From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 E0244212542; Tue, 4 Nov 2025 15:48:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762271339; cv=none; b=UHX97MBnYr+NkdLiIXxzTfE4W9WUDmtF0iKFTIdjvLLdSubm7ICJc6VNt3rCEIls8v3U7ZKOcT8NyFBFhv03C42qD/DgTqIMPbBi/8mhv6+wuCUFV0eeP7LYQq6i+n/yeKFYL7Alf3nX3xXpBCgQxnZD/EtaSbeRJ+x+4jpI0Ts= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762271339; c=relaxed/simple; bh=hY8Ln2pdGeKvcfoS37aVfLz+SXvrv5SLVpJJOfhRaZk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qpgPAriAP1rOZnM0le+YnG5UIHaktxeLAmtkjBiigDWyceeL5CaLV5JWrifik63EIIV23mf6taX5mEQj/LNWPPWUokf+3B/m4bhACg+QQVvV1PfDaNesqxO1AEH+UhWE1EkkE4ya6s5kKHu5xvGaDok8+vOO3vfIJbuK1qY9Qv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=U87h29E3; arc=none smtp.client-ip=198.137.202.133 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) header.d=infradead.org header.i=@infradead.org header.b="U87h29E3" 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=dZQ2HCceRJLZizFuCH6251L/mPW0nJ2MWcAlfjcOzYE=; b=U87h29E331Qjlh2PVdi31LPhZq 55UOWlNzHnULwVDA4fwO7/YTLr/+4P2zx6uls++EROIS6ej13VjaIFIBceskeZzGVxFXVyAGxMfeS e9WTjHQrfZpGJ8G1sAeieV1EueCSEqhXMULUgq0wPT3E89HWoERDJfypTbJrdm+DKHCgGyzYkIthT YiwPsIboZCtVB+h5MOW8TJD95N6i+ZOTV1hm4jp2dC0Ck7Kejx42YrNuyE7dG3c4K00bjp1IjMrWM v2DXbNzuTj5NNOd8BIbqiD+H3gwqhkEFtQySVZrcWxlD09pLdHAMEOmmQ2zOmAXdozXRxid29GF4b dtSVtPyQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vGJHC-0000000C88p-2g5H; Tue, 04 Nov 2025 15:48:54 +0000 Date: Tue, 4 Nov 2025 07:48:54 -0800 From: Christoph Hellwig To: Jan Kara Cc: Qu Wenruo , Christoph Hellwig , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, Askar Safin Subject: Re: [PATCH RFC 2/2] fs: fully sync all fses even for an emergency sync Message-ID: References: <7b7fd40c5fe440b633b6c0c741d96ce93eb5a89a.1762142636.git.wqu@suse.com> <414a076b-174d-414a-b629-9f396bce5538@suse.com> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Nov 04, 2025 at 01:42:14PM +0100, Jan Kara wrote: > No it is not. For ext4 if the transaction grows large we'll commit it. Also > if it gets too old (5s by default), we'll commit it. XFS will likely have > similar constraints. So data loss is limited but definitely not completely > avoided. But that never was the point of emergency sync. Yes, XFS will eventually clear the log as well. But the important part is that writeback of any kind will actually log the metadata changes.