Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / 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/dnotify.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 int
80 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
81 {
82         struct rpc_inode *rpci = RPC_I(inode);
83         int res = -EPIPE;
84
85         spin_lock(&inode->i_lock);
86         if (rpci->ops == NULL)
87                 goto out;
88         if (rpci->nreaders) {
89                 list_add_tail(&msg->list, &rpci->pipe);
90                 rpci->pipelen += msg->len;
91                 res = 0;
92         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
93                 if (list_empty(&rpci->pipe))
94                         queue_delayed_work(rpciod_workqueue,
95                                         &rpci->queue_timeout,
96                                         RPC_UPCALL_TIMEOUT);
97                 list_add_tail(&msg->list, &rpci->pipe);
98                 rpci->pipelen += msg->len;
99                 res = 0;
100         }
101 out:
102         spin_unlock(&inode->i_lock);
103         wake_up(&rpci->waitq);
104         return res;
105 }
106
107 static inline void
108 rpc_inode_setowner(struct inode *inode, void *private)
109 {
110         RPC_I(inode)->private = private;
111 }
112
113 static void
114 rpc_close_pipes(struct inode *inode)
115 {
116         struct rpc_inode *rpci = RPC_I(inode);
117         struct rpc_pipe_ops *ops;
118
119         mutex_lock(&inode->i_mutex);
120         ops = rpci->ops;
121         if (ops != NULL) {
122                 LIST_HEAD(free_list);
123
124                 spin_lock(&inode->i_lock);
125                 rpci->nreaders = 0;
126                 list_splice_init(&rpci->in_upcall, &free_list);
127                 list_splice_init(&rpci->pipe, &free_list);
128                 rpci->pipelen = 0;
129                 rpci->ops = NULL;
130                 spin_unlock(&inode->i_lock);
131                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
132                 rpci->nwriters = 0;
133                 if (ops->release_pipe)
134                         ops->release_pipe(inode);
135                 cancel_delayed_work_sync(&rpci->queue_timeout);
136         }
137         rpc_inode_setowner(inode, NULL);
138         mutex_unlock(&inode->i_mutex);
139 }
140
141 static struct inode *
142 rpc_alloc_inode(struct super_block *sb)
143 {
144         struct rpc_inode *rpci;
145         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
146         if (!rpci)
147                 return NULL;
148         return &rpci->vfs_inode;
149 }
150
151 static void
152 rpc_destroy_inode(struct inode *inode)
153 {
154         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
155 }
156
157 static int
158 rpc_pipe_open(struct inode *inode, struct file *filp)
159 {
160         struct rpc_inode *rpci = RPC_I(inode);
161         int res = -ENXIO;
162
163         mutex_lock(&inode->i_mutex);
164         if (rpci->ops != NULL) {
165                 if (filp->f_mode & FMODE_READ)
166                         rpci->nreaders ++;
167                 if (filp->f_mode & FMODE_WRITE)
168                         rpci->nwriters ++;
169                 res = 0;
170         }
171         mutex_unlock(&inode->i_mutex);
172         return res;
173 }
174
175 static int
176 rpc_pipe_release(struct inode *inode, struct file *filp)
177 {
178         struct rpc_inode *rpci = RPC_I(inode);
179         struct rpc_pipe_msg *msg;
180
181         mutex_lock(&inode->i_mutex);
182         if (rpci->ops == NULL)
183                 goto out;
184         msg = (struct rpc_pipe_msg *)filp->private_data;
185         if (msg != NULL) {
186                 spin_lock(&inode->i_lock);
187                 msg->errno = -EAGAIN;
188                 list_del(&msg->list);
189                 spin_unlock(&inode->i_lock);
190                 rpci->ops->destroy_msg(msg);
191         }
192         if (filp->f_mode & FMODE_WRITE)
193                 rpci->nwriters --;
194         if (filp->f_mode & FMODE_READ) {
195                 rpci->nreaders --;
196                 if (rpci->nreaders == 0) {
197                         LIST_HEAD(free_list);
198                         spin_lock(&inode->i_lock);
199                         list_splice_init(&rpci->pipe, &free_list);
200                         rpci->pipelen = 0;
201                         spin_unlock(&inode->i_lock);
202                         rpc_purge_list(rpci, &free_list,
203                                         rpci->ops->destroy_msg, -EAGAIN);
204                 }
205         }
206         if (rpci->ops->release_pipe)
207                 rpci->ops->release_pipe(inode);
208 out:
209         mutex_unlock(&inode->i_mutex);
210         return 0;
211 }
212
213 static ssize_t
214 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
215 {
216         struct inode *inode = filp->f_path.dentry->d_inode;
217         struct rpc_inode *rpci = RPC_I(inode);
218         struct rpc_pipe_msg *msg;
219         int res = 0;
220
221         mutex_lock(&inode->i_mutex);
222         if (rpci->ops == NULL) {
223                 res = -EPIPE;
224                 goto out_unlock;
225         }
226         msg = filp->private_data;
227         if (msg == NULL) {
228                 spin_lock(&inode->i_lock);
229                 if (!list_empty(&rpci->pipe)) {
230                         msg = list_entry(rpci->pipe.next,
231                                         struct rpc_pipe_msg,
232                                         list);
233                         list_move(&msg->list, &rpci->in_upcall);
234                         rpci->pipelen -= msg->len;
235                         filp->private_data = msg;
236                         msg->copied = 0;
237                 }
238                 spin_unlock(&inode->i_lock);
239                 if (msg == NULL)
240                         goto out_unlock;
241         }
242         /* NOTE: it is up to the callback to update msg->copied */
243         res = rpci->ops->upcall(filp, msg, buf, len);
244         if (res < 0 || msg->len == msg->copied) {
245                 filp->private_data = NULL;
246                 spin_lock(&inode->i_lock);
247                 list_del(&msg->list);
248                 spin_unlock(&inode->i_lock);
249                 rpci->ops->destroy_msg(msg);
250         }
251 out_unlock:
252         mutex_unlock(&inode->i_mutex);
253         return res;
254 }
255
256 static ssize_t
257 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
258 {
259         struct inode *inode = filp->f_path.dentry->d_inode;
260         struct rpc_inode *rpci = RPC_I(inode);
261         int res;
262
263         mutex_lock(&inode->i_mutex);
264         res = -EPIPE;
265         if (rpci->ops != NULL)
266                 res = rpci->ops->downcall(filp, buf, len);
267         mutex_unlock(&inode->i_mutex);
268         return res;
269 }
270
271 static unsigned int
272 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
273 {
274         struct rpc_inode *rpci;
275         unsigned int mask = 0;
276
277         rpci = RPC_I(filp->f_path.dentry->d_inode);
278         poll_wait(filp, &rpci->waitq, wait);
279
280         mask = POLLOUT | POLLWRNORM;
281         if (rpci->ops == NULL)
282                 mask |= POLLERR | POLLHUP;
283         if (!list_empty(&rpci->pipe))
284                 mask |= POLLIN | POLLRDNORM;
285         return mask;
286 }
287
288 static int
289 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
290                 unsigned int cmd, unsigned long arg)
291 {
292         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
293         int len;
294
295         switch (cmd) {
296         case FIONREAD:
297                 if (rpci->ops == NULL)
298                         return -EPIPE;
299                 len = rpci->pipelen;
300                 if (filp->private_data) {
301                         struct rpc_pipe_msg *msg;
302                         msg = (struct rpc_pipe_msg *)filp->private_data;
303                         len += msg->len - msg->copied;
304                 }
305                 return put_user(len, (int __user *)arg);
306         default:
307                 return -EINVAL;
308         }
309 }
310
311 static const struct file_operations rpc_pipe_fops = {
312         .owner          = THIS_MODULE,
313         .llseek         = no_llseek,
314         .read           = rpc_pipe_read,
315         .write          = rpc_pipe_write,
316         .poll           = rpc_pipe_poll,
317         .ioctl          = rpc_pipe_ioctl,
318         .open           = rpc_pipe_open,
319         .release        = rpc_pipe_release,
320 };
321
322 static int
323 rpc_show_info(struct seq_file *m, void *v)
324 {
325         struct rpc_clnt *clnt = m->private;
326
327         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
328         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
329                         clnt->cl_prog, clnt->cl_vers);
330         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
331         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
332         return 0;
333 }
334
335 static int
336 rpc_info_open(struct inode *inode, struct file *file)
337 {
338         struct rpc_clnt *clnt;
339         int ret = single_open(file, rpc_show_info, NULL);
340
341         if (!ret) {
342                 struct seq_file *m = file->private_data;
343                 mutex_lock(&inode->i_mutex);
344                 clnt = RPC_I(inode)->private;
345                 if (clnt) {
346                         kref_get(&clnt->cl_kref);
347                         m->private = clnt;
348                 } else {
349                         single_release(inode, file);
350                         ret = -EINVAL;
351                 }
352                 mutex_unlock(&inode->i_mutex);
353         }
354         return ret;
355 }
356
357 static int
358 rpc_info_release(struct inode *inode, struct file *file)
359 {
360         struct seq_file *m = file->private_data;
361         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
362
363         if (clnt)
364                 rpc_release_client(clnt);
365         return single_release(inode, file);
366 }
367
368 static const struct file_operations rpc_info_operations = {
369         .owner          = THIS_MODULE,
370         .open           = rpc_info_open,
371         .read           = seq_read,
372         .llseek         = seq_lseek,
373         .release        = rpc_info_release,
374 };
375
376
377 /*
378  * We have a single directory with 1 node in it.
379  */
380 enum {
381         RPCAUTH_Root = 1,
382         RPCAUTH_lockd,
383         RPCAUTH_mount,
384         RPCAUTH_nfs,
385         RPCAUTH_portmap,
386         RPCAUTH_statd,
387         RPCAUTH_RootEOF
388 };
389
390 /*
391  * Description of fs contents.
392  */
393 struct rpc_filelist {
394         char *name;
395         const struct file_operations *i_fop;
396         int mode;
397 };
398
399 static struct rpc_filelist files[] = {
400         [RPCAUTH_lockd] = {
401                 .name = "lockd",
402                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
403         },
404         [RPCAUTH_mount] = {
405                 .name = "mount",
406                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
407         },
408         [RPCAUTH_nfs] = {
409                 .name = "nfs",
410                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
411         },
412         [RPCAUTH_portmap] = {
413                 .name = "portmap",
414                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
415         },
416         [RPCAUTH_statd] = {
417                 .name = "statd",
418                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
419         },
420 };
421
422 enum {
423         RPCAUTH_info = 2,
424         RPCAUTH_EOF
425 };
426
427 static struct rpc_filelist authfiles[] = {
428         [RPCAUTH_info] = {
429                 .name = "info",
430                 .i_fop = &rpc_info_operations,
431                 .mode = S_IFREG | S_IRUSR,
432         },
433 };
434
435 struct vfsmount *rpc_get_mount(void)
436 {
437         int err;
438
439         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
440         if (err != 0)
441                 return ERR_PTR(err);
442         return rpc_mount;
443 }
444
445 void rpc_put_mount(void)
446 {
447         simple_release_fs(&rpc_mount, &rpc_mount_count);
448 }
449
450 static int rpc_delete_dentry(struct dentry *dentry)
451 {
452         return 1;
453 }
454
455 static struct dentry_operations rpc_dentry_operations = {
456         .d_delete = rpc_delete_dentry,
457 };
458
459 static int
460 rpc_lookup_parent(char *path, struct nameidata *nd)
461 {
462         struct vfsmount *mnt;
463
464         if (path[0] == '\0')
465                 return -ENOENT;
466
467         mnt = rpc_get_mount();
468         if (IS_ERR(mnt)) {
469                 printk(KERN_WARNING "%s: %s failed to mount "
470                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
471                 return PTR_ERR(mnt);
472         }
473
474         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
475                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
476                                 __FILE__, __FUNCTION__, path);
477                 rpc_put_mount();
478                 return -ENOENT;
479         }
480         return 0;
481 }
482
483 static void
484 rpc_release_path(struct nameidata *nd)
485 {
486         path_release(nd);
487         rpc_put_mount();
488 }
489
490 static struct inode *
491 rpc_get_inode(struct super_block *sb, int mode)
492 {
493         struct inode *inode = new_inode(sb);
494         if (!inode)
495                 return NULL;
496         inode->i_mode = mode;
497         inode->i_uid = inode->i_gid = 0;
498         inode->i_blocks = 0;
499         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
500         switch(mode & S_IFMT) {
501                 case S_IFDIR:
502                         inode->i_fop = &simple_dir_operations;
503                         inode->i_op = &simple_dir_inode_operations;
504                         inc_nlink(inode);
505                 default:
506                         break;
507         }
508         return inode;
509 }
510
511 /*
512  * FIXME: This probably has races.
513  */
514 static void
515 rpc_depopulate(struct dentry *parent, int start, int eof)
516 {
517         struct inode *dir = parent->d_inode;
518         struct list_head *pos, *next;
519         struct dentry *dentry, *dvec[10];
520         int n = 0;
521
522         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
523 repeat:
524         spin_lock(&dcache_lock);
525         list_for_each_safe(pos, next, &parent->d_subdirs) {
526                 dentry = list_entry(pos, struct dentry, d_u.d_child);
527                 if (!dentry->d_inode ||
528                                 dentry->d_inode->i_ino < start ||
529                                 dentry->d_inode->i_ino >= eof)
530                         continue;
531                 spin_lock(&dentry->d_lock);
532                 if (!d_unhashed(dentry)) {
533                         dget_locked(dentry);
534                         __d_drop(dentry);
535                         spin_unlock(&dentry->d_lock);
536                         dvec[n++] = dentry;
537                         if (n == ARRAY_SIZE(dvec))
538                                 break;
539                 } else
540                         spin_unlock(&dentry->d_lock);
541         }
542         spin_unlock(&dcache_lock);
543         if (n) {
544                 do {
545                         dentry = dvec[--n];
546                         if (S_ISREG(dentry->d_inode->i_mode))
547                                 simple_unlink(dir, dentry);
548                         else if (S_ISDIR(dentry->d_inode->i_mode))
549                                 simple_rmdir(dir, dentry);
550                         d_delete(dentry);
551                         dput(dentry);
552                 } while (n);
553                 goto repeat;
554         }
555         mutex_unlock(&dir->i_mutex);
556 }
557
558 static int
559 rpc_populate(struct dentry *parent,
560                 struct rpc_filelist *files,
561                 int start, int eof)
562 {
563         struct inode *inode, *dir = parent->d_inode;
564         void *private = RPC_I(dir)->private;
565         struct dentry *dentry;
566         int mode, i;
567
568         mutex_lock(&dir->i_mutex);
569         for (i = start; i < eof; i++) {
570                 dentry = d_alloc_name(parent, files[i].name);
571                 if (!dentry)
572                         goto out_bad;
573                 dentry->d_op = &rpc_dentry_operations;
574                 mode = files[i].mode;
575                 inode = rpc_get_inode(dir->i_sb, mode);
576                 if (!inode) {
577                         dput(dentry);
578                         goto out_bad;
579                 }
580                 inode->i_ino = i;
581                 if (files[i].i_fop)
582                         inode->i_fop = files[i].i_fop;
583                 if (private)
584                         rpc_inode_setowner(inode, private);
585                 if (S_ISDIR(mode))
586                         inc_nlink(dir);
587                 d_add(dentry, inode);
588         }
589         mutex_unlock(&dir->i_mutex);
590         return 0;
591 out_bad:
592         mutex_unlock(&dir->i_mutex);
593         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
594                         __FILE__, __FUNCTION__, parent->d_name.name);
595         return -ENOMEM;
596 }
597
598 static int
599 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
600 {
601         struct inode *inode;
602
603         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
604         if (!inode)
605                 goto out_err;
606         inode->i_ino = iunique(dir->i_sb, 100);
607         d_instantiate(dentry, inode);
608         inc_nlink(dir);
609         inode_dir_notify(dir, DN_CREATE);
610         return 0;
611 out_err:
612         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
613                         __FILE__, __FUNCTION__, dentry->d_name.name);
614         return -ENOMEM;
615 }
616
617 static int
618 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
619 {
620         int error;
621         error = simple_rmdir(dir, dentry);
622         if (!error)
623                 d_delete(dentry);
624         return error;
625 }
626
627 static struct dentry *
628 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
629 {
630         struct inode *dir = parent->d_inode;
631         struct dentry *dentry;
632
633         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
634         dentry = lookup_one_len(name, parent, len);
635         if (IS_ERR(dentry))
636                 goto out_err;
637         if (!dentry->d_inode)
638                 dentry->d_op = &rpc_dentry_operations;
639         else if (exclusive) {
640                 dput(dentry);
641                 dentry = ERR_PTR(-EEXIST);
642                 goto out_err;
643         }
644         return dentry;
645 out_err:
646         mutex_unlock(&dir->i_mutex);
647         return dentry;
648 }
649
650 static struct dentry *
651 rpc_lookup_negative(char *path, struct nameidata *nd)
652 {
653         struct dentry *dentry;
654         int error;
655
656         if ((error = rpc_lookup_parent(path, nd)) != 0)
657                 return ERR_PTR(error);
658         dentry = rpc_lookup_create(nd->dentry, nd->last.name, nd->last.len, 1);
659         if (IS_ERR(dentry))
660                 rpc_release_path(nd);
661         return dentry;
662 }
663
664
665 struct dentry *
666 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
667 {
668         struct nameidata nd;
669         struct dentry *dentry;
670         struct inode *dir;
671         int error;
672
673         dentry = rpc_lookup_negative(path, &nd);
674         if (IS_ERR(dentry))
675                 return dentry;
676         dir = nd.dentry->d_inode;
677         if ((error = __rpc_mkdir(dir, dentry)) != 0)
678                 goto err_dput;
679         RPC_I(dentry->d_inode)->private = rpc_client;
680         error = rpc_populate(dentry, authfiles,
681                         RPCAUTH_info, RPCAUTH_EOF);
682         if (error)
683                 goto err_depopulate;
684         dget(dentry);
685 out:
686         mutex_unlock(&dir->i_mutex);
687         rpc_release_path(&nd);
688         return dentry;
689 err_depopulate:
690         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
691         __rpc_rmdir(dir, dentry);
692 err_dput:
693         dput(dentry);
694         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
695                         __FILE__, __FUNCTION__, path, error);
696         dentry = ERR_PTR(error);
697         goto out;
698 }
699
700 int
701 rpc_rmdir(struct dentry *dentry)
702 {
703         struct dentry *parent;
704         struct inode *dir;
705         int error;
706
707         parent = dget_parent(dentry);
708         dir = parent->d_inode;
709         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
710         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
711         error = __rpc_rmdir(dir, dentry);
712         dput(dentry);
713         mutex_unlock(&dir->i_mutex);
714         dput(parent);
715         return error;
716 }
717
718 struct dentry *
719 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
720 {
721         struct dentry *dentry;
722         struct inode *dir, *inode;
723         struct rpc_inode *rpci;
724
725         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
726         if (IS_ERR(dentry))
727                 return dentry;
728         dir = parent->d_inode;
729         if (dentry->d_inode) {
730                 rpci = RPC_I(dentry->d_inode);
731                 if (rpci->private != private ||
732                                 rpci->ops != ops ||
733                                 rpci->flags != flags) {
734                         dput (dentry);
735                         dentry = ERR_PTR(-EBUSY);
736                 }
737                 rpci->nkern_readwriters++;
738                 goto out;
739         }
740         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
741         if (!inode)
742                 goto err_dput;
743         inode->i_ino = iunique(dir->i_sb, 100);
744         inode->i_fop = &rpc_pipe_fops;
745         d_instantiate(dentry, inode);
746         rpci = RPC_I(inode);
747         rpci->private = private;
748         rpci->flags = flags;
749         rpci->ops = ops;
750         rpci->nkern_readwriters = 1;
751         inode_dir_notify(dir, DN_CREATE);
752         dget(dentry);
753 out:
754         mutex_unlock(&dir->i_mutex);
755         return dentry;
756 err_dput:
757         dput(dentry);
758         dentry = ERR_PTR(-ENOMEM);
759         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
760                         __FILE__, __FUNCTION__, parent->d_name.name, name,
761                         -ENOMEM);
762         goto out;
763 }
764
765 int
766 rpc_unlink(struct dentry *dentry)
767 {
768         struct dentry *parent;
769         struct inode *dir;
770         int error = 0;
771
772         parent = dget_parent(dentry);
773         dir = parent->d_inode;
774         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
775         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
776                 rpc_close_pipes(dentry->d_inode);
777                 error = simple_unlink(dir, dentry);
778                 if (!error)
779                         d_delete(dentry);
780         }
781         dput(dentry);
782         mutex_unlock(&dir->i_mutex);
783         dput(parent);
784         return error;
785 }
786
787 /*
788  * populate the filesystem
789  */
790 static struct super_operations s_ops = {
791         .alloc_inode    = rpc_alloc_inode,
792         .destroy_inode  = rpc_destroy_inode,
793         .statfs         = simple_statfs,
794 };
795
796 #define RPCAUTH_GSSMAGIC 0x67596969
797
798 static int
799 rpc_fill_super(struct super_block *sb, void *data, int silent)
800 {
801         struct inode *inode;
802         struct dentry *root;
803
804         sb->s_blocksize = PAGE_CACHE_SIZE;
805         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
806         sb->s_magic = RPCAUTH_GSSMAGIC;
807         sb->s_op = &s_ops;
808         sb->s_time_gran = 1;
809
810         inode = rpc_get_inode(sb, S_IFDIR | 0755);
811         if (!inode)
812                 return -ENOMEM;
813         root = d_alloc_root(inode);
814         if (!root) {
815                 iput(inode);
816                 return -ENOMEM;
817         }
818         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
819                 goto out;
820         sb->s_root = root;
821         return 0;
822 out:
823         d_genocide(root);
824         dput(root);
825         return -ENOMEM;
826 }
827
828 static int
829 rpc_get_sb(struct file_system_type *fs_type,
830                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
831 {
832         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
833 }
834
835 static struct file_system_type rpc_pipe_fs_type = {
836         .owner          = THIS_MODULE,
837         .name           = "rpc_pipefs",
838         .get_sb         = rpc_get_sb,
839         .kill_sb        = kill_litter_super,
840 };
841
842 static void
843 init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
844 {
845         struct rpc_inode *rpci = (struct rpc_inode *) foo;
846
847         inode_init_once(&rpci->vfs_inode);
848         rpci->private = NULL;
849         rpci->nreaders = 0;
850         rpci->nwriters = 0;
851         INIT_LIST_HEAD(&rpci->in_upcall);
852         INIT_LIST_HEAD(&rpci->in_downcall);
853         INIT_LIST_HEAD(&rpci->pipe);
854         rpci->pipelen = 0;
855         init_waitqueue_head(&rpci->waitq);
856         INIT_DELAYED_WORK(&rpci->queue_timeout,
857                             rpc_timeout_upcall_queue);
858         rpci->ops = NULL;
859 }
860
861 int register_rpc_pipefs(void)
862 {
863         int err;
864
865         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
866                                 sizeof(struct rpc_inode),
867                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
868                                                 SLAB_MEM_SPREAD),
869                                 init_once);
870         if (!rpc_inode_cachep)
871                 return -ENOMEM;
872         err = register_filesystem(&rpc_pipe_fs_type);
873         if (err) {
874                 kmem_cache_destroy(rpc_inode_cachep);
875                 return err;
876         }
877
878         return 0;
879 }
880
881 void unregister_rpc_pipefs(void)
882 {
883         kmem_cache_destroy(rpc_inode_cachep);
884         unregister_filesystem(&rpc_pipe_fs_type);
885 }