Linus, please ignore this one _only_ if you have received this message
today already -- it is identical to previous one (resending only because
of email problems)
---------- Forwarded message ----------
Date: Tue, 19 Dec 2000 09:25:08 +0000 (GMT)
From: Tigran Aivazian <[email protected]>
To: Linus Torvalds <[email protected]>
Cc: [email protected]
Subject: [patch-2.4.0-test13-pre3] rootfs (3rd attempt)
Hi Linus,
The "final" version of yesterday contained two bugs (thanks to Andreas
Dilger for spotting both of them). This version contains 0 bugs and was
very thoroughly tested (including boundary conditions etc.). Basically, it
is absolutely final, really.
the bugs were a) n < 32 should be n <= sizeof(rootfs) and b) the diff
context of the old panic msg was missing (because I hand-edited the patch
instead of remaking it).
Regards,
Tigran
diff -urN -X dontdiff linux/Documentation/kernel-parameters.txt rootfs/Documentation/kernel-parameters.txt
--- linux/Documentation/kernel-parameters.txt Tue Sep 5 21:51:14 2000
+++ rootfs/Documentation/kernel-parameters.txt Mon Dec 18 09:04:06 2000
@@ -473,7 +473,10 @@
ro [KNL] Mount root device read-only on boot.
- root= [KNL] root filesystem.
+ root= [KNL] Mount root filesystem on specified (as hex or "/dev/XXX") device.
+
+ rootfs= [KNL] Use filesystem type specified (e.g. rootfs=ext2) for root.
+
rw [KNL] Mount root device read-write on boot.
diff -urN -X dontdiff linux/fs/super.c rootfs/fs/super.c
--- linux/fs/super.c Tue Dec 12 09:25:22 2000
+++ rootfs/fs/super.c Tue Dec 19 08:16:32 2000
@@ -18,6 +18,7 @@
* Torbj?rn Lindh ([email protected]), April 14, 1996.
* Added devfs support: Richard Gooch <[email protected]>, 13-JAN-1998
* Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
+ * Added rootfs boot param. used by mount_root(): Tigran Aivazian. Dec 2000.
*/
#include <linux/config.h>
@@ -58,6 +59,12 @@
/* this is initialized in init/main.c */
kdev_t ROOT_DEV;
+/* this can be set at boot time, e.g. rootfs=ext2
+ * if set to invalid value or if read_super() fails on the specified
+ * filesystem type then mount_root() will panic
+ */
+static char rootfs[32] __initdata = "";
+
int nr_super_blocks;
int max_super_blocks = NR_SUPER;
LIST_HEAD(super_blocks);
@@ -78,6 +85,17 @@
static struct file_system_type *file_systems;
static rwlock_t file_systems_lock = RW_LOCK_UNLOCKED;
+static int __init rootfs_setup(char *line)
+{
+ int n = strlen(line) + 1;
+
+ if (n > 1 && n <= sizeof(rootfs))
+ strncpy(rootfs, line, n);
+ return 1;
+}
+
+__setup("rootfs=", rootfs_setup);
+
/* WARNING: This can be used only if we _already_ own a reference */
static void get_filesystem(struct file_system_type *fs)
{
@@ -1579,6 +1597,16 @@
goto mount_it;
}
+ if (*rootfs) {
+ fs_type = get_fs_type(rootfs);
+ if (fs_type) {
+ sb = read_super(ROOT_DEV,bdev,fs_type,root_mountflags,NULL,1);
+ if (sb)
+ goto mount_it;
+ }
+ /* don't try others if type given explicitly, same behaviour as mount(8) */
+ goto fail;
+ }
read_lock(&file_systems_lock);
for (fs_type = file_systems ; fs_type ; fs_type = fs_type->next) {
if (!(fs_type->fs_flags & FS_REQUIRES_DEV))
@@ -1593,7 +1621,8 @@
put_filesystem(fs_type);
}
read_unlock(&file_systems_lock);
- panic("VFS: Unable to mount root fs on %s", kdevname(ROOT_DEV));
+fail:
+ panic("VFS: Unable to mount root %s on %s", *rootfs ? rootfs : "fs", kdevname(ROOT_DEV));
mount_it:
printk ("VFS: Mounted root (%s filesystem)%s.\n",