Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/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 #include <linux/rcupdate.h>
 20 #include <linux/utsname.h>
 21 
 22 #include <asm/ioctls.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 #include <linux/sunrpc/cache.h>
 31 #include <linux/nsproxy.h>
 32 #include <linux/notifier.h>
 33 
 34 #include "netns.h"
 35 #include "sunrpc.h"
 36 
 37 #define RPCDBG_FACILITY RPCDBG_DEBUG
 38 
 39 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
 40 
 41 static struct file_system_type rpc_pipe_fs_type;
 42 static const struct rpc_pipe_ops gssd_dummy_pipe_ops;
 43 
 44 static struct kmem_cache *rpc_inode_cachep __read_mostly;
 45 
 46 #define RPC_UPCALL_TIMEOUT (30*HZ)
 47 
 48 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
 49 
 50 int rpc_pipefs_notifier_register(struct notifier_block *nb)
 51 {
 52         return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
 53 }
 54 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
 55 
 56 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
 57 {
 58         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
 59 }
 60 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
 61 
 62 static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
 63                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
 64 {
 65         struct rpc_pipe_msg *msg;
 66 
 67         if (list_empty(head))
 68                 return;
 69         do {
 70                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
 71                 list_del_init(&msg->list);
 72                 msg->errno = err;
 73                 destroy_msg(msg);
 74         } while (!list_empty(head));
 75 
 76         if (waitq)
 77                 wake_up(waitq);
 78 }
 79 
 80 static void
 81 rpc_timeout_upcall_queue(struct work_struct *work)
 82 {
 83         LIST_HEAD(free_list);
 84         struct rpc_pipe *pipe =
 85                 container_of(work, struct rpc_pipe, queue_timeout.work);
 86         void (*destroy_msg)(struct rpc_pipe_msg *);
 87         struct dentry *dentry;
 88 
 89         spin_lock(&pipe->lock);
 90         destroy_msg = pipe->ops->destroy_msg;
 91         if (pipe->nreaders == 0) {
 92                 list_splice_init(&pipe->pipe, &free_list);
 93                 pipe->pipelen = 0;
 94         }
 95         dentry = dget(pipe->dentry);
 96         spin_unlock(&pipe->lock);
 97         rpc_purge_list(dentry ? &RPC_I(dentry->d_inode)->waitq : NULL,
 98                         &free_list, destroy_msg, -ETIMEDOUT);
 99         dput(dentry);
100 }
101 
102 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
103                                 char __user *dst, size_t buflen)
104 {
105         char *data = (char *)msg->data + msg->copied;
106         size_t mlen = min(msg->len - msg->copied, buflen);
107         unsigned long left;
108 
109         left = copy_to_user(dst, data, mlen);
110         if (left == mlen) {
111                 msg->errno = -EFAULT;
112                 return -EFAULT;
113         }
114 
115         mlen -= left;
116         msg->copied += mlen;
117         msg->errno = 0;
118         return mlen;
119 }
120 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
121 
122 /**
123  * rpc_queue_upcall - queue an upcall message to userspace
124  * @pipe: upcall pipe on which to queue given message
125  * @msg: message to queue
126  *
127  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
128  * A userspace process may then later read the upcall by performing a
129  * read on an open file for this inode.  It is up to the caller to
130  * initialize the fields of @msg (other than @msg->list) appropriately.
131  */
132 int
133 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
134 {
135         int res = -EPIPE;
136         struct dentry *dentry;
137 
138         spin_lock(&pipe->lock);
139         if (pipe->nreaders) {
140                 list_add_tail(&msg->list, &pipe->pipe);
141                 pipe->pipelen += msg->len;
142                 res = 0;
143         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
144                 if (list_empty(&pipe->pipe))
145                         queue_delayed_work(rpciod_workqueue,
146                                         &pipe->queue_timeout,
147                                         RPC_UPCALL_TIMEOUT);
148                 list_add_tail(&msg->list, &pipe->pipe);
149                 pipe->pipelen += msg->len;
150                 res = 0;
151         }
152         dentry = dget(pipe->dentry);
153         spin_unlock(&pipe->lock);
154         if (dentry) {
155                 wake_up(&RPC_I(dentry->d_inode)->waitq);
156                 dput(dentry);
157         }
158         return res;
159 }
160 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
161 
162 static inline void
163 rpc_inode_setowner(struct inode *inode, void *private)
164 {
165         RPC_I(inode)->private = private;
166 }
167 
168 static void
169 rpc_close_pipes(struct inode *inode)
170 {
171         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
172         int need_release;
173         LIST_HEAD(free_list);
174 
175         mutex_lock(&inode->i_mutex);
176         spin_lock(&pipe->lock);
177         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
178         pipe->nreaders = 0;
179         list_splice_init(&pipe->in_upcall, &free_list);
180         list_splice_init(&pipe->pipe, &free_list);
181         pipe->pipelen = 0;
182         pipe->dentry = NULL;
183         spin_unlock(&pipe->lock);
184         rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
185         pipe->nwriters = 0;
186         if (need_release && pipe->ops->release_pipe)
187                 pipe->ops->release_pipe(inode);
188         cancel_delayed_work_sync(&pipe->queue_timeout);
189         rpc_inode_setowner(inode, NULL);
190         RPC_I(inode)->pipe = NULL;
191         mutex_unlock(&inode->i_mutex);
192 }
193 
194 static struct inode *
195 rpc_alloc_inode(struct super_block *sb)
196 {
197         struct rpc_inode *rpci;
198         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
199         if (!rpci)
200                 return NULL;
201         return &rpci->vfs_inode;
202 }
203 
204 static void
205 rpc_i_callback(struct rcu_head *head)
206 {
207         struct inode *inode = container_of(head, struct inode, i_rcu);
208         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
209 }
210 
211 static void
212 rpc_destroy_inode(struct inode *inode)
213 {
214         call_rcu(&inode->i_rcu, rpc_i_callback);
215 }
216 
217 static int
218 rpc_pipe_open(struct inode *inode, struct file *filp)
219 {
220         struct rpc_pipe *pipe;
221         int first_open;
222         int res = -ENXIO;
223 
224         mutex_lock(&inode->i_mutex);
225         pipe = RPC_I(inode)->pipe;
226         if (pipe == NULL)
227                 goto out;
228         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
229         if (first_open && pipe->ops->open_pipe) {
230                 res = pipe->ops->open_pipe(inode);
231                 if (res)
232                         goto out;
233         }
234         if (filp->f_mode & FMODE_READ)
235                 pipe->nreaders++;
236         if (filp->f_mode & FMODE_WRITE)
237                 pipe->nwriters++;
238         res = 0;
239 out:
240         mutex_unlock(&inode->i_mutex);
241         return res;
242 }
243 
244 static int
245 rpc_pipe_release(struct inode *inode, struct file *filp)
246 {
247         struct rpc_pipe *pipe;
248         struct rpc_pipe_msg *msg;
249         int last_close;
250 
251         mutex_lock(&inode->i_mutex);
252         pipe = RPC_I(inode)->pipe;
253         if (pipe == NULL)
254                 goto out;
255         msg = filp->private_data;
256         if (msg != NULL) {
257                 spin_lock(&pipe->lock);
258                 msg->errno = -EAGAIN;
259                 list_del_init(&msg->list);
260                 spin_unlock(&pipe->lock);
261                 pipe->ops->destroy_msg(msg);
262         }
263         if (filp->f_mode & FMODE_WRITE)
264                 pipe->nwriters --;
265         if (filp->f_mode & FMODE_READ) {
266                 pipe->nreaders --;
267                 if (pipe->nreaders == 0) {
268                         LIST_HEAD(free_list);
269                         spin_lock(&pipe->lock);
270                         list_splice_init(&pipe->pipe, &free_list);
271                         pipe->pipelen = 0;
272                         spin_unlock(&pipe->lock);
273                         rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
274                                         pipe->ops->destroy_msg, -EAGAIN);
275                 }
276         }
277         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
278         if (last_close && pipe->ops->release_pipe)
279                 pipe->ops->release_pipe(inode);
280 out:
281         mutex_unlock(&inode->i_mutex);
282         return 0;
283 }
284 
285 static ssize_t
286 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
287 {
288         struct inode *inode = file_inode(filp);
289         struct rpc_pipe *pipe;
290         struct rpc_pipe_msg *msg;
291         int res = 0;
292 
293         mutex_lock(&inode->i_mutex);
294         pipe = RPC_I(inode)->pipe;
295         if (pipe == NULL) {
296                 res = -EPIPE;
297                 goto out_unlock;
298         }
299         msg = filp->private_data;
300         if (msg == NULL) {
301                 spin_lock(&pipe->lock);
302                 if (!list_empty(&pipe->pipe)) {
303                         msg = list_entry(pipe->pipe.next,
304                                         struct rpc_pipe_msg,
305                                         list);
306                         list_move(&msg->list, &pipe->in_upcall);
307                         pipe->pipelen -= msg->len;
308                         filp->private_data = msg;
309                         msg->copied = 0;
310                 }
311                 spin_unlock(&pipe->lock);
312                 if (msg == NULL)
313                         goto out_unlock;
314         }
315         /* NOTE: it is up to the callback to update msg->copied */
316         res = pipe->ops->upcall(filp, msg, buf, len);
317         if (res < 0 || msg->len == msg->copied) {
318                 filp->private_data = NULL;
319                 spin_lock(&pipe->lock);
320                 list_del_init(&msg->list);
321                 spin_unlock(&pipe->lock);
322                 pipe->ops->destroy_msg(msg);
323         }
324 out_unlock:
325         mutex_unlock(&inode->i_mutex);
326         return res;
327 }
328 
329 static ssize_t
330 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
331 {
332         struct inode *inode = file_inode(filp);
333         int res;
334 
335         mutex_lock(&inode->i_mutex);
336         res = -EPIPE;
337         if (RPC_I(inode)->pipe != NULL)
338                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
339         mutex_unlock(&inode->i_mutex);
340         return res;
341 }
342 
343 static unsigned int
344 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
345 {
346         struct inode *inode = file_inode(filp);
347         struct rpc_inode *rpci = RPC_I(inode);
348         unsigned int mask = POLLOUT | POLLWRNORM;
349 
350         poll_wait(filp, &rpci->waitq, wait);
351 
352         mutex_lock(&inode->i_mutex);
353         if (rpci->pipe == NULL)
354                 mask |= POLLERR | POLLHUP;
355         else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
356                 mask |= POLLIN | POLLRDNORM;
357         mutex_unlock(&inode->i_mutex);
358         return mask;
359 }
360 
361 static long
362 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
363 {
364         struct inode *inode = file_inode(filp);
365         struct rpc_pipe *pipe;
366         int len;
367 
368         switch (cmd) {
369         case FIONREAD:
370                 mutex_lock(&inode->i_mutex);
371                 pipe = RPC_I(inode)->pipe;
372                 if (pipe == NULL) {
373                         mutex_unlock(&inode->i_mutex);
374                         return -EPIPE;
375                 }
376                 spin_lock(&pipe->lock);
377                 len = pipe->pipelen;
378                 if (filp->private_data) {
379                         struct rpc_pipe_msg *msg;
380                         msg = filp->private_data;
381                         len += msg->len - msg->copied;
382                 }
383                 spin_unlock(&pipe->lock);
384                 mutex_unlock(&inode->i_mutex);
385                 return put_user(len, (int __user *)arg);
386         default:
387                 return -EINVAL;
388         }
389 }
390 
391 static const struct file_operations rpc_pipe_fops = {
392         .owner          = THIS_MODULE,
393         .llseek         = no_llseek,
394         .read           = rpc_pipe_read,
395         .write          = rpc_pipe_write,
396         .poll           = rpc_pipe_poll,
397         .unlocked_ioctl = rpc_pipe_ioctl,
398         .open           = rpc_pipe_open,
399         .release        = rpc_pipe_release,
400 };
401 
402 static int
403 rpc_show_info(struct seq_file *m, void *v)
404 {
405         struct rpc_clnt *clnt = m->private;
406 
407         rcu_read_lock();
408         seq_printf(m, "RPC server: %s\n",
409                         rcu_dereference(clnt->cl_xprt)->servername);
410         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_program->name,
411                         clnt->cl_prog, clnt->cl_vers);
412         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
413         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
414         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
415         rcu_read_unlock();
416         return 0;
417 }
418 
419 static int
420 rpc_info_open(struct inode *inode, struct file *file)
421 {
422         struct rpc_clnt *clnt = NULL;
423         int ret = single_open(file, rpc_show_info, NULL);
424 
425         if (!ret) {
426                 struct seq_file *m = file->private_data;
427 
428                 spin_lock(&file->f_path.dentry->d_lock);
429                 if (!d_unhashed(file->f_path.dentry))
430                         clnt = RPC_I(inode)->private;
431                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
432                         spin_unlock(&file->f_path.dentry->d_lock);
433                         m->private = clnt;
434                 } else {
435                         spin_unlock(&file->f_path.dentry->d_lock);
436                         single_release(inode, file);
437                         ret = -EINVAL;
438                 }
439         }
440         return ret;
441 }
442 
443 static int
444 rpc_info_release(struct inode *inode, struct file *file)
445 {
446         struct seq_file *m = file->private_data;
447         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
448 
449         if (clnt)
450                 rpc_release_client(clnt);
451         return single_release(inode, file);
452 }
453 
454 static const struct file_operations rpc_info_operations = {
455         .owner          = THIS_MODULE,
456         .open           = rpc_info_open,
457         .read           = seq_read,
458         .llseek         = seq_lseek,
459         .release        = rpc_info_release,
460 };
461 
462 
463 /*
464  * Description of fs contents.
465  */
466 struct rpc_filelist {
467         const char *name;
468         const struct file_operations *i_fop;
469         umode_t mode;
470 };
471 
472 static struct inode *
473 rpc_get_inode(struct super_block *sb, umode_t mode)
474 {
475         struct inode *inode = new_inode(sb);
476         if (!inode)
477                 return NULL;
478         inode->i_ino = get_next_ino();
479         inode->i_mode = mode;
480         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
481         switch (mode & S_IFMT) {
482         case S_IFDIR:
483                 inode->i_fop = &simple_dir_operations;
484                 inode->i_op = &simple_dir_inode_operations;
485                 inc_nlink(inode);
486         default:
487                 break;
488         }
489         return inode;
490 }
491 
492 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
493                                umode_t mode,
494                                const struct file_operations *i_fop,
495                                void *private)
496 {
497         struct inode *inode;
498 
499         d_drop(dentry);
500         inode = rpc_get_inode(dir->i_sb, mode);
501         if (!inode)
502                 goto out_err;
503         inode->i_ino = iunique(dir->i_sb, 100);
504         if (i_fop)
505                 inode->i_fop = i_fop;
506         if (private)
507                 rpc_inode_setowner(inode, private);
508         d_add(dentry, inode);
509         return 0;
510 out_err:
511         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
512                         __FILE__, __func__, dentry);
513         dput(dentry);
514         return -ENOMEM;
515 }
516 
517 static int __rpc_create(struct inode *dir, struct dentry *dentry,
518                         umode_t mode,
519                         const struct file_operations *i_fop,
520                         void *private)
521 {
522         int err;
523 
524         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
525         if (err)
526                 return err;
527         fsnotify_create(dir, dentry);
528         return 0;
529 }
530 
531 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
532                        umode_t mode,
533                        const struct file_operations *i_fop,
534                        void *private)
535 {
536         int err;
537 
538         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
539         if (err)
540                 return err;
541         inc_nlink(dir);
542         fsnotify_mkdir(dir, dentry);
543         return 0;
544 }
545 
546 static void
547 init_pipe(struct rpc_pipe *pipe)
548 {
549         pipe->nreaders = 0;
550         pipe->nwriters = 0;
551         INIT_LIST_HEAD(&pipe->in_upcall);
552         INIT_LIST_HEAD(&pipe->in_downcall);
553         INIT_LIST_HEAD(&pipe->pipe);
554         pipe->pipelen = 0;
555         INIT_DELAYED_WORK(&pipe->queue_timeout,
556                             rpc_timeout_upcall_queue);
557         pipe->ops = NULL;
558         spin_lock_init(&pipe->lock);
559         pipe->dentry = NULL;
560 }
561 
562 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
563 {
564         kfree(pipe);
565 }
566 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
567 
568 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
569 {
570         struct rpc_pipe *pipe;
571 
572         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
573         if (!pipe)
574                 return ERR_PTR(-ENOMEM);
575         init_pipe(pipe);
576         pipe->ops = ops;
577         pipe->flags = flags;
578         return pipe;
579 }
580 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
581 
582 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
583                                umode_t mode,
584                                const struct file_operations *i_fop,
585                                void *private,
586                                struct rpc_pipe *pipe)
587 {
588         struct rpc_inode *rpci;
589         int err;
590 
591         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
592         if (err)
593                 return err;
594         rpci = RPC_I(dentry->d_inode);
595         rpci->private = private;
596         rpci->pipe = pipe;
597         fsnotify_create(dir, dentry);
598         return 0;
599 }
600 
601 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
602 {
603         int ret;
604 
605         dget(dentry);
606         ret = simple_rmdir(dir, dentry);
607         d_delete(dentry);
608         dput(dentry);
609         return ret;
610 }
611 
612 int rpc_rmdir(struct dentry *dentry)
613 {
614         struct dentry *parent;
615         struct inode *dir;
616         int error;
617 
618         parent = dget_parent(dentry);
619         dir = parent->d_inode;
620         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
621         error = __rpc_rmdir(dir, dentry);
622         mutex_unlock(&dir->i_mutex);
623         dput(parent);
624         return error;
625 }
626 EXPORT_SYMBOL_GPL(rpc_rmdir);
627 
628 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
629 {
630         int ret;
631 
632         dget(dentry);
633         ret = simple_unlink(dir, dentry);
634         d_delete(dentry);
635         dput(dentry);
636         return ret;
637 }
638 
639 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
640 {
641         struct inode *inode = dentry->d_inode;
642 
643         rpc_close_pipes(inode);
644         return __rpc_unlink(dir, dentry);
645 }
646 
647 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
648                                           const char *name)
649 {
650         struct qstr q = QSTR_INIT(name, strlen(name));
651         struct dentry *dentry = d_hash_and_lookup(parent, &q);
652         if (!dentry) {
653                 dentry = d_alloc(parent, &q);
654                 if (!dentry)
655                         return ERR_PTR(-ENOMEM);
656         }
657         if (dentry->d_inode == NULL)
658                 return dentry;
659         dput(dentry);
660         return ERR_PTR(-EEXIST);
661 }
662 
663 /*
664  * FIXME: This probably has races.
665  */
666 static void __rpc_depopulate(struct dentry *parent,
667                              const struct rpc_filelist *files,
668                              int start, int eof)
669 {
670         struct inode *dir = parent->d_inode;
671         struct dentry *dentry;
672         struct qstr name;
673         int i;
674 
675         for (i = start; i < eof; i++) {
676                 name.name = files[i].name;
677                 name.len = strlen(files[i].name);
678                 dentry = d_hash_and_lookup(parent, &name);
679 
680                 if (dentry == NULL)
681                         continue;
682                 if (dentry->d_inode == NULL)
683                         goto next;
684                 switch (dentry->d_inode->i_mode & S_IFMT) {
685                         default:
686                                 BUG();
687                         case S_IFREG:
688                                 __rpc_unlink(dir, dentry);
689                                 break;
690                         case S_IFDIR:
691                                 __rpc_rmdir(dir, dentry);
692                 }
693 next:
694                 dput(dentry);
695         }
696 }
697 
698 static void rpc_depopulate(struct dentry *parent,
699                            const struct rpc_filelist *files,
700                            int start, int eof)
701 {
702         struct inode *dir = parent->d_inode;
703 
704         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
705         __rpc_depopulate(parent, files, start, eof);
706         mutex_unlock(&dir->i_mutex);
707 }
708 
709 static int rpc_populate(struct dentry *parent,
710                         const struct rpc_filelist *files,
711                         int start, int eof,
712                         void *private)
713 {
714         struct inode *dir = parent->d_inode;
715         struct dentry *dentry;
716         int i, err;
717 
718         mutex_lock(&dir->i_mutex);
719         for (i = start; i < eof; i++) {
720                 dentry = __rpc_lookup_create_exclusive(parent, files[i].name);
721                 err = PTR_ERR(dentry);
722                 if (IS_ERR(dentry))
723                         goto out_bad;
724                 switch (files[i].mode & S_IFMT) {
725                         default:
726                                 BUG();
727                         case S_IFREG:
728                                 err = __rpc_create(dir, dentry,
729                                                 files[i].mode,
730                                                 files[i].i_fop,
731                                                 private);
732                                 break;
733                         case S_IFDIR:
734                                 err = __rpc_mkdir(dir, dentry,
735                                                 files[i].mode,
736                                                 NULL,
737                                                 private);
738                 }
739                 if (err != 0)
740                         goto out_bad;
741         }
742         mutex_unlock(&dir->i_mutex);
743         return 0;
744 out_bad:
745         __rpc_depopulate(parent, files, start, eof);
746         mutex_unlock(&dir->i_mutex);
747         printk(KERN_WARNING "%s: %s failed to populate directory %pd\n",
748                         __FILE__, __func__, parent);
749         return err;
750 }
751 
752 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
753                 const char *name, umode_t mode, void *private,
754                 int (*populate)(struct dentry *, void *), void *args_populate)
755 {
756         struct dentry *dentry;
757         struct inode *dir = parent->d_inode;
758         int error;
759 
760         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
761         dentry = __rpc_lookup_create_exclusive(parent, name);
762         if (IS_ERR(dentry))
763                 goto out;
764         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
765         if (error != 0)
766                 goto out_err;
767         if (populate != NULL) {
768                 error = populate(dentry, args_populate);
769                 if (error)
770                         goto err_rmdir;
771         }
772 out:
773         mutex_unlock(&dir->i_mutex);
774         return dentry;
775 err_rmdir:
776         __rpc_rmdir(dir, dentry);
777 out_err:
778         dentry = ERR_PTR(error);
779         goto out;
780 }
781 
782 static int rpc_rmdir_depopulate(struct dentry *dentry,
783                 void (*depopulate)(struct dentry *))
784 {
785         struct dentry *parent;
786         struct inode *dir;
787         int error;
788 
789         parent = dget_parent(dentry);
790         dir = parent->d_inode;
791         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
792         if (depopulate != NULL)
793                 depopulate(dentry);
794         error = __rpc_rmdir(dir, dentry);
795         mutex_unlock(&dir->i_mutex);
796         dput(parent);
797         return error;
798 }
799 
800 /**
801  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
802  * @parent: dentry of directory to create new "pipe" in
803  * @name: name of pipe
804  * @private: private data to associate with the pipe, for the caller's use
805  * @pipe: &rpc_pipe containing input parameters
806  *
807  * Data is made available for userspace to read by calls to
808  * rpc_queue_upcall().  The actual reads will result in calls to
809  * @ops->upcall, which will be called with the file pointer,
810  * message, and userspace buffer to copy to.
811  *
812  * Writes can come at any time, and do not necessarily have to be
813  * responses to upcalls.  They will result in calls to @msg->downcall.
814  *
815  * The @private argument passed here will be available to all these methods
816  * from the file pointer, via RPC_I(file_inode(file))->private.
817  */
818 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
819                                  void *private, struct rpc_pipe *pipe)
820 {
821         struct dentry *dentry;
822         struct inode *dir = parent->d_inode;
823         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
824         int err;
825 
826         if (pipe->ops->upcall == NULL)
827                 umode &= ~S_IRUGO;
828         if (pipe->ops->downcall == NULL)
829                 umode &= ~S_IWUGO;
830 
831         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
832         dentry = __rpc_lookup_create_exclusive(parent, name);
833         if (IS_ERR(dentry))
834                 goto out;
835         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
836                                   private, pipe);
837         if (err)
838                 goto out_err;
839 out:
840         mutex_unlock(&dir->i_mutex);
841         return dentry;
842 out_err:
843         dentry = ERR_PTR(err);
844         printk(KERN_WARNING "%s: %s() failed to create pipe %pd/%s (errno = %d)\n",
845                         __FILE__, __func__, parent, name,
846                         err);
847         goto out;
848 }
849 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
850 
851 /**
852  * rpc_unlink - remove a pipe
853  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
854  *
855  * After this call, lookups will no longer find the pipe, and any
856  * attempts to read or write using preexisting opens of the pipe will
857  * return -EPIPE.
858  */
859 int
860 rpc_unlink(struct dentry *dentry)
861 {
862         struct dentry *parent;
863         struct inode *dir;
864         int error = 0;
865 
866         parent = dget_parent(dentry);
867         dir = parent->d_inode;
868         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
869         error = __rpc_rmpipe(dir, dentry);
870         mutex_unlock(&dir->i_mutex);
871         dput(parent);
872         return error;
873 }
874 EXPORT_SYMBOL_GPL(rpc_unlink);
875 
876 /**
877  * rpc_init_pipe_dir_head - initialise a struct rpc_pipe_dir_head
878  * @pdh: pointer to struct rpc_pipe_dir_head
879  */
880 void rpc_init_pipe_dir_head(struct rpc_pipe_dir_head *pdh)
881 {
882         INIT_LIST_HEAD(&pdh->pdh_entries);
883         pdh->pdh_dentry = NULL;
884 }
885 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_head);
886 
887 /**
888  * rpc_init_pipe_dir_object - initialise a struct rpc_pipe_dir_object
889  * @pdo: pointer to struct rpc_pipe_dir_object
890  * @pdo_ops: pointer to const struct rpc_pipe_dir_object_ops
891  * @pdo_data: pointer to caller-defined data
892  */
893 void rpc_init_pipe_dir_object(struct rpc_pipe_dir_object *pdo,
894                 const struct rpc_pipe_dir_object_ops *pdo_ops,
895                 void *pdo_data)
896 {
897         INIT_LIST_HEAD(&pdo->pdo_head);
898         pdo->pdo_ops = pdo_ops;
899         pdo->pdo_data = pdo_data;
900 }
901 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_object);
902 
903 static int
904 rpc_add_pipe_dir_object_locked(struct net *net,
905                 struct rpc_pipe_dir_head *pdh,
906                 struct rpc_pipe_dir_object *pdo)
907 {
908         int ret = 0;
909 
910         if (pdh->pdh_dentry)
911                 ret = pdo->pdo_ops->create(pdh->pdh_dentry, pdo);
912         if (ret == 0)
913                 list_add_tail(&pdo->pdo_head, &pdh->pdh_entries);
914         return ret;
915 }
916 
917 static void
918 rpc_remove_pipe_dir_object_locked(struct net *net,
919                 struct rpc_pipe_dir_head *pdh,
920                 struct rpc_pipe_dir_object *pdo)
921 {
922         if (pdh->pdh_dentry)
923                 pdo->pdo_ops->destroy(pdh->pdh_dentry, pdo);
924         list_del_init(&pdo->pdo_head);
925 }
926 
927 /**
928  * rpc_add_pipe_dir_object - associate a rpc_pipe_dir_object to a directory
929  * @net: pointer to struct net
930  * @pdh: pointer to struct rpc_pipe_dir_head
931  * @pdo: pointer to struct rpc_pipe_dir_object
932  *
933  */
934 int
935 rpc_add_pipe_dir_object(struct net *net,
936                 struct rpc_pipe_dir_head *pdh,
937                 struct rpc_pipe_dir_object *pdo)
938 {
939         int ret = 0;
940 
941         if (list_empty(&pdo->pdo_head)) {
942                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
943 
944                 mutex_lock(&sn->pipefs_sb_lock);
945                 ret = rpc_add_pipe_dir_object_locked(net, pdh, pdo);
946                 mutex_unlock(&sn->pipefs_sb_lock);
947         }
948         return ret;
949 }
950 EXPORT_SYMBOL_GPL(rpc_add_pipe_dir_object);
951 
952 /**
953  * rpc_remove_pipe_dir_object - remove a rpc_pipe_dir_object from a directory
954  * @net: pointer to struct net
955  * @pdh: pointer to struct rpc_pipe_dir_head
956  * @pdo: pointer to struct rpc_pipe_dir_object
957  *
958  */
959 void
960 rpc_remove_pipe_dir_object(struct net *net,
961                 struct rpc_pipe_dir_head *pdh,
962                 struct rpc_pipe_dir_object *pdo)
963 {
964         if (!list_empty(&pdo->pdo_head)) {
965                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
966 
967                 mutex_lock(&sn->pipefs_sb_lock);
968                 rpc_remove_pipe_dir_object_locked(net, pdh, pdo);
969                 mutex_unlock(&sn->pipefs_sb_lock);
970         }
971 }
972 EXPORT_SYMBOL_GPL(rpc_remove_pipe_dir_object);
973 
974 /**
975  * rpc_find_or_alloc_pipe_dir_object
976  * @net: pointer to struct net
977  * @pdh: pointer to struct rpc_pipe_dir_head
978  * @match: match struct rpc_pipe_dir_object to data
979  * @alloc: allocate a new struct rpc_pipe_dir_object
980  * @data: user defined data for match() and alloc()
981  *
982  */
983 struct rpc_pipe_dir_object *
984 rpc_find_or_alloc_pipe_dir_object(struct net *net,
985                 struct rpc_pipe_dir_head *pdh,
986                 int (*match)(struct rpc_pipe_dir_object *, void *),
987                 struct rpc_pipe_dir_object *(*alloc)(void *),
988                 void *data)
989 {
990         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
991         struct rpc_pipe_dir_object *pdo;
992 
993         mutex_lock(&sn->pipefs_sb_lock);
994         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head) {
995                 if (!match(pdo, data))
996                         continue;
997                 goto out;
998         }
999         pdo = alloc(data);
1000         if (!pdo)
1001                 goto out;
1002         rpc_add_pipe_dir_object_locked(net, pdh, pdo);
1003 out:
1004         mutex_unlock(&sn->pipefs_sb_lock);
1005         return pdo;
1006 }
1007 EXPORT_SYMBOL_GPL(rpc_find_or_alloc_pipe_dir_object);
1008 
1009 static void
1010 rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1011 {
1012         struct rpc_pipe_dir_object *pdo;
1013         struct dentry *dir = pdh->pdh_dentry;
1014 
1015         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1016                 pdo->pdo_ops->create(dir, pdo);
1017 }
1018 
1019 static void
1020 rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1021 {
1022         struct rpc_pipe_dir_object *pdo;
1023         struct dentry *dir = pdh->pdh_dentry;
1024 
1025         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1026                 pdo->pdo_ops->destroy(dir, pdo);
1027 }
1028 
1029 enum {
1030         RPCAUTH_info,
1031         RPCAUTH_EOF
1032 };
1033 
1034 static const struct rpc_filelist authfiles[] = {
1035         [RPCAUTH_info] = {
1036                 .name = "info",
1037                 .i_fop = &rpc_info_operations,
1038                 .mode = S_IFREG | S_IRUSR,
1039         },
1040 };
1041 
1042 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
1043 {
1044         return rpc_populate(dentry,
1045                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
1046                             private);
1047 }
1048 
1049 static void rpc_clntdir_depopulate(struct dentry *dentry)
1050 {
1051         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
1052 }
1053 
1054 /**
1055  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
1056  * @dentry: the parent of new directory
1057  * @name: the name of new directory
1058  * @rpc_client: rpc client to associate with this directory
1059  *
1060  * This creates a directory at the given @path associated with
1061  * @rpc_clnt, which will contain a file named "info" with some basic
1062  * information about the client, together with any "pipes" that may
1063  * later be created using rpc_mkpipe().
1064  */
1065 struct dentry *rpc_create_client_dir(struct dentry *dentry,
1066                                    const char *name,
1067                                    struct rpc_clnt *rpc_client)
1068 {
1069         struct dentry *ret;
1070 
1071         ret = rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
1072                         rpc_clntdir_populate, rpc_client);
1073         if (!IS_ERR(ret)) {
1074                 rpc_client->cl_pipedir_objects.pdh_dentry = ret;
1075                 rpc_create_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1076         }
1077         return ret;
1078 }
1079 
1080 /**
1081  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
1082  * @rpc_client: rpc_client for the pipe
1083  */
1084 int rpc_remove_client_dir(struct rpc_clnt *rpc_client)
1085 {
1086         struct dentry *dentry = rpc_client->cl_pipedir_objects.pdh_dentry;
1087 
1088         if (dentry == NULL)
1089                 return 0;
1090         rpc_destroy_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1091         rpc_client->cl_pipedir_objects.pdh_dentry = NULL;
1092         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
1093 }
1094 
1095 static const struct rpc_filelist cache_pipefs_files[3] = {
1096         [0] = {
1097                 .name = "channel",
1098                 .i_fop = &cache_file_operations_pipefs,
1099                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
1100         },
1101         [1] = {
1102                 .name = "content",
1103                 .i_fop = &content_file_operations_pipefs,
1104                 .mode = S_IFREG|S_IRUSR,
1105         },
1106         [2] = {
1107                 .name = "flush",
1108                 .i_fop = &cache_flush_operations_pipefs,
1109                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
1110         },
1111 };
1112 
1113 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
1114 {
1115         return rpc_populate(dentry,
1116                             cache_pipefs_files, 0, 3,
1117                             private);
1118 }
1119 
1120 static void rpc_cachedir_depopulate(struct dentry *dentry)
1121 {
1122         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
1123 }
1124 
1125 struct dentry *rpc_create_cache_dir(struct dentry *parent, const char *name,
1126                                     umode_t umode, struct cache_detail *cd)
1127 {
1128         return rpc_mkdir_populate(parent, name, umode, NULL,
1129                         rpc_cachedir_populate, cd);
1130 }
1131 
1132 void rpc_remove_cache_dir(struct dentry *dentry)
1133 {
1134         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
1135 }
1136 
1137 /*
1138  * populate the filesystem
1139  */
1140 static const struct super_operations s_ops = {
1141         .alloc_inode    = rpc_alloc_inode,
1142         .destroy_inode  = rpc_destroy_inode,
1143         .statfs         = simple_statfs,
1144 };
1145 
1146 #define RPCAUTH_GSSMAGIC 0x67596969
1147 
1148 /*
1149  * We have a single directory with 1 node in it.
1150  */
1151 enum {
1152         RPCAUTH_lockd,
1153         RPCAUTH_mount,
1154         RPCAUTH_nfs,
1155         RPCAUTH_portmap,
1156         RPCAUTH_statd,
1157         RPCAUTH_nfsd4_cb,
1158         RPCAUTH_cache,
1159         RPCAUTH_nfsd,
1160         RPCAUTH_gssd,
1161         RPCAUTH_RootEOF
1162 };
1163 
1164 static const struct rpc_filelist files[] = {
1165         [RPCAUTH_lockd] = {
1166                 .name = "lockd",
1167                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1168         },
1169         [RPCAUTH_mount] = {
1170                 .name = "mount",
1171                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1172         },
1173         [RPCAUTH_nfs] = {
1174                 .name = "nfs",
1175                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1176         },
1177         [RPCAUTH_portmap] = {
1178                 .name = "portmap",
1179                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1180         },
1181         [RPCAUTH_statd] = {
1182                 .name = "statd",
1183                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1184         },
1185         [RPCAUTH_nfsd4_cb] = {
1186                 .name = "nfsd4_cb",
1187                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1188         },
1189         [RPCAUTH_cache] = {
1190                 .name = "cache",
1191                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1192         },
1193         [RPCAUTH_nfsd] = {
1194                 .name = "nfsd",
1195                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1196         },
1197         [RPCAUTH_gssd] = {
1198                 .name = "gssd",
1199                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1200         },
1201 };
1202 
1203 /*
1204  * This call can be used only in RPC pipefs mount notification hooks.
1205  */
1206 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1207                                const unsigned char *dir_name)
1208 {
1209         struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1210         return d_hash_and_lookup(sb->s_root, &dir);
1211 }
1212 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1213 
1214 int rpc_pipefs_init_net(struct net *net)
1215 {
1216         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1217 
1218         sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);
1219         if (IS_ERR(sn->gssd_dummy))
1220                 return PTR_ERR(sn->gssd_dummy);
1221 
1222         mutex_init(&sn->pipefs_sb_lock);
1223         sn->pipe_version = -1;
1224         return 0;
1225 }
1226 
1227 void rpc_pipefs_exit_net(struct net *net)
1228 {
1229         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1230 
1231         rpc_destroy_pipe_data(sn->gssd_dummy);
1232 }
1233 
1234 /*
1235  * This call will be used for per network namespace operations calls.
1236  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1237  * found. This lock have to be released by rpc_put_sb_net() when all operations
1238  * will be completed.
1239  */
1240 struct super_block *rpc_get_sb_net(const struct net *net)
1241 {
1242         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1243 
1244         mutex_lock(&sn->pipefs_sb_lock);
1245         if (sn->pipefs_sb)
1246                 return sn->pipefs_sb;
1247         mutex_unlock(&sn->pipefs_sb_lock);
1248         return NULL;
1249 }
1250 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1251 
1252 void rpc_put_sb_net(const struct net *net)
1253 {
1254         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1255 
1256         WARN_ON(sn->pipefs_sb == NULL);
1257         mutex_unlock(&sn->pipefs_sb_lock);
1258 }
1259 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1260 
1261 static const struct rpc_filelist gssd_dummy_clnt_dir[] = {
1262         [0] = {
1263                 .name = "clntXX",
1264                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1265         },
1266 };
1267 
1268 static ssize_t
1269 dummy_downcall(struct file *filp, const char __user *src, size_t len)
1270 {
1271         return -EINVAL;
1272 }
1273 
1274 static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {
1275         .upcall         = rpc_pipe_generic_upcall,
1276         .downcall       = dummy_downcall,
1277 };
1278 
1279 /*
1280  * Here we present a bogus "info" file to keep rpc.gssd happy. We don't expect
1281  * that it will ever use this info to handle an upcall, but rpc.gssd expects
1282  * that this file will be there and have a certain format.
1283  */
1284 static int
1285 rpc_show_dummy_info(struct seq_file *m, void *v)
1286 {
1287         seq_printf(m, "RPC server: %s\n", utsname()->nodename);
1288         seq_printf(m, "service: foo (1) version 0\n");
1289         seq_printf(m, "address: 127.0.0.1\n");
1290         seq_printf(m, "protocol: tcp\n");
1291         seq_printf(m, "port: 0\n");
1292         return 0;
1293 }
1294 
1295 static int
1296 rpc_dummy_info_open(struct inode *inode, struct file *file)
1297 {
1298         return single_open(file, rpc_show_dummy_info, NULL);
1299 }
1300 
1301 static const struct file_operations rpc_dummy_info_operations = {
1302         .owner          = THIS_MODULE,
1303         .open           = rpc_dummy_info_open,
1304         .read           = seq_read,
1305         .llseek         = seq_lseek,
1306         .release        = single_release,
1307 };
1308 
1309 static const struct rpc_filelist gssd_dummy_info_file[] = {
1310         [0] = {
1311                 .name = "info",
1312                 .i_fop = &rpc_dummy_info_operations,
1313                 .mode = S_IFREG | S_IRUSR,
1314         },
1315 };
1316 
1317 /**
1318  * rpc_gssd_dummy_populate - create a dummy gssd pipe
1319  * @root:       root of the rpc_pipefs filesystem
1320  * @pipe_data:  pipe data created when netns is initialized
1321  *
1322  * Create a dummy set of directories and a pipe that gssd can hold open to
1323  * indicate that it is up and running.
1324  */
1325 static struct dentry *
1326 rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
1327 {
1328         int ret = 0;
1329         struct dentry *gssd_dentry;
1330         struct dentry *clnt_dentry = NULL;
1331         struct dentry *pipe_dentry = NULL;
1332         struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,
1333                                   strlen(files[RPCAUTH_gssd].name));
1334 
1335         /* We should never get this far if "gssd" doesn't exist */
1336         gssd_dentry = d_hash_and_lookup(root, &q);
1337         if (!gssd_dentry)
1338                 return ERR_PTR(-ENOENT);
1339 
1340         ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
1341         if (ret) {
1342                 pipe_dentry = ERR_PTR(ret);
1343                 goto out;
1344         }
1345 
1346         q.name = gssd_dummy_clnt_dir[0].name;
1347         q.len = strlen(gssd_dummy_clnt_dir[0].name);
1348         clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
1349         if (!clnt_dentry) {
1350                 pipe_dentry = ERR_PTR(-ENOENT);
1351                 goto out;
1352         }
1353 
1354         ret = rpc_populate(clnt_dentry, gssd_dummy_info_file, 0, 1, NULL);
1355         if (ret) {
1356                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1357                 pipe_dentry = ERR_PTR(ret);
1358                 goto out;
1359         }
1360 
1361         pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);
1362         if (IS_ERR(pipe_dentry)) {
1363                 __rpc_depopulate(clnt_dentry, gssd_dummy_info_file, 0, 1);
1364                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1365         }
1366 out:
1367         dput(clnt_dentry);
1368         dput(gssd_dentry);
1369         return pipe_dentry;
1370 }
1371 
1372 static void
1373 rpc_gssd_dummy_depopulate(struct dentry *pipe_dentry)
1374 {
1375         struct dentry *clnt_dir = pipe_dentry->d_parent;
1376         struct dentry *gssd_dir = clnt_dir->d_parent;
1377 
1378         __rpc_rmpipe(clnt_dir->d_inode, pipe_dentry);
1379         __rpc_depopulate(clnt_dir, gssd_dummy_info_file, 0, 1);
1380         __rpc_depopulate(gssd_dir, gssd_dummy_clnt_dir, 0, 1);
1381         dput(pipe_dentry);
1382 }
1383 
1384 static int
1385 rpc_fill_super(struct super_block *sb, void *data, int silent)
1386 {
1387         struct inode *inode;
1388         struct dentry *root, *gssd_dentry;
1389         struct net *net = data;
1390         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1391         int err;
1392 
1393         sb->s_blocksize = PAGE_CACHE_SIZE;
1394         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1395         sb->s_magic = RPCAUTH_GSSMAGIC;
1396         sb->s_op = &s_ops;
1397         sb->s_d_op = &simple_dentry_operations;
1398         sb->s_time_gran = 1;
1399 
1400         inode = rpc_get_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO);
1401         sb->s_root = root = d_make_root(inode);
1402         if (!root)
1403                 return -ENOMEM;
1404         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1405                 return -ENOMEM;
1406 
1407         gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);
1408         if (IS_ERR(gssd_dentry)) {
1409                 __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1410                 return PTR_ERR(gssd_dentry);
1411         }
1412 
1413         dprintk("RPC:       sending pipefs MOUNT notification for net %p%s\n",
1414                 net, NET_NAME(net));
1415         mutex_lock(&sn->pipefs_sb_lock);
1416         sn->pipefs_sb = sb;
1417         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1418                                            RPC_PIPEFS_MOUNT,
1419                                            sb);
1420         if (err)
1421                 goto err_depopulate;
1422         sb->s_fs_info = get_net(net);
1423         mutex_unlock(&sn->pipefs_sb_lock);
1424         return 0;
1425 
1426 err_depopulate:
1427         rpc_gssd_dummy_depopulate(gssd_dentry);
1428         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1429                                            RPC_PIPEFS_UMOUNT,
1430                                            sb);
1431         sn->pipefs_sb = NULL;
1432         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1433         mutex_unlock(&sn->pipefs_sb_lock);
1434         return err;
1435 }
1436 
1437 bool
1438 gssd_running(struct net *net)
1439 {
1440         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1441         struct rpc_pipe *pipe = sn->gssd_dummy;
1442 
1443         return pipe->nreaders || pipe->nwriters;
1444 }
1445 EXPORT_SYMBOL_GPL(gssd_running);
1446 
1447 static struct dentry *
1448 rpc_mount(struct file_system_type *fs_type,
1449                 int flags, const char *dev_name, void *data)
1450 {
1451         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
1452 }
1453 
1454 static void rpc_kill_sb(struct super_block *sb)
1455 {
1456         struct net *net = sb->s_fs_info;
1457         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1458 
1459         mutex_lock(&sn->pipefs_sb_lock);
1460         if (sn->pipefs_sb != sb) {
1461                 mutex_unlock(&sn->pipefs_sb_lock);
1462                 goto out;
1463         }
1464         sn->pipefs_sb = NULL;
1465         dprintk("RPC:       sending pipefs UMOUNT notification for net %p%s\n",
1466                 net, NET_NAME(net));
1467         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1468                                            RPC_PIPEFS_UMOUNT,
1469                                            sb);
1470         mutex_unlock(&sn->pipefs_sb_lock);
1471         put_net(net);
1472 out:
1473         kill_litter_super(sb);
1474 }
1475 
1476 static struct file_system_type rpc_pipe_fs_type = {
1477         .owner          = THIS_MODULE,
1478         .name           = "rpc_pipefs",
1479         .mount          = rpc_mount,
1480         .kill_sb        = rpc_kill_sb,
1481 };
1482 MODULE_ALIAS_FS("rpc_pipefs");
1483 MODULE_ALIAS("rpc_pipefs");
1484 
1485 static void
1486 init_once(void *foo)
1487 {
1488         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1489 
1490         inode_init_once(&rpci->vfs_inode);
1491         rpci->private = NULL;
1492         rpci->pipe = NULL;
1493         init_waitqueue_head(&rpci->waitq);
1494 }
1495 
1496 int register_rpc_pipefs(void)
1497 {
1498         int err;
1499 
1500         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1501                                 sizeof(struct rpc_inode),
1502                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1503                                                 SLAB_MEM_SPREAD),
1504                                 init_once);
1505         if (!rpc_inode_cachep)
1506                 return -ENOMEM;
1507         err = rpc_clients_notifier_register();
1508         if (err)
1509                 goto err_notifier;
1510         err = register_filesystem(&rpc_pipe_fs_type);
1511         if (err)
1512                 goto err_register;
1513         return 0;
1514 
1515 err_register:
1516         rpc_clients_notifier_unregister();
1517 err_notifier:
1518         kmem_cache_destroy(rpc_inode_cachep);
1519         return err;
1520 }
1521 
1522 void unregister_rpc_pipefs(void)
1523 {
1524         rpc_clients_notifier_unregister();
1525         kmem_cache_destroy(rpc_inode_cachep);
1526         unregister_filesystem(&rpc_pipe_fs_type);
1527 }
1528 

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