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 8688E2F12CF; Mon, 3 Nov 2025 13:14:00 +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=1762175641; cv=none; b=BSCgQiCSUrHjx55v1M39EtoBu/hXXrWLR/yEnPYCoqcm0m0Kzi+I6lJI1DDzAlfUvwIxxU4n44eIoVTA5ErjItWGJKtD92/iVYsut4PY+Nz9X5+ENv4yqHxHGqIbBCMSzawBcQRYYeo0RUxt336YX0bWRu+MS5xOepi8A9PpPyI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762175641; c=relaxed/simple; bh=tQGMDshqT1FdsN10GyeMA+rzP5rgifnOuTWraMMxb2o=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=E0ODWIYQI61f/weEqbtoNixMjl8KHytqMgOmUlnsuVJc4kkc4zO96gbUvyi1DM/4s6kPzdzNp0JdDW2XQOETOQhqzSD0eb5YOhpox94LM5Z1XcE0ieTSxImaUhV1YBdix8oWCxW5yTRQzAKRkOUbd5LSaDrouZeV6KYTY0JA/PU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mt4NWBRz; 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="mt4NWBRz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE7E7C4CEFD; Mon, 3 Nov 2025 13:13:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762175640; bh=tQGMDshqT1FdsN10GyeMA+rzP5rgifnOuTWraMMxb2o=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=mt4NWBRzMjNzXzWfs6jmUEVZtiQsakxer/xla+AFy0HZlkwd1u8rgVScOSTRzk91V M+Ni0mKkIu/uTPWZSFuyZD/XFSLE3WsKbSucKqiCt+kDsNO9zFu12Q7OknkhcISsFM WlWAjPeyS43ZYKYsKZOTVX4Pc141TkqYB0JDLkpwp3EzfD6Cpgryrjp45wS9W4H21h c+210M1hMV+LYwdy8rQ0gho4eqO5aSHiv1e1Z1VJxL0FeGnkFxuK+9dv7zMtIIOzrn HlPFJ+EWBgD7QVLmb8K22+ZlyD3qGP2BhyZLIm54gid8FWLj8nEHcfNl20i0kU2F+H 7I4hTIxNkucSQ== Message-ID: <77334f66ec58a7f3238d8924fc5f1b161183f069.camel@kernel.org> Subject: Re: [PATCH v4 17/17] vfs: expose delegation support to userland From: Jeff Layton To: Miklos Szeredi , Alexander Viro , Christian Brauner , Jan Kara , 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 Cc: 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: Mon, 03 Nov 2025 08:13:55 -0500 In-Reply-To: <20251103-dir-deleg-ro-v4-17-961b67adee89@kernel.org> References: <20251103-dir-deleg-ro-v4-0-961b67adee89@kernel.org> <20251103-dir-deleg-ro-v4-17-961b67adee89@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 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recallable directory delegations is available, > expose this functionality to userland with new F_SETDELEG and F_GETDELEG > 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 > --- > fs/fcntl.c | 14 ++++++++++++++ > fs/locks.c | 42 +++++++++++++++++++++++++++++++++++++---= -- > include/linux/filelock.h | 12 ++++++++++++ > include/uapi/linux/fcntl.h | 10 ++++++++++ > 4 files changed, 73 insertions(+), 5 deletions(-) >=20 [...] > + > +void fcntl_getdeleg(struct file *filp, struct delegation *deleg) > +{ > + deleg->d_type =3D __fcntl_getlease(filp, FL_DELEG); > +} > + It occurs to me that this function should probably check d_flags and return an error like fcntl_setlease() does. I'm testing this now in my own tree. Returning an error on flags that the kernel doesn't understand seems like the right thing to do. Thoughts? --------------8<--------------- commit 92dcb7653003dc74edf29f07347d19271d629818 Author: Jeff Layton Date: Mon Nov 3 07:59:19 2025 -0500 SQUASH: make fcntl_getdeleg check d_flags too =20 Signed-off-by: Jeff Layton diff --git a/fs/fcntl.c b/fs/fcntl.c index 8d57a6e34076..f93dbca08435 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -554,10 +554,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigne= d long arg, case F_GETDELEG: if (copy_from_user(&deleg, argp, sizeof(deleg))) return -EFAULT; - fcntl_getdeleg(filp, &deleg); - if (copy_to_user(argp, &deleg, sizeof(deleg))) + err =3D fcntl_getdeleg(filp, &deleg); + if (!err && copy_to_user(argp, &deleg, sizeof(deleg))) return -EFAULT; - err =3D 0; break; case F_SETDELEG: if (copy_from_user(&deleg, argp, sizeof(deleg))) diff --git a/fs/locks.c b/fs/locks.c index 1e29aecf79b8..c52f6a7b6a5c 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1736,9 +1736,12 @@ int fcntl_getlease(struct file *filp) return __fcntl_getlease(filp, FL_LEASE); } =20 -void fcntl_getdeleg(struct file *filp, struct delegation *deleg) +int fcntl_getdeleg(struct file *filp, struct delegation *deleg) { + if (deleg->d_flags !=3D 0) + return -EINVAL; deleg->d_type =3D __fcntl_getlease(filp, FL_DELEG); + return 0; } =20 /** diff --git a/include/linux/filelock.h b/include/linux/filelock.h index 4384c6f61fad..54b824c05299 100644 --- a/include/linux/filelock.h +++ b/include/linux/filelock.h @@ -160,7 +160,7 @@ int fcntl_setlk64(unsigned int, struct file *, unsigned= int, int fcntl_setlease(unsigned int fd, struct file *filp, int arg); int fcntl_getlease(struct file *filp); int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *= deleg); -void fcntl_getdeleg(struct file *filp, struct delegation *deleg); +int fcntl_getdeleg(struct file *filp, struct delegation *deleg); =20 static inline bool lock_is_unlock(struct file_lock *fl) { @@ -287,7 +287,7 @@ static inline int fcntl_setdeleg(unsigned int fd, struc= t file *filp, struct dele =20 static inline int fcntl_getdeleg(struct file *filp, struct delegation *del= eg) { - return F_UNLCK; + return -EINVAL; } =20 static inline bool lock_is_unlock(struct file_lock *fl)