[linux-2.6-block.git] / fs / nilfs2 / segbuf.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.
 *
 * Written by Ryusuke Konishi.
 *
 */

#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/crc32.h>
#include <linux/backing-dev.h>
#include <linux/slab.h>
#include "page.h"
#include "segbuf.h"


struct nilfs_write_info {
	struct the_nilfs       *nilfs;
	struct bio	       *bio;
	int			start, end; /* The region to be submitted */
	int			rest_blocks;
	int			max_pages;
	int			nr_vecs;
	sector_t		blocknr;
};

static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
			      struct the_nilfs *nilfs);
static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);

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_super_root = NULL;

	init_completion(&segbuf->sb_bio_event);
	atomic_set(&segbuf->sb_err, 0);
	segbuf->sb_nbio = 0;

	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;
}

/**
 * nilfs_segbuf_map_cont - map a new log behind a given log
 * @segbuf: new segment buffer
 * @prev: segment buffer containing a log to be continued
 */
void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
			   struct nilfs_segment_buffer *prev)
{
	segbuf->sb_segnum = prev->sb_segnum;
	segbuf->sb_fseg_start = prev->sb_fseg_start;
	segbuf->sb_fseg_end = prev->sb_fseg_end;
	segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
	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 int flags,
		       time_t ctime, __u64 cno)
{
	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_sum.cno = cno;
	return 0;
}

/*
 * Setup segment 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;
	raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
}

/*
 * CRC calculation routines
 */
static 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);
}

static 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);
		crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
		kunmap_atomic(kaddr);
	}
	raw_sum->ss_datasum = cpu_to_le32(crc);
}

static void
nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
				    u32 seed)
{
	struct nilfs_super_root *raw_sr;
	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
	unsigned int srsize;
	u32 crc;

	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
	crc = crc32_le(seed,
		       (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
		       srsize - sizeof(raw_sr->sr_sum));
	raw_sr->sr_sum = cpu_to_le32(crc);
}

static 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);
		brelse(bh);
	}
}

static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
{
	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
	nilfs_release_buffers(&segbuf->sb_payload_buffers);
	segbuf->sb_super_root = NULL;
}

/*
 * Iterators for segment buffers
 */
void nilfs_clear_logs(struct list_head *logs)
{
	struct nilfs_segment_buffer *segbuf;

	list_for_each_entry(segbuf, logs, sb_list)
		nilfs_segbuf_clear(segbuf);
}

void nilfs_truncate_logs(struct list_head *logs,
			 struct nilfs_segment_buffer *last)
{
	struct nilfs_segment_buffer *n, *segbuf;

	segbuf = list_prepare_entry(last, logs, sb_list);
	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
		list_del_init(&segbuf->sb_list);
		nilfs_segbuf_clear(segbuf);
		nilfs_segbuf_free(segbuf);
	}
}

int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
{
	struct nilfs_segment_buffer *segbuf;
	int ret = 0;

	list_for_each_entry(segbuf, logs, sb_list) {
		ret = nilfs_segbuf_write(segbuf, nilfs);
		if (ret)
			break;
	}
	return ret;
}

int nilfs_wait_on_logs(struct list_head *logs)
{
	struct nilfs_segment_buffer *segbuf;
	int err, ret = 0;

	list_for_each_entry(segbuf, logs, sb_list) {
		err = nilfs_segbuf_wait(segbuf);
		if (err && !ret)
			ret = err;
	}
	return ret;
}

/**
 * nilfs_add_checksums_on_logs - add checksums on the logs
 * @logs: list of segment buffers storing target logs
 * @seed: checksum seed value
 */
void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
{
	struct nilfs_segment_buffer *segbuf;

	list_for_each_entry(segbuf, logs, sb_list) {
		if (segbuf->sb_super_root)
			nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
		nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
		nilfs_segbuf_fill_in_data_crc(segbuf, seed);
	}
}

/*
 * BIO operations
 */
static void nilfs_end_bio_write(struct bio *bio)
{
	struct nilfs_segment_buffer *segbuf = bio->bi_private;

	if (bio->bi_error)
		atomic_inc(&segbuf->sb_err);

	bio_put(bio);
	complete(&segbuf->sb_bio_event);
}

static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
				   struct nilfs_write_info *wi, int mode)
{
	struct bio *bio = wi->bio;
	int err;

	if (segbuf->sb_nbio > 0 &&
	    bdi_write_congested(segbuf->sb_super->s_bdi)) {
		wait_for_completion(&segbuf->sb_bio_event);
		segbuf->sb_nbio--;
		if (unlikely(atomic_read(&segbuf->sb_err))) {
			bio_put(bio);
			err = -EIO;
			goto failed;
		}
	}

	bio->bi_end_io = nilfs_end_bio_write;
	bio->bi_private = segbuf;
	submit_bio(mode, bio);
	segbuf->sb_nbio++;

	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 new bio for writing log
 * @nilfs: nilfs object
 * @start: start block number of the bio
 * @nr_vecs: request size of page vector.
 *
 * Return Value: On success, pointer to the struct bio is returned.
 * On error, NULL is returned.
 */
static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
				       int nr_vecs)
{
	struct bio *bio;

	bio = bio_alloc(GFP_NOIO, nr_vecs);
	if (bio == NULL) {
		while (!bio && (nr_vecs >>= 1))
			bio = bio_alloc(GFP_NOIO, nr_vecs);
	}
	if (likely(bio)) {
		bio->bi_bdev = nilfs->ns_bdev;
		bio->bi_iter.bi_sector =
			start << (nilfs->ns_blocksize_bits - 9);
	}
	return bio;
}

static 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_MAX_PAGES;
	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
	wi->start = wi->end = 0;
	wi->blocknr = segbuf->sb_pseg_start;
}

static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
				  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->nilfs, 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_segbuf_submit_bio(segbuf, wi, mode);
	/* never submit current bh */
	if (likely(!err))
		goto repeat;
	return err;
}

/**
 * nilfs_segbuf_write - submit write requests of a log
 * @segbuf: buffer storing a log to be written
 * @nilfs: nilfs object
 *
 * Return Value: On Success, 0 is returned. On Error, one of the following
 * negative error code is returned.
 *
 * %-EIO - I/O error
 *
 * %-ENOMEM - Insufficient memory available.
 */
static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
			      struct the_nilfs *nilfs)
{
	struct nilfs_write_info wi;
	struct buffer_head *bh;
	int res = 0, rw = WRITE;

	wi.nilfs = nilfs;
	nilfs_segbuf_prepare_write(segbuf, &wi);

	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
		if (unlikely(res))
			goto failed_bio;
	}

	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
		if (unlikely(res))
			goto failed_bio;
	}

	if (wi.bio) {
		/*
		 * Last BIO is always sent through the following
		 * submission.
		 */
		rw |= REQ_SYNC;
		res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
	}

 failed_bio:
	return res;
}

/**
 * nilfs_segbuf_wait - wait for completion of requested BIOs
 * @segbuf: segment buffer
 *
 * Return Value: On Success, 0 is returned. On Error, one of the following
 * negative error code is returned.
 *
 * %-EIO - I/O error
 */
static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
{
	int err = 0;

	if (!segbuf->sb_nbio)
		return 0;

	do {
		wait_for_completion(&segbuf->sb_bio_event);
	} while (--segbuf->sb_nbio > 0);

	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
		printk(KERN_ERR "NILFS: IO error writing segment\n");
		err = -EIO;
	}
	return err;
}
Commit	Line	Data
64b5a32e RK	1	/*
	2	* segbuf.c - NILFS segment buffer
	3	*
	4	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
4b420ab4	16	* Written by Ryusuke Konishi.
64b5a32e RK	17	*
	18	*/
	19
	20	#include <linux/buffer_head.h>
	21	#include <linux/writeback.h>
	22	#include <linux/crc32.h>
9c965bac	23	#include <linux/backing-dev.h>
5a0e3ad6	24	#include <linux/slab.h>
64b5a32e RK	25	#include "page.h"
64b5a32e RK	26	#include "segbuf.h"
64b5a32e RK	27
64b5a32e RK	28
9c965bac RK	29	struct nilfs_write_info {
	30	struct the_nilfs *nilfs;
	31	struct bio *bio;
55480a06	32	int start, end; /* The region to be submitted */
9c965bac RK	33	int rest_blocks;
	34	int max_pages;
	35	int nr_vecs;
	36	sector_t blocknr;
	37	};
	38
d1c6b72a RK	39	static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
	40	struct the_nilfs *nilfs);
	41	static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
	42
64b5a32e RK	43	struct nilfs_segment_buffer nilfs_segbuf_new(struct super_block sb)
	44	{
	45	struct nilfs_segment_buffer *segbuf;
	46
	47	segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
	48	if (unlikely(!segbuf))
	49	return NULL;
	50
	51	segbuf->sb_super = sb;
	52	INIT_LIST_HEAD(&segbuf->sb_list);
	53	INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
	54	INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
1e2b68bf	55	segbuf->sb_super_root = NULL;
9284ad2a RK	56
	57	init_completion(&segbuf->sb_bio_event);
	58	atomic_set(&segbuf->sb_err, 0);
	59	segbuf->sb_nbio = 0;
	60
64b5a32e RK	61	return segbuf;
	62	}
	63
	64	void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
	65	{
64b5a32e RK	66	kmem_cache_free(nilfs_segbuf_cachep, segbuf);
	67	}
	68
cece5520	69	void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
64b5a32e RK	70	unsigned long offset, struct the_nilfs *nilfs)
64b5a32e RK	71	{
64b5a32e RK	72	segbuf->sb_segnum = segnum;
	73	nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
	74	&segbuf->sb_fseg_end);
	75
	76	segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
	77	segbuf->sb_rest_blocks =
	78	segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
64b5a32e RK	79	}
64b5a32e RK	80
a694291a RK	81	/**
	82	* nilfs_segbuf_map_cont - map a new log behind a given log
	83	* @segbuf: new segment buffer
	84	* @prev: segment buffer containing a log to be continued
	85	*/
	86	void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
	87	struct nilfs_segment_buffer *prev)
	88	{
	89	segbuf->sb_segnum = prev->sb_segnum;
	90	segbuf->sb_fseg_start = prev->sb_fseg_start;
	91	segbuf->sb_fseg_end = prev->sb_fseg_end;
	92	segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
	93	segbuf->sb_rest_blocks =
	94	segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
	95	}
	96
64b5a32e RK	97	void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
	98	__u64 nextnum, struct the_nilfs *nilfs)
	99	{
	100	segbuf->sb_nextnum = nextnum;
	101	segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
	102	}
	103
	104	int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
	105	{
	106	struct buffer_head *bh;
	107
	108	bh = sb_getblk(segbuf->sb_super,
	109	segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
	110	if (unlikely(!bh))
	111	return -ENOMEM;
	112
	113	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
	114	return 0;
	115	}
	116
	117	int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
	118	struct buffer_head **bhp)
	119	{
	120	struct buffer_head *bh;
	121
	122	bh = sb_getblk(segbuf->sb_super,
	123	segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
	124	if (unlikely(!bh))
	125	return -ENOMEM;
	126
	127	nilfs_segbuf_add_payload_buffer(segbuf, bh);
	128	*bhp = bh;
	129	return 0;
	130	}
	131
0c6c44cb	132	int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
50614bcf	133	time_t ctime, __u64 cno)
64b5a32e RK	134	{
	135	int err;
	136
	137	segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
	138	err = nilfs_segbuf_extend_segsum(segbuf);
	139	if (unlikely(err))
	140	return err;
	141
	142	segbuf->sb_sum.flags = flags;
	143	segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
	144	segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
	145	segbuf->sb_sum.ctime = ctime;
50614bcf	146	segbuf->sb_sum.cno = cno;
64b5a32e RK	147	return 0;
	148	}
	149
	150	/*
7a65004b	151	* Setup segment summary
64b5a32e RK	152	*/
	153	void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
	154	{
	155	struct nilfs_segment_summary *raw_sum;
	156	struct buffer_head *bh_sum;
	157
	158	bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
	159	struct buffer_head, b_assoc_buffers);
	160	raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
	161
	162	raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC);
	163	raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum));
	164	raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags);
	165	raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq);
	166	raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime);
	167	raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next);
	168	raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks);
	169	raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
	170	raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
	171	raw_sum->ss_pad = 0;
50614bcf	172	raw_sum->ss_cno = cpu_to_le64(segbuf->sb_sum.cno);
64b5a32e RK	173	}
	174
	175	/*
	176	* CRC calculation routines
	177	*/
aaed1d5b RK	178	static void
aaed1d5b RK	179	nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
64b5a32e RK	180	{
	181	struct buffer_head *bh;
	182	struct nilfs_segment_summary *raw_sum;
	183	unsigned long size, bytes = segbuf->sb_sum.sumbytes;
	184	u32 crc;
	185
	186	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
	187	b_assoc_buffers);
	188
	189	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
	190	size = min_t(unsigned long, bytes, bh->b_size);
	191	crc = crc32_le(seed,
	192	(unsigned char *)raw_sum +
	193	sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
	194	size - (sizeof(raw_sum->ss_datasum) +
	195	sizeof(raw_sum->ss_sumsum)));
	196
	197	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
	198	b_assoc_buffers) {
	199	bytes -= size;
	200	size = min_t(unsigned long, bytes, bh->b_size);
	201	crc = crc32_le(crc, bh->b_data, size);
	202	}
	203	raw_sum->ss_sumsum = cpu_to_le32(crc);
	204	}
	205
aaed1d5b RK	206	static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
aaed1d5b RK	207	u32 seed)
64b5a32e RK	208	{
	209	struct buffer_head *bh;
	210	struct nilfs_segment_summary *raw_sum;
	211	void *kaddr;
	212	u32 crc;
	213
	214	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
	215	b_assoc_buffers);
	216	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
	217	crc = crc32_le(seed,
	218	(unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
	219	bh->b_size - sizeof(raw_sum->ss_datasum));
	220
	221	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
	222	b_assoc_buffers) {
	223	crc = crc32_le(crc, bh->b_data, bh->b_size);
	224	}
	225	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
7b9c0976	226	kaddr = kmap_atomic(bh->b_page);
64b5a32e	227	crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
7b9c0976	228	kunmap_atomic(kaddr);
64b5a32e RK	229	}
	230	raw_sum->ss_datasum = cpu_to_le32(crc);
	231	}
	232
aaed1d5b RK	233	static void
	234	nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
	235	u32 seed)
	236	{
	237	struct nilfs_super_root *raw_sr;
6c6de1aa	238	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
0c6c44cb	239	unsigned int srsize;
aaed1d5b RK	240	u32 crc;
	241
	242	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
6c6de1aa	243	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
aaed1d5b RK	244	crc = crc32_le(seed,
aaed1d5b RK	245	(unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
6c6de1aa	246	srsize - sizeof(raw_sr->sr_sum));
aaed1d5b RK	247	raw_sr->sr_sum = cpu_to_le32(crc);
	248	}
	249
e29df395	250	static void nilfs_release_buffers(struct list_head *list)
64b5a32e RK	251	{
	252	struct buffer_head bh, n;
	253
	254	list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
	255	list_del_init(&bh->b_assoc_buffers);
64b5a32e RK	256	brelse(bh);
	257	}
	258	}
	259
e29df395 RK	260	static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
	261	{
	262	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
	263	nilfs_release_buffers(&segbuf->sb_payload_buffers);
1e2b68bf	264	segbuf->sb_super_root = NULL;
e29df395 RK	265	}
	266
	267	/*
	268	* Iterators for segment buffers
	269	*/
	270	void nilfs_clear_logs(struct list_head *logs)
	271	{
	272	struct nilfs_segment_buffer *segbuf;
	273
	274	list_for_each_entry(segbuf, logs, sb_list)
	275	nilfs_segbuf_clear(segbuf);
	276	}
	277
	278	void nilfs_truncate_logs(struct list_head *logs,
	279	struct nilfs_segment_buffer *last)
	280	{
	281	struct nilfs_segment_buffer n, segbuf;
	282
	283	segbuf = list_prepare_entry(last, logs, sb_list);
	284	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
	285	list_del_init(&segbuf->sb_list);
	286	nilfs_segbuf_clear(segbuf);
	287	nilfs_segbuf_free(segbuf);
	288	}
	289	}
	290
d1c6b72a RK	291	int nilfs_write_logs(struct list_head logs, struct the_nilfs nilfs)
	292	{
	293	struct nilfs_segment_buffer *segbuf;
	294	int ret = 0;
	295
	296	list_for_each_entry(segbuf, logs, sb_list) {
	297	ret = nilfs_segbuf_write(segbuf, nilfs);
	298	if (ret)
	299	break;
	300	}
	301	return ret;
	302	}
	303
e29df395 RK	304	int nilfs_wait_on_logs(struct list_head *logs)
	305	{
	306	struct nilfs_segment_buffer *segbuf;
d067633b	307	int err, ret = 0;
e29df395 RK	308
	309	list_for_each_entry(segbuf, logs, sb_list) {
	310	err = nilfs_segbuf_wait(segbuf);
d067633b RK	311	if (err && !ret)
d067633b RK	312	ret = err;
e29df395	313	}
d067633b	314	return ret;
e29df395 RK	315	}
e29df395 RK	316
aaed1d5b RK	317	/**
	318	* nilfs_add_checksums_on_logs - add checksums on the logs
	319	* @logs: list of segment buffers storing target logs
	320	* @seed: checksum seed value
	321	*/
	322	void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
	323	{
	324	struct nilfs_segment_buffer *segbuf;
	325
	326	list_for_each_entry(segbuf, logs, sb_list) {
	327	if (segbuf->sb_super_root)
	328	nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
	329	nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
	330	nilfs_segbuf_fill_in_data_crc(segbuf, seed);
	331	}
	332	}
	333
64b5a32e RK	334	/*
	335	* BIO operations
	336	*/
4246a0b6	337	static void nilfs_end_bio_write(struct bio *bio)
64b5a32e	338	{
9284ad2a	339	struct nilfs_segment_buffer *segbuf = bio->bi_private;
64b5a32e	340
4246a0b6	341	if (bio->bi_error)
9284ad2a	342	atomic_inc(&segbuf->sb_err);
64b5a32e RK	343
64b5a32e RK	344	bio_put(bio);
9284ad2a	345	complete(&segbuf->sb_bio_event);
64b5a32e RK	346	}
64b5a32e RK	347
9284ad2a RK	348	static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
9284ad2a RK	349	struct nilfs_write_info *wi, int mode)
64b5a32e RK	350	{
	351	struct bio *bio = wi->bio;
	352	int err;
	353
026a7d63 RK	354	if (segbuf->sb_nbio > 0 &&
026a7d63 RK	355	bdi_write_congested(segbuf->sb_super->s_bdi)) {
9284ad2a RK	356	wait_for_completion(&segbuf->sb_bio_event);
	357	segbuf->sb_nbio--;
	358	if (unlikely(atomic_read(&segbuf->sb_err))) {
64b5a32e RK	359	bio_put(bio);
	360	err = -EIO;
	361	goto failed;
	362	}
	363	}
	364
	365	bio->bi_end_io = nilfs_end_bio_write;
9284ad2a	366	bio->bi_private = segbuf;
64b5a32e	367	submit_bio(mode, bio);
4bf93b50	368	segbuf->sb_nbio++;
64b5a32e RK	369
	370	wi->bio = NULL;
	371	wi->rest_blocks -= wi->end - wi->start;
	372	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
	373	wi->start = wi->end;
	374	return 0;
	375
	376	failed:
	377	wi->bio = NULL;
	378	return err;
	379	}
	380
	381	/**
9c965bac RK	382	* nilfs_alloc_seg_bio - allocate a new bio for writing log
	383	* @nilfs: nilfs object
	384	* @start: start block number of the bio
64b5a32e RK	385	* @nr_vecs: request size of page vector.
64b5a32e RK	386	*
64b5a32e RK	387	* Return Value: On success, pointer to the struct bio is returned.
	388	* On error, NULL is returned.
	389	*/
9c965bac	390	static struct bio nilfs_alloc_seg_bio(struct the_nilfs nilfs, sector_t start,
64b5a32e RK	391	int nr_vecs)
	392	{
	393	struct bio *bio;
	394
c1b353f0	395	bio = bio_alloc(GFP_NOIO, nr_vecs);
64b5a32e RK	396	if (bio == NULL) {
64b5a32e RK	397	while (!bio && (nr_vecs >>= 1))
c1b353f0	398	bio = bio_alloc(GFP_NOIO, nr_vecs);
64b5a32e RK	399	}
64b5a32e RK	400	if (likely(bio)) {
9c965bac	401	bio->bi_bdev = nilfs->ns_bdev;
4f024f37 KO	402	bio->bi_iter.bi_sector =
4f024f37 KO	403	start << (nilfs->ns_blocksize_bits - 9);
64b5a32e RK	404	}
	405	return bio;
	406	}
	407
9c965bac RK	408	static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
9c965bac RK	409	struct nilfs_write_info *wi)
64b5a32e RK	410	{
	411	wi->bio = NULL;
	412	wi->rest_blocks = segbuf->sb_sum.nblocks;
b54ffb73	413	wi->max_pages = BIO_MAX_PAGES;
64b5a32e RK	414	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
64b5a32e RK	415	wi->start = wi->end = 0;
64b5a32e	416	wi->blocknr = segbuf->sb_pseg_start;
64b5a32e RK	417	}
64b5a32e RK	418
9284ad2a RK	419	static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
	420	struct nilfs_write_info *wi,
	421	struct buffer_head *bh, int mode)
64b5a32e RK	422	{
	423	int len, err;
	424
	425	BUG_ON(wi->nr_vecs <= 0);
	426	repeat:
	427	if (!wi->bio) {
9c965bac	428	wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
64b5a32e RK	429	wi->nr_vecs);
	430	if (unlikely(!wi->bio))
	431	return -ENOMEM;
	432	}
	433
	434	len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
	435	if (len == bh->b_size) {
	436	wi->end++;
	437	return 0;
	438	}
	439	/* bio is FULL */
9284ad2a	440	err = nilfs_segbuf_submit_bio(segbuf, wi, mode);
64b5a32e RK	441	/* never submit current bh */
	442	if (likely(!err))
	443	goto repeat;
	444	return err;
	445	}
	446
9c965bac RK	447	/**
	448	* nilfs_segbuf_write - submit write requests of a log
	449	* @segbuf: buffer storing a log to be written
	450	* @nilfs: nilfs object
	451	*
	452	* Return Value: On Success, 0 is returned. On Error, one of the following
	453	* negative error code is returned.
	454	*
	455	* %-EIO - I/O error
	456	*
	457	* %-ENOMEM - Insufficient memory available.
	458	*/
6c477d44 RK	459	static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
6c477d44 RK	460	struct the_nilfs *nilfs)
64b5a32e	461	{
9c965bac	462	struct nilfs_write_info wi;
64b5a32e	463	struct buffer_head *bh;
5f1586d0	464	int res = 0, rw = WRITE;
64b5a32e	465
9c965bac RK	466	wi.nilfs = nilfs;
	467	nilfs_segbuf_prepare_write(segbuf, &wi);
	468
64b5a32e	469	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
9c965bac	470	res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
64b5a32e RK	471	if (unlikely(res))
	472	goto failed_bio;
	473	}
	474
	475	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
9c965bac	476	res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
64b5a32e RK	477	if (unlikely(res))
	478	goto failed_bio;
	479	}
	480
9c965bac	481	if (wi.bio) {
64b5a32e RK	482	/*
	483	* Last BIO is always sent through the following
	484	* submission.
	485	*/
721a9602	486	rw \|= REQ_SYNC;
9c965bac	487	res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
64b5a32e RK	488	}
64b5a32e RK	489
64b5a32e	490	failed_bio:
5f1586d0	491	return res;
64b5a32e RK	492	}
	493
	494	/**
	495	* nilfs_segbuf_wait - wait for completion of requested BIOs
9284ad2a	496	* @segbuf: segment buffer
64b5a32e RK	497	*
	498	* Return Value: On Success, 0 is returned. On Error, one of the following
	499	* negative error code is returned.
	500	*
	501	* %-EIO - I/O error
	502	*/
6c477d44	503	static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
64b5a32e RK	504	{
	505	int err = 0;
	506
9284ad2a	507	if (!segbuf->sb_nbio)
64b5a32e RK	508	return 0;
	509
	510	do {
9284ad2a RK	511	wait_for_completion(&segbuf->sb_bio_event);
9284ad2a RK	512	} while (--segbuf->sb_nbio > 0);
64b5a32e	513
9284ad2a	514	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
64b5a32e RK	515	printk(KERN_ERR "NILFS: IO error writing segment\n");
64b5a32e RK	516	err = -EIO;
64b5a32e RK	517	}
	518	return err;
	519	}