From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A11F0357711; Tue, 11 Nov 2025 12:14:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762863285; cv=none; b=AzqTi7UjPt+M2ueC5rM4fWRvdPjnEfDBQEI5VaiueYdW94APTQ3wzfk06/cy2N92BZk/lSna2BJmYCHsXquz7o26viBVP/+gVPueGxjNmMQkQyIvo2Ca7pHKU/HyNbRjVHGWjyhzDZZIrKcsC96213k3d93c920OYmk008qzyGU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762863285; c=relaxed/simple; bh=+rzKQWAbRHUg4ouBJteUhgLiy1lvAwd+xZ2GORVTZyM=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=mdW7+gyEWnaNZOk5MefMGkiT44hzxEzZsYI91ATKjsLS+YLek5XfCSakkuLlxXfWb1U5fUu/XGeZ8JRdV++HXqWDPKD9uVRnh1GTVLMHqw8K77VTOty/ftqwULBmD1+otSj77Cmw7a4VEgeLUpTS/6ul30sxeT0DPil/AAlIDk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L8+p8JpV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L8+p8JpV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEFA8C16AAE; Tue, 11 Nov 2025 12:14:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762863285; bh=+rzKQWAbRHUg4ouBJteUhgLiy1lvAwd+xZ2GORVTZyM=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=L8+p8JpVK7PTEkla3qKRiaprmCyYkFkm3RFmbLOQ+JWWKk7+ZMQWwI3ZWJQSouxXT 3ediEo5XyLbdJjUFNBQ6uuyhtSGizG0OZGr4jKhR5Dvlbp1UrgLBAr9ohjtwzEKXeM G1YDLaAbp57K2IDKGVRUig3r9zCCW6UB+KtgZ0xJSjmBvuFw4BlxXY1t9zQUFi5IzL 4PksDCXtKYKJ4PLRQLxlY6LzZm16nK/tGZwcVOpZHddjo2mHvGH+clbQeWI7WdwHL7 m0cBBE9o1zBeYd+fUA+PUWV0Lbw321Qzal+objZ6KSEKZLc22Iris+EiobHa6jX+WR nA98vwSRcRnHw== Message-ID: <4dd0e1f2dd1ef5103d54e1dceeb2a18fbf7d1e63.camel@kernel.org> Subject: Re: [PATCH v5 17/17] vfs: expose delegation support to userland From: Jeff Layton To: Jan Kara Cc: Miklos Szeredi , Alexander Viro , Christian Brauner , Chuck Lever , Alexander Aring , Trond Myklebust , Anna Schumaker , Steve French , Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , David Howells , Tyler Hicks , NeilBrown , Olga Kornievskaia , Dai Ngo , Amir Goldstein , Namjae Jeon , Steve French , Sergey Senozhatsky , Carlos Maiolino , Kuniyuki Iwashima , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, netfs@lists.linux.dev, ecryptfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, netdev@vger.kernel.org Date: Tue, 11 Nov 2025 07:14:40 -0500 In-Reply-To: References: <20251105-dir-deleg-ro-v5-0-7ebc168a88ac@kernel.org> <20251105-dir-deleg-ro-v5-17-7ebc168a88ac@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV 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available, > > expose this functionality to userland with new F_SETDELEG and F_GETDELE= G > > commands for fcntl(). > >=20 > > Note that this also allows userland to request a FL_DELEG type lease on > > files too. Userland applications that do will get signalled when there > > are metadata changes in addition to just data changes (which is a > > limitation of FL_LEASE leases). > >=20 > > These commands accept a new "struct delegation" argument that contains = a > > flags field for future expansion. > >=20 > > Signed-off-by: Jeff Layton >=20 > For new apis CCing linux-api is a good practice ;) >=20 > ... >=20 Doh! I definitely will on the next posting. > > diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h > > index 3741ea1b73d8500061567b6590ccf5fb4c6770f0..8123fe70e03cfb1ba9ce1b5= e20d61b62e462a7ea 100644 > > --- a/include/uapi/linux/fcntl.h > > +++ b/include/uapi/linux/fcntl.h > > @@ -79,6 +79,16 @@ > > */ > > #define RWF_WRITE_LIFE_NOT_SET RWH_WRITE_LIFE_NOT_SET > > =20 > > +/* Set/Get delegations */ > > +#define F_GETDELEG (F_LINUX_SPECIFIC_BASE + 15) > > +#define F_SETDELEG (F_LINUX_SPECIFIC_BASE + 16) > > + > > +/* Argument structure for F_GETDELEG and F_SETDELEG */ > > +struct delegation { > > + unsigned int d_flags; /* Must be 0 */ > > + short d_type; /* F_RDLCK, F_WRLCK, F_UNLCK */ > > +}; > > + >=20 > I think it would make sense for d_type to be unsigned since it's more or > less enum. >=20 FWIW, struct flock has the l_type as a signed short, so that's why I copied it here. Making it unsigned is better though. > Also struct delegation is going to have a hole in it at the end > which is always a concern with uAPI structures (passing around > uninitialized stuff). I think it would be good to put an explicit padding > there and enforce it is zeroed out. >=20 Makes sense. I'll incorporate that too. Thanks! --=20 Jeff Layton