K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2008-11-22T13:11:11.475386Z
K 7
svn:log
V 613
Busy ufs filesystem around block of code that does ".." lookup. Since
mnt_lock is before lock of any vnode on the mp, it uses LK_NOWAIT. Since
MNTK_UNMOUNT may be transient, pdp lock is dropped when vfs_busy()
failed, and operation is retried after some time. This way, ffs_vget()
is not called on the mp that may be in the process of being destroyed by
unmount.

Check for the VI_DOOMED flag on pdp after its lock is reacquired, to
better detect some situations where directory containing ".."
entry is removed during the lookup.

Reviewed by:	tegge, attilio (previous version)
Tested by:	pho
MFC after:	1 month

END