- Instead of waiting forever to get a vnode in getnewvnode() wait for

   one to become available for one second and then return ENFILE.  We
   can run out of vnodes, and there must be a hard limit because without
   one we can quickly run out of KVA on x86.  Presently the system can
   deadlock if there are maxvnodes directories in the namecache.  The
   original 4.x BSD behavior was to return ENFILE if we reached the max,
   but 4.x BSD did not have the vnlru proc so it was less profitable to
   wait.

1 files changed, 3 insertions, 1 deletions

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 7cb1ac4..dfa5a68 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -815,13 +815,15 @@ getnewvnode(tag, mp, vops, vpp)
 	/*
 	 * Wait for available vnodes.
 	 */
-	while (numvnodes > desiredvnodes) {
+	if (numvnodes > desiredvnodes) {
 		if (vnlruproc_sig == 0) {
 			vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
 			wakeup(vnlruproc);
 		}
 		msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
 		    "vlruwk", hz);
+		if (numvnodes > desiredvnodes)
+			return (ENFILE);
 	}
 	numvnodes++;
 	mtx_unlock(&vnode_free_list_mtx);