From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH 02/11] xfs: add NOWAIT semantics for readdir
Date: Tue, 29 Aug 2023 14:05:10 +0100
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To: Hao Xu <hao.xu@linux.dev>
Cc: io-uring@vger.kernel.org, Jens Axboe <axboe@kernel.dk>, Dominique Martinet <asmadeus@codewreck.org>, Pavel Begunkov <asml.silence@gmail.com>, Christian Brauner <brauner@kernel.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Stefan Roesch <shr@fb.com>, Clay Harris <bugs@claycon.org>, Dave Chinner <david@fromorbit.com>, "Darrick J . Wong" <djwong@kernel.org>, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-cachefs@redhat.com, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, devel@lists.orangefs.

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.