MFC r305598:
When logging unlikely UFS_TRUNCATE() failure in ufs_direnter(),
include error code.

MFC r305597:
When extending directory inode in ufs_direnter(), adjust i_endoff.

MFC r305593:
There is no need to upgrade the last dvp lock on lookups for modifying
operations. Instead of upgrading, assert that the lock is exclusive.
Explain the cause in comments.

MFC r303090:
Ensure that the UFS directory vnode' vm_object is properly sized
before UFS_BALLOC() is called.

MFC r300082:
For async UFS mounts, shrink the directory asynchronously, at least do
not pass IO_SYNC to ffs_truncate() unneccessary.

MFC r300027:
Fix typo in the message.

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

MFC r262812

- Gracefully handle truncation failures when trying to shrink directories.
This could cause dirhash panics since the dirhash state would be
successfully truncated while the directory was not.

Submitted by: jeffr

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

MFC r262812

- Gracefully handle truncation failures when trying to shrink directories.
This could cause dirhash panics since the dirhash state would be
successfully truncated while the directory was not.

Submitted by: jeffr