1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * The NFSD open file cache. |
4 | * |
5 | * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com> |
6 | * |
7 | * An nfsd_file object is a per-file collection of open state that binds |
8 | * together: |
9 | * - a struct file * |
10 | * - a user credential |
11 | * - a network namespace |
12 | * - a read-ahead context |
13 | * - monitoring for writeback errors |
14 | * |
15 | * nfsd_file objects are reference-counted. Consumers acquire a new |
16 | * object via the nfsd_file_acquire API. They manage their interest in |
17 | * the acquired object, and hence the object's reference count, via |
18 | * nfsd_file_get and nfsd_file_put. There are two varieties of nfsd_file |
19 | * object: |
20 | * |
21 | * * non-garbage-collected: When a consumer wants to precisely control |
22 | * the lifetime of a file's open state, it acquires a non-garbage- |
23 | * collected nfsd_file. The final nfsd_file_put releases the open |
24 | * state immediately. |
25 | * |
26 | * * garbage-collected: When a consumer does not control the lifetime |
27 | * of open state, it acquires a garbage-collected nfsd_file. The |
28 | * final nfsd_file_put allows the open state to linger for a period |
29 | * during which it may be re-used. |
30 | */ |
31 | |
32 | #include <linux/hash.h> |
33 | #include <linux/slab.h> |
34 | #include <linux/file.h> |
35 | #include <linux/pagemap.h> |
36 | #include <linux/sched.h> |
37 | #include <linux/list_lru.h> |
38 | #include <linux/fsnotify_backend.h> |
39 | #include <linux/fsnotify.h> |
40 | #include <linux/seq_file.h> |
41 | #include <linux/rhashtable.h> |
42 | |
43 | #include "vfs.h" |
44 | #include "nfsd.h" |
45 | #include "nfsfh.h" |
46 | #include "netns.h" |
47 | #include "filecache.h" |
48 | #include "trace.h" |
49 | |
50 | #define NFSD_LAUNDRETTE_DELAY (2 * HZ) |
51 | |
52 | #define NFSD_FILE_CACHE_UP (0) |
53 | |
54 | /* We only care about NFSD_MAY_READ/WRITE for this cache */ |
55 | #define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE) |
56 | |
57 | static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits); |
58 | static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions); |
59 | static DEFINE_PER_CPU(unsigned long, nfsd_file_releases); |
60 | static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age); |
61 | static DEFINE_PER_CPU(unsigned long, nfsd_file_evictions); |
62 | |
63 | struct nfsd_fcache_disposal { |
64 | spinlock_t lock; |
65 | struct list_head freeme; |
66 | }; |
67 | |
68 | static struct kmem_cache *nfsd_file_slab; |
69 | static struct kmem_cache *nfsd_file_mark_slab; |
70 | static struct list_lru nfsd_file_lru; |
71 | static unsigned long nfsd_file_flags; |
72 | static struct fsnotify_group *nfsd_file_fsnotify_group; |
73 | static struct delayed_work nfsd_filecache_laundrette; |
74 | static struct rhltable nfsd_file_rhltable |
75 | ____cacheline_aligned_in_smp; |
76 | |
77 | static bool |
78 | nfsd_match_cred(const struct cred *c1, const struct cred *c2) |
79 | { |
80 | int i; |
81 | |
82 | if (!uid_eq(left: c1->fsuid, right: c2->fsuid)) |
83 | return false; |
84 | if (!gid_eq(left: c1->fsgid, right: c2->fsgid)) |
85 | return false; |
86 | if (c1->group_info == NULL || c2->group_info == NULL) |
87 | return c1->group_info == c2->group_info; |
88 | if (c1->group_info->ngroups != c2->group_info->ngroups) |
89 | return false; |
90 | for (i = 0; i < c1->group_info->ngroups; i++) { |
91 | if (!gid_eq(left: c1->group_info->gid[i], right: c2->group_info->gid[i])) |
92 | return false; |
93 | } |
94 | return true; |
95 | } |
96 | |
97 | static const struct rhashtable_params nfsd_file_rhash_params = { |
98 | .key_len = sizeof_field(struct nfsd_file, nf_inode), |
99 | .key_offset = offsetof(struct nfsd_file, nf_inode), |
100 | .head_offset = offsetof(struct nfsd_file, nf_rlist), |
101 | |
102 | /* |
103 | * Start with a single page hash table to reduce resizing churn |
104 | * on light workloads. |
105 | */ |
106 | .min_size = 256, |
107 | .automatic_shrinking = true, |
108 | }; |
109 | |
110 | static void |
111 | nfsd_file_schedule_laundrette(void) |
112 | { |
113 | if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags)) |
114 | queue_delayed_work(wq: system_wq, dwork: &nfsd_filecache_laundrette, |
115 | NFSD_LAUNDRETTE_DELAY); |
116 | } |
117 | |
118 | static void |
119 | nfsd_file_slab_free(struct rcu_head *rcu) |
120 | { |
121 | struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu); |
122 | |
123 | put_cred(cred: nf->nf_cred); |
124 | kmem_cache_free(s: nfsd_file_slab, objp: nf); |
125 | } |
126 | |
127 | static void |
128 | nfsd_file_mark_free(struct fsnotify_mark *mark) |
129 | { |
130 | struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark, |
131 | nfm_mark); |
132 | |
133 | kmem_cache_free(s: nfsd_file_mark_slab, objp: nfm); |
134 | } |
135 | |
136 | static struct nfsd_file_mark * |
137 | nfsd_file_mark_get(struct nfsd_file_mark *nfm) |
138 | { |
139 | if (!refcount_inc_not_zero(r: &nfm->nfm_ref)) |
140 | return NULL; |
141 | return nfm; |
142 | } |
143 | |
144 | static void |
145 | nfsd_file_mark_put(struct nfsd_file_mark *nfm) |
146 | { |
147 | if (refcount_dec_and_test(r: &nfm->nfm_ref)) { |
148 | fsnotify_destroy_mark(mark: &nfm->nfm_mark, group: nfsd_file_fsnotify_group); |
149 | fsnotify_put_mark(mark: &nfm->nfm_mark); |
150 | } |
151 | } |
152 | |
153 | static struct nfsd_file_mark * |
154 | nfsd_file_mark_find_or_create(struct nfsd_file *nf, struct inode *inode) |
155 | { |
156 | int err; |
157 | struct fsnotify_mark *mark; |
158 | struct nfsd_file_mark *nfm = NULL, *new; |
159 | |
160 | do { |
161 | fsnotify_group_lock(group: nfsd_file_fsnotify_group); |
162 | mark = fsnotify_find_mark(connp: &inode->i_fsnotify_marks, |
163 | group: nfsd_file_fsnotify_group); |
164 | if (mark) { |
165 | nfm = nfsd_file_mark_get(container_of(mark, |
166 | struct nfsd_file_mark, |
167 | nfm_mark)); |
168 | fsnotify_group_unlock(group: nfsd_file_fsnotify_group); |
169 | if (nfm) { |
170 | fsnotify_put_mark(mark); |
171 | break; |
172 | } |
173 | /* Avoid soft lockup race with nfsd_file_mark_put() */ |
174 | fsnotify_destroy_mark(mark, group: nfsd_file_fsnotify_group); |
175 | fsnotify_put_mark(mark); |
176 | } else { |
177 | fsnotify_group_unlock(group: nfsd_file_fsnotify_group); |
178 | } |
179 | |
180 | /* allocate a new nfm */ |
181 | new = kmem_cache_alloc(cachep: nfsd_file_mark_slab, GFP_KERNEL); |
182 | if (!new) |
183 | return NULL; |
184 | fsnotify_init_mark(mark: &new->nfm_mark, group: nfsd_file_fsnotify_group); |
185 | new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF; |
186 | refcount_set(r: &new->nfm_ref, n: 1); |
187 | |
188 | err = fsnotify_add_inode_mark(mark: &new->nfm_mark, inode, add_flags: 0); |
189 | |
190 | /* |
191 | * If the add was successful, then return the object. |
192 | * Otherwise, we need to put the reference we hold on the |
193 | * nfm_mark. The fsnotify code will take a reference and put |
194 | * it on failure, so we can't just free it directly. It's also |
195 | * not safe to call fsnotify_destroy_mark on it as the |
196 | * mark->group will be NULL. Thus, we can't let the nfm_ref |
197 | * counter drive the destruction at this point. |
198 | */ |
199 | if (likely(!err)) |
200 | nfm = new; |
201 | else |
202 | fsnotify_put_mark(mark: &new->nfm_mark); |
203 | } while (unlikely(err == -EEXIST)); |
204 | |
205 | return nfm; |
206 | } |
207 | |
208 | static struct nfsd_file * |
209 | nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need, |
210 | bool want_gc) |
211 | { |
212 | struct nfsd_file *nf; |
213 | |
214 | nf = kmem_cache_alloc(cachep: nfsd_file_slab, GFP_KERNEL); |
215 | if (unlikely(!nf)) |
216 | return NULL; |
217 | |
218 | INIT_LIST_HEAD(list: &nf->nf_lru); |
219 | nf->nf_birthtime = ktime_get(); |
220 | nf->nf_file = NULL; |
221 | nf->nf_cred = get_current_cred(); |
222 | nf->nf_net = net; |
223 | nf->nf_flags = want_gc ? |
224 | BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING) | BIT(NFSD_FILE_GC) : |
225 | BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING); |
226 | nf->nf_inode = inode; |
227 | refcount_set(r: &nf->nf_ref, n: 1); |
228 | nf->nf_may = need; |
229 | nf->nf_mark = NULL; |
230 | return nf; |
231 | } |
232 | |
233 | /** |
234 | * nfsd_file_check_write_error - check for writeback errors on a file |
235 | * @nf: nfsd_file to check for writeback errors |
236 | * |
237 | * Check whether a nfsd_file has an unseen error. Reset the write |
238 | * verifier if so. |
239 | */ |
240 | static void |
241 | nfsd_file_check_write_error(struct nfsd_file *nf) |
242 | { |
243 | struct file *file = nf->nf_file; |
244 | |
245 | if ((file->f_mode & FMODE_WRITE) && |
246 | filemap_check_wb_err(mapping: file->f_mapping, READ_ONCE(file->f_wb_err))) |
247 | nfsd_reset_write_verifier(nn: net_generic(net: nf->nf_net, id: nfsd_net_id)); |
248 | } |
249 | |
250 | static void |
251 | nfsd_file_hash_remove(struct nfsd_file *nf) |
252 | { |
253 | trace_nfsd_file_unhash(nf); |
254 | rhltable_remove(hlt: &nfsd_file_rhltable, list: &nf->nf_rlist, |
255 | params: nfsd_file_rhash_params); |
256 | } |
257 | |
258 | static bool |
259 | nfsd_file_unhash(struct nfsd_file *nf) |
260 | { |
261 | if (test_and_clear_bit(NFSD_FILE_HASHED, addr: &nf->nf_flags)) { |
262 | nfsd_file_hash_remove(nf); |
263 | return true; |
264 | } |
265 | return false; |
266 | } |
267 | |
268 | static void |
269 | nfsd_file_free(struct nfsd_file *nf) |
270 | { |
271 | s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime)); |
272 | |
273 | trace_nfsd_file_free(nf); |
274 | |
275 | this_cpu_inc(nfsd_file_releases); |
276 | this_cpu_add(nfsd_file_total_age, age); |
277 | |
278 | nfsd_file_unhash(nf); |
279 | if (nf->nf_mark) |
280 | nfsd_file_mark_put(nfm: nf->nf_mark); |
281 | if (nf->nf_file) { |
282 | nfsd_file_check_write_error(nf); |
283 | nfsd_filp_close(fp: nf->nf_file); |
284 | } |
285 | |
286 | /* |
287 | * If this item is still linked via nf_lru, that's a bug. |
288 | * WARN and leak it to preserve system stability. |
289 | */ |
290 | if (WARN_ON_ONCE(!list_empty(&nf->nf_lru))) |
291 | return; |
292 | |
293 | call_rcu(head: &nf->nf_rcu, func: nfsd_file_slab_free); |
294 | } |
295 | |
296 | static bool |
297 | nfsd_file_check_writeback(struct nfsd_file *nf) |
298 | { |
299 | struct file *file = nf->nf_file; |
300 | struct address_space *mapping; |
301 | |
302 | /* File not open for write? */ |
303 | if (!(file->f_mode & FMODE_WRITE)) |
304 | return false; |
305 | |
306 | /* |
307 | * Some filesystems (e.g. NFS) flush all dirty data on close. |
308 | * On others, there is no need to wait for writeback. |
309 | */ |
310 | if (!(file_inode(f: file)->i_sb->s_export_op->flags & EXPORT_OP_FLUSH_ON_CLOSE)) |
311 | return false; |
312 | |
313 | mapping = file->f_mapping; |
314 | return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) || |
315 | mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK); |
316 | } |
317 | |
318 | |
319 | static bool nfsd_file_lru_add(struct nfsd_file *nf) |
320 | { |
321 | set_bit(NFSD_FILE_REFERENCED, addr: &nf->nf_flags); |
322 | if (list_lru_add_obj(lru: &nfsd_file_lru, item: &nf->nf_lru)) { |
323 | trace_nfsd_file_lru_add(nf); |
324 | return true; |
325 | } |
326 | return false; |
327 | } |
328 | |
329 | static bool nfsd_file_lru_remove(struct nfsd_file *nf) |
330 | { |
331 | if (list_lru_del_obj(lru: &nfsd_file_lru, item: &nf->nf_lru)) { |
332 | trace_nfsd_file_lru_del(nf); |
333 | return true; |
334 | } |
335 | return false; |
336 | } |
337 | |
338 | struct nfsd_file * |
339 | nfsd_file_get(struct nfsd_file *nf) |
340 | { |
341 | if (nf && refcount_inc_not_zero(r: &nf->nf_ref)) |
342 | return nf; |
343 | return NULL; |
344 | } |
345 | |
346 | /** |
347 | * nfsd_file_put - put the reference to a nfsd_file |
348 | * @nf: nfsd_file of which to put the reference |
349 | * |
350 | * Put a reference to a nfsd_file. In the non-GC case, we just put the |
351 | * reference immediately. In the GC case, if the reference would be |
352 | * the last one, the put it on the LRU instead to be cleaned up later. |
353 | */ |
354 | void |
355 | nfsd_file_put(struct nfsd_file *nf) |
356 | { |
357 | might_sleep(); |
358 | trace_nfsd_file_put(nf); |
359 | |
360 | if (test_bit(NFSD_FILE_GC, &nf->nf_flags) && |
361 | test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { |
362 | /* |
363 | * If this is the last reference (nf_ref == 1), then try to |
364 | * transfer it to the LRU. |
365 | */ |
366 | if (refcount_dec_not_one(r: &nf->nf_ref)) |
367 | return; |
368 | |
369 | /* Try to add it to the LRU. If that fails, decrement. */ |
370 | if (nfsd_file_lru_add(nf)) { |
371 | /* If it's still hashed, we're done */ |
372 | if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { |
373 | nfsd_file_schedule_laundrette(); |
374 | return; |
375 | } |
376 | |
377 | /* |
378 | * We're racing with unhashing, so try to remove it from |
379 | * the LRU. If removal fails, then someone else already |
380 | * has our reference. |
381 | */ |
382 | if (!nfsd_file_lru_remove(nf)) |
383 | return; |
384 | } |
385 | } |
386 | if (refcount_dec_and_test(r: &nf->nf_ref)) |
387 | nfsd_file_free(nf); |
388 | } |
389 | |
390 | static void |
391 | nfsd_file_dispose_list(struct list_head *dispose) |
392 | { |
393 | struct nfsd_file *nf; |
394 | |
395 | while (!list_empty(head: dispose)) { |
396 | nf = list_first_entry(dispose, struct nfsd_file, nf_lru); |
397 | list_del_init(entry: &nf->nf_lru); |
398 | nfsd_file_free(nf); |
399 | } |
400 | } |
401 | |
402 | /** |
403 | * nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list |
404 | * @dispose: list of nfsd_files to be disposed |
405 | * |
406 | * Transfers each file to the "freeme" list for its nfsd_net, to eventually |
407 | * be disposed of by the per-net garbage collector. |
408 | */ |
409 | static void |
410 | nfsd_file_dispose_list_delayed(struct list_head *dispose) |
411 | { |
412 | while(!list_empty(head: dispose)) { |
413 | struct nfsd_file *nf = list_first_entry(dispose, |
414 | struct nfsd_file, nf_lru); |
415 | struct nfsd_net *nn = net_generic(net: nf->nf_net, id: nfsd_net_id); |
416 | struct nfsd_fcache_disposal *l = nn->fcache_disposal; |
417 | |
418 | spin_lock(lock: &l->lock); |
419 | list_move_tail(list: &nf->nf_lru, head: &l->freeme); |
420 | spin_unlock(lock: &l->lock); |
421 | svc_wake_up(nn->nfsd_serv); |
422 | } |
423 | } |
424 | |
425 | /** |
426 | * nfsd_file_net_dispose - deal with nfsd_files waiting to be disposed. |
427 | * @nn: nfsd_net in which to find files to be disposed. |
428 | * |
429 | * When files held open for nfsv3 are removed from the filecache, whether |
430 | * due to memory pressure or garbage collection, they are queued to |
431 | * a per-net-ns queue. This function completes the disposal, either |
432 | * directly or by waking another nfsd thread to help with the work. |
433 | */ |
434 | void nfsd_file_net_dispose(struct nfsd_net *nn) |
435 | { |
436 | struct nfsd_fcache_disposal *l = nn->fcache_disposal; |
437 | |
438 | if (!list_empty(head: &l->freeme)) { |
439 | LIST_HEAD(dispose); |
440 | int i; |
441 | |
442 | spin_lock(lock: &l->lock); |
443 | for (i = 0; i < 8 && !list_empty(head: &l->freeme); i++) |
444 | list_move(list: l->freeme.next, head: &dispose); |
445 | spin_unlock(lock: &l->lock); |
446 | if (!list_empty(head: &l->freeme)) |
447 | /* Wake up another thread to share the work |
448 | * *before* doing any actual disposing. |
449 | */ |
450 | svc_wake_up(nn->nfsd_serv); |
451 | nfsd_file_dispose_list(dispose: &dispose); |
452 | } |
453 | } |
454 | |
455 | /** |
456 | * nfsd_file_lru_cb - Examine an entry on the LRU list |
457 | * @item: LRU entry to examine |
458 | * @lru: controlling LRU |
459 | * @lock: LRU list lock (unused) |
460 | * @arg: dispose list |
461 | * |
462 | * Return values: |
463 | * %LRU_REMOVED: @item was removed from the LRU |
464 | * %LRU_ROTATE: @item is to be moved to the LRU tail |
465 | * %LRU_SKIP: @item cannot be evicted |
466 | */ |
467 | static enum lru_status |
468 | nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, |
469 | spinlock_t *lock, void *arg) |
470 | __releases(lock) |
471 | __acquires(lock) |
472 | { |
473 | struct list_head *head = arg; |
474 | struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru); |
475 | |
476 | /* We should only be dealing with GC entries here */ |
477 | WARN_ON_ONCE(!test_bit(NFSD_FILE_GC, &nf->nf_flags)); |
478 | |
479 | /* |
480 | * Don't throw out files that are still undergoing I/O or |
481 | * that have uncleared errors pending. |
482 | */ |
483 | if (nfsd_file_check_writeback(nf)) { |
484 | trace_nfsd_file_gc_writeback(nf); |
485 | return LRU_SKIP; |
486 | } |
487 | |
488 | /* If it was recently added to the list, skip it */ |
489 | if (test_and_clear_bit(NFSD_FILE_REFERENCED, addr: &nf->nf_flags)) { |
490 | trace_nfsd_file_gc_referenced(nf); |
491 | return LRU_ROTATE; |
492 | } |
493 | |
494 | /* |
495 | * Put the reference held on behalf of the LRU. If it wasn't the last |
496 | * one, then just remove it from the LRU and ignore it. |
497 | */ |
498 | if (!refcount_dec_and_test(r: &nf->nf_ref)) { |
499 | trace_nfsd_file_gc_in_use(nf); |
500 | list_lru_isolate(list: lru, item: &nf->nf_lru); |
501 | return LRU_REMOVED; |
502 | } |
503 | |
504 | /* Refcount went to zero. Unhash it and queue it to the dispose list */ |
505 | nfsd_file_unhash(nf); |
506 | list_lru_isolate_move(list: lru, item: &nf->nf_lru, head); |
507 | this_cpu_inc(nfsd_file_evictions); |
508 | trace_nfsd_file_gc_disposed(nf); |
509 | return LRU_REMOVED; |
510 | } |
511 | |
512 | static void |
513 | nfsd_file_gc(void) |
514 | { |
515 | LIST_HEAD(dispose); |
516 | unsigned long ret; |
517 | |
518 | ret = list_lru_walk(lru: &nfsd_file_lru, isolate: nfsd_file_lru_cb, |
519 | cb_arg: &dispose, nr_to_walk: list_lru_count(lru: &nfsd_file_lru)); |
520 | trace_nfsd_file_gc_removed(removed: ret, remaining: list_lru_count(lru: &nfsd_file_lru)); |
521 | nfsd_file_dispose_list_delayed(dispose: &dispose); |
522 | } |
523 | |
524 | static void |
525 | nfsd_file_gc_worker(struct work_struct *work) |
526 | { |
527 | nfsd_file_gc(); |
528 | if (list_lru_count(lru: &nfsd_file_lru)) |
529 | nfsd_file_schedule_laundrette(); |
530 | } |
531 | |
532 | static unsigned long |
533 | nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc) |
534 | { |
535 | return list_lru_count(lru: &nfsd_file_lru); |
536 | } |
537 | |
538 | static unsigned long |
539 | nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc) |
540 | { |
541 | LIST_HEAD(dispose); |
542 | unsigned long ret; |
543 | |
544 | ret = list_lru_shrink_walk(lru: &nfsd_file_lru, sc, |
545 | isolate: nfsd_file_lru_cb, cb_arg: &dispose); |
546 | trace_nfsd_file_shrinker_removed(removed: ret, remaining: list_lru_count(lru: &nfsd_file_lru)); |
547 | nfsd_file_dispose_list_delayed(dispose: &dispose); |
548 | return ret; |
549 | } |
550 | |
551 | static struct shrinker *nfsd_file_shrinker; |
552 | |
553 | /** |
554 | * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file |
555 | * @nf: nfsd_file to attempt to queue |
556 | * @dispose: private list to queue successfully-put objects |
557 | * |
558 | * Unhash an nfsd_file, try to get a reference to it, and then put that |
559 | * reference. If it's the last reference, queue it to the dispose list. |
560 | */ |
561 | static void |
562 | nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose) |
563 | __must_hold(RCU) |
564 | { |
565 | int decrement = 1; |
566 | |
567 | /* If we raced with someone else unhashing, ignore it */ |
568 | if (!nfsd_file_unhash(nf)) |
569 | return; |
570 | |
571 | /* If we can't get a reference, ignore it */ |
572 | if (!nfsd_file_get(nf)) |
573 | return; |
574 | |
575 | /* Extra decrement if we remove from the LRU */ |
576 | if (nfsd_file_lru_remove(nf)) |
577 | ++decrement; |
578 | |
579 | /* If refcount goes to 0, then put on the dispose list */ |
580 | if (refcount_sub_and_test(i: decrement, r: &nf->nf_ref)) { |
581 | list_add(new: &nf->nf_lru, head: dispose); |
582 | trace_nfsd_file_closing(nf); |
583 | } |
584 | } |
585 | |
586 | /** |
587 | * nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode |
588 | * @inode: inode on which to close out nfsd_files |
589 | * @dispose: list on which to gather nfsd_files to close out |
590 | * |
591 | * An nfsd_file represents a struct file being held open on behalf of nfsd. |
592 | * An open file however can block other activity (such as leases), or cause |
593 | * undesirable behavior (e.g. spurious silly-renames when reexporting NFS). |
594 | * |
595 | * This function is intended to find open nfsd_files when this sort of |
596 | * conflicting access occurs and then attempt to close those files out. |
597 | * |
598 | * Populates the dispose list with entries that have already had their |
599 | * refcounts go to zero. The actual free of an nfsd_file can be expensive, |
600 | * so we leave it up to the caller whether it wants to wait or not. |
601 | */ |
602 | static void |
603 | nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose) |
604 | { |
605 | struct rhlist_head *tmp, *list; |
606 | struct nfsd_file *nf; |
607 | |
608 | rcu_read_lock(); |
609 | list = rhltable_lookup(hlt: &nfsd_file_rhltable, key: &inode, |
610 | params: nfsd_file_rhash_params); |
611 | rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) { |
612 | if (!test_bit(NFSD_FILE_GC, &nf->nf_flags)) |
613 | continue; |
614 | nfsd_file_cond_queue(nf, dispose); |
615 | } |
616 | rcu_read_unlock(); |
617 | } |
618 | |
619 | /** |
620 | * nfsd_file_close_inode - attempt a delayed close of a nfsd_file |
621 | * @inode: inode of the file to attempt to remove |
622 | * |
623 | * Close out any open nfsd_files that can be reaped for @inode. The |
624 | * actual freeing is deferred to the dispose_list_delayed infrastructure. |
625 | * |
626 | * This is used by the fsnotify callbacks and setlease notifier. |
627 | */ |
628 | static void |
629 | nfsd_file_close_inode(struct inode *inode) |
630 | { |
631 | LIST_HEAD(dispose); |
632 | |
633 | nfsd_file_queue_for_close(inode, dispose: &dispose); |
634 | nfsd_file_dispose_list_delayed(dispose: &dispose); |
635 | } |
636 | |
637 | /** |
638 | * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file |
639 | * @inode: inode of the file to attempt to remove |
640 | * |
641 | * Close out any open nfsd_files that can be reaped for @inode. The |
642 | * nfsd_files are closed out synchronously. |
643 | * |
644 | * This is called from nfsd_rename and nfsd_unlink to avoid silly-renames |
645 | * when reexporting NFS. |
646 | */ |
647 | void |
648 | nfsd_file_close_inode_sync(struct inode *inode) |
649 | { |
650 | struct nfsd_file *nf; |
651 | LIST_HEAD(dispose); |
652 | |
653 | trace_nfsd_file_close(inode); |
654 | |
655 | nfsd_file_queue_for_close(inode, dispose: &dispose); |
656 | while (!list_empty(head: &dispose)) { |
657 | nf = list_first_entry(&dispose, struct nfsd_file, nf_lru); |
658 | list_del_init(entry: &nf->nf_lru); |
659 | nfsd_file_free(nf); |
660 | } |
661 | } |
662 | |
663 | static int |
664 | nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg, |
665 | void *data) |
666 | { |
667 | struct file_lock *fl = data; |
668 | |
669 | /* Only close files for F_SETLEASE leases */ |
670 | if (fl->c.flc_flags & FL_LEASE) |
671 | nfsd_file_close_inode(inode: file_inode(f: fl->c.flc_file)); |
672 | return 0; |
673 | } |
674 | |
675 | static struct notifier_block nfsd_file_lease_notifier = { |
676 | .notifier_call = nfsd_file_lease_notifier_call, |
677 | }; |
678 | |
679 | static int |
680 | nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask, |
681 | struct inode *inode, struct inode *dir, |
682 | const struct qstr *name, u32 cookie) |
683 | { |
684 | if (WARN_ON_ONCE(!inode)) |
685 | return 0; |
686 | |
687 | trace_nfsd_file_fsnotify_handle_event(inode, mask); |
688 | |
689 | /* Should be no marks on non-regular files */ |
690 | if (!S_ISREG(inode->i_mode)) { |
691 | WARN_ON_ONCE(1); |
692 | return 0; |
693 | } |
694 | |
695 | /* don't close files if this was not the last link */ |
696 | if (mask & FS_ATTRIB) { |
697 | if (inode->i_nlink) |
698 | return 0; |
699 | } |
700 | |
701 | nfsd_file_close_inode(inode); |
702 | return 0; |
703 | } |
704 | |
705 | |
706 | static const struct fsnotify_ops nfsd_file_fsnotify_ops = { |
707 | .handle_inode_event = nfsd_file_fsnotify_handle_event, |
708 | .free_mark = nfsd_file_mark_free, |
709 | }; |
710 | |
711 | int |
712 | nfsd_file_cache_init(void) |
713 | { |
714 | int ret; |
715 | |
716 | lockdep_assert_held(&nfsd_mutex); |
717 | if (test_and_set_bit(NFSD_FILE_CACHE_UP, addr: &nfsd_file_flags) == 1) |
718 | return 0; |
719 | |
720 | ret = rhltable_init(hlt: &nfsd_file_rhltable, params: &nfsd_file_rhash_params); |
721 | if (ret) |
722 | return ret; |
723 | |
724 | ret = -ENOMEM; |
725 | nfsd_file_slab = KMEM_CACHE(nfsd_file, 0); |
726 | if (!nfsd_file_slab) { |
727 | pr_err("nfsd: unable to create nfsd_file_slab\n" ); |
728 | goto out_err; |
729 | } |
730 | |
731 | nfsd_file_mark_slab = KMEM_CACHE(nfsd_file_mark, 0); |
732 | if (!nfsd_file_mark_slab) { |
733 | pr_err("nfsd: unable to create nfsd_file_mark_slab\n" ); |
734 | goto out_err; |
735 | } |
736 | |
737 | ret = list_lru_init(&nfsd_file_lru); |
738 | if (ret) { |
739 | pr_err("nfsd: failed to init nfsd_file_lru: %d\n" , ret); |
740 | goto out_err; |
741 | } |
742 | |
743 | nfsd_file_shrinker = shrinker_alloc(flags: 0, fmt: "nfsd-filecache" ); |
744 | if (!nfsd_file_shrinker) { |
745 | ret = -ENOMEM; |
746 | pr_err("nfsd: failed to allocate nfsd_file_shrinker\n" ); |
747 | goto out_lru; |
748 | } |
749 | |
750 | nfsd_file_shrinker->count_objects = nfsd_file_lru_count; |
751 | nfsd_file_shrinker->scan_objects = nfsd_file_lru_scan; |
752 | nfsd_file_shrinker->seeks = 1; |
753 | |
754 | shrinker_register(shrinker: nfsd_file_shrinker); |
755 | |
756 | ret = lease_register_notifier(&nfsd_file_lease_notifier); |
757 | if (ret) { |
758 | pr_err("nfsd: unable to register lease notifier: %d\n" , ret); |
759 | goto out_shrinker; |
760 | } |
761 | |
762 | nfsd_file_fsnotify_group = fsnotify_alloc_group(ops: &nfsd_file_fsnotify_ops, |
763 | FSNOTIFY_GROUP_NOFS); |
764 | if (IS_ERR(ptr: nfsd_file_fsnotify_group)) { |
765 | pr_err("nfsd: unable to create fsnotify group: %ld\n" , |
766 | PTR_ERR(nfsd_file_fsnotify_group)); |
767 | ret = PTR_ERR(ptr: nfsd_file_fsnotify_group); |
768 | nfsd_file_fsnotify_group = NULL; |
769 | goto out_notifier; |
770 | } |
771 | |
772 | INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker); |
773 | out: |
774 | return ret; |
775 | out_notifier: |
776 | lease_unregister_notifier(&nfsd_file_lease_notifier); |
777 | out_shrinker: |
778 | shrinker_free(shrinker: nfsd_file_shrinker); |
779 | out_lru: |
780 | list_lru_destroy(lru: &nfsd_file_lru); |
781 | out_err: |
782 | kmem_cache_destroy(s: nfsd_file_slab); |
783 | nfsd_file_slab = NULL; |
784 | kmem_cache_destroy(s: nfsd_file_mark_slab); |
785 | nfsd_file_mark_slab = NULL; |
786 | rhltable_destroy(hlt: &nfsd_file_rhltable); |
787 | goto out; |
788 | } |
789 | |
790 | /** |
791 | * __nfsd_file_cache_purge: clean out the cache for shutdown |
792 | * @net: net-namespace to shut down the cache (may be NULL) |
793 | * |
794 | * Walk the nfsd_file cache and close out any that match @net. If @net is NULL, |
795 | * then close out everything. Called when an nfsd instance is being shut down, |
796 | * and when the exports table is flushed. |
797 | */ |
798 | static void |
799 | __nfsd_file_cache_purge(struct net *net) |
800 | { |
801 | struct rhashtable_iter iter; |
802 | struct nfsd_file *nf; |
803 | LIST_HEAD(dispose); |
804 | |
805 | rhltable_walk_enter(hlt: &nfsd_file_rhltable, iter: &iter); |
806 | do { |
807 | rhashtable_walk_start(iter: &iter); |
808 | |
809 | nf = rhashtable_walk_next(iter: &iter); |
810 | while (!IS_ERR_OR_NULL(ptr: nf)) { |
811 | if (!net || nf->nf_net == net) |
812 | nfsd_file_cond_queue(nf, dispose: &dispose); |
813 | nf = rhashtable_walk_next(iter: &iter); |
814 | } |
815 | |
816 | rhashtable_walk_stop(iter: &iter); |
817 | } while (nf == ERR_PTR(error: -EAGAIN)); |
818 | rhashtable_walk_exit(iter: &iter); |
819 | |
820 | nfsd_file_dispose_list(dispose: &dispose); |
821 | } |
822 | |
823 | static struct nfsd_fcache_disposal * |
824 | nfsd_alloc_fcache_disposal(void) |
825 | { |
826 | struct nfsd_fcache_disposal *l; |
827 | |
828 | l = kmalloc(size: sizeof(*l), GFP_KERNEL); |
829 | if (!l) |
830 | return NULL; |
831 | spin_lock_init(&l->lock); |
832 | INIT_LIST_HEAD(list: &l->freeme); |
833 | return l; |
834 | } |
835 | |
836 | static void |
837 | nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) |
838 | { |
839 | nfsd_file_dispose_list(dispose: &l->freeme); |
840 | kfree(objp: l); |
841 | } |
842 | |
843 | static void |
844 | nfsd_free_fcache_disposal_net(struct net *net) |
845 | { |
846 | struct nfsd_net *nn = net_generic(net, id: nfsd_net_id); |
847 | struct nfsd_fcache_disposal *l = nn->fcache_disposal; |
848 | |
849 | nfsd_free_fcache_disposal(l); |
850 | } |
851 | |
852 | int |
853 | nfsd_file_cache_start_net(struct net *net) |
854 | { |
855 | struct nfsd_net *nn = net_generic(net, id: nfsd_net_id); |
856 | |
857 | nn->fcache_disposal = nfsd_alloc_fcache_disposal(); |
858 | return nn->fcache_disposal ? 0 : -ENOMEM; |
859 | } |
860 | |
861 | /** |
862 | * nfsd_file_cache_purge - Remove all cache items associated with @net |
863 | * @net: target net namespace |
864 | * |
865 | */ |
866 | void |
867 | nfsd_file_cache_purge(struct net *net) |
868 | { |
869 | lockdep_assert_held(&nfsd_mutex); |
870 | if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) |
871 | __nfsd_file_cache_purge(net); |
872 | } |
873 | |
874 | void |
875 | nfsd_file_cache_shutdown_net(struct net *net) |
876 | { |
877 | nfsd_file_cache_purge(net); |
878 | nfsd_free_fcache_disposal_net(net); |
879 | } |
880 | |
881 | void |
882 | nfsd_file_cache_shutdown(void) |
883 | { |
884 | int i; |
885 | |
886 | lockdep_assert_held(&nfsd_mutex); |
887 | if (test_and_clear_bit(NFSD_FILE_CACHE_UP, addr: &nfsd_file_flags) == 0) |
888 | return; |
889 | |
890 | lease_unregister_notifier(&nfsd_file_lease_notifier); |
891 | shrinker_free(shrinker: nfsd_file_shrinker); |
892 | /* |
893 | * make sure all callers of nfsd_file_lru_cb are done before |
894 | * calling nfsd_file_cache_purge |
895 | */ |
896 | cancel_delayed_work_sync(dwork: &nfsd_filecache_laundrette); |
897 | __nfsd_file_cache_purge(NULL); |
898 | list_lru_destroy(lru: &nfsd_file_lru); |
899 | rcu_barrier(); |
900 | fsnotify_put_group(group: nfsd_file_fsnotify_group); |
901 | nfsd_file_fsnotify_group = NULL; |
902 | kmem_cache_destroy(s: nfsd_file_slab); |
903 | nfsd_file_slab = NULL; |
904 | fsnotify_wait_marks_destroyed(); |
905 | kmem_cache_destroy(s: nfsd_file_mark_slab); |
906 | nfsd_file_mark_slab = NULL; |
907 | rhltable_destroy(hlt: &nfsd_file_rhltable); |
908 | |
909 | for_each_possible_cpu(i) { |
910 | per_cpu(nfsd_file_cache_hits, i) = 0; |
911 | per_cpu(nfsd_file_acquisitions, i) = 0; |
912 | per_cpu(nfsd_file_releases, i) = 0; |
913 | per_cpu(nfsd_file_total_age, i) = 0; |
914 | per_cpu(nfsd_file_evictions, i) = 0; |
915 | } |
916 | } |
917 | |
918 | static struct nfsd_file * |
919 | nfsd_file_lookup_locked(const struct net *net, const struct cred *cred, |
920 | struct inode *inode, unsigned char need, |
921 | bool want_gc) |
922 | { |
923 | struct rhlist_head *tmp, *list; |
924 | struct nfsd_file *nf; |
925 | |
926 | list = rhltable_lookup(hlt: &nfsd_file_rhltable, key: &inode, |
927 | params: nfsd_file_rhash_params); |
928 | rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) { |
929 | if (nf->nf_may != need) |
930 | continue; |
931 | if (nf->nf_net != net) |
932 | continue; |
933 | if (!nfsd_match_cred(c1: nf->nf_cred, c2: cred)) |
934 | continue; |
935 | if (test_bit(NFSD_FILE_GC, &nf->nf_flags) != want_gc) |
936 | continue; |
937 | if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) |
938 | continue; |
939 | |
940 | if (!nfsd_file_get(nf)) |
941 | continue; |
942 | return nf; |
943 | } |
944 | return NULL; |
945 | } |
946 | |
947 | /** |
948 | * nfsd_file_is_cached - are there any cached open files for this inode? |
949 | * @inode: inode to check |
950 | * |
951 | * The lookup matches inodes in all net namespaces and is atomic wrt |
952 | * nfsd_file_acquire(). |
953 | * |
954 | * Return values: |
955 | * %true: filecache contains at least one file matching this inode |
956 | * %false: filecache contains no files matching this inode |
957 | */ |
958 | bool |
959 | nfsd_file_is_cached(struct inode *inode) |
960 | { |
961 | struct rhlist_head *tmp, *list; |
962 | struct nfsd_file *nf; |
963 | bool ret = false; |
964 | |
965 | rcu_read_lock(); |
966 | list = rhltable_lookup(hlt: &nfsd_file_rhltable, key: &inode, |
967 | params: nfsd_file_rhash_params); |
968 | rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) |
969 | if (test_bit(NFSD_FILE_GC, &nf->nf_flags)) { |
970 | ret = true; |
971 | break; |
972 | } |
973 | rcu_read_unlock(); |
974 | |
975 | trace_nfsd_file_is_cached(inode, found: (int)ret); |
976 | return ret; |
977 | } |
978 | |
979 | static __be32 |
980 | nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, |
981 | unsigned int may_flags, struct file *file, |
982 | struct nfsd_file **pnf, bool want_gc) |
983 | { |
984 | unsigned char need = may_flags & NFSD_FILE_MAY_MASK; |
985 | struct net *net = SVC_NET(rqstp); |
986 | struct nfsd_file *new, *nf; |
987 | bool stale_retry = true; |
988 | bool open_retry = true; |
989 | struct inode *inode; |
990 | __be32 status; |
991 | int ret; |
992 | |
993 | retry: |
994 | status = fh_verify(rqstp, fhp, S_IFREG, |
995 | may_flags|NFSD_MAY_OWNER_OVERRIDE); |
996 | if (status != nfs_ok) |
997 | return status; |
998 | inode = d_inode(dentry: fhp->fh_dentry); |
999 | |
1000 | rcu_read_lock(); |
1001 | nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc); |
1002 | rcu_read_unlock(); |
1003 | |
1004 | if (nf) { |
1005 | /* |
1006 | * If the nf is on the LRU then it holds an extra reference |
1007 | * that must be put if it's removed. It had better not be |
1008 | * the last one however, since we should hold another. |
1009 | */ |
1010 | if (nfsd_file_lru_remove(nf)) |
1011 | WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref)); |
1012 | goto wait_for_construction; |
1013 | } |
1014 | |
1015 | new = nfsd_file_alloc(net, inode, need, want_gc); |
1016 | if (!new) { |
1017 | status = nfserr_jukebox; |
1018 | goto out; |
1019 | } |
1020 | |
1021 | rcu_read_lock(); |
1022 | spin_lock(lock: &inode->i_lock); |
1023 | nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc); |
1024 | if (unlikely(nf)) { |
1025 | spin_unlock(lock: &inode->i_lock); |
1026 | rcu_read_unlock(); |
1027 | nfsd_file_slab_free(rcu: &new->nf_rcu); |
1028 | goto wait_for_construction; |
1029 | } |
1030 | nf = new; |
1031 | ret = rhltable_insert(hlt: &nfsd_file_rhltable, list: &nf->nf_rlist, |
1032 | params: nfsd_file_rhash_params); |
1033 | spin_unlock(lock: &inode->i_lock); |
1034 | rcu_read_unlock(); |
1035 | if (likely(ret == 0)) |
1036 | goto open_file; |
1037 | |
1038 | if (ret == -EEXIST) |
1039 | goto retry; |
1040 | trace_nfsd_file_insert_err(rqstp, inode, may_flags, error: ret); |
1041 | status = nfserr_jukebox; |
1042 | goto construction_err; |
1043 | |
1044 | wait_for_construction: |
1045 | wait_on_bit(word: &nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE); |
1046 | |
1047 | /* Did construction of this file fail? */ |
1048 | if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { |
1049 | trace_nfsd_file_cons_err(rqstp, inode, may_flags, nf); |
1050 | if (!open_retry) { |
1051 | status = nfserr_jukebox; |
1052 | goto construction_err; |
1053 | } |
1054 | open_retry = false; |
1055 | fh_put(fhp); |
1056 | goto retry; |
1057 | } |
1058 | this_cpu_inc(nfsd_file_cache_hits); |
1059 | |
1060 | status = nfserrno(errno: nfsd_open_break_lease(file_inode(f: nf->nf_file), may_flags)); |
1061 | if (status != nfs_ok) { |
1062 | nfsd_file_put(nf); |
1063 | nf = NULL; |
1064 | } |
1065 | |
1066 | out: |
1067 | if (status == nfs_ok) { |
1068 | this_cpu_inc(nfsd_file_acquisitions); |
1069 | nfsd_file_check_write_error(nf); |
1070 | *pnf = nf; |
1071 | } |
1072 | trace_nfsd_file_acquire(rqstp, inode, may_flags, nf, status); |
1073 | return status; |
1074 | |
1075 | open_file: |
1076 | trace_nfsd_file_alloc(nf); |
1077 | nf->nf_mark = nfsd_file_mark_find_or_create(nf, inode); |
1078 | if (nf->nf_mark) { |
1079 | if (file) { |
1080 | get_file(f: file); |
1081 | nf->nf_file = file; |
1082 | status = nfs_ok; |
1083 | trace_nfsd_file_opened(nf, status); |
1084 | } else { |
1085 | ret = nfsd_open_verified(rqstp, fhp, may_flags, |
1086 | filp: &nf->nf_file); |
1087 | if (ret == -EOPENSTALE && stale_retry) { |
1088 | stale_retry = false; |
1089 | nfsd_file_unhash(nf); |
1090 | clear_and_wake_up_bit(NFSD_FILE_PENDING, |
1091 | word: &nf->nf_flags); |
1092 | if (refcount_dec_and_test(r: &nf->nf_ref)) |
1093 | nfsd_file_free(nf); |
1094 | nf = NULL; |
1095 | fh_put(fhp); |
1096 | goto retry; |
1097 | } |
1098 | status = nfserrno(errno: ret); |
1099 | trace_nfsd_file_open(nf, status); |
1100 | } |
1101 | } else |
1102 | status = nfserr_jukebox; |
1103 | /* |
1104 | * If construction failed, or we raced with a call to unlink() |
1105 | * then unhash. |
1106 | */ |
1107 | if (status != nfs_ok || inode->i_nlink == 0) |
1108 | nfsd_file_unhash(nf); |
1109 | clear_and_wake_up_bit(NFSD_FILE_PENDING, word: &nf->nf_flags); |
1110 | if (status == nfs_ok) |
1111 | goto out; |
1112 | |
1113 | construction_err: |
1114 | if (refcount_dec_and_test(r: &nf->nf_ref)) |
1115 | nfsd_file_free(nf); |
1116 | nf = NULL; |
1117 | goto out; |
1118 | } |
1119 | |
1120 | /** |
1121 | * nfsd_file_acquire_gc - Get a struct nfsd_file with an open file |
1122 | * @rqstp: the RPC transaction being executed |
1123 | * @fhp: the NFS filehandle of the file to be opened |
1124 | * @may_flags: NFSD_MAY_ settings for the file |
1125 | * @pnf: OUT: new or found "struct nfsd_file" object |
1126 | * |
1127 | * The nfsd_file object returned by this API is reference-counted |
1128 | * and garbage-collected. The object is retained for a few |
1129 | * seconds after the final nfsd_file_put() in case the caller |
1130 | * wants to re-use it. |
1131 | * |
1132 | * Return values: |
1133 | * %nfs_ok - @pnf points to an nfsd_file with its reference |
1134 | * count boosted. |
1135 | * |
1136 | * On error, an nfsstat value in network byte order is returned. |
1137 | */ |
1138 | __be32 |
1139 | nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp, |
1140 | unsigned int may_flags, struct nfsd_file **pnf) |
1141 | { |
1142 | return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, want_gc: true); |
1143 | } |
1144 | |
1145 | /** |
1146 | * nfsd_file_acquire - Get a struct nfsd_file with an open file |
1147 | * @rqstp: the RPC transaction being executed |
1148 | * @fhp: the NFS filehandle of the file to be opened |
1149 | * @may_flags: NFSD_MAY_ settings for the file |
1150 | * @pnf: OUT: new or found "struct nfsd_file" object |
1151 | * |
1152 | * The nfsd_file_object returned by this API is reference-counted |
1153 | * but not garbage-collected. The object is unhashed after the |
1154 | * final nfsd_file_put(). |
1155 | * |
1156 | * Return values: |
1157 | * %nfs_ok - @pnf points to an nfsd_file with its reference |
1158 | * count boosted. |
1159 | * |
1160 | * On error, an nfsstat value in network byte order is returned. |
1161 | */ |
1162 | __be32 |
1163 | nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, |
1164 | unsigned int may_flags, struct nfsd_file **pnf) |
1165 | { |
1166 | return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, want_gc: false); |
1167 | } |
1168 | |
1169 | /** |
1170 | * nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file |
1171 | * @rqstp: the RPC transaction being executed |
1172 | * @fhp: the NFS filehandle of the file just created |
1173 | * @may_flags: NFSD_MAY_ settings for the file |
1174 | * @file: cached, already-open file (may be NULL) |
1175 | * @pnf: OUT: new or found "struct nfsd_file" object |
1176 | * |
1177 | * Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist, |
1178 | * and @file is non-NULL, use it to instantiate a new nfsd_file instead of |
1179 | * opening a new one. |
1180 | * |
1181 | * Return values: |
1182 | * %nfs_ok - @pnf points to an nfsd_file with its reference |
1183 | * count boosted. |
1184 | * |
1185 | * On error, an nfsstat value in network byte order is returned. |
1186 | */ |
1187 | __be32 |
1188 | nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp, |
1189 | unsigned int may_flags, struct file *file, |
1190 | struct nfsd_file **pnf) |
1191 | { |
1192 | return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, want_gc: false); |
1193 | } |
1194 | |
1195 | /* |
1196 | * Note that fields may be added, removed or reordered in the future. Programs |
1197 | * scraping this file for info should test the labels to ensure they're |
1198 | * getting the correct field. |
1199 | */ |
1200 | int nfsd_file_cache_stats_show(struct seq_file *m, void *v) |
1201 | { |
1202 | unsigned long releases = 0, evictions = 0; |
1203 | unsigned long hits = 0, acquisitions = 0; |
1204 | unsigned int i, count = 0, buckets = 0; |
1205 | unsigned long lru = 0, total_age = 0; |
1206 | |
1207 | /* Serialize with server shutdown */ |
1208 | mutex_lock(&nfsd_mutex); |
1209 | if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) { |
1210 | struct bucket_table *tbl; |
1211 | struct rhashtable *ht; |
1212 | |
1213 | lru = list_lru_count(lru: &nfsd_file_lru); |
1214 | |
1215 | rcu_read_lock(); |
1216 | ht = &nfsd_file_rhltable.ht; |
1217 | count = atomic_read(v: &ht->nelems); |
1218 | tbl = rht_dereference_rcu(ht->tbl, ht); |
1219 | buckets = tbl->size; |
1220 | rcu_read_unlock(); |
1221 | } |
1222 | mutex_unlock(lock: &nfsd_mutex); |
1223 | |
1224 | for_each_possible_cpu(i) { |
1225 | hits += per_cpu(nfsd_file_cache_hits, i); |
1226 | acquisitions += per_cpu(nfsd_file_acquisitions, i); |
1227 | releases += per_cpu(nfsd_file_releases, i); |
1228 | total_age += per_cpu(nfsd_file_total_age, i); |
1229 | evictions += per_cpu(nfsd_file_evictions, i); |
1230 | } |
1231 | |
1232 | seq_printf(m, fmt: "total inodes: %u\n" , count); |
1233 | seq_printf(m, fmt: "hash buckets: %u\n" , buckets); |
1234 | seq_printf(m, fmt: "lru entries: %lu\n" , lru); |
1235 | seq_printf(m, fmt: "cache hits: %lu\n" , hits); |
1236 | seq_printf(m, fmt: "acquisitions: %lu\n" , acquisitions); |
1237 | seq_printf(m, fmt: "releases: %lu\n" , releases); |
1238 | seq_printf(m, fmt: "evictions: %lu\n" , evictions); |
1239 | if (releases) |
1240 | seq_printf(m, fmt: "mean age (ms): %ld\n" , total_age / releases); |
1241 | else |
1242 | seq_printf(m, fmt: "mean age (ms): -\n" ); |
1243 | return 0; |
1244 | } |
1245 | |