svn commit: r353890 - in head/sys: sys vm
Konstantin Belousov
kib at FreeBSD.org
Tue Oct 22 16:09:27 UTC 2019
Author: kib
Date: Tue Oct 22 16:09:25 2019
New Revision: 353890
URL: https://svnweb.freebsd.org/changeset/base/353890
Log:
Add VV_VMSIZEVNLOCK flag.
The flag specifies that vm_fault() handler should check the vnode'
vm_object size under the vnode lock. It is converted into the object'
OBJ_SIZEVNLOCK flag in vnode_pager_alloc().
Tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D21883
Modified:
head/sys/sys/vnode.h
head/sys/vm/vm_fault.c
head/sys/vm/vm_object.h
head/sys/vm/vnode_pager.c
Modified: head/sys/sys/vnode.h
==============================================================================
--- head/sys/sys/vnode.h Tue Oct 22 16:06:33 2019 (r353889)
+++ head/sys/sys/vnode.h Tue Oct 22 16:09:25 2019 (r353890)
@@ -247,6 +247,7 @@ struct xvnode {
#define VV_NOSYNC 0x0004 /* unlinked, stop syncing */
#define VV_ETERNALDEV 0x0008 /* device that is never destroyed */
#define VV_CACHEDLABEL 0x0010 /* Vnode has valid cached MAC label */
+#define VV_VMSIZEVNLOCK 0x0020 /* object size check requires vnode lock */
#define VV_COPYONWRITE 0x0040 /* vnode is doing copy-on-write */
#define VV_SYSTEM 0x0080 /* vnode being used by kernel */
#define VV_PROCDEP 0x0100 /* vnode is process dependent */
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Tue Oct 22 16:06:33 2019 (r353889)
+++ head/sys/vm/vm_fault.c Tue Oct 22 16:09:25 2019 (r353890)
@@ -887,6 +887,13 @@ RetryFault_oom:
*/
if (fs.object->type != OBJT_DEFAULT ||
fs.object == fs.first_object) {
+ if ((fs.object->flags & OBJ_SIZEVNLOCK) != 0) {
+ rv = vm_fault_lock_vnode(&fs);
+ MPASS(rv == KERN_SUCCESS ||
+ rv == KERN_RESOURCE_SHORTAGE);
+ if (rv == KERN_RESOURCE_SHORTAGE)
+ goto RetryFault;
+ }
if (fs.pindex >= fs.object->size) {
unlock_and_deallocate(&fs);
return (KERN_OUT_OF_BOUNDS);
Modified: head/sys/vm/vm_object.h
==============================================================================
--- head/sys/vm/vm_object.h Tue Oct 22 16:06:33 2019 (r353889)
+++ head/sys/vm/vm_object.h Tue Oct 22 16:09:25 2019 (r353890)
@@ -186,6 +186,7 @@ struct vm_object {
#define OBJ_DEAD 0x0008 /* dead objects (during rundown) */
#define OBJ_NOSPLIT 0x0010 /* dont split this object */
#define OBJ_UMTXDEAD 0x0020 /* umtx pshared was terminated */
+#define OBJ_SIZEVNLOCK 0x0040 /* lock vnode to check obj size */
#define OBJ_PG_DTOR 0x0080 /* dont reset object, leave that for dtor */
#define OBJ_MIGHTBEDIRTY 0x0100 /* object might be dirty, only for vnode */
#define OBJ_TMPFS_NODE 0x0200 /* object belongs to tmpfs VREG node */
Modified: head/sys/vm/vnode_pager.c
==============================================================================
--- head/sys/vm/vnode_pager.c Tue Oct 22 16:06:33 2019 (r353889)
+++ head/sys/vm/vnode_pager.c Tue Oct 22 16:09:25 2019 (r353890)
@@ -269,8 +269,12 @@ retry:
object->un_pager.vnp.vnp_size = size;
object->un_pager.vnp.writemappings = 0;
object->domain.dr_policy = vnode_domainset;
-
object->handle = handle;
+ if ((vp->v_vflag & VV_VMSIZEVNLOCK) != 0) {
+ VM_OBJECT_WLOCK(object);
+ vm_object_set_flag(object, OBJ_SIZEVNLOCK);
+ VM_OBJECT_WUNLOCK(object);
+ }
VI_LOCK(vp);
if (vp->v_object != NULL) {
/*
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