MFC r304232:
In UFS_BALLOC(), invalidate pages of indirect buffers on failed block
allocation unwinding.

MFC r304231:
On unwind after failed block allocation in ffs_balloc_ufs{1,2}, assert
that recorded allocated blocks numbers match the physical block numbers
of dandling buffers which are released.
When finally freeing the blocks during unwind, assert that dandling
buffers where not re-allocated.

MFC r304229:
When looking up dandling buffers for unwing after failing block
allocation in UFS_BALLOC(), there is no need to map them.

MFC r304228:
When block allocation fails in UFS_BALLOC(), and the volume does not
have SU enabled, there is no point in calling softdep_request_cleanup().

MFC r304227:
In ffs_balloc_ufs{1,2} routines, assert that unwind records do not
overflow local arrays.

MFC r290047:
Do not perform read-ahead for BA_CLRBUF request when we are low on
memory or when dirty buffer queue is too large.

MFC r262678;
ufs: small formatting fixes.

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

Reviewed by: mckusick

MFC r262678;
ufs: small formatting fixes.

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

Reviewed by: mckusick