Re: [PATCH RESEND v18 04/11] xfs: Add helper xfs_attr_set_fmt

Darrick J. Wong
2021-05-13T23:46:06Z

On Wed, May 12, 2021 at 09:14:01AM -0700, Allison Henderson wrote:
> This patch adds a helper function xfs_attr_set_fmt. This will help
> isolate the code that will require state management from the portions
> that do not. xfs_attr_set_fmt returns 0 when the attr has been set and
> no further action is needed. It returns -EAGAIN when shortform has been
> transformed to leaf, and the calling function should proceed the set the
> attr in leaf form.
>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
> Reviewed-by: Brian Foster <bfoster@redhat.com>

Er... can't you combine patches 3 and 4 into a single patch that
renames xfs_attr_set_shortform -> xfs_attr_set_fmt and drops the
**leafbp parameter? Smushing the two together it's a bit more obvious
what's really changing here (which really isn't that much!) so:

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

(Though I think I would like the two combined for v19. But let's see
what I think of the whole series by the time I reach the end, eh? :) )

--D

> ---
> fs/xfs/libxfs/xfs_attr.c | 79 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 46 insertions(+), 33 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 32133a0..1a618a2 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -236,6 +236,48 @@ xfs_attr_is_shortform(
> ip->i_afp->if_nextents == 0);
> }
>
> +STATIC int
> +xfs_attr_set_fmt(
> + struct xfs_da_args *args)
> +{
> + struct xfs_buf *leaf_bp = NULL;
> + struct xfs_inode *dp = args->dp;
> + int error2, error = 0;
> +
> + /*
> + * Try to add the attr to the attribute list in the inode.
> + */
> + error = xfs_attr_try_sf_addname(dp, args);
> + if (error != -ENOSPC) {
> + error2 = xfs_trans_commit(args->trans);
> + args->trans = NULL;
> + return error ? error : error2;
> + }
> +
> + /*
> + * It won't fit in the shortform, transform to a leaf block.
> + * GROT: another possible req'mt for a double-split btree op.
> + */
> + error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
> + if (error)
> + return error;
> +
> + /*
> + * Prevent the leaf buffer from being unlocked so that a
> + * concurrent AIL push cannot grab the half-baked leaf buffer
> + * and run into problems with the write verifier.
> + */
> + xfs_trans_bhold(args->trans, leaf_bp);
> + error = xfs_defer_finish(&args->trans);
> + xfs_trans_bhold_release(args->trans, leaf_bp);
> + if (error) {
> + xfs_trans_brelse(args->trans, leaf_bp);
> + return error;
> + }
> +
> + return -EAGAIN;
> +}
> +
> /*
> * Set the attribute specified in @args.
> */
> @@ -244,8 +286,7 @@ xfs_attr_set_args(
> struct xfs_da_args *args)
> {
> struct xfs_inode *dp = args->dp;
> - struct xfs_buf *leaf_bp = NULL;
> - int error2, error = 0;
> + int error;
>
> /*
> * If the attribute list is already in leaf format, jump straight to
> @@ -254,36 +295,9 @@ xfs_attr_set_args(
> * again.
> */
> if (xfs_attr_is_shortform(dp)) {
> - /*
> - * Try to add the attr to the attribute list in the inode.
> - */
> - error = xfs_attr_try_sf_addname(dp, args);
> - if (error != -ENOSPC) {
> - error2 = xfs_trans_commit(args->trans);
> - args->trans = NULL;
> - return error ? error : error2;
> - }
> -
> - /*
> - * It won't fit in the shortform, transform to a leaf block.
> - * GROT: another possible req'mt for a double-split btree op.
> - */
> - error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
> - if (error)
> - return error;
> -
> - /*
> - * Prevent the leaf buffer from being unlocked so that a
> - * concurrent AIL push cannot grab the half-baked leaf buffer
> - * and run into problems with the write verifier.
> - */
> - xfs_trans_bhold(args->trans, leaf_bp);
> - error = xfs_defer_finish(&args->trans);
> - xfs_trans_bhold_release(args->trans, leaf_bp);
> - if (error) {
> - xfs_trans_brelse(args->trans, leaf_bp);
> + error = xfs_attr_set_fmt(args);
> + if (error != -EAGAIN)
> return error;
> - }
> }
>
> if (xfs_attr_is_leaf(dp)) {
> @@ -317,8 +331,7 @@ xfs_attr_set_args(
> return error;
> }
>
> - error = xfs_attr_node_addname(args);
> - return error;
> + return xfs_attr_node_addname(args);
> }
>
> /*
> --
> 2.7.4
>