[Ocfs2-tools-devel] [RFC 1/4] dx_dirs v1: libocfs2/dealloc.[ch]

[Tao Ma]

Hi coly,
	thanks for the work by now. Some comments below.

Coly Li wrote:
> This patch adds libocfs2/dealloc.c and libocfs2/dealloc.h for truncate log.
So why do you want to add truncate log function in libocfs2? I am afraid 
we shouldn't allow the user to have the ability to play with truncate 
log which is a system file. It is very tricky. ;)

Another point is about the place you want to use it. I see your comments 
in [RFC 0/4] that you want to use it in fsck.ocfs2. But actually 
fsck.ocfs2 already have the function to clear and flush the truncate 
log. See o2fsck_replay_truncate_logs. If it doesn't meet you need, go 
and change as you wish. :)

The 3rd point is that in the user space, if you want to free some 
clusters, just do it(ocfs2_free_clusters should work for you, no need to 
add them to truncate log I guess).

Regards,
Tao
> 
> Signed-off-by: Coly Li <coly.li at suse.de>
> ---
> diff --git a/libocfs2/dealloc.c b/libocfs2/dealloc.c
> new file mode 100644
> index 0000000..48ca70c
> --- /dev/null
> +++ b/libocfs2/dealloc.c
> @@ -0,0 +1,187 @@
> +/* -*- mode: c; c-basic-offset: 8; -*-
> + * vim: noexpandtab sw=8 ts=8 sts=0:
> + *
> + * Copyright (C) 2009 Novell.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License, version 2,  as published by the Free Software Foundation.
> + *
> + * 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., 59 Temple Place - Suite 330,
> + * Boston, MA 021110-1307, USA.
> + */
> +
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <ocfs2/ocfs2.h>
> +
> +#include "dealloc.h"
> +
> +int ocfs2_truncate_log_needs_flush(struct ocfs2_truncate_log *tl)
> +{
> +	return (tl->tl_used == tl->tl_count);
> +}
> +
> +static int ocfs2_replay_truncate_records(ocfs2_filesys *fs,
> +		struct ocfs2_dinode *bitmap_di, struct ocfs2_truncate_log *tl)
> +{
> +	struct ocfs2_truncate_rec rec;
> +	uint64_t start_blk;
> +	unsigned int num_clusters;
> +	int i, ret = 0;
> +
> +	i = tl->tl_used - 1;
> +	while (i >=0) {
> +		tl->tl_used = i;
> +		rec = tl->tl_recs[i];
> +		start_blk = ocfs2_clusters_to_blocks(fs, rec.t_start);
> +		num_clusters = rec.t_clusters;
> +
> +		if (start_blk) {
> +			ret = ocfs2_free_clusters(fs, num_clusters, start_blk);
> +			if (ret) {
> +				goto bail;
> +			}
> +		}
> +		i--;
> +	}
> +bail:
> +	return ret;
> +}
> +
> +static int __ocfs2_flush_truncate_log(ocfs2_filesys *fs,
> +		struct ocfs2_truncate_log *tl)
> +{
> +	int ret = 0;
> +	uint64_t blkno;
> +	int num_to_flush;
> +	char *buf = NULL;
> +	struct ocfs2_dinode *bitmap_di;
> +
> +	num_to_flush = tl->tl_used;
> +	if (!num_to_flush)
> +		goto bail;
> +
> +	ret = ocfs2_lookup_system_inode(fs, GLOBAL_BITMAP_SYSTEM_INODE,
> +			OCFS2_INVALID_SLOT, &blkno);
> +	if (ret)
> +		goto bail;
> +
> +	ret = ocfs2_read_inode(fs, blkno, buf);
> +	if (ret)
> +		goto bail;
> +
> +	bitmap_di = (struct ocfs2_dinode *)buf;
> +
> +	ret = ocfs2_replay_truncate_records(fs, bitmap_di, tl);
> +	if (ret < 0)
> +		goto bail;
> +
> +bail:
> +	if (buf)
> +		ocfs2_free(&buf);
> +	return ret;
> +}
> +
> +int ocfs2_flush_truncate_log(ocfs2_filesys *fs,
> +		struct ocfs2_truncate_log *tl)
> +{
> +	int ret;
> +	ret = __ocfs2_flush_truncate_log(fs, tl);
> +	return ret;
> +}
> +
> +static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
> +				unsigned int new_start)
> +{
> +	unsigned int tail_index;
> +	unsigned int current_tail;
> +
> +	if (!tl->tl_used)
> +		return 0;
> +
> +	tail_index = tl->tl_used -1;
> +	current_tail = tl->tl_recs[tail_index].t_start;
> +	current_tail += tl->tl_recs[tail_index].t_clusters;
> +
> +	return (current_tail == new_start);
> +}
> +
> +errcode_t ocfs2_truncate_log_append(ocfs2_filesys *fs,
> +				struct ocfs2_dinode *di,
> +				struct ocfs2_truncate_log *tl,
> +				uint64_t start_blk,
> +				unsigned int num_clusters)
> +{
> +	unsigned int start_cluster, tl_count;
> +	int index, ret = 0;
> +
> +	start_cluster = ocfs2_blocks_to_clusters(fs, start_blk);
> +	tl_count = tl->tl_count;
> +	if (tl_count > ocfs2_truncate_recs_per_inode(fs->fs_blocksize) || tl_count == 0) {
> +		printf("truncate log error.\n");
> +		goto out;
> +	}
> +
> +	index = tl->tl_used;
> +
> +	if (index >= tl_count) {
> +		ret = OCFS2_ET_NO_SPACE;
> +		goto out;
> +	}
> +
> +	if (ocfs2_truncate_log_can_coalesce(tl, start_cluster)) {
> +		index --;
> +		num_clusters += tl->tl_recs[index].t_clusters;
> +	} else {
> +		tl->tl_recs[index].t_start = start_cluster;
> +		tl->tl_used = index + 1;
> +	}
> +	tl->tl_recs[index].t_clusters = num_clusters;
> +out:
> +	return ret;
> +}
> +
> +int ocfs2_flush_truncate_log_all(ocfs2_filesys *fs)
> +{
> +	struct ocfs2_super_block *super;
> +	struct ocfs2_dinode *di;
> +	struct ocfs2_truncate_log *tl;
> +	int i, ret = 0;
> +	uint64_t blkno;
> +	char *buf = NULL;
> +
> +	ret = ocfs2_malloc_block(fs->fs_io, &buf);
> +	if (ret)
> +		goto out;
> +
> +	super = OCFS2_RAW_SB(fs->fs_super);
> +
> +	for (i = 0; i < super->s_max_slots; i++) {
> +		ret = ocfs2_lookup_system_inode(fs, TRUNCATE_LOG_SYSTEM_INODE,
> +				i, &blkno);
> +		if (ret)
> +			goto out;
> +		ret = ocfs2_read_inode(fs, blkno, buf);
> +		if (ret)
> +			goto out;
> +		di = (struct ocfs2_dinode *)buf;
> +		tl = &di->id2.i_dealloc;
> +		ret = ocfs2_flush_truncate_log(fs, tl);
> +		if (ret)
> +			goto out;
> +	}
> +
> +out:
> +	if (buf)
> +		ocfs2_free(&buf);
> +	return ret;
> +}
> diff --git a/libocfs2/dealloc.h b/libocfs2/dealloc.h
> new file mode 100644
> index 0000000..72303e6
> --- /dev/null
> +++ b/libocfs2/dealloc.h
> @@ -0,0 +1,22 @@
> +/* -*- mode: c; c-basic-offset: 8; -*-
> + * vim: noexpandtab sw=8 ts=8 sts=0:
> + *
> + * dealloc.h
> + *
> + * Copyright (C) 2009 Novell.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License version 2 as published by the Free Software Foundation.
> + *
> + * 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.
> + */
> +
> +int ocfs2_truncate_log_needs_flush(struct ocfs2_truncate_log *tl);
> +int ocfs2_flush_truncate_log(ocfs2_filesys *fs, struct ocfs2_truncate_log *tl);
> +errcode_t ocfs2_truncate_log_append(ocfs2_filesys *fs, struct ocfs2_dinode *di,
> +				struct ocfs2_truncate_log *tl, uint64_t start_blk,
> +				unsigned int num_clusters);
>