Re: [PATCH 3/6] xfs: don't zero partial page cache pages during O_DIRECT writes

Brian Foster
2014-08-21T13:09:21Z

On Thu, Aug 21, 2014 at 03:09:11PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Similar to direct IO reads, direct IO writes are using
> truncate_pagecache_range to invalidate the page cache. This is
> incorrect due to the sub-block zeroing in the page cache that
> truncate_pagecache_range() triggers.
>
> This patch fixes things by using invalidate_inode_pages2_range
> instead. It preserves the page cache invalidation, but won't zero
> any pages.
>
> cc: stable@vger.kernel.org
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

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

> fs/xfs/xfs_file.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 827cfb2..19917fa 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -644,7 +644,15 @@ xfs_file_dio_aio_write(
> pos, -1);
> if (ret)
> goto out;
> - truncate_pagecache_range(VFS_I(ip), pos, -1);
> + /*
> + * Invalidate whole pages. This can return an error if
> + * we fail to invalidate a page, but this should never
> + * happen on XFS. Warn if it does fail.
> + */
> + ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
> + pos >> PAGE_CACHE_SHIFT, -1);
> + WARN_ON_ONCE(ret);
> + ret = 0;
> }
>
> /*
> --
> 2.0.0
>
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