QCOW.cpp@ 44902

Last change on this file since 44902 was 44529, checked in by vboxsync, 12 years ago
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1	/* $Id: QCOW.cpp 44529 2013-02-04 15:54:15Z vboxsync $ */
2	/** @file
3	* QCOW - QCOW Disk image.
4	*/
5
6	/*
7	* Copyright (C) 2011-2013 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 pIoCtx The I/O context.
687	* @param offL2Tbl The offset of the L2 table in the image.
688	* @param ppL2Entry Where to store the L2 table on success.
689	*/
690	static int qcowL2TblCacheFetch(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, uint64_t offL2Tbl,
691	PQCOWL2CACHEENTRY *ppL2Entry)
692	{
693	int rc = VINF_SUCCESS;
694
695	/* Try to fetch the L2 table from the cache first. */
696	PQCOWL2CACHEENTRY pL2Entry = qcowL2TblCacheRetain(pImage, offL2Tbl);
697	if (!pL2Entry)
698	{
699	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
700
701	if (pL2Entry)
702	{
703	/* Read from the image. */
704	PVDMETAXFER pMetaXfer;
705
706	pL2Entry->offL2Tbl = offL2Tbl;
707	rc = vdIfIoIntFileReadMeta(pImage->pIfIo, pImage->pStorage,
708	offL2Tbl, pL2Entry->paL2Tbl,
709	pImage->cbL2Table, pIoCtx,
710	&pMetaXfer, NULL, NULL);
711	if (RT_SUCCESS(rc))
712	{
713	vdIfIoIntMetaXferRelease(pImage->pIfIo, pMetaXfer);
714	#if defined(RT_LITTLE_ENDIAN)
715	qcowTableConvertToHostEndianess(pL2Entry->paL2Tbl, pImage->cL2TableEntries);
716	#endif
717	qcowL2TblCacheEntryInsert(pImage, pL2Entry);
718	}
719	else
720	{
721	qcowL2TblCacheEntryRelease(pL2Entry);
722	qcowL2TblCacheEntryFree(pImage, pL2Entry);
723	}
724	}
725	else
726	rc = VERR_NO_MEMORY;
727	}
728
729	if (RT_SUCCESS(rc))
730	*ppL2Entry = pL2Entry;
731
732	return rc;
733	}
734
735	/**
736	* Sets the L1, L2 and offset bitmasks and L1 and L2 bit shift members.
737	*
738	* @returns nothing.
739	* @param pImage The image instance data.
740	*/
741	static void qcowTableMasksInit(PQCOWIMAGE pImage)
742	{
743	uint32_t cClusterBits, cL2TableBits;
744
745	cClusterBits = qcowGetPowerOfTwo(pImage->cbCluster);
746	cL2TableBits = qcowGetPowerOfTwo(pImage->cL2TableEntries);
747
748	Assert(cClusterBits + cL2TableBits < 64);
749
750	pImage->fOffsetMask = ((uint64_t)pImage->cbCluster - 1);
751	pImage->fL2Mask = ((uint64_t)pImage->cL2TableEntries - 1) << cClusterBits;
752	pImage->cL2Shift = cClusterBits;
753	pImage->cL1Shift = cClusterBits + cL2TableBits;
754	}
755
756	/**
757	* Converts a given logical offset into the
758	*
759	* @returns nothing.
760	* @param pImage The image instance data.
761	* @param off The logical offset to convert.
762	* @param pidxL1 Where to store the index in the L1 table on success.
763	* @param pidxL2 Where to store the index in the L2 table on success.
764	* @param poffCluster Where to store the offset in the cluster on success.
765	*/
766	DECLINLINE(void) qcowConvertLogicalOffset(PQCOWIMAGE pImage, uint64_t off, uint32_t *pidxL1,
767	uint32_t pidxL2, uint32_t poffCluster)
768	{
769	AssertPtr(pidxL1);
770	AssertPtr(pidxL2);
771	AssertPtr(poffCluster);
772
773	*poffCluster = off & pImage->fOffsetMask;
774	*pidxL1 = off >> pImage->cL1Shift;
775	*pidxL2 = (off & pImage->fL2Mask) >> pImage->cL2Shift;
776	}
777
778	/**
779	* Converts Cluster size to a byte size.
780	*
781	* @returns Number of bytes derived from the given number of clusters.
782	* @param pImage The image instance data.
783	* @param cClusters The clusters to convert.
784	*/
785	DECLINLINE(uint64_t) qcowCluster2Byte(PQCOWIMAGE pImage, uint64_t cClusters)
786	{
787	return cClusters * pImage->cbCluster;
788	}
789
790	/**
791	* Converts number of bytes to cluster size rounding to the next cluster.
792	*
793	* @returns Number of bytes derived from the given number of clusters.
794	* @param pImage The image instance data.
795	* @param cb Number of bytes to convert.
796	*/
797	DECLINLINE(uint64_t) qcowByte2Cluster(PQCOWIMAGE pImage, uint64_t cb)
798	{
799	return cb / pImage->cbCluster + (cb % pImage->cbCluster ? 1 : 0);
800	}
801
802	/**
803	* Allocates a new cluster in the image.
804	*
805	* @returns The start offset of the new cluster in the image.
806	* @param pImage The image instance data.
807	* @param cCLusters Number of clusters to allocate.
808	*/
809	DECLINLINE(uint64_t) qcowClusterAllocate(PQCOWIMAGE pImage, uint32_t cClusters)
810	{
811	uint64_t offCluster;
812
813	offCluster = pImage->offNextCluster;
814	pImage->offNextCluster += cClusters*pImage->cbCluster;
815
816	return offCluster;
817	}
818
819	/**
820	* Returns the real image offset for a given cluster or an error if the cluster is not
821	* yet allocated.
822	*
823	* @returns VBox status code.
824	* VERR_VD_BLOCK_FREE if the cluster is not yet allocated.
825	* @param pImage The image instance data.
826	* @param pIoCtx The I/O context.
827	* @param idxL1 The L1 index.
828	* @param idxL2 The L2 index.
829	* @param offCluster Offset inside the cluster.
830	* @param poffImage Where to store the image offset on success;
831	*/
832	static int qcowConvertToImageOffset(PQCOWIMAGE pImage, PVDIOCTX pIoCtx,
833	uint32_t idxL1, uint32_t idxL2,
834	uint32_t offCluster, uint64_t *poffImage)
835	{
836	int rc = VERR_VD_BLOCK_FREE;
837
838	AssertReturn(idxL1 < pImage->cL1TableEntries, VERR_INVALID_PARAMETER);
839	AssertReturn(idxL2 < pImage->cL2TableEntries, VERR_INVALID_PARAMETER);
840
841	if (pImage->paL1Table[idxL1])
842	{
843	PQCOWL2CACHEENTRY pL2Entry;
844
845	rc = qcowL2TblCacheFetch(pImage, pIoCtx, pImage->paL1Table[idxL1], &pL2Entry);
846	if (RT_SUCCESS(rc))
847	{
848	/* Get real file offset. */
849	if (pL2Entry->paL2Tbl[idxL2])
850	{
851	uint64_t off = pL2Entry->paL2Tbl[idxL2];
852
853	/* Strip flags */
854	if (pImage->uVersion == 2)
855	{
856	if (RT_UNLIKELY(off & QCOW_V2_COMPRESSED_FLAG))
857	rc = VERR_NOT_SUPPORTED;
858	else
859	off &= ~(QCOW_V2_COMPRESSED_FLAG \| QCOW_V2_COPIED_FLAG);
860	}
861	else
862	{
863	if (RT_UNLIKELY(off & QCOW_V1_COMPRESSED_FLAG))
864	rc = VERR_NOT_SUPPORTED;
865	else
866	off &= ~QCOW_V1_COMPRESSED_FLAG;
867	}
868
869	*poffImage = off + offCluster;
870	}
871	else
872	rc = VERR_VD_BLOCK_FREE;
873
874	qcowL2TblCacheEntryRelease(pL2Entry);
875	}
876	}
877
878	return rc;
879	}
880
881
882	/**
883	* Internal. Flush image data to disk.
884	*/
885	static int qcowFlushImage(PQCOWIMAGE pImage)
886	{
887	int rc = VINF_SUCCESS;
888
889	if ( pImage->pStorage
890	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
891	&& pImage->cbL1Table)
892	{
893	QCowHeader Header;
894
895	#if defined(RT_LITTLE_ENDIAN)
896	uint64_t paL1TblImg = (uint64_t )RTMemAllocZ(pImage->cbL1Table);
897	if (paL1TblImg)
898	{
899	qcowTableConvertFromHostEndianess(paL1TblImg, pImage->paL1Table,
900	pImage->cL1TableEntries);
901	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
902	pImage->offL1Table, paL1TblImg,
903	pImage->cbL1Table);
904	RTMemFree(paL1TblImg);
905	}
906	else
907	rc = VERR_NO_MEMORY;
908	#else
909	/* Write L1 table directly. */
910	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, pImage->offL1Table,
911	pImage->paL1Table, pImage->cbL1Table);
912	#endif
913	if (RT_SUCCESS(rc))
914	{
915	/* Write header. */
916	size_t cbHeader = 0;
917	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
918	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage, 0, &Header,
919	cbHeader);
920	if (RT_SUCCESS(rc))
921	rc = vdIfIoIntFileFlushSync(pImage->pIfIo, pImage->pStorage);
922	}
923	}
924
925	return rc;
926	}
927
928	/**
929	* Flush image data to disk - version for async I/O.
930	*
931	* @returns VBox status code.
932	* @param pImage The image instance data.
933	* @param pIoCtx The I/o context
934	*/
935	static int qcowFlushImageAsync(PQCOWIMAGE pImage, PVDIOCTX pIoCtx)
936	{
937	int rc = VINF_SUCCESS;
938
939	if ( pImage->pStorage
940	&& !(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
941	{
942	QCowHeader Header;
943
944	#if defined(RT_LITTLE_ENDIAN)
945	uint64_t paL1TblImg = (uint64_t )RTMemAllocZ(pImage->cbL1Table);
946	if (paL1TblImg)
947	{
948	qcowTableConvertFromHostEndianess(paL1TblImg, pImage->paL1Table,
949	pImage->cL1TableEntries);
950	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
951	pImage->offL1Table, paL1TblImg,
952	pImage->cbL1Table, pIoCtx, NULL, NULL);
953	RTMemFree(paL1TblImg);
954	}
955	else
956	rc = VERR_NO_MEMORY;
957	#else
958	/* Write L1 table directly. */
959	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
960	pImage->offL1Table, pImage->paL1Table,
961	pImage->cbL1Table, pIoCtx, NULL, NULL);
962	#endif
963	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
964	{
965	/* Write header. */
966	size_t cbHeader = 0;
967	qcowHdrConvertFromHostEndianess(pImage, &Header, &cbHeader);
968	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
969	0, &Header, cbHeader,
970	pIoCtx, NULL, NULL);
971	if (RT_SUCCESS(rc) \|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
972	rc = vdIfIoIntFileFlush(pImage->pIfIo, pImage->pStorage,
973	pIoCtx, NULL, NULL);
974	}
975	}
976
977	return rc;
978	}
979
980	/**
981	* Internal. Free all allocated space for representing an image except pImage,
982	* and optionally delete the image from disk.
983	*/
984	static int qcowFreeImage(PQCOWIMAGE pImage, bool fDelete)
985	{
986	int rc = VINF_SUCCESS;
987
988	/* Freeing a never allocated image (e.g. because the open failed) is
989	* not signalled as an error. After all nothing bad happens. */
990	if (pImage)
991	{
992	if (pImage->pStorage)
993	{
994	/* No point updating the file that is deleted anyway. */
995	if (!fDelete)
996	qcowFlushImage(pImage);
997
998	vdIfIoIntFileClose(pImage->pIfIo, pImage->pStorage);
999	pImage->pStorage = NULL;
1000	}
1001
1002	if (pImage->paL1Table)
1003	RTMemFree(pImage->paL1Table);
1004
1005	if (pImage->pszBackingFilename)
1006	RTMemFree(pImage->pszBackingFilename);
1007
1008	qcowL2TblCacheDestroy(pImage);
1009
1010	if (fDelete && pImage->pszFilename)
1011	vdIfIoIntFileDelete(pImage->pIfIo, pImage->pszFilename);
1012	}
1013
1014	LogFlowFunc(("returns %Rrc\n", rc));
1015	return rc;
1016	}
1017
1018	/**
1019	* Internal: Open an image, constructing all necessary data structures.
1020	*/
1021	static int qcowOpenImage(PQCOWIMAGE pImage, unsigned uOpenFlags)
1022	{
1023	int rc;
1024
1025	pImage->uOpenFlags = uOpenFlags;
1026
1027	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1028	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1029	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1030
1031	/*
1032	* Open the image.
1033	*/
1034	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename,
1035	VDOpenFlagsToFileOpenFlags(uOpenFlags,
1036	false /* fCreate */),
1037	&pImage->pStorage);
1038	if (RT_FAILURE(rc))
1039	{
1040	/* Do NOT signal an appropriate error here, as the VD layer has the
1041	* choice of retrying the open if it failed. */
1042	goto out;
1043	}
1044
1045	uint64_t cbFile;
1046	QCowHeader Header;
1047	rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
1048	if (RT_FAILURE(rc))
1049	goto out;
1050	if (cbFile > sizeof(Header))
1051	{
1052	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage, 0, &Header, sizeof(Header));
1053	if ( RT_SUCCESS(rc)
1054	&& qcowHdrConvertToHostEndianess(&Header))
1055	{
1056	pImage->offNextCluster = RT_ALIGN_64(cbFile, 512); /* Align image to sector boundary. */
1057	Assert(pImage->offNextCluster >= cbFile);
1058
1059	rc = qcowL2TblCacheCreate(pImage);
1060	AssertRC(rc);
1061
1062	if (Header.u32Version == 1)
1063	{
1064	if (!Header.Version.v1.u32CryptMethod)
1065	{
1066	pImage->uVersion = 1;
1067	pImage->offBackingFilename = Header.Version.v1.u64BackingFileOffset;
1068	pImage->cbBackingFilename = Header.Version.v1.u32BackingFileSize;
1069	pImage->MTime = Header.Version.v1.u32MTime;
1070	pImage->cbSize = Header.Version.v1.u64Size;
1071	pImage->cbCluster = RT_BIT_32(Header.Version.v1.u8ClusterBits);
1072	pImage->cL2TableEntries = RT_BIT_32(Header.Version.v1.u8L2Bits);
1073	pImage->cbL2Table = RT_ALIGN_64(pImage->cL2TableEntries * sizeof(uint64_t), pImage->cbCluster);
1074	pImage->offL1Table = Header.Version.v1.u64L1TableOffset;
1075	pImage->cL1TableEntries = pImage->cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1076	if (pImage->cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1077	pImage->cL1TableEntries++;
1078	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1079	}
1080	else
1081	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1082	N_("QCow: Encrypted image '%s' is not supported"),
1083	pImage->pszFilename);
1084	}
1085	else if (Header.u32Version == 2)
1086	{
1087	if (Header.Version.v2.u32CryptMethod)
1088	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1089	N_("QCow: Encrypted image '%s' is not supported"),
1090	pImage->pszFilename);
1091	else if (Header.Version.v2.u32NbSnapshots)
1092	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1093	N_("QCow: Image '%s' contains snapshots which is not supported"),
1094	pImage->pszFilename);
1095	else
1096	{
1097	pImage->uVersion = 2;
1098	pImage->offBackingFilename = Header.Version.v2.u64BackingFileOffset;
1099	pImage->cbBackingFilename = Header.Version.v2.u32BackingFileSize;
1100	pImage->cbSize = Header.Version.v2.u64Size;
1101	pImage->cbCluster = RT_BIT_32(Header.Version.v2.u32ClusterBits);
1102	pImage->cL2TableEntries = pImage->cbCluster / sizeof(uint64_t);
1103	pImage->cbL2Table = pImage->cbCluster;
1104	pImage->offL1Table = Header.Version.v2.u64L1TableOffset;
1105	pImage->cL1TableEntries = Header.Version.v2.u32L1Size;
1106	pImage->cbL1Table = RT_ALIGN_64(pImage->cL1TableEntries * sizeof(uint64_t), pImage->cbCluster);
1107	pImage->offRefcountTable = Header.Version.v2.u64RefcountTableOffset;
1108	pImage->cbRefcountTable = qcowCluster2Byte(pImage, Header.Version.v2.u32RefcountTableClusters);
1109	pImage->cRefcountTableEntries = pImage->cbRefcountTable / sizeof(uint64_t);
1110	}
1111	}
1112	else
1113	rc = vdIfError(pImage->pIfError, VERR_NOT_SUPPORTED, RT_SRC_POS,
1114	N_("QCow: Image '%s' uses version %u which is not supported"),
1115	pImage->pszFilename, Header.u32Version);
1116
1117	/** @todo: Check that there are no compressed clusters in the image
1118	* (by traversing the L2 tables and checking each offset).
1119	* Refuse to open such images.
1120	*/
1121
1122	if ( RT_SUCCESS(rc)
1123	&& pImage->cbBackingFilename
1124	&& pImage->offBackingFilename)
1125	{
1126	/* Load backing filename from image. */
1127	pImage->pszFilename = (char )RTMemAllocZ(pImage->cbBackingFilename + 1); / +1 for \0 terminator. */
1128	if (pImage->pszFilename)
1129	{
1130	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1131	pImage->offBackingFilename, pImage->pszBackingFilename,
1132	pImage->cbBackingFilename);
1133	}
1134	else
1135	rc = VERR_NO_MEMORY;
1136	}
1137
1138	if ( RT_SUCCESS(rc)
1139	&& pImage->cbRefcountTable
1140	&& pImage->offRefcountTable)
1141	{
1142	/* Load refcount table. */
1143	Assert(pImage->cRefcountTableEntries);
1144	pImage->paRefcountTable = (uint64_t *)RTMemAllocZ(pImage->cbRefcountTable);
1145	if (RT_LIKELY(pImage->paRefcountTable))
1146	{
1147	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1148	pImage->offRefcountTable, pImage->paRefcountTable,
1149	pImage->cbRefcountTable);
1150	if (RT_SUCCESS(rc))
1151	qcowTableConvertToHostEndianess(pImage->paRefcountTable,
1152	pImage->cRefcountTableEntries);
1153	else
1154	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1155	N_("QCow: Reading refcount table of image '%s' failed"),
1156	pImage->pszFilename);
1157	}
1158	else
1159	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1160	N_("QCow: Allocating memory for refcount table of image '%s' failed"),
1161	pImage->pszFilename);
1162	}
1163
1164	if (RT_SUCCESS(rc))
1165	{
1166	qcowTableMasksInit(pImage);
1167
1168	/* Allocate L1 table. */
1169	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1170	if (pImage->paL1Table)
1171	{
1172	/* Read from the image. */
1173	rc = vdIfIoIntFileReadSync(pImage->pIfIo, pImage->pStorage,
1174	pImage->offL1Table, pImage->paL1Table,
1175	pImage->cbL1Table);
1176	if (RT_SUCCESS(rc))
1177	qcowTableConvertToHostEndianess(pImage->paL1Table, pImage->cL1TableEntries);
1178	else
1179	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS,
1180	N_("QCow: Reading the L1 table for image '%s' failed"),
1181	pImage->pszFilename);
1182	}
1183	else
1184	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS,
1185	N_("QCow: Out of memory allocating L1 table for image '%s'"),
1186	pImage->pszFilename);
1187	}
1188	}
1189	else if (RT_SUCCESS(rc))
1190	rc = VERR_VD_GEN_INVALID_HEADER;
1191	}
1192	else
1193	rc = VERR_VD_GEN_INVALID_HEADER;
1194
1195	out:
1196	if (RT_FAILURE(rc))
1197	qcowFreeImage(pImage, false);
1198	return rc;
1199	}
1200
1201	/**
1202	* Internal: Create a qcow image.
1203	*/
1204	static int qcowCreateImage(PQCOWIMAGE pImage, uint64_t cbSize,
1205	unsigned uImageFlags, const char *pszComment,
1206	PCVDGEOMETRY pPCHSGeometry,
1207	PCVDGEOMETRY pLCHSGeometry, unsigned uOpenFlags,
1208	PFNVDPROGRESS pfnProgress, void *pvUser,
1209	unsigned uPercentStart, unsigned uPercentSpan)
1210	{
1211	int rc;
1212	int32_t fOpen;
1213
1214	if (uImageFlags & VD_IMAGE_FLAGS_FIXED)
1215	{
1216	rc = vdIfError(pImage->pIfError, VERR_VD_INVALID_TYPE, RT_SRC_POS, N_("QCow: cannot create fixed image '%s'"), pImage->pszFilename);
1217	goto out;
1218	}
1219
1220	pImage->uOpenFlags = uOpenFlags & ~VD_OPEN_FLAGS_READONLY;
1221	pImage->uImageFlags = uImageFlags;
1222	pImage->PCHSGeometry = *pPCHSGeometry;
1223	pImage->LCHSGeometry = *pLCHSGeometry;
1224
1225	pImage->pIfError = VDIfErrorGet(pImage->pVDIfsDisk);
1226	pImage->pIfIo = VDIfIoIntGet(pImage->pVDIfsImage);
1227	AssertPtrReturn(pImage->pIfIo, VERR_INVALID_PARAMETER);
1228
1229	/* Create image file. */
1230	fOpen = VDOpenFlagsToFileOpenFlags(pImage->uOpenFlags, true /* fCreate */);
1231	rc = vdIfIoIntFileOpen(pImage->pIfIo, pImage->pszFilename, fOpen, &pImage->pStorage);
1232	if (RT_FAILURE(rc))
1233	{
1234	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: cannot create image '%s'"), pImage->pszFilename);
1235	goto out;
1236	}
1237
1238	/* Init image state. */
1239	pImage->uVersion = 1; /* We create only version 1 images at the moment. */
1240	pImage->cbSize = cbSize;
1241	pImage->cbCluster = QCOW_CLUSTER_SIZE_DEFAULT;
1242	pImage->cbL2Table = qcowCluster2Byte(pImage, QCOW_L2_CLUSTERS_DEFAULT);
1243	pImage->cL2TableEntries = pImage->cbL2Table / sizeof(uint64_t);
1244	pImage->cL1TableEntries = cbSize / (pImage->cbCluster * pImage->cL2TableEntries);
1245	if (cbSize % (pImage->cbCluster * pImage->cL2TableEntries))
1246	pImage->cL1TableEntries++;
1247	pImage->cbL1Table = pImage->cL1TableEntries * sizeof(uint64_t);
1248	pImage->offL1Table = QCOW_V1_HDR_SIZE;
1249	pImage->cbBackingFilename = 0;
1250	pImage->offBackingFilename = 0;
1251	pImage->offNextCluster = RT_ALIGN_64(QCOW_V1_HDR_SIZE + pImage->cbL1Table, pImage->cbCluster);
1252	qcowTableMasksInit(pImage);
1253
1254	/* Init L1 table. */
1255	pImage->paL1Table = (uint64_t *)RTMemAllocZ(pImage->cbL1Table);
1256	if (!pImage->paL1Table)
1257	{
1258	rc = vdIfError(pImage->pIfError, VERR_NO_MEMORY, RT_SRC_POS, N_("QCow: cannot allocate memory for L1 table of image '%s'"),
1259	pImage->pszFilename);
1260	goto out;
1261	}
1262
1263	rc = qcowL2TblCacheCreate(pImage);
1264	if (RT_FAILURE(rc))
1265	{
1266	rc = vdIfError(pImage->pIfError, rc, RT_SRC_POS, N_("QCow: Failed to create L2 cache for image '%s'"),
1267	pImage->pszFilename);
1268	goto out;
1269	}
1270
1271	if (RT_SUCCESS(rc) && pfnProgress)
1272	pfnProgress(pvUser, uPercentStart + uPercentSpan * 98 / 100);
1273
1274	rc = qcowFlushImage(pImage);
1275	if (RT_SUCCESS(rc))
1276	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pImage->offNextCluster);
1277
1278	out:
1279	if (RT_SUCCESS(rc) && pfnProgress)
1280	pfnProgress(pvUser, uPercentStart + uPercentSpan);
1281
1282	if (RT_FAILURE(rc))
1283	qcowFreeImage(pImage, rc != VERR_ALREADY_EXISTS);
1284	return rc;
1285	}
1286
1287	/**
1288	* Rollback anything done during async cluster allocation.
1289	*
1290	* @returns VBox status code.
1291	* @param pImage The image instance data.
1292	* @param pIoCtx The I/O context.
1293	* @param pClusterAlloc The cluster allocation to rollback.
1294	*/
1295	static int qcowAsyncClusterAllocRollback(PQCOWIMAGE pImage, PVDIOCTX pIoCtx, PQCOWCLUSTERASYNCALLOC pClusterAlloc)
1296	{
1297	int rc = VINF_SUCCESS;
1298
1299	switch (pClusterAlloc->enmAllocState)
1300	{
1301	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1302	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1303	{
1304	/* Assumption right now is that the L1 table is not modified if the link fails. */
1305	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1306	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1307	qcowL2TblCacheEntryFree(pImage, pClusterAlloc->pL2Entry); /* Free it, it is not in the cache yet. */
1308	}
1309	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1310	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1311	{
1312	/* Assumption right now is that the L2 table is not modified if the link fails. */
1313	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, pClusterAlloc->offNextClusterOld);
1314	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry); /* Release L2 cache entry. */
1315	break;
1316	}
1317	default:
1318	AssertMsgFailed(("Invalid cluster allocation state %d\n", pClusterAlloc->enmAllocState));
1319	rc = VERR_INVALID_STATE;
1320	}
1321
1322	RTMemFree(pClusterAlloc);
1323	return rc;
1324	}
1325
1326	/**
1327	* Updates the state of the async cluster allocation.
1328	*
1329	* @returns VBox status code.
1330	* @param pBackendData The opaque backend data.
1331	* @param pIoCtx I/O context associated with this request.
1332	* @param pvUser Opaque user data passed during a read/write request.
1333	* @param rcReq Status code for the completed request.
1334	*/
1335	static DECLCALLBACK(int) qcowAsyncClusterAllocUpdate(void pBackendData, PVDIOCTX pIoCtx, void pvUser, int rcReq)
1336	{
1337	int rc = VINF_SUCCESS;
1338	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1339	PQCOWCLUSTERASYNCALLOC pClusterAlloc = (PQCOWCLUSTERASYNCALLOC)pvUser;
1340
1341	if (RT_FAILURE(rcReq))
1342	return qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1343
1344	AssertPtr(pClusterAlloc->pL2Entry);
1345
1346	switch (pClusterAlloc->enmAllocState)
1347	{
1348	case QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC:
1349	{
1350	uint64_t offUpdateLe = RT_H2BE_U64(pClusterAlloc->pL2Entry->offL2Tbl);
1351
1352	/* Update the link in the on disk L1 table now. */
1353	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_LINK;
1354	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
1355	pImage->offL1Table + pClusterAlloc->idxL1*sizeof(uint64_t),
1356	&offUpdateLe, sizeof(uint64_t), pIoCtx,
1357	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1358	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1359	break;
1360	else if (RT_FAILURE(rc))
1361	{
1362	/* Rollback. */
1363	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1364	break;
1365	}
1366	/* Success, fall through. */
1367	}
1368	case QCOWCLUSTERASYNCALLOCSTATE_L2_LINK:
1369	{
1370	/* L2 link updated in L1 , save L2 entry in cache and allocate new user data cluster. */
1371	uint64_t offData = qcowClusterAllocate(pImage, 1);
1372
1373	/* Update the link in the in memory L1 table now. */
1374	pImage->paL1Table[pClusterAlloc->idxL1] = pClusterAlloc->pL2Entry->offL2Tbl;
1375	qcowL2TblCacheEntryInsert(pImage, pClusterAlloc->pL2Entry);
1376
1377	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
1378	pClusterAlloc->offNextClusterOld = offData;
1379	pClusterAlloc->offClusterNew = offData;
1380
1381	/* Write data. */
1382	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1383	offData, pIoCtx, pClusterAlloc->cbToWrite,
1384	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1385	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1386	break;
1387	else if (RT_FAILURE(rc))
1388	{
1389	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1390	RTMemFree(pClusterAlloc);
1391	break;
1392	}
1393	}
1394	case QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC:
1395	{
1396	uint64_t offUpdateLe = RT_H2BE_U64(pClusterAlloc->offClusterNew);
1397
1398	pClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_LINK;
1399
1400	/* Link L2 table and update it. */
1401	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
1402	pImage->paL1Table[pClusterAlloc->idxL1] + pClusterAlloc->idxL2*sizeof(uint64_t),
1403	&offUpdateLe, sizeof(uint64_t), pIoCtx,
1404	qcowAsyncClusterAllocUpdate, pClusterAlloc);
1405	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1406	break;
1407	else if (RT_FAILURE(rc))
1408	{
1409	qcowAsyncClusterAllocRollback(pImage, pIoCtx, pClusterAlloc);
1410	RTMemFree(pClusterAlloc);
1411	break;
1412	}
1413	}
1414	case QCOWCLUSTERASYNCALLOCSTATE_USER_LINK:
1415	{
1416	/* Everything done without errors, signal completion. */
1417	pClusterAlloc->pL2Entry->paL2Tbl[pClusterAlloc->idxL2] = pClusterAlloc->offClusterNew;
1418	qcowL2TblCacheEntryRelease(pClusterAlloc->pL2Entry);
1419	RTMemFree(pClusterAlloc);
1420	rc = VINF_SUCCESS;
1421	break;
1422	}
1423	default:
1424	AssertMsgFailed(("Invalid async cluster allocation state %d\n",
1425	pClusterAlloc->enmAllocState));
1426	}
1427
1428	return rc;
1429	}
1430
1431	/** @copydoc VBOXHDDBACKEND::pfnCheckIfValid */
1432	static int qcowCheckIfValid(const char *pszFilename, PVDINTERFACE pVDIfsDisk,
1433	PVDINTERFACE pVDIfsImage, VDTYPE *penmType)
1434	{
1435	LogFlowFunc(("pszFilename=\"%s\" pVDIfsDisk=%#p pVDIfsImage=%#p\n", pszFilename, pVDIfsDisk, pVDIfsImage));
1436	PVDIOSTORAGE pStorage = NULL;
1437	uint64_t cbFile;
1438	int rc = VINF_SUCCESS;
1439
1440	/* Get I/O interface. */
1441	PVDINTERFACEIOINT pIfIo = VDIfIoIntGet(pVDIfsImage);
1442	AssertPtrReturn(pIfIo, VERR_INVALID_PARAMETER);
1443
1444	if ( !VALID_PTR(pszFilename)
1445	\|\| !*pszFilename)
1446	{
1447	rc = VERR_INVALID_PARAMETER;
1448	goto out;
1449	}
1450
1451	/*
1452	* Open the file and read the footer.
1453	*/
1454	rc = vdIfIoIntFileOpen(pIfIo, pszFilename,
1455	VDOpenFlagsToFileOpenFlags(VD_OPEN_FLAGS_READONLY,
1456	false /* fCreate */),
1457	&pStorage);
1458	if (RT_SUCCESS(rc))
1459	rc = vdIfIoIntFileGetSize(pIfIo, pStorage, &cbFile);
1460
1461	if ( RT_SUCCESS(rc)
1462	&& cbFile > sizeof(QCowHeader))
1463	{
1464	QCowHeader Header;
1465
1466	rc = vdIfIoIntFileReadSync(pIfIo, pStorage, 0, &Header, sizeof(Header));
1467	if ( RT_SUCCESS(rc)
1468	&& qcowHdrConvertToHostEndianess(&Header))
1469	{
1470	*penmType = VDTYPE_HDD;
1471	rc = VINF_SUCCESS;
1472	}
1473	else
1474	rc = VERR_VD_GEN_INVALID_HEADER;
1475	}
1476	else
1477	rc = VERR_VD_GEN_INVALID_HEADER;
1478
1479	if (pStorage)
1480	vdIfIoIntFileClose(pIfIo, pStorage);
1481
1482	out:
1483	LogFlowFunc(("returns %Rrc\n", rc));
1484	return rc;
1485	}
1486
1487	/** @copydoc VBOXHDDBACKEND::pfnOpen */
1488	static int qcowOpen(const char *pszFilename, unsigned uOpenFlags,
1489	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1490	VDTYPE enmType, void **ppBackendData)
1491	{
1492	LogFlowFunc(("pszFilename=\"%s\" uOpenFlags=%#x pVDIfsDisk=%#p pVDIfsImage=%#p ppBackendData=%#p\n", pszFilename, uOpenFlags, pVDIfsDisk, pVDIfsImage, ppBackendData));
1493	int rc;
1494	PQCOWIMAGE pImage;
1495
1496	/* Check open flags. All valid flags are supported. */
1497	if (uOpenFlags & ~VD_OPEN_FLAGS_MASK)
1498	{
1499	rc = VERR_INVALID_PARAMETER;
1500	goto out;
1501	}
1502
1503	/* Check remaining arguments. */
1504	if ( !VALID_PTR(pszFilename)
1505	\|\| !*pszFilename)
1506	{
1507	rc = VERR_INVALID_PARAMETER;
1508	goto out;
1509	}
1510
1511
1512	pImage = (PQCOWIMAGE)RTMemAllocZ(sizeof(QCOWIMAGE));
1513	if (!pImage)
1514	{
1515	rc = VERR_NO_MEMORY;
1516	goto out;
1517	}
1518	pImage->pszFilename = pszFilename;
1519	pImage->pStorage = NULL;
1520	pImage->pVDIfsDisk = pVDIfsDisk;
1521	pImage->pVDIfsImage = pVDIfsImage;
1522
1523	rc = qcowOpenImage(pImage, uOpenFlags);
1524	if (RT_SUCCESS(rc))
1525	*ppBackendData = pImage;
1526	else
1527	RTMemFree(pImage);
1528
1529	out:
1530	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1531	return rc;
1532	}
1533
1534	/** @copydoc VBOXHDDBACKEND::pfnCreate */
1535	static int qcowCreate(const char *pszFilename, uint64_t cbSize,
1536	unsigned uImageFlags, const char *pszComment,
1537	PCVDGEOMETRY pPCHSGeometry, PCVDGEOMETRY pLCHSGeometry,
1538	PCRTUUID pUuid, unsigned uOpenFlags,
1539	unsigned uPercentStart, unsigned uPercentSpan,
1540	PVDINTERFACE pVDIfsDisk, PVDINTERFACE pVDIfsImage,
1541	PVDINTERFACE pVDIfsOperation, void **ppBackendData)
1542	{
1543	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",
1544	pszFilename, cbSize, uImageFlags, pszComment, pPCHSGeometry, pLCHSGeometry, pUuid, uOpenFlags, uPercentStart, uPercentSpan, pVDIfsDisk, pVDIfsImage, pVDIfsOperation, ppBackendData));
1545	int rc;
1546	PQCOWIMAGE pImage;
1547
1548	PFNVDPROGRESS pfnProgress = NULL;
1549	void *pvUser = NULL;
1550	PVDINTERFACEPROGRESS pIfProgress = VDIfProgressGet(pVDIfsOperation);
1551	if (pIfProgress)
1552	{
1553	pfnProgress = pIfProgress->pfnProgress;
1554	pvUser = pIfProgress->Core.pvUser;
1555	}
1556
1557	/* Check open flags. All valid flags are supported. */
1558	if (uOpenFlags & ~VD_OPEN_FLAGS_MASK)
1559	{
1560	rc = VERR_INVALID_PARAMETER;
1561	goto out;
1562	}
1563
1564	/* Check remaining arguments. */
1565	if ( !VALID_PTR(pszFilename)
1566	\|\| !*pszFilename
1567	\|\| !VALID_PTR(pPCHSGeometry)
1568	\|\| !VALID_PTR(pLCHSGeometry))
1569	{
1570	rc = VERR_INVALID_PARAMETER;
1571	goto out;
1572	}
1573
1574	pImage = (PQCOWIMAGE)RTMemAllocZ(sizeof(QCOWIMAGE));
1575	if (!pImage)
1576	{
1577	rc = VERR_NO_MEMORY;
1578	goto out;
1579	}
1580	pImage->pszFilename = pszFilename;
1581	pImage->pStorage = NULL;
1582	pImage->pVDIfsDisk = pVDIfsDisk;
1583	pImage->pVDIfsImage = pVDIfsImage;
1584
1585	rc = qcowCreateImage(pImage, cbSize, uImageFlags, pszComment,
1586	pPCHSGeometry, pLCHSGeometry, uOpenFlags,
1587	pfnProgress, pvUser, uPercentStart, uPercentSpan);
1588	if (RT_SUCCESS(rc))
1589	{
1590	/* So far the image is opened in read/write mode. Make sure the
1591	* image is opened in read-only mode if the caller requested that. */
1592	if (uOpenFlags & VD_OPEN_FLAGS_READONLY)
1593	{
1594	qcowFreeImage(pImage, false);
1595	rc = qcowOpenImage(pImage, uOpenFlags);
1596	if (RT_FAILURE(rc))
1597	{
1598	RTMemFree(pImage);
1599	goto out;
1600	}
1601	}
1602	*ppBackendData = pImage;
1603	}
1604	else
1605	RTMemFree(pImage);
1606
1607	out:
1608	LogFlowFunc(("returns %Rrc (pBackendData=%#p)\n", rc, *ppBackendData));
1609	return rc;
1610	}
1611
1612	/** @copydoc VBOXHDDBACKEND::pfnRename */
1613	static int qcowRename(void pBackendData, const char pszFilename)
1614	{
1615	LogFlowFunc(("pBackendData=%#p pszFilename=%#p\n", pBackendData, pszFilename));
1616	int rc = VINF_SUCCESS;
1617	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1618
1619	/* Check arguments. */
1620	if ( !pImage
1621	\|\| !pszFilename
1622	\|\| !*pszFilename)
1623	{
1624	rc = VERR_INVALID_PARAMETER;
1625	goto out;
1626	}
1627
1628	/* Close the image. */
1629	rc = qcowFreeImage(pImage, false);
1630	if (RT_FAILURE(rc))
1631	goto out;
1632
1633	/* Rename the file. */
1634	rc = vdIfIoIntFileMove(pImage->pIfIo, pImage->pszFilename, pszFilename, 0);
1635	if (RT_FAILURE(rc))
1636	{
1637	/* The move failed, try to reopen the original image. */
1638	int rc2 = qcowOpenImage(pImage, pImage->uOpenFlags);
1639	if (RT_FAILURE(rc2))
1640	rc = rc2;
1641
1642	goto out;
1643	}
1644
1645	/* Update pImage with the new information. */
1646	pImage->pszFilename = pszFilename;
1647
1648	/* Open the old image with new name. */
1649	rc = qcowOpenImage(pImage, pImage->uOpenFlags);
1650	if (RT_FAILURE(rc))
1651	goto out;
1652
1653	out:
1654	LogFlowFunc(("returns %Rrc\n", rc));
1655	return rc;
1656	}
1657
1658	/** @copydoc VBOXHDDBACKEND::pfnClose */
1659	static int qcowClose(void *pBackendData, bool fDelete)
1660	{
1661	LogFlowFunc(("pBackendData=%#p fDelete=%d\n", pBackendData, fDelete));
1662	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1663	int rc;
1664
1665	rc = qcowFreeImage(pImage, fDelete);
1666	RTMemFree(pImage);
1667
1668	LogFlowFunc(("returns %Rrc\n", rc));
1669	return rc;
1670	}
1671
1672	static int qcowRead(void *pBackendData, uint64_t uOffset, size_t cbToRead,
1673	PVDIOCTX pIoCtx, size_t *pcbActuallyRead)
1674	{
1675	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToRead=%zu pcbActuallyRead=%#p\n",
1676	pBackendData, uOffset, pIoCtx, cbToRead, pcbActuallyRead));
1677	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1678	uint32_t offCluster = 0;
1679	uint32_t idxL1 = 0;
1680	uint32_t idxL2 = 0;
1681	uint64_t offFile = 0;
1682	int rc;
1683
1684	AssertPtr(pImage);
1685	Assert(uOffset % 512 == 0);
1686	Assert(cbToRead % 512 == 0);
1687
1688	if (!VALID_PTR(pIoCtx) \|\| !cbToRead)
1689	{
1690	rc = VERR_INVALID_PARAMETER;
1691	goto out;
1692	}
1693
1694	if ( uOffset + cbToRead > pImage->cbSize
1695	\|\| cbToRead == 0)
1696	{
1697	rc = VERR_INVALID_PARAMETER;
1698	goto out;
1699	}
1700
1701	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1702
1703	/* Clip read size to remain in the cluster. */
1704	cbToRead = RT_MIN(cbToRead, pImage->cbCluster - offCluster);
1705
1706	/* Get offset in image. */
1707	rc = qcowConvertToImageOffset(pImage, pIoCtx, idxL1, idxL2, offCluster, &offFile);
1708	if (RT_SUCCESS(rc))
1709	rc = vdIfIoIntFileReadUser(pImage->pIfIo, pImage->pStorage, offFile,
1710	pIoCtx, cbToRead);
1711
1712	if ( ( RT_SUCCESS(rc)
1713	\|\| rc == VERR_VD_BLOCK_FREE
1714	\|\| rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1715	&& pcbActuallyRead)
1716	*pcbActuallyRead = cbToRead;
1717
1718	out:
1719	LogFlowFunc(("returns %Rrc\n", rc));
1720	return rc;
1721	}
1722
1723	static int qcowWrite(void *pBackendData, uint64_t uOffset, size_t cbToWrite,
1724	PVDIOCTX pIoCtx, size_t pcbWriteProcess, size_t pcbPreRead,
1725	size_t *pcbPostRead, unsigned fWrite)
1726	{
1727	LogFlowFunc(("pBackendData=%#p uOffset=%llu pIoCtx=%#p cbToWrite=%zu pcbWriteProcess=%#p pcbPreRead=%#p pcbPostRead=%#p\n",
1728	pBackendData, uOffset, pIoCtx, cbToWrite, pcbWriteProcess, pcbPreRead, pcbPostRead));
1729	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1730	uint32_t offCluster = 0;
1731	uint32_t idxL1 = 0;
1732	uint32_t idxL2 = 0;
1733	uint64_t offImage = 0;
1734	int rc = VINF_SUCCESS;
1735
1736	AssertPtr(pImage);
1737	Assert(!(uOffset % 512));
1738	Assert(!(cbToWrite % 512));
1739
1740	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
1741	{
1742	rc = VERR_VD_IMAGE_READ_ONLY;
1743	goto out;
1744	}
1745
1746	if (!VALID_PTR(pIoCtx) \|\| !cbToWrite)
1747	{
1748	rc = VERR_INVALID_PARAMETER;
1749	goto out;
1750	}
1751
1752	if ( uOffset + cbToWrite > pImage->cbSize
1753	\|\| cbToWrite == 0)
1754	{
1755	rc = VERR_INVALID_PARAMETER;
1756	goto out;
1757	}
1758
1759	/* Convert offset to L1, L2 index and cluster offset. */
1760	qcowConvertLogicalOffset(pImage, uOffset, &idxL1, &idxL2, &offCluster);
1761
1762	/* Clip write size to remain in the cluster. */
1763	cbToWrite = RT_MIN(cbToWrite, pImage->cbCluster - offCluster);
1764	Assert(!(cbToWrite % 512));
1765
1766	/* Get offset in image. */
1767	rc = qcowConvertToImageOffset(pImage, pIoCtx, idxL1, idxL2, offCluster, &offImage);
1768	if (RT_SUCCESS(rc))
1769	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1770	offImage, pIoCtx, cbToWrite, NULL, NULL);
1771	else if (rc == VERR_VD_BLOCK_FREE)
1772	{
1773	if ( cbToWrite == pImage->cbCluster
1774	&& !(fWrite & VD_WRITE_NO_ALLOC))
1775	{
1776	PQCOWL2CACHEENTRY pL2Entry = NULL;
1777
1778	/* Full cluster write to previously unallocated cluster.
1779	* Allocate cluster and write data. */
1780	Assert(!offCluster);
1781
1782	do
1783	{
1784	uint64_t idxUpdateLe = 0;
1785
1786	/* Check if we have to allocate a new cluster for L2 tables. */
1787	if (!pImage->paL1Table[idxL1])
1788	{
1789	uint64_t offL2Tbl;
1790	PQCOWCLUSTERASYNCALLOC pL2ClusterAlloc = NULL;
1791
1792	/* Allocate new async cluster allocation state. */
1793	pL2ClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
1794	if (RT_UNLIKELY(!pL2ClusterAlloc))
1795	{
1796	rc = VERR_NO_MEMORY;
1797	break;
1798	}
1799
1800	pL2Entry = qcowL2TblCacheEntryAlloc(pImage);
1801	if (!pL2Entry)
1802	{
1803	rc = VERR_NO_MEMORY;
1804	RTMemFree(pL2ClusterAlloc);
1805	break;
1806	}
1807
1808	offL2Tbl = qcowClusterAllocate(pImage, qcowByte2Cluster(pImage, pImage->cbL2Table));
1809	pL2Entry->offL2Tbl = offL2Tbl;
1810	memset(pL2Entry->paL2Tbl, 0, pImage->cbL2Table);
1811
1812	pL2ClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_L2_ALLOC;
1813	pL2ClusterAlloc->offNextClusterOld = offL2Tbl;
1814	pL2ClusterAlloc->offClusterNew = offL2Tbl;
1815	pL2ClusterAlloc->idxL1 = idxL1;
1816	pL2ClusterAlloc->idxL2 = idxL2;
1817	pL2ClusterAlloc->cbToWrite = cbToWrite;
1818	pL2ClusterAlloc->pL2Entry = pL2Entry;
1819
1820	/*
1821	* Write the L2 table first and link to the L1 table afterwards.
1822	* If something unexpected happens the worst case which can happen
1823	* is a leak of some clusters.
1824	*/
1825	rc = vdIfIoIntFileWriteMeta(pImage->pIfIo, pImage->pStorage,
1826	offL2Tbl, pL2Entry->paL2Tbl, pImage->cbL2Table, pIoCtx,
1827	qcowAsyncClusterAllocUpdate, pL2ClusterAlloc);
1828	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1829	break;
1830	else if (RT_FAILURE(rc))
1831	{
1832	RTMemFree(pL2ClusterAlloc);
1833	qcowL2TblCacheEntryFree(pImage, pL2Entry);
1834	break;
1835	}
1836
1837	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pL2ClusterAlloc, rc);
1838	}
1839	else
1840	{
1841	rc = qcowL2TblCacheFetch(pImage, pIoCtx, pImage->paL1Table[idxL1],
1842	&pL2Entry);
1843	if (RT_SUCCESS(rc))
1844	{
1845	PQCOWCLUSTERASYNCALLOC pDataClusterAlloc = NULL;
1846
1847	/* Allocate new async cluster allocation state. */
1848	pDataClusterAlloc = (PQCOWCLUSTERASYNCALLOC)RTMemAllocZ(sizeof(QCOWCLUSTERASYNCALLOC));
1849	if (RT_UNLIKELY(!pDataClusterAlloc))
1850	{
1851	rc = VERR_NO_MEMORY;
1852	break;
1853	}
1854
1855	/* Allocate new cluster for the data. */
1856	uint64_t offData = qcowClusterAllocate(pImage, 1);
1857
1858	pDataClusterAlloc->enmAllocState = QCOWCLUSTERASYNCALLOCSTATE_USER_ALLOC;
1859	pDataClusterAlloc->offNextClusterOld = offData;
1860	pDataClusterAlloc->offClusterNew = offData;
1861	pDataClusterAlloc->idxL1 = idxL1;
1862	pDataClusterAlloc->idxL2 = idxL2;
1863	pDataClusterAlloc->cbToWrite = cbToWrite;
1864	pDataClusterAlloc->pL2Entry = pL2Entry;
1865
1866	/* Write data. */
1867	rc = vdIfIoIntFileWriteUser(pImage->pIfIo, pImage->pStorage,
1868	offData, pIoCtx, cbToWrite,
1869	qcowAsyncClusterAllocUpdate, pDataClusterAlloc);
1870	if (rc == VERR_VD_ASYNC_IO_IN_PROGRESS)
1871	break;
1872	else if (RT_FAILURE(rc))
1873	{
1874	RTMemFree(pDataClusterAlloc);
1875	break;
1876	}
1877
1878	rc = qcowAsyncClusterAllocUpdate(pImage, pIoCtx, pDataClusterAlloc, rc);
1879	}
1880	}
1881
1882	} while (0);
1883
1884	*pcbPreRead = 0;
1885	*pcbPostRead = 0;
1886	}
1887	else
1888	{
1889	/* Trying to do a partial write to an unallocated cluster. Don't do
1890	* anything except letting the upper layer know what to do. */
1891	*pcbPreRead = offCluster;
1892	pcbPostRead = pImage->cbCluster - cbToWrite - pcbPreRead;
1893	}
1894	}
1895
1896	if (pcbWriteProcess)
1897	*pcbWriteProcess = cbToWrite;
1898
1899
1900	out:
1901	LogFlowFunc(("returns %Rrc\n", rc));
1902	return rc;
1903	}
1904
1905	static 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	Assert(pImage);
1912
1913	if (VALID_PTR(pIoCtx))
1914	rc = qcowFlushImageAsync(pImage, pIoCtx);
1915	else
1916	rc = VERR_INVALID_PARAMETER;
1917
1918	LogFlowFunc(("returns %Rrc\n", rc));
1919	return rc;
1920	}
1921
1922	/** @copydoc VBOXHDDBACKEND::pfnGetVersion */
1923	static unsigned qcowGetVersion(void *pBackendData)
1924	{
1925	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1926	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1927
1928	AssertPtr(pImage);
1929
1930	if (pImage)
1931	return pImage->uVersion;
1932	else
1933	return 0;
1934	}
1935
1936	/** @copydoc VBOXHDDBACKEND::pfnGetSize */
1937	static uint64_t qcowGetSize(void *pBackendData)
1938	{
1939	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1940	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1941	uint64_t cb = 0;
1942
1943	AssertPtr(pImage);
1944
1945	if (pImage && pImage->pStorage)
1946	cb = pImage->cbSize;
1947
1948	LogFlowFunc(("returns %llu\n", cb));
1949	return cb;
1950	}
1951
1952	/** @copydoc VBOXHDDBACKEND::pfnGetFileSize */
1953	static uint64_t qcowGetFileSize(void *pBackendData)
1954	{
1955	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
1956	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1957	uint64_t cb = 0;
1958
1959	AssertPtr(pImage);
1960
1961	if (pImage)
1962	{
1963	uint64_t cbFile;
1964	if (pImage->pStorage)
1965	{
1966	int rc = vdIfIoIntFileGetSize(pImage->pIfIo, pImage->pStorage, &cbFile);
1967	if (RT_SUCCESS(rc))
1968	cb += cbFile;
1969	}
1970	}
1971
1972	LogFlowFunc(("returns %lld\n", cb));
1973	return cb;
1974	}
1975
1976	/** @copydoc VBOXHDDBACKEND::pfnGetPCHSGeometry */
1977	static int qcowGetPCHSGeometry(void *pBackendData,
1978	PVDGEOMETRY pPCHSGeometry)
1979	{
1980	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p\n", pBackendData, pPCHSGeometry));
1981	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
1982	int rc;
1983
1984	AssertPtr(pImage);
1985
1986	if (pImage)
1987	{
1988	if (pImage->PCHSGeometry.cCylinders)
1989	{
1990	*pPCHSGeometry = pImage->PCHSGeometry;
1991	rc = VINF_SUCCESS;
1992	}
1993	else
1994	rc = VERR_VD_GEOMETRY_NOT_SET;
1995	}
1996	else
1997	rc = VERR_VD_NOT_OPENED;
1998
1999	LogFlowFunc(("returns %Rrc (PCHS=%u/%u/%u)\n", rc, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
2000	return rc;
2001	}
2002
2003	/** @copydoc VBOXHDDBACKEND::pfnSetPCHSGeometry */
2004	static int qcowSetPCHSGeometry(void *pBackendData,
2005	PCVDGEOMETRY pPCHSGeometry)
2006	{
2007	LogFlowFunc(("pBackendData=%#p pPCHSGeometry=%#p PCHS=%u/%u/%u\n", pBackendData, pPCHSGeometry, pPCHSGeometry->cCylinders, pPCHSGeometry->cHeads, pPCHSGeometry->cSectors));
2008	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2009	int rc;
2010
2011	AssertPtr(pImage);
2012
2013	if (pImage)
2014	{
2015	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2016	{
2017	rc = VERR_VD_IMAGE_READ_ONLY;
2018	goto out;
2019	}
2020
2021	pImage->PCHSGeometry = *pPCHSGeometry;
2022	rc = VINF_SUCCESS;
2023	}
2024	else
2025	rc = VERR_VD_NOT_OPENED;
2026
2027	out:
2028	LogFlowFunc(("returns %Rrc\n", rc));
2029	return rc;
2030	}
2031
2032	/** @copydoc VBOXHDDBACKEND::pfnGetLCHSGeometry */
2033	static int qcowGetLCHSGeometry(void *pBackendData,
2034	PVDGEOMETRY pLCHSGeometry)
2035	{
2036	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p\n", pBackendData, pLCHSGeometry));
2037	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2038	int rc;
2039
2040	AssertPtr(pImage);
2041
2042	if (pImage)
2043	{
2044	if (pImage->LCHSGeometry.cCylinders)
2045	{
2046	*pLCHSGeometry = pImage->LCHSGeometry;
2047	rc = VINF_SUCCESS;
2048	}
2049	else
2050	rc = VERR_VD_GEOMETRY_NOT_SET;
2051	}
2052	else
2053	rc = VERR_VD_NOT_OPENED;
2054
2055	LogFlowFunc(("returns %Rrc (LCHS=%u/%u/%u)\n", rc, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2056	return rc;
2057	}
2058
2059	/** @copydoc VBOXHDDBACKEND::pfnSetLCHSGeometry */
2060	static int qcowSetLCHSGeometry(void *pBackendData,
2061	PCVDGEOMETRY pLCHSGeometry)
2062	{
2063	LogFlowFunc(("pBackendData=%#p pLCHSGeometry=%#p LCHS=%u/%u/%u\n", pBackendData, pLCHSGeometry, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
2064	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2065	int rc;
2066
2067	AssertPtr(pImage);
2068
2069	if (pImage)
2070	{
2071	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2072	{
2073	rc = VERR_VD_IMAGE_READ_ONLY;
2074	goto out;
2075	}
2076
2077	pImage->LCHSGeometry = *pLCHSGeometry;
2078	rc = VINF_SUCCESS;
2079	}
2080	else
2081	rc = VERR_VD_NOT_OPENED;
2082
2083	out:
2084	LogFlowFunc(("returns %Rrc\n", rc));
2085	return rc;
2086	}
2087
2088	/** @copydoc VBOXHDDBACKEND::pfnGetImageFlags */
2089	static unsigned qcowGetImageFlags(void *pBackendData)
2090	{
2091	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2092	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2093	unsigned uImageFlags;
2094
2095	AssertPtr(pImage);
2096
2097	if (pImage)
2098	uImageFlags = pImage->uImageFlags;
2099	else
2100	uImageFlags = 0;
2101
2102	LogFlowFunc(("returns %#x\n", uImageFlags));
2103	return uImageFlags;
2104	}
2105
2106	/** @copydoc VBOXHDDBACKEND::pfnGetOpenFlags */
2107	static unsigned qcowGetOpenFlags(void *pBackendData)
2108	{
2109	LogFlowFunc(("pBackendData=%#p\n", pBackendData));
2110	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2111	unsigned uOpenFlags;
2112
2113	AssertPtr(pImage);
2114
2115	if (pImage)
2116	uOpenFlags = pImage->uOpenFlags;
2117	else
2118	uOpenFlags = 0;
2119
2120	LogFlowFunc(("returns %#x\n", uOpenFlags));
2121	return uOpenFlags;
2122	}
2123
2124	/** @copydoc VBOXHDDBACKEND::pfnSetOpenFlags */
2125	static int qcowSetOpenFlags(void *pBackendData, unsigned uOpenFlags)
2126	{
2127	LogFlowFunc(("pBackendData=%#p\n uOpenFlags=%#x", pBackendData, uOpenFlags));
2128	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2129	int rc;
2130
2131	/* Image must be opened and the new flags must be valid. */
2132	if (!pImage \|\| (uOpenFlags & ~( VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_INFO
2133	\| VD_OPEN_FLAGS_ASYNC_IO \| VD_OPEN_FLAGS_SKIP_CONSISTENCY_CHECKS)))
2134	{
2135	rc = VERR_INVALID_PARAMETER;
2136	goto out;
2137	}
2138
2139	/* Implement this operation via reopening the image. */
2140	rc = qcowFreeImage(pImage, false);
2141	if (RT_FAILURE(rc))
2142	goto out;
2143	rc = qcowOpenImage(pImage, uOpenFlags);
2144
2145	out:
2146	LogFlowFunc(("returns %Rrc\n", rc));
2147	return rc;
2148	}
2149
2150	/** @copydoc VBOXHDDBACKEND::pfnGetComment */
2151	static int qcowGetComment(void pBackendData, char pszComment,
2152	size_t cbComment)
2153	{
2154	LogFlowFunc(("pBackendData=%#p pszComment=%#p cbComment=%zu\n", pBackendData, pszComment, cbComment));
2155	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2156	int rc;
2157
2158	AssertPtr(pImage);
2159
2160	if (pImage)
2161	rc = VERR_NOT_SUPPORTED;
2162	else
2163	rc = VERR_VD_NOT_OPENED;
2164
2165	LogFlowFunc(("returns %Rrc comment='%s'\n", rc, pszComment));
2166	return rc;
2167	}
2168
2169	/** @copydoc VBOXHDDBACKEND::pfnSetComment */
2170	static int qcowSetComment(void pBackendData, const char pszComment)
2171	{
2172	LogFlowFunc(("pBackendData=%#p pszComment=\"%s\"\n", pBackendData, pszComment));
2173	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2174	int rc;
2175
2176	AssertPtr(pImage);
2177
2178	if (pImage)
2179	{
2180	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2181	rc = VERR_VD_IMAGE_READ_ONLY;
2182	else
2183	rc = VERR_NOT_SUPPORTED;
2184	}
2185	else
2186	rc = VERR_VD_NOT_OPENED;
2187
2188	LogFlowFunc(("returns %Rrc\n", rc));
2189	return rc;
2190	}
2191
2192	/** @copydoc VBOXHDDBACKEND::pfnGetUuid */
2193	static int qcowGetUuid(void *pBackendData, PRTUUID pUuid)
2194	{
2195	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2196	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2197	int rc;
2198
2199	AssertPtr(pImage);
2200
2201	if (pImage)
2202	rc = VERR_NOT_SUPPORTED;
2203	else
2204	rc = VERR_VD_NOT_OPENED;
2205
2206	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2207	return rc;
2208	}
2209
2210	/** @copydoc VBOXHDDBACKEND::pfnSetUuid */
2211	static int qcowSetUuid(void *pBackendData, PCRTUUID pUuid)
2212	{
2213	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2214	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2215	int rc;
2216
2217	LogFlowFunc(("%RTuuid\n", pUuid));
2218	AssertPtr(pImage);
2219
2220	if (pImage)
2221	{
2222	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2223	rc = VERR_NOT_SUPPORTED;
2224	else
2225	rc = VERR_VD_IMAGE_READ_ONLY;
2226	}
2227	else
2228	rc = VERR_VD_NOT_OPENED;
2229
2230	LogFlowFunc(("returns %Rrc\n", rc));
2231	return rc;
2232	}
2233
2234	/** @copydoc VBOXHDDBACKEND::pfnGetModificationUuid */
2235	static int qcowGetModificationUuid(void *pBackendData, PRTUUID pUuid)
2236	{
2237	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2238	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2239	int rc;
2240
2241	AssertPtr(pImage);
2242
2243	if (pImage)
2244	rc = VERR_NOT_SUPPORTED;
2245	else
2246	rc = VERR_VD_NOT_OPENED;
2247
2248	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2249	return rc;
2250	}
2251
2252	/** @copydoc VBOXHDDBACKEND::pfnSetModificationUuid */
2253	static int qcowSetModificationUuid(void *pBackendData, PCRTUUID pUuid)
2254	{
2255	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2256	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2257	int rc;
2258
2259	AssertPtr(pImage);
2260
2261	if (pImage)
2262	{
2263	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2264	rc = VERR_NOT_SUPPORTED;
2265	else
2266	rc = VERR_VD_IMAGE_READ_ONLY;
2267	}
2268	else
2269	rc = VERR_VD_NOT_OPENED;
2270
2271	LogFlowFunc(("returns %Rrc\n", rc));
2272	return rc;
2273	}
2274
2275	/** @copydoc VBOXHDDBACKEND::pfnGetParentUuid */
2276	static int qcowGetParentUuid(void *pBackendData, PRTUUID pUuid)
2277	{
2278	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2279	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2280	int rc;
2281
2282	AssertPtr(pImage);
2283
2284	if (pImage)
2285	rc = VERR_NOT_SUPPORTED;
2286	else
2287	rc = VERR_VD_NOT_OPENED;
2288
2289	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2290	return rc;
2291	}
2292
2293	/** @copydoc VBOXHDDBACKEND::pfnSetParentUuid */
2294	static int qcowSetParentUuid(void *pBackendData, PCRTUUID pUuid)
2295	{
2296	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2297	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2298	int rc;
2299
2300	AssertPtr(pImage);
2301
2302	if (pImage)
2303	{
2304	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2305	rc = VERR_NOT_SUPPORTED;
2306	else
2307	rc = VERR_VD_IMAGE_READ_ONLY;
2308	}
2309	else
2310	rc = VERR_VD_NOT_OPENED;
2311
2312	LogFlowFunc(("returns %Rrc\n", rc));
2313	return rc;
2314	}
2315
2316	/** @copydoc VBOXHDDBACKEND::pfnGetParentModificationUuid */
2317	static int qcowGetParentModificationUuid(void *pBackendData, PRTUUID pUuid)
2318	{
2319	LogFlowFunc(("pBackendData=%#p pUuid=%#p\n", pBackendData, pUuid));
2320	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2321	int rc;
2322
2323	AssertPtr(pImage);
2324
2325	if (pImage)
2326	rc = VERR_NOT_SUPPORTED;
2327	else
2328	rc = VERR_VD_NOT_OPENED;
2329
2330	LogFlowFunc(("returns %Rrc (%RTuuid)\n", rc, pUuid));
2331	return rc;
2332	}
2333
2334	/** @copydoc VBOXHDDBACKEND::pfnSetParentModificationUuid */
2335	static int qcowSetParentModificationUuid(void *pBackendData, PCRTUUID pUuid)
2336	{
2337	LogFlowFunc(("pBackendData=%#p Uuid=%RTuuid\n", pBackendData, pUuid));
2338	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2339	int rc;
2340
2341	AssertPtr(pImage);
2342
2343	if (pImage)
2344	{
2345	if (!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY))
2346	rc = VERR_NOT_SUPPORTED;
2347	else
2348	rc = VERR_VD_IMAGE_READ_ONLY;
2349	}
2350	else
2351	rc = VERR_VD_NOT_OPENED;
2352
2353	LogFlowFunc(("returns %Rrc\n", rc));
2354	return rc;
2355	}
2356
2357	/** @copydoc VBOXHDDBACKEND::pfnDump */
2358	static void qcowDump(void *pBackendData)
2359	{
2360	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2361
2362	AssertPtr(pImage);
2363	if (pImage)
2364	{
2365	vdIfErrorMessage(pImage->pIfError, "Header: Geometry PCHS=%u/%u/%u LCHS=%u/%u/%u cSector=%llu\n",
2366	pImage->PCHSGeometry.cCylinders, pImage->PCHSGeometry.cHeads, pImage->PCHSGeometry.cSectors,
2367	pImage->LCHSGeometry.cCylinders, pImage->LCHSGeometry.cHeads, pImage->LCHSGeometry.cSectors,
2368	pImage->cbSize / 512);
2369	}
2370	}
2371
2372	/** @copydoc VBOXHDDBACKEND::pfnGetParentFilename */
2373	static int qcowGetParentFilename(void pBackendData, char *ppszParentFilename)
2374	{
2375	int rc = VINF_SUCCESS;
2376	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2377
2378	AssertPtr(pImage);
2379	if (pImage)
2380	if (pImage->pszFilename)
2381	*ppszParentFilename = RTStrDup(pImage->pszBackingFilename);
2382	else
2383	rc = VERR_NOT_SUPPORTED;
2384	else
2385	rc = VERR_VD_NOT_OPENED;
2386
2387	LogFlowFunc(("returns %Rrc\n", rc));
2388	return rc;
2389	}
2390
2391	/** @copydoc VBOXHDDBACKEND::pfnSetParentFilename */
2392	static int qcowSetParentFilename(void pBackendData, const char pszParentFilename)
2393	{
2394	int rc = VINF_SUCCESS;
2395	PQCOWIMAGE pImage = (PQCOWIMAGE)pBackendData;
2396
2397	AssertPtr(pImage);
2398	if (pImage)
2399	{
2400	if (pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY)
2401	rc = VERR_VD_IMAGE_READ_ONLY;
2402	else if ( pImage->pszBackingFilename
2403	&& (strlen(pszParentFilename) > pImage->cbBackingFilename))
2404	rc = VERR_NOT_SUPPORTED; /* The new filename is longer than the old one. */
2405	else
2406	{
2407	if (pImage->pszBackingFilename)
2408	RTStrFree(pImage->pszBackingFilename);
2409	pImage->pszBackingFilename = RTStrDup(pszParentFilename);
2410	if (!pImage->pszBackingFilename)
2411	rc = VERR_NO_MEMORY;
2412	else
2413	{
2414	if (!pImage->offBackingFilename)
2415	{
2416	/* Allocate new cluster. */
2417	uint64_t offData = qcowClusterAllocate(pImage, 1);
2418
2419	Assert((offData & UINT32_MAX) == offData);
2420	pImage->offBackingFilename = (uint32_t)offData;
2421	pImage->cbBackingFilename = strlen(pszParentFilename);
2422	rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage,
2423	offData + pImage->cbCluster);
2424	}
2425
2426	if (RT_SUCCESS(rc))
2427	rc = vdIfIoIntFileWriteSync(pImage->pIfIo, pImage->pStorage,
2428	pImage->offBackingFilename,
2429	pImage->pszBackingFilename,
2430	strlen(pImage->pszBackingFilename));
2431	}
2432	}
2433	}
2434	else
2435	rc = VERR_VD_NOT_OPENED;
2436
2437	LogFlowFunc(("returns %Rrc\n", rc));
2438	return rc;
2439	}
2440
2441
2442
2443	VBOXHDDBACKEND g_QCowBackend =
2444	{
2445	/* pszBackendName */
2446	"QCOW",
2447	/* cbSize */
2448	sizeof(VBOXHDDBACKEND),
2449	/* uBackendCaps */
2450	VD_CAP_FILE \| VD_CAP_VFS \| VD_CAP_CREATE_DYNAMIC \| VD_CAP_DIFF \| VD_CAP_ASYNC,
2451	/* paFileExtensions */
2452	s_aQCowFileExtensions,
2453	/* paConfigInfo */
2454	NULL,
2455	/* hPlugin */
2456	NIL_RTLDRMOD,
2457	/* pfnCheckIfValid */
2458	qcowCheckIfValid,
2459	/* pfnOpen */
2460	qcowOpen,
2461	/* pfnCreate */
2462	qcowCreate,
2463	/* pfnRename */
2464	qcowRename,
2465	/* pfnClose */
2466	qcowClose,
2467	/* pfnRead */
2468	qcowRead,
2469	/* pfnWrite */
2470	qcowWrite,
2471	/* pfnFlush */
2472	qcowFlush,
2473	/* pfnDiscard */
2474	NULL,
2475	/* pfnGetVersion */
2476	qcowGetVersion,
2477	/* pfnGetSize */
2478	qcowGetSize,
2479	/* pfnGetFileSize */
2480	qcowGetFileSize,
2481	/* pfnGetPCHSGeometry */
2482	qcowGetPCHSGeometry,
2483	/* pfnSetPCHSGeometry */
2484	qcowSetPCHSGeometry,
2485	/* pfnGetLCHSGeometry */
2486	qcowGetLCHSGeometry,
2487	/* pfnSetLCHSGeometry */
2488	qcowSetLCHSGeometry,
2489	/* pfnGetImageFlags */
2490	qcowGetImageFlags,
2491	/* pfnGetOpenFlags */
2492	qcowGetOpenFlags,
2493	/* pfnSetOpenFlags */
2494	qcowSetOpenFlags,
2495	/* pfnGetComment */
2496	qcowGetComment,
2497	/* pfnSetComment */
2498	qcowSetComment,
2499	/* pfnGetUuid */
2500	qcowGetUuid,
2501	/* pfnSetUuid */
2502	qcowSetUuid,
2503	/* pfnGetModificationUuid */
2504	qcowGetModificationUuid,
2505	/* pfnSetModificationUuid */
2506	qcowSetModificationUuid,
2507	/* pfnGetParentUuid */
2508	qcowGetParentUuid,
2509	/* pfnSetParentUuid */
2510	qcowSetParentUuid,
2511	/* pfnGetParentModificationUuid */
2512	qcowGetParentModificationUuid,
2513	/* pfnSetParentModificationUuid */
2514	qcowSetParentModificationUuid,
2515	/* pfnDump */
2516	qcowDump,
2517	/* pfnGetTimeStamp */
2518	NULL,
2519	/* pfnGetParentTimeStamp */
2520	NULL,
2521	/* pfnSetParentTimeStamp */
2522	NULL,
2523	/* pfnGetParentFilename */
2524	qcowGetParentFilename,
2525	/* pfnSetParentFilename */
2526	qcowSetParentFilename,
2527	/* pfnComposeLocation */
2528	genericFileComposeLocation,
2529	/* pfnComposeName */
2530	genericFileComposeName,
2531	/* pfnCompact */
2532	NULL,
2533	/* pfnResize */
2534	NULL,
2535	/* pfnRepair */
2536	NULL
2537	};

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source: vbox/trunk/src/VBox/Storage/QCOW.cpp@ 44902

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