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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * Request reply cache. This is currently a global cache, but this may |
4 | * change in the future and be a per-client cache. | |
5 | * | |
6 | * This code is heavily inspired by the 44BSD implementation, although | |
7 | * it does things a bit differently. | |
8 | * | |
9 | * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> | |
10 | */ | |
11 | ||
3ba75830 | 12 | #include <linux/sunrpc/svc_xprt.h> |
5a0e3ad6 | 13 | #include <linux/slab.h> |
8f97514b | 14 | #include <linux/vmalloc.h> |
5976687a | 15 | #include <linux/sunrpc/addr.h> |
0338dd15 | 16 | #include <linux/highmem.h> |
0733c7ba JL |
17 | #include <linux/log2.h> |
18 | #include <linux/hash.h> | |
01a7decf | 19 | #include <net/checksum.h> |
5a0e3ad6 | 20 | |
9a74af21 BH |
21 | #include "nfsd.h" |
22 | #include "cache.h" | |
0b175b18 | 23 | #include "trace.h" |
0338dd15 | 24 | |
0733c7ba JL |
25 | /* |
26 | * We use this value to determine the number of hash buckets from the max | |
27 | * cache size, the idea being that when the cache is at its maximum number | |
28 | * of entries, then this should be the average number of entries per bucket. | |
29 | */ | |
30 | #define TARGET_BUCKET_SIZE 64 | |
1da177e4 | 31 | |
7142b98d | 32 | struct nfsd_drc_bucket { |
736c6625 | 33 | struct rb_root rb_head; |
bedd4b61 | 34 | struct list_head lru_head; |
89a26b3d | 35 | spinlock_t cache_lock; |
7142b98d TM |
36 | }; |
37 | ||
027690c7 BF |
38 | static struct kmem_cache *drc_slab; |
39 | ||
1da177e4 | 40 | static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec); |
1ab6c499 DC |
41 | static unsigned long nfsd_reply_cache_count(struct shrinker *shrink, |
42 | struct shrink_control *sc); | |
43 | static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink, | |
44 | struct shrink_control *sc); | |
b4e7f2c9 | 45 | |
0338dd15 JL |
46 | /* |
47 | * Put a cap on the size of the DRC based on the amount of available | |
48 | * low memory in the machine. | |
49 | * | |
50 | * 64MB: 8192 | |
51 | * 128MB: 11585 | |
52 | * 256MB: 16384 | |
53 | * 512MB: 23170 | |
54 | * 1GB: 32768 | |
55 | * 2GB: 46340 | |
56 | * 4GB: 65536 | |
57 | * 8GB: 92681 | |
58 | * 16GB: 131072 | |
59 | * | |
60 | * ...with a hard cap of 256k entries. In the worst case, each entry will be | |
61 | * ~1k, so the above numbers should give a rough max of the amount of memory | |
62 | * used in k. | |
3ba75830 BF |
63 | * |
64 | * XXX: these limits are per-container, so memory used will increase | |
65 | * linearly with number of containers. Maybe that's OK. | |
0338dd15 JL |
66 | */ |
67 | static unsigned int | |
68 | nfsd_cache_size_limit(void) | |
69 | { | |
70 | unsigned int limit; | |
ca79b0c2 | 71 | unsigned long low_pages = totalram_pages() - totalhigh_pages(); |
0338dd15 JL |
72 | |
73 | limit = (16 * int_sqrt(low_pages)) << (PAGE_SHIFT-10); | |
74 | return min_t(unsigned int, limit, 256*1024); | |
75 | } | |
76 | ||
0733c7ba JL |
77 | /* |
78 | * Compute the number of hash buckets we need. Divide the max cachesize by | |
79 | * the "target" max bucket size, and round up to next power of two. | |
80 | */ | |
81 | static unsigned int | |
82 | nfsd_hashsize(unsigned int limit) | |
83 | { | |
84 | return roundup_pow_of_two(limit / TARGET_BUCKET_SIZE); | |
85 | } | |
86 | ||
7142b98d | 87 | static u32 |
3ba75830 | 88 | nfsd_cache_hash(__be32 xid, struct nfsd_net *nn) |
7142b98d | 89 | { |
3ba75830 | 90 | return hash_32(be32_to_cpu(xid), nn->maskbits); |
7142b98d TM |
91 | } |
92 | ||
f09841fd | 93 | static struct svc_cacherep * |
3ba75830 BF |
94 | nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum, |
95 | struct nfsd_net *nn) | |
1da177e4 LT |
96 | { |
97 | struct svc_cacherep *rp; | |
1da177e4 | 98 | |
027690c7 | 99 | rp = kmem_cache_alloc(drc_slab, GFP_KERNEL); |
f09841fd | 100 | if (rp) { |
1da177e4 LT |
101 | rp->c_state = RC_UNUSED; |
102 | rp->c_type = RC_NOCACHE; | |
736c6625 | 103 | RB_CLEAR_NODE(&rp->c_node); |
f09841fd | 104 | INIT_LIST_HEAD(&rp->c_lru); |
76ecec21 | 105 | |
ed00c2f6 TM |
106 | memset(&rp->c_key, 0, sizeof(rp->c_key)); |
107 | rp->c_key.k_xid = rqstp->rq_xid; | |
108 | rp->c_key.k_proc = rqstp->rq_proc; | |
109 | rpc_copy_addr((struct sockaddr *)&rp->c_key.k_addr, svc_addr(rqstp)); | |
110 | rpc_set_port((struct sockaddr *)&rp->c_key.k_addr, rpc_get_port(svc_addr(rqstp))); | |
111 | rp->c_key.k_prot = rqstp->rq_prot; | |
112 | rp->c_key.k_vers = rqstp->rq_vers; | |
113 | rp->c_key.k_len = rqstp->rq_arg.len; | |
114 | rp->c_key.k_csum = csum; | |
1da177e4 | 115 | } |
f09841fd JL |
116 | return rp; |
117 | } | |
1da177e4 | 118 | |
f09841fd | 119 | static void |
3ba75830 BF |
120 | nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp, |
121 | struct nfsd_net *nn) | |
f09841fd | 122 | { |
6c6910cd | 123 | if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) { |
3ba75830 | 124 | nn->drc_mem_usage -= rp->c_replvec.iov_len; |
f09841fd | 125 | kfree(rp->c_replvec.iov_base); |
6c6910cd | 126 | } |
76ecec21 | 127 | if (rp->c_state != RC_UNUSED) { |
736c6625 | 128 | rb_erase(&rp->c_node, &b->rb_head); |
76ecec21 | 129 | list_del(&rp->c_lru); |
3ba75830 BF |
130 | atomic_dec(&nn->num_drc_entries); |
131 | nn->drc_mem_usage -= sizeof(*rp); | |
76ecec21 | 132 | } |
027690c7 | 133 | kmem_cache_free(drc_slab, rp); |
f09841fd JL |
134 | } |
135 | ||
2c6b691c | 136 | static void |
3ba75830 BF |
137 | nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp, |
138 | struct nfsd_net *nn) | |
2c6b691c | 139 | { |
89a26b3d | 140 | spin_lock(&b->cache_lock); |
3ba75830 | 141 | nfsd_reply_cache_free_locked(b, rp, nn); |
89a26b3d | 142 | spin_unlock(&b->cache_lock); |
2c6b691c JL |
143 | } |
144 | ||
027690c7 BF |
145 | int nfsd_drc_slab_create(void) |
146 | { | |
147 | drc_slab = kmem_cache_create("nfsd_drc", | |
148 | sizeof(struct svc_cacherep), 0, 0, NULL); | |
149 | return drc_slab ? 0: -ENOMEM; | |
150 | } | |
151 | ||
152 | void nfsd_drc_slab_free(void) | |
153 | { | |
154 | kmem_cache_destroy(drc_slab); | |
155 | } | |
156 | ||
3ba75830 | 157 | int nfsd_reply_cache_init(struct nfsd_net *nn) |
f09841fd | 158 | { |
0733c7ba | 159 | unsigned int hashsize; |
bedd4b61 | 160 | unsigned int i; |
a68465c9 | 161 | int status = 0; |
0733c7ba | 162 | |
3ba75830 BF |
163 | nn->max_drc_entries = nfsd_cache_size_limit(); |
164 | atomic_set(&nn->num_drc_entries, 0); | |
165 | hashsize = nfsd_hashsize(nn->max_drc_entries); | |
166 | nn->maskbits = ilog2(hashsize); | |
ac534ff2 | 167 | |
3ba75830 BF |
168 | nn->nfsd_reply_cache_shrinker.scan_objects = nfsd_reply_cache_scan; |
169 | nn->nfsd_reply_cache_shrinker.count_objects = nfsd_reply_cache_count; | |
170 | nn->nfsd_reply_cache_shrinker.seeks = 1; | |
171 | status = register_shrinker(&nn->nfsd_reply_cache_shrinker); | |
a68465c9 | 172 | if (status) |
689d7ba4 | 173 | goto out_nomem; |
a68465c9 | 174 | |
8c38b705 RR |
175 | nn->drc_hashtbl = kvzalloc(array_size(hashsize, |
176 | sizeof(*nn->drc_hashtbl)), GFP_KERNEL); | |
177 | if (!nn->drc_hashtbl) | |
178 | goto out_shrinker; | |
8f97514b | 179 | |
89a26b3d | 180 | for (i = 0; i < hashsize; i++) { |
3ba75830 BF |
181 | INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head); |
182 | spin_lock_init(&nn->drc_hashtbl[i].cache_lock); | |
89a26b3d | 183 | } |
3ba75830 | 184 | nn->drc_hashsize = hashsize; |
1da177e4 | 185 | |
d5c3428b | 186 | return 0; |
689d7ba4 BF |
187 | out_shrinker: |
188 | unregister_shrinker(&nn->nfsd_reply_cache_shrinker); | |
d5c3428b BF |
189 | out_nomem: |
190 | printk(KERN_ERR "nfsd: failed to allocate reply cache\n"); | |
d5c3428b | 191 | return -ENOMEM; |
1da177e4 LT |
192 | } |
193 | ||
3ba75830 | 194 | void nfsd_reply_cache_shutdown(struct nfsd_net *nn) |
1da177e4 LT |
195 | { |
196 | struct svc_cacherep *rp; | |
bedd4b61 | 197 | unsigned int i; |
1da177e4 | 198 | |
3ba75830 | 199 | unregister_shrinker(&nn->nfsd_reply_cache_shrinker); |
aca8a23d | 200 | |
3ba75830 BF |
201 | for (i = 0; i < nn->drc_hashsize; i++) { |
202 | struct list_head *head = &nn->drc_hashtbl[i].lru_head; | |
bedd4b61 TM |
203 | while (!list_empty(head)) { |
204 | rp = list_first_entry(head, struct svc_cacherep, c_lru); | |
3ba75830 BF |
205 | nfsd_reply_cache_free_locked(&nn->drc_hashtbl[i], |
206 | rp, nn); | |
bedd4b61 | 207 | } |
1da177e4 LT |
208 | } |
209 | ||
3ba75830 BF |
210 | kvfree(nn->drc_hashtbl); |
211 | nn->drc_hashtbl = NULL; | |
212 | nn->drc_hashsize = 0; | |
8a8bc40d | 213 | |
1da177e4 LT |
214 | } |
215 | ||
216 | /* | |
aca8a23d JL |
217 | * Move cache entry to end of LRU list, and queue the cleaner to run if it's |
218 | * not already scheduled. | |
1da177e4 LT |
219 | */ |
220 | static void | |
bedd4b61 | 221 | lru_put_end(struct nfsd_drc_bucket *b, struct svc_cacherep *rp) |
1da177e4 | 222 | { |
56c2548b | 223 | rp->c_timestamp = jiffies; |
bedd4b61 | 224 | list_move_tail(&rp->c_lru, &b->lru_head); |
1da177e4 LT |
225 | } |
226 | ||
1ab6c499 | 227 | static long |
3ba75830 | 228 | prune_bucket(struct nfsd_drc_bucket *b, struct nfsd_net *nn) |
aca8a23d JL |
229 | { |
230 | struct svc_cacherep *rp, *tmp; | |
1ab6c499 | 231 | long freed = 0; |
aca8a23d | 232 | |
bedd4b61 | 233 | list_for_each_entry_safe(rp, tmp, &b->lru_head, c_lru) { |
1b19453d JL |
234 | /* |
235 | * Don't free entries attached to calls that are still | |
236 | * in-progress, but do keep scanning the list. | |
237 | */ | |
238 | if (rp->c_state == RC_INPROG) | |
239 | continue; | |
3ba75830 | 240 | if (atomic_read(&nn->num_drc_entries) <= nn->max_drc_entries && |
1b19453d | 241 | time_before(jiffies, rp->c_timestamp + RC_EXPIRE)) |
aca8a23d | 242 | break; |
3ba75830 | 243 | nfsd_reply_cache_free_locked(b, rp, nn); |
1ab6c499 | 244 | freed++; |
aca8a23d | 245 | } |
bedd4b61 TM |
246 | return freed; |
247 | } | |
248 | ||
249 | /* | |
250 | * Walk the LRU list and prune off entries that are older than RC_EXPIRE. | |
251 | * Also prune the oldest ones when the total exceeds the max number of entries. | |
252 | */ | |
253 | static long | |
3ba75830 | 254 | prune_cache_entries(struct nfsd_net *nn) |
bedd4b61 TM |
255 | { |
256 | unsigned int i; | |
257 | long freed = 0; | |
bedd4b61 | 258 | |
3ba75830 BF |
259 | for (i = 0; i < nn->drc_hashsize; i++) { |
260 | struct nfsd_drc_bucket *b = &nn->drc_hashtbl[i]; | |
bedd4b61 | 261 | |
89a26b3d TM |
262 | if (list_empty(&b->lru_head)) |
263 | continue; | |
264 | spin_lock(&b->cache_lock); | |
3ba75830 | 265 | freed += prune_bucket(b, nn); |
89a26b3d | 266 | spin_unlock(&b->cache_lock); |
bedd4b61 | 267 | } |
1ab6c499 | 268 | return freed; |
aca8a23d JL |
269 | } |
270 | ||
1ab6c499 DC |
271 | static unsigned long |
272 | nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc) | |
b4e7f2c9 | 273 | { |
3ba75830 BF |
274 | struct nfsd_net *nn = container_of(shrink, |
275 | struct nfsd_net, nfsd_reply_cache_shrinker); | |
276 | ||
277 | return atomic_read(&nn->num_drc_entries); | |
b4e7f2c9 JL |
278 | } |
279 | ||
1ab6c499 DC |
280 | static unsigned long |
281 | nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc) | |
282 | { | |
3ba75830 BF |
283 | struct nfsd_net *nn = container_of(shrink, |
284 | struct nfsd_net, nfsd_reply_cache_shrinker); | |
285 | ||
286 | return prune_cache_entries(nn); | |
1ab6c499 | 287 | } |
01a7decf JL |
288 | /* |
289 | * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes | |
290 | */ | |
291 | static __wsum | |
292 | nfsd_cache_csum(struct svc_rqst *rqstp) | |
293 | { | |
294 | int idx; | |
295 | unsigned int base; | |
296 | __wsum csum; | |
297 | struct xdr_buf *buf = &rqstp->rq_arg; | |
298 | const unsigned char *p = buf->head[0].iov_base; | |
299 | size_t csum_len = min_t(size_t, buf->head[0].iov_len + buf->page_len, | |
300 | RC_CSUMLEN); | |
301 | size_t len = min(buf->head[0].iov_len, csum_len); | |
302 | ||
303 | /* rq_arg.head first */ | |
304 | csum = csum_partial(p, len, 0); | |
305 | csum_len -= len; | |
306 | ||
307 | /* Continue into page array */ | |
308 | idx = buf->page_base / PAGE_SIZE; | |
309 | base = buf->page_base & ~PAGE_MASK; | |
310 | while (csum_len) { | |
311 | p = page_address(buf->pages[idx]) + base; | |
56edc86b | 312 | len = min_t(size_t, PAGE_SIZE - base, csum_len); |
01a7decf JL |
313 | csum = csum_partial(p, len, csum); |
314 | csum_len -= len; | |
315 | base = 0; | |
316 | ++idx; | |
317 | } | |
318 | return csum; | |
319 | } | |
320 | ||
ed00c2f6 | 321 | static int |
3ba75830 BF |
322 | nfsd_cache_key_cmp(const struct svc_cacherep *key, |
323 | const struct svc_cacherep *rp, struct nfsd_net *nn) | |
9dc56143 | 324 | { |
ed00c2f6 | 325 | if (key->c_key.k_xid == rp->c_key.k_xid && |
0b175b18 | 326 | key->c_key.k_csum != rp->c_key.k_csum) { |
3ba75830 | 327 | ++nn->payload_misses; |
0b175b18 CL |
328 | trace_nfsd_drc_mismatch(nn, key, rp); |
329 | } | |
ef9b16dc | 330 | |
ed00c2f6 | 331 | return memcmp(&key->c_key, &rp->c_key, sizeof(key->c_key)); |
9dc56143 JL |
332 | } |
333 | ||
a4a3ec32 JL |
334 | /* |
335 | * Search the request hash for an entry that matches the given rqstp. | |
336 | * Must be called with cache_lock held. Returns the found entry or | |
76ecec21 | 337 | * inserts an empty key on failure. |
a4a3ec32 JL |
338 | */ |
339 | static struct svc_cacherep * | |
3ba75830 BF |
340 | nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key, |
341 | struct nfsd_net *nn) | |
a4a3ec32 | 342 | { |
76ecec21 | 343 | struct svc_cacherep *rp, *ret = key; |
736c6625 TM |
344 | struct rb_node **p = &b->rb_head.rb_node, |
345 | *parent = NULL; | |
98d821bd | 346 | unsigned int entries = 0; |
736c6625 | 347 | int cmp; |
a4a3ec32 | 348 | |
736c6625 | 349 | while (*p != NULL) { |
98d821bd | 350 | ++entries; |
736c6625 TM |
351 | parent = *p; |
352 | rp = rb_entry(parent, struct svc_cacherep, c_node); | |
353 | ||
3ba75830 | 354 | cmp = nfsd_cache_key_cmp(key, rp, nn); |
736c6625 TM |
355 | if (cmp < 0) |
356 | p = &parent->rb_left; | |
357 | else if (cmp > 0) | |
358 | p = &parent->rb_right; | |
359 | else { | |
98d821bd | 360 | ret = rp; |
736c6625 | 361 | goto out; |
98d821bd JL |
362 | } |
363 | } | |
736c6625 TM |
364 | rb_link_node(&key->c_node, parent, p); |
365 | rb_insert_color(&key->c_node, &b->rb_head); | |
366 | out: | |
98d821bd | 367 | /* tally hash chain length stats */ |
3ba75830 BF |
368 | if (entries > nn->longest_chain) { |
369 | nn->longest_chain = entries; | |
370 | nn->longest_chain_cachesize = atomic_read(&nn->num_drc_entries); | |
371 | } else if (entries == nn->longest_chain) { | |
98d821bd | 372 | /* prefer to keep the smallest cachesize possible here */ |
3ba75830 BF |
373 | nn->longest_chain_cachesize = min_t(unsigned int, |
374 | nn->longest_chain_cachesize, | |
375 | atomic_read(&nn->num_drc_entries)); | |
a4a3ec32 | 376 | } |
98d821bd | 377 | |
76ecec21 | 378 | lru_put_end(b, ret); |
98d821bd | 379 | return ret; |
a4a3ec32 JL |
380 | } |
381 | ||
0b175b18 CL |
382 | /** |
383 | * nfsd_cache_lookup - Find an entry in the duplicate reply cache | |
384 | * @rqstp: Incoming Call to find | |
385 | * | |
1da177e4 | 386 | * Try to find an entry matching the current call in the cache. When none |
1ac83629 JL |
387 | * is found, we try to grab the oldest expired entry off the LRU list. If |
388 | * a suitable one isn't there, then drop the cache_lock and allocate a | |
389 | * new one, then search again in case one got inserted while this thread | |
390 | * didn't hold the lock. | |
0b175b18 CL |
391 | * |
392 | * Return values: | |
393 | * %RC_DOIT: Process the request normally | |
394 | * %RC_REPLY: Reply from cache | |
395 | * %RC_DROPIT: Do not process the request further | |
1da177e4 | 396 | */ |
0b175b18 | 397 | int nfsd_cache_lookup(struct svc_rqst *rqstp) |
1da177e4 | 398 | { |
3ba75830 | 399 | struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); |
0338dd15 | 400 | struct svc_cacherep *rp, *found; |
c7afef1f | 401 | __be32 xid = rqstp->rq_xid; |
01a7decf | 402 | __wsum csum; |
3ba75830 BF |
403 | u32 hash = nfsd_cache_hash(xid, nn); |
404 | struct nfsd_drc_bucket *b = &nn->drc_hashtbl[hash]; | |
1091006c | 405 | int type = rqstp->rq_cachetype; |
0b9ea37f | 406 | int rtn = RC_DOIT; |
1da177e4 LT |
407 | |
408 | rqstp->rq_cacherep = NULL; | |
13cc8a78 | 409 | if (type == RC_NOCACHE) { |
1da177e4 | 410 | nfsdstats.rcnocache++; |
0b175b18 | 411 | goto out; |
1da177e4 LT |
412 | } |
413 | ||
01a7decf JL |
414 | csum = nfsd_cache_csum(rqstp); |
415 | ||
0b9ea37f JL |
416 | /* |
417 | * Since the common case is a cache miss followed by an insert, | |
a0ef5e19 | 418 | * preallocate an entry. |
0b9ea37f | 419 | */ |
3ba75830 | 420 | rp = nfsd_reply_cache_alloc(rqstp, csum, nn); |
0b175b18 CL |
421 | if (!rp) |
422 | goto out; | |
0338dd15 | 423 | |
76ecec21 | 424 | spin_lock(&b->cache_lock); |
3ba75830 | 425 | found = nfsd_cache_insert(b, rp, nn); |
76ecec21 | 426 | if (found != rp) { |
3ba75830 | 427 | nfsd_reply_cache_free_locked(NULL, rp, nn); |
0338dd15 JL |
428 | rp = found; |
429 | goto found_entry; | |
1da177e4 LT |
430 | } |
431 | ||
0338dd15 | 432 | nfsdstats.rcmisses++; |
1da177e4 LT |
433 | rqstp->rq_cacherep = rp; |
434 | rp->c_state = RC_INPROG; | |
76ecec21 | 435 | |
3ba75830 BF |
436 | atomic_inc(&nn->num_drc_entries); |
437 | nn->drc_mem_usage += sizeof(*rp); | |
76ecec21 TM |
438 | |
439 | /* go ahead and prune the cache */ | |
3ba75830 | 440 | prune_bucket(b, nn); |
0b175b18 CL |
441 | |
442 | out_unlock: | |
89a26b3d | 443 | spin_unlock(&b->cache_lock); |
0b175b18 | 444 | out: |
1da177e4 LT |
445 | return rtn; |
446 | ||
447 | found_entry: | |
448 | /* We found a matching entry which is either in progress or done. */ | |
76ecec21 | 449 | nfsdstats.rchits++; |
1da177e4 | 450 | rtn = RC_DROPIT; |
76ecec21 | 451 | |
7e5d0e0d TM |
452 | /* Request being processed */ |
453 | if (rp->c_state == RC_INPROG) | |
0b175b18 | 454 | goto out_trace; |
1da177e4 LT |
455 | |
456 | /* From the hall of fame of impractical attacks: | |
457 | * Is this a user who tries to snoop on the cache? */ | |
458 | rtn = RC_DOIT; | |
4d152e2c | 459 | if (!test_bit(RQ_SECURE, &rqstp->rq_flags) && rp->c_secure) |
0b175b18 | 460 | goto out_trace; |
1da177e4 LT |
461 | |
462 | /* Compose RPC reply header */ | |
463 | switch (rp->c_type) { | |
464 | case RC_NOCACHE: | |
465 | break; | |
466 | case RC_REPLSTAT: | |
467 | svc_putu32(&rqstp->rq_res.head[0], rp->c_replstat); | |
468 | rtn = RC_REPLY; | |
469 | break; | |
470 | case RC_REPLBUFF: | |
471 | if (!nfsd_cache_append(rqstp, &rp->c_replvec)) | |
0b175b18 | 472 | goto out_unlock; /* should not happen */ |
1da177e4 LT |
473 | rtn = RC_REPLY; |
474 | break; | |
475 | default: | |
c25bf185 | 476 | WARN_ONCE(1, "nfsd: bad repcache type %d\n", rp->c_type); |
1da177e4 LT |
477 | } |
478 | ||
0b175b18 CL |
479 | out_trace: |
480 | trace_nfsd_drc_found(nn, rqstp, rtn); | |
481 | goto out_unlock; | |
1da177e4 LT |
482 | } |
483 | ||
0b175b18 CL |
484 | /** |
485 | * nfsd_cache_update - Update an entry in the duplicate reply cache. | |
486 | * @rqstp: svc_rqst with a finished Reply | |
487 | * @cachetype: which cache to update | |
488 | * @statp: Reply's status code | |
489 | * | |
490 | * This is called from nfsd_dispatch when the procedure has been | |
491 | * executed and the complete reply is in rqstp->rq_res. | |
1da177e4 LT |
492 | * |
493 | * We're copying around data here rather than swapping buffers because | |
494 | * the toplevel loop requires max-sized buffers, which would be a waste | |
495 | * of memory for a cache with a max reply size of 100 bytes (diropokres). | |
496 | * | |
497 | * If we should start to use different types of cache entries tailored | |
498 | * specifically for attrstat and fh's, we may save even more space. | |
499 | * | |
500 | * Also note that a cachetype of RC_NOCACHE can legally be passed when | |
501 | * nfsd failed to encode a reply that otherwise would have been cached. | |
502 | * In this case, nfsd_cache_update is called with statp == NULL. | |
503 | */ | |
0b175b18 | 504 | void nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) |
1da177e4 | 505 | { |
3ba75830 | 506 | struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); |
13cc8a78 | 507 | struct svc_cacherep *rp = rqstp->rq_cacherep; |
1da177e4 | 508 | struct kvec *resv = &rqstp->rq_res.head[0], *cachv; |
bedd4b61 TM |
509 | u32 hash; |
510 | struct nfsd_drc_bucket *b; | |
1da177e4 | 511 | int len; |
6c6910cd | 512 | size_t bufsize = 0; |
1da177e4 | 513 | |
13cc8a78 | 514 | if (!rp) |
1da177e4 LT |
515 | return; |
516 | ||
3ba75830 BF |
517 | hash = nfsd_cache_hash(rp->c_key.k_xid, nn); |
518 | b = &nn->drc_hashtbl[hash]; | |
bedd4b61 | 519 | |
1da177e4 LT |
520 | len = resv->iov_len - ((char*)statp - (char*)resv->iov_base); |
521 | len >>= 2; | |
fca4217c | 522 | |
1da177e4 LT |
523 | /* Don't cache excessive amounts of data and XDR failures */ |
524 | if (!statp || len > (256 >> 2)) { | |
3ba75830 | 525 | nfsd_reply_cache_free(b, rp, nn); |
1da177e4 LT |
526 | return; |
527 | } | |
528 | ||
529 | switch (cachetype) { | |
530 | case RC_REPLSTAT: | |
531 | if (len != 1) | |
532 | printk("nfsd: RC_REPLSTAT/reply len %d!\n",len); | |
533 | rp->c_replstat = *statp; | |
534 | break; | |
535 | case RC_REPLBUFF: | |
536 | cachv = &rp->c_replvec; | |
6c6910cd JL |
537 | bufsize = len << 2; |
538 | cachv->iov_base = kmalloc(bufsize, GFP_KERNEL); | |
1da177e4 | 539 | if (!cachv->iov_base) { |
3ba75830 | 540 | nfsd_reply_cache_free(b, rp, nn); |
1da177e4 LT |
541 | return; |
542 | } | |
6c6910cd JL |
543 | cachv->iov_len = bufsize; |
544 | memcpy(cachv->iov_base, statp, bufsize); | |
1da177e4 | 545 | break; |
2c6b691c | 546 | case RC_NOCACHE: |
3ba75830 | 547 | nfsd_reply_cache_free(b, rp, nn); |
2c6b691c | 548 | return; |
1da177e4 | 549 | } |
89a26b3d | 550 | spin_lock(&b->cache_lock); |
3ba75830 | 551 | nn->drc_mem_usage += bufsize; |
bedd4b61 | 552 | lru_put_end(b, rp); |
4d152e2c | 553 | rp->c_secure = test_bit(RQ_SECURE, &rqstp->rq_flags); |
1da177e4 LT |
554 | rp->c_type = cachetype; |
555 | rp->c_state = RC_DONE; | |
89a26b3d | 556 | spin_unlock(&b->cache_lock); |
1da177e4 LT |
557 | return; |
558 | } | |
559 | ||
560 | /* | |
561 | * Copy cached reply to current reply buffer. Should always fit. | |
562 | * FIXME as reply is in a page, we should just attach the page, and | |
563 | * keep a refcount.... | |
564 | */ | |
565 | static int | |
566 | nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data) | |
567 | { | |
568 | struct kvec *vec = &rqstp->rq_res.head[0]; | |
569 | ||
570 | if (vec->iov_len + data->iov_len > PAGE_SIZE) { | |
5b5e0928 | 571 | printk(KERN_WARNING "nfsd: cached reply too large (%zd).\n", |
1da177e4 LT |
572 | data->iov_len); |
573 | return 0; | |
574 | } | |
575 | memcpy((char*)vec->iov_base + vec->iov_len, data->iov_base, data->iov_len); | |
576 | vec->iov_len += data->iov_len; | |
577 | return 1; | |
578 | } | |
a2f999a3 JL |
579 | |
580 | /* | |
581 | * Note that fields may be added, removed or reordered in the future. Programs | |
582 | * scraping this file for info should test the labels to ensure they're | |
583 | * getting the correct field. | |
584 | */ | |
585 | static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v) | |
586 | { | |
78e70e78 | 587 | struct nfsd_net *nn = m->private; |
3ba75830 BF |
588 | |
589 | seq_printf(m, "max entries: %u\n", nn->max_drc_entries); | |
31e60f52 | 590 | seq_printf(m, "num entries: %u\n", |
3ba75830 BF |
591 | atomic_read(&nn->num_drc_entries)); |
592 | seq_printf(m, "hash buckets: %u\n", 1 << nn->maskbits); | |
593 | seq_printf(m, "mem usage: %u\n", nn->drc_mem_usage); | |
a2f999a3 JL |
594 | seq_printf(m, "cache hits: %u\n", nfsdstats.rchits); |
595 | seq_printf(m, "cache misses: %u\n", nfsdstats.rcmisses); | |
596 | seq_printf(m, "not cached: %u\n", nfsdstats.rcnocache); | |
3ba75830 BF |
597 | seq_printf(m, "payload misses: %u\n", nn->payload_misses); |
598 | seq_printf(m, "longest chain len: %u\n", nn->longest_chain); | |
599 | seq_printf(m, "cachesize at longest: %u\n", nn->longest_chain_cachesize); | |
a2f999a3 JL |
600 | return 0; |
601 | } | |
602 | ||
603 | int nfsd_reply_cache_stats_open(struct inode *inode, struct file *file) | |
604 | { | |
3ba75830 BF |
605 | struct nfsd_net *nn = net_generic(file_inode(file)->i_sb->s_fs_info, |
606 | nfsd_net_id); | |
607 | ||
608 | return single_open(file, nfsd_reply_cache_stats_show, nn); | |
a2f999a3 | 609 | } |