Re: [PATCH v9 20/24] xfs: Simplify xfs_attr_node_addname

[Allison Collins <allison.henderson@xxxxxxxxxx>]

On 5/5/20 6:12 AM, Brian Foster wrote:
> On Thu, Apr 30, 2020 at 03:50:12PM -0700, Allison Collins wrote:
> > Quick patch to unnest the rename logic in the node code path.  This will
> > help simplify delayed attr logic later.
> >
> > Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
> > ---
> >   fs/xfs/libxfs/xfs_attr.c | 131 +++++++++++++++++++++++------------------------
> >   1 file changed, 64 insertions(+), 67 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> > index 1810f90..9171895 100644
> > --- a/fs/xfs/libxfs/xfs_attr.c
> > +++ b/fs/xfs/libxfs/xfs_attr.c
> > @@ -1030,83 +1030,80 @@ xfs_attr_node_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) {
> > -		/*
> > -		 * 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)
> > -			goto out;
> > +	if ((args->op_flags & XFS_DA_OP_RENAME) == 0) {
> >   		/*
> > -		 * 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)
> > -			goto out;
> > +		if (args->rmtblkno > 0)
> > +			error = xfs_attr3_leaf_clearflag(args);
> > +		retval = error;
>
> Can we just init retval to 0 and avoid this assignment? With that and
> similar fixups to the previous patch:
Sure, will do.

> Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
>
> Note that I'm also of the mind to break this down into smaller functions
> depending on what later patches look like, but if there's more to
> consider around that this seems like a good step in that direction.
Sure, and that's fine too if we change our minds later.  I just figured 
I see what people thought of this first.  Thanks for the reviews!

Allison

> Brian
>
> > +		goto out;
> > +	}
> >   
> > -		/*
> > -		 * Dismantle the "old" attribute/value pair by removing
> > -		 * a "remote" value (if it exists).
> > -		 */
> > -		xfs_attr_restore_rmt_blk(args);
> > +	/*
> > +	 * 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_attr3_leaf_flipflags(args);
> > +	if (error)
> > +		goto out;
> > +	/*
> > +	 * Commit the flag value change and start the next trans in series
> > +	 */
> > +	error = xfs_trans_roll_inode(&args->trans, args->dp);
> > +	if (error)
> > +		goto out;
> >   
> > -		if (args->rmtblkno) {
> > -			error = xfs_attr_rmtval_invalidate(args);
> > -			if (error)
> > -				return error;
> > +	/*
> > +	 * Dismantle the "old" attribute/value pair by removing a "remote" value
> > +	 * (if it exists).
> > +	 */
> > +	xfs_attr_restore_rmt_blk(args);
> >   
> > -			error = xfs_attr_rmtval_remove(args);
> > -			if (error)
> > -				return error;
> > -		}
> > +	if (args->rmtblkno) {
> > +		error = xfs_attr_rmtval_invalidate(args);
> > +		if (error)
> > +			return error;
> >   
> > -		/*
> > -		 * Re-find the "old" attribute entry after any split ops.
> > -		 * The INCOMPLETE flag means that we will find the "old"
> > -		 * attr, not the "new" one.
> > -		 */
> > -		args->attr_filter |= XFS_ATTR_INCOMPLETE;
> > -		state = xfs_da_state_alloc();
> > -		state->args = args;
> > -		state->mp = mp;
> > -		state->inleaf = 0;
> > -		error = xfs_da3_node_lookup_int(state, &retval);
> > +		error = xfs_attr_rmtval_remove(args);
> >   		if (error)
> > -			goto out;
> > +			return error;
> > +	}
> >   
> > -		/*
> > -		 * Remove the name and update the hashvals in the tree.
> > -		 */
> > -		blk = &state->path.blk[ state->path.active-1 ];
> > -		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> > -		error = xfs_attr3_leaf_remove(blk->bp, args);
> > -		xfs_da3_fixhashpath(state, &state->path);
> > +	/*
> > +	 * Re-find the "old" attribute entry after any split ops. The INCOMPLETE
> > +	 * flag means that we will find the "old" attr, not the "new" one.
> > +	 */
> > +	args->attr_filter |= XFS_ATTR_INCOMPLETE;
> > +	state = xfs_da_state_alloc();
> > +	state->args = args;
> > +	state->mp = mp;
> > +	state->inleaf = 0;
> > +	error = xfs_da3_node_lookup_int(state, &retval);
> > +	if (error)
> > +		goto out;
> >   
> > -		/*
> > -		 * Check to see if the tree needs to be collapsed.
> > -		 */
> > -		if (retval && (state->path.active > 1)) {
> > -			error = xfs_da3_join(state);
> > -			if (error)
> > -				goto out;
> > -			error = xfs_defer_finish(&args->trans);
> > -			if (error)
> > -				goto out;
> > -		}
> > +	/*
> > +	 * Remove the name and update the hashvals in the tree.
> > +	 */
> > +	blk = &state->path.blk[state->path.active-1];
> > +	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> > +	error = xfs_attr3_leaf_remove(blk->bp, args);
> > +	xfs_da3_fixhashpath(state, &state->path);
> >   
> > -	} else if (args->rmtblkno > 0) {
> > -		/*
> > -		 * Added a "remote" value, just clear the incomplete flag.
> > -		 */
> > -		error = xfs_attr3_leaf_clearflag(args);
> > +	/*
> > +	 * Check to see if the tree needs to be collapsed.
> > +	 */
> > +	if (retval && (state->path.active > 1)) {
> > +		error = xfs_da3_join(state);
> > +		if (error)
> > +			goto out;
> > +		error = xfs_defer_finish(&args->trans);
> >   		if (error)
> >   			goto out;
> >   	}
> > --
> > 2.7.4