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Linux/net/sunrpc/rpc_pipe.c

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

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