* [PATCH] Introduce a recovery= command line option.
@ 2015-12-03 6:35 Janne Karhunen
2015-12-14 9:08 ` Janne Karhunen
0 siblings, 1 reply; 2+ messages in thread
From: Janne Karhunen @ 2015-12-03 6:35 UTC (permalink / raw)
To: linux-mm; +Cc: Janne Karhunen
Recovery option can be used to define a secondary rootfs
in case mounting of the primary root fails. While it has
been possible to solve the issue via bootloader and/or
initrd means, this solution is suitable for systems that
want to stay bootloader agnostic and operate without an
initrd.
Signed-off-by: Janne Karhunen <Janne.Karhunen@gmail.com>
---
Documentation/kernel-parameters.txt | 3 ++
init/do_mounts.c | 64 +++++++++++++++++++++++++++++--------
2 files changed, 54 insertions(+), 13 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 742f69d..0d65a63 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3390,6 +3390,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nocompress Don't compress/decompress hibernation images.
no Disable hibernation and resume.
+ recovery= [KNL] Recovery root filesystem. This partition is attempted as
+ root in case default root filesystem does not mount.
+
retain_initrd [RAM] Keep initrd memory after extraction
rfkill.default_state=
diff --git a/init/do_mounts.c b/init/do_mounts.c
index dea5de9..994b2e5 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -39,8 +39,11 @@ int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
int root_mountflags = MS_RDONLY | MS_SILENT;
static char * __initdata root_device_name;
+static char * __initdata recovery_device_name;
static char __initdata saved_root_name[64];
+static char __initdata saved_recovery_name[64];
static int root_wait;
+static int recovery_attempt;
dev_t ROOT_DEV;
@@ -298,6 +301,15 @@ static int __init root_dev_setup(char *line)
__setup("root=", root_dev_setup);
+static int __init recovery_setup(char *line)
+{
+ strlcpy(saved_recovery_name, line, sizeof(saved_recovery_name));
+ recovery_attempt = 1;
+ return 1;
+}
+
+__setup("recovery=", recovery_setup);
+
static int __init rootwait_setup(char *str)
{
if (*str)
@@ -384,6 +396,7 @@ void __init mount_block_root(char *name, int flags)
__GFP_NOTRACK_FALSE_POSITIVE);
char *fs_names = page_address(page);
char *p;
+ int err;
#ifdef CONFIG_BLOCK
char b[BDEVNAME_SIZE];
#else
@@ -393,7 +406,7 @@ void __init mount_block_root(char *name, int flags)
get_fs_names(fs_names);
retry:
for (p = fs_names; *p; p += strlen(p)+1) {
- int err = do_mount_root(name, p, flags, root_mount_data);
+ err = do_mount_root(name, p, flags, root_mount_data);
switch (err) {
case 0:
goto out;
@@ -401,7 +414,33 @@ retry:
case -EINVAL:
continue;
}
- /*
+ if (!(flags & MS_RDONLY)) {
+ pr_warn("Retrying rootfs mount as read-only.\n");
+ flags |= MS_RDONLY;
+ goto retry;
+ }
+ if (recovery_device_name && recovery_attempt) {
+ recovery_attempt = 0;
+
+ ROOT_DEV = name_to_dev_t(recovery_device_name);
+ if (strncmp(recovery_device_name, "/dev/", 5) == 0)
+ recovery_device_name += 5;
+
+ pr_warn("Unable to mount rootfs at %s, error %d.\n",
+ root_device_name, err);
+ pr_warn("Attempting %s for recovery as requested.\n",
+ recovery_device_name);
+
+ err = create_dev("/dev/root", ROOT_DEV);
+ if (err < 0)
+ pr_emerg("Failed to re-create /dev/root: %d\n",
+ err);
+
+ root_device_name = recovery_device_name;
+ goto retry;
+ }
+
+ /*
* Allow the user to distinguish between failed sys_open
* and bad superblock on root device.
* and give them a list of the available devices
@@ -409,28 +448,24 @@ retry:
#ifdef CONFIG_BLOCK
__bdevname(ROOT_DEV, b);
#endif
- printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
+ pr_emerg("VFS: Cannot open root device \"%s\" or %s: error %d\n",
root_device_name, b, err);
- printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
+ pr_emerg("Please append a correct \"root=\" boot option; here are the available partitions:\n");
printk_all_partitions();
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
- printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
+ pr_emerg("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
"explicit textual name for \"root=\" boot option.\n");
#endif
panic("VFS: Unable to mount root fs on %s", b);
}
- if (!(flags & MS_RDONLY)) {
- flags |= MS_RDONLY;
- goto retry;
- }
- printk("List of all partitions:\n");
+ pr_emerg("List of all partitions:\n");
printk_all_partitions();
- printk("No filesystem could mount root, tried: ");
+ pr_emerg("No filesystem could mount root, tried: ");
for (p = fs_names; *p; p += strlen(p)+1)
- printk(" %s", p);
- printk("\n");
+ pr_emerg(" %s", p);
+ pr_emerg("\n");
#ifdef CONFIG_BLOCK
__bdevname(ROOT_DEV, b);
#endif
@@ -567,6 +602,9 @@ void __init prepare_namespace(void)
md_run_setup();
+ if (saved_recovery_name[0])
+ recovery_device_name = saved_recovery_name;
+
if (saved_root_name[0]) {
root_device_name = saved_root_name;
if (!strncmp(root_device_name, "mtd", 3) ||
--
1.9.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] Introduce a recovery= command line option.
2015-12-03 6:35 [PATCH] Introduce a recovery= command line option Janne Karhunen
@ 2015-12-14 9:08 ` Janne Karhunen
0 siblings, 0 replies; 2+ messages in thread
From: Janne Karhunen @ 2015-12-14 9:08 UTC (permalink / raw)
To: linux-mm; +Cc: Janne Karhunen, akpm
[-- Attachment #1: Type: text/plain, Size: 6767 bytes --]
Hi,
Any comments on this? It would help my life considerably as I have to deal
with multiple bootloaders and royally hate initrds.
--
Janne
On Thu, Dec 3, 2015 at 8:35 AM, Janne Karhunen <Janne.Karhunen@gmail.com>
wrote:
> Recovery option can be used to define a secondary rootfs
> in case mounting of the primary root fails. While it has
> been possible to solve the issue via bootloader and/or
> initrd means, this solution is suitable for systems that
> want to stay bootloader agnostic and operate without an
> initrd.
>
> Signed-off-by: Janne Karhunen <Janne.Karhunen@gmail.com>
> ---
> Documentation/kernel-parameters.txt | 3 ++
> init/do_mounts.c | 64
> +++++++++++++++++++++++++++++--------
> 2 files changed, 54 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt
> b/Documentation/kernel-parameters.txt
> index 742f69d..0d65a63 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -3390,6 +3390,9 @@ bytes respectively. Such letter suffixes can also be
> entirely omitted.
> nocompress Don't compress/decompress hibernation
> images.
> no Disable hibernation and resume.
>
> + recovery= [KNL] Recovery root filesystem. This partition is
> attempted as
> + root in case default root filesystem does not
> mount.
> +
> retain_initrd [RAM] Keep initrd memory after extraction
>
> rfkill.default_state=
> diff --git a/init/do_mounts.c b/init/do_mounts.c
> index dea5de9..994b2e5 100644
> --- a/init/do_mounts.c
> +++ b/init/do_mounts.c
> @@ -39,8 +39,11 @@ int __initdata rd_doload; /* 1 = load RAM disk, 0 =
> don't load */
>
> int root_mountflags = MS_RDONLY | MS_SILENT;
> static char * __initdata root_device_name;
> +static char * __initdata recovery_device_name;
> static char __initdata saved_root_name[64];
> +static char __initdata saved_recovery_name[64];
> static int root_wait;
> +static int recovery_attempt;
>
> dev_t ROOT_DEV;
>
> @@ -298,6 +301,15 @@ static int __init root_dev_setup(char *line)
>
> __setup("root=", root_dev_setup);
>
> +static int __init recovery_setup(char *line)
> +{
> + strlcpy(saved_recovery_name, line, sizeof(saved_recovery_name));
> + recovery_attempt = 1;
> + return 1;
> +}
> +
> +__setup("recovery=", recovery_setup);
> +
> static int __init rootwait_setup(char *str)
> {
> if (*str)
> @@ -384,6 +396,7 @@ void __init mount_block_root(char *name, int flags)
> __GFP_NOTRACK_FALSE_POSITIVE);
> char *fs_names = page_address(page);
> char *p;
> + int err;
> #ifdef CONFIG_BLOCK
> char b[BDEVNAME_SIZE];
> #else
> @@ -393,7 +406,7 @@ void __init mount_block_root(char *name, int flags)
> get_fs_names(fs_names);
> retry:
> for (p = fs_names; *p; p += strlen(p)+1) {
> - int err = do_mount_root(name, p, flags, root_mount_data);
> + err = do_mount_root(name, p, flags, root_mount_data);
> switch (err) {
> case 0:
> goto out;
> @@ -401,7 +414,33 @@ retry:
> case -EINVAL:
> continue;
> }
> - /*
> + if (!(flags & MS_RDONLY)) {
> + pr_warn("Retrying rootfs mount as read-only.\n");
> + flags |= MS_RDONLY;
> + goto retry;
> + }
> + if (recovery_device_name && recovery_attempt) {
> + recovery_attempt = 0;
> +
> + ROOT_DEV = name_to_dev_t(recovery_device_name);
> + if (strncmp(recovery_device_name, "/dev/", 5) == 0)
> + recovery_device_name += 5;
> +
> + pr_warn("Unable to mount rootfs at %s, error
> %d.\n",
> + root_device_name, err);
> + pr_warn("Attempting %s for recovery as
> requested.\n",
> + recovery_device_name);
> +
> + err = create_dev("/dev/root", ROOT_DEV);
> + if (err < 0)
> + pr_emerg("Failed to re-create /dev/root:
> %d\n",
> + err);
> +
> + root_device_name = recovery_device_name;
> + goto retry;
> + }
> +
> + /*
> * Allow the user to distinguish between failed sys_open
> * and bad superblock on root device.
> * and give them a list of the available devices
> @@ -409,28 +448,24 @@ retry:
> #ifdef CONFIG_BLOCK
> __bdevname(ROOT_DEV, b);
> #endif
> - printk("VFS: Cannot open root device \"%s\" or %s: error
> %d\n",
> + pr_emerg("VFS: Cannot open root device \"%s\" or %s: error
> %d\n",
> root_device_name, b, err);
> - printk("Please append a correct \"root=\" boot option;
> here are the available partitions:\n");
> + pr_emerg("Please append a correct \"root=\" boot option;
> here are the available partitions:\n");
>
> printk_all_partitions();
> #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
> - printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to
> specify "
> + pr_emerg("DEBUG_BLOCK_EXT_DEVT is enabled, you need to
> specify "
> "explicit textual name for \"root=\" boot
> option.\n");
> #endif
> panic("VFS: Unable to mount root fs on %s", b);
> }
> - if (!(flags & MS_RDONLY)) {
> - flags |= MS_RDONLY;
> - goto retry;
> - }
>
> - printk("List of all partitions:\n");
> + pr_emerg("List of all partitions:\n");
> printk_all_partitions();
> - printk("No filesystem could mount root, tried: ");
> + pr_emerg("No filesystem could mount root, tried: ");
> for (p = fs_names; *p; p += strlen(p)+1)
> - printk(" %s", p);
> - printk("\n");
> + pr_emerg(" %s", p);
> + pr_emerg("\n");
> #ifdef CONFIG_BLOCK
> __bdevname(ROOT_DEV, b);
> #endif
> @@ -567,6 +602,9 @@ void __init prepare_namespace(void)
>
> md_run_setup();
>
> + if (saved_recovery_name[0])
> + recovery_device_name = saved_recovery_name;
> +
> if (saved_root_name[0]) {
> root_device_name = saved_root_name;
> if (!strncmp(root_device_name, "mtd", 3) ||
> --
> 1.9.1
>
>
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2015-12-03 6:35 [PATCH] Introduce a recovery= command line option Janne Karhunen
2015-12-14 9:08 ` Janne Karhunen
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