Re: [PATCH 4/6] xfs: call xfs_flush_unmap_range from xfs_free_file_space

Darrick J. Wong
2024-08-27T16:03:24Z

On Tue, Aug 27, 2024 at 08:50:48AM +0200, Christoph Hellwig wrote:
> Call xfs_flush_unmap_range from xfs_free_file_space so that
> xfs_file_fallocate doesn't have to predict which mode will call it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hmm. I /think/ it's ok to shift the xfs_flush_unmap_range after the
file_modified and some of the other EINVAL bailouts that can happen
before xfs_free_file_space gets called. Effectively that means that we
can fail faster now? :)

Later on this means that the cow-around code that the rtreflink patchset
introduces will also get flushed to disk before we start
collapsing/zeroing/punching. AFAICT that should be fine.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
> fs/xfs/xfs_bmap_util.c | 8 ++++++++
> fs/xfs/xfs_file.c | 21 ---------------------
> 2 files changed, 8 insertions(+), 21 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index fe2e2c93097550..187a0dbda24fc4 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -848,6 +848,14 @@ xfs_free_file_space(
> if (len <= 0) /* if nothing being freed */
> return 0;
>
> + /*
> + * Now AIO and DIO has drained we flush and (if necessary) invalidate
> + * the cached range over the first operation we are about to run.
> + */
> + error = xfs_flush_unmap_range(ip, offset, len);
> + if (error)
> + return error;
> +
> startoffset_fsb = XFS_B_TO_FSB(mp, offset);
> endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 4cdc54dc96862e..5b9e49da06013c 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -890,27 +890,6 @@ xfs_file_fallocate(
> */
> inode_dio_wait(inode);
>
> - /*
> - * Now AIO and DIO has drained we flush and (if necessary) invalidate
> - * the cached range over the first operation we are about to run.
> - *
> - * We care about zero and collapse here because they both run a hole
> - * punch over the range first. Because that can zero data, and the range
> - * of invalidation for the shift operations is much larger, we still do
> - * the required flush for collapse in xfs_prepare_shift().
> - *
> - * Insert has the same range requirements as collapse, and we extend the
> - * file first which can zero data. Hence insert has the same
> - * flush/invalidate requirements as collapse and so they are both
> - * handled at the right time by xfs_prepare_shift().
> - */
> - if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE |
> - FALLOC_FL_COLLAPSE_RANGE)) {
> - error = xfs_flush_unmap_range(ip, offset, len);
> - if (error)
> - goto out_unlock;
> - }
> -
> error = file_modified(file);
> if (error)
> goto out_unlock;
> --
> 2.43.0
>
>