Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[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(&rpci->queue_timeout);
136                 flush_workqueue(rpciod_workqueue);
137         }
138         rpc_inode_setowner(inode, NULL);
139         mutex_unlock(&inode->i_mutex);
140 }
141
142 static struct inode *
143 rpc_alloc_inode(struct super_block *sb)
144 {
145         struct rpc_inode *rpci;
146         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
147         if (!rpci)
148                 return NULL;
149         return &rpci->vfs_inode;
150 }
151
152 static void
153 rpc_destroy_inode(struct inode *inode)
154 {
155         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
156 }
157
158 static int
159 rpc_pipe_open(struct inode *inode, struct file *filp)
160 {
161         struct rpc_inode *rpci = RPC_I(inode);
162         int res = -ENXIO;
163
164         mutex_lock(&inode->i_mutex);
165         if (rpci->ops != NULL) {
166                 if (filp->f_mode & FMODE_READ)
167                         rpci->nreaders ++;
168                 if (filp->f_mode & FMODE_WRITE)
169                         rpci->nwriters ++;
170                 res = 0;
171         }
172         mutex_unlock(&inode->i_mutex);
173         return res;
174 }
175
176 static int
177 rpc_pipe_release(struct inode *inode, struct file *filp)
178 {
179         struct rpc_inode *rpci = RPC_I(inode);
180         struct rpc_pipe_msg *msg;
181
182         mutex_lock(&inode->i_mutex);
183         if (rpci->ops == NULL)
184                 goto out;
185         msg = (struct rpc_pipe_msg *)filp->private_data;
186         if (msg != NULL) {
187                 spin_lock(&inode->i_lock);
188                 msg->errno = -EAGAIN;
189                 list_del(&msg->list);
190                 spin_unlock(&inode->i_lock);
191                 rpci->ops->destroy_msg(msg);
192         }
193         if (filp->f_mode & FMODE_WRITE)
194                 rpci->nwriters --;
195         if (filp->f_mode & FMODE_READ) {
196                 rpci->nreaders --;
197                 if (rpci->nreaders == 0) {
198                         LIST_HEAD(free_list);
199                         spin_lock(&inode->i_lock);
200                         list_splice_init(&rpci->pipe, &free_list);
201                         rpci->pipelen = 0;
202                         spin_unlock(&inode->i_lock);
203                         rpc_purge_list(rpci, &free_list,
204                                         rpci->ops->destroy_msg, -EAGAIN);
205                 }
206         }
207         if (rpci->ops->release_pipe)
208                 rpci->ops->release_pipe(inode);
209 out:
210         mutex_unlock(&inode->i_mutex);
211         return 0;
212 }
213
214 static ssize_t
215 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
216 {
217         struct inode *inode = filp->f_path.dentry->d_inode;
218         struct rpc_inode *rpci = RPC_I(inode);
219         struct rpc_pipe_msg *msg;
220         int res = 0;
221
222         mutex_lock(&inode->i_mutex);
223         if (rpci->ops == NULL) {
224                 res = -EPIPE;
225                 goto out_unlock;
226         }
227         msg = filp->private_data;
228         if (msg == NULL) {
229                 spin_lock(&inode->i_lock);
230                 if (!list_empty(&rpci->pipe)) {
231                         msg = list_entry(rpci->pipe.next,
232                                         struct rpc_pipe_msg,
233                                         list);
234                         list_move(&msg->list, &rpci->in_upcall);
235                         rpci->pipelen -= msg->len;
236                         filp->private_data = msg;
237                         msg->copied = 0;
238                 }
239                 spin_unlock(&inode->i_lock);
240                 if (msg == NULL)
241                         goto out_unlock;
242         }
243         /* NOTE: it is up to the callback to update msg->copied */
244         res = rpci->ops->upcall(filp, msg, buf, len);
245         if (res < 0 || msg->len == msg->copied) {
246                 filp->private_data = NULL;
247                 spin_lock(&inode->i_lock);
248                 list_del(&msg->list);
249                 spin_unlock(&inode->i_lock);
250                 rpci->ops->destroy_msg(msg);
251         }
252 out_unlock:
253         mutex_unlock(&inode->i_mutex);
254         return res;
255 }
256
257 static ssize_t
258 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
259 {
260         struct inode *inode = filp->f_path.dentry->d_inode;
261         struct rpc_inode *rpci = RPC_I(inode);
262         int res;
263
264         mutex_lock(&inode->i_mutex);
265         res = -EPIPE;
266         if (rpci->ops != NULL)
267                 res = rpci->ops->downcall(filp, buf, len);
268         mutex_unlock(&inode->i_mutex);
269         return res;
270 }
271
272 static unsigned int
273 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
274 {
275         struct rpc_inode *rpci;
276         unsigned int mask = 0;
277
278         rpci = RPC_I(filp->f_path.dentry->d_inode);
279         poll_wait(filp, &rpci->waitq, wait);
280
281         mask = POLLOUT | POLLWRNORM;
282         if (rpci->ops == NULL)
283                 mask |= POLLERR | POLLHUP;
284         if (!list_empty(&rpci->pipe))
285                 mask |= POLLIN | POLLRDNORM;
286         return mask;
287 }
288
289 static int
290 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
291                 unsigned int cmd, unsigned long arg)
292 {
293         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
294         int len;
295
296         switch (cmd) {
297         case FIONREAD:
298                 if (rpci->ops == NULL)
299                         return -EPIPE;
300                 len = rpci->pipelen;
301                 if (filp->private_data) {
302                         struct rpc_pipe_msg *msg;
303                         msg = (struct rpc_pipe_msg *)filp->private_data;
304                         len += msg->len - msg->copied;
305                 }
306                 return put_user(len, (int __user *)arg);
307         default:
308                 return -EINVAL;
309         }
310 }
311
312 static const struct file_operations rpc_pipe_fops = {
313         .owner          = THIS_MODULE,
314         .llseek         = no_llseek,
315         .read           = rpc_pipe_read,
316         .write          = rpc_pipe_write,
317         .poll           = rpc_pipe_poll,
318         .ioctl          = rpc_pipe_ioctl,
319         .open           = rpc_pipe_open,
320         .release        = rpc_pipe_release,
321 };
322
323 static int
324 rpc_show_info(struct seq_file *m, void *v)
325 {
326         struct rpc_clnt *clnt = m->private;
327
328         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
329         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
330                         clnt->cl_prog, clnt->cl_vers);
331         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
332         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
333         return 0;
334 }
335
336 static int
337 rpc_info_open(struct inode *inode, struct file *file)
338 {
339         struct rpc_clnt *clnt;
340         int ret = single_open(file, rpc_show_info, NULL);
341
342         if (!ret) {
343                 struct seq_file *m = file->private_data;
344                 mutex_lock(&inode->i_mutex);
345                 clnt = RPC_I(inode)->private;
346                 if (clnt) {
347                         kref_get(&clnt->cl_kref);
348                         m->private = clnt;
349                 } else {
350                         single_release(inode, file);
351                         ret = -EINVAL;
352                 }
353                 mutex_unlock(&inode->i_mutex);
354         }
355         return ret;
356 }
357
358 static int
359 rpc_info_release(struct inode *inode, struct file *file)
360 {
361         struct seq_file *m = file->private_data;
362         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
363
364         if (clnt)
365                 rpc_release_client(clnt);
366         return single_release(inode, file);
367 }
368
369 static const struct file_operations rpc_info_operations = {
370         .owner          = THIS_MODULE,
371         .open           = rpc_info_open,
372         .read           = seq_read,
373         .llseek         = seq_lseek,
374         .release        = rpc_info_release,
375 };
376
377
378 /*
379  * We have a single directory with 1 node in it.
380  */
381 enum {
382         RPCAUTH_Root = 1,
383         RPCAUTH_lockd,
384         RPCAUTH_mount,
385         RPCAUTH_nfs,
386         RPCAUTH_portmap,
387         RPCAUTH_statd,
388         RPCAUTH_RootEOF
389 };
390
391 /*
392  * Description of fs contents.
393  */
394 struct rpc_filelist {
395         char *name;
396         const struct file_operations *i_fop;
397         int mode;
398 };
399
400 static struct rpc_filelist files[] = {
401         [RPCAUTH_lockd] = {
402                 .name = "lockd",
403                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
404         },
405         [RPCAUTH_mount] = {
406                 .name = "mount",
407                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
408         },
409         [RPCAUTH_nfs] = {
410                 .name = "nfs",
411                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
412         },
413         [RPCAUTH_portmap] = {
414                 .name = "portmap",
415                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
416         },
417         [RPCAUTH_statd] = {
418                 .name = "statd",
419                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
420         },
421 };
422
423 enum {
424         RPCAUTH_info = 2,
425         RPCAUTH_EOF
426 };
427
428 static struct rpc_filelist authfiles[] = {
429         [RPCAUTH_info] = {
430                 .name = "info",
431                 .i_fop = &rpc_info_operations,
432                 .mode = S_IFREG | S_IRUSR,
433         },
434 };
435
436 struct vfsmount *rpc_get_mount(void)
437 {
438         int err;
439
440         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
441         if (err != 0)
442                 return ERR_PTR(err);
443         return rpc_mount;
444 }
445
446 void rpc_put_mount(void)
447 {
448         simple_release_fs(&rpc_mount, &rpc_mount_count);
449 }
450
451 static int rpc_delete_dentry(struct dentry *dentry)
452 {
453         return 1;
454 }
455
456 static struct dentry_operations rpc_dentry_operations = {
457         .d_delete = rpc_delete_dentry,
458 };
459
460 static int
461 rpc_lookup_parent(char *path, struct nameidata *nd)
462 {
463         struct vfsmount *mnt;
464
465         if (path[0] == '\0')
466                 return -ENOENT;
467
468         mnt = rpc_get_mount();
469         if (IS_ERR(mnt)) {
470                 printk(KERN_WARNING "%s: %s failed to mount "
471                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
472                 return PTR_ERR(mnt);
473         }
474
475         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
476                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
477                                 __FILE__, __FUNCTION__, path);
478                 rpc_put_mount();
479                 return -ENOENT;
480         }
481         return 0;
482 }
483
484 static void
485 rpc_release_path(struct nameidata *nd)
486 {
487         path_release(nd);
488         rpc_put_mount();
489 }
490
491 static struct inode *
492 rpc_get_inode(struct super_block *sb, int mode)
493 {
494         struct inode *inode = new_inode(sb);
495         if (!inode)
496                 return NULL;
497         inode->i_mode = mode;
498         inode->i_uid = inode->i_gid = 0;
499         inode->i_blocks = 0;
500         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
501         switch(mode & S_IFMT) {
502                 case S_IFDIR:
503                         inode->i_fop = &simple_dir_operations;
504                         inode->i_op = &simple_dir_inode_operations;
505                         inc_nlink(inode);
506                 default:
507                         break;
508         }
509         return inode;
510 }
511
512 /*
513  * FIXME: This probably has races.
514  */
515 static void
516 rpc_depopulate(struct dentry *parent, int start, int eof)
517 {
518         struct inode *dir = parent->d_inode;
519         struct list_head *pos, *next;
520         struct dentry *dentry, *dvec[10];
521         int n = 0;
522
523         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
524 repeat:
525         spin_lock(&dcache_lock);
526         list_for_each_safe(pos, next, &parent->d_subdirs) {
527                 dentry = list_entry(pos, struct dentry, d_u.d_child);
528                 if (!dentry->d_inode ||
529                                 dentry->d_inode->i_ino < start ||
530                                 dentry->d_inode->i_ino >= eof)
531                         continue;
532                 spin_lock(&dentry->d_lock);
533                 if (!d_unhashed(dentry)) {
534                         dget_locked(dentry);
535                         __d_drop(dentry);
536                         spin_unlock(&dentry->d_lock);
537                         dvec[n++] = dentry;
538                         if (n == ARRAY_SIZE(dvec))
539                                 break;
540                 } else
541                         spin_unlock(&dentry->d_lock);
542         }
543         spin_unlock(&dcache_lock);
544         if (n) {
545                 do {
546                         dentry = dvec[--n];
547                         if (S_ISREG(dentry->d_inode->i_mode))
548                                 simple_unlink(dir, dentry);
549                         else if (S_ISDIR(dentry->d_inode->i_mode))
550                                 simple_rmdir(dir, dentry);
551                         d_delete(dentry);
552                         dput(dentry);
553                 } while (n);
554                 goto repeat;
555         }
556         mutex_unlock(&dir->i_mutex);
557 }
558
559 static int
560 rpc_populate(struct dentry *parent,
561                 struct rpc_filelist *files,
562                 int start, int eof)
563 {
564         struct inode *inode, *dir = parent->d_inode;
565         void *private = RPC_I(dir)->private;
566         struct dentry *dentry;
567         int mode, i;
568
569         mutex_lock(&dir->i_mutex);
570         for (i = start; i < eof; i++) {
571                 dentry = d_alloc_name(parent, files[i].name);
572                 if (!dentry)
573                         goto out_bad;
574                 dentry->d_op = &rpc_dentry_operations;
575                 mode = files[i].mode;
576                 inode = rpc_get_inode(dir->i_sb, mode);
577                 if (!inode) {
578                         dput(dentry);
579                         goto out_bad;
580                 }
581                 inode->i_ino = i;
582                 if (files[i].i_fop)
583                         inode->i_fop = files[i].i_fop;
584                 if (private)
585                         rpc_inode_setowner(inode, private);
586                 if (S_ISDIR(mode))
587                         inc_nlink(dir);
588                 d_add(dentry, inode);
589         }
590         mutex_unlock(&dir->i_mutex);
591         return 0;
592 out_bad:
593         mutex_unlock(&dir->i_mutex);
594         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
595                         __FILE__, __FUNCTION__, parent->d_name.name);
596         return -ENOMEM;
597 }
598
599 static int
600 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
601 {
602         struct inode *inode;
603
604         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
605         if (!inode)
606                 goto out_err;
607         inode->i_ino = iunique(dir->i_sb, 100);
608         d_instantiate(dentry, inode);
609         inc_nlink(dir);
610         inode_dir_notify(dir, DN_CREATE);
611         return 0;
612 out_err:
613         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
614                         __FILE__, __FUNCTION__, dentry->d_name.name);
615         return -ENOMEM;
616 }
617
618 static int
619 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
620 {
621         int error;
622         error = simple_rmdir(dir, dentry);
623         if (!error)
624                 d_delete(dentry);
625         return error;
626 }
627
628 static struct dentry *
629 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
630 {
631         struct inode *dir = parent->d_inode;
632         struct dentry *dentry;
633
634         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
635         dentry = lookup_one_len(name, parent, len);
636         if (IS_ERR(dentry))
637                 goto out_err;
638         if (!dentry->d_inode)
639                 dentry->d_op = &rpc_dentry_operations;
640         else if (exclusive) {
641                 dput(dentry);
642                 dentry = ERR_PTR(-EEXIST);
643                 goto out_err;
644         }
645         return dentry;
646 out_err:
647         mutex_unlock(&dir->i_mutex);
648         return dentry;
649 }
650
651 static struct dentry *
652 rpc_lookup_negative(char *path, struct nameidata *nd)
653 {
654         struct dentry *dentry;
655         int error;
656
657         if ((error = rpc_lookup_parent(path, nd)) != 0)
658                 return ERR_PTR(error);
659         dentry = rpc_lookup_create(nd->dentry, nd->last.name, nd->last.len, 1);
660         if (IS_ERR(dentry))
661                 rpc_release_path(nd);
662         return dentry;
663 }
664
665
666 struct dentry *
667 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
668 {
669         struct nameidata nd;
670         struct dentry *dentry;
671         struct inode *dir;
672         int error;
673
674         dentry = rpc_lookup_negative(path, &nd);
675         if (IS_ERR(dentry))
676                 return dentry;
677         dir = nd.dentry->d_inode;
678         if ((error = __rpc_mkdir(dir, dentry)) != 0)
679                 goto err_dput;
680         RPC_I(dentry->d_inode)->private = rpc_client;
681         error = rpc_populate(dentry, authfiles,
682                         RPCAUTH_info, RPCAUTH_EOF);
683         if (error)
684                 goto err_depopulate;
685         dget(dentry);
686 out:
687         mutex_unlock(&dir->i_mutex);
688         rpc_release_path(&nd);
689         return dentry;
690 err_depopulate:
691         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
692         __rpc_rmdir(dir, dentry);
693 err_dput:
694         dput(dentry);
695         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
696                         __FILE__, __FUNCTION__, path, error);
697         dentry = ERR_PTR(error);
698         goto out;
699 }
700
701 int
702 rpc_rmdir(struct dentry *dentry)
703 {
704         struct dentry *parent;
705         struct inode *dir;
706         int error;
707
708         parent = dget_parent(dentry);
709         dir = parent->d_inode;
710         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
711         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
712         error = __rpc_rmdir(dir, dentry);
713         dput(dentry);
714         mutex_unlock(&dir->i_mutex);
715         dput(parent);
716         return error;
717 }
718
719 struct dentry *
720 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
721 {
722         struct dentry *dentry;
723         struct inode *dir, *inode;
724         struct rpc_inode *rpci;
725
726         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
727         if (IS_ERR(dentry))
728                 return dentry;
729         dir = parent->d_inode;
730         if (dentry->d_inode) {
731                 rpci = RPC_I(dentry->d_inode);
732                 if (rpci->private != private ||
733                                 rpci->ops != ops ||
734                                 rpci->flags != flags) {
735                         dput (dentry);
736                         dentry = ERR_PTR(-EBUSY);
737                 }
738                 rpci->nkern_readwriters++;
739                 goto out;
740         }
741         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
742         if (!inode)
743                 goto err_dput;
744         inode->i_ino = iunique(dir->i_sb, 100);
745         inode->i_fop = &rpc_pipe_fops;
746         d_instantiate(dentry, inode);
747         rpci = RPC_I(inode);
748         rpci->private = private;
749         rpci->flags = flags;
750         rpci->ops = ops;
751         rpci->nkern_readwriters = 1;
752         inode_dir_notify(dir, DN_CREATE);
753         dget(dentry);
754 out:
755         mutex_unlock(&dir->i_mutex);
756         return dentry;
757 err_dput:
758         dput(dentry);
759         dentry = ERR_PTR(-ENOMEM);
760         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
761                         __FILE__, __FUNCTION__, parent->d_name.name, name,
762                         -ENOMEM);
763         goto out;
764 }
765
766 int
767 rpc_unlink(struct dentry *dentry)
768 {
769         struct dentry *parent;
770         struct inode *dir;
771         int error = 0;
772
773         parent = dget_parent(dentry);
774         dir = parent->d_inode;
775         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
776         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
777                 rpc_close_pipes(dentry->d_inode);
778                 error = simple_unlink(dir, dentry);
779                 if (!error)
780                         d_delete(dentry);
781         }
782         dput(dentry);
783         mutex_unlock(&dir->i_mutex);
784         dput(parent);
785         return error;
786 }
787
788 /*
789  * populate the filesystem
790  */
791 static struct super_operations s_ops = {
792         .alloc_inode    = rpc_alloc_inode,
793         .destroy_inode  = rpc_destroy_inode,
794         .statfs         = simple_statfs,
795 };
796
797 #define RPCAUTH_GSSMAGIC 0x67596969
798
799 static int
800 rpc_fill_super(struct super_block *sb, void *data, int silent)
801 {
802         struct inode *inode;
803         struct dentry *root;
804
805         sb->s_blocksize = PAGE_CACHE_SIZE;
806         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
807         sb->s_magic = RPCAUTH_GSSMAGIC;
808         sb->s_op = &s_ops;
809         sb->s_time_gran = 1;
810
811         inode = rpc_get_inode(sb, S_IFDIR | 0755);
812         if (!inode)
813                 return -ENOMEM;
814         root = d_alloc_root(inode);
815         if (!root) {
816                 iput(inode);
817                 return -ENOMEM;
818         }
819         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
820                 goto out;
821         sb->s_root = root;
822         return 0;
823 out:
824         d_genocide(root);
825         dput(root);
826         return -ENOMEM;
827 }
828
829 static int
830 rpc_get_sb(struct file_system_type *fs_type,
831                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
832 {
833         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
834 }
835
836 static struct file_system_type rpc_pipe_fs_type = {
837         .owner          = THIS_MODULE,
838         .name           = "rpc_pipefs",
839         .get_sb         = rpc_get_sb,
840         .kill_sb        = kill_litter_super,
841 };
842
843 static void
844 init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
845 {
846         struct rpc_inode *rpci = (struct rpc_inode *) foo;
847
848         inode_init_once(&rpci->vfs_inode);
849         rpci->private = NULL;
850         rpci->nreaders = 0;
851         rpci->nwriters = 0;
852         INIT_LIST_HEAD(&rpci->in_upcall);
853         INIT_LIST_HEAD(&rpci->in_downcall);
854         INIT_LIST_HEAD(&rpci->pipe);
855         rpci->pipelen = 0;
856         init_waitqueue_head(&rpci->waitq);
857         INIT_DELAYED_WORK(&rpci->queue_timeout,
858                             rpc_timeout_upcall_queue);
859         rpci->ops = NULL;
860 }
861
862 int register_rpc_pipefs(void)
863 {
864         int err;
865
866         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
867                                 sizeof(struct rpc_inode),
868                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
869                                                 SLAB_MEM_SPREAD),
870                                 init_once);
871         if (!rpc_inode_cachep)
872                 return -ENOMEM;
873         err = register_filesystem(&rpc_pipe_fs_type);
874         if (err) {
875                 kmem_cache_destroy(rpc_inode_cachep);
876                 return err;
877         }
878
879         return 0;
880 }
881
882 void unregister_rpc_pipefs(void)
883 {
884         kmem_cache_destroy(rpc_inode_cachep);
885         unregister_filesystem(&rpc_pipe_fs_type);
886 }