VDICore.h@ 36214

Last change on this file since 36214 was 35346, checked in by vboxsync, 14 years ago
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1	/* $Id: VDICore.h 35346 2010-12-27 16:13:13Z 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/vmm/pdm.h>
27	#endif
28	#include <VBox/err.h>
29
30	#include <VBox/log.h>
31	#include <iprt/alloc.h>
32	#include <iprt/assert.h>
33	#include <iprt/uuid.h>
34	#include <iprt/string.h>
35	#include <iprt/asm.h>
36
37
38	/*******************************************************************************
39	* Constants And Macros, Structures and Typedefs *
40	*******************************************************************************/
41
42	/** Image info, not handled anyhow.
43	* Must be less than 64 bytes in length, including the trailing 0.
44	*/
45	#define VDI_IMAGE_FILE_INFO "<<< Oracle VM VirtualBox Disk Image >>>\n"
46
47	/** The Sector size.
48	* Currently we support only 512 bytes sectors.
49	*/
50	#define VDI_GEOMETRY_SECTOR_SIZE (512)
51	/** 512 = 2^^9 */
52	#define VDI_GEOMETRY_SECTOR_SHIFT (9)
53
54	/**
55	* Harddisk geometry.
56	*/
57	#pragma pack(1)
58	typedef struct VDIDISKGEOMETRY
59	{
60	/** Cylinders. */
61	uint32_t cCylinders;
62	/** Heads. */
63	uint32_t cHeads;
64	/** Sectors per track. */
65	uint32_t cSectors;
66	/** Sector size. (bytes per sector) */
67	uint32_t cbSector;
68	} VDIDISKGEOMETRY, *PVDIDISKGEOMETRY;
69	#pragma pack()
70
71	/** Image signature. */
72	#define VDI_IMAGE_SIGNATURE (0xbeda107f)
73
74	/**
75	* Pre-Header to be stored in image file - used for version control.
76	*/
77	#pragma pack(1)
78	typedef struct VDIPREHEADER
79	{
80	/** Just text info about image type, for eyes only. */
81	char szFileInfo[64];
82	/** The image signature (VDI_IMAGE_SIGNATURE). */
83	uint32_t u32Signature;
84	/** The image version (VDI_IMAGE_VERSION). */
85	uint32_t u32Version;
86	} VDIPREHEADER, *PVDIPREHEADER;
87	#pragma pack()
88
89	/**
90	* Size of szComment field of HDD image header.
91	*/
92	#define VDI_IMAGE_COMMENT_SIZE 256
93
94	/**
95	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 0.
96	* Prepended by VDIPREHEADER.
97	*/
98	#pragma pack(1)
99	typedef struct VDIHEADER0
100	{
101	/** The image type (VDI_IMAGE_TYPE_). /
102	uint32_t u32Type;
103	/** Image flags (VDI_IMAGE_FLAGS_). /
104	uint32_t fFlags;
105	/** Image comment. (UTF-8) */
106	char szComment[VDI_IMAGE_COMMENT_SIZE];
107	/** Legacy image geometry (previous code stored PCHS there). */
108	VDIDISKGEOMETRY LegacyGeometry;
109	/** Size of disk (in bytes). */
110	uint64_t cbDisk;
111	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) */
112	uint32_t cbBlock;
113	/** Number of blocks. */
114	uint32_t cBlocks;
115	/** Number of allocated blocks. */
116	uint32_t cBlocksAllocated;
117	/** UUID of image. */
118	RTUUID uuidCreate;
119	/** UUID of image's last modification. */
120	RTUUID uuidModify;
121	/** Only for secondary images - UUID of primary image. */
122	RTUUID uuidLinkage;
123	} VDIHEADER0, *PVDIHEADER0;
124	#pragma pack()
125
126	/**
127	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 1,
128	* VDI_IMAGE_VERSION_MINOR = 1. Prepended by VDIPREHEADER.
129	*/
130	#pragma pack(1)
131	typedef struct VDIHEADER1
132	{
133	/** Size of this structure in bytes. */
134	uint32_t cbHeader;
135	/** The image type (VDI_IMAGE_TYPE_). /
136	uint32_t u32Type;
137	/** Image flags (VDI_IMAGE_FLAGS_). /
138	uint32_t fFlags;
139	/** Image comment. (UTF-8) */
140	char szComment[VDI_IMAGE_COMMENT_SIZE];
141	/** Offset of Blocks array from the beginning of image file.
142	* Should be sector-aligned for HDD access optimization. */
143	uint32_t offBlocks;
144	/** Offset of image data from the beginning of image file.
145	* Should be sector-aligned for HDD access optimization. */
146	uint32_t offData;
147	/** Legacy image geometry (previous code stored PCHS there). */
148	VDIDISKGEOMETRY LegacyGeometry;
149	/** Was BIOS HDD translation mode, now unused. */
150	uint32_t u32Dummy;
151	/** Size of disk (in bytes). */
152	uint64_t cbDisk;
153	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) Should be a power of 2! */
154	uint32_t cbBlock;
155	/** Size of additional service information of every data block.
156	* Prepended before block data. May be 0.
157	* Should be a power of 2 and sector-aligned for optimization reasons. */
158	uint32_t cbBlockExtra;
159	/** Number of blocks. */
160	uint32_t cBlocks;
161	/** Number of allocated blocks. */
162	uint32_t cBlocksAllocated;
163	/** UUID of image. */
164	RTUUID uuidCreate;
165	/** UUID of image's last modification. */
166	RTUUID uuidModify;
167	/** Only for secondary images - UUID of previous image. */
168	RTUUID uuidLinkage;
169	/** Only for secondary images - UUID of previous image's last modification. */
170	RTUUID uuidParentModify;
171	} VDIHEADER1, *PVDIHEADER1;
172	#pragma pack()
173
174	/**
175	* Header to be stored in image file, VDI_IMAGE_VERSION_MAJOR = 1,
176	* VDI_IMAGE_VERSION_MINOR = 1, the slightly changed variant necessary as the
177	* old released code doesn't support changing the minor version at all.
178	*/
179	#pragma pack(1)
180	typedef struct VDIHEADER1PLUS
181	{
182	/** Size of this structure in bytes. */
183	uint32_t cbHeader;
184	/** The image type (VDI_IMAGE_TYPE_). /
185	uint32_t u32Type;
186	/** Image flags (VDI_IMAGE_FLAGS_). /
187	uint32_t fFlags;
188	/** Image comment. (UTF-8) */
189	char szComment[VDI_IMAGE_COMMENT_SIZE];
190	/** Offset of blocks array from the beginning of image file.
191	* Should be sector-aligned for HDD access optimization. */
192	uint32_t offBlocks;
193	/** Offset of image data from the beginning of image file.
194	* Should be sector-aligned for HDD access optimization. */
195	uint32_t offData;
196	/** Legacy image geometry (previous code stored PCHS there). */
197	VDIDISKGEOMETRY LegacyGeometry;
198	/** Was BIOS HDD translation mode, now unused. */
199	uint32_t u32Dummy;
200	/** Size of disk (in bytes). */
201	uint64_t cbDisk;
202	/** Block size. (For instance VDI_IMAGE_BLOCK_SIZE.) Should be a power of 2! */
203	uint32_t cbBlock;
204	/** Size of additional service information of every data block.
205	* Prepended before block data. May be 0.
206	* Should be a power of 2 and sector-aligned for optimization reasons. */
207	uint32_t cbBlockExtra;
208	/** Number of blocks. */
209	uint32_t cBlocks;
210	/** Number of allocated blocks. */
211	uint32_t cBlocksAllocated;
212	/** UUID of image. */
213	RTUUID uuidCreate;
214	/** UUID of image's last modification. */
215	RTUUID uuidModify;
216	/** Only for secondary images - UUID of previous image. */
217	RTUUID uuidLinkage;
218	/** Only for secondary images - UUID of previous image's last modification. */
219	RTUUID uuidParentModify;
220	/** LCHS image geometry (new field in VDI1.2 version. */
221	VDIDISKGEOMETRY LCHSGeometry;
222	} VDIHEADER1PLUS, *PVDIHEADER1PLUS;
223	#pragma pack()
224
225	/**
226	* Header structure for all versions.
227	*/
228	typedef struct VDIHEADER
229	{
230	unsigned uVersion;
231	union
232	{
233	VDIHEADER0 v0;
234	VDIHEADER1 v1;
235	VDIHEADER1PLUS v1plus;
236	} u;
237	} VDIHEADER, *PVDIHEADER;
238
239	/**
240	* File alignment boundary for both the block array and data area. Should be
241	* at least the size of a physical sector on disk for performance reasons.
242	* With the growing market share of disks with 4K sectors this needs to be
243	* bumped, and maybe again later. */
244	#define VDI_DATA_ALIGN _4K
245
246	/** Block 'pointer'. */
247	typedef uint32_t VDIIMAGEBLOCKPOINTER;
248	/** Pointer to a block 'pointer'. */
249	typedef VDIIMAGEBLOCKPOINTER *PVDIIMAGEBLOCKPOINTER;
250
251	/**
252	* Block marked as free is not allocated in image file, read from this
253	* block may returns any random data.
254	*/
255	#define VDI_IMAGE_BLOCK_FREE ((VDIIMAGEBLOCKPOINTER)~0)
256
257	/**
258	* Block marked as zero is not allocated in image file, read from this
259	* block returns zeroes.
260	*/
261	#define VDI_IMAGE_BLOCK_ZERO ((VDIIMAGEBLOCKPOINTER)~1)
262
263	/**
264	* Block 'pointer' >= VDI_IMAGE_BLOCK_UNALLOCATED indicates block is not
265	* allocated in image file.
266	*/
267	#define VDI_IMAGE_BLOCK_UNALLOCATED (VDI_IMAGE_BLOCK_ZERO)
268	#define IS_VDI_IMAGE_BLOCK_ALLOCATED(bp) (bp < VDI_IMAGE_BLOCK_UNALLOCATED)
269
270	#define GET_MAJOR_HEADER_VERSION(ph) (VDI_GET_VERSION_MAJOR((ph)->uVersion))
271	#define GET_MINOR_HEADER_VERSION(ph) (VDI_GET_VERSION_MINOR((ph)->uVersion))
272
273	#ifdef VBOX_VDICORE_VD
274	/** @name VDI image types
275	* @{ */
276	typedef enum VDIIMAGETYPE
277	{
278	/** Normal dynamically growing base image file. */
279	VDI_IMAGE_TYPE_NORMAL = 1,
280	/** Preallocated base image file of a fixed size. */
281	VDI_IMAGE_TYPE_FIXED,
282	/** Dynamically growing image file for undo/commit changes support. */
283	VDI_IMAGE_TYPE_UNDO,
284	/** Dynamically growing image file for differencing support. */
285	VDI_IMAGE_TYPE_DIFF,
286
287	/** First valid image type value. */
288	VDI_IMAGE_TYPE_FIRST = VDI_IMAGE_TYPE_NORMAL,
289	/** Last valid image type value. */
290	VDI_IMAGE_TYPE_LAST = VDI_IMAGE_TYPE_DIFF
291	} VDIIMAGETYPE;
292	/** Pointer to VDI image type. */
293	typedef VDIIMAGETYPE *PVDIIMAGETYPE;
294	/** @} */
295	#endif /* VBOX_VDICORE_VD */
296
297	/*******************************************************************************
298	* Internal Functions for header access *
299	*******************************************************************************/
300	DECLINLINE(VDIIMAGETYPE) getImageType(PVDIHEADER ph)
301	{
302	switch (GET_MAJOR_HEADER_VERSION(ph))
303	{
304	case 0: return (VDIIMAGETYPE)ph->u.v0.u32Type;
305	case 1: return (VDIIMAGETYPE)ph->u.v1.u32Type;
306	}
307	AssertFailed();
308	return (VDIIMAGETYPE)0;
309	}
310
311	#ifdef VBOX_VDICORE_VD
312	DECLINLINE(unsigned) getImageFlags(PVDIHEADER ph)
313	{
314	switch (GET_MAJOR_HEADER_VERSION(ph))
315	{
316	case 0:
317	/* VDI image flag conversion to VD image flags. */
318	return ph->u.v0.fFlags << 8;
319	case 1:
320	/* VDI image flag conversion to VD image flags. */
321	return ph->u.v1.fFlags << 8;
322	}
323	AssertFailed();
324	return 0;
325	}
326	#else /* !VBOX_VDICORE_VD */
327	DECLINLINE(unsigned) getImageFlags(PVDIHEADER ph)
328	{
329	switch (GET_MAJOR_HEADER_VERSION(ph))
330	{
331	case 0: return ph->u.v0.fFlags;
332	case 1: return ph->u.v1.fFlags;
333	}
334	AssertFailed();
335	return 0;
336	}
337	#endif /* !VBOX_VDICORE_VD */
338
339	DECLINLINE(char *) getImageComment(PVDIHEADER ph)
340	{
341	switch (GET_MAJOR_HEADER_VERSION(ph))
342	{
343	case 0: return &ph->u.v0.szComment[0];
344	case 1: return &ph->u.v1.szComment[0];
345	}
346	AssertFailed();
347	return NULL;
348	}
349
350	DECLINLINE(unsigned) getImageBlocksOffset(PVDIHEADER ph)
351	{
352	switch (GET_MAJOR_HEADER_VERSION(ph))
353	{
354	case 0: return (sizeof(VDIPREHEADER) + sizeof(VDIHEADER0));
355	case 1: return ph->u.v1.offBlocks;
356	}
357	AssertFailed();
358	return 0;
359	}
360
361	DECLINLINE(uint32_t) getImageDataOffset(PVDIHEADER ph)
362	{
363	switch (GET_MAJOR_HEADER_VERSION(ph))
364	{
365	case 0: return sizeof(VDIPREHEADER) + sizeof(VDIHEADER0) + \
366	(ph->u.v0.cBlocks * sizeof(VDIIMAGEBLOCKPOINTER));
367	case 1: return ph->u.v1.offData;
368	}
369	AssertFailed();
370	return 0;
371	}
372
373	DECLINLINE(void) setImageDataOffset(PVDIHEADER ph, uint32_t offData)
374	{
375	switch (GET_MAJOR_HEADER_VERSION(ph))
376	{
377	case 0: return;
378	case 1: ph->u.v1.offData = offData; return;
379	}
380	AssertFailed();
381	}
382
383	DECLINLINE(PVDIDISKGEOMETRY) getImageLCHSGeometry(PVDIHEADER ph)
384	{
385	switch (GET_MAJOR_HEADER_VERSION(ph))
386	{
387	case 0: return NULL;
388	case 1:
389	switch (GET_MINOR_HEADER_VERSION(ph))
390	{
391	case 1:
392	if (ph->u.v1.cbHeader < sizeof(ph->u.v1plus))
393	return NULL;
394	else
395	return &ph->u.v1plus.LCHSGeometry;
396	}
397	}
398	AssertFailed();
399	return NULL;
400	}
401
402	DECLINLINE(uint64_t) getImageDiskSize(PVDIHEADER ph)
403	{
404	switch (GET_MAJOR_HEADER_VERSION(ph))
405	{
406	case 0: return ph->u.v0.cbDisk;
407	case 1: return ph->u.v1.cbDisk;
408	}
409	AssertFailed();
410	return 0;
411	}
412
413	DECLINLINE(void) setImageDiskSize(PVDIHEADER ph, uint64_t cbDisk)
414	{
415	switch (GET_MAJOR_HEADER_VERSION(ph))
416	{
417	case 0: ph->u.v0.cbDisk = cbDisk; return;
418	case 1: ph->u.v1.cbDisk = cbDisk; return;
419	}
420	AssertFailed();
421	}
422
423	DECLINLINE(unsigned) getImageBlockSize(PVDIHEADER ph)
424	{
425	switch (GET_MAJOR_HEADER_VERSION(ph))
426	{
427	case 0: return ph->u.v0.cbBlock;
428	case 1: return ph->u.v1.cbBlock;
429	}
430	AssertFailed();
431	return 0;
432	}
433
434	DECLINLINE(unsigned) getImageExtraBlockSize(PVDIHEADER ph)
435	{
436	switch (GET_MAJOR_HEADER_VERSION(ph))
437	{
438	case 0: return 0;
439	case 1: return ph->u.v1.cbBlockExtra;
440	}
441	AssertFailed();
442	return 0;
443	}
444
445	DECLINLINE(unsigned) getImageBlocks(PVDIHEADER ph)
446	{
447	switch (GET_MAJOR_HEADER_VERSION(ph))
448	{
449	case 0: return ph->u.v0.cBlocks;
450	case 1: return ph->u.v1.cBlocks;
451	}
452	AssertFailed();
453	return 0;
454	}
455
456	DECLINLINE(void) setImageBlocks(PVDIHEADER ph, unsigned cBlocks)
457	{
458	switch (GET_MAJOR_HEADER_VERSION(ph))
459	{
460	case 0: ph->u.v0.cBlocks = cBlocks; return;
461	case 1: ph->u.v1.cBlocks = cBlocks; return;
462	}
463	AssertFailed();
464	}
465
466
467	DECLINLINE(unsigned) getImageBlocksAllocated(PVDIHEADER ph)
468	{
469	switch (GET_MAJOR_HEADER_VERSION(ph))
470	{
471	case 0: return ph->u.v0.cBlocksAllocated;
472	case 1: return ph->u.v1.cBlocksAllocated;
473	}
474	AssertFailed();
475	return 0;
476	}
477
478	DECLINLINE(void) setImageBlocksAllocated(PVDIHEADER ph, unsigned cBlocks)
479	{
480	switch (GET_MAJOR_HEADER_VERSION(ph))
481	{
482	case 0: ph->u.v0.cBlocksAllocated = cBlocks; return;
483	case 1: ph->u.v1.cBlocksAllocated = cBlocks; return;
484	}
485	AssertFailed();
486	}
487
488	DECLINLINE(PRTUUID) getImageCreationUUID(PVDIHEADER ph)
489	{
490	switch (GET_MAJOR_HEADER_VERSION(ph))
491	{
492	case 0: return &ph->u.v0.uuidCreate;
493	case 1: return &ph->u.v1.uuidCreate;
494	}
495	AssertFailed();
496	return NULL;
497	}
498
499	DECLINLINE(PRTUUID) getImageModificationUUID(PVDIHEADER ph)
500	{
501	switch (GET_MAJOR_HEADER_VERSION(ph))
502	{
503	case 0: return &ph->u.v0.uuidModify;
504	case 1: return &ph->u.v1.uuidModify;
505	}
506	AssertFailed();
507	return NULL;
508	}
509
510	DECLINLINE(PRTUUID) getImageParentUUID(PVDIHEADER ph)
511	{
512	switch (GET_MAJOR_HEADER_VERSION(ph))
513	{
514	case 0: return &ph->u.v0.uuidLinkage;
515	case 1: return &ph->u.v1.uuidLinkage;
516	}
517	AssertFailed();
518	return NULL;
519	}
520
521	DECLINLINE(PRTUUID) getImageParentModificationUUID(PVDIHEADER ph)
522	{
523	switch (GET_MAJOR_HEADER_VERSION(ph))
524	{
525	case 1: return &ph->u.v1.uuidParentModify;
526	}
527	AssertFailed();
528	return NULL;
529	}
530
531	#ifndef VBOX_VDICORE_VD
532	/**
533	* Default image block size, may be changed by setBlockSize/getBlockSize.
534	*
535	* Note: for speed reasons block size should be a power of 2 !
536	*/
537	#define VDI_IMAGE_DEFAULT_BLOCK_SIZE _1M
538	#endif /* !VBOX_VDICORE_VD */
539
540	#ifndef VBOX_VDICORE_VD
541	/**
542	* fModified bit flags.
543	*/
544	#define VDI_IMAGE_MODIFIED_FLAG RT_BIT(0)
545	#define VDI_IMAGE_MODIFIED_FIRST RT_BIT(1)
546	#define VDI_IMAGE_MODIFIED_DISABLE_UUID_UPDATE RT_BIT(2)
547	#endif /* !VBOX_VDICORE_VD */
548
549	/**
550	* Image structure
551	*/
552	typedef struct VDIIMAGEDESC
553	{
554	#ifndef VBOX_VDICORE_VD
555	/** Link to parent image descriptor, if any. */
556	struct VDIIMAGEDESC *pPrev;
557	/** Link to child image descriptor, if any. */
558	struct VDIIMAGEDESC *pNext;
559	#endif /* !VBOX_VDICORE_VD */
560	/** Opaque storage handle. */
561	PVDIOSTORAGE pStorage;
562	#ifndef VBOX_VDICORE_VD
563	/** True if the image is operating in readonly mode. */
564	bool fReadOnly;
565	/** Image open flags, VDI_OPEN_FLAGS_. /
566	unsigned fOpen;
567	#else /* VBOX_VDICORE_VD */
568	/** Image open flags, VD_OPEN_FLAGS_. /
569	unsigned uOpenFlags;
570	#endif /* VBOX_VDICORE_VD */
571	/** Image pre-header. */
572	VDIPREHEADER PreHeader;
573	/** Image header. */
574	VDIHEADER Header;
575	/** Pointer to a block array. */
576	PVDIIMAGEBLOCKPOINTER paBlocks;
577	#ifndef VBOX_VDICORE_VD
578	/** fFlags copy from image header, for speed optimization. */
579	unsigned fFlags;
580	#else /* VBOX_VDICORE_VD */
581	/** fFlags copy from image header, for speed optimization. */
582	unsigned uImageFlags;
583	#endif /* VBOX_VDICORE_VD */
584	/** Start offset of block array in image file, here for speed optimization. */
585	unsigned offStartBlocks;
586	/** Start offset of data in image file, here for speed optimization. */
587	unsigned offStartData;
588	/** Block mask for getting the offset into a block from a byte hdd offset. */
589	unsigned uBlockMask;
590	/** Block shift value for converting byte hdd offset into paBlock index. */
591	unsigned uShiftOffset2Index;
592	#ifndef VBOX_VDICORE_VD
593	/** Block shift value for converting block index into offset in image. */
594	unsigned uShiftIndex2Offset;
595	#endif /* !VBOX_VDICORE_VD */
596	/** Offset of data from the beginning of block. */
597	unsigned offStartBlockData;
598	#ifndef VBOX_VDICORE_VD
599	/** Image is modified flags (VDI_IMAGE_MODIFIED). /
600	unsigned fModified;
601	/** Container filename. (UTF-8)
602	* @todo Make this variable length to save a bunch of bytes. (low prio) */
603	char szFilename[RTPATH_MAX];
604	#else /* VBOX_VDICORE_VD */
605	/** Total size of image block (including the extra data). */
606	unsigned cbTotalBlockData;
607	/** Container filename. (UTF-8) */
608	const char *pszFilename;
609	/** Physical geometry of this image (never actually stored). */
610	VDGEOMETRY PCHSGeometry;
611	/** Pointer to the per-disk VD interface list. */
612	PVDINTERFACE pVDIfsDisk;
613	/** Pointer to the per-image VD interface list. */
614	PVDINTERFACE pVDIfsImage;
615	/** Error interface. */
616	PVDINTERFACE pInterfaceError;
617	/** Error interface callback table. */
618	PVDINTERFACEERROR pInterfaceErrorCallbacks;
619	/** I/O interface. */
620	PVDINTERFACE pInterfaceIO;
621	/** I/O interface callbacks. */
622	PVDINTERFACEIOINT pInterfaceIOCallbacks;
623	#endif /* VBOX_VDICORE_VD */
624	} VDIIMAGEDESC, *PVDIIMAGEDESC;
625
626	#ifndef VBOX_VDICORE_VD
627	/**
628	* Default work buffer size, may be changed by setBufferSize() method.
629	*
630	* For best speed performance it must be equal to image block size.
631	*/
632	#define VDIDISK_DEFAULT_BUFFER_SIZE (VDI_IMAGE_DEFAULT_BLOCK_SIZE)
633	#endif /* !VBOX_VDICORE_VD */
634
635	/** VDIDISK Signature. */
636	#define VDIDISK_SIGNATURE (0xbedafeda)
637
638	/**
639	* VBox HDD Container main structure, private part.
640	*/
641	struct VDIDISK
642	{
643	/** Structure signature (VDIDISK_SIGNATURE). */
644	uint32_t u32Signature;
645
646	/** Number of opened images. */
647	unsigned cImages;
648
649	/** Base image. */
650	PVDIIMAGEDESC pBase;
651
652	/** Last opened image in the chain.
653	* The same as pBase if only one image is used or the last opened diff image. */
654	PVDIIMAGEDESC pLast;
655
656	/** Default block size for newly created images. */
657	unsigned cbBlock;
658
659	/** Working buffer size, allocated only while committing data,
660	* copying block from primary image to secondary and saving previously
661	* zero block. Buffer deallocated after operation complete.
662	* @remark For best performance buffer size must be equal to image's
663	* block size, however it may be decreased for memory saving.
664	*/
665	unsigned cbBuf;
666
667	/** Flag whether zero writes should be handled normally or optimized
668	* away if possible. */
669	bool fHonorZeroWrites;
670
671	#ifndef VBOX_VDICORE_VD
672	/** The media interface. */
673	PDMIMEDIA IMedia;
674	/** Pointer to the driver instance. */
675	PPDMDRVINS pDrvIns;
676	#endif /* !VBOX_VDICORE_VD */
677	};
678
679
680	/*******************************************************************************
681	* Internal Functions *
682	*******************************************************************************/
683	RT_C_DECLS_BEGIN
684
685	#ifndef VBOX_VDICORE_VD
686	VBOXDDU_DECL(void) vdiInitVDIDisk(PVDIDISK pDisk);
687	VBOXDDU_DECL(void) VDIFlushImage(PVDIIMAGEDESC pImage);
688	VBOXDDU_DECL(int) vdiChangeImageMode(PVDIIMAGEDESC pImage, bool fReadOnly);
689	#endif /* !VBOX_VDICORE_VD */
690
691	RT_C_DECLS_END
692
693	#endif

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source: vbox/trunk/src/VBox/Storage/VDICore.h@ 36214

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