MFC r328957:
{ext2|ufs}_readdir: Avoid setting negative ncookies.

ncookies cannot be negative or the allocator will fail. This should only
happen if a caller is very broken but we can still try to survive the
event.

We should probably also verify for uio_resid > MAXPHYS but in that case
it is not clear that just clipping the ncookies value is an adequate
response.

MFC r310705, r310706:
style(9) cleanups.

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

MFC r294504, r294652, r294653, r294655:

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
RelNotes: yes

MFC r281670, r281703:
Drop experimental ext2fs 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 r277354, r277365:
ext2: Garbage-collect some unused variables

Reported by: clang static analysis

MFC r275897:
Set NOCACHE flag for CREATE namei() calls, do not specially handle
MAKEENTRY in VOP_LOOKUP().

MFC r262623, r262667:

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 r260988, r261034, r261120, r261235:

ext2fs: Properly the EXT4_EXTENTS and EXT4_INDEX to the inode flags.

In order to support Ext4 extents we need to pass the Ext4 inode flags
without interfering with the chflags. This is better done by using the
i_flag field in the inode and doing proper translation to the linux
ext4 equivalents.

Solve a potential corruption issue in the dirindex code. The dirindex
code can now be renabled as the problems related to it have been
solved.

Suggested by: bde
Tested by: kevlo

MFC r281670, r281703:
Drop experimental ext2fs 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 r277354, r277365:
ext2: Garbage-collect some unused variables

Reported by: clang static analysis

MFC r275897:
Set NOCACHE flag for CREATE namei() calls, do not specially handle
MAKEENTRY in VOP_LOOKUP().

MFC r262623, r262667:

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 r260988, r261034, r261120, r261235:

ext2fs: Properly the EXT4_EXTENTS and EXT4_INDEX to the inode flags.

In order to support Ext4 extents we need to pass the Ext4 inode flags
without interfering with the chflags. This is better done by using the
i_flag field in the inode and doing proper translation to the linux
ext4 equivalents.

Solve a potential corruption issue in the dirindex code. The dirindex
code can now be renabled as the problems related to it have been
solved.

Suggested by: bde
Tested by: kevlo