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[bug #61606] Grub should support ext2/ext4 file systes with the large_di
From: |
Theodore Tso |
Subject: |
[bug #61606] Grub should support ext2/ext4 file systes with the large_dir feature |
Date: |
Thu, 2 Dec 2021 20:11:14 -0500 (EST) |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0 |
URL:
<https://savannah.gnu.org/bugs/?61606>
Summary: Grub should support ext2/ext4 file systes with the
large_dir feature
Project: GNU GRUB
Submitted by: tytso
Submitted on: Fri 03 Dec 2021 01:11:12 AM UTC
Category: Filesystem
Severity: Major
Priority: 5 - Normal
Item Group: Feature Request
Status: None
Privacy: Public
Assigned to: None
Originator Name:
Originator Email: tytso@mit.edu
Open/Closed: Open
Release:
Release: Git master
Discussion Lock: Any
Reproducibility: Every Time
Planned Release: None
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Details:
Grub uses the fs/ext2.c code to support ext2/ext3/ext4 file systems.
Recently, ext4 added the a large_dir feature, which adds support for a 3 level
htree directory support. Grub supports existing file systems with htree
directories by ignoring their existence, and since the index nodes for the
hash tree look like deleted directory entries (by design), grub can simply do
a brute force O(n) linear search of directories. The same is true for 3
level deep htrees indicated by large_dir feature flag. Hence, all that is
needed for grub to support large_dir file systems is to add the following
definition to grub-core/fs/ext2.c:
#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000 /* >2GB or 3-lvl htree */
And then add that bit into the macro EXT2_DRIVER_SUPPORT_INCOMPAT.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Fri 03 Dec 2021 01:11:12 AM UTC Name: diff Size: 1KiB By: tytso
<http://savannah.gnu.org/bugs/download.php?file_id=52412>
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- [bug #61606] Grub should support ext2/ext4 file systes with the large_dir feature,
Theodore Tso <=