switch open-coded instances of d_make_root() to new helper
[linux-2.6.git] / net / sunrpc / rpc_pipe.c
1 /*
2  * net/sunrpc/rpc_pipe.c
3  *
4  * Userland/kernel interface for rpcauth_gss.
5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
6  * and fs/sysfs/inode.c
7  *
8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
9  *
10  */
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
14 #include <linux/pagemap.h>
15 #include <linux/mount.h>
16 #include <linux/namei.h>
17 #include <linux/fsnotify.h>
18 #include <linux/kernel.h>
19
20 #include <asm/ioctls.h>
21 #include <linux/fs.h>
22 #include <linux/poll.h>
23 #include <linux/wait.h>
24 #include <linux/seq_file.h>
25
26 #include <linux/sunrpc/clnt.h>
27 #include <linux/workqueue.h>
28 #include <linux/sunrpc/rpc_pipe_fs.h>
29 #include <linux/sunrpc/cache.h>
30
31 static struct vfsmount *rpc_mnt __read_mostly;
32 static int rpc_mount_count;
33
34 static struct file_system_type rpc_pipe_fs_type;
35
36
37 static struct kmem_cache *rpc_inode_cachep __read_mostly;
38
39 #define RPC_UPCALL_TIMEOUT (30*HZ)
40
41 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
42                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
43 {
44         struct rpc_pipe_msg *msg;
45
46         if (list_empty(head))
47                 return;
48         do {
49                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
50                 list_del_init(&msg->list);
51                 msg->errno = err;
52                 destroy_msg(msg);
53         } while (!list_empty(head));
54         wake_up(&rpci->waitq);
55 }
56
57 static void
58 rpc_timeout_upcall_queue(struct work_struct *work)
59 {
60         LIST_HEAD(free_list);
61         struct rpc_inode *rpci =
62                 container_of(work, struct rpc_inode, queue_timeout.work);
63         struct inode *inode = &rpci->vfs_inode;
64         void (*destroy_msg)(struct rpc_pipe_msg *);
65
66         spin_lock(&inode->i_lock);
67         if (rpci->ops == NULL) {
68                 spin_unlock(&inode->i_lock);
69                 return;
70         }
71         destroy_msg = rpci->ops->destroy_msg;
72         if (rpci->nreaders == 0) {
73                 list_splice_init(&rpci->pipe, &free_list);
74                 rpci->pipelen = 0;
75         }
76         spin_unlock(&inode->i_lock);
77         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
78 }
79
80 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
81                                 char __user *dst, size_t buflen)
82 {
83         char *data = (char *)msg->data + msg->copied;
84         size_t mlen = min(msg->len - msg->copied, buflen);
85         unsigned long left;
86
87         left = copy_to_user(dst, data, mlen);
88         if (left == mlen) {
89                 msg->errno = -EFAULT;
90                 return -EFAULT;
91         }
92
93         mlen -= left;
94         msg->copied += mlen;
95         msg->errno = 0;
96         return mlen;
97 }
98 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
99
100 /**
101  * rpc_queue_upcall - queue an upcall message to userspace
102  * @inode: inode of upcall pipe on which to queue given message
103  * @msg: message to queue
104  *
105  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
106  * A userspace process may then later read the upcall by performing a
107  * read on an open file for this inode.  It is up to the caller to
108  * initialize the fields of @msg (other than @msg->list) appropriately.
109  */
110 int
111 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
112 {
113         struct rpc_inode *rpci = RPC_I(inode);
114         int res = -EPIPE;
115
116         spin_lock(&inode->i_lock);
117         if (rpci->ops == NULL)
118                 goto out;
119         if (rpci->nreaders) {
120                 list_add_tail(&msg->list, &rpci->pipe);
121                 rpci->pipelen += msg->len;
122                 res = 0;
123         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
124                 if (list_empty(&rpci->pipe))
125                         queue_delayed_work(rpciod_workqueue,
126                                         &rpci->queue_timeout,
127                                         RPC_UPCALL_TIMEOUT);
128                 list_add_tail(&msg->list, &rpci->pipe);
129                 rpci->pipelen += msg->len;
130                 res = 0;
131         }
132 out:
133         spin_unlock(&inode->i_lock);
134         wake_up(&rpci->waitq);
135         return res;
136 }
137 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
138
139 static inline void
140 rpc_inode_setowner(struct inode *inode, void *private)
141 {
142         RPC_I(inode)->private = private;
143 }
144
145 static void
146 rpc_close_pipes(struct inode *inode)
147 {
148         struct rpc_inode *rpci = RPC_I(inode);
149         const struct rpc_pipe_ops *ops;
150         int need_release;
151
152         mutex_lock(&inode->i_mutex);
153         ops = rpci->ops;
154         if (ops != NULL) {
155                 LIST_HEAD(free_list);
156                 spin_lock(&inode->i_lock);
157                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
158                 rpci->nreaders = 0;
159                 list_splice_init(&rpci->in_upcall, &free_list);
160                 list_splice_init(&rpci->pipe, &free_list);
161                 rpci->pipelen = 0;
162                 rpci->ops = NULL;
163                 spin_unlock(&inode->i_lock);
164                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
165                 rpci->nwriters = 0;
166                 if (need_release && ops->release_pipe)
167                         ops->release_pipe(inode);
168                 cancel_delayed_work_sync(&rpci->queue_timeout);
169         }
170         rpc_inode_setowner(inode, NULL);
171         mutex_unlock(&inode->i_mutex);
172 }
173
174 static struct inode *
175 rpc_alloc_inode(struct super_block *sb)
176 {
177         struct rpc_inode *rpci;
178         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
179         if (!rpci)
180                 return NULL;
181         return &rpci->vfs_inode;
182 }
183
184 static void
185 rpc_i_callback(struct rcu_head *head)
186 {
187         struct inode *inode = container_of(head, struct inode, i_rcu);
188         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
189 }
190
191 static void
192 rpc_destroy_inode(struct inode *inode)
193 {
194         call_rcu(&inode->i_rcu, rpc_i_callback);
195 }
196
197 static int
198 rpc_pipe_open(struct inode *inode, struct file *filp)
199 {
200         struct rpc_inode *rpci = RPC_I(inode);
201         int first_open;
202         int res = -ENXIO;
203
204         mutex_lock(&inode->i_mutex);
205         if (rpci->ops == NULL)
206                 goto out;
207         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
208         if (first_open && rpci->ops->open_pipe) {
209                 res = rpci->ops->open_pipe(inode);
210                 if (res)
211                         goto out;
212         }
213         if (filp->f_mode & FMODE_READ)
214                 rpci->nreaders++;
215         if (filp->f_mode & FMODE_WRITE)
216                 rpci->nwriters++;
217         res = 0;
218 out:
219         mutex_unlock(&inode->i_mutex);
220         return res;
221 }
222
223 static int
224 rpc_pipe_release(struct inode *inode, struct file *filp)
225 {
226         struct rpc_inode *rpci = RPC_I(inode);
227         struct rpc_pipe_msg *msg;
228         int last_close;
229
230         mutex_lock(&inode->i_mutex);
231         if (rpci->ops == NULL)
232                 goto out;
233         msg = filp->private_data;
234         if (msg != NULL) {
235                 spin_lock(&inode->i_lock);
236                 msg->errno = -EAGAIN;
237                 list_del_init(&msg->list);
238                 spin_unlock(&inode->i_lock);
239                 rpci->ops->destroy_msg(msg);
240         }
241         if (filp->f_mode & FMODE_WRITE)
242                 rpci->nwriters --;
243         if (filp->f_mode & FMODE_READ) {
244                 rpci->nreaders --;
245                 if (rpci->nreaders == 0) {
246                         LIST_HEAD(free_list);
247                         spin_lock(&inode->i_lock);
248                         list_splice_init(&rpci->pipe, &free_list);
249                         rpci->pipelen = 0;
250                         spin_unlock(&inode->i_lock);
251                         rpc_purge_list(rpci, &free_list,
252                                         rpci->ops->destroy_msg, -EAGAIN);
253                 }
254         }
255         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
256         if (last_close && rpci->ops->release_pipe)
257                 rpci->ops->release_pipe(inode);
258 out:
259         mutex_unlock(&inode->i_mutex);
260         return 0;
261 }
262
263 static ssize_t
264 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
265 {
266         struct inode *inode = filp->f_path.dentry->d_inode;
267         struct rpc_inode *rpci = RPC_I(inode);
268         struct rpc_pipe_msg *msg;
269         int res = 0;
270
271         mutex_lock(&inode->i_mutex);
272         if (rpci->ops == NULL) {
273                 res = -EPIPE;
274                 goto out_unlock;
275         }
276         msg = filp->private_data;
277         if (msg == NULL) {
278                 spin_lock(&inode->i_lock);
279                 if (!list_empty(&rpci->pipe)) {
280                         msg = list_entry(rpci->pipe.next,
281                                         struct rpc_pipe_msg,
282                                         list);
283                         list_move(&msg->list, &rpci->in_upcall);
284                         rpci->pipelen -= msg->len;
285                         filp->private_data = msg;
286                         msg->copied = 0;
287                 }
288                 spin_unlock(&inode->i_lock);
289                 if (msg == NULL)
290                         goto out_unlock;
291         }
292         /* NOTE: it is up to the callback to update msg->copied */
293         res = rpci->ops->upcall(filp, msg, buf, len);
294         if (res < 0 || msg->len == msg->copied) {
295                 filp->private_data = NULL;
296                 spin_lock(&inode->i_lock);
297                 list_del_init(&msg->list);
298                 spin_unlock(&inode->i_lock);
299                 rpci->ops->destroy_msg(msg);
300         }
301 out_unlock:
302         mutex_unlock(&inode->i_mutex);
303         return res;
304 }
305
306 static ssize_t
307 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
308 {
309         struct inode *inode = filp->f_path.dentry->d_inode;
310         struct rpc_inode *rpci = RPC_I(inode);
311         int res;
312
313         mutex_lock(&inode->i_mutex);
314         res = -EPIPE;
315         if (rpci->ops != NULL)
316                 res = rpci->ops->downcall(filp, buf, len);
317         mutex_unlock(&inode->i_mutex);
318         return res;
319 }
320
321 static unsigned int
322 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
323 {
324         struct rpc_inode *rpci;
325         unsigned int mask = 0;
326
327         rpci = RPC_I(filp->f_path.dentry->d_inode);
328         poll_wait(filp, &rpci->waitq, wait);
329
330         mask = POLLOUT | POLLWRNORM;
331         if (rpci->ops == NULL)
332                 mask |= POLLERR | POLLHUP;
333         if (filp->private_data || !list_empty(&rpci->pipe))
334                 mask |= POLLIN | POLLRDNORM;
335         return mask;
336 }
337
338 static long
339 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
340 {
341         struct inode *inode = filp->f_path.dentry->d_inode;
342         struct rpc_inode *rpci = RPC_I(inode);
343         int len;
344
345         switch (cmd) {
346         case FIONREAD:
347                 spin_lock(&inode->i_lock);
348                 if (rpci->ops == NULL) {
349                         spin_unlock(&inode->i_lock);
350                         return -EPIPE;
351                 }
352                 len = rpci->pipelen;
353                 if (filp->private_data) {
354                         struct rpc_pipe_msg *msg;
355                         msg = filp->private_data;
356                         len += msg->len - msg->copied;
357                 }
358                 spin_unlock(&inode->i_lock);
359                 return put_user(len, (int __user *)arg);
360         default:
361                 return -EINVAL;
362         }
363 }
364
365 static const struct file_operations rpc_pipe_fops = {
366         .owner          = THIS_MODULE,
367         .llseek         = no_llseek,
368         .read           = rpc_pipe_read,
369         .write          = rpc_pipe_write,
370         .poll           = rpc_pipe_poll,
371         .unlocked_ioctl = rpc_pipe_ioctl,
372         .open           = rpc_pipe_open,
373         .release        = rpc_pipe_release,
374 };
375
376 static int
377 rpc_show_info(struct seq_file *m, void *v)
378 {
379         struct rpc_clnt *clnt = m->private;
380
381         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
382         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
383                         clnt->cl_prog, clnt->cl_vers);
384         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
385         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
386         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
387         return 0;
388 }
389
390 static int
391 rpc_info_open(struct inode *inode, struct file *file)
392 {
393         struct rpc_clnt *clnt = NULL;
394         int ret = single_open(file, rpc_show_info, NULL);
395
396         if (!ret) {
397                 struct seq_file *m = file->private_data;
398
399                 spin_lock(&file->f_path.dentry->d_lock);
400                 if (!d_unhashed(file->f_path.dentry))
401                         clnt = RPC_I(inode)->private;
402                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
403                         spin_unlock(&file->f_path.dentry->d_lock);
404                         m->private = clnt;
405                 } else {
406                         spin_unlock(&file->f_path.dentry->d_lock);
407                         single_release(inode, file);
408                         ret = -EINVAL;
409                 }
410         }
411         return ret;
412 }
413
414 static int
415 rpc_info_release(struct inode *inode, struct file *file)
416 {
417         struct seq_file *m = file->private_data;
418         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
419
420         if (clnt)
421                 rpc_release_client(clnt);
422         return single_release(inode, file);
423 }
424
425 static const struct file_operations rpc_info_operations = {
426         .owner          = THIS_MODULE,
427         .open           = rpc_info_open,
428         .read           = seq_read,
429         .llseek         = seq_lseek,
430         .release        = rpc_info_release,
431 };
432
433
434 /*
435  * Description of fs contents.
436  */
437 struct rpc_filelist {
438         const char *name;
439         const struct file_operations *i_fop;
440         umode_t mode;
441 };
442
443 struct vfsmount *rpc_get_mount(void)
444 {
445         int err;
446
447         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count);
448         if (err != 0)
449                 return ERR_PTR(err);
450         return rpc_mnt;
451 }
452 EXPORT_SYMBOL_GPL(rpc_get_mount);
453
454 void rpc_put_mount(void)
455 {
456         simple_release_fs(&rpc_mnt, &rpc_mount_count);
457 }
458 EXPORT_SYMBOL_GPL(rpc_put_mount);
459
460 static int rpc_delete_dentry(const struct dentry *dentry)
461 {
462         return 1;
463 }
464
465 static const struct dentry_operations rpc_dentry_operations = {
466         .d_delete = rpc_delete_dentry,
467 };
468
469 static struct inode *
470 rpc_get_inode(struct super_block *sb, umode_t mode)
471 {
472         struct inode *inode = new_inode(sb);
473         if (!inode)
474                 return NULL;
475         inode->i_ino = get_next_ino();
476         inode->i_mode = mode;
477         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
478         switch (mode & S_IFMT) {
479         case S_IFDIR:
480                 inode->i_fop = &simple_dir_operations;
481                 inode->i_op = &simple_dir_inode_operations;
482                 inc_nlink(inode);
483         default:
484                 break;
485         }
486         return inode;
487 }
488
489 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
490                                umode_t mode,
491                                const struct file_operations *i_fop,
492                                void *private)
493 {
494         struct inode *inode;
495
496         d_drop(dentry);
497         inode = rpc_get_inode(dir->i_sb, mode);
498         if (!inode)
499                 goto out_err;
500         inode->i_ino = iunique(dir->i_sb, 100);
501         if (i_fop)
502                 inode->i_fop = i_fop;
503         if (private)
504                 rpc_inode_setowner(inode, private);
505         d_add(dentry, inode);
506         return 0;
507 out_err:
508         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
509                         __FILE__, __func__, dentry->d_name.name);
510         dput(dentry);
511         return -ENOMEM;
512 }
513
514 static int __rpc_create(struct inode *dir, struct dentry *dentry,
515                         umode_t mode,
516                         const struct file_operations *i_fop,
517                         void *private)
518 {
519         int err;
520
521         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
522         if (err)
523                 return err;
524         fsnotify_create(dir, dentry);
525         return 0;
526 }
527
528 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
529                        umode_t mode,
530                        const struct file_operations *i_fop,
531                        void *private)
532 {
533         int err;
534
535         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
536         if (err)
537                 return err;
538         inc_nlink(dir);
539         fsnotify_mkdir(dir, dentry);
540         return 0;
541 }
542
543 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
544                         umode_t mode,
545                         const struct file_operations *i_fop,
546                         void *private,
547                         const struct rpc_pipe_ops *ops,
548                         int flags)
549 {
550         struct rpc_inode *rpci;
551         int err;
552
553         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
554         if (err)
555                 return err;
556         rpci = RPC_I(dentry->d_inode);
557         rpci->nkern_readwriters = 1;
558         rpci->private = private;
559         rpci->flags = flags;
560         rpci->ops = ops;
561         fsnotify_create(dir, dentry);
562         return 0;
563 }
564
565 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
566 {
567         int ret;
568
569         dget(dentry);
570         ret = simple_rmdir(dir, dentry);
571         d_delete(dentry);
572         dput(dentry);
573         return ret;
574 }
575
576 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
577 {
578         int ret;
579
580         dget(dentry);
581         ret = simple_unlink(dir, dentry);
582         d_delete(dentry);
583         dput(dentry);
584         return ret;
585 }
586
587 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
588 {
589         struct inode *inode = dentry->d_inode;
590         struct rpc_inode *rpci = RPC_I(inode);
591
592         rpci->nkern_readwriters--;
593         if (rpci->nkern_readwriters != 0)
594                 return 0;
595         rpc_close_pipes(inode);
596         return __rpc_unlink(dir, dentry);
597 }
598
599 static struct dentry *__rpc_lookup_create(struct dentry *parent,
600                                           struct qstr *name)
601 {
602         struct dentry *dentry;
603
604         dentry = d_lookup(parent, name);
605         if (!dentry) {
606                 dentry = d_alloc(parent, name);
607                 if (!dentry) {
608                         dentry = ERR_PTR(-ENOMEM);
609                         goto out_err;
610                 }
611         }
612         if (!dentry->d_inode)
613                 d_set_d_op(dentry, &rpc_dentry_operations);
614 out_err:
615         return dentry;
616 }
617
618 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
619                                           struct qstr *name)
620 {
621         struct dentry *dentry;
622
623         dentry = __rpc_lookup_create(parent, name);
624         if (IS_ERR(dentry))
625                 return dentry;
626         if (dentry->d_inode == NULL)
627                 return dentry;
628         dput(dentry);
629         return ERR_PTR(-EEXIST);
630 }
631
632 /*
633  * FIXME: This probably has races.
634  */
635 static void __rpc_depopulate(struct dentry *parent,
636                              const struct rpc_filelist *files,
637                              int start, int eof)
638 {
639         struct inode *dir = parent->d_inode;
640         struct dentry *dentry;
641         struct qstr name;
642         int i;
643
644         for (i = start; i < eof; i++) {
645                 name.name = files[i].name;
646                 name.len = strlen(files[i].name);
647                 name.hash = full_name_hash(name.name, name.len);
648                 dentry = d_lookup(parent, &name);
649
650                 if (dentry == NULL)
651                         continue;
652                 if (dentry->d_inode == NULL)
653                         goto next;
654                 switch (dentry->d_inode->i_mode & S_IFMT) {
655                         default:
656                                 BUG();
657                         case S_IFREG:
658                                 __rpc_unlink(dir, dentry);
659                                 break;
660                         case S_IFDIR:
661                                 __rpc_rmdir(dir, dentry);
662                 }
663 next:
664                 dput(dentry);
665         }
666 }
667
668 static void rpc_depopulate(struct dentry *parent,
669                            const struct rpc_filelist *files,
670                            int start, int eof)
671 {
672         struct inode *dir = parent->d_inode;
673
674         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
675         __rpc_depopulate(parent, files, start, eof);
676         mutex_unlock(&dir->i_mutex);
677 }
678
679 static int rpc_populate(struct dentry *parent,
680                         const struct rpc_filelist *files,
681                         int start, int eof,
682                         void *private)
683 {
684         struct inode *dir = parent->d_inode;
685         struct dentry *dentry;
686         int i, err;
687
688         mutex_lock(&dir->i_mutex);
689         for (i = start; i < eof; i++) {
690                 struct qstr q;
691
692                 q.name = files[i].name;
693                 q.len = strlen(files[i].name);
694                 q.hash = full_name_hash(q.name, q.len);
695                 dentry = __rpc_lookup_create_exclusive(parent, &q);
696                 err = PTR_ERR(dentry);
697                 if (IS_ERR(dentry))
698                         goto out_bad;
699                 switch (files[i].mode & S_IFMT) {
700                         default:
701                                 BUG();
702                         case S_IFREG:
703                                 err = __rpc_create(dir, dentry,
704                                                 files[i].mode,
705                                                 files[i].i_fop,
706                                                 private);
707                                 break;
708                         case S_IFDIR:
709                                 err = __rpc_mkdir(dir, dentry,
710                                                 files[i].mode,
711                                                 NULL,
712                                                 private);
713                 }
714                 if (err != 0)
715                         goto out_bad;
716         }
717         mutex_unlock(&dir->i_mutex);
718         return 0;
719 out_bad:
720         __rpc_depopulate(parent, files, start, eof);
721         mutex_unlock(&dir->i_mutex);
722         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
723                         __FILE__, __func__, parent->d_name.name);
724         return err;
725 }
726
727 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
728                 struct qstr *name, umode_t mode, void *private,
729                 int (*populate)(struct dentry *, void *), void *args_populate)
730 {
731         struct dentry *dentry;
732         struct inode *dir = parent->d_inode;
733         int error;
734
735         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
736         dentry = __rpc_lookup_create_exclusive(parent, name);
737         if (IS_ERR(dentry))
738                 goto out;
739         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
740         if (error != 0)
741                 goto out_err;
742         if (populate != NULL) {
743                 error = populate(dentry, args_populate);
744                 if (error)
745                         goto err_rmdir;
746         }
747 out:
748         mutex_unlock(&dir->i_mutex);
749         return dentry;
750 err_rmdir:
751         __rpc_rmdir(dir, dentry);
752 out_err:
753         dentry = ERR_PTR(error);
754         goto out;
755 }
756
757 static int rpc_rmdir_depopulate(struct dentry *dentry,
758                 void (*depopulate)(struct dentry *))
759 {
760         struct dentry *parent;
761         struct inode *dir;
762         int error;
763
764         parent = dget_parent(dentry);
765         dir = parent->d_inode;
766         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
767         if (depopulate != NULL)
768                 depopulate(dentry);
769         error = __rpc_rmdir(dir, dentry);
770         mutex_unlock(&dir->i_mutex);
771         dput(parent);
772         return error;
773 }
774
775 /**
776  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
777  * @parent: dentry of directory to create new "pipe" in
778  * @name: name of pipe
779  * @private: private data to associate with the pipe, for the caller's use
780  * @ops: operations defining the behavior of the pipe: upcall, downcall,
781  *      release_pipe, open_pipe, and destroy_msg.
782  * @flags: rpc_inode flags
783  *
784  * Data is made available for userspace to read by calls to
785  * rpc_queue_upcall().  The actual reads will result in calls to
786  * @ops->upcall, which will be called with the file pointer,
787  * message, and userspace buffer to copy to.
788  *
789  * Writes can come at any time, and do not necessarily have to be
790  * responses to upcalls.  They will result in calls to @msg->downcall.
791  *
792  * The @private argument passed here will be available to all these methods
793  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
794  */
795 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
796                           void *private, const struct rpc_pipe_ops *ops,
797                           int flags)
798 {
799         struct dentry *dentry;
800         struct inode *dir = parent->d_inode;
801         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
802         struct qstr q;
803         int err;
804
805         if (ops->upcall == NULL)
806                 umode &= ~S_IRUGO;
807         if (ops->downcall == NULL)
808                 umode &= ~S_IWUGO;
809
810         q.name = name;
811         q.len = strlen(name);
812         q.hash = full_name_hash(q.name, q.len),
813
814         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
815         dentry = __rpc_lookup_create(parent, &q);
816         if (IS_ERR(dentry))
817                 goto out;
818         if (dentry->d_inode) {
819                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
820                 if (rpci->private != private ||
821                                 rpci->ops != ops ||
822                                 rpci->flags != flags) {
823                         dput (dentry);
824                         err = -EBUSY;
825                         goto out_err;
826                 }
827                 rpci->nkern_readwriters++;
828                 goto out;
829         }
830
831         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
832                            private, ops, flags);
833         if (err)
834                 goto out_err;
835 out:
836         mutex_unlock(&dir->i_mutex);
837         return dentry;
838 out_err:
839         dentry = ERR_PTR(err);
840         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
841                         __FILE__, __func__, parent->d_name.name, name,
842                         err);
843         goto out;
844 }
845 EXPORT_SYMBOL_GPL(rpc_mkpipe);
846
847 /**
848  * rpc_unlink - remove a pipe
849  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
850  *
851  * After this call, lookups will no longer find the pipe, and any
852  * attempts to read or write using preexisting opens of the pipe will
853  * return -EPIPE.
854  */
855 int
856 rpc_unlink(struct dentry *dentry)
857 {
858         struct dentry *parent;
859         struct inode *dir;
860         int error = 0;
861
862         parent = dget_parent(dentry);
863         dir = parent->d_inode;
864         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
865         error = __rpc_rmpipe(dir, dentry);
866         mutex_unlock(&dir->i_mutex);
867         dput(parent);
868         return error;
869 }
870 EXPORT_SYMBOL_GPL(rpc_unlink);
871
872 enum {
873         RPCAUTH_info,
874         RPCAUTH_EOF
875 };
876
877 static const struct rpc_filelist authfiles[] = {
878         [RPCAUTH_info] = {
879                 .name = "info",
880                 .i_fop = &rpc_info_operations,
881                 .mode = S_IFREG | S_IRUSR,
882         },
883 };
884
885 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
886 {
887         return rpc_populate(dentry,
888                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
889                             private);
890 }
891
892 static void rpc_clntdir_depopulate(struct dentry *dentry)
893 {
894         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
895 }
896
897 /**
898  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
899  * @dentry: dentry from the rpc_pipefs root to the new directory
900  * @name: &struct qstr for the name
901  * @rpc_client: rpc client to associate with this directory
902  *
903  * This creates a directory at the given @path associated with
904  * @rpc_clnt, which will contain a file named "info" with some basic
905  * information about the client, together with any "pipes" that may
906  * later be created using rpc_mkpipe().
907  */
908 struct dentry *rpc_create_client_dir(struct dentry *dentry,
909                                    struct qstr *name,
910                                    struct rpc_clnt *rpc_client)
911 {
912         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
913                         rpc_clntdir_populate, rpc_client);
914 }
915
916 /**
917  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
918  * @dentry: directory to remove
919  */
920 int rpc_remove_client_dir(struct dentry *dentry)
921 {
922         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
923 }
924
925 static const struct rpc_filelist cache_pipefs_files[3] = {
926         [0] = {
927                 .name = "channel",
928                 .i_fop = &cache_file_operations_pipefs,
929                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
930         },
931         [1] = {
932                 .name = "content",
933                 .i_fop = &content_file_operations_pipefs,
934                 .mode = S_IFREG|S_IRUSR,
935         },
936         [2] = {
937                 .name = "flush",
938                 .i_fop = &cache_flush_operations_pipefs,
939                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
940         },
941 };
942
943 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
944 {
945         return rpc_populate(dentry,
946                             cache_pipefs_files, 0, 3,
947                             private);
948 }
949
950 static void rpc_cachedir_depopulate(struct dentry *dentry)
951 {
952         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
953 }
954
955 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
956                                     umode_t umode, struct cache_detail *cd)
957 {
958         return rpc_mkdir_populate(parent, name, umode, NULL,
959                         rpc_cachedir_populate, cd);
960 }
961
962 void rpc_remove_cache_dir(struct dentry *dentry)
963 {
964         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
965 }
966
967 /*
968  * populate the filesystem
969  */
970 static const struct super_operations s_ops = {
971         .alloc_inode    = rpc_alloc_inode,
972         .destroy_inode  = rpc_destroy_inode,
973         .statfs         = simple_statfs,
974 };
975
976 #define RPCAUTH_GSSMAGIC 0x67596969
977
978 /*
979  * We have a single directory with 1 node in it.
980  */
981 enum {
982         RPCAUTH_lockd,
983         RPCAUTH_mount,
984         RPCAUTH_nfs,
985         RPCAUTH_portmap,
986         RPCAUTH_statd,
987         RPCAUTH_nfsd4_cb,
988         RPCAUTH_cache,
989         RPCAUTH_RootEOF
990 };
991
992 static const struct rpc_filelist files[] = {
993         [RPCAUTH_lockd] = {
994                 .name = "lockd",
995                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
996         },
997         [RPCAUTH_mount] = {
998                 .name = "mount",
999                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1000         },
1001         [RPCAUTH_nfs] = {
1002                 .name = "nfs",
1003                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1004         },
1005         [RPCAUTH_portmap] = {
1006                 .name = "portmap",
1007                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1008         },
1009         [RPCAUTH_statd] = {
1010                 .name = "statd",
1011                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1012         },
1013         [RPCAUTH_nfsd4_cb] = {
1014                 .name = "nfsd4_cb",
1015                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1016         },
1017         [RPCAUTH_cache] = {
1018                 .name = "cache",
1019                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1020         },
1021 };
1022
1023 static int
1024 rpc_fill_super(struct super_block *sb, void *data, int silent)
1025 {
1026         struct inode *inode;
1027         struct dentry *root;
1028
1029         sb->s_blocksize = PAGE_CACHE_SIZE;
1030         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1031         sb->s_magic = RPCAUTH_GSSMAGIC;
1032         sb->s_op = &s_ops;
1033         sb->s_time_gran = 1;
1034
1035         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1036         sb->s_root = root = d_make_root(inode);
1037         if (!root)
1038                 return -ENOMEM;
1039         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1040                 return -ENOMEM;
1041         return 0;
1042 }
1043
1044 static struct dentry *
1045 rpc_mount(struct file_system_type *fs_type,
1046                 int flags, const char *dev_name, void *data)
1047 {
1048         return mount_single(fs_type, flags, data, rpc_fill_super);
1049 }
1050
1051 static struct file_system_type rpc_pipe_fs_type = {
1052         .owner          = THIS_MODULE,
1053         .name           = "rpc_pipefs",
1054         .mount          = rpc_mount,
1055         .kill_sb        = kill_litter_super,
1056 };
1057
1058 static void
1059 init_once(void *foo)
1060 {
1061         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1062
1063         inode_init_once(&rpci->vfs_inode);
1064         rpci->private = NULL;
1065         rpci->nreaders = 0;
1066         rpci->nwriters = 0;
1067         INIT_LIST_HEAD(&rpci->in_upcall);
1068         INIT_LIST_HEAD(&rpci->in_downcall);
1069         INIT_LIST_HEAD(&rpci->pipe);
1070         rpci->pipelen = 0;
1071         init_waitqueue_head(&rpci->waitq);
1072         INIT_DELAYED_WORK(&rpci->queue_timeout,
1073                             rpc_timeout_upcall_queue);
1074         rpci->ops = NULL;
1075 }
1076
1077 int register_rpc_pipefs(void)
1078 {
1079         int err;
1080
1081         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1082                                 sizeof(struct rpc_inode),
1083                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1084                                                 SLAB_MEM_SPREAD),
1085                                 init_once);
1086         if (!rpc_inode_cachep)
1087                 return -ENOMEM;
1088         err = register_filesystem(&rpc_pipe_fs_type);
1089         if (err) {
1090                 kmem_cache_destroy(rpc_inode_cachep);
1091                 return err;
1092         }
1093
1094         return 0;
1095 }
1096
1097 void unregister_rpc_pipefs(void)
1098 {
1099         kmem_cache_destroy(rpc_inode_cachep);
1100         unregister_filesystem(&rpc_pipe_fs_type);
1101 }
1102
1103 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1104 MODULE_ALIAS("rpc_pipefs");