MFC r345839, r345894, r345897, r345900-r345901, r345976, r346220, r348602, r348767, r348967,
r349047-r349048, r351204-r351205, r351502, r351623, r352364, r356249-r356250, r356313,
r356434, r356628-r356629, r356636, r356657, r357421, r357716, r360359, r360428:

r345839: Assert that q can't be NULL. 'empty' is always non-NULL when DIREMPTY
r345894: Restore the ability of checking and fixing next free
r345897: Restore lfcl when LOSTDIR's chain was corrupted and overwritten
r345900: Implement checking of `.' and `..' entries of subdirectory.
r345901: Fix build.
r345976: Write string constant differently to improve readability.
r346220: Don't cast result from malloc().
r348602: Don't increment cl after increment.
r348767: preen should work independently with alwaysyes and alwaysno.
r348967: Avoid out of boundary access when checking invalid long filenames.
r349047: Blankspace. No actual code change.
r349048: In ask(): override default option if any of alwaysyes/alwaysno/rdonly is
r351204: Remove redundant check and wrong fix: fat.c checks already take care
r351205: Use calloc().
r351502: Comment boot block checks and perform additional sanity checks:
r351623: Remove unneeded blank line. No functional change.
r352364: Avoid mixing cluster numbers and sector numbers. Makes code more readable.
r356249: Reduce memory footprint of fsck_msdosfs.
r356250: Revert r356249 for now as it broke GCC builds.
r356313: Reduce memory footprint of fsck_msdosfs.
r356434: fsck_msdosfs.8: document -M.
r356628: Require FAT to occupy at least one sector.
r356629: Apply typo fix from NetBSD, we have already applied all NetBSD changes so
r356636: Correct off-by-two issue when determining FAT type.
r356657: Tighten FAT checks and fix off-by-one error in corner case.
r357421: Diff reduction against NetBSD, no functional change.
r357716: Use humanize_number to format available and bad space sizes.
r360359: Fix a bug with dirty file system handling.
r360428: Do not overflow when calculating file system size.

MFC r326276:

various: general 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.

No functional change intended.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Make UEFI booting of 4Kn disks work:
- convert boot1.efi to corrrectly calculate the lba for what the
media reports and convert the size based on what FreeBSD uses.
The existing code would use the 512 byte lba and convert the
size using 4K byte size.
- make fsck_msdosfs read the boot block as 4K so the read doesn't
fail on a 4Kn drive since FreeBSD will error out parition reads
of a block. Make the bpbBytesPerSec check a multiple of 512 since
it can be 512 or 4K depending on the disk. This allows fsck to
pass checking the EFI partition on a 4Kn disk.

To create the EFI file system I used:
newfs_msdos -F 32 -S 4096 -c 1 -m 0xf8 <partition>
This works for booting 512 and 4Kn disks.

Caveat is that loader.efi cannot read the 4Kn EFI partition. This isn't
critical right now since boot1.efi will read loader.efi from the ufs
partition. It looks like loader.efi can be fixed via making some of the
512 bytes reads more flexible. loader.efi doesn't have trouble reading
the ufs partition. This is probably a simple fix.

I now have FreeBSD installed on a system with 4Kn drives and tested the
same code works on 512.

MFC after: 1 week

Rename fields to match better the msdosfs headers. This work is still
incomplete as some info doesn't really belong to the structs where it is
defined.

Submitted by: Pedro F. Giffuni <giffunip tutopia com>
Reviewed by: bde
MFC after: 2 weeks

Bug fixes from NetBSD
- fix sign-compare issues.
- ANSIfy a couple of functions.
- Remove more duplicate #includes.
- Memory leak found by Coverity on NetBSD.

Submitted by: Pedro F. Giffuni <giffunip tutopia com>
Reviewed by: bde
MFC after: 2 weeks

License changes from NetBSD.
Move to 2 clause license, approved by Wolfgang Solfrank.

Submitted by: Pedro F. Giffuni <giffunip tutopia com>
MFC after: 2 weeks

Forced commit to note that my previous commit was a Darwin merge.

s/filesystem/file system/g as discussed on -developers

Add fsck_msdosfs.

Obtained from: NetBSD