nilfs2: direct block mapping

/*

 * 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"

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 __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 (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 (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);

	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_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);

}

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;

	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;

}

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_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;

	BUG_ON(keyp == NULL);

	*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, __u64 low, __u64 high)

{

	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, low, high);

	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(&direct->d_bmap, &oldreq,

						&newreq);

		if (ret < 0)

			return ret;

		nilfs_bmap_commit_update(&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;

	direct = (struct nilfs_direct *)bmap;

	return (direct->d_ops->dop_propagate != NULL) ?

		(*direct->d_ops->dop_propagate)(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 = (*direct->d_bmap.b_pops->bpop_prepare_start_ptr)(

		&direct->d_bmap, &req);

	if (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);

	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);

	BUG_ON(key > NILFS_DIRECT_KEY_MAX);

	ptr = nilfs_direct_get_ptr(direct, key);

	BUG_ON(ptr == NILFS_BMAP_INVALID_PTR);

	return (*direct->d_ops->dop_assign)(direct, key, ptr, bh,

					    blocknr, binfo);

}

static const struct nilfs_bmap_operations nilfs_direct_ops = {

	.bop_lookup		=	nilfs_direct_lookup,

	.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,

};

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)

{

	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;

}

/*

 * direct.h - 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>.

 */

#ifndef _NILFS_DIRECT_H

#define _NILFS_DIRECT_H

#include <linux/types.h>

#include <linux/buffer_head.h>

#include "bmap.h"

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

 */

struct nilfs_direct_node {

	__u8 dn_flags;

	__u8 pad[7];

};

/**

 * 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;

};

#define NILFS_DIRECT_NBLOCKS	(NILFS_BMAP_SIZE / sizeof(__le64) - 1)

#define NILFS_DIRECT_KEY_MIN	0

#define NILFS_DIRECT_KEY_MAX	(NILFS_DIRECT_NBLOCKS - 1)

int nilfs_direct_init(struct nilfs_bmap *, __u64, __u64);

int nilfs_direct_delete_and_convert(struct nilfs_bmap *, __u64, __u64 *,

				    __u64 *, int, __u64, __u64);

#endif	/* _NILFS_DIRECT_H */