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-rw-r--r--fs/ext2/xattr.c2
-rw-r--r--fs/ext4/xattr.c66
-rw-r--r--fs/mbcache.c38
3 files changed, 77 insertions, 29 deletions
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 71d58c2d7a19..1a5e3bff0b63 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -823,7 +823,7 @@ ext2_xattr_cache_insert(struct mb_cache *cache, struct buffer_head *bh)
__u32 hash = le32_to_cpu(HDR(bh)->h_hash);
int error;
- error = mb_cache_entry_create(cache, GFP_NOFS, hash, bh->b_blocknr);
+ error = mb_cache_entry_create(cache, GFP_NOFS, hash, bh->b_blocknr, 1);
if (error) {
if (error == -EBUSY) {
ea_bdebug(bh, "already in cache (%d cache entries)",
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index b661ae8332e3..0441e055c8e8 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -545,6 +545,8 @@ static void
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
+ struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
+ u32 hash, ref;
int error = 0;
BUFFER_TRACE(bh, "get_write_access");
@@ -553,23 +555,34 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
goto out;
lock_buffer(bh);
- if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
- __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
-
+ hash = le32_to_cpu(BHDR(bh)->h_hash);
+ ref = le32_to_cpu(BHDR(bh)->h_refcount);
+ if (ref == 1) {
ea_bdebug(bh, "refcount now=0; freeing");
/*
* This must happen under buffer lock for
* ext4_xattr_block_set() to reliably detect freed block
*/
- mb_cache_entry_delete_block(EXT4_GET_MB_CACHE(inode), hash,
- bh->b_blocknr);
+ mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
get_bh(bh);
unlock_buffer(bh);
ext4_free_blocks(handle, inode, bh, 0, 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
} else {
- le32_add_cpu(&BHDR(bh)->h_refcount, -1);
+ ref--;
+ BHDR(bh)->h_refcount = cpu_to_le32(ref);
+ if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
+ struct mb_cache_entry *ce;
+
+ ce = mb_cache_entry_get(ext4_mb_cache, hash,
+ bh->b_blocknr);
+ if (ce) {
+ ce->e_reusable = 1;
+ mb_cache_entry_put(ext4_mb_cache, ce);
+ }
+ }
+
/*
* Beware of this ugliness: Releasing of xattr block references
* from different inodes can race and so we have to protect
@@ -872,6 +885,8 @@ inserted:
if (new_bh == bs->bh)
ea_bdebug(new_bh, "keeping");
else {
+ u32 ref;
+
/* The old block is released after updating
the inode. */
error = dquot_alloc_block(inode,
@@ -886,15 +901,18 @@ inserted:
lock_buffer(new_bh);
/*
* We have to be careful about races with
- * freeing or rehashing of xattr block. Once we
- * hold buffer lock xattr block's state is
- * stable so we can check whether the block got
- * freed / rehashed or not. Since we unhash
- * mbcache entry under buffer lock when freeing
- * / rehashing xattr block, checking whether
- * entry is still hashed is reliable.
+ * freeing, rehashing or adding references to
+ * xattr block. Once we hold buffer lock xattr
+ * block's state is stable so we can check
+ * whether the block got freed / rehashed or
+ * not. Since we unhash mbcache entry under
+ * buffer lock when freeing / rehashing xattr
+ * block, checking whether entry is still
+ * hashed is reliable. Same rules hold for
+ * e_reusable handling.
*/
- if (hlist_bl_unhashed(&ce->e_hash_list)) {
+ if (hlist_bl_unhashed(&ce->e_hash_list) ||
+ !ce->e_reusable) {
/*
* Undo everything and check mbcache
* again.
@@ -909,9 +927,12 @@ inserted:
new_bh = NULL;
goto inserted;
}
- le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
+ ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
+ BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
+ if (ref >= EXT4_XATTR_REFCOUNT_MAX)
+ ce->e_reusable = 0;
ea_bdebug(new_bh, "reusing; refcount now=%d",
- le32_to_cpu(BHDR(new_bh)->h_refcount));
+ ref);
unlock_buffer(new_bh);
error = ext4_handle_dirty_xattr_block(handle,
inode,
@@ -1566,11 +1587,14 @@ cleanup:
static void
ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
{
- __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
+ struct ext4_xattr_header *header = BHDR(bh);
+ __u32 hash = le32_to_cpu(header->h_hash);
+ int reusable = le32_to_cpu(header->h_refcount) <
+ EXT4_XATTR_REFCOUNT_MAX;
int error;
error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
- bh->b_blocknr);
+ bh->b_blocknr, reusable);
if (error) {
if (error == -EBUSY)
ea_bdebug(bh, "already in cache");
@@ -1645,12 +1669,6 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
if (!bh) {
EXT4_ERROR_INODE(inode, "block %lu read error",
(unsigned long) ce->e_block);
- } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
- EXT4_XATTR_REFCOUNT_MAX) {
- ea_idebug(inode, "block %lu refcount %d>=%d",
- (unsigned long) ce->e_block,
- le32_to_cpu(BHDR(bh)->h_refcount),
- EXT4_XATTR_REFCOUNT_MAX);
} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
*pce = ce;
return bh;
diff --git a/fs/mbcache.c b/fs/mbcache.c
index 903be151dcfe..eccda3a02de6 100644
--- a/fs/mbcache.c
+++ b/fs/mbcache.c
@@ -63,13 +63,14 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
* @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?
*
* 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.
*/
int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
- sector_t block)
+ sector_t block, bool reusable)
{
struct mb_cache_entry *entry, *dup;
struct hlist_bl_node *dup_node;
@@ -91,6 +92,7 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
atomic_set(&entry->e_refcnt, 1);
entry->e_key = key;
entry->e_block = block;
+ 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) {
@@ -137,7 +139,7 @@ static struct mb_cache_entry *__entry_find(struct mb_cache *cache,
while (node) {
entry = hlist_bl_entry(node, struct mb_cache_entry,
e_hash_list);
- if (entry->e_key == key) {
+ if (entry->e_key == key && entry->e_reusable) {
atomic_inc(&entry->e_refcnt);
goto out;
}
@@ -184,10 +186,38 @@ 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)
+ * @cache - cache we work with
+ * @key - key of block number @block
+ * @block - block number
+ */
+struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
+ sector_t block)
+{
+ struct hlist_bl_node *node;
+ struct hlist_bl_head *head;
+ struct mb_cache_entry *entry;
+
+ 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) {
+ atomic_inc(&entry->e_refcnt);
+ goto out;
+ }
+ }
+ entry = NULL;
+out:
+ hlist_bl_unlock(head);
+ return entry;
+}
+EXPORT_SYMBOL(mb_cache_entry_get);
+
/* mb_cache_entry_delete_block - remove information about block from cache
* @cache - cache we work with
- * @key - key of the entry to remove
- * @block - block containing data for @key
+ * @key - key of block @block
+ * @block - block number
*
* Remove entry from cache @cache with key @key with data stored in @block.
*/
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-02 14:03:33 +0000