Changeset 27557 in vbox for trunk/src/VBox/VMM

Timestamp:

Mar 20, 2010 9:14:43 PM (15 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

59075

Message:

I/O cache: Increase the endpoint size for every appending write, even if it isn't immediately written to the file (delay in the cache). Fixes data corruption when appending data in VMDK images

Location:

trunk/src/VBox/VMM

Files:

• PDMAsyncCompletionFile.cpp (modified) (4 diffs)
• PDMAsyncCompletionFileCache.cpp (modified) (3 diffs)
• PDMAsyncCompletionFileInternal.h (modified) (1 diff)

trunk/src/VBox/VMM/PDMAsyncCompletionFile.cpp

@@ -868 +868 @@
                 PPDMACEPFILEMGR pAioMgr = NULL;
 
+                pEpFile->cbEndpoint     = pEpFile->cbFile;
                 pEpFile->pTasksFreeTail = pEpFile->pTasksFreeHead;
                 pEpFile->cTasksCached   = 0;
@@ -970 +971 @@
     AssertRC(rc);
 
+    /* endpoint and real file size should better be equal now. */
+    AssertMsg(pEpFile->cbFile == pEpFile->cbEndpoint,
+              ("Endpoint and real file size should match now!\n"));
+
     /*
      * If the async I/O manager is in failsafe mode this is the only endpoint
@@ -1051 +1056 @@
     STAM_PROFILE_ADV_STOP(&pEpFile->StatWrite, Write);
 
+    /* Increase endpoint size. */
+    if (   RT_SUCCESS(rc)
+        && ((uint64_t)off + cbWrite) > pEpFile->cbEndpoint)
+        ASMAtomicWriteU64(&pEpFile->cbEndpoint, (uint64_t)off + cbWrite);
+
     return rc;
 }
@@ -1088 +1098 @@
     PPDMASYNCCOMPLETIONENDPOINTFILE pEpFile = (PPDMASYNCCOMPLETIONENDPOINTFILE)pEndpoint;
 
-    *pcbSize = ASMAtomicReadU64(&pEpFile->cbFile);
+    *pcbSize = ASMAtomicReadU64(&pEpFile->cbEndpoint);
 
     return VINF_SUCCESS;

trunk/src/VBox/VMM/PDMAsyncCompletionFileCache.cpp

@@ -1666 +1666 @@
 
             AssertMsg(   (off >= pEntryNew->Core.Key)
-                      && (off + (RTFOFF)cb <= pEntryNew->Core.Key + pEntryNew->Core.KeyLast + 1),
+                      && (off + (RTFOFF)*pcbData <= pEntryNew->Core.KeyLast + 1),
                       ("Overflow in calculation off=%RTfoff OffsetAligned=%RTfoff\n",
                        off, pEntryNew->Core.Key));
@@ -2166 +2166 @@
             cbWrite -= cbToWrite;
 
-            STAM_COUNTER_INC(&pCache->cMisses);
-
             if (pEntryNew)
             {
                 RTFOFF offDiff = off - pEntryNew->Core.Key;
+
+                STAM_COUNTER_INC(&pCache->cHits);
 
                 /*
@@ -2209 +2209 @@
                 LogFlow(("Couldn't evict %u bytes from the cache. Remaining request will be passed through\n", cbToWrite));
 
+                STAM_COUNTER_INC(&pCache->cMisses);
+
                 pdmacFileEpCacheRequestPassthrough(pEndpoint, pTask,
                                                    &IoMemCtx, off, cbToWrite,

trunk/src/VBox/VMM/PDMAsyncCompletionFileInternal.h

@@ -518 +518 @@
     /** File handle. */
     RTFILE                                 File;
-    /** Size of the underlying file.
-     * Updated while data is appended. */
+    /** Size of the endpoint.
+     * Updated while data is appended even if it is
+     * only in the cache yet and not written to the file.
+     */
+    volatile uint64_t                      cbEndpoint;
+    /**
+     * Real size of the file. Only updated if
+     * data is appended.
+     */
     volatile uint64_t                      cbFile;
     /** Flag whether caching is enabled for this file. */