Re: [PATCH v9 19/24] xfs: Simplify xfs_attr_leaf_addname

[Allison Collins <allison.henderson@xxxxxxxxxx>]

On 5/4/20 12:03 PM, Darrick J. Wong wrote:
> On Thu, Apr 30, 2020 at 03:50:11PM -0700, Allison Collins wrote:
> > Quick patch to unnest the rename logic in the leaf code path.  This will
> > help simplify delayed attr logic later.
>
> This isn't really an unnesting, is it?  We're inverting the if logic and
> flipping the subordinate blocks.
>
> "Invert the rename logic in xfs_attr_leaf_addname to simplify the
> delayed attr logic later."
Alrighty, will fix

> > Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
> > ---
> >   fs/xfs/libxfs/xfs_attr.c | 108 +++++++++++++++++++++++------------------------
> >   1 file changed, 53 insertions(+), 55 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> > index ab1c9fa..1810f90 100644
> > --- a/fs/xfs/libxfs/xfs_attr.c
> > +++ b/fs/xfs/libxfs/xfs_attr.c
> > @@ -694,73 +694,71 @@ xfs_attr_leaf_addname(
> >   			return error;
> >   	}
> >   
> > -	/*
> > -	 * If this is an atomic rename operation, we must "flip" the
> > -	 * incomplete flags on the "new" and "old" attribute/value pairs
> > -	 * so that one disappears and one appears atomically.  Then we
> > -	 * must remove the "old" attribute/value pair.
> > -	 */
> > -	if (args->op_flags & XFS_DA_OP_RENAME) {
> > +	if ((args->op_flags & XFS_DA_OP_RENAME) == 0) {
>
> 	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
Sure, will flip.  Thanks!

Allison
> --D
>
> >   		/*
> > -		 * In a separate transaction, set the incomplete flag on the
> > -		 * "old" attr and clear the incomplete flag on the "new" attr.
> > -		 */
> > -		error = xfs_attr3_leaf_flipflags(args);
> > -		if (error)
> > -			return error;
> > -		/*
> > -		 * Commit the flag value change and start the next trans in
> > -		 * series.
> > +		 * Added a "remote" value, just clear the incomplete flag.
> >   		 */
> > -		error = xfs_trans_roll_inode(&args->trans, args->dp);
> > -		if (error)
> > -			return error;
> > +		if (args->rmtblkno > 0)
> > +			error = xfs_attr3_leaf_clearflag(args);
> >   
> > -		/*
> > -		 * Dismantle the "old" attribute/value pair by removing
> > -		 * a "remote" value (if it exists).
> > -		 */
> > -		xfs_attr_restore_rmt_blk(args);
> > +		return error;
> > +	}
> >   
> > -		if (args->rmtblkno) {
> > -			error = xfs_attr_rmtval_invalidate(args);
> > -			if (error)
> > -				return error;
> > +	/*
> > +	 * If this is an atomic rename operation, we must "flip" the incomplete
> > +	 * flags on the "new" and "old" attribute/value pairs so that one
> > +	 * disappears and one appears atomically.  Then we must remove the "old"
> > +	 * attribute/value pair.
> > +	 *
> > +	 * In a separate transaction, set the incomplete flag on the "old" attr
> > +	 * and clear the incomplete flag on the "new" attr.
> > +	 */
> >   
> > -			error = xfs_attr_rmtval_remove(args);
> > -			if (error)
> > -				return error;
> > -		}
> > +	error = xfs_attr3_leaf_flipflags(args);
> > +	if (error)
> > +		return error;
> > +	/*
> > +	 * Commit the flag value change and start the next trans in series.
> > +	 */
> > +	error = xfs_trans_roll_inode(&args->trans, args->dp);
> > +	if (error)
> > +		return error;
> >   
> > -		/*
> > -		 * Read in the block containing the "old" attr, then
> > -		 * remove the "old" attr from that block (neat, huh!)
> > -		 */
> > -		error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
> > -					   &bp);
> > +	/*
> > +	 * Dismantle the "old" attribute/value pair by removing a "remote" value
> > +	 * (if it exists).
> > +	 */
> > +	xfs_attr_restore_rmt_blk(args);
> > +
> > +	if (args->rmtblkno) {
> > +		error = xfs_attr_rmtval_invalidate(args);
> >   		if (error)
> >   			return error;
> >   
> > -		xfs_attr3_leaf_remove(bp, args);
> > -
> > -		/*
> > -		 * If the result is small enough, shrink it all into the inode.
> > -		 */
> > -		if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
> > -			error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
> > -			/* bp is gone due to xfs_da_shrink_inode */
> > -			if (error)
> > -				return error;
> > -		}
> > -
> > -	} else if (args->rmtblkno > 0) {
> > -		/*
> > -		 * Added a "remote" value, just clear the incomplete flag.
> > -		 */
> > -		error = xfs_attr3_leaf_clearflag(args);
> > +		error = xfs_attr_rmtval_remove(args);
> >   		if (error)
> >   			return error;
> >   	}
> > +
> > +	/*
> > +	 * Read in the block containing the "old" attr, then remove the "old"
> > +	 * attr from that block (neat, huh!)
> > +	 */
> > +	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
> > +				   &bp);
> > +	if (error)
> > +		return error;
> > +
> > +	xfs_attr3_leaf_remove(bp, args);
> > +
> > +	/*
> > +	 * If the result is small enough, shrink it all into the inode.
> > +	 */
> > +	forkoff = xfs_attr_shortform_allfit(bp, dp);
> > +	if (forkoff)
> > +		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
> > +		/* bp is gone due to xfs_da_shrink_inode */
> > +
> >   	return error;
> >   }
> >   
> > --
> > 2.7.4