *fc)
328 {
329         if (fc->bdi_initialized)
330                 bdi_destroy(&fc->bdi);
331 }
332
333 void fuse_conn_kill(struct fuse_conn *fc)
334 {
335         spin_lock(&fc->lock);
336         fc->connected = 0;
337         fc->blocked = 0;
338         spin_unlock(&fc->lock);
339         /* Flush all readers on this fs */
340         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
341         wake_up_all(&fc->waitq);
342         wake_up_all(&fc->blocked_waitq);
343         wake_up_all(&fc->reserved_req_waitq);
344         mutex_lock(&fuse_mutex);
345         list_del(&fc->entry);
346         fuse_ctl_remove_conn(fc);
347         mutex_unlock(&fuse_mutex);
348         fuse_bdi_destroy(fc);
349 }
350 EXPORT_SYMBOL_GPL(fuse_conn_kill);
351
352 static void fuse_put_super(struct super_block *sb)
353 {
354         struct fuse_conn *fc = get_fuse_conn_super(sb);
355
356         fuse_send_destroy(fc);
357         fuse_conn_kill(fc);
358         fuse_conn_put(fc);
359 }
360
361 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
362 {
363         stbuf->f_type    = FUSE_SUPER_MAGIC;
364         stbuf->f_bsize   = attr->bsize;
365         stbuf->f_frsize  = attr->frsize;
366         stbuf->f_blocks  = attr->blocks;
367         stbuf->f_bfree   = attr->bfree;
368         stbuf->f_bavail  = attr->bavail;
369         stbuf->f_files   = attr->files;
370         stbuf->f_ffree   = attr->ffree;
371         stbuf->f_namelen = attr->namelen;
372         /* fsid is left zero */
373 }
374
375 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
376 {
377         struct super_block *sb = dentry->d_sb;
378         struct fuse_conn *fc = get_fuse_conn_super(sb);
379         struct fuse_req *req;
380         struct fuse_statfs_out outarg;
381         int err;
382
383         if (!fuse_allow_task(fc, current)) {
384                 buf->f_type = FUSE_SUPER_MAGIC;
385                 return 0;
386         }
387
388         req = fuse_get_req(fc);
389         if (IS_ERR(req))
390                 return PTR_ERR(req);
391
392         memset(&outarg, 0, sizeof(outarg));
393         req->in.numargs = 0;
394         req->in.h.opcode = FUSE_STATFS;
395         req->in.h.nodeid = get_node_id(dentry->d_inode);
396         req->out.numargs = 1;
397         req->out.args[0].size =
398                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
399         req->out.args[0].value = &outarg;
400         fuse_request_send(fc, req);
401         err = req->out.h.error;
402         if (!err)
403                 convert_fuse_statfs(buf, &outarg.st);
404         fuse_put_request(fc, req);
405         return err;
406 }
407
408 enum {
409         OPT_FD,
410         OPT_ROOTMODE,
411         OPT_USER_ID,
412         OPT_GROUP_ID,
413         OPT_DEFAULT_PERMISSIONS,
414         OPT_ALLOW_OTHER,
415         OPT_MAX_READ,
416         OPT_BLKSIZE,
417         OPT_ERR
418 };
419
420 static const match_table_t tokens = {
421         {OPT_FD,                        "fd=%u"},
422         {OPT_ROOTMODE,                  "rootmode=%o"},
423         {OPT_USER_ID,                   "user_id=%u"},
424         {OPT_GROUP_ID,                  "group_id=%u"},
425         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
426         {OPT_ALLOW_OTHER,               "allow_other"},
427         {OPT_MAX_READ,                  "max_read=%u"},
428         {OPT_BLKSIZE,                   "blksize=%u"},
429         {OPT_ERR,                       NULL}
430 };
431
432 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
433 {
434         char *p;
435         memset(d, 0, sizeof(struct fuse_mount_data));
436         d->max_read = ~0;
437         d->blksize = FUSE_DEFAULT_BLKSIZE;
438
439         while ((p = strsep(&opt, ",")) != NULL) {
440                 int token;
441                 int value;
442                 substring_t args[MAX_OPT_ARGS];
443                 if (!*p)
444                         continue;
445
446                 token = match_token(p, tokens, args);
447                 switch (token) {
448                 case OPT_FD:
449                         if (match_int(&args[0], &value))
450                                 return 0;
451                         d->fd = value;
452                         d->fd_present = 1;
453                         break;
454
455                 case OPT_ROOTMODE:
456                         if (match_octal(&args[0], &value))
457                                 return 0;
458                         if (!fuse_valid_type(value))
459                                 return 0;
460                         d->rootmode = value;
461                         d->rootmode_present = 1;
462                         break;
463
464                 case OPT_USER_ID:
465                         if (match_int(&args[0], &value))
466                                 return 0;
467                         d->user_id = value;
468                         d->user_id_present = 1;
469                         break;
470
471                 case OPT_GROUP_ID:
472                         if (match_int(&args[0], &value))
473                                 return 0;
474                         d->group_id = value;
475                         d->group_id_present = 1;
476                         break;
477
478                 case OPT_DEFAULT_PERMISSIONS:
479                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
480                         break;
481
482                 case OPT_ALLOW_OTHER:
483                         d->flags |= FUSE_ALLOW_OTHER;
484                         break;
485
486                 case OPT_MAX_READ:
487                         if (match_int(&args[0], &value))
488                                 return 0;
489                         d->max_read = value;
490                         break;
491
492                 case OPT_BLKSIZE:
493                         if (!is_bdev || match_int(&args[0], &value))
494                                 return 0;
495                         d->blksize = value;
496                         break;
497
498                 default:
499                         return 0;
500                 }
501         }
502
503         if (!d->fd_present || !d->rootmode_present ||
504             !d->user_id_present || !d->group_id_present)
505                 return 0;
506
507         return 1;
508 }
509
510 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
511 {
512         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
513
514         seq_printf(m, ",user_id=%u", fc->user_id);
515         seq_printf(m, ",group_id=%u", fc->group_id);
516         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
517                 seq_puts(m, ",default_permissions");
518         if (fc->flags & FUSE_ALLOW_OTHER)
519                 seq_puts(m, ",allow_other");
520         if (fc->max_read != ~0)
521                 seq_printf(m, ",max_read=%u", fc->max_read);
522         if (mnt->mnt_sb->s_bdev &&
523             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
524                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
525         return 0;
526 }
527
528 void fuse_conn_init(struct fuse_conn *fc)
529 {
530         memset(fc, 0, sizeof(*fc));
531         spin_lock_init(&fc->lock);
532         mutex_init(&fc->inst_mutex);
533         init_rwsem(&fc->killsb);
534         atomic_set(&fc->count, 1);
535         init_waitqueue_head(&fc->waitq);
536         init_waitqueue_head(&fc->blocked_waitq);
537         init_waitqueue_head(&fc->reserved_req_waitq);
538         INIT_LIST_HEAD(&fc->pending);
539         INIT_LIST_HEAD(&fc->processing);
540         INIT_LIST_HEAD(&fc->io);
541         INIT_LIST_HEAD(&fc->interrupts);
542         INIT_LIST_HEAD(&fc->bg_queue);
543         INIT_LIST_HEAD(&fc->entry);
544         atomic_set(&fc->num_waiting, 0);
545         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
546         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
547         fc->khctr = 0;
548         fc->polled_files = RB_ROOT;
549         fc->reqctr = 0;
550         fc->blocked = 1;
551         fc->attr_version = 1;
552         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
553 }
554 EXPORT_SYMBOL_GPL(fuse_conn_init);
555
556 void fuse_conn_put(struct fuse_conn *fc)
557 {
558         if (atomic_dec_and_test(&fc->count)) {
559                 if (fc->destroy_req)
560                         fuse_request_free(fc->destroy_req);
561                 mutex_destroy(&fc->inst_mutex);
562                 fc->release(fc);
563         }
564 }
565 EXPORT_SYMBOL_GPL(fuse_conn_put);
566
567 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
568 {
569         atomic_inc(&fc->count);
570         return fc;
571 }
572 EXPORT_SYMBOL_GPL(fuse_conn_get);
573
574 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
575 {
576         struct fuse_attr attr;
577         memset(&attr, 0, sizeof(attr));
578
579         attr.mode = mode;
580         attr.ino = FUSE_ROOT_ID;
581         attr.nlink = 1;
582         return fuse_iget(sb, 1, 0, &attr, 0, 0);
583 }
584
585 struct fuse_inode_handle {
586         u64 nodeid;
587         u32 generation;
588 };
589
590 static struct dentry *fuse_get_dentry(struct super_block *sb,
591                                       struct fuse_inode_handle *handle)
592 {
593         struct fuse_conn *fc = get_fuse_conn_super(sb);
594         struct inode *inode;
595         struct dentry *entry;
596         int err = -ESTALE;
597
598         if (handle->nodeid == 0)
599                 goto out_err;
600
601         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
602         if (!inode) {
603                 struct fuse_entry_out outarg;
604                 struct qstr name;
605
606                 if (!fc->export_support)
607                         goto out_err;
608
609                 name.len = 1;
610                 name.name = ".";
611                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
612                                        &inode);
613                 if (err && err != -ENOENT)
614                         goto out_err;
615                 if (err || !inode) {
616                         err = -ESTALE;
617                         goto out_err;
618                 }
619                 err = -EIO;
620                 if (get_node_id(inode) != handle->nodeid)
621                         goto out_iput;
622         }
623         err = -ESTALE;
624         if (inode->i_generation != handle->generation)
625                 goto out_iput;
626
627         entry = d_obtain_alias(inode);
628         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
629                 entry->d_op = &fuse_dentry_operations;
630                 fuse_invalidate_entry_cache(entry);
631         }
632
633         return entry;
634
635  out_iput:
636         iput(inode);
637  out_err:
638         return ERR_PTR(err);
639 }
640
641 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
642                            int connectable)
643 {
644         struct inode *inode = dentry->d_inode;
645         bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
646         int len = encode_parent ? 6 : 3;
647         u64 nodeid;
648         u32 generation;
649
650         if (*max_len < len)
651                 return  255;
652
653         nodeid = get_fuse_inode(inode)->nodeid;
654         generation = inode->i_generation;
655
656         fh[0] = (u32)(nodeid >> 32);
657         fh[1] = (u32)(nodeid & 0xffffffff);
658         fh[2] = generation;
659
660         if (encode_parent) {
661                 struct inode *parent;
662
663                 spin_lock(&dentry->d_lock);
664                 parent = dentry->d_parent->d_inode;
665                 nodeid = get_fuse_inode(parent)->nodeid;
666                 generation = parent->i_generation;
667                 spin_unlock(&dentry->d_lock);
668
669                 fh[3] = (u32)(nodeid >> 32);
670                 fh[4] = (u32)(nodeid & 0xffffffff);
671                 fh[5] = generation;
672         }
673
674         *max_len = len;
675         return encode_parent ? 0x82 : 0x81;
676 }
677
678 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
679                 struct fid *fid, int fh_len, int fh_type)
680 {
681         struct fuse_inode_handle handle;
682
683         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
684                 return NULL;
685
686         handle.nodeid = (u64) fid->raw[0] << 32;
687         handle.nodeid |= (u64) fid->raw[1];
688         handle.generation = fid->raw[2];
689         return fuse_get_dentry(sb, &handle);
690 }
691
692 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
693                 struct fid *fid, int fh_len, int fh_type)
694 {
695         struct fuse_inode_handle parent;
696
697         if (fh_type != 0x82 || fh_len < 6)
698                 return NULL;
699
700         parent.nodeid = (u64) fid->raw[3] << 32;
701         parent.nodeid |= (u64) fid->raw[4];
702         parent.generation = fid->raw[5];
703         return fuse_get_dentry(sb, &parent);
704 }
705
706 static struct dentry *fuse_get_parent(struct dentry *child)
707 {
708         struct inode *child_inode = child->d_inode;
709         struct fuse_conn *fc = get_fuse_conn(child_inode);
710         struct inode *inode;
711         struct dentry *parent;
712         struct fuse_entry_out outarg;
713         struct qstr name;
714         int err;
715
716         if (!fc->export_support)
717                 return ERR_PTR(-ESTALE);
718
719         name.len = 2;
720         name.name = "..";
721         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
722                                &name, &outarg, &inode);
723         if (err) {
724                 if (err == -ENOENT)
725                         return ERR_PTR(-ESTALE);
726                 return ERR_PTR(err);
727         }
728
729         parent = d_obtain_alias(inode);
730         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
731                 parent->d_op = &fuse_dentry_operations;
732                 fuse_invalidate_entry_cache(parent);
733         }
734
735         return parent;
736 }
737
738 static const struct export_operations fuse_export_operations = {
739         .fh_to_dentry   = fuse_fh_to_dentry,
740         .fh_to_parent   = fuse_fh_to_parent,
741         .encode_fh      = fuse_encode_fh,
742         .get_parent     = fuse_get_parent,
743 };
744
745 static const struct super_operations fuse_super_operations = {
746         .alloc_inode    = fuse_alloc_inode,
747         .destroy_inode  = fuse_destroy_inode,
748         .clear_inode    = fuse_clear_inode,
749         .drop_inode     = generic_delete_inode,
750         .remount_fs     = fuse_remount_fs,
751         .put_super      = fuse_put_super,
752         .umount_begin   = fuse_umount_begin,
753         .statfs         = fuse_statfs,
754         .show_options   = fuse_show_options,
755 };
756
757 static void sanitize_global_limit(unsigned *limit)
758 {
759         if (*limit == 0)
760                 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
761                          sizeof(struct fuse_req);
762
763         if (*limit >= 1 << 16)
764                 *limit = (1 << 16) - 1;
765 }
766
767 static int set_global_limit(const char *val, struct kernel_param *kp)
768 {
769         int rv;
770
771         rv = param_set_uint(val, kp);
772         if (rv)
773                 return rv;
774
775         sanitize_global_limit((unsigned *)kp->arg);
776
777         return 0;
778 }
779
780 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
781 {
782         int cap_sys_admin = capable(CAP_SYS_ADMIN);
783
784         if (arg->minor < 13)
785                 return;
786
787         sanitize_global_limit(&max_user_bgreq);
788         sanitize_global_limit(&max_user_congthresh);
789
790         if (arg->max_background) {
791                 fc->max_background = arg->max_background;
792
793                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
794                         fc->max_background = max_user_bgreq;
795         }
796         if (arg->congestion_threshold) {
797                 fc->congestion_threshold = arg->congestion_threshold;
798
799                 if (!cap_sys_admin &&
800                     fc->congestion_threshold > max_user_congthresh)
801                         fc->congestion_threshold = max_user_congthresh;
802         }
803 }
804
805 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
806 {
807         struct fuse_init_out *arg = &req->misc.init_out;
808
809         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
810                 fc->conn_error = 1;
811         else {
812                 unsigned long ra_pages;
813
814                 process_init_limits(fc, arg);
815
816                 if (arg->minor >= 6) {
817                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
818                         if (arg->flags & FUSE_ASYNC_READ)
819                                 fc->async_read = 1;
820                         if (!(arg->flags & FUSE_POSIX_LOCKS))
821                                 fc->no_lock = 1;
822                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
823                                 fc->atomic_o_trunc = 1;
824                         if (arg->minor >= 9) {
825                                 /* LOOKUP has dependency on proto version */
826                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
827                                         fc->export_support = 1;
828                         }
829                         if (arg->flags & FUSE_BIG_WRITES)
830                                 fc->big_writes = 1;
831                         if (arg->flags & FUSE_DONT_MASK)
832                                 fc->dont_mask = 1;
833                 } else {
834                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
835                         fc->no_lock = 1;
836                 }
837
838                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
839                 fc->minor = arg->minor;
840                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
841                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
842                 fc->conn_init = 1;
843         }
844         fc->blocked = 0;
845         wake_up_all(&fc->blocked_waitq);
846 }
847
848 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
849 {
850         struct fuse_init_in *arg = &req->misc.init_in;
851
852         arg->major = FUSE_KERNEL_VERSION;
853         arg->minor = FUSE_KERNEL_MINOR_VERSION;
854         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
855         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
856                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK;
857         req->in.h.opcode = FUSE_INIT;
858         req->in.numargs = 1;
859         req->in.args[0].size = sizeof(*arg);
860         req->in.args[0].value = arg;
861         req->out.numargs = 1;
862         /* Variable length arguement used for backward compatibility
863            with interface version < 7.5.  Rest of init_out is zeroed
864            by do_get_request(), so a short reply is not a problem */
865         req->out.argvar = 1;
866         req->out.args[0].size = sizeof(struct fuse_init_out);
867         req->out.args[0].value = &req->misc.init_out;
868         req->end = process_init_reply;
869         fuse_request_send_background(fc, req);
870 }
871
872 static void fuse_free_conn(struct fuse_conn *fc)
873 {
874         kfree(fc);
875 }
876
877 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
878 {
879         int err;
880
881         fc->bdi.name = "fuse";
882         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
883         fc->bdi.unplug_io_fn = default_unplug_io_fn;
884         /* fuse does it's own writeback accounting */
885         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
886
887         err = bdi_init(&fc->bdi);
888         if (err)
889                 return err;
890
891         fc->bdi_initialized = 1;
892
893         if (sb->s_bdev) {
894                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
895                                     MAJOR(fc->dev), MINOR(fc->dev));
896         } else {
897                 err = bdi_register_dev(&fc->bdi, fc->dev);
898         }
899
900         if (err)
901                 return err;
902
903         /*
904          * For a single fuse filesystem use max 1% of dirty +
905          * writeback threshold.
906          *
907          * This gives about 1M of write buffer for memory maps on a
908          * machine with 1G and 10% dirty_ratio, which should be more
909          * than enough.
910          *
911          * Privileged users can raise it by writing to
912          *
913          *    /sys/class/bdi/<bdi>/max_ratio
914          */
915         bdi_set_max_ratio(&fc->bdi, 1);
916
917         return 0;
918 }
919
920 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
921 {
922         struct fuse_conn *fc;
923         struct inode *root;
924         struct fuse_mount_data d;
925         struct file *file;
926         struct dentry *root_dentry;
927         struct fuse_req *init_req;
928         int err;
929         int is_bdev = sb->s_bdev != NULL;
930
931         err = -EINVAL;
932         if (sb->s_flags & MS_MANDLOCK)
933                 goto err;
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
1001         init_req = fuse_request_alloc();
1002         if (!init_req)
1003                 goto err_put_root;
1004
1005         if (is_bdev) {
1006                 fc->destroy_req = fuse_request_alloc();
1007                 if (!fc->destroy_req)
1008                         goto err_free_init_req;
1009         }
1010
1011         mutex_lock(&fuse_mutex);
1012         err = -EINVAL;
1013         if (file->private_data)
1014                 goto err_unlock;
1015
1016         err = fuse_ctl_add_conn(fc);
1017         if (err)
1018                 goto err_unlock;
1019
1020         list_add_tail(&fc->entry, &fuse_conn_list);
1021         sb->s_root = root_dentry;
1022         fc->connected = 1;
1023         file->private_data = fuse_conn_get(fc);
1024         mutex_unlock(&fuse_mutex);
1025         /*
1026          * atomic_dec_and_test() in fput() provides the necessary
1027          * memory barrier for file->private_data to be visible on all
1028          * CPUs after this
1029          */
1030         fput(file);
1031
1032         fuse_send_init(fc, init_req);
1033
1034         return 0;
1035
1036  err_unlock:
1037         mutex_unlock(&fuse_mutex);
1038  err_free_init_req:
1039         fuse_request_free(init_req);
1040  err_put_root:
1041         dput(root_dentry);
1042  err_put_conn:
1043         fuse_bdi_destroy(fc);
1044         fuse_conn_put(fc);
1045  err_fput:
1046         fput(file);
1047  err:
1048         return err;
1049 }
1050
1051 static int fuse_get_sb(struct file_system_type *fs_type,
1052                        int flags, const char *dev_name,
1053                        void *raw_data, struct vfsmount *mnt)
1054 {
1055         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
1056 }
1057
1058 static void fuse_kill_sb_anon(struct super_block *sb)
1059 {
1060         struct fuse_conn *fc = get_fuse_conn_super(sb);
1061
1062         if (fc) {
1063                 down_write(&fc->killsb);
1064                 fc->sb = NULL;
1065                 up_write(&fc->killsb);
1066         }
1067
1068         kill_anon_super(sb);
1069 }
1070
1071 static struct file_system_type fuse_fs_type = {
1072         .owner          = THIS_MODULE,
1073         .name           = "fuse",
1074         .fs_flags       = FS_HAS_SUBTYPE,
1075         .get_sb         = fuse_get_sb,
1076         .kill_sb        = fuse_kill_sb_anon,
1077 };
1078
1079 #ifdef CONFIG_BLOCK
1080 static int fuse_get_sb_blk(struct file_system_type *fs_type,
1081                            int flags, const char *dev_name,
1082                            void *raw_data, struct vfsmount *mnt)
1083 {
1084         return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
1085                            mnt);
1086 }
1087
1088 static void fuse_kill_sb_blk(struct super_block *sb)
1089 {
1090         struct fuse_conn *fc = get_fuse_conn_super(sb);
1091
1092         if (fc) {
1093                 down_write(&fc->killsb);
1094                 fc->sb = NULL;
1095                 up_write(&fc->killsb);
1096         }
1097
1098         kill_block_super(sb);
1099 }
1100
1101 static struct file_system_type fuseblk_fs_type = {
1102         .owner          = THIS_MODULE,
1103         .name           = "fuseblk",
1104         .get_sb         = fuse_get_sb_blk,
1105         .kill_sb        = fuse_kill_sb_blk,
1106         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1107 };
1108
1109 static inline int register_fuseblk(void)
1110 {
1111         return register_filesystem(&fuseblk_fs_type);
1112 }
1113
1114 static inline void unregister_fuseblk(void)
1115 {
1116         unregister_filesystem(&fuseblk_fs_type);
1117 }
1118 #else
1119 static inline int register_fuseblk(void)
1120 {
1121         return 0;
1122 }
1123
1124 static inline void unregister_fuseblk(void)
1125 {
1126 }
1127 #endif
1128
1129 static void fuse_inode_init_once(void *foo)
1130 {
1131         struct inode *inode = foo;
1132
1133         inode_init_once(inode);
1134 }
1135
1136 static int __init fuse_fs_init(void)
1137 {
1138         int err;
1139
1140         err = register_filesystem(&fuse_fs_type);
1141         if (err)
1142                 goto out;
1143
1144         err = register_fuseblk();
1145         if (err)
1146                 goto out_unreg;
1147
1148         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1149                                               sizeof(struct fuse_inode),
1150                                               0, SLAB_HWCACHE_ALIGN,
1151                                               fuse_inode_init_once);
1152         err = -ENOMEM;
1153         if (!fuse_inode_cachep)
1154                 goto out_unreg2;
1155
1156         return 0;
1157
1158  out_unreg2:
1159         unregister_fuseblk();
1160  out_unreg:
1161         unregister_filesystem(&fuse_fs_type);
1162  out:
1163         return err;
1164 }
1165
1166 static void fuse_fs_cleanup(void)
1167 {
1168         unregister_filesystem(&fuse_fs_type);
1169         unregister_fuseblk();
1170         kmem_cache_destroy(fuse_inode_cachep);
1171 }
1172
1173 static struct kobject *fuse_kobj;
1174 static struct kobject *connections_kobj;
1175
1176 static int fuse_sysfs_init(void)
1177 {
1178         int err;
1179
1180         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1181         if (!fuse_kobj) {
1182                 err = -ENOMEM;
1183                 goto out_err;
1184         }
1185
1186         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1187         if (!connections_kobj) {
1188                 err = -ENOMEM;
1189                 goto out_fuse_unregister;
1190         }
1191
1192         return 0;
1193
1194  out_fuse_unregister:
1195         kobject_put(fuse_kobj);
1196  out_err:
1197         return err;
1198 }
1199
1200 static void fuse_sysfs_cleanup(void)
1201 {
1202         kobject_put(connections_kobj);
1203         kobject_put(fuse_kobj);
1204 }
1205
1206 static int __init fuse_init(void)
1207 {
1208         int res;
1209
1210         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1211                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1212
1213         INIT_LIST_HEAD(&fuse_conn_list);
1214         res = fuse_fs_init();
1215         if (res)
1216                 goto err;
1217
1218         res = fuse_dev_init();
1219         if (res)
1220                 goto err_fs_cleanup;
1221
1222         res = fuse_sysfs_init();
1223         if (res)
1224                 goto err_dev_cleanup;
1225
1226         res = fuse_ctl_init();
1227         if (res)
1228                 goto err_sysfs_cleanup;
1229
1230         sanitize_global_limit(&max_user_bgreq);
1231         sanitize_global_limit(&max_user_congthresh);
1232
1233         return 0;
1234
1235  err_sysfs_cleanup:
1236         fuse_sysfs_cleanup();
1237  err_dev_cleanup:
1238         fuse_dev_cleanup();
1239  err_fs_cleanup:
1240         fuse_fs_cleanup();
1241  err:
1242         return res;
1243 }
1244
1245 static void __exit fuse_exit(void)
1246 {
1247         printk(KERN_DEBUG "fuse exit\n");
1248
1249         fuse_ctl_cleanup();
1250         fuse_sysfs_cleanup();
1251         fuse_fs_cleanup();
1252         fuse_dev_cleanup();
1253 }
1254
1255 module_init(fuse_init);
1256 module_exit(fuse_exit);