From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 7D845187B for ; Sat, 16 Dec 2023 01:06:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="uftjT5jG" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:In-Reply-To:References; bh=JRzv9TUa+PNLva3DsR7EBE5y5Uie+bx4+iivXY7GV6k=; b=uftjT5jGU43CQOr3Y8HMh0uR6L KTuTi7L2r5sbTOk4xoAuJZ0N5qOZx8QBzJjXTPAT46uWnbvOSb+UCzPTStScuQLquhlpYvhvH68n3 a4ZlTjatb8p3p/HxlX1bXMG0iFXmPy7185iN5UsCGbh6eyxcL8z3wy/LtPSSFIAX4AV/k8Q1WLhvR KFnin9GYPq8qndlnoy9WQf0N9biNMAPAjRHEWhcxxV3TCJWDcTcgZE+hHfNIqHlblo+exLFe2NmGE trUyEUJFwwpCUerKNPV2ihtayQn5e8e2We9XMEeoEP9BRzbhOsiqlMusfH5CfpHT4Sko2e0QMMST3 g7Sbnl2A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1rEJ7u-0054wM-No; Sat, 16 Dec 2023 01:05:58 +0000 Date: Sat, 16 Dec 2023 01:05:58 +0000 From: Matthew Wilcox To: Miklos Szeredi Cc: linux-fsdevel@vger.kernel.org Subject: Why doesn't FUSE use stable writes? Message-ID: Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline I'm looking at fuse_writepage_locked() and it allocates a new page, then copies from the page cache into that page before sending that page to userspace. I imagine you want to prevent torn writes, so why not set SB_I_STABLE_WRITES instead of having this memcpy?