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diff --git a/sys/fs/unionfs/union_subr.c b/sys/fs/unionfs/union_subr.c
--- a/sys/fs/unionfs/union_subr.c
+++ b/sys/fs/unionfs/union_subr.c
@@ -525,8 +525,9 @@
}
/*
- * Get the unionfs node status.
- * You need exclusive lock this vnode.
+ * Get the unionfs node status object for the vnode corresponding to unp,
+ * for the process that owns td. Allocate a new status object if one
+ * does not already exist.
*/
void
unionfs_get_node_status(struct unionfs_node *unp, struct thread *td,
diff --git a/sys/fs/unionfs/union_vnops.c b/sys/fs/unionfs/union_vnops.c
--- a/sys/fs/unionfs/union_vnops.c
+++ b/sys/fs/unionfs/union_vnops.c
@@ -470,30 +470,73 @@
return (error);
}
+enum unionfs_lkupgrade {
+ UNIONFS_LKUPGRADE_SUCCESS, /* lock successfully upgraded */
+ UNIONFS_LKUPGRADE_ALREADY, /* lock already held exclusive */
+ UNIONFS_LKUPGRADE_DOOMED /* lock was upgraded, but vnode reclaimed */
+};
+
+static inline enum unionfs_lkupgrade
+unionfs_upgrade_lock(struct vnode *vp)
+{
+ ASSERT_VOP_LOCKED(vp, __func__);
+
+ if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
+ return (UNIONFS_LKUPGRADE_ALREADY);
+
+ if (vn_lock(vp, LK_UPGRADE) != 0) {
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ if (VN_IS_DOOMED(vp))
+ return (UNIONFS_LKUPGRADE_DOOMED);
+ }
+ return (UNIONFS_LKUPGRADE_SUCCESS);
+}
+
+static inline void
+unionfs_downgrade_lock(struct vnode *vp, enum unionfs_lkupgrade status)
+{
+ if (status != UNIONFS_LKUPGRADE_ALREADY)
+ vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
+}
+
static int
unionfs_open(struct vop_open_args *ap)
{
struct unionfs_node *unp;
struct unionfs_node_status *unsp;
+ struct vnode *vp;
struct vnode *uvp;
struct vnode *lvp;
struct vnode *targetvp;
struct ucred *cred;
struct thread *td;
int error;
+ enum unionfs_lkupgrade lkstatus;
UNIONFS_INTERNAL_DEBUG("unionfs_open: enter\n");
KASSERT_UNIONFS_VNODE(ap->a_vp);
error = 0;
- unp = VTOUNIONFS(ap->a_vp);
- uvp = unp->un_uppervp;
- lvp = unp->un_lowervp;
+ vp = ap->a_vp;
targetvp = NULLVP;
cred = ap->a_cred;
td = ap->a_td;
+ /*
+ * The executable loader path may call this function with vp locked
+ * shared. If the vnode is reclaimed while upgrading, we can't safely
+ * use unp or do anything else unionfs- specific.
+ */
+ lkstatus = unionfs_upgrade_lock(vp);
+ if (lkstatus == UNIONFS_LKUPGRADE_DOOMED) {
+ error = ENOENT;
+ goto unionfs_open_cleanup;
+ }
+
+ unp = VTOUNIONFS(vp);
+ uvp = unp->un_uppervp;
+ lvp = unp->un_lowervp;
unionfs_get_node_status(unp, td, &unsp);
if (unsp->uns_lower_opencnt > 0 || unsp->uns_upper_opencnt > 0) {
@@ -540,13 +583,16 @@
unsp->uns_lower_opencnt++;
unsp->uns_lower_openmode = ap->a_mode;
}
- ap->a_vp->v_object = targetvp->v_object;
+ vp->v_object = targetvp->v_object;
}
unionfs_open_abort:
if (error != 0)
unionfs_tryrem_node_status(unp, unsp);
+unionfs_open_cleanup:
+ unionfs_downgrade_lock(vp, lkstatus);
+
UNIONFS_INTERNAL_DEBUG("unionfs_open: leave (%d)\n", error);
return (error);
@@ -562,23 +608,26 @@
struct vnode *vp;
struct vnode *ovp;
int error;
- int locked;
+ enum unionfs_lkupgrade lkstatus;;
UNIONFS_INTERNAL_DEBUG("unionfs_close: enter\n");
KASSERT_UNIONFS_VNODE(ap->a_vp);
- locked = 0;
vp = ap->a_vp;
- unp = VTOUNIONFS(vp);
cred = ap->a_cred;
td = ap->a_td;
+ error = 0;
- if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
- if (vn_lock(vp, LK_UPGRADE) != 0)
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- locked = 1;
- }
+ /*
+ * If the vnode is reclaimed while upgrading, we can't safely use unp
+ * or do anything else unionfs- specific.
+ */
+ lkstatus = unionfs_upgrade_lock(vp);
+ if (lkstatus == UNIONFS_LKUPGRADE_DOOMED)
+ goto unionfs_close_cleanup;
+
+ unp = VTOUNIONFS(vp);
unionfs_get_node_status(unp, td, &unsp);
if (unsp->uns_lower_opencnt <= 0 && unsp->uns_upper_opencnt <= 0) {
@@ -618,8 +667,8 @@
unionfs_close_abort:
unionfs_tryrem_node_status(unp, unsp);
- if (locked != 0)
- vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
+unionfs_close_cleanup:
+ unionfs_downgrade_lock(vp, lkstatus);
UNIONFS_INTERNAL_DEBUG("unionfs_close: leave (%d)\n", error);
@@ -1444,6 +1493,11 @@
VNPASS(vrefcnt(ap->a_vp) > 0, ap->a_vp);
error = unionfs_relookup_for_delete(ap->a_dvp, cnp, td);
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
+ /*
+ * VOP_RMDIR is dispatched against udvp, so if uvp became
+ * doomed while the lock was dropped above the target
+ * filesystem may not be able to cope.
+ */
if (error == 0 && VN_IS_DOOMED(uvp))
error = ENOENT;
if (error == 0)
@@ -1514,9 +1568,9 @@
uint64_t *cookies_bk;
int error;
int eofflag;
- int locked;
int ncookies_bk;
int uio_offset_bk;
+ enum unionfs_lkupgrade lkstatus;
UNIONFS_INTERNAL_DEBUG("unionfs_readdir: enter\n");
@@ -1524,7 +1578,6 @@
error = 0;
eofflag = 0;
- locked = 0;
uio_offset_bk = 0;
uio = ap->a_uio;
uvp = NULLVP;
@@ -1537,18 +1590,18 @@
if (vp->v_type != VDIR)
return (ENOTDIR);
- /* check the open count. unionfs needs to open before readdir. */
- if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
- if (vn_lock(vp, LK_UPGRADE) != 0)
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- locked = 1;
- }
- unp = VTOUNIONFS(vp);
- if (unp == NULL)
+ /*
+ * If the vnode is reclaimed while upgrading, we can't safely use unp
+ * or do anything else unionfs- specific.
+ */
+ lkstatus = unionfs_upgrade_lock(vp);
+ if (lkstatus == UNIONFS_LKUPGRADE_DOOMED)
error = EBADF;
- else {
+ if (error == 0) {
+ unp = VTOUNIONFS(vp);
uvp = unp->un_uppervp;
lvp = unp->un_lowervp;
+ /* check the open count. unionfs needs open before readdir. */
unionfs_get_node_status(unp, td, &unsp);
if ((uvp != NULLVP && unsp->uns_upper_opencnt <= 0) ||
(lvp != NULLVP && unsp->uns_lower_opencnt <= 0)) {
@@ -1556,8 +1609,7 @@
error = EBADF;
}
}
- if (locked)
- vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
+ unionfs_downgrade_lock(vp, lkstatus);
if (error != 0)
goto unionfs_readdir_exit;
@@ -1906,7 +1958,8 @@
if ((revlock = unionfs_get_llt_revlock(vp, flags)) == 0)
panic("unknown lock type: 0x%x", flags & LK_TYPE_MASK);
- if ((vp->v_iflag & VI_OWEINACT) != 0)
+ if ((flags & LK_TYPE_MASK) != LK_DOWNGRADE &&
+ (vp->v_iflag & VI_OWEINACT) != 0)
flags |= LK_NOWAIT;
/*
@@ -2251,10 +2304,12 @@
if (error == 0) {
if (vn_lock(vp, LK_UPGRADE) != 0)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- if (tvp == unp->un_uppervp)
- unp->un_flag |= UNIONFS_OPENEXTU;
- else
- unp->un_flag |= UNIONFS_OPENEXTL;
+ if (!VN_IS_DOOMED(vp)) {
+ if (tvp == unp->un_uppervp)
+ unp->un_flag |= UNIONFS_OPENEXTU;
+ else
+ unp->un_flag |= UNIONFS_OPENEXTL;
+ }
vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
}
@@ -2288,10 +2343,12 @@
if (error == 0) {
if (vn_lock(vp, LK_UPGRADE) != 0)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- if (tvp == unp->un_uppervp)
- unp->un_flag &= ~UNIONFS_OPENEXTU;
- else
- unp->un_flag &= ~UNIONFS_OPENEXTL;
+ if (!VN_IS_DOOMED(vp)) {
+ if (tvp == unp->un_uppervp)
+ unp->un_flag &= ~UNIONFS_OPENEXTU;
+ else
+ unp->un_flag &= ~UNIONFS_OPENEXTL;
+ }
vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
}

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