Changeset 1874 in vbox for trunk/src/VBox

Timestamp:

Apr 3, 2007 11:00:09 AM (18 years ago)

Author:

vboxsync

Message:

Main: Fixed: Simultaneous usage of immutable VDIs by more than one running VM was not possible.

Location:

trunk/src/VBox

Files:

• Devices/Storage/VBoxHDD.cpp (modified) (1 diff)
• Main/ConsoleImpl.cpp (modified) (1 diff)
• Main/HardDiskImpl.cpp (modified) (6 diffs)
• Main/include/HardDiskImpl.h (modified) (1 diff)

trunk/src/VBox/Devices/Storage/VBoxHDD.cpp

@@ -347 +347 @@
                                     N_("VHDD: Configuration error: Querying \"Path\" as string failed"));
 
-        rc = CFGMR3QueryBool(pCfgHandle, "ReadOnly", &fReadOnly);
+        rc = CFGMR3QueryBool(pCurNode, "ReadOnly", &fReadOnly);
         if (rc == VERR_CFGM_VALUE_NOT_FOUND)
             fReadOnly = false;

trunk/src/VBox/Main/ConsoleImpl.cpp

@@ -4869 +4869 @@
                 rc = CFGMR3InsertString(pCur,  "Path", psz);                            RC_CHECK();
                 STR_FREE();
+                rc = CFGMR3InsertInteger(pCur, "ReadOnly", 1);                          RC_CHECK();
 
                 /* next */

trunk/src/VBox/Main/HardDiskImpl.cpp

@@ -567 +567 @@
  *  in the first place.
  *
- *  When @a aCheckBusy is true, this method checks that mBusy = false and
- *  mReaders = 0 (and returns an appropriate error if not). This lets
- *  reimplementations successfully call setBusy() to lock the disk for the
- *  duration of the check if they need. Note that in this case, the
- *  reimplementation must enter the object lock before calling this method
- *  and not leave it before calling setBusy() to avoid race condition.
- *
- *  @param aAccessError On output, a null string indicates the hard disk is
- *                      accessible, otherwise contains a message describing
- *                      the reason of inaccessibility.
- *  @param aCheckBusy   Whether to do the busy check or not.
+ *  When @a aCheckBusy is true, this method checks that mBusy = false (and
+ *  returns an appropriate error if not). This lets reimplementations
+ *  successfully call addReader() after getBaseAccessible() succeeds to
+ *  reference the disk and protect it from being modified or deleted before
+ *  the remaining check steps are done. Note that in this case, the
+ *  reimplementation must enter the object lock before calling this method and
+ *  must not leave it before calling addReader() to avoid race condition.
+ *
+ *  When @a aCheckReaders is true, this method checks that mReaders = 0 (and
+ *  returns an appropriate error if not). When set to true together with
+ *  @a aCheckBusy, this lets reimplementations successfully call setBusy() after
+ *  getBaseAccessible() succeeds to lock the disk and make sure nobody is
+ *  referencing it until the remaining check steps are done. Note that in this
+ *  case, the reimplementation must enter the object lock before calling this
+ *  method and must not leave it before calling setBusy() to avoid race
+ *  condition.
+ *
+ *  @param aAccessError     On output, a null string indicates the hard disk is
+ *                          accessible, otherwise contains a message describing
+ *                          the reason of inaccessibility.
+ *  @param aCheckBusy       Whether to do the busy check or not.
+ *  @param aCheckReaders    Whether to do readers check or not.
  */
 HRESULT HardDisk::getBaseAccessible (Bstr &aAccessError,
-                                     bool aCheckBusy /* = false */)
+                                     bool aCheckBusy /* = false */,
+                                     bool aCheckReaders /* = false */)
 {
     AutoLock alock (this);
@@ -594 +606 @@
                 tr ("Hard disk '%ls' is being exclusively used by another task"),
                 toString().raw());
+            return S_OK;
         }
-        else if (mReaders > 0)
+    }
+
+    if (aCheckReaders)
+    {
+        if (mReaders > 0)
         {
             aAccessError = Utf8StrFmt (
                 tr ("Hard disk '%ls' is being used by another task (%d readers)"),
                 toString().raw(), mReaders);
+            return S_OK;
         }
     }
@@ -2310 +2328 @@
     ComAssertRCRet (vrc, E_FAIL);
 
-    /* go to Busy state to prevent any concurrent modifications
+    /* Reference the disk to prevent any concurrent modifications
      * after releasing the lock below (to unblock getters before 
-     * a lengthy operation) */
-    setBusy();
+     * a lengthy operation). */
+    addReader();
 
     alock.leave();
@@ -2415 +2433 @@
     alock.enter();
     
-    /* remove the busy flag */
-    clearBusy();
+    /* remove the reference */
+    releaseReader();
     
     if (FAILED (rc) || VBOX_FAILURE (vrc) || !errMsg.isNull())
@@ -3909 +3927 @@
     ComAssertRCRet (vrc, E_FAIL);
 
-    /* go to Busy state to prevent any concurrent modifications
+    /* Reference the disk to prevent any concurrent modifications
      * after releasing the lock below (to unblock getters before 
-     * a lengthy operation) */
-    setBusy();
+     * a lengthy operation). */
+    addReader();
 
     alock.leave();
@@ -4020 +4038 @@
     alock.enter();
     
-    /* remove the busy flag */
-    clearBusy();
+    /* remove the reference */
+    releaseReader();
     
     if (FAILED (rc) || VBOX_FAILURE (vrc) || !errMsg.isNull())

trunk/src/VBox/Main/include/HardDiskImpl.h

@@ -129 +129 @@
     ComObjPtr <HardDisk> root() const;
 
-    HRESULT getBaseAccessible (Bstr &aAccessError, bool aCheckBusy = false);
+    HRESULT getBaseAccessible (Bstr &aAccessError, bool aCheckBusy = false,
+                               bool aCheckReaders = false);
 
     // virtual methods that need to be [re]implemented by every subclass