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- Don't acquire the vnode interlock in _vn_lock() unless no lock type

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is requested.  Handle this case specially before the while loop.
 - Use the held vnode lock to check for VI_DOOMED.  The vnode lock and
   interlock must both be held to set VI_DOOMED so either one held, even
   shared, is sufficient to check it.

No objection by:	kib
This commit is contained in:
Jeff Roberson 2008-03-24 04:17:35 +00:00
parent 97735db712
commit 804e60d4cf
1 changed files with 13 additions and 19 deletions
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32
sys/kern/vfs_vnops.c
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@ -862,27 +862,21 @@ _vn_lock(struct vnode *vp, int flags, char *file, int line)
{
int error;
do {
/*
* With no lock type requested we're just polling for validity.
*/
if ((flags & LK_TYPE_MASK) == 0) {
error = 0;
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
if ((flags & LK_NOWAIT || (flags & LK_TYPE_MASK) == 0) &&
vp->v_iflag & VI_DOOMED) {
VI_UNLOCK(vp);
return (ENOENT);
}
/*
* Just polling to check validity.
*/
if ((flags & LK_TYPE_MASK) == 0) {
VI_UNLOCK(vp);
return (0);
}
/*
* lockmgr drops interlock before it will return for
* any reason. So force the code above to relock it.
*/
error = VOP_LOCK1(vp, flags | LK_INTERLOCK, file, line);
flags &= ~LK_INTERLOCK;
if (vp->v_iflag & VI_DOOMED)
error = ENOENT;
VI_UNLOCK(vp);
return (error);
}
do {
error = VOP_LOCK1(vp, flags, file, line);
flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
KASSERT((flags & LK_RETRY) == 0 || error == 0,
("LK_RETRY set with incompatible flags %d\n", flags));
/*