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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 <[email protected]>
9 * Garth Goodson <[email protected]>
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#include "nfs4trace.h"
38
39#define NFSDBG_FACILITY NFSDBG_PNFS
40
41/*
42 * Device ID RCU cache. A device ID is unique per server and layout type.
43 */
44#define NFS4_DEVICE_ID_HASH_BITS 5
45#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
46#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
47
48
49static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
50static DEFINE_SPINLOCK(nfs4_deviceid_lock);
51
52#ifdef NFS_DEBUG
53void
54nfs4_print_deviceid(const struct nfs4_deviceid *id)
55{
56 u32 *p = (u32 *)id;
57
58 dprintk("%s: device id= [%x%x%x%x]\n", __func__,
59 p[0], p[1], p[2], p[3]);
60}
61EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
62#endif
63
64static inline u32
65nfs4_deviceid_hash(const struct nfs4_deviceid *id)
66{
67 unsigned char *cptr = (unsigned char *)id->data;
68 unsigned int nbytes = NFS4_DEVICEID4_SIZE;
69 u32 x = 0;
70
71 while (nbytes--) {
72 x *= 37;
73 x += *cptr++;
74 }
75 return x & NFS4_DEVICE_ID_HASH_MASK;
76}
77
78static struct nfs4_deviceid_node *
79_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
80 const struct nfs_client *clp, const struct nfs4_deviceid *id,
81 long hash)
82{
83 struct nfs4_deviceid_node *d;
84
85 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
86 if (d->ld == ld && d->nfs_client == clp &&
87 !memcmp(&d->deviceid, id, sizeof(*id))) {
88 if (atomic_read(&d->ref))
89 return d;
90 else
91 continue;
92 }
93 return NULL;
94}
95
96static struct nfs4_deviceid_node *
97nfs4_get_device_info(struct nfs_server *server,
98 const struct nfs4_deviceid *dev_id,
99 const struct cred *cred, gfp_t gfp_flags)
100{
101 struct nfs4_deviceid_node *d = NULL;
102 struct pnfs_device *pdev = NULL;
103 struct page **pages = NULL;
104 u32 max_resp_sz;
105 int max_pages;
106 int rc, i;
107
108 /*
109 * Use the session max response size as the basis for setting
110 * GETDEVICEINFO's maxcount
111 */
112 max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
113 max_pages = nfs_page_array_len(0, max_resp_sz);
114 dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
115 __func__, server, max_resp_sz, max_pages);
116
117 pdev = kzalloc_obj(*pdev, gfp_flags);
118 if (!pdev)
119 return NULL;
120
121 pages = kzalloc_objs(struct page *, max_pages, gfp_flags);
122 if (!pages)
123 goto out_free_pdev;
124
125 for (i = 0; i < max_pages; i++) {
126 pages[i] = alloc_page(gfp_flags);
127 if (!pages[i])
128 goto out_free_pages;
129 }
130
131 memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
132 pdev->layout_type = server->pnfs_curr_ld->id;
133 pdev->pages = pages;
134 pdev->pgbase = 0;
135 pdev->pglen = max_resp_sz;
136 pdev->mincount = 0;
137 pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
138
139 rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
140 dprintk("%s getdevice info returns %d\n", __func__, rc);
141 if (rc)
142 goto out_free_pages;
143
144 /*
145 * Found new device, need to decode it and then add it to the
146 * list of known devices for this mountpoint.
147 */
148 d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
149 gfp_flags);
150 if (d && pdev->nocache)
151 set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
152
153out_free_pages:
154 while (--i >= 0)
155 __free_page(pages[i]);
156 kfree(pages);
157out_free_pdev:
158 kfree(pdev);
159 dprintk("<-- %s d %p\n", __func__, d);
160 return d;
161}
162
163/*
164 * Lookup a deviceid in cache and get a reference count on it if found
165 *
166 * @clp nfs_client associated with deviceid
167 * @id deviceid to look up
168 */
169static struct nfs4_deviceid_node *
170__nfs4_find_get_deviceid(struct nfs_server *server,
171 const struct nfs4_deviceid *id, long hash)
172{
173 struct nfs4_deviceid_node *d;
174
175 rcu_read_lock();
176 d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
177 hash);
178 if (d != NULL && !atomic_inc_not_zero(&d->ref))
179 d = NULL;
180 rcu_read_unlock();
181 return d;
182}
183
184struct nfs4_deviceid_node *
185nfs4_find_get_deviceid(struct nfs_server *server,
186 const struct nfs4_deviceid *id, const struct cred *cred,
187 gfp_t gfp_mask)
188{
189 long hash = nfs4_deviceid_hash(id);
190 struct nfs4_deviceid_node *d, *new;
191
192 d = __nfs4_find_get_deviceid(server, id, hash);
193 if (d)
194 goto found;
195
196 new = nfs4_get_device_info(server, id, cred, gfp_mask);
197 if (!new) {
198 trace_nfs4_find_deviceid(server, id, -ENOENT);
199 return new;
200 }
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 } else {
208 atomic_inc(&new->ref);
209 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
210 spin_unlock(&nfs4_deviceid_lock);
211 d = new;
212 }
213found:
214 trace_nfs4_find_deviceid(server, id, 0);
215 return d;
216}
217EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
218
219/*
220 * Remove a deviceid from cache
221 *
222 * @clp nfs_client associated with deviceid
223 * @id the deviceid to unhash
224 *
225 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
226 */
227void
228nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
229 const struct nfs_client *clp, const struct nfs4_deviceid *id)
230{
231 struct nfs4_deviceid_node *d;
232
233 spin_lock(&nfs4_deviceid_lock);
234 rcu_read_lock();
235 d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
236 rcu_read_unlock();
237 if (!d) {
238 spin_unlock(&nfs4_deviceid_lock);
239 return;
240 }
241 hlist_del_init_rcu(&d->node);
242 clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
243 spin_unlock(&nfs4_deviceid_lock);
244
245 /* balance the initial ref set in pnfs_insert_deviceid */
246 nfs4_put_deviceid_node(d);
247}
248EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
249
250void
251nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
252 const struct nfs4_deviceid *id)
253{
254 INIT_HLIST_NODE(&d->node);
255 INIT_HLIST_NODE(&d->tmpnode);
256 d->ld = server->pnfs_curr_ld;
257 d->nfs_client = server->nfs_client;
258 d->flags = 0;
259 d->deviceid = *id;
260 atomic_set(&d->ref, 1);
261}
262EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
263
264/*
265 * Dereference a deviceid node and delete it when its reference count drops
266 * to zero.
267 *
268 * @d deviceid node to put
269 *
270 * return true iff the node was deleted
271 * Note that since the test for d->ref == 0 is sufficient to establish
272 * that the node is no longer hashed in the global device id cache.
273 */
274bool
275nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
276{
277 if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
278 if (atomic_add_unless(&d->ref, -1, 2))
279 return false;
280 nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
281 }
282 if (!atomic_dec_and_test(&d->ref))
283 return false;
284 trace_nfs4_deviceid_free(d->nfs_client, &d->deviceid);
285 d->ld->free_deviceid_node(d);
286 return true;
287}
288EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
289
290void
291nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)
292{
293 if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
294 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
295 smp_mb__after_atomic();
296 }
297}
298EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);
299
300void
301nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
302{
303 node->timestamp_unavailable = jiffies;
304 smp_mb__before_atomic();
305 set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
306 smp_mb__after_atomic();
307}
308EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
309
310bool
311nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
312{
313 if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
314 unsigned long start, end;
315
316 end = jiffies;
317 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
318 if (time_in_range(node->timestamp_unavailable, start, end))
319 return true;
320 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
321 smp_mb__after_atomic();
322 }
323 return false;
324}
325EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
326
327static void
328_deviceid_purge_client(const struct nfs_client *clp, long hash)
329{
330 struct nfs4_deviceid_node *d;
331 HLIST_HEAD(tmp);
332
333 spin_lock(&nfs4_deviceid_lock);
334 rcu_read_lock();
335 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
336 if (d->nfs_client == clp && atomic_read(&d->ref)) {
337 hlist_del_init_rcu(&d->node);
338 hlist_add_head(&d->tmpnode, &tmp);
339 clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
340 }
341 rcu_read_unlock();
342 spin_unlock(&nfs4_deviceid_lock);
343
344 if (hlist_empty(&tmp))
345 return;
346
347 while (!hlist_empty(&tmp)) {
348 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
349 hlist_del(&d->tmpnode);
350 nfs4_put_deviceid_node(d);
351 }
352}
353
354void
355nfs4_deviceid_purge_client(const struct nfs_client *clp)
356{
357 long h;
358
359 if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
360 return;
361 for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
362 _deviceid_purge_client(clp, h);
363}
364
365/*
366 * Stop use of all deviceids associated with an nfs_client
367 */
368void
369nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
370{
371 struct nfs4_deviceid_node *d;
372 int i;
373
374 rcu_read_lock();
375 for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
376 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
377 if (d->nfs_client == clp)
378 set_bit(NFS_DEVICEID_INVALID, &d->flags);
379 }
380 rcu_read_unlock();
381}