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diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -2429,6 +2429,10 @@
return (setfown(td, active_cred, vp, uid, gid));
}
+/*
+ * Remove pages in the range ["start", "end") from the vnode's VM object. If
+ * "end" is 0, then the range extends to the end of the object.
+ */
void
vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
{
@@ -2441,6 +2445,24 @@
VM_OBJECT_WUNLOCK(object);
}
+/*
+ * Like vn_pages_remove(), but skips invalid pages, which by definition are not
+ * mapped into any process' address space. Filesystems may use this in
+ * preference to vn_pages_remove() to avoid blocking on pages busied in
+ * preparation for a VOP_GETPAGES.
+ */
+void
+vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
+{
+ vm_object_t object;
+
+ if ((object = vp->v_object) == NULL)
+ return;
+ VM_OBJECT_WLOCK(object);
+ vm_object_page_remove(object, start, end, OBJPR_VALIDONLY);
+ VM_OBJECT_WUNLOCK(object);
+}
+
int
vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off,
struct ucred *cred)
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -770,6 +770,8 @@
int vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
struct thread *td, struct file *fp);
void vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end);
+void vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start,
+ vm_pindex_t end);
int vn_pollrecord(struct vnode *vp, struct thread *p, int events);
int vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base,
int len, off_t offset, enum uio_seg segflg, int ioflg,
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -232,6 +232,7 @@
*/
#define OBJPR_CLEANONLY 0x1 /* Don't remove dirty pages. */
#define OBJPR_NOTMAPPED 0x2 /* Don't unmap pages. */
+#define OBJPR_VALIDONLY 0x4 /* Ignore invalid pages. */
TAILQ_HEAD(object_q, vm_object);
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -2099,6 +2099,21 @@
for (; p != NULL && (p->pindex < end || end == 0); p = next) {
next = TAILQ_NEXT(p, listq);
+ /*
+ * Skip invalid pages if asked to do so. Try to avoid acquiring
+ * the busy lock, as some consumers rely on this to avoid
+ * deadlocks.
+ *
+ * A thread may concurrently transition the page from invalid to
+ * valid using only the busy lock, so the result of this check
+ * is immediately stale. It is up to consumers to handle this,
+ * for instance by ensuring that all invalid->valid transitions
+ * happen with a mutex held, as may be possible for a
+ * filesystem.
+ */
+ if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p))
+ continue;
+
/*
* If the page is wired for any reason besides the existence
* of managed, wired mappings, then it cannot be freed. For
@@ -2112,6 +2127,10 @@
VM_OBJECT_WLOCK(object);
goto again;
}
+ if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) {
+ vm_page_xunbusy(p);
+ continue;
+ }
if (vm_page_wired(p)) {
wired:
if ((options & OBJPR_NOTMAPPED) == 0 &&

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