Index: /trunk/include/VBox/pdmblkcache.h =================================================================== --- /trunk/include/VBox/pdmblkcache.h (revision 35161) +++ /trunk/include/VBox/pdmblkcache.h (revision 35162) @@ -310,4 +310,23 @@ */ VMMR3DECL(void) PDMR3BlkCacheIoXferComplete(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEIOXFER hIoXfer, int rcIoXfer); + +/** + * Suspends the block cache. The cache waits until all I/O transfers completed + * and stops to enqueue new requests after the call returned but will not accept + * reads, write or flushes either. + * + * @returns VBox status code. + * @param pBlkCache The cache instance. + */ +VMMR3DECL(int) PDMR3BlkCacheSuspend(PPDMBLKCACHE pBlkCache); + +/** + * Resumes operation of the block cache. + * + * @returns VBox status code. + * @param pBlkCache The cache instance. + */ +VMMR3DECL(int) PDMR3BlkCacheResume(PPDMBLKCACHE pBlkCache); + /** @} */ Index: /trunk/src/VBox/Devices/Storage/DrvVD.cpp =================================================================== --- /trunk/src/VBox/Devices/Storage/DrvVD.cpp (revision 35161) +++ /trunk/src/VBox/Devices/Storage/DrvVD.cpp (revision 35162) @@ -1897,6 +1897,13 @@ LogFlowFunc(("\n")); PVBOXDISK pThis = PDMINS_2_DATA(pDrvIns, PVBOXDISK); + drvvdSetWritable(pThis); pThis->fErrorUseRuntime = true; + + if (pThis->pBlkCache) + { + int rc = PDMR3BlkCacheResume(pThis->pBlkCache); + AssertRC(rc); + } } @@ -1920,4 +1927,11 @@ LogFlowFunc(("\n")); PVBOXDISK pThis = PDMINS_2_DATA(pDrvIns, PVBOXDISK); + + if (pThis->pBlkCache) + { + int rc = PDMR3BlkCacheSuspend(pThis->pBlkCache); + AssertRC(rc); + } + drvvdSetReadonly(pThis); } Index: /trunk/src/VBox/VMM/PDMBlkCache.cpp =================================================================== --- /trunk/src/VBox/VMM/PDMBlkCache.cpp (revision 35161) +++ /trunk/src/VBox/VMM/PDMBlkCache.cpp (revision 35162) @@ -647,4 +647,9 @@ { uint32_t cbCommitted = 0; + + /* Return if the cache was suspended. */ + if (pBlkCache->fSuspended) + return; + RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT); @@ -683,5 +688,10 @@ AssertMsg(pBlkCache->pCache->cbDirty >= cbCommitted, ("Number of committed bytes exceeds number of dirty bytes\n")); - ASMAtomicSubU32(&pBlkCache->pCache->cbDirty, cbCommitted); + uint32_t cbDirtyOld = ASMAtomicSubU32(&pBlkCache->pCache->cbDirty, cbCommitted); + + /* Reset the commit timer if we don't have any dirty bits. */ + if ( !(cbDirtyOld - cbCommitted) + && pBlkCache->pCache->u32CommitTimeoutMs != 0) + TMTimerStop(pBlkCache->pCache->pTimerCommit); } @@ -752,5 +762,10 @@ /* Prevent committing if the VM was suspended. */ if (RT_LIKELY(!ASMAtomicReadBool(&pCache->fIoErrorVmSuspended))) - fDirtyBytesExceeded = (cbDirty >= pCache->cbCommitDirtyThreshold); + fDirtyBytesExceeded = (cbDirty + pEntry->cbData >= pCache->cbCommitDirtyThreshold); + else if (!cbDirty && pCache->u32CommitTimeoutMs > 0) + { + /* Arm the commit timer. */ + TMTimerSetMillies(pCache->pTimerCommit, pCache->u32CommitTimeoutMs); + } } @@ -788,5 +803,4 @@ pdmBlkCacheCommitDirtyEntries(pCache); - TMTimerSetMillies(pTimer, pCache->u32CommitTimeoutMs); LogFlowFunc(("Entries committed, going to sleep\n")); } @@ -1191,4 +1205,5 @@ && pBlkCache->pszId) { + pBlkCache->fSuspended = false; pBlkCache->pCache = pBlkCacheGlobal; RTListInit(&pBlkCache->ListDirtyNotCommitted); @@ -1203,27 +1218,19 @@ if (pBlkCache->pTree) { - /* Arm the timer if this is the first endpoint. */ - if ( !pBlkCacheGlobal->cRefs - && pBlkCacheGlobal->u32CommitTimeoutMs > 0) - rc = TMTimerSetMillies(pBlkCacheGlobal->pTimerCommit, pBlkCacheGlobal->u32CommitTimeoutMs); - - if (RT_SUCCESS(rc)) - { #ifdef VBOX_WITH_STATISTICS - STAMR3RegisterF(pBlkCacheGlobal->pVM, &pBlkCache->StatWriteDeferred, - STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, - STAMUNIT_COUNT, "Number of deferred writes", - "/PDM/BlkCache/%s/Cache/DeferredWrites", pBlkCache->pszId); + STAMR3RegisterF(pBlkCacheGlobal->pVM, &pBlkCache->StatWriteDeferred, + STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, + STAMUNIT_COUNT, "Number of deferred writes", + "/PDM/BlkCache/%s/Cache/DeferredWrites", pBlkCache->pszId); #endif - /* Add to the list of users. */ - pBlkCacheGlobal->cRefs++; - RTListAppend(&pBlkCacheGlobal->ListUsers, &pBlkCache->NodeCacheUser); - pdmBlkCacheLockLeave(pBlkCacheGlobal); - - *ppBlkCache = pBlkCache; - LogFlowFunc(("returns success\n")); - return VINF_SUCCESS; - } + /* Add to the list of users. */ + pBlkCacheGlobal->cRefs++; + RTListAppend(&pBlkCacheGlobal->ListUsers, &pBlkCache->NodeCacheUser); + pdmBlkCacheLockLeave(pBlkCacheGlobal); + + *ppBlkCache = pBlkCache; + LogFlowFunc(("returns success\n")); + return VINF_SUCCESS; } else @@ -1417,8 +1424,4 @@ pCache->cRefs--; RTListNodeRemove(&pBlkCache->NodeCacheUser); - - if ( !pCache->cRefs - && pCache->u32CommitTimeoutMs > 0) - TMTimerStop(pCache->pTimerCommit); pdmBlkCacheLockLeave(pCache); @@ -1934,4 +1937,7 @@ LogFlowFunc((": pBlkCache=%#p{%s} off=%llu pcSgBuf=%#p cbRead=%u pvUser=%#p\n", pBlkCache, pBlkCache->pszId, off, pcSgBuf, cbRead, pvUser)); + + AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER); + AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE); RTSGBUF SgBuf; @@ -2149,4 +2155,7 @@ LogFlowFunc((": pBlkCache=%#p{%s} off=%llu pcSgBuf=%#p cbWrite=%u pvUser=%#p\n", pBlkCache, pBlkCache->pszId, off, pcSgBuf, cbWrite, pvUser)); + + AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER); + AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE); RTSGBUF SgBuf; @@ -2378,4 +2387,7 @@ LogFlowFunc((": pBlkCache=%#p{%s}\n", pBlkCache, pBlkCache->pszId)); + AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER); + AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE); + /* Commit dirty entries in the cache. */ pdmBlkCacheCommit(pBlkCache); @@ -2539,2 +2551,62 @@ } +/** + * Callback for the AVL do with all routine. Waits for a cachen entry to finish any pending I/O. + * + * @returns IPRT status code. + * @param pNode The node to destroy. + * @param pvUser Opaque user data. + */ +static int pdmBlkCacheEntryQuiesce(PAVLRU64NODECORE pNode, void *pvUser) +{ + PPDMBLKCACHEENTRY pEntry = (PPDMBLKCACHEENTRY)pNode; + PPDMBLKCACHE pBlkCache = pEntry->pBlkCache; + + while (ASMAtomicReadU32(&pEntry->fFlags) & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS) + { + /* Leave the locks to let the I/O thread make progress but reference the entry to prevent eviction. */ + pdmBlkCacheEntryRef(pEntry); + RTSemRWReleaseWrite(pBlkCache->SemRWEntries); + + RTThreadSleep(1); + + /* Re-enter all locks and drop the reference. */ + RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT); + pdmBlkCacheEntryRelease(pEntry); + } + + AssertMsg(!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS), + ("Entry is dirty and/or still in progress fFlags=%#x\n", pEntry->fFlags)); + + return VINF_SUCCESS; +} + +VMMR3DECL(int) PDMR3BlkCacheSuspend(PPDMBLKCACHE pBlkCache) +{ + int rc = VINF_SUCCESS; + LogFlowFunc(("pBlkCache=%#p\n", pBlkCache)); + + AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER); + + ASMAtomicXchgBool(&pBlkCache->fSuspended, true); + + /* Wait for all I/O to complete. */ + RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT); + rc = RTAvlrU64DoWithAll(pBlkCache->pTree, true, pdmBlkCacheEntryQuiesce, NULL); + AssertRC(rc); + RTSemRWReleaseWrite(pBlkCache->SemRWEntries); + + return rc; +} + +VMMR3DECL(int) PDMR3BlkCacheResume(PPDMBLKCACHE pBlkCache) +{ + LogFlowFunc(("pBlkCache=%#p\n", pBlkCache)); + + AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER); + + ASMAtomicXchgBool(&pBlkCache->fSuspended, false); + + return VINF_SUCCESS; +} + Index: /trunk/src/VBox/VMM/PDMBlkCacheInternal.h =================================================================== --- /trunk/src/VBox/VMM/PDMBlkCacheInternal.h (revision 35161) +++ /trunk/src/VBox/VMM/PDMBlkCacheInternal.h (revision 35162) @@ -247,4 +247,8 @@ STAMCOUNTER StatWriteDeferred; #endif + + /** Flag whether the cache was suspended. */ + volatile bool fSuspended; + } PDMBLKCACHE, *PPDMBLKCACHE; #ifdef VBOX_WITH_STATISTICS