linux-kernel - Re: [PATCH v1 3/3] VFS/knfsd: Teach dentry_create() to use atomic

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Message-ID: <A0B89B6B-A025-47EB-A54B-79384ACABBEB@hammerspace.com>
Date: Tue, 18 Nov 2025 13:39:51 -0500
From: Benjamin Coddington <bcodding@...merspace.com>
To: Mike Snitzer <snitzer@...nel.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
 Chuck Lever <chuck.lever@...cle.com>, Jeff Layton <jlayton@...nel.org>,
 NeilBrown <neil@...wn.name>, Olga Kornievskaia <okorniev@...hat.com>,
 Dai Ngo <Dai.Ngo@...cle.com>, Tom Talpey <tom@...pey.com>,
 linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-nfs@...r.kernel.org, Trond Myklebust <trondmy@...nel.org>
Subject: Re: [PATCH v1 3/3] VFS/knfsd: Teach dentry_create() to use
 atomic_open()

On 18 Nov 2025, at 13:01, Mike Snitzer wrote:

> On Tue, Nov 18, 2025 at 11:33:59AM -0500, Benjamin Coddington wrote:
>
>>  	path.mnt = fhp->fh_export->ex_path.mnt;
>> -	path.dentry = child;
>> +	path.dentry = *child;
>>  	filp = dentry_create(&path, oflags, open->op_iattr.ia_mode,
>>  			     current_cred());
>> +	*child = path.dentry;
>> +
>>  	if (IS_ERR(filp))
>>  		return nfserrno(PTR_ERR(filp));
>>
>
> Given the potential for side-effect due to dentry_create() now using
> atomic_open() if available, I think you'd do well to update the
> comment block above dentry_create to make it clear that the caller
> really should pass along the dentry (regardless of whether
> dentry_create returns an ERR_PTR).

I will update the comment block to make it clear that the dentry you sent on
@path may be changed.

Ben