tunnels: fix netns vs proto registration ordering
[safe/jmp/linux-2.6] / fs / nilfs2 / btree.c
index f5a0ec6..7cdd98b 100644 (file)
@@ -29,6 +29,7 @@
 #include "btnode.h"
 #include "btree.h"
 #include "alloc.h"
+#include "dat.h"
 
 /**
  * struct nilfs_btree_path - A path on which B-tree operations are executed
@@ -70,21 +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;
 
@@ -100,26 +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);
 }
 
 /*
@@ -130,7 +114,18 @@ static int nilfs_btree_get_block(const struct nilfs_btree *btree, __u64 ptr,
 {
        struct address_space *btnc =
                &NILFS_BMAP_I((struct nilfs_bmap *)btree)->i_btnode_cache;
-       return nilfs_btnode_get(btnc, ptr, 0, bhp, 0);
+       int err;
+
+       err = nilfs_btnode_submit_block(btnc, ptr, 0, bhp);
+       if (err)
+               return err == -EEXIST ? 0 : err;
+
+       wait_on_buffer(*bhp);
+       if (!buffer_uptodate(*bhp)) {
+               brelse(*bhp);
+               return -EIO;
+       }
+       return 0;
 }
 
 static int nilfs_btree_get_new_block(const struct nilfs_btree *btree,
@@ -138,138 +133,122 @@ static int nilfs_btree_get_new_block(const struct nilfs_btree *btree,
 {
        struct address_space *btnc =
                &NILFS_BMAP_I((struct nilfs_bmap *)btree)->i_btnode_cache;
-       int ret;
+       struct buffer_head *bh;
 
-       ret = nilfs_btnode_get(btnc, ptr, 0, bhp, 1);
-       if (!ret)
-               set_buffer_nilfs_volatile(*bhp);
-       return ret;
+       bh = nilfs_btnode_create_block(btnc, ptr);
+       if (!bh)
+               return -ENOMEM;
+
+       set_buffer_nilfs_volatile(bh);
+       *bhp = bh;
+       return 0;
 }
 
 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);
 }
 
@@ -282,12 +261,12 @@ 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]);
@@ -304,13 +283,13 @@ 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));
@@ -319,8 +298,8 @@ 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. */
@@ -333,13 +312,13 @@ 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));
@@ -348,8 +327,8 @@ 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. */
@@ -361,9 +340,9 @@ 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));
@@ -373,7 +352,7 @@ 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. */
@@ -387,11 +366,11 @@ 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)
@@ -404,11 +383,10 @@ 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;
@@ -416,12 +394,12 @@ 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;
@@ -435,9 +413,8 @@ 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++;
@@ -455,25 +432,20 @@ 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 *
@@ -483,7 +455,19 @@ 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 inline int
+nilfs_btree_bad_node(struct nilfs_btree_node *node, int level)
+{
+       if (unlikely(nilfs_btree_node_get_level(node) != level)) {
+               dump_stack();
+               printk(KERN_CRIT "NILFS: btree level mismatch: %d != %d\n",
+                      nilfs_btree_node_get_level(node), level);
+               return 1;
+       }
+       return 0;
 }
 
 static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
@@ -495,12 +479,11 @@ 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;
@@ -509,14 +492,14 @@ 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);
+               if (nilfs_btree_bad_node(node, level))
+                       return -EINVAL;
                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);
@@ -543,10 +526,10 @@ 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;
@@ -555,15 +538,16 @@ 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);
+               if (nilfs_btree_bad_node(node, level))
+                       return -EINVAL;
+               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;
 
@@ -579,45 +563,121 @@ 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;
 }
 
+static int nilfs_btree_lookup_contig(const struct nilfs_bmap *bmap,
+                                    __u64 key, __u64 *ptrp, unsigned maxblocks)
+{
+       struct nilfs_btree *btree = (struct nilfs_btree *)bmap;
+       struct nilfs_btree_path *path;
+       struct nilfs_btree_node *node;
+       struct inode *dat = NULL;
+       __u64 ptr, ptr2;
+       sector_t blocknr;
+       int level = NILFS_BTREE_LEVEL_NODE_MIN;
+       int ret, cnt, index, maxlevel;
+
+       path = nilfs_btree_alloc_path();
+       if (path == NULL)
+               return -ENOMEM;
+       nilfs_btree_init_path(path);
+       ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);
+       if (ret < 0)
+               goto out;
+
+       if (NILFS_BMAP_USE_VBN(bmap)) {
+               dat = nilfs_bmap_get_dat(bmap);
+               ret = nilfs_dat_translate(dat, ptr, &blocknr);
+               if (ret < 0)
+                       goto out;
+               ptr = blocknr;
+       }
+       cnt = 1;
+       if (cnt == maxblocks)
+               goto end;
+
+       maxlevel = nilfs_btree_height(btree) - 1;
+       node = nilfs_btree_get_node(btree, path, level);
+       index = path[level].bp_index + 1;
+       for (;;) {
+               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);
+                       if (dat) {
+                               ret = nilfs_dat_translate(dat, ptr2, &blocknr);
+                               if (ret < 0)
+                                       goto out;
+                               ptr2 = blocknr;
+                       }
+                       if (ptr2 != ptr + cnt || ++cnt == maxblocks)
+                               goto end;
+                       index++;
+                       continue;
+               }
+               if (level == maxlevel)
+                       break;
+
+               /* 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(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;
+
+               brelse(path[level].bp_bh);
+               path[level].bp_bh = NULL;
+               ret = nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh);
+               if (ret < 0)
+                       goto out;
+               node = nilfs_btree_get_nonroot_node(path, level);
+               index = 0;
+               path[level].bp_index = index;
+       }
+ end:
+       *ptrp = ptr;
+       ret = cnt;
+ out:
+       nilfs_btree_release_path(path);
+       nilfs_btree_free_path(path);
+       return ret;
+}
+
 static void nilfs_btree_promote_key(struct nilfs_btree *btree,
                                    struct nilfs_btree_path *path,
                                    int level, __u64 key)
 {
        if (level < nilfs_btree_height(btree) - 1) {
                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);
-                       unlock_buffer(path[level].bp_bh);
                } while ((path[level].bp_index == 0) &&
                         (++level < nilfs_btree_height(btree) - 1));
        }
 
        /* 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);
        }
 }
@@ -629,18 +689,16 @@ static void nilfs_btree_do_insert(struct nilfs_btree *btree,
        struct nilfs_btree_node *node;
 
        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))
                        nilfs_btnode_mark_dirty(path[level].bp_bh);
-               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_insert(btree, node, *keyp, *ptrp,
@@ -655,13 +713,10 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
        struct nilfs_btree_node *node, *left;
        int nchildren, lnchildren, n, move;
 
-       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;
@@ -678,11 +733,8 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       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);
@@ -706,13 +758,10 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
        struct nilfs_btree_node *node, *right;
        int nchildren, rnchildren, n, move;
 
-       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;
@@ -729,20 +778,16 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       unlock_buffer(path[level].bp_sib_bh);
-
        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);
@@ -761,12 +806,9 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
        __u64 newptr;
        int nchildren, n, move;
 
-       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;
@@ -782,19 +824,15 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       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);
@@ -803,7 +841,7 @@ 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);
@@ -820,27 +858,23 @@ static void nilfs_btree_grow(struct nilfs_btree *btree,
        struct nilfs_btree_node *root, *child;
        int n;
 
-       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);
 
-       unlock_buffer(path[level].bp_sib_bh);
-
        path[level].bp_bh = path[level].bp_sib_bh;
        path[level].bp_sib_bh = NULL;
 
        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;
 }
 
@@ -908,26 +942,29 @@ 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 (btree->bt_ops->btop_find_target != NULL)
+       if (NILFS_BMAP_USE_VBN(&btree->bt_bmap)) {
                path[level].bp_newreq.bpr_ptr =
-                       btree->bt_ops->btop_find_target(btree, path, key);
+                       nilfs_btree_find_target_v(btree, path, key);
+               dat = nilfs_bmap_get_dat(&btree->bt_bmap);
+       }
 
-       ret = btree->bt_bmap.b_pops->bpop_prepare_alloc_ptr(
-               &btree->bt_bmap, &path[level].bp_newreq);
+       ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
+                                          &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;
@@ -944,8 +981,8 @@ 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++;
@@ -956,15 +993,15 @@ 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++;
@@ -976,8 +1013,8 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
                /* split */
                path[level].bp_newreq.bpr_ptr =
                        path[level - 1].bp_newreq.bpr_ptr + 1;
-               ret = btree->bt_bmap.b_pops->bpop_prepare_alloc_ptr(
-                       &btree->bt_bmap, &path[level].bp_newreq);
+               ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
+                                                  &path[level].bp_newreq, dat);
                if (ret < 0)
                        goto err_out_child_node;
                ret = nilfs_btree_get_new_block(btree,
@@ -988,19 +1025,17 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 
                stats->bs_nblocks++;
 
-               lock_buffer(bh);
                nilfs_btree_node_init(btree,
                                      (struct nilfs_btree_node *)bh->b_data,
                                      0, level, 0, NULL, NULL);
-               unlock_buffer(bh);
                path[level].bp_sib_bh = bh;
                path[level].bp_op = nilfs_btree_split;
        }
 
        /* 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;
@@ -1008,8 +1043,8 @@ 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 = btree->bt_bmap.b_pops->bpop_prepare_alloc_ptr(
-               &btree->bt_bmap, &path[level].bp_newreq);
+       ret = nilfs_bmap_prepare_alloc_ptr(&btree->bt_bmap,
+                                          &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,
@@ -1017,10 +1052,8 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
        if (ret < 0)
                goto err_out_curr_node;
 
-       lock_buffer(bh);
        nilfs_btree_node_init(btree, (struct nilfs_btree_node *)bh->b_data,
                              0, level, 0, NULL, NULL);
-       unlock_buffer(bh);
        path[level].bp_sib_bh = bh;
        path[level].bp_op = nilfs_btree_grow;
 
@@ -1037,18 +1070,18 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 
        /* error */
  err_out_curr_node:
-       btree->bt_bmap.b_pops->bpop_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);
-               btree->bt_bmap.b_pops->bpop_abort_alloc_ptr(
-                       &btree->bt_bmap, &path[level].bp_newreq);
+               nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap,
+                                          &path[level].bp_newreq, dat);
 
        }
 
-       btree->bt_bmap.b_pops->bpop_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;
@@ -1059,16 +1092,19 @@ 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 (btree->bt_ops->btop_set_target != NULL)
-               btree->bt_ops->btop_set_target(btree, key, ptr);
+       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++) {
-               btree->bt_bmap.b_pops->bpop_commit_alloc_ptr(
-                       &btree->bt_bmap, &path[level - 1].bp_newreq);
+               nilfs_bmap_commit_alloc_ptr(&btree->bt_bmap,
+                                           &path[level - 1].bp_newreq, dat);
                path[level].bp_op(btree, path, level, &key, &ptr);
        }
 
@@ -1084,10 +1120,10 @@ 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);
@@ -1104,8 +1140,8 @@ 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;
 }
 
@@ -1116,16 +1152,14 @@ static void nilfs_btree_do_delete(struct nilfs_btree *btree,
        struct nilfs_btree_node *node;
 
        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))
                        nilfs_btnode_mark_dirty(path[level].bp_bh);
-               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,
@@ -1142,13 +1176,10 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
 
        nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
 
-       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;
 
@@ -1159,11 +1190,8 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       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;
@@ -1179,13 +1207,10 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
 
        nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
 
-       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;
 
@@ -1196,12 +1221,9 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       unlock_buffer(path[level].bp_sib_bh);
-
        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);
@@ -1217,26 +1239,20 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,
 
        nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
 
-       lock_buffer(path[level].bp_bh);
-       lock_buffer(path[level].bp_sib_bh);
+       node = nilfs_btree_get_nonroot_node(path, level);
+       left = nilfs_btree_get_sib_node(path, level);
 
-       node = nilfs_btree_get_nonroot_node(btree, path, level);
-       left = nilfs_btree_get_sib_node(btree, 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);
 
        if (!buffer_dirty(path[level].bp_sib_bh))
                nilfs_btnode_mark_dirty(path[level].bp_sib_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       unlock_buffer(path[level].bp_sib_bh);
-
        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,
@@ -1248,22 +1264,16 @@ static void nilfs_btree_concat_right(struct nilfs_btree *btree,
 
        nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
 
-       lock_buffer(path[level].bp_bh);
-       lock_buffer(path[level].bp_sib_bh);
+       node = nilfs_btree_get_nonroot_node(path, level);
+       right = nilfs_btree_get_sib_node(path, level);
 
-       node = nilfs_btree_get_nonroot_node(btree, path, level);
-       right = nilfs_btree_get_sib_node(btree, 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);
 
        if (!buffer_dirty(path[level].bp_bh))
                nilfs_btnode_mark_dirty(path[level].bp_bh);
 
-       unlock_buffer(path[level].bp_bh);
-       unlock_buffer(path[level].bp_sib_bh);
-
        nilfs_btnode_delete(path[level].bp_sib_bh);
        path[level].bp_sib_bh = NULL;
        path[level + 1].bp_index++;
@@ -1278,15 +1288,13 @@ static void nilfs_btree_shrink(struct nilfs_btree *btree,
 
        nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
 
-       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);
 
        nilfs_btnode_delete(path[level].bp_bh);
        path[level].bp_bh = NULL;
@@ -1296,7 +1304,8 @@ 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;
@@ -1308,19 +1317,17 @@ 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);
-               if (btree->bt_bmap.b_pops->bpop_prepare_end_ptr != NULL) {
-                       ret = btree->bt_bmap.b_pops->bpop_prepare_end_ptr(
-                               &btree->bt_bmap, &path[level].bp_oldreq);
-                       if (ret < 0)
-                               goto err_out_child_node;
-               }
+               ret = nilfs_bmap_prepare_end_ptr(&btree->bt_bmap,
+                                                &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;
@@ -1337,8 +1344,8 @@ 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++;
@@ -1350,7 +1357,7 @@ 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);
@@ -1358,8 +1365,8 @@ 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++;
@@ -1374,7 +1381,7 @@ 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;
@@ -1391,12 +1398,12 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
        node = nilfs_btree_get_root(btree);
        path[level].bp_oldreq.bpr_ptr =
                nilfs_btree_node_get_ptr(btree, node, path[level].bp_index);
-       if (btree->bt_bmap.b_pops->bpop_prepare_end_ptr != NULL) {
-               ret = btree->bt_bmap.b_pops->bpop_prepare_end_ptr(
-                       &btree->bt_bmap, &path[level].bp_oldreq);
-               if (ret < 0)
-                       goto err_out_child_node;
-       }
+
+       ret = nilfs_bmap_prepare_end_ptr(&btree->bt_bmap,
+                                        &path[level].bp_oldreq, dat);
+       if (ret < 0)
+               goto err_out_child_node;
+
        /* child of the root node is deleted */
        path[level].bp_op = nilfs_btree_do_delete;
        stats->bs_nblocks++;
@@ -1408,15 +1415,12 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 
        /* error */
  err_out_curr_node:
-       if (btree->bt_bmap.b_pops->bpop_abort_end_ptr != NULL)
-               btree->bt_bmap.b_pops->bpop_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);
-               if (btree->bt_bmap.b_pops->bpop_abort_end_ptr != NULL)
-                       btree->bt_bmap.b_pops->bpop_abort_end_ptr(
-                               &btree->bt_bmap, &path[level].bp_oldreq);
+               nilfs_bmap_abort_end_ptr(&btree->bt_bmap,
+                                        &path[level].bp_oldreq, dat);
        }
        *levelp = level;
        stats->bs_nblocks = 0;
@@ -1425,14 +1429,13 @@ 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++) {
-               if (btree->bt_bmap.b_pops->bpop_commit_end_ptr != NULL)
-                       btree->bt_bmap.b_pops->bpop_commit_end_ptr(
-                               &btree->bt_bmap, &path[level].bp_oldreq);
+               nilfs_bmap_commit_end_ptr(&btree->bt_bmap,
+                                         &path[level].bp_oldreq, dat);
                path[level].bp_op(btree, path, level, NULL, NULL);
        }
 
@@ -1446,27 +1449,32 @@ 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;
 }
 
@@ -1477,15 +1485,15 @@ 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;
 }
@@ -1507,7 +1515,7 @@ 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);
@@ -1520,10 +1528,10 @@ 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);
 
@@ -1549,7 +1557,7 @@ 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);
@@ -1562,11 +1570,11 @@ 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]);
@@ -1586,18 +1594,20 @@ 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 (btree->bt_ops->btop_find_target != NULL)
-               dreq->bpr_ptr
-                       = btree->bt_ops->btop_find_target(btree, NULL, key);
-       ret = bmap->b_pops->bpop_prepare_alloc_ptr(bmap, dreq);
+       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, dat);
        if (ret < 0)
                return ret;
 
@@ -1605,7 +1615,7 @@ 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 = bmap->b_pops->bpop_prepare_alloc_ptr(bmap, nreq);
+               ret = nilfs_bmap_prepare_alloc_ptr(bmap, nreq, dat);
                if (ret < 0)
                        goto err_out_dreq;
 
@@ -1622,9 +1632,9 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *bmap, __u64 key,
 
        /* error */
  err_out_nreq:
-       bmap->b_pops->bpop_abort_alloc_ptr(bmap, nreq);
+       nilfs_bmap_abort_alloc_ptr(bmap, nreq, dat);
  err_out_dreq:
-       bmap->b_pops->bpop_abort_alloc_ptr(bmap, dreq);
+       nilfs_bmap_abort_alloc_ptr(bmap, dreq, dat);
        stats->bs_nblocks = 0;
        return ret;
 
@@ -1639,8 +1649,9 @@ 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 */
@@ -1651,14 +1662,13 @@ 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) {
-               bmap->b_pops->bpop_commit_alloc_ptr(bmap, dreq);
-               bmap->b_pops->bpop_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);
                node = (struct nilfs_btree_node *)bh->b_data;
                nilfs_btree_node_init(btree, node, 0, 1, n, keys, ptrs);
                nilfs_btree_node_insert(btree, node,
@@ -1668,7 +1678,6 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
                if (!nilfs_bmap_dirty(bmap))
                        nilfs_bmap_set_dirty(bmap);
 
-               unlock_buffer(bh);
                brelse(bh);
 
                /* create root node at level 2 */
@@ -1677,7 +1686,7 @@ 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 {
-               bmap->b_pops->bpop_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);
@@ -1689,8 +1698,8 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
                        nilfs_bmap_set_dirty(bmap);
        }
 
-       if (btree->bt_ops->btop_set_target != NULL)
-               btree->bt_ops->btop_set_target(btree, key, dreq->bpr_ptr);
+       if (NILFS_BMAP_USE_VBN(bmap))
+               nilfs_btree_set_target_v(btree, key, dreq->bpr_ptr);
 }
 
 /**
@@ -1748,7 +1757,7 @@ 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;
@@ -1758,9 +1767,8 @@ 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(&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;
 
@@ -1772,9 +1780,9 @@ 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(&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;
                }
        }
@@ -1784,13 +1792,13 @@ 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(&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(
@@ -1807,11 +1815,10 @@ 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(&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,
@@ -1820,14 +1827,14 @@ 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;
        }
@@ -1835,7 +1842,7 @@ 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;
        }
@@ -1847,39 +1854,40 @@ 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;
 
@@ -1887,12 +1895,12 @@ 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);
@@ -1912,15 +1920,15 @@ 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;
@@ -1934,11 +1942,13 @@ static int nilfs_btree_propagate(const struct nilfs_bmap *bmap,
                goto out;
        }
 
-       ret = btree->bt_ops->btop_propagate(btree, path, level, bh);
+       ret = NILFS_BMAP_USE_VBN(bmap) ?
+               nilfs_btree_propagate_v(btree, path, level, bh) :
+               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;
 }
@@ -1946,7 +1956,7 @@ 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,
@@ -1961,12 +1971,12 @@ 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;
        }
@@ -2008,7 +2018,7 @@ static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *bmap,
        for (level = NILFS_BTREE_LEVEL_NODE_MIN;
             level < NILFS_BTREE_LEVEL_MAX;
             level++)
-               list_splice(&lists[level], listp->prev);
+               list_splice_tail(&lists[level], listp);
 }
 
 static int nilfs_btree_assign_p(struct nilfs_btree *btree,
@@ -2044,8 +2054,7 @@ 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;
@@ -2061,6 +2070,7 @@ 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;
@@ -2070,12 +2080,12 @@ 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);
@@ -2095,15 +2105,15 @@ 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;
@@ -2115,12 +2125,13 @@ static int nilfs_btree_assign(struct nilfs_bmap *bmap,
                goto out;
        }
 
-       ret = btree->bt_ops->btop_assign(btree, path, level, bh,
-                                           blocknr, binfo);
+       ret = NILFS_BMAP_USE_VBN(bmap) ?
+               nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
+               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;
 }
@@ -2130,19 +2141,18 @@ 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);
 
@@ -2162,10 +2172,10 @@ 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) {
@@ -2185,13 +2195,14 @@ 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;
 }
 
 static const struct nilfs_bmap_operations nilfs_btree_ops = {
        .bop_lookup             =       nilfs_btree_lookup,
+       .bop_lookup_contig      =       nilfs_btree_lookup_contig,
        .bop_insert             =       nilfs_btree_insert,
        .bop_delete             =       nilfs_btree_delete,
        .bop_clear              =       NULL,
@@ -2211,6 +2222,7 @@ static const struct nilfs_bmap_operations nilfs_btree_ops = {
 
 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
        .bop_lookup             =       NULL,
+       .bop_lookup_contig      =       NULL,
        .bop_insert             =       NULL,
        .bop_delete             =       NULL,
        .bop_clear              =       NULL,
@@ -2228,34 +2240,9 @@ static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
        .bop_gather_data        =       NULL,
 };
 
-static const struct nilfs_btree_operations nilfs_btree_ops_v = {
-       .btop_find_target       =       nilfs_btree_find_target_v,
-       .btop_set_target        =       nilfs_btree_set_target_v,
-       .btop_propagate         =       nilfs_btree_propagate_v,
-       .btop_assign            =       nilfs_btree_assign_v,
-};
-
-static const struct nilfs_btree_operations nilfs_btree_ops_p = {
-       .btop_find_target       =       NULL,
-       .btop_set_target        =       NULL,
-       .btop_propagate         =       nilfs_btree_propagate_p,
-       .btop_assign            =       nilfs_btree_assign_p,
-};
-
 int nilfs_btree_init(struct nilfs_bmap *bmap)
 {
-       struct nilfs_btree *btree = (struct nilfs_btree *)bmap;
-
        bmap->b_ops = &nilfs_btree_ops;
-       switch (bmap->b_inode->i_ino) {
-       case NILFS_DAT_INO:
-               btree->bt_ops = &nilfs_btree_ops_p;
-               break;
-       default:
-               btree->bt_ops = &nilfs_btree_ops_v;
-               break;
-       }
-
        return 0;
 }