QCOW.cpp@ 76985

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1	/* $Id: QCOW.cpp 76553 2019-01-01 01:45:53Z vboxsync $ */
2	/** @file
3	* QCOW - QCOW Disk image.
4	*/
5
6	/*
7	* Copyright (C) 2011-2019 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	/*********************************************************************************************************************************
20	* Header Files *
21	*********************************************************************************************************************************/
22	#define LOG_GROUP LOG_GROUP_VD_QCOW
23	#include <VBox/vd-plugin.h>
24	#include <VBox/err.h>
25
26	#include <VBox/log.h>
27	#include <iprt/asm.h>
28	#include <iprt/assert.h>
29	#include <iprt/string.h>
30	#include <iprt/alloc.h>
31	#include <iprt/path.h>
32	#include <iprt/list.h>
33
34	#include "VDBackends.h"
35	#include "VDBackendsInline.h"
36
37	/** @page pg_storage_qcow QCOW Storage Backend
38	* The QCOW backend implements support for the qemu copy on write format (short QCOW).
39	* There is no official specification available but the format is described
40	* at http://people.gnome.org/~markmc/qcow-image-format.html for version 2
41	* and http://people.gnome.org/~markmc/qcow-image-format-version-1.html for version 1.
42	*
43	* Missing things to implement:
44	* - v2 image creation and handling of the reference count table. (Blocker to enable support for V2 images)
45	* - cluster encryption
46	* - cluster compression
47	* - compaction
48	* - resizing
49	*/
50
51
52	/*********************************************************************************************************************************
53	* Structures in a QCOW image, big endian *
54	*********************************************************************************************************************************/
55
56	#pragma pack(1) /* Completely unnecessary. */
57	typedef struct QCowHeader
58	{
59	/** Magic value. */
60	uint32_t u32Magic;
61	/** Version of the image. */
62	uint32_t u32Version;
63	/** Version dependent data. */
64	union
65	{
66	/** Version 1. */
67	struct
68	{
69	/** Backing file offset. */
70	uint64_t u64BackingFileOffset;
71	/** Size of the backing file. */
72	uint32_t u32BackingFileSize;
73	/** mtime (Modification time?) - can be ignored. */
74	uint32_t u32MTime;
75	/** Logical size of the image in bytes. */
76	uint64_t u64Size;
77	/** Number of bits in the virtual offset used as a cluster offset. */
78	uint8_t u8ClusterBits;
79	/** Number of bits in the virtual offset used for the L2 index. */
80	uint8_t u8L2Bits;
81	/** Padding because the header is not packed in the original source. */
82	uint16_t u16Padding;
83	/** Used cryptographic method. */
84	uint32_t u32CryptMethod;
85	/** Offset of the L1 table in the image in bytes. */
86	uint64_t u64L1TableOffset;
87	} v1;
88	/** Version 2. */
89	struct
90	{
91	/** Backing file offset. */
92	uint64_t u64BackingFileOffset;
93	/** Size of the backing file. */
94	uint32_t u32BackingFileSize;
95	/** Number of bits in the virtual offset used as a cluster offset. */
96	uint32_t u32ClusterBits;
97	/** Logical size of the image. */
98	uint64_t u64Size;
99	/** Used cryptographic method. */
100	uint32_t u32CryptMethod;
101	/** Size of the L1 table in entries (each 8bytes big). */
102	uint32_t u32L1Size;
103	/** Offset of the L1 table in the image in bytes. */
104	uint64_t u64L1TableOffset;
105	/** Start of the refcount table in the image. */
106	uint64_t u64RefcountTableOffset;
107	/** Size of the refcount table in clusters. */
108	uint32_t u32RefcountTableClusters;
109	/** Number of snapshots in the image. */
110	uint32_t u32NbSnapshots;
111	/** Offset of the first snapshot header in the image. */
112	uint64_t u64SnapshotsOffset;
113	} v2;
114	} Version;
115	} QCowHeader;
116	#pragma pack()
117	/** Pointer to a on disk QCOW header. */
118	typedef QCowHeader *PQCowHeader;
119
120	/** QCOW magic value. */
121	#define QCOW_MAGIC UINT32_C(0x514649fb) /* QFI\0xfb */
122	/** Size of the V1 header. */
123	#define QCOW_V1_HDR_SIZE (48)
124	/** Size of the V2 header. */
125	#define QCOW_V2_HDR_SIZE (72)
126
127	/** Cluster is compressed flag for QCOW images. */
128	#define QCOW_V1_COMPRESSED_FLAG RT_BIT_64(63)
129
130	/** Copied flag for QCOW2 images. */
131	#define QCOW_V2_COPIED_FLAG RT_BIT_64(63)
132	/** Cluster is compressed flag for QCOW2 images. */
133	#define QCOW_V2_COMPRESSED_FLAG RT_BIT_64(62)
134
135
136	/*********************************************************************************************************************************
137	* Constants And Macros, Structures and Typedefs *
138	*********************************************************************************************************************************/
139
140	/**
141	* QCOW L2 cache entry.
142	*/
143	typedef struct QCOWL2CACHEENTRY
144	{
145	/** List node for the search list. */
146	RTLISTNODE NodeSearch;
147	/** List node for the LRU list. */
148	RTLISTNODE NodeLru;
149	/** Reference counter. */
150	uint32_t cRefs;
151	/** The offset of the L2 table, used as search key. */
152	uint64_t offL2Tbl;
153	/** Pointer to the cached L2 table. */
154	uint64_t *paL2Tbl;
155	} QCOWL2CACHEENTRY, *PQCOWL2CACHEENTRY;
156
157	/** Maximum amount of memory the cache is allowed to use. */
158	#define QCOW_L2_CACHE_MEMORY_MAX (2*_1M)
159
160	/** QCOW default cluster size for image version 2. */
161	#define QCOW2_CLUSTER_SIZE_DEFAULT (64*_1K)
162	/** QCOW default cluster size for image version 1. */
163	#define QCOW_CLUSTER_SIZE_DEFAULT (4*_1K)
164	/** QCOW default L2 table size in clusters. */
165	#define QCOW_L2_CLUSTERS_DEFAULT (1)
166
167	/**
168	* QCOW image data structure.
169	*/
170	typedef struct QCOWIMAGE
171	{
172	/** Image name. */
173	const char *pszFilename;
174	/** Storage handle. */
175	PVDIOSTORAGE pStorage;
176
177	/** Pointer to the per-disk VD interface list. */
178	PVDINTERFACE pVDIfsDisk;
179	/** Pointer to the per-image VD interface list. */
180	PVDINTERFACE pVDIfsImage;
181	/** Error interface. */
182	PVDINTERFACEERROR pIfError;
183	/** I/O interface. */
184	PVDINTERFACEIOINT pIfIo;
185
186	/** Open flags passed by VBoxHD layer. */
187	unsigned uOpenFlags;
188	/** Image flags defined during creation or determined during open. */
189	unsigned uImageFlags;
190	/** Total size of the image. */
191	uint64_t cbSize;
192	/** Physical geometry of this image. */
193	VDGEOMETRY PCHSGeometry;
194	/** Logical geometry of this image. */
195	VDGEOMETRY LCHSGeometry;
196
197	/** Image version. */
198	unsigned uVersion;
199	/** MTime field - used only to preserve value in opened images, unmodified otherwise. */
200	uint32_t MTime;
201
202	/** Filename of the backing file if any. */
203	char *pszBackingFilename;
204	/** Offset of the filename in the image. */
205	uint64_t offBackingFilename;
206	/** Size of the backing filename excluding \0. */
207	uint32_t cbBackingFilename;
208
209	/** Next offset of a new cluster, aligned to sector size. */
210	uint64_t offNextCluster;
211	/** Cluster size in bytes. */
212	uint32_t cbCluster;
213	/** Number of entries in the L1 table. */
214	uint32_t cL1TableEntries;
215	/** Size of an L1 rounded to the next cluster size. */
216	uint32_t cbL1Table;
217	/** Pointer to the L1 table. */
218	uint64_t *paL1Table;
219	/** Offset of the L1 table. */
220	uint64_t offL1Table;
221
222	/** Size of the L2 table in bytes. */
223	uint32_t cbL2Table;
224	/** Number of entries in the L2 table. */
225	uint32_t cL2TableEntries;
226	/** Memory occupied by the L2 table cache. */
227	size_t cbL2Cache;
228	/** The sorted L2 entry list used for searching. */
229	RTLISTNODE ListSearch;
230	/** The LRU L2 entry list used for eviction. */
231	RTLISTNODE ListLru;
232
233	/** Offset of the refcount table. */
234	uint64_t offRefcountTable;
235	/** Size of the refcount table in bytes. */
236	uint32_t cbRefcountTable;
237	/** Number of entries in the refcount table. */
238	uint32_t cRefcountTableEntries;
239	/** Pointer to the refcount table. */
240	uint64_t *paRefcountTable;
241
242	/** Offset mask for a cluster. */
243	uint64_t fOffsetMask;
244	/** Number of bits to shift to get the L1 index. */
245	uint32_t cL1Shift;
246	/** L2 table mask to get the L2 index. */
247	uint64_t fL2Mask;
248	/** Number of bits to shift to get the L2 index. */
249	uint32_t cL2Shift;
250
251	/** Pointer to the L2 table we are currently allocating
252	* (can be only one at a time). */
253	PQCOWL2CACHEENTRY pL2TblAlloc;
254	/** The static region list. */
255	VDREGIONLIST RegionList;
256	} QCOWIMAGE, *PQCOWIMAGE;
257
258	/**
259	* State of the async cluster allocation.
260	*/
261	typedef enum QCOWCLUSTERASYNCALLOCSTATE
262	{
263	/** Invalid. */
264	QCOWCLUSTERASYNCALLOCSTATE_INVALID = 0,
265	/** L2 table allocation. */
266	QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC,
267	/** Link L2 table into L1. */
268	QCOWCLUSTERASYNCALLOCSTATE_L2_LINK,
269	/** Allocate user data cluster. */
270	QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC,
271	/** Link user data cluster. */
272	QCOWCLUSTERASYNCALLOCSTATE_USER_LINK,
273	/** 32bit blowup. */
274	QCOWCLUSTERASYNCALLOCSTATE_32BIT_HACK = 0x7fffffff
275	} QCOWCLUSTERASYNCALLOCSTATE, *PQCOWCLUSTERASYNCALLOCSTATE;
276
277	/**
278	* Data needed to track async cluster allocation.
279	*/
280	typedef struct QCOWCLUSTERASYNCALLOC
281	{
282	/** The state of the cluster allocation. */
283	QCOWCLUSTERASYNCALLOCSTATE enmAllocState;
284	/** Old image size to rollback in case of an error. */
285	uint64_t offNextClusterOld;
286	/** L1 index to link if any. */
287	uint32_t idxL1;
288	/** L2 index to link, required in any case. */
289	uint32_t idxL2;
290	/** Start offset of the allocated cluster. */
291	uint64_t offClusterNew;
292	/** L2 cache entry if a L2 table is allocated. */
293	PQCOWL2CACHEENTRY pL2Entry;
294	/** Number of bytes to write. */
295	size_t cbToWrite;
296	} QCOWCLUSTERASYNCALLOC, *PQCOWCLUSTERASYNCALLOC;
297
298
299	/*********************************************************************************************************************************
300	* Static Variables *
301	*********************************************************************************************************************************/
302
303	/** NULL-terminated array of supported file extensions. */
304	static const VDFILEEXTENSION s_aQCowFileExtensions[] =
305	{
306	{"qcow", VDTYPE_HDD},
307	{"qcow2", VDTYPE_HDD},
308	{NULL, VDTYPE_INVALID}
309	};
310
311
312	/*********************************************************************************************************************************
313	* Internal Functions *
314	*********************************************************************************************************************************/
315
316	/**
317	* Return power of 2 or 0 if num error.
318	*
319	* @returns The power of 2 or 0 if the given number is not a power of 2.
320	* @param u32 The number.
321	*/
322	static uint32_t qcowGetPowerOfTwo(uint32_t u32)
323	{
324	if (u32 == 0)
325	return 0;
326	uint32_t uPower2 = 0;
327	while ((u32 & 1) == 0)
328	{
329	u32 >>= 1;
330	uPower2++;
331	}
332	return u32 == 1 ? uPower2 : 0;
333	}
334
335
336	/**
337	* Converts the image header to the host endianess and performs basic checks.
338	*
339	* @returns Whether the given header is valid or not.
340	* @param pHeader Pointer to the header to convert.
341	*/
342	static bool qcowHdrConvertToHostEndianess(PQCowHeader pHeader)
343	{
344	pHeader->u32Magic = RT_BE2H_U32(pHeader->u32Magic);
345	pHeader->u32Version = RT_BE2H_U32(pHeader->u32Version);
346
347	if (pHeader->u32Magic != QCOW_MAGIC)
348	return false;
349
350	if (pHeader->u32Version == 1)
351	{
352	pHeader->Version.v1.u64BackingFileOffset = RT_BE2H_U64(pHeader->Version.v1.u64BackingFileOffset);
353	pHeader->Version.v1.u32BackingFileSize = RT_BE2H_U32(pHeader->Version.v1.u32BackingFileSize);
354	pHeader->Version.v1.u32MTime = RT_BE2H_U32(pHeader->Version.v1.u32MTime);
355	pHeader->Version.v1.u64Size = RT_BE2H_U64(pHeader->Version.v1.u64Size);
356	pHeader->Version.v1.u32CryptMethod = RT_BE2H_U32(pHeader->Version.v1.u32CryptMethod);
357	pHeader->Version.v1.u64L1TableOffset = RT_BE2H_U64(pHeader->Version.v1.u64L1TableOffset);
358	}
359	else if (pHeader->u32Version == 2)
360	{
361	pHeader->Version.v2.u64BackingFileOffset = RT_BE2H_U64(pHeader->Version.v2.u64BackingFileOffset);
362	pHeader->Version.v2.u32BackingFileSize = RT_BE2H_U32(pHeader->Version.v2.u32BackingFileSize);
363	pHeader->Version.v2.u32ClusterBits = RT_BE2H_U32(pHeader->Version.v2.u32ClusterBits);
364	pHeader->Version.v2.u64Size = RT_BE2H_U64(pHeader->Version.v2.u64Size);
365	pHeader->Version.v2.u32CryptMethod = RT_BE2H_U32(pHeader->Version.v2.u32CryptMethod);
366	pHeader->Version.v2.u32L1Size = RT_BE2H_U32(pHeader->Version.v2.u32L1Size);
367	pHeader->Version.v2.u64L1TableOffset = RT_BE2H_U64(pHeader->Version.v2.u64L1TableOffset);
368	pHeader->Version.v2.u64RefcountTableOffset = RT_BE2H_U64(pHeader->Version.v2.u64RefcountTableOffset);
369	pHeader->Version.v2.u32RefcountTableClusters = RT_BE2H_U32(pHeader->Version.v2.u32RefcountTableClusters);
370	pHeader->Version.v2.u32NbSnapshots = RT_BE2H_U32(pHeader->Version.v2.u32NbSnapshots);
371	pHeader->Version.v2.u64SnapshotsOffset = RT_BE2H_U64(pHeader->Version.v2.u64SnapshotsOffset);
372	}
373	else
374	return false;
375
376	return true;
377	}
378
379	/**
380	* Creates a QCOW header from the given image state.
381	*
382	* @returns nothing.
383	* @param pImage Image instance data.
384	* @param pHeader Pointer to the header to convert.
385	* @param pcbHeader Where to store the size of the header to write.
386	*/
387	static void qcowHdrConvertFromHostEndianess(PQCOWIMAGE pImage, PQCowHeader pHeader,
388	size_t *pcbHeader)
389	{
390	memset(pHeader, 0, sizeof(QCowHeader));
391
392	pHeader->u32Magic = RT_H2BE_U32(QCOW_MAGIC);
393	pHeader->u32Version = RT_H2BE_U32(pImage->uVersion);
394	if (pImage->uVersion == 1)
395	{
396	pHeader->Version.v1.u64BackingFileOffset = RT_H2BE_U64(pImage->offBackingFilename);
397	pHeader->Version.v1.u32BackingFileSize = RT_H2BE_U32(pImage->cbBackingFilename);
398	pHeader->Version.v1.u32MTime = RT_H2BE_U32(pImage->MTime);
399	pHeader->Version.v1.u64Size = RT_H2BE_U64(pImage->cbSize);
400	pHeader->Version.v1.u8ClusterBits = (uint8_t)qcowGetPowerOfTwo(pImage->cbCluster);
401	pHeader->Version.v1.u8L2Bits = (uint8_t)qcowGetPowerOfTwo(pImage->cL2TableEntries);
402	pHeader->Version.v1.u32CryptMethod = RT_H2BE_U32(0);
403	pHeader->Version.v1.u64L1TableOffset = RT_H2BE_U64(pImage->offL1Table);
404	*pcbHeader = QCOW_V1_HDR_SIZE;
405	}
406	else if (pImage->uVersion == 2)
407	{
408	pHeader->Version.v2.u64BackingFileOffset = RT_H2BE_U64(pImage->offBackingFilename);
409	pHeader->Version.v2.u32BackingFileSize = RT_H2BE_U32(pImage->cbBackingFilename);
410	pHeader->Version.v2.u32ClusterBits = RT_H2BE_U32(qcowGetPowerOfTwo(pImage->cbCluster));
411	pHeader->Version.v2.u64Size = RT_H2BE_U64(pImage->cbSize);
412	pHeader->Version.v2.u32CryptMethod = RT_H2BE_U32(0);
413	pHeader->Version.v2.u32L1Size = RT_H2BE_U32(pImage->cL1TableEntries);
414	pHeader->Version.v2.u64L1TableOffset = RT_H2BE_U64(pImage->offL1Table);
415	pHeader->Version.v2.u64RefcountTableOffset = RT_H2BE_U64(pImage->offRefcountTable);
416	pHeader->Version.v2.u32RefcountTableClusters = RT_H2BE_U32(pImage->cbRefcountTable / pImage->cbCluster);
417	pHeader->Version.v2.u32NbSnapshots = RT_H2BE_U32(0);
418	pHeader->Version.v2.u64SnapshotsOffset = RT_H2BE_U64((uint64_t)0);
419	*pcbHeader = QCOW_V2_HDR_SIZE;
420	}
421	else
422	AssertMsgFailed(("Invalid version of the QCOW image format %d\n", pImage->uVersion));
423	}
424
425	/**
426	* Convert table entries from little endian to host endianess.
427	*
428	* @returns nothing.
429	* @param paTbl Pointer to the table.
430	* @param cEntries Number of entries in the table.
431	*/
432	static void qcowTableConvertToHostEndianess(uint64_t *paTbl, uint32_t cEntries)
433	{
434	while(cEntries-- > 0)
435	{
436	paTbl = RT_BE2H_U64(paTbl);
437	paTbl++;
438	}
439	}
440
441	/**
442	* Convert table entries from host to little endian format.
443	*
444	* @returns nothing.
445	* @param paTblImg Pointer to the table which will store the little endian table.
446	* @param paTbl The source table to convert.
447	* @param cEntries Number of entries in the table.
448	*/
449	static void qcowTableConvertFromHostEndianess(uint64_t paTblImg, uint64_t paTbl,
450	uint32_t cEntries)
451	{
452	while(cEntries-- > 0)
453	{
454	paTblImg = RT_H2BE_U64(paTbl);
455	paTbl++;
456	paTblImg++;
457	}
458	}
459
460	/**
461	* Creates the L2 table cache.
462	*
463	* @returns VBox status code.
464	* @param pImage The image instance data.
465	*/
466	static int qcowL2TblCacheCreate(PQCOWIMAGE pImage)
467	{
468	pImage->cbL2Cache = 0;
469	RTListInit(&pImage->ListSearch);
470	RTListInit(&pImage->ListLru);
471
472	return VINF_SUCCESS;
473	}
474
475	/**
476	* Destroys the L2 table cache.
477	*
478	* @returns nothing.
479	* @param pImage The image instance data.
480	*/
481	static void qcowL2TblCacheDestroy(PQCOWIMAGE pImage)
482	{
483	PQCOWL2CACHEENTRY pL2Entry;
484	PQCOWL2CACHEENTRY pL2Next;
485	RTListForEachSafe(&pImage->ListSearch, pL2Entry, pL2Next, QCOWL2CACHEENTRY, NodeSearch)
486	{
487	Assert(!pL2Entry->cRefs);
488
489	RTListNodeRemove(&pL2Entry->NodeSearch);
490	RTMemPageFree(pL2Entry->paL2Tbl, pImage->cbL2Table);
491	RTMemFree(pL2Entry);
492	}
493
494	pImage->cbL2Cache = 0;
495	RTListInit(&pImage->ListSearch);
496	RTListInit(&pImage->ListLru);
497	}
498
499	/**
500	* Returns the L2 table matching the given offset or NULL if none could be found.
501	*
502	* @returns Pointer to the L2 table cache entry or NULL.
503	* @param pImage The image instance data.
504	* @param offL2Tbl Offset of the L2 table to search for.
505	*/
506	static PQCOWL2CACHEENTRY qcowL2TblCacheRetain(PQCOWIMAGE pImage, uint64_t offL2Tbl)
507	{
508	if ( pImage->pL2TblAlloc
509	&& pImage->pL2TblAlloc->offL2Tbl == offL2Tbl)
510	{
511	pImage->pL2TblAlloc->cRefs++;
512	return pImage->pL2TblAlloc;
513	}
514
515	PQCOWL2CACHEENTRY pL2Entry;
516	RTListForEach(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch)
517	{
518	if (pL2Entry->offL2Tbl == offL2Tbl)
519	break;
520	}
521
522	if (!RTListNodeIsDummy(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch))
523	{
524	/* Update LRU list. */
525	RTListNodeRemove(&pL2Entry->NodeLru);
526	RTListPrepend(&pImage->ListLru, &pL2Entry->NodeLru);
527	pL2Entry->cRefs++;
528	return pL2Entry;
529	}
530
531	return NULL;
532	}
533
534	/**
535	* Releases a L2 table cache entry.
536	*
537	* @returns nothing.
538	* @param pL2Entry The L2 cache entry.
539	*/
540	static void qcowL2TblCacheEntryRelease(PQCOWL2CACHEENTRY pL2Entry)
541	{
542	Assert(pL2Entry->cRefs > 0);
543	pL2Entry->cRefs--;
544	}
545
546	/**
547	* Allocates a new L2 table from the cache evicting old entries if required.
548	*
549	* @returns Pointer to the L2 cache entry or NULL.
550	* @param pImage The image instance data.
551	*/
552	static PQCOWL2CACHEENTRY qcowL2TblCacheEntryAlloc(PQCOWIMAGE pImage)
553	{
554	PQCOWL2CACHEENTRY pL2Entry = NULL;
555
556	if (pImage->cbL2Cache + pImage->cbL2Table <= QCOW_L2_CACHE_MEMORY_MAX)
557	{
558	/* Add a new entry. */
559	pL2Entry = (PQCOWL2CACHEENTRY)RTMemAllocZ(sizeof(QCOWL2CACHEENTRY));
560	if (pL2Entry)
561	{
562	pL2Entry->paL2Tbl = (uint64_t *)RTMemPageAllocZ(pImage->cbL2Table);
563	if (RT_UNLIKELY(!pL2Entry->paL2Tbl))
564	{
565	RTMemFree(pL2Entry);
566	pL2Entry = NULL;
567	}
568	else
569	{
570	pL2Entry->cRefs = 1;
571	pImage->cbL2Cache += pImage->cbL2Table;
572	}
573	}
574	}
575	else
576	{
577	/* Evict the last not in use entry and use it */
578	Assert(!RTListIsEmpty(&pImage->ListLru));
579
580	RTListForEachReverse(&pImage->ListLru, pL2Entry, QCOWL2CACHEENTRY, NodeLru)
581	{
582	if (!pL2Entry->cRefs)
583	break;
584	}
585
586	if (!RTListNodeIsDummy(&pImage->ListSearch, pL2Entry, QCOWL2CACHEENTRY, NodeSearch))
587	{
588	RTListNodeRemove(&pL2Entry->NodeSearch);
589	RTListNodeRemove(&pL2Entry->NodeLru);
590	pL2Entry->offL2Tbl = 0;
591	pL2Entry->cRefs = 1;
592	}
593	else
594	pL2Entry = NULL;
595	}
596
597	return pL2Entry;
598	}
599
600	/**
601	* Frees a L2 table cache entry.
602	*
603	* @returns nothing.
604	* @param pImage The image instance data.
605	* @param pL2Entry The L2 cache entry to free.
606	*/
607	static void qcowL2TblCacheEntryFree(PQCOWIMAGE pImage, PQCOWL2CACHEENTRY pL2Entry)
608	{
609	Assert(!pL2Entry->cRefs);
610	RTMemPageFree(pL2Entry->paL2Tbl, pImage->cbL2Table);
611	RTMemFree(pL2Entry);
612
613	pImage->cbL2Cache -= pImage->cbL2Table;
614	}
615
616	/**
617	* Inserts an entry in the L2 table cache.
618	*
619	* @returns nothing.
620	* @param pImage The image instance data.
621	* @param pL2Entry The L2 cache entry to insert.
622	*/
623	static void qcowL2TblCacheEntryInsert(PQCOWIMAGE pImage, PQCOWL2CACHEENTRY pL2Entry)
624	{
625	Assert(pL2Entry->offL2Tbl > 0);
626
627	/* Insert at the top of the LRU list. */
628	RTListPrepend(&pImage->ListLru, &pL2Entry->NodeLru);
629
630	if (RTListIsEmpty(&pImage->ListSearch))
631	{
632	RTListAppend(&pImage->ListSearch, &pL2Entry->NodeSearch);
633	}
634	else
635	{
636	/* Insert into search list. */
637	PQCOWL2CACHEENTRY pIt;
638	pIt = RTListGetFirst(&pImage->ListSearch, QCOWL2CACHEENTRY, NodeSearch);
639	if (pIt->offL2Tbl > pL2Entry->offL2Tbl)
640	RTListPrepend(&pImage->ListSearch, &pL2Entry->NodeSearch);
641	else
642	{
643	bool fInserted = false;
644
645	RTListForEach(&pImage->ListSearch, pIt, QCOWL2CACHEENTRY, NodeSearch)
646	{
647	Assert(pIt->offL2Tbl != pL2Entry->offL2Tbl);
648	if (pIt->offL2Tbl < pL2Entry->offL2Tbl)
649	{
650	RTListNodeInsertAfter(&pIt->NodeSearch, &pL2Entry->NodeSearch);
651	fInserted = true;
652	break;
653	}
654	}
655	Assert(fInserted);
656	}
657	}
658	}
659
660	/**
661	* Fetches the L2 from the given offset trying the LRU cache first and
662	* reading it from the image after a cache miss.
663	*
664	* @returns VBox status code.
665	* @param pImage Image instance data.
666	* @param pIoCtx The I/O context.
667	* @param offL2Tbl The offset of the L2 table in the image.
668	* @param ppL2Entry Where to store the L2 table on success.
669	*/
670	static int qcowL2TblCacheFetch(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, uint64_t offL2Tbl,
671	PQCOWL2CACHEENTRY *ppL2Entry)
672	{
673	int rc = VINF_SUCCESS;
674
675	/* Try to fetch the L2 table from the cache first. */
676	PQCOWL2CACHEENTRY pL2Entry = qcowL2TblCacheRetain(pImage, offL2Tbl);
677	if (!pL2Entry)
678	{
679	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
680
681	if (pL2Entry)
682	{
683	/* Read from the image. */
684	PVDMETAXFER pMetaXfer;
685
686	pL2Entry->offL2Tbl = offL2Tbl;
687	rc = vdIfIoIntFileReadMeta(pImage->pIfIo, pImage->pStorage,
688	offL2Tbl, pL2Entry->paL2Tbl,
689	pImage->cbL2Table, pIoCtx,
690	&pMetaXfer, NULL, NULL);
691	if (RT_SUCCESS(rc))
692	{
693	vdIfIoIntMetaXferRelease(pImage->pIfIo, pMetaXfer);
694	#if defined(RT_LITTLE_ENDIAN)
695	qcowTableConvertToHostEndianess(pL2Entry->paL2Tbl, pImage->cL2TableEntries);
696	#endif
697	qcowL2TblCacheEntryInsert(pImage, pL2Entry);
698	}
699	else
700	{
701	qcowL2TblCacheEntryRelease(pL2Entry);
702	qcowL2TblCacheEntryFree(pImage, pL2Entry);
703	}
704	}
705	else
706	rc = VERR_NO_MEMORY;
707	}
708
709	if (RT_SUCCESS(rc))
710	*ppL2Entry = pL2Entry;
711
712	return rc;
713	}
714
715	/**
716	* Sets the L1, L2 and offset bitmasks and L1 and L2 bit shift members.
717	*
718	* @returns nothing.
719	* @param pImage The image instance data.
720	*/
721	static void qcowTableMasksInit(PQCOWIMAGE pImage)
722	{
723	uint32_t cClusterBits, cL2TableBits;
724
725	cClusterBits = qcowGetPowerOfTwo(pImage->cbCluster);
726	cL2TableBits = qcowGetPowerOfTwo(pImage->cL2TableEntries);
727
728	Assert(cClusterBits + cL2TableBits < 64);
729
730	pImage->fOffsetMask = ((uint64_t)pImage->cbCluster - 1);
731	pImage->fL2Mask = ((uint64_t)pImage->cL2TableEntries - 1) << cClusterBits;
732	pImage->cL2Shift = cClusterBits;
733	pImage->cL1Shift = cClusterBits + cL2TableBits;
734	}
735
736	/**
737	* Converts a given logical offset into the
738	*
739	* @returns nothing.
740	* @param pImage The image instance data.
741	* @param off The logical offset to convert.
742	* @param pidxL1 Where to store the index in the L1 table on success.
743	* @param pidxL2 Where to store the index in the L2 table on success.
744	* @param poffCluster Where to store the offset in the cluster on success.
745	*/
746	DECLINLINE(void) qcowConvertLogicalOffset(PQCOWIMAGE pImage, uint64_t off, uint32_t *pidxL1,
747	uint32_t pidxL2, uint32_t poffCluster)
748	{
749	AssertPtr(pidxL1);
750	AssertPtr(pidxL2);
751	AssertPtr(poffCluster);
752
753	*poffCluster = off & pImage->fOffsetMask;
754	*pidxL1 = off >> pImage->cL1Shift;
755	*pidxL2 = (off & pImage->fL2Mask) >> pImage->cL2Shift;
756	}
757
758	/**
759	* Converts Cluster size to a byte size.
760	*
761	* @returns Number of bytes derived from the given number of clusters.
762	* @param pImage The image instance data.
763	* @param cClusters The clusters to convert.
764	*/
765	DECLINLINE(uint64_t) qcowCluster2Byte(PQCOWIMAGE pImage, uint64_t cClusters)
766	{
767	return cClusters * pImage->cbCluster;
768	}
769
770	/**
771	* Converts number of bytes to cluster size rounding to the next cluster.
772	*
773	* @returns Number of bytes derived from the given number of clusters.
774	* @param pImage The image instance data.
775	* @param cb Number of bytes to convert.
776	*/
777	DECLINLINE(uint64_t) qcowByte2Cluster(PQCOWIMAGE pImage, uint64_t cb)
778	{
779	return cb / pImage->cbCluster + (cb % pImage->cbCluster ? 1 : 0);
780	}
781
782	/**
783	* Allocates a new cluster in the image.
784	*
785	* @returns The start offset of the new cluster in the image.
786	* @param pImage The image instance data.
787	* @param cClusters Number of clusters to allocate.
788	*/
789	DECLINLINE(uint64_t) qcowClusterAllocate(PQCOWIMAGE pImage, uint32_t cClusters)
790	{
791	uint64_t offCluster;
792
793	offCluster = pImage->offNextCluster;
794	pImage->offNextCluster += cClusters*pImage->cbCluster;
795
796	return offCluster;
797	}
798
799	/**
800	* Returns the real image offset for a given cluster or an error if the cluster is not
801	* yet allocated.
802	*
803	* @returns VBox status code.
804	* VERR_VD_BLOCK_FREE if the cluster is not yet allocated.
805	* @param pImage The image instance data.
806	* @param pIoCtx The I/O context.
807	* @param idxL1 The L1 index.
808	* @param idxL2 The L2 index.
809	* @param offCluster Offset inside the cluster.
810	* @param poffImage Where to store the image offset on success;
811	*/
812	static int qcowConvertToImageOffset(PQCOWIMAGE pImage, PVDIOCTX pIoCtx,
813	uint32_t idxL1, uint32_t idxL2,
814	uint32_t offCluster, uint64_t *poffImage)
815	{
816	int rc = VERR_VD_BLOCK_FREE;
817
818	AssertReturn(idxL1 < pImage->cL1TableEntries, VERR_INVALID_PARAMETER);
819	AssertReturn(idxL2 < pImage->cL2TableEntries, VERR_INVALID_PARAMETER);
820
821	if (pImage->paL1Table[idxL1])
822	{
823	PQCOWL2CACHEENTRY pL2Entry;
824
825	rc = qcowL2TblCacheFetch(pImage, pIoCtx, pImage->paL1Table[idxL1], &pL2Entry);
826	if (RT_SUCCESS(rc))
827	{
828	/* Get real file offset. */
829	if (pL2Entry->paL2Tbl[idxL2])
830	{
831	uint64_t off = pL2Entry->paL2Tbl[idxL2];
832
833	/* Strip flags */
834	if (pImage->uVersion == 2)
835	{
836	if (RT_UNLIKELY(off & QCOW_V2_COMPRESSED_FLAG))
837	rc = VERR_NOT_SUPPORTED;
838	else
839	off &= ~(QCOW_V2_COMPRESSED_FLAG \| QCOW_V2_COPIED_FLAG);
840	}
841	else
842	{
843	if (RT_UNLIKELY(off & QCOW_V1_COMPRESSED_FLAG))
844	rc = VERR_NOT_SUPPORTED;
845	else
846	off &= ~QCOW_V1_COMPRESSED_FLAG;
847	}
848
849	*poffImage = off + offCluster;
850	}
851	else
852	rc = VERR_VD_BLOCK_FREE;
853
854	qcowL2TblCacheEntryRelease(pL2Entry);
855	}
856	}
857
858	return rc;
859	}
860
861	/**
862	* Write the given table to image converting to the image endianess if required.
863	*
864	* @returns VBox status code.
865	* @param pImage The image instance data.
866	* @param pIoCtx The I/O context.
867	* @param offTbl The offset the table should be written to.
868	* @param paTbl The table to write.
869	* @param cbTbl Size of the table in bytes.
870	* @param cTblEntries Number entries in the table.
871	* @param pfnComplete Callback called when the write completes.
872	* @param pvUser Opaque user data to pass in the completion callback.
873	*/
874	static int qcowTblWrite(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, uint64_t offTbl, uint64_t *paTbl,
875	size_t cbTbl, unsigned cTblEntries,
876	PFNVDXFERCOMPLETED pfnComplete, void *pvUser)
877	{
878	int rc = VINF_SUCCESS;
879
880	#if defined(RT_LITTLE_ENDIAN)
881	uint64_t paTblImg = (uint64_t )RTMemAllocZ(cbTbl);
882	if (paTblImg)
883	{
884	qcowTableConvertFromHostEndianess(paTblImg, paTbl, cTblEntries);
885	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
886	offTbl, paTblImg, cbTbl,
887	pIoCtx, pfnComplete, pvUser);
888	RTMemFree(paTblImg);
889	}
890	else
891	rc = VERR_NO_MEMORY;
892	#else
893	/* Write table directly. */
894	RT_NOREF(cTblEntries);
895	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
896	offTbl, paTbl, cbTbl, pIoCtx,
897	pfnComplete, pvUser);
898	#endif
899
900	return rc;
901	}
902
903	/**
904	* Internal. Flush image data to disk.
905	*/
906	static int qcowFlushImage(PQCOWIMAGE pImage)
907	{
908	int rc = VINF_SUCCESS;
909
910	if ( pImage->pStorage
911	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
912	&& pImage->cbL1Table)
913	{
914	QCowHeader Header;
915
916	#if defined(RT_LITTLE_ENDIAN)
917	uint64_t paL1TblImg = (uint64_t )RTMemAllocZ(pImage->cbL1Table);
918	if (paL1TblImg)
919	{
920	qcowTableConvertFromHostEndianess(paL1TblImg, pImage->paL1Table,
921	pImage->cL1TableEntries);
922	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
923	pImage->offL1Table, paL1TblImg,
924	pImage->cbL1Table);
925	RTMemFree(paL1TblImg);
926	}
927	else
928	rc = VERR_NO_MEMORY;
929	#else
930	/* Write L1 table directly. */
931	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, pImage->offL1Table,
932	pImage->paL1Table, pImage->cbL1Table);
933	#endif
934	if (RT_SUCCESS(rc))
935	{
936	/* Write header. */
937	size_t cbHeader = 0;
938	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
939	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, 0, &Header,
940	cbHeader);
941	if (RT_SUCCESS(rc))
942	rc = vdIfIoIntFileFlushSync(pImage->pIfIo, pImage->pStorage);
943	}
944	}
945
946	return rc;
947	}
948
949	/**
950	* Internal. Free all allocated space for representing an image except pImage,
951	* and optionally delete the image from disk.
952	*/
953	static int qcowFreeImage(PQCOWIMAGE pImage, bool fDelete)
954	{
955	int rc = VINF_SUCCESS;
956
957	/* Freeing a never allocated image (e.g. because the open failed) is
958	* not signalled as an error. After all nothing bad happens. */
959	if (pImage)
960	{
961	if (pImage->pStorage)
962	{
963	/* No point updating the file that is deleted anyway. */
964	if (!fDelete)
965	qcowFlushImage(pImage);
966
967	rc = vdIfIoIntFileClose(pImage->pIfIo, pImage->pStorage);
968	pImage->pStorage = NULL;
969	}
970
971	if (pImage->paL1Table)
972	RTMemFree(pImage->paL1Table);
973
974	if (pImage->pszBackingFilename)
975	{
976	RTMemFree(pImage->pszBackingFilename);
977	pImage->pszBackingFilename = NULL;
978	}
979
980	qcowL2TblCacheDestroy(pImage);
981
982	if (fDelete && pImage->pszFilename)
983	vdIfIoIntFileDelete(pImage->pIfIo, pImage->pszFilename);
984	}
985
986	LogFlowFunc(("returns %Rrc\n", rc));
987	return rc;
988	}
989
990	/**
991	* Validates the header.
992	*
993	* @returns VBox status code.
994	* @param pImage Image backend instance data.
995	* @param pHdr The header to validate.
996	* @param cbFile The image file size in bytes.
997	*/
998	static int qcowHdrValidate(PQCOWIMAGE pImage, PQCowHeader pHdr, uint64_t cbFile)
999	{
1000	if (pHdr->u32Version == 1)
1001	{
1002	/* Check that the backing filename is contained in the file. */
1003	if (pHdr->Version.v1.u64BackingFileOffset + pHdr->Version.v1.u32BackingFileSize > cbFile)
1004	return vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1005	N_("QCOW: Backing file offset and size exceed size of image '%s' (%u vs %u)"),
1006	pImage->pszFilename, pHdr->Version.v1.u64BackingFileOffset + pHdr->Version.v1.u32BackingFileSize,
1007	cbFile);
1008
1009	/* Check that the cluster bits indicate at least a 512byte sector size. */
1010	if (RT_BIT_32(pHdr->Version.v1.u8ClusterBits) < 512)
1011	return vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1012	N_("QCOW: Cluster size is too small for image '%s' (%u vs %u)"),
1013	pImage->pszFilename, RT_BIT_32(pHdr->Version.v1.u8ClusterBits), 512);
1014
1015	/*
1016	* Check for possible overflow when multiplying cluster size and L2 entry count because it is used
1017	* to calculate the number of L1 table entries later on.
1018	*/
1019	if (RT_BIT_32(pHdr->Version.v1.u8L2Bits) * RT_BIT_32(pHdr->Version.v1.u8ClusterBits) == 0)
1020	return vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1021	N_("QCOW: Overflow during L1 table size calculation for image '%s'"),
1022	pImage->pszFilename);
1023	}
1024	else if (pHdr->u32Version == 2)
1025	{
1026	/* Check that the backing filename is contained in the file. */
1027	if (pHdr->Version.v2.u64BackingFileOffset + pHdr->Version.v2.u32BackingFileSize > cbFile)
1028	return vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1029	N_("QCOW: Backing file offset and size exceed size of image '%s' (%u vs %u)"),
1030	pImage->pszFilename, pHdr->Version.v2.u64BackingFileOffset + pHdr->Version.v2.u32BackingFileSize,
1031	cbFile);
1032
1033	/* Check that the cluster bits indicate at least a 512byte sector size. */
1034	if (RT_BIT_32(pHdr->Version.v2.u32ClusterBits) < 512)
1035	return vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1036	N_("QCOW: Cluster size is too small for image '%s' (%u vs %u)"),
1037	pImage->pszFilename, RT_BIT_32(pHdr->Version.v2.u32ClusterBits), 512);
1038	}
1039	else
1040	return vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1041	N_("QCOW: Version %u in image '%s' is not supported"),
1042	pHdr->u32Version, pImage->pszFilename);
1043
1044	return VINF_SUCCESS;
1045	}
1046
1047	/**
1048	* Internal: Open an image, constructing all necessary data structures.
1049	*/
1050	static int qcowOpenImage(PQCOWIMAGE pImage, unsigned uOpenFlags)
1051	{
1052	pImage->uOpenFlags = uOpenFlags;
1053
1054	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1055	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1056	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1057
1058	int rc = qcowL2TblCacheCreate(pImage);
1059	if (RT_SUCCESS(rc))
1060	{
1061	/* Open the image. */
1062	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename,
1063	VDOpenFlagsToFileOpenFlags(uOpenFlags,
1064	false /* fCreate */),
1065	&pImage->pStorage);
1066	if (RT_SUCCESS(rc))
1067	{
1068	uint64_t cbFile;
1069	rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
1070	if ( RT_SUCCESS(rc)
1071	&& cbFile > sizeof(QCowHeader))
1072	{
1073	QCowHeader Header;
1074
1075	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage, 0, &Header, sizeof(Header));
1076	if ( RT_SUCCESS(rc)
1077	&& qcowHdrConvertToHostEndianess(&Header))
1078	{
1079	pImage->offNextCluster = RT_ALIGN_64(cbFile, 512); /* Align image to sector boundary. */
1080	Assert(pImage->offNextCluster >= cbFile);
1081
1082	rc = qcowHdrValidate(pImage, &Header, cbFile);
1083	if (RT_SUCCESS(rc))
1084	{
1085	if (Header.u32Version == 1)
1086	{
1087	if (!Header.Version.v1.u32CryptMethod)
1088	{
1089	pImage->uVersion = 1;
1090	pImage->offBackingFilename = Header.Version.v1.u64BackingFileOffset;
1091	pImage->cbBackingFilename = Header.Version.v1.u32BackingFileSize;
1092	pImage->MTime = Header.Version.v1.u32MTime;
1093	pImage->cbSize = Header.Version.v1.u64Size;
1094	pImage->cbCluster = RT_BIT_32(Header.Version.v1.u8ClusterBits);
1095	pImage->cL2TableEntries = RT_BIT_32(Header.Version.v1.u8L2Bits);
1096	pImage->cbL2Table = RT_ALIGN_64(pImage->cL2TableEntries * sizeof(uint64_t), pImage->cbCluster);
1097	pImage->offL1Table = Header.Version.v1.u64L1TableOffset;
1098	pImage->cL1TableEntries = pImage->cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1099	if (pImage->cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1100	pImage->cL1TableEntries++;
1101	}
1102	else
1103	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1104	N_("QCow: Encrypted image '%s' is not supported"),
1105	pImage->pszFilename);
1106	}
1107	else if (Header.u32Version == 2)
1108	{
1109	if (Header.Version.v2.u32CryptMethod)
1110	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1111	N_("QCow: Encrypted image '%s' is not supported"),
1112	pImage->pszFilename);
1113	else if (Header.Version.v2.u32NbSnapshots)
1114	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1115	N_("QCow: Image '%s' contains snapshots which is not supported"),
1116	pImage->pszFilename);
1117	else
1118	{
1119	pImage->uVersion = 2;
1120	pImage->offBackingFilename = Header.Version.v2.u64BackingFileOffset;
1121	pImage->cbBackingFilename = Header.Version.v2.u32BackingFileSize;
1122	pImage->cbSize = Header.Version.v2.u64Size;
1123	pImage->cbCluster = RT_BIT_32(Header.Version.v2.u32ClusterBits);
1124	pImage->cL2TableEntries = pImage->cbCluster / sizeof(uint64_t);
1125	pImage->cbL2Table = pImage->cbCluster;
1126	pImage->offL1Table = Header.Version.v2.u64L1TableOffset;
1127	pImage->cL1TableEntries = Header.Version.v2.u32L1Size;
1128	pImage->offRefcountTable = Header.Version.v2.u64RefcountTableOffset;
1129	pImage->cbRefcountTable = qcowCluster2Byte(pImage, Header.Version.v2.u32RefcountTableClusters);
1130	pImage->cRefcountTableEntries = pImage->cbRefcountTable / sizeof(uint64_t);
1131	}
1132	}
1133	else
1134	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1135	N_("QCow: Image '%s' uses version %u which is not supported"),
1136	pImage->pszFilename, Header.u32Version);
1137
1138	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1139	if ((uint64_t)pImage->cbL1Table != RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster))
1140	rc = vdIfError(pImage->pIfError, VERR_INVALID_STATE, RT_SRC_POS,
1141	N_("QCOW: L1 table size overflow in image '%s'"),
1142	pImage->pszFilename);
1143	}
1144
1145	/** @todo Check that there are no compressed clusters in the image
1146	* (by traversing the L2 tables and checking each offset).
1147	* Refuse to open such images.
1148	*/
1149
1150	if ( RT_SUCCESS(rc)
1151	&& pImage->cbBackingFilename
1152	&& pImage->offBackingFilename)
1153	{
1154	/* Load backing filename from image. */
1155	pImage->pszBackingFilename = (char )RTMemAllocZ(pImage->cbBackingFilename + 1); / +1 for \0 terminator. */
1156	if (pImage->pszBackingFilename)
1157	{
1158	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1159	pImage->offBackingFilename, pImage->pszBackingFilename,
1160	pImage->cbBackingFilename);
1161	}
1162	else
1163	rc = VERR_NO_MEMORY;
1164	}
1165
1166	if ( RT_SUCCESS(rc)
1167	&& pImage->cbRefcountTable
1168	&& pImage->offRefcountTable)
1169	{
1170	/* Load refcount table. */
1171	Assert(pImage->cRefcountTableEntries);
1172	pImage->paRefcountTable = (uint64_t *)RTMemAllocZ(pImage->cbRefcountTable);
1173	if (RT_LIKELY(pImage->paRefcountTable))
1174	{
1175	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1176	pImage->offRefcountTable, pImage->paRefcountTable,
1177	pImage->cbRefcountTable);
1178	if (RT_SUCCESS(rc))
1179	qcowTableConvertToHostEndianess(pImage->paRefcountTable,
1180	pImage->cRefcountTableEntries);
1181	else
1182	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1183	N_("QCow: Reading refcount table of image '%s' failed"),
1184	pImage->pszFilename);
1185	}
1186	else
1187	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1188	N_("QCow: Allocating memory for refcount table of image '%s' failed"),
1189	pImage->pszFilename);
1190	}
1191
1192	if (RT_SUCCESS(rc))
1193	{
1194	qcowTableMasksInit(pImage);
1195
1196	/* Allocate L1 table. */
1197	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1198	if (pImage->paL1Table)
1199	{
1200	/* Read from the image. */
1201	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1202	pImage->offL1Table, pImage->paL1Table,
1203	pImage->cbL1Table);
1204	if (RT_SUCCESS(rc))
1205	qcowTableConvertToHostEndianess(pImage->paL1Table, pImage->cL1TableEntries);
1206	else
1207	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1208	N_("QCow: Reading the L1 table for image '%s' failed"),
1209	pImage->pszFilename);
1210	}
1211	else
1212	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1213	N_("QCow: Out of memory allocating L1 table for image '%s'"),
1214	pImage->pszFilename);
1215	}
1216	}
1217	else if (RT_SUCCESS(rc))
1218	rc = VERR_VD_GEN_INVALID_HEADER;
1219	}
1220	else if (RT_SUCCESS(rc))
1221	rc = VERR_VD_GEN_INVALID_HEADER;
1222	}
1223	/* else: Do NOT signal an appropriate error here, as the VD layer has the
1224	* choice of retrying the open if it failed. */
1225	}
1226	else
1227	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1228	N_("Qcow: Creating the L2 table cache for image '%s' failed"),
1229	pImage->pszFilename);
1230
1231	if (RT_SUCCESS(rc))
1232	{
1233	PVDREGIONDESC pRegion = &pImage->RegionList.aRegions[0];
1234	pImage->RegionList.fFlags = 0;
1235	pImage->RegionList.cRegions = 1;
1236
1237	pRegion->offRegion = 0; /* Disk start. */
1238	pRegion->cbBlock = 512;
1239	pRegion->enmDataForm = VDREGIONDATAFORM_RAW;
1240	pRegion->enmMetadataForm = VDREGIONMETADATAFORM_NONE;
1241	pRegion->cbData = 512;
1242	pRegion->cbMetadata = 0;
1243	pRegion->cRegionBlocksOrBytes = pImage->cbSize;
1244	}
1245	else
1246	qcowFreeImage(pImage, false);
1247	return rc;
1248	}
1249
1250	/**
1251	* Internal: Create a qcow image.
1252	*/
1253	static int qcowCreateImage(PQCOWIMAGE pImage, uint64_t cbSize,
1254	unsigned uImageFlags, const char *pszComment,
1255	PCVDGEOMETRY pPCHSGeometry,
1256	PCVDGEOMETRY pLCHSGeometry, unsigned uOpenFlags,
1257	PVDINTERFACEPROGRESS pIfProgress,
1258	unsigned uPercentStart, unsigned uPercentSpan)
1259	{
1260	RT_NOREF1(pszComment);
1261	int rc;
1262	int32_t fOpen;
1263
1264	if (!(uImageFlags & VD_IMAGE_FLAGS_FIXED))
1265	{
1266	rc = qcowL2TblCacheCreate(pImage);
1267	if (RT_SUCCESS(rc))
1268	{
1269	pImage->uOpenFlags = uOpenFlags & ~VD_OPEN_FLAGS_READONLY;
1270	pImage->uImageFlags = uImageFlags;
1271	pImage->PCHSGeometry = *pPCHSGeometry;
1272	pImage->LCHSGeometry = *pLCHSGeometry;
1273	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1274	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1275	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1276
1277	/* Create image file. */
1278	fOpen = VDOpenFlagsToFileOpenFlags(pImage->uOpenFlags, true /* fCreate */);
1279	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename, fOpen, &pImage->pStorage);
1280	if (RT_SUCCESS(rc))
1281	{
1282	/* Init image state. */
1283	pImage->uVersion = 1; /* We create only version 1 images at the moment. */
1284	pImage->cbSize = cbSize;
1285	pImage->cbCluster = QCOW_CLUSTER_SIZE_DEFAULT;
1286	pImage->cbL2Table = qcowCluster2Byte(pImage, QCOW_L2_CLUSTERS_DEFAULT);
1287	pImage->cL2TableEntries = pImage->cbL2Table / sizeof(uint64_t);
1288	pImage->cL1TableEntries = cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1289	if (cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1290	pImage->cL1TableEntries++;
1291	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1292	pImage->offL1Table = QCOW_V1_HDR_SIZE;
1293	pImage->cbBackingFilename = 0;
1294	pImage->offBackingFilename = 0;
1295	pImage->offNextCluster = RT_ALIGN_64(QCOW_V1_HDR_SIZE + pImage->cbL1Table, pImage->cbCluster);
1296	qcowTableMasksInit(pImage);
1297
1298	/* Init L1 table. */
1299	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1300	if (RT_LIKELY(pImage->paL1Table))
1301	{
1302	if (RT_SUCCESS(rc))
1303	vdIfProgress(pIfProgress, uPercentStart + uPercentSpan * 98 / 100);
1304
1305	rc = qcowFlushImage(pImage);
1306	if (RT_SUCCESS(rc))
1307	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pImage->offNextCluster);
1308	}
1309	else
1310	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS, N_("QCow: cannot allocate memory for L1 table of image '%s'"),
1311	pImage->pszFilename);
1312	}
1313	else
1314	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: cannot create image '%s'"), pImage->pszFilename);
1315	}
1316	else
1317	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: Failed to create L2 cache for image '%s'"),
1318	pImage->pszFilename);
1319	}
1320	else
1321	rc = vdIfError(pImage->pIfError, VERR_VD_INVALID_TYPE, RT_SRC_POS, N_("QCow: cannot create fixed image '%s'"), pImage->pszFilename);
1322
1323	if (RT_SUCCESS(rc))
1324	vdIfProgress(pIfProgress, uPercentStart + uPercentSpan);
1325
1326	if (RT_SUCCESS(rc))
1327	{
1328	PVDREGIONDESC pRegion = &pImage->RegionList.aRegions[0];
1329	pImage->RegionList.fFlags = 0;
1330	pImage->RegionList.cRegions = 1;
1331
1332	pRegion->offRegion = 0; /* Disk start. */
1333	pRegion->cbBlock = 512;
1334	pRegion->enmDataForm = VDREGIONDATAFORM_RAW;
1335	pRegion->enmMetadataForm = VDREGIONMETADATAFORM_NONE;
1336	pRegion->cbData = 512;
1337	pRegion->cbMetadata = 0;
1338	pRegion->cRegionBlocksOrBytes = pImage->cbSize;
1339	}
1340	else
1341	qcowFreeImage(pImage, rc != VERR_ALREADY_EXISTS);
1342	return rc;
1343	}
1344
1345	/**
1346	* Rollback anything done during async cluster allocation.
1347	*
1348	* @returns VBox status code.
1349	* @param pImage The image instance data.
1350	* @param pIoCtx The I/O context.
1351	* @param pClusterAlloc The cluster allocation to rollback.
1352	*/
1353	static int qcowAsyncClusterAllocRollback(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, PQCOWCLUSTERASYNCALLOC pClusterAlloc)
1354	{
1355	RT_NOREF1(pIoCtx);
1356	int rc = VINF_SUCCESS;
1357
1358	switch (pClusterAlloc->enmAllocState)
1359	{
1360	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1361	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1362	{
1363	/* Revert the L1 table entry */
1364	pImage->paL1Table[pClusterAlloc->idxL1] = 0;
1365	pImage->pL2TblAlloc = NULL;
1366
1367	/* Assumption right now is that the L1 table is not modified on storage if the link fails. */
1368	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1369	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1370	Assert(!pClusterAlloc->pL2Entry->cRefs);
1371	qcowL2TblCacheEntryFree(pImage, pClusterAlloc->pL2Entry); /* Free it, it is not in the cache yet. */
1372	break;
1373	}
1374	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1375	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1376	{
1377	/* Assumption right now is that the L2 table is not modified if the link fails. */
1378	pClusterAlloc->pL2Entry->paL2Tbl[pClusterAlloc->idxL2] = 0;
1379	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1380	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1381	break;
1382	}
1383	default:
1384	AssertMsgFailed(("Invalid cluster allocation state %d\n", pClusterAlloc->enmAllocState));
1385	rc = VERR_INVALID_STATE;
1386	}
1387
1388	RTMemFree(pClusterAlloc);
1389	return rc;
1390	}
1391
1392	/**
1393	* Updates the state of the async cluster allocation.
1394	*
1395	* @returns VBox status code.
1396	* @param pBackendData The opaque backend data.
1397	* @param pIoCtx I/O context associated with this request.
1398	* @param pvUser Opaque user data passed during a read/write request.
1399	* @param rcReq Status code for the completed request.
1400	*/
1401	static DECLCALLBACK(int) qcowAsyncClusterAllocUpdate(void pBackendData, PVDIOCTX pIoCtx, void pvUser, int rcReq)
1402	{
1403	int rc = VINF_SUCCESS;
1404	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1405	PQCOWCLUSTERASYNCALLOC pClusterAlloc = (PQCOWCLUSTERASYNCALLOC)pvUser;
1406
1407	if (RT_FAILURE(rcReq))
1408	return qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1409
1410	AssertPtr(pClusterAlloc->pL2Entry);
1411
1412	switch (pClusterAlloc->enmAllocState)
1413	{
1414	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1415	{
1416	/* Update the link in the in memory L1 table now. */
1417	pImage->paL1Table[pClusterAlloc->idxL1] = pClusterAlloc->pL2Entry->offL2Tbl;
1418
1419	/* Update the link in the on disk L1 table now. */
1420	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_LINK;
1421	rc = qcowTblWrite(pImage, pIoCtx, pImage->offL1Table, pImage->paL1Table,
1422	pImage->cbL1Table, pImage->cL1TableEntries,
1423	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1424	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1425	break;
1426	else if (RT_FAILURE(rc))
1427	{
1428	/* Rollback. */
1429	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1430	break;
1431	}
1432	/* Success, fall through. */
1433	}
1434	RT_FALL_THRU();
1435	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1436	{
1437	/* L2 link updated in L1 , save L2 entry in cache and allocate new user data cluster. */
1438	uint64_t offData = qcowClusterAllocate(pImage, 1);
1439
1440	pImage->pL2TblAlloc = NULL;
1441	qcowL2TblCacheEntryInsert(pImage, pClusterAlloc->pL2Entry);
1442
1443	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
1444	pClusterAlloc->offNextClusterOld = offData;
1445	pClusterAlloc->offClusterNew = offData;
1446
1447	/* Write data. */
1448	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1449	offData, pIoCtx, pClusterAlloc->cbToWrite,
1450	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1451	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1452	break;
1453	else if (RT_FAILURE(rc))
1454	{
1455	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1456	RTMemFree(pClusterAlloc);
1457	break;
1458	}
1459	}
1460	RT_FALL_THRU();
1461	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1462	{
1463	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_LINK;
1464	pClusterAlloc->pL2Entry->paL2Tbl[pClusterAlloc->idxL2] = pClusterAlloc->offClusterNew;
1465
1466	/* Link L2 table and update it. */
1467	rc = qcowTblWrite(pImage, pIoCtx, pImage->paL1Table[pClusterAlloc->idxL1],
1468	pClusterAlloc->pL2Entry->paL2Tbl,
1469	pImage->cbL2Table, pImage->cL2TableEntries,
1470	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1471	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1472	break;
1473	else if (RT_FAILURE(rc))
1474	{
1475	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1476	RTMemFree(pClusterAlloc);
1477	break;
1478	}
1479	}
1480	RT_FALL_THRU();
1481	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1482	{
1483	/* Everything done without errors, signal completion. */
1484	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry);
1485	RTMemFree(pClusterAlloc);
1486	rc = VINF_SUCCESS;
1487	break;
1488	}
1489	default:
1490	AssertMsgFailed(("Invalid async cluster allocation state %d\n",
1491	pClusterAlloc->enmAllocState));
1492	}
1493
1494	return rc;
1495	}
1496
1497	/** @copydoc VDIMAGEBACKEND::pfnProbe */
1498	static DECLCALLBACK(int) qcowProbe(const char *pszFilename, PVDINTERFACE pVDIfsDisk,
1499	PVDINTERFACE pVDIfsImage, VDTYPE *penmType)
1500	{
1501	RT_NOREF1(pVDIfsDisk);
1502	LogFlowFunc(("pszFilename=\"%s\" pVDIfsDisk=%#p pVDIfsImage=%#p\n", pszFilename, pVDIfsDisk, pVDIfsImage));
1503	PVDIOSTORAGE pStorage = NULL;
1504	uint64_t cbFile;
1505	int rc = VINF_SUCCESS;
1506
1507	/* Get I/O interface. */
1508	PVDINTERFACEIOINT pIfIo = VDIfIoIntGet(pVDIfsImage);
1509	AssertPtrReturn(pIfIo, VERR_INVALID_PARAMETER);
1510	AssertReturn((VALID_PTR(pszFilename) && *pszFilename), VERR_INVALID_PARAMETER);
1511
1512	/*
1513	* Open the file and read the footer.
1514	*/
1515	rc = vdIfIoIntFileOpen(pIfIo, pszFilename,
1516	VDOpenFlagsToFileOpenFlags(VD_OPEN_FLAGS_READONLY,
1517	false /* fCreate */),
1518	&pStorage);
1519	if (RT_SUCCESS(rc))
1520	{
1521	rc = vdIfIoIntFileGetSize(pIfIo, pStorage, &cbFile);
1522	if ( RT_SUCCESS(rc)
1523	&& cbFile > sizeof(QCowHeader))
1524	{
1525	QCowHeader Header;
1526
1527	rc = vdIfIoIntFileReadSync(pIfIo, pStorage, 0, &Header, sizeof(Header));
1528	if ( RT_SUCCESS(rc)
1529	&& qcowHdrConvertToHostEndianess(&Header))
1530	*penmType = VDTYPE_HDD;
1531	else
1532	rc = VERR_VD_GEN_INVALID_HEADER;
1533	}
1534	else
1535	rc = VERR_VD_GEN_INVALID_HEADER;
1536	}
1537
1538	if (pStorage)
1539	vdIfIoIntFileClose(pIfIo, pStorage);
1540
1541	LogFlowFunc(("returns %Rrc\n", rc));
1542	return rc;
1543	}
1544
1545	/** @copydoc VDIMAGEBACKEND::pfnOpen */
1546	static DECLCALLBACK(int) qcowOpen(const char *pszFilename, unsigned uOpenFlags,
1547	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1548	VDTYPE enmType, void **ppBackendData)
1549	{
1550	RT_NOREF1(enmType); /*< @todo r=klaus make use of the type info. /
1551
1552	LogFlowFunc(("pszFilename=\"%s\" uOpenFlags=%#x pVDIfsDisk=%#p pVDIfsImage=%#p enmType=%u ppBackendData=%#p\n",
1553	pszFilename, uOpenFlags, pVDIfsDisk, pVDIfsImage, enmType, ppBackendData));
1554	int rc;
1555
1556	/* Check open flags. All valid flags are supported. */
1557	AssertReturn(!(uOpenFlags & ~VD_OPEN_FLAGS_MASK), VERR_INVALID_PARAMETER);
1558	AssertReturn((VALID_PTR(pszFilename) && *pszFilename), VERR_INVALID_PARAMETER);
1559
1560	PQCOWIMAGE pImage = (PQCOWIMAGE)RTMemAllocZ(RT_UOFFSETOF(QCOWIMAGE, RegionList.aRegions[1]));
1561	if (RT_LIKELY(pImage))
1562	{
1563	pImage->pszFilename = pszFilename;
1564	pImage->pStorage = NULL;
1565	pImage->pVDIfsDisk = pVDIfsDisk;
1566	pImage->pVDIfsImage = pVDIfsImage;
1567
1568	rc = qcowOpenImage(pImage, uOpenFlags);
1569	if (RT_SUCCESS(rc))
1570	*ppBackendData = pImage;
1571	else
1572	RTMemFree(pImage);
1573	}
1574	else
1575	rc = VERR_NO_MEMORY;
1576
1577	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1578	return rc;
1579	}
1580
1581	/** @copydoc VDIMAGEBACKEND::pfnCreate */
1582	static DECLCALLBACK(int) qcowCreate(const char *pszFilename, uint64_t cbSize,
1583	unsigned uImageFlags, const char *pszComment,
1584	PCVDGEOMETRY pPCHSGeometry, PCVDGEOMETRY pLCHSGeometry,
1585	PCRTUUID pUuid, unsigned uOpenFlags,
1586	unsigned uPercentStart, unsigned uPercentSpan,
1587	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1588	PVDINTERFACE pVDIfsOperation, VDTYPE enmType,
1589	void **ppBackendData)
1590	{
1591	RT_NOREF1(pUuid);
1592	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 enmType=%u ppBackendData=%#p\n",
1593	pszFilename, cbSize, uImageFlags, pszComment, pPCHSGeometry, pLCHSGeometry, pUuid, uOpenFlags, uPercentStart, uPercentSpan, pVDIfsDisk, pVDIfsImage, pVDIfsOperation, enmType, ppBackendData));
1594	int rc;
1595
1596	/* Check the VD container type. */
1597	if (enmType != VDTYPE_HDD)
1598	return VERR_VD_INVALID_TYPE;
1599
1600	/* Check open flags. All valid flags are supported. */
1601	AssertReturn(!(uOpenFlags & ~VD_OPEN_FLAGS_MASK), VERR_INVALID_PARAMETER);
1602	AssertReturn( VALID_PTR(pszFilename)
1603	&& *pszFilename
1604	&& VALID_PTR(pPCHSGeometry)
1605	&& VALID_PTR(pLCHSGeometry), VERR_INVALID_PARAMETER);
1606
1607	PQCOWIMAGE pImage = (PQCOWIMAGE)RTMemAllocZ(RT_UOFFSETOF(QCOWIMAGE, RegionList.aRegions[1]));
1608	if (RT_LIKELY(pImage))
1609	{
1610	PVDINTERFACEPROGRESS pIfProgress = VDIfProgressGet(pVDIfsOperation);
1611
1612	pImage->pszFilename = pszFilename;
1613	pImage->pStorage = NULL;
1614	pImage->pVDIfsDisk = pVDIfsDisk;
1615	pImage->pVDIfsImage = pVDIfsImage;
1616
1617	rc = qcowCreateImage(pImage, cbSize, uImageFlags, pszComment,
1618	pPCHSGeometry, pLCHSGeometry, uOpenFlags,
1619	pIfProgress, uPercentStart, uPercentSpan);
1620	if (RT_SUCCESS(rc))
1621	{
1622	/* So far the image is opened in read/write mode. Make sure the
1623	* image is opened in read-only mode if the caller requested that. */
1624	if (uOpenFlags & VD_OPEN_FLAGS_READONLY)
1625	{
1626	qcowFreeImage(pImage, false);
1627	rc = qcowOpenImage(pImage, uOpenFlags);
1628	}
1629
1630	if (RT_SUCCESS(rc))
1631	*ppBackendData = pImage;
1632	}
1633
1634	if (RT_FAILURE(rc))
1635	RTMemFree(pImage);
1636	}
1637	else
1638	rc = VERR_NO_MEMORY;
1639
1640	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1641	return rc;
1642	}
1643
1644	/** @copydoc VDIMAGEBACKEND::pfnRename */
1645	static DECLCALLBACK(int) qcowRename(void pBackendData, const char pszFilename)
1646	{
1647	LogFlowFunc(("pBackendData=%#p pszFilename=%#p\n", pBackendData, pszFilename));
1648	int rc = VINF_SUCCESS;
1649	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1650
1651	/* Check arguments. */
1652	AssertReturn((pImage && pszFilename && *pszFilename), VERR_INVALID_PARAMETER);
1653
1654	/* Close the image. */
1655	rc = qcowFreeImage(pImage, false);
1656	if (RT_SUCCESS(rc))
1657	{
1658	/* Rename the file. */
1659	rc = vdIfIoIntFileMove(pImage->pIfIo, pImage->pszFilename, pszFilename, 0);
1660	if (RT_SUCCESS(rc))
1661	{
1662	/* Update pImage with the new information. */
1663	pImage->pszFilename = pszFilename;
1664
1665	/* Open the old image with new name. */
1666	rc = qcowOpenImage(pImage, pImage->uOpenFlags);
1667	}
1668	else
1669	{
1670	/* The move failed, try to reopen the original image. */
1671	int rc2 = qcowOpenImage(pImage, pImage->uOpenFlags);
1672	if (RT_FAILURE(rc2))
1673	rc = rc2;
1674	}
1675	}
1676
1677	LogFlowFunc(("returns %Rrc\n", rc));
1678	return rc;
1679	}
1680
1681	/** @copydoc VDIMAGEBACKEND::pfnClose */
1682	static DECLCALLBACK(int) qcowClose(void *pBackendData, bool fDelete)
1683	{
1684	LogFlowFunc(("pBackendData=%#p fDelete=%d\n", pBackendData, fDelete));
1685	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1686
1687	int rc = qcowFreeImage(pImage, fDelete);
1688	RTMemFree(pImage);
1689
1690	LogFlowFunc(("returns %Rrc\n", rc));
1691	return rc;
1692	}
1693
1694	static DECLCALLBACK(int) qcowRead(void *pBackendData, uint64_t uOffset, size_t cbToRead,
1695	PVDIOCTX pIoCtx, size_t *pcbActuallyRead)
1696	{
1697	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToRead=%zu pcbActuallyRead=%#p\n",
1698	pBackendData, uOffset, pIoCtx, cbToRead, pcbActuallyRead));
1699	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1700	uint32_t offCluster = 0;
1701	uint32_t idxL1 = 0;
1702	uint32_t idxL2 = 0;
1703	uint64_t offFile = 0;
1704	int rc;
1705
1706	AssertPtr(pImage);
1707	Assert(uOffset % 512 == 0);
1708	Assert(cbToRead % 512 == 0);
1709	AssertReturn((VALID_PTR(pIoCtx) && cbToRead), VERR_INVALID_PARAMETER);
1710	AssertReturn(uOffset + cbToRead <= pImage->cbSize, VERR_INVALID_PARAMETER);
1711
1712	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1713
1714	/* Clip read size to remain in the cluster. */
1715	cbToRead = RT_MIN(cbToRead, pImage->cbCluster - offCluster);
1716
1717	/* Get offset in image. */
1718	rc = qcowConvertToImageOffset(pImage, pIoCtx, idxL1, idxL2, offCluster, &offFile);
1719	if (RT_SUCCESS(rc))
1720	rc = vdIfIoIntFileReadUser(pImage->pIfIo, pImage->pStorage, offFile,
1721	pIoCtx, cbToRead);
1722
1723	if ( ( RT_SUCCESS(rc)
1724	\|\| rc == VERR_VD_BLOCK_FREE
1725	\|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1726	&& pcbActuallyRead)
1727	*pcbActuallyRead = cbToRead;
1728
1729	LogFlowFunc(("returns %Rrc\n", rc));
1730	return rc;
1731	}
1732
1733	static DECLCALLBACK(int) qcowWrite(void *pBackendData, uint64_t uOffset, size_t cbToWrite,
1734	PVDIOCTX pIoCtx, size_t pcbWriteProcess, size_t pcbPreRead,
1735	size_t *pcbPostRead, unsigned fWrite)
1736	{
1737	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToWrite=%zu pcbWriteProcess=%#p pcbPreRead=%#p pcbPostRead=%#p\n",
1738	pBackendData, uOffset, pIoCtx, cbToWrite, pcbWriteProcess, pcbPreRead, pcbPostRead));
1739	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1740	uint32_t offCluster = 0;
1741	uint32_t idxL1 = 0;
1742	uint32_t idxL2 = 0;
1743	uint64_t offImage = 0;
1744	int rc = VINF_SUCCESS;
1745
1746	AssertPtr(pImage);
1747	Assert(!(uOffset % 512));
1748	Assert(!(cbToWrite % 512));
1749	AssertReturn((VALID_PTR(pIoCtx) && cbToWrite), VERR_INVALID_PARAMETER);
1750	AssertReturn(uOffset + cbToWrite <= pImage->cbSize, VERR_INVALID_PARAMETER);
1751
1752	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
1753	{
1754	/* Convert offset to L1, L2 index and cluster offset. */
1755	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1756
1757	/* Clip write size to remain in the cluster. */
1758	cbToWrite = RT_MIN(cbToWrite, pImage->cbCluster - offCluster);
1759	Assert(!(cbToWrite % 512));
1760
1761	/* Get offset in image. */
1762	rc = qcowConvertToImageOffset(pImage, pIoCtx, idxL1, idxL2, offCluster, &offImage);
1763	if (RT_SUCCESS(rc))
1764	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1765	offImage, pIoCtx, cbToWrite, NULL, NULL);
1766	else if (rc == VERR_VD_BLOCK_FREE)
1767	{
1768	if ( cbToWrite == pImage->cbCluster
1769	&& !(fWrite & VD_WRITE_NO_ALLOC))
1770	{
1771	PQCOWL2CACHEENTRY pL2Entry = NULL;
1772
1773	/* Full cluster write to previously unallocated cluster.
1774	* Allocate cluster and write data. */
1775	Assert(!offCluster);
1776
1777	do
1778	{
1779	/* Check if we have to allocate a new cluster for L2 tables. */
1780	if (!pImage->paL1Table[idxL1])
1781	{
1782	uint64_t offL2Tbl;
1783	PQCOWCLUSTERASYNCALLOC pL2ClusterAlloc = NULL;
1784
1785	/* Allocate new async cluster allocation state. */
1786	pL2ClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
1787	if (RT_UNLIKELY(!pL2ClusterAlloc))
1788	{
1789	rc = VERR_NO_MEMORY;
1790	break;
1791	}
1792
1793	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
1794	if (!pL2Entry)
1795	{
1796	rc = VERR_NO_MEMORY;
1797	RTMemFree(pL2ClusterAlloc);
1798	break;
1799	}
1800
1801	offL2Tbl = qcowClusterAllocate(pImage, qcowByte2Cluster(pImage, pImage->cbL2Table));
1802	pL2Entry->offL2Tbl = offL2Tbl;
1803	memset(pL2Entry->paL2Tbl, 0, pImage->cbL2Table);
1804
1805	pL2ClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC;
1806	pL2ClusterAlloc->offNextClusterOld = offL2Tbl;
1807	pL2ClusterAlloc->offClusterNew = offL2Tbl;
1808	pL2ClusterAlloc->idxL1 = idxL1;
1809	pL2ClusterAlloc->idxL2 = idxL2;
1810	pL2ClusterAlloc->cbToWrite = cbToWrite;
1811	pL2ClusterAlloc->pL2Entry = pL2Entry;
1812
1813	pImage->pL2TblAlloc = pL2Entry;
1814
1815	LogFlowFunc(("Allocating new L2 table at cluster offset %llu\n", offL2Tbl));
1816
1817	/*
1818	* Write the L2 table first and link to the L1 table afterwards.
1819	* If something unexpected happens the worst case which can happen
1820	* is a leak of some clusters.
1821	*/
1822	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
1823	offL2Tbl, pL2Entry->paL2Tbl, pImage->cbL2Table, pIoCtx,
1824	qcowAsyncClusterAllocUpdate, pL2ClusterAlloc);
1825	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1826	break;
1827	else if (RT_FAILURE(rc))
1828	{
1829	RTMemFree(pL2ClusterAlloc);
1830	qcowL2TblCacheEntryFree(pImage, pL2Entry);
1831	break;
1832	}
1833
1834	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pL2ClusterAlloc, rc);
1835	}
1836	else
1837	{
1838	LogFlowFunc(("Fetching L2 table at cluster offset %llu\n", pImage->paL1Table[idxL1]));
1839
1840	rc = qcowL2TblCacheFetch(pImage, pIoCtx, pImage->paL1Table[idxL1],
1841	&pL2Entry);
1842	if (RT_SUCCESS(rc))
1843	{
1844	PQCOWCLUSTERASYNCALLOC pDataClusterAlloc = NULL;
1845
1846	/* Allocate new async cluster allocation state. */
1847	pDataClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
1848	if (RT_UNLIKELY(!pDataClusterAlloc))
1849	{
1850	rc = VERR_NO_MEMORY;
1851	break;
1852	}
1853
1854	/* Allocate new cluster for the data. */
1855	uint64_t offData = qcowClusterAllocate(pImage, 1);
1856
1857	pDataClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
1858	pDataClusterAlloc->offNextClusterOld = offData;
1859	pDataClusterAlloc->offClusterNew = offData;
1860	pDataClusterAlloc->idxL1 = idxL1;
1861	pDataClusterAlloc->idxL2 = idxL2;
1862	pDataClusterAlloc->cbToWrite = cbToWrite;
1863	pDataClusterAlloc->pL2Entry = pL2Entry;
1864
1865	/* Write data. */
1866	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1867	offData, pIoCtx, cbToWrite,
1868	qcowAsyncClusterAllocUpdate, pDataClusterAlloc);
1869	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1870	break;
1871	else if (RT_FAILURE(rc))
1872	{
1873	RTMemFree(pDataClusterAlloc);
1874	break;
1875	}
1876
1877	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pDataClusterAlloc, rc);
1878	}
1879	}
1880
1881	} while (0);
1882
1883	*pcbPreRead = 0;
1884	*pcbPostRead = 0;
1885	}
1886	else
1887	{
1888	/* Trying to do a partial write to an unallocated cluster. Don't do
1889	* anything except letting the upper layer know what to do. */
1890	*pcbPreRead = offCluster;
1891	pcbPostRead = pImage->cbCluster - cbToWrite - pcbPreRead;
1892	}
1893	}
1894
1895	if (pcbWriteProcess)
1896	*pcbWriteProcess = cbToWrite;
1897	}
1898	else
1899	rc = VERR_VD_IMAGE_READ_ONLY;
1900
1901	LogFlowFunc(("returns %Rrc\n", rc));
1902	return rc;
1903	}
1904
1905	static DECLCALLBACK(int) qcowFlush(void *pBackendData, PVDIOCTX pIoCtx)
1906	{
1907	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1908	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1909	int rc = VINF_SUCCESS;
1910
1911	AssertPtr(pImage);
1912	AssertPtrReturn(pIoCtx, VERR_INVALID_PARAMETER);
1913
1914	if ( pImage->pStorage
1915	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
1916	{
1917	QCowHeader Header;
1918
1919	rc = qcowTblWrite(pImage, pIoCtx, pImage->offL1Table, pImage->paL1Table,
1920	pImage->cbL1Table, pImage->cL1TableEntries, NULL, NULL);
1921	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1922	{
1923	/* Write header. */
1924	size_t cbHeader = 0;
1925	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
1926	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
1927	0, &Header, cbHeader,
1928	pIoCtx, NULL, NULL);
1929	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1930	rc = vdIfIoIntFileFlush(pImage->pIfIo, pImage->pStorage,
1931	pIoCtx, NULL, NULL);
1932	}
1933	}
1934
1935	LogFlowFunc(("returns %Rrc\n", rc));
1936	return rc;
1937	}
1938
1939	/** @copydoc VDIMAGEBACKEND::pfnGetVersion */
1940	static DECLCALLBACK(unsigned) qcowGetVersion(void *pBackendData)
1941	{
1942	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1943	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1944
1945	AssertPtrReturn(pImage, 0);
1946
1947	return pImage->uVersion;
1948	}
1949
1950	/** @copydoc VDIMAGEBACKEND::pfnGetFileSize */
1951	static DECLCALLBACK(uint64_t) qcowGetFileSize(void *pBackendData)
1952	{
1953	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1954	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1955	uint64_t cb = 0;
1956
1957	AssertPtrReturn(pImage, 0);
1958
1959	uint64_t cbFile;
1960	if (pImage->pStorage)
1961	{
1962	int rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
1963	if (RT_SUCCESS(rc))
1964	cb += cbFile;
1965	}
1966
1967	LogFlowFunc(("returns %lld\n", cb));
1968	return cb;
1969	}
1970
1971	/** @copydoc VDIMAGEBACKEND::pfnGetPCHSGeometry */
1972	static DECLCALLBACK(int) qcowGetPCHSGeometry(void *pBackendData, PVDGEOMETRY pPCHSGeometry)
1973	{
1974	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p\n", pBackendData, pPCHSGeometry));
1975	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1976	int rc = VINF_SUCCESS;
1977
1978	AssertPtrReturn(pImage, VERR_VD_NOT_OPENED);
1979
1980	if (pImage->PCHSGeometry.cCylinders)
1981	*pPCHSGeometry = pImage->PCHSGeometry;
1982	else
1983	rc = VERR_VD_GEOMETRY_NOT_SET;
1984
1985	LogFlowFunc(("returns %Rrc (PCHS=%u/%u/%u)\n", rc, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
1986	return rc;
1987	}
1988
1989	/** @copydoc VDIMAGEBACKEND::pfnSetPCHSGeometry */
1990	static DECLCALLBACK(int) qcowSetPCHSGeometry(void *pBackendData, PCVDGEOMETRY pPCHSGeometry)
1991	{
1992	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p PCHS=%u/%u/%u\n",
1993	pBackendData, pPCHSGeometry, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
1994	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1995	int rc = VINF_SUCCESS;
1996
1997	AssertPtrReturn(pImage, VERR_VD_NOT_OPENED);
1998
1999	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2000	rc = VERR_VD_IMAGE_READ_ONLY;
2001	else
2002	pImage->PCHSGeometry = *pPCHSGeometry;
2003
2004	LogFlowFunc(("returns %Rrc\n", rc));
2005	return rc;
2006	}
2007
2008	/** @copydoc VDIMAGEBACKEND::pfnGetLCHSGeometry */
2009	static DECLCALLBACK(int) qcowGetLCHSGeometry(void *pBackendData, PVDGEOMETRY pLCHSGeometry)
2010	{
2011	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p\n", pBackendData, pLCHSGeometry));
2012	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2013	int rc = VINF_SUCCESS;
2014
2015	AssertPtrReturn(pImage, VERR_VD_NOT_OPENED);
2016
2017	if (pImage->LCHSGeometry.cCylinders)
2018	*pLCHSGeometry = pImage->LCHSGeometry;
2019	else
2020	rc = VERR_VD_GEOMETRY_NOT_SET;
2021
2022	LogFlowFunc(("returns %Rrc (LCHS=%u/%u/%u)\n", rc, pLCHSGeometry->cCylinders,
2023	pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2024	return rc;
2025	}
2026
2027	/** @copydoc VDIMAGEBACKEND::pfnSetLCHSGeometry */
2028	static DECLCALLBACK(int) qcowSetLCHSGeometry(void *pBackendData, PCVDGEOMETRY pLCHSGeometry)
2029	{
2030	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p LCHS=%u/%u/%u\n", pBackendData,
2031	pLCHSGeometry, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2032	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2033	int rc = VINF_SUCCESS;
2034
2035	AssertPtrReturn(pImage, VERR_VD_NOT_OPENED);
2036
2037	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2038	rc = VERR_VD_IMAGE_READ_ONLY;
2039	else
2040	pImage->LCHSGeometry = *pLCHSGeometry;
2041
2042	LogFlowFunc(("returns %Rrc\n", rc));
2043	return rc;
2044	}
2045
2046	/** @copydoc VDIMAGEBACKEND::pfnQueryRegions */
2047	static DECLCALLBACK(int) qcowQueryRegions(void pBackendData, PCVDREGIONLIST ppRegionList)
2048	{
2049	LogFlowFunc(("pBackendData=%#p ppRegionList=%#p\n", pBackendData, ppRegionList));
2050	PQCOWIMAGE pThis = (PQCOWIMAGE)pBackendData;
2051
2052	AssertPtrReturn(pThis, VERR_VD_NOT_OPENED);
2053
2054	*ppRegionList = &pThis->RegionList;
2055	LogFlowFunc(("returns %Rrc\n", VINF_SUCCESS));
2056	return VINF_SUCCESS;
2057	}
2058
2059	/** @copydoc VDIMAGEBACKEND::pfnRegionListRelease */
2060	static DECLCALLBACK(void) qcowRegionListRelease(void *pBackendData, PCVDREGIONLIST pRegionList)
2061	{
2062	RT_NOREF1(pRegionList);
2063	LogFlowFunc(("pBackendData=%#p pRegionList=%#p\n", pBackendData, pRegionList));
2064	PQCOWIMAGE pThis = (PQCOWIMAGE)pBackendData;
2065	AssertPtr(pThis); RT_NOREF(pThis);
2066
2067	/* Nothing to do here. */
2068	}
2069
2070	/** @copydoc VDIMAGEBACKEND::pfnGetImageFlags */
2071	static DECLCALLBACK(unsigned) qcowGetImageFlags(void *pBackendData)
2072	{
2073	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2074	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2075
2076	AssertPtrReturn(pImage, 0);
2077
2078	LogFlowFunc(("returns %#x\n", pImage->uImageFlags));
2079	return pImage->uImageFlags;
2080	}
2081
2082	/** @copydoc VDIMAGEBACKEND::pfnGetOpenFlags */
2083	static DECLCALLBACK(unsigned) qcowGetOpenFlags(void *pBackendData)
2084	{
2085	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2086	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2087
2088	AssertPtrReturn(pImage, 0);
2089
2090	LogFlowFunc(("returns %#x\n", pImage->uOpenFlags));
2091	return pImage->uOpenFlags;
2092	}
2093
2094	/** @copydoc VDIMAGEBACKEND::pfnSetOpenFlags */
2095	static DECLCALLBACK(int) qcowSetOpenFlags(void *pBackendData, unsigned uOpenFlags)
2096	{
2097	LogFlowFunc(("pBackendData=%#p\n uOpenFlags=%#x", pBackendData, uOpenFlags));
2098	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2099	int rc = VINF_SUCCESS;
2100
2101	/* Image must be opened and the new flags must be valid. */
2102	if (!pImage \|\| (uOpenFlags & ~( VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_INFO
2103	\| VD_OPEN_FLAGS_ASYNC_IO \| VD_OPEN_FLAGS_SHAREABLE
2104	\| VD_OPEN_FLAGS_SEQUENTIAL \| VD_OPEN_FLAGS_SKIP_CONSISTENCY_CHECKS)))
2105	rc = VERR_INVALID_PARAMETER;
2106	else
2107	{
2108	/* Implement this operation via reopening the image. */
2109	rc = qcowFreeImage(pImage, false);
2110	if (RT_SUCCESS(rc))
2111	rc = qcowOpenImage(pImage, uOpenFlags);
2112	}
2113
2114	LogFlowFunc(("returns %Rrc\n", rc));
2115	return rc;
2116	}
2117
2118	/** @copydoc VDIMAGEBACKEND::pfnGetComment */
2119	VD_BACKEND_CALLBACK_GET_COMMENT_DEF_NOT_SUPPORTED(qcowGetComment);
2120
2121	/** @copydoc VDIMAGEBACKEND::pfnSetComment */
2122	VD_BACKEND_CALLBACK_SET_COMMENT_DEF_NOT_SUPPORTED(qcowSetComment, PQCOWIMAGE);
2123
2124	/** @copydoc VDIMAGEBACKEND::pfnGetUuid */
2125	VD_BACKEND_CALLBACK_GET_UUID_DEF_NOT_SUPPORTED(qcowGetUuid);
2126
2127	/** @copydoc VDIMAGEBACKEND::pfnSetUuid */
2128	VD_BACKEND_CALLBACK_SET_UUID_DEF_NOT_SUPPORTED(qcowSetUuid, PQCOWIMAGE);
2129
2130	/** @copydoc VDIMAGEBACKEND::pfnGetModificationUuid */
2131	VD_BACKEND_CALLBACK_GET_UUID_DEF_NOT_SUPPORTED(qcowGetModificationUuid);
2132
2133	/** @copydoc VDIMAGEBACKEND::pfnSetModificationUuid */
2134	VD_BACKEND_CALLBACK_SET_UUID_DEF_NOT_SUPPORTED(qcowSetModificationUuid, PQCOWIMAGE);
2135
2136	/** @copydoc VDIMAGEBACKEND::pfnGetParentUuid */
2137	VD_BACKEND_CALLBACK_GET_UUID_DEF_NOT_SUPPORTED(qcowGetParentUuid);
2138
2139	/** @copydoc VDIMAGEBACKEND::pfnSetParentUuid */
2140	VD_BACKEND_CALLBACK_SET_UUID_DEF_NOT_SUPPORTED(qcowSetParentUuid, PQCOWIMAGE);
2141
2142	/** @copydoc VDIMAGEBACKEND::pfnGetParentModificationUuid */
2143	VD_BACKEND_CALLBACK_GET_UUID_DEF_NOT_SUPPORTED(qcowGetParentModificationUuid);
2144
2145	/** @copydoc VDIMAGEBACKEND::pfnSetParentModificationUuid */
2146	VD_BACKEND_CALLBACK_SET_UUID_DEF_NOT_SUPPORTED(qcowSetParentModificationUuid, PQCOWIMAGE);
2147
2148	/** @copydoc VDIMAGEBACKEND::pfnDump */
2149	static DECLCALLBACK(void) qcowDump(void *pBackendData)
2150	{
2151	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2152
2153	AssertPtrReturnVoid(pImage);
2154	vdIfErrorMessage(pImage->pIfError, "Header: Geometry PCHS=%u/%u/%u LCHS=%u/%u/%u cbSector=%llu\n",
2155	pImage->PCHSGeometry.cCylinders, pImage->PCHSGeometry.cHeads, pImage->PCHSGeometry.cSectors,
2156	pImage->LCHSGeometry.cCylinders, pImage->LCHSGeometry.cHeads, pImage->LCHSGeometry.cSectors,
2157	pImage->cbSize / 512);
2158	}
2159
2160	/** @copydoc VDIMAGEBACKEND::pfnGetParentFilename */
2161	static DECLCALLBACK(int) qcowGetParentFilename(void pBackendData, char *ppszParentFilename)
2162	{
2163	int rc = VINF_SUCCESS;
2164	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2165
2166	AssertPtr(pImage);
2167	if (pImage)
2168	if (pImage->pszBackingFilename)
2169	*ppszParentFilename = RTStrDup(pImage->pszBackingFilename);
2170	else
2171	rc = VERR_NOT_SUPPORTED;
2172	else
2173	rc = VERR_VD_NOT_OPENED;
2174
2175	LogFlowFunc(("returns %Rrc\n", rc));
2176	return rc;
2177	}
2178
2179	/** @copydoc VDIMAGEBACKEND::pfnSetParentFilename */
2180	static DECLCALLBACK(int) qcowSetParentFilename(void pBackendData, const char pszParentFilename)
2181	{
2182	int rc = VINF_SUCCESS;
2183	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2184
2185	AssertPtr(pImage);
2186	if (pImage)
2187	{
2188	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2189	rc = VERR_VD_IMAGE_READ_ONLY;
2190	else if ( pImage->pszBackingFilename
2191	&& (strlen(pszParentFilename) > pImage->cbBackingFilename))
2192	rc = VERR_NOT_SUPPORTED; /* The new filename is longer than the old one. */
2193	else
2194	{
2195	if (pImage->pszBackingFilename)
2196	RTStrFree(pImage->pszBackingFilename);
2197	pImage->pszBackingFilename = RTStrDup(pszParentFilename);
2198	if (!pImage->pszBackingFilename)
2199	rc = VERR_NO_MEMORY;
2200	else
2201	{
2202	if (!pImage->offBackingFilename)
2203	{
2204	/* Allocate new cluster. */
2205	uint64_t offData = qcowClusterAllocate(pImage, 1);
2206
2207	Assert((offData & UINT32_MAX) == offData);
2208	pImage->offBackingFilename = (uint32_t)offData;
2209	pImage->cbBackingFilename = (uint32_t)strlen(pszParentFilename);
2210	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage,
2211	offData + pImage->cbCluster);
2212	}
2213
2214	if (RT_SUCCESS(rc))
2215	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
2216	pImage->offBackingFilename,
2217	pImage->pszBackingFilename,
2218	strlen(pImage->pszBackingFilename));
2219	}
2220	}
2221	}
2222	else
2223	rc = VERR_VD_NOT_OPENED;
2224
2225	LogFlowFunc(("returns %Rrc\n", rc));
2226	return rc;
2227	}
2228
2229
2230
2231	const VDIMAGEBACKEND g_QCowBackend =
2232	{
2233	/* u32Version */
2234	VD_IMGBACKEND_VERSION,
2235	/* pszBackendName */
2236	"QCOW",
2237	/* uBackendCaps */
2238	VD_CAP_FILE \| VD_CAP_VFS \| VD_CAP_CREATE_DYNAMIC \| VD_CAP_DIFF \| VD_CAP_ASYNC,
2239	/* paFileExtensions */
2240	s_aQCowFileExtensions,
2241	/* paConfigInfo */
2242	NULL,
2243	/* pfnProbe */
2244	qcowProbe,
2245	/* pfnOpen */
2246	qcowOpen,
2247	/* pfnCreate */
2248	qcowCreate,
2249	/* pfnRename */
2250	qcowRename,
2251	/* pfnClose */
2252	qcowClose,
2253	/* pfnRead */
2254	qcowRead,
2255	/* pfnWrite */
2256	qcowWrite,
2257	/* pfnFlush */
2258	qcowFlush,
2259	/* pfnDiscard */
2260	NULL,
2261	/* pfnGetVersion */
2262	qcowGetVersion,
2263	/* pfnGetFileSize */
2264	qcowGetFileSize,
2265	/* pfnGetPCHSGeometry */
2266	qcowGetPCHSGeometry,
2267	/* pfnSetPCHSGeometry */
2268	qcowSetPCHSGeometry,
2269	/* pfnGetLCHSGeometry */
2270	qcowGetLCHSGeometry,
2271	/* pfnSetLCHSGeometry */
2272	qcowSetLCHSGeometry,
2273	/* pfnQueryRegions */
2274	qcowQueryRegions,
2275	/* pfnRegionListRelease */
2276	qcowRegionListRelease,
2277	/* pfnGetImageFlags */
2278	qcowGetImageFlags,
2279	/* pfnGetOpenFlags */
2280	qcowGetOpenFlags,
2281	/* pfnSetOpenFlags */
2282	qcowSetOpenFlags,
2283	/* pfnGetComment */
2284	qcowGetComment,
2285	/* pfnSetComment */
2286	qcowSetComment,
2287	/* pfnGetUuid */
2288	qcowGetUuid,
2289	/* pfnSetUuid */
2290	qcowSetUuid,
2291	/* pfnGetModificationUuid */
2292	qcowGetModificationUuid,
2293	/* pfnSetModificationUuid */
2294	qcowSetModificationUuid,
2295	/* pfnGetParentUuid */
2296	qcowGetParentUuid,
2297	/* pfnSetParentUuid */
2298	qcowSetParentUuid,
2299	/* pfnGetParentModificationUuid */
2300	qcowGetParentModificationUuid,
2301	/* pfnSetParentModificationUuid */
2302	qcowSetParentModificationUuid,
2303	/* pfnDump */
2304	qcowDump,
2305	/* pfnGetTimestamp */
2306	NULL,
2307	/* pfnGetParentTimestamp */
2308	NULL,
2309	/* pfnSetParentTimestamp */
2310	NULL,
2311	/* pfnGetParentFilename */
2312	qcowGetParentFilename,
2313	/* pfnSetParentFilename */
2314	qcowSetParentFilename,
2315	/* pfnComposeLocation */
2316	genericFileComposeLocation,
2317	/* pfnComposeName */
2318	genericFileComposeName,
2319	/* pfnCompact */
2320	NULL,
2321	/* pfnResize */
2322	NULL,
2323	/* pfnRepair */
2324	NULL,
2325	/* pfnTraverseMetadata */
2326	NULL,
2327	/* u32VersionEnd */
2328	VD_IMGBACKEND_VERSION
2329	};

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source: vbox/trunk/src/VBox/Storage/QCOW.cpp@ 76985

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