6  * User extended attribute client side cache functions.
21  * a cache structure attached to NFS inodes. This structure is allocated
22  * when needed, and freed when the cache is zapped.
24  * The cache structure contains as hash table of entries, and a pointer
25  * to a special-cased entry for the listxattr cache.
28  * counting. The cache entries use a similar refcounting scheme.
30  * This makes freeing a cache, both from the shrinker and from the
31  * zap cache path, easy. It also means that, in current use cases,
40  * Two shrinkers deal with the cache entries themselves: one for
45  * The other shrinker frees the cache structures themselves.
64 	struct nfs4_xattr_cache *cache;  member
106 nfs4_xattr_hash_init(struct nfs4_xattr_cache *cache)  in nfs4_xattr_hash_init()  argument
111 		INIT_HLIST_HEAD(&cache->buckets[i].hlist);  in nfs4_xattr_hash_init()
112 		spin_lock_init(&cache->buckets[i].lock);  in nfs4_xattr_hash_init()
113 		cache->buckets[i].cache = cache;  in nfs4_xattr_hash_init()
114 		cache->buckets[i].draining = false;  in nfs4_xattr_hash_init()
125  * Wrapper functions to add a cache entry to the right LRU.
150  * This function allocates cache entries. They are the normal
152  * cache. Those allocations use the same entry so that they can be
155  * xattr cache entries are allocated together with names. If the
163  * @name:  Name of the extended attribute. NULL for listxattr cache
165  * @value: Value of attribute, or listxattr cache. NULL if the
270 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_free_cache_cb()  local
273 	cache = container_of(kref, struct nfs4_xattr_cache, ref);  in nfs4_xattr_free_cache_cb()
276 		if (WARN_ON(!hlist_empty(&cache->buckets[i].hlist)))  in nfs4_xattr_free_cache_cb()
278 		cache->buckets[i].draining = false;  in nfs4_xattr_free_cache_cb()
281 	cache->listxattr = NULL;  in nfs4_xattr_free_cache_cb()
283 	kmem_cache_free(nfs4_xattr_cache_cachep, cache);  in nfs4_xattr_free_cache_cb()
290 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_alloc_cache()  local
292 	cache = kmem_cache_alloc(nfs4_xattr_cache_cachep, GFP_KERNEL);  in nfs4_xattr_alloc_cache()
293 	if (cache == NULL)  in nfs4_xattr_alloc_cache()
296 	kref_init(&cache->ref);  in nfs4_xattr_alloc_cache()
297 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_alloc_cache()
299 	return cache;  in nfs4_xattr_alloc_cache()
303  * Set the listxattr cache, which is a special-cased cache entry.
305  * the cache is being drained - this prevents a new listxattr
306  * cache from being added to what is now a stale cache.
309 nfs4_xattr_set_listcache(struct nfs4_xattr_cache *cache,  in nfs4_xattr_set_listcache()  argument
315 	spin_lock(&cache->listxattr_lock);  in nfs4_xattr_set_listcache()
317 	old = cache->listxattr;  in nfs4_xattr_set_listcache()
324 	cache->listxattr = new;  in nfs4_xattr_set_listcache()
333 	spin_unlock(&cache->listxattr_lock);  in nfs4_xattr_set_listcache()
339  * Unlink a cache from its parent inode, clearing out an invalid
340  * cache. Must be called with i_lock held.
363  * Discard a cache. Called by get_cache() if there was an old,
364  * invalid cache. Can also be called from a shrinker callback.
366  * The cache is dead, it has already been unlinked from its inode,
367  * and no longer appears on the cache LRU list.
375  * any way to 'find' this cache. Then, remove the entries from the hash
378  * At that point, the cache will remain empty and can be freed when the final
384 nfs4_xattr_discard_cache(struct nfs4_xattr_cache *cache)  in nfs4_xattr_discard_cache()  argument
391 	nfs4_xattr_set_listcache(cache, ERR_PTR(-ESTALE));  in nfs4_xattr_discard_cache()
394 		bucket = &cache->buckets[i];  in nfs4_xattr_discard_cache()
406 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_discard_cache()
408 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_discard_cache()
412  * Get a referenced copy of the cache structure. Avoid doing allocs
416  * This function only checks the NFS_INO_INVALID_XATTR cache validity bit
417  * and acts accordingly, replacing the cache when needed. For the read case
418  * (!add), this means that the caller must make sure that the cache
420  * revalidate_inode to do this. The attribute cache timeout (for the
429 	struct nfs4_xattr_cache *cache, *oldcache, *newcache;  in nfs4_xattr_get_cache()  local
433 	cache = oldcache = NULL;  in nfs4_xattr_get_cache()
440 		cache = nfsi->xattr_cache;  in nfs4_xattr_get_cache()
442 	if (cache != NULL)  in nfs4_xattr_get_cache()
443 		kref_get(&cache->ref);  in nfs4_xattr_get_cache()
447 	if (add && cache == NULL) {  in nfs4_xattr_get_cache()
450 		cache = nfs4_xattr_alloc_cache();  in nfs4_xattr_get_cache()
451 		if (cache == NULL)  in nfs4_xattr_get_cache()
457 			 * The cache was invalidated again. Give up,  in nfs4_xattr_get_cache()
462 			kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_get_cache()
463 			cache = NULL;  in nfs4_xattr_get_cache()
474 			kref_get(&cache->ref);  in nfs4_xattr_get_cache()
475 			nfsi->xattr_cache = cache;  in nfs4_xattr_get_cache()
476 			cache->inode = inode;  in nfs4_xattr_get_cache()
477 			list_lru_add(&nfs4_xattr_cache_lru, &cache->lru);  in nfs4_xattr_get_cache()
483 		 * If there was a race, throw away the cache we just  in nfs4_xattr_get_cache()
488 			kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_get_cache()
489 			cache = newcache;  in nfs4_xattr_get_cache()
495 	 * Discard the now orphaned old cache.  in nfs4_xattr_get_cache()
500 	return cache;  in nfs4_xattr_get_cache()
504 nfs4_xattr_hash_bucket(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_bucket()  argument
506 	return &cache->buckets[jhash(name, strlen(name), 0) &  in nfs4_xattr_hash_bucket()
507 	    (ARRAY_SIZE(cache->buckets) - 1)];  in nfs4_xattr_hash_bucket()
526 nfs4_xattr_hash_add(struct nfs4_xattr_cache *cache,  in nfs4_xattr_hash_add()  argument
533 	bucket = nfs4_xattr_hash_bucket(cache, entry->xattr_name);  in nfs4_xattr_hash_add()
548 		atomic_long_inc(&cache->nent);  in nfs4_xattr_hash_add()
564 nfs4_xattr_hash_remove(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_remove()  argument
569 	bucket = nfs4_xattr_hash_bucket(cache, name);  in nfs4_xattr_hash_remove()
577 		atomic_long_dec(&cache->nent);  in nfs4_xattr_hash_remove()
587 nfs4_xattr_hash_find(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_find()  argument
592 	bucket = nfs4_xattr_hash_bucket(cache, name);  in nfs4_xattr_hash_find()
606  * Entry point to retrieve an entry from the cache.
611 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_get()  local
615 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_get()
616 	if (cache == NULL)  in nfs4_xattr_cache_get()
620 	entry = nfs4_xattr_hash_find(cache, name);  in nfs4_xattr_cache_get()
623 		dprintk("%s: cache hit '%s', len %lu\n", __func__,  in nfs4_xattr_cache_get()
636 		dprintk("%s: cache miss '%s'\n", __func__, name);  in nfs4_xattr_cache_get()
640 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_get()
646  * Retrieve a cached list of xattrs from the cache.
650 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_list()  local
654 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_list()
655 	if (cache == NULL)  in nfs4_xattr_cache_list()
658 	spin_lock(&cache->listxattr_lock);  in nfs4_xattr_cache_list()
660 	entry = cache->listxattr;  in nfs4_xattr_cache_list()
676 	spin_unlock(&cache->listxattr_lock);  in nfs4_xattr_cache_list()
678 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_list()
684  * Add an xattr to the cache.
686  * This also invalidates the xattr list cache.
691 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_add()  local
697 	cache = nfs4_xattr_get_cache(inode, 1);  in nfs4_xattr_cache_add()
698 	if (cache == NULL)  in nfs4_xattr_cache_add()
705 	(void)nfs4_xattr_set_listcache(cache, NULL);  in nfs4_xattr_cache_add()
707 	if (!nfs4_xattr_hash_add(cache, entry))  in nfs4_xattr_cache_add()
711 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_add()
716  * Remove an xattr from the cache.
718  * This also invalidates the xattr list cache.
722 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_remove()  local
726 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_remove()
727 	if (cache == NULL)  in nfs4_xattr_cache_remove()
730 	(void)nfs4_xattr_set_listcache(cache, NULL);  in nfs4_xattr_cache_remove()
731 	nfs4_xattr_hash_remove(cache, name);  in nfs4_xattr_cache_remove()
733 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_remove()
737  * Cache listxattr output, replacing any possible old one.
742 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_set_list()  local
745 	cache = nfs4_xattr_get_cache(inode, 1);  in nfs4_xattr_cache_set_list()
746 	if (cache == NULL)  in nfs4_xattr_cache_set_list()
754 	 * This is just there to be able to get to bucket->cache,  in nfs4_xattr_cache_set_list()
758 	entry->bucket = &cache->buckets[0];  in nfs4_xattr_cache_set_list()
760 	if (!nfs4_xattr_set_listcache(cache, entry))  in nfs4_xattr_cache_set_list()
764 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_set_list()
768  * Zap the entire cache. Called when an inode is evicted.
783  * The entry LRU is shrunk more aggressively than the cache LRU,
786  * Cache structures are freed only when they've become empty, after
828 	struct nfs4_xattr_cache *cache = container_of(item,  in cache_lru_isolate()  local
831 	if (atomic_long_read(&cache->nent) > 1)  in cache_lru_isolate()
835 	 * If a cache structure is on the LRU list, we know that  in cache_lru_isolate()
839 	inode = cache->inode;  in cache_lru_isolate()
844 	kref_get(&cache->ref);  in cache_lru_isolate()
846 	cache->inode = NULL;  in cache_lru_isolate()
849 	list_lru_isolate(lru, &cache->lru);  in cache_lru_isolate()
853 	list_add_tail(&cache->dispose, dispose);  in cache_lru_isolate()
862 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_scan()  local
867 		cache = list_first_entry(&dispose, struct nfs4_xattr_cache,  in nfs4_xattr_cache_scan()
869 		list_del_init(&cache->dispose);  in nfs4_xattr_cache_scan()
870 		nfs4_xattr_discard_cache(cache);  in nfs4_xattr_cache_scan()
871 		kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_scan()
893 	struct nfs4_xattr_cache *cache;  in entry_lru_isolate()  local
898 	cache = bucket->cache;  in entry_lru_isolate()
901 	 * Unhook the entry from its parent (either a cache bucket  in entry_lru_isolate()
902 	 * or a cache structure if it's a listxattr buf), so that  in entry_lru_isolate()
910 		/* Regular cache entry */  in entry_lru_isolate()
917 		atomic_long_dec(&cache->nent);  in entry_lru_isolate()
922 		/* Listxattr cache entry */  in entry_lru_isolate()
923 		if (!spin_trylock(&cache->listxattr_lock))  in entry_lru_isolate()
928 		cache->listxattr = NULL;  in entry_lru_isolate()
931 		spin_unlock(&cache->listxattr_lock);  in entry_lru_isolate()
984 	struct nfs4_xattr_cache *cache = p;  in nfs4_xattr_cache_init_once()  local
986 	spin_lock_init(&cache->listxattr_lock);  in nfs4_xattr_cache_init_once()
987 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_cache_init_once()
988 	nfs4_xattr_hash_init(cache);  in nfs4_xattr_cache_init_once()
989 	cache->listxattr = NULL;  in nfs4_xattr_cache_init_once()
990 	INIT_LIST_HEAD(&cache->lru);  in nfs4_xattr_cache_init_once()
991 	INIT_LIST_HEAD(&cache->dispose);  in nfs4_xattr_cache_init_once()