Documentation/filesystems/ext2.rst

Source file repositories/reference/linux-study-clean/Documentation/filesystems/ext2.rst

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Documentation/filesystems/ext2.rst
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.rst
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Support Tooling And Documentation
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Documentation
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Support Tooling And Documentation: documentation
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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.. SPDX-License-Identifier: GPL-2.0


==============================
The Second Extended Filesystem
==============================

ext2 was originally released in January 1993.  Written by R\'emy Card,
Theodore Ts'o and Stephen Tweedie, it was a major rewrite of the
Extended Filesystem.  It is currently still (April 2001) the predominant
filesystem in use by Linux.  There are also implementations available
for NetBSD, FreeBSD, the GNU HURD, Windows 95/98/NT, OS/2 and RISC OS.

Options
=======

Most defaults are determined by the filesystem superblock, and can be
set using tune2fs(8). Kernel-determined defaults are indicated by (*).

====================    ===     ================================================
bsddf			(*)	Makes ``df`` act like BSD.
minixdf				Makes ``df`` act like Minix.

check=none, nocheck	(*)	Don't do extra checking of bitmaps on mount
				(check=normal and check=strict options removed)

dax				Use direct access (no page cache).  See
				Documentation/filesystems/dax.rst.

debug				Extra debugging information is sent to the
				kernel syslog.  Useful for developers.

errors=continue			Keep going on a filesystem error.
errors=remount-ro		Remount the filesystem read-only on an error.
errors=panic			Panic and halt the machine if an error occurs.

grpid, bsdgroups		Give objects the same group ID as their parent.
nogrpid, sysvgroups		New objects have the group ID of their creator.

nouid32				Use 16-bit UIDs and GIDs.

oldalloc			Enable the old block allocator. Orlov should
				have better performance, we'd like to get some
				feedback if it's the contrary for you.
orlov			(*)	Use the Orlov block allocator.
				(See http://lwn.net/Articles/14633/ and
				http://lwn.net/Articles/14446/.)

resuid=n			The user ID which may use the reserved blocks.
resgid=n			The group ID which may use the reserved blocks.

sb=n				Use alternate superblock at this location.

user_xattr			Enable "user." POSIX Extended Attributes
				(requires CONFIG_EXT2_FS_XATTR).
nouser_xattr			Don't support "user." extended attributes.

acl				Enable POSIX Access Control Lists support
				(requires CONFIG_EXT2_FS_POSIX_ACL).
noacl				Don't support POSIX ACLs.

quota, usrquota			Enable user disk quota support
				(requires CONFIG_QUOTA).

grpquota			Enable group disk quota support
				(requires CONFIG_QUOTA).
====================    ===     ================================================

noquota option ls silently ignored by ext2.

Annotation

Implementation Notes