Re: [PATCH 02/12] xfs: set IOMAP_F_NEW more carefully

Darrick J. Wong
2019-10-15T18:01:32Z

On Tue, Oct 15, 2019 at 05:43:35PM +0200, Christoph Hellwig wrote:
> Don't set IOMAP_F_NEW if we COW over and existing allocated range, as

"..over an existing..."

> these aren't strictly new allocations. This is required to be able to
> use IOMAP_F_NEW to zero newly allocated blocks, which is required for
> the iomap code to fully support file systems that don't do delayed
> allocations or use unwritten extents.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Other than that,

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/xfs/xfs_iomap.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 54c9ec7ad337..c0a492353826 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -707,9 +707,12 @@ xfs_file_iomap_begin_delay(
> * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
> * them out if the write happens to fail.
> */
> - iomap_flags |= IOMAP_F_NEW;
> - trace_xfs_iomap_alloc(ip, offset, count, whichfork,
> - whichfork == XFS_DATA_FORK ? &imap : &cmap);
> + if (whichfork == XFS_DATA_FORK) {
> + iomap_flags |= IOMAP_F_NEW;
> + trace_xfs_iomap_alloc(ip, offset, count, whichfork, &imap);
> + } else {
> + trace_xfs_iomap_alloc(ip, offset, count, whichfork, &cmap);
> + }
> done:
> if (whichfork == XFS_COW_FORK) {
> if (imap.br_startoff > offset_fsb) {
> --
> 2.20.1
>