1 files changed, 20 insertions, 63 deletions

diff --git a/kernel/vm/shadow.c b/kernel/vm/shadow.c
index 91b1fce..06cf20d 100644
--- a/kernel/vm/shadow.c
+++ b/kernel/vm/shadow.c
@@ -71,6 +71,7 @@ mobj_t *shadow_create(mobj_t *shadowed)
     }
 
     // initialize the mobj_shadow_t
+    so->shadowed = shadowed;
     
     // set the bottom_mobj based on the two cases
     if (shadowed->mo_type == MOBJ_SHADOW)
@@ -82,12 +83,11 @@ mobj_t *shadow_create(mobj_t *shadowed)
         so->bottom_mobj = shadowed;
     }
     // init the other fields
-    so->shadowed = shadowed;
-    mobj_init(&so->mobj, MOBJ_SHADOW, &shadow_mobj_ops);
     mobj_ref(so->shadowed);
     mobj_ref(so->bottom_mobj);
 
-    // lock the shadow object
+    // init and lock the shadow object
+    mobj_init(&so->mobj, MOBJ_SHADOW, &shadow_mobj_ops);
     mobj_lock(&so->mobj);
 
     // return the shadow object
@@ -110,52 +110,7 @@ mobj_t *shadow_create(mobj_t *shadowed)
  */
 void shadow_collapse(mobj_t *o)
 {
-    // NOT_YET_IMPLEMENTED("VM: shadow_collapse");
-
-    // get the mobj_shadow_t and it's mobj
-    mobj_shadow_t *so = MOBJ_TO_SO(o);
-    mobj_t *iter = so->shadowed;
-    // iterate through the shadow chain
-    while (iter && so->shadowed->mo_type == MOBJ_SHADOW)
-    {
-        // check to see if the refcount is not 1. if so, continue to next shadowed object
-        if (so->shadowed->mo_refcount != 1)
-        {
-            iter = so->shadowed;
-            continue;
-        }
-        // else, go over the shadowed object's pframes
-
-        // iterate through the pframes
-        mobj_lock(&so->shadowed);
-        list_iterate(&so->shadowed->mo_pframes, pframe, pframe_t, pf_link)
-        {
-            // get the pframe from the shadow object
-            pframe_t *spf = NULL;
-
-            mobj_lock(iter); // lock before getting the pframe
-            mobj_find_pframe(o, pframe->pf_pagenum, &spf);
-            mobj_unlock(iter);
-
-            // check if the pframe is not in the shadow object when migrating
-            if (spf == NULL)
-            {
-                // if not, remove the pframe from the shadowed object 
-                // and insert it into out iterated shadow object
-                list_remove(&pframe->pf_link);
-                list_insert_tail(&iter->mo_pframes, &pframe->pf_link);
-            }
-            else
-            {
-                // if it is, release the pframe we found
-                pframe_release(&spf);
-            }
-        }
-
-        // put locked the shadowed object after iterating through it
-        mobj_put_locked(&so->shadowed);
-        // FIXME: this is probably wrong
-    }
+    NOT_YET_IMPLEMENTED("VM: shadow_collapse");
 }
 
 /*
@@ -210,7 +165,7 @@ static long shadow_get_pframe(mobj_t *o, size_t pagenum, long forwrite,
     while (iter && iter->mo_type == MOBJ_SHADOW)
     {
         mobj_lock(iter);
-        mobj_find_pframe(o, pagenum, &pf);
+        mobj_find_pframe(iter, pagenum, &pf);
         mobj_unlock(iter);
         if (pf)
         {
@@ -218,14 +173,15 @@ static long shadow_get_pframe(mobj_t *o, size_t pagenum, long forwrite,
             return 0;
         }
         // update the iterator
-        iter = MOBJ_TO_SO(iter)->shadowed;
+        so = MOBJ_TO_SO(iter);
+        iter = so->shadowed;
     }
 
     // if no shadow objects have the page, call mobj_get_pframe() to get the page from the bottom object
     // at this point, iter is the bottom object
-    mobj_lock(iter);
-    long ret = mobj_get_pframe(iter, pagenum, forwrite, pfp);
-    mobj_unlock(iter);
+    mobj_lock(so->bottom_mobj);
+    long ret = mobj_get_pframe(so->bottom_mobj, pagenum, forwrite, pfp);
+    mobj_unlock(so->bottom_mobj);
     return ret;
 }
 
@@ -252,7 +208,7 @@ static long shadow_get_pframe(mobj_t *o, size_t pagenum, long forwrite,
  */
 static long shadow_fill_pframe(mobj_t *o, pframe_t *pf)
 {
-    // NOT_YET_IMPLEMENTED("VM: shadow_fill_pframe");
+    // NOT_YET_IMPLEMENTEDshadow_fill_pframe");
 
     // get the mobj_shadow_t
     mobj_shadow_t *so = MOBJ_TO_SO(o);
@@ -263,7 +219,7 @@ static long shadow_fill_pframe(mobj_t *o, pframe_t *pf)
         // get the pframe from the shadow object
         pframe_t *spf = NULL;
         mobj_lock(iter);
-        mobj_find_pframe(o, pf->pf_pagenum, &spf);
+        mobj_find_pframe(iter, pf->pf_pagenum, &spf);
         mobj_unlock(iter);
 
         // if the pframe is found, copy the contents into pf 
@@ -276,19 +232,20 @@ static long shadow_fill_pframe(mobj_t *o, pframe_t *pf)
         }
 
         // update the iterator
-        iter = MOBJ_TO_SO(iter)->shadowed;
+        so = MOBJ_TO_SO(iter);
+        iter = so->shadowed;
     }
 
     // if none of the shadow objects have a copy of the frame, use mobj_get_pframe on the bottom object
     pframe_t *spf = NULL;
-    mobj_lock(iter);
-    long ret = mobj_get_pframe(iter, pf->pf_pagenum, 0, &spf);
-    mobj_unlock(iter);
+    mobj_lock(so->bottom_mobj);
+    long ret = mobj_get_pframe(so->bottom_mobj, pf->pf_pagenum, 0, &spf);
+    mobj_unlock(so->bottom_mobj);
     // check if the operation was sucessful, memcpy the contents into pf
     // and release the pframe
-    if (ret == 0)
+    if (ret >= 0)
     {
-        memcpy(pf->pf_addr, pf->pf_addr, PAGE_SIZE);
+        memcpy(pf->pf_addr, spf->pf_addr, PAGE_SIZE);
         pframe_release(&spf);
     }
 
@@ -336,4 +293,4 @@ static void shadow_destructor(mobj_t *o)
 
     // free the slab
     slab_obj_free(shadow_allocator, so);
-}
+}
\ No newline at end of file