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mbcache: make mbcache naming more generic

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Make names more generic so that mbcache usage is not limited to
block sharing. In a subsequent patch in the series
("ext4: xattr inode deduplication"), we start using the mbcache code
for sharing xattr inodes. With that patch, old mb_cache_entry.e_block
field could be holding either a block number or an inode number.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Tahsin Erdogan 2017-06-22 10:29:53 -04:00 • committed by Theodore Ts'o
commit c07dfcb458
1 changed files with 40 additions and 42 deletions
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43
fs/mbcache.c
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@ -10,7 +10,7 @@
/*
* 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.
@ -62,15 +62,15 @@ 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 +91,12 @@ 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 +187,13 @@ 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 +202,7 @@ 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 +214,14 @@ 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 +230,7 @@ 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 +247,7 @@ 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