xref: /linux/net/sunrpc/rpc_pipe.c (revision 858259cf7d1c443c836a2022b78cb281f0a9b95e)
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/config.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/string.h>
15 #include <linux/pagemap.h>
16 #include <linux/mount.h>
17 #include <linux/namei.h>
18 #include <linux/dnotify.h>
19 #include <linux/kernel.h>
20 
21 #include <asm/ioctls.h>
22 #include <linux/fs.h>
23 #include <linux/poll.h>
24 #include <linux/wait.h>
25 #include <linux/seq_file.h>
26 
27 #include <linux/sunrpc/clnt.h>
28 #include <linux/workqueue.h>
29 #include <linux/sunrpc/rpc_pipe_fs.h>
30 
31 static struct vfsmount *rpc_mount __read_mostly;
32 static int rpc_mount_count;
33 
34 static struct file_system_type rpc_pipe_fs_type;
35 
36 
37 static kmem_cache_t *rpc_inode_cachep __read_mostly;
38 
39 #define RPC_UPCALL_TIMEOUT (30*HZ)
40 
41 static void
42 __rpc_purge_upcall(struct inode *inode, int err)
43 {
44 	struct rpc_inode *rpci = RPC_I(inode);
45 	struct rpc_pipe_msg *msg;
46 
47 	while (!list_empty(&rpci->pipe)) {
48 		msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
49 		list_del_init(&msg->list);
50 		msg->errno = err;
51 		rpci->ops->destroy_msg(msg);
52 	}
53 	while (!list_empty(&rpci->in_upcall)) {
54 		msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
55 		list_del_init(&msg->list);
56 		msg->errno = err;
57 		rpci->ops->destroy_msg(msg);
58 	}
59 	rpci->pipelen = 0;
60 	wake_up(&rpci->waitq);
61 }
62 
63 static void
64 rpc_timeout_upcall_queue(void *data)
65 {
66 	struct rpc_inode *rpci = (struct rpc_inode *)data;
67 	struct inode *inode = &rpci->vfs_inode;
68 
69 	down(&inode->i_sem);
70 	if (rpci->nreaders == 0 && !list_empty(&rpci->pipe))
71 		__rpc_purge_upcall(inode, -ETIMEDOUT);
72 	up(&inode->i_sem);
73 }
74 
75 int
76 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
77 {
78 	struct rpc_inode *rpci = RPC_I(inode);
79 	int res = -EPIPE;
80 
81 	down(&inode->i_sem);
82 	if (rpci->ops == NULL)
83 		goto out;
84 	if (rpci->nreaders) {
85 		list_add_tail(&msg->list, &rpci->pipe);
86 		rpci->pipelen += msg->len;
87 		res = 0;
88 	} else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
89 		if (list_empty(&rpci->pipe))
90 			schedule_delayed_work(&rpci->queue_timeout,
91 					RPC_UPCALL_TIMEOUT);
92 		list_add_tail(&msg->list, &rpci->pipe);
93 		rpci->pipelen += msg->len;
94 		res = 0;
95 	}
96 out:
97 	up(&inode->i_sem);
98 	wake_up(&rpci->waitq);
99 	return res;
100 }
101 
102 static inline void
103 rpc_inode_setowner(struct inode *inode, void *private)
104 {
105 	RPC_I(inode)->private = private;
106 }
107 
108 static void
109 rpc_close_pipes(struct inode *inode)
110 {
111 	struct rpc_inode *rpci = RPC_I(inode);
112 
113 	cancel_delayed_work(&rpci->queue_timeout);
114 	flush_scheduled_work();
115 	down(&inode->i_sem);
116 	if (rpci->ops != NULL) {
117 		rpci->nreaders = 0;
118 		__rpc_purge_upcall(inode, -EPIPE);
119 		rpci->nwriters = 0;
120 		if (rpci->ops->release_pipe)
121 			rpci->ops->release_pipe(inode);
122 		rpci->ops = NULL;
123 	}
124 	rpc_inode_setowner(inode, NULL);
125 	up(&inode->i_sem);
126 }
127 
128 static struct inode *
129 rpc_alloc_inode(struct super_block *sb)
130 {
131 	struct rpc_inode *rpci;
132 	rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, SLAB_KERNEL);
133 	if (!rpci)
134 		return NULL;
135 	return &rpci->vfs_inode;
136 }
137 
138 static void
139 rpc_destroy_inode(struct inode *inode)
140 {
141 	kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
142 }
143 
144 static int
145 rpc_pipe_open(struct inode *inode, struct file *filp)
146 {
147 	struct rpc_inode *rpci = RPC_I(inode);
148 	int res = -ENXIO;
149 
150 	down(&inode->i_sem);
151 	if (rpci->ops != NULL) {
152 		if (filp->f_mode & FMODE_READ)
153 			rpci->nreaders ++;
154 		if (filp->f_mode & FMODE_WRITE)
155 			rpci->nwriters ++;
156 		res = 0;
157 	}
158 	up(&inode->i_sem);
159 	return res;
160 }
161 
162 static int
163 rpc_pipe_release(struct inode *inode, struct file *filp)
164 {
165 	struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
166 	struct rpc_pipe_msg *msg;
167 
168 	down(&inode->i_sem);
169 	if (rpci->ops == NULL)
170 		goto out;
171 	msg = (struct rpc_pipe_msg *)filp->private_data;
172 	if (msg != NULL) {
173 		msg->errno = -EPIPE;
174 		list_del_init(&msg->list);
175 		rpci->ops->destroy_msg(msg);
176 	}
177 	if (filp->f_mode & FMODE_WRITE)
178 		rpci->nwriters --;
179 	if (filp->f_mode & FMODE_READ)
180 		rpci->nreaders --;
181 	if (!rpci->nreaders)
182 		__rpc_purge_upcall(inode, -EPIPE);
183 	if (rpci->ops->release_pipe)
184 		rpci->ops->release_pipe(inode);
185 out:
186 	up(&inode->i_sem);
187 	return 0;
188 }
189 
190 static ssize_t
191 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
192 {
193 	struct inode *inode = filp->f_dentry->d_inode;
194 	struct rpc_inode *rpci = RPC_I(inode);
195 	struct rpc_pipe_msg *msg;
196 	int res = 0;
197 
198 	down(&inode->i_sem);
199 	if (rpci->ops == NULL) {
200 		res = -EPIPE;
201 		goto out_unlock;
202 	}
203 	msg = filp->private_data;
204 	if (msg == NULL) {
205 		if (!list_empty(&rpci->pipe)) {
206 			msg = list_entry(rpci->pipe.next,
207 					struct rpc_pipe_msg,
208 					list);
209 			list_move(&msg->list, &rpci->in_upcall);
210 			rpci->pipelen -= msg->len;
211 			filp->private_data = msg;
212 			msg->copied = 0;
213 		}
214 		if (msg == NULL)
215 			goto out_unlock;
216 	}
217 	/* NOTE: it is up to the callback to update msg->copied */
218 	res = rpci->ops->upcall(filp, msg, buf, len);
219 	if (res < 0 || msg->len == msg->copied) {
220 		filp->private_data = NULL;
221 		list_del_init(&msg->list);
222 		rpci->ops->destroy_msg(msg);
223 	}
224 out_unlock:
225 	up(&inode->i_sem);
226 	return res;
227 }
228 
229 static ssize_t
230 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
231 {
232 	struct inode *inode = filp->f_dentry->d_inode;
233 	struct rpc_inode *rpci = RPC_I(inode);
234 	int res;
235 
236 	down(&inode->i_sem);
237 	res = -EPIPE;
238 	if (rpci->ops != NULL)
239 		res = rpci->ops->downcall(filp, buf, len);
240 	up(&inode->i_sem);
241 	return res;
242 }
243 
244 static unsigned int
245 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
246 {
247 	struct rpc_inode *rpci;
248 	unsigned int mask = 0;
249 
250 	rpci = RPC_I(filp->f_dentry->d_inode);
251 	poll_wait(filp, &rpci->waitq, wait);
252 
253 	mask = POLLOUT | POLLWRNORM;
254 	if (rpci->ops == NULL)
255 		mask |= POLLERR | POLLHUP;
256 	if (!list_empty(&rpci->pipe))
257 		mask |= POLLIN | POLLRDNORM;
258 	return mask;
259 }
260 
261 static int
262 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
263 		unsigned int cmd, unsigned long arg)
264 {
265 	struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
266 	int len;
267 
268 	switch (cmd) {
269 	case FIONREAD:
270 		if (rpci->ops == NULL)
271 			return -EPIPE;
272 		len = rpci->pipelen;
273 		if (filp->private_data) {
274 			struct rpc_pipe_msg *msg;
275 			msg = (struct rpc_pipe_msg *)filp->private_data;
276 			len += msg->len - msg->copied;
277 		}
278 		return put_user(len, (int __user *)arg);
279 	default:
280 		return -EINVAL;
281 	}
282 }
283 
284 static struct file_operations rpc_pipe_fops = {
285 	.owner		= THIS_MODULE,
286 	.llseek		= no_llseek,
287 	.read		= rpc_pipe_read,
288 	.write		= rpc_pipe_write,
289 	.poll		= rpc_pipe_poll,
290 	.ioctl		= rpc_pipe_ioctl,
291 	.open		= rpc_pipe_open,
292 	.release	= rpc_pipe_release,
293 };
294 
295 static int
296 rpc_show_info(struct seq_file *m, void *v)
297 {
298 	struct rpc_clnt *clnt = m->private;
299 
300 	seq_printf(m, "RPC server: %s\n", clnt->cl_server);
301 	seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
302 			clnt->cl_prog, clnt->cl_vers);
303 	seq_printf(m, "address: %u.%u.%u.%u\n",
304 			NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
305 	seq_printf(m, "protocol: %s\n",
306 			clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
307 	return 0;
308 }
309 
310 static int
311 rpc_info_open(struct inode *inode, struct file *file)
312 {
313 	struct rpc_clnt *clnt;
314 	int ret = single_open(file, rpc_show_info, NULL);
315 
316 	if (!ret) {
317 		struct seq_file *m = file->private_data;
318 		down(&inode->i_sem);
319 		clnt = RPC_I(inode)->private;
320 		if (clnt) {
321 			atomic_inc(&clnt->cl_users);
322 			m->private = clnt;
323 		} else {
324 			single_release(inode, file);
325 			ret = -EINVAL;
326 		}
327 		up(&inode->i_sem);
328 	}
329 	return ret;
330 }
331 
332 static int
333 rpc_info_release(struct inode *inode, struct file *file)
334 {
335 	struct seq_file *m = file->private_data;
336 	struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
337 
338 	if (clnt)
339 		rpc_release_client(clnt);
340 	return single_release(inode, file);
341 }
342 
343 static struct file_operations rpc_info_operations = {
344 	.owner		= THIS_MODULE,
345 	.open		= rpc_info_open,
346 	.read		= seq_read,
347 	.llseek		= seq_lseek,
348 	.release	= rpc_info_release,
349 };
350 
351 
352 /*
353  * We have a single directory with 1 node in it.
354  */
355 enum {
356 	RPCAUTH_Root = 1,
357 	RPCAUTH_lockd,
358 	RPCAUTH_mount,
359 	RPCAUTH_nfs,
360 	RPCAUTH_portmap,
361 	RPCAUTH_statd,
362 	RPCAUTH_RootEOF
363 };
364 
365 /*
366  * Description of fs contents.
367  */
368 struct rpc_filelist {
369 	char *name;
370 	struct file_operations *i_fop;
371 	int mode;
372 };
373 
374 static struct rpc_filelist files[] = {
375 	[RPCAUTH_lockd] = {
376 		.name = "lockd",
377 		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
378 	},
379 	[RPCAUTH_mount] = {
380 		.name = "mount",
381 		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
382 	},
383 	[RPCAUTH_nfs] = {
384 		.name = "nfs",
385 		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
386 	},
387 	[RPCAUTH_portmap] = {
388 		.name = "portmap",
389 		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
390 	},
391 	[RPCAUTH_statd] = {
392 		.name = "statd",
393 		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
394 	},
395 };
396 
397 enum {
398 	RPCAUTH_info = 2,
399 	RPCAUTH_EOF
400 };
401 
402 static struct rpc_filelist authfiles[] = {
403 	[RPCAUTH_info] = {
404 		.name = "info",
405 		.i_fop = &rpc_info_operations,
406 		.mode = S_IFREG | S_IRUSR,
407 	},
408 };
409 
410 static int
411 rpc_get_mount(void)
412 {
413 	return simple_pin_fs("rpc_pipefs", &rpc_mount, &rpc_mount_count);
414 }
415 
416 static void
417 rpc_put_mount(void)
418 {
419 	simple_release_fs(&rpc_mount, &rpc_mount_count);
420 }
421 
422 static int
423 rpc_lookup_parent(char *path, struct nameidata *nd)
424 {
425 	if (path[0] == '\0')
426 		return -ENOENT;
427 	if (rpc_get_mount()) {
428 		printk(KERN_WARNING "%s: %s failed to mount "
429 			       "pseudofilesystem \n", __FILE__, __FUNCTION__);
430 		return -ENODEV;
431 	}
432 	nd->mnt = mntget(rpc_mount);
433 	nd->dentry = dget(rpc_mount->mnt_root);
434 	nd->last_type = LAST_ROOT;
435 	nd->flags = LOOKUP_PARENT;
436 	nd->depth = 0;
437 
438 	if (path_walk(path, nd)) {
439 		printk(KERN_WARNING "%s: %s failed to find path %s\n",
440 				__FILE__, __FUNCTION__, path);
441 		rpc_put_mount();
442 		return -ENOENT;
443 	}
444 	return 0;
445 }
446 
447 static void
448 rpc_release_path(struct nameidata *nd)
449 {
450 	path_release(nd);
451 	rpc_put_mount();
452 }
453 
454 static struct inode *
455 rpc_get_inode(struct super_block *sb, int mode)
456 {
457 	struct inode *inode = new_inode(sb);
458 	if (!inode)
459 		return NULL;
460 	inode->i_mode = mode;
461 	inode->i_uid = inode->i_gid = 0;
462 	inode->i_blksize = PAGE_CACHE_SIZE;
463 	inode->i_blocks = 0;
464 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
465 	switch(mode & S_IFMT) {
466 		case S_IFDIR:
467 			inode->i_fop = &simple_dir_operations;
468 			inode->i_op = &simple_dir_inode_operations;
469 			inode->i_nlink++;
470 		default:
471 			break;
472 	}
473 	return inode;
474 }
475 
476 /*
477  * FIXME: This probably has races.
478  */
479 static void
480 rpc_depopulate(struct dentry *parent)
481 {
482 	struct inode *dir = parent->d_inode;
483 	struct list_head *pos, *next;
484 	struct dentry *dentry, *dvec[10];
485 	int n = 0;
486 
487 	down(&dir->i_sem);
488 repeat:
489 	spin_lock(&dcache_lock);
490 	list_for_each_safe(pos, next, &parent->d_subdirs) {
491 		dentry = list_entry(pos, struct dentry, d_child);
492 		spin_lock(&dentry->d_lock);
493 		if (!d_unhashed(dentry)) {
494 			dget_locked(dentry);
495 			__d_drop(dentry);
496 			spin_unlock(&dentry->d_lock);
497 			dvec[n++] = dentry;
498 			if (n == ARRAY_SIZE(dvec))
499 				break;
500 		} else
501 			spin_unlock(&dentry->d_lock);
502 	}
503 	spin_unlock(&dcache_lock);
504 	if (n) {
505 		do {
506 			dentry = dvec[--n];
507 			if (dentry->d_inode) {
508 				rpc_close_pipes(dentry->d_inode);
509 				simple_unlink(dir, dentry);
510 			}
511 			dput(dentry);
512 		} while (n);
513 		goto repeat;
514 	}
515 	up(&dir->i_sem);
516 }
517 
518 static int
519 rpc_populate(struct dentry *parent,
520 		struct rpc_filelist *files,
521 		int start, int eof)
522 {
523 	struct inode *inode, *dir = parent->d_inode;
524 	void *private = RPC_I(dir)->private;
525 	struct dentry *dentry;
526 	int mode, i;
527 
528 	down(&dir->i_sem);
529 	for (i = start; i < eof; i++) {
530 		dentry = d_alloc_name(parent, files[i].name);
531 		if (!dentry)
532 			goto out_bad;
533 		mode = files[i].mode;
534 		inode = rpc_get_inode(dir->i_sb, mode);
535 		if (!inode) {
536 			dput(dentry);
537 			goto out_bad;
538 		}
539 		inode->i_ino = i;
540 		if (files[i].i_fop)
541 			inode->i_fop = files[i].i_fop;
542 		if (private)
543 			rpc_inode_setowner(inode, private);
544 		if (S_ISDIR(mode))
545 			dir->i_nlink++;
546 		d_add(dentry, inode);
547 	}
548 	up(&dir->i_sem);
549 	return 0;
550 out_bad:
551 	up(&dir->i_sem);
552 	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
553 			__FILE__, __FUNCTION__, parent->d_name.name);
554 	return -ENOMEM;
555 }
556 
557 static int
558 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
559 {
560 	struct inode *inode;
561 
562 	inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
563 	if (!inode)
564 		goto out_err;
565 	inode->i_ino = iunique(dir->i_sb, 100);
566 	d_instantiate(dentry, inode);
567 	dir->i_nlink++;
568 	inode_dir_notify(dir, DN_CREATE);
569 	rpc_get_mount();
570 	return 0;
571 out_err:
572 	printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
573 			__FILE__, __FUNCTION__, dentry->d_name.name);
574 	return -ENOMEM;
575 }
576 
577 static int
578 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
579 {
580 	int error;
581 
582 	shrink_dcache_parent(dentry);
583 	if (dentry->d_inode)
584 		rpc_close_pipes(dentry->d_inode);
585 	if ((error = simple_rmdir(dir, dentry)) != 0)
586 		return error;
587 	if (!error) {
588 		inode_dir_notify(dir, DN_DELETE);
589 		d_drop(dentry);
590 		rpc_put_mount();
591 	}
592 	return 0;
593 }
594 
595 static struct dentry *
596 rpc_lookup_negative(char *path, struct nameidata *nd)
597 {
598 	struct dentry *dentry;
599 	struct inode *dir;
600 	int error;
601 
602 	if ((error = rpc_lookup_parent(path, nd)) != 0)
603 		return ERR_PTR(error);
604 	dir = nd->dentry->d_inode;
605 	down(&dir->i_sem);
606 	dentry = lookup_hash(&nd->last, nd->dentry);
607 	if (IS_ERR(dentry))
608 		goto out_err;
609 	if (dentry->d_inode) {
610 		dput(dentry);
611 		dentry = ERR_PTR(-EEXIST);
612 		goto out_err;
613 	}
614 	return dentry;
615 out_err:
616 	up(&dir->i_sem);
617 	rpc_release_path(nd);
618 	return dentry;
619 }
620 
621 
622 struct dentry *
623 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
624 {
625 	struct nameidata nd;
626 	struct dentry *dentry;
627 	struct inode *dir;
628 	int error;
629 
630 	dentry = rpc_lookup_negative(path, &nd);
631 	if (IS_ERR(dentry))
632 		return dentry;
633 	dir = nd.dentry->d_inode;
634 	if ((error = __rpc_mkdir(dir, dentry)) != 0)
635 		goto err_dput;
636 	RPC_I(dentry->d_inode)->private = rpc_client;
637 	error = rpc_populate(dentry, authfiles,
638 			RPCAUTH_info, RPCAUTH_EOF);
639 	if (error)
640 		goto err_depopulate;
641 out:
642 	up(&dir->i_sem);
643 	rpc_release_path(&nd);
644 	return dentry;
645 err_depopulate:
646 	rpc_depopulate(dentry);
647 	__rpc_rmdir(dir, dentry);
648 err_dput:
649 	dput(dentry);
650 	printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
651 			__FILE__, __FUNCTION__, path, error);
652 	dentry = ERR_PTR(error);
653 	goto out;
654 }
655 
656 int
657 rpc_rmdir(char *path)
658 {
659 	struct nameidata nd;
660 	struct dentry *dentry;
661 	struct inode *dir;
662 	int error;
663 
664 	if ((error = rpc_lookup_parent(path, &nd)) != 0)
665 		return error;
666 	dir = nd.dentry->d_inode;
667 	down(&dir->i_sem);
668 	dentry = lookup_hash(&nd.last, nd.dentry);
669 	if (IS_ERR(dentry)) {
670 		error = PTR_ERR(dentry);
671 		goto out_release;
672 	}
673 	rpc_depopulate(dentry);
674 	error = __rpc_rmdir(dir, dentry);
675 	dput(dentry);
676 out_release:
677 	up(&dir->i_sem);
678 	rpc_release_path(&nd);
679 	return error;
680 }
681 
682 struct dentry *
683 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
684 {
685 	struct nameidata nd;
686 	struct dentry *dentry;
687 	struct inode *dir, *inode;
688 	struct rpc_inode *rpci;
689 
690 	dentry = rpc_lookup_negative(path, &nd);
691 	if (IS_ERR(dentry))
692 		return dentry;
693 	dir = nd.dentry->d_inode;
694 	inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
695 	if (!inode)
696 		goto err_dput;
697 	inode->i_ino = iunique(dir->i_sb, 100);
698 	inode->i_fop = &rpc_pipe_fops;
699 	d_instantiate(dentry, inode);
700 	rpci = RPC_I(inode);
701 	rpci->private = private;
702 	rpci->flags = flags;
703 	rpci->ops = ops;
704 	inode_dir_notify(dir, DN_CREATE);
705 out:
706 	up(&dir->i_sem);
707 	rpc_release_path(&nd);
708 	return dentry;
709 err_dput:
710 	dput(dentry);
711 	dentry = ERR_PTR(-ENOMEM);
712 	printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
713 			__FILE__, __FUNCTION__, path, -ENOMEM);
714 	goto out;
715 }
716 
717 int
718 rpc_unlink(char *path)
719 {
720 	struct nameidata nd;
721 	struct dentry *dentry;
722 	struct inode *dir;
723 	int error;
724 
725 	if ((error = rpc_lookup_parent(path, &nd)) != 0)
726 		return error;
727 	dir = nd.dentry->d_inode;
728 	down(&dir->i_sem);
729 	dentry = lookup_hash(&nd.last, nd.dentry);
730 	if (IS_ERR(dentry)) {
731 		error = PTR_ERR(dentry);
732 		goto out_release;
733 	}
734 	d_drop(dentry);
735 	if (dentry->d_inode) {
736 		rpc_close_pipes(dentry->d_inode);
737 		error = simple_unlink(dir, dentry);
738 	}
739 	dput(dentry);
740 	inode_dir_notify(dir, DN_DELETE);
741 out_release:
742 	up(&dir->i_sem);
743 	rpc_release_path(&nd);
744 	return error;
745 }
746 
747 /*
748  * populate the filesystem
749  */
750 static struct super_operations s_ops = {
751 	.alloc_inode	= rpc_alloc_inode,
752 	.destroy_inode	= rpc_destroy_inode,
753 	.statfs		= simple_statfs,
754 };
755 
756 #define RPCAUTH_GSSMAGIC 0x67596969
757 
758 static int
759 rpc_fill_super(struct super_block *sb, void *data, int silent)
760 {
761 	struct inode *inode;
762 	struct dentry *root;
763 
764 	sb->s_blocksize = PAGE_CACHE_SIZE;
765 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
766 	sb->s_magic = RPCAUTH_GSSMAGIC;
767 	sb->s_op = &s_ops;
768 	sb->s_time_gran = 1;
769 
770 	inode = rpc_get_inode(sb, S_IFDIR | 0755);
771 	if (!inode)
772 		return -ENOMEM;
773 	root = d_alloc_root(inode);
774 	if (!root) {
775 		iput(inode);
776 		return -ENOMEM;
777 	}
778 	if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
779 		goto out;
780 	sb->s_root = root;
781 	return 0;
782 out:
783 	d_genocide(root);
784 	dput(root);
785 	return -ENOMEM;
786 }
787 
788 static struct super_block *
789 rpc_get_sb(struct file_system_type *fs_type,
790 		int flags, const char *dev_name, void *data)
791 {
792 	return get_sb_single(fs_type, flags, data, rpc_fill_super);
793 }
794 
795 static struct file_system_type rpc_pipe_fs_type = {
796 	.owner		= THIS_MODULE,
797 	.name		= "rpc_pipefs",
798 	.get_sb		= rpc_get_sb,
799 	.kill_sb	= kill_litter_super,
800 };
801 
802 static void
803 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
804 {
805 	struct rpc_inode *rpci = (struct rpc_inode *) foo;
806 
807 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
808 	    SLAB_CTOR_CONSTRUCTOR) {
809 		inode_init_once(&rpci->vfs_inode);
810 		rpci->private = NULL;
811 		rpci->nreaders = 0;
812 		rpci->nwriters = 0;
813 		INIT_LIST_HEAD(&rpci->in_upcall);
814 		INIT_LIST_HEAD(&rpci->pipe);
815 		rpci->pipelen = 0;
816 		init_waitqueue_head(&rpci->waitq);
817 		INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
818 		rpci->ops = NULL;
819 	}
820 }
821 
822 int register_rpc_pipefs(void)
823 {
824 	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
825                                              sizeof(struct rpc_inode),
826                                              0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
827                                              init_once, NULL);
828 	if (!rpc_inode_cachep)
829 		return -ENOMEM;
830 	register_filesystem(&rpc_pipe_fs_type);
831 	return 0;
832 }
833 
834 void unregister_rpc_pipefs(void)
835 {
836 	if (kmem_cache_destroy(rpc_inode_cachep))
837 		printk(KERN_WARNING "RPC: unable to free inode cache\n");
838 	unregister_filesystem(&rpc_pipe_fs_type);
839 }
840