From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 B25BE1519B0 for ; Mon, 24 Feb 2025 14:14:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740406489; cv=none; b=kH+yWrpbvmLlsEWafCnTFwQRdHZYt8R1Mx7h8PfvxWIhcahdbRttJJs7BXm+qkK1MgRx8kgaaOzUtSZ5N3DaaRg08Nm/Wvjp9WsEOpSPzgDa4cSCklOB4vYeP9Wget5LorxkMtQNY0Uc2ztT+0TRzraP+qrcKQXHMoBeexTljE4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740406489; c=relaxed/simple; bh=3JhP7BB3nypZVkURIeOoX2Pp0nUBLgGSUvan1MN+cxY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oNVRE1SJFkauxSIiB98Kx+B0sXLQ86nuZWkUoeysF8xbkDwPbmBM8mB4XeV2jdG3akNQNdBD+awGtxvjp/2/9AVUWem525exoT0oxfvVp6Q48qTWAyyvLYq7GJXzgt1/TEnE3epz3cD3ldfQz4K8lwJfpSwZJMM+uVWZar0ZI9A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=ftlTK7Fo; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="ftlTK7Fo" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VUkHUqtZBxfAfUGKyXLDWDKHo3ll9G/6glAvmQT2iRY=; b=ftlTK7FoGMtHNjJOLtobg/BoR1 1qsASk3wvtR3J2DyYfX//twhxuHRIo8nSsvSlp5nNZeuGw6y8CCWEtR7vIHGSkzL36GWnwbhRympM /HCPreIxD4k8GoNlokRekbBxG1uBfpd9WgGHW79yDNRhEyB9PJo2c35gUX0BW7Gm+566p7ND8Favm nVfet4o5Tc5c8N+WoYrhr1zmsX+m7lfkEAVEiOffgj1z6yWjV6BaOy/jYi7/tfKRHgArCLRjlJJC+ mRqgBp+GsEvwihUviO1elSYvJTKL2mxOsJFMxmXDRvTNZ4XEM52UgVrbV9DHtyZWtyM6Bjz/KWPH5 ++4T6p1g==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98 #2 (Red Hat Linux)) id 1tmZEK-000000072oe-2iwv; Mon, 24 Feb 2025 14:14:44 +0000 Date: Mon, 24 Feb 2025 14:14:44 +0000 From: Al Viro To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, Linus Torvalds , Neil Brown , Miklos Szeredi , Jan Kara Subject: Re: [RFC] dentry->d_flags locking Message-ID: <20250224141444.GX1977892@ZenIV> References: <20250224010624.GT1977892@ZenIV> <20250224013844.GU1977892@ZenIV> <20250224-attribut-singen-e29c9a49ee56@brauner> 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: <20250224-attribut-singen-e29c9a49ee56@brauner> Sender: Al Viro On Mon, Feb 24, 2025 at 11:35:47AM +0100, Christian Brauner wrote: > I think it would be worthwhile to mark dentries of such filesystems as > always unhashed and then add an assert into fs/dcache.c whenever such a > dentry should suddenly become hashed. > > That would not just make it very easy to see for the reviewer that the > dentries of this filesystem are always unhashed it would also make it > possible to spot bugs. Not sure that's useful, really... Details are tied into the tree-in-dcache rework, and I'll need to finish resurrecting that; should post in a week or so. For this series, see viro/vfs.git#work.dcache - it's a WIP at the moment, and it's going to get reordered (if nothing else, d_alloc_parallel() side needs an audit of tree-walkers to prove that it won't get confused by seeing DCACHE_PAR_LOOKUP on the stuff that hasn't yet reached in-lookup hash chains, and that might add prereqs that would need to go early in queue), but that at least fleshes out what I described upthread. I'll post individual patches for review in a few hours.