Provide vnode in memory map info for files on tmpfs

When providing memory map information to userland, populate the vnode pointer
for tmpfs files.  Set the memory mapping to appear as a vnode type, to match
FreeBSD 9 behavior.

This fixes the use of tmpfs files with the dtrace pid provider,
procstat -v, procfs, linprocfs, pmc (pmcstat), and ptrace (PT_VM_ENTRY).

Submitted by:   Eric Badger <eric@badgerio.us> (initial revision)
Obtained from:  Dell Inc.
PR:             198431
MFC after:      2 weeks
Reviewed by:    jhb
Approved by:    kib (mentor)

7 files changed, 49 insertions, 18 deletions

diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index 00d0286..25a8325 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -1025,20 +1025,16 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
 		ino = 0;
 		if (lobj) {
 			off = IDX_TO_OFF(lobj->size);
-			if (lobj->type == OBJT_VNODE) {
-				vp = lobj->handle;
-				if (vp)
-					vref(vp);
-			}
-			else
-				vp = NULL;
+			vp = vm_object_vnode(lobj);
+			if (vp != NULL)
+				vref(vp);
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
 			flags = obj->flags;
 			ref_count = obj->ref_count;
 			shadow_count = obj->shadow_count;
 			VM_OBJECT_RUNLOCK(obj);
-			if (vp) {
+			if (vp != NULL) {
 				vn_fullpath(td, vp, &name, &freename);
 				vn_lock(vp, LK_SHARED | LK_RETRY);
 				VOP_GETATTR(vp, &vat, td->td_ucred);
diff --git a/sys/dev/hwpmc/hwpmc_mod.c b/sys/dev/hwpmc/hwpmc_mod.c
index d1b56f1..131eb35 100644
--- a/sys/dev/hwpmc/hwpmc_mod.c
+++ b/sys/dev/hwpmc/hwpmc_mod.c
@@ -1655,7 +1655,8 @@ pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
 			continue;
 		}
 
-		if (lobj->type != OBJT_VNODE || lobj->handle == NULL) {
+		vp = vm_object_vnode(lobj);
+		if (vp == NULL) {
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
 			VM_OBJECT_RUNLOCK(obj);
@@ -1667,7 +1668,7 @@ pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
 		 * vnode, so we don't emit redundant MAP-IN
 		 * directives.
 		 */
-		if (entry->start == last_end && lobj->handle == last_vp) {
+		if (entry->start == last_end && vp == last_vp) {
 			last_end = entry->end;
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
@@ -1690,7 +1691,6 @@ pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
 		last_timestamp = map->timestamp;
 		vm_map_unlock_read(map);
 
-		vp = lobj->handle;
 		vref(vp);
 		if (lobj != obj)
 			VM_OBJECT_RUNLOCK(lobj);
diff --git a/sys/fs/procfs/procfs_map.c b/sys/fs/procfs/procfs_map.c
index eae70229..b00aac3 100644
--- a/sys/fs/procfs/procfs_map.c
+++ b/sys/fs/procfs/procfs_map.c
@@ -159,11 +159,11 @@ procfs_doprocmap(PFS_FILL_ARGS)
 		freepath = NULL;
 		fullpath = "-";
 		if (lobj) {
+			vp = NULL;
 			switch (lobj->type) {
 			default:
 			case OBJT_DEFAULT:
 				type = "default";
-				vp = NULL;
 				break;
 			case OBJT_VNODE:
 				type = "vnode";
@@ -171,13 +171,19 @@ procfs_doprocmap(PFS_FILL_ARGS)
 				vref(vp);
 				break;
 			case OBJT_SWAP:
-				type = "swap";
-				vp = NULL;
+				if ((lobj->flags & OBJ_TMPFS_NODE) != 0) {
+					type = "vnode";
+					if ((lobj->flags & OBJ_TMPFS) != 0) {
+						vp = lobj->un_pager.swp.swp_tmpfs;
+						vref(vp);
+					}
+				} else {
+					type = "swap";
+				}
 				break;
 			case OBJT_SG:
 			case OBJT_DEVICE:
 				type = "device";
-				vp = NULL;
 				break;
 			}
 			if (lobj != obj)
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 6618c08..fc33feb 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -2113,7 +2113,15 @@ sysctl_kern_proc_ovmmap(SYSCTL_HANDLER_ARGS)
 				vref(vp);
 				break;
 			case OBJT_SWAP:
-				kve->kve_type = KVME_TYPE_SWAP;
+				if ((lobj->flags & OBJ_TMPFS_NODE) != 0) {
+					kve->kve_type = KVME_TYPE_VNODE;
+					if ((lobj->flags & OBJ_TMPFS) != 0) {
+						vp = lobj->un_pager.swp.swp_tmpfs;
+						vref(vp);
+					}
+				} else {
+					kve->kve_type = KVME_TYPE_SWAP;
+				}
 				break;
 			case OBJT_DEVICE:
 				kve->kve_type = KVME_TYPE_DEVICE;
@@ -2339,7 +2347,15 @@ kern_proc_vmmap_out(struct proc *p, struct sbuf *sb)
 				vref(vp);
 				break;
 			case OBJT_SWAP:
-				kve->kve_type = KVME_TYPE_SWAP;
+				if ((lobj->flags & OBJ_TMPFS_NODE) != 0) {
+					kve->kve_type = KVME_TYPE_VNODE;
+					if ((lobj->flags & OBJ_TMPFS) != 0) {
+						vp = lobj->un_pager.swp.swp_tmpfs;
+						vref(vp);
+					}
+				} else {
+					kve->kve_type = KVME_TYPE_SWAP;
+				}
 				break;
 			case OBJT_DEVICE:
 				kve->kve_type = KVME_TYPE_DEVICE;
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 09a43f4..d82fda0 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -402,7 +402,7 @@ ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 			lobj = tobj;
 			pve->pve_offset += tobj->backing_object_offset;
 		}
-		vp = (lobj->type == OBJT_VNODE) ? lobj->handle : NULL;
+		vp = vm_object_vnode(lobj);
 		if (vp != NULL)
 			vref(vp);
 		if (lobj != obj)
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 30623b2..e240b67 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -2287,6 +2287,18 @@ next_page:
 	}
 }
 
+struct vnode *
+vm_object_vnode(vm_object_t object)
+{
+
+	VM_OBJECT_ASSERT_LOCKED(object);
+	if (object->type == OBJT_VNODE)
+		return (object->handle);
+	if (object->type == OBJT_SWAP && (object->flags & OBJ_TMPFS) != 0)
+		return (object->un_pager.swp.swp_tmpfs);
+	return (NULL);
+}
+
 static int
 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS)
 {
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index 731c9e3..1f59156 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -322,6 +322,7 @@ boolean_t vm_object_sync(vm_object_t, vm_ooffset_t, vm_size_t, boolean_t,
     boolean_t);
 void vm_object_unwire(vm_object_t object, vm_ooffset_t offset,
     vm_size_t length, uint8_t queue);
+struct vnode *vm_object_vnode(vm_object_t object);
 #endif				/* _KERNEL */
 
 #endif				/* _VM_OBJECT_ */