Author: kib
Date: Mon Sep 7 12:10:41 2009
New Revision: 196921
URL: http://svn.freebsd.org/changeset/base/196921
Log:
If a race is detected, pfs_vncache_alloc() may reclaim a vnode that had
never been inserted into the pfs_vncache list. Since pfs_vncache_free()
does not anticipate this case, it decrements pfs_vncache_entries
unconditionally; if the vnode was not in the list, pfs_vncache_entries
will no longer reflect the actual number of list entries. This may cause
size of the cache to exceed the configured maximum. It may also trigger
a panic during module unload or system shutdown.
Do not decrement pfs_vncache_entries for the vnode that was not in the
list.
Submitted by: tegge
Reviewed by: des
MFC after: 1 week
Modified:
head/sys/fs/pseudofs/pseudofs_vncache.c
Modified: head/sys/fs/pseudofs/pseudofs_vncache.c
==============================================================================
--- head/sys/fs/pseudofs/pseudofs_vncache.c Mon Sep 7 11:55:34 2009
(r196920)
+++ head/sys/fs/pseudofs/pseudofs_vncache.c Mon Sep 7 12:10:41 2009
(r196921)
@@ -246,11 +246,13 @@ pfs_vncache_free(struct vnode *vp)
KASSERT(pvd != NULL, ("pfs_vncache_free(): no vnode data\n"));
if (pvd->pvd_next)
pvd->pvd_next->pvd_prev = pvd->pvd_prev;
- if (pvd->pvd_prev)
+ if (pvd->pvd_prev) {
pvd->pvd_prev->pvd_next = pvd->pvd_next;
- else if (pfs_vncache == pvd)
+ --pfs_vncache_entries;
+ } else if (pfs_vncache == pvd) {
pfs_vncache = pvd->pvd_next;
- --pfs_vncache_entries;
+ --pfs_vncache_entries;
+ }
mtx_unlock(&pfs_vncache_mutex);
free(pvd, M_PFSVNCACHE);
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