Re: [PATCH v3 2/2] xfs: clean up calculation of LR header blocks

[Brian Foster <bfoster@redhat.com>]

On Thu, Sep 17, 2020 at 01:13:41PM +0800, Gao Xiang wrote:
> Let's use DIV_ROUND_UP() to calculate log record header
> blocks as what did in xlog_get_iclog_buffer_size() and
> wrap up a common helper for log recovery.
> 
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
> v2: https://lore.kernel.org/r/20200904082516.31205-3-hsiangkao@redhat.com
> 
> changes since v2:
>  - get rid of xlog_logrecv2_hblks() and use xlog_logrec_hblks()
>    entirely (Brian).
> 
>  fs/xfs/xfs_log.c         |  4 +---
>  fs/xfs/xfs_log_recover.c | 48 ++++++++++++++--------------------------
>  2 files changed, 17 insertions(+), 35 deletions(-)
> 
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index ad0c69ee8947..7a4ba408a3a2 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -1604,9 +1604,7 @@ xlog_cksum(
>  		int		i;
>  		int		xheads;
>  
> -		xheads = size / XLOG_HEADER_CYCLE_SIZE;
> -		if (size % XLOG_HEADER_CYCLE_SIZE)
> -			xheads++;
> +		xheads = DIV_ROUND_UP(size, XLOG_HEADER_CYCLE_SIZE);
>  
>  		for (i = 1; i < xheads; i++) {
>  			crc = crc32c(crc, &xhdr[i].hic_xheader,
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index 782ec3eeab4d..28dd98b5a703 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -371,6 +371,18 @@ xlog_find_verify_cycle(
>  	return error;
>  }
>  
> +static inline int xlog_logrec_hblks(struct xlog *log, xlog_rec_header_t *rh)
> +{

We're trying to gradually eliminate various structure typedefs so it's
frowned upon to introduce new instances. If you replace the above with
'struct xlog_rec_header,' the rest looks good to me:

Reviewed-by: Brian Foster <bfoster@redhat.com>

> +	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
> +		int	h_size = be32_to_cpu(rh->h_size);
> +
> +		if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
> +		    h_size > XLOG_HEADER_CYCLE_SIZE)
> +			return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
> +	}
> +	return 1;
> +}
> +
>  /*
>   * Potentially backup over partial log record write.
>   *
> @@ -463,15 +475,7 @@ xlog_find_verify_log_record(
>  	 * reset last_blk.  Only when last_blk points in the middle of a log
>  	 * record do we update last_blk.
>  	 */
> -	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
> -		uint	h_size = be32_to_cpu(head->h_size);
> -
> -		xhdrs = h_size / XLOG_HEADER_CYCLE_SIZE;
> -		if (h_size % XLOG_HEADER_CYCLE_SIZE)
> -			xhdrs++;
> -	} else {
> -		xhdrs = 1;
> -	}
> +	xhdrs = xlog_logrec_hblks(log, head);
>  
>  	if (*last_blk - i + extra_bblks !=
>  	    BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
> @@ -1158,22 +1162,7 @@ xlog_check_unmount_rec(
>  	 * below. We won't want to clear the unmount record if there is one, so
>  	 * we pass the lsn of the unmount record rather than the block after it.
>  	 */
> -	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
> -		int	h_size = be32_to_cpu(rhead->h_size);
> -		int	h_version = be32_to_cpu(rhead->h_version);
> -
> -		if ((h_version & XLOG_VERSION_2) &&
> -		    (h_size > XLOG_HEADER_CYCLE_SIZE)) {
> -			hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
> -			if (h_size % XLOG_HEADER_CYCLE_SIZE)
> -				hblks++;
> -		} else {
> -			hblks = 1;
> -		}
> -	} else {
> -		hblks = 1;
> -	}
> -
> +	hblks = xlog_logrec_hblks(log, rhead);
>  	after_umount_blk = xlog_wrap_logbno(log,
>  			rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
>  
> @@ -2989,15 +2978,10 @@ xlog_do_recovery_pass(
>  		if (error)
>  			goto bread_err1;
>  
> -		if ((be32_to_cpu(rhead->h_version) & XLOG_VERSION_2) &&
> -		    (h_size > XLOG_HEADER_CYCLE_SIZE)) {
> -			hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
> -			if (h_size % XLOG_HEADER_CYCLE_SIZE)
> -				hblks++;
> +		hblks = xlog_logrec_hblks(log, rhead);
> +		if (hblks != 1) {
>  			kmem_free(hbp);
>  			hbp = xlog_alloc_buffer(log, hblks);
> -		} else {
> -			hblks = 1;
>  		}
>  	} else {
>  		ASSERT(log->l_sectBBsize == 1);
> -- 
> 2.18.1
>