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