linux/fs/nilfs2/segbuf.c
Ryusuke Konishi cece552074 nilfs2: simplify handling of active state of segments
will reduce some lines of segment constructor.  Previously, the state was
complexly controlled through a list of segments in order to keep
consistency in meta data of usage state of segments.  Instead, this
presents ``calculated'' active flags to userland cleaner program and stop
maintaining its real flag on disk.

Only by this fake flag, the cleaner cannot exactly know if each segment is
reclaimable or not.  However, the recent extension of nilfs_sustat ioctl
struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the
cleaner from reclaiming in-use segment wrongly.

So, now I can apply this for simplification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00

439 lines
11 KiB
C

/*
* 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);
return segbuf;
}
void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
{
kmem_cache_free(nilfs_segbuf_cachep, segbuf);
}
void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
unsigned long offset, struct the_nilfs *nilfs)
{
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;
}
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, b_assoc_buffers) {
kaddr = kmap_atomic(bh->b_page, KM_USER0);
crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
kunmap_atomic(kaddr, KM_USER0);
}
raw_sum->ss_datasum = cpu_to_le32(crc);
}
void nilfs_release_buffers(struct list_head *list)
{
struct buffer_head *bh, *n;
list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
list_del_init(&bh->b_assoc_buffers);
if (buffer_nilfs_allocated(bh)) {
struct page *clone_page = bh->b_page;
/* remove clone page */
brelse(bh);
page_cache_release(clone_page); /* for each bh */
if (page_count(clone_page) <= 2) {
lock_page(clone_page);
nilfs_free_private_page(clone_page);
}
continue;
}
brelse(bh);
}
}
/*
* BIO operations
*/
static void nilfs_end_bio_write(struct bio *bio, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct nilfs_write_info *wi = bio->bi_private;
if (err == -EOPNOTSUPP) {
set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
bio_put(bio);
/* to be detected by submit_seg_bio() */
}
if (!uptodate)
atomic_inc(&wi->err);
bio_put(bio);
complete(&wi->bio_event);
}
static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode)
{
struct bio *bio = wi->bio;
int err;
if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) {
wait_for_completion(&wi->bio_event);
wi->nbio--;
if (unlikely(atomic_read(&wi->err))) {
bio_put(bio);
err = -EIO;
goto failed;
}
}
bio->bi_end_io = nilfs_end_bio_write;
bio->bi_private = wi;
bio_get(bio);
submit_bio(mode, bio);
if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
bio_put(bio);
err = -EOPNOTSUPP;
goto failed;
}
wi->nbio++;
bio_put(bio);
wi->bio = NULL;
wi->rest_blocks -= wi->end - wi->start;
wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
wi->start = wi->end;
return 0;
failed:
wi->bio = NULL;
return err;
}
/**
* nilfs_alloc_seg_bio - allocate a bio for writing segment.
* @sb: super block
* @start: beginning disk block number of this BIO.
* @nr_vecs: request size of page vector.
*
* alloc_seg_bio() allocates a new BIO structure and initialize it.
*
* Return Value: On success, pointer to the struct bio is returned.
* On error, NULL is returned.
*/
static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
int nr_vecs)
{
struct bio *bio;
bio = bio_alloc(GFP_NOWAIT, nr_vecs);
if (bio == NULL) {
while (!bio && (nr_vecs >>= 1))
bio = bio_alloc(GFP_NOWAIT, nr_vecs);
}
if (likely(bio)) {
bio->bi_bdev = sb->s_bdev;
bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9);
}
return bio;
}
void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
struct nilfs_write_info *wi)
{
wi->bio = NULL;
wi->rest_blocks = segbuf->sb_sum.nblocks;
wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev);
wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
wi->start = wi->end = 0;
wi->nbio = 0;
wi->blocknr = segbuf->sb_pseg_start;
atomic_set(&wi->err, 0);
init_completion(&wi->bio_event);
}
static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh,
int mode)
{
int len, err;
BUG_ON(wi->nr_vecs <= 0);
repeat:
if (!wi->bio) {
wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end,
wi->nr_vecs);
if (unlikely(!wi->bio))
return -ENOMEM;
}
len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
if (len == bh->b_size) {
wi->end++;
return 0;
}
/* bio is FULL */
err = nilfs_submit_seg_bio(wi, mode);
/* never submit current bh */
if (likely(!err))
goto repeat;
return err;
}
int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
struct nilfs_write_info *wi)
{
struct buffer_head *bh;
int res, rw = WRITE;
list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
res = nilfs_submit_bh(wi, bh, rw);
if (unlikely(res))
goto failed_bio;
}
list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
res = nilfs_submit_bh(wi, bh, rw);
if (unlikely(res))
goto failed_bio;
}
if (wi->bio) {
/*
* Last BIO is always sent through the following
* submission.
*/
rw |= (1 << BIO_RW_SYNCIO);
res = nilfs_submit_seg_bio(wi, rw);
if (unlikely(res))
goto failed_bio;
}
res = 0;
out:
return res;
failed_bio:
atomic_inc(&wi->err);
goto out;
}
/**
* nilfs_segbuf_wait - wait for completion of requested BIOs
* @wi: nilfs_write_info
*
* Return Value: On Success, 0 is returned. On Error, one of the following
* negative error code is returned.
*
* %-EIO - I/O error
*/
int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf,
struct nilfs_write_info *wi)
{
int err = 0;
if (!wi->nbio)
return 0;
do {
wait_for_completion(&wi->bio_event);
} while (--wi->nbio > 0);
if (unlikely(atomic_read(&wi->err) > 0)) {
printk(KERN_ERR "NILFS: IO error writing segment\n");
err = -EIO;
segbuf->sb_io_error = 1;
}
return err;
}