From patchwork Mon May 20 17:36:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kaiser X-Patchwork-Id: 13668519 Received: from akranes.kaiser.cx (akranes.kaiser.cx [152.53.16.207]) (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 21C07A2D; Mon, 20 May 2024 17:37:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=152.53.16.207 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716226651; cv=none; b=poeB9tytCLRAKRoP8PMnb4L2qRRITVGCINOb992O87db2tW/QWyc8vtFC9l9xpdhrbPl2f0shg7uLMl5BsyytS1wW74/WxVYGZ38PQtSEz9jykC3dL1+12BvW2oS4ifpVqfqDjFpZUwf8WW+gN/+NASWm8iFdNJf477vgOa0JzA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716226651; c=relaxed/simple; bh=3pJWOpeUaIw55Dq1/uPdfsrzR6sFZhwannbYrrdZqUk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=P0tGO8hqjvPlPaN1Fgu6VogU+2AMjBxkVV3tZT+Ih7oXHRYOR9neKEAZIWR3chlLNIpXtNROtzojuJYFbm5gqJpKL+Pjb3lgWOe6hsn0fb0YYN4wKjQQT7EoCMClWkE6tgreBQh2JOOcq+XLNG7qWcK84iyJRDmg/cNK8fyhKuE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kaiser.cx; spf=pass smtp.mailfrom=kaiser.cx; arc=none smtp.client-ip=152.53.16.207 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kaiser.cx Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kaiser.cx Received: from dslb-084-059-234-031.084.059.pools.vodafone-ip.de ([84.59.234.31] helo=martin-debian-3.kaiser.cx) by akranes.kaiser.cx with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1s96wY-000hxD-2p; Mon, 20 May 2024 19:37:02 +0200 From: Martin Kaiser To: Anna Schumaker , Trond Myklebust , David Howells Cc: NeilBrown , Jeff Layton , Josef Bacik , Chuck Lever , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Kaiser Subject: [PATCH v4] nfs: keep server info for remounts Date: Mon, 20 May 2024 19:36:39 +0200 Message-Id: <20240520173639.174439-1-martin@kaiser.cx> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 With newer kernels that use fs_context for nfs mounts, remounts fail with -EINVAL. $ mount -t nfs -o nolock 10.0.0.1:/tmp/test /mnt/test/ $ mount -t nfs -o remount /mnt/test/ mount: mounting 10.0.0.1:/tmp/test on /mnt/test failed: Invalid argument For remounts, the nfs server address and port are populated by nfs_init_fs_context and later overwritten with 0x00 bytes by nfs23_parse_monolithic. The remount then fails as the server address is invalid. Fix this by not overwriting nfs server info in nfs23_parse_monolithic if we're doing a remount. Fixes: f2aedb713c28 ("NFS: Add fs_context support.") Signed-off-by: Martin Kaiser --- v4: - rebased against linux-next from 20th May 2024 v3: - rebased against linux-next from 12th April 2024 v2: - rebased against linux-next from 26th February 2024 Dear all, I'm resending this patch again. The problem that I'm trying to fix is still present in today's linux-next. It affects (amongst others) systems where the rootfs is mounted via nfs2/3. If the rootfs is mounted read-only first and remounted read-write later, the remount will fail and the system won't boot. Thanks in advance for any reviews and comments. I guess that we're taking this path for remounts do_remount fs_context_for_reconfigure alloc_fs_context init_fs_context == nfs_init_fs_context fc->root is set for remounts ctx->nfs_server is populated parse_monolithic_mount_data nfs_fs_context_parse_monolithic nfs23_parse_monolithic ctx->nfs_server is overwritten with data from mount request An alternative to checking for !is_remount_fc(fc) would be to check if (ctx->nfs_server.addrlen == 0) fs/nfs/fs_context.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c index d0a0956f8a13..cac1157be2c2 100644 --- a/fs/nfs/fs_context.c +++ b/fs/nfs/fs_context.c @@ -1112,9 +1112,12 @@ static int nfs23_parse_monolithic(struct fs_context *fc, ctx->acdirmax = data->acdirmax; ctx->need_mount = false; - memcpy(sap, &data->addr, sizeof(data->addr)); - ctx->nfs_server.addrlen = sizeof(data->addr); - ctx->nfs_server.port = ntohs(data->addr.sin_port); + if (!is_remount_fc(fc)) { + memcpy(sap, &data->addr, sizeof(data->addr)); + ctx->nfs_server.addrlen = sizeof(data->addr); + ctx->nfs_server.port = ntohs(data->addr.sin_port); + } + if (sap->ss_family != AF_INET || !nfs_verify_server_address(sap)) goto out_no_address;