/* osi_vm.c implements:
*
- * osi_VM_FlushVCache(avc, slept)
+ * osi_VM_FlushVCache(avc)
* osi_ubc_flush_dirty_and_wait(vp, flags)
* osi_VM_StoreAllSegments(avc)
* osi_VM_TryToSmush(avc, acred, sync)
#include <afsconfig.h>
#include "afs/param.h"
+#include <sys/param.h>
+#include <sys/vnode.h>
-RCSID
- ("$Header$");
#include "afs/sysincludes.h" /* Standard vendor system headers */
#include "afsincludes.h" /* Afs-based standard headers */
#include "afs/afs_stats.h" /* statistics */
#include <vm/vm_object.h>
#include <vm/vm_map.h>
-#include <limits.h>
-#include <float.h>
+#include <sys/limits.h>
+#if __FreeBSD_version >= 1000030
+#include <sys/rwlock.h>
+#endif
+
+/*
+ * FreeBSD implementation notes:
+ * Most of these operations require us to frob vm_objects. Most
+ * functions require that the object be locked (with VM_OBJECT_*LOCK)
+ * on entry and leave it locked on exit. The locking protocol
+ * requires that we access vp->v_object with the heavy vnode lock
+ * held and the vnode interlock unlocked.
+ *
+ * The locking protocol for vnodes is defined in
+ * kern/vnode_if.src and sys/vnode.h; unfortunately, it is not *quite*
+ * constant from version to version so to be properly correct we must
+ * check the VCS history of those files.
+ */
+
+#if defined(AFS_FBSD80_ENV)
+#define lock_vnode(v, f) vn_lock((v), (f))
+#define ilock_vnode(v) vn_lock((v), LK_INTERLOCK|LK_EXCLUSIVE|LK_RETRY)
+#define unlock_vnode(v) VOP_UNLOCK((v), 0)
+#define islocked_vnode(v) VOP_ISLOCKED((v))
+#else
+#define lock_vnode(v, f) vn_lock((v), (f), curthread)
+#define ilock_vnode(v) vn_lock((v), LK_INTERLOCK|LK_EXCLUSIVE|LK_RETRY, curthread)
+#define unlock_vnode(v) VOP_UNLOCK((v), 0, curthread)
+#define islocked_vnode(v) VOP_ISLOCKED((v), curthread)
+#endif
+
+#if __FreeBSD_version >= 1000030
+#define AFS_VM_OBJECT_WLOCK(o) VM_OBJECT_WLOCK(o)
+#define AFS_VM_OBJECT_WUNLOCK(o) VM_OBJECT_WUNLOCK(o)
+#else
+#define AFS_VM_OBJECT_WLOCK(o) VM_OBJECT_LOCK(o)
+#define AFS_VM_OBJECT_WUNLOCK(o) VM_OBJECT_UNLOCK(o)
+#endif
/* Try to discard pages, in order to recycle a vcache entry.
*
* We also do some non-VM-related chores, such as releasing the cred pointer
* (for AIX and Solaris) and releasing the gnode (for AIX).
*
- * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
- * *slept should be set to warn the caller.
- *
- * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
- * is not dropped and re-acquired for any platform. It may be that *slept is
- * therefore obsolescent.
+ * Locking: afs_xvcache lock is held. It must not be dropped.
*
- * OSF/1 Locking: VN_LOCK has been called.
*/
int
-osi_VM_FlushVCache(struct vcache *avc, int *slept)
+osi_VM_FlushVCache(struct vcache *avc)
{
- struct vm_object *obj;
struct vnode *vp;
- if (VREFCOUNT(avc) > 1)
- return EBUSY;
+ int code;
- if (avc->opens)
- return EBUSY;
+ vp = AFSTOV(avc);
- /* if a lock is held, give up */
- if (CheckLock(&avc->lock) || afs_CheckBozonLock(&avc->pvnLock))
+ if (!VI_TRYLOCK(vp))
return EBUSY;
+ code = osi_fbsd_checkinuse(avc);
+ if (code) {
+ VI_UNLOCK(vp);
+ return code;
+ }
+
+ /* must hold the vnode before calling cache_purge()
+ * This code largely copied from vfs_subr.c:vlrureclaim() */
+ vholdl(vp);
+ VI_UNLOCK(vp);
AFS_GUNLOCK();
- vp = AFSTOV(avc);
- simple_lock(&vp->v_interlock);
- if (VOP_GETVOBJECT(vp, &obj) == 0) {
- vm_object_page_remove(obj, 0, 0, FALSE);
-#if 0
- if (obj->ref_count == 0) {
- vgonel(vp, curproc);
- simple_lock(&vp->v_interlock);
- vp->v_tag = VT_AFS;
- SetAfsVnode(vp);
- }
-#endif
- }
- simple_unlock(&vp->v_interlock);
+ cache_purge(vp);
AFS_GLOCK();
+ vdrop(vp);
+
return 0;
}
AFS_GUNLOCK();
tries = 5;
vp = AFSTOV(avc);
+
+ /*
+ * I don't understand this. Why not just call vm_object_page_clean()
+ * and be done with it? I particularly don't understand why we're calling
+ * vget() here. Is there some reason to believe that the vnode might
+ * be being recycled at this point? I don't think there's any need for
+ * this loop, either -- if we keep the vnode locked all the time,
+ * that and the object lock will prevent any new pages from appearing.
+ * The loop is what causes the race condition. -GAW
+ */
do {
anyio = 0;
- simple_lock(&vp->v_interlock);
- if (VOP_GETVOBJECT(vp, &obj) == 0 && (obj->flags & OBJ_MIGHTBEDIRTY)) {
-#ifdef AFS_FBSD50_ENV
- if (!vget(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, curthread)) {
-#else
- if (!vget
- (vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ,
- curproc)) {
-#endif
- if (VOP_GETVOBJECT(vp, &obj) == 0) {
- vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
- anyio = 1;
+
+ obj = vp->v_object;
+ if (obj != NULL && obj->flags & OBJ_MIGHTBEDIRTY) {
+ if (!vget(vp, LK_EXCLUSIVE | LK_RETRY, curthread)) {
+ obj = vp->v_object;
+ if (obj != NULL) {
+ AFS_VM_OBJECT_WLOCK(obj);
+ vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
+ AFS_VM_OBJECT_WUNLOCK(obj);
+ anyio = 1;
+ }
+ vput(vp);
}
- vput(vp);
}
- } else
- simple_unlock(&vp->v_interlock);
} while (anyio && (--tries > 0));
AFS_GLOCK();
ObtainWriteLock(&avc->lock, 94);
* be some pages around when we return, newly created by concurrent activity.
*/
void
-osi_VM_TryToSmush(struct vcache *avc, struct AFS_UCRED *acred, int sync)
+osi_VM_TryToSmush(struct vcache *avc, afs_ucred_t *acred, int sync)
{
struct vnode *vp;
- struct vm_object *obj;
- int anyio, tries;
+ int tries, code;
+ int islocked;
- ReleaseWriteLock(&avc->lock);
- AFS_GUNLOCK();
- tries = 5;
vp = AFSTOV(avc);
- do {
- anyio = 0;
- simple_lock(&vp->v_interlock);
- if (VOP_GETVOBJECT(vp, &obj) == 0 && (obj->flags & OBJ_MIGHTBEDIRTY)) {
-#ifdef AFS_FBSD50_ENV
- if (!vget(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, curthread)) {
-#else
- if (!vget
- (vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ,
- curproc)) {
-#endif
- if (VOP_GETVOBJECT(vp, &obj) == 0) {
- vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
- anyio = 1;
- }
- vput(vp);
- }
- } else
- simple_unlock(&vp->v_interlock);
- } while (anyio && (--tries > 0));
- simple_lock(&vp->v_interlock);
- if (VOP_GETVOBJECT(vp, &obj) == 0) {
- vm_object_page_remove(obj, 0, 0, FALSE);
+
+ VI_LOCK(vp);
+ if (vp->v_iflag & VI_DOOMED) {
+ VI_UNLOCK(vp);
+ return;
}
- simple_unlock(&vp->v_interlock);
- /*vinvalbuf(AFSTOV(avc),0, NOCRED, curproc, 0,0); */
- AFS_GLOCK();
- ObtainWriteLock(&avc->lock, 59);
+ VI_UNLOCK(vp);
+
+ islocked = islocked_vnode(vp);
+ if (islocked == LK_EXCLOTHER)
+ panic("Trying to Smush over someone else's lock");
+ else if (islocked == LK_SHARED) {
+ afs_warn("Trying to Smush with a shared lock");
+ lock_vnode(vp, LK_UPGRADE);
+ } else if (!islocked)
+ lock_vnode(vp, LK_EXCLUSIVE);
+
+ if (vp->v_bufobj.bo_object != NULL) {
+ AFS_VM_OBJECT_WLOCK(vp->v_bufobj.bo_object);
+ /*
+ * Do we really want OBJPC_SYNC? OBJPC_INVAL would be
+ * faster, if invalidation is really what we are being
+ * asked to do. (It would make more sense, too, since
+ * otherwise this function is practically identical to
+ * osi_VM_StoreAllSegments().) -GAW
+ */
+
+ /*
+ * Dunno. We no longer resemble osi_VM_StoreAllSegments,
+ * though maybe that's wrong, now. And OBJPC_SYNC is the
+ * common thing in 70 file systems, it seems. Matt.
+ */
+
+ vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
+ AFS_VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object);
+ }
+
+ tries = 5;
+ code = osi_vinvalbuf(vp, V_SAVE, PCATCH, 0);
+ while (code && (tries > 0)) {
+ afs_warn("TryToSmush retrying vinvalbuf");
+ code = osi_vinvalbuf(vp, V_SAVE, PCATCH, 0);
+ --tries;
+ }
+ if (islocked == LK_SHARED)
+ lock_vnode(vp, LK_DOWNGRADE);
+ else if (!islocked)
+ unlock_vnode(vp);
}
/* Purge VM for a file when its callback is revoked.
* Locking: No lock is held, not even the global lock.
*/
void
-osi_VM_FlushPages(struct vcache *avc, struct AFS_UCRED *credp)
+osi_VM_FlushPages(struct vcache *avc, afs_ucred_t *credp)
{
struct vnode *vp;
struct vm_object *obj;
vp = AFSTOV(avc);
- simple_lock(&vp->v_interlock);
- if (VOP_GETVOBJECT(vp, &obj) == 0) {
+ ASSERT_VOP_LOCKED(vp, __func__);
+ obj = vp->v_object;
+ if (obj != NULL) {
+ AFS_VM_OBJECT_WLOCK(obj);
vm_object_page_remove(obj, 0, 0, FALSE);
+ AFS_VM_OBJECT_WUNLOCK(obj);
}
- simple_unlock(&vp->v_interlock);
- /*vinvalbuf(AFSTOV(avc),0, NOCRED, curproc, 0,0); */
+ osi_vinvalbuf(vp, 0, 0, 0);
}
/* Purge pages beyond end-of-file, when truncating a file.
* it only works on Solaris.
*/
void
-osi_VM_Truncate(struct vcache *avc, int alen, struct AFS_UCRED *acred)
+osi_VM_Truncate(struct vcache *avc, int alen, afs_ucred_t *acred)
{
vnode_pager_setsize(AFSTOV(avc), alen);
}
git://git.openafs.org / openafs.git / blobdiff