[linux.git] / fs / nilfs2 / segbuf.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * segbuf.c - NILFS segment buffer
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * 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,
		       time64_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_status)
		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,
				   int mode_flags)
{
	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;
	bio_set_op_attrs(bio, mode, mode_flags);
	submit_bio(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_set_dev(bio, 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, 0);
	/* 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;

	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, REQ_OP_WRITE);
		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, REQ_OP_WRITE);
		if (unlikely(res))
			goto failed_bio;
	}

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

 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)) {
		nilfs_err(segbuf->sb_super,
			  "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
			  (unsigned long long)segbuf->sb_pseg_start,
			  segbuf->sb_sum.nblocks,
			  (unsigned long long)segbuf->sb_segnum);
		err = -EIO;
	}
	return err;
}
Commit	Line	Data
ae98043f	1	// SPDX-License-Identifier: GPL-2.0+
64b5a32e RK	2	/*
	3	* segbuf.c - NILFS segment buffer
	4	*
	5	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	6	*
4b420ab4	7	* Written by Ryusuke Konishi.
64b5a32e RK	8	*
	9	*/
	10
	11	#include <linux/buffer_head.h>
	12	#include <linux/writeback.h>
	13	#include <linux/crc32.h>
9c965bac	14	#include <linux/backing-dev.h>
5a0e3ad6	15	#include <linux/slab.h>
64b5a32e RK	16	#include "page.h"
64b5a32e RK	17	#include "segbuf.h"
64b5a32e RK	18
64b5a32e RK	19
9c965bac RK	20	struct nilfs_write_info {
	21	struct the_nilfs *nilfs;
	22	struct bio *bio;
55480a06	23	int start, end; /* The region to be submitted */
9c965bac RK	24	int rest_blocks;
	25	int max_pages;
	26	int nr_vecs;
	27	sector_t blocknr;
	28	};
	29
d1c6b72a RK	30	static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
	31	struct the_nilfs *nilfs);
	32	static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
	33
64b5a32e RK	34	struct nilfs_segment_buffer nilfs_segbuf_new(struct super_block sb)
	35	{
	36	struct nilfs_segment_buffer *segbuf;
	37
	38	segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
	39	if (unlikely(!segbuf))
	40	return NULL;
	41
	42	segbuf->sb_super = sb;
	43	INIT_LIST_HEAD(&segbuf->sb_list);
	44	INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
	45	INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
1e2b68bf	46	segbuf->sb_super_root = NULL;
9284ad2a RK	47
	48	init_completion(&segbuf->sb_bio_event);
	49	atomic_set(&segbuf->sb_err, 0);
	50	segbuf->sb_nbio = 0;
	51
64b5a32e RK	52	return segbuf;
	53	}
	54
	55	void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
	56	{
64b5a32e RK	57	kmem_cache_free(nilfs_segbuf_cachep, segbuf);
	58	}
	59
cece5520	60	void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
64b5a32e RK	61	unsigned long offset, struct the_nilfs *nilfs)
64b5a32e RK	62	{
64b5a32e RK	63	segbuf->sb_segnum = segnum;
	64	nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
	65	&segbuf->sb_fseg_end);
	66
	67	segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
	68	segbuf->sb_rest_blocks =
	69	segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
64b5a32e RK	70	}
64b5a32e RK	71
a694291a RK	72	/**
	73	* nilfs_segbuf_map_cont - map a new log behind a given log
	74	* @segbuf: new segment buffer
	75	* @prev: segment buffer containing a log to be continued
	76	*/
	77	void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
	78	struct nilfs_segment_buffer *prev)
	79	{
	80	segbuf->sb_segnum = prev->sb_segnum;
	81	segbuf->sb_fseg_start = prev->sb_fseg_start;
	82	segbuf->sb_fseg_end = prev->sb_fseg_end;
	83	segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
	84	segbuf->sb_rest_blocks =
	85	segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
	86	}
	87
64b5a32e RK	88	void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
	89	__u64 nextnum, struct the_nilfs *nilfs)
	90	{
	91	segbuf->sb_nextnum = nextnum;
	92	segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
	93	}
	94
	95	int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
	96	{
	97	struct buffer_head *bh;
	98
	99	bh = sb_getblk(segbuf->sb_super,
	100	segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
	101	if (unlikely(!bh))
	102	return -ENOMEM;
	103
	104	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
	105	return 0;
	106	}
	107
	108	int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
	109	struct buffer_head **bhp)
	110	{
	111	struct buffer_head *bh;
	112
	113	bh = sb_getblk(segbuf->sb_super,
	114	segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
	115	if (unlikely(!bh))
	116	return -ENOMEM;
	117
	118	nilfs_segbuf_add_payload_buffer(segbuf, bh);
	119	*bhp = bh;
	120	return 0;
	121	}
	122
0c6c44cb	123	int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
fb04b91b	124	time64_t ctime, __u64 cno)
64b5a32e RK	125	{
	126	int err;
	127
	128	segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
	129	err = nilfs_segbuf_extend_segsum(segbuf);
	130	if (unlikely(err))
	131	return err;
	132
	133	segbuf->sb_sum.flags = flags;
	134	segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
	135	segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
	136	segbuf->sb_sum.ctime = ctime;
50614bcf	137	segbuf->sb_sum.cno = cno;
64b5a32e RK	138	return 0;
	139	}
	140
	141	/*
7a65004b	142	* Setup segment summary
64b5a32e RK	143	*/
	144	void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
	145	{
	146	struct nilfs_segment_summary *raw_sum;
	147	struct buffer_head *bh_sum;
	148
	149	bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
	150	struct buffer_head, b_assoc_buffers);
	151	raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
	152
	153	raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC);
	154	raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum));
	155	raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags);
	156	raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq);
	157	raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime);
	158	raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next);
	159	raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks);
	160	raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
	161	raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
	162	raw_sum->ss_pad = 0;
50614bcf	163	raw_sum->ss_cno = cpu_to_le64(segbuf->sb_sum.cno);
64b5a32e RK	164	}
	165
	166	/*
	167	* CRC calculation routines
	168	*/
aaed1d5b RK	169	static void
aaed1d5b RK	170	nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
64b5a32e RK	171	{
	172	struct buffer_head *bh;
	173	struct nilfs_segment_summary *raw_sum;
	174	unsigned long size, bytes = segbuf->sb_sum.sumbytes;
	175	u32 crc;
	176
	177	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
	178	b_assoc_buffers);
	179
	180	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
	181	size = min_t(unsigned long, bytes, bh->b_size);
	182	crc = crc32_le(seed,
	183	(unsigned char *)raw_sum +
	184	sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
	185	size - (sizeof(raw_sum->ss_datasum) +
	186	sizeof(raw_sum->ss_sumsum)));
	187
	188	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
	189	b_assoc_buffers) {
	190	bytes -= size;
	191	size = min_t(unsigned long, bytes, bh->b_size);
	192	crc = crc32_le(crc, bh->b_data, size);
	193	}
	194	raw_sum->ss_sumsum = cpu_to_le32(crc);
	195	}
	196
aaed1d5b RK	197	static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
aaed1d5b RK	198	u32 seed)
64b5a32e RK	199	{
	200	struct buffer_head *bh;
	201	struct nilfs_segment_summary *raw_sum;
	202	void *kaddr;
	203	u32 crc;
	204
	205	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
	206	b_assoc_buffers);
	207	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
	208	crc = crc32_le(seed,
	209	(unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
	210	bh->b_size - sizeof(raw_sum->ss_datasum));
	211
	212	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
	213	b_assoc_buffers) {
	214	crc = crc32_le(crc, bh->b_data, bh->b_size);
	215	}
	216	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
7b9c0976	217	kaddr = kmap_atomic(bh->b_page);
64b5a32e	218	crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
7b9c0976	219	kunmap_atomic(kaddr);
64b5a32e RK	220	}
	221	raw_sum->ss_datasum = cpu_to_le32(crc);
	222	}
	223
aaed1d5b RK	224	static void
	225	nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
	226	u32 seed)
	227	{
	228	struct nilfs_super_root *raw_sr;
6c6de1aa	229	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
0c6c44cb	230	unsigned int srsize;
aaed1d5b RK	231	u32 crc;
	232
	233	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
6c6de1aa	234	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
aaed1d5b RK	235	crc = crc32_le(seed,
aaed1d5b RK	236	(unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
6c6de1aa	237	srsize - sizeof(raw_sr->sr_sum));
aaed1d5b RK	238	raw_sr->sr_sum = cpu_to_le32(crc);
	239	}
	240
e29df395	241	static void nilfs_release_buffers(struct list_head *list)
64b5a32e RK	242	{
	243	struct buffer_head bh, n;
	244
	245	list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
	246	list_del_init(&bh->b_assoc_buffers);
64b5a32e RK	247	brelse(bh);
	248	}
	249	}
	250
e29df395 RK	251	static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
	252	{
	253	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
	254	nilfs_release_buffers(&segbuf->sb_payload_buffers);
1e2b68bf	255	segbuf->sb_super_root = NULL;
e29df395 RK	256	}
	257
	258	/*
	259	* Iterators for segment buffers
	260	*/
	261	void nilfs_clear_logs(struct list_head *logs)
	262	{
	263	struct nilfs_segment_buffer *segbuf;
	264
	265	list_for_each_entry(segbuf, logs, sb_list)
	266	nilfs_segbuf_clear(segbuf);
	267	}
	268
	269	void nilfs_truncate_logs(struct list_head *logs,
	270	struct nilfs_segment_buffer *last)
	271	{
	272	struct nilfs_segment_buffer n, segbuf;
	273
	274	segbuf = list_prepare_entry(last, logs, sb_list);
	275	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
	276	list_del_init(&segbuf->sb_list);
	277	nilfs_segbuf_clear(segbuf);
	278	nilfs_segbuf_free(segbuf);
	279	}
	280	}
	281
d1c6b72a RK	282	int nilfs_write_logs(struct list_head logs, struct the_nilfs nilfs)
	283	{
	284	struct nilfs_segment_buffer *segbuf;
	285	int ret = 0;
	286
	287	list_for_each_entry(segbuf, logs, sb_list) {
	288	ret = nilfs_segbuf_write(segbuf, nilfs);
	289	if (ret)
	290	break;
	291	}
	292	return ret;
	293	}
	294
e29df395 RK	295	int nilfs_wait_on_logs(struct list_head *logs)
	296	{
	297	struct nilfs_segment_buffer *segbuf;
d067633b	298	int err, ret = 0;
e29df395 RK	299
	300	list_for_each_entry(segbuf, logs, sb_list) {
	301	err = nilfs_segbuf_wait(segbuf);
d067633b RK	302	if (err && !ret)
d067633b RK	303	ret = err;
e29df395	304	}
d067633b	305	return ret;
e29df395 RK	306	}
e29df395 RK	307
aaed1d5b RK	308	/**
	309	* nilfs_add_checksums_on_logs - add checksums on the logs
	310	* @logs: list of segment buffers storing target logs
	311	* @seed: checksum seed value
	312	*/
	313	void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
	314	{
	315	struct nilfs_segment_buffer *segbuf;
	316
	317	list_for_each_entry(segbuf, logs, sb_list) {
	318	if (segbuf->sb_super_root)
	319	nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
	320	nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
	321	nilfs_segbuf_fill_in_data_crc(segbuf, seed);
	322	}
	323	}
	324
64b5a32e RK	325	/*
	326	* BIO operations
	327	*/
4246a0b6	328	static void nilfs_end_bio_write(struct bio *bio)
64b5a32e	329	{
9284ad2a	330	struct nilfs_segment_buffer *segbuf = bio->bi_private;
64b5a32e	331
4e4cbee9	332	if (bio->bi_status)
9284ad2a	333	atomic_inc(&segbuf->sb_err);
64b5a32e RK	334
64b5a32e RK	335	bio_put(bio);
9284ad2a	336	complete(&segbuf->sb_bio_event);
64b5a32e RK	337	}
64b5a32e RK	338
9284ad2a	339	static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
b2d45866 MC	340	struct nilfs_write_info *wi, int mode,
b2d45866 MC	341	int mode_flags)
64b5a32e RK	342	{
	343	struct bio *bio = wi->bio;
	344	int err;
	345
026a7d63 RK	346	if (segbuf->sb_nbio > 0 &&
026a7d63 RK	347	bdi_write_congested(segbuf->sb_super->s_bdi)) {
9284ad2a RK	348	wait_for_completion(&segbuf->sb_bio_event);
	349	segbuf->sb_nbio--;
	350	if (unlikely(atomic_read(&segbuf->sb_err))) {
64b5a32e RK	351	bio_put(bio);
	352	err = -EIO;
	353	goto failed;
	354	}
	355	}
	356
	357	bio->bi_end_io = nilfs_end_bio_write;
9284ad2a	358	bio->bi_private = segbuf;
b2d45866	359	bio_set_op_attrs(bio, mode, mode_flags);
4e49ea4a	360	submit_bio(bio);
4bf93b50	361	segbuf->sb_nbio++;
64b5a32e RK	362
	363	wi->bio = NULL;
	364	wi->rest_blocks -= wi->end - wi->start;
	365	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
	366	wi->start = wi->end;
	367	return 0;
	368
	369	failed:
	370	wi->bio = NULL;
	371	return err;
	372	}
	373
	374	/**
9c965bac RK	375	* nilfs_alloc_seg_bio - allocate a new bio for writing log
	376	* @nilfs: nilfs object
	377	* @start: start block number of the bio
64b5a32e RK	378	* @nr_vecs: request size of page vector.
64b5a32e RK	379	*
64b5a32e RK	380	* Return Value: On success, pointer to the struct bio is returned.
	381	* On error, NULL is returned.
	382	*/
9c965bac	383	static struct bio nilfs_alloc_seg_bio(struct the_nilfs nilfs, sector_t start,
64b5a32e RK	384	int nr_vecs)
	385	{
	386	struct bio *bio;
	387
c1b353f0	388	bio = bio_alloc(GFP_NOIO, nr_vecs);
64b5a32e RK	389	if (bio == NULL) {
64b5a32e RK	390	while (!bio && (nr_vecs >>= 1))
c1b353f0	391	bio = bio_alloc(GFP_NOIO, nr_vecs);
64b5a32e RK	392	}
64b5a32e RK	393	if (likely(bio)) {
74d46992	394	bio_set_dev(bio, nilfs->ns_bdev);
4f024f37 KO	395	bio->bi_iter.bi_sector =
4f024f37 KO	396	start << (nilfs->ns_blocksize_bits - 9);
64b5a32e RK	397	}
	398	return bio;
	399	}
	400
9c965bac RK	401	static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
9c965bac RK	402	struct nilfs_write_info *wi)
64b5a32e RK	403	{
	404	wi->bio = NULL;
	405	wi->rest_blocks = segbuf->sb_sum.nblocks;
b54ffb73	406	wi->max_pages = BIO_MAX_PAGES;
64b5a32e RK	407	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
64b5a32e RK	408	wi->start = wi->end = 0;
64b5a32e	409	wi->blocknr = segbuf->sb_pseg_start;
64b5a32e RK	410	}
64b5a32e RK	411
9284ad2a RK	412	static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
	413	struct nilfs_write_info *wi,
	414	struct buffer_head *bh, int mode)
64b5a32e RK	415	{
	416	int len, err;
	417
	418	BUG_ON(wi->nr_vecs <= 0);
	419	repeat:
	420	if (!wi->bio) {
9c965bac	421	wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
64b5a32e RK	422	wi->nr_vecs);
	423	if (unlikely(!wi->bio))
	424	return -ENOMEM;
	425	}
	426
	427	len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
	428	if (len == bh->b_size) {
	429	wi->end++;
	430	return 0;
	431	}
	432	/* bio is FULL */
b2d45866	433	err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
64b5a32e RK	434	/* never submit current bh */
	435	if (likely(!err))
	436	goto repeat;
	437	return err;
	438	}
	439
9c965bac RK	440	/**
	441	* nilfs_segbuf_write - submit write requests of a log
	442	* @segbuf: buffer storing a log to be written
	443	* @nilfs: nilfs object
	444	*
	445	* Return Value: On Success, 0 is returned. On Error, one of the following
	446	* negative error code is returned.
	447	*
	448	* %-EIO - I/O error
	449	*
	450	* %-ENOMEM - Insufficient memory available.
	451	*/
6c477d44 RK	452	static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
6c477d44 RK	453	struct the_nilfs *nilfs)
64b5a32e	454	{
9c965bac	455	struct nilfs_write_info wi;
64b5a32e	456	struct buffer_head *bh;
b2d45866	457	int res = 0;
64b5a32e	458
9c965bac RK	459	wi.nilfs = nilfs;
	460	nilfs_segbuf_prepare_write(segbuf, &wi);
	461
64b5a32e	462	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
b2d45866	463	res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
64b5a32e RK	464	if (unlikely(res))
	465	goto failed_bio;
	466	}
	467
	468	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
b2d45866	469	res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
64b5a32e RK	470	if (unlikely(res))
	471	goto failed_bio;
	472	}
	473
9c965bac	474	if (wi.bio) {
64b5a32e RK	475	/*
	476	* Last BIO is always sent through the following
	477	* submission.
	478	*/
b2d45866 MC	479	res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
b2d45866 MC	480	REQ_SYNC);
64b5a32e RK	481	}
64b5a32e RK	482
64b5a32e	483	failed_bio:
5f1586d0	484	return res;
64b5a32e RK	485	}
	486
	487	/**
	488	* nilfs_segbuf_wait - wait for completion of requested BIOs
9284ad2a	489	* @segbuf: segment buffer
64b5a32e RK	490	*
	491	* Return Value: On Success, 0 is returned. On Error, one of the following
	492	* negative error code is returned.
	493	*
	494	* %-EIO - I/O error
	495	*/
6c477d44	496	static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
64b5a32e RK	497	{
	498	int err = 0;
	499
9284ad2a	500	if (!segbuf->sb_nbio)
64b5a32e RK	501	return 0;
	502
	503	do {
9284ad2a RK	504	wait_for_completion(&segbuf->sb_bio_event);
9284ad2a RK	505	} while (--segbuf->sb_nbio > 0);
64b5a32e	506
9284ad2a	507	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
a1d0747a	508	nilfs_err(segbuf->sb_super,
feee880f RK	509	"I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
	510	(unsigned long long)segbuf->sb_pseg_start,
	511	segbuf->sb_sum.nblocks,
	512	(unsigned long long)segbuf->sb_segnum);
64b5a32e	513	err = -EIO;
64b5a32e RK	514	}
	515	return err;
	516	}