K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2010-07-16T19:20:20.683585Z
K 7
svn:log
V 759
When the MNTK_EXTENDED_SHARED mount option was added, some filesystems were
changed to defer the setting of VN_LOCK_ASHARE() (which clears LK_NOSHARE
in the vnode lock's flags) until after they had determined if the vnode was
a FIFO.  This occurs after the vnode has been inserted a VFS hash or some
similar table, so it is possible for another thread to find this vnode via
vget() on an i-node number and block on the vnode lock.  If the lockmgr
interlock (vnode interlock for vnode locks) is not held when clearing the
LK_NOSHARE flag, then the lk_flags field can be clobbered.  As a result
the thread blocked on the vnode lock may never get woken up.  Fix this by
holding the vnode interlock while modifying the lock flags in this case.

MFC after:	3 days

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