fs/nilfs2/direct.c - kernel/msm-4.9 - Gitiles

 /*
  * direct.c - NILFS direct block pointer.
  *
  * Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>.
  */

 #include <linux/errno.h>
 #include "nilfs.h"
 #include "page.h"
 #include "direct.h"
 #include "alloc.h"
 #include "dat.h"

 static inline __le64 *nilfs_direct_dptrs(const struct nilfs_direct *direct)
 {
 	return (__le64 *)
 		((struct nilfs_direct_node *)direct->d_bmap.b_u.u_data + 1);
 }

 static inline __u64
 nilfs_direct_get_ptr(const struct nilfs_direct *direct, __u64 key)
 {
 	return nilfs_bmap_dptr_to_ptr(*(nilfs_direct_dptrs(direct) + key));
 }

 static inline void nilfs_direct_set_ptr(struct nilfs_direct *direct,
 					__u64 key, __u64 ptr)
 {
 	*(nilfs_direct_dptrs(direct) + key) = nilfs_bmap_ptr_to_dptr(ptr);
 }

 static int nilfs_direct_lookup(const struct nilfs_bmap *bmap,
 			       __u64 key, int level, __u64 *ptrp)
 {
 	struct nilfs_direct *direct;
 	__u64 ptr;

 	direct = (struct nilfs_direct *)bmap;
 	if ((key > NILFS_DIRECT_KEY_MAX) ||
 	    (level != 1) ||	/* XXX: use macro for level 1 */
 	    ((ptr = nilfs_direct_get_ptr(direct, key)) ==
 	     NILFS_BMAP_INVALID_PTR))
 		return -ENOENT;

 	if (ptrp != NULL)
 		*ptrp = ptr;
 	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)
 {
 	__u64 ptr;

 	ptr = nilfs_bmap_find_target_seq(&direct->d_bmap, key);
 	if (ptr != NILFS_BMAP_INVALID_PTR)
 		/* sequential access */
 		return ptr;
 	else
 		/* block group */
 		return nilfs_bmap_find_target_in_group(&direct->d_bmap);
 }

 static void nilfs_direct_set_target_v(struct nilfs_direct *direct,
 				      __u64 key, __u64 ptr)
 {
 	direct->d_bmap.b_last_allocated_key = key;
 	direct->d_bmap.b_last_allocated_ptr = ptr;
 }

 static int nilfs_direct_prepare_insert(struct nilfs_direct *direct,
 				       __u64 key,
 				       union nilfs_bmap_ptr_req *req,
 				       struct nilfs_bmap_stats *stats)
 {
 	int ret;

 	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;

 	stats->bs_nblocks = 1;
 	return 0;
 }

 static void nilfs_direct_commit_insert(struct nilfs_direct *direct,
 				       union nilfs_bmap_ptr_req *req,
 				       __u64 key, __u64 ptr)
 {
 	struct buffer_head *bh;

 	/* ptr must be a pointer to a buffer head. */
 	bh = (struct buffer_head *)((unsigned long)ptr);
 	set_buffer_nilfs_volatile(bh);

 	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 (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)
 {
 	struct nilfs_direct *direct;
 	union nilfs_bmap_ptr_req req;
 	struct nilfs_bmap_stats stats;
 	int ret;

 	direct = (struct nilfs_direct *)bmap;
 	if (key > NILFS_DIRECT_KEY_MAX)
 		return -ENOENT;
 	if (nilfs_direct_get_ptr(direct, key) != NILFS_BMAP_INVALID_PTR)
 		return -EEXIST;

 	ret = nilfs_direct_prepare_insert(direct, key, &req, &stats);
 	if (ret < 0)
 		return ret;
 	nilfs_direct_commit_insert(direct, &req, key, ptr);
 	nilfs_bmap_add_blocks(bmap, stats.bs_nblocks);

 	return 0;
 }

 static int nilfs_direct_prepare_delete(struct nilfs_direct *direct,
 				       union nilfs_bmap_ptr_req *req,
 				       __u64 key,
 				       struct nilfs_bmap_stats *stats)
 {
 	int ret;

 	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)
 {
 	nilfs_bmap_commit_end_ptr(&direct->d_bmap, req);
 	nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
 }

 static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
 {
 	struct nilfs_direct *direct;
 	union nilfs_bmap_ptr_req req;
 	struct nilfs_bmap_stats stats;
 	int ret;

 	direct = (struct nilfs_direct *)bmap;
 	if ((key > NILFS_DIRECT_KEY_MAX) ||
 	    nilfs_direct_get_ptr(direct, key) == NILFS_BMAP_INVALID_PTR)
 		return -ENOENT;

 	ret = nilfs_direct_prepare_delete(direct, &req, key, &stats);
 	if (ret < 0)
 		return ret;
 	nilfs_direct_commit_delete(direct, &req, key);
 	nilfs_bmap_sub_blocks(bmap, stats.bs_nblocks);

 	return 0;
 }

 static int nilfs_direct_last_key(const struct nilfs_bmap *bmap, __u64 *keyp)
 {
 	struct nilfs_direct *direct;
 	__u64 key, lastkey;

 	direct = (struct nilfs_direct *)bmap;
 	lastkey = NILFS_DIRECT_KEY_MAX + 1;
 	for (key = NILFS_DIRECT_KEY_MIN; key <= NILFS_DIRECT_KEY_MAX; key++)
 		if (nilfs_direct_get_ptr(direct, key) !=
 		    NILFS_BMAP_INVALID_PTR)
 			lastkey = key;

 	if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
 		return -ENOENT;

 	*keyp = lastkey;

 	return 0;
 }

 static int nilfs_direct_check_insert(const struct nilfs_bmap *bmap, __u64 key)
 {
 	return key > NILFS_DIRECT_KEY_MAX;
 }

 static int nilfs_direct_gather_data(struct nilfs_bmap *bmap,
 				    __u64 *keys, __u64 *ptrs, int nitems)
 {
 	struct nilfs_direct *direct;
 	__u64 key;
 	__u64 ptr;
 	int n;

 	direct = (struct nilfs_direct *)bmap;
 	if (nitems > NILFS_DIRECT_NBLOCKS)
 		nitems = NILFS_DIRECT_NBLOCKS;
 	n = 0;
 	for (key = 0; key < nitems; key++) {
 		ptr = nilfs_direct_get_ptr(direct, key);
 		if (ptr != NILFS_BMAP_INVALID_PTR) {
 			keys[n] = key;
 			ptrs[n] = ptr;
 			n++;
 		}
 	}
 	return n;
 }

 int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
 				    __u64 key, __u64 *keys, __u64 *ptrs, int n)
 {
 	struct nilfs_direct *direct;
 	__le64 *dptrs;
 	int ret, i, j;

 	/* no need to allocate any resource for conversion */

 	/* delete */
 	ret = bmap->b_ops->bop_delete(bmap, key);
 	if (ret < 0)
 		return ret;

 	/* free resources */
 	if (bmap->b_ops->bop_clear != NULL)
 		bmap->b_ops->bop_clear(bmap);

 	/* convert */
 	direct = (struct nilfs_direct *)bmap;
 	dptrs = nilfs_direct_dptrs(direct);
 	for (i = 0, j = 0; i < NILFS_DIRECT_NBLOCKS; i++) {
 		if ((j < n) && (i == keys[j])) {
 			dptrs[i] = (i != key) ?
 				nilfs_bmap_ptr_to_dptr(ptrs[j]) :
 				NILFS_BMAP_INVALID_PTR;
 			j++;
 		} else
 			dptrs[i] = NILFS_BMAP_INVALID_PTR;
 	}

 	nilfs_direct_init(bmap);
 	return 0;
 }

 static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
 				    struct buffer_head *bh)
 {
 	union nilfs_bmap_ptr_req oldreq, newreq;
 	__u64 key;
 	__u64 ptr;
 	int ret;

 	key = nilfs_bmap_data_get_key(&direct->d_bmap, bh);
 	ptr = nilfs_direct_get_ptr(direct, key);
 	if (!buffer_nilfs_volatile(bh)) {
 		oldreq.bpr_ptr = ptr;
 		newreq.bpr_ptr = ptr;
 		ret = nilfs_bmap_prepare_update_v(&direct->d_bmap, &oldreq,
 						  &newreq);
 		if (ret < 0)
 			return ret;
 		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
 		ret = nilfs_bmap_mark_dirty(&direct->d_bmap, ptr);

 	return ret;
 }

 static int nilfs_direct_propagate(const struct nilfs_bmap *bmap,
 				  struct buffer_head *bh)
 {
 	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;

 	return NILFS_BMAP_USE_VBN(bmap) ?
 		nilfs_direct_propagate_v(direct, bh) : 0;
 }

 static int nilfs_direct_assign_v(struct nilfs_direct *direct,
 				 __u64 key, __u64 ptr,
 				 struct buffer_head **bh,
 				 sector_t blocknr,
 				 union nilfs_binfo *binfo)
 {
 	union nilfs_bmap_ptr_req req;
 	int ret;

 	req.bpr_ptr = ptr;
 	ret = nilfs_bmap_start_v(&direct->d_bmap, &req, blocknr);
 	if (unlikely(ret < 0))
 		return ret;

 	binfo->bi_v.bi_vblocknr = nilfs_bmap_ptr_to_dptr(ptr);
 	binfo->bi_v.bi_blkoff = nilfs_bmap_key_to_dkey(key);

 	return 0;
 }

 static int nilfs_direct_assign_p(struct nilfs_direct *direct,
 				 __u64 key, __u64 ptr,
 				 struct buffer_head **bh,
 				 sector_t blocknr,
 				 union nilfs_binfo *binfo)
 {
 	nilfs_direct_set_ptr(direct, key, blocknr);

 	binfo->bi_dat.bi_blkoff = nilfs_bmap_key_to_dkey(key);
 	binfo->bi_dat.bi_level = 0;

 	return 0;
 }

 static int nilfs_direct_assign(struct nilfs_bmap *bmap,
 			       struct buffer_head **bh,
 			       sector_t blocknr,
 			       union nilfs_binfo *binfo)
 {
 	struct nilfs_direct *direct;
 	__u64 key;
 	__u64 ptr;

 	direct = (struct nilfs_direct *)bmap;
 	key = nilfs_bmap_data_get_key(bmap, *bh);
 	if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
 		printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
 		       (unsigned long long)key);
 		return -EINVAL;
 	}
 	ptr = nilfs_direct_get_ptr(direct, key);
 	if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
 		printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
 		       (unsigned long long)ptr);
 		return -EINVAL;
 	}

 	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,

 	.bop_propagate		=	nilfs_direct_propagate,

 	.bop_lookup_dirty_buffers	=	NULL,

 	.bop_assign		=	nilfs_direct_assign,
 	.bop_mark		=	NULL,

 	.bop_last_key		=	nilfs_direct_last_key,
 	.bop_check_insert	=	nilfs_direct_check_insert,
 	.bop_check_delete	=	NULL,
 	.bop_gather_data	=	nilfs_direct_gather_data,
 };


 int nilfs_direct_init(struct nilfs_bmap *bmap)
 {
 	bmap->b_ops = &nilfs_direct_ops;
 	return 0;
 }
	/*
	* direct.c - NILFS direct block pointer.
	*
	* Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>.
	*/

	#include <linux/errno.h>
	#include "nilfs.h"
	#include "page.h"
	#include "direct.h"
	#include "alloc.h"
	#include "dat.h"

	static inline __le64 nilfs_direct_dptrs(const struct nilfs_direct direct)
	{
	return (__le64 *)
	((struct nilfs_direct_node *)direct->d_bmap.b_u.u_data + 1);
	}

	static inline __u64
	nilfs_direct_get_ptr(const struct nilfs_direct *direct, __u64 key)
	{
	return nilfs_bmap_dptr_to_ptr(*(nilfs_direct_dptrs(direct) + key));
	}

	static inline void nilfs_direct_set_ptr(struct nilfs_direct *direct,
	__u64 key, __u64 ptr)
	{
	*(nilfs_direct_dptrs(direct) + key) = nilfs_bmap_ptr_to_dptr(ptr);
	}

	static int nilfs_direct_lookup(const struct nilfs_bmap *bmap,
	__u64 key, int level, __u64 *ptrp)
	{
	struct nilfs_direct *direct;
	__u64 ptr;

	direct = (struct nilfs_direct *)bmap;
	if ((key > NILFS_DIRECT_KEY_MAX) \|\|
	(level != 1) \|\| /* XXX: use macro for level 1 */
	((ptr = nilfs_direct_get_ptr(direct, key)) ==
	NILFS_BMAP_INVALID_PTR))
	return -ENOENT;

	if (ptrp != NULL)
	*ptrp = ptr;
	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)
	{
	__u64 ptr;

	ptr = nilfs_bmap_find_target_seq(&direct->d_bmap, key);
	if (ptr != NILFS_BMAP_INVALID_PTR)
	/* sequential access */
	return ptr;
	else
	/* block group */
	return nilfs_bmap_find_target_in_group(&direct->d_bmap);
	}

	static void nilfs_direct_set_target_v(struct nilfs_direct *direct,
	__u64 key, __u64 ptr)
	{
	direct->d_bmap.b_last_allocated_key = key;
	direct->d_bmap.b_last_allocated_ptr = ptr;
	}

	static int nilfs_direct_prepare_insert(struct nilfs_direct *direct,
	__u64 key,
	union nilfs_bmap_ptr_req *req,
	struct nilfs_bmap_stats *stats)
	{
	int ret;

	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;

	stats->bs_nblocks = 1;
	return 0;
	}

	static void nilfs_direct_commit_insert(struct nilfs_direct *direct,
	union nilfs_bmap_ptr_req *req,
	__u64 key, __u64 ptr)
	{
	struct buffer_head *bh;

	/* ptr must be a pointer to a buffer head. */
	bh = (struct buffer_head *)((unsigned long)ptr);
	set_buffer_nilfs_volatile(bh);

	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 (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)
	{
	struct nilfs_direct *direct;
	union nilfs_bmap_ptr_req req;
	struct nilfs_bmap_stats stats;
	int ret;

	direct = (struct nilfs_direct *)bmap;
	if (key > NILFS_DIRECT_KEY_MAX)
	return -ENOENT;
	if (nilfs_direct_get_ptr(direct, key) != NILFS_BMAP_INVALID_PTR)
	return -EEXIST;

	ret = nilfs_direct_prepare_insert(direct, key, &req, &stats);
	if (ret < 0)
	return ret;
	nilfs_direct_commit_insert(direct, &req, key, ptr);
	nilfs_bmap_add_blocks(bmap, stats.bs_nblocks);

	return 0;
	}

	static int nilfs_direct_prepare_delete(struct nilfs_direct *direct,
	union nilfs_bmap_ptr_req *req,
	__u64 key,
	struct nilfs_bmap_stats *stats)
	{
	int ret;

	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)
	{
	nilfs_bmap_commit_end_ptr(&direct->d_bmap, req);
	nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
	}

	static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
	{
	struct nilfs_direct *direct;
	union nilfs_bmap_ptr_req req;
	struct nilfs_bmap_stats stats;
	int ret;

	direct = (struct nilfs_direct *)bmap;
	if ((key > NILFS_DIRECT_KEY_MAX) \|\|
	nilfs_direct_get_ptr(direct, key) == NILFS_BMAP_INVALID_PTR)
	return -ENOENT;

	ret = nilfs_direct_prepare_delete(direct, &req, key, &stats);
	if (ret < 0)
	return ret;
	nilfs_direct_commit_delete(direct, &req, key);
	nilfs_bmap_sub_blocks(bmap, stats.bs_nblocks);

	return 0;
	}

	static int nilfs_direct_last_key(const struct nilfs_bmap bmap, __u64 keyp)
	{
	struct nilfs_direct *direct;
	__u64 key, lastkey;

	direct = (struct nilfs_direct *)bmap;
	lastkey = NILFS_DIRECT_KEY_MAX + 1;
	for (key = NILFS_DIRECT_KEY_MIN; key <= NILFS_DIRECT_KEY_MAX; key++)
	if (nilfs_direct_get_ptr(direct, key) !=
	NILFS_BMAP_INVALID_PTR)
	lastkey = key;

	if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
	return -ENOENT;

	*keyp = lastkey;

	return 0;
	}

	static int nilfs_direct_check_insert(const struct nilfs_bmap *bmap, __u64 key)
	{
	return key > NILFS_DIRECT_KEY_MAX;
	}

	static int nilfs_direct_gather_data(struct nilfs_bmap *bmap,
	__u64 keys, __u64 ptrs, int nitems)
	{
	struct nilfs_direct *direct;
	__u64 key;
	__u64 ptr;
	int n;

	direct = (struct nilfs_direct *)bmap;
	if (nitems > NILFS_DIRECT_NBLOCKS)
	nitems = NILFS_DIRECT_NBLOCKS;
	n = 0;
	for (key = 0; key < nitems; key++) {
	ptr = nilfs_direct_get_ptr(direct, key);
	if (ptr != NILFS_BMAP_INVALID_PTR) {
	keys[n] = key;
	ptrs[n] = ptr;
	n++;
	}
	}
	return n;
	}

	int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
	__u64 key, __u64 keys, __u64 ptrs, int n)
	{
	struct nilfs_direct *direct;
	__le64 *dptrs;
	int ret, i, j;

	/* no need to allocate any resource for conversion */

	/* delete */
	ret = bmap->b_ops->bop_delete(bmap, key);
	if (ret < 0)
	return ret;

	/* free resources */
	if (bmap->b_ops->bop_clear != NULL)
	bmap->b_ops->bop_clear(bmap);

	/* convert */
	direct = (struct nilfs_direct *)bmap;
	dptrs = nilfs_direct_dptrs(direct);
	for (i = 0, j = 0; i < NILFS_DIRECT_NBLOCKS; i++) {
	if ((j < n) && (i == keys[j])) {
	dptrs[i] = (i != key) ?
	nilfs_bmap_ptr_to_dptr(ptrs[j]) :
	NILFS_BMAP_INVALID_PTR;
	j++;
	} else
	dptrs[i] = NILFS_BMAP_INVALID_PTR;
	}

	nilfs_direct_init(bmap);
	return 0;
	}

	static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
	struct buffer_head *bh)
	{
	union nilfs_bmap_ptr_req oldreq, newreq;
	__u64 key;
	__u64 ptr;
	int ret;

	key = nilfs_bmap_data_get_key(&direct->d_bmap, bh);
	ptr = nilfs_direct_get_ptr(direct, key);
	if (!buffer_nilfs_volatile(bh)) {
	oldreq.bpr_ptr = ptr;
	newreq.bpr_ptr = ptr;
	ret = nilfs_bmap_prepare_update_v(&direct->d_bmap, &oldreq,
	&newreq);
	if (ret < 0)
	return ret;
	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
	ret = nilfs_bmap_mark_dirty(&direct->d_bmap, ptr);

	return ret;
	}

	static int nilfs_direct_propagate(const struct nilfs_bmap *bmap,
	struct buffer_head *bh)
	{
	struct nilfs_direct direct = (struct nilfs_direct )bmap;

	return NILFS_BMAP_USE_VBN(bmap) ?
	nilfs_direct_propagate_v(direct, bh) : 0;
	}

	static int nilfs_direct_assign_v(struct nilfs_direct *direct,
	__u64 key, __u64 ptr,
	struct buffer_head **bh,
	sector_t blocknr,
	union nilfs_binfo *binfo)
	{
	union nilfs_bmap_ptr_req req;
	int ret;

	req.bpr_ptr = ptr;
	ret = nilfs_bmap_start_v(&direct->d_bmap, &req, blocknr);
	if (unlikely(ret < 0))
	return ret;

	binfo->bi_v.bi_vblocknr = nilfs_bmap_ptr_to_dptr(ptr);
	binfo->bi_v.bi_blkoff = nilfs_bmap_key_to_dkey(key);

	return 0;
	}

	static int nilfs_direct_assign_p(struct nilfs_direct *direct,
	__u64 key, __u64 ptr,
	struct buffer_head **bh,
	sector_t blocknr,
	union nilfs_binfo *binfo)
	{
	nilfs_direct_set_ptr(direct, key, blocknr);

	binfo->bi_dat.bi_blkoff = nilfs_bmap_key_to_dkey(key);
	binfo->bi_dat.bi_level = 0;

	return 0;
	}

	static int nilfs_direct_assign(struct nilfs_bmap *bmap,
	struct buffer_head **bh,
	sector_t blocknr,
	union nilfs_binfo *binfo)
	{
	struct nilfs_direct *direct;
	__u64 key;
	__u64 ptr;

	direct = (struct nilfs_direct *)bmap;
	key = nilfs_bmap_data_get_key(bmap, *bh);
	if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
	printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
	(unsigned long long)key);
	return -EINVAL;
	}
	ptr = nilfs_direct_get_ptr(direct, key);
	if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
	printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
	(unsigned long long)ptr);
	return -EINVAL;
	}

	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,

	.bop_propagate = nilfs_direct_propagate,

	.bop_lookup_dirty_buffers = NULL,

	.bop_assign = nilfs_direct_assign,
	.bop_mark = NULL,

	.bop_last_key = nilfs_direct_last_key,
	.bop_check_insert = nilfs_direct_check_insert,
	.bop_check_delete = NULL,
	.bop_gather_data = nilfs_direct_gather_data,
	};


	int nilfs_direct_init(struct nilfs_bmap *bmap)
	{
	bmap->b_ops = &nilfs_direct_ops;
	return 0;
	}