On Thu, Dec 14, 2023 at 01:28:08PM -0600, Eric Sandeen wrote:
> Although xfs_growfs_data() doesn't call xfs_growfs_data_private()
> if in->newblocks == mp->m_sb.sb_dblocks, xfs_growfs_data_private()
> further massages the new block count so that we don't i.e. try
> to create a too-small new AG.
>
> This may lead to a delta of "0" in xfs_growfs_data_private(), so
> we end up in the shrink case and emit the EXPERIMENTAL warning
> even if we're not changing anything at all.
>
> Fix this by returning straightaway if the block delta is zero.
>
> (nb: in older kernels, the result of entering the shrink case
> with delta == 0 may actually let an -ENOSPC escape to userspace,
> which is confusing for users.)
>
> Fixes: fb2fc1720185 ("xfs: support shrinking unused space in the last AG")
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Seems like a reasonable addition...
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
>
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 7cb75cb6b8e9..80811d16dde0 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -134,6 +134,10 @@ xfs_growfs_data_private(
> if (delta < 0 && nagcount < 2)
> return -EINVAL;
>
> + /* No work to do */
> + if (delta == 0)
> + return 0;
> +
> oagcount = mp->m_sb.sb_agcount;
> /* allocate the new per-ag structures */
> if (nagcount > oagcount) {
>
>
