From: Rob Landley <rob@landley.net>
To: Roberto Sassu <roberto.sassu@huawei.com>,
Jim Baxter <jim_baxter@mentor.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: "hpa@zytor.com" <hpa@zytor.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Mimi Zohar <zohar@linux.ibm.com>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"initramfs@vger.kernel.org" <initramfs@vger.kernel.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"bug-cpio@gnu.org" <bug-cpio@gnu.org>,
"zohar@linux.vnet.ibm.com" <zohar@linux.vnet.ibm.com>,
Silviu Vlasceanu <Silviu.Vlasceanu@huawei.com>,
Dmitry Kasatkin <dmitry.kasatkin@huawei.com>,
"takondra@cisco.com" <takondra@cisco.com>,
"kamensky@cisco.com" <kamensky@cisco.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"james.w.mcmechan@gmail.com" <james.w.mcmechan@gmail.com>,
"linux-kbuild@vger.kernel.org" <linux-kbuild@vger.kernel.org>,
Dirk Behme <dirk.behme@de.bosch.com>,
Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk
Date: Tue, 19 Jul 2022 09:14:39 -0500 [thread overview]
Message-ID: <3d77db23-51da-be5e-b40d-a92aeb568833@landley.net> (raw)
In-Reply-To: <5b8b0bcac01b477eaa777ceb8c109f58@huawei.com>
On 7/19/22 07:26, Roberto Sassu wrote:
>> P.P.S. If you want to run a command other than /init out of initramfs or initrd,
>> use the rdinit=/run/this option. Note the root= overmount mechanism is
>> completely different code and uses the init=/run/this argument instead, which
>> means nothing to initramfs. Again, specifying root= says we are NOT staying in
>> initramfs.
>
> Sorry, it was some time ago. I have to go back and see why we needed
> a separate option.
Did I mention that init/do_mounts.c already has:
__setup("rootfstype=", fs_names_setup);
static char * __initdata root_fs_names;
static int __init fs_names_setup(char *str)
{
root_fs_names = str;
return 1;
}
void __init init_rootfs(void)
{
if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
(!root_fs_names || strstr(root_fs_names, "tmpfs")))
is_tmpfs = true;
}
I thought I'd dealt with this back in commit 6e19eded3684? Hmmm, looks like it
might need something like:
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 7058e14ad5f7..4b4e1ffa20e1 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -665,7 +665,7 @@ struct file_system_type rootfs_fs_type = {
void __init init_rootfs(void)
{
- if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
- (!root_fs_names || strstr(root_fs_names, "tmpfs")))
+ if (IS_ENABLED(CONFIG_TMPFS) && (!root_fs_names ? !saved_root_name[0] :
+ strstr(root_fs_names, "tmpfs"))
is_tmpfs = true;
}
> Maybe omitting root= was impacting on mounting
> the real root filesystem. Will get that information.
I know some old bootloaders hardwire in the command line so people can't
_remove_ the root=.
The reason I didn't just make rootfs always be tmpfs when CONFIG_TMPFS is
enabled is:
A) It uses very slightly more resources, and the common case is overmounting an
empty rootfs. (And then hiding it from /proc/mounts so people don't ask too many
questions.)
B) Some embedded systems use more than 50% of the system's memory for initramfs
contents, which the tmpfs defaults won't allow (fills up at 50%), and I'm not
sure I ever hooked up I don't think I ever hooked up rootflags= ala
root_mount_data to the initramfs mount? (If so, setting size= through that
should work...)
> Intuitively, given that root= is consumed for example by dracut, it seems
> a safer choice to have an option to explicitly choose the desired filesystem.
Sounds like a dracut issue. Have you used dracut in a system running from initramfs?
Lots of systems running from initramfs already DON'T have a root=, so you're
saying dracut being broken when there is no root= is something to work around
rather than fix in dracut, even though it's been easy to create a system without
a root= for a decade and a half already...
> Roberto
Rob
next prev parent reply other threads:[~2022-07-19 14:23 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 12:18 [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk Roberto Sassu
2019-05-23 12:18 ` [PATCH v4 1/3] initramfs: add file metadata Roberto Sassu
2022-06-15 17:54 ` Eugeniu Rosca
2019-05-23 12:18 ` [PATCH v4 2/3] initramfs: read metadata from special file METADATA!!! Roberto Sassu
2019-07-01 12:54 ` Mimi Zohar
2019-05-23 12:18 ` [PATCH v4 3/3] gen_init_cpio: add support for file metadata Roberto Sassu
2019-06-30 15:27 ` Mimi Zohar
2022-06-16 14:47 ` Eugeniu Rosca
2022-06-16 15:16 ` Eugeniu Rosca
2022-06-30 15:06 ` Roberto Sassu
2022-06-30 20:38 ` Eugeniu Rosca
2019-06-03 9:31 ` [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk Roberto Sassu
2019-06-03 18:32 ` Rob Landley
2019-06-26 8:15 ` Roberto Sassu
2019-06-30 15:39 ` Mimi Zohar
2019-07-01 13:42 ` Roberto Sassu
2019-07-01 14:31 ` Mimi Zohar
2019-07-15 16:54 ` Roberto Sassu
2019-07-24 15:34 ` Roberto Sassu
2022-06-09 10:26 ` Eugeniu Rosca
2022-06-09 11:05 ` Roberto Sassu
2022-06-10 15:33 ` Eugeniu Rosca
2022-06-10 15:38 ` Roberto Sassu
2022-06-15 9:27 ` Eugeniu Rosca
2022-07-18 16:36 ` Jim Baxter
2022-07-18 16:49 ` Roberto Sassu
2022-07-18 18:08 ` Jim Baxter
2022-07-19 6:55 ` Roberto Sassu
2022-07-19 11:50 ` Rob Landley
2022-07-19 12:26 ` Roberto Sassu
2022-07-19 14:14 ` Rob Landley [this message]
2022-07-20 11:52 ` Roberto Sassu
2022-07-29 10:37 ` Jim Baxter
2022-07-30 9:39 ` Rob Landley
2022-07-19 11:33 ` Rob Landley
2022-07-19 11:00 ` Rob Landley
2019-07-01 13:22 ` Mimi Zohar
2022-06-15 15:50 ` Alexander Lobakin
2022-06-15 16:03 ` Roberto Sassu
2022-06-16 13:24 ` Eugeniu Rosca
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