b181e3441323e4bfc5aff8831055a3641b29a421
[linux-2.6.git] / net / sunrpc / rpc_pipe.c
1 /*
2  * net/sunrpc/rpc_pipe.c
3  *
4  * Userland/kernel interface for rpcauth_gss.
5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
6  * and fs/sysfs/inode.c
7  *
8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
9  *
10  */
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
14 #include <linux/pagemap.h>
15 #include <linux/mount.h>
16 #include <linux/namei.h>
17 #include <linux/fsnotify.h>
18 #include <linux/kernel.h>
19
20 #include <asm/ioctls.h>
21 #include <linux/fs.h>
22 #include <linux/poll.h>
23 #include <linux/wait.h>
24 #include <linux/seq_file.h>
25
26 #include <linux/sunrpc/clnt.h>
27 #include <linux/workqueue.h>
28 #include <linux/sunrpc/rpc_pipe_fs.h>
29 #include <linux/sunrpc/cache.h>
30
31 static struct vfsmount *rpc_mnt __read_mostly;
32 static int rpc_mount_count;
33
34 static struct file_system_type rpc_pipe_fs_type;
35
36
37 static struct kmem_cache *rpc_inode_cachep __read_mostly;
38
39 #define RPC_UPCALL_TIMEOUT (30*HZ)
40
41 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
42                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
43 {
44         struct rpc_pipe_msg *msg;
45
46         if (list_empty(head))
47                 return;
48         do {
49                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
50                 list_del_init(&msg->list);
51                 msg->errno = err;
52                 destroy_msg(msg);
53         } while (!list_empty(head));
54         wake_up(&rpci->waitq);
55 }
56
57 static void
58 rpc_timeout_upcall_queue(struct work_struct *work)
59 {
60         LIST_HEAD(free_list);
61         struct rpc_inode *rpci =
62                 container_of(work, struct rpc_inode, queue_timeout.work);
63         struct inode *inode = &rpci->vfs_inode;
64         void (*destroy_msg)(struct rpc_pipe_msg *);
65
66         spin_lock(&inode->i_lock);
67         if (rpci->ops == NULL) {
68                 spin_unlock(&inode->i_lock);
69                 return;
70         }
71         destroy_msg = rpci->ops->destroy_msg;
72         if (rpci->nreaders == 0) {
73                 list_splice_init(&rpci->pipe, &free_list);
74                 rpci->pipelen = 0;
75         }
76         spin_unlock(&inode->i_lock);
77         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
78 }
79
80 /**
81  * rpc_queue_upcall - queue an upcall message to userspace
82  * @inode: inode of upcall pipe on which to queue given message
83  * @msg: message to queue
84  *
85  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
86  * A userspace process may then later read the upcall by performing a
87  * read on an open file for this inode.  It is up to the caller to
88  * initialize the fields of @msg (other than @msg->list) appropriately.
89  */
90 int
91 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
92 {
93         struct rpc_inode *rpci = RPC_I(inode);
94         int res = -EPIPE;
95
96         spin_lock(&inode->i_lock);
97         if (rpci->ops == NULL)
98                 goto out;
99         if (rpci->nreaders) {
100                 list_add_tail(&msg->list, &rpci->pipe);
101                 rpci->pipelen += msg->len;
102                 res = 0;
103         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
104                 if (list_empty(&rpci->pipe))
105                         queue_delayed_work(rpciod_workqueue,
106                                         &rpci->queue_timeout,
107                                         RPC_UPCALL_TIMEOUT);
108                 list_add_tail(&msg->list, &rpci->pipe);
109                 rpci->pipelen += msg->len;
110                 res = 0;
111         }
112 out:
113         spin_unlock(&inode->i_lock);
114         wake_up(&rpci->waitq);
115         return res;
116 }
117 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
118
119 static inline void
120 rpc_inode_setowner(struct inode *inode, void *private)
121 {
122         RPC_I(inode)->private = private;
123 }
124
125 static void
126 rpc_close_pipes(struct inode *inode)
127 {
128         struct rpc_inode *rpci = RPC_I(inode);
129         const struct rpc_pipe_ops *ops;
130         int need_release;
131
132         mutex_lock(&inode->i_mutex);
133         ops = rpci->ops;
134         if (ops != NULL) {
135                 LIST_HEAD(free_list);
136                 spin_lock(&inode->i_lock);
137                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
138                 rpci->nreaders = 0;
139                 list_splice_init(&rpci->in_upcall, &free_list);
140                 list_splice_init(&rpci->pipe, &free_list);
141                 rpci->pipelen = 0;
142                 rpci->ops = NULL;
143                 spin_unlock(&inode->i_lock);
144                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
145                 rpci->nwriters = 0;
146                 if (need_release && ops->release_pipe)
147                         ops->release_pipe(inode);
148                 cancel_delayed_work_sync(&rpci->queue_timeout);
149         }
150         rpc_inode_setowner(inode, NULL);
151         mutex_unlock(&inode->i_mutex);
152 }
153
154 static struct inode *
155 rpc_alloc_inode(struct super_block *sb)
156 {
157         struct rpc_inode *rpci;
158         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
159         if (!rpci)
160                 return NULL;
161         return &rpci->vfs_inode;
162 }
163
164 static void
165 rpc_i_callback(struct rcu_head *head)
166 {
167         struct inode *inode = container_of(head, struct inode, i_rcu);
168         INIT_LIST_HEAD(&inode->i_dentry);
169         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
170 }
171
172 static void
173 rpc_destroy_inode(struct inode *inode)
174 {
175         call_rcu(&inode->i_rcu, rpc_i_callback);
176 }
177
178 static int
179 rpc_pipe_open(struct inode *inode, struct file *filp)
180 {
181         struct rpc_inode *rpci = RPC_I(inode);
182         int first_open;
183         int res = -ENXIO;
184
185         mutex_lock(&inode->i_mutex);
186         if (rpci->ops == NULL)
187                 goto out;
188         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
189         if (first_open && rpci->ops->open_pipe) {
190                 res = rpci->ops->open_pipe(inode);
191                 if (res)
192                         goto out;
193         }
194         if (filp->f_mode & FMODE_READ)
195                 rpci->nreaders++;
196         if (filp->f_mode & FMODE_WRITE)
197                 rpci->nwriters++;
198         res = 0;
199 out:
200         mutex_unlock(&inode->i_mutex);
201         return res;
202 }
203
204 static int
205 rpc_pipe_release(struct inode *inode, struct file *filp)
206 {
207         struct rpc_inode *rpci = RPC_I(inode);
208         struct rpc_pipe_msg *msg;
209         int last_close;
210
211         mutex_lock(&inode->i_mutex);
212         if (rpci->ops == NULL)
213                 goto out;
214         msg = filp->private_data;
215         if (msg != NULL) {
216                 spin_lock(&inode->i_lock);
217                 msg->errno = -EAGAIN;
218                 list_del_init(&msg->list);
219                 spin_unlock(&inode->i_lock);
220                 rpci->ops->destroy_msg(msg);
221         }
222         if (filp->f_mode & FMODE_WRITE)
223                 rpci->nwriters --;
224         if (filp->f_mode & FMODE_READ) {
225                 rpci->nreaders --;
226                 if (rpci->nreaders == 0) {
227                         LIST_HEAD(free_list);
228                         spin_lock(&inode->i_lock);
229                         list_splice_init(&rpci->pipe, &free_list);
230                         rpci->pipelen = 0;
231                         spin_unlock(&inode->i_lock);
232                         rpc_purge_list(rpci, &free_list,
233                                         rpci->ops->destroy_msg, -EAGAIN);
234                 }
235         }
236         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
237         if (last_close && rpci->ops->release_pipe)
238                 rpci->ops->release_pipe(inode);
239 out:
240         mutex_unlock(&inode->i_mutex);
241         return 0;
242 }
243
244 static ssize_t
245 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
246 {
247         struct inode *inode = filp->f_path.dentry->d_inode;
248         struct rpc_inode *rpci = RPC_I(inode);
249         struct rpc_pipe_msg *msg;
250         int res = 0;
251
252         mutex_lock(&inode->i_mutex);
253         if (rpci->ops == NULL) {
254                 res = -EPIPE;
255                 goto out_unlock;
256         }
257         msg = filp->private_data;
258         if (msg == NULL) {
259                 spin_lock(&inode->i_lock);
260                 if (!list_empty(&rpci->pipe)) {
261                         msg = list_entry(rpci->pipe.next,
262                                         struct rpc_pipe_msg,
263                                         list);
264                         list_move(&msg->list, &rpci->in_upcall);
265                         rpci->pipelen -= msg->len;
266                         filp->private_data = msg;
267                         msg->copied = 0;
268                 }
269                 spin_unlock(&inode->i_lock);
270                 if (msg == NULL)
271                         goto out_unlock;
272         }
273         /* NOTE: it is up to the callback to update msg->copied */
274         res = rpci->ops->upcall(filp, msg, buf, len);
275         if (res < 0 || msg->len == msg->copied) {
276                 filp->private_data = NULL;
277                 spin_lock(&inode->i_lock);
278                 list_del_init(&msg->list);
279                 spin_unlock(&inode->i_lock);
280                 rpci->ops->destroy_msg(msg);
281         }
282 out_unlock:
283         mutex_unlock(&inode->i_mutex);
284         return res;
285 }
286
287 static ssize_t
288 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
289 {
290         struct inode *inode = filp->f_path.dentry->d_inode;
291         struct rpc_inode *rpci = RPC_I(inode);
292         int res;
293
294         mutex_lock(&inode->i_mutex);
295         res = -EPIPE;
296         if (rpci->ops != NULL)
297                 res = rpci->ops->downcall(filp, buf, len);
298         mutex_unlock(&inode->i_mutex);
299         return res;
300 }
301
302 static unsigned int
303 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
304 {
305         struct rpc_inode *rpci;
306         unsigned int mask = 0;
307
308         rpci = RPC_I(filp->f_path.dentry->d_inode);
309         poll_wait(filp, &rpci->waitq, wait);
310
311         mask = POLLOUT | POLLWRNORM;
312         if (rpci->ops == NULL)
313                 mask |= POLLERR | POLLHUP;
314         if (filp->private_data || !list_empty(&rpci->pipe))
315                 mask |= POLLIN | POLLRDNORM;
316         return mask;
317 }
318
319 static long
320 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
321 {
322         struct inode *inode = filp->f_path.dentry->d_inode;
323         struct rpc_inode *rpci = RPC_I(inode);
324         int len;
325
326         switch (cmd) {
327         case FIONREAD:
328                 spin_lock(&inode->i_lock);
329                 if (rpci->ops == NULL) {
330                         spin_unlock(&inode->i_lock);
331                         return -EPIPE;
332                 }
333                 len = rpci->pipelen;
334                 if (filp->private_data) {
335                         struct rpc_pipe_msg *msg;
336                         msg = filp->private_data;
337                         len += msg->len - msg->copied;
338                 }
339                 spin_unlock(&inode->i_lock);
340                 return put_user(len, (int __user *)arg);
341         default:
342                 return -EINVAL;
343         }
344 }
345
346 static const struct file_operations rpc_pipe_fops = {
347         .owner          = THIS_MODULE,
348         .llseek         = no_llseek,
349         .read           = rpc_pipe_read,
350         .write          = rpc_pipe_write,
351         .poll           = rpc_pipe_poll,
352         .unlocked_ioctl = rpc_pipe_ioctl,
353         .open           = rpc_pipe_open,
354         .release        = rpc_pipe_release,
355 };
356
357 static int
358 rpc_show_info(struct seq_file *m, void *v)
359 {
360         struct rpc_clnt *clnt = m->private;
361
362         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
363         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
364                         clnt->cl_prog, clnt->cl_vers);
365         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
366         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
367         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
368         return 0;
369 }
370
371 static int
372 rpc_info_open(struct inode *inode, struct file *file)
373 {
374         struct rpc_clnt *clnt = NULL;
375         int ret = single_open(file, rpc_show_info, NULL);
376
377         if (!ret) {
378                 struct seq_file *m = file->private_data;
379
380                 spin_lock(&file->f_path.dentry->d_lock);
381                 if (!d_unhashed(file->f_path.dentry))
382                         clnt = RPC_I(inode)->private;
383                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
384                         spin_unlock(&file->f_path.dentry->d_lock);
385                         m->private = clnt;
386                 } else {
387                         spin_unlock(&file->f_path.dentry->d_lock);
388                         single_release(inode, file);
389                         ret = -EINVAL;
390                 }
391         }
392         return ret;
393 }
394
395 static int
396 rpc_info_release(struct inode *inode, struct file *file)
397 {
398         struct seq_file *m = file->private_data;
399         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
400
401         if (clnt)
402                 rpc_release_client(clnt);
403         return single_release(inode, file);
404 }
405
406 static const struct file_operations rpc_info_operations = {
407         .owner          = THIS_MODULE,
408         .open           = rpc_info_open,
409         .read           = seq_read,
410         .llseek         = seq_lseek,
411         .release        = rpc_info_release,
412 };
413
414
415 /*
416  * Description of fs contents.
417  */
418 struct rpc_filelist {
419         const char *name;
420         const struct file_operations *i_fop;
421         umode_t mode;
422 };
423
424 struct vfsmount *rpc_get_mount(void)
425 {
426         int err;
427
428         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count);
429         if (err != 0)
430                 return ERR_PTR(err);
431         return rpc_mnt;
432 }
433 EXPORT_SYMBOL_GPL(rpc_get_mount);
434
435 void rpc_put_mount(void)
436 {
437         simple_release_fs(&rpc_mnt, &rpc_mount_count);
438 }
439 EXPORT_SYMBOL_GPL(rpc_put_mount);
440
441 static int rpc_delete_dentry(const struct dentry *dentry)
442 {
443         return 1;
444 }
445
446 static const struct dentry_operations rpc_dentry_operations = {
447         .d_delete = rpc_delete_dentry,
448 };
449
450 static struct inode *
451 rpc_get_inode(struct super_block *sb, umode_t mode)
452 {
453         struct inode *inode = new_inode(sb);
454         if (!inode)
455                 return NULL;
456         inode->i_ino = get_next_ino();
457         inode->i_mode = mode;
458         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
459         switch (mode & S_IFMT) {
460         case S_IFDIR:
461                 inode->i_fop = &simple_dir_operations;
462                 inode->i_op = &simple_dir_inode_operations;
463                 inc_nlink(inode);
464         default:
465                 break;
466         }
467         return inode;
468 }
469
470 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
471                                umode_t mode,
472                                const struct file_operations *i_fop,
473                                void *private)
474 {
475         struct inode *inode;
476
477         d_drop(dentry);
478         inode = rpc_get_inode(dir->i_sb, mode);
479         if (!inode)
480                 goto out_err;
481         inode->i_ino = iunique(dir->i_sb, 100);
482         if (i_fop)
483                 inode->i_fop = i_fop;
484         if (private)
485                 rpc_inode_setowner(inode, private);
486         d_add(dentry, inode);
487         return 0;
488 out_err:
489         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
490                         __FILE__, __func__, dentry->d_name.name);
491         dput(dentry);
492         return -ENOMEM;
493 }
494
495 static int __rpc_create(struct inode *dir, struct dentry *dentry,
496                         umode_t mode,
497                         const struct file_operations *i_fop,
498                         void *private)
499 {
500         int err;
501
502         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
503         if (err)
504                 return err;
505         fsnotify_create(dir, dentry);
506         return 0;
507 }
508
509 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
510                        umode_t mode,
511                        const struct file_operations *i_fop,
512                        void *private)
513 {
514         int err;
515
516         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
517         if (err)
518                 return err;
519         inc_nlink(dir);
520         fsnotify_mkdir(dir, dentry);
521         return 0;
522 }
523
524 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
525                         umode_t mode,
526                         const struct file_operations *i_fop,
527                         void *private,
528                         const struct rpc_pipe_ops *ops,
529                         int flags)
530 {
531         struct rpc_inode *rpci;
532         int err;
533
534         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
535         if (err)
536                 return err;
537         rpci = RPC_I(dentry->d_inode);
538         rpci->nkern_readwriters = 1;
539         rpci->private = private;
540         rpci->flags = flags;
541         rpci->ops = ops;
542         fsnotify_create(dir, dentry);
543         return 0;
544 }
545
546 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
547 {
548         int ret;
549
550         dget(dentry);
551         ret = simple_rmdir(dir, dentry);
552         d_delete(dentry);
553         dput(dentry);
554         return ret;
555 }
556
557 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
558 {
559         int ret;
560
561         dget(dentry);
562         ret = simple_unlink(dir, dentry);
563         d_delete(dentry);
564         dput(dentry);
565         return ret;
566 }
567
568 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
569 {
570         struct inode *inode = dentry->d_inode;
571         struct rpc_inode *rpci = RPC_I(inode);
572
573         rpci->nkern_readwriters--;
574         if (rpci->nkern_readwriters != 0)
575                 return 0;
576         rpc_close_pipes(inode);
577         return __rpc_unlink(dir, dentry);
578 }
579
580 static struct dentry *__rpc_lookup_create(struct dentry *parent,
581                                           struct qstr *name)
582 {
583         struct dentry *dentry;
584
585         dentry = d_lookup(parent, name);
586         if (!dentry) {
587                 dentry = d_alloc(parent, name);
588                 if (!dentry) {
589                         dentry = ERR_PTR(-ENOMEM);
590                         goto out_err;
591                 }
592         }
593         if (!dentry->d_inode)
594                 d_set_d_op(dentry, &rpc_dentry_operations);
595 out_err:
596         return dentry;
597 }
598
599 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
600                                           struct qstr *name)
601 {
602         struct dentry *dentry;
603
604         dentry = __rpc_lookup_create(parent, name);
605         if (IS_ERR(dentry))
606                 return dentry;
607         if (dentry->d_inode == NULL)
608                 return dentry;
609         dput(dentry);
610         return ERR_PTR(-EEXIST);
611 }
612
613 /*
614  * FIXME: This probably has races.
615  */
616 static void __rpc_depopulate(struct dentry *parent,
617                              const struct rpc_filelist *files,
618                              int start, int eof)
619 {
620         struct inode *dir = parent->d_inode;
621         struct dentry *dentry;
622         struct qstr name;
623         int i;
624
625         for (i = start; i < eof; i++) {
626                 name.name = files[i].name;
627                 name.len = strlen(files[i].name);
628                 name.hash = full_name_hash(name.name, name.len);
629                 dentry = d_lookup(parent, &name);
630
631                 if (dentry == NULL)
632                         continue;
633                 if (dentry->d_inode == NULL)
634                         goto next;
635                 switch (dentry->d_inode->i_mode & S_IFMT) {
636                         default:
637                                 BUG();
638                         case S_IFREG:
639                                 __rpc_unlink(dir, dentry);
640                                 break;
641                         case S_IFDIR:
642                                 __rpc_rmdir(dir, dentry);
643                 }
644 next:
645                 dput(dentry);
646         }
647 }
648
649 static void rpc_depopulate(struct dentry *parent,
650                            const struct rpc_filelist *files,
651                            int start, int eof)
652 {
653         struct inode *dir = parent->d_inode;
654
655         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
656         __rpc_depopulate(parent, files, start, eof);
657         mutex_unlock(&dir->i_mutex);
658 }
659
660 static int rpc_populate(struct dentry *parent,
661                         const struct rpc_filelist *files,
662                         int start, int eof,
663                         void *private)
664 {
665         struct inode *dir = parent->d_inode;
666         struct dentry *dentry;
667         int i, err;
668
669         mutex_lock(&dir->i_mutex);
670         for (i = start; i < eof; i++) {
671                 struct qstr q;
672
673                 q.name = files[i].name;
674                 q.len = strlen(files[i].name);
675                 q.hash = full_name_hash(q.name, q.len);
676                 dentry = __rpc_lookup_create_exclusive(parent, &q);
677                 err = PTR_ERR(dentry);
678                 if (IS_ERR(dentry))
679                         goto out_bad;
680                 switch (files[i].mode & S_IFMT) {
681                         default:
682                                 BUG();
683                         case S_IFREG:
684                                 err = __rpc_create(dir, dentry,
685                                                 files[i].mode,
686                                                 files[i].i_fop,
687                                                 private);
688                                 break;
689                         case S_IFDIR:
690                                 err = __rpc_mkdir(dir, dentry,
691                                                 files[i].mode,
692                                                 NULL,
693                                                 private);
694                 }
695                 if (err != 0)
696                         goto out_bad;
697         }
698         mutex_unlock(&dir->i_mutex);
699         return 0;
700 out_bad:
701         __rpc_depopulate(parent, files, start, eof);
702         mutex_unlock(&dir->i_mutex);
703         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
704                         __FILE__, __func__, parent->d_name.name);
705         return err;
706 }
707
708 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
709                 struct qstr *name, umode_t mode, void *private,
710                 int (*populate)(struct dentry *, void *), void *args_populate)
711 {
712         struct dentry *dentry;
713         struct inode *dir = parent->d_inode;
714         int error;
715
716         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
717         dentry = __rpc_lookup_create_exclusive(parent, name);
718         if (IS_ERR(dentry))
719                 goto out;
720         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
721         if (error != 0)
722                 goto out_err;
723         if (populate != NULL) {
724                 error = populate(dentry, args_populate);
725                 if (error)
726                         goto err_rmdir;
727         }
728 out:
729         mutex_unlock(&dir->i_mutex);
730         return dentry;
731 err_rmdir:
732         __rpc_rmdir(dir, dentry);
733 out_err:
734         dentry = ERR_PTR(error);
735         goto out;
736 }
737
738 static int rpc_rmdir_depopulate(struct dentry *dentry,
739                 void (*depopulate)(struct dentry *))
740 {
741         struct dentry *parent;
742         struct inode *dir;
743         int error;
744
745         parent = dget_parent(dentry);
746         dir = parent->d_inode;
747         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
748         if (depopulate != NULL)
749                 depopulate(dentry);
750         error = __rpc_rmdir(dir, dentry);
751         mutex_unlock(&dir->i_mutex);
752         dput(parent);
753         return error;
754 }
755
756 /**
757  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
758  * @parent: dentry of directory to create new "pipe" in
759  * @name: name of pipe
760  * @private: private data to associate with the pipe, for the caller's use
761  * @ops: operations defining the behavior of the pipe: upcall, downcall,
762  *      release_pipe, open_pipe, and destroy_msg.
763  * @flags: rpc_inode flags
764  *
765  * Data is made available for userspace to read by calls to
766  * rpc_queue_upcall().  The actual reads will result in calls to
767  * @ops->upcall, which will be called with the file pointer,
768  * message, and userspace buffer to copy to.
769  *
770  * Writes can come at any time, and do not necessarily have to be
771  * responses to upcalls.  They will result in calls to @msg->downcall.
772  *
773  * The @private argument passed here will be available to all these methods
774  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
775  */
776 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
777                           void *private, const struct rpc_pipe_ops *ops,
778                           int flags)
779 {
780         struct dentry *dentry;
781         struct inode *dir = parent->d_inode;
782         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
783         struct qstr q;
784         int err;
785
786         if (ops->upcall == NULL)
787                 umode &= ~S_IRUGO;
788         if (ops->downcall == NULL)
789                 umode &= ~S_IWUGO;
790
791         q.name = name;
792         q.len = strlen(name);
793         q.hash = full_name_hash(q.name, q.len),
794
795         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
796         dentry = __rpc_lookup_create(parent, &q);
797         if (IS_ERR(dentry))
798                 goto out;
799         if (dentry->d_inode) {
800                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
801                 if (rpci->private != private ||
802                                 rpci->ops != ops ||
803                                 rpci->flags != flags) {
804                         dput (dentry);
805                         err = -EBUSY;
806                         goto out_err;
807                 }
808                 rpci->nkern_readwriters++;
809                 goto out;
810         }
811
812         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
813                            private, ops, flags);
814         if (err)
815                 goto out_err;
816 out:
817         mutex_unlock(&dir->i_mutex);
818         return dentry;
819 out_err:
820         dentry = ERR_PTR(err);
821         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
822                         __FILE__, __func__, parent->d_name.name, name,
823                         err);
824         goto out;
825 }
826 EXPORT_SYMBOL_GPL(rpc_mkpipe);
827
828 /**
829  * rpc_unlink - remove a pipe
830  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
831  *
832  * After this call, lookups will no longer find the pipe, and any
833  * attempts to read or write using preexisting opens of the pipe will
834  * return -EPIPE.
835  */
836 int
837 rpc_unlink(struct dentry *dentry)
838 {
839         struct dentry *parent;
840         struct inode *dir;
841         int error = 0;
842
843         parent = dget_parent(dentry);
844         dir = parent->d_inode;
845         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
846         error = __rpc_rmpipe(dir, dentry);
847         mutex_unlock(&dir->i_mutex);
848         dput(parent);
849         return error;
850 }
851 EXPORT_SYMBOL_GPL(rpc_unlink);
852
853 enum {
854         RPCAUTH_info,
855         RPCAUTH_EOF
856 };
857
858 static const struct rpc_filelist authfiles[] = {
859         [RPCAUTH_info] = {
860                 .name = "info",
861                 .i_fop = &rpc_info_operations,
862                 .mode = S_IFREG | S_IRUSR,
863         },
864 };
865
866 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
867 {
868         return rpc_populate(dentry,
869                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
870                             private);
871 }
872
873 static void rpc_clntdir_depopulate(struct dentry *dentry)
874 {
875         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
876 }
877
878 /**
879  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
880  * @dentry: dentry from the rpc_pipefs root to the new directory
881  * @name: &struct qstr for the name
882  * @rpc_client: rpc client to associate with this directory
883  *
884  * This creates a directory at the given @path associated with
885  * @rpc_clnt, which will contain a file named "info" with some basic
886  * information about the client, together with any "pipes" that may
887  * later be created using rpc_mkpipe().
888  */
889 struct dentry *rpc_create_client_dir(struct dentry *dentry,
890                                    struct qstr *name,
891                                    struct rpc_clnt *rpc_client)
892 {
893         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
894                         rpc_clntdir_populate, rpc_client);
895 }
896
897 /**
898  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
899  * @dentry: directory to remove
900  */
901 int rpc_remove_client_dir(struct dentry *dentry)
902 {
903         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
904 }
905
906 static const struct rpc_filelist cache_pipefs_files[3] = {
907         [0] = {
908                 .name = "channel",
909                 .i_fop = &cache_file_operations_pipefs,
910                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
911         },
912         [1] = {
913                 .name = "content",
914                 .i_fop = &content_file_operations_pipefs,
915                 .mode = S_IFREG|S_IRUSR,
916         },
917         [2] = {
918                 .name = "flush",
919                 .i_fop = &cache_flush_operations_pipefs,
920                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
921         },
922 };
923
924 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
925 {
926         return rpc_populate(dentry,
927                             cache_pipefs_files, 0, 3,
928                             private);
929 }
930
931 static void rpc_cachedir_depopulate(struct dentry *dentry)
932 {
933         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
934 }
935
936 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
937                                     mode_t umode, struct cache_detail *cd)
938 {
939         return rpc_mkdir_populate(parent, name, umode, NULL,
940                         rpc_cachedir_populate, cd);
941 }
942
943 void rpc_remove_cache_dir(struct dentry *dentry)
944 {
945         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
946 }
947
948 /*
949  * populate the filesystem
950  */
951 static const struct super_operations s_ops = {
952         .alloc_inode    = rpc_alloc_inode,
953         .destroy_inode  = rpc_destroy_inode,
954         .statfs         = simple_statfs,
955 };
956
957 #define RPCAUTH_GSSMAGIC 0x67596969
958
959 /*
960  * We have a single directory with 1 node in it.
961  */
962 enum {
963         RPCAUTH_lockd,
964         RPCAUTH_mount,
965         RPCAUTH_nfs,
966         RPCAUTH_portmap,
967         RPCAUTH_statd,
968         RPCAUTH_nfsd4_cb,
969         RPCAUTH_cache,
970         RPCAUTH_RootEOF
971 };
972
973 static const struct rpc_filelist files[] = {
974         [RPCAUTH_lockd] = {
975                 .name = "lockd",
976                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
977         },
978         [RPCAUTH_mount] = {
979                 .name = "mount",
980                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
981         },
982         [RPCAUTH_nfs] = {
983                 .name = "nfs",
984                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
985         },
986         [RPCAUTH_portmap] = {
987                 .name = "portmap",
988                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
989         },
990         [RPCAUTH_statd] = {
991                 .name = "statd",
992                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
993         },
994         [RPCAUTH_nfsd4_cb] = {
995                 .name = "nfsd4_cb",
996                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
997         },
998         [RPCAUTH_cache] = {
999                 .name = "cache",
1000                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1001         },
1002 };
1003
1004 static int
1005 rpc_fill_super(struct super_block *sb, void *data, int silent)
1006 {
1007         struct inode *inode;
1008         struct dentry *root;
1009
1010         sb->s_blocksize = PAGE_CACHE_SIZE;
1011         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1012         sb->s_magic = RPCAUTH_GSSMAGIC;
1013         sb->s_op = &s_ops;
1014         sb->s_time_gran = 1;
1015
1016         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1017         if (!inode)
1018                 return -ENOMEM;
1019         sb->s_root = root = d_alloc_root(inode);
1020         if (!root) {
1021                 iput(inode);
1022                 return -ENOMEM;
1023         }
1024         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1025                 return -ENOMEM;
1026         return 0;
1027 }
1028
1029 static struct dentry *
1030 rpc_mount(struct file_system_type *fs_type,
1031                 int flags, const char *dev_name, void *data)
1032 {
1033         return mount_single(fs_type, flags, data, rpc_fill_super);
1034 }
1035
1036 static struct file_system_type rpc_pipe_fs_type = {
1037         .owner          = THIS_MODULE,
1038         .name           = "rpc_pipefs",
1039         .mount          = rpc_mount,
1040         .kill_sb        = kill_litter_super,
1041 };
1042
1043 static void
1044 init_once(void *foo)
1045 {
1046         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1047
1048         inode_init_once(&rpci->vfs_inode);
1049         rpci->private = NULL;
1050         rpci->nreaders = 0;
1051         rpci->nwriters = 0;
1052         INIT_LIST_HEAD(&rpci->in_upcall);
1053         INIT_LIST_HEAD(&rpci->in_downcall);
1054         INIT_LIST_HEAD(&rpci->pipe);
1055         rpci->pipelen = 0;
1056         init_waitqueue_head(&rpci->waitq);
1057         INIT_DELAYED_WORK(&rpci->queue_timeout,
1058                             rpc_timeout_upcall_queue);
1059         rpci->ops = NULL;
1060 }
1061
1062 int register_rpc_pipefs(void)
1063 {
1064         int err;
1065
1066         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1067                                 sizeof(struct rpc_inode),
1068                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1069                                                 SLAB_MEM_SPREAD),
1070                                 init_once);
1071         if (!rpc_inode_cachep)
1072                 return -ENOMEM;
1073         err = register_filesystem(&rpc_pipe_fs_type);
1074         if (err) {
1075                 kmem_cache_destroy(rpc_inode_cachep);
1076                 return err;
1077         }
1078
1079         return 0;
1080 }
1081
1082 void unregister_rpc_pipefs(void)
1083 {
1084         kmem_cache_destroy(rpc_inode_cachep);
1085         unregister_filesystem(&rpc_pipe_fs_type);
1086 }