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(c1->fsuid, c2->fsuid))
83 return false;
84 if (!gid_eq(c1->fsgid, 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(c1->group_info->gid[i], 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(system_wq, &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(nf->nf_cred);
124 kmem_cache_free(nfsd_file_slab, 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(nfsd_file_mark_slab, 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(&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(&nfm->nfm_ref)) {
148 fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
149 fsnotify_put_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(nfsd_file_fsnotify_group);
162 mark = fsnotify_find_inode_mark(inode,
163 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(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, nfsd_file_fsnotify_group);
175 fsnotify_put_mark(mark);
176 } else {
177 fsnotify_group_unlock(nfsd_file_fsnotify_group);
178 }
179
180 /* allocate a new nfm */
181 new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
182 if (!new)
183 return NULL;
184 fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);
185 new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;
186 refcount_set(&new->nfm_ref, 1);
187
188 err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 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(&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(nfsd_file_slab, GFP_KERNEL);
215 if (unlikely(!nf))
216 return NULL;
217
218 INIT_LIST_HEAD(&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(&nf->nf_ref, 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(file->f_mapping, READ_ONCE(file->f_wb_err)))
247 nfsd_reset_write_verifier(net_generic(nf->nf_net, 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(&nfsd_file_rhltable, &nf->nf_rlist,
255 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, &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(nf->nf_mark);
281 if (nf->nf_file) {
282 nfsd_file_check_write_error(nf);
283 nfsd_filp_close(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(&nf->nf_rcu, 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(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, &nf->nf_flags);
322 if (list_lru_add_obj(&nfsd_file_lru, &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(&nfsd_file_lru, &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(&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(&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(&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(dispose)) {
396 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
397 list_del_init(&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(dispose)) {
413 struct nfsd_file *nf = list_first_entry(dispose,
414 struct nfsd_file, nf_lru);
415 struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id);
416 struct nfsd_fcache_disposal *l = nn->fcache_disposal;
417
418 spin_lock(&l->lock);
419 list_move_tail(&nf->nf_lru, &l->freeme);
420 spin_unlock(&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(&l->freeme)) {
439 LIST_HEAD(dispose);
440 int i;
441
442 spin_lock(&l->lock);
443 for (i = 0; i < 8 && !list_empty(&l->freeme); i++)
444 list_move(l->freeme.next, &dispose);
445 spin_unlock(&l->lock);
446 if (!list_empty(&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);
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, &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(&nf->nf_ref)) {
499 trace_nfsd_file_gc_in_use(nf);
500 list_lru_isolate(lru, &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(lru, &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(&nfsd_file_lru, nfsd_file_lru_cb,
519 &dispose, list_lru_count(&nfsd_file_lru));
520 trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru));
521 nfsd_file_dispose_list_delayed(&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(&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(&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(&nfsd_file_lru, sc,
545 nfsd_file_lru_cb, &dispose);
546 trace_nfsd_file_shrinker_removed(ret, list_lru_count(&nfsd_file_lru));
547 nfsd_file_dispose_list_delayed(&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(decrement, &nf->nf_ref)) {
581 list_add(&nf->nf_lru, 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(&nfsd_file_rhltable, &inode,
610 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);
634 nfsd_file_dispose_list_delayed(&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);
656 while (!list_empty(&dispose)) {
657 nf = list_first_entry(&dispose, struct nfsd_file, nf_lru);
658 list_del_init(&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_lease *fl = data;
668
669 /* Only close files for F_SETLEASE leases */
670 if (fl->c.flc_flags & FL_LEASE)
671 nfsd_file_close_inode(file_inode(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, &nfsd_file_flags) == 1)
718 return 0;
719
720 ret = rhltable_init(&nfsd_file_rhltable, &nfsd_file_rhash_params);
721 if (ret)
722 goto out;
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(0, "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(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(&nfsd_file_fsnotify_ops,
763 FSNOTIFY_GROUP_NOFS);
764 if (IS_ERR(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(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 if (ret)
775 clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags);
776 return ret;
777 out_notifier:
778 lease_unregister_notifier(&nfsd_file_lease_notifier);
779 out_shrinker:
780 shrinker_free(nfsd_file_shrinker);
781 out_lru:
782 list_lru_destroy(&nfsd_file_lru);
783 out_err:
784 kmem_cache_destroy(nfsd_file_slab);
785 nfsd_file_slab = NULL;
786 kmem_cache_destroy(nfsd_file_mark_slab);
787 nfsd_file_mark_slab = NULL;
788 rhltable_destroy(&nfsd_file_rhltable);
789 goto out;
790 }
791
792 /**
793 * __nfsd_file_cache_purge: clean out the cache for shutdown
794 * @net: net-namespace to shut down the cache (may be NULL)
795 *
796 * Walk the nfsd_file cache and close out any that match @net. If @net is NULL,
797 * then close out everything. Called when an nfsd instance is being shut down,
798 * and when the exports table is flushed.
799 */
800 static void
801 __nfsd_file_cache_purge(struct net *net)
802 {
803 struct rhashtable_iter iter;
804 struct nfsd_file *nf;
805 LIST_HEAD(dispose);
806
807 rhltable_walk_enter(&nfsd_file_rhltable, &iter);
808 do {
809 rhashtable_walk_start(&iter);
810
811 nf = rhashtable_walk_next(&iter);
812 while (!IS_ERR_OR_NULL(nf)) {
813 if (!net || nf->nf_net == net)
814 nfsd_file_cond_queue(nf, &dispose);
815 nf = rhashtable_walk_next(&iter);
816 }
817
818 rhashtable_walk_stop(&iter);
819 } while (nf == ERR_PTR(-EAGAIN));
820 rhashtable_walk_exit(&iter);
821
822 nfsd_file_dispose_list(&dispose);
823 }
824
825 static struct nfsd_fcache_disposal *
826 nfsd_alloc_fcache_disposal(void)
827 {
828 struct nfsd_fcache_disposal *l;
829
830 l = kmalloc(sizeof(*l), GFP_KERNEL);
831 if (!l)
832 return NULL;
833 spin_lock_init(&l->lock);
834 INIT_LIST_HEAD(&l->freeme);
835 return l;
836 }
837
838 static void
839 nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
840 {
841 nfsd_file_dispose_list(&l->freeme);
842 kfree(l);
843 }
844
845 static void
846 nfsd_free_fcache_disposal_net(struct net *net)
847 {
848 struct nfsd_net *nn = net_generic(net, nfsd_net_id);
849 struct nfsd_fcache_disposal *l = nn->fcache_disposal;
850
851 nfsd_free_fcache_disposal(l);
852 }
853
854 int
855 nfsd_file_cache_start_net(struct net *net)
856 {
857 struct nfsd_net *nn = net_generic(net, nfsd_net_id);
858
859 nn->fcache_disposal = nfsd_alloc_fcache_disposal();
860 return nn->fcache_disposal ? 0 : -ENOMEM;
861 }
862
863 /**
864 * nfsd_file_cache_purge - Remove all cache items associated with @net
865 * @net: target net namespace
866 *
867 */
868 void
869 nfsd_file_cache_purge(struct net *net)
870 {
871 lockdep_assert_held(&nfsd_mutex);
872 if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
873 __nfsd_file_cache_purge(net);
874 }
875
876 void
877 nfsd_file_cache_shutdown_net(struct net *net)
878 {
879 nfsd_file_cache_purge(net);
880 nfsd_free_fcache_disposal_net(net);
881 }
882
883 void
884 nfsd_file_cache_shutdown(void)
885 {
886 int i;
887
888 lockdep_assert_held(&nfsd_mutex);
889 if (test_and_clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0)
890 return;
891
892 lease_unregister_notifier(&nfsd_file_lease_notifier);
893 shrinker_free(nfsd_file_shrinker);
894 /*
895 * make sure all callers of nfsd_file_lru_cb are done before
896 * calling nfsd_file_cache_purge
897 */
898 cancel_delayed_work_sync(&nfsd_filecache_laundrette);
899 __nfsd_file_cache_purge(NULL);
900 list_lru_destroy(&nfsd_file_lru);
901 rcu_barrier();
902 fsnotify_put_group(nfsd_file_fsnotify_group);
903 nfsd_file_fsnotify_group = NULL;
904 kmem_cache_destroy(nfsd_file_slab);
905 nfsd_file_slab = NULL;
906 fsnotify_wait_marks_destroyed();
907 kmem_cache_destroy(nfsd_file_mark_slab);
908 nfsd_file_mark_slab = NULL;
909 rhltable_destroy(&nfsd_file_rhltable);
910
911 for_each_possible_cpu(i) {
912 per_cpu(nfsd_file_cache_hits, i) = 0;
913 per_cpu(nfsd_file_acquisitions, i) = 0;
914 per_cpu(nfsd_file_releases, i) = 0;
915 per_cpu(nfsd_file_total_age, i) = 0;
916 per_cpu(nfsd_file_evictions, i) = 0;
917 }
918 }
919
920 static struct nfsd_file *
921 nfsd_file_lookup_locked(const struct net *net, const struct cred *cred,
922 struct inode *inode, unsigned char need,
923 bool want_gc)
924 {
925 struct rhlist_head *tmp, *list;
926 struct nfsd_file *nf;
927
928 list = rhltable_lookup(&nfsd_file_rhltable, &inode,
929 nfsd_file_rhash_params);
930 rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) {
931 if (nf->nf_may != need)
932 continue;
933 if (nf->nf_net != net)
934 continue;
935 if (!nfsd_match_cred(nf->nf_cred, cred))
936 continue;
937 if (test_bit(NFSD_FILE_GC, &nf->nf_flags) != want_gc)
938 continue;
939 if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)
940 continue;
941
942 if (!nfsd_file_get(nf))
943 continue;
944 return nf;
945 }
946 return NULL;
947 }
948
949 /**
950 * nfsd_file_is_cached - are there any cached open files for this inode?
951 * @inode: inode to check
952 *
953 * The lookup matches inodes in all net namespaces and is atomic wrt
954 * nfsd_file_acquire().
955 *
956 * Return values:
957 * %true: filecache contains at least one file matching this inode
958 * %false: filecache contains no files matching this inode
959 */
960 bool
961 nfsd_file_is_cached(struct inode *inode)
962 {
963 struct rhlist_head *tmp, *list;
964 struct nfsd_file *nf;
965 bool ret = false;
966
967 rcu_read_lock();
968 list = rhltable_lookup(&nfsd_file_rhltable, &inode,
969 nfsd_file_rhash_params);
970 rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist)
971 if (test_bit(NFSD_FILE_GC, &nf->nf_flags)) {
972 ret = true;
973 break;
974 }
975 rcu_read_unlock();
976
977 trace_nfsd_file_is_cached(inode, (int)ret);
978 return ret;
979 }
980
981 static __be32
982 nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
983 unsigned int may_flags, struct file *file,
984 struct nfsd_file **pnf, bool want_gc)
985 {
986 unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
987 struct net *net = SVC_NET(rqstp);
988 struct nfsd_file *new, *nf;
989 bool stale_retry = true;
990 bool open_retry = true;
991 struct inode *inode;
992 __be32 status;
993 int ret;
994
995 retry:
996 status = fh_verify(rqstp, fhp, S_IFREG,
997 may_flags|NFSD_MAY_OWNER_OVERRIDE);
998 if (status != nfs_ok)
999 return status;
1000 inode = d_inode(fhp->fh_dentry);
1001
1002 rcu_read_lock();
1003 nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
1004 rcu_read_unlock();
1005
1006 if (nf) {
1007 /*
1008 * If the nf is on the LRU then it holds an extra reference
1009 * that must be put if it's removed. It had better not be
1010 * the last one however, since we should hold another.
1011 */
1012 if (nfsd_file_lru_remove(nf))
1013 WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref));
1014 goto wait_for_construction;
1015 }
1016
1017 new = nfsd_file_alloc(net, inode, need, want_gc);
1018 if (!new) {
1019 status = nfserr_jukebox;
1020 goto out;
1021 }
1022
1023 rcu_read_lock();
1024 spin_lock(&inode->i_lock);
1025 nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
1026 if (unlikely(nf)) {
1027 spin_unlock(&inode->i_lock);
1028 rcu_read_unlock();
1029 nfsd_file_slab_free(&new->nf_rcu);
1030 goto wait_for_construction;
1031 }
1032 nf = new;
1033 ret = rhltable_insert(&nfsd_file_rhltable, &nf->nf_rlist,
1034 nfsd_file_rhash_params);
1035 spin_unlock(&inode->i_lock);
1036 rcu_read_unlock();
1037 if (likely(ret == 0))
1038 goto open_file;
1039
1040 trace_nfsd_file_insert_err(rqstp, inode, may_flags, ret);
1041 status = nfserr_jukebox;
1042 goto construction_err;
1043
1044 wait_for_construction:
1045 wait_on_bit(&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 nfsd_file_put(nf);
1055 open_retry = false;
1056 fh_put(fhp);
1057 goto retry;
1058 }
1059 this_cpu_inc(nfsd_file_cache_hits);
1060
1061 status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags));
1062 if (status != nfs_ok) {
1063 nfsd_file_put(nf);
1064 nf = NULL;
1065 }
1066
1067 out:
1068 if (status == nfs_ok) {
1069 this_cpu_inc(nfsd_file_acquisitions);
1070 nfsd_file_check_write_error(nf);
1071 *pnf = nf;
1072 }
1073 trace_nfsd_file_acquire(rqstp, inode, may_flags, nf, status);
1074 return status;
1075
1076 open_file:
1077 trace_nfsd_file_alloc(nf);
1078 nf->nf_mark = nfsd_file_mark_find_or_create(nf, inode);
1079 if (nf->nf_mark) {
1080 if (file) {
1081 get_file(file);
1082 nf->nf_file = file;
1083 status = nfs_ok;
1084 trace_nfsd_file_opened(nf, status);
1085 } else {
1086 ret = nfsd_open_verified(rqstp, fhp, may_flags,
1087 &nf->nf_file);
1088 if (ret == -EOPENSTALE && stale_retry) {
1089 stale_retry = false;
1090 nfsd_file_unhash(nf);
1091 clear_and_wake_up_bit(NFSD_FILE_PENDING,
1092 &nf->nf_flags);
1093 if (refcount_dec_and_test(&nf->nf_ref))
1094 nfsd_file_free(nf);
1095 nf = NULL;
1096 fh_put(fhp);
1097 goto retry;
1098 }
1099 status = nfserrno(ret);
1100 trace_nfsd_file_open(nf, status);
1101 }
1102 } else
1103 status = nfserr_jukebox;
1104 /*
1105 * If construction failed, or we raced with a call to unlink()
1106 * then unhash.
1107 */
1108 if (status != nfs_ok || inode->i_nlink == 0)
1109 nfsd_file_unhash(nf);
1110 clear_and_wake_up_bit(NFSD_FILE_PENDING, &nf->nf_flags);
1111 if (status == nfs_ok)
1112 goto out;
1113
1114 construction_err:
1115 if (refcount_dec_and_test(&nf->nf_ref))
1116 nfsd_file_free(nf);
1117 nf = NULL;
1118 goto out;
1119 }
1120
1121 /**
1122 * nfsd_file_acquire_gc - Get a struct nfsd_file with an open file
1123 * @rqstp: the RPC transaction being executed
1124 * @fhp: the NFS filehandle of the file to be opened
1125 * @may_flags: NFSD_MAY_ settings for the file
1126 * @pnf: OUT: new or found "struct nfsd_file" object
1127 *
1128 * The nfsd_file object returned by this API is reference-counted
1129 * and garbage-collected. The object is retained for a few
1130 * seconds after the final nfsd_file_put() in case the caller
1131 * wants to re-use it.
1132 *
1133 * Return values:
1134 * %nfs_ok - @pnf points to an nfsd_file with its reference
1135 * count boosted.
1136 *
1137 * On error, an nfsstat value in network byte order is returned.
1138 */
1139 __be32
1140 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
1141 unsigned int may_flags, struct nfsd_file **pnf)
1142 {
1143 return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, true);
1144 }
1145
1146 /**
1147 * nfsd_file_acquire - Get a struct nfsd_file with an open file
1148 * @rqstp: the RPC transaction being executed
1149 * @fhp: the NFS filehandle of the file to be opened
1150 * @may_flags: NFSD_MAY_ settings for the file
1151 * @pnf: OUT: new or found "struct nfsd_file" object
1152 *
1153 * The nfsd_file_object returned by this API is reference-counted
1154 * but not garbage-collected. The object is unhashed after the
1155 * final nfsd_file_put().
1156 *
1157 * Return values:
1158 * %nfs_ok - @pnf points to an nfsd_file with its reference
1159 * count boosted.
1160 *
1161 * On error, an nfsstat value in network byte order is returned.
1162 */
1163 __be32
1164 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
1165 unsigned int may_flags, struct nfsd_file **pnf)
1166 {
1167 return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, false);
1168 }
1169
1170 /**
1171 * nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file
1172 * @rqstp: the RPC transaction being executed
1173 * @fhp: the NFS filehandle of the file just created
1174 * @may_flags: NFSD_MAY_ settings for the file
1175 * @file: cached, already-open file (may be NULL)
1176 * @pnf: OUT: new or found "struct nfsd_file" object
1177 *
1178 * Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist,
1179 * and @file is non-NULL, use it to instantiate a new nfsd_file instead of
1180 * opening a new one.
1181 *
1182 * Return values:
1183 * %nfs_ok - @pnf points to an nfsd_file with its reference
1184 * count boosted.
1185 *
1186 * On error, an nfsstat value in network byte order is returned.
1187 */
1188 __be32
1189 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
1190 unsigned int may_flags, struct file *file,
1191 struct nfsd_file **pnf)
1192 {
1193 return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, false);
1194 }
1195
1196 /*
1197 * Note that fields may be added, removed or reordered in the future. Programs
1198 * scraping this file for info should test the labels to ensure they're
1199 * getting the correct field.
1200 */
1201 int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
1202 {
1203 unsigned long releases = 0, evictions = 0;
1204 unsigned long hits = 0, acquisitions = 0;
1205 unsigned int i, count = 0, buckets = 0;
1206 unsigned long lru = 0, total_age = 0;
1207
1208 /* Serialize with server shutdown */
1209 mutex_lock(&nfsd_mutex);
1210 if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) {
1211 struct bucket_table *tbl;
1212 struct rhashtable *ht;
1213
1214 lru = list_lru_count(&nfsd_file_lru);
1215
1216 rcu_read_lock();
1217 ht = &nfsd_file_rhltable.ht;
1218 count = atomic_read(&ht->nelems);
1219 tbl = rht_dereference_rcu(ht->tbl, ht);
1220 buckets = tbl->size;
1221 rcu_read_unlock();
1222 }
1223 mutex_unlock(&nfsd_mutex);
1224
1225 for_each_possible_cpu(i) {
1226 hits += per_cpu(nfsd_file_cache_hits, i);
1227 acquisitions += per_cpu(nfsd_file_acquisitions, i);
1228 releases += per_cpu(nfsd_file_releases, i);
1229 total_age += per_cpu(nfsd_file_total_age, i);
1230 evictions += per_cpu(nfsd_file_evictions, i);
1231 }
1232
1233 seq_printf(m, "total inodes: %u\n", count);
1234 seq_printf(m, "hash buckets: %u\n", buckets);
1235 seq_printf(m, "lru entries: %lu\n", lru);
1236 seq_printf(m, "cache hits: %lu\n", hits);
1237 seq_printf(m, "acquisitions: %lu\n", acquisitions);
1238 seq_printf(m, "releases: %lu\n", releases);
1239 seq_printf(m, "evictions: %lu\n", evictions);
1240 if (releases)
1241 seq_printf(m, "mean age (ms): %ld\n", total_age / releases);
1242 else
1243 seq_printf(m, "mean age (ms): -\n");
1244 return 0;
1245 }
1246
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