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>

5 files changed, 62 insertions, 39 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1b3cbf8cacf9..f4f889e6df83 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1329,6 +1329,7 @@ struct ext4_sb_info {
         struct list_head s_es_lru;
         unsigned long s_es_last_sorted;
         struct percpu_counter s_extent_cache_cnt;
+        struct mb_cache *s_mb_cache;
         spinlock_t s_es_lru_lock ____cacheline_aligned_in_smp;
 
         /* Ratelimit ext4 messages. */
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 89baee42f353..5a51af7d0335 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -59,6 +59,7 @@ static struct kset *ext4_kset;
 static struct ext4_lazy_init *ext4_li_info;
 static struct mutex ext4_li_mtx;
 static struct ext4_features *ext4_feat;
+static int ext4_mballoc_ready;
 
 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
                              unsigned long journal_devnum);
@@ -845,6 +846,10 @@ static void ext4_put_super(struct super_block *sb)
                 invalidate_bdev(sbi->journal_bdev);
                 ext4_blkdev_remove(sbi);
         }
+        if (sbi->s_mb_cache) {
+                ext4_xattr_destroy_cache(sbi->s_mb_cache);
+                sbi->s_mb_cache = NULL;
+        }
         if (sbi->s_mmp_tsk)
                 kthread_stop(sbi->s_mmp_tsk);
         sb->s_fs_info = NULL;
@@ -4010,6 +4015,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
         percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
 
 no_journal:
+        if (ext4_mballoc_ready) {
+                sbi->s_mb_cache = ext4_xattr_create_cache(sb->s_id);
+                if (!sbi->s_mb_cache) {
+                        ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
+                        goto failed_mount_wq;
+                }
+        }
+
         /*
          * Get the # of file system overhead blocks from the
          * superblock if present.
@@ -5519,11 +5532,9 @@ static int __init ext4_init_fs(void)
 
         err = ext4_init_mballoc();
         if (err)
-                goto out3;
-
-        err = ext4_init_xattr();
-        if (err)
                 goto out2;
+        else
+                ext4_mballoc_ready = 1;
         err = init_inodecache();
         if (err)
                 goto out1;
@@ -5539,10 +5550,9 @@ out:
         unregister_as_ext3();
         destroy_inodecache();
 out1:
-        ext4_exit_xattr();
-out2:
+        ext4_mballoc_ready = 0;
         ext4_exit_mballoc();
-out3:
+out2:
         ext4_exit_feat_adverts();
 out4:
         if (ext4_proc_root)
@@ -5565,7 +5575,6 @@ static void __exit ext4_exit_fs(void)
         unregister_as_ext3();
         unregister_filesystem(&ext4_fs_type);
         destroy_inodecache();
-        ext4_exit_xattr();
         ext4_exit_mballoc();
         ext4_exit_feat_adverts();
         remove_proc_entry("fs/ext4", NULL);
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);
 }
+
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 819d6398833f..29bedf5589f6 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -110,9 +110,6 @@ extern void ext4_xattr_put_super(struct super_block *);
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
                             struct ext4_inode *raw_inode, handle_t *handle);
 
-extern int __init ext4_init_xattr(void);
-extern void ext4_exit_xattr(void);
-
 extern const struct xattr_handler *ext4_xattr_handlers[];
 
 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
@@ -124,6 +121,9 @@ extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
                                        struct ext4_xattr_info *i,
                                        struct ext4_xattr_ibody_find *is);
 
+extern struct mb_cache *ext4_xattr_create_cache(char *name);
+extern void ext4_xattr_destroy_cache(struct mb_cache *);
+
 #ifdef CONFIG_EXT4_FS_SECURITY
 extern int ext4_init_security(handle_t *handle, struct inode *inode,
                               struct inode *dir, const struct qstr *qstr);
diff --git a/fs/mbcache.c b/fs/mbcache.c
index 786ecab81c99..bf166e388f0d 100644
--- a/fs/mbcache.c
+++ b/fs/mbcache.c
@@ -99,6 +99,7 @@
 
 static DECLARE_WAIT_QUEUE_HEAD(mb_cache_queue);
 static struct blockgroup_lock *mb_cache_bg_lock;
+static struct kmem_cache *mb_cache_kmem_cache;
 
 MODULE_AUTHOR("Andreas Gruenbacher <a.gruenbacher@computer.org>");
 MODULE_DESCRIPTION("Meta block cache (for extended attributes)");
@@ -351,11 +352,14 @@ mb_cache_create(const char *name, int bucket_bits)
                 goto fail;
         for (n=0; n<bucket_count; n++)
                 INIT_HLIST_BL_HEAD(&cache->c_index_hash[n]);
-        cache->c_entry_cache = kmem_cache_create(name,
-                sizeof(struct mb_cache_entry), 0,
-                SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
-        if (!cache->c_entry_cache)
-                goto fail2;
+        if (!mb_cache_kmem_cache) {
+                mb_cache_kmem_cache = kmem_cache_create(name,
+                        sizeof(struct mb_cache_entry), 0,
+                        SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
+                if (!mb_cache_kmem_cache)
+                        goto fail2;
+        }
+        cache->c_entry_cache = mb_cache_kmem_cache;
 
         /*
          * Set an upper limit on the number of cache entries so that the hash
@@ -476,6 +480,10 @@ mb_cache_destroy(struct mb_cache *cache)
                           atomic_read(&cache->c_entry_count));
         }
 
+        if (list_empty(&mb_cache_list)) {
+                kmem_cache_destroy(mb_cache_kmem_cache);
+                mb_cache_kmem_cache = NULL;
+        }
         kfree(cache->c_index_hash);
         kfree(cache->c_block_hash);
         kfree(cache);