diff options
Diffstat (limited to 'fs/mbcache.c')
| -rw-r--r-- | fs/mbcache.c | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/fs/mbcache.c b/fs/mbcache.c index b19be429d655..d818fd236787 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -10,13 +10,14 @@ /* * Mbcache is a simple key-value store. Keys need not be unique, however * key-value pairs are expected to be unique (we use this fact in - * mb_cache_entry_delete_block()). + * mb_cache_entry_delete()). * * Ext2 and ext4 use this cache for deduplication of extended attribute blocks. - * They use hash of a block contents as a key and block number as a value. - * That's why keys need not be unique (different xattr blocks may end up having - * the same hash). However block number always uniquely identifies a cache - * entry. + * Ext4 also uses it for deduplication of xattr values stored in inodes. + * They use hash of data as a key and provide a value that may represent a + * block or inode number. That's why keys need not be unique (hash of different + * data may be the same). However user provided value always uniquely + * identifies a cache entry. * * We provide functions for creation and removal of entries, search by key, * and a special "delete entry with given key-value pair" operation. Fixed @@ -62,15 +63,15 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache, * @cache - cache where the entry should be created * @mask - gfp mask with which the entry should be allocated * @key - key of the entry - * @block - block that contains data - * @reusable - is the block reusable by other inodes? + * @value - value of the entry + * @reusable - is the entry reusable by others? * - * Creates entry in @cache with key @key and records that data is stored in - * block @block. The function returns -EBUSY if entry with the same key - * and for the same block already exists in cache. Otherwise 0 is returned. + * Creates entry in @cache with key @key and value @value. The function returns + * -EBUSY if entry with the same key and value already exists in cache. + * Otherwise 0 is returned. */ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, - sector_t block, bool reusable) + u64 value, bool reusable) { struct mb_cache_entry *entry, *dup; struct hlist_bl_node *dup_node; @@ -91,12 +92,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, /* One ref for hash, one ref returned */ atomic_set(&entry->e_refcnt, 1); entry->e_key = key; - entry->e_block = block; + entry->e_value = value; entry->e_reusable = reusable; head = mb_cache_entry_head(cache, key); hlist_bl_lock(head); hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) { - if (dup->e_key == key && dup->e_block == block) { + if (dup->e_key == key && dup->e_value == value) { hlist_bl_unlock(head); kmem_cache_free(mb_entry_cache, entry); return -EBUSY; @@ -187,13 +188,13 @@ struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, EXPORT_SYMBOL(mb_cache_entry_find_next); /* - * mb_cache_entry_get - get a cache entry by block number (and key) + * mb_cache_entry_get - get a cache entry by value (and key) * @cache - cache we work with - * @key - key of block number @block - * @block - block number + * @key - key + * @value - value */ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, - sector_t block) + u64 value) { struct hlist_bl_node *node; struct hlist_bl_head *head; @@ -202,7 +203,7 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, head = mb_cache_entry_head(cache, key); hlist_bl_lock(head); hlist_bl_for_each_entry(entry, node, head, e_hash_list) { - if (entry->e_key == key && entry->e_block == block) { + if (entry->e_key == key && entry->e_value == value) { atomic_inc(&entry->e_refcnt); goto out; } @@ -214,15 +215,14 @@ out: } EXPORT_SYMBOL(mb_cache_entry_get); -/* mb_cache_entry_delete_block - remove information about block from cache +/* mb_cache_entry_delete - remove a cache entry * @cache - cache we work with - * @key - key of block @block - * @block - block number + * @key - key + * @value - value * - * Remove entry from cache @cache with key @key with data stored in @block. + * Remove entry from cache @cache with key @key and value @value. */ -void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, - sector_t block) +void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value) { struct hlist_bl_node *node; struct hlist_bl_head *head; @@ -231,7 +231,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, head = mb_cache_entry_head(cache, key); hlist_bl_lock(head); hlist_bl_for_each_entry(entry, node, head, e_hash_list) { - if (entry->e_key == key && entry->e_block == block) { + if (entry->e_key == key && entry->e_value == value) { /* We keep hash list reference to keep entry alive */ hlist_bl_del_init(&entry->e_hash_list); hlist_bl_unlock(head); @@ -248,7 +248,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, } hlist_bl_unlock(head); } -EXPORT_SYMBOL(mb_cache_entry_delete_block); +EXPORT_SYMBOL(mb_cache_entry_delete); /* mb_cache_entry_touch - cache entry got used * @cache - cache the entry belongs to |