From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794302171; b=XBo0ztfDUDzzRBZnGPJTv3mVeNJav+NltBtqFPDKLxUmmkZ2KwQdgr5MEi6HsvKYfhdW Lfep2b/0DDYjQEGynV9y/V50chfu1A/bmJKd6E/q8lQWaOgm49Z0KEHZk/dBIb5mVLjxD MeAEO6dFt/a41Z55JVWcFuiy23xVtJQClq3u1WkFe4Tx54jngpTb2mNwDEb+gwTUdh+/v z4Qmwi2OyFsmUp534LGZ9m/BW2x45ZUN+M/oJynLeLlsfcFVWob0WKVLS6Iuvz36DuNuW iaKsyv2FFHfgGBeEPLjX5kGmg28wlp1c1iWbKj6Vh6FP//wB44mXYRBcSPBe90GjPjg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794302171; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=48wS641dZNlMgTbgKHYJJRZjCIIpBYSCk6vN7nPVst0=; b=DR+dwbHrptfZhTChU9EVE8BOBIF54/7M6fH5dqWSjfGkYUWpK5s/rzjy6iJd74c3+dv2 o4VXtAj9jziof5IoWK0n3LgOr7vX7cChgiwkj5osckXe6R/V6sio3GShjTlOcVEsUqHQJ 3cA0JYkMkAz+5gsvZK1vcdOH/lk+M8l7esCrhIeA4IxH0PMAvmlHXRTeAq8QHYxJO2bOX wyt61hQQjHWekiCq1D+4CM+yvAucApRPOYRfTzLizJirt+Kcvv51T6xrBTxnY6J0c4AkX 551Y42Ab7LDAhwTRGRVmL+ddcV35eWxQOJLz3B8JHh20exlxApu5yIt4Ka8pNwrlaZA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=B3k5bbEA; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93CFE606A325; Tue, 10 Nov 2026 09:16:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=B3k5bbEA Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF7381F0089F; Tue, 10 Nov 2026 09:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794302171; bh=48wS641dZNlMgTbgKHYJJRZjCIIpBYSCk6vN7nPVst0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=B3k5bbEAWfpJtZp1vzeXux0KzrY0ieZxwUJi/83P+f7eKHCKBYc9mkYVfNK2b/51Z IE7odp0lQqQ7mwusK6pgB1WlHVkO/UlsckyLpTfE8Yp89sMOk+QjYT1he8sjTHJobl zbSxv5PQZ8XY+Ts/6iaugpn66hCj3rJCosVRpDg0+EuqU7+TpcsCN1TcwITx1L6QCL 1C6NNljvCVnJ+dNekIZ/1LCG3UXVW6y81kv+eHD0umTjqyrBp3lV94BaeU5UIyHZKc zDKybfsspnrP1qhiqd+dsnxznVfYXFvZSeoRYSBElTyxocH2QJC3b5d8zXbtpIhziF ygU0pzxGVue5w== From: Christian Brauner Date: Tue, 10 Nov 2026 10:14:18 +0100 Subject: [PATCH RFC 02/41] nvmet: check that the file backend supports ->{read,write}_iter X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-work-loop-pseudo-v1-2-4c998976c6c7@kernel.org> References: <20261110-work-loop-pseudo-v1-0-4c998976c6c7@kernel.org> In-Reply-To: <20261110-work-loop-pseudo-v1-0-4c998976c6c7@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Jann Horn , Chris Mason , Josef Bacik , Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Alexander Viro , Jan Kara , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, driver-core@lists.linux.dev, linux-mm@kvack.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, apparmor@lists.ubuntu.com, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, fuse-devel@lists.linux.dev, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org, ocfs2-devel@lists.linux.dev, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-usb@vger.kernel.org, Amir Goldstein , linux-erofs@lists.ozlabs.org, linux-kselftest@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-ce4c1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1206; i=brauner@kernel.org; h=from:subject:message-id; bh=9rTO3vQgbbKMLgtf9DhInii/7oHGTrugRkWUh4dwMMs=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWR9ejBtltmGmxnek3mf9QvZzp8xjWWx5Y+Awzls7lyHP /4+2Dk3oqOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAivzwZGU4478oq2RB1Nuut 48Jj7Tu4n8+545UyJdpwumO4VdS2g7kM/9TW5p9ep3/AsD+mInRXw3I+rR/SC0xnPXVmN7wifGZ vBB8A X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 The file backend calls ->read_iter() and ->write_iter() of the backing file directly but never checks that they exist. Everything that isn't a block device ends up in the file backend. So a namespace pointing to a file without them calls a NULL pointer on its first I/O. Only buffered_io=1 gets that far as the O_DIRECT open fails for such files. Refuse them when the namespace is enabled the same way zloop does since commit 0c10f8a1a7ae ("zloop: check that the zone backing file support ->{read,write}_iter"). Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support") Signed-off-by: Christian Brauner (Amutable) --- drivers/nvme/target/io-cmd-file.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c index 695963dd932e..dfa8aa46188c 100644 --- a/drivers/nvme/target/io-cmd-file.c +++ b/drivers/nvme/target/io-cmd-file.c @@ -47,6 +47,11 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns) return ret; } + if (!ns->file->f_op->read_iter || !ns->file->f_op->write_iter) { + ret = -EINVAL; + goto err; + } + nvmet_file_ns_revalidate(ns); /* -- 2.53.0