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,  in nfs4_xattr_alloc_cache()
294 	if (cache == NULL)  in nfs4_xattr_alloc_cache()
297 	kref_init(&cache->ref);  in nfs4_xattr_alloc_cache()
298 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_alloc_cache()
300 	return cache;  in nfs4_xattr_alloc_cache()
304  * Set the listxattr cache, which is a special-cased cache entry.
306  * the cache is being drained - this prevents a new listxattr
307  * cache from being added to what is now a stale cache.
310 nfs4_xattr_set_listcache(struct nfs4_xattr_cache *cache,  in nfs4_xattr_set_listcache()  argument
316 	spin_lock(&cache->listxattr_lock);  in nfs4_xattr_set_listcache()
318 	old = cache->listxattr;  in nfs4_xattr_set_listcache()
325 	cache->listxattr = new;  in nfs4_xattr_set_listcache()
334 	spin_unlock(&cache->listxattr_lock);  in nfs4_xattr_set_listcache()
340  * Unlink a cache from its parent inode, clearing out an invalid
341  * cache. Must be called with i_lock held.
364  * Discard a cache. Called by get_cache() if there was an old,
365  * invalid cache. Can also be called from a shrinker callback.
367  * The cache is dead, it has already been unlinked from its inode,
368  * and no longer appears on the cache LRU list.
376  * any way to 'find' this cache. Then, remove the entries from the hash
379  * At that point, the cache will remain empty and can be freed when the final
385 nfs4_xattr_discard_cache(struct nfs4_xattr_cache *cache)  in nfs4_xattr_discard_cache()  argument
392 	nfs4_xattr_set_listcache(cache, ERR_PTR(-ESTALE));  in nfs4_xattr_discard_cache()
395 		bucket = &cache->buckets[i];  in nfs4_xattr_discard_cache()
407 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_discard_cache()
409 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_discard_cache()
413  * Get a referenced copy of the cache structure. Avoid doing allocs
417  * This function only checks the NFS_INO_INVALID_XATTR cache validity bit
418  * and acts accordingly, replacing the cache when needed. For the read case
419  * (!add), this means that the caller must make sure that the cache
421  * revalidate_inode to do this. The attribute cache timeout (for the
430 	struct nfs4_xattr_cache *cache, *oldcache, *newcache;  in nfs4_xattr_get_cache()  local
434 	cache = oldcache = NULL;  in nfs4_xattr_get_cache()
441 		cache = nfsi->xattr_cache;  in nfs4_xattr_get_cache()
443 	if (cache != NULL)  in nfs4_xattr_get_cache()
444 		kref_get(&cache->ref);  in nfs4_xattr_get_cache()
448 	if (add && cache == NULL) {  in nfs4_xattr_get_cache()
451 		cache = nfs4_xattr_alloc_cache();  in nfs4_xattr_get_cache()
452 		if (cache == NULL)  in nfs4_xattr_get_cache()
458 			 * The cache was invalidated again. Give up,  in nfs4_xattr_get_cache()
463 			kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_get_cache()
464 			cache = NULL;  in nfs4_xattr_get_cache()
475 			kref_get(&cache->ref);  in nfs4_xattr_get_cache()
476 			nfsi->xattr_cache = cache;  in nfs4_xattr_get_cache()
477 			cache->inode = inode;  in nfs4_xattr_get_cache()
478 			list_lru_add(&nfs4_xattr_cache_lru, &cache->lru);  in nfs4_xattr_get_cache()
484 		 * If there was a race, throw away the cache we just  in nfs4_xattr_get_cache()
489 			kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_get_cache()
490 			cache = newcache;  in nfs4_xattr_get_cache()
496 	 * Discard the now orphaned old cache.  in nfs4_xattr_get_cache()
501 	return cache;  in nfs4_xattr_get_cache()
505 nfs4_xattr_hash_bucket(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_bucket()  argument
507 	return &cache->buckets[jhash(name, strlen(name), 0) &  in nfs4_xattr_hash_bucket()
508 	    (ARRAY_SIZE(cache->buckets) - 1)];  in nfs4_xattr_hash_bucket()
527 nfs4_xattr_hash_add(struct nfs4_xattr_cache *cache,  in nfs4_xattr_hash_add()  argument
534 	bucket = nfs4_xattr_hash_bucket(cache, entry->xattr_name);  in nfs4_xattr_hash_add()
549 		atomic_long_inc(&cache->nent);  in nfs4_xattr_hash_add()
565 nfs4_xattr_hash_remove(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_remove()  argument
570 	bucket = nfs4_xattr_hash_bucket(cache, name);  in nfs4_xattr_hash_remove()
578 		atomic_long_dec(&cache->nent);  in nfs4_xattr_hash_remove()
588 nfs4_xattr_hash_find(struct nfs4_xattr_cache *cache, const char *name)  in nfs4_xattr_hash_find()  argument
593 	bucket = nfs4_xattr_hash_bucket(cache, name);  in nfs4_xattr_hash_find()
607  * Entry point to retrieve an entry from the cache.
612 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_get()  local
616 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_get()
617 	if (cache == NULL)  in nfs4_xattr_cache_get()
621 	entry = nfs4_xattr_hash_find(cache, name);  in nfs4_xattr_cache_get()
624 		dprintk("%s: cache hit '%s', len %lu\n", __func__,  in nfs4_xattr_cache_get()
637 		dprintk("%s: cache miss '%s'\n", __func__, name);  in nfs4_xattr_cache_get()
641 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_get()
647  * Retrieve a cached list of xattrs from the cache.
651 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_list()  local
655 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_list()
656 	if (cache == NULL)  in nfs4_xattr_cache_list()
659 	spin_lock(&cache->listxattr_lock);  in nfs4_xattr_cache_list()
661 	entry = cache->listxattr;  in nfs4_xattr_cache_list()
677 	spin_unlock(&cache->listxattr_lock);  in nfs4_xattr_cache_list()
679 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_list()
685  * Add an xattr to the cache.
687  * This also invalidates the xattr list cache.
692 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_add()  local
698 	cache = nfs4_xattr_get_cache(inode, 1);  in nfs4_xattr_cache_add()
699 	if (cache == NULL)  in nfs4_xattr_cache_add()
706 	(void)nfs4_xattr_set_listcache(cache, NULL);  in nfs4_xattr_cache_add()
708 	if (!nfs4_xattr_hash_add(cache, entry))  in nfs4_xattr_cache_add()
712 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_add()
717  * Remove an xattr from the cache.
719  * This also invalidates the xattr list cache.
723 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_remove()  local
727 	cache = nfs4_xattr_get_cache(inode, 0);  in nfs4_xattr_cache_remove()
728 	if (cache == NULL)  in nfs4_xattr_cache_remove()
731 	(void)nfs4_xattr_set_listcache(cache, NULL);  in nfs4_xattr_cache_remove()
732 	nfs4_xattr_hash_remove(cache, name);  in nfs4_xattr_cache_remove()
734 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_remove()
738  * Cache listxattr output, replacing any possible old one.
743 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_set_list()  local
746 	cache = nfs4_xattr_get_cache(inode, 1);  in nfs4_xattr_cache_set_list()
747 	if (cache == NULL)  in nfs4_xattr_cache_set_list()
755 	 * This is just there to be able to get to bucket->cache,  in nfs4_xattr_cache_set_list()
759 	entry->bucket = &cache->buckets[0];  in nfs4_xattr_cache_set_list()
761 	if (!nfs4_xattr_set_listcache(cache, entry))  in nfs4_xattr_cache_set_list()
765 	kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_set_list()
769  * Zap the entire cache. Called when an inode is evicted.
784  * The entry LRU is shrunk more aggressively than the cache LRU,
787  * Cache structures are freed only when they've become empty, after
829 	struct nfs4_xattr_cache *cache = container_of(item,  in cache_lru_isolate()  local
832 	if (atomic_long_read(&cache->nent) > 1)  in cache_lru_isolate()
836 	 * If a cache structure is on the LRU list, we know that  in cache_lru_isolate()
840 	inode = cache->inode;  in cache_lru_isolate()
845 	kref_get(&cache->ref);  in cache_lru_isolate()
847 	cache->inode = NULL;  in cache_lru_isolate()
850 	list_lru_isolate(lru, &cache->lru);  in cache_lru_isolate()
854 	list_add_tail(&cache->dispose, dispose);  in cache_lru_isolate()
863 	struct nfs4_xattr_cache *cache;  in nfs4_xattr_cache_scan()  local
868 		cache = list_first_entry(&dispose, struct nfs4_xattr_cache,  in nfs4_xattr_cache_scan()
870 		list_del_init(&cache->dispose);  in nfs4_xattr_cache_scan()
871 		nfs4_xattr_discard_cache(cache);  in nfs4_xattr_cache_scan()
872 		kref_put(&cache->ref, nfs4_xattr_free_cache_cb);  in nfs4_xattr_cache_scan()
894 	struct nfs4_xattr_cache *cache;  in entry_lru_isolate()  local
899 	cache = bucket->cache;  in entry_lru_isolate()
902 	 * Unhook the entry from its parent (either a cache bucket  in entry_lru_isolate()
903 	 * or a cache structure if it's a listxattr buf), so that  in entry_lru_isolate()
911 		/* Regular cache entry */  in entry_lru_isolate()
918 		atomic_long_dec(&cache->nent);  in entry_lru_isolate()
923 		/* Listxattr cache entry */  in entry_lru_isolate()
924 		if (!spin_trylock(&cache->listxattr_lock))  in entry_lru_isolate()
929 		cache->listxattr = NULL;  in entry_lru_isolate()
932 		spin_unlock(&cache->listxattr_lock);  in entry_lru_isolate()
985 	struct nfs4_xattr_cache *cache = (struct nfs4_xattr_cache *)p;  in nfs4_xattr_cache_init_once()  local
987 	spin_lock_init(&cache->listxattr_lock);  in nfs4_xattr_cache_init_once()
988 	atomic_long_set(&cache->nent, 0);  in nfs4_xattr_cache_init_once()
989 	nfs4_xattr_hash_init(cache);  in nfs4_xattr_cache_init_once()
990 	cache->listxattr = NULL;  in nfs4_xattr_cache_init_once()
991 	INIT_LIST_HEAD(&cache->lru);  in nfs4_xattr_cache_init_once()
992 	INIT_LIST_HEAD(&cache->dispose);  in nfs4_xattr_cache_init_once()