mirror of
https://github.com/torvalds/linux.git
synced 2024-12-20 18:11:47 +00:00
3103084afc
Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com> Link: https://lore.kernel.org/r/20220520022255.2120576-2-wangjianjian3@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
56 lines
1.3 KiB
ReStructuredText
56 lines
1.3 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
Special inodes
|
|
--------------
|
|
|
|
ext4 reserves some inode for special features, as follows:
|
|
|
|
.. list-table::
|
|
:widths: 6 70
|
|
:header-rows: 1
|
|
|
|
* - inode Number
|
|
- Purpose
|
|
* - 0
|
|
- Doesn't exist; there is no inode 0.
|
|
* - 1
|
|
- List of defective blocks.
|
|
* - 2
|
|
- Root directory.
|
|
* - 3
|
|
- User quota.
|
|
* - 4
|
|
- Group quota.
|
|
* - 5
|
|
- Boot loader.
|
|
* - 6
|
|
- Undelete directory.
|
|
* - 7
|
|
- Reserved group descriptors inode. (“resize inode”)
|
|
* - 8
|
|
- Journal inode.
|
|
* - 9
|
|
- The “exclude” inode, for snapshots(?)
|
|
* - 10
|
|
- Replica inode, used for some non-upstream feature?
|
|
* - 11
|
|
- Traditional first non-reserved inode. Usually this is the lost+found directory. See s_first_ino in the superblock.
|
|
|
|
Note that there are also some inodes allocated from non-reserved inode numbers
|
|
for other filesystem features which are not referenced from standard directory
|
|
hierarchy. These are generally reference from the superblock. They are:
|
|
|
|
.. list-table::
|
|
:widths: 20 50
|
|
:header-rows: 1
|
|
|
|
* - Superblock field
|
|
- Description
|
|
|
|
* - s_lpf_ino
|
|
- Inode number of lost+found directory.
|
|
* - s_prj_quota_inum
|
|
- Inode number of quota file tracking project quotas
|
|
* - s_orphan_file_inum
|
|
- Inode number of file tracking orphan inodes.
|