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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
57static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
58static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions);
59static DEFINE_PER_CPU(unsigned long, nfsd_file_releases);
60static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age);
61static DEFINE_PER_CPU(unsigned long, nfsd_file_evictions);
62
63struct nfsd_fcache_disposal {
64 struct work_struct work;
65 spinlock_t lock;
66 struct list_head freeme;
67};
68
69static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
70
71static struct kmem_cache *nfsd_file_slab;
72static struct kmem_cache *nfsd_file_mark_slab;
73static struct list_lru nfsd_file_lru;
74static unsigned long nfsd_file_flags;
75static struct fsnotify_group *nfsd_file_fsnotify_group;
76static struct delayed_work nfsd_filecache_laundrette;
77static struct rhltable nfsd_file_rhltable
78 ____cacheline_aligned_in_smp;
79
80static bool
81nfsd_match_cred(const struct cred *c1, const struct cred *c2)
82{
83 int i;
84
85 if (!uid_eq(c1->fsuid, c2->fsuid))
86 return false;
87 if (!gid_eq(c1->fsgid, c2->fsgid))
88 return false;
89 if (c1->group_info == NULL || c2->group_info == NULL)
90 return c1->group_info == c2->group_info;
91 if (c1->group_info->ngroups != c2->group_info->ngroups)
92 return false;
93 for (i = 0; i < c1->group_info->ngroups; i++) {
94 if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
95 return false;
96 }
97 return true;
98}
99
100static const struct rhashtable_params nfsd_file_rhash_params = {
101 .key_len = sizeof_field(struct nfsd_file, nf_inode),
102 .key_offset = offsetof(struct nfsd_file, nf_inode),
103 .head_offset = offsetof(struct nfsd_file, nf_rlist),
104
105 /*
106 * Start with a single page hash table to reduce resizing churn
107 * on light workloads.
108 */
109 .min_size = 256,
110 .automatic_shrinking = true,
111};
112
113static void
114nfsd_file_schedule_laundrette(void)
115{
116 if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags))
117 queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
118 NFSD_LAUNDRETTE_DELAY);
119}
120
121static void
122nfsd_file_slab_free(struct rcu_head *rcu)
123{
124 struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
125
126 put_cred(nf->nf_cred);
127 kmem_cache_free(nfsd_file_slab, nf);
128}
129
130static void
131nfsd_file_mark_free(struct fsnotify_mark *mark)
132{
133 struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
134 nfm_mark);
135
136 kmem_cache_free(nfsd_file_mark_slab, nfm);
137}
138
139static struct nfsd_file_mark *
140nfsd_file_mark_get(struct nfsd_file_mark *nfm)
141{
142 if (!refcount_inc_not_zero(&nfm->nfm_ref))
143 return NULL;
144 return nfm;
145}
146
147static void
148nfsd_file_mark_put(struct nfsd_file_mark *nfm)
149{
150 if (refcount_dec_and_test(&nfm->nfm_ref)) {
151 fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
152 fsnotify_put_mark(&nfm->nfm_mark);
153 }
154}
155
156static struct nfsd_file_mark *
157nfsd_file_mark_find_or_create(struct nfsd_file *nf, struct inode *inode)
158{
159 int err;
160 struct fsnotify_mark *mark;
161 struct nfsd_file_mark *nfm = NULL, *new;
162
163 do {
164 fsnotify_group_lock(nfsd_file_fsnotify_group);
165 mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
166 nfsd_file_fsnotify_group);
167 if (mark) {
168 nfm = nfsd_file_mark_get(container_of(mark,
169 struct nfsd_file_mark,
170 nfm_mark));
171 fsnotify_group_unlock(nfsd_file_fsnotify_group);
172 if (nfm) {
173 fsnotify_put_mark(mark);
174 break;
175 }
176 /* Avoid soft lockup race with nfsd_file_mark_put() */
177 fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
178 fsnotify_put_mark(mark);
179 } else {
180 fsnotify_group_unlock(nfsd_file_fsnotify_group);
181 }
182
183 /* allocate a new nfm */
184 new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
185 if (!new)
186 return NULL;
187 fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);
188 new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;
189 refcount_set(&new->nfm_ref, 1);
190
191 err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0);
192
193 /*
194 * If the add was successful, then return the object.
195 * Otherwise, we need to put the reference we hold on the
196 * nfm_mark. The fsnotify code will take a reference and put
197 * it on failure, so we can't just free it directly. It's also
198 * not safe to call fsnotify_destroy_mark on it as the
199 * mark->group will be NULL. Thus, we can't let the nfm_ref
200 * counter drive the destruction at this point.
201 */
202 if (likely(!err))
203 nfm = new;
204 else
205 fsnotify_put_mark(&new->nfm_mark);
206 } while (unlikely(err == -EEXIST));
207
208 return nfm;
209}
210
211static struct nfsd_file *
212nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need,
213 bool want_gc)
214{
215 struct nfsd_file *nf;
216
217 nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
218 if (unlikely(!nf))
219 return NULL;
220
221 INIT_LIST_HEAD(&nf->nf_lru);
222 nf->nf_birthtime = ktime_get();
223 nf->nf_file = NULL;
224 nf->nf_cred = get_current_cred();
225 nf->nf_net = net;
226 nf->nf_flags = want_gc ?
227 BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING) | BIT(NFSD_FILE_GC) :
228 BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING);
229 nf->nf_inode = inode;
230 refcount_set(&nf->nf_ref, 1);
231 nf->nf_may = need;
232 nf->nf_mark = NULL;
233 return nf;
234}
235
236/**
237 * nfsd_file_check_write_error - check for writeback errors on a file
238 * @nf: nfsd_file to check for writeback errors
239 *
240 * Check whether a nfsd_file has an unseen error. Reset the write
241 * verifier if so.
242 */
243static void
244nfsd_file_check_write_error(struct nfsd_file *nf)
245{
246 struct file *file = nf->nf_file;
247
248 if ((file->f_mode & FMODE_WRITE) &&
249 filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err)))
250 nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
251}
252
253static void
254nfsd_file_hash_remove(struct nfsd_file *nf)
255{
256 trace_nfsd_file_unhash(nf);
257 rhltable_remove(&nfsd_file_rhltable, &nf->nf_rlist,
258 nfsd_file_rhash_params);
259}
260
261static bool
262nfsd_file_unhash(struct nfsd_file *nf)
263{
264 if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
265 nfsd_file_hash_remove(nf);
266 return true;
267 }
268 return false;
269}
270
271static void
272nfsd_file_free(struct nfsd_file *nf)
273{
274 s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime));
275
276 trace_nfsd_file_free(nf);
277
278 this_cpu_inc(nfsd_file_releases);
279 this_cpu_add(nfsd_file_total_age, age);
280
281 nfsd_file_unhash(nf);
282 if (nf->nf_mark)
283 nfsd_file_mark_put(nf->nf_mark);
284 if (nf->nf_file) {
285 nfsd_file_check_write_error(nf);
286 filp_close(nf->nf_file, NULL);
287 }
288
289 /*
290 * If this item is still linked via nf_lru, that's a bug.
291 * WARN and leak it to preserve system stability.
292 */
293 if (WARN_ON_ONCE(!list_empty(&nf->nf_lru)))
294 return;
295
296 call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
297}
298
299static bool
300nfsd_file_check_writeback(struct nfsd_file *nf)
301{
302 struct file *file = nf->nf_file;
303 struct address_space *mapping;
304
305 /* File not open for write? */
306 if (!(file->f_mode & FMODE_WRITE))
307 return false;
308
309 /*
310 * Some filesystems (e.g. NFS) flush all dirty data on close.
311 * On others, there is no need to wait for writeback.
312 */
313 if (!(file_inode(file)->i_sb->s_export_op->flags & EXPORT_OP_FLUSH_ON_CLOSE))
314 return false;
315
316 mapping = file->f_mapping;
317 return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
318 mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
319}
320
321
322static bool nfsd_file_lru_add(struct nfsd_file *nf)
323{
324 set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
325 if (list_lru_add_obj(&nfsd_file_lru, &nf->nf_lru)) {
326 trace_nfsd_file_lru_add(nf);
327 return true;
328 }
329 return false;
330}
331
332static bool nfsd_file_lru_remove(struct nfsd_file *nf)
333{
334 if (list_lru_del_obj(&nfsd_file_lru, &nf->nf_lru)) {
335 trace_nfsd_file_lru_del(nf);
336 return true;
337 }
338 return false;
339}
340
341struct nfsd_file *
342nfsd_file_get(struct nfsd_file *nf)
343{
344 if (nf && refcount_inc_not_zero(&nf->nf_ref))
345 return nf;
346 return NULL;
347}
348
349/**
350 * nfsd_file_put - put the reference to a nfsd_file
351 * @nf: nfsd_file of which to put the reference
352 *
353 * Put a reference to a nfsd_file. In the non-GC case, we just put the
354 * reference immediately. In the GC case, if the reference would be
355 * the last one, the put it on the LRU instead to be cleaned up later.
356 */
357void
358nfsd_file_put(struct nfsd_file *nf)
359{
360 might_sleep();
361 trace_nfsd_file_put(nf);
362
363 if (test_bit(NFSD_FILE_GC, &nf->nf_flags) &&
364 test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
365 /*
366 * If this is the last reference (nf_ref == 1), then try to
367 * transfer it to the LRU.
368 */
369 if (refcount_dec_not_one(&nf->nf_ref))
370 return;
371
372 /* Try to add it to the LRU. If that fails, decrement. */
373 if (nfsd_file_lru_add(nf)) {
374 /* If it's still hashed, we're done */
375 if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
376 nfsd_file_schedule_laundrette();
377 return;
378 }
379
380 /*
381 * We're racing with unhashing, so try to remove it from
382 * the LRU. If removal fails, then someone else already
383 * has our reference.
384 */
385 if (!nfsd_file_lru_remove(nf))
386 return;
387 }
388 }
389 if (refcount_dec_and_test(&nf->nf_ref))
390 nfsd_file_free(nf);
391}
392
393static void
394nfsd_file_dispose_list(struct list_head *dispose)
395{
396 struct nfsd_file *nf;
397
398 while (!list_empty(dispose)) {
399 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
400 list_del_init(&nf->nf_lru);
401 nfsd_file_free(nf);
402 }
403}
404
405/**
406 * nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list
407 * @dispose: list of nfsd_files to be disposed
408 *
409 * Transfers each file to the "freeme" list for its nfsd_net, to eventually
410 * be disposed of by the per-net garbage collector.
411 */
412static void
413nfsd_file_dispose_list_delayed(struct list_head *dispose)
414{
415 while(!list_empty(dispose)) {
416 struct nfsd_file *nf = list_first_entry(dispose,
417 struct nfsd_file, nf_lru);
418 struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id);
419 struct nfsd_fcache_disposal *l = nn->fcache_disposal;
420
421 spin_lock(&l->lock);
422 list_move_tail(&nf->nf_lru, &l->freeme);
423 spin_unlock(&l->lock);
424 queue_work(nfsd_filecache_wq, &l->work);
425 }
426}
427
428/**
429 * nfsd_file_lru_cb - Examine an entry on the LRU list
430 * @item: LRU entry to examine
431 * @lru: controlling LRU
432 * @lock: LRU list lock (unused)
433 * @arg: dispose list
434 *
435 * Return values:
436 * %LRU_REMOVED: @item was removed from the LRU
437 * %LRU_ROTATE: @item is to be moved to the LRU tail
438 * %LRU_SKIP: @item cannot be evicted
439 */
440static enum lru_status
441nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
442 spinlock_t *lock, void *arg)
443 __releases(lock)
444 __acquires(lock)
445{
446 struct list_head *head = arg;
447 struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru);
448
449 /* We should only be dealing with GC entries here */
450 WARN_ON_ONCE(!test_bit(NFSD_FILE_GC, &nf->nf_flags));
451
452 /*
453 * Don't throw out files that are still undergoing I/O or
454 * that have uncleared errors pending.
455 */
456 if (nfsd_file_check_writeback(nf)) {
457 trace_nfsd_file_gc_writeback(nf);
458 return LRU_SKIP;
459 }
460
461 /* If it was recently added to the list, skip it */
462 if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) {
463 trace_nfsd_file_gc_referenced(nf);
464 return LRU_ROTATE;
465 }
466
467 /*
468 * Put the reference held on behalf of the LRU. If it wasn't the last
469 * one, then just remove it from the LRU and ignore it.
470 */
471 if (!refcount_dec_and_test(&nf->nf_ref)) {
472 trace_nfsd_file_gc_in_use(nf);
473 list_lru_isolate(lru, &nf->nf_lru);
474 return LRU_REMOVED;
475 }
476
477 /* Refcount went to zero. Unhash it and queue it to the dispose list */
478 nfsd_file_unhash(nf);
479 list_lru_isolate_move(lru, &nf->nf_lru, head);
480 this_cpu_inc(nfsd_file_evictions);
481 trace_nfsd_file_gc_disposed(nf);
482 return LRU_REMOVED;
483}
484
485static void
486nfsd_file_gc(void)
487{
488 LIST_HEAD(dispose);
489 unsigned long ret;
490
491 ret = list_lru_walk(&nfsd_file_lru, nfsd_file_lru_cb,
492 &dispose, list_lru_count(&nfsd_file_lru));
493 trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru));
494 nfsd_file_dispose_list_delayed(&dispose);
495}
496
497static void
498nfsd_file_gc_worker(struct work_struct *work)
499{
500 nfsd_file_gc();
501 if (list_lru_count(&nfsd_file_lru))
502 nfsd_file_schedule_laundrette();
503}
504
505static unsigned long
506nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc)
507{
508 return list_lru_count(&nfsd_file_lru);
509}
510
511static unsigned long
512nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc)
513{
514 LIST_HEAD(dispose);
515 unsigned long ret;
516
517 ret = list_lru_shrink_walk(&nfsd_file_lru, sc,
518 nfsd_file_lru_cb, &dispose);
519 trace_nfsd_file_shrinker_removed(ret, list_lru_count(&nfsd_file_lru));
520 nfsd_file_dispose_list_delayed(&dispose);
521 return ret;
522}
523
524static struct shrinker *nfsd_file_shrinker;
525
526/**
527 * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file
528 * @nf: nfsd_file to attempt to queue
529 * @dispose: private list to queue successfully-put objects
530 *
531 * Unhash an nfsd_file, try to get a reference to it, and then put that
532 * reference. If it's the last reference, queue it to the dispose list.
533 */
534static void
535nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose)
536 __must_hold(RCU)
537{
538 int decrement = 1;
539
540 /* If we raced with someone else unhashing, ignore it */
541 if (!nfsd_file_unhash(nf))
542 return;
543
544 /* If we can't get a reference, ignore it */
545 if (!nfsd_file_get(nf))
546 return;
547
548 /* Extra decrement if we remove from the LRU */
549 if (nfsd_file_lru_remove(nf))
550 ++decrement;
551
552 /* If refcount goes to 0, then put on the dispose list */
553 if (refcount_sub_and_test(decrement, &nf->nf_ref)) {
554 list_add(&nf->nf_lru, dispose);
555 trace_nfsd_file_closing(nf);
556 }
557}
558
559/**
560 * nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode
561 * @inode: inode on which to close out nfsd_files
562 * @dispose: list on which to gather nfsd_files to close out
563 *
564 * An nfsd_file represents a struct file being held open on behalf of nfsd.
565 * An open file however can block other activity (such as leases), or cause
566 * undesirable behavior (e.g. spurious silly-renames when reexporting NFS).
567 *
568 * This function is intended to find open nfsd_files when this sort of
569 * conflicting access occurs and then attempt to close those files out.
570 *
571 * Populates the dispose list with entries that have already had their
572 * refcounts go to zero. The actual free of an nfsd_file can be expensive,
573 * so we leave it up to the caller whether it wants to wait or not.
574 */
575static void
576nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose)
577{
578 struct rhlist_head *tmp, *list;
579 struct nfsd_file *nf;
580
581 rcu_read_lock();
582 list = rhltable_lookup(&nfsd_file_rhltable, &inode,
583 nfsd_file_rhash_params);
584 rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) {
585 if (!test_bit(NFSD_FILE_GC, &nf->nf_flags))
586 continue;
587 nfsd_file_cond_queue(nf, dispose);
588 }
589 rcu_read_unlock();
590}
591
592/**
593 * nfsd_file_close_inode - attempt a delayed close of a nfsd_file
594 * @inode: inode of the file to attempt to remove
595 *
596 * Close out any open nfsd_files that can be reaped for @inode. The
597 * actual freeing is deferred to the dispose_list_delayed infrastructure.
598 *
599 * This is used by the fsnotify callbacks and setlease notifier.
600 */
601static void
602nfsd_file_close_inode(struct inode *inode)
603{
604 LIST_HEAD(dispose);
605
606 nfsd_file_queue_for_close(inode, &dispose);
607 nfsd_file_dispose_list_delayed(&dispose);
608}
609
610/**
611 * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
612 * @inode: inode of the file to attempt to remove
613 *
614 * Close out any open nfsd_files that can be reaped for @inode. The
615 * nfsd_files are closed out synchronously.
616 *
617 * This is called from nfsd_rename and nfsd_unlink to avoid silly-renames
618 * when reexporting NFS.
619 */
620void
621nfsd_file_close_inode_sync(struct inode *inode)
622{
623 struct nfsd_file *nf;
624 LIST_HEAD(dispose);
625
626 trace_nfsd_file_close(inode);
627
628 nfsd_file_queue_for_close(inode, &dispose);
629 while (!list_empty(&dispose)) {
630 nf = list_first_entry(&dispose, struct nfsd_file, nf_lru);
631 list_del_init(&nf->nf_lru);
632 nfsd_file_free(nf);
633 }
634 flush_delayed_fput();
635}
636
637/**
638 * nfsd_file_delayed_close - close unused nfsd_files
639 * @work: dummy
640 *
641 * Scrape the freeme list for this nfsd_net, and then dispose of them
642 * all.
643 */
644static void
645nfsd_file_delayed_close(struct work_struct *work)
646{
647 LIST_HEAD(head);
648 struct nfsd_fcache_disposal *l = container_of(work,
649 struct nfsd_fcache_disposal, work);
650
651 spin_lock(&l->lock);
652 list_splice_init(&l->freeme, &head);
653 spin_unlock(&l->lock);
654
655 nfsd_file_dispose_list(&head);
656}
657
658static int
659nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg,
660 void *data)
661{
662 struct file_lock *fl = data;
663
664 /* Only close files for F_SETLEASE leases */
665 if (fl->fl_flags & FL_LEASE)
666 nfsd_file_close_inode(file_inode(fl->fl_file));
667 return 0;
668}
669
670static struct notifier_block nfsd_file_lease_notifier = {
671 .notifier_call = nfsd_file_lease_notifier_call,
672};
673
674static int
675nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask,
676 struct inode *inode, struct inode *dir,
677 const struct qstr *name, u32 cookie)
678{
679 if (WARN_ON_ONCE(!inode))
680 return 0;
681
682 trace_nfsd_file_fsnotify_handle_event(inode, mask);
683
684 /* Should be no marks on non-regular files */
685 if (!S_ISREG(inode->i_mode)) {
686 WARN_ON_ONCE(1);
687 return 0;
688 }
689
690 /* don't close files if this was not the last link */
691 if (mask & FS_ATTRIB) {
692 if (inode->i_nlink)
693 return 0;
694 }
695
696 nfsd_file_close_inode(inode);
697 return 0;
698}
699
700
701static const struct fsnotify_ops nfsd_file_fsnotify_ops = {
702 .handle_inode_event = nfsd_file_fsnotify_handle_event,
703 .free_mark = nfsd_file_mark_free,
704};
705
706int
707nfsd_file_cache_init(void)
708{
709 int ret;
710
711 lockdep_assert_held(&nfsd_mutex);
712 if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
713 return 0;
714
715 ret = rhltable_init(&nfsd_file_rhltable, &nfsd_file_rhash_params);
716 if (ret)
717 return ret;
718
719 ret = -ENOMEM;
720 nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", WQ_UNBOUND, 0);
721 if (!nfsd_filecache_wq)
722 goto out;
723
724 nfsd_file_slab = kmem_cache_create("nfsd_file",
725 sizeof(struct nfsd_file), 0, 0, NULL);
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_create("nfsd_file_mark",
732 sizeof(struct nfsd_file_mark), 0, 0, NULL);
733 if (!nfsd_file_mark_slab) {
734 pr_err("nfsd: unable to create nfsd_file_mark_slab\n");
735 goto out_err;
736 }
737
738
739 ret = list_lru_init(&nfsd_file_lru);
740 if (ret) {
741 pr_err("nfsd: failed to init nfsd_file_lru: %d\n", ret);
742 goto out_err;
743 }
744
745 nfsd_file_shrinker = shrinker_alloc(0, "nfsd-filecache");
746 if (!nfsd_file_shrinker) {
747 ret = -ENOMEM;
748 pr_err("nfsd: failed to allocate nfsd_file_shrinker\n");
749 goto out_lru;
750 }
751
752 nfsd_file_shrinker->count_objects = nfsd_file_lru_count;
753 nfsd_file_shrinker->scan_objects = nfsd_file_lru_scan;
754 nfsd_file_shrinker->seeks = 1;
755
756 shrinker_register(nfsd_file_shrinker);
757
758 ret = lease_register_notifier(&nfsd_file_lease_notifier);
759 if (ret) {
760 pr_err("nfsd: unable to register lease notifier: %d\n", ret);
761 goto out_shrinker;
762 }
763
764 nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops,
765 FSNOTIFY_GROUP_NOFS);
766 if (IS_ERR(nfsd_file_fsnotify_group)) {
767 pr_err("nfsd: unable to create fsnotify group: %ld\n",
768 PTR_ERR(nfsd_file_fsnotify_group));
769 ret = PTR_ERR(nfsd_file_fsnotify_group);
770 nfsd_file_fsnotify_group = NULL;
771 goto out_notifier;
772 }
773
774 INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker);
775out:
776 return ret;
777out_notifier:
778 lease_unregister_notifier(&nfsd_file_lease_notifier);
779out_shrinker:
780 shrinker_free(nfsd_file_shrinker);
781out_lru:
782 list_lru_destroy(&nfsd_file_lru);
783out_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 destroy_workqueue(nfsd_filecache_wq);
789 nfsd_filecache_wq = NULL;
790 rhltable_destroy(&nfsd_file_rhltable);
791 goto out;
792}
793
794/**
795 * __nfsd_file_cache_purge: clean out the cache for shutdown
796 * @net: net-namespace to shut down the cache (may be NULL)
797 *
798 * Walk the nfsd_file cache and close out any that match @net. If @net is NULL,
799 * then close out everything. Called when an nfsd instance is being shut down,
800 * and when the exports table is flushed.
801 */
802static void
803__nfsd_file_cache_purge(struct net *net)
804{
805 struct rhashtable_iter iter;
806 struct nfsd_file *nf;
807 LIST_HEAD(dispose);
808
809 rhltable_walk_enter(&nfsd_file_rhltable, &iter);
810 do {
811 rhashtable_walk_start(&iter);
812
813 nf = rhashtable_walk_next(&iter);
814 while (!IS_ERR_OR_NULL(nf)) {
815 if (!net || nf->nf_net == net)
816 nfsd_file_cond_queue(nf, &dispose);
817 nf = rhashtable_walk_next(&iter);
818 }
819
820 rhashtable_walk_stop(&iter);
821 } while (nf == ERR_PTR(-EAGAIN));
822 rhashtable_walk_exit(&iter);
823
824 nfsd_file_dispose_list(&dispose);
825}
826
827static struct nfsd_fcache_disposal *
828nfsd_alloc_fcache_disposal(void)
829{
830 struct nfsd_fcache_disposal *l;
831
832 l = kmalloc(sizeof(*l), GFP_KERNEL);
833 if (!l)
834 return NULL;
835 INIT_WORK(&l->work, nfsd_file_delayed_close);
836 spin_lock_init(&l->lock);
837 INIT_LIST_HEAD(&l->freeme);
838 return l;
839}
840
841static void
842nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
843{
844 cancel_work_sync(&l->work);
845 nfsd_file_dispose_list(&l->freeme);
846 kfree(l);
847}
848
849static void
850nfsd_free_fcache_disposal_net(struct net *net)
851{
852 struct nfsd_net *nn = net_generic(net, nfsd_net_id);
853 struct nfsd_fcache_disposal *l = nn->fcache_disposal;
854
855 nfsd_free_fcache_disposal(l);
856}
857
858int
859nfsd_file_cache_start_net(struct net *net)
860{
861 struct nfsd_net *nn = net_generic(net, nfsd_net_id);
862
863 nn->fcache_disposal = nfsd_alloc_fcache_disposal();
864 return nn->fcache_disposal ? 0 : -ENOMEM;
865}
866
867/**
868 * nfsd_file_cache_purge - Remove all cache items associated with @net
869 * @net: target net namespace
870 *
871 */
872void
873nfsd_file_cache_purge(struct net *net)
874{
875 lockdep_assert_held(&nfsd_mutex);
876 if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
877 __nfsd_file_cache_purge(net);
878}
879
880void
881nfsd_file_cache_shutdown_net(struct net *net)
882{
883 nfsd_file_cache_purge(net);
884 nfsd_free_fcache_disposal_net(net);
885}
886
887void
888nfsd_file_cache_shutdown(void)
889{
890 int i;
891
892 lockdep_assert_held(&nfsd_mutex);
893 if (test_and_clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0)
894 return;
895
896 lease_unregister_notifier(&nfsd_file_lease_notifier);
897 shrinker_free(nfsd_file_shrinker);
898 /*
899 * make sure all callers of nfsd_file_lru_cb are done before
900 * calling nfsd_file_cache_purge
901 */
902 cancel_delayed_work_sync(&nfsd_filecache_laundrette);
903 __nfsd_file_cache_purge(NULL);
904 list_lru_destroy(&nfsd_file_lru);
905 rcu_barrier();
906 fsnotify_put_group(nfsd_file_fsnotify_group);
907 nfsd_file_fsnotify_group = NULL;
908 kmem_cache_destroy(nfsd_file_slab);
909 nfsd_file_slab = NULL;
910 fsnotify_wait_marks_destroyed();
911 kmem_cache_destroy(nfsd_file_mark_slab);
912 nfsd_file_mark_slab = NULL;
913 destroy_workqueue(nfsd_filecache_wq);
914 nfsd_filecache_wq = NULL;
915 rhltable_destroy(&nfsd_file_rhltable);
916
917 for_each_possible_cpu(i) {
918 per_cpu(nfsd_file_cache_hits, i) = 0;
919 per_cpu(nfsd_file_acquisitions, i) = 0;
920 per_cpu(nfsd_file_releases, i) = 0;
921 per_cpu(nfsd_file_total_age, i) = 0;
922 per_cpu(nfsd_file_evictions, i) = 0;
923 }
924}
925
926static struct nfsd_file *
927nfsd_file_lookup_locked(const struct net *net, const struct cred *cred,
928 struct inode *inode, unsigned char need,
929 bool want_gc)
930{
931 struct rhlist_head *tmp, *list;
932 struct nfsd_file *nf;
933
934 list = rhltable_lookup(&nfsd_file_rhltable, &inode,
935 nfsd_file_rhash_params);
936 rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) {
937 if (nf->nf_may != need)
938 continue;
939 if (nf->nf_net != net)
940 continue;
941 if (!nfsd_match_cred(nf->nf_cred, cred))
942 continue;
943 if (test_bit(NFSD_FILE_GC, &nf->nf_flags) != want_gc)
944 continue;
945 if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)
946 continue;
947
948 if (!nfsd_file_get(nf))
949 continue;
950 return nf;
951 }
952 return NULL;
953}
954
955/**
956 * nfsd_file_is_cached - are there any cached open files for this inode?
957 * @inode: inode to check
958 *
959 * The lookup matches inodes in all net namespaces and is atomic wrt
960 * nfsd_file_acquire().
961 *
962 * Return values:
963 * %true: filecache contains at least one file matching this inode
964 * %false: filecache contains no files matching this inode
965 */
966bool
967nfsd_file_is_cached(struct inode *inode)
968{
969 struct rhlist_head *tmp, *list;
970 struct nfsd_file *nf;
971 bool ret = false;
972
973 rcu_read_lock();
974 list = rhltable_lookup(&nfsd_file_rhltable, &inode,
975 nfsd_file_rhash_params);
976 rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist)
977 if (test_bit(NFSD_FILE_GC, &nf->nf_flags)) {
978 ret = true;
979 break;
980 }
981 rcu_read_unlock();
982
983 trace_nfsd_file_is_cached(inode, (int)ret);
984 return ret;
985}
986
987static __be32
988nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
989 unsigned int may_flags, struct file *file,
990 struct nfsd_file **pnf, bool want_gc)
991{
992 unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
993 struct net *net = SVC_NET(rqstp);
994 struct nfsd_file *new, *nf;
995 bool stale_retry = true;
996 bool open_retry = true;
997 struct inode *inode;
998 __be32 status;
999 int ret;
1000
1001retry:
1002 status = fh_verify(rqstp, fhp, S_IFREG,
1003 may_flags|NFSD_MAY_OWNER_OVERRIDE);
1004 if (status != nfs_ok)
1005 return status;
1006 inode = d_inode(fhp->fh_dentry);
1007
1008 rcu_read_lock();
1009 nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
1010 rcu_read_unlock();
1011
1012 if (nf) {
1013 /*
1014 * If the nf is on the LRU then it holds an extra reference
1015 * that must be put if it's removed. It had better not be
1016 * the last one however, since we should hold another.
1017 */
1018 if (nfsd_file_lru_remove(nf))
1019 WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref));
1020 goto wait_for_construction;
1021 }
1022
1023 new = nfsd_file_alloc(net, inode, need, want_gc);
1024 if (!new) {
1025 status = nfserr_jukebox;
1026 goto out;
1027 }
1028
1029 rcu_read_lock();
1030 spin_lock(&inode->i_lock);
1031 nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
1032 if (unlikely(nf)) {
1033 spin_unlock(&inode->i_lock);
1034 rcu_read_unlock();
1035 nfsd_file_slab_free(&new->nf_rcu);
1036 goto wait_for_construction;
1037 }
1038 nf = new;
1039 ret = rhltable_insert(&nfsd_file_rhltable, &nf->nf_rlist,
1040 nfsd_file_rhash_params);
1041 spin_unlock(&inode->i_lock);
1042 rcu_read_unlock();
1043 if (likely(ret == 0))
1044 goto open_file;
1045
1046 if (ret == -EEXIST)
1047 goto retry;
1048 trace_nfsd_file_insert_err(rqstp, inode, may_flags, ret);
1049 status = nfserr_jukebox;
1050 goto construction_err;
1051
1052wait_for_construction:
1053 wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE);
1054
1055 /* Did construction of this file fail? */
1056 if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
1057 trace_nfsd_file_cons_err(rqstp, inode, may_flags, nf);
1058 if (!open_retry) {
1059 status = nfserr_jukebox;
1060 goto construction_err;
1061 }
1062 open_retry = false;
1063 fh_put(fhp);
1064 goto retry;
1065 }
1066 this_cpu_inc(nfsd_file_cache_hits);
1067
1068 status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags));
1069 if (status != nfs_ok) {
1070 nfsd_file_put(nf);
1071 nf = NULL;
1072 }
1073
1074out:
1075 if (status == nfs_ok) {
1076 this_cpu_inc(nfsd_file_acquisitions);
1077 nfsd_file_check_write_error(nf);
1078 *pnf = nf;
1079 }
1080 trace_nfsd_file_acquire(rqstp, inode, may_flags, nf, status);
1081 return status;
1082
1083open_file:
1084 trace_nfsd_file_alloc(nf);
1085 nf->nf_mark = nfsd_file_mark_find_or_create(nf, inode);
1086 if (nf->nf_mark) {
1087 if (file) {
1088 get_file(file);
1089 nf->nf_file = file;
1090 status = nfs_ok;
1091 trace_nfsd_file_opened(nf, status);
1092 } else {
1093 ret = nfsd_open_verified(rqstp, fhp, may_flags,
1094 &nf->nf_file);
1095 if (ret == -EOPENSTALE && stale_retry) {
1096 stale_retry = false;
1097 nfsd_file_unhash(nf);
1098 clear_and_wake_up_bit(NFSD_FILE_PENDING,
1099 &nf->nf_flags);
1100 if (refcount_dec_and_test(&nf->nf_ref))
1101 nfsd_file_free(nf);
1102 nf = NULL;
1103 fh_put(fhp);
1104 goto retry;
1105 }
1106 status = nfserrno(ret);
1107 trace_nfsd_file_open(nf, status);
1108 }
1109 } else
1110 status = nfserr_jukebox;
1111 /*
1112 * If construction failed, or we raced with a call to unlink()
1113 * then unhash.
1114 */
1115 if (status != nfs_ok || inode->i_nlink == 0)
1116 nfsd_file_unhash(nf);
1117 clear_and_wake_up_bit(NFSD_FILE_PENDING, &nf->nf_flags);
1118 if (status == nfs_ok)
1119 goto out;
1120
1121construction_err:
1122 if (refcount_dec_and_test(&nf->nf_ref))
1123 nfsd_file_free(nf);
1124 nf = NULL;
1125 goto out;
1126}
1127
1128/**
1129 * nfsd_file_acquire_gc - Get a struct nfsd_file with an open file
1130 * @rqstp: the RPC transaction being executed
1131 * @fhp: the NFS filehandle of the file to be opened
1132 * @may_flags: NFSD_MAY_ settings for the file
1133 * @pnf: OUT: new or found "struct nfsd_file" object
1134 *
1135 * The nfsd_file object returned by this API is reference-counted
1136 * and garbage-collected. The object is retained for a few
1137 * seconds after the final nfsd_file_put() in case the caller
1138 * wants to re-use it.
1139 *
1140 * Return values:
1141 * %nfs_ok - @pnf points to an nfsd_file with its reference
1142 * count boosted.
1143 *
1144 * On error, an nfsstat value in network byte order is returned.
1145 */
1146__be32
1147nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
1148 unsigned int may_flags, struct nfsd_file **pnf)
1149{
1150 return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, true);
1151}
1152
1153/**
1154 * nfsd_file_acquire - Get a struct nfsd_file with an open file
1155 * @rqstp: the RPC transaction being executed
1156 * @fhp: the NFS filehandle of the file to be opened
1157 * @may_flags: NFSD_MAY_ settings for the file
1158 * @pnf: OUT: new or found "struct nfsd_file" object
1159 *
1160 * The nfsd_file_object returned by this API is reference-counted
1161 * but not garbage-collected. The object is unhashed after the
1162 * final nfsd_file_put().
1163 *
1164 * Return values:
1165 * %nfs_ok - @pnf points to an nfsd_file with its reference
1166 * count boosted.
1167 *
1168 * On error, an nfsstat value in network byte order is returned.
1169 */
1170__be32
1171nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
1172 unsigned int may_flags, struct nfsd_file **pnf)
1173{
1174 return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, false);
1175}
1176
1177/**
1178 * nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file
1179 * @rqstp: the RPC transaction being executed
1180 * @fhp: the NFS filehandle of the file just created
1181 * @may_flags: NFSD_MAY_ settings for the file
1182 * @file: cached, already-open file (may be NULL)
1183 * @pnf: OUT: new or found "struct nfsd_file" object
1184 *
1185 * Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist,
1186 * and @file is non-NULL, use it to instantiate a new nfsd_file instead of
1187 * opening a new one.
1188 *
1189 * Return values:
1190 * %nfs_ok - @pnf points to an nfsd_file with its reference
1191 * count boosted.
1192 *
1193 * On error, an nfsstat value in network byte order is returned.
1194 */
1195__be32
1196nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
1197 unsigned int may_flags, struct file *file,
1198 struct nfsd_file **pnf)
1199{
1200 return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, false);
1201}
1202
1203/*
1204 * Note that fields may be added, removed or reordered in the future. Programs
1205 * scraping this file for info should test the labels to ensure they're
1206 * getting the correct field.
1207 */
1208int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
1209{
1210 unsigned long releases = 0, evictions = 0;
1211 unsigned long hits = 0, acquisitions = 0;
1212 unsigned int i, count = 0, buckets = 0;
1213 unsigned long lru = 0, total_age = 0;
1214
1215 /* Serialize with server shutdown */
1216 mutex_lock(&nfsd_mutex);
1217 if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) {
1218 struct bucket_table *tbl;
1219 struct rhashtable *ht;
1220
1221 lru = list_lru_count(&nfsd_file_lru);
1222
1223 rcu_read_lock();
1224 ht = &nfsd_file_rhltable.ht;
1225 count = atomic_read(&ht->nelems);
1226 tbl = rht_dereference_rcu(ht->tbl, ht);
1227 buckets = tbl->size;
1228 rcu_read_unlock();
1229 }
1230 mutex_unlock(&nfsd_mutex);
1231
1232 for_each_possible_cpu(i) {
1233 hits += per_cpu(nfsd_file_cache_hits, i);
1234 acquisitions += per_cpu(nfsd_file_acquisitions, i);
1235 releases += per_cpu(nfsd_file_releases, i);
1236 total_age += per_cpu(nfsd_file_total_age, i);
1237 evictions += per_cpu(nfsd_file_evictions, i);
1238 }
1239
1240 seq_printf(m, "total inodes: %u\n", count);
1241 seq_printf(m, "hash buckets: %u\n", buckets);
1242 seq_printf(m, "lru entries: %lu\n", lru);
1243 seq_printf(m, "cache hits: %lu\n", hits);
1244 seq_printf(m, "acquisitions: %lu\n", acquisitions);
1245 seq_printf(m, "releases: %lu\n", releases);
1246 seq_printf(m, "evictions: %lu\n", evictions);
1247 if (releases)
1248 seq_printf(m, "mean age (ms): %ld\n", total_age / releases);
1249 else
1250 seq_printf(m, "mean age (ms): -\n");
1251 return 0;
1252}