sunrpc: remove the big kernel lock
[linux-3.10.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 long
312 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
313 {
314         struct inode *inode = filp->f_path.dentry->d_inode;
315         struct rpc_inode *rpci = RPC_I(inode);
316         int len;
317
318         switch (cmd) {
319         case FIONREAD:
320                 spin_lock(&inode->i_lock);
321                 if (rpci->ops == NULL) {
322                         spin_unlock(&inode->i_lock);
323                         return -EPIPE;
324                 }
325                 len = rpci->pipelen;
326                 if (filp->private_data) {
327                         struct rpc_pipe_msg *msg;
328                         msg = (struct rpc_pipe_msg *)filp->private_data;
329                         len += msg->len - msg->copied;
330                 }
331                 spin_unlock(&inode->i_lock);
332                 return put_user(len, (int __user *)arg);
333         default:
334                 return -EINVAL;
335         }
336 }
337
338 static const struct file_operations rpc_pipe_fops = {
339         .owner          = THIS_MODULE,
340         .llseek         = no_llseek,
341         .read           = rpc_pipe_read,
342         .write          = rpc_pipe_write,
343         .poll           = rpc_pipe_poll,
344         .unlocked_ioctl = rpc_pipe_ioctl,
345         .open           = rpc_pipe_open,
346         .release        = rpc_pipe_release,
347 };
348
349 static int
350 rpc_show_info(struct seq_file *m, void *v)
351 {
352         struct rpc_clnt *clnt = m->private;
353
354         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
355         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
356                         clnt->cl_prog, clnt->cl_vers);
357         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
358         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
359         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
360         return 0;
361 }
362
363 static int
364 rpc_info_open(struct inode *inode, struct file *file)
365 {
366         struct rpc_clnt *clnt;
367         int ret = single_open(file, rpc_show_info, NULL);
368
369         if (!ret) {
370                 struct seq_file *m = file->private_data;
371                 mutex_lock(&inode->i_mutex);
372                 clnt = RPC_I(inode)->private;
373                 if (clnt) {
374                         kref_get(&clnt->cl_kref);
375                         m->private = clnt;
376                 } else {
377                         single_release(inode, file);
378                         ret = -EINVAL;
379                 }
380                 mutex_unlock(&inode->i_mutex);
381         }
382         return ret;
383 }
384
385 static int
386 rpc_info_release(struct inode *inode, struct file *file)
387 {
388         struct seq_file *m = file->private_data;
389         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
390
391         if (clnt)
392                 rpc_release_client(clnt);
393         return single_release(inode, file);
394 }
395
396 static const struct file_operations rpc_info_operations = {
397         .owner          = THIS_MODULE,
398         .open           = rpc_info_open,
399         .read           = seq_read,
400         .llseek         = seq_lseek,
401         .release        = rpc_info_release,
402 };
403
404
405 /*
406  * Description of fs contents.
407  */
408 struct rpc_filelist {
409         const char *name;
410         const struct file_operations *i_fop;
411         umode_t mode;
412 };
413
414 struct vfsmount *rpc_get_mount(void)
415 {
416         int err;
417
418         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
419         if (err != 0)
420                 return ERR_PTR(err);
421         return rpc_mount;
422 }
423 EXPORT_SYMBOL_GPL(rpc_get_mount);
424
425 void rpc_put_mount(void)
426 {
427         simple_release_fs(&rpc_mount, &rpc_mount_count);
428 }
429 EXPORT_SYMBOL_GPL(rpc_put_mount);
430
431 static int rpc_delete_dentry(struct dentry *dentry)
432 {
433         return 1;
434 }
435
436 static const struct dentry_operations rpc_dentry_operations = {
437         .d_delete = rpc_delete_dentry,
438 };
439
440 static struct inode *
441 rpc_get_inode(struct super_block *sb, umode_t mode)
442 {
443         struct inode *inode = new_inode(sb);
444         if (!inode)
445                 return NULL;
446         inode->i_mode = mode;
447         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
448         switch(mode & S_IFMT) {
449                 case S_IFDIR:
450                         inode->i_fop = &simple_dir_operations;
451                         inode->i_op = &simple_dir_inode_operations;
452                         inc_nlink(inode);
453                 default:
454                         break;
455         }
456         return inode;
457 }
458
459 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
460                                umode_t mode,
461                                const struct file_operations *i_fop,
462                                void *private)
463 {
464         struct inode *inode;
465
466         BUG_ON(!d_unhashed(dentry));
467         inode = rpc_get_inode(dir->i_sb, mode);
468         if (!inode)
469                 goto out_err;
470         inode->i_ino = iunique(dir->i_sb, 100);
471         if (i_fop)
472                 inode->i_fop = i_fop;
473         if (private)
474                 rpc_inode_setowner(inode, private);
475         d_add(dentry, inode);
476         return 0;
477 out_err:
478         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
479                         __FILE__, __func__, dentry->d_name.name);
480         dput(dentry);
481         return -ENOMEM;
482 }
483
484 static int __rpc_create(struct inode *dir, struct dentry *dentry,
485                         umode_t mode,
486                         const struct file_operations *i_fop,
487                         void *private)
488 {
489         int err;
490
491         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
492         if (err)
493                 return err;
494         fsnotify_create(dir, dentry);
495         return 0;
496 }
497
498 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
499                        umode_t mode,
500                        const struct file_operations *i_fop,
501                        void *private)
502 {
503         int err;
504
505         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
506         if (err)
507                 return err;
508         inc_nlink(dir);
509         fsnotify_mkdir(dir, dentry);
510         return 0;
511 }
512
513 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
514                         umode_t mode,
515                         const struct file_operations *i_fop,
516                         void *private,
517                         const struct rpc_pipe_ops *ops,
518                         int flags)
519 {
520         struct rpc_inode *rpci;
521         int err;
522
523         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
524         if (err)
525                 return err;
526         rpci = RPC_I(dentry->d_inode);
527         rpci->nkern_readwriters = 1;
528         rpci->private = private;
529         rpci->flags = flags;
530         rpci->ops = ops;
531         fsnotify_create(dir, dentry);
532         return 0;
533 }
534
535 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
536 {
537         int ret;
538
539         dget(dentry);
540         ret = simple_rmdir(dir, dentry);
541         d_delete(dentry);
542         dput(dentry);
543         return ret;
544 }
545
546 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
547 {
548         int ret;
549
550         dget(dentry);
551         ret = simple_unlink(dir, dentry);
552         d_delete(dentry);
553         dput(dentry);
554         return ret;
555 }
556
557 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
558 {
559         struct inode *inode = dentry->d_inode;
560         struct rpc_inode *rpci = RPC_I(inode);
561
562         rpci->nkern_readwriters--;
563         if (rpci->nkern_readwriters != 0)
564                 return 0;
565         rpc_close_pipes(inode);
566         return __rpc_unlink(dir, dentry);
567 }
568
569 static struct dentry *__rpc_lookup_create(struct dentry *parent,
570                                           struct qstr *name)
571 {
572         struct dentry *dentry;
573
574         dentry = d_lookup(parent, name);
575         if (!dentry) {
576                 dentry = d_alloc(parent, name);
577                 if (!dentry) {
578                         dentry = ERR_PTR(-ENOMEM);
579                         goto out_err;
580                 }
581         }
582         if (!dentry->d_inode)
583                 dentry->d_op = &rpc_dentry_operations;
584 out_err:
585         return dentry;
586 }
587
588 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
589                                           struct qstr *name)
590 {
591         struct dentry *dentry;
592
593         dentry = __rpc_lookup_create(parent, name);
594         if (IS_ERR(dentry))
595                 return dentry;
596         if (dentry->d_inode == NULL)
597                 return dentry;
598         dput(dentry);
599         return ERR_PTR(-EEXIST);
600 }
601
602 /*
603  * FIXME: This probably has races.
604  */
605 static void __rpc_depopulate(struct dentry *parent,
606                              const struct rpc_filelist *files,
607                              int start, int eof)
608 {
609         struct inode *dir = parent->d_inode;
610         struct dentry *dentry;
611         struct qstr name;
612         int i;
613
614         for (i = start; i < eof; i++) {
615                 name.name = files[i].name;
616                 name.len = strlen(files[i].name);
617                 name.hash = full_name_hash(name.name, name.len);
618                 dentry = d_lookup(parent, &name);
619
620                 if (dentry == NULL)
621                         continue;
622                 if (dentry->d_inode == NULL)
623                         goto next;
624                 switch (dentry->d_inode->i_mode & S_IFMT) {
625                         default:
626                                 BUG();
627                         case S_IFREG:
628                                 __rpc_unlink(dir, dentry);
629                                 break;
630                         case S_IFDIR:
631                                 __rpc_rmdir(dir, dentry);
632                 }
633 next:
634                 dput(dentry);
635         }
636 }
637
638 static void rpc_depopulate(struct dentry *parent,
639                            const struct rpc_filelist *files,
640                            int start, int eof)
641 {
642         struct inode *dir = parent->d_inode;
643
644         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
645         __rpc_depopulate(parent, files, start, eof);
646         mutex_unlock(&dir->i_mutex);
647 }
648
649 static int rpc_populate(struct dentry *parent,
650                         const struct rpc_filelist *files,
651                         int start, int eof,
652                         void *private)
653 {
654         struct inode *dir = parent->d_inode;
655         struct dentry *dentry;
656         int i, err;
657
658         mutex_lock(&dir->i_mutex);
659         for (i = start; i < eof; i++) {
660                 struct qstr q;
661
662                 q.name = files[i].name;
663                 q.len = strlen(files[i].name);
664                 q.hash = full_name_hash(q.name, q.len);
665                 dentry = __rpc_lookup_create_exclusive(parent, &q);
666                 err = PTR_ERR(dentry);
667                 if (IS_ERR(dentry))
668                         goto out_bad;
669                 switch (files[i].mode & S_IFMT) {
670                         default:
671                                 BUG();
672                         case S_IFREG:
673                                 err = __rpc_create(dir, dentry,
674                                                 files[i].mode,
675                                                 files[i].i_fop,
676                                                 private);
677                                 break;
678                         case S_IFDIR:
679                                 err = __rpc_mkdir(dir, dentry,
680                                                 files[i].mode,
681                                                 NULL,
682                                                 private);
683                 }
684                 if (err != 0)
685                         goto out_bad;
686         }
687         mutex_unlock(&dir->i_mutex);
688         return 0;
689 out_bad:
690         __rpc_depopulate(parent, files, start, eof);
691         mutex_unlock(&dir->i_mutex);
692         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
693                         __FILE__, __func__, parent->d_name.name);
694         return err;
695 }
696
697 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
698                 struct qstr *name, umode_t mode, void *private,
699                 int (*populate)(struct dentry *, void *), void *args_populate)
700 {
701         struct dentry *dentry;
702         struct inode *dir = parent->d_inode;
703         int error;
704
705         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
706         dentry = __rpc_lookup_create_exclusive(parent, name);
707         if (IS_ERR(dentry))
708                 goto out;
709         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
710         if (error != 0)
711                 goto out_err;
712         if (populate != NULL) {
713                 error = populate(dentry, args_populate);
714                 if (error)
715                         goto err_rmdir;
716         }
717 out:
718         mutex_unlock(&dir->i_mutex);
719         return dentry;
720 err_rmdir:
721         __rpc_rmdir(dir, dentry);
722 out_err:
723         dentry = ERR_PTR(error);
724         goto out;
725 }
726
727 static int rpc_rmdir_depopulate(struct dentry *dentry,
728                 void (*depopulate)(struct dentry *))
729 {
730         struct dentry *parent;
731         struct inode *dir;
732         int error;
733
734         parent = dget_parent(dentry);
735         dir = parent->d_inode;
736         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
737         if (depopulate != NULL)
738                 depopulate(dentry);
739         error = __rpc_rmdir(dir, dentry);
740         mutex_unlock(&dir->i_mutex);
741         dput(parent);
742         return error;
743 }
744
745 /**
746  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
747  * @parent: dentry of directory to create new "pipe" in
748  * @name: name of pipe
749  * @private: private data to associate with the pipe, for the caller's use
750  * @ops: operations defining the behavior of the pipe: upcall, downcall,
751  *      release_pipe, open_pipe, and destroy_msg.
752  * @flags: rpc_inode flags
753  *
754  * Data is made available for userspace to read by calls to
755  * rpc_queue_upcall().  The actual reads will result in calls to
756  * @ops->upcall, which will be called with the file pointer,
757  * message, and userspace buffer to copy to.
758  *
759  * Writes can come at any time, and do not necessarily have to be
760  * responses to upcalls.  They will result in calls to @msg->downcall.
761  *
762  * The @private argument passed here will be available to all these methods
763  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
764  */
765 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
766                           void *private, const struct rpc_pipe_ops *ops,
767                           int flags)
768 {
769         struct dentry *dentry;
770         struct inode *dir = parent->d_inode;
771         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
772         struct qstr q;
773         int err;
774
775         if (ops->upcall == NULL)
776                 umode &= ~S_IRUGO;
777         if (ops->downcall == NULL)
778                 umode &= ~S_IWUGO;
779
780         q.name = name;
781         q.len = strlen(name);
782         q.hash = full_name_hash(q.name, q.len),
783
784         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
785         dentry = __rpc_lookup_create(parent, &q);
786         if (IS_ERR(dentry))
787                 goto out;
788         if (dentry->d_inode) {
789                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
790                 if (rpci->private != private ||
791                                 rpci->ops != ops ||
792                                 rpci->flags != flags) {
793                         dput (dentry);
794                         err = -EBUSY;
795                         goto out_err;
796                 }
797                 rpci->nkern_readwriters++;
798                 goto out;
799         }
800
801         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
802                            private, ops, flags);
803         if (err)
804                 goto out_err;
805 out:
806         mutex_unlock(&dir->i_mutex);
807         return dentry;
808 out_err:
809         dentry = ERR_PTR(err);
810         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
811                         __FILE__, __func__, parent->d_name.name, name,
812                         err);
813         goto out;
814 }
815 EXPORT_SYMBOL_GPL(rpc_mkpipe);
816
817 /**
818  * rpc_unlink - remove a pipe
819  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
820  *
821  * After this call, lookups will no longer find the pipe, and any
822  * attempts to read or write using preexisting opens of the pipe will
823  * return -EPIPE.
824  */
825 int
826 rpc_unlink(struct dentry *dentry)
827 {
828         struct dentry *parent;
829         struct inode *dir;
830         int error = 0;
831
832         parent = dget_parent(dentry);
833         dir = parent->d_inode;
834         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
835         error = __rpc_rmpipe(dir, dentry);
836         mutex_unlock(&dir->i_mutex);
837         dput(parent);
838         return error;
839 }
840 EXPORT_SYMBOL_GPL(rpc_unlink);
841
842 enum {
843         RPCAUTH_info,
844         RPCAUTH_EOF
845 };
846
847 static const struct rpc_filelist authfiles[] = {
848         [RPCAUTH_info] = {
849                 .name = "info",
850                 .i_fop = &rpc_info_operations,
851                 .mode = S_IFREG | S_IRUSR,
852         },
853 };
854
855 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
856 {
857         return rpc_populate(dentry,
858                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
859                             private);
860 }
861
862 static void rpc_clntdir_depopulate(struct dentry *dentry)
863 {
864         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
865 }
866
867 /**
868  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
869  * @dentry: dentry from the rpc_pipefs root to the new directory
870  * @name: &struct qstr for the name
871  * @rpc_client: rpc client to associate with this directory
872  *
873  * This creates a directory at the given @path associated with
874  * @rpc_clnt, which will contain a file named "info" with some basic
875  * information about the client, together with any "pipes" that may
876  * later be created using rpc_mkpipe().
877  */
878 struct dentry *rpc_create_client_dir(struct dentry *dentry,
879                                    struct qstr *name,
880                                    struct rpc_clnt *rpc_client)
881 {
882         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
883                         rpc_clntdir_populate, rpc_client);
884 }
885
886 /**
887  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
888  * @dentry: directory to remove
889  */
890 int rpc_remove_client_dir(struct dentry *dentry)
891 {
892         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
893 }
894
895 static const struct rpc_filelist cache_pipefs_files[3] = {
896         [0] = {
897                 .name = "channel",
898                 .i_fop = &cache_file_operations_pipefs,
899                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
900         },
901         [1] = {
902                 .name = "content",
903                 .i_fop = &content_file_operations_pipefs,
904                 .mode = S_IFREG|S_IRUSR,
905         },
906         [2] = {
907                 .name = "flush",
908                 .i_fop = &cache_flush_operations_pipefs,
909                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
910         },
911 };
912
913 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
914 {
915         return rpc_populate(dentry,
916                             cache_pipefs_files, 0, 3,
917                             private);
918 }
919
920 static void rpc_cachedir_depopulate(struct dentry *dentry)
921 {
922         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
923 }
924
925 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
926                                     mode_t umode, struct cache_detail *cd)
927 {
928         return rpc_mkdir_populate(parent, name, umode, NULL,
929                         rpc_cachedir_populate, cd);
930 }
931
932 void rpc_remove_cache_dir(struct dentry *dentry)
933 {
934         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
935 }
936
937 /*
938  * populate the filesystem
939  */
940 static const struct super_operations s_ops = {
941         .alloc_inode    = rpc_alloc_inode,
942         .destroy_inode  = rpc_destroy_inode,
943         .statfs         = simple_statfs,
944 };
945
946 #define RPCAUTH_GSSMAGIC 0x67596969
947
948 /*
949  * We have a single directory with 1 node in it.
950  */
951 enum {
952         RPCAUTH_lockd,
953         RPCAUTH_mount,
954         RPCAUTH_nfs,
955         RPCAUTH_portmap,
956         RPCAUTH_statd,
957         RPCAUTH_nfsd4_cb,
958         RPCAUTH_cache,
959         RPCAUTH_RootEOF
960 };
961
962 static const struct rpc_filelist files[] = {
963         [RPCAUTH_lockd] = {
964                 .name = "lockd",
965                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
966         },
967         [RPCAUTH_mount] = {
968                 .name = "mount",
969                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
970         },
971         [RPCAUTH_nfs] = {
972                 .name = "nfs",
973                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
974         },
975         [RPCAUTH_portmap] = {
976                 .name = "portmap",
977                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
978         },
979         [RPCAUTH_statd] = {
980                 .name = "statd",
981                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
982         },
983         [RPCAUTH_nfsd4_cb] = {
984                 .name = "nfsd4_cb",
985                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
986         },
987         [RPCAUTH_cache] = {
988                 .name = "cache",
989                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
990         },
991 };
992
993 static int
994 rpc_fill_super(struct super_block *sb, void *data, int silent)
995 {
996         struct inode *inode;
997         struct dentry *root;
998
999         sb->s_blocksize = PAGE_CACHE_SIZE;
1000         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1001         sb->s_magic = RPCAUTH_GSSMAGIC;
1002         sb->s_op = &s_ops;
1003         sb->s_time_gran = 1;
1004
1005         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1006         if (!inode)
1007                 return -ENOMEM;
1008         sb->s_root = root = d_alloc_root(inode);
1009         if (!root) {
1010                 iput(inode);
1011                 return -ENOMEM;
1012         }
1013         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1014                 return -ENOMEM;
1015         return 0;
1016 }
1017
1018 static int
1019 rpc_get_sb(struct file_system_type *fs_type,
1020                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1021 {
1022         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1023 }
1024
1025 static struct file_system_type rpc_pipe_fs_type = {
1026         .owner          = THIS_MODULE,
1027         .name           = "rpc_pipefs",
1028         .get_sb         = rpc_get_sb,
1029         .kill_sb        = kill_litter_super,
1030 };
1031
1032 static void
1033 init_once(void *foo)
1034 {
1035         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1036
1037         inode_init_once(&rpci->vfs_inode);
1038         rpci->private = NULL;
1039         rpci->nreaders = 0;
1040         rpci->nwriters = 0;
1041         INIT_LIST_HEAD(&rpci->in_upcall);
1042         INIT_LIST_HEAD(&rpci->in_downcall);
1043         INIT_LIST_HEAD(&rpci->pipe);
1044         rpci->pipelen = 0;
1045         init_waitqueue_head(&rpci->waitq);
1046         INIT_DELAYED_WORK(&rpci->queue_timeout,
1047                             rpc_timeout_upcall_queue);
1048         rpci->ops = NULL;
1049 }
1050
1051 int register_rpc_pipefs(void)
1052 {
1053         int err;
1054
1055         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1056                                 sizeof(struct rpc_inode),
1057                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1058                                                 SLAB_MEM_SPREAD),
1059                                 init_once);
1060         if (!rpc_inode_cachep)
1061                 return -ENOMEM;
1062         err = register_filesystem(&rpc_pipe_fs_type);
1063         if (err) {
1064                 kmem_cache_destroy(rpc_inode_cachep);
1065                 return err;
1066         }
1067
1068         return 0;
1069 }
1070
1071 void unregister_rpc_pipefs(void)
1072 {
1073         kmem_cache_destroy(rpc_inode_cachep);
1074         unregister_filesystem(&rpc_pipe_fs_type);
1075 }