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 struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
145					    struct rpc_pipe *pipe)
146{
147	struct dentry *dir, *dentry;
148
149	dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
150	if (dir == NULL)
151		return ERR_PTR(-ENOENT);
152	dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
153	dput(dir);
154	return dentry;
155}
156
157static void nfs4blocklayout_unregister_sb(struct super_block *sb,
158					  struct rpc_pipe *pipe)
159{
160	if (pipe->dentry)
161		rpc_unlink(pipe->dentry);
162}
163
164static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
165			   void *ptr)
166{
167	struct super_block *sb = ptr;
168	struct net *net = sb->s_fs_info;
169	struct nfs_net *nn = net_generic(net, nfs_net_id);
170	struct dentry *dentry;
171	int ret = 0;
172
173	if (!try_module_get(THIS_MODULE))
174		return 0;
175
176	if (nn->bl_device_pipe == NULL) {
177		module_put(THIS_MODULE);
178		return 0;
179	}
180
181	switch (event) {
182	case RPC_PIPEFS_MOUNT:
183		dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
184		if (IS_ERR(dentry)) {
185			ret = PTR_ERR(dentry);
186			break;
187		}
188		nn->bl_device_pipe->dentry = dentry;
189		break;
190	case RPC_PIPEFS_UMOUNT:
191		if (nn->bl_device_pipe->dentry)
192			nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
193		break;
194	default:
195		ret = -ENOTSUPP;
196		break;
197	}
198	module_put(THIS_MODULE);
199	return ret;
200}
201
202static struct notifier_block nfs4blocklayout_block = {
203	.notifier_call = rpc_pipefs_event,
204};
205
206static struct dentry *nfs4blocklayout_register_net(struct net *net,
207						   struct rpc_pipe *pipe)
208{
209	struct super_block *pipefs_sb;
210	struct dentry *dentry;
211
212	pipefs_sb = rpc_get_sb_net(net);
213	if (!pipefs_sb)
214		return NULL;
215	dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
216	rpc_put_sb_net(net);
217	return dentry;
218}
219
220static void nfs4blocklayout_unregister_net(struct net *net,
221					   struct rpc_pipe *pipe)
222{
223	struct super_block *pipefs_sb;
224
225	pipefs_sb = rpc_get_sb_net(net);
226	if (pipefs_sb) {
227		nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
228		rpc_put_sb_net(net);
229	}
230}
231
232static int nfs4blocklayout_net_init(struct net *net)
233{
234	struct nfs_net *nn = net_generic(net, nfs_net_id);
235	struct dentry *dentry;
236
237	mutex_init(&nn->bl_mutex);
238	init_waitqueue_head(&nn->bl_wq);
239	nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
240	if (IS_ERR(nn->bl_device_pipe))
241		return PTR_ERR(nn->bl_device_pipe);
242	dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
243	if (IS_ERR(dentry)) {
244		rpc_destroy_pipe_data(nn->bl_device_pipe);
245		return PTR_ERR(dentry);
246	}
247	nn->bl_device_pipe->dentry = dentry;
248	return 0;
249}
250
251static void nfs4blocklayout_net_exit(struct net *net)
252{
253	struct nfs_net *nn = net_generic(net, nfs_net_id);
254
255	nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
256	rpc_destroy_pipe_data(nn->bl_device_pipe);
257	nn->bl_device_pipe = NULL;
258}
259
260static struct pernet_operations nfs4blocklayout_net_ops = {
261	.init = nfs4blocklayout_net_init,
262	.exit = nfs4blocklayout_net_exit,
263};
264
265int __init bl_init_pipefs(void)
266{
267	int ret;
268
269	ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
270	if (ret)
271		goto out;
272	ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
273	if (ret)
274		goto out_unregister_notifier;
275	return 0;
276
277out_unregister_notifier:
278	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
279out:
280	return ret;
281}
282
283void bl_cleanup_pipefs(void)
284{
285	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
286	unregister_pernet_subsys(&nfs4blocklayout_net_ops);
287}
288