4 files changed, 52 insertions, 0 deletions

diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index 7e2b3ce57aa9..c56300d8d177 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -491,3 +491,30 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
         }
         return 0;
 }
+
+void nilfs_palloc_setup_cache(struct inode *inode,
+                              struct nilfs_palloc_cache *cache)
+{
+        NILFS_MDT(inode)->mi_palloc_cache = cache;
+        spin_lock_init(&cache->lock);
+}
+
+void nilfs_palloc_clear_cache(struct inode *inode)
+{
+        struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+        spin_lock(&cache->lock);
+        brelse(cache->prev_desc.bh);
+        brelse(cache->prev_bitmap.bh);
+        brelse(cache->prev_entry.bh);
+        cache->prev_desc.bh = NULL;
+        cache->prev_bitmap.bh = NULL;
+        cache->prev_entry.bh = NULL;
+        spin_unlock(&cache->lock);
+}
+
+void nilfs_palloc_destroy_cache(struct inode *inode)
+{
+        nilfs_palloc_clear_cache(inode);
+        NILFS_MDT(inode)->mi_palloc_cache = NULL;
+}
diff --git a/fs/nilfs2/alloc.h b/fs/nilfs2/alloc.h
index 4ace5475c2c7..f4543ac4f560 100644
--- a/fs/nilfs2/alloc.h
+++ b/fs/nilfs2/alloc.h
@@ -69,4 +69,25 @@ int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
 #define nilfs_clear_bit_atomic          ext2_clear_bit_atomic
 #define nilfs_find_next_zero_bit        ext2_find_next_zero_bit
 
+/*
+ * persistent object allocator cache
+ */
+
+struct nilfs_bh_assoc {
+        unsigned long blkoff;
+        struct buffer_head *bh;
+};
+
+struct nilfs_palloc_cache {
+        spinlock_t lock;
+        struct nilfs_bh_assoc prev_desc;
+        struct nilfs_bh_assoc prev_bitmap;
+        struct nilfs_bh_assoc prev_entry;
+};
+
+void nilfs_palloc_setup_cache(struct inode *inode,
+                              struct nilfs_palloc_cache *cache);
+void nilfs_palloc_clear_cache(struct inode *inode);
+void nilfs_palloc_destroy_cache(struct inode *inode);
+
 #endif  /* _NILFS_ALLOC_H */
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 948b1f8bc505..06713ffcc7f2 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -571,6 +571,8 @@ void nilfs_mdt_destroy(struct inode *inode)
 {
         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 
+        if (mdi->mi_palloc_cache)
+                nilfs_palloc_destroy_cache(inode);
         nilfs_mdt_clear(inode);
 
         kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
diff --git a/fs/nilfs2/mdt.h b/fs/nilfs2/mdt.h
index c396b6c03931..6c4bbb0470fc 100644
--- a/fs/nilfs2/mdt.h
+++ b/fs/nilfs2/mdt.h
@@ -36,6 +36,7 @@
  * @mi_entry_size: size of an entry
  * @mi_first_entry_offset: offset to the first entry
  * @mi_entries_per_block: number of entries in a block
+ * @mi_palloc_cache: persistent object allocator cache
  * @mi_blocks_per_group: number of blocks in a group
  * @mi_blocks_per_desc_block: number of blocks per descriptor block
  */
@@ -46,6 +47,7 @@ struct nilfs_mdt_info {
         unsigned                mi_entry_size;
         unsigned                mi_first_entry_offset;
         unsigned long           mi_entries_per_block;
+        struct nilfs_palloc_cache *mi_palloc_cache;
         unsigned long           mi_blocks_per_group;
         unsigned long           mi_blocks_per_desc_block;
 };