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|
/*
* segbuf.c - NILFS segment buffer
*
* 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>
*
*/
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/crc32.h>
#include "page.h"
#include "segbuf.h"
#include "seglist.h"
static struct kmem_cache *nilfs_segbuf_cachep;
static void nilfs_segbuf_init_once(void *obj)
{
memset(obj, 0, sizeof(struct nilfs_segment_buffer));
}
int __init nilfs_init_segbuf_cache(void)
{
nilfs_segbuf_cachep =
kmem_cache_create("nilfs2_segbuf_cache",
sizeof(struct nilfs_segment_buffer),
0, SLAB_RECLAIM_ACCOUNT,
nilfs_segbuf_init_once);
return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
}
void nilfs_destroy_segbuf_cache(void)
{
kmem_cache_destroy(nilfs_segbuf_cachep);
}
struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
{
struct nilfs_segment_buffer *segbuf;
segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
if (unlikely(!segbuf))
return NULL;
segbuf->sb_super = sb;
INIT_LIST_HEAD(&segbuf->sb_list);
INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
segbuf->sb_segent = NULL;
return segbuf;
}
void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
{
struct nilfs_segment_entry *ent = segbuf->sb_segent;
if (ent != NULL && list_empty(&ent->list)) {
/* free isolated segment list head */
nilfs_free_segment_entry(segbuf->sb_segent);
segbuf->sb_segent = NULL;
}
kmem_cache_free(nilfs_segbuf_cachep, segbuf);
}
int nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
unsigned long offset, struct the_nilfs *nilfs)
{
struct nilfs_segment_entry *ent;
segbuf->sb_segnum = segnum;
nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
&segbuf->sb_fseg_end);
segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
segbuf->sb_rest_blocks =
segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
/* Attach a segment list head */
ent = segbuf->sb_segent;
if (ent == NULL) {
segbuf->sb_segent = nilfs_alloc_segment_entry(segnum);
if (unlikely(!segbuf->sb_segent))
return -ENOMEM;
} else {
BUG_ON(ent->bh_su || !list_empty(&ent->list));
ent->segnum = segnum;
}
return 0;
}
void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
__u64 nextnum, struct the_nilfs *nilfs)
{
segbuf->sb_nextnum = nextnum;
segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
}
int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
{
struct buffer_head *bh;
bh = sb_getblk(segbuf->sb_super,
segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
if (unlikely(!bh))
return -ENOMEM;
nilfs_segbuf_add_segsum_buffer(segbuf, bh);
return 0;
}
int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
struct buffer_head **bhp)
{
struct buffer_head *bh;
bh = sb_getblk(segbuf->sb_super,
segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
if (unlikely(!bh))
return -ENOMEM;
nilfs_segbuf_add_payload_buffer(segbuf, bh);
*bhp = bh;
return 0;
}
int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
time_t ctime)
{
int err;
segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
err = nilfs_segbuf_extend_segsum(segbuf);
if (unlikely(err))
return err;
segbuf->sb_sum.flags = flags;
segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
segbuf->sb_sum.ctime = ctime;
segbuf->sb_io_error = 0;
return 0;
}
/*
* Setup segument summary
*/
void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
{
struct nilfs_segment_summary *raw_sum;
struct buffer_head *bh_sum;
bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
struct buffer_head, b_assoc_buffers);
raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC);
raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum));
raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags);
raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq);
raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime);
raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next);
raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks);
raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
raw_sum->ss_pad = 0;
}
/*
* CRC calculation routines
*/
void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
u32 seed)
{
struct buffer_head *bh;
struct nilfs_segment_summary *raw_sum;
unsigned long size, bytes = segbuf->sb_sum.sumbytes;
u32 crc;
bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
b_assoc_buffers);
raw_sum = (struct nilfs_segment_summary *)bh->b_data;
size = min_t(unsigned long, bytes, bh->b_size);
crc = crc32_le(seed,
(unsigned char *)raw_sum +
sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
size - (sizeof(raw_sum->ss_datasum) +
sizeof(raw_sum->ss_sumsum)));
list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
b_assoc_buffers) {
bytes -= size;
size = min_t(unsigned long, bytes, bh->b_size);
crc = crc32_le(crc, bh->b_data, size);
}
raw_sum->ss_sumsum = cpu_to_le32(crc);
}
void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
u32 seed)
{
struct buffer_head *bh;
struct nilfs_segment_summary *raw_sum;
void *kaddr;
u32 crc;
bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
b_assoc_buffers);
raw_sum = (struct nilfs_segment_summary *)bh->b_data;
crc = crc32_le(seed,
(unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
bh->b_size - sizeof(raw_sum->ss_datasum));
list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
b_assoc_buffers) {
crc = crc32_le(crc, bh->b_data, bh->b_size);
}
list_for_each_entry(bh, &segbuf->sb_payload_buffers,<
|