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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_init(&msg->list);
51                 msg->errno = err;
52                 destroy_msg(msg);
53         } while (!list_empty(head));
54         wake_up(&rpci->waitq);
55 }
56
57 static void
58 rpc_timeout_upcall_queue(struct work_struct *work)
59 {
60         LIST_HEAD(free_list);
61         struct rpc_inode *rpci =
62                 container_of(work, struct rpc_inode, queue_timeout.work);
63         struct inode *inode = &rpci->vfs_inode;
64         void (*destroy_msg)(struct rpc_pipe_msg *);
65
66         spin_lock(&inode->i_lock);
67         if (rpci->ops == NULL) {
68                 spin_unlock(&inode->i_lock);
69                 return;
70         }
71         destroy_msg = rpci->ops->destroy_msg;
72         if (rpci->nreaders == 0) {
73                 list_splice_init(&rpci->pipe, &free_list);
74                 rpci->pipelen = 0;
75         }
76         spin_unlock(&inode->i_lock);
77         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
78 }
79
80 /**
81  * rpc_queue_upcall - queue an upcall message to userspace
82  * @inode: inode of upcall pipe on which to queue given message
83  * @msg: message to queue
84  *
85  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
86  * A userspace process may then later read the upcall by performing a
87  * read on an open file for this inode.  It is up to the caller to
88  * initialize the fields of @msg (other than @msg->list) appropriately.
89  */
90 int
91 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
92 {
93         struct rpc_inode *rpci = RPC_I(inode);
94         int res = -EPIPE;
95
96         spin_lock(&inode->i_lock);
97         if (rpci->ops == NULL)
98                 goto out;
99         if (rpci->nreaders) {
100                 list_add_tail(&msg->list, &rpci->pipe);
101                 rpci->pipelen += msg->len;
102                 res = 0;
103         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
104                 if (list_empty(&rpci->pipe))
105                         queue_delayed_work(rpciod_workqueue,
106                                         &rpci->queue_timeout,
107                                         RPC_UPCALL_TIMEOUT);
108                 list_add_tail(&msg->list, &rpci->pipe);
109                 rpci->pipelen += msg->len;
110                 res = 0;
111         }
112 out:
113         spin_unlock(&inode->i_lock);
114         wake_up(&rpci->waitq);
115         return res;
116 }
117 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
118
119 static inline void
120 rpc_inode_setowner(struct inode *inode, void *private)
121 {
122         RPC_I(inode)->private = private;
123 }
124
125 static void
126 rpc_close_pipes(struct inode *inode)
127 {
128         struct rpc_inode *rpci = RPC_I(inode);
129         const struct rpc_pipe_ops *ops;
130         int need_release;
131
132         mutex_lock(&inode->i_mutex);
133         ops = rpci->ops;
134         if (ops != NULL) {
135                 LIST_HEAD(free_list);
136                 spin_lock(&inode->i_lock);
137                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
138                 rpci->nreaders = 0;
139                 list_splice_init(&rpci->in_upcall, &free_list);
140                 list_splice_init(&rpci->pipe, &free_list);
141                 rpci->pipelen = 0;
142                 rpci->ops = NULL;
143                 spin_unlock(&inode->i_lock);
144                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
145                 rpci->nwriters = 0;
146                 if (need_release && ops->release_pipe)
147                         ops->release_pipe(inode);
148                 cancel_delayed_work_sync(&rpci->queue_timeout);
149         }
150         rpc_inode_setowner(inode, NULL);
151         mutex_unlock(&inode->i_mutex);
152 }
153
154 static struct inode *
155 rpc_alloc_inode(struct super_block *sb)
156 {
157         struct rpc_inode *rpci;
158         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
159         if (!rpci)
160                 return NULL;
161         return &rpci->vfs_inode;
162 }
163
164 static void
165 rpc_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 = filp->private_data;
207         if (msg != NULL) {
208                 spin_lock(&inode->i_lock);
209                 msg->errno = -EAGAIN;
210                 list_del_init(&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_init(&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 = 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 = NULL;
367         int ret = single_open(file, rpc_show_info, NULL);
368
369         if (!ret) {
370                 struct seq_file *m = file->private_data;
371
372                 spin_lock(&file->f_path.dentry->d_lock);
373                 if (!d_unhashed(file->f_path.dentry))
374                         clnt = RPC_I(inode)->private;
375                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
376                         spin_unlock(&file->f_path.dentry->d_lock);
377                         m->private = clnt;
378                 } else {
379                         spin_unlock(&file->f_path.dentry->d_lock);
380                         single_release(inode, file);
381                         ret = -EINVAL;
382                 }
383         }
384         return ret;
385 }
386
387 static int
388 rpc_info_release(struct inode *inode, struct file *file)
389 {
390         struct seq_file *m = file->private_data;
391         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
392
393         if (clnt)
394                 rpc_release_client(clnt);
395         return single_release(inode, file);
396 }
397
398 static const struct file_operations rpc_info_operations = {
399         .owner          = THIS_MODULE,
400         .open           = rpc_info_open,
401         .read           = seq_read,
402         .llseek         = seq_lseek,
403         .release        = rpc_info_release,
404 };
405
406
407 /*
408  * Description of fs contents.
409  */
410 struct rpc_filelist {
411         const char *name;
412         const struct file_operations *i_fop;
413         umode_t mode;
414 };
415
416 struct vfsmount *rpc_get_mount(void)
417 {
418         int err;
419
420         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
421         if (err != 0)
422                 return ERR_PTR(err);
423         return rpc_mount;
424 }
425 EXPORT_SYMBOL_GPL(rpc_get_mount);
426
427 void rpc_put_mount(void)
428 {
429         simple_release_fs(&rpc_mount, &rpc_mount_count);
430 }
431 EXPORT_SYMBOL_GPL(rpc_put_mount);
432
433 static int rpc_delete_dentry(struct dentry *dentry)
434 {
435         return 1;
436 }
437
438 static const struct dentry_operations rpc_dentry_operations = {
439         .d_delete = rpc_delete_dentry,
440 };
441
442 static struct inode *
443 rpc_get_inode(struct super_block *sb, umode_t mode)
444 {
445         struct inode *inode = new_inode(sb);
446         if (!inode)
447                 return NULL;
448         inode->i_ino = get_next_ino();
449         inode->i_mode = mode;
450         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
451         switch(mode & S_IFMT) {
452                 case S_IFDIR:
453                         inode->i_fop = &simple_dir_operations;
454                         inode->i_op = &simple_dir_inode_operations;
455                         inc_nlink(inode);
456                 default:
457                         break;
458         }
459         return inode;
460 }
461
462 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
463                                umode_t mode,
464                                const struct file_operations *i_fop,
465                                void *private)
466 {
467         struct inode *inode;
468
469         BUG_ON(!d_unhashed(dentry));
470         inode = rpc_get_inode(dir->i_sb, mode);
471         if (!inode)
472                 goto out_err;
473         inode->i_ino = iunique(dir->i_sb, 100);
474         if (i_fop)
475                 inode->i_fop = i_fop;
476         if (private)
477                 rpc_inode_setowner(inode, private);
478         d_add(dentry, inode);
479         return 0;
480 out_err:
481         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
482                         __FILE__, __func__, dentry->d_name.name);
483         dput(dentry);
484         return -ENOMEM;
485 }
486
487 static int __rpc_create(struct inode *dir, struct dentry *dentry,
488                         umode_t mode,
489                         const struct file_operations *i_fop,
490                         void *private)
491 {
492         int err;
493
494         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
495         if (err)
496                 return err;
497         fsnotify_create(dir, dentry);
498         return 0;
499 }
500
501 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
502                        umode_t mode,
503                        const struct file_operations *i_fop,
504                        void *private)
505 {
506         int err;
507
508         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
509         if (err)
510                 return err;
511         inc_nlink(dir);
512         fsnotify_mkdir(dir, dentry);
513         return 0;
514 }
515
516 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
517                         umode_t mode,
518                         const struct file_operations *i_fop,
519                         void *private,
520                         const struct rpc_pipe_ops *ops,
521                         int flags)
522 {
523         struct rpc_inode *rpci;
524         int err;
525
526         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
527         if (err)
528                 return err;
529         rpci = RPC_I(dentry->d_inode);
530         rpci->nkern_readwriters = 1;
531         rpci->private = private;
532         rpci->flags = flags;
533         rpci->ops = ops;
534         fsnotify_create(dir, dentry);
535         return 0;
536 }
537
538 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
539 {
540         int ret;
541
542         dget(dentry);
543         ret = simple_rmdir(dir, dentry);
544         d_delete(dentry);
545         dput(dentry);
546         return ret;
547 }
548
549 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
550 {
551         int ret;
552
553         dget(dentry);
554         ret = simple_unlink(dir, dentry);
555         d_delete(dentry);
556         dput(dentry);
557         return ret;
558 }
559
560 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
561 {
562         struct inode *inode = dentry->d_inode;
563         struct rpc_inode *rpci = RPC_I(inode);
564
565         rpci->nkern_readwriters--;
566         if (rpci->nkern_readwriters != 0)
567                 return 0;
568         rpc_close_pipes(inode);
569         return __rpc_unlink(dir, dentry);
570 }
571
572 static struct dentry *__rpc_lookup_create(struct dentry *parent,
573                                           struct qstr *name)
574 {
575         struct dentry *dentry;
576
577         dentry = d_lookup(parent, name);
578         if (!dentry) {
579                 dentry = d_alloc(parent, name);
580                 if (!dentry) {
581                         dentry = ERR_PTR(-ENOMEM);
582                         goto out_err;
583                 }
584         }
585         if (!dentry->d_inode)
586                 dentry->d_op = &rpc_dentry_operations;
587 out_err:
588         return dentry;
589 }
590
591 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
592                                           struct qstr *name)
593 {
594         struct dentry *dentry;
595
596         dentry = __rpc_lookup_create(parent, name);
597         if (IS_ERR(dentry))
598                 return dentry;
599         if (dentry->d_inode == NULL)
600                 return dentry;
601         dput(dentry);
602         return ERR_PTR(-EEXIST);
603 }
604
605 /*
606  * FIXME: This probably has races.
607  */
608 static void __rpc_depopulate(struct dentry *parent,
609                              const struct rpc_filelist *files,
610                              int start, int eof)
611 {
612         struct inode *dir = parent->d_inode;
613         struct dentry *dentry;
614         struct qstr name;
615         int i;
616
617         for (i = start; i < eof; i++) {
618                 name.name = files[i].name;
619                 name.len = strlen(files[i].name);
620                 name.hash = full_name_hash(name.name, name.len);
621                 dentry = d_lookup(parent, &name);
622
623                 if (dentry == NULL)
624                         continue;
625                 if (dentry->d_inode == NULL)
626                         goto next;
627                 switch (dentry->d_inode->i_mode & S_IFMT) {
628                         default:
629                                 BUG();
630                         case S_IFREG:
631                                 __rpc_unlink(dir, dentry);
632                                 break;
633                         case S_IFDIR:
634                                 __rpc_rmdir(dir, dentry);
635                 }
636 next:
637                 dput(dentry);
638         }
639 }
640
641 static void rpc_depopulate(struct dentry *parent,
642                            const struct rpc_filelist *files,
643                            int start, int eof)
644 {
645         struct inode *dir = parent->d_inode;
646
647         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
648         __rpc_depopulate(parent, files, start, eof);
649         mutex_unlock(&dir->i_mutex);
650 }
651
652 static int rpc_populate(struct dentry *parent,
653                         const struct rpc_filelist *files,
654                         int start, int eof,
655                         void *private)
656 {
657         struct inode *dir = parent->d_inode;
658         struct dentry *dentry;
659         int i, err;
660
661         mutex_lock(&dir->i_mutex);
662         for (i = start; i < eof; i++) {
663                 struct qstr q;
664
665                 q.name = files[i].name;
666                 q.len = strlen(files[i].name);
667                 q.hash = full_name_hash(q.name, q.len);
668                 dentry = __rpc_lookup_create_exclusive(parent, &q);
669                 err = PTR_ERR(dentry);
670                 if (IS_ERR(dentry))
671                         goto out_bad;
672                 switch (files[i].mode & S_IFMT) {
673                         default:
674                                 BUG();
675                         case S_IFREG:
676                                 err = __rpc_create(dir, dentry,
677                                                 files[i].mode,
678                                                 files[i].i_fop,
679                                                 private);
680                                 break;
681                         case S_IFDIR:
682                                 err = __rpc_mkdir(dir, dentry,
683                                                 files[i].mode,
684                                                 NULL,
685                                                 private);
686                 }
687                 if (err != 0)
688                         goto out_bad;
689         }
690         mutex_unlock(&dir->i_mutex);
691         return 0;
692 out_bad:
693         __rpc_depopulate(parent, files, start, eof);
694         mutex_unlock(&dir->i_mutex);
695         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
696                         __FILE__, __func__, parent->d_name.name);
697         return err;
698 }
699
700 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
701                 struct qstr *name, umode_t mode, void *private,
702                 int (*populate)(struct dentry *, void *), void *args_populate)
703 {
704         struct dentry *dentry;
705         struct inode *dir = parent->d_inode;
706         int error;
707
708         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
709         dentry = __rpc_lookup_create_exclusive(parent, name);
710         if (IS_ERR(dentry))
711                 goto out;
712         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
713         if (error != 0)
714                 goto out_err;
715         if (populate != NULL) {
716                 error = populate(dentry, args_populate);
717                 if (error)
718                         goto err_rmdir;
719         }
720 out:
721         mutex_unlock(&dir->i_mutex);
722         return dentry;
723 err_rmdir:
724         __rpc_rmdir(dir, dentry);
725 out_err:
726         dentry = ERR_PTR(error);
727         goto out;
728 }
729
730 static int rpc_rmdir_depopulate(struct dentry *dentry,
731                 void (*depopulate)(struct dentry *))
732 {
733         struct dentry *parent;
734         struct inode *dir;
735         int error;
736
737         parent = dget_parent(dentry);
738         dir = parent->d_inode;
739         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
740         if (depopulate != NULL)
741                 depopulate(dentry);
742         error = __rpc_rmdir(dir, dentry);
743         mutex_unlock(&dir->i_mutex);
744         dput(parent);
745         return error;
746 }
747
748 /**
749  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
750  * @parent: dentry of directory to create new "pipe" in
751  * @name: name of pipe
752  * @private: private data to associate with the pipe, for the caller's use
753  * @ops: operations defining the behavior of the pipe: upcall, downcall,
754  *      release_pipe, open_pipe, and destroy_msg.
755  * @flags: rpc_inode flags
756  *
757  * Data is made available for userspace to read by calls to
758  * rpc_queue_upcall().  The actual reads will result in calls to
759  * @ops->upcall, which will be called with the file pointer,
760  * message, and userspace buffer to copy to.
761  *
762  * Writes can come at any time, and do not necessarily have to be
763  * responses to upcalls.  They will result in calls to @msg->downcall.
764  *
765  * The @private argument passed here will be available to all these methods
766  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
767  */
768 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
769                           void *private, const struct rpc_pipe_ops *ops,
770                           int flags)
771 {
772         struct dentry *dentry;
773         struct inode *dir = parent->d_inode;
774         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
775         struct qstr q;
776         int err;
777
778         if (ops->upcall == NULL)
779                 umode &= ~S_IRUGO;
780         if (ops->downcall == NULL)
781                 umode &= ~S_IWUGO;
782
783         q.name = name;
784         q.len = strlen(name);
785         q.hash = full_name_hash(q.name, q.len),
786
787         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
788         dentry = __rpc_lookup_create(parent, &q);
789         if (IS_ERR(dentry))
790                 goto out;
791         if (dentry->d_inode) {
792                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
793                 if (rpci->private != private ||
794                                 rpci->ops != ops ||
795                                 rpci->flags != flags) {
796                         dput (dentry);
797                         err = -EBUSY;
798                         goto out_err;
799                 }
800                 rpci->nkern_readwriters++;
801                 goto out;
802         }
803
804         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
805                            private, ops, flags);
806         if (err)
807                 goto out_err;
808 out:
809         mutex_unlock(&dir->i_mutex);
810         return dentry;
811 out_err:
812         dentry = ERR_PTR(err);
813         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
814                         __FILE__, __func__, parent->d_name.name, name,
815                         err);
816         goto out;
817 }
818 EXPORT_SYMBOL_GPL(rpc_mkpipe);
819
820 /**
821  * rpc_unlink - remove a pipe
822  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
823  *
824  * After this call, lookups will no longer find the pipe, and any
825  * attempts to read or write using preexisting opens of the pipe will
826  * return -EPIPE.
827  */
828 int
829 rpc_unlink(struct dentry *dentry)
830 {
831         struct dentry *parent;
832         struct inode *dir;
833         int error = 0;
834
835         parent = dget_parent(dentry);
836         dir = parent->d_inode;
837         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
838         error = __rpc_rmpipe(dir, dentry);
839         mutex_unlock(&dir->i_mutex);
840         dput(parent);
841         return error;
842 }
843 EXPORT_SYMBOL_GPL(rpc_unlink);
844
845 enum {
846         RPCAUTH_info,
847         RPCAUTH_EOF
848 };
849
850 static const struct rpc_filelist authfiles[] = {
851         [RPCAUTH_info] = {
852                 .name = "info",
853                 .i_fop = &rpc_info_operations,
854                 .mode = S_IFREG | S_IRUSR,
855         },
856 };
857
858 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
859 {
860         return rpc_populate(dentry,
861                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
862                             private);
863 }
864
865 static void rpc_clntdir_depopulate(struct dentry *dentry)
866 {
867         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
868 }
869
870 /**
871  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
872  * @dentry: dentry from the rpc_pipefs root to the new directory
873  * @name: &struct qstr for the name
874  * @rpc_client: rpc client to associate with this directory
875  *
876  * This creates a directory at the given @path associated with
877  * @rpc_clnt, which will contain a file named "info" with some basic
878  * information about the client, together with any "pipes" that may
879  * later be created using rpc_mkpipe().
880  */
881 struct dentry *rpc_create_client_dir(struct dentry *dentry,
882                                    struct qstr *name,
883                                    struct rpc_clnt *rpc_client)
884 {
885         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
886                         rpc_clntdir_populate, rpc_client);
887 }
888
889 /**
890  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
891  * @dentry: directory to remove
892  */
893 int rpc_remove_client_dir(struct dentry *dentry)
894 {
895         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
896 }
897
898 static const struct rpc_filelist cache_pipefs_files[3] = {
899         [0] = {
900                 .name = "channel",
901                 .i_fop = &cache_file_operations_pipefs,
902                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
903         },
904         [1] = {
905                 .name = "content",
906                 .i_fop = &content_file_operations_pipefs,
907                 .mode = S_IFREG|S_IRUSR,
908         },
909         [2] = {
910                 .name = "flush",
911                 .i_fop = &cache_flush_operations_pipefs,
912                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
913         },
914 };
915
916 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
917 {
918         return rpc_populate(dentry,
919                             cache_pipefs_files, 0, 3,
920                             private);
921 }
922
923 static void rpc_cachedir_depopulate(struct dentry *dentry)
924 {
925         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
926 }
927
928 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
929                                     mode_t umode, struct cache_detail *cd)
930 {
931         return rpc_mkdir_populate(parent, name, umode, NULL,
932                         rpc_cachedir_populate, cd);
933 }
934
935 void rpc_remove_cache_dir(struct dentry *dentry)
936 {
937         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
938 }
939
940 /*
941  * populate the filesystem
942  */
943 static const struct super_operations s_ops = {
944         .alloc_inode    = rpc_alloc_inode,
945         .destroy_inode  = rpc_destroy_inode,
946         .statfs         = simple_statfs,
947 };
948
949 #define RPCAUTH_GSSMAGIC 0x67596969
950
951 /*
952  * We have a single directory with 1 node in it.
953  */
954 enum {
955         RPCAUTH_lockd,
956         RPCAUTH_mount,
957         RPCAUTH_nfs,
958         RPCAUTH_portmap,
959         RPCAUTH_statd,
960         RPCAUTH_nfsd4_cb,
961         RPCAUTH_cache,
962         RPCAUTH_RootEOF
963 };
964
965 static const struct rpc_filelist files[] = {
966         [RPCAUTH_lockd] = {
967                 .name = "lockd",
968                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
969         },
970         [RPCAUTH_mount] = {
971                 .name = "mount",
972                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
973         },
974         [RPCAUTH_nfs] = {
975                 .name = "nfs",
976                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
977         },
978         [RPCAUTH_portmap] = {
979                 .name = "portmap",
980                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
981         },
982         [RPCAUTH_statd] = {
983                 .name = "statd",
984                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
985         },
986         [RPCAUTH_nfsd4_cb] = {
987                 .name = "nfsd4_cb",
988                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
989         },
990         [RPCAUTH_cache] = {
991                 .name = "cache",
992                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
993         },
994 };
995
996 static int
997 rpc_fill_super(struct super_block *sb, void *data, int silent)
998 {
999         struct inode *inode;
1000         struct dentry *root;
1001
1002         sb->s_blocksize = PAGE_CACHE_SIZE;
1003         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1004         sb->s_magic = RPCAUTH_GSSMAGIC;
1005         sb->s_op = &s_ops;
1006         sb->s_time_gran = 1;
1007
1008         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1009         if (!inode)
1010                 return -ENOMEM;
1011         sb->s_root = root = d_alloc_root(inode);
1012         if (!root) {
1013                 iput(inode);
1014                 return -ENOMEM;
1015         }
1016         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1017                 return -ENOMEM;
1018         return 0;
1019 }
1020
1021 static int
1022 rpc_get_sb(struct file_system_type *fs_type,
1023                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1024 {
1025         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1026 }
1027
1028 static struct file_system_type rpc_pipe_fs_type = {
1029         .owner          = THIS_MODULE,
1030         .name           = "rpc_pipefs",
1031         .get_sb         = rpc_get_sb,
1032         .kill_sb        = kill_litter_super,
1033 };
1034
1035 static void
1036 init_once(void *foo)
1037 {
1038         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1039
1040         inode_init_once(&rpci->vfs_inode);
1041         rpci->private = NULL;
1042         rpci->nreaders = 0;
1043         rpci->nwriters = 0;
1044         INIT_LIST_HEAD(&rpci->in_upcall);
1045         INIT_LIST_HEAD(&rpci->in_downcall);
1046         INIT_LIST_HEAD(&rpci->pipe);
1047         rpci->pipelen = 0;
1048         init_waitqueue_head(&rpci->waitq);
1049         INIT_DELAYED_WORK(&rpci->queue_timeout,
1050                             rpc_timeout_upcall_queue);
1051         rpci->ops = NULL;
1052 }
1053
1054 int register_rpc_pipefs(void)
1055 {
1056         int err;
1057
1058         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1059                                 sizeof(struct rpc_inode),
1060                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1061                                                 SLAB_MEM_SPREAD),
1062                                 init_once);
1063         if (!rpc_inode_cachep)
1064                 return -ENOMEM;
1065         err = register_filesystem(&rpc_pipe_fs_type);
1066         if (err) {
1067                 kmem_cache_destroy(rpc_inode_cachep);
1068                 return err;
1069         }
1070
1071         return 0;
1072 }
1073
1074 void unregister_rpc_pipefs(void)
1075 {
1076         kmem_cache_destroy(rpc_inode_cachep);
1077         unregister_filesystem(&rpc_pipe_fs_type);
1078 }