Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kerne...
[linux-2.6-microblaze.git] / fs / nfsd / filecache.c
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
37 struct nfsd_fcache_bucket {
38         struct hlist_head       nfb_head;
39         spinlock_t              nfb_lock;
40         unsigned int            nfb_count;
41         unsigned int            nfb_maxcount;
42 };
43
44 static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
45
46 struct nfsd_fcache_disposal {
47         struct list_head list;
48         struct work_struct work;
49         struct net *net;
50         spinlock_t lock;
51         struct list_head freeme;
52         struct rcu_head rcu;
53 };
54
55 static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
56
57 static struct kmem_cache                *nfsd_file_slab;
58 static struct kmem_cache                *nfsd_file_mark_slab;
59 static struct nfsd_fcache_bucket        *nfsd_file_hashtbl;
60 static struct list_lru                  nfsd_file_lru;
61 static long                             nfsd_file_lru_flags;
62 static struct fsnotify_group            *nfsd_file_fsnotify_group;
63 static atomic_long_t                    nfsd_filecache_count;
64 static struct delayed_work              nfsd_filecache_laundrette;
65 static DEFINE_SPINLOCK(laundrette_lock);
66 static LIST_HEAD(laundrettes);
67
68 static void nfsd_file_gc(void);
69
70 static void
71 nfsd_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
82 static void
83 nfsd_file_slab_free(struct rcu_head *rcu)
84 {
85         struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
86
87         put_cred(nf->nf_cred);
88         kmem_cache_free(nfsd_file_slab, nf);
89 }
90
91 static void
92 nfsd_file_mark_free(struct fsnotify_mark *mark)
93 {
94         struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
95                                                   nfm_mark);
96
97         kmem_cache_free(nfsd_file_mark_slab, nfm);
98 }
99
100 static struct nfsd_file_mark *
101 nfsd_file_mark_get(struct nfsd_file_mark *nfm)
102 {
103         if (!refcount_inc_not_zero(&nfm->nfm_ref))
104                 return NULL;
105         return nfm;
106 }
107
108 static void
109 nfsd_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
117 static struct nfsd_file_mark *
118 nfsd_file_mark_find_or_create(struct nfsd_file *nf)
119 {
120         int                     err;
121         struct fsnotify_mark    *mark;
122         struct nfsd_file_mark   *nfm = NULL, *new;
123         struct inode *inode = nf->nf_inode;
124
125         do {
126                 mutex_lock(&nfsd_file_fsnotify_group->mark_mutex);
127                 mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
128                                 nfsd_file_fsnotify_group);
129                 if (mark) {
130                         nfm = nfsd_file_mark_get(container_of(mark,
131                                                  struct nfsd_file_mark,
132                                                  nfm_mark));
133                         mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
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
172 static struct nfsd_file *
173 nfsd_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
203 static bool
204 nfsd_file_free(struct nfsd_file *nf)
205 {
206         bool flush = false;
207
208         trace_nfsd_file_put_final(nf);
209         if (nf->nf_mark)
210                 nfsd_file_mark_put(nf->nf_mark);
211         if (nf->nf_file) {
212                 get_file(nf->nf_file);
213                 filp_close(nf->nf_file, NULL);
214                 fput(nf->nf_file);
215                 flush = true;
216         }
217         call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
218         return flush;
219 }
220
221 static bool
222 nfsd_file_check_writeback(struct nfsd_file *nf)
223 {
224         struct file *file = nf->nf_file;
225         struct address_space *mapping;
226
227         if (!file || !(file->f_mode & FMODE_WRITE))
228                 return false;
229         mapping = file->f_mapping;
230         return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
231                 mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
232 }
233
234 static int
235 nfsd_file_check_write_error(struct nfsd_file *nf)
236 {
237         struct file *file = nf->nf_file;
238
239         if (!file || !(file->f_mode & FMODE_WRITE))
240                 return 0;
241         return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err));
242 }
243
244 static void
245 nfsd_file_do_unhash(struct nfsd_file *nf)
246 {
247         lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
248
249         trace_nfsd_file_unhash(nf);
250
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
258 static bool
259 nfsd_file_unhash(struct nfsd_file *nf)
260 {
261         if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
262                 nfsd_file_do_unhash(nf);
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  */
273 static bool
274 nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *dispose)
275 {
276         lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
277
278         trace_nfsd_file_unhash_and_release_locked(nf);
279         if (!nfsd_file_unhash(nf))
280                 return false;
281         /* keep final reference for nfsd_file_lru_dispose */
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
289 static void
290 nfsd_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
300 void
301 nfsd_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
320 struct nfsd_file *
321 nfsd_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
328 static void
329 nfsd_file_dispose_list(struct list_head *dispose)
330 {
331         struct nfsd_file *nf;
332
333         while(!list_empty(dispose)) {
334                 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
335                 list_del(&nf->nf_lru);
336                 nfsd_file_put_noref(nf);
337         }
338 }
339
340 static void
341 nfsd_file_dispose_list_sync(struct list_head *dispose)
342 {
343         bool flush = false;
344         struct nfsd_file *nf;
345
346         while(!list_empty(dispose)) {
347                 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
348                 list_del(&nf->nf_lru);
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
358 static void
359 nfsd_file_list_remove_disposal(struct list_head *dst,
360                 struct nfsd_fcache_disposal *l)
361 {
362         spin_lock(&l->lock);
363         list_splice_init(&l->freeme, dst);
364         spin_unlock(&l->lock);
365 }
366
367 static void
368 nfsd_file_list_add_disposal(struct list_head *files, struct net *net)
369 {
370         struct nfsd_fcache_disposal *l;
371
372         rcu_read_lock();
373         list_for_each_entry_rcu(l, &laundrettes, list) {
374                 if (l->net == net) {
375                         spin_lock(&l->lock);
376                         list_splice_tail_init(files, &l->freeme);
377                         spin_unlock(&l->lock);
378                         queue_work(nfsd_filecache_wq, &l->work);
379                         break;
380                 }
381         }
382         rcu_read_unlock();
383 }
384
385 static void
386 nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src,
387                 struct net *net)
388 {
389         struct nfsd_file *nf, *tmp;
390
391         list_for_each_entry_safe(nf, tmp, src, nf_lru) {
392                 if (nf->nf_net == net)
393                         list_move_tail(&nf->nf_lru, dst);
394         }
395 }
396
397 static void
398 nfsd_file_dispose_list_delayed(struct list_head *dispose)
399 {
400         LIST_HEAD(list);
401         struct nfsd_file *nf;
402
403         while(!list_empty(dispose)) {
404                 nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
405                 nfsd_file_list_add_pernet(&list, dispose, nf->nf_net);
406                 nfsd_file_list_add_disposal(&list, nf->nf_net);
407         }
408 }
409
410 /*
411  * Note this can deadlock with nfsd_file_cache_purge.
412  */
413 static enum lru_status
414 nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
415                  spinlock_t *lock, void *arg)
416         __releases(lock)
417         __acquires(lock)
418 {
419         struct list_head *head = arg;
420         struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru);
421
422         /*
423          * Do a lockless refcount check. The hashtable holds one reference, so
424          * we look to see if anything else has a reference, or if any have
425          * been put since the shrinker last ran. Those don't get unhashed and
426          * released.
427          *
428          * Note that in the put path, we set the flag and then decrement the
429          * counter. Here we check the counter and then test and clear the flag.
430          * That order is deliberate to ensure that we can do this locklessly.
431          */
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;
450 out_skip:
451         return LRU_SKIP;
452 }
453
454 static unsigned long
455 nfsd_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
477 static void
478 nfsd_file_gc(void)
479 {
480         nfsd_file_lru_walk_list(NULL);
481 }
482
483 static void
484 nfsd_file_gc_worker(struct work_struct *work)
485 {
486         nfsd_file_gc();
487         nfsd_file_schedule_laundrette();
488 }
489
490 static unsigned long
491 nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc)
492 {
493         return list_lru_count(&nfsd_file_lru);
494 }
495
496 static unsigned long
497 nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc)
498 {
499         return nfsd_file_lru_walk_list(sc);
500 }
501
502 static struct shrinker  nfsd_file_shrinker = {
503         .scan_objects = nfsd_file_lru_scan,
504         .count_objects = nfsd_file_lru_count,
505         .seeks = 1,
506 };
507
508 static void
509 __nfsd_file_close_inode(struct inode *inode, unsigned int hashval,
510                         struct list_head *dispose)
511 {
512         struct nfsd_file        *nf;
513         struct hlist_node       *tmp;
514
515         spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
516         hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) {
517                 if (inode == nf->nf_inode)
518                         nfsd_file_unhash_and_release_locked(nf, dispose);
519         }
520         spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
521 }
522
523 /**
524  * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
525  * @inode: inode of the file to attempt to remove
526  *
527  * Walk the whole hash bucket, looking for any files that correspond to "inode".
528  * If any do, then unhash them and put the hashtable reference to them and
529  * destroy any that had their last reference put. Also ensure that any of the
530  * fputs also have their final __fput done as well.
531  */
532 void
533 nfsd_file_close_inode_sync(struct inode *inode)
534 {
535         unsigned int            hashval = (unsigned int)hash_long(inode->i_ino,
536                                                 NFSD_FILE_HASH_BITS);
537         LIST_HEAD(dispose);
538
539         __nfsd_file_close_inode(inode, hashval, &dispose);
540         trace_nfsd_file_close_inode_sync(inode, hashval, !list_empty(&dispose));
541         nfsd_file_dispose_list_sync(&dispose);
542 }
543
544 /**
545  * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
546  * @inode: inode of the file to attempt to remove
547  *
548  * Walk the whole hash bucket, looking for any files that correspond to "inode".
549  * If any do, then unhash them and put the hashtable reference to them and
550  * destroy any that had their last reference put.
551  */
552 static void
553 nfsd_file_close_inode(struct inode *inode)
554 {
555         unsigned int            hashval = (unsigned int)hash_long(inode->i_ino,
556                                                 NFSD_FILE_HASH_BITS);
557         LIST_HEAD(dispose);
558
559         __nfsd_file_close_inode(inode, hashval, &dispose);
560         trace_nfsd_file_close_inode(inode, hashval, !list_empty(&dispose));
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  */
573 static void
574 nfsd_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
584 static int
585 nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg,
586                             void *data)
587 {
588         struct file_lock *fl = data;
589
590         /* Only close files for F_SETLEASE leases */
591         if (fl->fl_flags & FL_LEASE)
592                 nfsd_file_close_inode_sync(file_inode(fl->fl_file));
593         return 0;
594 }
595
596 static struct notifier_block nfsd_file_lease_notifier = {
597         .notifier_call = nfsd_file_lease_notifier_call,
598 };
599
600 static int
601 nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask,
602                                 struct inode *inode, struct inode *dir,
603                                 const struct qstr *name)
604 {
605         trace_nfsd_file_fsnotify_handle_event(inode, mask);
606
607         /* Should be no marks on non-regular files */
608         if (!S_ISREG(inode->i_mode)) {
609                 WARN_ON_ONCE(1);
610                 return 0;
611         }
612
613         /* don't close files if this was not the last link */
614         if (mask & FS_ATTRIB) {
615                 if (inode->i_nlink)
616                         return 0;
617         }
618
619         nfsd_file_close_inode(inode);
620         return 0;
621 }
622
623
624 static const struct fsnotify_ops nfsd_file_fsnotify_ops = {
625         .handle_inode_event = nfsd_file_fsnotify_handle_event,
626         .free_mark = nfsd_file_mark_free,
627 };
628
629 int
630 nfsd_file_cache_init(void)
631 {
632         int             ret = -ENOMEM;
633         unsigned int    i;
634
635         clear_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags);
636
637         if (nfsd_file_hashtbl)
638                 return 0;
639
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);
699 out:
700         return ret;
701 out_notifier:
702         lease_unregister_notifier(&nfsd_file_lease_notifier);
703 out_shrinker:
704         unregister_shrinker(&nfsd_file_shrinker);
705 out_lru:
706         list_lru_destroy(&nfsd_file_lru);
707 out_err:
708         kmem_cache_destroy(nfsd_file_slab);
709         nfsd_file_slab = NULL;
710         kmem_cache_destroy(nfsd_file_mark_slab);
711         nfsd_file_mark_slab = NULL;
712         kfree(nfsd_file_hashtbl);
713         nfsd_file_hashtbl = NULL;
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  */
722 void
723 nfsd_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
754 static struct nfsd_fcache_disposal *
755 nfsd_alloc_fcache_disposal(struct net *net)
756 {
757         struct nfsd_fcache_disposal *l;
758
759         l = kmalloc(sizeof(*l), GFP_KERNEL);
760         if (!l)
761                 return NULL;
762         INIT_WORK(&l->work, nfsd_file_delayed_close);
763         l->net = net;
764         spin_lock_init(&l->lock);
765         INIT_LIST_HEAD(&l->freeme);
766         return l;
767 }
768
769 static void
770 nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
771 {
772         rcu_assign_pointer(l->net, NULL);
773         cancel_work_sync(&l->work);
774         nfsd_file_dispose_list(&l->freeme);
775         kfree_rcu(l, rcu);
776 }
777
778 static void
779 nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l)
780 {
781         spin_lock(&laundrette_lock);
782         list_add_tail_rcu(&l->list, &laundrettes);
783         spin_unlock(&laundrette_lock);
784 }
785
786 static void
787 nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l)
788 {
789         spin_lock(&laundrette_lock);
790         list_del_rcu(&l->list);
791         spin_unlock(&laundrette_lock);
792 }
793
794 static int
795 nfsd_alloc_fcache_disposal_net(struct net *net)
796 {
797         struct nfsd_fcache_disposal *l;
798
799         l = nfsd_alloc_fcache_disposal(net);
800         if (!l)
801                 return -ENOMEM;
802         nfsd_add_fcache_disposal(l);
803         return 0;
804 }
805
806 static void
807 nfsd_free_fcache_disposal_net(struct net *net)
808 {
809         struct nfsd_fcache_disposal *l;
810
811         rcu_read_lock();
812         list_for_each_entry_rcu(l, &laundrettes, list) {
813                 if (l->net != net)
814                         continue;
815                 nfsd_del_fcache_disposal(l);
816                 rcu_read_unlock();
817                 nfsd_free_fcache_disposal(l);
818                 return;
819         }
820         rcu_read_unlock();
821 }
822
823 int
824 nfsd_file_cache_start_net(struct net *net)
825 {
826         return nfsd_alloc_fcache_disposal_net(net);
827 }
828
829 void
830 nfsd_file_cache_shutdown_net(struct net *net)
831 {
832         nfsd_file_cache_purge(net);
833         nfsd_free_fcache_disposal_net(net);
834 }
835
836 void
837 nfsd_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
864 static bool
865 nfsd_match_cred(const struct cred *c1, const struct cred *c2)
866 {
867         int i;
868
869         if (!uid_eq(c1->fsuid, c2->fsuid))
870                 return false;
871         if (!gid_eq(c1->fsgid, c2->fsgid))
872                 return false;
873         if (c1->group_info == NULL || c2->group_info == NULL)
874                 return c1->group_info == c2->group_info;
875         if (c1->group_info->ngroups != c2->group_info->ngroups)
876                 return false;
877         for (i = 0; i < c1->group_info->ngroups; i++) {
878                 if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
879                         return false;
880         }
881         return true;
882 }
883
884 static struct nfsd_file *
885 nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
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 (nfsd_file_get(nf) != NULL)
902                         return nf;
903         }
904         return NULL;
905 }
906
907 /**
908  * nfsd_file_is_cached - are there any cached open files for this fh?
909  * @inode: inode of the file to check
910  *
911  * Scan the hashtable for open files that match this fh. Returns true if there
912  * are any, and false if not.
913  */
914 bool
915 nfsd_file_is_cached(struct inode *inode)
916 {
917         bool                    ret = false;
918         struct nfsd_file        *nf;
919         unsigned int            hashval;
920
921         hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
922
923         rcu_read_lock();
924         hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
925                                  nf_node) {
926                 if (inode == nf->nf_inode) {
927                         ret = true;
928                         break;
929                 }
930         }
931         rcu_read_unlock();
932         trace_nfsd_file_is_cached(inode, hashval, (int)ret);
933         return ret;
934 }
935
936 __be32
937 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
938                   unsigned int may_flags, struct nfsd_file **pnf)
939 {
940         __be32  status;
941         struct net *net = SVC_NET(rqstp);
942         struct nfsd_file *nf, *new;
943         struct inode *inode;
944         unsigned int hashval;
945         bool retry = true;
946
947         /* FIXME: skip this if fh_dentry is already set? */
948         status = fh_verify(rqstp, fhp, S_IFREG,
949                                 may_flags|NFSD_MAY_OWNER_OVERRIDE);
950         if (status != nfs_ok)
951                 return status;
952
953         inode = d_inode(fhp->fh_dentry);
954         hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
955 retry:
956         rcu_read_lock();
957         nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
958         rcu_read_unlock();
959         if (nf)
960                 goto wait_for_construction;
961
962         new = nfsd_file_alloc(inode, may_flags, hashval, net);
963         if (!new) {
964                 trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags,
965                                         NULL, nfserr_jukebox);
966                 return nfserr_jukebox;
967         }
968
969         spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
970         nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
971         if (nf == NULL)
972                 goto open_file;
973         spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
974         nfsd_file_slab_free(&new->nf_rcu);
975
976 wait_for_construction:
977         wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE);
978
979         /* Did construction of this file fail? */
980         if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
981                 if (!retry) {
982                         status = nfserr_jukebox;
983                         goto out;
984                 }
985                 retry = false;
986                 nfsd_file_put_noref(nf);
987                 goto retry;
988         }
989
990         this_cpu_inc(nfsd_file_cache_hits);
991
992         if (!(may_flags & NFSD_MAY_NOT_BREAK_LEASE)) {
993                 bool write = (may_flags & NFSD_MAY_WRITE);
994
995                 if (test_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags) ||
996                     (test_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags) && write)) {
997                         status = nfserrno(nfsd_open_break_lease(
998                                         file_inode(nf->nf_file), may_flags));
999                         if (status == nfs_ok) {
1000                                 clear_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags);
1001                                 if (write)
1002                                         clear_bit(NFSD_FILE_BREAK_WRITE,
1003                                                   &nf->nf_flags);
1004                         }
1005                 }
1006         }
1007 out:
1008         if (status == nfs_ok) {
1009                 *pnf = nf;
1010         } else {
1011                 nfsd_file_put(nf);
1012                 nf = NULL;
1013         }
1014
1015         trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, nf, status);
1016         return status;
1017 open_file:
1018         nf = new;
1019         /* Take reference for the hashtable */
1020         refcount_inc(&nf->nf_ref);
1021         __set_bit(NFSD_FILE_HASHED, &nf->nf_flags);
1022         __set_bit(NFSD_FILE_PENDING, &nf->nf_flags);
1023         list_lru_add(&nfsd_file_lru, &nf->nf_lru);
1024         hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head);
1025         ++nfsd_file_hashtbl[hashval].nfb_count;
1026         nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount,
1027                         nfsd_file_hashtbl[hashval].nfb_count);
1028         spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
1029         if (atomic_long_inc_return(&nfsd_filecache_count) >= NFSD_FILE_LRU_THRESHOLD)
1030                 nfsd_file_gc();
1031
1032         nf->nf_mark = nfsd_file_mark_find_or_create(nf);
1033         if (nf->nf_mark)
1034                 status = nfsd_open_verified(rqstp, fhp, S_IFREG,
1035                                 may_flags, &nf->nf_file);
1036         else
1037                 status = nfserr_jukebox;
1038         /*
1039          * If construction failed, or we raced with a call to unlink()
1040          * then unhash.
1041          */
1042         if (status != nfs_ok || inode->i_nlink == 0) {
1043                 bool do_free;
1044                 spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
1045                 do_free = nfsd_file_unhash(nf);
1046                 spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
1047                 if (do_free)
1048                         nfsd_file_put_noref(nf);
1049         }
1050         clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags);
1051         smp_mb__after_atomic();
1052         wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING);
1053         goto out;
1054 }
1055
1056 /*
1057  * Note that fields may be added, removed or reordered in the future. Programs
1058  * scraping this file for info should test the labels to ensure they're
1059  * getting the correct field.
1060  */
1061 static int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
1062 {
1063         unsigned int i, count = 0, longest = 0;
1064         unsigned long hits = 0;
1065
1066         /*
1067          * No need for spinlocks here since we're not terribly interested in
1068          * accuracy. We do take the nfsd_mutex simply to ensure that we
1069          * don't end up racing with server shutdown
1070          */
1071         mutex_lock(&nfsd_mutex);
1072         if (nfsd_file_hashtbl) {
1073                 for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
1074                         count += nfsd_file_hashtbl[i].nfb_count;
1075                         longest = max(longest, nfsd_file_hashtbl[i].nfb_count);
1076                 }
1077         }
1078         mutex_unlock(&nfsd_mutex);
1079
1080         for_each_possible_cpu(i)
1081                 hits += per_cpu(nfsd_file_cache_hits, i);
1082
1083         seq_printf(m, "total entries: %u\n", count);
1084         seq_printf(m, "longest chain: %u\n", longest);
1085         seq_printf(m, "cache hits:    %lu\n", hits);
1086         return 0;
1087 }
1088
1089 int nfsd_file_cache_stats_open(struct inode *inode, struct file *file)
1090 {
1091         return single_open(file, nfsd_file_cache_stats_show, NULL);
1092 }