linux-kernel - Re: [PATCH] vfs: remove the excl argument from the ->create() inode

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Message-ID: <6758176514cdd6e2ceacb3bd0e4d63fb8784b7c6.camel@kernel.org>
Date: Thu, 06 Nov 2025 07:07:48 -0500
From: Jeff Layton <jlayton@...nel.org>
To: NeilBrown <neil@...wn.name>
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Subject: Re: [PATCH] vfs: remove the excl argument from the ->create()
 inode_operation

On Thu, 2025-11-06 at 08:23 +1100, NeilBrown wrote:
> On Thu, 06 Nov 2025, Jeff Layton wrote:
> > Since ce8644fcadc5 ("lookup_open(): expand the call of vfs_create()"),
> > the "excl" argument to the ->create() inode_operation is always set to
> > true. Remove it, and fix up all of the create implementations.
> 
> nonono
> 
> 
> > @@ -3802,7 +3802,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
> >  		}
> >  
> >  		error = dir_inode->i_op->create(idmap, dir_inode, dentry,
> > -						mode, open_flag & O_EXCL);
> > +						mode);
> 
> "open_flag & O_EXCL" is not the same as "true".
> 
> It is true that "all calls to vfs_create() pass true for 'excl'"
> The same is NOT true for inode_operations.create.
> 

I don't think this is a problem, actually:

Almost all of the existing ->create() operations ignore the "excl"
bool. There are only two that I found that do not: NFS and GFS2. Both
of those have an ->atomic_open() operation though, so lookup_open()
will never call ->create() for those filesystems. This means that -
>create() _is_ always called with excl == true.

-- 
Jeff Layton <jlayton@...nel.org>