1/*
2 *  Device operations for the pnfs client.
3 *
4 *  Copyright (c) 2002
5 *  The Regents of the University of Michigan
6 *  All Rights Reserved
7 *
8 *  Dean Hildebrand <dhildebz@umich.edu>
9 *  Garth Goodson   <Garth.Goodson@netapp.com>
10 *
11 *  Permission is granted to use, copy, create derivative works, and
12 *  redistribute this software and such derivative works for any purpose,
13 *  so long as the name of the University of Michigan is not used in
14 *  any advertising or publicity pertaining to the use or distribution
15 *  of this software without specific, written prior authorization. If
16 *  the above copyright notice or any other identification of the
17 *  University of Michigan is included in any copy of any portion of
18 *  this software, then the disclaimer below must also be included.
19 *
20 *  This software is provided as is, without representation or warranty
21 *  of any kind either express or implied, including without limitation
22 *  the implied warranties of merchantability, fitness for a particular
23 *  purpose, or noninfringement.  The Regents of the University of
24 *  Michigan shall not be liable for any damages, including special,
25 *  indirect, incidental, or consequential damages, with respect to any
26 *  claim arising out of or in connection with the use of the software,
27 *  even if it has been or is hereafter advised of the possibility of
28 *  such damages.
29 */
30
31#include <linux/export.h>
32#include <linux/nfs_fs.h>
33#include "nfs4session.h"
34#include "internal.h"
35#include "pnfs.h"
36
37#define NFSDBG_FACILITY		NFSDBG_PNFS
38
39/*
40 * Device ID RCU cache. A device ID is unique per server and layout type.
41 */
42#define NFS4_DEVICE_ID_HASH_BITS	5
43#define NFS4_DEVICE_ID_HASH_SIZE	(1 << NFS4_DEVICE_ID_HASH_BITS)
44#define NFS4_DEVICE_ID_HASH_MASK	(NFS4_DEVICE_ID_HASH_SIZE - 1)
45
46#define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)
47
48static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
49static DEFINE_SPINLOCK(nfs4_deviceid_lock);
50
51#ifdef NFS_DEBUG
52void
53nfs4_print_deviceid(const struct nfs4_deviceid *id)
54{
55	u32 *p = (u32 *)id;
56
57	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
58		p[0], p[1], p[2], p[3]);
59}
60EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
61#endif
62
63static inline u32
64nfs4_deviceid_hash(const struct nfs4_deviceid *id)
65{
66	unsigned char *cptr = (unsigned char *)id->data;
67	unsigned int nbytes = NFS4_DEVICEID4_SIZE;
68	u32 x = 0;
69
70	while (nbytes--) {
71		x *= 37;
72		x += *cptr++;
73	}
74	return x & NFS4_DEVICE_ID_HASH_MASK;
75}
76
77static struct nfs4_deviceid_node *
78_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
79		 const struct nfs_client *clp, const struct nfs4_deviceid *id,
80		 long hash)
81{
82	struct nfs4_deviceid_node *d;
83
84	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
85		if (d->ld == ld && d->nfs_client == clp &&
86		    !memcmp(&d->deviceid, id, sizeof(*id))) {
87			if (atomic_read(&d->ref))
88				return d;
89			else
90				continue;
91		}
92	return NULL;
93}
94
95static struct nfs4_deviceid_node *
96nfs4_get_device_info(struct nfs_server *server,
97		const struct nfs4_deviceid *dev_id,
98		struct rpc_cred *cred, gfp_t gfp_flags)
99{
100	struct nfs4_deviceid_node *d = NULL;
101	struct pnfs_device *pdev = NULL;
102	struct page **pages = NULL;
103	u32 max_resp_sz;
104	int max_pages;
105	int rc, i;
106
107	/*
108	 * Use the session max response size as the basis for setting
109	 * GETDEVICEINFO's maxcount
110	 */
111	max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
112	if (server->pnfs_curr_ld->max_deviceinfo_size &&
113	    server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
114		max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
115	max_pages = nfs_page_array_len(0, max_resp_sz);
116	dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
117		__func__, server, max_resp_sz, max_pages);
118
119	pdev = kzalloc(sizeof(*pdev), gfp_flags);
120	if (!pdev)
121		return NULL;
122
123	pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
124	if (!pages)
125		goto out_free_pdev;
126
127	for (i = 0; i < max_pages; i++) {
128		pages[i] = alloc_page(gfp_flags);
129		if (!pages[i])
130			goto out_free_pages;
131	}
132
133	memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
134	pdev->layout_type = server->pnfs_curr_ld->id;
135	pdev->pages = pages;
136	pdev->pgbase = 0;
137	pdev->pglen = max_resp_sz;
138	pdev->mincount = 0;
139	pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
140
141	rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
142	dprintk("%s getdevice info returns %d\n", __func__, rc);
143	if (rc)
144		goto out_free_pages;
145
146	/*
147	 * Found new device, need to decode it and then add it to the
148	 * list of known devices for this mountpoint.
149	 */
150	d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
151			gfp_flags);
152	if (d && pdev->nocache)
153		set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
154
155out_free_pages:
156	for (i = 0; i < max_pages; i++)
157		__free_page(pages[i]);
158	kfree(pages);
159out_free_pdev:
160	kfree(pdev);
161	dprintk("<-- %s d %p\n", __func__, d);
162	return d;
163}
164
165/*
166 * Lookup a deviceid in cache and get a reference count on it if found
167 *
168 * @clp nfs_client associated with deviceid
169 * @id deviceid to look up
170 */
171static struct nfs4_deviceid_node *
172__nfs4_find_get_deviceid(struct nfs_server *server,
173		const struct nfs4_deviceid *id, long hash)
174{
175	struct nfs4_deviceid_node *d;
176
177	rcu_read_lock();
178	d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
179			hash);
180	if (d != NULL && !atomic_inc_not_zero(&d->ref))
181		d = NULL;
182	rcu_read_unlock();
183	return d;
184}
185
186struct nfs4_deviceid_node *
187nfs4_find_get_deviceid(struct nfs_server *server,
188		const struct nfs4_deviceid *id, struct rpc_cred *cred,
189		gfp_t gfp_mask)
190{
191	long hash = nfs4_deviceid_hash(id);
192	struct nfs4_deviceid_node *d, *new;
193
194	d = __nfs4_find_get_deviceid(server, id, hash);
195	if (d)
196		return d;
197
198	new = nfs4_get_device_info(server, id, cred, gfp_mask);
199	if (!new)
200		return new;
201
202	spin_lock(&nfs4_deviceid_lock);
203	d = __nfs4_find_get_deviceid(server, id, hash);
204	if (d) {
205		spin_unlock(&nfs4_deviceid_lock);
206		server->pnfs_curr_ld->free_deviceid_node(new);
207		return d;
208	}
209	hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
210	atomic_inc(&new->ref);
211	spin_unlock(&nfs4_deviceid_lock);
212
213	return new;
214}
215EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
216
217/*
218 * Remove a deviceid from cache
219 *
220 * @clp nfs_client associated with deviceid
221 * @id the deviceid to unhash
222 *
223 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
224 */
225void
226nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
227			 const struct nfs_client *clp, const struct nfs4_deviceid *id)
228{
229	struct nfs4_deviceid_node *d;
230
231	spin_lock(&nfs4_deviceid_lock);
232	rcu_read_lock();
233	d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
234	rcu_read_unlock();
235	if (!d) {
236		spin_unlock(&nfs4_deviceid_lock);
237		return;
238	}
239	hlist_del_init_rcu(&d->node);
240	clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
241	spin_unlock(&nfs4_deviceid_lock);
242
243	/* balance the initial ref set in pnfs_insert_deviceid */
244	nfs4_put_deviceid_node(d);
245}
246EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
247
248void
249nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
250			const struct nfs4_deviceid *id)
251{
252	INIT_HLIST_NODE(&d->node);
253	INIT_HLIST_NODE(&d->tmpnode);
254	d->ld = server->pnfs_curr_ld;
255	d->nfs_client = server->nfs_client;
256	d->flags = 0;
257	d->deviceid = *id;
258	atomic_set(&d->ref, 1);
259}
260EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
261
262/*
263 * Dereference a deviceid node and delete it when its reference count drops
264 * to zero.
265 *
266 * @d deviceid node to put
267 *
268 * return true iff the node was deleted
269 * Note that since the test for d->ref == 0 is sufficient to establish
270 * that the node is no longer hashed in the global device id cache.
271 */
272bool
273nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
274{
275	if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
276		if (atomic_add_unless(&d->ref, -1, 2))
277			return false;
278		nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
279	}
280	if (!atomic_dec_and_test(&d->ref))
281		return false;
282	d->ld->free_deviceid_node(d);
283	return true;
284}
285EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
286
287void
288nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
289{
290	node->timestamp_unavailable = jiffies;
291	set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
292}
293EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
294
295bool
296nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
297{
298	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
299		unsigned long start, end;
300
301		end = jiffies;
302		start = end - PNFS_DEVICE_RETRY_TIMEOUT;
303		if (time_in_range(node->timestamp_unavailable, start, end))
304			return true;
305		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
306	}
307	return false;
308}
309EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
310
311static void
312_deviceid_purge_client(const struct nfs_client *clp, long hash)
313{
314	struct nfs4_deviceid_node *d;
315	HLIST_HEAD(tmp);
316
317	spin_lock(&nfs4_deviceid_lock);
318	rcu_read_lock();
319	hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
320		if (d->nfs_client == clp && atomic_read(&d->ref)) {
321			hlist_del_init_rcu(&d->node);
322			hlist_add_head(&d->tmpnode, &tmp);
323			clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
324		}
325	rcu_read_unlock();
326	spin_unlock(&nfs4_deviceid_lock);
327
328	if (hlist_empty(&tmp))
329		return;
330
331	while (!hlist_empty(&tmp)) {
332		d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
333		hlist_del(&d->tmpnode);
334		nfs4_put_deviceid_node(d);
335	}
336}
337
338void
339nfs4_deviceid_purge_client(const struct nfs_client *clp)
340{
341	long h;
342
343	if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
344		return;
345	for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
346		_deviceid_purge_client(clp, h);
347}
348
349/*
350 * Stop use of all deviceids associated with an nfs_client
351 */
352void
353nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
354{
355	struct nfs4_deviceid_node *d;
356	int i;
357
358	rcu_read_lock();
359	for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
360		hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
361			if (d->nfs_client == clp)
362				set_bit(NFS_DEVICEID_INVALID, &d->flags);
363	}
364	rcu_read_unlock();
365}
366