From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=198.137.202.133 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793978406; b=Ow/DD6zbJ+OWY9wM1qvu+k1ZJCA2njERi/K1wcV+9pp+j54+9E9qm2NcLqabn/yYsTjk QXoOCyVSwwWVxHqOhtJ0KJzNHyfYSY1jtSRuiCj3dOJWJvqeyUBz7uQyCFzdxLx7DsAK8 CrOiT5CBB6zOYk+VpVA90gh1nKXh6Y2dmgxq6itMr4AU1gB0fOJt4U2ua7hexytvizAWm txjoF2IkLlAlvsH+ytl/pO6+VvCnl1qh9R4eeEUkLKKkvC0uxvWYGEXq4XaH8Zwr7nD9w rt+0ZxsZEjUnlEFEKMgprZwUXaDiZwY2Agk1NOZDRwFnFiXNRSdmpq4zHD9foCwp76Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793978406; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To:X-SRS-Rewrite; bh=JlkehWuvNeAqUDDm0lW60pJ1rm2Tezb4uxm9g5ZPK2Y=; b=xLdpzsD5Uqea/HNT4PhMc90Y7BYOSSNxltARc2M3TmMKNzeskIWXGYxk7s9ygM5VAUP4 Wciaf6OeV60PLJ5IPbY7ZVbxuyEZtizfhk6BLVwI1V9OGtPXqhL6vOEh84LzCTzK8THKL vpK3nPaLe8M2nUnkC6rdJ3c8p0lstsXCG9KmJMzBKEDjvQxAK8J/EiU7c/IlCbirFmusF IKQ9/AMScB1KunDDLxbiQpCSc4RZH+ccICzeNdiDie7t8tmC3z6r9NzI9YBCn7fMggqKI 1Zf2K7IvfTKpI6E4SxZiNxagLy4pRSseYnn4jeFPtFCt5E6/w8dyMhmqNainYDJ+bEQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=NleT4fbb; arc=none smtp.remote-ip=198.137.202.133 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4990606D82E; Fri, 6 Nov 2026 15:20:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org A4990606D82E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=NleT4fbb DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=JlkehWuvNeAqUDDm0lW60pJ1rm2Tezb4uxm9g5ZPK2Y=; b=NleT4fbbVCJtudoFYZQqx17+Kf qd8Dc4Tc5df3T/fufqZLn3arNky3pqfHKNX4gU1542rMqcTSbnhgjtItY9/iKDq8gu8urp2Ld+uiZ SHK2ntWU681pUotk4L9ieyug3skM46z9FEVeDJI/aHEyd4CEvF6Slyc4Itx9vasM2g9klOjqRhJpR A/pQKubHyqxD/KMMQod7PRSePZ4sKRjLjFnmok19kaackjreaOgt0cOl6+H8XIZY0DnqRoqMdoF5g 4YkQDM5x4jDU8rdyCu0A+O1NVDr+n9g8yXmtEWPI+X7/mmiQxl0LOvhKL8PkJwrm5Sh4/0iVspOpY Hb5ns+9w==; Received: from hch by bombadil.infradead.org with local (Exim 4.100.1 #2 (Red Hat Linux)) id 1xPLjY-0000000Cnlc-0PHR; Fri, 06 Nov 2026 15:20:04 +0000 Date: Fri, 6 Nov 2026 07:20:04 -0800 From: Christoph Hellwig To: Lauri Gates Cc: Dave Chinner , linux-xfs@vger.kernel.org, Carlos Maiolino , Christian Brauner , linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, ocfs2-devel@lists.linux.dev, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org Subject: Re: Concurrent FIEMAP on reflinked files serialises on the AGF buffer lock Message-ID: References: <20261106122355.16885-1-lauri.gates@gmail.com> X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261106122355.16885-1-lauri.gates@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Fri, Nov 06, 2026 at 02:23:55PM +0200, Lauri Gates wrote: > Mirroring XFS_DIFLAG2_REFLINK, the flag would mean "may have shared > extents", which is all a du tool needs to decide whether to look > closer. If it helps, I can write the patch. Please do. The main question are: - do we want it in fileattr_get or as a STATX_ATTR_ in statx. - how do we make the query reliable, and do we even need to? Besides xfs, btrfs and ocfs2 also support reflinks, and nfs (and maybe cifs?) can export the semanics remotely. So we really need a way to indicate if the file system could support reflinks to start with, and then one that the file could, so we probably need two bits