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1/*
2 * Open file cache.
3 *
4 * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
5 */
6
7#include <linux/hash.h>
8#include <linux/slab.h>
9#include <linux/file.h>
10#include <linux/sched.h>
11#include <linux/list_lru.h>
12#include <linux/fsnotify_backend.h>
13#include <linux/fsnotify.h>
14#include <linux/seq_file.h>
15
16#include "vfs.h"
17#include "nfsd.h"
18#include "nfsfh.h"
19#include "netns.h"
20#include "filecache.h"
21#include "trace.h"
22
23#define NFSDDBG_FACILITY NFSDDBG_FH
24
25/* FIXME: dynamically size this for the machine somehow? */
26#define NFSD_FILE_HASH_BITS 12
27#define NFSD_FILE_HASH_SIZE (1 << NFSD_FILE_HASH_BITS)
28#define NFSD_LAUNDRETTE_DELAY (2 * HZ)
29
30#define NFSD_FILE_SHUTDOWN (1)
31#define NFSD_FILE_LRU_THRESHOLD (4096UL)
32#define NFSD_FILE_LRU_LIMIT (NFSD_FILE_LRU_THRESHOLD << 2)
33
34/* We only care about NFSD_MAY_READ/WRITE for this cache */
35#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE)
36
37struct nfsd_fcache_bucket {
38 struct hlist_head nfb_head;
39 spinlock_t nfb_lock;
40 unsigned int nfb_count;
41 unsigned int nfb_maxcount;
42};
43
44static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
45
46struct nfsd_fcache_disposal {
47 struct list_head list;
48 struct work_struct work;
49 struct net *net;
50 spinlock_t lock;
51 struct list_head freeme;
52 struct rcu_head rcu;
53};
54
55static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
56
57static struct kmem_cache *nfsd_file_slab;
58static struct kmem_cache *nfsd_file_mark_slab;
59static struct nfsd_fcache_bucket *nfsd_file_hashtbl;
60static struct list_lru nfsd_file_lru;
61static long nfsd_file_lru_flags;
62static struct fsnotify_group *nfsd_file_fsnotify_group;
63static atomic_long_t nfsd_filecache_count;
64static struct delayed_work nfsd_filecache_laundrette;
65static DEFINE_SPINLOCK(laundrette_lock);
66static LIST_HEAD(laundrettes);
67
68static void nfsd_file_gc(void);
69
70static void
71nfsd_file_schedule_laundrette(void)
72{
73 long count = atomic_long_read(&nfsd_filecache_count);
74
75 if (count == 0 || test_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags))
76 return;
77
78 queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
79 NFSD_LAUNDRETTE_DELAY);
80}
81
82static void
83nfsd_file_slab_free(struct rcu_head *rcu)
84{
85 struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
86
87 put_cred(nf->nf_cred);
88 kmem_cache_free(nfsd_file_slab, nf);
89}
90
91static void
92nfsd_file_mark_free(struct fsnotify_mark *mark)
93{
94 struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
95 nfm_mark);
96
97 kmem_cache_free(nfsd_file_mark_slab, nfm);
98}
99
100static struct nfsd_file_mark *
101nfsd_file_mark_get(struct nfsd_file_mark *nfm)
102{
103 if (!refcount_inc_not_zero(&nfm->nfm_ref))
104 return NULL;
105 return nfm;
106}
107
108static void
109nfsd_file_mark_put(struct nfsd_file_mark *nfm)
110{
111 if (refcount_dec_and_test(&nfm->nfm_ref)) {
112 fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
113 fsnotify_put_mark(&nfm->nfm_mark);
114 }
115}
116
117static struct nfsd_file_mark *
118nfsd_file_mark_find_or_create(struct nfsd_file *nf)
119{
120 int err;
121 struct fsnotify_mark *mark;
122 struct nfsd_file_mark *nfm = NULL, *new;
123 struct inode *inode = nf->nf_inode;
124
125 do {
126 mutex_lock(&nfsd_file_fsnotify_group->mark_mutex);
127 mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
128 nfsd_file_fsnotify_group);
129 if (mark) {
130 nfm = nfsd_file_mark_get(container_of(mark,
131 struct nfsd_file_mark,
132 nfm_mark));
133 mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
134 if (nfm) {
135 fsnotify_put_mark(mark);
136 break;
137 }
138 /* Avoid soft lockup race with nfsd_file_mark_put() */
139 fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
140 fsnotify_put_mark(mark);
141 } else
142 mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
143
144 /* allocate a new nfm */
145 new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
146 if (!new)
147 return NULL;
148 fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);
149 new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;
150 refcount_set(&new->nfm_ref, 1);
151
152 err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0);
153
154 /*
155 * If the add was successful, then return the object.
156 * Otherwise, we need to put the reference we hold on the
157 * nfm_mark. The fsnotify code will take a reference and put
158 * it on failure, so we can't just free it directly. It's also
159 * not safe to call fsnotify_destroy_mark on it as the
160 * mark->group will be NULL. Thus, we can't let the nfm_ref
161 * counter drive the destruction at this point.
162 */
163 if (likely(!err))
164 nfm = new;
165 else
166 fsnotify_put_mark(&new->nfm_mark);
167 } while (unlikely(err == -EEXIST));
168
169 return nfm;
170}
171
172static struct nfsd_file *
173nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval,
174 struct net *net)
175{
176 struct nfsd_file *nf;
177
178 nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
179 if (nf) {
180 INIT_HLIST_NODE(&nf->nf_node);
181 INIT_LIST_HEAD(&nf->nf_lru);
182 nf->nf_file = NULL;
183 nf->nf_cred = get_current_cred();
184 nf->nf_net = net;
185 nf->nf_flags = 0;
186 nf->nf_inode = inode;
187 nf->nf_hashval = hashval;
188 refcount_set(&nf->nf_ref, 1);
189 nf->nf_may = may & NFSD_FILE_MAY_MASK;
190 if (may & NFSD_MAY_NOT_BREAK_LEASE) {
191 if (may & NFSD_MAY_WRITE)
192 __set_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags);
193 if (may & NFSD_MAY_READ)
194 __set_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags);
195 }
196 nf->nf_mark = NULL;
197 init_rwsem(&nf->nf_rwsem);
198 trace_nfsd_file_alloc(nf);
199 }
200 return nf;
201}
202
203static bool
204nfsd_file_free(struct nfsd_file *nf)
205{
206 bool flush = false;
207
208 trace_nfsd_file_put_final(nf);
209 if (nf->nf_mark)
210 nfsd_file_mark_put(nf->nf_mark);
211 if (nf->nf_file) {
212 get_file(nf->nf_file);
213 filp_close(nf->nf_file, NULL);
214 fput(nf->nf_file);
215 flush = true;
216 }
217 call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
218 return flush;
219}
220
221static bool
222nfsd_file_check_writeback(struct nfsd_file *nf)
223{
224 struct file *file = nf->nf_file;
225 struct address_space *mapping;
226
227 if (!file || !(file->f_mode & FMODE_WRITE))
228 return false;
229 mapping = file->f_mapping;
230 return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
231 mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
232}
233
234static int
235nfsd_file_check_write_error(struct nfsd_file *nf)
236{
237 struct file *file = nf->nf_file;
238
239 if (!file || !(file->f_mode & FMODE_WRITE))
240 return 0;
241 return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err));
242}
243
244static void
245nfsd_file_do_unhash(struct nfsd_file *nf)
246{
247 lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
248
249 trace_nfsd_file_unhash(nf);
250
251 if (nfsd_file_check_write_error(nf))
252 nfsd_reset_boot_verifier(net_generic(nf->nf_net, nfsd_net_id));
253 --nfsd_file_hashtbl[nf->nf_hashval].nfb_count;
254 hlist_del_rcu(&nf->nf_node);
255 atomic_long_dec(&nfsd_filecache_count);
256}
257
258static bool
259nfsd_file_unhash(struct nfsd_file *nf)
260{
261 if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
262 nfsd_file_do_unhash(nf);
263 if (!list_empty(&nf->nf_lru))
264 list_lru_del(&nfsd_file_lru, &nf->nf_lru);
265 return true;
266 }
267 return false;
268}
269
270/*
271 * Return true if the file was unhashed.
272 */
273static bool
274nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *dispose)
275{
276 lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
277
278 trace_nfsd_file_unhash_and_release_locked(nf);
279 if (!nfsd_file_unhash(nf))
280 return false;
281 /* keep final reference for nfsd_file_lru_dispose */
282 if (refcount_dec_not_one(&nf->nf_ref))
283 return true;
284
285 list_add(&nf->nf_lru, dispose);
286 return true;
287}
288
289static void
290nfsd_file_put_noref(struct nfsd_file *nf)
291{
292 trace_nfsd_file_put(nf);
293
294 if (refcount_dec_and_test(&nf->nf_ref)) {
295 WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags));
296 nfsd_file_free(nf);
297 }
298}
299
300void
301nfsd_file_put(struct nfsd_file *nf)
302{
303 bool is_hashed;
304
305 set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
306 if (refcount_read(&nf->nf_ref) > 2 || !nf->nf_file) {
307 nfsd_file_put_noref(nf);
308 return;
309 }
310
311 filemap_flush(nf->nf_file->f_mapping);
312 is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
313 nfsd_file_put_noref(nf);
314 if (is_hashed)
315 nfsd_file_schedule_laundrette();
316 if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT)
317 nfsd_file_gc();
318}
319
320struct nfsd_file *
321nfsd_file_get(struct nfsd_file *nf)
322{
323 if (likely(refcount_inc_not_zero(&nf->nf_ref)))
324 return nf;
325 return NULL;
326}
327
328static void
329nfsd_file_dispose_list(struct list_head *dispose)
330{
331 struct nfsd_file *nf;
332
333 while(!list_empty(dispose)) {
334 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
335 list_del(&nf->nf_lru);
336 nfsd_file_put_noref(nf);
337 }
338}
339
340static void
341nfsd_file_dispose_list_sync(struct list_head *dispose)
342{
343 bool flush = false;
344 struct nfsd_file *nf;
345
346 while(!list_empty(dispose)) {
347 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
348 list_del(&nf->nf_lru);
349 if (!refcount_dec_and_test(&nf->nf_ref))
350 continue;
351 if (nfsd_file_free(nf))
352 flush = true;
353 }
354 if (flush)
355 flush_delayed_fput();
356}
357
358static void
359nfsd_file_list_remove_disposal(struct list_head *dst,
360 struct nfsd_fcache_disposal *l)
361{
362 spin_lock(&l->lock);
363 list_splice_init(&l->freeme, dst);
364 spin_unlock(&l->lock);
365}
366
367static void
368nfsd_file_list_add_disposal(struct list_head *files, struct net *net)
369{
370 struct nfsd_fcache_disposal *l;
371
372 rcu_read_lock();
373 list_for_each_entry_rcu(l, &laundrettes, list) {
374 if (l->net == net) {
375 spin_lock(&l->lock);
376 list_splice_tail_init(files, &l->freeme);
377 spin_unlock(&l->lock);
378 queue_work(nfsd_filecache_wq, &l->work);
379 break;
380 }
381 }
382 rcu_read_unlock();
383}
384
385static void
386nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src,
387 struct net *net)
388{
389 struct nfsd_file *nf, *tmp;
390
391 list_for_each_entry_safe(nf, tmp, src, nf_lru) {
392 if (nf->nf_net == net)
393 list_move_tail(&nf->nf_lru, dst);
394 }
395}
396
397static void
398nfsd_file_dispose_list_delayed(struct list_head *dispose)
399{
400 LIST_HEAD(list);
401 struct nfsd_file *nf;
402
403 while(!list_empty(dispose)) {
404 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
405 nfsd_file_list_add_pernet(&list, dispose, nf->nf_net);
406 nfsd_file_list_add_disposal(&list, nf->nf_net);
407 }
408}
409
410/*
411 * Note this can deadlock with nfsd_file_cache_purge.
412 */
413static enum lru_status
414nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
415 spinlock_t *lock, void *arg)
416 __releases(lock)
417 __acquires(lock)
418{
419 struct list_head *head = arg;
420 struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru);
421
422 /*
423 * Do a lockless refcount check. The hashtable holds one reference, so
424 * we look to see if anything else has a reference, or if any have
425 * been put since the shrinker last ran. Those don't get unhashed and
426 * released.
427 *
428 * Note that in the put path, we set the flag and then decrement the
429 * counter. Here we check the counter and then test and clear the flag.
430 * That order is deliberate to ensure that we can do this locklessly.
431 */
432 if (refcount_read(&nf->nf_ref) > 1)
433 goto out_skip;
434
435 /*
436 * Don't throw out files that are still undergoing I/O or
437 * that have uncleared errors pending.
438 */
439 if (nfsd_file_check_writeback(nf))
440 goto out_skip;
441
442 if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags))
443 goto out_skip;
444
445 if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags))
446 goto out_skip;
447
448 list_lru_isolate_move(lru, &nf->nf_lru, head);
449 return LRU_REMOVED;
450out_skip:
451 return LRU_SKIP;
452}
453
454static unsigned long
455nfsd_file_lru_walk_list(struct shrink_control *sc)
456{
457 LIST_HEAD(head);
458 struct nfsd_file *nf;
459 unsigned long ret;
460
461 if (sc)
462 ret = list_lru_shrink_walk(&nfsd_file_lru, sc,
463 nfsd_file_lru_cb, &head);
464 else
465 ret = list_lru_walk(&nfsd_file_lru,
466 nfsd_file_lru_cb,
467 &head, LONG_MAX);
468 list_for_each_entry(nf, &head, nf_lru) {
469 spin_lock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
470 nfsd_file_do_unhash(nf);
471 spin_unlock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
472 }
473 nfsd_file_dispose_list_delayed(&head);
474 return ret;
475}
476
477static void
478nfsd_file_gc(void)
479{
480 nfsd_file_lru_walk_list(NULL);
481}
482
483static void
484nfsd_file_gc_worker(struct work_struct *work)
485{
486 nfsd_file_gc();
487 nfsd_file_schedule_laundrette();
488}
489
490static unsigned long
491nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc)
492{
493 return list_lru_count(&nfsd_file_lru);
494}
495
496static unsigned long
497nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc)
498{
499 return nfsd_file_lru_walk_list(sc);
500}
501
502static struct shrinker nfsd_file_shrinker = {
503 .scan_objects = nfsd_file_lru_scan,
504 .count_objects = nfsd_file_lru_count,
505 .seeks = 1,
506};
507
508static void
509__nfsd_file_close_inode(struct inode *inode, unsigned int hashval,
510 struct list_head *dispose)
511{
512 struct nfsd_file *nf;
513 struct hlist_node *tmp;
514
515 spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
516 hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) {
517 if (inode == nf->nf_inode)
518 nfsd_file_unhash_and_release_locked(nf, dispose);
519 }
520 spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
521}
522
523/**
524 * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
525 * @inode: inode of the file to attempt to remove
526 *
527 * Walk the whole hash bucket, looking for any files that correspond to "inode".
528 * If any do, then unhash them and put the hashtable reference to them and
529 * destroy any that had their last reference put. Also ensure that any of the
530 * fputs also have their final __fput done as well.
531 */
532void
533nfsd_file_close_inode_sync(struct inode *inode)
534{
535 unsigned int hashval = (unsigned int)hash_long(inode->i_ino,
536 NFSD_FILE_HASH_BITS);
537 LIST_HEAD(dispose);
538
539 __nfsd_file_close_inode(inode, hashval, &dispose);
540 trace_nfsd_file_close_inode_sync(inode, hashval, !list_empty(&dispose));
541 nfsd_file_dispose_list_sync(&dispose);
542}
543
544/**
545 * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
546 * @inode: inode of the file to attempt to remove
547 *
548 * Walk the whole hash bucket, looking for any files that correspond to "inode".
549 * If any do, then unhash them and put the hashtable reference to them and
550 * destroy any that had their last reference put.
551 */
552static void
553nfsd_file_close_inode(struct inode *inode)
554{
555 unsigned int hashval = (unsigned int)hash_long(inode->i_ino,
556 NFSD_FILE_HASH_BITS);
557 LIST_HEAD(dispose);
558
559 __nfsd_file_close_inode(inode, hashval, &dispose);
560 trace_nfsd_file_close_inode(inode, hashval, !list_empty(&dispose));
561 nfsd_file_dispose_list_delayed(&dispose);
562}
563
564/**
565 * nfsd_file_delayed_close - close unused nfsd_files
566 * @work: dummy
567 *
568 * Walk the LRU list and close any entries that have not been used since
569 * the last scan.
570 *
571 * Note this can deadlock with nfsd_file_cache_purge.
572 */
573static void
574nfsd_file_delayed_close(struct work_struct *work)
575{
576 LIST_HEAD(head);
577 struct nfsd_fcache_disposal *l = container_of(work,
578 struct nfsd_fcache_disposal, work);
579
580 nfsd_file_list_remove_disposal(&head, l);
581 nfsd_file_dispose_list(&head);
582}
583
584static int
585nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg,
586 void *data)
587{
588 struct file_lock *fl = data;
589
590 /* Only close files for F_SETLEASE leases */
591 if (fl->fl_flags & FL_LEASE)
592 nfsd_file_close_inode_sync(file_inode(fl->fl_file));
593 return 0;
594}
595
596static struct notifier_block nfsd_file_lease_notifier = {
597 .notifier_call = nfsd_file_lease_notifier_call,
598};
599
600static int
601nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask,
602 struct inode *inode, struct inode *dir,
603 const struct qstr *name, u32 cookie)
604{
605 trace_nfsd_file_fsnotify_handle_event(inode, mask);
606
607 /* Should be no marks on non-regular files */
608 if (!S_ISREG(inode->i_mode)) {
609 WARN_ON_ONCE(1);
610 return 0;
611 }
612
613 /* don't close files if this was not the last link */
614 if (mask & FS_ATTRIB) {
615 if (inode->i_nlink)
616 return 0;
617 }
618
619 nfsd_file_close_inode(inode);
620 return 0;
621}
622
623
624static const struct fsnotify_ops nfsd_file_fsnotify_ops = {
625 .handle_inode_event = nfsd_file_fsnotify_handle_event,
626 .free_mark = nfsd_file_mark_free,
627};
628
629int
630nfsd_file_cache_init(void)
631{
632 int ret = -ENOMEM;
633 unsigned int i;
634
635 clear_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags);
636
637 if (nfsd_file_hashtbl)
638 return 0;
639
640 nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0);
641 if (!nfsd_filecache_wq)
642 goto out;
643
644 nfsd_file_hashtbl = kcalloc(NFSD_FILE_HASH_SIZE,
645 sizeof(*nfsd_file_hashtbl), GFP_KERNEL);
646 if (!nfsd_file_hashtbl) {
647 pr_err("nfsd: unable to allocate nfsd_file_hashtbl\n");
648 goto out_err;
649 }
650
651 nfsd_file_slab = kmem_cache_create("nfsd_file",
652 sizeof(struct nfsd_file), 0, 0, NULL);
653 if (!nfsd_file_slab) {
654 pr_err("nfsd: unable to create nfsd_file_slab\n");
655 goto out_err;
656 }
657
658 nfsd_file_mark_slab = kmem_cache_create("nfsd_file_mark",
659 sizeof(struct nfsd_file_mark), 0, 0, NULL);
660 if (!nfsd_file_mark_slab) {
661 pr_err("nfsd: unable to create nfsd_file_mark_slab\n");
662 goto out_err;
663 }
664
665
666 ret = list_lru_init(&nfsd_file_lru);
667 if (ret) {
668 pr_err("nfsd: failed to init nfsd_file_lru: %d\n", ret);
669 goto out_err;
670 }
671
672 ret = register_shrinker(&nfsd_file_shrinker);
673 if (ret) {
674 pr_err("nfsd: failed to register nfsd_file_shrinker: %d\n", ret);
675 goto out_lru;
676 }
677
678 ret = lease_register_notifier(&nfsd_file_lease_notifier);
679 if (ret) {
680 pr_err("nfsd: unable to register lease notifier: %d\n", ret);
681 goto out_shrinker;
682 }
683
684 nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops);
685 if (IS_ERR(nfsd_file_fsnotify_group)) {
686 pr_err("nfsd: unable to create fsnotify group: %ld\n",
687 PTR_ERR(nfsd_file_fsnotify_group));
688 ret = PTR_ERR(nfsd_file_fsnotify_group);
689 nfsd_file_fsnotify_group = NULL;
690 goto out_notifier;
691 }
692
693 for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
694 INIT_HLIST_HEAD(&nfsd_file_hashtbl[i].nfb_head);
695 spin_lock_init(&nfsd_file_hashtbl[i].nfb_lock);
696 }
697
698 INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker);
699out:
700 return ret;
701out_notifier:
702 lease_unregister_notifier(&nfsd_file_lease_notifier);
703out_shrinker:
704 unregister_shrinker(&nfsd_file_shrinker);
705out_lru:
706 list_lru_destroy(&nfsd_file_lru);
707out_err:
708 kmem_cache_destroy(nfsd_file_slab);
709 nfsd_file_slab = NULL;
710 kmem_cache_destroy(nfsd_file_mark_slab);
711 nfsd_file_mark_slab = NULL;
712 kfree(nfsd_file_hashtbl);
713 nfsd_file_hashtbl = NULL;
714 destroy_workqueue(nfsd_filecache_wq);
715 nfsd_filecache_wq = NULL;
716 goto out;
717}
718
719/*
720 * Note this can deadlock with nfsd_file_lru_cb.
721 */
722void
723nfsd_file_cache_purge(struct net *net)
724{
725 unsigned int i;
726 struct nfsd_file *nf;
727 struct hlist_node *next;
728 LIST_HEAD(dispose);
729 bool del;
730
731 if (!nfsd_file_hashtbl)
732 return;
733
734 for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
735 struct nfsd_fcache_bucket *nfb = &nfsd_file_hashtbl[i];
736
737 spin_lock(&nfb->nfb_lock);
738 hlist_for_each_entry_safe(nf, next, &nfb->nfb_head, nf_node) {
739 if (net && nf->nf_net != net)
740 continue;
741 del = nfsd_file_unhash_and_release_locked(nf, &dispose);
742
743 /*
744 * Deadlock detected! Something marked this entry as
745 * unhased, but hasn't removed it from the hash list.
746 */
747 WARN_ON_ONCE(!del);
748 }
749 spin_unlock(&nfb->nfb_lock);
750 nfsd_file_dispose_list(&dispose);
751 }
752}
753
754static struct nfsd_fcache_disposal *
755nfsd_alloc_fcache_disposal(struct net *net)
756{
757 struct nfsd_fcache_disposal *l;
758
759 l = kmalloc(sizeof(*l), GFP_KERNEL);
760 if (!l)
761 return NULL;
762 INIT_WORK(&l->work, nfsd_file_delayed_close);
763 l->net = net;
764 spin_lock_init(&l->lock);
765 INIT_LIST_HEAD(&l->freeme);
766 return l;
767}
768
769static void
770nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
771{
772 rcu_assign_pointer(l->net, NULL);
773 cancel_work_sync(&l->work);
774 nfsd_file_dispose_list(&l->freeme);
775 kfree_rcu(l, rcu);
776}
777
778static void
779nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l)
780{
781 spin_lock(&laundrette_lock);
782 list_add_tail_rcu(&l->list, &laundrettes);
783 spin_unlock(&laundrette_lock);
784}
785
786static void
787nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l)
788{
789 spin_lock(&laundrette_lock);
790 list_del_rcu(&l->list);
791 spin_unlock(&laundrette_lock);
792}
793
794static int
795nfsd_alloc_fcache_disposal_net(struct net *net)
796{
797 struct nfsd_fcache_disposal *l;
798
799 l = nfsd_alloc_fcache_disposal(net);
800 if (!l)
801 return -ENOMEM;
802 nfsd_add_fcache_disposal(l);
803 return 0;
804}
805
806static void
807nfsd_free_fcache_disposal_net(struct net *net)
808{
809 struct nfsd_fcache_disposal *l;
810
811 rcu_read_lock();
812 list_for_each_entry_rcu(l, &laundrettes, list) {
813 if (l->net != net)
814 continue;
815 nfsd_del_fcache_disposal(l);
816 rcu_read_unlock();
817 nfsd_free_fcache_disposal(l);
818 return;
819 }
820 rcu_read_unlock();
821}
822
823int
824nfsd_file_cache_start_net(struct net *net)
825{
826 return nfsd_alloc_fcache_disposal_net(net);
827}
828
829void
830nfsd_file_cache_shutdown_net(struct net *net)
831{
832 nfsd_file_cache_purge(net);
833 nfsd_free_fcache_disposal_net(net);
834}
835
836void
837nfsd_file_cache_shutdown(void)
838{
839 set_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags);
840
841 lease_unregister_notifier(&nfsd_file_lease_notifier);
842 unregister_shrinker(&nfsd_file_shrinker);
843 /*
844 * make sure all callers of nfsd_file_lru_cb are done before
845 * calling nfsd_file_cache_purge
846 */
847 cancel_delayed_work_sync(&nfsd_filecache_laundrette);
848 nfsd_file_cache_purge(NULL);
849 list_lru_destroy(&nfsd_file_lru);
850 rcu_barrier();
851 fsnotify_put_group(nfsd_file_fsnotify_group);
852 nfsd_file_fsnotify_group = NULL;
853 kmem_cache_destroy(nfsd_file_slab);
854 nfsd_file_slab = NULL;
855 fsnotify_wait_marks_destroyed();
856 kmem_cache_destroy(nfsd_file_mark_slab);
857 nfsd_file_mark_slab = NULL;
858 kfree(nfsd_file_hashtbl);
859 nfsd_file_hashtbl = NULL;
860 destroy_workqueue(nfsd_filecache_wq);
861 nfsd_filecache_wq = NULL;
862}
863
864static bool
865nfsd_match_cred(const struct cred *c1, const struct cred *c2)
866{
867 int i;
868
869 if (!uid_eq(c1->fsuid, c2->fsuid))
870 return false;
871 if (!gid_eq(c1->fsgid, c2->fsgid))
872 return false;
873 if (c1->group_info == NULL || c2->group_info == NULL)
874 return c1->group_info == c2->group_info;
875 if (c1->group_info->ngroups != c2->group_info->ngroups)
876 return false;
877 for (i = 0; i < c1->group_info->ngroups; i++) {
878 if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
879 return false;
880 }
881 return true;
882}
883
884static struct nfsd_file *
885nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
886 unsigned int hashval, struct net *net)
887{
888 struct nfsd_file *nf;
889 unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
890
891 hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
892 nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) {
893 if (nf->nf_may != need)
894 continue;
895 if (nf->nf_inode != inode)
896 continue;
897 if (nf->nf_net != net)
898 continue;
899 if (!nfsd_match_cred(nf->nf_cred, current_cred()))
900 continue;
901 if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
902 continue;
903 if (nfsd_file_get(nf) != NULL)
904 return nf;
905 }
906 return NULL;
907}
908
909/**
910 * nfsd_file_is_cached - are there any cached open files for this fh?
911 * @inode: inode of the file to check
912 *
913 * Scan the hashtable for open files that match this fh. Returns true if there
914 * are any, and false if not.
915 */
916bool
917nfsd_file_is_cached(struct inode *inode)
918{
919 bool ret = false;
920 struct nfsd_file *nf;
921 unsigned int hashval;
922
923 hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
924
925 rcu_read_lock();
926 hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
927 nf_node) {
928 if (inode == nf->nf_inode) {
929 ret = true;
930 break;
931 }
932 }
933 rcu_read_unlock();
934 trace_nfsd_file_is_cached(inode, hashval, (int)ret);
935 return ret;
936}
937
938__be32
939nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
940 unsigned int may_flags, struct nfsd_file **pnf)
941{
942 __be32 status;
943 struct net *net = SVC_NET(rqstp);
944 struct nfsd_file *nf, *new;
945 struct inode *inode;
946 unsigned int hashval;
947 bool retry = true;
948
949 /* FIXME: skip this if fh_dentry is already set? */
950 status = fh_verify(rqstp, fhp, S_IFREG,
951 may_flags|NFSD_MAY_OWNER_OVERRIDE);
952 if (status != nfs_ok)
953 return status;
954
955 inode = d_inode(fhp->fh_dentry);
956 hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
957retry:
958 rcu_read_lock();
959 nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
960 rcu_read_unlock();
961 if (nf)
962 goto wait_for_construction;
963
964 new = nfsd_file_alloc(inode, may_flags, hashval, net);
965 if (!new) {
966 trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags,
967 NULL, nfserr_jukebox);
968 return nfserr_jukebox;
969 }
970
971 spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
972 nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
973 if (nf == NULL)
974 goto open_file;
975 spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
976 nfsd_file_slab_free(&new->nf_rcu);
977
978wait_for_construction:
979 wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE);
980
981 /* Did construction of this file fail? */
982 if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
983 if (!retry) {
984 status = nfserr_jukebox;
985 goto out;
986 }
987 retry = false;
988 nfsd_file_put_noref(nf);
989 goto retry;
990 }
991
992 this_cpu_inc(nfsd_file_cache_hits);
993
994 if (!(may_flags & NFSD_MAY_NOT_BREAK_LEASE)) {
995 bool write = (may_flags & NFSD_MAY_WRITE);
996
997 if (test_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags) ||
998 (test_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags) && write)) {
999 status = nfserrno(nfsd_open_break_lease(
1000 file_inode(nf->nf_file), may_flags));
1001 if (status == nfs_ok) {
1002 clear_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags);
1003 if (write)
1004 clear_bit(NFSD_FILE_BREAK_WRITE,
1005 &nf->nf_flags);
1006 }
1007 }
1008 }
1009out:
1010 if (status == nfs_ok) {
1011 *pnf = nf;
1012 } else {
1013 nfsd_file_put(nf);
1014 nf = NULL;
1015 }
1016
1017 trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, nf, status);
1018 return status;
1019open_file:
1020 nf = new;
1021 /* Take reference for the hashtable */
1022 refcount_inc(&nf->nf_ref);
1023 __set_bit(NFSD_FILE_HASHED, &nf->nf_flags);
1024 __set_bit(NFSD_FILE_PENDING, &nf->nf_flags);
1025 list_lru_add(&nfsd_file_lru, &nf->nf_lru);
1026 hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head);
1027 ++nfsd_file_hashtbl[hashval].nfb_count;
1028 nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount,
1029 nfsd_file_hashtbl[hashval].nfb_count);
1030 spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
1031 if (atomic_long_inc_return(&nfsd_filecache_count) >= NFSD_FILE_LRU_THRESHOLD)
1032 nfsd_file_gc();
1033
1034 nf->nf_mark = nfsd_file_mark_find_or_create(nf);
1035 if (nf->nf_mark)
1036 status = nfsd_open_verified(rqstp, fhp, S_IFREG,
1037 may_flags, &nf->nf_file);
1038 else
1039 status = nfserr_jukebox;
1040 /*
1041 * If construction failed, or we raced with a call to unlink()
1042 * then unhash.
1043 */
1044 if (status != nfs_ok || inode->i_nlink == 0) {
1045 bool do_free;
1046 spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
1047 do_free = nfsd_file_unhash(nf);
1048 spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
1049 if (do_free)
1050 nfsd_file_put_noref(nf);
1051 }
1052 clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags);
1053 smp_mb__after_atomic();
1054 wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING);
1055 goto out;
1056}
1057
1058/*
1059 * Note that fields may be added, removed or reordered in the future. Programs
1060 * scraping this file for info should test the labels to ensure they're
1061 * getting the correct field.
1062 */
1063static int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
1064{
1065 unsigned int i, count = 0, longest = 0;
1066 unsigned long hits = 0;
1067
1068 /*
1069 * No need for spinlocks here since we're not terribly interested in
1070 * accuracy. We do take the nfsd_mutex simply to ensure that we
1071 * don't end up racing with server shutdown
1072 */
1073 mutex_lock(&nfsd_mutex);
1074 if (nfsd_file_hashtbl) {
1075 for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
1076 count += nfsd_file_hashtbl[i].nfb_count;
1077 longest = max(longest, nfsd_file_hashtbl[i].nfb_count);
1078 }
1079 }
1080 mutex_unlock(&nfsd_mutex);
1081
1082 for_each_possible_cpu(i)
1083 hits += per_cpu(nfsd_file_cache_hits, i);
1084
1085 seq_printf(m, "total entries: %u\n", count);
1086 seq_printf(m, "longest chain: %u\n", longest);
1087 seq_printf(m, "cache hits: %lu\n", hits);
1088 return 0;
1089}
1090
1091int nfsd_file_cache_stats_open(struct inode *inode, struct file *file)
1092{
1093 return single_open(file, nfsd_file_cache_stats_show, NULL);
1094}