rpc: add an rpc_pipe_open method
[linux-3.10.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
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 /**
80  * rpc_queue_upcall
81  * @inode: inode of upcall pipe on which to queue given message
82  * @msg: message to queue
83  *
84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
85  * A userspace process may then later read the upcall by performing a
86  * read on an open file for this inode.  It is up to the caller to
87  * initialize the fields of @msg (other than @msg->list) appropriately.
88  */
89 int
90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
91 {
92         struct rpc_inode *rpci = RPC_I(inode);
93         int res = -EPIPE;
94
95         spin_lock(&inode->i_lock);
96         if (rpci->ops == NULL)
97                 goto out;
98         if (rpci->nreaders) {
99                 list_add_tail(&msg->list, &rpci->pipe);
100                 rpci->pipelen += msg->len;
101                 res = 0;
102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
103                 if (list_empty(&rpci->pipe))
104                         queue_delayed_work(rpciod_workqueue,
105                                         &rpci->queue_timeout,
106                                         RPC_UPCALL_TIMEOUT);
107                 list_add_tail(&msg->list, &rpci->pipe);
108                 rpci->pipelen += msg->len;
109                 res = 0;
110         }
111 out:
112         spin_unlock(&inode->i_lock);
113         wake_up(&rpci->waitq);
114         return res;
115 }
116 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
117
118 static inline void
119 rpc_inode_setowner(struct inode *inode, void *private)
120 {
121         RPC_I(inode)->private = private;
122 }
123
124 static void
125 rpc_close_pipes(struct inode *inode)
126 {
127         struct rpc_inode *rpci = RPC_I(inode);
128         struct rpc_pipe_ops *ops;
129
130         mutex_lock(&inode->i_mutex);
131         ops = rpci->ops;
132         if (ops != NULL) {
133                 LIST_HEAD(free_list);
134
135                 spin_lock(&inode->i_lock);
136                 rpci->nreaders = 0;
137                 list_splice_init(&rpci->in_upcall, &free_list);
138                 list_splice_init(&rpci->pipe, &free_list);
139                 rpci->pipelen = 0;
140                 rpci->ops = NULL;
141                 spin_unlock(&inode->i_lock);
142                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
143                 rpci->nwriters = 0;
144                 if (ops->release_pipe)
145                         ops->release_pipe(inode);
146                 cancel_delayed_work_sync(&rpci->queue_timeout);
147         }
148         rpc_inode_setowner(inode, NULL);
149         mutex_unlock(&inode->i_mutex);
150 }
151
152 static struct inode *
153 rpc_alloc_inode(struct super_block *sb)
154 {
155         struct rpc_inode *rpci;
156         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
157         if (!rpci)
158                 return NULL;
159         return &rpci->vfs_inode;
160 }
161
162 static void
163 rpc_destroy_inode(struct inode *inode)
164 {
165         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
166 }
167
168 static int
169 rpc_pipe_open(struct inode *inode, struct file *filp)
170 {
171         struct rpc_inode *rpci = RPC_I(inode);
172         int first_open;
173         int res = -ENXIO;
174
175         mutex_lock(&inode->i_mutex);
176         if (rpci->ops == NULL)
177                 goto out;
178         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
179         if (first_open && rpci->ops->open_pipe) {
180                 res = rpci->ops->open_pipe(inode);
181                 if (res)
182                         goto out;
183         }
184         if (filp->f_mode & FMODE_READ)
185                 rpci->nreaders++;
186         if (filp->f_mode & FMODE_WRITE)
187                 rpci->nwriters++;
188         res = 0;
189 out:
190         mutex_unlock(&inode->i_mutex);
191         return res;
192 }
193
194 static int
195 rpc_pipe_release(struct inode *inode, struct file *filp)
196 {
197         struct rpc_inode *rpci = RPC_I(inode);
198         struct rpc_pipe_msg *msg;
199
200         mutex_lock(&inode->i_mutex);
201         if (rpci->ops == NULL)
202                 goto out;
203         msg = (struct rpc_pipe_msg *)filp->private_data;
204         if (msg != NULL) {
205                 spin_lock(&inode->i_lock);
206                 msg->errno = -EAGAIN;
207                 list_del(&msg->list);
208                 spin_unlock(&inode->i_lock);
209                 rpci->ops->destroy_msg(msg);
210         }
211         if (filp->f_mode & FMODE_WRITE)
212                 rpci->nwriters --;
213         if (filp->f_mode & FMODE_READ) {
214                 rpci->nreaders --;
215                 if (rpci->nreaders == 0) {
216                         LIST_HEAD(free_list);
217                         spin_lock(&inode->i_lock);
218                         list_splice_init(&rpci->pipe, &free_list);
219                         rpci->pipelen = 0;
220                         spin_unlock(&inode->i_lock);
221                         rpc_purge_list(rpci, &free_list,
222                                         rpci->ops->destroy_msg, -EAGAIN);
223                 }
224         }
225         if (rpci->ops->release_pipe)
226                 rpci->ops->release_pipe(inode);
227 out:
228         mutex_unlock(&inode->i_mutex);
229         return 0;
230 }
231
232 static ssize_t
233 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
234 {
235         struct inode *inode = filp->f_path.dentry->d_inode;
236         struct rpc_inode *rpci = RPC_I(inode);
237         struct rpc_pipe_msg *msg;
238         int res = 0;
239
240         mutex_lock(&inode->i_mutex);
241         if (rpci->ops == NULL) {
242                 res = -EPIPE;
243                 goto out_unlock;
244         }
245         msg = filp->private_data;
246         if (msg == NULL) {
247                 spin_lock(&inode->i_lock);
248                 if (!list_empty(&rpci->pipe)) {
249                         msg = list_entry(rpci->pipe.next,
250                                         struct rpc_pipe_msg,
251                                         list);
252                         list_move(&msg->list, &rpci->in_upcall);
253                         rpci->pipelen -= msg->len;
254                         filp->private_data = msg;
255                         msg->copied = 0;
256                 }
257                 spin_unlock(&inode->i_lock);
258                 if (msg == NULL)
259                         goto out_unlock;
260         }
261         /* NOTE: it is up to the callback to update msg->copied */
262         res = rpci->ops->upcall(filp, msg, buf, len);
263         if (res < 0 || msg->len == msg->copied) {
264                 filp->private_data = NULL;
265                 spin_lock(&inode->i_lock);
266                 list_del(&msg->list);
267                 spin_unlock(&inode->i_lock);
268                 rpci->ops->destroy_msg(msg);
269         }
270 out_unlock:
271         mutex_unlock(&inode->i_mutex);
272         return res;
273 }
274
275 static ssize_t
276 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
277 {
278         struct inode *inode = filp->f_path.dentry->d_inode;
279         struct rpc_inode *rpci = RPC_I(inode);
280         int res;
281
282         mutex_lock(&inode->i_mutex);
283         res = -EPIPE;
284         if (rpci->ops != NULL)
285                 res = rpci->ops->downcall(filp, buf, len);
286         mutex_unlock(&inode->i_mutex);
287         return res;
288 }
289
290 static unsigned int
291 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
292 {
293         struct rpc_inode *rpci;
294         unsigned int mask = 0;
295
296         rpci = RPC_I(filp->f_path.dentry->d_inode);
297         poll_wait(filp, &rpci->waitq, wait);
298
299         mask = POLLOUT | POLLWRNORM;
300         if (rpci->ops == NULL)
301                 mask |= POLLERR | POLLHUP;
302         if (filp->private_data || !list_empty(&rpci->pipe))
303                 mask |= POLLIN | POLLRDNORM;
304         return mask;
305 }
306
307 static int
308 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
309                 unsigned int cmd, unsigned long arg)
310 {
311         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
312         int len;
313
314         switch (cmd) {
315         case FIONREAD:
316                 if (rpci->ops == NULL)
317                         return -EPIPE;
318                 len = rpci->pipelen;
319                 if (filp->private_data) {
320                         struct rpc_pipe_msg *msg;
321                         msg = (struct rpc_pipe_msg *)filp->private_data;
322                         len += msg->len - msg->copied;
323                 }
324                 return put_user(len, (int __user *)arg);
325         default:
326                 return -EINVAL;
327         }
328 }
329
330 static const struct file_operations rpc_pipe_fops = {
331         .owner          = THIS_MODULE,
332         .llseek         = no_llseek,
333         .read           = rpc_pipe_read,
334         .write          = rpc_pipe_write,
335         .poll           = rpc_pipe_poll,
336         .ioctl          = rpc_pipe_ioctl,
337         .open           = rpc_pipe_open,
338         .release        = rpc_pipe_release,
339 };
340
341 static int
342 rpc_show_info(struct seq_file *m, void *v)
343 {
344         struct rpc_clnt *clnt = m->private;
345
346         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
347         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
348                         clnt->cl_prog, clnt->cl_vers);
349         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
350         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
351         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
352         return 0;
353 }
354
355 static int
356 rpc_info_open(struct inode *inode, struct file *file)
357 {
358         struct rpc_clnt *clnt;
359         int ret = single_open(file, rpc_show_info, NULL);
360
361         if (!ret) {
362                 struct seq_file *m = file->private_data;
363                 mutex_lock(&inode->i_mutex);
364                 clnt = RPC_I(inode)->private;
365                 if (clnt) {
366                         kref_get(&clnt->cl_kref);
367                         m->private = clnt;
368                 } else {
369                         single_release(inode, file);
370                         ret = -EINVAL;
371                 }
372                 mutex_unlock(&inode->i_mutex);
373         }
374         return ret;
375 }
376
377 static int
378 rpc_info_release(struct inode *inode, struct file *file)
379 {
380         struct seq_file *m = file->private_data;
381         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
382
383         if (clnt)
384                 rpc_release_client(clnt);
385         return single_release(inode, file);
386 }
387
388 static const struct file_operations rpc_info_operations = {
389         .owner          = THIS_MODULE,
390         .open           = rpc_info_open,
391         .read           = seq_read,
392         .llseek         = seq_lseek,
393         .release        = rpc_info_release,
394 };
395
396
397 /*
398  * We have a single directory with 1 node in it.
399  */
400 enum {
401         RPCAUTH_Root = 1,
402         RPCAUTH_lockd,
403         RPCAUTH_mount,
404         RPCAUTH_nfs,
405         RPCAUTH_portmap,
406         RPCAUTH_statd,
407         RPCAUTH_RootEOF
408 };
409
410 /*
411  * Description of fs contents.
412  */
413 struct rpc_filelist {
414         char *name;
415         const struct file_operations *i_fop;
416         int mode;
417 };
418
419 static struct rpc_filelist files[] = {
420         [RPCAUTH_lockd] = {
421                 .name = "lockd",
422                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
423         },
424         [RPCAUTH_mount] = {
425                 .name = "mount",
426                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
427         },
428         [RPCAUTH_nfs] = {
429                 .name = "nfs",
430                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
431         },
432         [RPCAUTH_portmap] = {
433                 .name = "portmap",
434                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
435         },
436         [RPCAUTH_statd] = {
437                 .name = "statd",
438                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
439         },
440 };
441
442 enum {
443         RPCAUTH_info = 2,
444         RPCAUTH_EOF
445 };
446
447 static struct rpc_filelist authfiles[] = {
448         [RPCAUTH_info] = {
449                 .name = "info",
450                 .i_fop = &rpc_info_operations,
451                 .mode = S_IFREG | S_IRUSR,
452         },
453 };
454
455 struct vfsmount *rpc_get_mount(void)
456 {
457         int err;
458
459         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
460         if (err != 0)
461                 return ERR_PTR(err);
462         return rpc_mount;
463 }
464
465 void rpc_put_mount(void)
466 {
467         simple_release_fs(&rpc_mount, &rpc_mount_count);
468 }
469
470 static int rpc_delete_dentry(struct dentry *dentry)
471 {
472         return 1;
473 }
474
475 static struct dentry_operations rpc_dentry_operations = {
476         .d_delete = rpc_delete_dentry,
477 };
478
479 static int
480 rpc_lookup_parent(char *path, struct nameidata *nd)
481 {
482         struct vfsmount *mnt;
483
484         if (path[0] == '\0')
485                 return -ENOENT;
486
487         mnt = rpc_get_mount();
488         if (IS_ERR(mnt)) {
489                 printk(KERN_WARNING "%s: %s failed to mount "
490                                "pseudofilesystem \n", __FILE__, __func__);
491                 return PTR_ERR(mnt);
492         }
493
494         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
495                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
496                                 __FILE__, __func__, path);
497                 rpc_put_mount();
498                 return -ENOENT;
499         }
500         return 0;
501 }
502
503 static void
504 rpc_release_path(struct nameidata *nd)
505 {
506         path_put(&nd->path);
507         rpc_put_mount();
508 }
509
510 static struct inode *
511 rpc_get_inode(struct super_block *sb, int mode)
512 {
513         struct inode *inode = new_inode(sb);
514         if (!inode)
515                 return NULL;
516         inode->i_mode = mode;
517         inode->i_uid = inode->i_gid = 0;
518         inode->i_blocks = 0;
519         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
520         switch(mode & S_IFMT) {
521                 case S_IFDIR:
522                         inode->i_fop = &simple_dir_operations;
523                         inode->i_op = &simple_dir_inode_operations;
524                         inc_nlink(inode);
525                 default:
526                         break;
527         }
528         return inode;
529 }
530
531 /*
532  * FIXME: This probably has races.
533  */
534 static void rpc_depopulate(struct dentry *parent,
535                            unsigned long start, unsigned long eof)
536 {
537         struct inode *dir = parent->d_inode;
538         struct list_head *pos, *next;
539         struct dentry *dentry, *dvec[10];
540         int n = 0;
541
542         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
543 repeat:
544         spin_lock(&dcache_lock);
545         list_for_each_safe(pos, next, &parent->d_subdirs) {
546                 dentry = list_entry(pos, struct dentry, d_u.d_child);
547                 if (!dentry->d_inode ||
548                                 dentry->d_inode->i_ino < start ||
549                                 dentry->d_inode->i_ino >= eof)
550                         continue;
551                 spin_lock(&dentry->d_lock);
552                 if (!d_unhashed(dentry)) {
553                         dget_locked(dentry);
554                         __d_drop(dentry);
555                         spin_unlock(&dentry->d_lock);
556                         dvec[n++] = dentry;
557                         if (n == ARRAY_SIZE(dvec))
558                                 break;
559                 } else
560                         spin_unlock(&dentry->d_lock);
561         }
562         spin_unlock(&dcache_lock);
563         if (n) {
564                 do {
565                         dentry = dvec[--n];
566                         if (S_ISREG(dentry->d_inode->i_mode))
567                                 simple_unlink(dir, dentry);
568                         else if (S_ISDIR(dentry->d_inode->i_mode))
569                                 simple_rmdir(dir, dentry);
570                         d_delete(dentry);
571                         dput(dentry);
572                 } while (n);
573                 goto repeat;
574         }
575         mutex_unlock(&dir->i_mutex);
576 }
577
578 static int
579 rpc_populate(struct dentry *parent,
580                 struct rpc_filelist *files,
581                 int start, int eof)
582 {
583         struct inode *inode, *dir = parent->d_inode;
584         void *private = RPC_I(dir)->private;
585         struct dentry *dentry;
586         int mode, i;
587
588         mutex_lock(&dir->i_mutex);
589         for (i = start; i < eof; i++) {
590                 dentry = d_alloc_name(parent, files[i].name);
591                 if (!dentry)
592                         goto out_bad;
593                 dentry->d_op = &rpc_dentry_operations;
594                 mode = files[i].mode;
595                 inode = rpc_get_inode(dir->i_sb, mode);
596                 if (!inode) {
597                         dput(dentry);
598                         goto out_bad;
599                 }
600                 inode->i_ino = i;
601                 if (files[i].i_fop)
602                         inode->i_fop = files[i].i_fop;
603                 if (private)
604                         rpc_inode_setowner(inode, private);
605                 if (S_ISDIR(mode))
606                         inc_nlink(dir);
607                 d_add(dentry, inode);
608                 fsnotify_create(dir, dentry);
609         }
610         mutex_unlock(&dir->i_mutex);
611         return 0;
612 out_bad:
613         mutex_unlock(&dir->i_mutex);
614         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
615                         __FILE__, __func__, parent->d_name.name);
616         return -ENOMEM;
617 }
618
619 static int
620 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
621 {
622         struct inode *inode;
623
624         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
625         if (!inode)
626                 goto out_err;
627         inode->i_ino = iunique(dir->i_sb, 100);
628         d_instantiate(dentry, inode);
629         inc_nlink(dir);
630         fsnotify_mkdir(dir, dentry);
631         return 0;
632 out_err:
633         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
634                         __FILE__, __func__, dentry->d_name.name);
635         return -ENOMEM;
636 }
637
638 static int
639 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
640 {
641         int error;
642         error = simple_rmdir(dir, dentry);
643         if (!error)
644                 d_delete(dentry);
645         return error;
646 }
647
648 static struct dentry *
649 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
650 {
651         struct inode *dir = parent->d_inode;
652         struct dentry *dentry;
653
654         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
655         dentry = lookup_one_len(name, parent, len);
656         if (IS_ERR(dentry))
657                 goto out_err;
658         if (!dentry->d_inode)
659                 dentry->d_op = &rpc_dentry_operations;
660         else if (exclusive) {
661                 dput(dentry);
662                 dentry = ERR_PTR(-EEXIST);
663                 goto out_err;
664         }
665         return dentry;
666 out_err:
667         mutex_unlock(&dir->i_mutex);
668         return dentry;
669 }
670
671 static struct dentry *
672 rpc_lookup_negative(char *path, struct nameidata *nd)
673 {
674         struct dentry *dentry;
675         int error;
676
677         if ((error = rpc_lookup_parent(path, nd)) != 0)
678                 return ERR_PTR(error);
679         dentry = rpc_lookup_create(nd->path.dentry, nd->last.name, nd->last.len,
680                                    1);
681         if (IS_ERR(dentry))
682                 rpc_release_path(nd);
683         return dentry;
684 }
685
686 /**
687  * rpc_mkdir - Create a new directory in rpc_pipefs
688  * @path: path from the rpc_pipefs root to the new directory
689  * @rpc_client: rpc client to associate with this directory
690  *
691  * This creates a directory at the given @path associated with
692  * @rpc_clnt, which will contain a file named "info" with some basic
693  * information about the client, together with any "pipes" that may
694  * later be created using rpc_mkpipe().
695  */
696 struct dentry *
697 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
698 {
699         struct nameidata nd;
700         struct dentry *dentry;
701         struct inode *dir;
702         int error;
703
704         dentry = rpc_lookup_negative(path, &nd);
705         if (IS_ERR(dentry))
706                 return dentry;
707         dir = nd.path.dentry->d_inode;
708         if ((error = __rpc_mkdir(dir, dentry)) != 0)
709                 goto err_dput;
710         RPC_I(dentry->d_inode)->private = rpc_client;
711         error = rpc_populate(dentry, authfiles,
712                         RPCAUTH_info, RPCAUTH_EOF);
713         if (error)
714                 goto err_depopulate;
715         dget(dentry);
716 out:
717         mutex_unlock(&dir->i_mutex);
718         rpc_release_path(&nd);
719         return dentry;
720 err_depopulate:
721         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
722         __rpc_rmdir(dir, dentry);
723 err_dput:
724         dput(dentry);
725         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
726                         __FILE__, __func__, path, error);
727         dentry = ERR_PTR(error);
728         goto out;
729 }
730
731 /**
732  * rpc_rmdir - Remove a directory created with rpc_mkdir()
733  * @dentry: directory to remove
734  */
735 int
736 rpc_rmdir(struct dentry *dentry)
737 {
738         struct dentry *parent;
739         struct inode *dir;
740         int error;
741
742         parent = dget_parent(dentry);
743         dir = parent->d_inode;
744         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
745         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
746         error = __rpc_rmdir(dir, dentry);
747         dput(dentry);
748         mutex_unlock(&dir->i_mutex);
749         dput(parent);
750         return error;
751 }
752
753 /**
754  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
755  * @parent: dentry of directory to create new "pipe" in
756  * @name: name of pipe
757  * @private: private data to associate with the pipe, for the caller's use
758  * @ops: operations defining the behavior of the pipe: upcall, downcall,
759  *      release_pipe, open_pipe, and destroy_msg.
760  * @flags: rpc_inode flags
761  *
762  * Data is made available for userspace to read by calls to
763  * rpc_queue_upcall().  The actual reads will result in calls to
764  * @ops->upcall, which will be called with the file pointer,
765  * message, and userspace buffer to copy to.
766  *
767  * Writes can come at any time, and do not necessarily have to be
768  * responses to upcalls.  They will result in calls to @msg->downcall.
769  *
770  * The @private argument passed here will be available to all these methods
771  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
772  */
773 struct dentry *
774 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
775 {
776         struct dentry *dentry;
777         struct inode *dir, *inode;
778         struct rpc_inode *rpci;
779
780         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
781         if (IS_ERR(dentry))
782                 return dentry;
783         dir = parent->d_inode;
784         if (dentry->d_inode) {
785                 rpci = RPC_I(dentry->d_inode);
786                 if (rpci->private != private ||
787                                 rpci->ops != ops ||
788                                 rpci->flags != flags) {
789                         dput (dentry);
790                         dentry = ERR_PTR(-EBUSY);
791                 }
792                 rpci->nkern_readwriters++;
793                 goto out;
794         }
795         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
796         if (!inode)
797                 goto err_dput;
798         inode->i_ino = iunique(dir->i_sb, 100);
799         inode->i_fop = &rpc_pipe_fops;
800         d_instantiate(dentry, inode);
801         rpci = RPC_I(inode);
802         rpci->private = private;
803         rpci->flags = flags;
804         rpci->ops = ops;
805         rpci->nkern_readwriters = 1;
806         fsnotify_create(dir, dentry);
807         dget(dentry);
808 out:
809         mutex_unlock(&dir->i_mutex);
810         return dentry;
811 err_dput:
812         dput(dentry);
813         dentry = ERR_PTR(-ENOMEM);
814         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
815                         __FILE__, __func__, parent->d_name.name, name,
816                         -ENOMEM);
817         goto out;
818 }
819 EXPORT_SYMBOL_GPL(rpc_mkpipe);
820
821 /**
822  * rpc_unlink - remove a pipe
823  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
824  *
825  * After this call, lookups will no longer find the pipe, and any
826  * attempts to read or write using preexisting opens of the pipe will
827  * return -EPIPE.
828  */
829 int
830 rpc_unlink(struct dentry *dentry)
831 {
832         struct dentry *parent;
833         struct inode *dir;
834         int error = 0;
835
836         parent = dget_parent(dentry);
837         dir = parent->d_inode;
838         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
839         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
840                 rpc_close_pipes(dentry->d_inode);
841                 error = simple_unlink(dir, dentry);
842                 if (!error)
843                         d_delete(dentry);
844         }
845         dput(dentry);
846         mutex_unlock(&dir->i_mutex);
847         dput(parent);
848         return error;
849 }
850 EXPORT_SYMBOL_GPL(rpc_unlink);
851
852 /*
853  * populate the filesystem
854  */
855 static struct super_operations s_ops = {
856         .alloc_inode    = rpc_alloc_inode,
857         .destroy_inode  = rpc_destroy_inode,
858         .statfs         = simple_statfs,
859 };
860
861 #define RPCAUTH_GSSMAGIC 0x67596969
862
863 static int
864 rpc_fill_super(struct super_block *sb, void *data, int silent)
865 {
866         struct inode *inode;
867         struct dentry *root;
868
869         sb->s_blocksize = PAGE_CACHE_SIZE;
870         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
871         sb->s_magic = RPCAUTH_GSSMAGIC;
872         sb->s_op = &s_ops;
873         sb->s_time_gran = 1;
874
875         inode = rpc_get_inode(sb, S_IFDIR | 0755);
876         if (!inode)
877                 return -ENOMEM;
878         root = d_alloc_root(inode);
879         if (!root) {
880                 iput(inode);
881                 return -ENOMEM;
882         }
883         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
884                 goto out;
885         sb->s_root = root;
886         return 0;
887 out:
888         d_genocide(root);
889         dput(root);
890         return -ENOMEM;
891 }
892
893 static int
894 rpc_get_sb(struct file_system_type *fs_type,
895                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
896 {
897         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
898 }
899
900 static struct file_system_type rpc_pipe_fs_type = {
901         .owner          = THIS_MODULE,
902         .name           = "rpc_pipefs",
903         .get_sb         = rpc_get_sb,
904         .kill_sb        = kill_litter_super,
905 };
906
907 static void
908 init_once(void *foo)
909 {
910         struct rpc_inode *rpci = (struct rpc_inode *) foo;
911
912         inode_init_once(&rpci->vfs_inode);
913         rpci->private = NULL;
914         rpci->nreaders = 0;
915         rpci->nwriters = 0;
916         INIT_LIST_HEAD(&rpci->in_upcall);
917         INIT_LIST_HEAD(&rpci->in_downcall);
918         INIT_LIST_HEAD(&rpci->pipe);
919         rpci->pipelen = 0;
920         init_waitqueue_head(&rpci->waitq);
921         INIT_DELAYED_WORK(&rpci->queue_timeout,
922                             rpc_timeout_upcall_queue);
923         rpci->ops = NULL;
924 }
925
926 int register_rpc_pipefs(void)
927 {
928         int err;
929
930         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
931                                 sizeof(struct rpc_inode),
932                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
933                                                 SLAB_MEM_SPREAD),
934                                 init_once);
935         if (!rpc_inode_cachep)
936                 return -ENOMEM;
937         err = register_filesystem(&rpc_pipe_fs_type);
938         if (err) {
939                 kmem_cache_destroy(rpc_inode_cachep);
940                 return err;
941         }
942
943         return 0;
944 }
945
946 void unregister_rpc_pipefs(void)
947 {
948         kmem_cache_destroy(rpc_inode_cachep);
949         unregister_filesystem(&rpc_pipe_fs_type);
950 }