sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Split the dir_index and dir_nlink features.

Do not allow to create more that EXT4_LINK_MAX links to directory in case
if the dir_nlink is not set, like it is done in the fresh e2fsprogs updates.

MFC after: 3 months

Add metadata_csum feature support.

Reviewed by: pfg (mentor)
Approved by: pfg (mentor)
MFC after: 6 months

Differential Revision: https://reviews.freebsd.org/D13810

sys/fs: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

ext2fs: add dir_nlink feature support.

ext4 on linux has always supported more than 32000 directories through
the dir_nlink feature, but FreeBSD was unable to catch up on this feature.
As part of the 64 bit inode changes nlink_t has been extended and this
feature is now possible.

Submitted by: Fedor Uporov
Differential Revision: https://reviews.freebsd.org/D11210

style(9) cleanups.

Just to reduce some of the issues found with indent(1).

MFC after: 1 week

ext2fs: Bring back the htree dir_index implementation.

The htree dir_index is perhaps one of the most characteristic
features of the linux ext3 implementation. It was removed
in r281670, due to repeated bug reports.

Damjan Jovanic detected and fixed three bugs and did some
stress testing by building Apache OpenOffice on top of it
so it is now in good shape to bring back.

Differential Revision: https://reviews.freebsd.org/D5007

Submitted by: Damjan Jovanovic
Reviewed by: pfg
Tested by: pho
Relnotes: Yes
MFC after: 2 months (only 10.x)

Drop experimental dir_index support.

The htree directory index is a highly desirable feature for research
purposes and was meant to improve performance in our ext2/3 driver.
Unfortunately our implementation has two problems:

- It never really delivered any performance improvement.
- It appears to corrupt the filesystem in undetermined circumstances.

Strictly speaking dir_index is not required for read/write support in
ext2/3 and our limited ext4 support still works fine without it.

Regain stability in the ext2 driver by removing it. We may need it back
(fixed) if we want to support encrypted ext4 support but thanks to the
wonders of version control we can always revert this change and bring it
back.

PR: 191895
PR: 198731
PR: 199309

MFC after: 5 days

Revert r269523:

Providing a higher EXT2_LINK_MAX limit is a bad idea for ext2/3.

Discussed with: bde

set EXT2_LINK_MAX to LINK_MAX

In linux EXT4_LINK_MAX is now 64000. We can't really do that
since i_nlink and va_nlink are signed so setting higher values
is likely to cause trouble.

This is a system limitation so set the EXT_LINK_MAX to
what the system can handle.

MFC after: 3 days

ext2fs: use of tab vs spaces.

Consistently use a single tab after a #define as mentioned in style(9).
Use tabs instead of space for indenting.
Fix a typo: "hash_vesion".

No functional change.

MFC after: 3 days

Initial implementation of the HTree directory index.

This is a port of NetBSD's GSoC 2012 Ext3 HTree directory indexing
by Vyacheslav Matyushin. It was cleaned up and enhanced for FreeBSD
by Zheng Liu (lz@).

This is an excellent example of work shared among different projects:
Vyacheslav was able to look at an early prototype from Zheng Liu who
was also able to check the code from Haiku (with permission).

As in linux, the feature is not available by default and must be
enabled explicitly with tune2fs. We still do not support the
workarounds required in readdir for NFS.

Submitted by: Zheng Liu
Tested by: Mike Ma
Sponsored by: Google Inc.
MFC after: 1 week

More ext2fs header cleanups:

- Set MAXMNTLEN nearer to where it is used.
- Move EXT2_LINK_MAX to ext2_dir.h .

MFC after: 3 days

ext2fs: general cleanup.

- Remove unused extern declarations in fs.h
- Correct comments in ext2_dir.h
- Several panic() messages showed wrong function names.
- Remove commented out stray line in ext2_alloc.c.
- Remove the unused macro EXT2_BLOCK_SIZE_BITS() and the then
write-only member e2fs_blocksize_bits from struct m_ext2fs.
- Remove the unused macro EXT2_FIRST_INO() and the then write-only
member e2fs_first_inode from struct m_ext2fs.
- Remove EXT2_DESC_PER_BLOCK() and the member e2fs_descpb from
struct m_ext2fs.
- Remove the unused members e2fs_bmask, e2fs_dbpg and
e2fs_mount_opt from struct m_ext2fs
- Correct harmless off-by-one error for fspath in ext2_vfsops.c.
- Remove the unused and broken macros EXT2_ADDR_PER_BLOCK_BITS()
and EXT2_DESC_PER_BLOCK_BITS().
- Remove the !_KERNEL versions of the EXT2_* macros.

Submitted by: Christoph Mallon
MFC after: 2 weeks

Clean some 'svn:executable' properties in the tree.

Submitted by: Christoph Mallon
MFC after: 3 days

Various style fixes including using uint*_t instead of u_int*_t.

Submitted by: Pedro F. Giffuni giffunip at yahoo

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Bring in the ext2fs work done by Aditya Sarawgi during and after Google Summer
of Code 2009:

- BSDL block and inode allocation policies for ext2fs. This involves the use
FFS1 style block and inode allocation for ext2fs. Preallocation was removed
since it was GPL'd.
- Make ext2fs MPSAFE by introducing locks to per-mount datastructures.
- Fixes for kern/122047 PR.
- Various small bugfixes.
- Move out of gnu/ directory.

Sponsored by: Google Inc.
Submitted by: Aditya Sarawgi <sarawgi.aditya AT SPAMFREE gmail DOT com>