From owner-freebsd-bugs@freebsd.org Wed Mar 6 23:07:52 2019 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C06A4152A7F3 for ; Wed, 6 Mar 2019 23:07:52 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 418887597A for ; Wed, 6 Mar 2019 23:07:52 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id F2833152A7F0; Wed, 6 Mar 2019 23:07:51 +0000 (UTC) Delivered-To: bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CE113152A7EF for ; Wed, 6 Mar 2019 23:07:51 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6751875978 for ; Wed, 6 Mar 2019 23:07:51 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id BF6EFCF5E for ; Wed, 6 Mar 2019 23:07:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id x26N7oOR056811 for ; Wed, 6 Mar 2019 23:07:50 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x26N7oGj056802 for bugs@FreeBSD.org; Wed, 6 Mar 2019 23:07:50 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 236340] [FUSE] fuse(4) should pass through O_APPEND to the filesystem daemon Date: Wed, 06 Mar 2019 23:07:50 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Many People X-Bugzilla-Who: asomers@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Mar 2019 23:07:53 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D236340 Bug ID: 236340 Summary: [FUSE] fuse(4) should pass through O_APPEND to the filesystem daemon Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: asomers@FreeBSD.org Currently when you open a fuse-backed file with O_APPEND, the kernel hides = the O_APPEND flag from the fuse filesystem and computes write offsets in fuse_write_directbackend. However, that behavior doesn't work for networked fuse filesystems. The problem is that two clients both writing to the same file with O_APPEND wouldn't cooperate to update the file size. Or to put it another way, implementing O_APPEND in-kernel requires cacheing the file size attribute, and cacheing attributes is not generally allowed for networked f= ile systems. The libfuse documentation makes it explicit that filesystems must handle the O_APPEND flag as of protocol 7.23. Implicitly, filesystems should handle i= t on older protocols as well. There are two possible approaches we could take: 1) Pass O_APPEND to FUSE_OPEN and set the offset of all FUSE_WRITE operatio= ns to 0 2) Pass O_APPEND to FUSE_OPEN but still compute the offset of all FUSE_WRITE operations as we do currently, expecting that compliant fuse filesystems wi= ll ignore it. I don't know how many fuse filesystems correctly handle O_APPEND, but I bet it's less than all of them. --=20 You are receiving this mail because: You are the assignee for the bug.=