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

[Brian Foster <bfoster@redhat.com>]

On Wed, Sep 02, 2020 at 10:09:23PM +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
> also wrap up a common helper for log recovery code.
> 
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_log_format.h | 10 +++++++++
>  fs/xfs/xfs_log.c               |  4 +---
>  fs/xfs/xfs_log_recover.c       | 37 ++++++++--------------------------
>  3 files changed, 19 insertions(+), 32 deletions(-)
> 
...
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index e2ec91b2d0f4..5fecc0c7aeb2 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -489,15 +489,10 @@ 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 {
> +	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
> +		xhdrs = xlog_logv2_rec_hblks(head);
> +	else
>  		xhdrs = 1;
> -	}

Can we fold the _haslogv2() check into the helper as well (then perhaps
drop the 'v2' from the name)? Otherwise looks like a nice cleanup to
me..

Brian

>  
>  	if (*last_blk - i + extra_bblks !=
>  	    BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
> @@ -1184,21 +1179,10 @@ 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 {
> +	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
> +		hblks = xlog_logv2_rec_hblks(rhead);
> +	else
>  		hblks = 1;
> -	}
>  
>  	after_umount_blk = xlog_wrap_logbno(log,
>  			rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
> @@ -3016,15 +3000,10 @@ xlog_do_recovery_pass(
>  			}
>  		}
>  
> -		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_logv2_rec_hblks(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
>