Bug#630783: kfreebsd-9: lock order reversal (bufwait vs dirhash) in ufs_direnter

[Jonathan Nieder <jrnieder@gmail.com>]

tags 630783 + upstream
clone 630783 -1
retitle -1 kfreebsd-10: lock order reversal (bufwait vs dirhash) in ufs_direnter
reassign -1 kfreebsd-10 kfreebsd-10/10.0~svn226872-1
# typical order: fix in CURRENT first, then mfc
block 630783 by -1
quit

Jonathan Nieder wrote:

> | lock order reversal:
> |  1st 0xffffff803d300018 bufwait (bufwait) @ kern/vfs_bio.c:2658
> |  2nd 0xfffffe000257e800 dirhash (dirhash) @ ufs/ufs/ufs_dirhash.c:284

Likewise in kfreebsd-10.  I don't think this code has been touched
recently.