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