Author: trociny
Date: Sat Feb 25 10:15:41 2012
New Revision: 232152
URL: http://svn.freebsd.org/changeset/base/232152
Log:
When detaching an unix domain socket, uipc_detach() checks
unp->unp_vnode pointer to detect if there is a vnode associated with
(binded to) this socket and does necessary cleanup if there is.
The issue is that after forced unmount this check may be too late as
the unp_vnode is reclaimed and the reference is stale.
To fix this provide a helper function that is called on a socket vnode
reclamation to do necessary cleanup.
Pointed by: kib
Reviewed by: kib
MFC after: 2 weeks
Modified:
head/sys/kern/uipc_usrreq.c
head/sys/kern/vfs_subr.c
head/sys/sys/vnode.h
Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c Sat Feb 25 10:10:43 2012 (r232151)
+++ head/sys/kern/uipc_usrreq.c Sat Feb 25 10:15:41 2012 (r232152)
@@ -2300,6 +2300,45 @@ unp_scan(struct mbuf *m0, void (*op)(str
}
}
+/*
+ * A helper function called by VFS before socket-type vnode reclamation.
+ * For an active vnode it clears unp_vnode pointer and decrements unp_vnode
+ * use count.
+ */
+void
+vfs_unp_reclaim(struct vnode *vp)
+{
+ struct socket *so;
+ struct unpcb *unp;
+ int active;
+
+ ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
+ KASSERT(vp->v_type == VSOCK,
+ ("vfs_unp_reclaim: vp->v_type != VSOCK"));
+
+ active = 0;
+ UNP_LINK_WLOCK();
+ so = vp->v_socket;
+ if (so == NULL)
+ goto done;
+ unp = sotounpcb(so);
+ if (unp == NULL)
+ goto done;
+ UNP_PCB_LOCK(unp);
+ if (unp->unp_vnode != NULL) {
+ KASSERT(unp->unp_vnode == vp,
+ ("vfs_unp_reclaim: vp != unp->unp_vnode"));
+ vp->v_socket = NULL;
+ unp->unp_vnode = NULL;
+ active = 1;
+ }
+ UNP_PCB_UNLOCK(unp);
+done:
+ UNP_LINK_WUNLOCK();
+ if (active)
+ vunref(vp);
+}
+
#ifdef DDB
static void
db_print_indent(int indent)
Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c Sat Feb 25 10:10:43 2012 (r232151)
+++ head/sys/kern/vfs_subr.c Sat Feb 25 10:15:41 2012 (r232152)
@@ -2657,6 +2657,8 @@ vgonel(struct vnode *vp)
vinactive(vp, td);
VI_UNLOCK(vp);
}
+ if (vp->v_type == VSOCK)
+ vfs_unp_reclaim(vp);
/*
* Reclaim the vnode.
*/
Modified: head/sys/sys/vnode.h
==============================================================================
--- head/sys/sys/vnode.h Sat Feb 25 10:10:43 2012 (r232151)
+++ head/sys/sys/vnode.h Sat Feb 25 10:15:41 2012 (r232152)
@@ -793,6 +793,8 @@ int vfs_read_dirent(struct vop_readdir_a
int vfs_unixify_accmode(accmode_t *accmode);
+void vfs_unp_reclaim(struct vnode *vp);
+
int setfmode(struct thread *td, struct ucred *cred, struct vnode *vp, int
mode);
int setfown(struct thread *td, struct ucred *cred, struct vnode *vp, uid_t uid,
gid_t gid);
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