rpc_pipefs.c

  1/*
  2 *  Copyright (c) 2006,2007 The Regents of the University of Michigan.
  3 *  All rights reserved.
  4 *
  5 *  Andy Adamson <andros@citi.umich.edu>
  6 *  Fred Isaman <iisaman@umich.edu>
  7 *
  8 * permission is granted to use, copy, create derivative works and
  9 * redistribute this software and such derivative works for any purpose,
 10 * so long as the name of the university of michigan is not used in
 11 * any advertising or publicity pertaining to the use or distribution
 12 * of this software without specific, written prior authorization.  if
 13 * the above copyright notice or any other identification of the
 14 * university of michigan is included in any copy of any portion of
 15 * this software, then the disclaimer below must also be included.
 16 *
 17 * this software is provided as is, without representation from the
 18 * university of michigan as to its fitness for any purpose, and without
 19 * warranty by the university of michigan of any kind, either express
 20 * or implied, including without limitation the implied warranties of
 21 * merchantability and fitness for a particular purpose.  the regents
 22 * of the university of michigan shall not be liable for any damages,
 23 * including special, indirect, incidental, or consequential damages,
 24 * with respect to any claim arising out or in connection with the use
 25 * of the software, even if it has been or is hereafter advised of the
 26 * possibility of such damages.
 27 */
 28
 29#include <linux/module.h>
 30#include <linux/blkdev.h>
 31
 32#include "blocklayout.h"
 33
 34#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
 35
 36static void
 37nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
 38{
 39	int i;
 40
 41	*p++ = cpu_to_be32(1);
 42	*p++ = cpu_to_be32(b->type);
 43	*p++ = cpu_to_be32(b->simple.nr_sigs);
 44	for (i = 0; i < b->simple.nr_sigs; i++) {
 45		p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
 46		p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
 47					 b->simple.sigs[i].sig_len);
 48	}
 49}
 50
 51dev_t
 52bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
 53		gfp_t gfp_mask)
 54{
 55	struct net *net = server->nfs_client->cl_net;
 56	struct nfs_net *nn = net_generic(net, nfs_net_id);
 57	struct bl_dev_msg *reply = &nn->bl_mount_reply;
 58	struct bl_pipe_msg bl_pipe_msg;
 59	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
 60	struct bl_msg_hdr *bl_msg;
 61	DECLARE_WAITQUEUE(wq, current);
 62	dev_t dev = 0;
 63	int rc;
 64
 65	dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
 66
 67	mutex_lock(&nn->bl_mutex);
 68	bl_pipe_msg.bl_wq = &nn->bl_wq;
 69
 70	b->simple.len += 4;	/* single volume */
 71	if (b->simple.len > PAGE_SIZE)
 72		goto out_unlock;
 73
 74	memset(msg, 0, sizeof(*msg));
 75	msg->len = sizeof(*bl_msg) + b->simple.len;
 76	msg->data = kzalloc(msg->len, gfp_mask);
 77	if (!msg->data)
 78		goto out_unlock;
 79
 80	bl_msg = msg->data;
 81	bl_msg->type = BL_DEVICE_MOUNT;
 82	bl_msg->totallen = b->simple.len;
 83	nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
 84
 85	dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
 86	add_wait_queue(&nn->bl_wq, &wq);
 87	rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
 88	if (rc < 0) {
 89		remove_wait_queue(&nn->bl_wq, &wq);
 90		goto out_free_data;
 91	}
 92
 93	set_current_state(TASK_UNINTERRUPTIBLE);
 94	schedule();
 95	remove_wait_queue(&nn->bl_wq, &wq);
 96
 97	if (reply->status != BL_DEVICE_REQUEST_PROC) {
 98		printk(KERN_WARNING "%s failed to decode device: %d\n",
 99			__func__, reply->status);
100		goto out_free_data;
101	}
102
103	dev = MKDEV(reply->major, reply->minor);
104out_free_data:
105	kfree(msg->data);
106out_unlock:
107	mutex_unlock(&nn->bl_mutex);
108	return dev;
109}
110
111static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
112			 size_t mlen)
113{
114	struct nfs_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
115					 nfs_net_id);
116
117	if (mlen != sizeof (struct bl_dev_msg))
118		return -EINVAL;
119
120	if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
121		return -EFAULT;
122
123	wake_up(&nn->bl_wq);
124
125	return mlen;
126}
127
128static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
129{
130	struct bl_pipe_msg *bl_pipe_msg =
131		container_of(msg, struct bl_pipe_msg, msg);
132
133	if (msg->errno >= 0)
134		return;
135	wake_up(bl_pipe_msg->bl_wq);
136}
137
138static const struct rpc_pipe_ops bl_upcall_ops = {
139	.upcall		= rpc_pipe_generic_upcall,
140	.downcall	= bl_pipe_downcall,
141	.destroy_msg	= bl_pipe_destroy_msg,
142};
143
144static int nfs4blocklayout_register_sb(struct super_block *sb,
145					    struct rpc_pipe *pipe)
146{
147	struct dentry *dir;
148	int err;
149
150	dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
151	if (dir == NULL)
152		return -ENOENT;
153	err = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
154	dput(dir);
155	return err;
156}
157
158static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
159			   void *ptr)
160{
161	struct super_block *sb = ptr;
162	struct net *net = sb->s_fs_info;
163	struct nfs_net *nn = net_generic(net, nfs_net_id);
164	int ret = 0;
165
166	if (!try_module_get(THIS_MODULE))
167		return 0;
168
169	if (nn->bl_device_pipe == NULL) {
170		module_put(THIS_MODULE);
171		return 0;
172	}
173
174	switch (event) {
175	case RPC_PIPEFS_MOUNT:
176		ret = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
177		break;
178	case RPC_PIPEFS_UMOUNT:
179		rpc_unlink(nn->bl_device_pipe);
180		break;
181	default:
182		ret = -ENOTSUPP;
183		break;
184	}
185	module_put(THIS_MODULE);
186	return ret;
187}
188
189static struct notifier_block nfs4blocklayout_block = {
190	.notifier_call = rpc_pipefs_event,
191};
192
193static int nfs4blocklayout_register_net(struct net *net, struct rpc_pipe *pipe)
194{
195	struct super_block *pipefs_sb;
196	int ret;
197
198	pipefs_sb = rpc_get_sb_net(net);
199	if (!pipefs_sb)
200		return 0;
201	ret = nfs4blocklayout_register_sb(pipefs_sb, pipe);
202	rpc_put_sb_net(net);
203	return ret;
204}
205
206static void nfs4blocklayout_unregister_net(struct net *net,
207					   struct rpc_pipe *pipe)
208{
209	struct super_block *pipefs_sb;
210
211	pipefs_sb = rpc_get_sb_net(net);
212	if (pipefs_sb) {
213		rpc_unlink(pipe);
214		rpc_put_sb_net(net);
215	}
216}
217
218static int nfs4blocklayout_net_init(struct net *net)
219{
220	struct nfs_net *nn = net_generic(net, nfs_net_id);
221	int err;
222
223	mutex_init(&nn->bl_mutex);
224	init_waitqueue_head(&nn->bl_wq);
225	nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
226	if (IS_ERR(nn->bl_device_pipe))
227		return PTR_ERR(nn->bl_device_pipe);
228	err = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
229	if (unlikely(err))
230		rpc_destroy_pipe_data(nn->bl_device_pipe);
231	return err;
232}
233
234static void nfs4blocklayout_net_exit(struct net *net)
235{
236	struct nfs_net *nn = net_generic(net, nfs_net_id);
237
238	nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
239	rpc_destroy_pipe_data(nn->bl_device_pipe);
240	nn->bl_device_pipe = NULL;
241}
242
243static struct pernet_operations nfs4blocklayout_net_ops = {
244	.init = nfs4blocklayout_net_init,
245	.exit = nfs4blocklayout_net_exit,
246};
247
248int __init bl_init_pipefs(void)
249{
250	int ret;
251
252	ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
253	if (ret)
254		goto out;
255	ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
256	if (ret)
257		goto out_unregister_notifier;
258	return 0;
259
260out_unregister_notifier:
261	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
262out:
263	return ret;
264}
265
266void bl_cleanup_pipefs(void)
267{
268	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
269	unregister_pernet_subsys(&nfs4blocklayout_net_ops);
270}