VDICore.h@ 34891

Last change on this file since 34891 was 33567, checked in by vboxsync, 14 years ago
VD: Move the generic virtual disk framework + backends to src/VBox/Storage and rename the files to get rid of the HDD part because it supports floppy and DVD images too
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File size: 20.9 KB

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1	/* $Id: VDICore.h 33567 2010-10-28 15:37:21Z vboxsync $ */
2	/** @file
3	* Virtual Disk Image (VDI), Core Code Header (internal).
4	*/
5
6	/*
7	* Copyright (C) 2006-2010 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	#ifndef __VDICore_h__
19
20
21	/*******************************************************************************
22	* Header Files *
23	*******************************************************************************/
24	#include <VBox/vd.h>
25	#ifndef VBOX_VDICORE_VD
26	#include <VBox/pdm.h>
27	#endif /* !VBOX_VDICORE_VD */
28	#include <VBox/mm.h>
29	#include <VBox/err.h>
30
31	#include <VBox/log.h>
32	#include <iprt/alloc.h>
33	#include <iprt/assert.h>
34	#include <iprt/uuid.h>
35	#include <iprt/string.h>
36	#include <iprt/asm.h>
37
38
39	/*******************************************************************************
40	* Constants And Macros, Structures and Typedefs *
41	*******************************************************************************/
42
43	/** Image info, not handled anyhow.
44	* Must be less than 64 bytes in length, including the trailing 0.
45	*/
46	#define VDI_IMAGE_FILE_INFO "<<< Oracle VM VirtualBox Disk Image >>>\n"
47
48	/** The Sector size.
49	* Currently we support only 512 bytes sectors.
50	*/
51	#define VDI_GEOMETRY_SECTOR_SIZE (512)
52	/** 512 = 2^^9 */
53	#define VDI_GEOMETRY_SECTOR_SHIFT (9)
54
55	/**
56	* Harddisk geometry.
57	*/
58	#pragma pack(1)
59	typedef struct VDIDISKGEOMETRY
60	{
61	/** Cylinders. */
62	uint32_t cCylinders;
63	/** Heads. */
64	uint32_t cHeads;
65	/** Sectors per track. */
66	uint32_t cSectors;
67	/** Sector size. (bytes per sector) */
68	uint32_t cbSector;
69	} VDIDISKGEOMETRY, *PVDIDISKGEOMETRY;
70	#pragma pack()
71
72	/** Image signature. */
73	#define VDI_IMAGE_SIGNATURE (0xbeda107f)
74
75	/**
76	* Pre-Header to be stored in image file - used for version control.
77	*/
78	#pragma pack(1)
79	typedef struct VDIPREHEADER
80	{
81	/** Just text info about image type, for eyes only. */
82	char szFileInfo[64];
83	/** The image signature (VDI_IMAGE_SIGNATURE). */
84	uint32_t u32Signature;
85	/** The image version (VDI_IMAGE_VERSION). */
86	uint32_t u32Version;
87	} VDIPREHEADER, *PVDIPREHEADER;
88	#pragma pack()
89
90	/**
91	* Size of szComment field of HDD image header.
92	*/
93	#define VDI_IMAGE_COMMENT_SIZE 256
94
95	/**
96	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 0.
97	* Prepended by VDIPREHEADER.
98	*/
99	#pragma pack(1)
100	typedef struct VDIHEADER0
101	{
102	/** The image type (VDI_IMAGE_TYPE_). /
103	uint32_t u32Type;
104	/** Image flags (VDI_IMAGE_FLAGS_). /
105	uint32_t fFlags;
106	/** Image comment. (UTF-8) */
107	char szComment[VDI_IMAGE_COMMENT_SIZE];
108	/** Legacy image geometry (previous code stored PCHS there). */
109	VDIDISKGEOMETRY LegacyGeometry;
110	/** Size of disk (in bytes). */
111	uint64_t cbDisk;
112	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) */
113	uint32_t cbBlock;
114	/** Number of blocks. */
115	uint32_t cBlocks;
116	/** Number of allocated blocks. */
117	uint32_t cBlocksAllocated;
118	/** UUID of image. */
119	RTUUID uuidCreate;
120	/** UUID of image's last modification. */
121	RTUUID uuidModify;
122	/** Only for secondary images - UUID of primary image. */
123	RTUUID uuidLinkage;
124	} VDIHEADER0, *PVDIHEADER0;
125	#pragma pack()
126
127	/**
128	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 1,
129	* VDI_IMAGE_VERSION_MINOR = 1. Prepended by VDIPREHEADER.
130	*/
131	#pragma pack(1)
132	typedef struct VDIHEADER1
133	{
134	/** Size of this structure in bytes. */
135	uint32_t cbHeader;
136	/** The image type (VDI_IMAGE_TYPE_). /
137	uint32_t u32Type;
138	/** Image flags (VDI_IMAGE_FLAGS_). /
139	uint32_t fFlags;
140	/** Image comment. (UTF-8) */
141	char szComment[VDI_IMAGE_COMMENT_SIZE];
142	/** Offset of Blocks array from the beginning of image file.
143	* Should be sector-aligned for HDD access optimization. */
144	uint32_t offBlocks;
145	/** Offset of image data from the beginning of image file.
146	* Should be sector-aligned for HDD access optimization. */
147	uint32_t offData;
148	/** Legacy image geometry (previous code stored PCHS there). */
149	VDIDISKGEOMETRY LegacyGeometry;
150	/** Was BIOS HDD translation mode, now unused. */
151	uint32_t u32Dummy;
152	/** Size of disk (in bytes). */
153	uint64_t cbDisk;
154	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) Should be a power of 2! */
155	uint32_t cbBlock;
156	/** Size of additional service information of every data block.
157	* Prepended before block data. May be 0.
158	* Should be a power of 2 and sector-aligned for optimization reasons. */
159	uint32_t cbBlockExtra;
160	/** Number of blocks. */
161	uint32_t cBlocks;
162	/** Number of allocated blocks. */
163	uint32_t cBlocksAllocated;
164	/** UUID of image. */
165	RTUUID uuidCreate;
166	/** UUID of image's last modification. */
167	RTUUID uuidModify;
168	/** Only for secondary images - UUID of previous image. */
169	RTUUID uuidLinkage;
170	/** Only for secondary images - UUID of previous image's last modification. */
171	RTUUID uuidParentModify;
172	} VDIHEADER1, *PVDIHEADER1;
173	#pragma pack()
174
175	/**
176	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 1,
177	* VDI_IMAGE_VERSION_MINOR = 1, the slightly changed variant necessary as the
178	* old released code doesn't support changing the minor version at all.
179	*/
180	#pragma pack(1)
181	typedef struct VDIHEADER1PLUS
182	{
183	/** Size of this structure in bytes. */
184	uint32_t cbHeader;
185	/** The image type (VDI_IMAGE_TYPE_). /
186	uint32_t u32Type;
187	/** Image flags (VDI_IMAGE_FLAGS_). /
188	uint32_t fFlags;
189	/** Image comment. (UTF-8) */
190	char szComment[VDI_IMAGE_COMMENT_SIZE];
191	/** Offset of blocks array from the beginning of image file.
192	* Should be sector-aligned for HDD access optimization. */
193	uint32_t offBlocks;
194	/** Offset of image data from the beginning of image file.
195	* Should be sector-aligned for HDD access optimization. */
196	uint32_t offData;
197	/** Legacy image geometry (previous code stored PCHS there). */
198	VDIDISKGEOMETRY LegacyGeometry;
199	/** Was BIOS HDD translation mode, now unused. */
200	uint32_t u32Dummy;
201	/** Size of disk (in bytes). */
202	uint64_t cbDisk;
203	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) Should be a power of 2! */
204	uint32_t cbBlock;
205	/** Size of additional service information of every data block.
206	* Prepended before block data. May be 0.
207	* Should be a power of 2 and sector-aligned for optimization reasons. */
208	uint32_t cbBlockExtra;
209	/** Number of blocks. */
210	uint32_t cBlocks;
211	/** Number of allocated blocks. */
212	uint32_t cBlocksAllocated;
213	/** UUID of image. */
214	RTUUID uuidCreate;
215	/** UUID of image's last modification. */
216	RTUUID uuidModify;
217	/** Only for secondary images - UUID of previous image. */
218	RTUUID uuidLinkage;
219	/** Only for secondary images - UUID of previous image's last modification. */
220	RTUUID uuidParentModify;
221	/** LCHS image geometry (new field in VDI1.2 version. */
222	VDIDISKGEOMETRY LCHSGeometry;
223	} VDIHEADER1PLUS, *PVDIHEADER1PLUS;
224	#pragma pack()
225
226	/**
227	* Header structure for all versions.
228	*/
229	typedef struct VDIHEADER
230	{
231	unsigned uVersion;
232	union
233	{
234	VDIHEADER0 v0;
235	VDIHEADER1 v1;
236	VDIHEADER1PLUS v1plus;
237	} u;
238	} VDIHEADER, *PVDIHEADER;
239
240	/**
241	* File alignment boundary for both the block array and data area. Should be
242	* at least the size of a physical sector on disk for performance reasons.
243	* With the growing market share of disks with 4K sectors this needs to be
244	* bumped, and maybe again later. */
245	#define VDI_DATA_ALIGN _4K
246
247	/** Block 'pointer'. */
248	typedef uint32_t VDIIMAGEBLOCKPOINTER;
249	/** Pointer to a block 'pointer'. */
250	typedef VDIIMAGEBLOCKPOINTER *PVDIIMAGEBLOCKPOINTER;
251
252	/**
253	* Block marked as free is not allocated in image file, read from this
254	* block may returns any random data.
255	*/
256	#define VDI_IMAGE_BLOCK_FREE ((VDIIMAGEBLOCKPOINTER)~0)
257
258	/**
259	* Block marked as zero is not allocated in image file, read from this
260	* block returns zeroes.
261	*/
262	#define VDI_IMAGE_BLOCK_ZERO ((VDIIMAGEBLOCKPOINTER)~1)
263
264	/**
265	* Block 'pointer' >= VDI_IMAGE_BLOCK_UNALLOCATED indicates block is not
266	* allocated in image file.
267	*/
268	#define VDI_IMAGE_BLOCK_UNALLOCATED (VDI_IMAGE_BLOCK_ZERO)
269	#define IS_VDI_IMAGE_BLOCK_ALLOCATED(bp) (bp < VDI_IMAGE_BLOCK_UNALLOCATED)
270
271	#define GET_MAJOR_HEADER_VERSION(ph) (VDI_GET_VERSION_MAJOR((ph)->uVersion))
272	#define GET_MINOR_HEADER_VERSION(ph) (VDI_GET_VERSION_MINOR((ph)->uVersion))
273
274	#ifdef VBOX_VDICORE_VD
275	/** @name VDI image types
276	* @{ */
277	typedef enum VDIIMAGETYPE
278	{
279	/** Normal dynamically growing base image file. */
280	VDI_IMAGE_TYPE_NORMAL = 1,
281	/** Preallocated base image file of a fixed size. */
282	VDI_IMAGE_TYPE_FIXED,
283	/** Dynamically growing image file for undo/commit changes support. */
284	VDI_IMAGE_TYPE_UNDO,
285	/** Dynamically growing image file for differencing support. */
286	VDI_IMAGE_TYPE_DIFF,
287
288	/** First valid image type value. */
289	VDI_IMAGE_TYPE_FIRST = VDI_IMAGE_TYPE_NORMAL,
290	/** Last valid image type value. */
291	VDI_IMAGE_TYPE_LAST = VDI_IMAGE_TYPE_DIFF
292	} VDIIMAGETYPE;
293	/** Pointer to VDI image type. */
294	typedef VDIIMAGETYPE *PVDIIMAGETYPE;
295	/** @} */
296	#endif /* VBOX_VDICORE_VD */
297
298	/*******************************************************************************
299	* Internal Functions for header access *
300	*******************************************************************************/
301	DECLINLINE(VDIIMAGETYPE) getImageType(PVDIHEADER ph)
302	{
303	switch (GET_MAJOR_HEADER_VERSION(ph))
304	{
305	case 0: return (VDIIMAGETYPE)ph->u.v0.u32Type;
306	case 1: return (VDIIMAGETYPE)ph->u.v1.u32Type;
307	}
308	AssertFailed();
309	return (VDIIMAGETYPE)0;
310	}
311
312	#ifdef VBOX_VDICORE_VD
313	DECLINLINE(unsigned) getImageFlags(PVDIHEADER ph)
314	{
315	switch (GET_MAJOR_HEADER_VERSION(ph))
316	{
317	case 0:
318	/* VDI image flag conversion to VD image flags. */
319	return ph->u.v0.fFlags << 8;
320	case 1:
321	/* VDI image flag conversion to VD image flags. */
322	return ph->u.v1.fFlags << 8;
323	}
324	AssertFailed();
325	return 0;
326	}
327	#else /* !VBOX_VDICORE_VD */
328	DECLINLINE(unsigned) getImageFlags(PVDIHEADER ph)
329	{
330	switch (GET_MAJOR_HEADER_VERSION(ph))
331	{
332	case 0: return ph->u.v0.fFlags;
333	case 1: return ph->u.v1.fFlags;
334	}
335	AssertFailed();
336	return 0;
337	}
338	#endif /* !VBOX_VDICORE_VD */
339
340	DECLINLINE(char *) getImageComment(PVDIHEADER ph)
341	{
342	switch (GET_MAJOR_HEADER_VERSION(ph))
343	{
344	case 0: return &ph->u.v0.szComment[0];
345	case 1: return &ph->u.v1.szComment[0];
346	}
347	AssertFailed();
348	return NULL;
349	}
350
351	DECLINLINE(unsigned) getImageBlocksOffset(PVDIHEADER ph)
352	{
353	switch (GET_MAJOR_HEADER_VERSION(ph))
354	{
355	case 0: return (sizeof(VDIPREHEADER) + sizeof(VDIHEADER0));
356	case 1: return ph->u.v1.offBlocks;
357	}
358	AssertFailed();
359	return 0;
360	}
361
362	DECLINLINE(uint32_t) getImageDataOffset(PVDIHEADER ph)
363	{
364	switch (GET_MAJOR_HEADER_VERSION(ph))
365	{
366	case 0: return sizeof(VDIPREHEADER) + sizeof(VDIHEADER0) + \
367	(ph->u.v0.cBlocks * sizeof(VDIIMAGEBLOCKPOINTER));
368	case 1: return ph->u.v1.offData;
369	}
370	AssertFailed();
371	return 0;
372	}
373
374	DECLINLINE(void) setImageDataOffset(PVDIHEADER ph, uint32_t offData)
375	{
376	switch (GET_MAJOR_HEADER_VERSION(ph))
377	{
378	case 0: return;
379	case 1: ph->u.v1.offData = offData; return;
380	}
381	AssertFailed();
382	}
383
384	DECLINLINE(PVDIDISKGEOMETRY) getImageLCHSGeometry(PVDIHEADER ph)
385	{
386	switch (GET_MAJOR_HEADER_VERSION(ph))
387	{
388	case 0: return NULL;
389	case 1:
390	switch (GET_MINOR_HEADER_VERSION(ph))
391	{
392	case 1:
393	if (ph->u.v1.cbHeader < sizeof(ph->u.v1plus))
394	return NULL;
395	else
396	return &ph->u.v1plus.LCHSGeometry;
397	}
398	}
399	AssertFailed();
400	return NULL;
401	}
402
403	DECLINLINE(uint64_t) getImageDiskSize(PVDIHEADER ph)
404	{
405	switch (GET_MAJOR_HEADER_VERSION(ph))
406	{
407	case 0: return ph->u.v0.cbDisk;
408	case 1: return ph->u.v1.cbDisk;
409	}
410	AssertFailed();
411	return 0;
412	}
413
414	DECLINLINE(void) setImageDiskSize(PVDIHEADER ph, uint64_t cbDisk)
415	{
416	switch (GET_MAJOR_HEADER_VERSION(ph))
417	{
418	case 0: ph->u.v0.cbDisk = cbDisk; return;
419	case 1: ph->u.v1.cbDisk = cbDisk; return;
420	}
421	AssertFailed();
422	}
423
424	DECLINLINE(unsigned) getImageBlockSize(PVDIHEADER ph)
425	{
426	switch (GET_MAJOR_HEADER_VERSION(ph))
427	{
428	case 0: return ph->u.v0.cbBlock;
429	case 1: return ph->u.v1.cbBlock;
430	}
431	AssertFailed();
432	return 0;
433	}
434
435	DECLINLINE(unsigned) getImageExtraBlockSize(PVDIHEADER ph)
436	{
437	switch (GET_MAJOR_HEADER_VERSION(ph))
438	{
439	case 0: return 0;
440	case 1: return ph->u.v1.cbBlockExtra;
441	}
442	AssertFailed();
443	return 0;
444	}
445
446	DECLINLINE(unsigned) getImageBlocks(PVDIHEADER ph)
447	{
448	switch (GET_MAJOR_HEADER_VERSION(ph))
449	{
450	case 0: return ph->u.v0.cBlocks;
451	case 1: return ph->u.v1.cBlocks;
452	}
453	AssertFailed();
454	return 0;
455	}
456
457	DECLINLINE(void) setImageBlocks(PVDIHEADER ph, unsigned cBlocks)
458	{
459	switch (GET_MAJOR_HEADER_VERSION(ph))
460	{
461	case 0: ph->u.v0.cBlocks = cBlocks; return;
462	case 1: ph->u.v1.cBlocks = cBlocks; return;
463	}
464	AssertFailed();
465	}
466
467
468	DECLINLINE(unsigned) getImageBlocksAllocated(PVDIHEADER ph)
469	{
470	switch (GET_MAJOR_HEADER_VERSION(ph))
471	{
472	case 0: return ph->u.v0.cBlocksAllocated;
473	case 1: return ph->u.v1.cBlocksAllocated;
474	}
475	AssertFailed();
476	return 0;
477	}
478
479	DECLINLINE(void) setImageBlocksAllocated(PVDIHEADER ph, unsigned cBlocks)
480	{
481	switch (GET_MAJOR_HEADER_VERSION(ph))
482	{
483	case 0: ph->u.v0.cBlocksAllocated = cBlocks; return;
484	case 1: ph->u.v1.cBlocksAllocated = cBlocks; return;
485	}
486	AssertFailed();
487	}
488
489	DECLINLINE(PRTUUID) getImageCreationUUID(PVDIHEADER ph)
490	{
491	switch (GET_MAJOR_HEADER_VERSION(ph))
492	{
493	case 0: return &ph->u.v0.uuidCreate;
494	case 1: return &ph->u.v1.uuidCreate;
495	}
496	AssertFailed();
497	return NULL;
498	}
499
500	DECLINLINE(PRTUUID) getImageModificationUUID(PVDIHEADER ph)
501	{
502	switch (GET_MAJOR_HEADER_VERSION(ph))
503	{
504	case 0: return &ph->u.v0.uuidModify;
505	case 1: return &ph->u.v1.uuidModify;
506	}
507	AssertFailed();
508	return NULL;
509	}
510
511	DECLINLINE(PRTUUID) getImageParentUUID(PVDIHEADER ph)
512	{
513	switch (GET_MAJOR_HEADER_VERSION(ph))
514	{
515	case 0: return &ph->u.v0.uuidLinkage;
516	case 1: return &ph->u.v1.uuidLinkage;
517	}
518	AssertFailed();
519	return NULL;
520	}
521
522	DECLINLINE(PRTUUID) getImageParentModificationUUID(PVDIHEADER ph)
523	{
524	switch (GET_MAJOR_HEADER_VERSION(ph))
525	{
526	case 1: return &ph->u.v1.uuidParentModify;
527	}
528	AssertFailed();
529	return NULL;
530	}
531
532	#ifndef VBOX_VDICORE_VD
533	/**
534	* Default image block size, may be changed by setBlockSize/getBlockSize.
535	*
536	* Note: for speed reasons block size should be a power of 2 !
537	*/
538	#define VDI_IMAGE_DEFAULT_BLOCK_SIZE _1M
539	#endif /* !VBOX_VDICORE_VD */
540
541	#ifndef VBOX_VDICORE_VD
542	/**
543	* fModified bit flags.
544	*/
545	#define VDI_IMAGE_MODIFIED_FLAG RT_BIT(0)
546	#define VDI_IMAGE_MODIFIED_FIRST RT_BIT(1)
547	#define VDI_IMAGE_MODIFIED_DISABLE_UUID_UPDATE RT_BIT(2)
548	#endif /* !VBOX_VDICORE_VD */
549
550	/**
551	* Image structure
552	*/
553	typedef struct VDIIMAGEDESC
554	{
555	#ifndef VBOX_VDICORE_VD
556	/** Link to parent image descriptor, if any. */
557	struct VDIIMAGEDESC *pPrev;
558	/** Link to child image descriptor, if any. */
559	struct VDIIMAGEDESC *pNext;
560	#endif /* !VBOX_VDICORE_VD */
561	/** Opaque storage handle. */
562	PVDIOSTORAGE pStorage;
563	#ifndef VBOX_VDICORE_VD
564	/** True if the image is operating in readonly mode. */
565	bool fReadOnly;
566	/** Image open flags, VDI_OPEN_FLAGS_. /
567	unsigned fOpen;
568	#else /* VBOX_VDICORE_VD */
569	/** Image open flags, VD_OPEN_FLAGS_. /
570	unsigned uOpenFlags;
571	#endif /* VBOX_VDICORE_VD */
572	/** Image pre-header. */
573	VDIPREHEADER PreHeader;
574	/** Image header. */
575	VDIHEADER Header;
576	/** Pointer to a block array. */
577	PVDIIMAGEBLOCKPOINTER paBlocks;
578	#ifndef VBOX_VDICORE_VD
579	/** fFlags copy from image header, for speed optimization. */
580	unsigned fFlags;
581	#else /* VBOX_VDICORE_VD */
582	/** fFlags copy from image header, for speed optimization. */
583	unsigned uImageFlags;
584	#endif /* VBOX_VDICORE_VD */
585	/** Start offset of block array in image file, here for speed optimization. */
586	unsigned offStartBlocks;
587	/** Start offset of data in image file, here for speed optimization. */
588	unsigned offStartData;
589	/** Block mask for getting the offset into a block from a byte hdd offset. */
590	unsigned uBlockMask;
591	/** Block shift value for converting byte hdd offset into paBlock index. */
592	unsigned uShiftOffset2Index;
593	#ifndef VBOX_VDICORE_VD
594	/** Block shift value for converting block index into offset in image. */
595	unsigned uShiftIndex2Offset;
596	#endif /* !VBOX_VDICORE_VD */
597	/** Offset of data from the beginning of block. */
598	unsigned offStartBlockData;
599	#ifndef VBOX_VDICORE_VD
600	/** Image is modified flags (VDI_IMAGE_MODIFIED). /
601	unsigned fModified;
602	/** Container filename. (UTF-8)
603	* @todo Make this variable length to save a bunch of bytes. (low prio) */
604	char szFilename[RTPATH_MAX];
605	#else /* VBOX_VDICORE_VD */
606	/** Total size of image block (including the extra data). */
607	unsigned cbTotalBlockData;
608	/** Container filename. (UTF-8) */
609	const char *pszFilename;
610	/** Physical geometry of this image (never actually stored). */
611	VDGEOMETRY PCHSGeometry;
612	/** Pointer to the per-disk VD interface list. */
613	PVDINTERFACE pVDIfsDisk;
614	/** Pointer to the per-image VD interface list. */
615	PVDINTERFACE pVDIfsImage;
616	/** Error interface. */
617	PVDINTERFACE pInterfaceError;
618	/** Error interface callback table. */
619	PVDINTERFACEERROR pInterfaceErrorCallbacks;
620	/** I/O interface. */
621	PVDINTERFACE pInterfaceIO;
622	/** I/O interface callbacks. */
623	PVDINTERFACEIOINT pInterfaceIOCallbacks;
624	#endif /* VBOX_VDICORE_VD */
625	} VDIIMAGEDESC, *PVDIIMAGEDESC;
626
627	#ifndef VBOX_VDICORE_VD
628	/**
629	* Default work buffer size, may be changed by setBufferSize() method.
630	*
631	* For best speed performance it must be equal to image block size.
632	*/
633	#define VDIDISK_DEFAULT_BUFFER_SIZE (VDI_IMAGE_DEFAULT_BLOCK_SIZE)
634	#endif /* !VBOX_VDICORE_VD */
635
636	/** VDIDISK Signature. */
637	#define VDIDISK_SIGNATURE (0xbedafeda)
638
639	/**
640	* VBox HDD Container main structure, private part.
641	*/
642	struct VDIDISK
643	{
644	/** Structure signature (VDIDISK_SIGNATURE). */
645	uint32_t u32Signature;
646
647	/** Number of opened images. */
648	unsigned cImages;
649
650	/** Base image. */
651	PVDIIMAGEDESC pBase;
652
653	/** Last opened image in the chain.
654	* The same as pBase if only one image is used or the last opened diff image. */
655	PVDIIMAGEDESC pLast;
656
657	/** Default block size for newly created images. */
658	unsigned cbBlock;
659
660	/** Working buffer size, allocated only while committing data,
661	* copying block from primary image to secondary and saving previously
662	* zero block. Buffer deallocated after operation complete.
663	* @remark For best performance buffer size must be equal to image's
664	* block size, however it may be decreased for memory saving.
665	*/
666	unsigned cbBuf;
667
668	/** Flag whether zero writes should be handled normally or optimized
669	* away if possible. */
670	bool fHonorZeroWrites;
671
672	#ifndef VBOX_VDICORE_VD
673	/** The media interface. */
674	PDMIMEDIA IMedia;
675	/** Pointer to the driver instance. */
676	PPDMDRVINS pDrvIns;
677	#endif /* !VBOX_VDICORE_VD */
678	};
679
680
681	/*******************************************************************************
682	* Internal Functions *
683	*******************************************************************************/
684	RT_C_DECLS_BEGIN
685
686	#ifndef VBOX_VDICORE_VD
687	VBOXDDU_DECL(void) vdiInitVDIDisk(PVDIDISK pDisk);
688	VBOXDDU_DECL(void) VDIFlushImage(PVDIIMAGEDESC pImage);
689	VBOXDDU_DECL(int) vdiChangeImageMode(PVDIIMAGEDESC pImage, bool fReadOnly);
690	#endif /* !VBOX_VDICORE_VD */
691
692	RT_C_DECLS_END
693
694	#endif

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source: vbox/trunk/src/VBox/Storage/VDICore.h@ 34891

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