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 77D0831352A;
	Wed, 20 May 2026 08:24:32 +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=1779265474; cv=none; b=eMUAzmh4pM0AC22DCIq6P1DAKuBtVh7btsMcggoXxC3pc0C+72tpyxvaraqWsvu+tthLFK0nohvZUm3MImNVka70AC4KeeN7M5E+Ungl1TTWHTrE1lTL19NpGciVwaCf642WPe6wEmJzTr0DdofoIXzk0GxbVoY1PelpNHxbJDo=
ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org;
	s=arc-20240116; t=1779265474; c=relaxed/simple;
	bh=r+QVAPKBzwJOTRXNU1NXUQU0eVlMPxJ+ayXxO7+rfs4=;
	h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:
	 Content-Type:Content-Disposition:In-Reply-To; b=G0ULv7KnJwFduVsbTZsqwcp4c2PB/c9T+awHURXyUgJqCt2TAa7wdbOkmUlEl3S3aOfbLB3Z5XEtk/gMbz9ptJCrt3UswAoVdTdSO1QRMrR+ah3oNjQ4alwRiARfpFH14hEgn8Pkvsvb+ZxrjL40ZuBpwajURxHoktvOM4Vq5pQ=
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=C3qdrXdp; 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="C3qdrXdp"
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=6IFC3wldLeo4x/t+xYgOODr2zcH9+Jthub9CBamxD8s=; b=C3qdrXdpZzKyBGmMNMUU7S89JJ
	MyWS6UOi83XhNUvWPxMkY3G0i77aO9rB6WOUtfiDRy49OSEQHOU7lOTHID+zd/kgVcbdAhKSobMKR
	Sq+nYQZM21HsXuii1DvC18bznzCd0CtiI1vTAjKhqV1DvBwppCM86+NUIFAcKwOiWOEx7R/iJmHMO
	ErxJa2FzzkxZUS5fciBjF2DPqjEqvBgSzFMeML6U6bmHCcB3qUHw8G3chxuwFFA1DaaIejZ+p88CZ
	VeorXwqV6eHKmZcdukJQIbQam/tKpLtrByDTV7l3YT/Gh7rJu/veHRIMBAeM72z3aWK1mxQnXA1CO
	HwrDgawA==;
Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux))
	id 1wPcEC-00000003x2M-0EtP;
	Wed, 20 May 2026 08:24:32 +0000
Date: Wed, 20 May 2026 01:24:32 -0700
From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dai Ngo <dai.ngo@oracle.com>, Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <dgc@kernel.org>, cem@kernel.org,
	linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org,
	Sergey Bashirov <sergeybashirov@gmail.com>
Subject: Re: [PATCH 1/1] xfs: fix overlapping extents returned for pNFS
 LAYOUTGET
Message-ID: <ag1vwFHoYatausLK@infradead.org>
References: <06d9b1ae-e46f-459c-bcb4-1a5ca4ded4b0@oracle.com>
 <20260514002513.GQ9555@frogsfrogsfrogs>
 <26365a46-bdac-4e8a-a951-de904c3e5606@oracle.com>
 <ageSguSyf2kBY33a@dread>
 <b9860332-7b1e-448e-869a-ad59d8d5b7c0@oracle.com>
 <agqfBPRWXQDR2ImG@infradead.org>
 <606c4cea-70d2-4601-9db2-611cd35c3687@oracle.com>
 <agwDhixPAAA0-cTa@infradead.org>
 <55c7c22a-8edb-4833-be3f-1f6555ba90ed@oracle.com>
 <20260519145949.GH9555@frogsfrogsfrogs>
Precedence: bulk
X-Mailing-List: linux-xfs@vger.kernel.org
List-Id: <linux-xfs.vger.kernel.org>
List-Subscribe: <mailto:linux-xfs+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-xfs+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20260519145949.GH9555@frogsfrogsfrogs>
X-SRS-Rewrite: SMTP reverse-path rewritten from <hch@infradead.org> by bombadil.infradead.org. See http://www.infradead.org/rpr.html

[adding Sergey, who wrote the code to allow multiple mappings]

On Tue, May 19, 2026 at 07:59:49AM -0700, Darrick J. Wong wrote:
> 1) xfs_fs_map_blocks only takes i_rwsem and XFS_ILOCK; it doesn't take
> the mmap invalidation lock.  Does that mean that pagefaults could wander
> in and mess with the layout?

Looks like it.

> 2) Now that NFS apparently can serve up multiple mappings at once,
> should ->map_blocks pass in an array element count so that we can do
> multiple iomaps in a single lock cycle?

I guess we need to do that, or revert the code to provide multiple maps
for now.

> 3) Do the reflink and realtime inode checks need to be re-assessed after
> grabbing the ilock since they can change?

Yes.