[libvirt] [PATCH 3/8] util: add support for qcow2v3 image detection
Ján Tomko
jtomko at redhat.com
Thu May 16 11:07:34 UTC 2013
Detect qcow2 images with version 3 in the image header as
VIR_STORAGE_FILE_QCOW2.
These images have a feature bitfield, with just one feature supported
so far: lazy_refcounts.
The header length changed too, moving the location of the backing
format name.
---
src/util/virstoragefile.c | 164 +++++++++++++++++++++++++++++++++++-----------
src/util/virstoragefile.h | 12 ++++
2 files changed, 139 insertions(+), 37 deletions(-)
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 0c43397..838297b 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -56,6 +56,11 @@ VIR_ENUM_IMPL(virStorageFileFormat,
"qcow", "qcow2", "qed", "vmdk", "vpc",
"fat", "vhd", "vdi")
+VIR_ENUM_IMPL(virStorageFileFeature,
+ VIR_STORAGE_FILE_FEATURE_LAST,
+ "lazy_refcounts",
+ )
+
enum lv_endian {
LV_LITTLE_ENDIAN = 1, /* 1234 */
LV_BIG_ENDIAN /* 4321 */
@@ -77,7 +82,7 @@ struct FileTypeInfo {
int versionOffset; /* Byte offset from start of file
* where we find version number,
* -1 to skip version test */
- int versionNumber; /* Version number to validate */
+ int versionNumbers[3]; /* Version numbers to validate, terminated by 0 */
int sizeOffset; /* Byte offset from start of file
* where we find capacity info,
* -1 to use st_size as capacity */
@@ -91,6 +96,8 @@ struct FileTypeInfo {
* -1 if encryption is not used */
int (*getBackingStore)(char **res, int *format,
const unsigned char *buf, size_t buf_size);
+ int (*getFeatures)(virBitmapPtr *features, int format,
+ unsigned char *buf, ssize_t len);
};
static int cowGetBackingStore(char **, int *,
@@ -99,6 +106,8 @@ static int qcow1GetBackingStore(char **, int *,
const unsigned char *, size_t);
static int qcow2GetBackingStore(char **, int *,
const unsigned char *, size_t);
+static int qcow2GetFeatures(virBitmapPtr *features, int format,
+ unsigned char *buf, ssize_t len);
static int vmdk4GetBackingStore(char **, int *,
const unsigned char *, size_t);
static int
@@ -118,6 +127,13 @@ qedGetBackingStore(char **, int *, const unsigned char *, size_t);
#define QCOW2_HDR_EXTENSION_END 0
#define QCOW2_HDR_EXTENSION_BACKING_FORMAT 0xE2792ACA
+#define QCOW2v3_HDR_FEATURES_INCOMPATIBLE (QCOW2_HDR_TOTAL_SIZE)
+#define QCOW2v3_HDR_FEATURES_COMPATIBLE (QCOW2v3_HDR_FEATURES_INCOMPATIBLE+8)
+#define QCOW2v3_HDR_FEATURES_AUTOCLEAR (QCOW2v3_HDR_FEATURES_COMPATIBLE+8)
+
+/* The location of the header size [4 bytes] */
+#define QCOW2v3_HDR_SIZE (QCOW2_HDR_TOTAL_SIZE+8+8+8+4)
+
#define QED_HDR_FEATURES_OFFSET (4+4+4+4)
#define QED_HDR_IMAGE_SIZE (QED_HDR_FEATURES_OFFSET+8+8+8+8)
#define QED_HDR_BACKING_FILE_OFFSET (QED_HDR_IMAGE_SIZE+8)
@@ -133,16 +149,16 @@ qedGetBackingStore(char **, int *, const unsigned char *, size_t);
static struct FileTypeInfo const fileTypeInfo[] = {
[VIR_STORAGE_FILE_NONE] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
- -1, 0, 0, 0, 0, 0, NULL },
+ -1, {0}, 0, 0, 0, 0, NULL, NULL },
[VIR_STORAGE_FILE_RAW] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
- -1, 0, 0, 0, 0, 0, NULL },
+ -1, {0}, 0, 0, 0, 0, NULL, NULL },
[VIR_STORAGE_FILE_DIR] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
- -1, 0, 0, 0, 0, 0, NULL },
+ -1, {0}, 0, 0, 0, 0, NULL, NULL },
[VIR_STORAGE_FILE_BOCHS] = {
/*"Bochs Virtual HD Image", */ /* Untested */
0, NULL, NULL,
- LV_LITTLE_ENDIAN, 64, 0x20000,
- 32+16+16+4+4+4+4+4, 8, 1, -1, NULL
+ LV_LITTLE_ENDIAN, 64, {0x20000, 0},
+ 32+16+16+4+4+4+4+4, 8, 1, -1, NULL, NULL
},
[VIR_STORAGE_FILE_CLOOP] = {
/* #!/bin/sh
@@ -150,67 +166,82 @@ static struct FileTypeInfo const fileTypeInfo[] = {
modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1
*/ /* Untested */
0, NULL, NULL,
- LV_LITTLE_ENDIAN, -1, 0,
- -1, 0, 0, -1, NULL
+ LV_LITTLE_ENDIAN, -1, {0},
+ -1, 0, 0, -1, NULL, NULL
},
[VIR_STORAGE_FILE_COW] = {
0, "OOOM", NULL,
- LV_BIG_ENDIAN, 4, 2,
- 4+4+1024+4, 8, 1, -1, cowGetBackingStore
+ LV_BIG_ENDIAN, 4, {2, 0},
+ 4+4+1024+4, 8, 1, -1, cowGetBackingStore, NULL
},
[VIR_STORAGE_FILE_DMG] = {
/* XXX QEMU says there's no magic for dmg,
* /usr/share/misc/magic lists double magic (both offsets
* would have to match) but then disables that check. */
0, NULL, ".dmg",
- 0, -1, 0,
- -1, 0, 0, -1, NULL
+ 0, -1, {0},
+ -1, 0, 0, -1, NULL, NULL
},
[VIR_STORAGE_FILE_ISO] = {
32769, "CD001", ".iso",
- LV_LITTLE_ENDIAN, -2, 0,
- -1, 0, 0, -1, NULL
+ LV_LITTLE_ENDIAN, -2, {0},
+ -1, 0, 0, -1, NULL, NULL
},
[VIR_STORAGE_FILE_QCOW] = {
0, "QFI", NULL,
- LV_BIG_ENDIAN, 4, 1,
- QCOWX_HDR_IMAGE_SIZE, 8, 1, QCOW1_HDR_CRYPT, qcow1GetBackingStore,
+ LV_BIG_ENDIAN, 4, {1, 0},
+ QCOWX_HDR_IMAGE_SIZE, 8, 1, QCOW1_HDR_CRYPT, qcow1GetBackingStore, NULL
},
[VIR_STORAGE_FILE_QCOW2] = {
0, "QFI", NULL,
- LV_BIG_ENDIAN, 4, 2,
+ LV_BIG_ENDIAN, 4, {2, 3},
QCOWX_HDR_IMAGE_SIZE, 8, 1, QCOW2_HDR_CRYPT, qcow2GetBackingStore,
+ qcow2GetFeatures
},
[VIR_STORAGE_FILE_QED] = {
/* http://wiki.qemu.org/Features/QED */
0, "QED", NULL,
- LV_LITTLE_ENDIAN, -2, -1,
- QED_HDR_IMAGE_SIZE, 8, 1, -1, qedGetBackingStore,
+ LV_LITTLE_ENDIAN, -2, {0},
+ QED_HDR_IMAGE_SIZE, 8, 1, -1, qedGetBackingStore, NULL
},
[VIR_STORAGE_FILE_VMDK] = {
0, "KDMV", NULL,
- LV_LITTLE_ENDIAN, 4, 1,
- 4+4+4, 8, 512, -1, vmdk4GetBackingStore
+ LV_LITTLE_ENDIAN, 4, {1, 0},
+ 4+4+4, 8, 512, -1, vmdk4GetBackingStore, NULL
},
[VIR_STORAGE_FILE_VPC] = {
0, "conectix", NULL,
- LV_BIG_ENDIAN, 12, 0x10000,
- 8 + 4 + 4 + 8 + 4 + 4 + 2 + 2 + 4, 8, 1, -1, NULL
+ LV_BIG_ENDIAN, 12, {0x10000, 0},
+ 8 + 4 + 4 + 8 + 4 + 4 + 2 + 2 + 4, 8, 1, -1, NULL, NULL
},
/* TODO: add getBackingStore function */
[VIR_STORAGE_FILE_VDI] = {
64, "\x7f\x10\xda\xbe", ".vdi",
- LV_LITTLE_ENDIAN, 68, 0x00010001,
- 64 + 5 * 4 + 256 + 7 * 4, 8, 1, -1, NULL},
+ LV_LITTLE_ENDIAN, 68, {0x00010001, 0},
+ 64 + 5 * 4 + 256 + 7 * 4, 8, 1, -1, NULL, NULL},
/* Not direct file formats, but used for various drivers */
[VIR_STORAGE_FILE_FAT] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
- -1, 0, 0, 0, 0, 0, NULL },
+ -1, {0}, 0, 0, 0, 0, NULL, NULL },
[VIR_STORAGE_FILE_VHD] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
- -1, 0, 0, 0, 0, 0, NULL },
+ -1, {0}, 0, 0, 0, 0, NULL, NULL },
};
verify(ARRAY_CARDINALITY(fileTypeInfo) == VIR_STORAGE_FILE_LAST);
+/* qcow2 compatible features in the order they appear on-disk */
+enum qcow2CompatibleFeature {
+ QCOW2_COMPATIBLE_FEATURE_LAZY_REFCOUNTS = 0,
+
+ QCOW2_COMPATIBLE_FEATURE_LAST
+};
+
+/* conversion to virStorageFeatures */
+static int qcow2CompatibleFeatureArray[] = {
+ VIR_STORAGE_FILE_FEATURE_LAZY_REFCOUNTS,
+};
+verify(ARRAY_CARDINALITY(qcow2CompatibleFeatureArray) ==
+ QCOW2_COMPATIBLE_FEATURE_LAST);
+
static int
cowGetBackingStore(char **res,
int *format,
@@ -300,6 +331,8 @@ qcowXGetBackingStore(char **res,
{
unsigned long long offset;
unsigned int size;
+ unsigned long long start;
+ int version;
*res = NULL;
if (format)
@@ -350,11 +383,20 @@ qcowXGetBackingStore(char **res,
* Thus the file region to search for extensions is
* between the end of the header (QCOW2_HDR_TOTAL_SIZE)
* and the start of the backingStoreName (offset)
+ *
+ * for qcow2 v3 images, the length of the header
+ * is stored at QCOW2v3_HDR_SIZE
*/
- if (isQCow2 && format &&
- qcow2GetBackingStoreFormat(format, buf, buf_size, QCOW2_HDR_TOTAL_SIZE,
- offset) < 0)
- return BACKING_STORE_INVALID;
+ if (isQCow2 && format) {
+ version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION);
+ if (version == 2)
+ start = QCOW2_HDR_TOTAL_SIZE;
+ else
+ start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE);
+ if (qcow2GetBackingStoreFormat(format, buf, buf_size,
+ start, offset) < 0)
+ return BACKING_STORE_INVALID;
+ }
return BACKING_STORE_OK;
}
@@ -595,7 +637,7 @@ virStorageFileMatchesVersion(int format,
unsigned char *buf,
size_t buflen)
{
- int version;
+ int version, i;
/* Validate version number info */
if (fileTypeInfo[format].versionOffset == -1)
@@ -613,12 +655,14 @@ virStorageFileMatchesVersion(int format,
else
version = virReadBufInt32BE(buf + fileTypeInfo[format].versionOffset);
- VIR_DEBUG("Compare detected version %d vs expected version %d",
- version, fileTypeInfo[format].versionNumber);
- if (version != fileTypeInfo[format].versionNumber)
- return false;
+ for (i = 0; fileTypeInfo[format].versionNumbers[i] != 0; i++) {
+ VIR_DEBUG("Compare detected version %d vs expected version %d",
+ version, fileTypeInfo[format].versionNumbers[i]);
+ if (version == fileTypeInfo[format].versionNumbers[i])
+ return true;
+ }
- return true;
+ return false;
}
static bool
@@ -671,6 +715,42 @@ cleanup:
}
+static int
+qcow2GetFeatures(virBitmapPtr *features,
+ int format,
+ unsigned char *buf,
+ ssize_t len)
+{
+ int version = -1;
+ virBitmapPtr feat = NULL;
+ uint64_t bits;
+ int i;
+
+ version = virReadBufInt32BE(buf + fileTypeInfo[format].versionOffset);
+
+ if (version == 2)
+ return 0;
+
+ if (len < QCOW2v3_HDR_SIZE)
+ return -1;
+
+ if (!(feat = virBitmapNew(VIR_STORAGE_FILE_FEATURE_LAST))) {
+ virReportOOMError();
+ return -1;
+ }
+
+ /* todo: check for incompatible or autoclear features? */
+ bits = virReadBufInt64BE(buf + QCOW2v3_HDR_FEATURES_COMPATIBLE);
+ for (i = 0; i < QCOW2_COMPATIBLE_FEATURE_LAST; i++) {
+ if (bits & ((uint64_t) 1 << i))
+ ignore_value(virBitmapSetBit(feat, qcow2CompatibleFeatureArray[i]));
+ }
+
+ *features = feat;
+ return 0;
+}
+
+
/* Given a file descriptor FD open on PATH, and optionally opened from
* a given DIRECTORY, return metadata about that file, assuming it has
* the given FORMAT. */
@@ -807,6 +887,14 @@ virStorageFileGetMetadataInternal(const char *path,
}
}
+ if (fileTypeInfo[format].getFeatures != NULL &&
+ fileTypeInfo[format].getFeatures(&meta->features, format, buf, len) < 0)
+ goto cleanup;
+
+ if (format == VIR_STORAGE_FILE_QCOW2 && meta->features &&
+ VIR_STRDUP(meta->compat, "1.1") < 0)
+ goto cleanup;
+
done:
ret = meta;
meta = NULL;
@@ -1036,7 +1124,9 @@ virStorageFileFreeMetadata(virStorageFileMetadata *meta)
virStorageFileFreeMetadata(meta->backingMeta);
VIR_FREE(meta->backingStore);
VIR_FREE(meta->backingStoreRaw);
+ VIR_FREE(meta->compat);
VIR_FREE(meta->directory);
+ virBitmapFree(meta->features);
VIR_FREE(meta);
}
diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h
index ffe7a54..ee048da 100644
--- a/src/util/virstoragefile.h
+++ b/src/util/virstoragefile.h
@@ -24,6 +24,7 @@
#ifndef __VIR_STORAGE_FILE_H__
# define __VIR_STORAGE_FILE_H__
+# include "virbitmap.h"
# include "virutil.h"
enum virStorageFileFormat {
@@ -51,6 +52,15 @@ enum virStorageFileFormat {
VIR_ENUM_DECL(virStorageFileFormat);
+enum virStorageFileFeature {
+ VIR_STORAGE_FILE_FEATURE_NONE = -1,
+ VIR_STORAGE_FILE_FEATURE_LAZY_REFCOUNTS,
+
+ VIR_STORAGE_FILE_FEATURE_LAST
+};
+
+VIR_ENUM_DECL(virStorageFileFeature);
+
typedef struct _virStorageFileMetadata virStorageFileMetadata;
typedef virStorageFileMetadata *virStorageFileMetadataPtr;
struct _virStorageFileMetadata {
@@ -62,6 +72,8 @@ struct _virStorageFileMetadata {
virStorageFileMetadataPtr backingMeta;
unsigned long long capacity;
bool encrypted;
+ virBitmapPtr features; /* bits described by enum virStorageFileFeature */
+ char *compat;
};
# ifndef DEV_BSIZE
--
1.8.1.5
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