MFC r305977:
Be more strict when selecting between snapshot/regular mount.

MFC r297791:
UFS: replace 0 with NULL for pointers.

While here also do late initialization of the variables we are
changing.

Found with devel/coccinelle.

Reviewed by: mckusick

MFC r297311:
Ensure that TRIMs are finished before unmount destroys ufsmount.

MFC of 269533:

Limit the number of cylinder groups that will be searched when
trying to build a cluster. The limit is tunable using the sysctl
vfs.ffs.maxclustersearch. The current limit is 10 cylinder groups
per block allocation. It was previously limited to the number of
cylinder groups in the filesystem per block allocation. When there
were no clusters of the needed size left, it repeatedly searched
the whole filesystem for a non-existent cluster on every block
allocation. The result was very slow filesystem allocation with
100% CPU utilization. The old behavior can be had by setting
vfs.ffs.maxclustersearch to a huge number (1,000,000).

This change affects only the layout policy routines so is not able
to interfere with the integrity of the filesystem.

Reported by: Dmitry Sivachenko (demon@)
Tested by: Dmitry Sivachenko (demon@)

Merge r263233 from HEAD to stable/10:

Update kernel inclusions of capability.h to use capsicum.h instead; some
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.

Sponsored by: Google, Inc.

MFC r262678;
ufs: small formatting fixes.

Cleanup some extra space.
Use of tabs vs. spaces.
No functional change.

Reviewed by: mckusick

MFC of 260088:

Fine tune filesystem block allocations under low free-space
conditions (-r254995) based on further operational experience.

Submitted by: Dmitry Sivachenko
Fix Tested by: Dmitry Sivachenko

MFC of 269533:

Limit the number of cylinder groups that will be searched when
trying to build a cluster. The limit is tunable using the sysctl
vfs.ffs.maxclustersearch. The current limit is 10 cylinder groups
per block allocation. It was previously limited to the number of
cylinder groups in the filesystem per block allocation. When there
were no clusters of the needed size left, it repeatedly searched
the whole filesystem for a non-existent cluster on every block
allocation. The result was very slow filesystem allocation with
100% CPU utilization. The old behavior can be had by setting
vfs.ffs.maxclustersearch to a huge number (1,000,000).

This change affects only the layout policy routines so is not able
to interfere with the integrity of the filesystem.

Reported by: Dmitry Sivachenko (demon@)
Tested by: Dmitry Sivachenko (demon@)

Merge r263233 from HEAD to stable/10:

Update kernel inclusions of capability.h to use capsicum.h instead; some
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.

Sponsored by: Google, Inc.

MFC r262678;
ufs: small formatting fixes.

Cleanup some extra space.
Use of tabs vs. spaces.
No functional change.

Reviewed by: mckusick

MFC of 260088:

Fine tune filesystem block allocations under low free-space
conditions (-r254995) based on further operational experience.

Submitted by: Dmitry Sivachenko
Fix Tested by: Dmitry Sivachenko