From patchwork Fri Sep 22 17:14:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 13396046 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 9E04CCD484C for ; Fri, 22 Sep 2023 17:15:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233027AbjIVRPL (ORCPT ); Fri, 22 Sep 2023 13:15:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232804AbjIVRPA (ORCPT ); Fri, 22 Sep 2023 13:15:00 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DC17199; Fri, 22 Sep 2023 10:14:54 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48015C433CC; Fri, 22 Sep 2023 17:14:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695402893; bh=fUxZuWZUND6whtfSXS6cbk4dZFYYjP9h1aQMSYrQkf8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=rBTSD5KCp99SdJZqsG3zOYy+AdArnEo24hL2QnlNNWA+rKd1uSMkLvysYgASAy8nk 0bbFIkNgBgvgbU6sAOFtzG8gk4ZsxaREY53V7g3eHNwfXbEq1lkcdapAwrdViQaT/k VybJ+BJ43c6IBag3RVLgPWv06U40KwYdJ8Ioud2e5unfr+FUyD7mIJHHgIwXPqxgVf y+SwAq2s6t5VVWHcNNkUPRjfi7Gapjlq2PvqQpUprYxExjc72PfhZ6Bh9cP7axAQj4 HmyUf2kpRcyIMpzHzmKDgWaHMPnzUidPabG+MyH68FApeyLyLjaO3IXolT7e8BpPLH PN3yx8F2/QmyQ== From: Jeff Layton Date: Fri, 22 Sep 2023 13:14:42 -0400 Subject: [PATCH v8 3/5] fs: have setattr_copy handle multigrain timestamps appropriately MIME-Version: 1.0 Message-Id: <20230922-ctime-v8-3-45f0c236ede1@kernel.org> References: <20230922-ctime-v8-0-45f0c236ede1@kernel.org> In-Reply-To: <20230922-ctime-v8-0-45f0c236ede1@kernel.org> To: Alexander Viro , Christian Brauner , Chuck Lever , Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Chandan Babu R , "Darrick J. Wong" , Dave Chinner , Jan Kara , Linus Torvalds Cc: Kent Overstreet , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org, Jeff Layton X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3299; i=jlayton@kernel.org; h=from:subject:message-id; bh=fUxZuWZUND6whtfSXS6cbk4dZFYYjP9h1aQMSYrQkf8=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBlDcuGMi53UoH/W19WSq89zn8S9TZbYu1oTRu0z xom55+Yu6WJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZQ3LhgAKCRAADmhBGVaC FandEACrYrCK4mEHxIf2BJs2N6vjBIybMKu/4Io+i4XF+mOOk6726NojyEhKuk2vcXIZDgoSvko 4sKNNH5HJsvVR4C/pSNdKBjr9POUoEZoVvbpAVLy2iu2ejCm9nZwOl2xLwDOHmVWpuGOaEC99N8 slbJjXsc6mQhW4YtY8aiyIe2vWAUJiApGFxe76Xq4LVXwpvlLE59HrPesc8OTs9DlWw1gGcJgBI aGZ5e552ciqXH6M3W0TigkkwuRC/pE4PgFzY4IceN8aQ751zXiaRcePJlCTd8vw48smmMTyIduB 7R0BBtYMOIFAIQLtYFAAzTOA1FXJEm9Z0fj5jaoxBcZKF1dn3wxU5v3JpQzPYlIwiW6Ew2/vE2Y ItlRJO5Cp9KTKFfB/bQQ/DGUJ1QIk9HjeA3wfhGKAJXOajJuBnt0uoMmUn5DMDSweylV3tiMO83 xA84OiIS3hYeTXK1raunHowGVvoXZAK7H+ozYd9dMdvcMfJKrPBUy9YYl5z7l/hYT+OAZUvOkNc VWGpdW7tpulAckFRkllgmsfnvbNszaNeWX483WFWsz6X6Zfv6zQe+mX8S8T9UE4XqE6ZYjDhYKn tE/ezJ+p8Zn6pmB2fWYo7O0PYpLLmzwY9kcFm3H2MawZtSwNtcpY1I8f1CBDtMzSw3qgeoYiOhq kKQ6H5ktDrpyWUQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The setattr codepath is still using coarse-grained timestamps, even on multigrain filesystems. To fix this, we need to fetch the timestamp for ctime updates later, at the point where the assignment occurs in setattr_copy. On a multigrain inode, ignore the ia_ctime in the attrs, and always update the ctime to the current clock value. Update the atime and mtime with the same value (if needed) unless they are being set to other specific values, a'la utimes(). Note that we don't want to do this universally however, as some filesystems (e.g. most networked fs) want to do an explicit update elsewhere before updating the local inode. Signed-off-by: Jeff Layton --- fs/attr.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 6 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index a8ae5f6d9b16..8ba330e6a582 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -275,6 +275,42 @@ int inode_newsize_ok(const struct inode *inode, loff_t offset) } EXPORT_SYMBOL(inode_newsize_ok); +/** + * setattr_copy_mgtime - update timestamps for mgtime inodes + * @inode: inode timestamps to be updated + * @attr: attrs for the update + * + * With multigrain timestamps, we need to take more care to prevent races + * when updating the ctime. Always update the ctime to the very latest + * using the standard mechanism, and use that to populate the atime and + * mtime appropriately (unless we're setting those to specific values). + */ +static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr) +{ + unsigned int ia_valid = attr->ia_valid; + struct timespec64 now; + + /* + * If the ctime isn't being updated then nothing else should be + * either. + */ + if (!(ia_valid & ATTR_CTIME)) { + WARN_ON_ONCE(ia_valid & (ATTR_ATIME|ATTR_MTIME)); + return; + } + + now = inode_set_ctime_current(inode); + if (ia_valid & ATTR_ATIME_SET) + inode->i_atime = attr->ia_atime; + else if (ia_valid & ATTR_ATIME) + inode->i_atime = now; + + if (ia_valid & ATTR_MTIME_SET) + inode->i_mtime = attr->ia_mtime; + else if (ia_valid & ATTR_MTIME) + inode->i_mtime = now; +} + /** * setattr_copy - copy simple metadata updates into the generic inode * @idmap: idmap of the mount the inode was found from @@ -307,12 +343,6 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, i_uid_update(idmap, attr, inode); i_gid_update(idmap, attr, inode); - if (ia_valid & ATTR_ATIME) - inode->i_atime = attr->ia_atime; - if (ia_valid & ATTR_MTIME) - inode->i_mtime = attr->ia_mtime; - if (ia_valid & ATTR_CTIME) - inode_set_ctime_to_ts(inode, attr->ia_ctime); if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; if (!in_group_or_capable(idmap, inode, @@ -320,6 +350,16 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, mode &= ~S_ISGID; inode->i_mode = mode; } + + if (is_mgtime(inode)) + return setattr_copy_mgtime(inode, attr); + + if (ia_valid & ATTR_ATIME) + inode->i_atime = attr->ia_atime; + if (ia_valid & ATTR_MTIME) + inode->i_mtime = attr->ia_mtime; + if (ia_valid & ATTR_CTIME) + inode_set_ctime_to_ts(inode, attr->ia_ctime); } EXPORT_SYMBOL(setattr_copy);