X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/fa4905b191e0d16b0fffd53bd565eca71d01fae0..d12e16782ebf8bb779633dff9e14486293bf6d07:/bsd/kern/ubc_subr.c

diff --git a/bsd/kern/ubc_subr.c b/bsd/kern/ubc_subr.c
index c82fd94a2..47cb041ab 100644
--- a/bsd/kern/ubc_subr.c
+++ b/bsd/kern/ubc_subr.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999-2001 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
@@ -55,7 +55,7 @@
 #undef assert()
 #endif
 #define assert(cond)    \
-    if (!(cond)) panic("%s:%d (%s)", __FILE__, __LINE__, # cond)
+    ((void) ((cond) ? 0 : panic("%s:%d (%s)", __FILE__, __LINE__, # cond)))
 #else
 #include <kern/assert.h>
 #endif /* DIAGNOSTIC */
@@ -78,6 +78,62 @@ ubc_unlock(struct vnode *vp)
 	simple_unlock(&vp->v_interlock);
 }
 
+/*
+ * Serialize the requests to the VM
+ * Returns:
+ *		0	-	Failure
+ *		1	-	Sucessful in acquiring the lock
+ *		2	-	Sucessful in acquiring the lock recursively
+ *				do not call ubc_unbusy()
+ *				[This is strange, but saves 4 bytes in struct ubc_info]
+ */
+static int
+ubc_busy(struct vnode *vp)
+{
+	register struct ubc_info	*uip;
+
+	if (!UBCINFOEXISTS(vp))
+		return (0);
+
+	uip = vp->v_ubcinfo;
+
+	while (ISSET(uip->ui_flags, UI_BUSY)) {
+
+		if (uip->ui_owner == (void *)current_thread())
+			return (2);
+
+		SET(uip->ui_flags, UI_WANTED);
+		(void) tsleep((caddr_t)&vp->v_ubcinfo, PINOD, "ubcbusy", 0);
+
+		if (!UBCINFOEXISTS(vp))
+			return (0);
+	}
+	uip->ui_owner = (void *)current_thread();
+
+	SET(uip->ui_flags, UI_BUSY);
+
+	return (1);
+}
+
+static void
+ubc_unbusy(struct vnode *vp)
+{
+	register struct ubc_info	*uip;
+
+	if (!UBCINFOEXISTS(vp)) {
+		wakeup((caddr_t)&vp->v_ubcinfo);
+		return;
+	}
+	uip = vp->v_ubcinfo;
+	CLR(uip->ui_flags, UI_BUSY);
+	uip->ui_owner = (void *)NULL;
+
+	if (ISSET(uip->ui_flags, UI_WANTED)) {
+		CLR(uip->ui_flags, UI_WANTED);
+		wakeup((caddr_t)&vp->v_ubcinfo);
+	}
+}
+
 /*
  *	Initialization of the zone for Unified Buffer Cache.
  */
@@ -139,6 +195,7 @@ ubc_info_init(struct vnode *vp)
 		uip->ui_refcount = 1;
 		uip->ui_size = 0;
 		uip->ui_mapped = 0;
+		uip->ui_owner = (void *)NULL;
 		ubc_lock(vp);
 	}
 #if DIAGNOSTIC
@@ -232,10 +289,20 @@ ubc_info_free(struct ubc_info *uip)
 void
 ubc_info_deallocate(struct ubc_info *uip)
 {
+
 	assert(uip->ui_refcount > 0);
 
-    if (uip->ui_refcount-- == 1)
+    if (uip->ui_refcount-- == 1) {
+		struct vnode *vp;
+
+		vp = uip->ui_vnode;
+		if (ISSET(uip->ui_flags, UI_WANTED)) {
+			CLR(uip->ui_flags, UI_WANTED);
+			wakeup((caddr_t)&vp->v_ubcinfo);
+		}
+
 		ubc_info_free(uip);
+	}
 }
 
 /*
@@ -339,12 +406,16 @@ ubc_uncache(struct vnode *vp)
 {
 	kern_return_t kret;
 	struct ubc_info *uip;
+	int    recursed;
 	memory_object_control_t control;
 	memory_object_perf_info_data_t   perf;
 
 	if (!UBCINFOEXISTS(vp))
 		return (0);
 
+	if ((recursed = ubc_busy(vp)) == 0)
+		return (0);
+
 	uip = vp->v_ubcinfo;
 
 	assert(uip != UBC_INFO_NULL);
@@ -372,11 +443,15 @@ ubc_uncache(struct vnode *vp)
 	if (kret != KERN_SUCCESS) {
 		printf("ubc_uncache: memory_object_change_attributes_named "
 			"kret = %d", kret);
+		if (recursed == 1)
+			ubc_unbusy(vp);
 		return (0);
 	}
 
 	ubc_release_named(vp);
 
+	if (recursed == 1)
+		ubc_unbusy(vp);
 	return (1);
 }
 
@@ -506,15 +581,16 @@ memory_object_control_t
 ubc_getobject(struct vnode *vp, int flags)
 {
 	struct ubc_info *uip;
+	int    recursed;
 	memory_object_control_t control;
 
-	uip = vp->v_ubcinfo;
-
 	if (UBCINVALID(vp))
 		return (0);
 
-	ubc_lock(vp);
+	if ((recursed = ubc_busy(vp)) == 0)
+		return (0);
 
+	uip = vp->v_ubcinfo;
 	control = uip->ui_control;
 
 	if ((flags & UBC_HOLDOBJECT) && (!ISSET(uip->ui_flags, UI_HASOBJREF))) {
@@ -523,19 +599,21 @@ ubc_getobject(struct vnode *vp, int flags)
 		 * Take a temporary reference on the ubc info so that it won't go
 		 * away during our recovery attempt.
 		 */
+		ubc_lock(vp);
 		uip->ui_refcount++;
 		ubc_unlock(vp);
 		if (memory_object_recover_named(control, TRUE) == KERN_SUCCESS) {
-			ubc_lock(vp);
 			SET(uip->ui_flags, UI_HASOBJREF);
-			ubc_unlock(vp);
 		} else {
 			control = MEMORY_OBJECT_CONTROL_NULL;
 		}
+		if (recursed == 1)
+			ubc_unbusy(vp);
 		ubc_info_deallocate(uip);
 
 	} else {
-		ubc_unlock(vp);
+		if (recursed == 1)
+			ubc_unbusy(vp);
 	}
 
 	return (control);
@@ -770,15 +848,16 @@ int
 ubc_hold(struct vnode *vp)
 {
 	struct ubc_info *uip;
+	int    recursed;
 	memory_object_control_t object;
 
 	if (UBCINVALID(vp))
 		return (0);
 
-	if (!UBCINFOEXISTS(vp)) {
+	if ((recursed = ubc_busy(vp)) == 0) {
 		/* must be invalid or dying vnode */
 		assert(UBCINVALID(vp) ||
-			   ((vp->v_flag & VXLOCK) || (vp->v_flag & VTERMINATE)));
+			((vp->v_flag & VXLOCK) || (vp->v_flag & VTERMINATE)));
 		return (0);
 	}
 
@@ -787,21 +866,23 @@ ubc_hold(struct vnode *vp)
 
 	ubc_lock(vp);
 	uip->ui_refcount++;
+	ubc_unlock(vp);
 
 	if (!ISSET(uip->ui_flags, UI_HASOBJREF)) {
-		ubc_unlock(vp);
-		if (memory_object_recover_named(uip->ui_control, TRUE) != KERN_SUCCESS) {
+		if (memory_object_recover_named(uip->ui_control, TRUE)
+			!= KERN_SUCCESS) {
+			if (recursed == 1)
+				ubc_unbusy(vp);
 			ubc_info_deallocate(uip);
 			return (0);
 		}
-		ubc_lock(vp);
 		SET(uip->ui_flags, UI_HASOBJREF);
-		ubc_unlock(vp);
-	} else {
-		ubc_unlock(vp);
 	}
+	if (recursed == 1)
+		ubc_unbusy(vp);
 
 	assert(uip->ui_refcount > 0);
+
 	return (1);
 }
 
@@ -872,28 +953,30 @@ int
 ubc_release_named(struct vnode *vp)
 {
 	struct ubc_info *uip;
+	int    recursed;
 	memory_object_control_t control;
-	kern_return_t kret;
+	kern_return_t kret = KERN_FAILURE;
 
 	if (UBCINVALID(vp))
 		return (0);
 
-	if (!UBCINFOEXISTS(vp))
+	if ((recursed = ubc_busy(vp)) == 0)
 		return (0);
-
 	uip = vp->v_ubcinfo;
 
 	/* can not release held or mapped vnodes */
 	if (ISSET(uip->ui_flags, UI_HASOBJREF) && 
-	    (uip->ui_refcount == 1) && !uip->ui_mapped) {
+		(uip->ui_refcount == 1) && !uip->ui_mapped) {
 		control = uip->ui_control;
 		assert(control);
 		CLR(uip->ui_flags, UI_HASOBJREF);
 		kret = memory_object_release_name(control,
 				MEMORY_OBJECT_RESPECT_CACHE);
-		return ((kret != KERN_SUCCESS) ? 0 : 1);
-	} else 
-		return (0);
+	}
+
+	if (recursed == 1)
+		ubc_unbusy(vp);
+	return ((kret != KERN_SUCCESS) ? 0 : 1);
 }
 
 /*
@@ -1023,6 +1106,13 @@ ubc_isinuse(struct vnode *vp, int tookref)
 	if (!UBCINFOEXISTS(vp))
 		return (0);
 
+	if (tookref == 0) {
+		printf("ubc_isinuse: called without a valid reference"
+		    ": v_tag = %d\v", vp->v_tag);
+		vprint("ubc_isinuse", vp);
+		return (0);
+	}
+
 	if (vp->v_usecount > busycount)
 		return (1);