From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 69322EB64DC for ; Wed, 21 Jun 2023 18:49:02 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1qC2t2-00085H-Bd; Wed, 21 Jun 2023 18:49:00 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1qC2st-00084g-Vf; Wed, 21 Jun 2023 18:48:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=MIME-Version:Content-Transfer-Encoding:Content-Type :References:In-Reply-To:Date:To:From:Subject:Message-ID:Sender:Reply-To:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=A1kbXwuqBdSEgrCme3vFF6i7KkR5+tPtLwHXAbS02LM=; b=bEAFISxBoTSzLY+5vSpdjN/P8R yWFaXxeerukpQS4NzBXfJ2J/G1DJcxren1MtpZQRX/XZrDkaN7+zDbw52rbJa6KL0GOUOyOhogwDt v+pJLnPByed6ANsarP87KKKJoxizwxQvwGkptz8qjrAJidIl4W27rxdgSJ92QbmS0WKM=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:To:From:Subject:Message-ID:Sender:Reply-To:Cc:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=A1kbXwuqBdSEgrCme3vFF6i7KkR5+tPtLwHXAbS02LM=; b=MxyMYtStewzy7RNRg3SO3LQS3t /xbqHwI+QA6lF7pUe4OxeiHeaZyuot6mfDhXZWMThDUuNm6Ln8PL2BzcqO/OKw25nyHWnA0GyJe6C faUblc0aBSbqr5kVvPj6wUhxfAO0N6B28rv+vaeYYeZRwq1YP9m+lIZt57EzOLGV3pgI=; Received: from dfw.source.kernel.org ([139.178.84.217]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1qC2sk-0004JW-I1; Wed, 21 Jun 2023 18:48:51 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 75C6F616AB; Wed, 21 Jun 2023 18:48:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB234C433C8; Wed, 21 Jun 2023 18:48:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687373315; bh=a5OpkE0TU4uPAvSOWcyUKhr2U/OaDDTahqvZpyNm/D4=; h=Subject:From:To:Date:In-Reply-To:References:From; b=PiPk49g+MFOu/O2ZwDxO/8QAjKIZGlhjql5KOg56o+z0jsrDavO9BiaXOtkYto876 fJ7qYzZ7aATc9kPncdP1kCdlY5wqINNGdYK2LGj2HmV63uWD5NHZ4+OFVQ4t30vFE9 rYDpgx917Jc/lUMtGxdnWxKlhyndYbn3MftPxoStquXW6wJVzxk1ZBM8Z7BTbv2h/U qJjwHaLWN8lUJ3h6C5OcO+D166wrcNaWoWGX2W/vO7mNHZJIsw6euWqEIeYa7S4lF3 jaX3jg20U9mjcF803nObNGAx9i1QbKIM3FZeyHr6EhjkD9DNtiQVqDSkHfY1GNj8rV 9eRPHwtyQHGGQ== Message-ID: From: Jeff Layton To: Tom Talpey , Jeremy Kerr , Arnd Bergmann , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Greg Kroah-Hartman , Arve =?ISO-8859-1?Q?Hj=F8nnev=E5g?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Carlos Llamas , Suren Baghdasaryan , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Brad Warrum , Ritu Agarwal , Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , Christian Schoenebeck , David Sterba , David Howells , Marc Dionne , Alexander Viro , Ian Kent , Luis de Bethencourt , Salah Triki , "Tigran A. 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De Francesco" , Chen Zhongjin , Zhengchao Shao , Rik van Riel , Jingyu Wang , Hangyu Hua , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, linux-usb@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org, autofs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, codalist@coda.cs.cmu.edu, ecryptfs@vger.kernel.org, linux-efi@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-um@lists.infradead.org, linux-mtd@lists.infradead.org, jfs-discussion@lists.sourceforge.net, linux-nfs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, ntfs3@lists.linux.dev, ocfs2-devel@oss.oracle.com, linux-karma-devel@lists.sourceforge.net, devel@lists.orangefs.org, linux-unionfs@vger.kernel.org, linux-hardening@vger.kernel.org, reiserfs-devel@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-trace-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Date: Wed, 21 Jun 2023 14:48:17 -0400 In-Reply-To: References: <20230621144507.55591-1-jlayton@kernel.org> <20230621144507.55591-2-jlayton@kernel.org> <1f97d595-e035-46ce-6269-eebfe922cf35@talpey.com> <6f4bcd7d79f688120d80e96e86d7c521854d8e84.camel@kernel.org> User-Agent: Evolution 3.48.3 (3.48.3-1.fc38) MIME-Version: 1.0 X-Headers-End: 1qC2sk-0004JW-I1 Subject: Re: [f2fs-dev] [PATCH 01/79] fs: add ctime accessors infrastructure X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Wed, 2023-06-21 at 14:19 -0400, Tom Talpey wrote: > On 6/21/2023 2:01 PM, Jeff Layton wrote: > > On Wed, 2023-06-21 at 13:29 -0400, Tom Talpey wrote: > > > On 6/21/2023 10:45 AM, Jeff Layton wrote: > > > > struct timespec64 has unused bits in the tv_nsec field that can be used > > > > for other purposes. In future patches, we're going to change how the > > > > inode->i_ctime is accessed in certain inodes in order to make use of > > > > them. In order to do that safely though, we'll need to eradicate raw > > > > accesses of the inode->i_ctime field from the kernel. > > > > > > > > Add new accessor functions for the ctime that we can use to replace them. > > > > > > > > Signed-off-by: Jeff Layton > > > > --- > > > > fs/inode.c | 16 ++++++++++++++ > > > > include/linux/fs.h | 53 +++++++++++++++++++++++++++++++++++++++++++++- > > > > 2 files changed, 68 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/fs/inode.c b/fs/inode.c > > > > index d37fad91c8da..c005e7328fbb 100644 > > > > --- a/fs/inode.c > > > > +++ b/fs/inode.c > > > > @@ -2499,6 +2499,22 @@ struct timespec64 current_time(struct inode *inode) > > > > } > > > > EXPORT_SYMBOL(current_time); > > > > > > > > +/** > > > > + * inode_ctime_set_current - set the ctime to current_time > > > > + * @inode: inode > > > > + * > > > > + * Set the inode->i_ctime to the current value for the inode. Returns > > > > + * the current value that was assigned to i_ctime. > > > > + */ > > > > +struct timespec64 inode_ctime_set_current(struct inode *inode) > > > > +{ > > > > + struct timespec64 now = current_time(inode); > > > > + > > > > + inode_set_ctime(inode, now); > > > > + return now; > > > > +} > > > > +EXPORT_SYMBOL(inode_ctime_set_current); > > > > + > > > > /** > > > > * in_group_or_capable - check whether caller is CAP_FSETID privileged > > > > * @idmap: idmap of the mount @inode was found from > > > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > > > index 6867512907d6..9afb30606373 100644 > > > > --- a/include/linux/fs.h > > > > +++ b/include/linux/fs.h > > > > @@ -1474,7 +1474,58 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb, > > > > kgid_has_mapping(fs_userns, kgid); > > > > } > > > > > > > > -extern struct timespec64 current_time(struct inode *inode); > > > > +struct timespec64 current_time(struct inode *inode); > > > > +struct timespec64 inode_ctime_set_current(struct inode *inode); > > > > + > > > > +/** > > > > + * inode_ctime_peek - fetch the current ctime from the inode > > > > + * @inode: inode from which to fetch ctime > > > > + * > > > > + * Grab the current ctime from the inode and return it. > > > > + */ > > > > +static inline struct timespec64 inode_ctime_peek(const struct inode *inode) > > > > +{ > > > > + return inode->i_ctime; > > > > +} > > > > + > > > > +/** > > > > + * inode_ctime_set - set the ctime in the inode to the given value > > > > + * @inode: inode in which to set the ctime > > > > + * @ts: timespec value to set the ctime > > > > + * > > > > + * Set the ctime in @inode to @ts. > > > > + */ > > > > +static inline struct timespec64 inode_ctime_set(struct inode *inode, struct timespec64 ts) > > > > +{ > > > > + inode->i_ctime = ts; > > > > + return ts; > > > > +} > > > > + > > > > +/** > > > > + * inode_ctime_set_sec - set only the tv_sec field in the inode ctime > > > > > > I'm curious about why you choose to split the tv_sec and tv_nsec > > > set_ functions. Do any callers not set them both? Wouldn't a > > > single call enable a more atomic behavior someday? > > > > > > inode_ctime_set_sec_nsec(struct inode *, time64_t, time64_t) > > > > > > (or simply initialize a timespec64 and use inode_ctime_spec() ) > > > > > > > Yes, quite a few places set the fields individually. For example, when > > loading a value from disk that doesn't have sufficient granularity to > > set the nsecs field to anything but 0. > > Well, they still need to set the tv_nsec so they could just pass 0. > But ok. > Sure. The difficulty is in trying to do this in an automated way. For instance, look at the hfsplus patch; it has separate assignments in place already: - result->i_ctime.tv_sec = result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date)); - result->i_ctime.tv_nsec = 0; + inode_ctime_set_sec(result, + result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date))); + inode_ctime_set_nsec(result, 0); Granted the new code is pretty ugly, but it compiles! Transforming that into what you're suggesting is a tougher proposition to do with coccinelle. I didn't see a way to conditionally catch cases like this, declare a new variable in the appropriate spot and then transform two assignments (that may not be next to one another!) into a single one. Maybe it's possible, but my grasp of SMPL is not that great. The docs and examples (including Kees' vey helpful ones!) cover fairly simple changes well, but I didn't quite grasp how to do that complex an evolution. > > Could I have done it by declaring a local timespec64 variable and just > > use the inode_ctime_set function in these places? Absolutely. > > > > That's a bit more difficult to handle with coccinelle though. If someone > > wants to suggest a way to do that without having to change all of these > > call sites manually, then I'm open to redoing the set. > > > > That might be better left for a later cleanup though. > > Acked-by: Tom Talpey > Many thanks! > > > > + * @inode: inode in which to set the ctime > > > > + * @sec: value to set the tv_sec field > > > > + * > > > > + * Set the sec field in the ctime. Returns @sec. > > > > + */ > > > > +static inline time64_t inode_ctime_set_sec(struct inode *inode, time64_t sec) > > > > +{ > > > > + inode->i_ctime.tv_sec = sec; > > > > + return sec; > > > > +} > > > > + > > > > +/** > > > > + * inode_ctime_set_nsec - set only the tv_nsec field in the inode ctime > > > > + * @inode: inode in which to set the ctime > > > > + * @nsec: value to set the tv_nsec field > > > > + * > > > > + * Set the nsec field in the ctime. Returns @nsec. > > > > + */ > > > > +static inline long inode_ctime_set_nsec(struct inode *inode, long nsec) > > > > +{ > > > > + inode->i_ctime.tv_nsec = nsec; > > > > + return nsec; > > > > +} > > > > > > > > /* > > > > * Snapshotting support. > > -- Jeff Layton _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel