Re: [PATCH 02/11] xfs: add NOWAIT semantics for readdir

Matthew Wilcox
2023-08-29T13:06:35Z

On Tue, Aug 29, 2023 at 03:41:43PM +0800, Hao Xu wrote:
> On 8/28/23 04:44, Matthew Wilcox wrote:
> > > @@ -391,10 +401,17 @@ xfs_dir2_leaf_getdents(
> > > bp = NULL;
> > > }
> > > - if (*lock_mode == 0)
> > > - *lock_mode = xfs_ilock_data_map_shared(dp);
> > > + if (*lock_mode == 0) {
> > > + *lock_mode =
> > > + xfs_ilock_data_map_shared_generic(dp,
> > > + ctx->flags & DIR_CONTEXT_F_NOWAIT);
> > > + if (!*lock_mode) {
> > > + error = -EAGAIN;
> > > + break;
> > > + }
> > > + }
> >
> > 'generic' doesn't seem like a great suffix to mean 'takes nowait flag'.
> > And this is far too far indented.
> >
> > xfs_dir2_lock(dp, ctx, lock_mode);
> >
> > with:
> >
> > STATIC void xfs_dir2_lock(struct xfs_inode *dp, struct dir_context *ctx,
> > unsigned int lock_mode)
> > {
> > if (*lock_mode)
> > return;
> > if (ctx->flags & DIR_CONTEXT_F_NOWAIT)
> > return xfs_ilock_data_map_shared_nowait(dp);
> > return xfs_ilock_data_map_shared(dp);
> > }
> >
> > ... which I think you can use elsewhere in this patch (reformat it to
> > XFS coding style, of course). And then you don't need
> > xfs_ilock_data_map_shared_generic().
>
> How about rename xfs_ilock_data_map_shared() to xfs_ilock_data_map_block()
> and rename xfs_ilock_data_map_shared_generic() to
> xfs_ilock_data_map_shared()?
>
> STATIC void xfs_ilock_data_map_shared(struct xfs_inode *dp, struct
> dir_context *ctx, unsigned int lock_mode)
> {
> if (*lock_mode)
> return;
> if (ctx->flags & DIR_CONTEXT_F_NOWAIT)
> return xfs_ilock_data_map_shared_nowait(dp);
> return xfs_ilock_data_map_shared_block(dp);
> }

xfs_ilock_data_map_shared() is used for a lot of things which are not
directories. I think a new function name is appropriate, and that
function name should include the word 'dir' in it somewhere.