From patchwork Mon Jan 17 13:43:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: CGEL X-Patchwork-Id: 12715433 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85E5DC433F5 for ; Mon, 17 Jan 2022 13:44:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233875AbiAQNoS (ORCPT ); Mon, 17 Jan 2022 08:44:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233849AbiAQNoR (ORCPT ); Mon, 17 Jan 2022 08:44:17 -0500 Received: from mail-qt1-x833.google.com (mail-qt1-x833.google.com [IPv6:2607:f8b0:4864:20::833]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCB3DC06161C; Mon, 17 Jan 2022 05:44:16 -0800 (PST) Received: by mail-qt1-x833.google.com with SMTP id y17so19176680qtx.9; Mon, 17 Jan 2022 05:44:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=DXdJ1Wu64slVHJ1cuUusc0RVIkVBLrraxvrfe/fkEAc=; b=PBYzj9/f5BfD87HuXENKRr4lCmln39PPI1X8u1+hoDdGbYkv02jO+YFPHp4Mm+3Eip YMoMJzlDNp2Di5yLDVEpomX688I8CF8YrWTwh3WyW48nXt+dkupEXk+vS1WrdY2Ezc8f sDDnY/pEA/l06PIjoFP44G26k7p3F7ZXP1TcNxJTWZQAIB6YmbpBTdQY7cgjrPwnCmey I1CGXRWUrQW4FEq9DXOG38Syqe8mtZPSdTP+GbDuIEleY03G0tcwMCG1jlvBSS4taQAP r+HKcqKiLccjmsYva346xf2XCNgq6y+T1mKGnTNBqhIZi/FOm26I3IbfQHWcmVnXSOy5 nomA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=DXdJ1Wu64slVHJ1cuUusc0RVIkVBLrraxvrfe/fkEAc=; b=5lCiswHNRUEg/OSZbAUxVwjOyF2DTFxOutxYlrrylVTAd4t3T6VQzltoEq1sBWECeR QTA2lUIX/4zSvh7aSF4zmyzsGnQDSnOdZnztXHtFqmgF5dqTwuSvAXuhAsRo6RX7tOko fmGmFVBvhSwFWfWLHTkccji5gN6cQkdO+IsN0kNo+Cp99iuMAodL26683YfA0OTaQWiv 2fCYRC5wOhz6cNgj6S4SRPHkrFnhKDHdLfy/7tS1KjSsaUOIZSOOqBxl/vNfMT7oMgXx zt8vHml8yn5pYZ8pfLzHkRr+Rshfg6cGSocl4l9WqTSUcVilMArFOiIQZ3kVQdfX/qmD rmRw== X-Gm-Message-State: AOAM5310NoCr1Us2//MBoNmpqXdtKuMfTN1QATfQpXtEUw8zf9Mf2g2p /zUIuUSoKbebfuClUExDtcE= X-Google-Smtp-Source: ABdhPJwW56XhB17V4FOfsibHf7gI3R9NsaIBYqJc14q+k44PVnI7Wc10DN080EnTikhRXdOwmTBESA== X-Received: by 2002:a05:622a:15c9:: with SMTP id d9mr5759731qty.681.1642427056076; Mon, 17 Jan 2022 05:44:16 -0800 (PST) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id s1sm9124073qtw.25.2022.01.17.05.44.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jan 2022 05:44:15 -0800 (PST) From: cgel.zte@gmail.com X-Google-Original-From: zhang.yunkai@zte.com.cn To: mhiramat@kernel.org Cc: viro@zeniv.linux.org.uk, keescook@chromium.org, samitolvanen@google.com, ojeda@kernel.org, johan@kernel.org, bhelgaas@google.com, elver@google.com, masahiroy@kernel.org, zhang.yunkai@zte.com.cn, axboe@kernel.dk, vgoyal@redhat.com, jack@suse.cz, leon@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, linux@rasmusvillemoes.dk, palmerdabbelt@google.com, f.fainelli@gmail.com, wangkefeng.wang@huawei.com, rostedt@goodmis.org, ahalaney@redhat.com, valentin.schneider@arm.com, peterz@infradead.org, geert@linux-m68k.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: [PATCH v7 1/2] init/main.c: introduce function ramdisk_exec_exist() Date: Mon, 17 Jan 2022 13:43:51 +0000 Message-Id: <20220117134352.866706-2-zhang.yunkai@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220117134352.866706-1-zhang.yunkai@zte.com.cn> References: <20220117134352.866706-1-zhang.yunkai@zte.com.cn> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Zhang Yunkai Introduce the function ramdisk_exec_exist, which is used to check the exist of 'ramdisk_execute_command'. To make path lookup follow the mount on '/', use vfs_path_lookup() in init_eaccess(), and make the filesystem that mounted on '/' as root during path lookup. Reported-by: Menglong Dong Signed-off-by: Zhang Yunkai --- fs/init.c | 11 +++++++++-- include/linux/init.h | 1 + init/main.c | 7 ++++++- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/init.c b/fs/init.c index 5c36adaa9b44..166356a1f15f 100644 --- a/fs/init.c +++ b/fs/init.c @@ -112,14 +112,21 @@ int __init init_chmod(const char *filename, umode_t mode) int __init init_eaccess(const char *filename) { - struct path path; + struct path path, root; int error; - error = kern_path(filename, LOOKUP_FOLLOW, &path); + error = kern_path("/", LOOKUP_DOWN, &root); if (error) return error; + error = vfs_path_lookup(root.dentry, root.mnt, filename, + LOOKUP_FOLLOW, &path); + if (error) + goto on_err; error = path_permission(&path, MAY_ACCESS); + path_put(&path); +on_err: + path_put(&root); return error; } diff --git a/include/linux/init.h b/include/linux/init.h index d82b4b2e1d25..889d538b6dfa 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -149,6 +149,7 @@ extern unsigned int reset_devices; void setup_arch(char **); void prepare_namespace(void); void __init init_rootfs(void); +bool ramdisk_exec_exist(void); extern struct file_system_type rootfs_fs_type; #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) diff --git a/init/main.c b/init/main.c index bb984ed79de0..ed1c63f4ed87 100644 --- a/init/main.c +++ b/init/main.c @@ -1577,6 +1577,11 @@ void __init console_on_rootfs(void) fput(file); } +bool __init ramdisk_exec_exist(void) +{ + return init_eaccess(ramdisk_execute_command) == 0; +} + static noinline void __init kernel_init_freeable(void) { /* Now the scheduler is fully set up and can do blocking allocations */ @@ -1618,7 +1623,7 @@ static noinline void __init kernel_init_freeable(void) * check if there is an early userspace init. If yes, let it do all * the work */ - if (init_eaccess(ramdisk_execute_command) != 0) { + if (!ramdisk_exec_exist()) { ramdisk_execute_command = NULL; prepare_namespace(); } From patchwork Mon Jan 17 13:43:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: CGEL X-Patchwork-Id: 12715434 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFE81C433F5 for ; Mon, 17 Jan 2022 13:44:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234183AbiAQNoa (ORCPT ); Mon, 17 Jan 2022 08:44:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234400AbiAQNo3 (ORCPT ); Mon, 17 Jan 2022 08:44:29 -0500 Received: from mail-qt1-x830.google.com (mail-qt1-x830.google.com [IPv6:2607:f8b0:4864:20::830]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FDD0C061574; Mon, 17 Jan 2022 05:44:29 -0800 (PST) Received: by mail-qt1-x830.google.com with SMTP id y10so19216745qtw.1; Mon, 17 Jan 2022 05:44:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Qsy9iO5QNpvhH9vyZT3hQoa7mdrCF0c+4JFfeVVUuQM=; b=IZyW5y1GdwVl4px0QbEDSD5Och9801oxJf/NX9GACC+pgxTDmHVKIslQUql6bJ5S6x /HSbFuxd3e+t6P5ZIBj2PQ89oXpA7aj/r6swB7g3IUlOgWPgem7G6Cq3q97sEsWymI42 4aP4JUNgPO1UepFxMEXuang0gitNPKSqOMAugWbCAyR5BTqxEs7dXy4e4WSAdg0CW2+Z becCt/znlJBnsH7Nx3IL0CoEe4M3YW9s3Qolk76ke5kGj8bue2KLiFCVI0nMuRh0q1nq HX5VnDg3Vejeeu9oyEIfT95UkOtVCHTO/V8gKE5N3IwyWZ2d6WKZj98b0/yHZRjDaqap +Xrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Qsy9iO5QNpvhH9vyZT3hQoa7mdrCF0c+4JFfeVVUuQM=; b=jbHvsflZcpCqhE/qYThi0rQXKdO9NNYe944jecfVkVt+WtcTQsXKDyfFRoRaOKi3mr 9+siUdhZAWoibPrLNMu3pKwzJBU5AkWLcqHLggH7Y7gx+qRjOMTX6wyQ0suagbiUraqD m8h2sAAVhdUmKoL6omjVAAWCkoIkeTIAH6hiSgfMDH5M+n8XTV3hX3tXvQKv5uhjyJ9T Lg7MKpq6nyI5oDbKHMEtHWnaA24YYfm3zPIUn9MEq3V2bGG9XEeIjyMgwHv7xvvyZWZG J7dh3jD9TSA4TGrIcDXkMKyrt2hh9kF0timykSG6l/7OAF5vOE5db0Sqmc6YxvpxiKmx QQzQ== X-Gm-Message-State: AOAM531Q81xa2Bmn7OHb7qYp25CvQ3CtMXxDEYSRlSpcIRAhIfiJcOKO cX+nzhRJBmSEf0rRXMIfoEA= X-Google-Smtp-Source: ABdhPJxQsWdKsWj/NjJjvb51fnkcnvopF7I1gnuJ1RN6LMTotZtbNsNDsA6oh8XfU7+xCe/MqRhwGA== X-Received: by 2002:a05:622a:512:: with SMTP id l18mr17146823qtx.120.1642427068243; Mon, 17 Jan 2022 05:44:28 -0800 (PST) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id s1sm9124073qtw.25.2022.01.17.05.44.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jan 2022 05:44:27 -0800 (PST) From: cgel.zte@gmail.com X-Google-Original-From: zhang.yunkai@zte.com.cn To: mhiramat@kernel.org Cc: viro@zeniv.linux.org.uk, keescook@chromium.org, samitolvanen@google.com, ojeda@kernel.org, johan@kernel.org, bhelgaas@google.com, elver@google.com, masahiroy@kernel.org, zhang.yunkai@zte.com.cn, axboe@kernel.dk, vgoyal@redhat.com, jack@suse.cz, leon@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, linux@rasmusvillemoes.dk, palmerdabbelt@google.com, f.fainelli@gmail.com, wangkefeng.wang@huawei.com, rostedt@goodmis.org, ahalaney@redhat.com, valentin.schneider@arm.com, peterz@infradead.org, geert@linux-m68k.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, dong.menglong@zte.com.cn Subject: [PATCH v7 2/2] init/do_mounts.c: create second mount for initramfs Date: Mon, 17 Jan 2022 13:43:52 +0000 Message-Id: <20220117134352.866706-3-zhang.yunkai@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220117134352.866706-1-zhang.yunkai@zte.com.cn> References: <20220117134352.866706-1-zhang.yunkai@zte.com.cn> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Zhang Yunkai If using container platforms such as Docker, upon initialization it wants to use pivot_root() so that currently mounted devices do not propagate to containers. An example of value in this is that a USB device connected prior to the creation of a containers on the host gets disconnected after a container is created; if the USB device was mounted on containers, but already removed and umounted on the host, the mount point will not go away until all containers unmount the USB device. Another reason for container platforms such as Docker to use pivot_root is that upon initialization the net-namspace is mounted under /var/run/docker/netns/ on the host by dockerd. Without pivot_root Docker must either wait to create the network namespace prior to the creation of containers or simply deal with leaking this to each container. pivot_root is supported if the rootfs is a initrd or block device, but it's not supported if the rootfs uses an initramfs (tmpfs). This means container platforms today must resort to using block devices if they want to pivot_root from the rootfs. A workaround to use chroot() is not a clean viable option given every container will have a duplicate of every mount point on the host. In order to support using container platforms such as Docker on all the supported rootfs types we must extend Linux to support pivot_root on initramfs as well. This patch does the work to do just that. pivot_root will unmount the mount of the rootfs from its parent mount and mount the new root to it. However, when it comes to initramfs, it donesn't work, because the root filesystem has not parent mount, which makes initramfs not supported by pivot_root. In order to make pivot_root supported on initramfs, we create a second mount with type of rootfs before unpacking cpio, and change root to this mount after unpacking. While mounting the second rootfs, 'rootflags' is passed, and it means that we can set options for the mount of rootfs in boot cmd now. For example, the size of tmpfs can be set with 'rootflags=size=1024M'. This patch is from: [init/initramfs.c: make initramfs support pivot_root] https://lore.kernel.org/all/20210605034447.92917-3-dong.menglong@zte.com.cn/ I fix some console bugs. Reported-by: dong.menglong@zte.com.cn Signed-off-by: Zhang Yunkai --- init/do_mounts.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ init/do_mounts.h | 17 ++++++++++++++++- init/initramfs.c | 12 +++++++++++- usr/Kconfig | 10 ++++++++++ 4 files changed, 82 insertions(+), 2 deletions(-) diff --git a/init/do_mounts.c b/init/do_mounts.c index 762b534978d9..8a72c1fe17c8 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -650,6 +650,50 @@ void __init prepare_namespace(void) } static bool is_tmpfs; +#ifdef CONFIG_INITRAMFS_MOUNT + +/* + * Give systems running from the initramfs and making use of pivot_root a + * proper mount so it can be umounted during pivot_root. + */ +int __init prepare_mount_rootfs(void) +{ + char *rootfs = "ramfs"; + + if (is_tmpfs) + rootfs = "tmpfs"; + + init_mkdir("/root", 0700); + return do_mount_root(rootfs, rootfs, + root_mountflags & ~MS_RDONLY, + root_mount_data); +} + +/* + * Revert to previous mount by chdir to '/' and unmounting the second + * mount. + */ +void __init revert_mount_rootfs(void) +{ + init_chdir("/"); + init_umount(".", MNT_DETACH); +} + +/* + * Change root to the new rootfs that mounted in prepare_mount_rootfs() + * if cpio is unpacked successfully and 'ramdisk_execute_command' exist. + */ +void __init finish_mount_rootfs(void) +{ + init_mount(".", "/", NULL, MS_MOVE, NULL); + if (likely(ramdisk_exec_exist())) + init_chroot("."); + else + revert_mount_rootfs(); +} + +#define rootfs_init_fs_context ramfs_init_fs_context +#else static int rootfs_init_fs_context(struct fs_context *fc) { if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) @@ -657,6 +701,7 @@ static int rootfs_init_fs_context(struct fs_context *fc) return ramfs_init_fs_context(fc); } +#endif struct file_system_type rootfs_fs_type = { .name = "rootfs", diff --git a/init/do_mounts.h b/init/do_mounts.h index 7a29ac3e427b..ae4ab306caa9 100644 --- a/init/do_mounts.h +++ b/init/do_mounts.h @@ -10,9 +10,24 @@ #include #include +extern int root_mountflags; + void mount_block_root(char *name, int flags); void mount_root(void); -extern int root_mountflags; + +#ifdef CONFIG_INITRAMFS_MOUNT + +int prepare_mount_rootfs(void); +void finish_mount_rootfs(void); +void revert_mount_rootfs(void); + +#else + +static inline int prepare_mount_rootfs(void) { return 0; } +static inline void finish_mount_rootfs(void) { } +static inline void revert_mount_rootfs(void) { } + +#endif static inline __init int create_dev(char *name, dev_t dev) { diff --git a/init/initramfs.c b/init/initramfs.c index 2f3d96dc3db6..881fb8ea4352 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -17,6 +17,8 @@ #include #include +#include "do_mounts.h" + static ssize_t __init xwrite(struct file *file, const char *p, size_t count, loff_t *pos) { @@ -671,7 +673,12 @@ static void __init populate_initrd_image(char *err) static void __init do_populate_rootfs(void *unused, async_cookie_t cookie) { /* Load the built in initramfs */ - char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size); + char *err; + + if (prepare_mount_rootfs()) + panic("Failed to mount rootfs\n"); + + err = unpack_to_rootfs(__initramfs_start, __initramfs_size); if (err) panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */ @@ -685,11 +692,14 @@ static void __init do_populate_rootfs(void *unused, async_cookie_t cookie) err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start); if (err) { + revert_mount_rootfs(); #ifdef CONFIG_BLK_DEV_RAM populate_initrd_image(err); #else printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err); #endif + } else { + finish_mount_rootfs(); } done: diff --git a/usr/Kconfig b/usr/Kconfig index 8bbcf699fe3b..af2aeeef8635 100644 --- a/usr/Kconfig +++ b/usr/Kconfig @@ -52,6 +52,16 @@ config INITRAMFS_ROOT_GID If you are not sure, leave it set to "0". +config INITRAMFS_MOUNT + bool "Create second mount to make pivot_root() supported" + default y + help + Before unpacking cpio, create a second mount and make it become + the root filesystem. Therefore, initramfs will be supported by + pivot_root(). + + If container platforms is used with initramfs, say Y. + config RD_GZIP bool "Support initial ramdisk/ramfs compressed using gzip" default y