Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2: (22 commits)
  nilfs2: support contiguous lookup of blocks
  nilfs2: add sync_page method to page caches of meta data
  nilfs2: use device's backing_dev_info for btree node caches
  nilfs2: return EBUSY against delete request on snapshot
  nilfs2: modify list of unsupported features in caveats
  nilfs2: enable sync_page method
  nilfs2: set bio unplug flag for the last bio in segment
  nilfs2: allow future expansion of metadata read out via get info ioctl
  NILFS2: Pagecache usage optimization on NILFS2
  nilfs2: remove nilfs_btree_operations from btree mapping
  nilfs2: remove nilfs_direct_operations from direct mapping
  nilfs2: remove bmap pointer operations
  nilfs2: remove useless b_low and b_high fields from nilfs_bmap struct
  nilfs2: remove pointless NULL check of bpop_commit_alloc_ptr function
  nilfs2: move get block functions in bmap.c into btree codes
  nilfs2: remove nilfs_bmap_delete_block
  nilfs2: remove nilfs_bmap_put_block
  nilfs2: remove header file for segment list operations
  nilfs2: eliminate removal list of segments
  nilfs2: add sufile function that can modify multiple segment usages
  ...

27 files changed, 727 insertions, 861 deletions

diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index 55c4300..01539f4 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -39,9 +39,8 @@ Features which NILFS2 does not support yet:
 	- extended attributes
 	- POSIX ACLs
 	- quotas
-	- writable snapshots
-	- remote backup (CDP)
-	- data integrity
+	- fsck
+	- resize
 	- defragmentation
 
 Mount options
diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
index 064279e..36df60b 100644
--- a/fs/nilfs2/bmap.c
+++ b/fs/nilfs2/bmap.c
@@ -31,21 +31,26 @@
 #include "dat.h"
 #include "alloc.h"
 
+struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)
+{
+	return nilfs_dat_inode(NILFS_I_NILFS(bmap->b_inode));
+}
+
 int nilfs_bmap_lookup_at_level(struct nilfs_bmap *bmap, __u64 key, int level,
 			       __u64 *ptrp)
 {
-	__u64 ptr;
+	sector_t blocknr;
 	int ret;
 
 	down_read(&bmap->b_sem);
 	ret = bmap->b_ops->bop_lookup(bmap, key, level, ptrp);
 	if (ret < 0)
 		goto out;
-	if (bmap->b_pops->bpop_translate != NULL) {
-		ret = bmap->b_pops->bpop_translate(bmap, *ptrp, &ptr);
-		if (ret < 0)
-			goto out;
-		*ptrp = ptr;
+	if (NILFS_BMAP_USE_VBN(bmap)) {
+		ret = nilfs_dat_translate(nilfs_bmap_get_dat(bmap), *ptrp,
+					  &blocknr);
+		if (!ret)
+			*ptrp = blocknr;
 	}
 
  out:
@@ -53,6 +58,16 @@ int nilfs_bmap_lookup_at_level(struct nilfs_bmap *bmap, __u64 key, int level,
 	return ret;
 }
 
+int nilfs_bmap_lookup_contig(struct nilfs_bmap *bmap, __u64 key, __u64 *ptrp,
+			     unsigned maxblocks)
+{
+	int ret;
+
+	down_read(&bmap->b_sem);
+	ret = bmap->b_ops->bop_lookup_contig(bmap, key, ptrp, maxblocks);
+	up_read(&bmap->b_sem);
+	return ret;
+}
 
 /**
  * nilfs_bmap_lookup - find a record
@@ -101,8 +116,7 @@ static int nilfs_bmap_do_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
 			if (n < 0)
 				return n;
 			ret = nilfs_btree_convert_and_insert(
-				bmap, key, ptr, keys, ptrs, n,
-				NILFS_BMAP_LARGE_LOW, NILFS_BMAP_LARGE_HIGH);
+				bmap, key, ptr, keys, ptrs, n);
 			if (ret == 0)
 				bmap->b_u.u_flags |= NILFS_BMAP_LARGE;
 
@@ -158,8 +172,7 @@ static int nilfs_bmap_do_delete(struct nilfs_bmap *bmap, __u64 key)
 			if (n < 0)
 				return n;
 			ret = nilfs_direct_delete_and_convert(
-				bmap, key, keys, ptrs, n,
-				NILFS_BMAP_SMALL_LOW, NILFS_BMAP_SMALL_HIGH);
+				bmap, key, keys, ptrs, n);
 			if (ret == 0)
 				bmap->b_u.u_flags &= ~NILFS_BMAP_LARGE;
 
@@ -417,38 +430,6 @@ void nilfs_bmap_sub_blocks(const struct nilfs_bmap *bmap, int n)
 		mark_inode_dirty(bmap->b_inode);
 }
 
-int nilfs_bmap_get_block(const struct nilfs_bmap *bmap, __u64 ptr,
-			 struct buffer_head **bhp)
-{
-	return nilfs_btnode_get(&NILFS_BMAP_I(bmap)->i_btnode_cache,
-				ptr, 0, bhp, 0);
-}
-
-void nilfs_bmap_put_block(const struct nilfs_bmap *bmap,
-			  struct buffer_head *bh)
-{
-	brelse(bh);
-}
-
-int nilfs_bmap_get_new_block(const struct nilfs_bmap *bmap, __u64 ptr,
-			     struct buffer_head **bhp)
-{
-	int ret;
-
-	ret = nilfs_btnode_get(&NILFS_BMAP_I(bmap)->i_btnode_cache,
-			       ptr, 0, bhp, 1);
-	if (ret < 0)
-		return ret;
-	set_buffer_nilfs_volatile(*bhp);
-	return 0;
-}
-
-void nilfs_bmap_delete_block(const struct nilfs_bmap *bmap,
-			     struct buffer_head *bh)
-{
-	nilfs_btnode_delete(bh);
-}
-
 __u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *bmap,
 			      const struct buffer_head *bh)
 {
@@ -476,11 +457,6 @@ __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *bmap, __u64 key)
 		return NILFS_BMAP_INVALID_PTR;
 }
 
-static struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)
-{
-	return nilfs_dat_inode(NILFS_I_NILFS(bmap->b_inode));
-}
-
 #define NILFS_BMAP_GROUP_DIV	8
 __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *bmap)
 {
@@ -493,64 +469,51 @@ __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *bmap)
 		(entries_per_group / NILFS_BMAP_GROUP_DIV);
 }
 
-static int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req)
+int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *bmap,
+				 union nilfs_bmap_ptr_req *req)
 {
 	return nilfs_dat_prepare_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
 }
 
-static void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req)
+void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *bmap,
+				 union nilfs_bmap_ptr_req *req)
 {
 	nilfs_dat_commit_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
 }
 
-static void nilfs_bmap_abort_alloc_v(struct nilfs_bmap *bmap,
-				     union nilfs_bmap_ptr_req *req)
+void nilfs_bmap_abort_alloc_v(struct nilfs_bmap *bmap,
+			      union nilfs_bmap_ptr_req *req)
 {
 	nilfs_dat_abort_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
 }
 
-static int nilfs_bmap_prepare_start_v(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req)
+int nilfs_bmap_start_v(struct nilfs_bmap *bmap, union nilfs_bmap_ptr_req *req,
+		       sector_t blocknr)
 {
-	return nilfs_dat_prepare_start(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-static void nilfs_bmap_commit_start_v(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req,
-				      sector_t blocknr)
-{
-	nilfs_dat_commit_start(nilfs_bmap_get_dat(bmap), &req->bpr_req,
-			       blocknr);
-}
+	struct inode *dat = nilfs_bmap_get_dat(bmap);
+	int ret;
 
-static void nilfs_bmap_abort_start_v(struct nilfs_bmap *bmap,
-				     union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_abort_start(nilfs_bmap_get_dat(bmap), &req->bpr_req);
+	ret = nilfs_dat_prepare_start(dat, &req->bpr_req);
+	if (likely(!ret))
+		nilfs_dat_commit_start(dat, &req->bpr_req, blocknr);
+	return ret;
 }
 
-static int nilfs_bmap_prepare_end_v(struct nilfs_bmap *bmap,
-				    union nilfs_bmap_ptr_req *req)
+int nilfs_bmap_prepare_end_v(struct nilfs_bmap *bmap,
+			     union nilfs_bmap_ptr_req *req)
 {
 	return nilfs_dat_prepare_end(nilfs_bmap_get_dat(bmap), &req->bpr_req);
 }
 
-static void nilfs_bmap_commit_end_v(struct nilfs_bmap *bmap,
-				    union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_commit_end(nilfs_bmap_get_dat(bmap), &req->bpr_req, 0);
-}
-
-static void nilfs_bmap_commit_end_vmdt(struct nilfs_bmap *bmap,
-				       union nilfs_bmap_ptr_req *req)
+void nilfs_bmap_commit_end_v(struct nilfs_bmap *bmap,
+			     union nilfs_bmap_ptr_req *req)
 {
-	nilfs_dat_commit_end(nilfs_bmap_get_dat(bmap), &req->bpr_req, 1);
+	nilfs_dat_commit_end(nilfs_bmap_get_dat(bmap), &req->bpr_req,
+			     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
 }
 
-static void nilfs_bmap_abort_end_v(struct nilfs_bmap *bmap,
-				   union nilfs_bmap_ptr_req *req)
+void nilfs_bmap_abort_end_v(struct nilfs_bmap *bmap,
+			    union nilfs_bmap_ptr_req *req)
 {
 	nilfs_dat_abort_end(nilfs_bmap_get_dat(bmap), &req->bpr_req);
 }
@@ -566,128 +529,44 @@ int nilfs_bmap_mark_dirty(const struct nilfs_bmap *bmap, __u64 vblocknr)
 	return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(bmap), vblocknr);
 }
 
-int nilfs_bmap_prepare_update(struct nilfs_bmap *bmap,
-			      union nilfs_bmap_ptr_req *oldreq,
-			      union nilfs_bmap_ptr_req *newreq)
+int nilfs_bmap_prepare_update_v(struct nilfs_bmap *bmap,
+				union nilfs_bmap_ptr_req *oldreq,
+				union nilfs_bmap_ptr_req *newreq)
 {
+	struct inode *dat = nilfs_bmap_get_dat(bmap);
 	int ret;
 
-	ret = bmap->b_pops->bpop_prepare_end_ptr(bmap, oldreq);
+	ret = nilfs_dat_prepare_end(dat, &oldreq->bpr_req);
 	if (ret < 0)
 		return ret;
-	ret = bmap->b_pops->bpop_prepare_alloc_ptr(bmap, newreq);
+	ret = nilfs_dat_prepare_alloc(dat, &newreq->bpr_req);
 	if (ret < 0)
-		bmap->b_pops->bpop_abort_end_ptr(bmap, oldreq);
+		nilfs_dat_abort_end(dat, &oldreq->bpr_req);
 
 	return ret;
 }
 
-void nilfs_bmap_commit_update(struct nilfs_bmap *bmap,
-			      union nilfs_bmap_ptr_req *oldreq,
-			      union nilfs_bmap_ptr_req *newreq)
+void nilfs_bmap_commit_update_v(struct nilfs_bmap *bmap,
+				union nilfs_bmap_ptr_req *oldreq,
+				union nilfs_bmap_ptr_req *newreq)
 {
-	bmap->b_pops->bpop_commit_end_ptr(bmap, oldreq);
-	bmap->b_pops->bpop_commit_alloc_ptr(bmap, newreq);
-}
+	struct inode *dat = nilfs_bmap_get_dat(bmap);
 
-void nilfs_bmap_abort_update(struct nilfs_bmap *bmap,
-			     union nilfs_bmap_ptr_req *oldreq,
-			     union nilfs_bmap_ptr_req *newreq)
-{
-	bmap->b_pops->bpop_abort_end_ptr(bmap, oldreq);
-	bmap->b_pops->bpop_abort_alloc_ptr(bmap, newreq);
+	nilfs_dat_commit_end(dat, &oldreq->bpr_req,
+			     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
+	nilfs_dat_commit_alloc(dat, &newreq->bpr_req);
 }
 
-static int nilfs_bmap_translate_v(const struct nilfs_bmap *bmap, __u64 ptr,
-				  __u64 *ptrp)
+void nilfs_bmap_abort_update_v(struct nilfs_bmap *bmap,
+			       union nilfs_bmap_ptr_req *oldreq,
+			       union nilfs_bmap_ptr_req *newreq)
 {
-	sector_t blocknr;
-	int ret;
-
-	ret = nilfs_dat_translate(nilfs_bmap_get_dat(bmap), ptr, &blocknr);
-	if (ret < 0)
-		return ret;
-	if (ptrp != NULL)
-		*ptrp = blocknr;
-	return 0;
-}
+	struct inode *dat = nilfs_bmap_get_dat(bmap);
 
-static int nilfs_bmap_prepare_alloc_p(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req)
-{
-	/* ignore target ptr */
-	req->bpr_ptr = bmap->b_last_allocated_ptr++;
-	return 0;
+	nilfs_dat_abort_end(dat, &oldreq->bpr_req);
+	nilfs_dat_abort_alloc(dat, &newreq->bpr_req);
 }
 
-static void nilfs_bmap_commit_alloc_p(struct nilfs_bmap *bmap,
-				      union nilfs_bmap_ptr_req *req)
-{
-	/* do nothing */
-}
-
-static void nilfs_bmap_abort_alloc_p(struct nilfs_bmap *bmap,
-				     union nilfs_bmap_ptr_req *req)
-{
-	bmap->b_last_allocated_ptr--;
-}
-
-static const struct nilfs_bmap_ptr_operations nilfs_bmap_ptr_ops_v = {
-	.bpop_prepare_alloc_ptr	=	nilfs_bmap_prepare_alloc_v,
-	.bpop_commit_alloc_ptr	=	nilfs_bmap_commit_alloc_v,
-	.bpop_abort_alloc_ptr	=	nilfs_bmap_abort_alloc_v,
-	.bpop_prepare_start_ptr	=	nilfs_bmap_prepare_start_v,
-	.bpop_commit_start_ptr	=	nilfs_bmap_commit_start_v,
-	.bpop_abort_start_ptr	=	nilfs_bmap_abort_start_v,
-	.bpop_prepare_end_ptr	=	nilfs_bmap_prepare_end_v,
-	.bpop_commit_end_ptr	=	nilfs_bmap_commit_end_v,
-	.bpop_abort_end_ptr	=	nilfs_bmap_abort_end_v,
-
-	.bpop_translate		=	nilfs_bmap_translate_v,
-};
-
-static const struct nilfs_bmap_ptr_operations nilfs_bmap_ptr_ops_vmdt = {
-	.bpop_prepare_alloc_ptr	=	nilfs_bmap_prepare_alloc_v,
-	.bpop_commit_alloc_ptr	=	nilfs_bmap_commit_alloc_v,
-	.bpop_abort_alloc_ptr	=	nilfs_bmap_abort_alloc_v,
-	.bpop_prepare_start_ptr	=	nilfs_bmap_prepare_start_v,
-	.bpop_commit_start_ptr	=	nilfs_bmap_commit_start_v,
-	.bpop_abort_start_ptr	=	nilfs_bmap_abort_start_v,
-	.bpop_prepare_end_ptr	=	nilfs_bmap_prepare_end_v,
-	.bpop_commit_end_ptr	=	nilfs_bmap_commit_end_vmdt,
-	.bpop_abort_end_ptr	=	nilfs_bmap_abort_end_v,
-
-	.bpop_translate		=	nilfs_bmap_translate_v,
-};
-
-static const struct nilfs_bmap_ptr_operations nilfs_bmap_ptr_ops_p = {
-	.bpop_prepare_alloc_ptr	=	nilfs_bmap_prepare_alloc_p,
-	.bpop_commit_alloc_ptr	=	nilfs_bmap_commit_alloc_p,
-	.bpop_abort_alloc_ptr	=	nilfs_bmap_abort_alloc_p,
-	.bpop_prepare_start_ptr	=	NULL,
-	.bpop_commit_start_ptr	=	NULL,
-	.bpop_abort_start_ptr	=	NULL,
-	.bpop_prepare_end_ptr	=	NULL,
-	.bpop_commit_end_ptr	=	NULL,
-	.bpop_abort_end_ptr	=	NULL,
-
-	.bpop_translate		=	NULL,
-};
-
-static const struct nilfs_bmap_ptr_operations nilfs_bmap_ptr_ops_gc = {
-	.bpop_prepare_alloc_ptr	=	NULL,
-	.bpop_commit_alloc_ptr	=	NULL,
-	.bpop_abort_alloc_ptr	=	NULL,
-	.bpop_prepare_start_ptr	=	NULL,
-	.bpop_commit_start_ptr	=	NULL,
-	.bpop_abort_start_ptr	=	NULL,
-	.bpop_prepare_end_ptr	=	NULL,
-	.bpop_commit_end_ptr	=	NULL,
-	.bpop_abort_end_ptr	=	NULL,
-
-	.bpop_translate		=	NULL,
-};
-
 static struct lock_class_key nilfs_bmap_dat_lock_key;
 
 /**
@@ -714,31 +593,26 @@ int nilfs_bmap_read(struct nilfs_bmap *bmap, struct nilfs_inode *raw_inode)
 	bmap->b_inode = &NILFS_BMAP_I(bmap)->vfs_inode;
 	switch (bmap->b_inode->i_ino) {
 	case NILFS_DAT_INO:
-		bmap->b_pops = &nilfs_bmap_ptr_ops_p;
-		bmap->b_last_allocated_key = 0;	/* XXX: use macro */
+		bmap->b_ptr_type = NILFS_BMAP_PTR_P;
+		bmap->b_last_allocated_key = 0;
 		bmap->b_last_allocated_ptr = NILFS_BMAP_NEW_PTR_INIT;
 		lockdep_set_class(&bmap->b_sem, &nilfs_bmap_dat_lock_key);
 		break;
 	case NILFS_CPFILE_INO:
 	case NILFS_SUFILE_INO:
-		bmap->b_pops = &nilfs_bmap_ptr_ops_vmdt;
-		bmap->b_last_allocated_key = 0;	/* XXX: use macro */
+		bmap->b_ptr_type = NILFS_BMAP_PTR_VS;
+		bmap->b_last_allocated_key = 0;
 		bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;
 		break;
 	default:
-		bmap->b_pops = &nilfs_bmap_ptr_ops_v;
-		bmap->b_last_allocated_key = 0;	/* XXX: use macro */
+		bmap->b_ptr_type = NILFS_BMAP_PTR_VM;
+		bmap->b_last_allocated_key = 0;
 		bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;
 		break;
 	}
 
 	return (bmap->b_u.u_flags & NILFS_BMAP_LARGE) ?
-		nilfs_btree_init(bmap,
-				 NILFS_BMAP_LARGE_LOW,
-				 NILFS_BMAP_LARGE_HIGH) :
-		nilfs_direct_init(bmap,
-				  NILFS_BMAP_SMALL_LOW,
-				  NILFS_BMAP_SMALL_HIGH);
+		nilfs_btree_init(bmap) : nilfs_direct_init(bmap);
 }
 
 /**
@@ -764,7 +638,7 @@ void nilfs_bmap_init_gc(struct nilfs_bmap *bmap)
 	memset(&bmap->b_u, 0, NILFS_BMAP_SIZE);
 	init_rwsem(&bmap->b_sem);
 	bmap->b_inode = &NILFS_BMAP_I(bmap)->vfs_inode;
-	bmap->b_pops = &nilfs_bmap_ptr_ops_gc;
+	bmap->b_ptr_type = NILFS_BMAP_PTR_U;
 	bmap->b_last_allocated_key = 0;
 	bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;
 	bmap->b_state = 0;
diff --git a/fs/nilfs2/bmap.h b/fs/nilfs2/bmap.h
index 4f2708a..b2890cd 100644
--- a/fs/nilfs2/bmap.h
+++ b/fs/nilfs2/bmap.h
@@ -64,6 +64,8 @@ struct nilfs_bmap_stats {
  */
 struct nilfs_bmap_operations {
 	int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
+	int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,
+				 unsigned);
 	int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
 	int (*bop_delete)(struct nilfs_bmap *, __u64);
 	void (*bop_clear)(struct nilfs_bmap *);
@@ -86,34 +88,6 @@ struct nilfs_bmap_operations {
 };
 
 
-/**
- * struct nilfs_bmap_ptr_operations - bmap ptr operation table
- */
-struct nilfs_bmap_ptr_operations {
-	int (*bpop_prepare_alloc_ptr)(struct nilfs_bmap *,
-				      union nilfs_bmap_ptr_req *);
-	void (*bpop_commit_alloc_ptr)(struct nilfs_bmap *,
-				      union nilfs_bmap_ptr_req *);
-	void (*bpop_abort_alloc_ptr)(struct nilfs_bmap *,
-				     union nilfs_bmap_ptr_req *);
-	int (*bpop_prepare_start_ptr)(struct nilfs_bmap *,
-				      union nilfs_bmap_ptr_req *);
-	void (*bpop_commit_start_ptr)(struct nilfs_bmap *,
-				      union nilfs_bmap_ptr_req *,
-				      sector_t);
-	void (*bpop_abort_start_ptr)(struct nilfs_bmap *,
-				     union nilfs_bmap_ptr_req *);
-	int (*bpop_prepare_end_ptr)(struct nilfs_bmap *,
-				    union nilfs_bmap_ptr_req *);
-	void (*bpop_commit_end_ptr)(struct nilfs_bmap *,
-				    union nilfs_bmap_ptr_req *);
-	void (*bpop_abort_end_ptr)(struct nilfs_bmap *,
-				   union nilfs_bmap_ptr_req *);
-
-	int (*bpop_translate)(const struct nilfs_bmap *, __u64, __u64 *);
-};
-
-
 #define NILFS_BMAP_SIZE		(NILFS_INODE_BMAP_SIZE * sizeof(__le64))
 #define NILFS_BMAP_KEY_BIT	(sizeof(unsigned long) * 8 /* CHAR_BIT */)
 #define NILFS_BMAP_NEW_PTR_INIT	\
@@ -131,11 +105,9 @@ static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
  * @b_sem: semaphore
  * @b_inode: owner of bmap
  * @b_ops: bmap operation table
- * @b_pops: bmap ptr operation table
- * @b_low: low watermark of conversion
- * @b_high: high watermark of conversion
  * @b_last_allocated_key: last allocated key for data block
  * @b_last_allocated_ptr: last allocated ptr for data block
+ * @b_ptr_type: pointer type
  * @b_state: state
  */
 struct nilfs_bmap {
@@ -146,14 +118,22 @@ struct nilfs_bmap {
 	struct rw_semaphore b_sem;
 	struct inode *b_inode;
 	const struct nilfs_bmap_operations *b_ops;
-	const struct nilfs_bmap_ptr_operations *b_pops;
-	__u64 b_low;
-	__u64 b_high;
 	__u64 b_last_allocated_key;
 	__u64 b_last_allocated_ptr;
+	int b_ptr_type;
 	int b_state;
 };
 
+/* pointer type */
+#define NILFS_BMAP_PTR_P	0	/* physical block number (i.e. LBN) */
+#define NILFS_BMAP_PTR_VS	1	/* virtual block number (single
+					   version) */
+#define NILFS_BMAP_PTR_VM	2	/* virtual block number (has multiple
+					   versions) */
+#define NILFS_BMAP_PTR_U	(-1)	/* never perform pointer operations */
+
+#define NILFS_BMAP_USE_VBN(bmap)	((bmap)->b_ptr_type > 0)
+
 /* state */
 #define NILFS_BMAP_DIRTY	0x00000001
 
@@ -162,6 +142,7 @@ int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
 int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
 void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
 int nilfs_bmap_lookup(struct nilfs_bmap *, unsigned long, unsigned long *);
+int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
 int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
 int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
 int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
@@ -182,7 +163,67 @@ void nilfs_bmap_commit_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
 /*
  * Internal use only
  */
+struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);
+int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *,
+			       union nilfs_bmap_ptr_req *);
+void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *,
+			       union nilfs_bmap_ptr_req *);
+void nilfs_bmap_abort_alloc_v(struct nilfs_bmap *,
+			      union nilfs_bmap_ptr_req *);
 
+static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
+					       union nilfs_bmap_ptr_req *req)
+{
+	if (NILFS_BMAP_USE_VBN(bmap))
+		return nilfs_bmap_prepare_alloc_v(bmap, req);
+	/* ignore target ptr */
+	req->bpr_ptr = bmap->b_last_allocated_ptr++;
+	return 0;
+}
+
+static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
+					       union nilfs_bmap_ptr_req *req)
+{
+	if (NILFS_BMAP_USE_VBN(bmap))
+		nilfs_bmap_commit_alloc_v(bmap, req);
+}
+
+static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
+					      union nilfs_bmap_ptr_req *req)
+{
+	if (NILFS_BMAP_USE_VBN(bmap))
+		nilfs_bmap_abort_alloc_v(bmap, req);
+	else
+		bmap->b_last_allocated_ptr--;
+}
+
+int nilfs_bmap_prepare_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
+void nilfs_bmap_commit_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
+void nilfs_bmap_abort_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
+
+static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
+					     union nilfs_bmap_ptr_req *req)
+{
+	return NILFS_BMAP_USE_VBN(bmap) ?
+		nilfs_bmap_prepare_end_v(bmap, req) : 0;
+}
+
+static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
+					     union nilfs_bmap_ptr_req *req)
+{
+	if (NILFS_BMAP_USE_VBN(bmap))
+		nilfs_bmap_commit_end_v(bmap, req);
+}
+
+static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
+					    union nilfs_bmap_ptr_req *req)
+{
+	if (NILFS_BMAP_USE_VBN(bmap))
+		nilfs_bmap_abort_end_v(bmap, req);
+}
+
+int nilfs_bmap_start_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *,
+		       sector_t);
 int nilfs_bmap_move_v(const struct nilfs_bmap *, __u64, sector_t);
 int nilfs_bmap_mark_dirty(const struct nilfs_bmap *, __u64);
 
@@ -193,28 +234,20 @@ __u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
 __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
 __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);
 
-int nilfs_bmap_prepare_update(struct nilfs_bmap *,
-			      union nilfs_bmap_ptr_req *,
-			      union nilfs_bmap_ptr_req *);
-void nilfs_bmap_commit_update(struct nilfs_bmap *,
-			      union nilfs_bmap_ptr_req *,
-			      union nilfs_bmap_ptr_req *);
-void nilfs_bmap_abort_update(struct nilfs_bmap *,
-			     union nilfs_bmap_ptr_req *,
-			     union nilfs_bmap_ptr_req *);
+int nilfs_bmap_prepare_update_v(struct nilfs_bmap *,
+				union nilfs_bmap_ptr_req *,
+				union nilfs_bmap_ptr_req *);
+void nilfs_bmap_commit_update_v(struct nilfs_bmap *,
+				union nilfs_bmap_ptr_req *,
+				union nilfs_bmap_ptr_req *);
+void nilfs_bmap_abort_update_v(struct nilfs_bmap *,
+			       union nilfs_bmap_ptr_req *,
+			       union nilfs_bmap_ptr_req *);
 
 void nilfs_bmap_add_blocks(const struct nilfs_bmap *, int);
 void nilfs_bmap_sub_blocks(const struct nilfs_bmap *, int);
 
 
-int nilfs_bmap_get_block(const struct nilfs_bmap *, __u64,
-			 struct buffer_head **);
-void nilfs_bmap_put_block(const struct nilfs_bmap *, struct buffer_head *);
-int nilfs_bmap_get_new_block(const struct nilfs_bmap *, __u64,
-			     struct buffer_head **);
-void nilfs_bmap_delete_block(const struct nilfs_bmap *, struct buffer_head *);
-
-
 /* Assume that bmap semaphore is locked. */
 static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
 {
diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
index 4cc07b2..7e0b61b 100644
--- a/fs/nilfs2/btnode.c
+++ b/fs/nilfs2/btnode.c
@@ -46,15 +46,18 @@ void nilfs_btnode_cache_init_once(struct address_space *btnc)
 	INIT_LIST_HEAD(&btnc->i_mmap_nonlinear);
 }
 
-static struct address_space_operations def_btnode_aops;
+static struct address_space_operations def_btnode_aops = {
+	.sync_page		= block_sync_page,
+};
 
-void nilfs_btnode_cache_init(struct address_space *btnc)
+void nilfs_btnode_cache_init(struct address_space *btnc,
+			     struct backing_dev_info *bdi)
 {
 	btnc->host = NULL;  /* can safely set to host inode ? */
 	btnc->flags = 0;
 	mapping_set_gfp_mask(btnc, GFP_NOFS);
 	btnc->assoc_mapping = NULL;
-	btnc->backing_dev_info = &default_backing_dev_info;
+	btnc->backing_dev_info = bdi;
 	btnc->a_ops = &def_btnode_aops;
 }
 
diff --git a/fs/nilfs2/btnode.h b/fs/nilfs2/btnode.h
index 35faa86..3e22751 100644
--- a/fs/nilfs2/btnode.h
+++ b/fs/nilfs2/btnode.h
@@ -38,7 +38,7 @@ struct nilfs_btnode_chkey_ctxt {
 };
 
 void nilfs_btnode_cache_init_once(struct address_space *);
-void nilfs_btnode_cache_init(struct address_space *);
+void nilfs_btnode_cache_init(struct address_space *, struct backing_dev_info *);
 void nilfs_btnode_cache_clear(struct address_space *);
 int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t,
 			      struct buffer_head **, int);
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 6b37a27..aa41272 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -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
@@ -109,8 +110,7 @@ static void nilfs_btree_clear_path(const struct nilfs_btree *btree,
 	     level < NILFS_BTREE_LEVEL_MAX;
 	     level++) {
 		if (path[level].bp_bh != NULL) {
-			nilfs_bmap_put_block(&btree->bt_bmap,
-					     path[level].bp_bh);
+			brelse(path[level].bp_bh);
 			path[level].bp_bh = NULL;
 		}
 		/* sib_bh is released or deleted by prepare or commit
@@ -123,10 +123,29 @@ static void nilfs_btree_clear_path(const struct nilfs_btree *btree,
 	}
 }
 
-
 /*
  * B-tree node operations
  */
+static int nilfs_btree_get_block(const struct nilfs_btree *btree, __u64 ptr,
+				 struct buffer_head **bhp)
+{
+	struct address_space *btnc =
+		&NILFS_BMAP_I((struct nilfs_bmap *)btree)->i_btnode_cache;
+	return nilfs_btnode_get(btnc, ptr, 0, bhp, 0);
+}
+
+static int nilfs_btree_get_new_block(const struct nilfs_btree *btree,
+				     __u64 ptr, struct buffer_head **bhp)
+{
+	struct address_space *btnc =
+		&NILFS_BMAP_I((struct nilfs_bmap *)btree)->i_btnode_cache;
+	int ret;
+
+	ret = nilfs_btnode_get(btnc, ptr, 0, bhp, 1);
+	if (!ret)
+		set_buffer_nilfs_volatile(*bhp);
+	return ret;
+}
 
 static inline int
 nilfs_btree_node_get_flags(const struct nilfs_btree *btree,
@@ -488,8 +507,7 @@ static int nilfs_btree_do_lookup(const struct nilfs_btree *btree,
 	path[level].bp_index = index;
 
 	for (level--; level >= minlevel; level--) {
-		ret = nilfs_bmap_get_block(&btree->bt_bmap, ptr,
-					   &path[level].bp_bh);
+		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);
@@ -535,8 +553,7 @@ static int nilfs_btree_do_lookup_last(const struct nilfs_btree *btree,
 	path[level].bp_index = index;
 
 	for (level--; level > 0; level--) {
-		ret = nilfs_bmap_get_block(&btree->bt_bmap, ptr,
-					   &path[level].bp_bh);
+		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);
@@ -579,6 +596,87 @@ static int nilfs_btree_lookup(const struct nilfs_bmap *bmap,
 	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(btree);
+	if (path == NULL)
+		return -ENOMEM;
+	nilfs_btree_init_path(btree, 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(btree, node)) {
+			if (nilfs_btree_node_get_key(btree, 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(btree, node) ||
+		    nilfs_btree_node_get_key(btree, 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(btree, path, level);
+		index = 0;
+		path[level].bp_index = index;
+	}
+ end:
+	*ptrp = ptr;
+	ret = cnt;
+ out:
+	nilfs_btree_clear_path(btree, path);
+	nilfs_btree_free_path(btree, path);
+	return ret;
+}
+
 static void nilfs_btree_promote_key(struct nilfs_btree *btree,
 				    struct nilfs_btree_path *path,
 				    int level, __u64 key)
@@ -669,13 +767,13 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
 				nilfs_btree_node_get_key(btree, node, 0));
 
 	if (move) {
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_bh);
+		brelse(path[level].bp_bh);
 		path[level].bp_bh = path[level].bp_sib_bh;
 		path[level].bp_sib_bh = NULL;
 		path[level].bp_index += lnchildren;
 		path[level + 1].bp_index--;
 	} else {
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_sib_bh);
+		brelse(path[level].bp_sib_bh);
 		path[level].bp_sib_bh = NULL;
 		path[level].bp_index -= n;
 	}
@@ -722,14 +820,14 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
 	path[level + 1].bp_index--;
 
 	if (move) {
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_bh);
+		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 + 1].bp_index++;
 	} else {
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_sib_bh);
+		brelse(path[level].bp_sib_bh);
 		path[level].bp_sib_bh = NULL;
 	}
 
@@ -781,7 +879,7 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
 		*keyp = nilfs_btree_node_get_key(btree, right, 0);
 		*ptrp = path[level].bp_newreq.bpr_ptr;
 
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_bh);
+		brelse(path[level].bp_bh);
 		path[level].bp_bh = path[level].bp_sib_bh;
 		path[level].bp_sib_bh = NULL;
 	} else {
@@ -790,7 +888,7 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
 		*keyp = nilfs_btree_node_get_key(btree, right, 0);
 		*ptrp = path[level].bp_newreq.bpr_ptr;
 
-		nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_sib_bh);
+		brelse(path[level].bp_sib_bh);
 		path[level].bp_sib_bh = NULL;
 	}
 
@@ -897,12 +995,12 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 	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);
 
-	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);
 	if (ret < 0)
 		goto err_out_data;
 
@@ -924,8 +1022,7 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 		if (pindex > 0) {
 			sibptr = nilfs_btree_node_get_ptr(btree, parent,
 							  pindex - 1);
-			ret = nilfs_bmap_get_block(&btree->bt_bmap, sibptr,
-						   &bh);
+			ret = nilfs_btree_get_block(btree, sibptr, &bh);
 			if (ret < 0)
 				goto err_out_child_node;
 			sib = (struct nilfs_btree_node *)bh->b_data;
@@ -936,7 +1033,7 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 				stats->bs_nblocks++;
 				goto out;
 			} else
-				nilfs_bmap_put_block(&btree->bt_bmap, bh);
+				brelse(bh);
 		}
 
 		/* right sibling */
@@ -944,8 +1041,7 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 		    nilfs_btree_node_get_nchildren(btree, parent) - 1) {
 			sibptr = nilfs_btree_node_get_ptr(btree, parent,
 							  pindex + 1);
-			ret = nilfs_bmap_get_block(&btree->bt_bmap, sibptr,
-						   &bh);
+			ret = nilfs_btree_get_block(btree, sibptr, &bh);
 			if (ret < 0)
 				goto err_out_child_node;
 			sib = (struct nilfs_btree_node *)bh->b_data;
@@ -956,19 +1052,19 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
 				stats->bs_nblocks++;
 				goto out;
 			} else
-				nilfs_bmap_put_block(&btree->bt_bmap, bh);
+				brelse(bh);
 		}
 
 		/* 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);
 		if (ret < 0)
 			goto err_out_child_node;
-		ret = nilfs_bmap_get_new_block(&btree->bt_bmap,
-					       path[level].bp_newreq.bpr_ptr,
-					       &bh);
+		ret = nilfs_btree_get_new_block(btree,
+						path[level].bp_newreq.bpr_ptr,
+						&bh);
 		if (ret < 0)
 			goto err_out_curr_node;
 
@@ -994,12 +1090,12 @@ 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);
 	if (ret < 0)
 		goto err_out_child_node;
-	ret = nilfs_bmap_get_new_block(&btree->bt_bmap,
-				       path[level].bp_newreq.bpr_ptr, &bh);
+	ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
+					&bh);
 	if (ret < 0)
 		goto err_out_curr_node;
 
@@ -1023,18 +1119,16 @@ 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);
  err_out_child_node:
 	for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
-		nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_sib_bh);
-		btree->bt_bmap.b_pops->bpop_abort_alloc_ptr(
-			&btree->bt_bmap, &path[level].bp_newreq);
+		nilfs_btnode_delete(path[level].bp_sib_bh);
+		nilfs_bmap_abort_alloc_ptr(&btree->bt_bmap,
+					   &path[level].bp_newreq);
 
 	}
 
-	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);
  err_out_data:
 	*levelp = level;
 	stats->bs_nblocks = 0;
@@ -1049,14 +1143,12 @@ static void nilfs_btree_commit_insert(struct nilfs_btree *btree,
 
 	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);
 
 	for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
-		if (btree->bt_bmap.b_pops->bpop_commit_alloc_ptr != NULL) {
-			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);
 		path[level].bp_op(btree, path, level, &key, &ptr);
 	}
 
@@ -1153,7 +1245,7 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
 	nilfs_btree_promote_key(btree, path, level + 1,
 				nilfs_btree_node_get_key(btree, node, 0));
 
-	nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_sib_bh);
+	brelse(path[level].bp_sib_bh);
 	path[level].bp_sib_bh = NULL;
 	path[level].bp_index += n;
 }
@@ -1192,7 +1284,7 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
 				nilfs_btree_node_get_key(btree, right, 0));
 	path[level + 1].bp_index--;
 
-	nilfs_bmap_put_block(&btree->bt_bmap, path[level].bp_sib_bh);
+	brelse(path[level].bp_sib_bh);
 	path[level].bp_sib_bh = NULL;
 }
 
@@ -1221,7 +1313,7 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,
 	unlock_buffer(path[level].bp_bh);
 	unlock_buffer(path[level].bp_sib_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_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);
@@ -1252,7 +1344,7 @@ static void nilfs_btree_concat_right(struct nilfs_btree *btree,
 	unlock_buffer(path[level].bp_bh);
 	unlock_buffer(path[level].bp_sib_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_sib_bh);
+	nilfs_btnode_delete(path[level].bp_sib_bh);
 	path[level].bp_sib_bh = NULL;
 	path[level + 1].bp_index++;
 }
@@ -1276,7 +1368,7 @@ static void nilfs_btree_shrink(struct nilfs_btree *btree,
 	nilfs_btree_node_move_left(btree, root, child, n);
 	unlock_buffer(path[level].bp_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_bh);
+	nilfs_btnode_delete(path[level].bp_bh);
 	path[level].bp_bh = NULL;
 }
 
@@ -1300,12 +1392,10 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *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);
+		if (ret < 0)
+			goto err_out_child_node;
 
 		if (nilfs_btree_node_get_nchildren(btree, node) >
 		    nilfs_btree_node_nchildren_min(btree, node)) {
@@ -1321,8 +1411,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 			/* left sibling */
 			sibptr = nilfs_btree_node_get_ptr(btree, parent,
 							  pindex - 1);
-			ret = nilfs_bmap_get_block(&btree->bt_bmap, sibptr,
-						   &bh);
+			ret = nilfs_btree_get_block(btree, sibptr, &bh);
 			if (ret < 0)
 				goto err_out_curr_node;
 			sib = (struct nilfs_btree_node *)bh->b_data;
@@ -1343,8 +1432,7 @@ static int nilfs_btree_prepare_delete(struct nilfs_btree *btree,
 			/* right sibling */
 			sibptr = nilfs_btree_node_get_ptr(btree, parent,
 							  pindex + 1);
-			ret = nilfs_bmap_get_block(&btree->bt_bmap, sibptr,
-						   &bh);
+			ret = nilfs_btree_get_block(btree, sibptr, &bh);
 			if (ret < 0)
 				goto err_out_curr_node;
 			sib = (struct nilfs_btree_node *)bh->b_data;
@@ -1381,12 +1469,12 @@ 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);
+	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++;
@@ -1398,15 +1486,12 @@ 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);
  err_out_child_node:
 	for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
-		nilfs_bmap_put_block(&btree->bt_bmap, 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);
+		brelse(path[level].bp_sib_bh);
+		nilfs_bmap_abort_end_ptr(&btree->bt_bmap,
+					 &path[level].bp_oldreq);
 	}
 	*levelp = level;
 	stats->bs_nblocks = 0;
@@ -1420,9 +1505,8 @@ static void nilfs_btree_commit_delete(struct nilfs_btree *btree,
 	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);
 		path[level].bp_op(btree, path, level, NULL, NULL);
 	}
 
@@ -1501,7 +1585,7 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *bmap, __u64 key)
 		if (nchildren > 1)
 			return 0;
 		ptr = nilfs_btree_node_get_ptr(btree, root, nchildren - 1);
-		ret = nilfs_bmap_get_block(bmap, ptr, &bh);
+		ret = nilfs_btree_get_block(btree, ptr, &bh);
 		if (ret < 0)
 			return ret;
 		node = (struct nilfs_btree_node *)bh->b_data;
@@ -1515,9 +1599,9 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *bmap, __u64 key)
 	nextmaxkey = (nchildren > 1) ?
 		nilfs_btree_node_get_key(btree, node, nchildren - 2) : 0;
 	if (bh != NULL)
-		nilfs_bmap_put_block(bmap, bh);
+		brelse(bh);
 
-	return (maxkey == key) && (nextmaxkey < bmap->b_low);
+	return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
 }
 
 static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
@@ -1542,7 +1626,7 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
 		nchildren = nilfs_btree_node_get_nchildren(btree, root);
 		WARN_ON(nchildren > 1);
 		ptr = nilfs_btree_node_get_ptr(btree, root, nchildren - 1);
-		ret = nilfs_bmap_get_block(bmap, ptr, &bh);
+		ret = nilfs_btree_get_block(btree, ptr, &bh);
 		if (ret < 0)
 			return ret;
 		node = (struct nilfs_btree_node *)bh->b_data;
@@ -1563,7 +1647,7 @@ static int nilfs_btree_gather_data(struct nilfs_bmap *bmap,
 	}
 
 	if (bh != NULL)
-		nilfs_bmap_put_block(bmap, bh);
+		brelse(bh);
 
 	return nitems;
 }
@@ -1584,10 +1668,10 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *bmap, __u64 key,
 
 	/* 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);
+
+	ret = nilfs_bmap_prepare_alloc_ptr(bmap, dreq);
 	if (ret < 0)
 		return ret;
 
@@ -1595,11 +1679,11 @@ 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);
 		if (ret < 0)
 			goto err_out_dreq;
 
-		ret = nilfs_bmap_get_new_block(bmap, nreq->bpr_ptr, &bh);
+		ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
 		if (ret < 0)
 			goto err_out_nreq;
 
@@ -1612,9 +1696,9 @@ 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);
  err_out_dreq:
-	bmap->b_pops->bpop_abort_alloc_ptr(bmap, dreq);
+	nilfs_bmap_abort_alloc_ptr(bmap, dreq);
 	stats->bs_nblocks = 0;
 	return ret;
 
@@ -1624,7 +1708,7 @@ static void
 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
 				      __u64 key, __u64 ptr,
 				      const __u64 *keys, const __u64 *ptrs,
-				      int n, __u64 low, __u64 high,
+				      int n,
 				      union nilfs_bmap_ptr_req *dreq,
 				      union nilfs_bmap_ptr_req *nreq,
 				      struct buffer_head *bh)
@@ -1642,12 +1726,10 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
 
 	/* convert and insert */
 	btree = (struct nilfs_btree *)bmap;
-	nilfs_btree_init(bmap, low, high);
+	nilfs_btree_init(bmap);
 	if (nreq != NULL) {
-		if (bmap->b_pops->bpop_commit_alloc_ptr != 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);
+		nilfs_bmap_commit_alloc_ptr(bmap, nreq);
 
 		/* create child node at level 1 */
 		lock_buffer(bh);
@@ -1661,7 +1743,7 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
 			nilfs_bmap_set_dirty(bmap);
 
 		unlock_buffer(bh);
-		nilfs_bmap_put_block(bmap, bh);
+		brelse(bh);
 
 		/* create root node at level 2 */
 		node = nilfs_btree_get_root(btree);
@@ -1669,8 +1751,7 @@ 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 {
-		if (bmap->b_pops->bpop_commit_alloc_ptr != NULL)
-			bmap->b_pops->bpop_commit_alloc_ptr(bmap, dreq);
+		nilfs_bmap_commit_alloc_ptr(bmap, dreq);
 
 		/* create root node at level 1 */
 		node = nilfs_btree_get_root(btree);
@@ -1682,8 +1763,8 @@ 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);
 }
 
 /**
@@ -1694,13 +1775,10 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
  * @keys:
  * @ptrs:
  * @n:
- * @low:
- * @high:
  */
 int nilfs_btree_convert_and_insert(struct nilfs_bmap *bmap,
 				   __u64 key, __u64 ptr,
-				   const __u64 *keys, const __u64 *ptrs,
-				   int n, __u64 low, __u64 high)
+				   const __u64 *keys, const __u64 *ptrs, int n)
 {
 	struct buffer_head *bh;
 	union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
@@ -1725,7 +1803,7 @@ int nilfs_btree_convert_and_insert(struct nilfs_bmap *bmap,
 	if (ret < 0)
 		return ret;
 	nilfs_btree_commit_convert_and_insert(bmap, key, ptr, keys, ptrs, n,
-					      low, high, di, ni, bh);
+					      di, ni, bh);
 	nilfs_bmap_add_blocks(bmap, stats.bs_nblocks);
 	return 0;
 }
@@ -1754,9 +1832,9 @@ 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_bmap_prepare_update_v(&btree->bt_bmap,
+					  &path[level].bp_oldreq,
+					  &path[level].bp_newreq);
 	if (ret < 0)
 		return ret;
 
@@ -1768,9 +1846,9 @@ 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_bmap_abort_update_v(&btree->bt_bmap,
+						  &path[level].bp_oldreq,
+						  &path[level].bp_newreq);
 			return ret;
 		}
 	}
@@ -1784,9 +1862,9 @@ static void nilfs_btree_commit_update_v(struct nilfs_btree *btree,
 {
 	struct nilfs_btree_node *parent;
 
-	nilfs_bmap_commit_update(&btree->bt_bmap,
-				 &path[level].bp_oldreq,
-				 &path[level].bp_newreq);
+	nilfs_bmap_commit_update_v(&btree->bt_bmap,
+				   &path[level].bp_oldreq,
+				   &path[level].bp_newreq);
 
 	if (buffer_nilfs_node(path[level].bp_bh)) {
 		nilfs_btnode_commit_change_key(
@@ -1805,9 +1883,9 @@ static void nilfs_btree_abort_update_v(struct nilfs_btree *btree,
 				       struct nilfs_btree_path *path,
 				       int level)
 {
-	nilfs_bmap_abort_update(&btree->bt_bmap,
-				&path[level].bp_oldreq,
-				&path[level].bp_newreq);
+	nilfs_bmap_abort_update_v(&btree->bt_bmap,
+				  &path[level].bp_oldreq,
+				  &path[level].bp_newreq);
 	if (buffer_nilfs_node(path[level].bp_bh))
 		nilfs_btnode_abort_change_key(
 			&NILFS_BMAP_I(&btree->bt_bmap)->i_btnode_cache,
@@ -1930,7 +2008,9 @@ 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);
@@ -2066,12 +2146,9 @@ 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 = btree->bt_bmap.b_pops->bpop_prepare_start_ptr(&btree->bt_bmap,
-							       &req);
-	if (ret < 0)
+	ret = nilfs_bmap_start_v(&btree->bt_bmap, &req, blocknr);
+	if (unlikely(ret < 0))
 		return ret;
-	btree->bt_bmap.b_pops->bpop_commit_start_ptr(&btree->bt_bmap,
-							&req, blocknr);
 
 	key = nilfs_btree_node_get_key(btree, parent,
 				       path[level + 1].bp_index);
@@ -2114,8 +2191,9 @@ 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);
@@ -2171,7 +2249,7 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
 		WARN_ON(ret == -ENOENT);
 		goto out;
 	}
-	ret = nilfs_bmap_get_block(&btree->bt_bmap, ptr, &bh);
+	ret = nilfs_btree_get_block(btree, ptr, &bh);
 	if (ret < 0) {
 		WARN_ON(ret == -ENOENT);
 		goto out;
@@ -2179,7 +2257,7 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
 
 	if (!buffer_dirty(bh))
 		nilfs_btnode_mark_dirty(bh);
-	nilfs_bmap_put_block(&btree->bt_bmap, bh);
+	brelse(bh);
 	if (!nilfs_bmap_dirty(&btree->bt_bmap))
 		nilfs_bmap_set_dirty(&btree->bt_bmap);
 
@@ -2191,6 +2269,7 @@ static int nilfs_btree_mark(struct nilfs_bmap *bmap, __u64 key, int level)
 
 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,
@@ -2210,6 +2289,7 @@ 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,
@@ -2227,43 +2307,13 @@ 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, __u64 low, __u64 high)
+int nilfs_btree_init(struct nilfs_bmap *bmap)
 {
-	struct nilfs_btree *btree;
-
-	btree = (struct nilfs_btree *)bmap;
 	bmap->b_ops = &nilfs_btree_ops;
-	bmap->b_low = low;
-	bmap->b_high = high;
-	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;
 }
 
 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
 {
-	bmap->b_low = NILFS_BMAP_LARGE_LOW;
-	bmap->b_high = NILFS_BMAP_LARGE_HIGH;
 	bmap->b_ops = &nilfs_btree_ops_gc;
 }
diff --git a/fs/nilfs2/btree.h b/fs/nilfs2/btree.h
index 4766deb..0e72bbb 100644
--- a/fs/nilfs2/btree.h
+++ b/fs/nilfs2/btree.h
@@ -34,28 +34,6 @@ struct nilfs_btree;
 struct nilfs_btree_path;
 
 /**
- * struct nilfs_btree_operations - B-tree operation table
- */
-struct nilfs_btree_operations {
-	__u64 (*btop_find_target)(const struct nilfs_btree *,
-				  const struct nilfs_btree_path *, __u64);
-	void (*btop_set_target)(struct nilfs_btree *, __u64, __u64);
-
-	struct the_nilfs *(*btop_get_nilfs)(struct nilfs_btree *);
-
-	int (*btop_propagate)(struct nilfs_btree *,
-			      struct nilfs_btree_path *,
-			      int,
-			      struct buffer_head *);
-	int (*btop_assign)(struct nilfs_btree *,
-			   struct nilfs_btree_path *,
-			   int,
-			   struct buffer_head **,
-			   sector_t,
-			   union nilfs_binfo *);
-};
-
-/**
  * struct nilfs_btree_node - B-tree node
  * @bn_flags: flags
  * @bn_level: level
@@ -80,13 +58,9 @@ struct nilfs_btree_node {
 /**
  * struct nilfs_btree - B-tree structure
  * @bt_bmap: bmap base structure
- * @bt_ops: B-tree operation table
  */
 struct nilfs_btree {
 	struct nilfs_bmap bt_bmap;
-
-	/* B-tree-specific members */
-	const struct nilfs_btree_operations *bt_ops;
 };
 
 
@@ -108,10 +82,9 @@ struct nilfs_btree {
 
 int nilfs_btree_path_cache_init(void);
 void nilfs_btree_path_cache_destroy(void);
-int nilfs_btree_init(struct nilfs_bmap *, __u64, __u64);
+int nilfs_btree_init(struct nilfs_bmap *);
 int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,
-				   const __u64 *, const __u64 *,
-				   int, __u64, __u64);
+				   const __u64 *, const __u64 *, int);
 void nilfs_btree_init_gc(struct nilfs_bmap *);
 
 #endif	/* _NILFS_BTREE_H */
diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index cadd36b..7d49813 100644
--- a/fs/nilfs2/cpfile.c
+++ b/fs/nilfs2/cpfile.c
@@ -295,10 +295,6 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
 		return -EINVAL;
 	}
 
-	/* cannot delete the latest checkpoint */
-	if (start == nilfs_mdt_cno(cpfile) - 1)
-		return -EPERM;
-
 	down_write(&NILFS_MDT(cpfile)->mi_sem);
 
 	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
@@ -384,9 +380,10 @@ static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
 }
 
 static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
-					  struct nilfs_cpinfo *ci, size_t nci)
+					  void *buf, unsigned cisz, size_t nci)
 {
 	struct nilfs_checkpoint *cp;
+	struct nilfs_cpinfo *ci = buf;
 	struct buffer_head *bh;
 	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
 	__u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
@@ -410,17 +407,22 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
 		kaddr = kmap_atomic(bh->b_page, KM_USER0);
 		cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
 		for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
-			if (!nilfs_checkpoint_invalid(cp))
-				nilfs_cpfile_checkpoint_to_cpinfo(
-					cpfile, cp, &ci[n++]);
+			if (!nilfs_checkpoint_invalid(cp)) {
+				nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
+								  ci);
+				ci = (void *)ci + cisz;
+				n++;
+			}
 		}
 		kunmap_atomic(kaddr, KM_USER0);
 		brelse(bh);
 	}
 
 	ret = n;
-	if (n > 0)
-		*cnop = ci[n - 1].ci_cno + 1;
+	if (n > 0) {
+		ci = (void *)ci - cisz;
+		*cnop = ci->ci_cno + 1;
+	}
 
  out:
 	up_read(&NILFS_MDT(cpfile)->mi_sem);
@@ -428,11 +430,12 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
 }
 
 static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
-					  struct nilfs_cpinfo *ci, size_t nci)
+					  void *buf, unsigned cisz, size_t nci)
 {
 	struct buffer_head *bh;
 	struct nilfs_cpfile_header *header;
 	struct nilfs_checkpoint *cp;
+	struct nilfs_cpinfo *ci = buf;
 	__u64 curr = *cnop, next;
 	unsigned long curr_blkoff, next_blkoff;
 	void *kaddr;
@@ -472,7 +475,9 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
 		if (unlikely(nilfs_checkpoint_invalid(cp) ||
 			     !nilfs_checkpoint_snapshot(cp)))
 			break;
-		nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
+		nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
+		ci = (void *)ci + cisz;
+		n++;
 		next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
 		if (next == 0)
 			break; /* reach end of the snapshot list */
@@ -511,13 +516,13 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
  */
 
 ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
-				struct nilfs_cpinfo *ci, size_t nci)
+				void *buf, unsigned cisz, size_t nci)
 {
 	switch (mode) {
 	case NILFS_CHECKPOINT:
-		return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci);
+		return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
 	case NILFS_SNAPSHOT:
-		return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
+		return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
 	default:
 		return -EINVAL;
 	}
@@ -533,20 +538,14 @@ int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
 	struct nilfs_cpinfo ci;
 	__u64 tcno = cno;
 	ssize_t nci;
-	int ret;
 
-	nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
+	nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
 	if (nci < 0)
 		return nci;
 	else if (nci == 0 || ci.ci_cno != cno)
 		return -ENOENT;
-
-	/* cannot delete the latest checkpoint nor snapshots */
-	ret = nilfs_cpinfo_snapshot(&ci);
-	if (ret < 0)
-		return ret;
-	else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
-		return -EPERM;
+	else if (nilfs_cpinfo_snapshot(&ci))
+		return -EBUSY;
 
 	return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
 }
diff --git a/fs/nilfs2/cpfile.h b/fs/nilfs2/cpfile.h
index 1a8a100..788a459 100644
--- a/fs/nilfs2/cpfile.h
+++ b/fs/nilfs2/cpfile.h
@@ -39,7 +39,7 @@ int nilfs_cpfile_delete_checkpoint(struct inode *, __u64);
 int nilfs_cpfile_change_cpmode(struct inode *, __u64, int);
 int nilfs_cpfile_is_snapshot(struct inode *, __u64);
 int nilfs_cpfile_get_stat(struct inode *, struct nilfs_cpstat *);
-ssize_t nilfs_cpfile_get_cpinfo(struct inode *, __u64 *, int,
-				struct nilfs_cpinfo *, size_t);
+ssize_t nilfs_cpfile_get_cpinfo(struct inode *, __u64 *, int, void *, unsigned,
+				size_t);
 
 #endif	/* _NILFS_CPFILE_H */
diff --git a/fs/nilfs2/dat.c b/fs/nilfs2/dat.c
index bb8a581..0b2710e 100644
--- a/fs/nilfs2/dat.c
+++ b/fs/nilfs2/dat.c
@@ -92,21 +92,6 @@ void nilfs_dat_abort_alloc(struct inode *dat, struct nilfs_palloc_req *req)
 	nilfs_palloc_abort_alloc_entry(dat, req);
 }
 
-int nilfs_dat_prepare_free(struct inode *dat, struct nilfs_palloc_req *req)
-{
-	int ret;
-
-	ret = nilfs_palloc_prepare_free_entry(dat, req);
-	if (ret < 0)
-		return ret;
-	ret = nilfs_dat_prepare_entry(dat, req, 0);
-	if (ret < 0) {
-		nilfs_palloc_abort_free_entry(dat, req);
-		return ret;
-	}
-	return 0;
-}
-
 void nilfs_dat_commit_free(struct inode *dat, struct nilfs_palloc_req *req)
 {
 	struct nilfs_dat_entry *entry;
@@ -391,36 +376,37 @@ int nilfs_dat_translate(struct inode *dat, __u64 vblocknr, sector_t *blocknrp)
 	return ret;
 }
 
-ssize_t nilfs_dat_get_vinfo(struct inode *dat, struct nilfs_vinfo *vinfo,
+ssize_t nilfs_dat_get_vinfo(struct inode *dat, void *buf, unsigned visz,
 			    size_t nvi)
 {
 	struct buffer_head *entry_bh;
 	struct nilfs_dat_entry *entry;
+	struct nilfs_vinfo *vinfo = buf;
 	__u64 first, last;
 	void *kaddr;
 	unsigned long entries_per_block = NILFS_MDT(dat)->mi_entries_per_block;
 	int i, j, n, ret;
 
 	for (i = 0; i < nvi; i += n) {
-		ret = nilfs_palloc_get_entry_block(dat, vinfo[i].vi_vblocknr,
+		ret = nilfs_palloc_get_entry_block(dat, vinfo->vi_vblocknr,
 						   0, &entry_bh);
 		if (ret < 0)
 			return ret;
 		kaddr = kmap_atomic(entry_bh->b_page, KM_USER0);
 		/* last virtual block number in this block */
-		first = vinfo[i].vi_vblocknr;
+		first = vinfo->vi_vblocknr;
 		do_div(first, entries_per_block);
 		first *= entries_per_block;
 		last = first + entries_per_block - 1;
 		for (j = i, n = 0;
-		     j < nvi && vinfo[j].vi_vblocknr >= first &&
-			     vinfo[j].vi_vblocknr <= last;
-		     j++, n++) {
+		     j < nvi && vinfo->vi_vblocknr >= first &&
+			     vinfo->vi_vblocknr <= last;
+		     j++, n++, vinfo = (void *)vinfo + visz) {
 			entry = nilfs_palloc_block_get_entry(
-				dat, vinfo[j].vi_vblocknr, entry_bh, kaddr);
-			vinfo[j].vi_start = le64_to_cpu(entry->de_start);
-			vinfo[j].vi_end = le64_to_cpu(entry->de_end);
-			vinfo[j].vi_blocknr = le64_to_cpu(entry->de_blocknr);
+				dat, vinfo->vi_vblocknr, entry_bh, kaddr);
+			vinfo->vi_start = le64_to_cpu(entry->de_start);
+			vinfo->vi_end = le64_to_cpu(entry->de_end);
+			vinfo->vi_blocknr = le64_to_cpu(entry->de_blocknr);
 		}
 		kunmap_atomic(kaddr, KM_USER0);
 		brelse(entry_bh);
diff --git a/fs/nilfs2/dat.h b/fs/nilfs2/dat.h
index d956065..d328b81 100644
--- a/fs/nilfs2/dat.h
+++ b/fs/nilfs2/dat.h
@@ -47,6 +47,6 @@ void nilfs_dat_abort_end(struct inode *, struct nilfs_palloc_req *);
 int nilfs_dat_mark_dirty(struct inode *, __u64);
 int nilfs_dat_freev(struct inode *, __u64 *, size_t);
 int nilfs_dat_move(struct inode *, __u64, sector_t);
-ssize_t nilfs_dat_get_vinfo(struct inode *, struct nilfs_vinfo *, size_t);
+ssize_t nilfs_dat_get_vinfo(struct inode *, void *, unsigned, size_t);
 
 #endif	/* _NILFS_DAT_H */
diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index c6379e4..342d976 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -25,6 +25,7 @@
 #include "page.h"
 #include "direct.h"
 #include "alloc.h"
+#include "dat.h"
 
 static inline __le64 *nilfs_direct_dptrs(const struct nilfs_direct *direct)
 {
@@ -62,6 +63,47 @@ static int nilfs_direct_lookup(const struct nilfs_bmap *bmap,
 	return 0;
 }
 
+static int nilfs_direct_lookup_contig(const struct nilfs_bmap *bmap,
+				      __u64 key, __u64 *ptrp,
+				      unsigned maxblocks)
+{
+	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
+	struct inode *dat = NULL;
+	__u64 ptr, ptr2;
+	sector_t blocknr;
+	int ret, cnt;
+
+	if (key > NILFS_DIRECT_KEY_MAX ||
+	    (ptr = nilfs_direct_get_ptr(direct, key)) ==
+	    NILFS_BMAP_INVALID_PTR)
+		return -ENOENT;
+
+	if (NILFS_BMAP_USE_VBN(bmap)) {
+		dat = nilfs_bmap_get_dat(bmap);
+		ret = nilfs_dat_translate(dat, ptr, &blocknr);
+		if (ret < 0)
+			return ret;
+		ptr = blocknr;
+	}
+
+	maxblocks = min_t(unsigned, maxblocks, NILFS_DIRECT_KEY_MAX - key + 1);
+	for (cnt = 1; cnt < maxblocks &&
+		     (ptr2 = nilfs_direct_get_ptr(direct, key + cnt)) !=
+		     NILFS_BMAP_INVALID_PTR;
+	     cnt++) {
+		if (dat) {
+			ret = nilfs_dat_translate(dat, ptr2, &blocknr);
+			if (ret < 0)
+				return ret;
+			ptr2 = blocknr;
+		}
+		if (ptr2 != ptr + cnt)
+			break;
+	}
+	*ptrp = ptr;
+	return cnt;
+}
+
 static __u64
 nilfs_direct_find_target_v(const struct nilfs_direct *direct, __u64 key)
 {
@@ -90,10 +132,9 @@ static int nilfs_direct_prepare_insert(struct nilfs_direct *direct,
 {
 	int ret;
 
-	if (direct->d_ops->dop_find_target != NULL)
-		req->bpr_ptr = direct->d_ops->dop_find_target(direct, key);
-	ret = direct->d_bmap.b_pops->bpop_prepare_alloc_ptr(&direct->d_bmap,
-							       req);
+	if (NILFS_BMAP_USE_VBN(&direct->d_bmap))
+		req->bpr_ptr = nilfs_direct_find_target_v(direct, key);
+	ret = nilfs_bmap_prepare_alloc_ptr(&direct->d_bmap, req);
 	if (ret < 0)
 		return ret;
 
@@ -111,16 +152,14 @@ static void nilfs_direct_commit_insert(struct nilfs_direct *direct,
 	bh = (struct buffer_head *)((unsigned long)ptr);
 	set_buffer_nilfs_volatile(bh);
 
-	if (direct->d_bmap.b_pops->bpop_commit_alloc_ptr != NULL)
-		direct->d_bmap.b_pops->bpop_commit_alloc_ptr(
-			&direct->d_bmap, req);
+	nilfs_bmap_commit_alloc_ptr(&direct->d_bmap, req);
 	nilfs_direct_set_ptr(direct, key, req->bpr_ptr);
 
 	if (!nilfs_bmap_dirty(&direct->d_bmap))
 		nilfs_bmap_set_dirty(&direct->d_bmap);
 
-	if (direct->d_ops->dop_set_target != NULL)
-		direct->d_ops->dop_set_target(direct, key, req->bpr_ptr);
+	if (NILFS_BMAP_USE_VBN(&direct->d_bmap))
+		nilfs_direct_set_target_v(direct, key, req->bpr_ptr);
 }
 
 static int nilfs_direct_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
@@ -152,25 +191,18 @@ static int nilfs_direct_prepare_delete(struct nilfs_direct *direct,
 {
 	int ret;
 
-	if (direct->d_bmap.b_pops->bpop_prepare_end_ptr != NULL) {
-		req->bpr_ptr = nilfs_direct_get_ptr(direct, key);
-		ret = direct->d_bmap.b_pops->bpop_prepare_end_ptr(
-			&direct->d_bmap, req);
-		if (ret < 0)
-			return ret;
-	}
-
-	stats->bs_nblocks = 1;
-	return 0;
+	req->bpr_ptr = nilfs_direct_get_ptr(direct, key);
+	ret = nilfs_bmap_prepare_end_ptr(&direct->d_bmap, req);
+	if (!ret)
+		stats->bs_nblocks = 1;
+	return ret;
 }
 
 static void nilfs_direct_commit_delete(struct nilfs_direct *direct,
 				       union nilfs_bmap_ptr_req *req,
 				       __u64 key)
 {
-	if (direct->d_bmap.b_pops->bpop_commit_end_ptr != NULL)
-		direct->d_bmap.b_pops->bpop_commit_end_ptr(
-			&direct->d_bmap, req);
+	nilfs_bmap_commit_end_ptr(&direct->d_bmap, req);
 	nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
 }
 
@@ -244,8 +276,7 @@ static int nilfs_direct_gather_data(struct nilfs_bmap *bmap,
 }
 
 int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
-				    __u64 key, __u64 *keys, __u64 *ptrs,
-				    int n, __u64 low, __u64 high)
+				    __u64 key, __u64 *keys, __u64 *ptrs, int n)
 {
 	struct nilfs_direct *direct;
 	__le64 *dptrs;
@@ -275,8 +306,7 @@ int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
 			dptrs[i] = NILFS_BMAP_INVALID_PTR;
 	}
 
-	nilfs_direct_init(bmap, low, high);
-
+	nilfs_direct_init(bmap);
 	return 0;
 }
 
@@ -293,11 +323,11 @@ static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
 	if (!buffer_nilfs_volatile(bh)) {
 		oldreq.bpr_ptr = ptr;
 		newreq.bpr_ptr = ptr;
-		ret = nilfs_bmap_prepare_update(&direct->d_bmap, &oldreq,
-						&newreq);
+		ret = nilfs_bmap_prepare_update_v(&direct->d_bmap, &oldreq,
+						  &newreq);
 		if (ret < 0)
 			return ret;
-		nilfs_bmap_commit_update(&direct->d_bmap, &oldreq, &newreq);
+		nilfs_bmap_commit_update_v(&direct->d_bmap, &oldreq, &newreq);
 		set_buffer_nilfs_volatile(bh);
 		nilfs_direct_set_ptr(direct, key, newreq.bpr_ptr);
 	} else
@@ -309,12 +339,10 @@ static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
 static int nilfs_direct_propagate(const struct nilfs_bmap *bmap,
 				  struct buffer_head *bh)
 {
-	struct nilfs_direct *direct;
+	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
 
-	direct = (struct nilfs_direct *)bmap;
-	return (direct->d_ops->dop_propagate != NULL) ?
-		direct->d_ops->dop_propagate(direct, bh) :
-		0;
+	return NILFS_BMAP_USE_VBN(bmap) ?
+		nilfs_direct_propagate_v(direct, bh) : 0;
 }
 
 static int nilfs_direct_assign_v(struct nilfs_direct *direct,
@@ -327,12 +355,9 @@ static int nilfs_direct_assign_v(struct nilfs_direct *direct,
 	int ret;
 
 	req.bpr_ptr = ptr;
-	ret = direct->d_bmap.b_pops->bpop_prepare_start_ptr(
-		&direct->d_bmap, &req);
-	if (ret < 0)
+	ret = nilfs_bmap_start_v(&direct->d_bmap, &req, blocknr);
+	if (unlikely(ret < 0))
 		return ret;
-	direct->d_bmap.b_pops->bpop_commit_start_ptr(&direct->d_bmap,
-						     &req, blocknr);
 
 	binfo->bi_v.bi_vblocknr = nilfs_bmap_ptr_to_dptr(ptr);
 	binfo->bi_v.bi_blkoff = nilfs_bmap_key_to_dkey(key);
@@ -377,12 +402,14 @@ static int nilfs_direct_assign(struct nilfs_bmap *bmap,
 		return -EINVAL;
 	}
 
-	return direct->d_ops->dop_assign(direct, key, ptr, bh,
-					 blocknr, binfo);
+	return NILFS_BMAP_USE_VBN(bmap) ?
+		nilfs_direct_assign_v(direct, key, ptr, bh, blocknr, binfo) :
+		nilfs_direct_assign_p(direct, key, ptr, bh, blocknr, binfo);
 }
 
 static const struct nilfs_bmap_operations nilfs_direct_ops = {
 	.bop_lookup		=	nilfs_direct_lookup,
+	.bop_lookup_contig	=	nilfs_direct_lookup_contig,
 	.bop_insert		=	nilfs_direct_insert,
 	.bop_delete		=	nilfs_direct_delete,
 	.bop_clear		=	NULL,
@@ -401,36 +428,8 @@ static const struct nilfs_bmap_operations nilfs_direct_ops = {
 };
 
 
-static const struct nilfs_direct_operations nilfs_direct_ops_v = {
-	.dop_find_target	=	nilfs_direct_find_target_v,
-	.dop_set_target		=	nilfs_direct_set_target_v,
-	.dop_propagate		=	nilfs_direct_propagate_v,
-	.dop_assign		=	nilfs_direct_assign_v,
-};
-
-static const struct nilfs_direct_operations nilfs_direct_ops_p = {
-	.dop_find_target	=	NULL,
-	.dop_set_target		=	NULL,
-	.dop_propagate		=	NULL,
-	.dop_assign		=	nilfs_direct_assign_p,
-};
-
-int nilfs_direct_init(struct nilfs_bmap *bmap, __u64 low, __u64 high)
+int nilfs_direct_init(struct nilfs_bmap *bmap)
 {
-	struct nilfs_direct *direct;
-
-	direct = (struct nilfs_direct *)bmap;
 	bmap->b_ops = &nilfs_direct_ops;
-	bmap->b_low = low;
-	bmap->b_high = high;
-	switch (bmap->b_inode->i_ino) {
-	case NILFS_DAT_INO:
-		direct->d_ops = &nilfs_direct_ops_p;
-		break;
-	default:
-		direct->d_ops = &nilfs_direct_ops_v;
-		break;
-	}
-
 	return 0;
 }
diff --git a/fs/nilfs2/direct.h b/fs/nilfs2/direct.h
index 45d2c5c..a5ffd66 100644
--- a/fs/nilfs2/direct.h
+++ b/fs/nilfs2/direct.h
@@ -31,18 +31,6 @@
 struct nilfs_direct;
 
 /**
- * struct nilfs_direct_operations - direct mapping operation table
- */
-struct nilfs_direct_operations {
-	__u64 (*dop_find_target)(const struct nilfs_direct *, __u64);
-	void (*dop_set_target)(struct nilfs_direct *, __u64, __u64);
-	int (*dop_propagate)(struct nilfs_direct *, struct buffer_head *);
-	int (*dop_assign)(struct nilfs_direct *, __u64, __u64,
-			  struct buffer_head **, sector_t,
-			  union nilfs_binfo *);
-};
-
-/**
  * struct nilfs_direct_node - direct node
  * @dn_flags: flags
  * @dn_pad: padding
@@ -55,13 +43,9 @@ struct nilfs_direct_node {
 /**
  * struct nilfs_direct - direct mapping
  * @d_bmap: bmap structure
- * @d_ops: direct mapping operation table
  */
 struct nilfs_direct {
 	struct nilfs_bmap d_bmap;
-
-	/* direct-mapping-specific members */
-	const struct nilfs_direct_operations *d_ops;
 };
 
 
@@ -70,9 +54,9 @@ struct nilfs_direct {
 #define NILFS_DIRECT_KEY_MAX	(NILFS_DIRECT_NBLOCKS - 1)
 
 
-int nilfs_direct_init(struct nilfs_bmap *, __u64, __u64);
+int nilfs_direct_init(struct nilfs_bmap *);
 int nilfs_direct_delete_and_convert(struct nilfs_bmap *, __u64, __u64 *,
-				    __u64 *, int, __u64, __u64);
+				    __u64 *, int);
 
 
 #endif	/* _NILFS_DIRECT_H */
diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index 19d2102..1b3c2bb 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -52,8 +52,9 @@
 #include "dat.h"
 #include "ifile.h"
 
-static struct address_space_operations def_gcinode_aops = {};
-/* XXX need def_gcinode_iops/fops? */
+static struct address_space_operations def_gcinode_aops = {
+	.sync_page		= block_sync_page,
+};
 
 /*
  * nilfs_gccache_submit_read_data() - add data buffer and submit read request
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 49ab4a4..2696d6b 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -43,22 +43,23 @@
  *
  * This function does not issue actual read request of the specified data
  * block. It is done by VFS.
- * Bulk read for direct-io is not supported yet. (should be supported)
  */
 int nilfs_get_block(struct inode *inode, sector_t blkoff,
 		    struct buffer_head *bh_result, int create)
 {
 	struct nilfs_inode_info *ii = NILFS_I(inode);
-	unsigned long blknum = 0;
+	__u64 blknum = 0;
 	int err = 0, ret;
 	struct inode *dat = nilfs_dat_inode(NILFS_I_NILFS(inode));
+	unsigned maxblocks = bh_result->b_size >> inode->i_blkbits;
 
-	/* This exclusion control is a workaround; should be revised */
-	down_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */
-	ret = nilfs_bmap_lookup(ii->i_bmap, (unsigned long)blkoff, &blknum);
-	up_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */
-	if (ret == 0) {	/* found */
+	down_read(&NILFS_MDT(dat)->mi_sem);
+	ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
+	up_read(&NILFS_MDT(dat)->mi_sem);
+	if (ret >= 0) {	/* found */
 		map_bh(bh_result, inode->i_sb, blknum);
+		if (ret > 0)
+			bh_result->b_size = (ret << inode->i_blkbits);
 		goto out;
 	}
 	/* data block was not found */
@@ -240,7 +241,7 @@ nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 struct address_space_operations nilfs_aops = {
 	.writepage		= nilfs_writepage,
 	.readpage		= nilfs_readpage,
-	/* .sync_page		= nilfs_sync_page, */
+	.sync_page		= block_sync_page,
 	.writepages		= nilfs_writepages,
 	.set_page_dirty		= nilfs_set_page_dirty,
 	.readpages		= nilfs_readpages,
@@ -249,6 +250,7 @@ struct address_space_operations nilfs_aops = {
 	/* .releasepage		= nilfs_releasepage, */
 	.invalidatepage		= block_invalidatepage,
 	.direct_IO		= nilfs_direct_IO,
+	.is_partially_uptodate  = block_is_partially_uptodate,
 };
 
 struct inode *nilfs_new_inode(struct inode *dir, int mode)
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index d6759b9..6ea5f87 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -152,7 +152,7 @@ nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 
 	down_read(&nilfs->ns_segctor_sem);
 	ret = nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, posp, flags, buf,
-				      nmembs);
+				      size, nmembs);
 	up_read(&nilfs->ns_segctor_sem);
 	return ret;
 }
@@ -182,7 +182,8 @@ nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 	int ret;
 
 	down_read(&nilfs->ns_segctor_sem);
-	ret = nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, nmembs);
+	ret = nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, size,
+				      nmembs);
 	up_read(&nilfs->ns_segctor_sem);
 	return ret;
 }
@@ -212,7 +213,7 @@ nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 	int ret;
 
 	down_read(&nilfs->ns_segctor_sem);
-	ret = nilfs_dat_get_vinfo(nilfs_dat_inode(nilfs), buf, nmembs);
+	ret = nilfs_dat_get_vinfo(nilfs_dat_inode(nilfs), buf, size, nmembs);
 	up_read(&nilfs->ns_segctor_sem);
 	return ret;
 }
@@ -435,24 +436,6 @@ static int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs,
 	return nmembs;
 }
 
-static int nilfs_ioctl_free_segments(struct the_nilfs *nilfs,
-				     struct nilfs_argv *argv, void *buf)
-{
-	size_t nmembs = argv->v_nmembs;
-	struct nilfs_sb_info *sbi = nilfs->ns_writer;
-	int ret;
-
-	if (unlikely(!sbi)) {
-		/* never happens because called for a writable mount */
-		WARN_ON(1);
-		return -EROFS;
-	}
-	ret = nilfs_segctor_add_segments_to_be_freed(
-		NILFS_SC(sbi), buf, nmembs);
-
-	return (ret < 0) ? ret : nmembs;
-}
-
 int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
 				       struct nilfs_argv *argv, void **kbufs)
 {
@@ -491,14 +474,6 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
 		msg = "cannot mark copying blocks dirty";
 		goto failed;
 	}
-	ret = nilfs_ioctl_free_segments(nilfs, &argv[4], kbufs[4]);
-	if (ret < 0) {
-		/*
-		 * can safely abort because this operation is atomic.
-		 */
-		msg = "cannot set segments to be freed";
-		goto failed;
-	}
 	return 0;
 
  failed:
@@ -615,7 +590,7 @@ static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
 	if (copy_from_user(&argv, argp, sizeof(argv)))
 		return -EFAULT;
 
-	if (argv.v_size != membsz)
+	if (argv.v_size < membsz)
 		return -EINVAL;
 
 	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), dofunc);
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index bb78745..3d3ddb3 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -430,6 +430,7 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 
 static struct address_space_operations def_mdt_aops = {
 	.writepage		= nilfs_mdt_write_page,
+	.sync_page		= block_sync_page,
 };
 
 static struct inode_operations def_mdt_iops;
@@ -449,7 +450,7 @@ struct inode *
 nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 		     ino_t ino, gfp_t gfp_mask)
 {
-	struct inode *inode = nilfs_alloc_inode(sb);
+	struct inode *inode = nilfs_alloc_inode_common(nilfs);
 
 	if (!inode)
 		return NULL;
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index da6fc0b..edf6a59 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -263,6 +263,7 @@ extern void nilfs_dirty_inode(struct inode *);
 extern struct dentry *nilfs_get_parent(struct dentry *);
 
 /* super.c */
+extern struct inode *nilfs_alloc_inode_common(struct the_nilfs *);
 extern struct inode *nilfs_alloc_inode(struct super_block *);
 extern void nilfs_destroy_inode(struct inode *);
 extern void nilfs_error(struct super_block *, const char *, const char *, ...)
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index 57afa9d..d80cc71 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -28,7 +28,6 @@
 #include "segment.h"
 #include "sufile.h"
 #include "page.h"
-#include "seglist.h"
 #include "segbuf.h"
 
 /*
@@ -395,6 +394,24 @@ static void dispose_recovery_list(struct list_head *head)
 	}
 }
 
+struct nilfs_segment_entry {
+	struct list_head	list;
+	__u64			segnum;
+};
+
+static int nilfs_segment_list_add(struct list_head *head, __u64 segnum)
+{
+	struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
+
+	if (unlikely(!ent))
+		return -ENOMEM;
+
+	ent->segnum = segnum;
+	INIT_LIST_HEAD(&ent->list);
+	list_add_tail(&ent->list, head);
+	return 0;
+}
+
 void nilfs_dispose_segment_list(struct list_head *head)
 {
 	while (!list_empty(head)) {
@@ -402,7 +419,7 @@ void nilfs_dispose_segment_list(struct list_head *head)
 			= list_entry(head->next,
 				     struct nilfs_segment_entry, list);
 		list_del(&ent->list);
-		nilfs_free_segment_entry(ent);
+		kfree(ent);
 	}
 }
 
@@ -431,12 +448,10 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
 	if (unlikely(err))
 		goto failed;
 
-	err = -ENOMEM;
 	for (i = 1; i < 4; i++) {
-		ent = nilfs_alloc_segment_entry(segnum[i]);
-		if (unlikely(!ent))
+		err = nilfs_segment_list_add(head, segnum[i]);
+		if (unlikely(err))
 			goto failed;
-		list_add_tail(&ent->list, head);
 	}
 
 	/*
@@ -450,7 +465,7 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
 				goto failed;
 		}
 		list_del(&ent->list);
-		nilfs_free_segment_entry(ent);
+		kfree(ent);
 	}
 
 	/* Allocate new segments for recovery */
@@ -791,7 +806,6 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi,
 	u64 seg_seq;
 	__u64 segnum, nextnum = 0;
 	__u64 cno;
-	struct nilfs_segment_entry *ent;
 	LIST_HEAD(segments);
 	int empty_seg = 0, scan_newer = 0;
 	int ret;
@@ -892,12 +906,9 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi,
 		if (empty_seg++)
 			goto super_root_found; /* found a valid super root */
 
-		ent = nilfs_alloc_segment_entry(segnum);
-		if (unlikely(!ent)) {
-			ret = -ENOMEM;
+		ret = nilfs_segment_list_add(&segments, segnum);
+		if (unlikely(ret))
 			goto failed;
-		}
-		list_add_tail(&ent->list, &segments);
 
 		seg_seq++;
 		segnum = nextnum;
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 1e68821..9e3fe17 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -26,7 +26,6 @@
 #include <linux/crc32.h>
 #include "page.h"
 #include "segbuf.h"
-#include "seglist.h"
 
 
 static struct kmem_cache *nilfs_segbuf_cachep;
@@ -394,7 +393,7 @@ int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 		 * Last BIO is always sent through the following
 		 * submission.
 		 */
-		rw |= (1 << BIO_RW_SYNCIO);
+		rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
 		res = nilfs_submit_seg_bio(wi, rw);
 		if (unlikely(res))
 			goto failed_bio;
diff --git a/fs/nilfs2/seglist.h b/fs/nilfs2/seglist.h
deleted file mode 100644
index d39df91..0000000
--- a/fs/nilfs2/seglist.h
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * seglist.h - expediential structure and routines to handle list of segments
- *             (would be removed in a future release)
- *
- * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- * Written by Ryusuke Konishi <ryusuke@osrg.net>
- *
- */
-#ifndef _NILFS_SEGLIST_H
-#define _NILFS_SEGLIST_H
-
-#include <linux/fs.h>
-#include <linux/buffer_head.h>
-#include <linux/nilfs2_fs.h>
-#include "sufile.h"
-
-struct nilfs_segment_entry {
-	__u64			segnum;
-
-#define NILFS_SLH_FREED		0x0001	/* The segment was freed provisonally.
-					   It must be cancelled if
-					   construction aborted */
-
-	unsigned		flags;
-	struct list_head	list;
-	struct buffer_head     *bh_su;
-	struct nilfs_segment_usage *raw_su;
-};
-
-
-void nilfs_dispose_segment_list(struct list_head *);
-
-static inline struct nilfs_segment_entry *
-nilfs_alloc_segment_entry(__u64 segnum)
-{
-	struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
-
-	if (likely(ent)) {
-		ent->segnum = segnum;
-		ent->flags = 0;
-		ent->bh_su = NULL;
-		ent->raw_su = NULL;
-		INIT_LIST_HEAD(&ent->list);
-	}
-	return ent;
-}
-
-static inline int nilfs_open_segment_entry(struct nilfs_segment_entry *ent,
-					   struct inode *sufile)
-{
-	return nilfs_sufile_get_segment_usage(sufile, ent->segnum,
-					      &ent->raw_su, &ent->bh_su);
-}
-
-static inline void nilfs_close_segment_entry(struct nilfs_segment_entry *ent,
-					     struct inode *sufile)
-{
-	if (!ent->bh_su)
-		return;
-	nilfs_sufile_put_segment_usage(sufile, ent->segnum, ent->bh_su);
-	ent->bh_su = NULL;
-	ent->raw_su = NULL;
-}
-
-static inline void nilfs_free_segment_entry(struct nilfs_segment_entry *ent)
-{
-	kfree(ent);
-}
-
-#endif /* _NILFS_SEGLIST_H */
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 22c7f65..aa97754 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -39,7 +39,6 @@
 #include "sufile.h"
 #include "cpfile.h"
 #include "ifile.h"
-#include "seglist.h"
 #include "segbuf.h"
 
 
@@ -79,7 +78,8 @@ enum {
 /* State flags of collection */
 #define NILFS_CF_NODE		0x0001	/* Collecting node blocks */
 #define NILFS_CF_IFILE_STARTED	0x0002	/* IFILE stage has started */
-#define NILFS_CF_HISTORY_MASK	(NILFS_CF_IFILE_STARTED)
+#define NILFS_CF_SUFREED	0x0004	/* segment usages has been freed */
+#define NILFS_CF_HISTORY_MASK	(NILFS_CF_IFILE_STARTED | NILFS_CF_SUFREED)
 
 /* Operations depending on the construction mode and file type */
 struct nilfs_sc_operations {
@@ -810,7 +810,7 @@ static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 {
 	return list_empty(&sci->sc_dirty_files) &&
 		!test_bit(NILFS_SC_DIRTY, &sci->sc_flags) &&
-		list_empty(&sci->sc_cleaning_segments) &&
+		sci->sc_nfreesegs == 0 &&
 		(!nilfs_doing_gc() || list_empty(&sci->sc_gc_inodes));
 }
 
@@ -1005,44 +1005,6 @@ static void nilfs_drop_collected_inodes(struct list_head *head)
 	}
 }
 
-static void nilfs_segctor_cancel_free_segments(struct nilfs_sc_info *sci,
-					       struct inode *sufile)
-
-{
-	struct list_head *head = &sci->sc_cleaning_segments;
-	struct nilfs_segment_entry *ent;
-	int err;
-
-	list_for_each_entry(ent, head, list) {
-		if (!(ent->flags & NILFS_SLH_FREED))
-			break;
-		err = nilfs_sufile_cancel_free(sufile, ent->segnum);
-		WARN_ON(err); /* do not happen */
-		ent->flags &= ~NILFS_SLH_FREED;
-	}
-}
-
-static int nilfs_segctor_prepare_free_segments(struct nilfs_sc_info *sci,
-					       struct inode *sufile)
-{
-	struct list_head *head = &sci->sc_cleaning_segments;
-	struct nilfs_segment_entry *ent;
-	int err;
-
-	list_for_each_entry(ent, head, list) {
-		err = nilfs_sufile_free(sufile, ent->segnum);
-		if (unlikely(err))
-			return err;
-		ent->flags |= NILFS_SLH_FREED;
-	}
-	return 0;
-}
-
-static void nilfs_segctor_commit_free_segments(struct nilfs_sc_info *sci)
-{
-	nilfs_dispose_segment_list(&sci->sc_cleaning_segments);
-}
-
 static int nilfs_segctor_apply_buffers(struct nilfs_sc_info *sci,
 				       struct inode *inode,
 				       struct list_head *listp,
@@ -1161,6 +1123,7 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 	struct the_nilfs *nilfs = sbi->s_nilfs;
 	struct list_head *head;
 	struct nilfs_inode_info *ii;
+	size_t ndone;
 	int err = 0;
 
 	switch (sci->sc_stage.scnt) {
@@ -1250,10 +1213,16 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 			break;
 		sci->sc_stage.scnt++;  /* Fall through */
 	case NILFS_ST_SUFILE:
-		err = nilfs_segctor_prepare_free_segments(sci,
-							  nilfs->ns_sufile);
-		if (unlikely(err))
+		err = nilfs_sufile_freev(nilfs->ns_sufile, sci->sc_freesegs,
+					 sci->sc_nfreesegs, &ndone);
+		if (unlikely(err)) {
+			nilfs_sufile_cancel_freev(nilfs->ns_sufile,
+						  sci->sc_freesegs, ndone,
+						  NULL);
 			break;
+		}
+		sci->sc_stage.flags |= NILFS_CF_SUFREED;
+
 		err = nilfs_segctor_scan_file(sci, nilfs->ns_sufile,
 					      &nilfs_sc_file_ops);
 		if (unlikely(err))
@@ -1486,7 +1455,15 @@ static void nilfs_segctor_end_construction(struct nilfs_sc_info *sci,
 {
 	if (unlikely(err)) {
 		nilfs_segctor_free_incomplete_segments(sci, nilfs);
-		nilfs_segctor_cancel_free_segments(sci, nilfs->ns_sufile);
+		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
+			int ret;
+
+			ret = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
+							sci->sc_freesegs,
+							sci->sc_nfreesegs,
+							NULL);
+			WARN_ON(ret); /* do not happen */
+		}
 	}
 	nilfs_segctor_clear_segment_buffers(sci);
 }
@@ -1585,7 +1562,13 @@ static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
 		if (mode != SC_LSEG_SR || sci->sc_stage.scnt < NILFS_ST_CPFILE)
 			break;
 
-		nilfs_segctor_cancel_free_segments(sci, nilfs->ns_sufile);
+		if (sci->sc_stage.flags & NILFS_CF_SUFREED) {
+			err = nilfs_sufile_cancel_freev(nilfs->ns_sufile,
+							sci->sc_freesegs,
+							sci->sc_nfreesegs,
+							NULL);
+			WARN_ON(err); /* do not happen */
+		}
 		nilfs_segctor_clear_segment_buffers(sci);
 
 		err = nilfs_segctor_extend_segments(sci, nilfs, nadd);
@@ -2224,10 +2207,8 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 		nilfs_segctor_complete_write(sci);
 
 		/* Commit segments */
-		if (has_sr) {
-			nilfs_segctor_commit_free_segments(sci);
+		if (has_sr)
 			nilfs_segctor_clear_metadata_dirty(sci);
-		}
 
 		nilfs_segctor_end_construction(sci, nilfs, 0);
 
@@ -2301,48 +2282,6 @@ void nilfs_flush_segment(struct super_block *sb, ino_t ino)
 					/* assign bit 0 to data files */
 }
 
-int nilfs_segctor_add_segments_to_be_freed(struct nilfs_sc_info *sci,
-					   __u64 *segnum, size_t nsegs)
-{
-	struct nilfs_segment_entry *ent;
-	struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
-	struct inode *sufile = nilfs->ns_sufile;
-	LIST_HEAD(list);
-	__u64 *pnum;
-	size_t i;
-	int err;
-
-	for (pnum = segnum, i = 0; i < nsegs; pnum++, i++) {
-		ent = nilfs_alloc_segment_entry(*pnum);
-		if (unlikely(!ent)) {
-			err = -ENOMEM;
-			goto failed;
-		}
-		list_add_tail(&ent->list, &list);
-
-		err = nilfs_open_segment_entry(ent, sufile);
-		if (unlikely(err))
-			goto failed;
-
-		if (unlikely(!nilfs_segment_usage_dirty(ent->raw_su)))
-			printk(KERN_WARNING "NILFS: unused segment is "
-			       "requested to be cleaned (segnum=%llu)\n",
-			       (unsigned long long)ent->segnum);
-		nilfs_close_segment_entry(ent, sufile);
-	}
-	list_splice(&list, sci->sc_cleaning_segments.prev);
-	return 0;
-
- failed:
-	nilfs_dispose_segment_list(&list);
-	return err;
-}
-
-void nilfs_segctor_clear_segments_to_be_freed(struct nilfs_sc_info *sci)
-{
-	nilfs_dispose_segment_list(&sci->sc_cleaning_segments);
-}
-
 struct nilfs_segctor_wait_request {
 	wait_queue_t	wq;
 	__u32		seq;
@@ -2607,10 +2546,13 @@ int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
 	err = nilfs_init_gcdat_inode(nilfs);
 	if (unlikely(err))
 		goto out_unlock;
+
 	err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
 	if (unlikely(err))
 		goto out_unlock;
 
+	sci->sc_freesegs = kbufs[4];
+	sci->sc_nfreesegs = argv[4].v_nmembs;
 	list_splice_init(&nilfs->ns_gc_inodes, sci->sc_gc_inodes.prev);
 
 	for (;;) {
@@ -2629,6 +2571,8 @@ int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
 	}
 
  out_unlock:
+	sci->sc_freesegs = NULL;
+	sci->sc_nfreesegs = 0;
 	nilfs_clear_gcdat_inode(nilfs);
 	nilfs_transaction_unlock(sbi);
 	return err;
@@ -2835,7 +2779,6 @@ static struct nilfs_sc_info *nilfs_segctor_new(struct nilfs_sb_info *sbi)
 	INIT_LIST_HEAD(&sci->sc_dirty_files);
 	INIT_LIST_HEAD(&sci->sc_segbufs);
 	INIT_LIST_HEAD(&sci->sc_gc_inodes);
-	INIT_LIST_HEAD(&sci->sc_cleaning_segments);
 	INIT_LIST_HEAD(&sci->sc_copied_buffers);
 
 	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
@@ -2901,9 +2844,6 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 		nilfs_dispose_list(sbi, &sci->sc_dirty_files, 1);
 	}
 
-	if (!list_empty(&sci->sc_cleaning_segments))
-		nilfs_dispose_segment_list(&sci->sc_cleaning_segments);
-
 	WARN_ON(!list_empty(&sci->sc_segbufs));
 
 	down_write(&sbi->s_nilfs->ns_segctor_sem);
diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index 476bdd5..0d2a475 100644
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -90,8 +90,9 @@ struct nilfs_segsum_pointer {
  * @sc_nblk_inc: Block count of current generation
  * @sc_dirty_files: List of files to be written
  * @sc_gc_inodes: List of GC inodes having blocks to be written
- * @sc_cleaning_segments: List of segments to be freed through construction
  * @sc_copied_buffers: List of copied buffers (buffer heads) to freeze data
+ * @sc_freesegs: array of segment numbers to be freed
+ * @sc_nfreesegs: number of segments on @sc_freesegs
  * @sc_dsync_inode: inode whose data pages are written for a sync operation
  * @sc_dsync_start: start byte offset of data pages
  * @sc_dsync_end: end byte offset of data pages (inclusive)
@@ -131,9 +132,11 @@ struct nilfs_sc_info {
 
 	struct list_head	sc_dirty_files;
 	struct list_head	sc_gc_inodes;
-	struct list_head	sc_cleaning_segments;
 	struct list_head	sc_copied_buffers;
 
+	__u64		       *sc_freesegs;
+	size_t			sc_nfreesegs;
+
 	struct nilfs_inode_info *sc_dsync_inode;
 	loff_t			sc_dsync_start;
 	loff_t			sc_dsync_end;
@@ -225,10 +228,6 @@ extern void nilfs_flush_segment(struct super_block *, ino_t);
 extern int nilfs_clean_segments(struct super_block *, struct nilfs_argv *,
 				void **);
 
-extern int nilfs_segctor_add_segments_to_be_freed(struct nilfs_sc_info *,
-						  __u64 *, size_t);
-extern void nilfs_segctor_clear_segments_to_be_freed(struct nilfs_sc_info *);
-
 extern int nilfs_attach_segment_constructor(struct nilfs_sb_info *);
 extern void nilfs_detach_segment_constructor(struct nilfs_sb_info *);
 
@@ -240,5 +239,6 @@ extern int nilfs_search_super_root(struct the_nilfs *, struct nilfs_sb_info *,
 extern int nilfs_recover_logical_segments(struct the_nilfs *,
 					  struct nilfs_sb_info *,
 					  struct nilfs_recovery_info *);
+extern void nilfs_dispose_segment_list(struct list_head *);
 
 #endif /* _NILFS_SEGMENT_H */
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 98e6867..37994d4 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -18,6 +18,7 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  *
  * Written by Koji Sato <koji@osrg.net>.
+ * Rivised by Ryusuke Konishi <ryusuke@osrg.net>.
  */
 
 #include <linux/kernel.h>
@@ -108,6 +109,102 @@ static void nilfs_sufile_mod_counter(struct buffer_head *header_bh,
 	nilfs_mdt_mark_buffer_dirty(header_bh);
 }
 
+/**
+ * nilfs_sufile_updatev - modify multiple segment usages at a time
+ * @sufile: inode of segment usage file
+ * @segnumv: array of segment numbers
+ * @nsegs: size of @segnumv array
+ * @create: creation flag
+ * @ndone: place to store number of modified segments on @segnumv
+ * @dofunc: primitive operation for the update
+ *
+ * Description: nilfs_sufile_updatev() repeatedly calls @dofunc
+ * against the given array of segments.  The @dofunc is called with
+ * buffers of a header block and the sufile block in which the target
+ * segment usage entry is contained.  If @ndone is given, the number
+ * of successfully modified segments from the head is stored in the
+ * place @ndone points to.
+ *
+ * Return Value: On success, zero is returned.  On error, one of the
+ * following negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - Given segment usage is in hole block (may be returned if
+ *            @create is zero)
+ *
+ * %-EINVAL - Invalid segment usage number
+ */
+int nilfs_sufile_updatev(struct inode *sufile, __u64 *segnumv, size_t nsegs,
+			 int create, size_t *ndone,
+			 void (*dofunc)(struct inode *, __u64,
+					struct buffer_head *,
+					struct buffer_head *))
+{
+	struct buffer_head *header_bh, *bh;
+	unsigned long blkoff, prev_blkoff;
+	__u64 *seg;
+	size_t nerr = 0, n = 0;
+	int ret = 0;
+
+	if (unlikely(nsegs == 0))
+		goto out;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+	for (seg = segnumv; seg < segnumv + nsegs; seg++) {
+		if (unlikely(*seg >= nilfs_sufile_get_nsegments(sufile))) {
+			printk(KERN_WARNING
+			       "%s: invalid segment number: %llu\n", __func__,
+			       (unsigned long long)*seg);
+			nerr++;
+		}
+	}
+	if (nerr > 0) {
+		ret = -EINVAL;
+		goto out_sem;
+	}
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out_sem;
+
+	seg = segnumv;
+	blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
+	ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
+	if (ret < 0)
+		goto out_header;
+
+	for (;;) {
+		dofunc(sufile, *seg, header_bh, bh);
+
+		if (++seg >= segnumv + nsegs)
+			break;
+		prev_blkoff = blkoff;
+		blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
+		if (blkoff == prev_blkoff)
+			continue;
+
+		/* get different block */
+		brelse(bh);
+		ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
+		if (unlikely(ret < 0))
+			goto out_header;
+	}
+	brelse(bh);
+
+ out_header:
+	n = seg - segnumv;
+	brelse(header_bh);
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+ out:
+	if (ndone)
+		*ndone = n;
+	return ret;
+}
+
 int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
 			void (*dofunc)(struct inode *, __u64,
 				       struct buffer_head *,
@@ -490,7 +587,8 @@ void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
  * nilfs_sufile_get_suinfo -
  * @sufile: inode of segment usage file
  * @segnum: segment number to start looking
- * @si: array of suinfo
+ * @buf: array of suinfo
+ * @sisz: byte size of suinfo
  * @nsi: size of suinfo array
  *
  * Description:
@@ -502,11 +600,12 @@ void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
  *
  * %-ENOMEM - Insufficient amount of memory available.
  */
-ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
-				struct nilfs_suinfo *si, size_t nsi)
+ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
+				unsigned sisz, size_t nsi)
 {
 	struct buffer_head *su_bh;
 	struct nilfs_segment_usage *su;
+	struct nilfs_suinfo *si = buf;
 	size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 	struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
 	void *kaddr;
@@ -531,20 +630,22 @@ ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
 			if (ret != -ENOENT)
 				goto out;
 			/* hole */
-			memset(&si[i], 0, sizeof(struct nilfs_suinfo) * n);
+			memset(si, 0, sisz * n);
+			si = (void *)si + sisz * n;
 			continue;
 		}
 
 		kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 		su = nilfs_sufile_block_get_segment_usage(
 			sufile, segnum, su_bh, kaddr);
-		for (j = 0; j < n; j++, su = (void *)su + susz) {
-			si[i + j].sui_lastmod = le64_to_cpu(su->su_lastmod);
-			si[i + j].sui_nblocks = le32_to_cpu(su->su_nblocks);
-			si[i + j].sui_flags = le32_to_cpu(su->su_flags) &
+		for (j = 0; j < n;
+		     j++, su = (void *)su + susz, si = (void *)si + sisz) {
+			si->sui_lastmod = le64_to_cpu(su->su_lastmod);
+			si->sui_nblocks = le32_to_cpu(su->su_nblocks);
+			si->sui_flags = le32_to_cpu(su->su_flags) &
 				~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 			if (nilfs_segment_is_active(nilfs, segnum + j))
-				si[i + j].sui_flags |=
+				si->sui_flags |=
 					(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 		}
 		kunmap_atomic(kaddr, KM_USER0);
diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
index a2e2efd..a2c4d76 100644
--- a/fs/nilfs2/sufile.h
+++ b/fs/nilfs2/sufile.h
@@ -43,43 +43,27 @@ void nilfs_sufile_put_segment_usage(struct inode *, __u64,
 				    struct buffer_head *);
 int nilfs_sufile_get_stat(struct inode *, struct nilfs_sustat *);
 int nilfs_sufile_get_ncleansegs(struct inode *, unsigned long *);
-ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, struct nilfs_suinfo *,
+ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, void *, unsigned,
 				size_t);
 
+int nilfs_sufile_updatev(struct inode *, __u64 *, size_t, int, size_t *,
+			 void (*dofunc)(struct inode *, __u64,
+					struct buffer_head *,
+					struct buffer_head *));
 int nilfs_sufile_update(struct inode *, __u64, int,
 			void (*dofunc)(struct inode *, __u64,
 				       struct buffer_head *,
 				       struct buffer_head *));
-void nilfs_sufile_do_cancel_free(struct inode *, __u64, struct buffer_head *,
-				 struct buffer_head *);
 void nilfs_sufile_do_scrap(struct inode *, __u64, struct buffer_head *,
 			   struct buffer_head *);
 void nilfs_sufile_do_free(struct inode *, __u64, struct buffer_head *,
 			  struct buffer_head *);
+void nilfs_sufile_do_cancel_free(struct inode *, __u64, struct buffer_head *,
+				 struct buffer_head *);
 void nilfs_sufile_do_set_error(struct inode *, __u64, struct buffer_head *,
 			       struct buffer_head *);
 
 /**
- * nilfs_sufile_cancel_free -
- * @sufile: inode of segment usage file
- * @segnum: segment number
- *
- * Description:
- *
- * Return Value: On success, 0 is returned. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- */
-static inline int nilfs_sufile_cancel_free(struct inode *sufile, __u64 segnum)
-{
-	return nilfs_sufile_update(sufile, segnum, 0,
-				   nilfs_sufile_do_cancel_free);
-}
-
-/**
  * nilfs_sufile_scrap - make a segment garbage
  * @sufile: inode of segment usage file
  * @segnum: segment number to be freed
@@ -100,6 +84,38 @@ static inline int nilfs_sufile_free(struct inode *sufile, __u64 segnum)
 }
 
 /**
+ * nilfs_sufile_freev - free segments
+ * @sufile: inode of segment usage file
+ * @segnumv: array of segment numbers
+ * @nsegs: size of @segnumv array
+ * @ndone: place to store the number of freed segments
+ */
+static inline int nilfs_sufile_freev(struct inode *sufile, __u64 *segnumv,
+				     size_t nsegs, size_t *ndone)
+{
+	return nilfs_sufile_updatev(sufile, segnumv, nsegs, 0, ndone,
+				    nilfs_sufile_do_free);
+}
+
+/**
+ * nilfs_sufile_cancel_freev - reallocate freeing segments
+ * @sufile: inode of segment usage file
+ * @segnumv: array of segment numbers
+ * @nsegs: size of @segnumv array
+ * @ndone: place to store the number of cancelled segments
+ *
+ * Return Value: On success, 0 is returned. On error, a negative error codes
+ * is returned.
+ */
+static inline int nilfs_sufile_cancel_freev(struct inode *sufile,
+					    __u64 *segnumv, size_t nsegs,
+					    size_t *ndone)
+{
+	return nilfs_sufile_updatev(sufile, segnumv, nsegs, 0, ndone,
+				    nilfs_sufile_do_cancel_free);
+}
+
+/**
  * nilfs_sufile_set_error - mark a segment as erroneous
  * @sufile: inode of segment usage file
  * @segnum: segment number
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 1777a34..ab785f8 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -133,7 +133,7 @@ void nilfs_warning(struct super_block *sb, const char *function,
 
 static struct kmem_cache *nilfs_inode_cachep;
 
-struct inode *nilfs_alloc_inode(struct super_block *sb)
+struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 {
 	struct nilfs_inode_info *ii;
 
@@ -143,10 +143,15 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
 	ii->i_bh = NULL;
 	ii->i_state = 0;
 	ii->vfs_inode.i_version = 1;
-	nilfs_btnode_cache_init(&ii->i_btnode_cache);
+	nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 	return &ii->vfs_inode;
 }
 
+struct inode *nilfs_alloc_inode(struct super_block *sb)
+{
+	return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
+}
+
 void nilfs_destroy_inode(struct inode *inode)
 {
 	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index e4e5c78..8b88898 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -32,7 +32,6 @@
 #include "cpfile.h"
 #include "sufile.h"
 #include "dat.h"
-#include "seglist.h"
 #include "segbuf.h"