Re: [RFC v2 11/14] xfs: expose block size in stat

Darrick J. Wong
2024-02-13T16:27:05Z

On Tue, Feb 13, 2024 at 10:37:10AM +0100, Pankaj Raghav (Samsung) wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> For block size larger than page size, the unit of efficient IO is
> the block size, not the page size. Leaving stat() to report
> PAGE_SIZE as the block size causes test programs like fsx to issue
> illegal ranges for operations that require block size alignment
> (e.g. fallocate() insert range). Hence update the preferred IO size
> to reflect the block size in this case.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> [mcgrof: forward rebase in consideration for commit
> dd2d535e3fb29d ("xfs: cleanup calculating the stat optimal I/O size")]
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
> fs/xfs/xfs_iops.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index a0d77f5f512e..8791a9d80897 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -515,6 +515,8 @@ xfs_stat_blksize(
> struct xfs_inode *ip)
> {
> struct xfs_mount *mp = ip->i_mount;
> + unsigned long default_size = max_t(unsigned long, PAGE_SIZE,
> + mp->m_sb.sb_blocksize);

Nit: wonky indentation, but...

>
> /*
> * If the file blocks are being allocated from a realtime volume, then
> @@ -543,7 +545,7 @@ xfs_stat_blksize(
> return 1U << mp->m_allocsize_log;
> }
>
> - return PAGE_SIZE;
> + return default_size;

...why not return max_t(...) directly here?

--D

> }
>
> STATIC int
> --
> 2.43.0
>
>