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 C185F2AD3D; Sat, 25 Oct 2025 04:45:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761367539; cv=none; b=Mlx2D466/Sob6EfOOPIXDdOnaxe+hTQGh5WT2dq4EHf+pqp9prz0fTwoDOaLCWzB3StMs/8ZFaJ4rizEPodouL9Jsh3CCNfwt49bfX60e47r+4mTkYljMYK1w1ULEI913wyy/3eFIHt/ZJp6tmK0IXknWgKSmKk8U5hw407WJTE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761367539; c=relaxed/simple; bh=MpWNGfxEaaSWJwURGuFrqvFiZNrJ2gPR2Wx/QXwoJJM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nF2nw5oJNgNO0Rka5BkFE0zFvea2fs8N9WNWsbyf0SoerphsyzbRZVbS24WHliBJXsxd+IGh8z0RtbQ4+7wWAJGLpP3MUt+ZEUp/26lcZeFkU3dvvy5I+ZzS9xaItpVzNnqtN+3g3UtSqltOIJ6yIYPHrWtcoxS8zmiDphXh5FU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=hDX9dsBt; arc=none smtp.client-ip=90.155.50.34 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="hDX9dsBt" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=mQjSkC3ua7dzjDBzte7rrQ5nRmVgH3qrTQ90wWZPPLY=; b=hDX9dsBtzcXQhmANie+AEm0YjV vQPj5MEpcoB8AwXFuNdkmltwxQ5HpiwG1cTqtkVeoePAILnF3KENpgMIAzd3/DVFo/IiirZI9Mn+0 fi0ShxIRMGcTV7vg4v0Xf15vjyffKlDO13+qyKY1LLfJp2bFl7UNyPofCg8ySrxnbDuOSo7nHmGoF 5KtjMg0mCDSzvbPwLKHm7wtbOWD1igBnB4XsrR7UGfgPsro0Y4H0KYqBKZe8U2fJ5YJlXw+OfEVJg +Y8fR+CrgkgR3dYM/4QfOjvpRU2OEwjiQKHdRtPdlth+lEdJKvXaaHiJJm3zh8SVkJ9FBxJuOaCKE K7m1Gnjg==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vCW9i-00000002hpY-0vxi; Sat, 25 Oct 2025 04:45:30 +0000 Date: Sat, 25 Oct 2025 05:45:29 +0100 From: Matthew Wilcox To: libaokun@huaweicloud.com Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, linux-kernel@vger.kernel.org, kernel@pankajraghav.com, mcgrof@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, yi.zhang@huawei.com, yangerkun@huawei.com, chengzhihao1@huawei.com, libaokun1@huawei.com Subject: Re: [PATCH 22/25] fs/buffer: prevent WARN_ON in __alloc_pages_slowpath() when BS > PS Message-ID: References: <20251025032221.2905818-1-libaokun@huaweicloud.com> <20251025032221.2905818-23-libaokun@huaweicloud.com> 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 In-Reply-To: <20251025032221.2905818-23-libaokun@huaweicloud.com> On Sat, Oct 25, 2025 at 11:22:18AM +0800, libaokun@huaweicloud.com wrote: > + while (1) { > + folio = __filemap_get_folio(mapping, index, fgp_flags, > + gfp & ~__GFP_NOFAIL); > + if (!IS_ERR(folio) || !(gfp & __GFP_NOFAIL)) > + return folio; > + > + if (PTR_ERR(folio) != -ENOMEM && PTR_ERR(folio) != -EAGAIN) > + return folio; > + > + memalloc_retry_wait(gfp); > + } No, absolutely not. We're not having open-coded GFP_NOFAIL semantics. The right way forward is for ext4 to use iomap, not for buffer heads to support large block sizes.