QCOW.cpp@ 44232

Last change on this file since 44232 was 44232, checked in by vboxsync, 12 years ago
Storage: Fix regression introduced when adding VD_OPEN_FLAGS_SKIP_CONSISTENCY_CHECKS resulting in non working online merging of snapshots
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1	/* $Id: QCOW.cpp 44232 2013-01-04 14:30:20Z vboxsync $ */
2	/** @file
3	* QCOW - QCOW Disk image.
4	*/
5
6	/*
7	* Copyright (C) 2011 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18	/*******************************************************************************
19	* Header Files *
20	*******************************************************************************/
21	#define LOG_GROUP LOG_GROUP_VD_QCOW
22	#include <VBox/vd-plugin.h>
23	#include <VBox/err.h>
24
25	#include <VBox/log.h>
26	#include <iprt/asm.h>
27	#include <iprt/assert.h>
28	#include <iprt/string.h>
29	#include <iprt/alloc.h>
30	#include <iprt/path.h>
31	#include <iprt/list.h>
32
33	/**
34	* The QCOW backend implements support for the qemu copy on write format (short QCOW)
35	* There is no official specification available but the format is described
36	* at http://people.gnome.org/~markmc/qcow-image-format.html for version 2
37	* and http://people.gnome.org/~markmc/qcow-image-format-version-1.html for version 1.
38	*
39	* Missing things to implement:
40	* - v2 image creation and handling of the reference count table. (Blocker to enable support for V2 images)
41	* - cluster encryption
42	* - cluster compression
43	* - compaction
44	* - resizing
45	*/
46
47	/*******************************************************************************
48	* Structures in a QCOW image, big endian *
49	*******************************************************************************/
50
51	#pragma pack(1)
52	typedef struct QCowHeader
53	{
54	/** Magic value. */
55	uint32_t u32Magic;
56	/** Version of the image. */
57	uint32_t u32Version;
58	/** Version dependent data. */
59	union
60	{
61	/** Version 1. */
62	struct
63	{
64	/** Backing file offset. */
65	uint64_t u64BackingFileOffset;
66	/** Size of the backing file. */
67	uint32_t u32BackingFileSize;
68	/** mtime (Modification time?) - can be ignored. */
69	uint32_t u32MTime;
70	/** Logical size of the image in bytes. */
71	uint64_t u64Size;
72	/** Number of bits in the virtual offset used as a cluster offset. */
73	uint8_t u8ClusterBits;
74	/** Number of bits in the virtual offset used for the L2 index. */
75	uint8_t u8L2Bits;
76	/** Padding because the header is not packed in the original source. */
77	uint16_t u16Padding;
78	/** Used cryptographic method. */
79	uint32_t u32CryptMethod;
80	/** Offset of the L1 table in the image in bytes. */
81	uint64_t u64L1TableOffset;
82	} v1;
83	/** Version 2. */
84	struct
85	{
86	/** Backing file offset. */
87	uint64_t u64BackingFileOffset;
88	/** Size of the backing file. */
89	uint32_t u32BackingFileSize;
90	/** Number of bits in the virtual offset used as a cluster offset. */
91	uint32_t u32ClusterBits;
92	/** Logical size of the image. */
93	uint64_t u64Size;
94	/** Used cryptographic method. */
95	uint32_t u32CryptMethod;
96	/** Size of the L1 table in entries (each 8bytes big). */
97	uint32_t u32L1Size;
98	/** Offset of the L1 table in the image in bytes. */
99	uint64_t u64L1TableOffset;
100	/** Start of the refcount table in the image. */
101	uint64_t u64RefcountTableOffset;
102	/** Size of the refcount table in clusters. */
103	uint32_t u32RefcountTableClusters;
104	/** Number of snapshots in the image. */
105	uint32_t u32NbSnapshots;
106	/** Offset of the first snapshot header in the image. */
107	uint64_t u64SnapshotsOffset;
108	} v2;
109	} Version;
110	} QCowHeader;
111	#pragma pack()
112	/** Pointer to a on disk QCOW header. */
113	typedef QCowHeader *PQCowHeader;
114
115	/** QCOW magic value. */
116	#define QCOW_MAGIC UINT32_C(0x514649fb) /* QFI\0xfb */
117	/** Size of the V1 header. */
118	#define QCOW_V1_HDR_SIZE (48)
119	/** Size of the V2 header. */
120	#define QCOW_V2_HDR_SIZE (72)
121
122	/** Cluster is compressed flag for QCOW images. */
123	#define QCOW_V1_COMPRESSED_FLAG RT_BIT_64(63)
124
125	/** Copied flag for QCOW2 images. */
126	#define QCOW_V2_COPIED_FLAG RT_BIT_64(63)
127	/** Cluster is compressed flag for QCOW2 images. */
128	#define QCOW_V2_COMPRESSED_FLAG RT_BIT_64(62)
129
130
131	/*******************************************************************************
132	* Constants And Macros, Structures and Typedefs *
133	*******************************************************************************/
134
135	/**
136	* QCOW L2 cache entry.
137	*/
138	typedef struct QCOWL2CACHEENTRY
139	{
140	/** List node for the search list. */
141	RTLISTNODE NodeSearch;
142	/** List node for the LRU list. */
143	RTLISTNODE NodeLru;
144	/** Reference counter. */
145	uint32_t cRefs;
146	/** The offset of the L2 table, used as search key. */
147	uint64_t offL2Tbl;
148	/** Pointer to the cached L2 table. */
149	uint64_t *paL2Tbl;
150	} QCOWL2CACHEENTRY, *PQCOWL2CACHEENTRY;
151
152	/** Maximum amount of memory the cache is allowed to use. */
153	#define QCOW_L2_CACHE_MEMORY_MAX (2*_1M)
154
155	/** QCOW default cluster size for image version 2. */
156	#define QCOW2_CLUSTER_SIZE_DEFAULT (64*_1K)
157	/** QCOW default cluster size for image version 1. */
158	#define QCOW_CLUSTER_SIZE_DEFAULT (4*_1K)
159	/** QCOW default L2 table size in clusters. */
160	#define QCOW_L2_CLUSTERS_DEFAULT (1)
161
162	/**
163	* QCOW image data structure.
164	*/
165	typedef struct QCOWIMAGE
166	{
167	/** Image name. */
168	const char *pszFilename;
169	/** Storage handle. */
170	PVDIOSTORAGE pStorage;
171
172	/** Pointer to the per-disk VD interface list. */
173	PVDINTERFACE pVDIfsDisk;
174	/** Pointer to the per-image VD interface list. */
175	PVDINTERFACE pVDIfsImage;
176	/** Error interface. */
177	PVDINTERFACEERROR pIfError;
178	/** I/O interface. */
179	PVDINTERFACEIOINT pIfIo;
180
181	/** Open flags passed by VBoxHD layer. */
182	unsigned uOpenFlags;
183	/** Image flags defined during creation or determined during open. */
184	unsigned uImageFlags;
185	/** Total size of the image. */
186	uint64_t cbSize;
187	/** Physical geometry of this image. */
188	VDGEOMETRY PCHSGeometry;
189	/** Logical geometry of this image. */
190	VDGEOMETRY LCHSGeometry;
191
192	/** Image version. */
193	unsigned uVersion;
194	/** MTime field - used only to preserve value in opened images, unmodified otherwise. */
195	uint32_t MTime;
196
197	/** Filename of the backing file if any. */
198	char *pszBackingFilename;
199	/** Offset of the filename in the image. */
200	uint64_t offBackingFilename;
201	/** Size of the backing filename excluding \0. */
202	uint32_t cbBackingFilename;
203
204	/** Next offset of a new cluster, aligned to sector size. */
205	uint64_t offNextCluster;
206	/** Cluster size in bytes. */
207	uint32_t cbCluster;
208	/** Number of entries in the L1 table. */
209	uint32_t cL1TableEntries;
210	/** Size of an L1 rounded to the next cluster size. */
211	uint32_t cbL1Table;
212	/** Pointer to the L1 table. */
213	uint64_t *paL1Table;
214	/** Offset of the L1 table. */
215	uint64_t offL1Table;
216
217	/** Size of the L2 table in bytes. */
218	uint32_t cbL2Table;
219	/** Number of entries in the L2 table. */
220	uint32_t cL2TableEntries;
221	/** Memory occupied by the L2 table cache. */
222	size_t cbL2Cache;
223	/** The sorted L2 entry list used for searching. */
224	RTLISTNODE ListSearch;
225	/** The LRU L2 entry list used for eviction. */
226	RTLISTNODE ListLru;
227
228	/** Offset of the refcount table. */
229	uint64_t offRefcountTable;
230	/** Size of the refcount table in bytes. */
231	uint32_t cbRefcountTable;
232	/** Number of entries in the refcount table. */
233	uint32_t cRefcountTableEntries;
234	/** Pointer to the refcount table. */
235	uint64_t *paRefcountTable;
236
237	/** Offset mask for a cluster. */
238	uint64_t fOffsetMask;
239	/** Number of bits to shift to get the L1 index. */
240	uint32_t cL1Shift;
241	/** L2 table mask to get the L2 index. */
242	uint64_t fL2Mask;
243	/** Number of bits to shift to get the L2 index. */
244	uint32_t cL2Shift;
245
246	} QCOWIMAGE, *PQCOWIMAGE;
247
248	/**
249	* State of the async cluster allocation.
250	*/
251	typedef enum QCOWCLUSTERASYNCALLOCSTATE
252	{
253	/** Invalid. */
254	QCOWCLUSTERASYNCALLOCSTATE_INVALID = 0,
255	/** L2 table allocation. */
256	QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC,
257	/** Link L2 table into L1. */
258	QCOWCLUSTERASYNCALLOCSTATE_L2_LINK,
259	/** Allocate user data cluster. */
260	QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC,
261	/** Link user data cluster. */
262	QCOWCLUSTERASYNCALLOCSTATE_USER_LINK,
263	/** 32bit blowup. */
264	QCOWCLUSTERASYNCALLOCSTATE_32BIT_HACK = 0x7fffffff
265	} QCOWCLUSTERASYNCALLOCSTATE, *PQCOWCLUSTERASYNCALLOCSTATE;
266
267	/**
268	* Data needed to track async cluster allocation.
269	*/
270	typedef struct QCOWCLUSTERASYNCALLOC
271	{
272	/** The state of the cluster allocation. */
273	QCOWCLUSTERASYNCALLOCSTATE enmAllocState;
274	/** Old image size to rollback in case of an error. */
275	uint64_t offNextClusterOld;
276	/** L1 index to link if any. */
277	uint32_t idxL1;
278	/** L2 index to link, required in any case. */
279	uint32_t idxL2;
280	/** Start offset of the allocated cluster. */
281	uint64_t offClusterNew;
282	/** L2 cache entry if a L2 table is allocated. */
283	PQCOWL2CACHEENTRY pL2Entry;
284	/** Number of bytes to write. */
285	size_t cbToWrite;
286	} QCOWCLUSTERASYNCALLOC, *PQCOWCLUSTERASYNCALLOC;
287
288	/*******************************************************************************
289	* Static Variables *
290	*******************************************************************************/
291
292	/** NULL-terminated array of supported file extensions. */
293	static const VDFILEEXTENSION s_aQCowFileExtensions[] =
294	{
295	{"qcow", VDTYPE_HDD},
296	{"qcow2", VDTYPE_HDD},
297	{NULL, VDTYPE_INVALID}
298	};
299
300	/*******************************************************************************
301	* Internal Functions *
302	*******************************************************************************/
303
304	/**
305	* Return power of 2 or 0 if num error.
306	*
307	* @returns The power of 2 or 0 if the given number is not a power of 2.
308	* @param u32 The number.
309	*/
310	static uint32_t qcowGetPowerOfTwo(uint32_t u32)
311	{
312	if (u32 == 0)
313	return 0;
314	uint32_t uPower2 = 0;
315	while ((u32 & 1) == 0)
316	{
317	u32 >>= 1;
318	uPower2++;
319	}
320	return u32 == 1 ? uPower2 : 0;
321	}
322
323
324	/**
325	* Converts the image header to the host endianess and performs basic checks.
326	*
327	* @returns Whether the given header is valid or not.
328	* @param pHeader Pointer to the header to convert.
329	*/
330	static bool qcowHdrConvertToHostEndianess(PQCowHeader pHeader)
331	{
332	pHeader->u32Magic = RT_BE2H_U32(pHeader->u32Magic);
333	pHeader->u32Version = RT_BE2H_U32(pHeader->u32Version);
334
335	if (pHeader->u32Magic != QCOW_MAGIC)
336	return false;
337
338	if (pHeader->u32Version == 1)
339	{
340	pHeader->Version.v1.u64BackingFileOffset = RT_BE2H_U64(pHeader->Version.v1.u64BackingFileOffset);
341	pHeader->Version.v1.u32BackingFileSize = RT_BE2H_U32(pHeader->Version.v1.u32BackingFileSize);
342	pHeader->Version.v1.u32MTime = RT_BE2H_U32(pHeader->Version.v1.u32MTime);
343	pHeader->Version.v1.u64Size = RT_BE2H_U64(pHeader->Version.v1.u64Size);
344	pHeader->Version.v1.u32CryptMethod = RT_BE2H_U32(pHeader->Version.v1.u32CryptMethod);
345	pHeader->Version.v1.u64L1TableOffset = RT_BE2H_U64(pHeader->Version.v1.u64L1TableOffset);
346	}
347	else if (pHeader->u32Version == 2)
348	{
349	pHeader->Version.v2.u64BackingFileOffset = RT_BE2H_U64(pHeader->Version.v2.u64BackingFileOffset);
350	pHeader->Version.v2.u32BackingFileSize = RT_BE2H_U32(pHeader->Version.v2.u32BackingFileSize);
351	pHeader->Version.v2.u32ClusterBits = RT_BE2H_U32(pHeader->Version.v2.u32ClusterBits);
352	pHeader->Version.v2.u64Size = RT_BE2H_U64(pHeader->Version.v2.u64Size);
353	pHeader->Version.v2.u32CryptMethod = RT_BE2H_U32(pHeader->Version.v2.u32CryptMethod);
354	pHeader->Version.v2.u32L1Size = RT_BE2H_U32(pHeader->Version.v2.u32L1Size);
355	pHeader->Version.v2.u64L1TableOffset = RT_BE2H_U64(pHeader->Version.v2.u64L1TableOffset);
356	pHeader->Version.v2.u64RefcountTableOffset = RT_BE2H_U64(pHeader->Version.v2.u64RefcountTableOffset);
357	pHeader->Version.v2.u32RefcountTableClusters = RT_BE2H_U32(pHeader->Version.v2.u32RefcountTableClusters);
358	pHeader->Version.v2.u32NbSnapshots = RT_BE2H_U32(pHeader->Version.v2.u32NbSnapshots);
359	pHeader->Version.v2.u64SnapshotsOffset = RT_BE2H_U64(pHeader->Version.v2.u64SnapshotsOffset);
360	}
361	else
362	return false;
363
364	return true;
365	}
366
367	/**
368	* Creates a QCOW header from the given image state.
369	*
370	* @returns nothing.
371	* @param pImage Image instance data.
372	* @param pHeader Pointer to the header to convert.
373	* @param pcbHeader Where to store the size of the header to write.
374	*/
375	static void qcowHdrConvertFromHostEndianess(PQCOWIMAGE pImage, PQCowHeader pHeader,
376	size_t *pcbHeader)
377	{
378	memset(pHeader, 0, sizeof(QCowHeader));
379
380	pHeader->u32Magic = RT_H2BE_U32(QCOW_MAGIC);
381	pHeader->u32Version = RT_H2BE_U32(pImage->uVersion);
382	if (pImage->uVersion == 1)
383	{
384	pHeader->Version.v1.u64BackingFileOffset = RT_H2BE_U64(pImage->offBackingFilename);
385	pHeader->Version.v1.u32BackingFileSize = RT_H2BE_U32(pImage->cbBackingFilename);
386	pHeader->Version.v1.u32MTime = RT_H2BE_U32(pImage->MTime);
387	pHeader->Version.v1.u64Size = RT_H2BE_U64(pImage->cbSize);
388	pHeader->Version.v1.u8ClusterBits = (uint8_t)qcowGetPowerOfTwo(pImage->cbCluster);
389	pHeader->Version.v1.u8L2Bits = (uint8_t)qcowGetPowerOfTwo(pImage->cL2TableEntries);
390	pHeader->Version.v1.u32CryptMethod = RT_H2BE_U32(0);
391	pHeader->Version.v1.u64L1TableOffset = RT_H2BE_U64(pImage->offL1Table);
392	*pcbHeader = QCOW_V1_HDR_SIZE;
393	}
394	else if (pImage->uVersion == 2)
395	{
396	pHeader->Version.v2.u64BackingFileOffset = RT_H2BE_U64(pImage->offBackingFilename);
397	pHeader->Version.v2.u32BackingFileSize = RT_H2BE_U32(pImage->cbBackingFilename);
398	pHeader->Version.v2.u32ClusterBits = RT_H2BE_U32(qcowGetPowerOfTwo(pImage->cbCluster));
399	pHeader->Version.v2.u64Size = RT_H2BE_U64(pImage->cbSize);
400	pHeader->Version.v2.u32CryptMethod = RT_H2BE_U32(0);
401	pHeader->Version.v2.u32L1Size = RT_H2BE_U32(pImage->cL1TableEntries);
402	pHeader->Version.v2.u64L1TableOffset = RT_H2BE_U64(pImage->offL1Table);
403	pHeader->Version.v2.u64RefcountTableOffset = RT_H2BE_U64(pImage->offRefcountTable);
404	pHeader->Version.v2.u32RefcountTableClusters = RT_H2BE_U32(pImage->cbRefcountTable / pImage->cbCluster);
405	pHeader->Version.v2.u32NbSnapshots = RT_H2BE_U32(0);
406	pHeader->Version.v2.u64SnapshotsOffset = RT_H2BE_U64((uint64_t)0);
407	*pcbHeader = QCOW_V2_HDR_SIZE;
408	}
409	else
410	AssertMsgFailed(("Invalid version of the QCOW image format %d\n", pImage->uVersion));
411	}
412
413	/**
414	* Convert table entries from little endian to host endianess.
415	*
416	* @returns nothing.
417	* @param paTbl Pointer to the table.
418	* @param cEntries Number of entries in the table.
419	*/
420	static void qcowTableConvertToHostEndianess(uint64_t *paTbl, uint32_t cEntries)
421	{
422	while(cEntries-- > 0)
423	{
424	paTbl = RT_BE2H_U64(paTbl);
425	paTbl++;
426	}
427	}
428
429	/**
430	* Convert table entries from host to little endian format.
431	*
432	* @returns nothing.
433	* @param paTblImg Pointer to the table which will store the little endian table.
434	* @param paTbl The source table to convert.
435	* @param cEntries Number of entries in the table.
436	*/
437	static void qcowTableConvertFromHostEndianess(uint64_t paTblImg, uint64_t paTbl,
438	uint32_t cEntries)
439	{
440	while(cEntries-- > 0)
441	{
442	paTblImg = RT_H2BE_U64(paTbl);
443	paTbl++;
444	paTblImg++;
445	}
446	}
447
448	/**
449	* Convert refcount table entries from little endian to host endianess.
450	*
451	* @returns nothing.
452	* @param paTbl Pointer to the table.
453	* @param cEntries Number of entries in the table.
454	*/
455	static void qcowRefcountTableConvertToHostEndianess(uint16_t *paTbl, uint32_t cEntries)
456	{
457	while(cEntries-- > 0)
458	{
459	paTbl = RT_BE2H_U16(paTbl);
460	paTbl++;
461	}
462	}
463
464	/**
465	* Convert table entries from host to little endian format.
466	*
467	* @returns nothing.
468	* @param paTblImg Pointer to the table which will store the little endian table.
469	* @param paTbl The source table to convert.
470	* @param cEntries Number of entries in the table.
471	*/
472	static void qcowRefcountTableConvertFromHostEndianess(uint16_t paTblImg, uint16_t paTbl,
473	uint32_t cEntries)
474	{
475	while(cEntries-- > 0)
476	{
477	paTblImg = RT_H2BE_U16(paTbl);
478	paTbl++;
479	paTblImg++;
480	}
481	}
482
483	/**
484	* Creates the L2 table cache.
485	*
486	* @returns VBox status code.
487	* @param pImage The image instance data.
488	*/
489	static int qcowL2TblCacheCreate(PQCOWIMAGE pImage)
490	{
491	pImage->cbL2Cache = 0;
492	RTListInit(&pImage->ListSearch);
493	RTListInit(&pImage->ListLru);
494
495	return VINF_SUCCESS;
496	}
497
498	/**
499	* Destroys the L2 table cache.
500	*
501	* @returns nothing.
502	* @param pImage The image instance data.
503	*/
504	static void qcowL2TblCacheDestroy(PQCOWIMAGE pImage)
505	{
506	PQCOWL2CACHEENTRY pL2Entry = NULL;
507	PQCOWL2CACHEENTRY pL2Next = NULL;
508
509	RTListForEachSafe(&pImage->ListSearch, pL2Entry, pL2Next, QCOWL2CACHEENTRY, NodeSearch)
510	{
511	Assert(!pL2Entry->cRefs);
512
513	RTListNodeRemove(&pL2Entry->NodeSearch);
514	RTMemPageFree(pL2Entry->paL2Tbl, pImage->cbL2Table);
515	RTMemFree(pL2Entry);
516	}
517
518	pImage->cbL2Cache = 0;
519	RTListInit(&pImage->ListSearch);
520	RTListInit(&pImage->ListLru);
521	}
522
523	/**
524	* Returns the L2 table matching the given offset or NULL if none could be found.
525	*
526	* @returns Pointer to the L2 table cache entry or NULL.
527	* @param pImage The image instance data.
528	* @param offL2Tbl Offset of the L2 table to search for.
529	*/
530	static PQCOWL2CACHEENTRY qcowL2TblCacheRetain(PQCOWIMAGE pImage, uint64_t offL2Tbl)
531	{
532	PQCOWL2CACHEENTRY pL2Entry = NULL;
533
534	RTListForEach(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch)
535	{
536	if (pL2Entry->offL2Tbl == offL2Tbl)
537	break;
538	}
539
540	if (!RTListNodeIsDummy(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch))
541	{
542	/* Update LRU list. */
543	RTListNodeRemove(&pL2Entry->NodeLru);
544	RTListPrepend(&pImage->ListLru, &pL2Entry->NodeLru);
545	pL2Entry->cRefs++;
546	return pL2Entry;
547	}
548	else
549	return NULL;
550	}
551
552	/**
553	* Releases a L2 table cache entry.
554	*
555	* @returns nothing.
556	* @param pL2Entry The L2 cache entry.
557	*/
558	static void qcowL2TblCacheEntryRelease(PQCOWL2CACHEENTRY pL2Entry)
559	{
560	Assert(pL2Entry->cRefs > 0);
561	pL2Entry->cRefs--;
562	}
563
564	/**
565	* Allocates a new L2 table from the cache evicting old entries if required.
566	*
567	* @returns Pointer to the L2 cache entry or NULL.
568	* @param pImage The image instance data.
569	*/
570	static PQCOWL2CACHEENTRY qcowL2TblCacheEntryAlloc(PQCOWIMAGE pImage)
571	{
572	PQCOWL2CACHEENTRY pL2Entry = NULL;
573	int rc = VINF_SUCCESS;
574
575	if (pImage->cbL2Cache + pImage->cbL2Table <= QCOW_L2_CACHE_MEMORY_MAX)
576	{
577	/* Add a new entry. */
578	pL2Entry = (PQCOWL2CACHEENTRY)RTMemAllocZ(sizeof(QCOWL2CACHEENTRY));
579	if (pL2Entry)
580	{
581	pL2Entry->paL2Tbl = (uint64_t *)RTMemPageAllocZ(pImage->cbL2Table);
582	if (RT_UNLIKELY(!pL2Entry->paL2Tbl))
583	{
584	RTMemFree(pL2Entry);
585	pL2Entry = NULL;
586	}
587	else
588	{
589	pL2Entry->cRefs = 1;
590	pImage->cbL2Cache += pImage->cbL2Table;
591	}
592	}
593	}
594	else
595	{
596	/* Evict the last not in use entry and use it */
597	Assert(!RTListIsEmpty(&pImage->ListLru));
598
599	RTListForEachReverse(&pImage->ListLru, pL2Entry, QCOWL2CACHEENTRY, NodeLru)
600	{
601	if (!pL2Entry->cRefs)
602	break;
603	}
604
605	if (!RTListNodeIsDummy(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch))
606	{
607	RTListNodeRemove(&pL2Entry->NodeSearch);
608	RTListNodeRemove(&pL2Entry->NodeLru);
609	pL2Entry->offL2Tbl = 0;
610	pL2Entry->cRefs = 1;
611	}
612	else
613	pL2Entry = NULL;
614	}
615
616	return pL2Entry;
617	}
618
619	/**
620	* Frees a L2 table cache entry.
621	*
622	* @returns nothing.
623	* @param pImage The image instance data.
624	* @param pL2Entry The L2 cache entry to free.
625	*/
626	static void qcowL2TblCacheEntryFree(PQCOWIMAGE pImage, PQCOWL2CACHEENTRY pL2Entry)
627	{
628	Assert(!pL2Entry->cRefs);
629	RTMemPageFree(pL2Entry->paL2Tbl, pImage->cbL2Table);
630	RTMemFree(pL2Entry);
631
632	pImage->cbL2Cache -= pImage->cbL2Table;
633	}
634
635	/**
636	* Inserts an entry in the L2 table cache.
637	*
638	* @returns nothing.
639	* @param pImage The image instance data.
640	* @param pL2Entry The L2 cache entry to insert.
641	*/
642	static void qcowL2TblCacheEntryInsert(PQCOWIMAGE pImage, PQCOWL2CACHEENTRY pL2Entry)
643	{
644	PQCOWL2CACHEENTRY pIt = NULL;
645
646	Assert(pL2Entry->offL2Tbl > 0);
647
648	/* Insert at the top of the LRU list. */
649	RTListPrepend(&pImage->ListLru, &pL2Entry->NodeLru);
650
651	if (RTListIsEmpty(&pImage->ListSearch))
652	{
653	RTListAppend(&pImage->ListSearch, &pL2Entry->NodeSearch);
654	}
655	else
656	{
657	/* Insert into search list. */
658	pIt = RTListGetFirst(&pImage->ListSearch, QCOWL2CACHEENTRY, NodeSearch);
659	if (pIt->offL2Tbl > pL2Entry->offL2Tbl)
660	RTListPrepend(&pImage->ListSearch, &pL2Entry->NodeSearch);
661	else
662	{
663	bool fInserted = false;
664
665	RTListForEach(&pImage->ListSearch, pIt, QCOWL2CACHEENTRY, NodeSearch)
666	{
667	Assert(pIt->offL2Tbl != pL2Entry->offL2Tbl);
668	if (pIt->offL2Tbl < pL2Entry->offL2Tbl)
669	{
670	RTListNodeInsertAfter(&pIt->NodeSearch, &pL2Entry->NodeSearch);
671	fInserted = true;
672	break;
673	}
674	}
675	Assert(fInserted);
676	}
677	}
678	}
679
680	/**
681	* Fetches the L2 from the given offset trying the LRU cache first and
682	* reading it from the image after a cache miss.
683	*
684	* @returns VBox status code.
685	* @param pImage Image instance data.
686	* @param offL2Tbl The offset of the L2 table in the image.
687	* @param ppL2Entry Where to store the L2 table on success.
688	*/
689	static int qcowL2TblCacheFetch(PQCOWIMAGE pImage, uint64_t offL2Tbl, PQCOWL2CACHEENTRY *ppL2Entry)
690	{
691	int rc = VINF_SUCCESS;
692
693	LogFlowFunc(("pImage=%#p offL2Tbl=%llu ppL2Entry=%#p\n", pImage, offL2Tbl, ppL2Entry));
694
695	/* Try to fetch the L2 table from the cache first. */
696	PQCOWL2CACHEENTRY pL2Entry = qcowL2TblCacheRetain(pImage, offL2Tbl);
697	if (!pL2Entry)
698	{
699	LogFlowFunc(("Reading L2 table from image\n"));
700	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
701
702	if (pL2Entry)
703	{
704	/* Read from the image. */
705	pL2Entry->offL2Tbl = offL2Tbl;
706	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage, offL2Tbl,
707	pL2Entry->paL2Tbl, pImage->cbL2Table, NULL);
708	if (RT_SUCCESS(rc))
709	{
710	#if defined(RT_LITTLE_ENDIAN)
711	qcowTableConvertToHostEndianess(pL2Entry->paL2Tbl, pImage->cL2TableEntries);
712	#endif
713	qcowL2TblCacheEntryInsert(pImage, pL2Entry);
714	}
715	else
716	{
717	qcowL2TblCacheEntryRelease(pL2Entry);
718	qcowL2TblCacheEntryFree(pImage, pL2Entry);
719	}
720	}
721	else
722	rc = VERR_NO_MEMORY;
723	}
724
725	if (RT_SUCCESS(rc))
726	*ppL2Entry = pL2Entry;
727
728	LogFlowFunc(("returns rc=%Rrc\n", rc));
729	return rc;
730	}
731
732	/**
733	* Fetches the L2 from the given offset trying the LRU cache first and
734	* reading it from the image after a cache miss - version for async I/O.
735	*
736	* @returns VBox status code.
737	* @param pImage Image instance data.
738	* @param pIoCtx The I/O context.
739	* @param offL2Tbl The offset of the L2 table in the image.
740	* @param ppL2Entry Where to store the L2 table on success.
741	*/
742	static int qcowL2TblCacheFetchAsync(PQCOWIMAGE pImage, PVDIOCTX pIoCtx,
743	uint64_t offL2Tbl, PQCOWL2CACHEENTRY *ppL2Entry)
744	{
745	int rc = VINF_SUCCESS;
746
747	/* Try to fetch the L2 table from the cache first. */
748	PQCOWL2CACHEENTRY pL2Entry = qcowL2TblCacheRetain(pImage, offL2Tbl);
749	if (!pL2Entry)
750	{
751	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
752
753	if (pL2Entry)
754	{
755	/* Read from the image. */
756	PVDMETAXFER pMetaXfer;
757
758	pL2Entry->offL2Tbl = offL2Tbl;
759	rc = vdIfIoIntFileReadMetaAsync(pImage->pIfIo, pImage->pStorage,
760	offL2Tbl, pL2Entry->paL2Tbl,
761	pImage->cbL2Table, pIoCtx,
762	&pMetaXfer, NULL, NULL);
763	if (RT_SUCCESS(rc))
764	{
765	vdIfIoIntMetaXferRelease(pImage->pIfIo, pMetaXfer);
766	#if defined(RT_LITTLE_ENDIAN)
767	qcowTableConvertToHostEndianess(pL2Entry->paL2Tbl, pImage->cL2TableEntries);
768	#endif
769	qcowL2TblCacheEntryInsert(pImage, pL2Entry);
770	}
771	else
772	{
773	qcowL2TblCacheEntryRelease(pL2Entry);
774	qcowL2TblCacheEntryFree(pImage, pL2Entry);
775	}
776	}
777	else
778	rc = VERR_NO_MEMORY;
779	}
780
781	if (RT_SUCCESS(rc))
782	*ppL2Entry = pL2Entry;
783
784	return rc;
785	}
786
787	/**
788	* Sets the L1, L2 and offset bitmasks and L1 and L2 bit shift members.
789	*
790	* @returns nothing.
791	* @param pImage The image instance data.
792	*/
793	static void qcowTableMasksInit(PQCOWIMAGE pImage)
794	{
795	uint32_t cClusterBits, cL2TableBits;
796
797	cClusterBits = qcowGetPowerOfTwo(pImage->cbCluster);
798	cL2TableBits = qcowGetPowerOfTwo(pImage->cL2TableEntries);
799
800	Assert(cClusterBits + cL2TableBits < 64);
801
802	pImage->fOffsetMask = ((uint64_t)pImage->cbCluster - 1);
803	pImage->fL2Mask = ((uint64_t)pImage->cL2TableEntries - 1) << cClusterBits;
804	pImage->cL2Shift = cClusterBits;
805	pImage->cL1Shift = cClusterBits + cL2TableBits;
806	}
807
808	/**
809	* Converts a given logical offset into the
810	*
811	* @returns nothing.
812	* @param pImage The image instance data.
813	* @param off The logical offset to convert.
814	* @param pidxL1 Where to store the index in the L1 table on success.
815	* @param pidxL2 Where to store the index in the L2 table on success.
816	* @param poffCluster Where to store the offset in the cluster on success.
817	*/
818	DECLINLINE(void) qcowConvertLogicalOffset(PQCOWIMAGE pImage, uint64_t off, uint32_t *pidxL1,
819	uint32_t pidxL2, uint32_t poffCluster)
820	{
821	AssertPtr(pidxL1);
822	AssertPtr(pidxL2);
823	AssertPtr(poffCluster);
824
825	*poffCluster = off & pImage->fOffsetMask;
826	*pidxL1 = off >> pImage->cL1Shift;
827	*pidxL2 = (off & pImage->fL2Mask) >> pImage->cL2Shift;
828	}
829
830	/**
831	* Converts Cluster size to a byte size.
832	*
833	* @returns Number of bytes derived from the given number of clusters.
834	* @param pImage The image instance data.
835	* @param cClusters The clusters to convert.
836	*/
837	DECLINLINE(uint64_t) qcowCluster2Byte(PQCOWIMAGE pImage, uint64_t cClusters)
838	{
839	return cClusters * pImage->cbCluster;
840	}
841
842	/**
843	* Converts number of bytes to cluster size rounding to the next cluster.
844	*
845	* @returns Number of bytes derived from the given number of clusters.
846	* @param pImage The image instance data.
847	* @param cb Number of bytes to convert.
848	*/
849	DECLINLINE(uint64_t) qcowByte2Cluster(PQCOWIMAGE pImage, uint64_t cb)
850	{
851	return cb / pImage->cbCluster + (cb % pImage->cbCluster ? 1 : 0);
852	}
853
854	/**
855	* Allocates a new cluster in the image.
856	*
857	* @returns The start offset of the new cluster in the image.
858	* @param pImage The image instance data.
859	* @param cCLusters Number of clusters to allocate.
860	*/
861	DECLINLINE(uint64_t) qcowClusterAllocate(PQCOWIMAGE pImage, uint32_t cClusters)
862	{
863	uint64_t offCluster;
864
865	offCluster = pImage->offNextCluster;
866	pImage->offNextCluster += cClusters*pImage->cbCluster;
867
868	return offCluster;
869	}
870
871	/**
872	* Returns the real image offset for a given cluster or an error if the cluster is not
873	* yet allocated.
874	*
875	* @returns VBox status code.
876	* VERR_VD_BLOCK_FREE if the cluster is not yet allocated.
877	* @param pImage The image instance data.
878	* @param idxL1 The L1 index.
879	* @param idxL2 The L2 index.
880	* @param offCluster Offset inside the cluster.
881	* @param poffImage Where to store the image offset on success;
882	*/
883	static int qcowConvertToImageOffset(PQCOWIMAGE pImage, uint32_t idxL1, uint32_t idxL2,
884	uint32_t offCluster, uint64_t *poffImage)
885	{
886	int rc = VERR_VD_BLOCK_FREE;
887	LogFlowFunc(("pImage=%#p idxL1=%u idxL2=%u offCluster=%u poffImage=%#p\n",
888	pImage, idxL1, idxL2, offCluster, poffImage));
889
890	AssertReturn(idxL1 < pImage->cL1TableEntries, VERR_INVALID_PARAMETER);
891	AssertReturn(idxL2 < pImage->cL2TableEntries, VERR_INVALID_PARAMETER);
892
893	if (pImage->paL1Table[idxL1])
894	{
895	PQCOWL2CACHEENTRY pL2Entry;
896
897	rc = qcowL2TblCacheFetch(pImage, pImage->paL1Table[idxL1], &pL2Entry);
898	if (RT_SUCCESS(rc))
899	{
900	LogFlowFunc(("cluster start offset %llu\n", pL2Entry->paL2Tbl[idxL2]));
901	/* Get real file offset. */
902	if (pL2Entry->paL2Tbl[idxL2])
903	{
904	uint64_t off = pL2Entry->paL2Tbl[idxL2];
905
906	/* Strip flags */
907	if (pImage->uVersion == 2)
908	{
909	if (RT_UNLIKELY(off & QCOW_V2_COMPRESSED_FLAG))
910	rc = VERR_NOT_SUPPORTED;
911	else
912	off &= ~(QCOW_V2_COMPRESSED_FLAG \| QCOW_V2_COPIED_FLAG);
913	}
914	else
915	{
916	if (RT_UNLIKELY(off & QCOW_V1_COMPRESSED_FLAG))
917	rc = VERR_NOT_SUPPORTED;
918	else
919	off &= ~QCOW_V1_COMPRESSED_FLAG;
920	}
921
922	*poffImage = off + offCluster;
923	}
924	else
925	rc = VERR_VD_BLOCK_FREE;
926
927	qcowL2TblCacheEntryRelease(pL2Entry);
928	}
929	}
930
931	LogFlowFunc(("returns rc=%Rrc\n", rc));
932	return rc;
933	}
934
935	/**
936	* Returns the real image offset for a given cluster or an error if the cluster is not
937	* yet allocated- version for async I/O.
938	*
939	* @returns VBox status code.
940	* VERR_VD_BLOCK_FREE if the cluster is not yet allocated.
941	* @param pImage The image instance data.
942	* @param pIoCtx The I/O context.
943	* @param idxL1 The L1 index.
944	* @param idxL2 The L2 index.
945	* @param offCluster Offset inside the cluster.
946	* @param poffImage Where to store the image offset on success;
947	*/
948	static int qcowConvertToImageOffsetAsync(PQCOWIMAGE pImage, PVDIOCTX pIoCtx,
949	uint32_t idxL1, uint32_t idxL2,
950	uint32_t offCluster, uint64_t *poffImage)
951	{
952	int rc = VERR_VD_BLOCK_FREE;
953
954	AssertReturn(idxL1 < pImage->cL1TableEntries, VERR_INVALID_PARAMETER);
955	AssertReturn(idxL2 < pImage->cL2TableEntries, VERR_INVALID_PARAMETER);
956
957	if (pImage->paL1Table[idxL1])
958	{
959	PQCOWL2CACHEENTRY pL2Entry;
960
961	rc = qcowL2TblCacheFetchAsync(pImage, pIoCtx, pImage->paL1Table[idxL1],
962	&pL2Entry);
963	if (RT_SUCCESS(rc))
964	{
965	/* Get real file offset. */
966	if (pL2Entry->paL2Tbl[idxL2])
967	{
968	uint64_t off = pL2Entry->paL2Tbl[idxL2];
969
970	/* Strip flags */
971	if (pImage->uVersion == 2)
972	{
973	if (RT_UNLIKELY(off & QCOW_V2_COMPRESSED_FLAG))
974	rc = VERR_NOT_SUPPORTED;
975	else
976	off &= ~(QCOW_V2_COMPRESSED_FLAG \| QCOW_V2_COPIED_FLAG);
977	}
978	else
979	{
980	if (RT_UNLIKELY(off & QCOW_V1_COMPRESSED_FLAG))
981	rc = VERR_NOT_SUPPORTED;
982	else
983	off &= ~QCOW_V1_COMPRESSED_FLAG;
984	}
985
986	*poffImage = off + offCluster;
987	}
988	else
989	rc = VERR_VD_BLOCK_FREE;
990
991	qcowL2TblCacheEntryRelease(pL2Entry);
992	}
993	}
994
995	return rc;
996	}
997
998
999	/**
1000	* Internal. Flush image data to disk.
1001	*/
1002	static int qcowFlushImage(PQCOWIMAGE pImage)
1003	{
1004	int rc = VINF_SUCCESS;
1005
1006	if ( pImage->pStorage
1007	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
1008	&& pImage->cbL1Table)
1009	{
1010	QCowHeader Header;
1011
1012	#if defined(RT_LITTLE_ENDIAN)
1013	uint64_t paL1TblImg = (uint64_t )RTMemAllocZ(pImage->cbL1Table);
1014	if (paL1TblImg)
1015	{
1016	qcowTableConvertFromHostEndianess(paL1TblImg, pImage->paL1Table,
1017	pImage->cL1TableEntries);
1018	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
1019	pImage->offL1Table, paL1TblImg,
1020	pImage->cbL1Table, NULL);
1021	RTMemFree(paL1TblImg);
1022	}
1023	else
1024	rc = VERR_NO_MEMORY;
1025	#else
1026	/* Write L1 table directly. */
1027	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, pImage->offL1Table,
1028	pImage->paL1Table, pImage->cbL1Table, NULL);
1029	#endif
1030	if (RT_SUCCESS(rc))
1031	{
1032	/* Write header. */
1033	size_t cbHeader = 0;
1034	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
1035	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, 0, &Header,
1036	cbHeader, NULL);
1037	if (RT_SUCCESS(rc))
1038	rc = vdIfIoIntFileFlushSync(pImage->pIfIo, pImage->pStorage);
1039	}
1040	}
1041
1042	return rc;
1043	}
1044
1045	/**
1046	* Flush image data to disk - version for async I/O.
1047	*
1048	* @returns VBox status code.
1049	* @param pImage The image instance data.
1050	* @param pIoCtx The I/o context
1051	*/
1052	static int qcowFlushImageAsync(PQCOWIMAGE pImage, PVDIOCTX pIoCtx)
1053	{
1054	int rc = VINF_SUCCESS;
1055
1056	if ( pImage->pStorage
1057	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
1058	{
1059	QCowHeader Header;
1060
1061	#if defined(RT_LITTLE_ENDIAN)
1062	uint64_t paL1TblImg = (uint64_t )RTMemAllocZ(pImage->cbL1Table);
1063	if (paL1TblImg)
1064	{
1065	qcowTableConvertFromHostEndianess(paL1TblImg, pImage->paL1Table,
1066	pImage->cL1TableEntries);
1067	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
1068	pImage->offL1Table, paL1TblImg,
1069	pImage->cbL1Table, pIoCtx, NULL, NULL);
1070	RTMemFree(paL1TblImg);
1071	}
1072	else
1073	rc = VERR_NO_MEMORY;
1074	#else
1075	/* Write L1 table directly. */
1076	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
1077	pImage->offL1Table, pImage->paL1Table,
1078	pImage->cbL1Table, pIoCtx, NULL, NULL);
1079	#endif
1080	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1081	{
1082	/* Write header. */
1083	size_t cbHeader = 0;
1084	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
1085	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
1086	0, &Header, cbHeader,
1087	pIoCtx, NULL, NULL);
1088	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1089	rc = vdIfIoIntFileFlushAsync(pImage->pIfIo, pImage->pStorage,
1090	pIoCtx, NULL, NULL);
1091	}
1092	}
1093
1094	return rc;
1095	}
1096
1097	/**
1098	* Internal. Free all allocated space for representing an image except pImage,
1099	* and optionally delete the image from disk.
1100	*/
1101	static int qcowFreeImage(PQCOWIMAGE pImage, bool fDelete)
1102	{
1103	int rc = VINF_SUCCESS;
1104
1105	/* Freeing a never allocated image (e.g. because the open failed) is
1106	* not signalled as an error. After all nothing bad happens. */
1107	if (pImage)
1108	{
1109	if (pImage->pStorage)
1110	{
1111	/* No point updating the file that is deleted anyway. */
1112	if (!fDelete)
1113	qcowFlushImage(pImage);
1114
1115	vdIfIoIntFileClose(pImage->pIfIo, pImage->pStorage);
1116	pImage->pStorage = NULL;
1117	}
1118
1119	if (pImage->paL1Table)
1120	RTMemFree(pImage->paL1Table);
1121
1122	if (pImage->pszBackingFilename)
1123	RTMemFree(pImage->pszBackingFilename);
1124
1125	qcowL2TblCacheDestroy(pImage);
1126
1127	if (fDelete && pImage->pszFilename)
1128	vdIfIoIntFileDelete(pImage->pIfIo, pImage->pszFilename);
1129	}
1130
1131	LogFlowFunc(("returns %Rrc\n", rc));
1132	return rc;
1133	}
1134
1135	/**
1136	* Internal: Open an image, constructing all necessary data structures.
1137	*/
1138	static int qcowOpenImage(PQCOWIMAGE pImage, unsigned uOpenFlags)
1139	{
1140	int rc;
1141
1142	pImage->uOpenFlags = uOpenFlags;
1143
1144	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1145	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1146	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1147
1148	/*
1149	* Open the image.
1150	*/
1151	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename,
1152	VDOpenFlagsToFileOpenFlags(uOpenFlags,
1153	false /* fCreate */),
1154	&pImage->pStorage);
1155	if (RT_FAILURE(rc))
1156	{
1157	/* Do NOT signal an appropriate error here, as the VD layer has the
1158	* choice of retrying the open if it failed. */
1159	goto out;
1160	}
1161
1162	uint64_t cbFile;
1163	QCowHeader Header;
1164	rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
1165	if (RT_FAILURE(rc))
1166	goto out;
1167	if (cbFile > sizeof(Header))
1168	{
1169	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage, 0, &Header, sizeof(Header), NULL);
1170	if ( RT_SUCCESS(rc)
1171	&& qcowHdrConvertToHostEndianess(&Header))
1172	{
1173	pImage->offNextCluster = RT_ALIGN_64(cbFile, 512); /* Align image to sector boundary. */
1174	Assert(pImage->offNextCluster >= cbFile);
1175
1176	rc = qcowL2TblCacheCreate(pImage);
1177	AssertRC(rc);
1178
1179	if (Header.u32Version == 1)
1180	{
1181	if (!Header.Version.v1.u32CryptMethod)
1182	{
1183	pImage->uVersion = 1;
1184	pImage->offBackingFilename = Header.Version.v1.u64BackingFileOffset;
1185	pImage->cbBackingFilename = Header.Version.v1.u32BackingFileSize;
1186	pImage->MTime = Header.Version.v1.u32MTime;
1187	pImage->cbSize = Header.Version.v1.u64Size;
1188	pImage->cbCluster = RT_BIT_32(Header.Version.v1.u8ClusterBits);
1189	pImage->cL2TableEntries = RT_BIT_32(Header.Version.v1.u8L2Bits);
1190	pImage->cbL2Table = RT_ALIGN_64(pImage->cL2TableEntries * sizeof(uint64_t), pImage->cbCluster);
1191	pImage->offL1Table = Header.Version.v1.u64L1TableOffset;
1192	pImage->cL1TableEntries = pImage->cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1193	if (pImage->cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1194	pImage->cL1TableEntries++;
1195	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1196	}
1197	else
1198	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1199	N_("QCow: Encrypted image '%s' is not supported"),
1200	pImage->pszFilename);
1201	}
1202	else if (Header.u32Version == 2)
1203	{
1204	if (Header.Version.v2.u32CryptMethod)
1205	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1206	N_("QCow: Encrypted image '%s' is not supported"),
1207	pImage->pszFilename);
1208	else if (Header.Version.v2.u32NbSnapshots)
1209	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1210	N_("QCow: Image '%s' contains snapshots which is not supported"),
1211	pImage->pszFilename);
1212	else
1213	{
1214	pImage->uVersion = 2;
1215	pImage->offBackingFilename = Header.Version.v2.u64BackingFileOffset;
1216	pImage->cbBackingFilename = Header.Version.v2.u32BackingFileSize;
1217	pImage->cbSize = Header.Version.v2.u64Size;
1218	pImage->cbCluster = RT_BIT_32(Header.Version.v2.u32ClusterBits);
1219	pImage->cL2TableEntries = pImage->cbCluster / sizeof(uint64_t);
1220	pImage->cbL2Table = pImage->cbCluster;
1221	pImage->offL1Table = Header.Version.v2.u64L1TableOffset;
1222	pImage->cL1TableEntries = Header.Version.v2.u32L1Size;
1223	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1224	pImage->offRefcountTable = Header.Version.v2.u64RefcountTableOffset;
1225	pImage->cbRefcountTable = qcowCluster2Byte(pImage, Header.Version.v2.u32RefcountTableClusters);
1226	pImage->cRefcountTableEntries = pImage->cbRefcountTable / sizeof(uint64_t);
1227	}
1228	}
1229	else
1230	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1231	N_("QCow: Image '%s' uses version %u which is not supported"),
1232	pImage->pszFilename, Header.u32Version);
1233
1234	/** @todo: Check that there are no compressed clusters in the image
1235	* (by traversing the L2 tables and checking each offset).
1236	* Refuse to open such images.
1237	*/
1238
1239	if ( RT_SUCCESS(rc)
1240	&& pImage->cbBackingFilename
1241	&& pImage->offBackingFilename)
1242	{
1243	/* Load backing filename from image. */
1244	pImage->pszFilename = (char )RTMemAllocZ(pImage->cbBackingFilename + 1); / +1 for \0 terminator. */
1245	if (pImage->pszFilename)
1246	{
1247	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1248	pImage->offBackingFilename, pImage->pszBackingFilename,
1249	pImage->cbBackingFilename, NULL);
1250	}
1251	else
1252	rc = VERR_NO_MEMORY;
1253	}
1254
1255	if ( RT_SUCCESS(rc)
1256	&& pImage->cbRefcountTable
1257	&& pImage->offRefcountTable)
1258	{
1259	/* Load refcount table. */
1260	Assert(pImage->cRefcountTableEntries);
1261	pImage->paRefcountTable = (uint64_t *)RTMemAllocZ(pImage->cbRefcountTable);
1262	if (RT_LIKELY(pImage->paRefcountTable))
1263	{
1264	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1265	pImage->offRefcountTable, pImage->paRefcountTable,
1266	pImage->cbRefcountTable, NULL);
1267	if (RT_SUCCESS(rc))
1268	qcowTableConvertToHostEndianess(pImage->paRefcountTable,
1269	pImage->cRefcountTableEntries);
1270	else
1271	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1272	N_("QCow: Reading refcount table of image '%s' failed"),
1273	pImage->pszFilename);
1274	}
1275	else
1276	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1277	N_("QCow: Allocating memory for refcount table of image '%s' failed"),
1278	pImage->pszFilename);
1279	}
1280
1281	if (RT_SUCCESS(rc))
1282	{
1283	qcowTableMasksInit(pImage);
1284
1285	/* Allocate L1 table. */
1286	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1287	if (pImage->paL1Table)
1288	{
1289	/* Read from the image. */
1290	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1291	pImage->offL1Table, pImage->paL1Table,
1292	pImage->cbL1Table, NULL);
1293	if (RT_SUCCESS(rc))
1294	qcowTableConvertToHostEndianess(pImage->paL1Table, pImage->cL1TableEntries);
1295	else
1296	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1297	N_("QCow: Reading the L1 table for image '%s' failed"),
1298	pImage->pszFilename);
1299	}
1300	else
1301	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1302	N_("QCow: Out of memory allocating L1 table for image '%s'"),
1303	pImage->pszFilename);
1304	}
1305	}
1306	else if (RT_SUCCESS(rc))
1307	rc = VERR_VD_GEN_INVALID_HEADER;
1308	}
1309	else
1310	rc = VERR_VD_GEN_INVALID_HEADER;
1311
1312	out:
1313	if (RT_FAILURE(rc))
1314	qcowFreeImage(pImage, false);
1315	return rc;
1316	}
1317
1318	/**
1319	* Internal: Create a qcow image.
1320	*/
1321	static int qcowCreateImage(PQCOWIMAGE pImage, uint64_t cbSize,
1322	unsigned uImageFlags, const char *pszComment,
1323	PCVDGEOMETRY pPCHSGeometry,
1324	PCVDGEOMETRY pLCHSGeometry, unsigned uOpenFlags,
1325	PFNVDPROGRESS pfnProgress, void *pvUser,
1326	unsigned uPercentStart, unsigned uPercentSpan)
1327	{
1328	int rc;
1329	int32_t fOpen;
1330
1331	if (uImageFlags & VD_IMAGE_FLAGS_FIXED)
1332	{
1333	rc = vdIfError(pImage->pIfError, VERR_VD_INVALID_TYPE, RT_SRC_POS, N_("QCow: cannot create fixed image '%s'"), pImage->pszFilename);
1334	goto out;
1335	}
1336
1337	pImage->uOpenFlags = uOpenFlags & ~VD_OPEN_FLAGS_READONLY;
1338	pImage->uImageFlags = uImageFlags;
1339	pImage->PCHSGeometry = *pPCHSGeometry;
1340	pImage->LCHSGeometry = *pLCHSGeometry;
1341
1342	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1343	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1344	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1345
1346	/* Create image file. */
1347	fOpen = VDOpenFlagsToFileOpenFlags(pImage->uOpenFlags, true /* fCreate */);
1348	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename, fOpen, &pImage->pStorage);
1349	if (RT_FAILURE(rc))
1350	{
1351	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: cannot create image '%s'"), pImage->pszFilename);
1352	goto out;
1353	}
1354
1355	/* Init image state. */
1356	pImage->uVersion = 1; /* We create only version 1 images at the moment. */
1357	pImage->cbSize = cbSize;
1358	pImage->cbCluster = QCOW_CLUSTER_SIZE_DEFAULT;
1359	pImage->cbL2Table = qcowCluster2Byte(pImage, QCOW_L2_CLUSTERS_DEFAULT);
1360	pImage->cL2TableEntries = pImage->cbL2Table / sizeof(uint64_t);
1361	pImage->cL1TableEntries = cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1362	if (cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1363	pImage->cL1TableEntries++;
1364	pImage->cbL1Table = pImage->cL1TableEntries * sizeof(uint64_t);
1365	pImage->offL1Table = QCOW_V1_HDR_SIZE;
1366	pImage->cbBackingFilename = 0;
1367	pImage->offBackingFilename = 0;
1368	pImage->offNextCluster = RT_ALIGN_64(QCOW_V1_HDR_SIZE + pImage->cbL1Table, pImage->cbCluster);
1369	qcowTableMasksInit(pImage);
1370
1371	/* Init L1 table. */
1372	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1373	if (!pImage->paL1Table)
1374	{
1375	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS, N_("QCow: cannot allocate memory for L1 table of image '%s'"),
1376	pImage->pszFilename);
1377	goto out;
1378	}
1379
1380	rc = qcowL2TblCacheCreate(pImage);
1381	if (RT_FAILURE(rc))
1382	{
1383	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: Failed to create L2 cache for image '%s'"),
1384	pImage->pszFilename);
1385	goto out;
1386	}
1387
1388	if (RT_SUCCESS(rc) && pfnProgress)
1389	pfnProgress(pvUser, uPercentStart + uPercentSpan * 98 / 100);
1390
1391	rc = qcowFlushImage(pImage);
1392	if (RT_SUCCESS(rc))
1393	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pImage->offNextCluster);
1394
1395	out:
1396	if (RT_SUCCESS(rc) && pfnProgress)
1397	pfnProgress(pvUser, uPercentStart + uPercentSpan);
1398
1399	if (RT_FAILURE(rc))
1400	qcowFreeImage(pImage, rc != VERR_ALREADY_EXISTS);
1401	return rc;
1402	}
1403
1404	/**
1405	* Rollback anything done during async cluster allocation.
1406	*
1407	* @returns VBox status code.
1408	* @param pImage The image instance data.
1409	* @param pIoCtx The I/O context.
1410	* @param pClusterAlloc The cluster allocation to rollback.
1411	*/
1412	static int qcowAsyncClusterAllocRollback(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, PQCOWCLUSTERASYNCALLOC pClusterAlloc)
1413	{
1414	int rc = VINF_SUCCESS;
1415
1416	switch (pClusterAlloc->enmAllocState)
1417	{
1418	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1419	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1420	{
1421	/* Assumption right now is that the L1 table is not modified if the link fails. */
1422	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1423	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1424	qcowL2TblCacheEntryFree(pImage, pClusterAlloc->pL2Entry); /* Free it, it is not in the cache yet. */
1425	}
1426	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1427	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1428	{
1429	/* Assumption right now is that the L2 table is not modified if the link fails. */
1430	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1431	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1432	break;
1433	}
1434	default:
1435	AssertMsgFailed(("Invalid cluster allocation state %d\n", pClusterAlloc->enmAllocState));
1436	rc = VERR_INVALID_STATE;
1437	}
1438
1439	RTMemFree(pClusterAlloc);
1440	return rc;
1441	}
1442
1443	/**
1444	* Updates the state of the async cluster allocation.
1445	*
1446	* @returns VBox status code.
1447	* @param pBackendData The opaque backend data.
1448	* @param pIoCtx I/O context associated with this request.
1449	* @param pvUser Opaque user data passed during a read/write request.
1450	* @param rcReq Status code for the completed request.
1451	*/
1452	static DECLCALLBACK(int) qcowAsyncClusterAllocUpdate(void pBackendData, PVDIOCTX pIoCtx, void pvUser, int rcReq)
1453	{
1454	int rc = VINF_SUCCESS;
1455	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1456	PQCOWCLUSTERASYNCALLOC pClusterAlloc = (PQCOWCLUSTERASYNCALLOC)pvUser;
1457
1458	if (RT_FAILURE(rcReq))
1459	return qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1460
1461	AssertPtr(pClusterAlloc->pL2Entry);
1462
1463	switch (pClusterAlloc->enmAllocState)
1464	{
1465	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1466	{
1467	uint64_t offUpdateLe = RT_H2BE_U64(pClusterAlloc->pL2Entry->offL2Tbl);
1468
1469	/* Update the link in the on disk L1 table now. */
1470	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_LINK;
1471	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
1472	pImage->offL1Table + pClusterAlloc->idxL1*sizeof(uint64_t),
1473	&offUpdateLe, sizeof(uint64_t), pIoCtx,
1474	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1475	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1476	break;
1477	else if (RT_FAILURE(rc))
1478	{
1479	/* Rollback. */
1480	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1481	break;
1482	}
1483	/* Success, fall through. */
1484	}
1485	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1486	{
1487	/* L2 link updated in L1 , save L2 entry in cache and allocate new user data cluster. */
1488	uint64_t offData = qcowClusterAllocate(pImage, 1);
1489
1490	/* Update the link in the in memory L1 table now. */
1491	pImage->paL1Table[pClusterAlloc->idxL1] = pClusterAlloc->pL2Entry->offL2Tbl;
1492	qcowL2TblCacheEntryInsert(pImage, pClusterAlloc->pL2Entry);
1493
1494	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
1495	pClusterAlloc->offNextClusterOld = offData;
1496	pClusterAlloc->offClusterNew = offData;
1497
1498	/* Write data. */
1499	rc = vdIfIoIntFileWriteUserAsync(pImage->pIfIo, pImage->pStorage,
1500	offData, pIoCtx, pClusterAlloc->cbToWrite,
1501	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1502	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1503	break;
1504	else if (RT_FAILURE(rc))
1505	{
1506	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1507	RTMemFree(pClusterAlloc);
1508	break;
1509	}
1510	}
1511	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1512	{
1513	uint64_t offUpdateLe = RT_H2BE_U64(pClusterAlloc->offClusterNew);
1514
1515	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_LINK;
1516
1517	/* Link L2 table and update it. */
1518	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
1519	pImage->paL1Table[pClusterAlloc->idxL1] + pClusterAlloc->idxL2*sizeof(uint64_t),
1520	&offUpdateLe, sizeof(uint64_t), pIoCtx,
1521	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1522	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1523	break;
1524	else if (RT_FAILURE(rc))
1525	{
1526	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1527	RTMemFree(pClusterAlloc);
1528	break;
1529	}
1530	}
1531	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1532	{
1533	/* Everything done without errors, signal completion. */
1534	pClusterAlloc->pL2Entry->paL2Tbl[pClusterAlloc->idxL2] = pClusterAlloc->offClusterNew;
1535	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry);
1536	RTMemFree(pClusterAlloc);
1537	rc = VINF_SUCCESS;
1538	break;
1539	}
1540	default:
1541	AssertMsgFailed(("Invalid async cluster allocation state %d\n",
1542	pClusterAlloc->enmAllocState));
1543	}
1544
1545	return rc;
1546	}
1547
1548	/** @copydoc VBOXHDDBACKEND::pfnCheckIfValid */
1549	static int qcowCheckIfValid(const char *pszFilename, PVDINTERFACE pVDIfsDisk,
1550	PVDINTERFACE pVDIfsImage, VDTYPE *penmType)
1551	{
1552	LogFlowFunc(("pszFilename=\"%s\" pVDIfsDisk=%#p pVDIfsImage=%#p\n", pszFilename, pVDIfsDisk, pVDIfsImage));
1553	PVDIOSTORAGE pStorage = NULL;
1554	uint64_t cbFile;
1555	int rc = VINF_SUCCESS;
1556
1557	/* Get I/O interface. */
1558	PVDINTERFACEIOINT pIfIo = VDIfIoIntGet(pVDIfsImage);
1559	AssertPtrReturn(pIfIo, VERR_INVALID_PARAMETER);
1560
1561	if ( !VALID_PTR(pszFilename)
1562	\|\| !*pszFilename)
1563	{
1564	rc = VERR_INVALID_PARAMETER;
1565	goto out;
1566	}
1567
1568	/*
1569	* Open the file and read the footer.
1570	*/
1571	rc = vdIfIoIntFileOpen(pIfIo, pszFilename,
1572	VDOpenFlagsToFileOpenFlags(VD_OPEN_FLAGS_READONLY,
1573	false /* fCreate */),
1574	&pStorage);
1575	if (RT_SUCCESS(rc))
1576	rc = vdIfIoIntFileGetSize(pIfIo, pStorage, &cbFile);
1577
1578	if ( RT_SUCCESS(rc)
1579	&& cbFile > sizeof(QCowHeader))
1580	{
1581	QCowHeader Header;
1582
1583	rc = vdIfIoIntFileReadSync(pIfIo, pStorage, 0, &Header, sizeof(Header), NULL);
1584	if ( RT_SUCCESS(rc)
1585	&& qcowHdrConvertToHostEndianess(&Header))
1586	{
1587	*penmType = VDTYPE_HDD;
1588	rc = VINF_SUCCESS;
1589	}
1590	else
1591	rc = VERR_VD_GEN_INVALID_HEADER;
1592	}
1593	else
1594	rc = VERR_VD_GEN_INVALID_HEADER;
1595
1596	if (pStorage)
1597	vdIfIoIntFileClose(pIfIo, pStorage);
1598
1599	out:
1600	LogFlowFunc(("returns %Rrc\n", rc));
1601	return rc;
1602	}
1603
1604	/** @copydoc VBOXHDDBACKEND::pfnOpen */
1605	static int qcowOpen(const char *pszFilename, unsigned uOpenFlags,
1606	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1607	VDTYPE enmType, void **ppBackendData)
1608	{
1609	LogFlowFunc(("pszFilename=\"%s\" uOpenFlags=%#x pVDIfsDisk=%#p pVDIfsImage=%#p ppBackendData=%#p\n", pszFilename, uOpenFlags, pVDIfsDisk, pVDIfsImage, ppBackendData));
1610	int rc;
1611	PQCOWIMAGE pImage;
1612
1613	/* Check open flags. All valid flags are supported. */
1614	if (uOpenFlags & ~VD_OPEN_FLAGS_MASK)
1615	{
1616	rc = VERR_INVALID_PARAMETER;
1617	goto out;
1618	}
1619
1620	/* Check remaining arguments. */
1621	if ( !VALID_PTR(pszFilename)
1622	\|\| !*pszFilename)
1623	{
1624	rc = VERR_INVALID_PARAMETER;
1625	goto out;
1626	}
1627
1628
1629	pImage = (PQCOWIMAGE)RTMemAllocZ(sizeof(QCOWIMAGE));
1630	if (!pImage)
1631	{
1632	rc = VERR_NO_MEMORY;
1633	goto out;
1634	}
1635	pImage->pszFilename = pszFilename;
1636	pImage->pStorage = NULL;
1637	pImage->pVDIfsDisk = pVDIfsDisk;
1638	pImage->pVDIfsImage = pVDIfsImage;
1639
1640	rc = qcowOpenImage(pImage, uOpenFlags);
1641	if (RT_SUCCESS(rc))
1642	*ppBackendData = pImage;
1643	else
1644	RTMemFree(pImage);
1645
1646	out:
1647	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1648	return rc;
1649	}
1650
1651	/** @copydoc VBOXHDDBACKEND::pfnCreate */
1652	static int qcowCreate(const char *pszFilename, uint64_t cbSize,
1653	unsigned uImageFlags, const char *pszComment,
1654	PCVDGEOMETRY pPCHSGeometry, PCVDGEOMETRY pLCHSGeometry,
1655	PCRTUUID pUuid, unsigned uOpenFlags,
1656	unsigned uPercentStart, unsigned uPercentSpan,
1657	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1658	PVDINTERFACE pVDIfsOperation, void **ppBackendData)
1659	{
1660	LogFlowFunc(("pszFilename=\"%s\" cbSize=%llu uImageFlags=%#x pszComment=\"%s\" pPCHSGeometry=%#p pLCHSGeometry=%#p Uuid=%RTuuid uOpenFlags=%#x uPercentStart=%u uPercentSpan=%u pVDIfsDisk=%#p pVDIfsImage=%#p pVDIfsOperation=%#p ppBackendData=%#p",
1661	pszFilename, cbSize, uImageFlags, pszComment, pPCHSGeometry, pLCHSGeometry, pUuid, uOpenFlags, uPercentStart, uPercentSpan, pVDIfsDisk, pVDIfsImage, pVDIfsOperation, ppBackendData));
1662	int rc;
1663	PQCOWIMAGE pImage;
1664
1665	PFNVDPROGRESS pfnProgress = NULL;
1666	void *pvUser = NULL;
1667	PVDINTERFACEPROGRESS pIfProgress = VDIfProgressGet(pVDIfsOperation);
1668	if (pIfProgress)
1669	{
1670	pfnProgress = pIfProgress->pfnProgress;
1671	pvUser = pIfProgress->Core.pvUser;
1672	}
1673
1674	/* Check open flags. All valid flags are supported. */
1675	if (uOpenFlags & ~VD_OPEN_FLAGS_MASK)
1676	{
1677	rc = VERR_INVALID_PARAMETER;
1678	goto out;
1679	}
1680
1681	/* Check remaining arguments. */
1682	if ( !VALID_PTR(pszFilename)
1683	\|\| !*pszFilename
1684	\|\| !VALID_PTR(pPCHSGeometry)
1685	\|\| !VALID_PTR(pLCHSGeometry))
1686	{
1687	rc = VERR_INVALID_PARAMETER;
1688	goto out;
1689	}
1690
1691	pImage = (PQCOWIMAGE)RTMemAllocZ(sizeof(QCOWIMAGE));
1692	if (!pImage)
1693	{
1694	rc = VERR_NO_MEMORY;
1695	goto out;
1696	}
1697	pImage->pszFilename = pszFilename;
1698	pImage->pStorage = NULL;
1699	pImage->pVDIfsDisk = pVDIfsDisk;
1700	pImage->pVDIfsImage = pVDIfsImage;
1701
1702	rc = qcowCreateImage(pImage, cbSize, uImageFlags, pszComment,
1703	pPCHSGeometry, pLCHSGeometry, uOpenFlags,
1704	pfnProgress, pvUser, uPercentStart, uPercentSpan);
1705	if (RT_SUCCESS(rc))
1706	{
1707	/* So far the image is opened in read/write mode. Make sure the
1708	* image is opened in read-only mode if the caller requested that. */
1709	if (uOpenFlags & VD_OPEN_FLAGS_READONLY)
1710	{
1711	qcowFreeImage(pImage, false);
1712	rc = qcowOpenImage(pImage, uOpenFlags);
1713	if (RT_FAILURE(rc))
1714	{
1715	RTMemFree(pImage);
1716	goto out;
1717	}
1718	}
1719	*ppBackendData = pImage;
1720	}
1721	else
1722	RTMemFree(pImage);
1723
1724	out:
1725	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1726	return rc;
1727	}
1728
1729	/** @copydoc VBOXHDDBACKEND::pfnRename */
1730	static int qcowRename(void pBackendData, const char pszFilename)
1731	{
1732	LogFlowFunc(("pBackendData=%#p pszFilename=%#p\n", pBackendData, pszFilename));
1733	int rc = VINF_SUCCESS;
1734	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1735
1736	/* Check arguments. */
1737	if ( !pImage
1738	\|\| !pszFilename
1739	\|\| !*pszFilename)
1740	{
1741	rc = VERR_INVALID_PARAMETER;
1742	goto out;
1743	}
1744
1745	/* Close the image. */
1746	rc = qcowFreeImage(pImage, false);
1747	if (RT_FAILURE(rc))
1748	goto out;
1749
1750	/* Rename the file. */
1751	rc = vdIfIoIntFileMove(pImage->pIfIo, pImage->pszFilename, pszFilename, 0);
1752	if (RT_FAILURE(rc))
1753	{
1754	/* The move failed, try to reopen the original image. */
1755	int rc2 = qcowOpenImage(pImage, pImage->uOpenFlags);
1756	if (RT_FAILURE(rc2))
1757	rc = rc2;
1758
1759	goto out;
1760	}
1761
1762	/* Update pImage with the new information. */
1763	pImage->pszFilename = pszFilename;
1764
1765	/* Open the old image with new name. */
1766	rc = qcowOpenImage(pImage, pImage->uOpenFlags);
1767	if (RT_FAILURE(rc))
1768	goto out;
1769
1770	out:
1771	LogFlowFunc(("returns %Rrc\n", rc));
1772	return rc;
1773	}
1774
1775	/** @copydoc VBOXHDDBACKEND::pfnClose */
1776	static int qcowClose(void *pBackendData, bool fDelete)
1777	{
1778	LogFlowFunc(("pBackendData=%#p fDelete=%d\n", pBackendData, fDelete));
1779	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1780	int rc;
1781
1782	rc = qcowFreeImage(pImage, fDelete);
1783	RTMemFree(pImage);
1784
1785	LogFlowFunc(("returns %Rrc\n", rc));
1786	return rc;
1787	}
1788
1789	/** @copydoc VBOXHDDBACKEND::pfnRead */
1790	static int qcowRead(void pBackendData, uint64_t uOffset, void pvBuf,
1791	size_t cbToRead, size_t *pcbActuallyRead)
1792	{
1793	LogFlowFunc(("pBackendData=%#p uOffset=%llu pvBuf=%#p cbToRead=%zu pcbActuallyRead=%#p\n",
1794	pBackendData, uOffset, pvBuf, cbToRead, pcbActuallyRead));
1795	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1796	uint32_t offCluster = 0;
1797	uint32_t idxL1 = 0;
1798	uint32_t idxL2 = 0;
1799	uint64_t offFile = 0;
1800	int rc;
1801
1802	AssertPtr(pImage);
1803	Assert(uOffset % 512 == 0);
1804	Assert(cbToRead % 512 == 0);
1805
1806	if ( uOffset + cbToRead > pImage->cbSize
1807	\|\| cbToRead == 0)
1808	{
1809	rc = VERR_INVALID_PARAMETER;
1810	goto out;
1811	}
1812
1813	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1814	LogFlowFunc(("idxL1=%u idxL2=%u offCluster=%u\n", idxL1, idxL2, offCluster));
1815
1816	/* Clip read size to remain in the cluster. */
1817	cbToRead = RT_MIN(cbToRead, pImage->cbCluster - offCluster);
1818
1819	/* Get offset in image. */
1820	rc = qcowConvertToImageOffset(pImage, idxL1, idxL2, offCluster, &offFile);
1821	if (RT_SUCCESS(rc))
1822	{
1823	LogFlowFunc(("offFile=%llu\n", offFile));
1824	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage, offFile,
1825	pvBuf, cbToRead, NULL);
1826	}
1827
1828	if ( (RT_SUCCESS(rc) \|\| rc == VERR_VD_BLOCK_FREE)
1829	&& pcbActuallyRead)
1830	*pcbActuallyRead = cbToRead;
1831
1832	out:
1833	LogFlowFunc(("returns %Rrc\n", rc));
1834	return rc;
1835	}
1836
1837	/** @copydoc VBOXHDDBACKEND::pfnWrite */
1838	static int qcowWrite(void pBackendData, uint64_t uOffset, const void pvBuf,
1839	size_t cbToWrite, size_t *pcbWriteProcess,
1840	size_t pcbPreRead, size_t pcbPostRead, unsigned fWrite)
1841	{
1842	LogFlowFunc(("pBackendData=%#p uOffset=%llu pvBuf=%#p cbToWrite=%zu pcbWriteProcess=%#p pcbPreRead=%#p pcbPostRead=%#p\n",
1843	pBackendData, uOffset, pvBuf, cbToWrite, pcbWriteProcess, pcbPreRead, pcbPostRead));
1844	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1845	uint32_t offCluster = 0;
1846	uint32_t idxL1 = 0;
1847	uint32_t idxL2 = 0;
1848	uint64_t offImage = 0;
1849	int rc;
1850
1851	AssertPtr(pImage);
1852	Assert(uOffset % 512 == 0);
1853	Assert(cbToWrite % 512 == 0);
1854
1855	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
1856	{
1857	rc = VERR_VD_IMAGE_READ_ONLY;
1858	goto out;
1859	}
1860
1861	if ( uOffset + cbToWrite > pImage->cbSize
1862	\|\| cbToWrite == 0)
1863	{
1864	rc = VERR_INVALID_PARAMETER;
1865	goto out;
1866	}
1867
1868	/* Convert offset to L1, L2 index and cluster offset. */
1869	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1870
1871	/* Clip write size to remain in the cluster. */
1872	cbToWrite = RT_MIN(cbToWrite, pImage->cbCluster - offCluster);
1873	Assert(!(cbToWrite % 512));
1874
1875	/* Get offset in image. */
1876	rc = qcowConvertToImageOffset(pImage, idxL1, idxL2, offCluster, &offImage);
1877	if (RT_SUCCESS(rc))
1878	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, offImage,
1879	pvBuf, cbToWrite, NULL);
1880	else if (rc == VERR_VD_BLOCK_FREE)
1881	{
1882	if ( cbToWrite == pImage->cbCluster
1883	&& !(fWrite & VD_WRITE_NO_ALLOC))
1884	{
1885	PQCOWL2CACHEENTRY pL2Entry = NULL;
1886
1887	/* Full cluster write to previously unallocated cluster.
1888	* Allocate cluster and write data. */
1889	Assert(!offCluster);
1890
1891	do
1892	{
1893	uint64_t idxUpdateLe = 0;
1894
1895	/* Check if we have to allocate a new cluster for L2 tables. */
1896	if (!pImage->paL1Table[idxL1])
1897	{
1898	uint64_t offL2Tbl = qcowClusterAllocate(pImage, qcowByte2Cluster(pImage, pImage->cbL2Table));
1899
1900	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
1901	if (!pL2Entry)
1902	{
1903	rc = VERR_NO_MEMORY;
1904	break;
1905	}
1906
1907	pL2Entry->offL2Tbl = offL2Tbl;
1908	memset(pL2Entry->paL2Tbl, 0, pImage->cbL2Table);
1909	qcowL2TblCacheEntryInsert(pImage, pL2Entry);
1910
1911	/*
1912	* Write the L2 table first and link to the L1 table afterwards.
1913	* If something unexpected happens the worst case which can happen
1914	* is a leak of some clusters.
1915	*/
1916	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, offL2Tbl,
1917	pL2Entry->paL2Tbl, pImage->cbL2Table, NULL);
1918	if (RT_FAILURE(rc))
1919	break;
1920
1921	/* Write the L1 link now. */
1922	pImage->paL1Table[idxL1] = offL2Tbl;
1923	idxUpdateLe = RT_H2BE_U64(offL2Tbl);
1924	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
1925	pImage->offL1Table + idxL1*sizeof(uint64_t),
1926	&idxUpdateLe, sizeof(uint64_t), NULL);
1927	if (RT_FAILURE(rc))
1928	break;
1929	}
1930	else
1931	rc = qcowL2TblCacheFetch(pImage, pImage->paL1Table[idxL1], &pL2Entry);
1932
1933	if (RT_SUCCESS(rc))
1934	{
1935	/* Allocate new cluster for the data. */
1936	uint64_t offData = qcowClusterAllocate(pImage, 1);
1937
1938	/* Write data. */
1939	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
1940	offData, pvBuf, cbToWrite, NULL);
1941	if (RT_FAILURE(rc))
1942	break;
1943
1944	/* Link L2 table and update it. */
1945	pL2Entry->paL2Tbl[idxL2] = offData;
1946	idxUpdateLe = RT_H2BE_U64(offData);
1947	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
1948	pImage->paL1Table[idxL1] + idxL2*sizeof(uint64_t),
1949	&idxUpdateLe, sizeof(uint64_t), NULL);
1950	qcowL2TblCacheEntryRelease(pL2Entry);
1951	}
1952
1953	} while (0);
1954
1955	*pcbPreRead = 0;
1956	*pcbPostRead = 0;
1957	}
1958	else
1959	{
1960	/* Trying to do a partial write to an unallocated cluster. Don't do
1961	* anything except letting the upper layer know what to do. */
1962	*pcbPreRead = offCluster;
1963	pcbPostRead = pImage->cbCluster - cbToWrite - pcbPreRead;
1964	}
1965	}
1966
1967	if (pcbWriteProcess)
1968	*pcbWriteProcess = cbToWrite;
1969
1970	out:
1971	LogFlowFunc(("returns %Rrc\n", rc));
1972	return rc;
1973	}
1974
1975	/** @copydoc VBOXHDDBACKEND::pfnFlush */
1976	static int qcowFlush(void *pBackendData)
1977	{
1978	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1979	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1980	int rc;
1981
1982	rc = qcowFlushImage(pImage);
1983	LogFlowFunc(("returns %Rrc\n", rc));
1984	return rc;
1985	}
1986
1987	/** @copydoc VBOXHDDBACKEND::pfnGetVersion */
1988	static unsigned qcowGetVersion(void *pBackendData)
1989	{
1990	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1991	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1992
1993	AssertPtr(pImage);
1994
1995	if (pImage)
1996	return pImage->uVersion;
1997	else
1998	return 0;
1999	}
2000
2001	/** @copydoc VBOXHDDBACKEND::pfnGetSize */
2002	static uint64_t qcowGetSize(void *pBackendData)
2003	{
2004	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2005	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2006	uint64_t cb = 0;
2007
2008	AssertPtr(pImage);
2009
2010	if (pImage && pImage->pStorage)
2011	cb = pImage->cbSize;
2012
2013	LogFlowFunc(("returns %llu\n", cb));
2014	return cb;
2015	}
2016
2017	/** @copydoc VBOXHDDBACKEND::pfnGetFileSize */
2018	static uint64_t qcowGetFileSize(void *pBackendData)
2019	{
2020	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2021	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2022	uint64_t cb = 0;
2023
2024	AssertPtr(pImage);
2025
2026	if (pImage)
2027	{
2028	uint64_t cbFile;
2029	if (pImage->pStorage)
2030	{
2031	int rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
2032	if (RT_SUCCESS(rc))
2033	cb += cbFile;
2034	}
2035	}
2036
2037	LogFlowFunc(("returns %lld\n", cb));
2038	return cb;
2039	}
2040
2041	/** @copydoc VBOXHDDBACKEND::pfnGetPCHSGeometry */
2042	static int qcowGetPCHSGeometry(void *pBackendData,
2043	PVDGEOMETRY pPCHSGeometry)
2044	{
2045	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p\n", pBackendData, pPCHSGeometry));
2046	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2047	int rc;
2048
2049	AssertPtr(pImage);
2050
2051	if (pImage)
2052	{
2053	if (pImage->PCHSGeometry.cCylinders)
2054	{
2055	*pPCHSGeometry = pImage->PCHSGeometry;
2056	rc = VINF_SUCCESS;
2057	}
2058	else
2059	rc = VERR_VD_GEOMETRY_NOT_SET;
2060	}
2061	else
2062	rc = VERR_VD_NOT_OPENED;
2063
2064	LogFlowFunc(("returns %Rrc (PCHS=%u/%u/%u)\n", rc, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
2065	return rc;
2066	}
2067
2068	/** @copydoc VBOXHDDBACKEND::pfnSetPCHSGeometry */
2069	static int qcowSetPCHSGeometry(void *pBackendData,
2070	PCVDGEOMETRY pPCHSGeometry)
2071	{
2072	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p PCHS=%u/%u/%u\n", pBackendData, pPCHSGeometry, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
2073	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2074	int rc;
2075
2076	AssertPtr(pImage);
2077
2078	if (pImage)
2079	{
2080	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2081	{
2082	rc = VERR_VD_IMAGE_READ_ONLY;
2083	goto out;
2084	}
2085
2086	pImage->PCHSGeometry = *pPCHSGeometry;
2087	rc = VINF_SUCCESS;
2088	}
2089	else
2090	rc = VERR_VD_NOT_OPENED;
2091
2092	out:
2093	LogFlowFunc(("returns %Rrc\n", rc));
2094	return rc;
2095	}
2096
2097	/** @copydoc VBOXHDDBACKEND::pfnGetLCHSGeometry */
2098	static int qcowGetLCHSGeometry(void *pBackendData,
2099	PVDGEOMETRY pLCHSGeometry)
2100	{
2101	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p\n", pBackendData, pLCHSGeometry));
2102	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2103	int rc;
2104
2105	AssertPtr(pImage);
2106
2107	if (pImage)
2108	{
2109	if (pImage->LCHSGeometry.cCylinders)
2110	{
2111	*pLCHSGeometry = pImage->LCHSGeometry;
2112	rc = VINF_SUCCESS;
2113	}
2114	else
2115	rc = VERR_VD_GEOMETRY_NOT_SET;
2116	}
2117	else
2118	rc = VERR_VD_NOT_OPENED;
2119
2120	LogFlowFunc(("returns %Rrc (LCHS=%u/%u/%u)\n", rc, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2121	return rc;
2122	}
2123
2124	/** @copydoc VBOXHDDBACKEND::pfnSetLCHSGeometry */
2125	static int qcowSetLCHSGeometry(void *pBackendData,
2126	PCVDGEOMETRY pLCHSGeometry)
2127	{
2128	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p LCHS=%u/%u/%u\n", pBackendData, pLCHSGeometry, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2129	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2130	int rc;
2131
2132	AssertPtr(pImage);
2133
2134	if (pImage)
2135	{
2136	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2137	{
2138	rc = VERR_VD_IMAGE_READ_ONLY;
2139	goto out;
2140	}
2141
2142	pImage->LCHSGeometry = *pLCHSGeometry;
2143	rc = VINF_SUCCESS;
2144	}
2145	else
2146	rc = VERR_VD_NOT_OPENED;
2147
2148	out:
2149	LogFlowFunc(("returns %Rrc\n", rc));
2150	return rc;
2151	}
2152
2153	/** @copydoc VBOXHDDBACKEND::pfnGetImageFlags */
2154	static unsigned qcowGetImageFlags(void *pBackendData)
2155	{
2156	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2157	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2158	unsigned uImageFlags;
2159
2160	AssertPtr(pImage);
2161
2162	if (pImage)
2163	uImageFlags = pImage->uImageFlags;
2164	else
2165	uImageFlags = 0;
2166
2167	LogFlowFunc(("returns %#x\n", uImageFlags));
2168	return uImageFlags;
2169	}
2170
2171	/** @copydoc VBOXHDDBACKEND::pfnGetOpenFlags */
2172	static unsigned qcowGetOpenFlags(void *pBackendData)
2173	{
2174	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2175	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2176	unsigned uOpenFlags;
2177
2178	AssertPtr(pImage);
2179
2180	if (pImage)
2181	uOpenFlags = pImage->uOpenFlags;
2182	else
2183	uOpenFlags = 0;
2184
2185	LogFlowFunc(("returns %#x\n", uOpenFlags));
2186	return uOpenFlags;
2187	}
2188
2189	/** @copydoc VBOXHDDBACKEND::pfnSetOpenFlags */
2190	static int qcowSetOpenFlags(void *pBackendData, unsigned uOpenFlags)
2191	{
2192	LogFlowFunc(("pBackendData=%#p\n uOpenFlags=%#x", pBackendData, uOpenFlags));
2193	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2194	int rc;
2195
2196	/* Image must be opened and the new flags must be valid. */
2197	if (!pImage \|\| (uOpenFlags & ~( VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_INFO
2198	\| VD_OPEN_FLAGS_ASYNC_IO \| VD_OPEN_FLAGS_SKIP_CONSISTENCY_CHECKS)))
2199	{
2200	rc = VERR_INVALID_PARAMETER;
2201	goto out;
2202	}
2203
2204	/* Implement this operation via reopening the image. */
2205	rc = qcowFreeImage(pImage, false);
2206	if (RT_FAILURE(rc))
2207	goto out;
2208	rc = qcowOpenImage(pImage, uOpenFlags);
2209
2210	out:
2211	LogFlowFunc(("returns %Rrc\n", rc));
2212	return rc;
2213	}
2214
2215	/** @copydoc VBOXHDDBACKEND::pfnGetComment */
2216	static int qcowGetComment(void pBackendData, char pszComment,
2217	size_t cbComment)
2218	{
2219	LogFlowFunc(("pBackendData=%#p pszComment=%#p cbComment=%zu\n", pBackendData, pszComment, cbComment));
2220	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2221	int rc;
2222
2223	AssertPtr(pImage);
2224
2225	if (pImage)
2226	rc = VERR_NOT_SUPPORTED;
2227	else
2228	rc = VERR_VD_NOT_OPENED;
2229
2230	LogFlowFunc(("returns %Rrc comment='%s'\n", rc, pszComment));
2231	return rc;
2232	}
2233
2234	/** @copydoc VBOXHDDBACKEND::pfnSetComment */
2235	static int qcowSetComment(void pBackendData, const char pszComment)
2236	{
2237	LogFlowFunc(("pBackendData=%#p pszComment=\"%s\"\n", pBackendData, pszComment));
2238	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2239	int rc;
2240
2241	AssertPtr(pImage);
2242
2243	if (pImage)
2244	{
2245	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2246	rc = VERR_VD_IMAGE_READ_ONLY;
2247	else
2248	rc = VERR_NOT_SUPPORTED;
2249	}
2250	else
2251	rc = VERR_VD_NOT_OPENED;
2252
2253	LogFlowFunc(("returns %Rrc\n", rc));
2254	return rc;
2255	}
2256
2257	/** @copydoc VBOXHDDBACKEND::pfnGetUuid */
2258	static int qcowGetUuid(void *pBackendData, PRTUUID pUuid)
2259	{
2260	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2261	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2262	int rc;
2263
2264	AssertPtr(pImage);
2265
2266	if (pImage)
2267	rc = VERR_NOT_SUPPORTED;
2268	else
2269	rc = VERR_VD_NOT_OPENED;
2270
2271	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2272	return rc;
2273	}
2274
2275	/** @copydoc VBOXHDDBACKEND::pfnSetUuid */
2276	static int qcowSetUuid(void *pBackendData, PCRTUUID pUuid)
2277	{
2278	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2279	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2280	int rc;
2281
2282	LogFlowFunc(("%RTuuid\n", pUuid));
2283	AssertPtr(pImage);
2284
2285	if (pImage)
2286	{
2287	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2288	rc = VERR_NOT_SUPPORTED;
2289	else
2290	rc = VERR_VD_IMAGE_READ_ONLY;
2291	}
2292	else
2293	rc = VERR_VD_NOT_OPENED;
2294
2295	LogFlowFunc(("returns %Rrc\n", rc));
2296	return rc;
2297	}
2298
2299	/** @copydoc VBOXHDDBACKEND::pfnGetModificationUuid */
2300	static int qcowGetModificationUuid(void *pBackendData, PRTUUID pUuid)
2301	{
2302	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2303	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2304	int rc;
2305
2306	AssertPtr(pImage);
2307
2308	if (pImage)
2309	rc = VERR_NOT_SUPPORTED;
2310	else
2311	rc = VERR_VD_NOT_OPENED;
2312
2313	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2314	return rc;
2315	}
2316
2317	/** @copydoc VBOXHDDBACKEND::pfnSetModificationUuid */
2318	static int qcowSetModificationUuid(void *pBackendData, PCRTUUID pUuid)
2319	{
2320	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2321	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2322	int rc;
2323
2324	AssertPtr(pImage);
2325
2326	if (pImage)
2327	{
2328	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2329	rc = VERR_NOT_SUPPORTED;
2330	else
2331	rc = VERR_VD_IMAGE_READ_ONLY;
2332	}
2333	else
2334	rc = VERR_VD_NOT_OPENED;
2335
2336	LogFlowFunc(("returns %Rrc\n", rc));
2337	return rc;
2338	}
2339
2340	/** @copydoc VBOXHDDBACKEND::pfnGetParentUuid */
2341	static int qcowGetParentUuid(void *pBackendData, PRTUUID pUuid)
2342	{
2343	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2344	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2345	int rc;
2346
2347	AssertPtr(pImage);
2348
2349	if (pImage)
2350	rc = VERR_NOT_SUPPORTED;
2351	else
2352	rc = VERR_VD_NOT_OPENED;
2353
2354	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2355	return rc;
2356	}
2357
2358	/** @copydoc VBOXHDDBACKEND::pfnSetParentUuid */
2359	static int qcowSetParentUuid(void *pBackendData, PCRTUUID pUuid)
2360	{
2361	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2362	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2363	int rc;
2364
2365	AssertPtr(pImage);
2366
2367	if (pImage)
2368	{
2369	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2370	rc = VERR_NOT_SUPPORTED;
2371	else
2372	rc = VERR_VD_IMAGE_READ_ONLY;
2373	}
2374	else
2375	rc = VERR_VD_NOT_OPENED;
2376
2377	LogFlowFunc(("returns %Rrc\n", rc));
2378	return rc;
2379	}
2380
2381	/** @copydoc VBOXHDDBACKEND::pfnGetParentModificationUuid */
2382	static int qcowGetParentModificationUuid(void *pBackendData, PRTUUID pUuid)
2383	{
2384	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2385	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2386	int rc;
2387
2388	AssertPtr(pImage);
2389
2390	if (pImage)
2391	rc = VERR_NOT_SUPPORTED;
2392	else
2393	rc = VERR_VD_NOT_OPENED;
2394
2395	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2396	return rc;
2397	}
2398
2399	/** @copydoc VBOXHDDBACKEND::pfnSetParentModificationUuid */
2400	static int qcowSetParentModificationUuid(void *pBackendData, PCRTUUID pUuid)
2401	{
2402	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2403	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2404	int rc;
2405
2406	AssertPtr(pImage);
2407
2408	if (pImage)
2409	{
2410	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2411	rc = VERR_NOT_SUPPORTED;
2412	else
2413	rc = VERR_VD_IMAGE_READ_ONLY;
2414	}
2415	else
2416	rc = VERR_VD_NOT_OPENED;
2417
2418	LogFlowFunc(("returns %Rrc\n", rc));
2419	return rc;
2420	}
2421
2422	/** @copydoc VBOXHDDBACKEND::pfnDump */
2423	static void qcowDump(void *pBackendData)
2424	{
2425	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2426
2427	AssertPtr(pImage);
2428	if (pImage)
2429	{
2430	vdIfErrorMessage(pImage->pIfError, "Header: Geometry PCHS=%u/%u/%u LCHS=%u/%u/%u cSector=%llu\n",
2431	pImage->PCHSGeometry.cCylinders, pImage->PCHSGeometry.cHeads, pImage->PCHSGeometry.cSectors,
2432	pImage->LCHSGeometry.cCylinders, pImage->LCHSGeometry.cHeads, pImage->LCHSGeometry.cSectors,
2433	pImage->cbSize / 512);
2434	}
2435	}
2436
2437	/** @copydoc VBOXHDDBACKEND::pfnGetParentFilename */
2438	static int qcowGetParentFilename(void pBackendData, char *ppszParentFilename)
2439	{
2440	int rc = VINF_SUCCESS;
2441	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2442
2443	AssertPtr(pImage);
2444	if (pImage)
2445	if (pImage->pszFilename)
2446	*ppszParentFilename = RTStrDup(pImage->pszBackingFilename);
2447	else
2448	rc = VERR_NOT_SUPPORTED;
2449	else
2450	rc = VERR_VD_NOT_OPENED;
2451
2452	LogFlowFunc(("returns %Rrc\n", rc));
2453	return rc;
2454	}
2455
2456	/** @copydoc VBOXHDDBACKEND::pfnSetParentFilename */
2457	static int qcowSetParentFilename(void pBackendData, const char pszParentFilename)
2458	{
2459	int rc = VINF_SUCCESS;
2460	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2461
2462	AssertPtr(pImage);
2463	if (pImage)
2464	{
2465	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2466	rc = VERR_VD_IMAGE_READ_ONLY;
2467	else if ( pImage->pszBackingFilename
2468	&& (strlen(pszParentFilename) > pImage->cbBackingFilename))
2469	rc = VERR_NOT_SUPPORTED; /* The new filename is longer than the old one. */
2470	else
2471	{
2472	if (pImage->pszBackingFilename)
2473	RTStrFree(pImage->pszBackingFilename);
2474	pImage->pszBackingFilename = RTStrDup(pszParentFilename);
2475	if (!pImage->pszBackingFilename)
2476	rc = VERR_NO_MEMORY;
2477	else
2478	{
2479	if (!pImage->offBackingFilename)
2480	{
2481	/* Allocate new cluster. */
2482	uint64_t offData = qcowClusterAllocate(pImage, 1);
2483
2484	Assert((offData & UINT32_MAX) == offData);
2485	pImage->offBackingFilename = (uint32_t)offData;
2486	pImage->cbBackingFilename = strlen(pszParentFilename);
2487	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage,
2488	offData + pImage->cbCluster);
2489	}
2490
2491	if (RT_SUCCESS(rc))
2492	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
2493	pImage->offBackingFilename,
2494	pImage->pszBackingFilename,
2495	strlen(pImage->pszBackingFilename),
2496	NULL);
2497	}
2498	}
2499	}
2500	else
2501	rc = VERR_VD_NOT_OPENED;
2502
2503	LogFlowFunc(("returns %Rrc\n", rc));
2504	return rc;
2505	}
2506
2507	static int qcowAsyncRead(void *pBackendData, uint64_t uOffset, size_t cbToRead,
2508	PVDIOCTX pIoCtx, size_t *pcbActuallyRead)
2509	{
2510	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToRead=%zu pcbActuallyRead=%#p\n",
2511	pBackendData, uOffset, pIoCtx, cbToRead, pcbActuallyRead));
2512	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2513	uint32_t offCluster = 0;
2514	uint32_t idxL1 = 0;
2515	uint32_t idxL2 = 0;
2516	uint64_t offFile = 0;
2517	int rc;
2518
2519	AssertPtr(pImage);
2520	Assert(uOffset % 512 == 0);
2521	Assert(cbToRead % 512 == 0);
2522
2523	if (!VALID_PTR(pIoCtx) \|\| !cbToRead)
2524	{
2525	rc = VERR_INVALID_PARAMETER;
2526	goto out;
2527	}
2528
2529	if ( uOffset + cbToRead > pImage->cbSize
2530	\|\| cbToRead == 0)
2531	{
2532	rc = VERR_INVALID_PARAMETER;
2533	goto out;
2534	}
2535
2536	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
2537
2538	/* Clip read size to remain in the cluster. */
2539	cbToRead = RT_MIN(cbToRead, pImage->cbCluster - offCluster);
2540
2541	/* Get offset in image. */
2542	rc = qcowConvertToImageOffsetAsync(pImage, pIoCtx, idxL1, idxL2, offCluster,
2543	&offFile);
2544	if (RT_SUCCESS(rc))
2545	rc = vdIfIoIntFileReadUserAsync(pImage->pIfIo, pImage->pStorage, offFile,
2546	pIoCtx, cbToRead);
2547
2548	if ( ( RT_SUCCESS(rc)
2549	\|\| rc == VERR_VD_BLOCK_FREE
2550	\|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
2551	&& pcbActuallyRead)
2552	*pcbActuallyRead = cbToRead;
2553
2554	out:
2555	LogFlowFunc(("returns %Rrc\n", rc));
2556	return rc;
2557	}
2558
2559	static int qcowAsyncWrite(void *pBackendData, uint64_t uOffset, size_t cbToWrite,
2560	PVDIOCTX pIoCtx,
2561	size_t pcbWriteProcess, size_t pcbPreRead,
2562	size_t *pcbPostRead, unsigned fWrite)
2563	{
2564	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToWrite=%zu pcbWriteProcess=%#p pcbPreRead=%#p pcbPostRead=%#p\n",
2565	pBackendData, uOffset, pIoCtx, cbToWrite, pcbWriteProcess, pcbPreRead, pcbPostRead));
2566	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2567	uint32_t offCluster = 0;
2568	uint32_t idxL1 = 0;
2569	uint32_t idxL2 = 0;
2570	uint64_t offImage = 0;
2571	int rc = VINF_SUCCESS;
2572
2573	AssertPtr(pImage);
2574	Assert(!(uOffset % 512));
2575	Assert(!(cbToWrite % 512));
2576
2577	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2578	{
2579	rc = VERR_VD_IMAGE_READ_ONLY;
2580	goto out;
2581	}
2582
2583	if (!VALID_PTR(pIoCtx) \|\| !cbToWrite)
2584	{
2585	rc = VERR_INVALID_PARAMETER;
2586	goto out;
2587	}
2588
2589	if ( uOffset + cbToWrite > pImage->cbSize
2590	\|\| cbToWrite == 0)
2591	{
2592	rc = VERR_INVALID_PARAMETER;
2593	goto out;
2594	}
2595
2596	/* Convert offset to L1, L2 index and cluster offset. */
2597	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
2598
2599	/* Clip write size to remain in the cluster. */
2600	cbToWrite = RT_MIN(cbToWrite, pImage->cbCluster - offCluster);
2601	Assert(!(cbToWrite % 512));
2602
2603	/* Get offset in image. */
2604	rc = qcowConvertToImageOffsetAsync(pImage, pIoCtx, idxL1, idxL2, offCluster,
2605	&offImage);
2606	if (RT_SUCCESS(rc))
2607	rc = vdIfIoIntFileWriteUserAsync(pImage->pIfIo, pImage->pStorage,
2608	offImage, pIoCtx, cbToWrite, NULL, NULL);
2609	else if (rc == VERR_VD_BLOCK_FREE)
2610	{
2611	if ( cbToWrite == pImage->cbCluster
2612	&& !(fWrite & VD_WRITE_NO_ALLOC))
2613	{
2614	PQCOWL2CACHEENTRY pL2Entry = NULL;
2615
2616	/* Full cluster write to previously unallocated cluster.
2617	* Allocate cluster and write data. */
2618	Assert(!offCluster);
2619
2620	do
2621	{
2622	uint64_t idxUpdateLe = 0;
2623
2624	/* Check if we have to allocate a new cluster for L2 tables. */
2625	if (!pImage->paL1Table[idxL1])
2626	{
2627	uint64_t offL2Tbl;
2628	PQCOWCLUSTERASYNCALLOC pL2ClusterAlloc = NULL;
2629
2630	/* Allocate new async cluster allocation state. */
2631	pL2ClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
2632	if (RT_UNLIKELY(!pL2ClusterAlloc))
2633	{
2634	rc = VERR_NO_MEMORY;
2635	break;
2636	}
2637
2638	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
2639	if (!pL2Entry)
2640	{
2641	rc = VERR_NO_MEMORY;
2642	RTMemFree(pL2ClusterAlloc);
2643	break;
2644	}
2645
2646	offL2Tbl = qcowClusterAllocate(pImage, qcowByte2Cluster(pImage, pImage->cbL2Table));
2647	pL2Entry->offL2Tbl = offL2Tbl;
2648	memset(pL2Entry->paL2Tbl, 0, pImage->cbL2Table);
2649
2650	pL2ClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC;
2651	pL2ClusterAlloc->offNextClusterOld = offL2Tbl;
2652	pL2ClusterAlloc->offClusterNew = offL2Tbl;
2653	pL2ClusterAlloc->idxL1 = idxL1;
2654	pL2ClusterAlloc->idxL2 = idxL2;
2655	pL2ClusterAlloc->cbToWrite = cbToWrite;
2656	pL2ClusterAlloc->pL2Entry = pL2Entry;
2657
2658	/*
2659	* Write the L2 table first and link to the L1 table afterwards.
2660	* If something unexpected happens the worst case which can happen
2661	* is a leak of some clusters.
2662	*/
2663	rc = vdIfIoIntFileWriteMetaAsync(pImage->pIfIo, pImage->pStorage,
2664	offL2Tbl, pL2Entry->paL2Tbl, pImage->cbL2Table, pIoCtx,
2665	qcowAsyncClusterAllocUpdate, pL2ClusterAlloc);
2666	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
2667	break;
2668	else if (RT_FAILURE(rc))
2669	{
2670	RTMemFree(pL2ClusterAlloc);
2671	qcowL2TblCacheEntryFree(pImage, pL2Entry);
2672	break;
2673	}
2674
2675	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pL2ClusterAlloc, rc);
2676	}
2677	else
2678	{
2679	rc = qcowL2TblCacheFetchAsync(pImage, pIoCtx, pImage->paL1Table[idxL1],
2680	&pL2Entry);
2681
2682	if (RT_SUCCESS(rc))
2683	{
2684	PQCOWCLUSTERASYNCALLOC pDataClusterAlloc = NULL;
2685
2686	/* Allocate new async cluster allocation state. */
2687	pDataClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
2688	if (RT_UNLIKELY(!pDataClusterAlloc))
2689	{
2690	rc = VERR_NO_MEMORY;
2691	break;
2692	}
2693
2694	/* Allocate new cluster for the data. */
2695	uint64_t offData = qcowClusterAllocate(pImage, 1);
2696
2697	pDataClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
2698	pDataClusterAlloc->offNextClusterOld = offData;
2699	pDataClusterAlloc->offClusterNew = offData;
2700	pDataClusterAlloc->idxL1 = idxL1;
2701	pDataClusterAlloc->idxL2 = idxL2;
2702	pDataClusterAlloc->cbToWrite = cbToWrite;
2703	pDataClusterAlloc->pL2Entry = pL2Entry;
2704
2705	/* Write data. */
2706	rc = vdIfIoIntFileWriteUserAsync(pImage->pIfIo, pImage->pStorage,
2707	offData, pIoCtx, cbToWrite,
2708	qcowAsyncClusterAllocUpdate, pDataClusterAlloc);
2709	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
2710	break;
2711	else if (RT_FAILURE(rc))
2712	{
2713	RTMemFree(pDataClusterAlloc);
2714	break;
2715	}
2716
2717	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pDataClusterAlloc, rc);
2718	}
2719	}
2720
2721	} while (0);
2722
2723	*pcbPreRead = 0;
2724	*pcbPostRead = 0;
2725	}
2726	else
2727	{
2728	/* Trying to do a partial write to an unallocated cluster. Don't do
2729	* anything except letting the upper layer know what to do. */
2730	*pcbPreRead = offCluster;
2731	pcbPostRead = pImage->cbCluster - cbToWrite - pcbPreRead;
2732	}
2733	}
2734
2735	if (pcbWriteProcess)
2736	*pcbWriteProcess = cbToWrite;
2737
2738
2739	out:
2740	LogFlowFunc(("returns %Rrc\n", rc));
2741	return rc;
2742	}
2743
2744	static int qcowAsyncFlush(void *pBackendData, PVDIOCTX pIoCtx)
2745	{
2746	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2747	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2748	int rc = VINF_SUCCESS;
2749
2750	Assert(pImage);
2751
2752	if (VALID_PTR(pIoCtx))
2753	rc = qcowFlushImageAsync(pImage, pIoCtx);
2754	else
2755	rc = VERR_INVALID_PARAMETER;
2756
2757	LogFlowFunc(("returns %Rrc\n", rc));
2758	return rc;
2759	}
2760
2761	VBOXHDDBACKEND g_QCowBackend =
2762	{
2763	/* pszBackendName */
2764	"QCOW",
2765	/* cbSize */
2766	sizeof(VBOXHDDBACKEND),
2767	/* uBackendCaps */
2768	VD_CAP_FILE \| VD_CAP_VFS \| VD_CAP_CREATE_DYNAMIC \| VD_CAP_DIFF \| VD_CAP_ASYNC,
2769	/* paFileExtensions */
2770	s_aQCowFileExtensions,
2771	/* paConfigInfo */
2772	NULL,
2773	/* hPlugin */
2774	NIL_RTLDRMOD,
2775	/* pfnCheckIfValid */
2776	qcowCheckIfValid,
2777	/* pfnOpen */
2778	qcowOpen,
2779	/* pfnCreate */
2780	qcowCreate,
2781	/* pfnRename */
2782	qcowRename,
2783	/* pfnClose */
2784	qcowClose,
2785	/* pfnRead */
2786	qcowRead,
2787	/* pfnWrite */
2788	qcowWrite,
2789	/* pfnFlush */
2790	qcowFlush,
2791	/* pfnGetVersion */
2792	qcowGetVersion,
2793	/* pfnGetSize */
2794	qcowGetSize,
2795	/* pfnGetFileSize */
2796	qcowGetFileSize,
2797	/* pfnGetPCHSGeometry */
2798	qcowGetPCHSGeometry,
2799	/* pfnSetPCHSGeometry */
2800	qcowSetPCHSGeometry,
2801	/* pfnGetLCHSGeometry */
2802	qcowGetLCHSGeometry,
2803	/* pfnSetLCHSGeometry */
2804	qcowSetLCHSGeometry,
2805	/* pfnGetImageFlags */
2806	qcowGetImageFlags,
2807	/* pfnGetOpenFlags */
2808	qcowGetOpenFlags,
2809	/* pfnSetOpenFlags */
2810	qcowSetOpenFlags,
2811	/* pfnGetComment */
2812	qcowGetComment,
2813	/* pfnSetComment */
2814	qcowSetComment,
2815	/* pfnGetUuid */
2816	qcowGetUuid,
2817	/* pfnSetUuid */
2818	qcowSetUuid,
2819	/* pfnGetModificationUuid */
2820	qcowGetModificationUuid,
2821	/* pfnSetModificationUuid */
2822	qcowSetModificationUuid,
2823	/* pfnGetParentUuid */
2824	qcowGetParentUuid,
2825	/* pfnSetParentUuid */
2826	qcowSetParentUuid,
2827	/* pfnGetParentModificationUuid */
2828	qcowGetParentModificationUuid,
2829	/* pfnSetParentModificationUuid */
2830	qcowSetParentModificationUuid,
2831	/* pfnDump */
2832	qcowDump,
2833	/* pfnGetTimeStamp */
2834	NULL,
2835	/* pfnGetParentTimeStamp */
2836	NULL,
2837	/* pfnSetParentTimeStamp */
2838	NULL,
2839	/* pfnGetParentFilename */
2840	qcowGetParentFilename,
2841	/* pfnSetParentFilename */
2842	qcowSetParentFilename,
2843	/* pfnAsyncRead */
2844	qcowAsyncRead,
2845	/* pfnAsyncWrite */
2846	qcowAsyncWrite,
2847	/* pfnAsyncFlush */
2848	qcowAsyncFlush,
2849	/* pfnComposeLocation */
2850	genericFileComposeLocation,
2851	/* pfnComposeName */
2852	genericFileComposeName,
2853	/* pfnCompact */
2854	NULL,
2855	/* pfnResize */
2856	NULL,
2857	/* pfnDiscard */
2858	NULL,
2859	/* pfnAsyncDiscard */
2860	NULL,
2861	/* pfnRepair */
2862	NULL
2863	};

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source: vbox/trunk/src/VBox/Storage/QCOW.cpp@ 44232

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