1 files changed, 85 insertions, 23 deletions

diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index d69e6ae59251..3f959f1879d8 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -142,29 +142,75 @@ static void nilfs_palloc_desc_block_init(struct inode *inode,
         }
 }
 
+static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
+                                  int create,
+                                  void (*init_block)(struct inode *,
+                                                     struct buffer_head *,
+                                                     void *),
+                                  struct buffer_head **bhp,
+                                  struct nilfs_bh_assoc *prev,
+                                  spinlock_t *lock)
+{
+        int ret;
+
+        spin_lock(lock);
+        if (prev->bh && blkoff == prev->blkoff) {
+                get_bh(prev->bh);
+                *bhp = prev->bh;
+                spin_unlock(lock);
+                return 0;
+        }
+        spin_unlock(lock);
+
+        ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
+        if (!ret) {
+                spin_lock(lock);
+                /*
+                 * The following code must be safe for change of the
+                 * cache contents during the get block call.
+                 */
+                brelse(prev->bh);
+                get_bh(*bhp);
+                prev->bh = *bhp;
+                prev->blkoff = blkoff;
+                spin_unlock(lock);
+        }
+        return ret;
+}
+
 static int nilfs_palloc_get_desc_block(struct inode *inode,
                                        unsigned long group,
                                        int create, struct buffer_head **bhp)
 {
-        return nilfs_mdt_get_block(inode,
-                                   nilfs_palloc_desc_blkoff(inode, group),
-                                   create, nilfs_palloc_desc_block_init, bhp);
+        struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+        return nilfs_palloc_get_block(inode,
+                                      nilfs_palloc_desc_blkoff(inode, group),
+                                      create, nilfs_palloc_desc_block_init,
+                                      bhp, &cache->prev_desc, &cache->lock);
 }
 
 static int nilfs_palloc_get_bitmap_block(struct inode *inode,
                                          unsigned long group,
                                          int create, struct buffer_head **bhp)
 {
-        return nilfs_mdt_get_block(inode,
-                                   nilfs_palloc_bitmap_blkoff(inode, group),
-                                   create, NULL, bhp);
+        struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+        return nilfs_palloc_get_block(inode,
+                                      nilfs_palloc_bitmap_blkoff(inode, group),
+                                      create, NULL, bhp,
+                                      &cache->prev_bitmap, &cache->lock);
 }
 
 int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
                                  int create, struct buffer_head **bhp)
 {
-        return nilfs_mdt_get_block(inode, nilfs_palloc_entry_blkoff(inode, nr),
-                                   create, NULL, bhp);
+        struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
+
+        return nilfs_palloc_get_block(inode,
+                                      nilfs_palloc_entry_blkoff(inode, nr),
+                                      create, NULL, bhp,
+                                      &cache->prev_entry, &cache->lock);
 }
 
 static struct nilfs_palloc_group_desc *
@@ -176,13 +222,6 @@ nilfs_palloc_block_get_group_desc(const struct inode *inode,
                 group % nilfs_palloc_groups_per_desc_block(inode);
 }
 
-static unsigned char *
-nilfs_palloc_block_get_bitmap(const struct inode *inode,
-                              const struct buffer_head *bh, void *kaddr)
-{
-        return (unsigned char *)(kaddr + bh_offset(bh));
-}
-
 void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
                                    const struct buffer_head *bh, void *kaddr)
 {
@@ -289,8 +328,7 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
                                 if (ret < 0)
                                         goto out_desc;
                                 bitmap_kaddr = kmap(bitmap_bh->b_page);
-                                bitmap = nilfs_palloc_block_get_bitmap(
-                                        inode, bitmap_bh, bitmap_kaddr);
+                                bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
                                 pos = nilfs_palloc_find_available_slot(
                                         inode, group, group_offset, bitmap,
                                         entries_per_group);
@@ -351,8 +389,7 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
         desc = nilfs_palloc_block_get_group_desc(inode, group,
                                                  req->pr_desc_bh, desc_kaddr);
         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
-        bitmap = nilfs_palloc_block_get_bitmap(inode, req->pr_bitmap_bh,
-                                               bitmap_kaddr);
+        bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
 
         if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
                                     group_offset, bitmap))
@@ -385,8 +422,7 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
         desc = nilfs_palloc_block_get_group_desc(inode, group,
                                                  req->pr_desc_bh, desc_kaddr);
         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
-        bitmap = nilfs_palloc_block_get_bitmap(inode, req->pr_bitmap_bh,
-                                               bitmap_kaddr);
+        bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
         if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
                                     group_offset, bitmap))
                 printk(KERN_WARNING "%s: entry numer %llu already freed\n",
@@ -472,8 +508,7 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
                 desc = nilfs_palloc_block_get_group_desc(
                         inode, group, desc_bh, desc_kaddr);
                 bitmap_kaddr = kmap(bitmap_bh->b_page);
-                bitmap = nilfs_palloc_block_get_bitmap(
-                        inode, bitmap_bh, bitmap_kaddr);
+                bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
                 for (j = i, n = 0;
                      (j < nitems) && nilfs_palloc_group_is_in(inode, group,
                                                               entry_nrs[j]);
@@ -502,3 +537,30 @@ 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;
+}