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
  ...

26 files changed, 725 insertions, 858 deletions

diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
index 064279e33bbb..36df60b6d8a4 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 4f2708abb1ba..b2890cdcef12 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 4cc07b2c30e0..7e0b61be212e 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 35faa86444a7..3e2275172ed6 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 6b37a2767293..aa412724b64e 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);