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- Don't allow calls to vn_lock() with no lock type requested. Callers

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which simply want a reference should use vref().  Callers which want
   to check validity need to hold a lock while performing any action
   based on that validity.  vn_lock() would always release the interlock
   before returning making any action synchronous with the validity check
   impossible.
This commit is contained in:
Jeff Roberson 2008-03-29 23:36:26 +00:00
parent 069c6953a0
commit 5634d48667
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=177727
1 changed files with 4 additions and 14 deletions
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18
sys/kern/vfs_vnops.c
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@ -854,26 +854,16 @@ vn_poll(fp, events, active_cred, td)
}
/*
* Check that the vnode is still valid, and if so
* acquire requested lock.
* Acquire the requested lock and then check for validity. LK_RETRY
* permits vn_lock to return doomed vnodes.
*/
int
_vn_lock(struct vnode *vp, int flags, char *file, int line)
{
int error;
/*
* 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 (vp->v_iflag & VI_DOOMED)
error = ENOENT;
VI_UNLOCK(vp);
return (error);
}
VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
("vn_lock called with no locktype."));
do {
error = VOP_LOCK1(vp, flags, file, line);
flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */