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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C733C3F6B0 for ; Tue, 16 Aug 2022 13:43:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235841AbiHPNn1 (ORCPT ); Tue, 16 Aug 2022 09:43:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234951AbiHPNnX (ORCPT ); Tue, 16 Aug 2022 09:43:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD26B2F39C; Tue, 16 Aug 2022 06:43:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B84B260B82; Tue, 16 Aug 2022 13:43:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C8D6C433C1; Tue, 16 Aug 2022 13:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660657398; bh=QIPlexrcPxp8haxZEg3yRa1ZyJXIsUHjDdZO4hjWJrc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=OeEhbnj1A0851OoNaseJnzt/IVxXEVKgwkqjOOShD7v+62B1LAYvuuKz1jLrHiPyO W6BhJSAWCU4ps0oHxB39b0IHiAzlMDho/OrALMzjtF5Lvko+1+Rk3+fuszvj81l12p F042CypOlWQY8W3B8cNVBxceVmGTtRABK2qm/1qXRc6lTwR/FYsGfqLpJAZsJLGFOO V17Of2ZPCWvmzLLNzG42B0VRX16OYwcA6nWA0w30ID5YgaLW8xYuqHZDrTPnzkcfPD PpTMcClrjRhlFr4kZKXoYM2Gm0eZXooMjnHbssH4CpAkaHndH3/IyJbFZoGD0S94aY P7pJT7zIjdymg== Message-ID: <46ecd0f938ecdc508505456f76e767e0ffcc7137.camel@kernel.org> Subject: Re: [PATCH] ext4: fix i_version handling in ext4 From: Jeff Layton To: Christian Brauner Cc: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, Lukas Czerner , Jan Kara Date: Tue, 16 Aug 2022 09:43:16 -0400 In-Reply-To: <20220816133340.mtaa7mxmgvhzffoh@wittgenstein> References: <20220816131522.42467-1-jlayton@kernel.org> <20220816133340.mtaa7mxmgvhzffoh@wittgenstein> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-1.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, 2022-08-16 at 15:33 +0200, Christian Brauner wrote: > On Tue, Aug 16, 2022 at 09:15:22AM -0400, Jeff Layton wrote: > > ext4 currently updates the i_version counter when the atime is updated > > during a read. This is less than ideal as it can cause unnecessary cach= e > > invalidations with NFSv4. The increment in ext4_mark_iloc_dirty is also > > problematic since it can also corrupt the i_version counter for > > ea_inodes. > >=20 > > We aren't bumping the file times in ext4_mark_iloc_dirty, so changing > > the i_version there seems wrong, and is the cause of both problems. > > Remove that callsite and add increments to the setattr and setxattr > > codepaths (at the same time that we update the ctime). The i_version > > bump that already happens during timestamp updates should take care of > > the rest. > >=20 > > Cc: Lukas Czerner > > Cc: Jan Kara > > Cc: Christian Brauner > > Signed-off-by: Jeff Layton > > --- >=20 > Seems good to me. But it seems that the xfs patch you sent does have > inode_inc_version() right after setattr_copy() as well. So I wonder if > we couldn't just try and move inode_inc_version() into setattr_copy() > itself. >=20 We probably could, but setattr_copy has a lot of callers and most filesystems don't need this. Also, there are some cases where we don't want to update the i_version after a setattr. In particular, if you do a truncate and the size doesn't change, then you really don't want to update the timestamps (and therefore the i_version shouldn't change either). > > fs/ext4/inode.c | 10 +++++----- > > fs/ext4/xattr.c | 2 ++ > > 2 files changed, 7 insertions(+), 5 deletions(-) > >=20 > > I think this patch should probably supersede Lukas' patch entitled: > >=20 > > ext4: don't increase iversion counter for ea_inodes > >=20 > > This will also mean that we'll need to respin the patch to turn on the > > i_version counter unconditionally in ext4 (though that should be > > trivial). > >=20 > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index 601214453c3a..a70921df89a5 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -5342,6 +5342,7 @@ int ext4_setattr(struct user_namespace *mnt_usern= s, struct dentry *dentry, > > int error, rc =3D 0; > > int orphan =3D 0; > > const unsigned int ia_valid =3D attr->ia_valid; > > + bool inc_ivers =3D IS_IVERSION(inode); > > =20 > > if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) > > return -EIO; > > @@ -5425,8 +5426,8 @@ int ext4_setattr(struct user_namespace *mnt_usern= s, struct dentry *dentry, > > return -EINVAL; > > } > > =20 > > - if (IS_I_VERSION(inode) && attr->ia_size !=3D inode->i_size) > > - inode_inc_iversion(inode); > > + if (attr->ia_size =3D=3D inode->i_size) > > + inc_ivers =3D false; > > =20 > > if (shrink) { > > if (ext4_should_order_data(inode)) { > > @@ -5528,6 +5529,8 @@ int ext4_setattr(struct user_namespace *mnt_usern= s, struct dentry *dentry, > > } > > =20 > > if (!error) { > > + if (inc_ivers) > > + inode_inc_iversion(inode); > > setattr_copy(mnt_userns, inode, attr); > > mark_inode_dirty(inode); > > } > > @@ -5731,9 +5734,6 @@ int ext4_mark_iloc_dirty(handle_t *handle, > > } > > ext4_fc_track_inode(handle, inode); > > =20 > > - if (IS_I_VERSION(inode)) > > - inode_inc_iversion(inode); > > - > > /* the do_update_inode consumes one bh->b_count */ > > get_bh(iloc->bh); > > =20 > > diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c > > index 533216e80fa2..4d84919d1c9c 100644 > > --- a/fs/ext4/xattr.c > > +++ b/fs/ext4/xattr.c > > @@ -2412,6 +2412,8 @@ ext4_xattr_set_handle(handle_t *handle, struct in= ode *inode, int name_index, > > if (!error) { > > ext4_xattr_update_super_block(handle, inode->i_sb); > > inode->i_ctime =3D current_time(inode); > > + if (IS_IVERSION(inode)) > > + inode_inc_iversion(inode); > > if (!value) > > no_expand =3D 0; > > error =3D ext4_mark_iloc_dirty(handle, inode, &is.iloc); > > --=20 > > 2.37.2 > >=20 --=20 Jeff Layton