Subject: [PATCH] tmpfs-root

I updated the patch from Ryan Hope <rmh3093@gmail.com> to 3.0.
---
 fs/Kconfig       |   21 +++++++++++++++++++++
 fs/Makefile      |    1 +
 fs/ramfs/inode.c |   39 +++++++++++++++++++++------------------
 mm/shmem.c       |   25 +++++++++++++++++++++++++
 4 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 19891aa..2ae154e 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -151,6 +151,27 @@ config TMPFS_XATTR
 
 	  If unsure, say N.
 
+config TMPFS_ROOT
+	bool "Use tmpfs instrad of ramfs for initramfs"
+	depends on TMPFS && SHMEM
+	default n
+	help
+	  This replaces the ramfs used for unpacking the cpio images
+	  with tmpfs.
+
+	  If unsure, say N
+
+config RAMFS
+	bool "Ramfs file system support" if TMPFS_ROOT
+	default y
+	---help---
+	  Ramfs is a file system which keeps all files in RAM. Unlike tmpfs,
+	  it cannot be swapped to disk, and it has the risk of deadlocking
+	  the system by using all memory.
+
+	  Ramfs is used for booting the system and unpacking the cpio if
+	  TMPFS_ROOT is not set.
+
 config HUGETLBFS
 	bool "HugeTLB file system support"
 	depends on X86 || IA64 || SPARC64 || (S390 && 64BIT) || \
diff --git a/fs/Makefile b/fs/Makefile
index fb68c2b..68db666 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_DLM)		+= dlm/
  
 # Do not add any filesystems before this line
 obj-$(CONFIG_FSCACHE)		+= fscache/
+obj-$(CONFIG_RAMFS)             += ramfs/
 obj-$(CONFIG_REISERFS_FS)	+= reiserfs/
 obj-$(CONFIG_EXT3_FS)		+= ext3/ # Before ext2 so root fs can be ext3
 obj-$(CONFIG_EXT2_FS)		+= ext2/
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index eacb166..c3dbf22 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -261,6 +261,13 @@ struct dentry *ramfs_mount(struct file_system_type *fs_type,
 	return mount_nodev(fs_type, flags, data, ramfs_fill_super);
 }
 
+static struct file_system_type ramfs_fs_type = {
+	.name		= "ramfs",
+	.mount		= ramfs_mount,
+	.kill_sb	= kill_litter_super,
+};
+
+#ifndef CONFIG_TMPFS_ROOT
 static struct dentry *rootfs_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
@@ -273,30 +280,12 @@ static void ramfs_kill_sb(struct super_block *sb)
 	kill_litter_super(sb);
 }
 
-static struct file_system_type ramfs_fs_type = {
-	.name		= "ramfs",
-	.mount		= ramfs_mount,
-	.kill_sb	= ramfs_kill_sb,
-};
 static struct file_system_type rootfs_fs_type = {
 	.name		= "rootfs",
 	.mount		= rootfs_mount,
 	.kill_sb	= kill_litter_super,
 };
 
-static int __init init_ramfs_fs(void)
-{
-	return register_filesystem(&ramfs_fs_type);
-}
-
-static void __exit exit_ramfs_fs(void)
-{
-	unregister_filesystem(&ramfs_fs_type);
-}
-
-module_init(init_ramfs_fs)
-module_exit(exit_ramfs_fs)
-
 int __init init_rootfs(void)
 {
 	int err;
@@ -311,5 +300,19 @@ int __init init_rootfs(void)
 
 	return err;
 }
+#endif
+
+static int __init init_ramfs_fs(void)
+{
+	return register_filesystem(&ramfs_fs_type);
+}
+
+static void __exit exit_ramfs_fs(void)
+{
+	unregister_filesystem(&ramfs_fs_type);
+}
+
+module_init(init_ramfs_fs)
+module_exit(exit_ramfs_fs)
 
 MODULE_LICENSE("GPL");
diff --git a/mm/shmem.c b/mm/shmem.c
index fcedf54..57d22f1 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2669,6 +2669,10 @@ static void init_once(void *foo)
 
 static int init_inodecache(void)
 {
+#ifdef CONFIG_TMPFS_ROOT
+	if (shmem_inode_cachep)
+		return 0;
+#endif
 	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
 				sizeof(struct shmem_inode_info),
 				0, SLAB_PANIC, init_once);
@@ -3015,6 +3019,27 @@ put_memory:
 }
 EXPORT_SYMBOL_GPL(shmem_file_setup);
 
+#ifdef CONFIG_TMPFS_ROOT
+static struct dentry *rootfs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_nodev(fs_type, flags, data, shmem_fill_super);
+}
+
+static struct file_system_type rootfs_fs_type = {
+	.name		= "rootfs",
+	.mount		= rootfs_mount,
+	.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
  * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
--