/*
* 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"
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) | (1 << BIO_RW_UNPLUG);
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;
}
