Second try; this time with a doc-update, and the ability to remount normally.
Tested against 2.6.23.
---
This patch introduces a rootdir kernel boot parameter, which specifies the
path to the kernel sys_chroot boot dir.
This is useful for systems that have more than one distribution installed on
the same fs/partition.
Cc: H. Peter Anvin <[EMAIL PROTECTED]>
Cc: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Al Boldi <[EMAIL PROTECTED]>
---
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1506,6 +1506,10 @@ and is between 256 and 4096 characters.
Useful for devices that are detected asynchronously
(e.g. USB and MMC devices).
+ rootdir= [KNL] Set root dir to chroot to on bootup.
+ Useful for systems that have more than one distribution
+ installed on the same filesystem.
+
rw [KNL] Mount root device read-write on boot
S [KNL] Run init in single mode
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -252,6 +252,16 @@ __setup("rootflags=", root_data_setup);
__setup("rootfstype=", fs_names_setup);
__setup("rootdelay=", root_delay_setup);
+static char __initdata root_dir[128];
+static int __init root_dir_setup(char *str)
+{
+ strcpy(root_dir, "./");
+ strlcat(root_dir, str, sizeof(root_dir));
+ return 1;
+}
+
+__setup("rootdir=", root_dir_setup);
+
static void __init get_fs_names(char *page)
{
char *s = page;
@@ -469,6 +479,12 @@ void __init prepare_namespace(void)
mount_root();
out:
sys_mount(".", "/", NULL, MS_MOVE, NULL);
+
+ if (root_dir) {
+ sys_mount(root_dir, root_dir, NULL, MS_BIND, NULL);
+ sys_chdir(root_dir);
+ }
+
sys_chroot(".");
security_sb_post_mountroot();
}
-
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