From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: Linux Doc Mailing List <linux-doc@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-fsdevel@vger.kernel.org
Subject: [PATCH 34/44] docs: filesystems: convert ramfs-rootfs-initramfs.txt to ReST
Date: Mon, 17 Feb 2020 17:12:20 +0100 [thread overview]
Message-ID: <89cbcc99a6371f3bff3ea1668fe497e8a15c226b.1581955849.git.mchehab+huawei@kernel.org> (raw)
In-Reply-To: <cover.1581955849.git.mchehab+huawei@kernel.org>
- Add a SPDX header;
- Add a document title;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add table markups;
- Use notes markups;
- Add lists markups;
- Add it to filesystems/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
Documentation/filesystems/index.rst | 1 +
...itramfs.txt => ramfs-rootfs-initramfs.rst} | 54 +++++++++++--------
2 files changed, 33 insertions(+), 22 deletions(-)
rename Documentation/filesystems/{ramfs-rootfs-initramfs.txt => ramfs-rootfs-initramfs.rst} (91%)
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 08883a481a76..b8689d082911 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -83,5 +83,6 @@ Documentation for filesystem implementations.
overlayfs
proc
qnx6
+ ramfs-rootfs-initramfs
virtiofs
vfat
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.rst
similarity index 91%
rename from Documentation/filesystems/ramfs-rootfs-initramfs.txt
rename to Documentation/filesystems/ramfs-rootfs-initramfs.rst
index 97d42ccaa92d..6c576e241d86 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.rst
@@ -1,5 +1,11 @@
-ramfs, rootfs and initramfs
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
+Ramfs, rootfs and initramfs
+===========================
+
October 17, 2005
+
Rob Landley <rob@landley.net>
=============================
@@ -99,14 +105,14 @@ out of that.
All this differs from the old initrd in several ways:
- The old initrd was always a separate file, while the initramfs archive is
- linked into the linux kernel image. (The directory linux-*/usr is devoted
- to generating this archive during the build.)
+ linked into the linux kernel image. (The directory ``linux-*/usr`` is
+ devoted to generating this archive during the build.)
- The old initrd file was a gzipped filesystem image (in some file format,
such as ext2, that needed a driver built into the kernel), while the new
initramfs archive is a gzipped cpio archive (like tar only simpler,
- see cpio(1) and Documentation/driver-api/early-userspace/buffer-format.rst). The
- kernel's cpio extraction code is not only extremely small, it's also
+ see cpio(1) and Documentation/driver-api/early-userspace/buffer-format.rst).
+ The kernel's cpio extraction code is not only extremely small, it's also
__init text and data that can be discarded during the boot process.
- The program run by the old initrd (which was called /initrd, not /init) did
@@ -139,7 +145,7 @@ and living in usr/Kconfig) can be used to specify a source for the
initramfs archive, which will automatically be incorporated into the
resulting binary. This option can point to an existing gzipped cpio
archive, a directory containing files to be archived, or a text file
-specification such as the following example:
+specification such as the following example::
dir /dev 755 0 0
nod /dev/console 644 0 0 c 5 1
@@ -175,12 +181,12 @@ or extracting your own preprepared cpio files to feed to the kernel build
(instead of a config file or directory).
The following command line can extract a cpio image (either by the above script
-or by the kernel build) back into its component files:
+or by the kernel build) back into its component files::
cpio -i -d -H newc -F initramfs_data.cpio --no-absolute-filenames
The following shell script can create a prebuilt cpio archive you can
-use in place of the above config file:
+use in place of the above config file::
#!/bin/sh
@@ -202,14 +208,17 @@ use in place of the above config file:
exit 1
fi
-Note: The cpio man page contains some bad advice that will break your initramfs
-archive if you follow it. It says "A typical way to generate the list
-of filenames is with the find command; you should give find the -depth option
-to minimize problems with permissions on directories that are unwritable or not
-searchable." Don't do this when creating initramfs.cpio.gz images, it won't
-work. The Linux kernel cpio extractor won't create files in a directory that
-doesn't exist, so the directory entries must go before the files that go in
-those directories. The above script gets them in the right order.
+.. Note::
+
+ The cpio man page contains some bad advice that will break your initramfs
+ archive if you follow it. It says "A typical way to generate the list
+ of filenames is with the find command; you should give find the -depth
+ option to minimize problems with permissions on directories that are
+ unwritable or not searchable." Don't do this when creating
+ initramfs.cpio.gz images, it won't work. The Linux kernel cpio extractor
+ won't create files in a directory that doesn't exist, so the directory
+ entries must go before the files that go in those directories.
+ The above script gets them in the right order.
External initramfs images:
--------------------------
@@ -236,9 +245,10 @@ An initramfs archive is a complete self-contained root filesystem for Linux.
If you don't already understand what shared libraries, devices, and paths
you need to get a minimal root filesystem up and running, here are some
references:
-http://www.tldp.org/HOWTO/Bootdisk-HOWTO/
-http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html
-http://www.linuxfromscratch.org/lfs/view/stable/
+
+- http://www.tldp.org/HOWTO/Bootdisk-HOWTO/
+- http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html
+- http://www.linuxfromscratch.org/lfs/view/stable/
The "klibc" package (http://www.kernel.org/pub/linux/libs/klibc) is
designed to be a tiny C library to statically link early userspace
@@ -255,7 +265,7 @@ name lookups, even when otherwise statically linked.)
A good first step is to get initramfs to run a statically linked "hello world"
program as init, and test it under an emulator like qemu (www.qemu.org) or
-User Mode Linux, like so:
+User Mode Linux, like so::
cat > hello.c << EOF
#include <stdio.h>
@@ -326,8 +336,8 @@ the above threads) is:
explained his reasoning:
- http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1550.html
- http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1638.html
+ - http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1550.html
+ - http://www.uwsg.iu.edu/hypermail/linux/kernel/0112.2/1638.html
and, most importantly, designed and implemented the initramfs code.
--
2.24.1
next prev parent reply other threads:[~2020-02-17 16:12 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1581955849.git.mchehab+huawei@kernel.org>
2020-02-17 16:11 ` [PATCH 01/44] docs: filesystems: convert 9p.txt to ReST Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 02/44] docs: filesystems: convert adfs.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 03/44] docs: filesystems: convert affs.txt " Mauro Carvalho Chehab
2020-02-18 13:04 ` David Sterba
2020-02-17 16:11 ` [PATCH 04/44] docs: filesystems: convert afs.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 05/44] docs: filesystems: convert autofs-mount-control.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 06/44] docs: filesystems: convert befs.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 07/44] docs: filesystems: convert bfs.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 08/44] docs: filesystems: convert btrfs.txt " Mauro Carvalho Chehab
2020-02-17 18:50 ` David Sterba
2020-02-17 19:34 ` Jonathan Corbet
2020-02-18 11:44 ` David Sterba
2020-02-17 16:11 ` [PATCH 09/44] docs: filesystems: convert ceph.txt " Mauro Carvalho Chehab
2020-02-18 11:57 ` Jeff Layton
2020-02-17 16:11 ` [PATCH 10/44] docs: filesystems: convert cramfs.txt " Mauro Carvalho Chehab
2020-02-17 18:11 ` Nicolas Pitre
2020-02-17 16:11 ` [PATCH 11/44] docs: filesystems: convert debugfs.txt " Mauro Carvalho Chehab
2020-02-17 16:11 ` [PATCH 12/44] docs: filesystems: convert dlmfs.txt " Mauro Carvalho Chehab
2020-02-18 1:21 ` Joseph Qi
2020-02-18 10:07 ` Mauro Carvalho Chehab
2020-02-18 10:55 ` Joseph Qi
2020-02-17 16:11 ` [PATCH 13/44] docs: filesystems: convert ecryptfs.txt " Mauro Carvalho Chehab
2020-02-17 20:07 ` Tyler Hicks
2020-02-17 16:12 ` [PATCH 14/44] docs: filesystems: convert efivarfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 15/44] docs: filesystems: convert erofs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 16/44] docs: filesystems: convert ext2.txt " Mauro Carvalho Chehab
2020-02-18 7:11 ` Jan Kara
2020-02-17 16:12 ` [PATCH 17/44] docs: filesystems: convert ext3.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 18/44] docs: filesystems: convert f2fs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 19/44] docs: filesystems: convert gfs2.txt " Mauro Carvalho Chehab
2020-02-18 13:13 ` Bob Peterson
2020-02-17 16:12 ` [PATCH 20/44] docs: filesystems: convert gfs2-uevents.txt " Mauro Carvalho Chehab
2020-02-18 13:13 ` Bob Peterson
2020-02-17 16:12 ` [PATCH 21/44] docs: filesystems: convert hfsplus.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 22/44] docs: filesystems: convert hfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 23/44] docs: filesystems: convert hpfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 24/44] docs: filesystems: convert inotify.txt " Mauro Carvalho Chehab
2020-02-18 7:10 ` Jan Kara
2020-02-17 16:12 ` [PATCH 25/44] docs: filesystems: convert isofs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 26/44] docs: filesystems: convert nilfs2.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 27/44] docs: filesystems: convert ntfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 28/44] docs: filesystems: convert ocfs2-online-filecheck.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 29/44] docs: filesystems: convert ocfs2.txt " Mauro Carvalho Chehab
2020-02-18 1:23 ` Joseph Qi
2020-02-17 16:12 ` [PATCH 30/44] docs: filesystems: convert omfs.txt " Mauro Carvalho Chehab
2020-02-18 0:57 ` Bob Copeland
2020-02-17 16:12 ` [PATCH 31/44] docs: filesystems: convert orangefs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 33/44] docs: filesystems: convert qnx6.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` Mauro Carvalho Chehab [this message]
2020-02-17 16:12 ` [PATCH 35/44] docs: filesystems: convert relay.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 36/44] docs: filesystems: convert romfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 37/44] docs: filesystems: convert squashfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 38/44] docs: filesystems: convert sysfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 39/44] docs: filesystems: convert sysv-fs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 40/44] docs: filesystems: convert tmpfs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 41/44] docs: filesystems: convert ubifs-authentication.rst.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 42/44] docs: filesystems: convert ubifs.txt " Mauro Carvalho Chehab
2020-02-17 16:12 ` [PATCH 43/44] docs: filesystems: convert udf.txt " Mauro Carvalho Chehab
2020-02-18 7:12 ` Jan Kara
2020-02-18 10:13 ` Mauro Carvalho Chehab
2020-02-18 10:57 ` Jan Kara
2020-02-17 16:12 ` [PATCH 44/44] docs: filesystems: convert zonefs.txt " Mauro Carvalho Chehab
2020-02-18 3:46 ` Damien Le Moal
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