ext4: each filesystem creates and uses its own mb_cache

This patch adds new interfaces to create and destory cache,
ext4_xattr_create_cache() and ext4_xattr_destroy_cache(), and remove
the cache creation and destory calls from ex4_init_xattr() and
ext4_exitxattr() in fs/ext4/xattr.c.

fs/ext4/super.c has been changed so that when a filesystem is mounted
a cache is allocated and attched to its ext4_sb_info structure.

fs/mbcache.c has been changed so that only one slab allocator is
allocated and used by all mbcache structures.

Signed-off-by: T. Makphaibulchoke <tmac@hp.com>

1 files changed, 28 insertions, 23 deletions

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 185066f475f1..1f5cf5880718 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -81,7 +81,7 @@
 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
 #endif
 
-static void ext4_xattr_cache_insert(struct buffer_head *);
+static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
                                                  struct ext4_xattr_header *,
                                                  struct mb_cache_entry **);
@@ -90,8 +90,6 @@ static void ext4_xattr_rehash(struct ext4_xattr_header *,
 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
                            size_t buffer_size);
 
-static struct mb_cache *ext4_xattr_cache;
-
 static const struct xattr_handler *ext4_xattr_handler_map[] = {
         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
@@ -117,6 +115,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
         NULL
 };
 
+#define EXT4_GET_MB_CACHE(inode)        (((struct ext4_sb_info *) \
+                                inode->i_sb->s_fs_info)->s_mb_cache)
+
 static __le32 ext4_xattr_block_csum(struct inode *inode,
                                     sector_t block_nr,
                                     struct ext4_xattr_header *hdr)
@@ -265,6 +266,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
         struct ext4_xattr_entry *entry;
         size_t size;
         int error;
+        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
                   name_index, name, buffer, (long)buffer_size);
@@ -286,7 +288,7 @@ bad_block:
                 error = -EIO;
                 goto cleanup;
         }
-        ext4_xattr_cache_insert(bh);
+        ext4_xattr_cache_insert(ext4_mb_cache, bh);
         entry = BFIRST(bh);
         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
         if (error == -EIO)
@@ -409,6 +411,7 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
         struct inode *inode = dentry->d_inode;
         struct buffer_head *bh = NULL;
         int error;
+        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
                   buffer, (long)buffer_size);
@@ -430,7 +433,7 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
                 error = -EIO;
                 goto cleanup;
         }
-        ext4_xattr_cache_insert(bh);
+        ext4_xattr_cache_insert(ext4_mb_cache, bh);
         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 
 cleanup:
@@ -526,8 +529,9 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 {
         struct mb_cache_entry *ce = NULL;
         int error = 0;
+        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
-        ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
+        ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
         error = ext4_journal_get_write_access(handle, bh);
         if (error)
                 goto out;
@@ -746,13 +750,14 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
         struct ext4_xattr_search *s = &bs->s;
         struct mb_cache_entry *ce = NULL;
         int error = 0;
+        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
 #define header(x) ((struct ext4_xattr_header *)(x))
 
         if (i->value && i->value_len > sb->s_blocksize)
                 return -ENOSPC;
         if (s->base) {
-                ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
+                ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
                                         bs->bh->b_blocknr);
                 error = ext4_journal_get_write_access(handle, bs->bh);
                 if (error)
@@ -770,7 +775,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                                 if (!IS_LAST_ENTRY(s->first))
                                         ext4_xattr_rehash(header(s->base),
                                                           s->here);
-                                ext4_xattr_cache_insert(bs->bh);
+                                ext4_xattr_cache_insert(ext4_mb_cache,
+                                        bs->bh);
                         }
                         unlock_buffer(bs->bh);
                         if (error == -EIO)
@@ -906,7 +912,7 @@ getblk_failed:
                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
                         set_buffer_uptodate(new_bh);
                         unlock_buffer(new_bh);
-                        ext4_xattr_cache_insert(new_bh);
+                        ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
                         error = ext4_handle_dirty_xattr_block(handle,
                                                               inode, new_bh);
                         if (error)
@@ -1495,13 +1501,13 @@ ext4_xattr_put_super(struct super_block *sb)
  * Returns 0, or a negative error number on failure.
  */
 static void
-ext4_xattr_cache_insert(struct buffer_head *bh)
+ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
 {
         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
         struct mb_cache_entry *ce;
         int error;
 
-        ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
+        ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
         if (!ce) {
                 ea_bdebug(bh, "out of memory");
                 return;
@@ -1573,12 +1579,13 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 {
         __u32 hash = le32_to_cpu(header->h_hash);
         struct mb_cache_entry *ce;
+        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
         if (!header->h_hash)
                 return NULL;  /* never share */
         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
 again:
-        ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
+        ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
                                        hash);
         while (ce) {
                 struct buffer_head *bh;
@@ -1676,19 +1683,17 @@ static void ext4_xattr_rehash(struct ext4_xattr_header *header,
 
 #undef BLOCK_HASH_SHIFT
 
-int __init
-ext4_init_xattr(void)
+#define HASH_BUCKET_BITS        10
+
+struct mb_cache *
+ext4_xattr_create_cache(char *name)
 {
-        ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
-        if (!ext4_xattr_cache)
-                return -ENOMEM;
-        return 0;
+        return mb_cache_create(name, HASH_BUCKET_BITS);
 }
 
-void
-ext4_exit_xattr(void)
+void ext4_xattr_destroy_cache(struct mb_cache *cache)
 {
-        if (ext4_xattr_cache)
-                mb_cache_destroy(ext4_xattr_cache);
-        ext4_xattr_cache = NULL;
+        if (cache)
+                mb_cache_destroy(cache);
 }
+