On Mon, Sep 12, 2016 at 06:06:43PM +0300, Amir Goldstein wrote:
> Use vfs_copy_file_range() helper instead of calling do_splice_direct()
> when copying up file data.
> When copying up within the same fs, which supports copy_file_range(),
> fs implementation can be more efficient then do_splice_direct().
> vfs_copy_file_range() helper falls back to do_splice_direct() if
> it cannot use the file system's copy_file_range() implementation.
>
> Tested correct behavior when lower and upper are on:
> 1. same ext4 (copy)
> 2. same xfs + reflink patches + mkfs.xfs (copy)
> 3. same xfs + reflink patches + mkfs.xfs -m reflink=1 (clone)
> 4. different xfs + reflink patches + mkfs.xfs -m reflink=1 (copy)
>
> For comparison, on my laptop, xfstest overlay/001 (copy up of large
> sparse files) takes less than 1 second in the xfs reflink setup vs.
> 25 seconds on the rest of the setups.
This is now stale, right? the reflink is done from the
vfs_clone_file_range() call added in an earlier patch, not this
change....
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/overlayfs/copy_up.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
> index e432d7e..32ea54f 100644
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@ -159,15 +159,16 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
> break;
> }
>
> - bytes = do_splice_direct(old_file, &old_pos,
> - new_file, &new_pos,
> - this_len, SPLICE_F_MOVE);
> + bytes = vfs_copy_file_range(old_file, old_pos,
> + new_file, new_pos,
> + this_len, 0);
> if (bytes <= 0) {
> error = bytes;
> break;
> }
> - WARN_ON(old_pos != new_pos);
>
> + old_pos += bytes;
> + new_pos += bytes;
> len -= bytes;
> }
Patch does not remove the
/* FIXME: copy up sparse files efficiently */
comment. Efficient copying of sparse files is something
vfs_copy_file_range() should do internally....
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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