1 files changed, 295 insertions, 330 deletions

diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index aa412724b64e..e25b507a474f 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -71,21 +71,17 @@ void nilfs_btree_path_cache_destroy(void)
         kmem_cache_destroy(nilfs_btree_path_cache);
 }
 
-static inline struct nilfs_btree_path *
-nilfs_btree_alloc_path(const struct nilfs_btree *btree)
+static inline struct nilfs_btree_path *nilfs_btree_alloc_path(void)
 {
-        return (struct nilfs_btree_path *)
-                kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
+        return kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
 }
 
-static inline void nilfs_btree_free_path(const struct nilfs_btree *btree,
-                                         struct nilfs_btree_path *path)
+static inline void nilfs_btree_free_path(struct nilfs_btree_path *path)
 {
         kmem_cache_free(nilfs_btree_path_cache, path);
 }
 
-static void nilfs_btree_init_path(const struct nilfs_btree *btree,
-                                  struct nilfs_btree_path *path)
+static void nilfs_btree_init_path(struct nilfs_btree_path *path)
 {
         int level;
 
@@ -101,26 +97,13 @@ static void nilfs_btree_init_path(const struct nilfs_btree *btree,
         }
 }
 
-static void nilfs_btree_clear_path(const struct nilfs_btree *btree,
-                                   struct nilfs_btree_path *path)
+static void nilfs_btree_release_path(struct nilfs_btree_path *path)
 {
         int level;
 
-        for (level = NILFS_BTREE_LEVEL_DATA;
-             level < NILFS_BTREE_LEVEL_MAX;
-             level++) {
-                if (path[level].bp_bh != NULL) {
-                        brelse(path[level].bp_bh);
-                        path[level].bp_bh = NULL;
-                }
-                /* sib_bh is released or deleted by prepare or commit
-                 * operations. */
-                path[level].bp_sib_bh = NULL;
-                path[level].bp_index = 0;
-                path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
-                path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
-                path[level].bp_op = NULL;
-        }
+        for (level = NILFS_BTREE_LEVEL_DATA; level < NILFS_BTREE_LEVEL_MAX;
+             level++)
+                brelse(path[level].bp_bh);
 }
 
 /*
@@ -148,129 +131,110 @@ static int nilfs_btree_get_new_block(const struct nilfs_btree *btree,
 }
 
 static inline int
-nilfs_btree_node_get_flags(const struct nilfs_btree *btree,
-                           const struct nilfs_btree_node *node)
+nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
 {
         return node->bn_flags;
 }
 
 static inline void
-nilfs_btree_node_set_flags(struct nilfs_btree *btree,
-                           struct nilfs_btree_node *node,
-                           int flags)
+nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
 {
         node->bn_flags = flags;
 }
 
-static inline int nilfs_btree_node_root(const struct nilfs_btree *btree,
-                                        const struct nilfs_btree_node *node)
+static inline int nilfs_btree_node_root(const struct nilfs_btree_node *node)
 {
-        return nilfs_btree_node_get_flags(btree, node) & NILFS_BTREE_NODE_ROOT;
+        return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
 }
 
 static inline int
-nilfs_btree_node_get_level(const struct nilfs_btree *btree,
-                           const struct nilfs_btree_node *node)
+nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
 {
         return node->bn_level;
 }
 
 static inline void
-nilfs_btree_node_set_level(struct nilfs_btree *btree,
-                           struct nilfs_btree_node *node,
-                           int level)
+nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
 {
         node->bn_level = level;
 }
 
 static inline int
-nilfs_btree_node_get_nchildren(const struct nilfs_btree *btree,
-                               const struct nilfs_btree_node *node)
+nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
 {
         return le16_to_cpu(node->bn_nchildren);
 }
 
 static inline void
-nilfs_btree_node_set_nchildren(struct nilfs_btree *btree,
-                               struct nilfs_btree_node *node,
-                               int nchildren)
+nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 {
         node->bn_nchildren = cpu_to_le16(nchildren);
 }
 
-static inline int
-nilfs_btree_node_size(const struct nilfs_btree *btree)
+static inline int nilfs_btree_node_size(const struct nilfs_btree *btree)
 {
         return 1 << btree->bt_bmap.b_inode->i_blkbits;
 }
 
 static inline int
-nilfs_btree_node_nchildren_min(const struct nilfs_btree *btree,
-                               const struct nilfs_btree_node *node)
+nilfs_btree_node_nchildren_min(const struct nilfs_btree_node *node,
+                               const struct nilfs_btree *btree)
 {
-        return nilfs_btree_node_root(btree, node) ?
+        return nilfs_btree_node_root(node) ?
                 NILFS_BTREE_ROOT_NCHILDREN_MIN :
                 NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
 }
 
 static inline int
-nilfs_btree_node_nchildren_max(const struct nilfs_btree *btree,
-                               const struct nilfs_btree_node *node)
+nilfs_btree_node_nchildren_max(const struct nilfs_btree_node *node,
+                               const struct nilfs_btree *btree)
 {
-        return nilfs_btree_node_root(btree, node) ?
+        return nilfs_btree_node_root(node) ?
                 NILFS_BTREE_ROOT_NCHILDREN_MAX :
                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(btree));
 }
 
 static inline __le64 *
-nilfs_btree_node_dkeys(const struct nilfs_btree *btree,
-                       const struct nilfs_btree_node *node)
+nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
 {
         return (__le64 *)((char *)(node + 1) +
-                          (nilfs_btree_node_root(btree, node) ?
+                          (nilfs_btree_node_root(node) ?
                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
 }
 
 static inline __le64 *
-nilfs_btree_node_dptrs(const struct nilfs_btree *btree,
-                       const struct nilfs_btree_node *node)
+nilfs_btree_node_dptrs(const struct nilfs_btree_node *node,
+                       const struct nilfs_btree *btree)
 {
-        return (__le64 *)(nilfs_btree_node_dkeys(btree, node) +
-                          nilfs_btree_node_nchildren_max(btree, node));
+        return (__le64 *)(nilfs_btree_node_dkeys(node) +
+                          nilfs_btree_node_nchildren_max(node, btree));
 }
 
 static inline __u64
-nilfs_btree_node_get_key(const struct nilfs_btree *btree,
-                         const struct nilfs_btree_node *node, int index)
+nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
 {
-        return nilfs_bmap_dkey_to_key(*(nilfs_btree_node_dkeys(btree, node) +
-                                        index));
+        return nilfs_bmap_dkey_to_key(*(nilfs_btree_node_dkeys(node) + index));
 }
 
 static inline void
-nilfs_btree_node_set_key(struct nilfs_btree *btree,
-                         struct nilfs_btree_node *node, int index, __u64 key)
+nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
 {
-        *(nilfs_btree_node_dkeys(btree, node) + index) =
-                nilfs_bmap_key_to_dkey(key);
+        *(nilfs_btree_node_dkeys(node) + index) = nilfs_bmap_key_to_dkey(key);
 }
 
 static inline __u64
 nilfs_btree_node_get_ptr(const struct nilfs_btree *btree,
-                         const struct nilfs_btree_node *node,
-                         int index)
+                         const struct nilfs_btree_node *node, int index)
 {
-        return nilfs_bmap_dptr_to_ptr(*(nilfs_btree_node_dptrs(btree, node) +
+        return nilfs_bmap_dptr_to_ptr(*(nilfs_btree_node_dptrs(node, btree) +
                                         index));
 }
 
 static inline void
 nilfs_btree_node_set_ptr(struct nilfs_btree *btree,
-                         struct nilfs_btree_node *node,
-                         int index,
-                         __u64 ptr)
+                         struct nilfs_btree_node *node, int index, __u64 ptr)
 {
-        *(nilfs_btree_node_dptrs(btree, node) + index) =
+        *(nilfs_btree_node_dptrs(node, btree) + index) =
                 nilfs_bmap_ptr_to_dptr(ptr);
 }
 
@@ -283,12 +247,12 @@ static void nilfs_btree_node_init(struct nilfs_btree *btree,
         __le64 *dptrs;
         int i;
 
-        nilfs_btree_node_set_flags(btree, node, flags);
-        nilfs_btree_node_set_level(btree, node, level);
-        nilfs_btree_node_set_nchildren(btree, node, nchildren);
+        nilfs_btree_node_set_flags(node, flags);
+        nilfs_btree_node_set_level(node, level);
+        nilfs_btree_node_set_nchildren(node, nchildren);
 
-        dkeys = nilfs_btree_node_dkeys(btree, node);
-        dptrs = nilfs_btree_node_dptrs(btree, node);
+        dkeys = nilfs_btree_node_dkeys(node);
+        dptrs = nilfs_btree_node_dptrs(node, btree);
         for (i = 0; i < nchildren; i++) {
                 dkeys[i] = nilfs_bmap_key_to_dkey(keys[i]);
                 dptrs[i] = nilfs_bmap_ptr_to_dptr(ptrs[i]);
@@ -305,13 +269,13 @@ static void nilfs_btree_node_move_left(struct nilfs_btree *btree,
         __le64 *ldptrs, *rdptrs;
         int lnchildren, rnchildren;
 
-        ldkeys = nilfs_btree_node_dkeys(btree, left);
-        ldptrs = nilfs_btree_node_dptrs(btree, left);
-        lnchildren = nilfs_btree_node_get_nchildren(btree, left);
+        ldkeys = nilfs_btree_node_dkeys(left);
+        ldptrs = nilfs_btree_node_dptrs(left, btree);
+        lnchildren = nilfs_btree_node_get_nchildren(left);
 
-        rdkeys = nilfs_btree_node_dkeys(btree, right);
-        rdptrs = nilfs_btree_node_dptrs(btree, right);
-        rnchildren = nilfs_btree_node_get_nchildren(btree, right);
+        rdkeys = nilfs_btree_node_dkeys(right);
+        rdptrs = nilfs_btree_node_dptrs(right, btree);
+        rnchildren = nilfs_btree_node_get_nchildren(right);
 
         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
@@ -320,8 +284,8 @@ static void nilfs_btree_node_move_left(struct nilfs_btree *btree,
 
         lnchildren += n;
         rnchildren -= n;
-        nilfs_btree_node_set_nchildren(btree, left, lnchildren);
-        nilfs_btree_node_set_nchildren(btree, right, rnchildren);
+        nilfs_btree_node_set_nchildren(left, lnchildren);
+        nilfs_btree_node_set_nchildren(right, rnchildren);
 }
 
 /* Assume that the buffer heads corresponding to left and right are locked. */
@@ -334,13 +298,13 @@ static void nilfs_btree_node_move_right(struct nilfs_btree *btree,
         __le64 *ldptrs, *rdptrs;
         int lnchildren, rnchildren;
 
-        ldkeys = nilfs_btree_node_dkeys(btree, left);
-        ldptrs = nilfs_btree_node_dptrs(btree, left);
-        lnchildren = nilfs_btree_node_get_nchildren(btree, left);
+        ldkeys = nilfs_btree_node_dkeys(left);
+        ldptrs = nilfs_btree_node_dptrs(left, btree);
+        lnchildren = nilfs_btree_node_get_nchildren(left);
 
-        rdkeys = nilfs_btree_node_dkeys(btree, right);
-        rdptrs = nilfs_btree_node_dptrs(btree, right);
-        rnchildren = nilfs_btree_node_get_nchildren(btree, right);
+        rdkeys = nilfs_btree_node_dkeys(right);
+        rdptrs = nilfs_btree_node_dptrs(right, btree);
+        rnchildren = nilfs_btree_node_get_nchildren(right);
 
         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
@@ -349,8 +313,8 @@ static void nilfs_btree_node_move_right(struct nilfs_btree *btree,
 
         lnchildren -= n;
         rnchildren += n;
-        nilfs_btree_node_set_nchildren(btree, left, lnchildren);
-        nilfs_btree_node_set_nchildren(btree, right, rnchildren);
+        nilfs_btree_node_set_nchildren(left, lnchildren);
+        nilfs_btree_node_set_nchildren(right, rnchildren);
 }
 
 /* Assume that the buffer head corresponding to node is locked. */
@@ -362,9 +326,9 @@ static void nilfs_btree_node_insert(struct nilfs_btree *btree,
         __le64 *dptrs;
         int nchildren;
 
-        dkeys = nilfs_btree_node_dkeys(btree, node);
-        dptrs = nilfs_btree_node_dptrs(btree, node);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
+        dkeys = nilfs_btree_node_dkeys(node);
+        dptrs = nilfs_btree_node_dptrs(node, btree);
+        nchildren = nilfs_btree_node_get_nchildren(node);
         if (index < nchildren) {
                 memmove(dkeys + index + 1, dkeys + index,
                         (nchildren - index) * sizeof(*dkeys));
@@ -374,7 +338,7 @@ static void nilfs_btree_node_insert(struct nilfs_btree *btree,
         dkeys[index] = nilfs_bmap_key_to_dkey(key);
         dptrs[index] = nilfs_bmap_ptr_to_dptr(ptr);
         nchildren++;
-        nilfs_btree_node_set_nchildren(btree, node, nchildren);
+        nilfs_btree_node_set_nchildren(node, nchildren);
 }
 
 /* Assume that the buffer head corresponding to node is locked. */
@@ -388,11 +352,11 @@ static void nilfs_btree_node_delete(struct nilfs_btree *btree,
         __le64 *dptrs;
         int nchildren;
 
-        dkeys = nilfs_btree_node_dkeys(btree, node);
-        dptrs = nilfs_btree_node_dptrs(btree, node);
+        dkeys = nilfs_btree_node_dkeys(node);
+        dptrs = nilfs_btree_node_dptrs(node, btree);
         key = nilfs_bmap_dkey_to_key(dkeys[index]);
         ptr = nilfs_bmap_dptr_to_ptr(dptrs[index]);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
+        nchildren = nilfs_btree_node_get_nchildren(node);
         if (keyp != NULL)
                 *keyp = key;
         if (ptrp != NULL)
@@ -405,11 +369,10 @@ static void nilfs_btree_node_delete(struct nilfs_btree *btree,
                         (nchildren - index - 1) * sizeof(*dptrs));
         }
         nchildren--;
-        nilfs_btree_node_set_nchildren(btree, node, nchildren);
+        nilfs_btree_node_set_nchildren(node, nchildren);
 }
 
-static int nilfs_btree_node_lookup(const struct nilfs_btree *btree,
-                                   const struct nilfs_btree_node *node,
+static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
                                    __u64 key, int *indexp)
 {
         __u64 nkey;
@@ -417,12 +380,12 @@ static int nilfs_btree_node_lookup(const struct nilfs_btree *btree,
 
         /* binary search */
         low = 0;
-        high = nilfs_btree_node_get_nchildren(btree, node) - 1;
+        high = nilfs_btree_node_get_nchildren(node) - 1;
         index = 0;
         s = 0;
         while (low <= high) {
                 index = (low + high) / 2;
-                nkey = nilfs_btree_node_get_key(btree, node, index);
+                nkey = nilfs_btree_node_get_key(node, index);
                 if (nkey == key) {
                         s = 0;
                         goto out;
@@ -436,9 +399,8 @@ static int nilfs_btree_node_lookup(const struct nilfs_btree *btree,
         }
 
         /* adjust index */
-        if (nilfs_btree_node_get_level(btree, node) >
-            NILFS_BTREE_LEVEL_NODE_MIN) {
-                if ((s > 0) && (index > 0))
+        if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
+                if (s > 0 && index > 0)
                         index--;
         } else if (s < 0)
                 index++;
@@ -456,25 +418,20 @@ nilfs_btree_get_root(const struct nilfs_btree *btree)
 }
 
 static inline struct nilfs_btree_node *
-nilfs_btree_get_nonroot_node(const struct nilfs_btree *btree,
-                             const struct nilfs_btree_path *path,
-                             int level)
+nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
 {
         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
 }
 
 static inline struct nilfs_btree_node *
-nilfs_btree_get_sib_node(const struct nilfs_btree *btree,
-                         const struct nilfs_btree_path *path,
-                         int level)
+nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
 {
         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
 }
 
 static inline int nilfs_btree_height(const struct nilfs_btree *btree)
 {
-        return nilfs_btree_node_get_level(btree, nilfs_btree_get_root(btree))
-                + 1;
+        return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
 }
 
 static inline struct nilfs_btree_node *
@@ -484,7 +441,7 @@ nilfs_btree_get_node(const struct nilfs_btree *btree,
 {
         return (level == nilfs_btree_height(btree) - 1) ?
                 nilfs_btree_get_root(btree) :
-                nilfs_btree_get_nonroot_node(btree, path, level);
+                nilfs_btree_get_nonroot_node(path, level);
 }
 
 static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
@@ -496,12 +453,11 @@ static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
         int level, index, found, ret;
 
         node = nilfs_btree_get_root(btree);
-        level = nilfs_btree_node_get_level(btree, node);
-        if ((level < minlevel) ||
-            (nilfs_btree_node_get_nchildren(btree, node) <= 0))
+        level = nilfs_btree_node_get_level(node);
+        if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
                 return -ENOENT;
 
-        found = nilfs_btree_node_lookup(btree, node, key, &index);
+        found = nilfs_btree_node_lookup(node, key, &index);
         ptr = nilfs_btree_node_get_ptr(btree, node, index);
         path[level].bp_bh = NULL;
         path[level].bp_index = index;
@@ -510,14 +466,13 @@ static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
                 if (ret < 0)
                         return ret;
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
-                BUG_ON(level != nilfs_btree_node_get_level(btree, node));
+                node = nilfs_btree_get_nonroot_node(path, level);
+                BUG_ON(level != nilfs_btree_node_get_level(node));
                 if (!found)
-                        found = nilfs_btree_node_lookup(btree, node, key,
-                                                        &index);
+                        found = nilfs_btree_node_lookup(node, key, &index);
                 else
                         index = 0;
-                if (index < nilfs_btree_node_nchildren_max(btree, node))
+                if (index < nilfs_btree_node_nchildren_max(node, btree))
                         ptr = nilfs_btree_node_get_ptr(btree, node, index);
                 else {
                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
@@ -544,10 +499,10 @@ static int nilfs_btree_do_lookup_last(const struct nilfs_btree *btree,
         int index, level, ret;
 
         node = nilfs_btree_get_root(btree);
-        index = nilfs_btree_node_get_nchildren(btree, node) - 1;
+        index = nilfs_btree_node_get_nchildren(node) - 1;
         if (index < 0)
                 return -ENOENT;
-        level = nilfs_btree_node_get_level(btree, node);
+        level = nilfs_btree_node_get_level(node);
         ptr = nilfs_btree_node_get_ptr(btree, node, index);
         path[level].bp_bh = NULL;
         path[level].bp_index = index;
@@ -556,15 +511,15 @@ static int nilfs_btree_do_lookup_last(const struct nilfs_btree *btree,
                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
                 if (ret < 0)
                         return ret;
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
-                BUG_ON(level != nilfs_btree_node_get_level(btree, node));
-                index = nilfs_btree_node_get_nchildren(btree, node) - 1;
+                node = nilfs_btree_get_nonroot_node(path, level);
+                BUG_ON(level != nilfs_btree_node_get_level(node));
+                index = nilfs_btree_node_get_nchildren(node) - 1;
                 ptr = nilfs_btree_node_get_ptr(btree, node, index);
                 path[level].bp_index = index;
         }
 
         if (keyp != NULL)
-                *keyp = nilfs_btree_node_get_key(btree, node, index);
+                *keyp = nilfs_btree_node_get_key(node, index);
         if (ptrp != NULL)
                 *ptrp = ptr;
 
@@ -580,18 +535,18 @@ static int nilfs_btree_lookup(const struct nilfs_bmap *bmap,
         int ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);
 
         if (ptrp != NULL)
                 *ptrp = ptr;
 
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
 
         return ret;
 }
@@ -608,10 +563,10 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
         int level = NILFS_BTREE_LEVEL_NODE_MIN;
         int ret, cnt, index, maxlevel;
 
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);
         if (ret < 0)
                 goto out;
@@ -631,8 +586,8 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
         node = nilfs_btree_get_node(btree, path, level);
         index = path[level].bp_index + 1;
         for (;;) {
-                while (index < nilfs_btree_node_get_nchildren(btree, node)) {
-                        if (nilfs_btree_node_get_key(btree, node, index) !=
+                while (index < nilfs_btree_node_get_nchildren(node)) {
+                        if (nilfs_btree_node_get_key(node, index) !=
                             key + cnt)
                                 goto end;
                         ptr2 = nilfs_btree_node_get_ptr(btree, node, index);
@@ -653,8 +608,8 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
                 /* look-up right sibling node */
                 node = nilfs_btree_get_node(btree, path, level + 1);
                 index = path[level + 1].bp_index + 1;
-                if (index >= nilfs_btree_node_get_nchildren(btree, node) ||
-                    nilfs_btree_node_get_key(btree, node, index) != key + cnt)
+                if (index >= nilfs_btree_node_get_nchildren(node) ||
+                    nilfs_btree_node_get_key(node, index) != key + cnt)
                         break;
                 ptr2 = nilfs_btree_node_get_ptr(btree, node, index);
                 path[level + 1].bp_index = index;
@@ -664,7 +619,7 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
                 ret = nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh);
                 if (ret < 0)
                         goto out;
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
+                node = nilfs_btree_get_nonroot_node(path, level);
                 index = 0;
                 path[level].bp_index = index;
         }
@@ -672,8 +627,8 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
         *ptrp = ptr;
         ret = cnt;
  out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
         return ret;
 }
 
@@ -685,9 +640,7 @@ static void nilfs_btree_promote_key(struct nilfs_btree *btree,
                 do {
                         lock_buffer(path[level].bp_bh);
                         nilfs_btree_node_set_key(
-                                btree,
-                                nilfs_btree_get_nonroot_node(
-                                        btree, path, level),
+                                nilfs_btree_get_nonroot_node(path, level),
                                 path[level].bp_index, key);
                         if (!buffer_dirty(path[level].bp_bh))
                                 nilfs_btnode_mark_dirty(path[level].bp_bh);
@@ -698,8 +651,7 @@ static void nilfs_btree_promote_key(struct nilfs_btree *btree,
 
         /* root */
         if (level == nilfs_btree_height(btree) - 1) {
-                nilfs_btree_node_set_key(btree,
-                                         nilfs_btree_get_root(btree),
+                nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
                                          path[level].bp_index, key);
         }
 }
@@ -712,7 +664,7 @@ static void nilfs_btree_do_insert(struct nilfs_btree *btree,
 
         if (level < nilfs_btree_height(btree) - 1) {
                 lock_buffer(path[level].bp_bh);
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
+                node = nilfs_btree_get_nonroot_node(path, level);
                 nilfs_btree_node_insert(btree, node, *keyp, *ptrp,
                                         path[level].bp_index);
                 if (!buffer_dirty(path[level].bp_bh))
@@ -721,8 +673,8 @@ static void nilfs_btree_do_insert(struct nilfs_btree *btree,
 
                 if (path[level].bp_index == 0)
                         nilfs_btree_promote_key(btree, path, level + 1,
-                                                nilfs_btree_node_get_key(
-                                                        btree, node, 0));
+                                                nilfs_btree_node_get_key(node,
+                                                                         0));
         } else {
                 node = nilfs_btree_get_root(btree);
                 nilfs_btree_node_insert(btree, node, *keyp, *ptrp,
@@ -740,10 +692,10 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        left = nilfs_btree_get_sib_node(btree, path, level);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
-        lnchildren = nilfs_btree_node_get_nchildren(btree, left);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        left = nilfs_btree_get_sib_node(path, level);
+        nchildren = nilfs_btree_node_get_nchildren(node);
+        lnchildren = nilfs_btree_node_get_nchildren(left);
         move = 0;
 
         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
@@ -764,7 +716,7 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
         unlock_buffer(path[level].bp_sib_bh);
 
         nilfs_btree_promote_key(btree, path, level + 1,
-                                nilfs_btree_node_get_key(btree, node, 0));
+                                nilfs_btree_node_get_key(node, 0));
 
         if (move) {
                 brelse(path[level].bp_bh);
@@ -791,10 +743,10 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        right = nilfs_btree_get_sib_node(btree, path, level);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
-        rnchildren = nilfs_btree_node_get_nchildren(btree, right);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        right = nilfs_btree_get_sib_node(path, level);
+        nchildren = nilfs_btree_node_get_nchildren(node);
+        rnchildren = nilfs_btree_node_get_nchildren(right);
         move = 0;
 
         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
@@ -816,15 +768,14 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
 
         path[level + 1].bp_index++;
         nilfs_btree_promote_key(btree, path, level + 1,
-                                nilfs_btree_node_get_key(btree, right, 0));
+                                nilfs_btree_node_get_key(right, 0));
         path[level + 1].bp_index--;
 
         if (move) {
                 brelse(path[level].bp_bh);
                 path[level].bp_bh = path[level].bp_sib_bh;
                 path[level].bp_sib_bh = NULL;
-                path[level].bp_index -=
-                        nilfs_btree_node_get_nchildren(btree, node);
+                path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
                 path[level + 1].bp_index++;
         } else {
                 brelse(path[level].bp_sib_bh);
@@ -846,9 +797,9 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        right = nilfs_btree_get_sib_node(btree, path, level);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        right = nilfs_btree_get_sib_node(path, level);
+        nchildren = nilfs_btree_node_get_nchildren(node);
         move = 0;
 
         n = (nchildren + 1) / 2;
@@ -867,16 +818,15 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
         unlock_buffer(path[level].bp_bh);
         unlock_buffer(path[level].bp_sib_bh);
 
-        newkey = nilfs_btree_node_get_key(btree, right, 0);
+        newkey = nilfs_btree_node_get_key(right, 0);
         newptr = path[level].bp_newreq.bpr_ptr;
 
         if (move) {
-                path[level].bp_index -=
-                        nilfs_btree_node_get_nchildren(btree, node);
+                path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
                 nilfs_btree_node_insert(btree, right, *keyp, *ptrp,
                                         path[level].bp_index);
 
-                *keyp = nilfs_btree_node_get_key(btree, right, 0);
+                *keyp = nilfs_btree_node_get_key(right, 0);
                 *ptrp = path[level].bp_newreq.bpr_ptr;
 
                 brelse(path[level].bp_bh);
@@ -885,7 +835,7 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
         } else {
                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 
-                *keyp = nilfs_btree_node_get_key(btree, right, 0);
+                *keyp = nilfs_btree_node_get_key(right, 0);
                 *ptrp = path[level].bp_newreq.bpr_ptr;
 
                 brelse(path[level].bp_sib_bh);
@@ -905,12 +855,12 @@ static void nilfs_btree_grow(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_sib_bh);
 
         root = nilfs_btree_get_root(btree);
-        child = nilfs_btree_get_sib_node(btree, path, level);
+        child = nilfs_btree_get_sib_node(path, level);
 
-        n = nilfs_btree_node_get_nchildren(btree, root);
+        n = nilfs_btree_node_get_nchildren(root);
 
         nilfs_btree_node_move_right(btree, root, child, n);
-        nilfs_btree_node_set_level(btree, root, level + 1);
+        nilfs_btree_node_set_level(root, level + 1);
 
         if (!buffer_dirty(path[level].bp_sib_bh))
                 nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
@@ -922,7 +872,7 @@ static void nilfs_btree_grow(struct nilfs_btree *btree,
 
         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 
-        *keyp = nilfs_btree_node_get_key(btree, child, 0);
+        *keyp = nilfs_btree_node_get_key(child, 0);
         *ptrp = path[level].bp_newreq.bpr_ptr;
 }
 
@@ -990,26 +940,29 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
         struct nilfs_btree_node *node, *parent, *sib;
         __u64 sibptr;
         int pindex, level, ret;
+        struct inode *dat = NULL;
 
         stats->bs_nblocks = 0;
         level = NILFS_BTREE_LEVEL_DATA;
 
         /* allocate a new ptr for data block */
-        if (NILFS_BMAP_USE_VBN(&btree->bt_bmap))
+        if (NILFS_BMAP_USE_VBN(&btree->bt_bmap)) {
                 path[level].bp_newreq.bpr_ptr =
                         nilfs_btree_find_target_v(btree, path, key);
+                dat = nilfs_bmap_get_dat(&btree->bt_bmap);
+        }
 
         ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
-                                           &path[level].bp_newreq);
+                                           &path[level].bp_newreq, dat);
         if (ret < 0)
                 goto err_out_data;
 
         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
              level < nilfs_btree_height(btree) - 1;
              level++) {
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
-                if (nilfs_btree_node_get_nchildren(btree, node) <
-                    nilfs_btree_node_nchildren_max(btree, node)) {
+                node = nilfs_btree_get_nonroot_node(path, level);
+                if (nilfs_btree_node_get_nchildren(node) <
+                    nilfs_btree_node_nchildren_max(node, btree)) {
                         path[level].bp_op = nilfs_btree_do_insert;
                         stats->bs_nblocks++;
                         goto out;
@@ -1026,8 +979,8 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
                         if (ret < 0)
                                 goto err_out_child_node;
                         sib = (struct nilfs_btree_node *)bh->b_data;
-                        if (nilfs_btree_node_get_nchildren(btree, sib) <
-                            nilfs_btree_node_nchildren_max(btree, sib)) {
+                        if (nilfs_btree_node_get_nchildren(sib) <
+                            nilfs_btree_node_nchildren_max(sib, btree)) {
                                 path[level].bp_sib_bh = bh;
                                 path[level].bp_op = nilfs_btree_carry_left;
                                 stats->bs_nblocks++;
@@ -1038,15 +991,15 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 
                 /* right sibling */
                 if (pindex <
-                    nilfs_btree_node_get_nchildren(btree, parent) - 1) {
+                    nilfs_btree_node_get_nchildren(parent) - 1) {
                         sibptr = nilfs_btree_node_get_ptr(btree, parent,
                                                           pindex + 1);
                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
                         if (ret < 0)
                                 goto err_out_child_node;
                         sib = (struct nilfs_btree_node *)bh->b_data;
-                        if (nilfs_btree_node_get_nchildren(btree, sib) <
-                            nilfs_btree_node_nchildren_max(btree, sib)) {
+                        if (nilfs_btree_node_get_nchildren(sib) <
+                            nilfs_btree_node_nchildren_max(sib, btree)) {
                                 path[level].bp_sib_bh = bh;
                                 path[level].bp_op = nilfs_btree_carry_right;
                                 stats->bs_nblocks++;
@@ -1059,7 +1012,7 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
                 path[level].bp_newreq.bpr_ptr =
                         path[level - 1].bp_newreq.bpr_ptr + 1;
                 ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
-                                                   &path[level].bp_newreq);
+                                                   &path[level].bp_newreq, dat);
                 if (ret < 0)
                         goto err_out_child_node;
                 ret = nilfs_btree_get_new_block(btree,
@@ -1081,8 +1034,8 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 
         /* root */
         node = nilfs_btree_get_root(btree);
-        if (nilfs_btree_node_get_nchildren(btree, node) <
-            nilfs_btree_node_nchildren_max(btree, node)) {
+        if (nilfs_btree_node_get_nchildren(node) <
+            nilfs_btree_node_nchildren_max(node, btree)) {
                 path[level].bp_op = nilfs_btree_do_insert;
                 stats->bs_nblocks++;
                 goto out;
@@ -1091,7 +1044,7 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
         /* grow */
         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
         ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
-                                           &path[level].bp_newreq);
+                                           &path[level].bp_newreq, dat);
         if (ret < 0)
                 goto err_out_child_node;
         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
@@ -1119,16 +1072,18 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 
         /* error */
  err_out_curr_node:
-        nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap, &path[level].bp_newreq);
+        nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap, &path[level].bp_newreq,
+                                   dat);
  err_out_child_node:
         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
                 nilfs_btnode_delete(path[level].bp_sib_bh);
                 nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap,
-                                           &path[level].bp_newreq);
+                                           &path[level].bp_newreq, dat);
 
         }
 
-        nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap, &path[level].bp_newreq);
+        nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap, &path[level].bp_newreq,
+                                   dat);
  err_out_data:
         *levelp = level;
         stats->bs_nblocks = 0;
@@ -1139,16 +1094,19 @@ static void nilfs_btree_commit_insert(struct nilfs_btree *btree,
                                       struct nilfs_btree_path *path,
                                       int maxlevel, __u64 key, __u64 ptr)
 {
+        struct inode *dat = NULL;
         int level;
 
         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
-        if (NILFS_BMAP_USE_VBN(&btree->bt_bmap))
+        if (NILFS_BMAP_USE_VBN(&btree->bt_bmap)) {
                 nilfs_btree_set_target_v(btree, key, ptr);
+                dat = nilfs_bmap_get_dat(&btree->bt_bmap);
+        }
 
         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
                 nilfs_bmap_commit_alloc_ptr(&btree->bt_bmap,
-                                            &path[level - 1].bp_newreq);
+                                            &path[level - 1].bp_newreq, dat);
                 path[level].bp_op(btree, path, level, &key, &ptr);
         }
 
@@ -1164,10 +1122,10 @@ static int nilfs_btree_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
         int level, ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
                                     NILFS_BTREE_LEVEL_NODE_MIN);
@@ -1184,8 +1142,8 @@ static int nilfs_btree_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
         nilfs_bmap_add_blocks(bmap, stats.bs_nblocks);
 
  out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
         return ret;
 }
 
@@ -1197,7 +1155,7 @@ static void nilfs_btree_do_delete(struct nilfs_btree *btree,
 
         if (level < nilfs_btree_height(btree) - 1) {
                 lock_buffer(path[level].bp_bh);
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
+                node = nilfs_btree_get_nonroot_node(path, level);
                 nilfs_btree_node_delete(btree, node, keyp, ptrp,
                                         path[level].bp_index);
                 if (!buffer_dirty(path[level].bp_bh))
@@ -1205,7 +1163,7 @@ static void nilfs_btree_do_delete(struct nilfs_btree *btree,
                 unlock_buffer(path[level].bp_bh);
                 if (path[level].bp_index == 0)
                         nilfs_btree_promote_key(btree, path, level + 1,
-                                nilfs_btree_node_get_key(btree, node, 0));
+                                nilfs_btree_node_get_key(node, 0));
         } else {
                 node = nilfs_btree_get_root(btree);
                 nilfs_btree_node_delete(btree, node, keyp, ptrp,
@@ -1225,10 +1183,10 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        left = nilfs_btree_get_sib_node(btree, path, level);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
-        lnchildren = nilfs_btree_node_get_nchildren(btree, left);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        left = nilfs_btree_get_sib_node(path, level);
+        nchildren = nilfs_btree_node_get_nchildren(node);
+        lnchildren = nilfs_btree_node_get_nchildren(left);
 
         n = (nchildren + lnchildren) / 2 - nchildren;
 
@@ -1243,7 +1201,7 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
         unlock_buffer(path[level].bp_sib_bh);
 
         nilfs_btree_promote_key(btree, path, level + 1,
-                                nilfs_btree_node_get_key(btree, node, 0));
+                                nilfs_btree_node_get_key(node, 0));
 
         brelse(path[level].bp_sib_bh);
         path[level].bp_sib_bh = NULL;
@@ -1262,10 +1220,10 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        right = nilfs_btree_get_sib_node(btree, path, level);
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
-        rnchildren = nilfs_btree_node_get_nchildren(btree, right);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        right = nilfs_btree_get_sib_node(path, level);
+        nchildren = nilfs_btree_node_get_nchildren(node);
+        rnchildren = nilfs_btree_node_get_nchildren(right);
 
         n = (nchildren + rnchildren) / 2 - nchildren;
 
@@ -1281,7 +1239,7 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
 
         path[level + 1].bp_index++;
         nilfs_btree_promote_key(btree, path, level + 1,
-                                nilfs_btree_node_get_key(btree, right, 0));
+                                nilfs_btree_node_get_key(right, 0));
         path[level + 1].bp_index--;
 
         brelse(path[level].bp_sib_bh);
@@ -1300,10 +1258,10 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        left = nilfs_btree_get_sib_node(btree, path, level);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        left = nilfs_btree_get_sib_node(path, level);
 
-        n = nilfs_btree_node_get_nchildren(btree, node);
+        n = nilfs_btree_node_get_nchildren(node);
 
         nilfs_btree_node_move_left(btree, left, node, n);
 
@@ -1316,7 +1274,7 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,
         nilfs_btnode_delete(path[level].bp_bh);
         path[level].bp_bh = path[level].bp_sib_bh;
         path[level].bp_sib_bh = NULL;
-        path[level].bp_index += nilfs_btree_node_get_nchildren(btree, left);
+        path[level].bp_index += nilfs_btree_node_get_nchildren(left);
 }
 
 static void nilfs_btree_concat_right(struct nilfs_btree *btree,
@@ -1331,10 +1289,10 @@ static void nilfs_btree_concat_right(struct nilfs_btree *btree,
         lock_buffer(path[level].bp_bh);
         lock_buffer(path[level].bp_sib_bh);
 
-        node = nilfs_btree_get_nonroot_node(btree, path, level);
-        right = nilfs_btree_get_sib_node(btree, path, level);
+        node = nilfs_btree_get_nonroot_node(path, level);
+        right = nilfs_btree_get_sib_node(path, level);
 
-        n = nilfs_btree_node_get_nchildren(btree, right);
+        n = nilfs_btree_node_get_nchildren(right);
 
         nilfs_btree_node_move_left(btree, node, right, n);
 
@@ -1360,11 +1318,11 @@ static void nilfs_btree_shrink(struct nilfs_btree *btree,
 
         lock_buffer(path[level].bp_bh);
         root = nilfs_btree_get_root(btree);
-        child = nilfs_btree_get_nonroot_node(btree, path, level);
+        child = nilfs_btree_get_nonroot_node(path, level);
 
         nilfs_btree_node_delete(btree, root, NULL, NULL, 0);
-        nilfs_btree_node_set_level(btree, root, level);
-        n = nilfs_btree_node_get_nchildren(btree, child);
+        nilfs_btree_node_set_level(root, level);
+        n = nilfs_btree_node_get_nchildren(child);
         nilfs_btree_node_move_left(btree, root, child, n);
         unlock_buffer(path[level].bp_bh);
 
@@ -1376,7 +1334,8 @@ static void nilfs_btree_shrink(struct nilfs_btree *btree,
 static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                                       struct nilfs_btree_path *path,
                                       int *levelp,
-                                      struct nilfs_bmap_stats *stats)
+                                      struct nilfs_bmap_stats *stats,
+                                      struct inode *dat)
 {
         struct buffer_head *bh;
         struct nilfs_btree_node *node, *parent, *sib;
@@ -1388,17 +1347,17 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
              level < nilfs_btree_height(btree) - 1;
              level++) {
-                node = nilfs_btree_get_nonroot_node(btree, path, level);
+                node = nilfs_btree_get_nonroot_node(path, level);
                 path[level].bp_oldreq.bpr_ptr =
                         nilfs_btree_node_get_ptr(btree, node,
                                                  path[level].bp_index);
                 ret = nilfs_bmap_prepare_end_ptr(&btree->bt_bmap,
-                                                 &path[level].bp_oldreq);
+                                                 &path[level].bp_oldreq, dat);
                 if (ret < 0)
                         goto err_out_child_node;
 
-                if (nilfs_btree_node_get_nchildren(btree, node) >
-                    nilfs_btree_node_nchildren_min(btree, node)) {
+                if (nilfs_btree_node_get_nchildren(node) >
+                    nilfs_btree_node_nchildren_min(node, btree)) {
                         path[level].bp_op = nilfs_btree_do_delete;
                         stats->bs_nblocks++;
                         goto out;
@@ -1415,8 +1374,8 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                         if (ret < 0)
                                 goto err_out_curr_node;
                         sib = (struct nilfs_btree_node *)bh->b_data;
-                        if (nilfs_btree_node_get_nchildren(btree, sib) >
-                            nilfs_btree_node_nchildren_min(btree, sib)) {
+                        if (nilfs_btree_node_get_nchildren(sib) >
+                            nilfs_btree_node_nchildren_min(sib, btree)) {
                                 path[level].bp_sib_bh = bh;
                                 path[level].bp_op = nilfs_btree_borrow_left;
                                 stats->bs_nblocks++;
@@ -1428,7 +1387,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                                 /* continue; */
                         }
                 } else if (pindex <
-                           nilfs_btree_node_get_nchildren(btree, parent) - 1) {
+                           nilfs_btree_node_get_nchildren(parent) - 1) {
                         /* right sibling */
                         sibptr = nilfs_btree_node_get_ptr(btree, parent,
                                                           pindex + 1);
@@ -1436,8 +1395,8 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                         if (ret < 0)
                                 goto err_out_curr_node;
                         sib = (struct nilfs_btree_node *)bh->b_data;
-                        if (nilfs_btree_node_get_nchildren(btree, sib) >
-                            nilfs_btree_node_nchildren_min(btree, sib)) {
+                        if (nilfs_btree_node_get_nchildren(sib) >
+                            nilfs_btree_node_nchildren_min(sib, btree)) {
                                 path[level].bp_sib_bh = bh;
                                 path[level].bp_op = nilfs_btree_borrow_right;
                                 stats->bs_nblocks++;
@@ -1452,7 +1411,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                         /* no siblings */
                         /* the only child of the root node */
                         WARN_ON(level != nilfs_btree_height(btree) - 2);
-                        if (nilfs_btree_node_get_nchildren(btree, node) - 1 <=
+                        if (nilfs_btree_node_get_nchildren(node) - 1 <=
                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
                                 path[level].bp_op = nilfs_btree_shrink;
                                 stats->bs_nblocks += 2;
@@ -1471,7 +1430,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
                 nilfs_btree_node_get_ptr(btree, node, path[level].bp_index);
 
         ret = nilfs_bmap_prepare_end_ptr(&btree->bt_bmap,
-                                         &path[level].bp_oldreq);
+                                         &path[level].bp_oldreq, dat);
         if (ret < 0)
                 goto err_out_child_node;
 
@@ -1486,12 +1445,12 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 
         /* error */
  err_out_curr_node:
-        nilfs_bmap_abort_end_ptr(&btree->bt_bmap, &path[level].bp_oldreq);
+        nilfs_bmap_abort_end_ptr(&btree->bt_bmap, &path[level].bp_oldreq, dat);
  err_out_child_node:
         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
                 brelse(path[level].bp_sib_bh);
                 nilfs_bmap_abort_end_ptr(&btree->bt_bmap,
-                                         &path[level].bp_oldreq);
+                                         &path[level].bp_oldreq, dat);
         }
         *levelp = level;
         stats->bs_nblocks = 0;
@@ -1500,13 +1459,13 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 
 static void nilfs_btree_commit_delete(struct nilfs_btree *btree,
                                       struct nilfs_btree_path *path,
-                                      int maxlevel)
+                                      int maxlevel, struct inode *dat)
 {
         int level;
 
         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
                 nilfs_bmap_commit_end_ptr(&btree->bt_bmap,
-                                          &path[level].bp_oldreq);
+                                          &path[level].bp_oldreq, dat);
                 path[level].bp_op(btree, path, level, NULL, NULL);
         }
 
@@ -1520,27 +1479,32 @@ static int nilfs_btree_delete(struct nilfs_bmap *bmap, __u64 key)
         struct nilfs_btree *btree;
         struct nilfs_btree_path *path;
         struct nilfs_bmap_stats stats;
+        struct inode *dat;
         int level, ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
                                     NILFS_BTREE_LEVEL_NODE_MIN);
         if (ret < 0)
                 goto out;
 
-        ret = nilfs_btree_prepare_delete(btree, path, &level, &stats);
+
+        dat = NILFS_BMAP_USE_VBN(&btree->bt_bmap) ?
+                nilfs_bmap_get_dat(&btree->bt_bmap) : NULL;
+
+        ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
         if (ret < 0)
                 goto out;
-        nilfs_btree_commit_delete(btree, path, level);
+        nilfs_btree_commit_delete(btree, path, level, dat);
         nilfs_bmap_sub_blocks(bmap, stats.bs_nblocks);
 
 out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
         return ret;
 }
 
@@ -1551,15 +1515,15 @@ static int nilfs_btree_last_key(const struct nilfs_bmap *bmap, __u64 *keyp)
         int ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
 
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
 
         return ret;
 }
@@ -1581,7 +1545,7 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *bmap, __u64 key)
                 node = root;
                 break;
         case 3:
-                nchildren = nilfs_btree_node_get_nchildren(btree, root);
+                nchildren = nilfs_btree_node_get_nchildren(root);
                 if (nchildren > 1)
                         return 0;
                 ptr = nilfs_btree_node_get_ptr(btree, root, nchildren - 1);
@@ -1594,10 +1558,10 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *bmap, __u64 key)
                 return 0;
         }
 
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
-        maxkey = nilfs_btree_node_get_key(btree, node, nchildren - 1);
+        nchildren = nilfs_btree_node_get_nchildren(node);
+        maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
         nextmaxkey = (nchildren > 1) ?
-                nilfs_btree_node_get_key(btree, node, nchildren - 2) : 0;
+                nilfs_btree_node_get_key(node, nchildren - 2) : 0;
         if (bh != NULL)
                 brelse(bh);
 
@@ -1623,7 +1587,7 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
                 node = root;
                 break;
         case 3:
-                nchildren = nilfs_btree_node_get_nchildren(btree, root);
+                nchildren = nilfs_btree_node_get_nchildren(root);
                 WARN_ON(nchildren > 1);
                 ptr = nilfs_btree_node_get_ptr(btree, root, nchildren - 1);
                 ret = nilfs_btree_get_block(btree, ptr, &bh);
@@ -1636,11 +1600,11 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
                 return -EINVAL;
         }
 
-        nchildren = nilfs_btree_node_get_nchildren(btree, node);
+        nchildren = nilfs_btree_node_get_nchildren(node);
         if (nchildren < nitems)
                 nitems = nchildren;
-        dkeys = nilfs_btree_node_dkeys(btree, node);
-        dptrs = nilfs_btree_node_dptrs(btree, node);
+        dkeys = nilfs_btree_node_dkeys(node);
+        dptrs = nilfs_btree_node_dptrs(node, btree);
         for (i = 0; i < nitems; i++) {
                 keys[i] = nilfs_bmap_dkey_to_key(dkeys[i]);
                 ptrs[i] = nilfs_bmap_dptr_to_ptr(dptrs[i]);
@@ -1660,18 +1624,20 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *bmap, __u64 key,
                                        struct nilfs_bmap_stats *stats)
 {
         struct buffer_head *bh;
-        struct nilfs_btree *btree;
+        struct nilfs_btree *btree = (struct nilfs_btree *)bmap;
+        struct inode *dat = NULL;
         int ret;
 
-        btree = (struct nilfs_btree *)bmap;
         stats->bs_nblocks = 0;
 
         /* for data */
         /* cannot find near ptr */
-        if (NILFS_BMAP_USE_VBN(bmap))
+        if (NILFS_BMAP_USE_VBN(bmap)) {
                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
+                dat = nilfs_bmap_get_dat(bmap);
+        }
 
-        ret = nilfs_bmap_prepare_alloc_ptr(bmap, dreq);
+        ret = nilfs_bmap_prepare_alloc_ptr(bmap, dreq, dat);
         if (ret < 0)
                 return ret;
 
@@ -1679,7 +1645,7 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *bmap, __u64 key,
         stats->bs_nblocks++;
         if (nreq != NULL) {
                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
-                ret = nilfs_bmap_prepare_alloc_ptr(bmap, nreq);
+                ret = nilfs_bmap_prepare_alloc_ptr(bmap, nreq, dat);
                 if (ret < 0)
                         goto err_out_dreq;
 
@@ -1696,9 +1662,9 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *bmap, __u64 key,
 
         /* error */
  err_out_nreq:
-        nilfs_bmap_abort_alloc_ptr(bmap, nreq);
+        nilfs_bmap_abort_alloc_ptr(bmap, nreq, dat);
  err_out_dreq:
-        nilfs_bmap_abort_alloc_ptr(bmap, dreq);
+        nilfs_bmap_abort_alloc_ptr(bmap, dreq, dat);
         stats->bs_nblocks = 0;
         return ret;
 
@@ -1713,8 +1679,9 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
                                       union nilfs_bmap_ptr_req *nreq,
                                       struct buffer_head *bh)
 {
-        struct nilfs_btree *btree;
+        struct nilfs_btree *btree = (struct nilfs_btree *)bmap;
         struct nilfs_btree_node *node;
+        struct inode *dat;
         __u64 tmpptr;
 
         /* free resources */
@@ -1725,11 +1692,11 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
 
         /* convert and insert */
-        btree = (struct nilfs_btree *)bmap;
+        dat = NILFS_BMAP_USE_VBN(bmap) ? nilfs_bmap_get_dat(bmap) : NULL;
         nilfs_btree_init(bmap);
         if (nreq != NULL) {
-                nilfs_bmap_commit_alloc_ptr(bmap, dreq);
-                nilfs_bmap_commit_alloc_ptr(bmap, nreq);
+                nilfs_bmap_commit_alloc_ptr(bmap, dreq, dat);
+                nilfs_bmap_commit_alloc_ptr(bmap, nreq, dat);
 
                 /* create child node at level 1 */
                 lock_buffer(bh);
@@ -1751,7 +1718,7 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
                 nilfs_btree_node_init(btree, node, NILFS_BTREE_NODE_ROOT,
                                       2, 1, &keys[0], &tmpptr);
         } else {
-                nilfs_bmap_commit_alloc_ptr(bmap, dreq);
+                nilfs_bmap_commit_alloc_ptr(bmap, dreq, dat);
 
                 /* create root node at level 1 */
                 node = nilfs_btree_get_root(btree);
@@ -1822,7 +1789,7 @@ static int nilfs_btree_propagate_p(struct nilfs_btree *btree,
 
 static int nilfs_btree_prepare_update_v(struct nilfs_btree *btree,
                                         struct nilfs_btree_path *path,
-                                        int level)
+                                        int level, struct inode *dat)
 {
         struct nilfs_btree_node *parent;
         int ret;
@@ -1832,9 +1799,8 @@ static int nilfs_btree_prepare_update_v(struct nilfs_btree *btree,
                 nilfs_btree_node_get_ptr(btree, parent,
                                          path[level + 1].bp_index);
         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
-        ret = nilfs_bmap_prepare_update_v(&btree->bt_bmap,
-                                          &path[level].bp_oldreq,
-                                          &path[level].bp_newreq);
+        ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
+                                       &path[level].bp_newreq.bpr_req);
         if (ret < 0)
                 return ret;
 
@@ -1846,9 +1812,9 @@ static int nilfs_btree_prepare_update_v(struct nilfs_btree *btree,
                         &NILFS_BMAP_I(&btree->bt_bmap)->i_btnode_cache,
                         &path[level].bp_ctxt);
                 if (ret < 0) {
-                        nilfs_bmap_abort_update_v(&btree->bt_bmap,
-                                                  &path[level].bp_oldreq,
-                                                  &path[level].bp_newreq);
+                        nilfs_dat_abort_update(dat,
+                                               &path[level].bp_oldreq.bpr_req,
+                                               &path[level].bp_newreq.bpr_req);
                         return ret;
                 }
         }
@@ -1858,13 +1824,13 @@ static int nilfs_btree_prepare_update_v(struct nilfs_btree *btree,
 
 static void nilfs_btree_commit_update_v(struct nilfs_btree *btree,
                                         struct nilfs_btree_path *path,
-                                        int level)
+                                        int level, struct inode *dat)
 {
         struct nilfs_btree_node *parent;
 
-        nilfs_bmap_commit_update_v(&btree->bt_bmap,
-                                   &path[level].bp_oldreq,
-                                   &path[level].bp_newreq);
+        nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
+                                &path[level].bp_newreq.bpr_req,
+                                btree->bt_bmap.b_ptr_type == NILFS_BMAP_PTR_VS);
 
         if (buffer_nilfs_node(path[level].bp_bh)) {
                 nilfs_btnode_commit_change_key(
@@ -1881,11 +1847,10 @@ static void nilfs_btree_commit_update_v(struct nilfs_btree *btree,
 
 static void nilfs_btree_abort_update_v(struct nilfs_btree *btree,
                                        struct nilfs_btree_path *path,
-                                       int level)
+                                       int level, struct inode *dat)
 {
-        nilfs_bmap_abort_update_v(&btree->bt_bmap,
-                                  &path[level].bp_oldreq,
-                                  &path[level].bp_newreq);
+        nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
+                               &path[level].bp_newreq.bpr_req);
         if (buffer_nilfs_node(path[level].bp_bh))
                 nilfs_btnode_abort_change_key(
                         &NILFS_BMAP_I(&btree->bt_bmap)->i_btnode_cache,
@@ -1894,14 +1859,14 @@ static void nilfs_btree_abort_update_v(struct nilfs_btree *btree,
 
 static int nilfs_btree_prepare_propagate_v(struct nilfs_btree *btree,
                                            struct nilfs_btree_path *path,
-                                           int minlevel,
-                                           int *maxlevelp)
+                                           int minlevel, int *maxlevelp,
+                                           struct inode *dat)
 {
         int level, ret;
 
         level = minlevel;
         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
-                ret = nilfs_btree_prepare_update_v(btree, path, level);
+                ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
                 if (ret < 0)
                         return ret;
         }
@@ -1909,7 +1874,7 @@ static int nilfs_btree_prepare_propagate_v(struct nilfs_btree *btree,
                !buffer_dirty(path[level].bp_bh)) {
 
                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
-                ret = nilfs_btree_prepare_update_v(btree, path, level);
+                ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
                 if (ret < 0)
                         goto out;
         }
@@ -1921,39 +1886,40 @@ static int nilfs_btree_prepare_propagate_v(struct nilfs_btree *btree,
         /* error */
  out:
         while (--level > minlevel)
-                nilfs_btree_abort_update_v(btree, path, level);
+                nilfs_btree_abort_update_v(btree, path, level, dat);
         if (!buffer_nilfs_volatile(path[level].bp_bh))
-                nilfs_btree_abort_update_v(btree, path, level);
+                nilfs_btree_abort_update_v(btree, path, level, dat);
         return ret;
 }
 
 static void nilfs_btree_commit_propagate_v(struct nilfs_btree *btree,
                                            struct nilfs_btree_path *path,
-                                           int minlevel,
-                                           int maxlevel,
-                                           struct buffer_head *bh)
+                                           int minlevel, int maxlevel,
+                                           struct buffer_head *bh,
+                                           struct inode *dat)
 {
         int level;
 
         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
-                nilfs_btree_commit_update_v(btree, path, minlevel);
+                nilfs_btree_commit_update_v(btree, path, minlevel, dat);
 
         for (level = minlevel + 1; level <= maxlevel; level++)
-                nilfs_btree_commit_update_v(btree, path, level);
+                nilfs_btree_commit_update_v(btree, path, level, dat);
 }
 
 static int nilfs_btree_propagate_v(struct nilfs_btree *btree,
                                    struct nilfs_btree_path *path,
-                                   int level,
-                                   struct buffer_head *bh)
+                                   int level, struct buffer_head *bh)
 {
         int maxlevel, ret;
         struct nilfs_btree_node *parent;
+        struct inode *dat = nilfs_bmap_get_dat(&btree->bt_bmap);
         __u64 ptr;
 
         get_bh(bh);
         path[level].bp_bh = bh;
-        ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel);
+        ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
+                                              dat);
         if (ret < 0)
                 goto out;
 
@@ -1961,12 +1927,12 @@ static int nilfs_btree_propagate_v(struct nilfs_btree *btree,
                 parent = nilfs_btree_get_node(btree, path, level + 1);
                 ptr = nilfs_btree_node_get_ptr(btree, parent,
                                                path[level + 1].bp_index);
-                ret = nilfs_bmap_mark_dirty(&btree->bt_bmap, ptr);
+                ret = nilfs_dat_mark_dirty(dat, ptr);
                 if (ret < 0)
                         goto out;
         }
 
-        nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh);
+        nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
 
  out:
         brelse(path[level].bp_bh);
@@ -1986,15 +1952,15 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
         WARN_ON(!buffer_dirty(bh));
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         if (buffer_nilfs_node(bh)) {
                 node = (struct nilfs_btree_node *)bh->b_data;
-                key = nilfs_btree_node_get_key(btree, node, 0);
-                level = nilfs_btree_node_get_level(btree, node);
+                key = nilfs_btree_node_get_key(node, 0);
+                level = nilfs_btree_node_get_level(node);
         } else {
                 key = nilfs_bmap_data_get_key(bmap, bh);
                 level = NILFS_BTREE_LEVEL_DATA;
@@ -2013,8 +1979,8 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
                 nilfs_btree_propagate_p(btree, path, level, bh);
 
  out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
 
         return ret;
 }
@@ -2022,7 +1988,7 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
 static int nilfs_btree_propagate_gc(const struct nilfs_bmap *bmap,
                                     struct buffer_head *bh)
 {
-        return nilfs_bmap_mark_dirty(bmap, bh->b_blocknr);
+        return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(bmap), bh->b_blocknr);
 }
 
 static void nilfs_btree_add_dirty_buffer(struct nilfs_btree *btree,
@@ -2037,12 +2003,12 @@ static void nilfs_btree_add_dirty_buffer(struct nilfs_btree *btree,
 
         get_bh(bh);
         node = (struct nilfs_btree_node *)bh->b_data;
-        key = nilfs_btree_node_get_key(btree, node, 0);
-        level = nilfs_btree_node_get_level(btree, node);
+        key = nilfs_btree_node_get_key(node, 0);
+        level = nilfs_btree_node_get_level(node);
         list_for_each(head, &lists[level]) {
                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
                 cnode = (struct nilfs_btree_node *)cbh->b_data;
-                ckey = nilfs_btree_node_get_key(btree, cnode, 0);
+                ckey = nilfs_btree_node_get_key(cnode, 0);
                 if (key < ckey)
                         break;
         }
@@ -2120,8 +2086,7 @@ static int nilfs_btree_assign_p(struct nilfs_btree *btree,
         nilfs_btree_node_set_ptr(btree, parent,
                                  path[level + 1].bp_index, blocknr);
 
-        key = nilfs_btree_node_get_key(btree, parent,
-                                       path[level + 1].bp_index);
+        key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
         /* on-disk format */
         binfo->bi_dat.bi_blkoff = nilfs_bmap_key_to_dkey(key);
         binfo->bi_dat.bi_level = level;
@@ -2137,6 +2102,7 @@ static int nilfs_btree_assign_v(struct nilfs_btree *btree,
                                 union nilfs_binfo *binfo)
 {
         struct nilfs_btree_node *parent;
+        struct inode *dat = nilfs_bmap_get_dat(&btree->bt_bmap);
         __u64 key;
         __u64 ptr;
         union nilfs_bmap_ptr_req req;
@@ -2146,12 +2112,12 @@ static int nilfs_btree_assign_v(struct nilfs_btree *btree,
         ptr = nilfs_btree_node_get_ptr(btree, parent,
                                        path[level + 1].bp_index);
         req.bpr_ptr = ptr;
-        ret = nilfs_bmap_start_v(&btree->bt_bmap, &req, blocknr);
-        if (unlikely(ret < 0))
+        ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
+        if (ret < 0)
                 return ret;
+        nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
 
-        key = nilfs_btree_node_get_key(btree, parent,
-                                       path[level + 1].bp_index);
+        key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
         /* on-disk format */
         binfo->bi_v.bi_vblocknr = nilfs_bmap_ptr_to_dptr(ptr);
         binfo->bi_v.bi_blkoff = nilfs_bmap_key_to_dkey(key);
@@ -2171,15 +2137,15 @@ static int nilfs_btree_assign(struct nilfs_bmap *bmap,
         int level, ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         if (buffer_nilfs_node(*bh)) {
                 node = (struct nilfs_btree_node *)(*bh)->b_data;
-                key = nilfs_btree_node_get_key(btree, node, 0);
-                level = nilfs_btree_node_get_level(btree, node);
+                key = nilfs_btree_node_get_key(node, 0);
+                level = nilfs_btree_node_get_level(node);
         } else {
                 key = nilfs_bmap_data_get_key(bmap, *bh);
                 level = NILFS_BTREE_LEVEL_DATA;
@@ -2196,8 +2162,8 @@ static int nilfs_btree_assign(struct nilfs_bmap *bmap,
                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
 
  out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
 
         return ret;
 }
@@ -2207,19 +2173,18 @@ static int nilfs_btree_assign_gc(struct nilfs_bmap *bmap,
                                  sector_t blocknr,
                                  union nilfs_binfo *binfo)
 {
-        struct nilfs_btree *btree;
         struct nilfs_btree_node *node;
         __u64 key;
         int ret;
 
-        btree = (struct nilfs_btree *)bmap;
-        ret = nilfs_bmap_move_v(bmap, (*bh)->b_blocknr, blocknr);
+        ret = nilfs_dat_move(nilfs_bmap_get_dat(bmap), (*bh)->b_blocknr,
+                             blocknr);
         if (ret < 0)
                 return ret;
 
         if (buffer_nilfs_node(*bh)) {
                 node = (struct nilfs_btree_node *)(*bh)->b_data;
-                key = nilfs_btree_node_get_key(btree, node, 0);
+                key = nilfs_btree_node_get_key(node, 0);
         } else
                 key = nilfs_bmap_data_get_key(bmap, *bh);
 
@@ -2239,10 +2204,10 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
         int ret;
 
         btree = (struct nilfs_btree *)bmap;
-        path = nilfs_btree_alloc_path(btree);
+        path = nilfs_btree_alloc_path();
         if (path == NULL)
                 return -ENOMEM;
-        nilfs_btree_init_path(btree, path);
+        nilfs_btree_init_path(path);
 
         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1);
         if (ret < 0) {
@@ -2262,8 +2227,8 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
                 nilfs_bmap_set_dirty(&btree->bt_bmap);
 
  out:
-        nilfs_btree_clear_path(btree, path);
-        nilfs_btree_free_path(btree, path);
+        nilfs_btree_release_path(path);
+        nilfs_btree_free_path(path);
         return ret;
 }