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Commit | Line | Data |
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65294c1f JL |
1 | /* |
2 | * Open file cache. | |
3 | * | |
4 | * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com> | |
5 | */ | |
6 | ||
7 | #include <linux/hash.h> | |
8 | #include <linux/slab.h> | |
65294c1f JL |
9 | #include <linux/file.h> |
10 | #include <linux/sched.h> | |
11 | #include <linux/list_lru.h> | |
12 | #include <linux/fsnotify_backend.h> | |
13 | #include <linux/fsnotify.h> | |
14 | #include <linux/seq_file.h> | |
15 | ||
16 | #include "vfs.h" | |
17 | #include "nfsd.h" | |
18 | #include "nfsfh.h" | |
5e113224 | 19 | #include "netns.h" |
65294c1f JL |
20 | #include "filecache.h" |
21 | #include "trace.h" | |
22 | ||
23 | #define NFSDDBG_FACILITY NFSDDBG_FH | |
24 | ||
25 | /* FIXME: dynamically size this for the machine somehow? */ | |
26 | #define NFSD_FILE_HASH_BITS 12 | |
27 | #define NFSD_FILE_HASH_SIZE (1 << NFSD_FILE_HASH_BITS) | |
28 | #define NFSD_LAUNDRETTE_DELAY (2 * HZ) | |
29 | ||
65294c1f JL |
30 | #define NFSD_FILE_SHUTDOWN (1) |
31 | #define NFSD_FILE_LRU_THRESHOLD (4096UL) | |
32 | #define NFSD_FILE_LRU_LIMIT (NFSD_FILE_LRU_THRESHOLD << 2) | |
33 | ||
34 | /* We only care about NFSD_MAY_READ/WRITE for this cache */ | |
35 | #define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE) | |
36 | ||
37 | struct nfsd_fcache_bucket { | |
38 | struct hlist_head nfb_head; | |
39 | spinlock_t nfb_lock; | |
40 | unsigned int nfb_count; | |
41 | unsigned int nfb_maxcount; | |
42 | }; | |
43 | ||
44 | static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits); | |
45 | ||
9542e6a6 TM |
46 | struct nfsd_fcache_disposal { |
47 | struct list_head list; | |
48 | struct work_struct work; | |
49 | struct net *net; | |
50 | spinlock_t lock; | |
51 | struct list_head freeme; | |
52 | struct rcu_head rcu; | |
53 | }; | |
54 | ||
50d0def9 | 55 | static struct workqueue_struct *nfsd_filecache_wq __read_mostly; |
9542e6a6 | 56 | |
65294c1f JL |
57 | static struct kmem_cache *nfsd_file_slab; |
58 | static struct kmem_cache *nfsd_file_mark_slab; | |
59 | static struct nfsd_fcache_bucket *nfsd_file_hashtbl; | |
60 | static struct list_lru nfsd_file_lru; | |
61 | static long nfsd_file_lru_flags; | |
62 | static struct fsnotify_group *nfsd_file_fsnotify_group; | |
63 | static atomic_long_t nfsd_filecache_count; | |
64 | static struct delayed_work nfsd_filecache_laundrette; | |
9542e6a6 TM |
65 | static DEFINE_SPINLOCK(laundrette_lock); |
66 | static LIST_HEAD(laundrettes); | |
65294c1f | 67 | |
9542e6a6 | 68 | static void nfsd_file_gc(void); |
65294c1f JL |
69 | |
70 | static void | |
9542e6a6 | 71 | nfsd_file_schedule_laundrette(void) |
65294c1f JL |
72 | { |
73 | long count = atomic_long_read(&nfsd_filecache_count); | |
74 | ||
75 | if (count == 0 || test_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags)) | |
76 | return; | |
77 | ||
9542e6a6 TM |
78 | queue_delayed_work(system_wq, &nfsd_filecache_laundrette, |
79 | NFSD_LAUNDRETTE_DELAY); | |
65294c1f JL |
80 | } |
81 | ||
82 | static void | |
83 | nfsd_file_slab_free(struct rcu_head *rcu) | |
84 | { | |
85 | struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu); | |
86 | ||
87 | put_cred(nf->nf_cred); | |
88 | kmem_cache_free(nfsd_file_slab, nf); | |
89 | } | |
90 | ||
91 | static void | |
92 | nfsd_file_mark_free(struct fsnotify_mark *mark) | |
93 | { | |
94 | struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark, | |
95 | nfm_mark); | |
96 | ||
97 | kmem_cache_free(nfsd_file_mark_slab, nfm); | |
98 | } | |
99 | ||
100 | static struct nfsd_file_mark * | |
101 | nfsd_file_mark_get(struct nfsd_file_mark *nfm) | |
102 | { | |
689827cd | 103 | if (!refcount_inc_not_zero(&nfm->nfm_ref)) |
65294c1f JL |
104 | return NULL; |
105 | return nfm; | |
106 | } | |
107 | ||
108 | static void | |
109 | nfsd_file_mark_put(struct nfsd_file_mark *nfm) | |
110 | { | |
689827cd | 111 | if (refcount_dec_and_test(&nfm->nfm_ref)) { |
65294c1f JL |
112 | fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group); |
113 | fsnotify_put_mark(&nfm->nfm_mark); | |
114 | } | |
115 | } | |
116 | ||
117 | static struct nfsd_file_mark * | |
118 | nfsd_file_mark_find_or_create(struct nfsd_file *nf) | |
119 | { | |
120 | int err; | |
121 | struct fsnotify_mark *mark; | |
122 | struct nfsd_file_mark *nfm = NULL, *new; | |
123 | struct inode *inode = nf->nf_inode; | |
124 | ||
125 | do { | |
126 | mutex_lock(&nfsd_file_fsnotify_group->mark_mutex); | |
127 | mark = fsnotify_find_mark(&inode->i_fsnotify_marks, | |
128 | nfsd_file_fsnotify_group); | |
129 | if (mark) { | |
130 | nfm = nfsd_file_mark_get(container_of(mark, | |
131 | struct nfsd_file_mark, | |
132 | nfm_mark)); | |
133 | mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); | |
90d2f1da TM |
134 | if (nfm) { |
135 | fsnotify_put_mark(mark); | |
65294c1f | 136 | break; |
90d2f1da TM |
137 | } |
138 | /* Avoid soft lockup race with nfsd_file_mark_put() */ | |
139 | fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group); | |
140 | fsnotify_put_mark(mark); | |
65294c1f JL |
141 | } else |
142 | mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); | |
143 | ||
144 | /* allocate a new nfm */ | |
145 | new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL); | |
146 | if (!new) | |
147 | return NULL; | |
148 | fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group); | |
149 | new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF; | |
689827cd | 150 | refcount_set(&new->nfm_ref, 1); |
65294c1f JL |
151 | |
152 | err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0); | |
153 | ||
154 | /* | |
155 | * If the add was successful, then return the object. | |
156 | * Otherwise, we need to put the reference we hold on the | |
157 | * nfm_mark. The fsnotify code will take a reference and put | |
158 | * it on failure, so we can't just free it directly. It's also | |
159 | * not safe to call fsnotify_destroy_mark on it as the | |
160 | * mark->group will be NULL. Thus, we can't let the nfm_ref | |
161 | * counter drive the destruction at this point. | |
162 | */ | |
163 | if (likely(!err)) | |
164 | nfm = new; | |
165 | else | |
166 | fsnotify_put_mark(&new->nfm_mark); | |
167 | } while (unlikely(err == -EEXIST)); | |
168 | ||
169 | return nfm; | |
170 | } | |
171 | ||
172 | static struct nfsd_file * | |
5e113224 TM |
173 | nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, |
174 | struct net *net) | |
65294c1f JL |
175 | { |
176 | struct nfsd_file *nf; | |
177 | ||
178 | nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL); | |
179 | if (nf) { | |
180 | INIT_HLIST_NODE(&nf->nf_node); | |
181 | INIT_LIST_HEAD(&nf->nf_lru); | |
182 | nf->nf_file = NULL; | |
183 | nf->nf_cred = get_current_cred(); | |
5e113224 | 184 | nf->nf_net = net; |
65294c1f JL |
185 | nf->nf_flags = 0; |
186 | nf->nf_inode = inode; | |
187 | nf->nf_hashval = hashval; | |
689827cd | 188 | refcount_set(&nf->nf_ref, 1); |
65294c1f JL |
189 | nf->nf_may = may & NFSD_FILE_MAY_MASK; |
190 | if (may & NFSD_MAY_NOT_BREAK_LEASE) { | |
191 | if (may & NFSD_MAY_WRITE) | |
192 | __set_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags); | |
193 | if (may & NFSD_MAY_READ) | |
194 | __set_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags); | |
195 | } | |
196 | nf->nf_mark = NULL; | |
5011af4c | 197 | init_rwsem(&nf->nf_rwsem); |
65294c1f JL |
198 | trace_nfsd_file_alloc(nf); |
199 | } | |
200 | return nf; | |
201 | } | |
202 | ||
203 | static bool | |
204 | nfsd_file_free(struct nfsd_file *nf) | |
205 | { | |
206 | bool flush = false; | |
207 | ||
208 | trace_nfsd_file_put_final(nf); | |
209 | if (nf->nf_mark) | |
210 | nfsd_file_mark_put(nf->nf_mark); | |
211 | if (nf->nf_file) { | |
212 | get_file(nf->nf_file); | |
213 | filp_close(nf->nf_file, NULL); | |
214 | fput(nf->nf_file); | |
215 | flush = true; | |
216 | } | |
217 | call_rcu(&nf->nf_rcu, nfsd_file_slab_free); | |
218 | return flush; | |
219 | } | |
220 | ||
055b24a8 TM |
221 | static bool |
222 | nfsd_file_check_writeback(struct nfsd_file *nf) | |
223 | { | |
224 | struct file *file = nf->nf_file; | |
225 | struct address_space *mapping; | |
226 | ||
227 | if (!file || !(file->f_mode & FMODE_WRITE)) | |
228 | return false; | |
229 | mapping = file->f_mapping; | |
230 | return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) || | |
231 | mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK); | |
232 | } | |
233 | ||
234 | static int | |
235 | nfsd_file_check_write_error(struct nfsd_file *nf) | |
236 | { | |
237 | struct file *file = nf->nf_file; | |
238 | ||
239 | if (!file || !(file->f_mode & FMODE_WRITE)) | |
240 | return 0; | |
241 | return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err)); | |
242 | } | |
243 | ||
65294c1f JL |
244 | static void |
245 | nfsd_file_do_unhash(struct nfsd_file *nf) | |
246 | { | |
247 | lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); | |
248 | ||
249 | trace_nfsd_file_unhash(nf); | |
250 | ||
055b24a8 TM |
251 | if (nfsd_file_check_write_error(nf)) |
252 | nfsd_reset_boot_verifier(net_generic(nf->nf_net, nfsd_net_id)); | |
65294c1f JL |
253 | --nfsd_file_hashtbl[nf->nf_hashval].nfb_count; |
254 | hlist_del_rcu(&nf->nf_node); | |
65294c1f JL |
255 | atomic_long_dec(&nfsd_filecache_count); |
256 | } | |
257 | ||
258 | static bool | |
259 | nfsd_file_unhash(struct nfsd_file *nf) | |
260 | { | |
261 | if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { | |
262 | nfsd_file_do_unhash(nf); | |
36ebbdb9 TM |
263 | if (!list_empty(&nf->nf_lru)) |
264 | list_lru_del(&nfsd_file_lru, &nf->nf_lru); | |
65294c1f JL |
265 | return true; |
266 | } | |
267 | return false; | |
268 | } | |
269 | ||
270 | /* | |
271 | * Return true if the file was unhashed. | |
272 | */ | |
273 | static bool | |
274 | nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *dispose) | |
275 | { | |
276 | lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); | |
277 | ||
278 | trace_nfsd_file_unhash_and_release_locked(nf); | |
279 | if (!nfsd_file_unhash(nf)) | |
280 | return false; | |
281 | /* keep final reference for nfsd_file_lru_dispose */ | |
689827cd | 282 | if (refcount_dec_not_one(&nf->nf_ref)) |
65294c1f JL |
283 | return true; |
284 | ||
285 | list_add(&nf->nf_lru, dispose); | |
286 | return true; | |
287 | } | |
288 | ||
b6669305 | 289 | static void |
65294c1f JL |
290 | nfsd_file_put_noref(struct nfsd_file *nf) |
291 | { | |
65294c1f JL |
292 | trace_nfsd_file_put(nf); |
293 | ||
689827cd | 294 | if (refcount_dec_and_test(&nf->nf_ref)) { |
65294c1f JL |
295 | WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags)); |
296 | nfsd_file_free(nf); | |
297 | } | |
65294c1f JL |
298 | } |
299 | ||
300 | void | |
301 | nfsd_file_put(struct nfsd_file *nf) | |
302 | { | |
b6669305 | 303 | bool is_hashed; |
65294c1f JL |
304 | |
305 | set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags); | |
689827cd | 306 | if (refcount_read(&nf->nf_ref) > 2 || !nf->nf_file) { |
b6669305 TM |
307 | nfsd_file_put_noref(nf); |
308 | return; | |
309 | } | |
310 | ||
311 | filemap_flush(nf->nf_file->f_mapping); | |
312 | is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0; | |
313 | nfsd_file_put_noref(nf); | |
314 | if (is_hashed) | |
9542e6a6 TM |
315 | nfsd_file_schedule_laundrette(); |
316 | if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT) | |
317 | nfsd_file_gc(); | |
65294c1f JL |
318 | } |
319 | ||
320 | struct nfsd_file * | |
321 | nfsd_file_get(struct nfsd_file *nf) | |
322 | { | |
689827cd | 323 | if (likely(refcount_inc_not_zero(&nf->nf_ref))) |
65294c1f JL |
324 | return nf; |
325 | return NULL; | |
326 | } | |
327 | ||
328 | static void | |
329 | nfsd_file_dispose_list(struct list_head *dispose) | |
330 | { | |
331 | struct nfsd_file *nf; | |
332 | ||
333 | while(!list_empty(dispose)) { | |
334 | nf = list_first_entry(dispose, struct nfsd_file, nf_lru); | |
335 | list_del(&nf->nf_lru); | |
336 | nfsd_file_put_noref(nf); | |
337 | } | |
338 | } | |
339 | ||
340 | static void | |
341 | nfsd_file_dispose_list_sync(struct list_head *dispose) | |
342 | { | |
343 | bool flush = false; | |
344 | struct nfsd_file *nf; | |
345 | ||
346 | while(!list_empty(dispose)) { | |
347 | nf = list_first_entry(dispose, struct nfsd_file, nf_lru); | |
348 | list_del(&nf->nf_lru); | |
689827cd | 349 | if (!refcount_dec_and_test(&nf->nf_ref)) |
65294c1f JL |
350 | continue; |
351 | if (nfsd_file_free(nf)) | |
352 | flush = true; | |
353 | } | |
354 | if (flush) | |
355 | flush_delayed_fput(); | |
356 | } | |
357 | ||
9542e6a6 TM |
358 | static void |
359 | nfsd_file_list_remove_disposal(struct list_head *dst, | |
360 | struct nfsd_fcache_disposal *l) | |
361 | { | |
362 | spin_lock(&l->lock); | |
363 | list_splice_init(&l->freeme, dst); | |
364 | spin_unlock(&l->lock); | |
365 | } | |
366 | ||
367 | static void | |
368 | nfsd_file_list_add_disposal(struct list_head *files, struct net *net) | |
369 | { | |
370 | struct nfsd_fcache_disposal *l; | |
371 | ||
372 | rcu_read_lock(); | |
373 | list_for_each_entry_rcu(l, &laundrettes, list) { | |
374 | if (l->net == net) { | |
375 | spin_lock(&l->lock); | |
376 | list_splice_tail_init(files, &l->freeme); | |
377 | spin_unlock(&l->lock); | |
378 | queue_work(nfsd_filecache_wq, &l->work); | |
379 | break; | |
380 | } | |
381 | } | |
382 | rcu_read_unlock(); | |
383 | } | |
384 | ||
385 | static void | |
386 | nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src, | |
387 | struct net *net) | |
388 | { | |
389 | struct nfsd_file *nf, *tmp; | |
390 | ||
391 | list_for_each_entry_safe(nf, tmp, src, nf_lru) { | |
392 | if (nf->nf_net == net) | |
393 | list_move_tail(&nf->nf_lru, dst); | |
394 | } | |
395 | } | |
396 | ||
397 | static void | |
398 | nfsd_file_dispose_list_delayed(struct list_head *dispose) | |
399 | { | |
400 | LIST_HEAD(list); | |
401 | struct nfsd_file *nf; | |
402 | ||
403 | while(!list_empty(dispose)) { | |
404 | nf = list_first_entry(dispose, struct nfsd_file, nf_lru); | |
405 | nfsd_file_list_add_pernet(&list, dispose, nf->nf_net); | |
406 | nfsd_file_list_add_disposal(&list, nf->nf_net); | |
407 | } | |
408 | } | |
409 | ||
65294c1f JL |
410 | /* |
411 | * Note this can deadlock with nfsd_file_cache_purge. | |
412 | */ | |
413 | static enum lru_status | |
414 | nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, | |
415 | spinlock_t *lock, void *arg) | |
416 | __releases(lock) | |
417 | __acquires(lock) | |
418 | { | |
419 | struct list_head *head = arg; | |
420 | struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru); | |
421 | ||
422 | /* | |
423 | * Do a lockless refcount check. The hashtable holds one reference, so | |
424 | * we look to see if anything else has a reference, or if any have | |
425 | * been put since the shrinker last ran. Those don't get unhashed and | |
426 | * released. | |
427 | * | |
428 | * Note that in the put path, we set the flag and then decrement the | |
429 | * counter. Here we check the counter and then test and clear the flag. | |
430 | * That order is deliberate to ensure that we can do this locklessly. | |
431 | */ | |
689827cd | 432 | if (refcount_read(&nf->nf_ref) > 1) |
65294c1f | 433 | goto out_skip; |
055b24a8 TM |
434 | |
435 | /* | |
436 | * Don't throw out files that are still undergoing I/O or | |
437 | * that have uncleared errors pending. | |
438 | */ | |
439 | if (nfsd_file_check_writeback(nf)) | |
440 | goto out_skip; | |
441 | ||
65294c1f | 442 | if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) |
bd6e1cec | 443 | goto out_skip; |
65294c1f JL |
444 | |
445 | if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) | |
446 | goto out_skip; | |
447 | ||
448 | list_lru_isolate_move(lru, &nf->nf_lru, head); | |
449 | return LRU_REMOVED; | |
65294c1f JL |
450 | out_skip: |
451 | return LRU_SKIP; | |
452 | } | |
453 | ||
9542e6a6 TM |
454 | static unsigned long |
455 | nfsd_file_lru_walk_list(struct shrink_control *sc) | |
65294c1f | 456 | { |
9542e6a6 | 457 | LIST_HEAD(head); |
36ebbdb9 | 458 | struct nfsd_file *nf; |
9542e6a6 | 459 | unsigned long ret; |
36ebbdb9 | 460 | |
9542e6a6 TM |
461 | if (sc) |
462 | ret = list_lru_shrink_walk(&nfsd_file_lru, sc, | |
463 | nfsd_file_lru_cb, &head); | |
464 | else | |
465 | ret = list_lru_walk(&nfsd_file_lru, | |
466 | nfsd_file_lru_cb, | |
467 | &head, LONG_MAX); | |
468 | list_for_each_entry(nf, &head, nf_lru) { | |
65294c1f JL |
469 | spin_lock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); |
470 | nfsd_file_do_unhash(nf); | |
471 | spin_unlock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); | |
65294c1f | 472 | } |
9542e6a6 TM |
473 | nfsd_file_dispose_list_delayed(&head); |
474 | return ret; | |
475 | } | |
476 | ||
477 | static void | |
478 | nfsd_file_gc(void) | |
479 | { | |
480 | nfsd_file_lru_walk_list(NULL); | |
481 | } | |
482 | ||
483 | static void | |
484 | nfsd_file_gc_worker(struct work_struct *work) | |
485 | { | |
486 | nfsd_file_gc(); | |
487 | nfsd_file_schedule_laundrette(); | |
65294c1f JL |
488 | } |
489 | ||
490 | static unsigned long | |
491 | nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc) | |
492 | { | |
493 | return list_lru_count(&nfsd_file_lru); | |
494 | } | |
495 | ||
496 | static unsigned long | |
497 | nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc) | |
498 | { | |
9542e6a6 | 499 | return nfsd_file_lru_walk_list(sc); |
65294c1f JL |
500 | } |
501 | ||
502 | static struct shrinker nfsd_file_shrinker = { | |
503 | .scan_objects = nfsd_file_lru_scan, | |
504 | .count_objects = nfsd_file_lru_count, | |
505 | .seeks = 1, | |
506 | }; | |
507 | ||
508 | static void | |
509 | __nfsd_file_close_inode(struct inode *inode, unsigned int hashval, | |
510 | struct list_head *dispose) | |
511 | { | |
512 | struct nfsd_file *nf; | |
513 | struct hlist_node *tmp; | |
514 | ||
515 | spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
516 | hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) { | |
517 | if (inode == nf->nf_inode) | |
518 | nfsd_file_unhash_and_release_locked(nf, dispose); | |
519 | } | |
520 | spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
521 | } | |
522 | ||
523 | /** | |
524 | * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file | |
525 | * @inode: inode of the file to attempt to remove | |
526 | * | |
527 | * Walk the whole hash bucket, looking for any files that correspond to "inode". | |
528 | * If any do, then unhash them and put the hashtable reference to them and | |
529 | * destroy any that had their last reference put. Also ensure that any of the | |
530 | * fputs also have their final __fput done as well. | |
531 | */ | |
532 | void | |
533 | nfsd_file_close_inode_sync(struct inode *inode) | |
534 | { | |
535 | unsigned int hashval = (unsigned int)hash_long(inode->i_ino, | |
536 | NFSD_FILE_HASH_BITS); | |
537 | LIST_HEAD(dispose); | |
538 | ||
539 | __nfsd_file_close_inode(inode, hashval, &dispose); | |
540 | trace_nfsd_file_close_inode_sync(inode, hashval, !list_empty(&dispose)); | |
541 | nfsd_file_dispose_list_sync(&dispose); | |
542 | } | |
543 | ||
544 | /** | |
545 | * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file | |
546 | * @inode: inode of the file to attempt to remove | |
547 | * | |
548 | * Walk the whole hash bucket, looking for any files that correspond to "inode". | |
549 | * If any do, then unhash them and put the hashtable reference to them and | |
550 | * destroy any that had their last reference put. | |
551 | */ | |
552 | static void | |
553 | nfsd_file_close_inode(struct inode *inode) | |
554 | { | |
555 | unsigned int hashval = (unsigned int)hash_long(inode->i_ino, | |
556 | NFSD_FILE_HASH_BITS); | |
557 | LIST_HEAD(dispose); | |
558 | ||
559 | __nfsd_file_close_inode(inode, hashval, &dispose); | |
560 | trace_nfsd_file_close_inode(inode, hashval, !list_empty(&dispose)); | |
9542e6a6 | 561 | nfsd_file_dispose_list_delayed(&dispose); |
65294c1f JL |
562 | } |
563 | ||
564 | /** | |
565 | * nfsd_file_delayed_close - close unused nfsd_files | |
566 | * @work: dummy | |
567 | * | |
568 | * Walk the LRU list and close any entries that have not been used since | |
569 | * the last scan. | |
570 | * | |
571 | * Note this can deadlock with nfsd_file_cache_purge. | |
572 | */ | |
573 | static void | |
574 | nfsd_file_delayed_close(struct work_struct *work) | |
575 | { | |
576 | LIST_HEAD(head); | |
9542e6a6 TM |
577 | struct nfsd_fcache_disposal *l = container_of(work, |
578 | struct nfsd_fcache_disposal, work); | |
65294c1f | 579 | |
9542e6a6 TM |
580 | nfsd_file_list_remove_disposal(&head, l); |
581 | nfsd_file_dispose_list(&head); | |
65294c1f JL |
582 | } |
583 | ||
584 | static int | |
585 | nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg, | |
586 | void *data) | |
587 | { | |
588 | struct file_lock *fl = data; | |
589 | ||
590 | /* Only close files for F_SETLEASE leases */ | |
591 | if (fl->fl_flags & FL_LEASE) | |
592 | nfsd_file_close_inode_sync(file_inode(fl->fl_file)); | |
593 | return 0; | |
594 | } | |
595 | ||
596 | static struct notifier_block nfsd_file_lease_notifier = { | |
597 | .notifier_call = nfsd_file_lease_notifier_call, | |
598 | }; | |
599 | ||
600 | static int | |
b9a1b977 AG |
601 | nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask, |
602 | struct inode *inode, struct inode *dir, | |
950cc0d2 | 603 | const struct qstr *name, u32 cookie) |
65294c1f JL |
604 | { |
605 | trace_nfsd_file_fsnotify_handle_event(inode, mask); | |
606 | ||
607 | /* Should be no marks on non-regular files */ | |
608 | if (!S_ISREG(inode->i_mode)) { | |
609 | WARN_ON_ONCE(1); | |
610 | return 0; | |
611 | } | |
612 | ||
613 | /* don't close files if this was not the last link */ | |
614 | if (mask & FS_ATTRIB) { | |
615 | if (inode->i_nlink) | |
616 | return 0; | |
617 | } | |
618 | ||
619 | nfsd_file_close_inode(inode); | |
620 | return 0; | |
621 | } | |
622 | ||
623 | ||
624 | static const struct fsnotify_ops nfsd_file_fsnotify_ops = { | |
b9a1b977 | 625 | .handle_inode_event = nfsd_file_fsnotify_handle_event, |
65294c1f JL |
626 | .free_mark = nfsd_file_mark_free, |
627 | }; | |
628 | ||
629 | int | |
630 | nfsd_file_cache_init(void) | |
631 | { | |
632 | int ret = -ENOMEM; | |
633 | unsigned int i; | |
634 | ||
635 | clear_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags); | |
636 | ||
637 | if (nfsd_file_hashtbl) | |
638 | return 0; | |
639 | ||
9542e6a6 TM |
640 | nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0); |
641 | if (!nfsd_filecache_wq) | |
642 | goto out; | |
643 | ||
65294c1f JL |
644 | nfsd_file_hashtbl = kcalloc(NFSD_FILE_HASH_SIZE, |
645 | sizeof(*nfsd_file_hashtbl), GFP_KERNEL); | |
646 | if (!nfsd_file_hashtbl) { | |
647 | pr_err("nfsd: unable to allocate nfsd_file_hashtbl\n"); | |
648 | goto out_err; | |
649 | } | |
650 | ||
651 | nfsd_file_slab = kmem_cache_create("nfsd_file", | |
652 | sizeof(struct nfsd_file), 0, 0, NULL); | |
653 | if (!nfsd_file_slab) { | |
654 | pr_err("nfsd: unable to create nfsd_file_slab\n"); | |
655 | goto out_err; | |
656 | } | |
657 | ||
658 | nfsd_file_mark_slab = kmem_cache_create("nfsd_file_mark", | |
659 | sizeof(struct nfsd_file_mark), 0, 0, NULL); | |
660 | if (!nfsd_file_mark_slab) { | |
661 | pr_err("nfsd: unable to create nfsd_file_mark_slab\n"); | |
662 | goto out_err; | |
663 | } | |
664 | ||
665 | ||
666 | ret = list_lru_init(&nfsd_file_lru); | |
667 | if (ret) { | |
668 | pr_err("nfsd: failed to init nfsd_file_lru: %d\n", ret); | |
669 | goto out_err; | |
670 | } | |
671 | ||
672 | ret = register_shrinker(&nfsd_file_shrinker); | |
673 | if (ret) { | |
674 | pr_err("nfsd: failed to register nfsd_file_shrinker: %d\n", ret); | |
675 | goto out_lru; | |
676 | } | |
677 | ||
678 | ret = lease_register_notifier(&nfsd_file_lease_notifier); | |
679 | if (ret) { | |
680 | pr_err("nfsd: unable to register lease notifier: %d\n", ret); | |
681 | goto out_shrinker; | |
682 | } | |
683 | ||
684 | nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops); | |
685 | if (IS_ERR(nfsd_file_fsnotify_group)) { | |
686 | pr_err("nfsd: unable to create fsnotify group: %ld\n", | |
687 | PTR_ERR(nfsd_file_fsnotify_group)); | |
231307df | 688 | ret = PTR_ERR(nfsd_file_fsnotify_group); |
65294c1f JL |
689 | nfsd_file_fsnotify_group = NULL; |
690 | goto out_notifier; | |
691 | } | |
692 | ||
693 | for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { | |
694 | INIT_HLIST_HEAD(&nfsd_file_hashtbl[i].nfb_head); | |
695 | spin_lock_init(&nfsd_file_hashtbl[i].nfb_lock); | |
696 | } | |
697 | ||
9542e6a6 | 698 | INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker); |
65294c1f JL |
699 | out: |
700 | return ret; | |
701 | out_notifier: | |
702 | lease_unregister_notifier(&nfsd_file_lease_notifier); | |
703 | out_shrinker: | |
704 | unregister_shrinker(&nfsd_file_shrinker); | |
705 | out_lru: | |
706 | list_lru_destroy(&nfsd_file_lru); | |
707 | out_err: | |
708 | kmem_cache_destroy(nfsd_file_slab); | |
709 | nfsd_file_slab = NULL; | |
710 | kmem_cache_destroy(nfsd_file_mark_slab); | |
711 | nfsd_file_mark_slab = NULL; | |
712 | kfree(nfsd_file_hashtbl); | |
713 | nfsd_file_hashtbl = NULL; | |
9542e6a6 TM |
714 | destroy_workqueue(nfsd_filecache_wq); |
715 | nfsd_filecache_wq = NULL; | |
65294c1f JL |
716 | goto out; |
717 | } | |
718 | ||
719 | /* | |
720 | * Note this can deadlock with nfsd_file_lru_cb. | |
721 | */ | |
722 | void | |
5e113224 | 723 | nfsd_file_cache_purge(struct net *net) |
65294c1f JL |
724 | { |
725 | unsigned int i; | |
726 | struct nfsd_file *nf; | |
5e113224 | 727 | struct hlist_node *next; |
65294c1f JL |
728 | LIST_HEAD(dispose); |
729 | bool del; | |
730 | ||
731 | if (!nfsd_file_hashtbl) | |
732 | return; | |
733 | ||
734 | for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { | |
5e113224 TM |
735 | struct nfsd_fcache_bucket *nfb = &nfsd_file_hashtbl[i]; |
736 | ||
737 | spin_lock(&nfb->nfb_lock); | |
738 | hlist_for_each_entry_safe(nf, next, &nfb->nfb_head, nf_node) { | |
739 | if (net && nf->nf_net != net) | |
740 | continue; | |
65294c1f JL |
741 | del = nfsd_file_unhash_and_release_locked(nf, &dispose); |
742 | ||
743 | /* | |
744 | * Deadlock detected! Something marked this entry as | |
745 | * unhased, but hasn't removed it from the hash list. | |
746 | */ | |
747 | WARN_ON_ONCE(!del); | |
748 | } | |
5e113224 | 749 | spin_unlock(&nfb->nfb_lock); |
65294c1f JL |
750 | nfsd_file_dispose_list(&dispose); |
751 | } | |
752 | } | |
753 | ||
9542e6a6 TM |
754 | static struct nfsd_fcache_disposal * |
755 | nfsd_alloc_fcache_disposal(struct net *net) | |
756 | { | |
757 | struct nfsd_fcache_disposal *l; | |
758 | ||
759 | l = kmalloc(sizeof(*l), GFP_KERNEL); | |
760 | if (!l) | |
761 | return NULL; | |
762 | INIT_WORK(&l->work, nfsd_file_delayed_close); | |
763 | l->net = net; | |
764 | spin_lock_init(&l->lock); | |
765 | INIT_LIST_HEAD(&l->freeme); | |
766 | return l; | |
767 | } | |
768 | ||
769 | static void | |
770 | nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) | |
771 | { | |
772 | rcu_assign_pointer(l->net, NULL); | |
773 | cancel_work_sync(&l->work); | |
774 | nfsd_file_dispose_list(&l->freeme); | |
775 | kfree_rcu(l, rcu); | |
776 | } | |
777 | ||
778 | static void | |
779 | nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l) | |
780 | { | |
781 | spin_lock(&laundrette_lock); | |
782 | list_add_tail_rcu(&l->list, &laundrettes); | |
783 | spin_unlock(&laundrette_lock); | |
784 | } | |
785 | ||
786 | static void | |
787 | nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l) | |
788 | { | |
789 | spin_lock(&laundrette_lock); | |
790 | list_del_rcu(&l->list); | |
791 | spin_unlock(&laundrette_lock); | |
792 | } | |
793 | ||
794 | static int | |
795 | nfsd_alloc_fcache_disposal_net(struct net *net) | |
796 | { | |
797 | struct nfsd_fcache_disposal *l; | |
798 | ||
799 | l = nfsd_alloc_fcache_disposal(net); | |
800 | if (!l) | |
801 | return -ENOMEM; | |
802 | nfsd_add_fcache_disposal(l); | |
803 | return 0; | |
804 | } | |
805 | ||
806 | static void | |
807 | nfsd_free_fcache_disposal_net(struct net *net) | |
808 | { | |
809 | struct nfsd_fcache_disposal *l; | |
810 | ||
811 | rcu_read_lock(); | |
812 | list_for_each_entry_rcu(l, &laundrettes, list) { | |
813 | if (l->net != net) | |
814 | continue; | |
815 | nfsd_del_fcache_disposal(l); | |
816 | rcu_read_unlock(); | |
817 | nfsd_free_fcache_disposal(l); | |
818 | return; | |
819 | } | |
820 | rcu_read_unlock(); | |
821 | } | |
822 | ||
823 | int | |
824 | nfsd_file_cache_start_net(struct net *net) | |
825 | { | |
826 | return nfsd_alloc_fcache_disposal_net(net); | |
827 | } | |
828 | ||
829 | void | |
830 | nfsd_file_cache_shutdown_net(struct net *net) | |
831 | { | |
832 | nfsd_file_cache_purge(net); | |
833 | nfsd_free_fcache_disposal_net(net); | |
834 | } | |
835 | ||
65294c1f JL |
836 | void |
837 | nfsd_file_cache_shutdown(void) | |
838 | { | |
65294c1f JL |
839 | set_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags); |
840 | ||
841 | lease_unregister_notifier(&nfsd_file_lease_notifier); | |
842 | unregister_shrinker(&nfsd_file_shrinker); | |
843 | /* | |
844 | * make sure all callers of nfsd_file_lru_cb are done before | |
845 | * calling nfsd_file_cache_purge | |
846 | */ | |
847 | cancel_delayed_work_sync(&nfsd_filecache_laundrette); | |
5e113224 | 848 | nfsd_file_cache_purge(NULL); |
65294c1f JL |
849 | list_lru_destroy(&nfsd_file_lru); |
850 | rcu_barrier(); | |
851 | fsnotify_put_group(nfsd_file_fsnotify_group); | |
852 | nfsd_file_fsnotify_group = NULL; | |
853 | kmem_cache_destroy(nfsd_file_slab); | |
854 | nfsd_file_slab = NULL; | |
855 | fsnotify_wait_marks_destroyed(); | |
856 | kmem_cache_destroy(nfsd_file_mark_slab); | |
857 | nfsd_file_mark_slab = NULL; | |
858 | kfree(nfsd_file_hashtbl); | |
859 | nfsd_file_hashtbl = NULL; | |
9542e6a6 TM |
860 | destroy_workqueue(nfsd_filecache_wq); |
861 | nfsd_filecache_wq = NULL; | |
65294c1f JL |
862 | } |
863 | ||
864 | static bool | |
865 | nfsd_match_cred(const struct cred *c1, const struct cred *c2) | |
866 | { | |
867 | int i; | |
868 | ||
869 | if (!uid_eq(c1->fsuid, c2->fsuid)) | |
870 | return false; | |
871 | if (!gid_eq(c1->fsgid, c2->fsgid)) | |
872 | return false; | |
873 | if (c1->group_info == NULL || c2->group_info == NULL) | |
874 | return c1->group_info == c2->group_info; | |
875 | if (c1->group_info->ngroups != c2->group_info->ngroups) | |
876 | return false; | |
877 | for (i = 0; i < c1->group_info->ngroups; i++) { | |
878 | if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i])) | |
879 | return false; | |
880 | } | |
881 | return true; | |
882 | } | |
883 | ||
884 | static struct nfsd_file * | |
885 | nfsd_file_find_locked(struct inode *inode, unsigned int may_flags, | |
5e113224 | 886 | unsigned int hashval, struct net *net) |
65294c1f JL |
887 | { |
888 | struct nfsd_file *nf; | |
889 | unsigned char need = may_flags & NFSD_FILE_MAY_MASK; | |
890 | ||
891 | hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, | |
057a2274 | 892 | nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) { |
ae3c57b5 | 893 | if (nf->nf_may != need) |
65294c1f JL |
894 | continue; |
895 | if (nf->nf_inode != inode) | |
896 | continue; | |
5e113224 TM |
897 | if (nf->nf_net != net) |
898 | continue; | |
65294c1f JL |
899 | if (!nfsd_match_cred(nf->nf_cred, current_cred())) |
900 | continue; | |
901 | if (nfsd_file_get(nf) != NULL) | |
902 | return nf; | |
903 | } | |
904 | return NULL; | |
905 | } | |
906 | ||
907 | /** | |
908 | * nfsd_file_is_cached - are there any cached open files for this fh? | |
909 | * @inode: inode of the file to check | |
910 | * | |
911 | * Scan the hashtable for open files that match this fh. Returns true if there | |
912 | * are any, and false if not. | |
913 | */ | |
914 | bool | |
915 | nfsd_file_is_cached(struct inode *inode) | |
916 | { | |
917 | bool ret = false; | |
918 | struct nfsd_file *nf; | |
919 | unsigned int hashval; | |
920 | ||
921 | hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS); | |
922 | ||
923 | rcu_read_lock(); | |
924 | hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, | |
925 | nf_node) { | |
926 | if (inode == nf->nf_inode) { | |
927 | ret = true; | |
928 | break; | |
929 | } | |
930 | } | |
931 | rcu_read_unlock(); | |
932 | trace_nfsd_file_is_cached(inode, hashval, (int)ret); | |
933 | return ret; | |
934 | } | |
935 | ||
936 | __be32 | |
937 | nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, | |
938 | unsigned int may_flags, struct nfsd_file **pnf) | |
939 | { | |
940 | __be32 status; | |
5e113224 | 941 | struct net *net = SVC_NET(rqstp); |
65294c1f JL |
942 | struct nfsd_file *nf, *new; |
943 | struct inode *inode; | |
944 | unsigned int hashval; | |
28c7d86b | 945 | bool retry = true; |
65294c1f JL |
946 | |
947 | /* FIXME: skip this if fh_dentry is already set? */ | |
948 | status = fh_verify(rqstp, fhp, S_IFREG, | |
949 | may_flags|NFSD_MAY_OWNER_OVERRIDE); | |
950 | if (status != nfs_ok) | |
951 | return status; | |
952 | ||
953 | inode = d_inode(fhp->fh_dentry); | |
954 | hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS); | |
955 | retry: | |
956 | rcu_read_lock(); | |
5e113224 | 957 | nf = nfsd_file_find_locked(inode, may_flags, hashval, net); |
65294c1f JL |
958 | rcu_read_unlock(); |
959 | if (nf) | |
960 | goto wait_for_construction; | |
961 | ||
5e113224 | 962 | new = nfsd_file_alloc(inode, may_flags, hashval, net); |
65294c1f JL |
963 | if (!new) { |
964 | trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, | |
965 | NULL, nfserr_jukebox); | |
966 | return nfserr_jukebox; | |
967 | } | |
968 | ||
969 | spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
5e113224 | 970 | nf = nfsd_file_find_locked(inode, may_flags, hashval, net); |
65294c1f JL |
971 | if (nf == NULL) |
972 | goto open_file; | |
973 | spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
974 | nfsd_file_slab_free(&new->nf_rcu); | |
975 | ||
976 | wait_for_construction: | |
977 | wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE); | |
978 | ||
979 | /* Did construction of this file fail? */ | |
980 | if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { | |
28c7d86b TM |
981 | if (!retry) { |
982 | status = nfserr_jukebox; | |
983 | goto out; | |
984 | } | |
985 | retry = false; | |
65294c1f JL |
986 | nfsd_file_put_noref(nf); |
987 | goto retry; | |
988 | } | |
989 | ||
990 | this_cpu_inc(nfsd_file_cache_hits); | |
991 | ||
992 | if (!(may_flags & NFSD_MAY_NOT_BREAK_LEASE)) { | |
993 | bool write = (may_flags & NFSD_MAY_WRITE); | |
994 | ||
995 | if (test_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags) || | |
996 | (test_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags) && write)) { | |
997 | status = nfserrno(nfsd_open_break_lease( | |
998 | file_inode(nf->nf_file), may_flags)); | |
999 | if (status == nfs_ok) { | |
1000 | clear_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags); | |
1001 | if (write) | |
1002 | clear_bit(NFSD_FILE_BREAK_WRITE, | |
1003 | &nf->nf_flags); | |
1004 | } | |
1005 | } | |
1006 | } | |
1007 | out: | |
1008 | if (status == nfs_ok) { | |
1009 | *pnf = nf; | |
1010 | } else { | |
1011 | nfsd_file_put(nf); | |
1012 | nf = NULL; | |
1013 | } | |
1014 | ||
1015 | trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, nf, status); | |
1016 | return status; | |
1017 | open_file: | |
1018 | nf = new; | |
1019 | /* Take reference for the hashtable */ | |
689827cd | 1020 | refcount_inc(&nf->nf_ref); |
65294c1f JL |
1021 | __set_bit(NFSD_FILE_HASHED, &nf->nf_flags); |
1022 | __set_bit(NFSD_FILE_PENDING, &nf->nf_flags); | |
1023 | list_lru_add(&nfsd_file_lru, &nf->nf_lru); | |
1024 | hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head); | |
1025 | ++nfsd_file_hashtbl[hashval].nfb_count; | |
1026 | nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount, | |
1027 | nfsd_file_hashtbl[hashval].nfb_count); | |
1028 | spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
9542e6a6 TM |
1029 | if (atomic_long_inc_return(&nfsd_filecache_count) >= NFSD_FILE_LRU_THRESHOLD) |
1030 | nfsd_file_gc(); | |
65294c1f JL |
1031 | |
1032 | nf->nf_mark = nfsd_file_mark_find_or_create(nf); | |
1033 | if (nf->nf_mark) | |
1034 | status = nfsd_open_verified(rqstp, fhp, S_IFREG, | |
1035 | may_flags, &nf->nf_file); | |
1036 | else | |
1037 | status = nfserr_jukebox; | |
1038 | /* | |
1039 | * If construction failed, or we raced with a call to unlink() | |
1040 | * then unhash. | |
1041 | */ | |
1042 | if (status != nfs_ok || inode->i_nlink == 0) { | |
1043 | bool do_free; | |
1044 | spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
1045 | do_free = nfsd_file_unhash(nf); | |
1046 | spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); | |
1047 | if (do_free) | |
1048 | nfsd_file_put_noref(nf); | |
1049 | } | |
1050 | clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags); | |
1051 | smp_mb__after_atomic(); | |
1052 | wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING); | |
1053 | goto out; | |
1054 | } | |
1055 | ||
1056 | /* | |
1057 | * Note that fields may be added, removed or reordered in the future. Programs | |
1058 | * scraping this file for info should test the labels to ensure they're | |
1059 | * getting the correct field. | |
1060 | */ | |
1061 | static int nfsd_file_cache_stats_show(struct seq_file *m, void *v) | |
1062 | { | |
1063 | unsigned int i, count = 0, longest = 0; | |
1064 | unsigned long hits = 0; | |
1065 | ||
1066 | /* | |
1067 | * No need for spinlocks here since we're not terribly interested in | |
1068 | * accuracy. We do take the nfsd_mutex simply to ensure that we | |
1069 | * don't end up racing with server shutdown | |
1070 | */ | |
1071 | mutex_lock(&nfsd_mutex); | |
1072 | if (nfsd_file_hashtbl) { | |
1073 | for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { | |
1074 | count += nfsd_file_hashtbl[i].nfb_count; | |
1075 | longest = max(longest, nfsd_file_hashtbl[i].nfb_count); | |
1076 | } | |
1077 | } | |
1078 | mutex_unlock(&nfsd_mutex); | |
1079 | ||
1080 | for_each_possible_cpu(i) | |
1081 | hits += per_cpu(nfsd_file_cache_hits, i); | |
1082 | ||
1083 | seq_printf(m, "total entries: %u\n", count); | |
1084 | seq_printf(m, "longest chain: %u\n", longest); | |
1085 | seq_printf(m, "cache hits: %lu\n", hits); | |
1086 | return 0; | |
1087 | } | |
1088 | ||
1089 | int nfsd_file_cache_stats_open(struct inode *inode, struct file *file) | |
1090 | { | |
1091 | return single_open(file, nfsd_file_cache_stats_show, NULL); | |
1092 | } |