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 63F1616F8FA; Wed, 3 Jul 2024 11:19:28 +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=1720005568; cv=none; b=EHAL2dxdo/5MrwGsxUiqc8+s5ALWOccI3C0Uq86b5sSUFjoHNLaBqzTjBQ8AZVDaaXYbcPsGtYwHWRak8C4zJuiMWDsTFLVL4Wcm7qJ+GvWxY+0ZhVDEu9JiMCbuT3rpr3EcVUcCg2olNPOajiWAHtucgcDO5zsfjz3zdpo1im4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720005568; c=relaxed/simple; bh=KsLNKuzD/fkqg4XP1gTs83gohhdH6XBt/Nl9+Xf6SnU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pTvYoNEUOU8nnHrXE/EIkbmC5URdRJyJbvPAd93HUPcxELw50vj7/BVaPp8TMwhtplK8FF45UcnpC+eXqAo6q1DCdbyzIgsiJUJ3a8I2WtJ8dRMRevWp+E/99MbOhYsXeR1E55dyg7nh5PwStK2lsGnlNL/fFGMGx1VJV023ODg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1XS4f38I; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1XS4f38I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD202C2BD10; Wed, 3 Jul 2024 11:19:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720005568; bh=KsLNKuzD/fkqg4XP1gTs83gohhdH6XBt/Nl9+Xf6SnU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1XS4f38IPTYrTyGXDcBLfZPgMcDt7Q0jFhih/ope3KRaT+GcUDyzxoSKYQ1PCHx44 Wupx7sYbzosaL7DWAs5xyvFO/VfBCrndnimpPaMJ4LI9ZhZzdeAXm+oevMmNTwQgCs KFBDozU6oQhRijBZ0bSg0ahUwCpERraX13TYY+vE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Su Yue , Joseph Qi , Mark Fasheh , Joel Becker , Junxiao Bi , Changwei Ge , Gang He , Jun Piao , Andrew Morton Subject: [PATCH 5.15 125/356] ocfs2: use coarse time for new created files Date: Wed, 3 Jul 2024 12:37:41 +0200 Message-ID: <20240703102917.824213004@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703102913.093882413@linuxfoundation.org> References: <20240703102913.093882413@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Su Yue commit b8cb324277ee16f3eca3055b96fce4735a5a41c6 upstream. The default atime related mount option is '-o realtime' which means file atime should be updated if atime <= ctime or atime <= mtime. atime should be updated in the following scenario, but it is not: ========================================================== $ rm /mnt/testfile; $ echo test > /mnt/testfile $ stat -c "%X %Y %Z" /mnt/testfile 1711881646 1711881646 1711881646 $ sleep 5 $ cat /mnt/testfile > /dev/null $ stat -c "%X %Y %Z" /mnt/testfile 1711881646 1711881646 1711881646 ========================================================== And the reason the atime in the test is not updated is that ocfs2 calls ktime_get_real_ts64() in __ocfs2_mknod_locked during file creation. Then inode_set_ctime_current() is called in inode_set_ctime_current() calls ktime_get_coarse_real_ts64() to get current time. ktime_get_real_ts64() is more accurate than ktime_get_coarse_real_ts64(). In my test box, I saw ctime set by ktime_get_coarse_real_ts64() is less than ktime_get_real_ts64() even ctime is set later. The ctime of the new inode is smaller than atime. The call trace is like: ocfs2_create ocfs2_mknod __ocfs2_mknod_locked .... ktime_get_real_ts64 <------- set atime,ctime,mtime, more accurate ocfs2_populate_inode ... ocfs2_init_acl ocfs2_acl_set_mode inode_set_ctime_current current_time ktime_get_coarse_real_ts64 <-------less accurate ocfs2_file_read_iter ocfs2_inode_lock_atime ocfs2_should_update_atime atime <= ctime ? <-------- false, ctime < atime due to accuracy So here call ktime_get_coarse_real_ts64 to set inode time coarser while creating new files. It may lower the accuracy of file times. But it's not a big deal since we already use coarse time in other places like ocfs2_update_inode_atime and inode_set_ctime_current. Link: https://lkml.kernel.org/r/20240408082041.20925-5-glass.su@suse.com Fixes: c62c38f6b91b ("ocfs2: replace CURRENT_TIME macro") Signed-off-by: Su Yue Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Gang He Cc: Jun Piao Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -566,7 +566,7 @@ static int __ocfs2_mknod_locked(struct i fe->i_last_eb_blk = 0; strcpy(fe->i_signature, OCFS2_INODE_SIGNATURE); fe->i_flags |= cpu_to_le32(OCFS2_VALID_FL); - ktime_get_real_ts64(&ts); + ktime_get_coarse_real_ts64(&ts); fe->i_atime = fe->i_ctime = fe->i_mtime = cpu_to_le64(ts.tv_sec); fe->i_mtime_nsec = fe->i_ctime_nsec = fe->i_atime_nsec =