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In lf_advlockasync(), recheck for doomed vnode after the state->ls_lock

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is acquired. In the lf_purgelocks(), assert that vnode is doomed and set
*statep to NULL before clearing ls_pending list. Otherwise, we allow for
the thread executing lf_advlockasync() to put new pending entry after
state->ls_lock is dropped in lf_purgelocks().

Reviewed by:	dfr
Tested by:	pho
MFC after:	1 month
This commit is contained in:
Konstantin Belousov 2009-05-24 12:33:16 +00:00
parent 47e6a3971f
commit b33d617717
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=192683
1 changed files with 17 additions and 2 deletions
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19
sys/kern/kern_lockf.c
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@ -633,7 +633,20 @@ lf_advlockasync(struct vop_advlockasync_args *ap, struct lockf **statep,
}
sx_xlock(&state->ls_lock);
switch(ap->a_op) {
/*
* Recheck the doomed vnode after state->ls_lock is
* locked. lf_purgelocks() requires that no new threads add
* pending locks when vnode is marked by VI_DOOMED flag.
*/
VI_LOCK(vp);
if (vp->v_iflag & VI_DOOMED) {
VI_UNLOCK(vp);
lf_free_lock(lock);
return (ENOENT);
}
VI_UNLOCK(vp);
switch (ap->a_op) {
case F_SETLK:
error = lf_setlock(state, lock, vp, ap->a_cookiep);
break;
@ -755,8 +768,11 @@ lf_purgelocks(struct vnode *vp, struct lockf **statep)
* the remaining locks.
*/
VI_LOCK(vp);
KASSERT(vp->v_iflag & VI_DOOMED,
("lf_purgelocks: vp %p has not vgone yet", vp));
state = *statep;
if (state) {
*statep = NULL;
state->ls_threads++;
VI_UNLOCK(vp);
@ -789,7 +805,6 @@ lf_purgelocks(struct vnode *vp, struct lockf **statep)
VI_LOCK(vp);
while (state->ls_threads > 1)
msleep(state, VI_MTX(vp), 0, "purgelocks", 0);
*statep = 0;
VI_UNLOCK(vp);
/*