Re: [PATCH v8 1/5] xfs: update lazy sb counters immediately for resizefs

[Brian Foster <bfoster@redhat.com>]

On Fri, Mar 05, 2021 at 10:56:59AM +0800, Gao Xiang wrote:
> sb_fdblocks will be updated lazily if lazysbcount is enabled,
> therefore when shrinking the filesystem sb_fdblocks could be
> larger than sb_dblocks and xfs_validate_sb_write() would fail.
> 
> Even for growfs case, it'd be better to update lazy sb counters
> immediately to reflect the real sb counters.
> 
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---

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

>  fs/xfs/xfs_fsops.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index a2a407039227..9f9ba8bd0213 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -128,6 +128,15 @@ xfs_growfs_data_private(
>  				 nb - mp->m_sb.sb_dblocks);
>  	if (id.nfree)
>  		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree);
> +
> +	/*
> +	 * Sync sb counters now to reflect the updated values. This is
> +	 * particularly important for shrink because the write verifier
> +	 * will fail if sb_fdblocks is ever larger than sb_dblocks.
> +	 */
> +	if (xfs_sb_version_haslazysbcount(&mp->m_sb))
> +		xfs_log_sb(tp);
> +
>  	xfs_trans_set_sync(tp);
>  	error = xfs_trans_commit(tp);
>  	if (error)
> -- 
> 2.27.0
>