From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935443AbXGMTBA (ORCPT ); Fri, 13 Jul 2007 15:01:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S937057AbXGMTAp (ORCPT ); Fri, 13 Jul 2007 15:00:45 -0400 Received: from moutng.kundenserver.de ([212.227.126.183]:62651 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937000AbXGMTAn (ORCPT ); Fri, 13 Jul 2007 15:00:43 -0400 Date: Fri, 13 Jul 2007 21:00:30 +0200 (CEST) From: Bodo Eggert <7eggert@gmx.de> To: Bodo Eggert <7eggert@gmx.de> cc: linux-kernel@vger.kernel.org Subject: [PATCH 2/3][try 1] init: enable system-on-initramfs: root-on-tmpfs In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-be10.7eggert.dyndns.org-MailScanner-Information: See www.mailscanner.info for information X-be10.7eggert.dyndns.org-MailScanner: Found to be clean X-be10.7eggert.dyndns.org-MailScanner-From: 7eggert@gmx.de X-Provags-ID: V01U2FsdGVkX18G3pV7pMLPc+QFgkSxtou+kZRSGlN+s5geDk2 Dm7ABo2ZvuWCUq+ApbeCec6yMgHreRUiKZi2GQJTX5ZrgbZRN2 o/Ll5D4dxm5FzS63JvF/w== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Change the root filesystem to tmpfs. Doing this makes having a system on tmpfs much easier, while allowing to discard the now unnecessary ramfs. Having the rootfs on tmpfs allows to safely run e.g. a rescue system without using tricks. You might even include the rescue system into the kernel. This is a rework of Al Boldi's "[PATCH] initramfs: Allow rootfs to use tmpfs instead of ramfs". All the fame belongs to him, the bugs belong to me. Signed-Off-By: Bodo Eggert <7eggert@gmx.de> diff -Xdontdiff -pruN linux-2.6.22.base/fs/Kconfig linux-2.6.22.tmpfsroot/fs/Kconfig --- linux-2.6.22.base/fs/Kconfig 2007-07-12 14:05:16.000000000 +0200 +++ linux-2.6.22.tmpfsroot/fs/Kconfig 2007-07-12 15:10:09.000000000 +0200 @@ -989,6 +989,22 @@ config TMPFS_POSIX_ACL If you don't know what Access Control Lists are, say N. +config TMPFS_ROOT + bool "Use tmpfs instrad of ramfs for initramfs" + depends on TMPFS + default n + help + This replaces the ramfs used for unpacking the cpio images + with tmpfs, thereby allowing swapping these contents to disk and + adding size limit support. + + Side effect: + This is useful only if you don't plan on mounting a different + root filesystem. Therefore it will change the default of the + root= parameter to "rootfs". + + If unsure, say N + config HUGETLBFS bool "HugeTLB file system support" depends on X86 || IA64 || PPC64 || SPARC64 || SUPERH || BROKEN @@ -1003,7 +1019,7 @@ config HUGETLB_PAGE def_bool HUGETLBFS config RAMFS - bool + bool "Ramfs file system support" if TMPFS_ROOT default y ---help--- Ramfs is a file system which keeps all files in RAM. It allows diff -Xdontdiff -pruN linux-2.6.22.base/fs/ramfs/inode.c linux-2.6.22.tmpfsroot/fs/ramfs/inode.c --- linux-2.6.22.base/fs/ramfs/inode.c 2007-07-12 14:05:17.000000000 +0200 +++ linux-2.6.22.tmpfsroot/fs/ramfs/inode.c 2007-07-12 15:01:32.000000000 +0200 @@ -189,6 +189,13 @@ int ramfs_get_sb(struct file_system_type return get_sb_nodev(fs_type, flags, data, ramfs_fill_super, mnt); } +static struct file_system_type ramfs_fs_type = { + .name = "ramfs", + .get_sb = ramfs_get_sb, + .kill_sb = kill_litter_super, +}; + +#ifdef CONFIG_RAMFS_ROOTFS static int rootfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { @@ -196,17 +203,18 @@ static int rootfs_get_sb(struct file_sys mnt); } -static struct file_system_type ramfs_fs_type = { - .name = "ramfs", - .get_sb = ramfs_get_sb, - .kill_sb = kill_litter_super, -}; static struct file_system_type rootfs_fs_type = { .name = "rootfs", .get_sb = rootfs_get_sb, .kill_sb = kill_litter_super, }; +int __init init_rootfs(void) +{ + return register_filesystem(&rootfs_fs_type); +} +#endif + static int __init init_ramfs_fs(void) { return register_filesystem(&ramfs_fs_type); @@ -220,9 +228,4 @@ static void __exit exit_ramfs_fs(void) module_init(init_ramfs_fs) module_exit(exit_ramfs_fs) -int __init init_rootfs(void) -{ - return register_filesystem(&rootfs_fs_type); -} - MODULE_LICENSE("GPL"); diff -Xdontdiff -pruN linux-2.6.22.base/init/do_mounts.c linux-2.6.22.tmpfsroot/init/do_mounts.c --- linux-2.6.22.base/init/do_mounts.c 2007-07-12 15:04:48.000000000 +0200 +++ linux-2.6.22.tmpfsroot/init/do_mounts.c 2007-07-12 14:53:07.000000000 +0200 @@ -24,7 +24,11 @@ int __initdata rd_doload; /* 1 = load RA int root_mountflags = MS_RDONLY | MS_SILENT; char * __initdata root_device_name; +#ifdef CONFIG_TMPFS_ROOT +static char __initdata saved_root_name[64] = "rootfs"; +#else static char __initdata saved_root_name[64]; +#endif dev_t ROOT_DEV; diff -Xdontdiff -pruN linux-2.6.22.base/mm/shmem.c linux-2.6.22.tmpfsroot/mm/shmem.c --- linux-2.6.22.base/mm/shmem.c 2007-07-12 14:05:25.000000000 +0200 +++ linux-2.6.22.tmpfsroot/mm/shmem.c 2007-07-12 15:01:32.000000000 +0200 @@ -2369,6 +2369,8 @@ static void init_once(void *foo, struct static int init_inodecache(void) { + if (shmem_inode_cachep) + return 0; shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), 0, 0, init_once, NULL); @@ -2582,6 +2584,34 @@ put_memory: return ERR_PTR(error); } +#ifdef CONFIG_TMPFS_ROOT +static int rootfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) +{ + return get_sb_nodev(fs_type, flags|MS_NOUSER, data, shmem_fill_super, + mnt); +} + +/*static struct super_block *rootfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return get_sb_single(fs_type, flags, data, shmem_fill_super); +}*/ + +static struct file_system_type rootfs_fs_type = { + .name = "rootfs", + .get_sb = rootfs_get_sb, + .kill_sb = kill_litter_super, +}; + +int __init init_rootfs(void) +{ + if (init_inodecache()) + panic("Can't initialize shm inode cache"); + return register_filesystem(&rootfs_fs_type); +} +#endif + /* * shmem_zero_setup - setup a shared anonymous mapping *