In nfs_upgrade_vnlock(), assert that the vnode is locked. It is for all
pathes, as far as I see and testing seems to confirm it. Comparision of old_lock with LK_SHARED make sense only if vnode is locked by current thread. When downgrading, pass LK_RETRY to the vn_lock(), since otherwise vn_lock() unlocks the doomed vnode, causing extra unlock. Reported and tested by: pho Approved by: re (rwatson) MFC after: 3 weeks
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=196205
@ -409,28 +409,25 @@ int
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nfs_upgrade_vnlock(struct vnode *vp)
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{
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int old_lock;
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if ((old_lock = VOP_ISLOCKED(vp)) != LK_EXCLUSIVE) {
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if (old_lock == LK_SHARED) {
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/* Upgrade to exclusive lock, this might block */
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vn_lock(vp, LK_UPGRADE | LK_RETRY);
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} else {
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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}
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ASSERT_VOP_LOCKED(vp, "nfs_upgrade_vnlock");
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old_lock = VOP_ISLOCKED(vp);
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if (old_lock != LK_EXCLUSIVE) {
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KASSERT(old_lock == LK_SHARED,
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("nfs_upgrade_vnlock: wrong old_lock %d", old_lock));
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/* Upgrade to exclusive lock, this might block */
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vn_lock(vp, LK_UPGRADE | LK_RETRY);
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}
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return old_lock;
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return (old_lock);
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}
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void
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nfs_downgrade_vnlock(struct vnode *vp, int old_lock)
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{
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if (old_lock != LK_EXCLUSIVE) {
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if (old_lock == LK_SHARED) {
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/* Downgrade from exclusive lock, this might block */
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vn_lock(vp, LK_DOWNGRADE);
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} else {
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VOP_UNLOCK(vp, 0);
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}
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KASSERT(old_lock == LK_SHARED, ("wrong old_lock %d", old_lock));
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/* Downgrade from exclusive lock. */
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vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
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}
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}
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