__ __ __ __ _____ _ _ _____ _ _ _ | \/ | \ \ / / | __ \ (_) | | / ____| | | | | | \ / |_ __\ V / | |__) | __ ___ ____ _| |_ ___ | (___ | |__ ___| | | | |\/| | '__|> < | ___/ '__| \ \ / / _` | __/ _ \ \___ \| '_ \ / _ \ | | | | | | |_ / . \ | | | | | |\ V / (_| | || __/ ____) | | | | __/ | | |_| |_|_(_)_/ \_\ |_| |_| |_| \_/ \__,_|\__\___| |_____/|_| |_|\___V 2.1 if you need WebShell for Seo everyday contact me on Telegram Telegram Address : @jackleetFor_More_Tools:
<!DOCTYPE html>
<html lang="en" data-content_root="../../">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<title>1. About this Book — The Linux Kernel documentation</title>
<link rel="stylesheet" type="text/css" href="../../_static/pygments.css?v=fa44fd50" />
<link rel="stylesheet" type="text/css" href="../../_static/alabaster.css?v=3918102e" />
<script src="../../_static/documentation_options.js?v=5929fcd5"></script>
<script src="../../_static/doctools.js?v=9bcbadda"></script>
<script src="../../_static/sphinx_highlight.js?v=dc90522c"></script>
<link rel="index" title="Index" href="../../genindex.html" />
<link rel="search" title="Search" href="../../search.html" />
<link rel="next" title="2. High Level Design" href="overview.html" />
<link rel="prev" title="ext4 Data Structures and Algorithms" href="index.html" />
<link rel="stylesheet" href="../../_static/custom.css" type="text/css" />
</head><body>
<div class="document">
<div class="sphinxsidebar" role="navigation" aria-label="Main">
<div class="sphinxsidebarwrapper">
<p class="logo"><a href="../../index.html">
<img class="logo" src="../../_static/logo.svg" alt="Logo of The Linux Kernel"/>
</a></p>
<h1 class="logo"><a href="../../index.html">The Linux Kernel</a></h1>
<p class="blurb">6.18.50</p>
<search id="searchbox" style="display: none" role="search">
<h3 id="searchlabel">Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="../../search.html" method="get">
<input type="text" name="q" aria-labelledby="searchlabel" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"/>
<input type="submit" value="Go" />
</form>
</div>
</search>
<script>document.getElementById('searchbox').style.display = "block"</script>
<p>
<h3 class="kernel-toc-contents">Contents</h3>
<input type="checkbox" class="kernel-toc-toggle" id = "kernel-toc-toggle" checked>
<label class="kernel-toc-title" for="kernel-toc-toggle"></label>
<div class="kerneltoc" id="kerneltoc">
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../process/development-process.html">Development process</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../process/submitting-patches.html">Submitting patches</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../process/code-of-conduct.html">Code of conduct</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../maintainer/index.html">Maintainer handbook</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../process/index.html">All development-process docs</a></li>
</ul>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="../../core-api/index.html">Core API</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../driver-api/index.html">Driver APIs</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="../../subsystem-apis.html">Subsystems</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="../../subsystem-apis.html#core-subsystems">Core subsystems</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../subsystem-apis.html#human-interfaces">Human interfaces</a></li>
<li class="toctree-l2"><a class="reference internal" href="../../subsystem-apis.html#networking-interfaces">Networking interfaces</a></li>
<li class="toctree-l2 current"><a class="reference internal" href="../../subsystem-apis.html#storage-interfaces">Storage interfaces</a><ul class="current">
<li class="toctree-l3 current"><a class="reference internal" href="../index.html">Filesystems in the Linux kernel</a></li>
<li class="toctree-l3"><a class="reference internal" href="../../block/index.html">Block</a></li>
<li class="toctree-l3"><a class="reference internal" href="../../cdrom/index.html">CD-ROM</a></li>
<li class="toctree-l3"><a class="reference internal" href="../../scsi/index.html">SCSI Subsystem</a></li>
<li class="toctree-l3"><a class="reference internal" href="../../target/index.html">TCM Virtual Device</a></li>
<li class="toctree-l3"><a class="reference internal" href="../../nvme/index.html">NVMe Subsystem</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="../../subsystem-apis.html#other-subsystems">Other subsystems</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../../locking/index.html">Locking</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../process/license-rules.html">Licensing rules</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../doc-guide/index.html">Writing documentation</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../dev-tools/index.html">Development tools</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../dev-tools/testing-overview.html">Testing guide</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../kernel-hacking/index.html">Hacking guide</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../trace/index.html">Tracing</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../fault-injection/index.html">Fault injection</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../livepatch/index.html">Livepatching</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../rust/index.html">Rust</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../admin-guide/index.html">Administration</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../kbuild/index.html">Build system</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../admin-guide/reporting-issues.html">Reporting issues</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../tools/index.html">Userspace tools</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../userspace-api/index.html">Userspace API</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../firmware-guide/index.html">Firmware</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../devicetree/index.html">Firmware and Devicetree</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../arch/index.html">CPU architectures</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../staging/index.html">Unsorted documentation</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../translations/index.html">Translations</a></li>
</ul>
</div>
<script type="text/javascript"> <!--
var sbar = document.getElementsByClassName("sphinxsidebar")[0];
let currents = document.getElementsByClassName("current")
if (currents.length) {
sbar.scrollTop = currents[currents.length - 1].offsetTop;
}
--> </script>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../../_sources/filesystems/ext4/about.rst.txt"
rel="nofollow">Show Source</a></li>
</ul>
</div>
</div>
</div>
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="about-this-book">
<h1><span class="section-number">1. </span>About this Book<a class="headerlink" href="#about-this-book" title="Link to this heading">¶</a></h1>
<p>This document attempts to describe the on-disk format for ext4
filesystems. The same general ideas should apply to ext2/3 filesystems
as well, though they do not support all the features that ext4 supports,
and the fields will be shorter.</p>
<p><strong>NOTE</strong>: This is a work in progress, based on notes that the author
(djwong) made while picking apart a filesystem by hand. The data
structure definitions should be current as of Linux 4.18 and
e2fsprogs-1.44. All comments and corrections are welcome, since there is
undoubtedly plenty of lore that might not be reflected in freshly
created demonstration filesystems.</p>
<section id="license">
<h2><span class="section-number">1.1. </span>License<a class="headerlink" href="#license" title="Link to this heading">¶</a></h2>
<p>This book is licensed under the terms of the GNU Public License, v2.</p>
</section>
<section id="terminology">
<h2><span class="section-number">1.2. </span>Terminology<a class="headerlink" href="#terminology" title="Link to this heading">¶</a></h2>
<p>ext4 divides a storage device into an array of logical blocks both to
reduce bookkeeping overhead and to increase throughput by forcing larger
transfer sizes. Generally, the block size will be 4KiB (the same size as
pages on x86 and the block layer’s default block size), though the
actual size is calculated as 2 ^ (10 + <code class="docutils literal notranslate"><span class="pre">sb.s_log_block_size</span></code>) bytes.
Throughout this document, disk locations are given in terms of these
logical blocks, not raw LBAs, and not 1024-byte blocks. For the sake of
convenience, the logical block size will be referred to as
<code class="docutils literal notranslate"><span class="pre">$block_size</span></code> throughout the rest of the document.</p>
<p>When referenced in <code class="docutils literal notranslate"><span class="pre">preformatted</span> <span class="pre">text</span></code> blocks, <code class="docutils literal notranslate"><span class="pre">sb</span></code> refers to fields
in the super block, and <code class="docutils literal notranslate"><span class="pre">inode</span></code> refers to fields in an inode table
entry.</p>
</section>
<section id="other-references">
<h2><span class="section-number">1.3. </span>Other References<a class="headerlink" href="#other-references" title="Link to this heading">¶</a></h2>
<p>Also see <a class="reference external" href="https://www.nongnu.org/ext2-doc/">https://www.nongnu.org/ext2-doc/</a> for quite a collection of
information about ext2/3. Here’s another old reference:
<a class="reference external" href="http://wiki.osdev.org/Ext2">http://wiki.osdev.org/Ext2</a></p>
</section>
</section>
</div>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="footer">
©The kernel development community.
|
Powered by <a href="https://www.sphinx-doc.org/">Sphinx 8.1.3</a>
& <a href="https://alabaster.readthedocs.io">Alabaster 0.7.16</a>
|
<a href="../../_sources/filesystems/ext4/about.rst.txt"
rel="nofollow">Page source</a>
</div>
</body>
</html>| Name | Type | Size | Permission | Actions |
|---|---|---|---|---|
| about.html | File | 10.74 KB | 0644 |
|
| allocators.html | File | 11.32 KB | 0644 |
|
| atomic_writes.html | File | 23.38 KB | 0644 |
|
| attributes.html | File | 17.68 KB | 0644 |
|
| bigalloc.html | File | 9.84 KB | 0644 |
|
| bitmaps.html | File | 9.17 KB | 0644 |
|
| blockgroup.html | File | 16.02 KB | 0644 |
|
| blockmap.html | File | 10.92 KB | 0644 |
|
| blocks.html | File | 13.03 KB | 0644 |
|
| checksums.html | File | 11.76 KB | 0644 |
|
| directory.html | File | 30.85 KB | 0644 |
|
| dynamic.html | File | 10.05 KB | 0644 |
|
| eainode.html | File | 9.04 KB | 0644 |
|
| globals.html | File | 10.3 KB | 0644 |
|
| group_descr.html | File | 15.66 KB | 0644 |
|
| ifork.html | File | 23.04 KB | 0644 |
|
| index.html | File | 11.11 KB | 0644 |
|
| inlinedata.html | File | 10.18 KB | 0644 |
|
| inode_table.html | File | 8.43 KB | 0644 |
|
| inodes.html | File | 37.98 KB | 0644 |
|
| journal.html | File | 45.16 KB | 0644 |
|
| mmp.html | File | 11.48 KB | 0644 |
|
| orphan.html | File | 10.48 KB | 0644 |
|
| overview.html | File | 12.11 KB | 0644 |
|
| special_inodes.html | File | 10.42 KB | 0644 |
|
| super.html | File | 44.31 KB | 0644 |
|
| verity.html | File | 10.07 KB | 0644 |
|