Changeset 73858 in vbox for trunk/src/VBox/Main/src-server

Timestamp:

Aug 23, 2018 1:35:07 PM (6 years ago)

Author:

vboxsync

Message:

Main: bugref:8929: Medium::setDescription has been reordered to avoid redudant lock acquire/release operations

File:

• trunk/src/VBox/Main/src-server/MediumImpl.cpp (modified) (2 diffs)

trunk/src/VBox/Main/src-server/MediumImpl.cpp

@@ -1600 +1600 @@
         autoCaller.release();
 
-        // locking: we need the tree lock first because we access parent pointers
-        // and we need to write-lock the media involved
-        AutoWriteLock treeLock(m->pVirtualBox->i_getMediaTreeLockHandle() COMMA_LOCKVAL_SRC_POS);
-
-        autoCaller.add();
-        AssertComRCThrowRC(autoCaller.rc());
-
-        AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+        // to avoid redundant locking, which just takes a time, just call required functions.
+        // the error will be just stored and will be reported after locks will be acquired again
+
+        const char *pszError = NULL;
+
 
         /* Build the lock list. */
-        alock.release();
-        autoCaller.release();
-        treeLock.release();
         rc = i_createMediumLockList(true /* fFailIfInaccessible */,
                                     this /* pToLockWrite */,
@@ -1618 +1612 @@
                                     NULL,
                                     *pMediumLockList);
-        treeLock.acquire();
+        if (FAILED(rc))
+        {
+            pszError = tr("Failed to create medium lock list for '%s'");
+        }
+        else
+        {
+            rc = pMediumLockList->Lock();
+            if (FAILED(rc))
+                pszError = tr("Failed to lock media '%s'");
+        }
+
+        // locking: we need the tree lock first because we access parent pointers
+        // and we need to write-lock the media involved
+        AutoWriteLock treeLock(m->pVirtualBox->i_getMediaTreeLockHandle() COMMA_LOCKVAL_SRC_POS);
+
         autoCaller.add();
         AssertComRCThrowRC(autoCaller.rc());
-        alock.acquire();
+
+        AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
 
         if (FAILED(rc))
-        {
-            throw setError(rc,
-                           tr("Failed to create medium lock list for '%s'"),
-                           i_getLocationFull().c_str());
-        }
-
-        alock.release();
-        autoCaller.release();
-        treeLock.release();
-        rc = pMediumLockList->Lock();
-        treeLock.acquire();
-        autoCaller.add();
-        AssertComRCThrowRC(autoCaller.rc());
-        alock.acquire();
-
-        if (FAILED(rc))
-        {
-            throw setError(rc,
-                           tr("Failed to lock media '%s'"),
-                           i_getLocationFull().c_str());
-        }
+            throw setError(rc, pszError, i_getLocationFull().c_str());
 
         /* Set a new description */
-        if (SUCCEEDED(rc))
-        {
-            m->strDescription = aDescription;
-        }
+        m->strDescription = aDescription;
 
         // save the settings