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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D31DC433F5 for ; Sat, 30 Oct 2021 12:05:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5250C60FC4 for ; Sat, 30 Oct 2021 12:05:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231840AbhJ3MIC (ORCPT ); Sat, 30 Oct 2021 08:08:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:58514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231886AbhJ3MIB (ORCPT ); Sat, 30 Oct 2021 08:08:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPS id CA6BA60FC4 for ; Sat, 30 Oct 2021 12:05:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635595531; bh=7APYYEYuGcNLgvNyCqtQUXtjM8xH19kT/lvPRsFyE00=; h=From:To:Subject:Date:In-Reply-To:References:From; b=GYnlpK6yaLWj92jcM3s53uX3zknm9BwfurL5036FDISIqz6TTRgCkLnDR/uQrS3wA +BJhKtV+Mc795e0u4LitMQshvKqLt74UMFsSx13exEQUfk7HC4/hn2KEoAQk57Gu6I 4VO+Lim8iMfOkxWOWI1M92vj/6HVUUPqwf4T7IEOHmY/uB1Kvy6KK2ix5lIQi9SrlC Vzdm0EniEcSHvz3OC1Y+mCXm/sUXICNtcfZmWuv8h8dRxTW19pFueefsgmyjOpjmYq Nwk8utn1wapGWBAcs9PFQzD7y3RP41LH66d5KuQMzAd3ln55EB1VNhswliOpxDLJSI S2dXohqdfnbWA== From: bugzilla-daemon@bugzilla.kernel.org To: linux-man@vger.kernel.org Subject: [Bug 214873] man 2 fsync implies possibility to return early Date: Sat, 30 Oct 2021 12:05:31 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo documentation_man-pages@kernel-bugs.osdl.org X-Bugzilla-Product: Documentation X-Bugzilla-Component: man-pages X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: low X-Bugzilla-Who: alx.manpages@gmail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: documentation_man-pages@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=3D214873 --- Comment #1 from Alejandro Colomar (man-pages) (alx.manpages@gmail.com) = --- [CC +=3D LKML and a few kernel programmers] Hi, On 10/29/21 23:25, bugzilla-daemon@bugzilla.kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=3D214873 >=20 > Bug ID: 214873 > Summary: man 2 fsync implies possibility to return early > Product: Documentation > Version: unspecified > Hardware: All > OS: Linux > Status: NEW > Severity: low > Priority: P1 > Component: man-pages > Assignee: documentation_man-pages@kernel-bugs.osdl.org > Reporter: sworddragon2@gmail.com > Regression: No >=20 > The manpage for the fsync system call ( > https://man7.org/linux/man-pages/man2/fsync.2.html ) describes as flushing > the > related caches to a storage device so that the information can even be > retrieved after a crash/reboot. But then it does make the statement "The = call > blocks until the device reports that the transfer has completed." which > causes > now some interpretation: What happens if the device reports early complet= ion > (e.g. via a bugged firmware) of the transfer while the kernel still sees > unsent > caches in its context? Does fsync() indeed return then as the last refere= nced > sentence implies or does it continue to send the caches the kernel sees to > guarantee data integrity as good as possible as the previous documented p= art > might imply? >=20 > I noticed this discrepancy when reporting a bug against dd ( > https://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D51345 ) that causes dd to > return > early when it is used with its fsync capability while the kernel still se= es > caches and consulting the fsync() manpage made it not clear if such a > theoretical possibility from the fsync() system call would be intended or= not > so eventually this part could be slighty enhanced. >=20 I don't know how fsync(2) works. Could some kernel fs programmer please=20 check if the text matches the implementation, and if that issue reported=20 should be reworded in the manual page? Thanks, Alex --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=