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/genhd.h>
31#include <linux/blkdev.h>
32
33#include "blocklayout.h"
34
35#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
36
37static void
38nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
39{
40	int i;
41
42	*p++ = cpu_to_be32(1);
43	*p++ = cpu_to_be32(b->type);
44	*p++ = cpu_to_be32(b->simple.nr_sigs);
45	for (i = 0; i < b->simple.nr_sigs; i++) {
46		p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
47		p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
48					 b->simple.sigs[i].sig_len);
49	}
50}
51
52dev_t
53bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
54		gfp_t gfp_mask)
55{
56	struct net *net = server->nfs_client->cl_net;
57	struct nfs_net *nn = net_generic(net, nfs_net_id);
58	struct bl_dev_msg *reply = &nn->bl_mount_reply;
59	struct bl_pipe_msg bl_pipe_msg;
60	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
61	struct bl_msg_hdr *bl_msg;
62	DECLARE_WAITQUEUE(wq, current);
63	dev_t dev = 0;
64	int rc;
65
66	dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
67
68	mutex_lock(&nn->bl_mutex);
69	bl_pipe_msg.bl_wq = &nn->bl_wq;
70
71	b->simple.len += 4;	/* single volume */
72	if (b->simple.len > PAGE_SIZE)
73		goto out_unlock;
74
75	memset(msg, 0, sizeof(*msg));
76	msg->len = sizeof(*bl_msg) + b->simple.len;
77	msg->data = kzalloc(msg->len, gfp_mask);
78	if (!msg->data)
79		goto out_free_data;
80
81	bl_msg = msg->data;
82	bl_msg->type = BL_DEVICE_MOUNT,
83	bl_msg->totallen = b->simple.len;
84	nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
85
86	dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
87	add_wait_queue(&nn->bl_wq, &wq);
88	rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
89	if (rc < 0) {
90		remove_wait_queue(&nn->bl_wq, &wq);
91		goto out_free_data;
92	}
93
94	set_current_state(TASK_UNINTERRUPTIBLE);
95	schedule();
96	remove_wait_queue(&nn->bl_wq, &wq);
97
98	if (reply->status != BL_DEVICE_REQUEST_PROC) {
99		printk(KERN_WARNING "%s failed to decode device: %d\n",
100			__func__, reply->status);
101		goto out_free_data;
102	}
103
104	dev = MKDEV(reply->major, reply->minor);
105out_free_data:
106	kfree(msg->data);
107out_unlock:
108	mutex_unlock(&nn->bl_mutex);
109	return dev;
110}
111
112static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
113			 size_t mlen)
114{
115	struct nfs_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
116					 nfs_net_id);
117
118	if (mlen != sizeof (struct bl_dev_msg))
119		return -EINVAL;
120
121	if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
122		return -EFAULT;
123
124	wake_up(&nn->bl_wq);
125
126	return mlen;
127}
128
129static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
130{
131	struct bl_pipe_msg *bl_pipe_msg =
132		container_of(msg, struct bl_pipe_msg, msg);
133
134	if (msg->errno >= 0)
135		return;
136	wake_up(bl_pipe_msg->bl_wq);
137}
138
139static const struct rpc_pipe_ops bl_upcall_ops = {
140	.upcall		= rpc_pipe_generic_upcall,
141	.downcall	= bl_pipe_downcall,
142	.destroy_msg	= bl_pipe_destroy_msg,
143};
144
145static struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
146					    struct rpc_pipe *pipe)
147{
148	struct dentry *dir, *dentry;
149
150	dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
151	if (dir == NULL)
152		return ERR_PTR(-ENOENT);
153	dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
154	dput(dir);
155	return dentry;
156}
157
158static void nfs4blocklayout_unregister_sb(struct super_block *sb,
159					  struct rpc_pipe *pipe)
160{
161	if (pipe->dentry)
162		rpc_unlink(pipe->dentry);
163}
164
165static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
166			   void *ptr)
167{
168	struct super_block *sb = ptr;
169	struct net *net = sb->s_fs_info;
170	struct nfs_net *nn = net_generic(net, nfs_net_id);
171	struct dentry *dentry;
172	int ret = 0;
173
174	if (!try_module_get(THIS_MODULE))
175		return 0;
176
177	if (nn->bl_device_pipe == NULL) {
178		module_put(THIS_MODULE);
179		return 0;
180	}
181
182	switch (event) {
183	case RPC_PIPEFS_MOUNT:
184		dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
185		if (IS_ERR(dentry)) {
186			ret = PTR_ERR(dentry);
187			break;
188		}
189		nn->bl_device_pipe->dentry = dentry;
190		break;
191	case RPC_PIPEFS_UMOUNT:
192		if (nn->bl_device_pipe->dentry)
193			nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
194		break;
195	default:
196		ret = -ENOTSUPP;
197		break;
198	}
199	module_put(THIS_MODULE);
200	return ret;
201}
202
203static struct notifier_block nfs4blocklayout_block = {
204	.notifier_call = rpc_pipefs_event,
205};
206
207static struct dentry *nfs4blocklayout_register_net(struct net *net,
208						   struct rpc_pipe *pipe)
209{
210	struct super_block *pipefs_sb;
211	struct dentry *dentry;
212
213	pipefs_sb = rpc_get_sb_net(net);
214	if (!pipefs_sb)
215		return NULL;
216	dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
217	rpc_put_sb_net(net);
218	return dentry;
219}
220
221static void nfs4blocklayout_unregister_net(struct net *net,
222					   struct rpc_pipe *pipe)
223{
224	struct super_block *pipefs_sb;
225
226	pipefs_sb = rpc_get_sb_net(net);
227	if (pipefs_sb) {
228		nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
229		rpc_put_sb_net(net);
230	}
231}
232
233static int nfs4blocklayout_net_init(struct net *net)
234{
235	struct nfs_net *nn = net_generic(net, nfs_net_id);
236	struct dentry *dentry;
237
238	mutex_init(&nn->bl_mutex);
239	init_waitqueue_head(&nn->bl_wq);
240	nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
241	if (IS_ERR(nn->bl_device_pipe))
242		return PTR_ERR(nn->bl_device_pipe);
243	dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
244	if (IS_ERR(dentry)) {
245		rpc_destroy_pipe_data(nn->bl_device_pipe);
246		return PTR_ERR(dentry);
247	}
248	nn->bl_device_pipe->dentry = dentry;
249	return 0;
250}
251
252static void nfs4blocklayout_net_exit(struct net *net)
253{
254	struct nfs_net *nn = net_generic(net, nfs_net_id);
255
256	nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
257	rpc_destroy_pipe_data(nn->bl_device_pipe);
258	nn->bl_device_pipe = NULL;
259}
260
261static struct pernet_operations nfs4blocklayout_net_ops = {
262	.init = nfs4blocklayout_net_init,
263	.exit = nfs4blocklayout_net_exit,
264};
265
266int __init bl_init_pipefs(void)
267{
268	int ret;
269
270	ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
271	if (ret)
272		goto out;
273	ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
274	if (ret)
275		goto out_unregister_notifier;
276	return 0;
277
278out_unregister_notifier:
279	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
280out:
281	return ret;
282}
283
284void __exit bl_cleanup_pipefs(void)
285{
286	rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
287	unregister_pernet_subsys(&nfs4blocklayout_net_ops);
288}
289