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mbcache: make mbcache naming more generic 

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
parent b6d9029df0
commit c07dfcb458
4 changed files with 40 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
fs/ext2/xattr.c
View File

@ -493,8 +493,8 @@ bad_block: ext2_error(sb, "ext2_xattr_set",
* This must happen under buffer lock for
* ext2_xattr_set2() to reliably detect modified block
*/
mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
hash, bh->b_blocknr);
mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
bh->b_blocknr);
/* keep the buffer locked while modifying it. */
} else {
@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
* This must happen under buffer lock for
* ext2_xattr_set2() to reliably detect freed block
*/
mb_cache_entry_delete_block(ext2_mb_cache,
hash, old_bh->b_blocknr);
mb_cache_entry_delete(ext2_mb_cache, hash,
old_bh->b_blocknr);
/* Free the old block. */
ea_bdebug(old_bh, "freeing");
ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
* This must happen under buffer lock for ext2_xattr_set2() to
* reliably detect freed block
*/
mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
hash, bh->b_blocknr);
mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
bh->b_blocknr);
ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
get_bh(bh);
bforget(bh);
@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
while (ce) {
struct buffer_head *bh;
bh = sb_bread(inode->i_sb, ce->e_block);
bh = sb_bread(inode->i_sb, ce->e_value);
if (!bh) {
ext2_error(inode->i_sb, "ext2_xattr_cache_find",
"inode %ld: block %ld read error",
inode->i_ino, (unsigned long) ce->e_block);
inode->i_ino, (unsigned long) ce->e_value);
} else {
lock_buffer(bh);
/*
@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
} else if (le32_to_cpu(HDR(bh)->h_refcount) >
EXT2_XATTR_REFCOUNT_MAX) {
ea_idebug(inode, "block %ld refcount %d>%d",
(unsigned long) ce->e_block,
(unsigned long) ce->e_value,
le32_to_cpu(HDR(bh)->h_refcount),
EXT2_XATTR_REFCOUNT_MAX);
} else if (!ext2_xattr_cmp(header, HDR(bh))) {

10
fs/ext4/xattr.c
View File

@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
* This must happen under buffer lock for
* ext4_xattr_block_set() to reliably detect freed block
*/
mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
get_bh(bh);
unlock_buffer(bh);
ext4_free_blocks(handle, inode, bh, 0, 1,
@ -1113,8 +1113,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
* ext4_xattr_block_set() to reliably detect modified
* block
*/
mb_cache_entry_delete_block(ext4_mb_cache, hash,
bs->bh->b_blocknr);
mb_cache_entry_delete(ext4_mb_cache, hash,
bs->bh->b_blocknr);
ea_bdebug(bs->bh, "modifying in-place");
error = ext4_xattr_set_entry(i, s, handle, inode);
if (!error) {
@ -2236,10 +2236,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
while (ce) {
struct buffer_head *bh;
bh = sb_bread(inode->i_sb, ce->e_block);
bh = sb_bread(inode->i_sb, ce->e_value);
if (!bh) {
EXT4_ERROR_INODE(inode, "block %lu read error",
(unsigned long) ce->e_block);
(unsigned long)ce->e_value);
} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
*pce = ce;
return bh;

43
fs/mbcache.c
View File

@ -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 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
}
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

11
include/linux/mbcache.h
View File

@ -19,15 +19,15 @@ struct mb_cache_entry {
u32 e_key;
u32 e_referenced:1;
u32 e_reusable:1;
/* Block number of hashed block - stable during lifetime of the entry */
sector_t e_block;
/* User provided value - stable during lifetime of the entry */
u64 e_value;
};
struct mb_cache *mb_cache_create(int bucket_bits);
void mb_cache_destroy(struct mb_cache *cache);
int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
sector_t block, bool reusable);
u64 value, bool reusable);
void __mb_cache_entry_free(struct mb_cache_entry *entry);
static inline int mb_cache_entry_put(struct mb_cache *cache,
struct mb_cache_entry *entry)
@ -38,10 +38,9 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
return 1;
}
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 mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
sector_t block);
u64 value);
struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
u32 key);
struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,