Patchwork block.c, block/vmdk.c: Fixed major bug in VMDK WRITE and READ handling - FIXES DATA CORRUPTION

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Submitter Gerhard Wiesinger
Date Nov. 8, 2012, 7:05 p.m.
Message ID <alpine.LFD.2.02.1211082005160.4272@bbs.intern>
Download mbox | patch
Permalink /patch/197870/
State New
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Gerhard Wiesinger - Nov. 8, 2012, 7:05 p.m.
Fixed a MAJOR BUG in VMDK files on file boundaries on reads
and ALSO ON WRITES WHICH MIGHT CORRUPT THE IMAGE AND DATA!!!!!!

Triggered for example with the following VMDK file (partly listed):
# Extent description
RW 4193792 FLAT "XP-W1-f001.vmdk" 0
RW 2097664 FLAT "XP-W1-f002.vmdk" 0
RW 4193792 FLAT "XP-W1-f003.vmdk" 0
RW 512 FLAT "XP-W1-f004.vmdk" 0
RW 4193792 FLAT "XP-W1-f005.vmdk" 0
RW 2097664 FLAT "XP-W1-f006.vmdk" 0
RW 4193792 FLAT "XP-W1-f007.vmdk" 0
RW 512 FLAT "XP-W1-f008.vmdk" 0

Patch includes:
1.) Patch fixes wrong calculation on extent boundaries. Especially it fixes the relativeness of the sector number to the current extent.
2.) Added debug code to block.c and to block/vmdk.c to verify correctness
3.) Also optimized code which avoids multiplication and uses shifts.

Verfied correctness with:
1.) Converted either with Virtualbox to VDI and then with qemu-img and then with qemu-img only
VBoxManage clonehd --format vdi /VM/XP-W/new/XP-W1.vmdk ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
./qemu-img convert -O raw ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi /root/QEMU/VM-XP-W1/XP-W1-via-VBOX.img
md5sum /root/QEMU/VM-XP-W/XP-W1-direct.img
md5sum /root/QEMU/VM-XP-W/XP-W1-via-VBOX.img
=> same MD5 hash
2.) Verified debug log files
3.) Run Windows XP successfully
4.) chkdsk run successfully without any errors

Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
---
  block.c      |  50 +++++++++++++++++++++++
  block/vmdk.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
  2 files changed, 170 insertions(+), 9 deletions(-)
Feiran Zheng - Nov. 9, 2012, 5:12 a.m.
Yes, I can confirm the presence of this bug and this is a valid fix.

May I ask where is this kind of vmdk from? Because regularly we see
extents in identical size.

---
Best regards!
Fam Zheng


On Fri, Nov 9, 2012 at 3:05 AM, Gerhard Wiesinger <lists@wiesinger.com> wrote:
> Fixed a MAJOR BUG in VMDK files on file boundaries on reads
> and ALSO ON WRITES WHICH MIGHT CORRUPT THE IMAGE AND DATA!!!!!!
>
> Triggered for example with the following VMDK file (partly listed):
> # Extent description
> RW 4193792 FLAT "XP-W1-f001.vmdk" 0
> RW 2097664 FLAT "XP-W1-f002.vmdk" 0
> RW 4193792 FLAT "XP-W1-f003.vmdk" 0
> RW 512 FLAT "XP-W1-f004.vmdk" 0
> RW 4193792 FLAT "XP-W1-f005.vmdk" 0
> RW 2097664 FLAT "XP-W1-f006.vmdk" 0
> RW 4193792 FLAT "XP-W1-f007.vmdk" 0
> RW 512 FLAT "XP-W1-f008.vmdk" 0
>
> Patch includes:
> 1.) Patch fixes wrong calculation on extent boundaries. Especially it fixes
> the relativeness of the sector number to the current extent.
> 2.) Added debug code to block.c and to block/vmdk.c to verify correctness
> 3.) Also optimized code which avoids multiplication and uses shifts.
>
> Verfied correctness with:
> 1.) Converted either with Virtualbox to VDI and then with qemu-img and then
> with qemu-img only
> VBoxManage clonehd --format vdi /VM/XP-W/new/XP-W1.vmdk
> ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
> ./qemu-img convert -O raw ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
> /root/QEMU/VM-XP-W1/XP-W1-via-VBOX.img
> md5sum /root/QEMU/VM-XP-W/XP-W1-direct.img
> md5sum /root/QEMU/VM-XP-W/XP-W1-via-VBOX.img
> => same MD5 hash
> 2.) Verified debug log files
> 3.) Run Windows XP successfully
> 4.) chkdsk run successfully without any errors
>
> Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
> ---
>  block.c      |  50 +++++++++++++++++++++++
>  block/vmdk.c | 129
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
>  2 files changed, 170 insertions(+), 9 deletions(-)
>
> diff --git a/block.c b/block.c
> index da1fdca..69259f2 100644
> --- a/block.c
> +++ b/block.c
> @@ -49,6 +49,12 @@
>  #include <windows.h>
>  #endif
>
> +#if 0
> +   #define DEBUG_BLOCK
> +#endif
> +
> +#define DEBUG_BLOCK_PREFIX "BLOCK: "
> +
>  #define NOT_DONE 0x7fffffff /* used while emulated sync operation in
> progress */
>
>  typedef enum {
> @@ -789,6 +795,18 @@ int bdrv_open(BlockDriverState *bs, const char
> *filename, int flags,
>      int ret;
>      char tmp_filename[PATH_MAX];
>
> +#ifdef DEBUG_BLOCK
> +    const char *format = "(nil)";
> +    if (drv) {
> +        format = drv->format_name;
> +    }
> +
> +    printf(DEBUG_BLOCK
> +           "bdrv_open: filename=%s, BlockDriver=%p, format=%s\n",
> +           filename, drv, format
> +           );
> +#endif
> +
>      if (flags & BDRV_O_SNAPSHOT) {
>          BlockDriverState *bs1;
>          int64_t total_size;
> @@ -2004,6 +2022,22 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t
> sector_num, uint8_t *buf,
>  int bdrv_read(BlockDriverState *bs, int64_t sector_num,
>                uint8_t *buf, int nb_sectors)
>  {
> +#ifdef DEBUG_BLOCK
> +    BlockDriver *drv = bs->drv;
> +    const char *format_name = "(nil)";
> +    if (drv) {
> +        if (drv->format_name) {
> +            format_name = drv->format_name;
> +        }
> +    }
> +
> +    printf(DEBUG_BLOCK
> +           "bdrv_read: driver=%s, filename=%s, sector_num=%" PRId64
> +           ", nb_sectors=%i\n",
> +           format_name, bs->filename, sector_num, nb_sectors
> +           );
> +#endif
> +
>      return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
>  }
>
> @@ -2060,6 +2094,22 @@ static void set_dirty_bitmap(BlockDriverState *bs,
> int64_t sector_num,
>  int bdrv_write(BlockDriverState *bs, int64_t sector_num,
>                 const uint8_t *buf, int nb_sectors)
>  {
> +#ifdef DEBUG_BLOCK
> +    BlockDriver *drv = bs->drv;
> +    const char *format_name = "(nil)";
> +    if (drv) {
> +        if (drv->format_name) {
> +            format_name = drv->format_name;
> +        }
> +    }
> +
> +    printf(DEBUG_BLOCK
> +           "bdrv_write: driver=%s, filename=%s, sector_num=%" PRId64
> +           ", nb_sectors=%i\n",
> +           format_name, bs->filename, sector_num, nb_sectors
> +           );
> +#endif
> +
>      return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true);
>  }
>
> diff --git a/block/vmdk.c b/block/vmdk.c
> index 1a80e5a..92ab92c 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -29,6 +29,15 @@
>  #include "migration.h"
>  #include <zlib.h>
>
> +#if 0
> +    #define DEBUG_VMDK
> +#endif
> +
> +#define DEBUG_VMDK_PREFIX "VMDK: "
> +#define DEBUG_VMDK_SEPARATOR \
> +        "########################################" \
> +        "########################################"
> +
>  #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
>  #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
>  #define VMDK4_COMPRESSION_DEFLATE 1
> @@ -377,6 +386,16 @@ static VmdkExtent *vmdk_add_extent(BlockDriverState
> *bs,
>      VmdkExtent *extent;
>      BDRVVmdkState *s = bs->opaque;
>
> +#ifdef DEBUG_VMDK
> +    printf(DEBUG_VMDK_PREFIX
> +           "vmdk_add_extent: flat=%i, sectors=%" PRId64
> +           ", l1_backup_offset=%" PRId64
> +           ", l1_size=%u, l2_size=%i, cluster_sectors=%u\n",
> +           (int)flat, sectors, l1_backup_offset,
> +           l1_size, l2_size, cluster_sectors
> +           );
> +#endif
> +
>      s->extents = g_realloc(s->extents,
>                                (s->num_extents + 1) * sizeof(VmdkExtent));
>      extent = &s->extents[s->num_extents];
> @@ -674,6 +693,14 @@ static int vmdk_parse_extents(const char *desc,
> BlockDriverState *bs,
>              return ret;
>          }
>
> +#ifdef DEBUG_VMDK
> +        printf(DEBUG_VMDK_PREFIX
> +               "valid extent found: access=%s, sectors=%" PRId64
> +               ", type=%s, filename=%s, flat_offset=%" PRId64 "\n",
> +               access, sectors, type, fname, flat_offset
> +               );
> +#endif
> +
>          /* save to extents array */
>          if (!strcmp(type, "FLAT")) {
>              /* FLAT extent */
> @@ -704,6 +731,45 @@ next_line:
>      return 0;
>  }
>
> +#ifdef DEBUG_VMDK
> +static void vmdk_debug_print_one_extent(VmdkExtent *extent)
> +{
> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
> +    printf(DEBUG_VMDK_PREFIX "filename%s\n", extent->file->filename);
> +    printf(DEBUG_VMDK_PREFIX "flat=%i\n", (int)extent->flat);
> +    printf(DEBUG_VMDK_PREFIX "compressed=%i\n", (int)extent->compressed);
> +    printf(DEBUG_VMDK_PREFIX "has_marker=%i\n", (int)extent->has_marker);
> +    printf(DEBUG_VMDK_PREFIX "sectors=%" PRId64 "\n", extent->sectors);
> +    printf(DEBUG_VMDK_PREFIX "end_sector=%" PRId64 "\n",
> extent->end_sector);
> +    printf(DEBUG_VMDK_PREFIX "flat_start_offset=%" PRId64 "\n",
> +                             extent->flat_start_offset);
> +    printf(DEBUG_VMDK_PREFIX "l1_table_offsett=%" PRId64 "\n",
> +                             extent->l1_table_offset);
> +    printf(DEBUG_VMDK_PREFIX "l1_backup_table_offsett=%"
> +                             PRId64 "\n", extent->l1_backup_table_offset);
> +    printf(DEBUG_VMDK_PREFIX "l1_size=%u\n", extent->l1_size);
> +    printf(DEBUG_VMDK_PREFIX "l1_entry_sectors=%u\n",
> extent->l1_entry_sectors);
> +    printf(DEBUG_VMDK_PREFIX "l2_size=%u\n", extent->l2_size);
> +    printf(DEBUG_VMDK_PREFIX "cluster_sectors=%u\n",
> extent->cluster_sectors);
> +    fflush(stdout);
> +}
> +
> +static void vmdk_debug_print_extents(BlockDriverState *bs)
> +{
> +    BDRVVmdkState *s = bs->opaque;
> +    VmdkExtent *extent = &s->extents[0];
> +
> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
> +    printf(DEBUG_VMDK_PREFIX "total_sectors=%" PRId64 "\n",
> bs->total_sectors);
> +    printf(DEBUG_VMDK_PREFIX "num_extents=%u\n", s->num_extents);
> +
> +    while (extent < &s->extents[s->num_extents]) {
> +        vmdk_debug_print_one_extent(extent);
> +        extent++;
> +    }
> +}
> +#endif
> +
>  static int vmdk_open_desc_file(BlockDriverState *bs, int flags,
>                                 int64_t desc_offset)
>  {
> @@ -728,7 +794,13 @@ static int vmdk_open_desc_file(BlockDriverState *bs,
> int flags,
>          return -ENOTSUP;
>      }
>      s->desc_offset = 0;
> -    return vmdk_parse_extents(buf, bs, bs->file->filename);
> +    ret = vmdk_parse_extents(buf, bs, bs->file->filename);
> +
> +#ifdef DEBUG_VMDK
> +    vmdk_debug_print_extents(bs);
> +#endif
> +
> +    return ret;
>  }
>
>  static int vmdk_open(BlockDriverState *bs, int flags)
> @@ -774,6 +846,14 @@ static int get_whole_cluster(BlockDriverState *bs,
>      /* 128 sectors * 512 bytes each = grain size 64KB */
>      uint8_t  whole_grain[extent->cluster_sectors * 512];
>
> +#ifdef DEBUG_VMDK
> +    printf(DEBUG_VMDK_PREFIX
> +           "vmdk_get_whole_cluster: filename=%s, cluster_offset=%" PRId64
> +           ", offset=%" PRId64 "\n",
> +           extent->file->filename, cluster_offset, offset
> +           );
> +#endif
> +
>      /* we will be here if it's first write on non-exist grain(cluster).
>       * try to read from parent image, if exist */
>      if (bs->backing_hd) {
> @@ -1032,18 +1112,35 @@ static int vmdk_read_extent(VmdkExtent *extent,
> int64_t cluster_offset,
>      VmdkGrainMarker *marker;
>      uLongf buf_len;
>
> +#ifdef DEBUG_VMDK
> +    printf(DEBUG_VMDK_PREFIX
> +           "vmdk_read_extent: filename=%s, cluster_offset=%" PRId64
> +           ", offset_in_cluster=%" PRId64 ", nb_sectors=%i\n",
> +           extent->file->filename, cluster_offset,
> +           offset_in_cluster, nb_sectors
> +           );
> +#endif
>
>      if (!extent->compressed) {
> +
> +#ifdef DEBUG_VMDK
> +        printf(DEBUG_VMDK_PREFIX
> +               "vmdk_read_extent:bdrv_pread filename=%s, offset=%" PRId64
> +               ", length=%i\n",
> +               extent->file->filename, offset_in_cluster, nb_sectors << 9
> +               );
> +#endif
> +
>          ret = bdrv_pread(extent->file,
>                            cluster_offset + offset_in_cluster,
> -                          buf, nb_sectors * 512);
> -        if (ret == nb_sectors * 512) {
> +                          buf, nb_sectors << 9);
> +        if (ret == nb_sectors << 9) {
>              return 0;
>          } else {
>              return -EIO;
>          }
>      }
> -    cluster_bytes = extent->cluster_sectors * 512;
> +    cluster_bytes = extent->cluster_sectors << 9;
>      /* Read two clusters in case GrainMarker + compressed data > one
> cluster */
>      buf_bytes = cluster_bytes * 2;
>      cluster_buf = g_malloc(buf_bytes);
> @@ -1092,9 +1189,18 @@ static int vmdk_read(BlockDriverState *bs, int64_t
> sector_num,
>      BDRVVmdkState *s = bs->opaque;
>      int ret;
>      uint64_t n, index_in_cluster;
> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>      VmdkExtent *extent = NULL;
>      uint64_t cluster_offset;
>
> +#ifdef DEBUG_VMDK
> +    printf(DEBUG_VMDK_PREFIX
> +           "vmdk_read: sectornum=%" PRId64
> +           ", nb_sectors=%i\n",
> +           sector_num, nb_sectors
> +           );
> +#endif
> +
>      while (nb_sectors > 0) {
>          extent = find_extent(s, sector_num, extent);
>          if (!extent) {
> @@ -1103,7 +1209,9 @@ static int vmdk_read(BlockDriverState *bs, int64_t
> sector_num,
>          ret = get_cluster_offset(
>                              bs, extent, NULL,
>                              sector_num << 9, 0, &cluster_offset);
> -        index_in_cluster = sector_num % extent->cluster_sectors;
> +        extent_begin_sector = extent->end_sector - extent->sectors;
> +        extent_relative_sector_num = sector_num - extent_begin_sector;
> +        index_in_cluster = extent_relative_sector_num %
> extent->cluster_sectors;
>          n = extent->cluster_sectors - index_in_cluster;
>          if (n > nb_sectors) {
>              n = nb_sectors;
> @@ -1119,11 +1227,11 @@ static int vmdk_read(BlockDriverState *bs, int64_t
> sector_num,
>                      return ret;
>                  }
>              } else {
> -                memset(buf, 0, 512 * n);
> +                memset(buf, 0, n << 9);
>              }
>          } else {
>              ret = vmdk_read_extent(extent,
> -                            cluster_offset, index_in_cluster * 512,
> +                            cluster_offset, index_in_cluster << 9,
>                              buf, n);
>              if (ret) {
>                  return ret;
> @@ -1131,7 +1239,7 @@ static int vmdk_read(BlockDriverState *bs, int64_t
> sector_num,
>          }
>          nb_sectors -= n;
>          sector_num += n;
> -        buf += n * 512;
> +        buf += n << 9;
>      }
>      return 0;
>  }
> @@ -1154,6 +1262,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t
> sector_num,
>      VmdkExtent *extent = NULL;
>      int n, ret;
>      int64_t index_in_cluster;
> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>      uint64_t cluster_offset;
>      VmdkMetaData m_data;
>
> @@ -1196,7 +1305,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t
> sector_num,
>          if (ret) {
>              return -EINVAL;
>          }
> -        index_in_cluster = sector_num % extent->cluster_sectors;
> +        extent_begin_sector = extent->end_sector - extent->sectors;
> +        extent_relative_sector_num = sector_num - extent_begin_sector;
> +        index_in_cluster = extent_relative_sector_num %
> extent->cluster_sectors;
>          n = extent->cluster_sectors - index_in_cluster;
>          if (n > nb_sectors) {
>              n = nb_sectors;
> --
> 1.7.11.7
>
Gerhard Wiesinger - Nov. 9, 2012, 6:51 a.m.
Hello,

It was created with VMWare Server 2.0.x or maybe even with 1.x. under Linux.

Ciao,
Gerhard

On 09.11.2012 06:12, Fam Zheng wrote:
> Yes, I can confirm the presence of this bug and this is a valid fix.
>
> May I ask where is this kind of vmdk from? Because regularly we see
> extents in identical size.
>
> ---
> Best regards!
> Fam Zheng
>
>
> On Fri, Nov 9, 2012 at 3:05 AM, Gerhard Wiesinger <lists@wiesinger.com> wrote:
>> Fixed a MAJOR BUG in VMDK files on file boundaries on reads
>> and ALSO ON WRITES WHICH MIGHT CORRUPT THE IMAGE AND DATA!!!!!!
>>
>> Triggered for example with the following VMDK file (partly listed):
>> # Extent description
>> RW 4193792 FLAT "XP-W1-f001.vmdk" 0
>> RW 2097664 FLAT "XP-W1-f002.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f003.vmdk" 0
>> RW 512 FLAT "XP-W1-f004.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f005.vmdk" 0
>> RW 2097664 FLAT "XP-W1-f006.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f007.vmdk" 0
>> RW 512 FLAT "XP-W1-f008.vmdk" 0
>>
>> Patch includes:
>> 1.) Patch fixes wrong calculation on extent boundaries. Especially it fixes
>> the relativeness of the sector number to the current extent.
>> 2.) Added debug code to block.c and to block/vmdk.c to verify correctness
>> 3.) Also optimized code which avoids multiplication and uses shifts.
>>
>> Verfied correctness with:
>> 1.) Converted either with Virtualbox to VDI and then with qemu-img and then
>> with qemu-img only
>> VBoxManage clonehd --format vdi /VM/XP-W/new/XP-W1.vmdk
>> ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
>> ./qemu-img convert -O raw ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
>> /root/QEMU/VM-XP-W1/XP-W1-via-VBOX.img
>> md5sum /root/QEMU/VM-XP-W/XP-W1-direct.img
>> md5sum /root/QEMU/VM-XP-W/XP-W1-via-VBOX.img
>> => same MD5 hash
>> 2.) Verified debug log files
>> 3.) Run Windows XP successfully
>> 4.) chkdsk run successfully without any errors
>>
>> Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
>> ---
>>   block.c      |  50 +++++++++++++++++++++++
>>   block/vmdk.c | 129
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
>>   2 files changed, 170 insertions(+), 9 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index da1fdca..69259f2 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -49,6 +49,12 @@
>>   #include <windows.h>
>>   #endif
>>
>> +#if 0
>> +   #define DEBUG_BLOCK
>> +#endif
>> +
>> +#define DEBUG_BLOCK_PREFIX "BLOCK: "
>> +
>>   #define NOT_DONE 0x7fffffff /* used while emulated sync operation in
>> progress */
>>
>>   typedef enum {
>> @@ -789,6 +795,18 @@ int bdrv_open(BlockDriverState *bs, const char
>> *filename, int flags,
>>       int ret;
>>       char tmp_filename[PATH_MAX];
>>
>> +#ifdef DEBUG_BLOCK
>> +    const char *format = "(nil)";
>> +    if (drv) {
>> +        format = drv->format_name;
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_open: filename=%s, BlockDriver=%p, format=%s\n",
>> +           filename, drv, format
>> +           );
>> +#endif
>> +
>>       if (flags & BDRV_O_SNAPSHOT) {
>>           BlockDriverState *bs1;
>>           int64_t total_size;
>> @@ -2004,6 +2022,22 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t
>> sector_num, uint8_t *buf,
>>   int bdrv_read(BlockDriverState *bs, int64_t sector_num,
>>                 uint8_t *buf, int nb_sectors)
>>   {
>> +#ifdef DEBUG_BLOCK
>> +    BlockDriver *drv = bs->drv;
>> +    const char *format_name = "(nil)";
>> +    if (drv) {
>> +        if (drv->format_name) {
>> +            format_name = drv->format_name;
>> +        }
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_read: driver=%s, filename=%s, sector_num=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           format_name, bs->filename, sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
>>   }
>>
>> @@ -2060,6 +2094,22 @@ static void set_dirty_bitmap(BlockDriverState *bs,
>> int64_t sector_num,
>>   int bdrv_write(BlockDriverState *bs, int64_t sector_num,
>>                  const uint8_t *buf, int nb_sectors)
>>   {
>> +#ifdef DEBUG_BLOCK
>> +    BlockDriver *drv = bs->drv;
>> +    const char *format_name = "(nil)";
>> +    if (drv) {
>> +        if (drv->format_name) {
>> +            format_name = drv->format_name;
>> +        }
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_write: driver=%s, filename=%s, sector_num=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           format_name, bs->filename, sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true);
>>   }
>>
>> diff --git a/block/vmdk.c b/block/vmdk.c
>> index 1a80e5a..92ab92c 100644
>> --- a/block/vmdk.c
>> +++ b/block/vmdk.c
>> @@ -29,6 +29,15 @@
>>   #include "migration.h"
>>   #include <zlib.h>
>>
>> +#if 0
>> +    #define DEBUG_VMDK
>> +#endif
>> +
>> +#define DEBUG_VMDK_PREFIX "VMDK: "
>> +#define DEBUG_VMDK_SEPARATOR \
>> +        "########################################" \
>> +        "########################################"
>> +
>>   #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
>>   #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
>>   #define VMDK4_COMPRESSION_DEFLATE 1
>> @@ -377,6 +386,16 @@ static VmdkExtent *vmdk_add_extent(BlockDriverState
>> *bs,
>>       VmdkExtent *extent;
>>       BDRVVmdkState *s = bs->opaque;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_add_extent: flat=%i, sectors=%" PRId64
>> +           ", l1_backup_offset=%" PRId64
>> +           ", l1_size=%u, l2_size=%i, cluster_sectors=%u\n",
>> +           (int)flat, sectors, l1_backup_offset,
>> +           l1_size, l2_size, cluster_sectors
>> +           );
>> +#endif
>> +
>>       s->extents = g_realloc(s->extents,
>>                                 (s->num_extents + 1) * sizeof(VmdkExtent));
>>       extent = &s->extents[s->num_extents];
>> @@ -674,6 +693,14 @@ static int vmdk_parse_extents(const char *desc,
>> BlockDriverState *bs,
>>               return ret;
>>           }
>>
>> +#ifdef DEBUG_VMDK
>> +        printf(DEBUG_VMDK_PREFIX
>> +               "valid extent found: access=%s, sectors=%" PRId64
>> +               ", type=%s, filename=%s, flat_offset=%" PRId64 "\n",
>> +               access, sectors, type, fname, flat_offset
>> +               );
>> +#endif
>> +
>>           /* save to extents array */
>>           if (!strcmp(type, "FLAT")) {
>>               /* FLAT extent */
>> @@ -704,6 +731,45 @@ next_line:
>>       return 0;
>>   }
>>
>> +#ifdef DEBUG_VMDK
>> +static void vmdk_debug_print_one_extent(VmdkExtent *extent)
>> +{
>> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
>> +    printf(DEBUG_VMDK_PREFIX "filename%s\n", extent->file->filename);
>> +    printf(DEBUG_VMDK_PREFIX "flat=%i\n", (int)extent->flat);
>> +    printf(DEBUG_VMDK_PREFIX "compressed=%i\n", (int)extent->compressed);
>> +    printf(DEBUG_VMDK_PREFIX "has_marker=%i\n", (int)extent->has_marker);
>> +    printf(DEBUG_VMDK_PREFIX "sectors=%" PRId64 "\n", extent->sectors);
>> +    printf(DEBUG_VMDK_PREFIX "end_sector=%" PRId64 "\n",
>> extent->end_sector);
>> +    printf(DEBUG_VMDK_PREFIX "flat_start_offset=%" PRId64 "\n",
>> +                             extent->flat_start_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_table_offsett=%" PRId64 "\n",
>> +                             extent->l1_table_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_backup_table_offsett=%"
>> +                             PRId64 "\n", extent->l1_backup_table_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_size=%u\n", extent->l1_size);
>> +    printf(DEBUG_VMDK_PREFIX "l1_entry_sectors=%u\n",
>> extent->l1_entry_sectors);
>> +    printf(DEBUG_VMDK_PREFIX "l2_size=%u\n", extent->l2_size);
>> +    printf(DEBUG_VMDK_PREFIX "cluster_sectors=%u\n",
>> extent->cluster_sectors);
>> +    fflush(stdout);
>> +}
>> +
>> +static void vmdk_debug_print_extents(BlockDriverState *bs)
>> +{
>> +    BDRVVmdkState *s = bs->opaque;
>> +    VmdkExtent *extent = &s->extents[0];
>> +
>> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
>> +    printf(DEBUG_VMDK_PREFIX "total_sectors=%" PRId64 "\n",
>> bs->total_sectors);
>> +    printf(DEBUG_VMDK_PREFIX "num_extents=%u\n", s->num_extents);
>> +
>> +    while (extent < &s->extents[s->num_extents]) {
>> +        vmdk_debug_print_one_extent(extent);
>> +        extent++;
>> +    }
>> +}
>> +#endif
>> +
>>   static int vmdk_open_desc_file(BlockDriverState *bs, int flags,
>>                                  int64_t desc_offset)
>>   {
>> @@ -728,7 +794,13 @@ static int vmdk_open_desc_file(BlockDriverState *bs,
>> int flags,
>>           return -ENOTSUP;
>>       }
>>       s->desc_offset = 0;
>> -    return vmdk_parse_extents(buf, bs, bs->file->filename);
>> +    ret = vmdk_parse_extents(buf, bs, bs->file->filename);
>> +
>> +#ifdef DEBUG_VMDK
>> +    vmdk_debug_print_extents(bs);
>> +#endif
>> +
>> +    return ret;
>>   }
>>
>>   static int vmdk_open(BlockDriverState *bs, int flags)
>> @@ -774,6 +846,14 @@ static int get_whole_cluster(BlockDriverState *bs,
>>       /* 128 sectors * 512 bytes each = grain size 64KB */
>>       uint8_t  whole_grain[extent->cluster_sectors * 512];
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_get_whole_cluster: filename=%s, cluster_offset=%" PRId64
>> +           ", offset=%" PRId64 "\n",
>> +           extent->file->filename, cluster_offset, offset
>> +           );
>> +#endif
>> +
>>       /* we will be here if it's first write on non-exist grain(cluster).
>>        * try to read from parent image, if exist */
>>       if (bs->backing_hd) {
>> @@ -1032,18 +1112,35 @@ static int vmdk_read_extent(VmdkExtent *extent,
>> int64_t cluster_offset,
>>       VmdkGrainMarker *marker;
>>       uLongf buf_len;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_read_extent: filename=%s, cluster_offset=%" PRId64
>> +           ", offset_in_cluster=%" PRId64 ", nb_sectors=%i\n",
>> +           extent->file->filename, cluster_offset,
>> +           offset_in_cluster, nb_sectors
>> +           );
>> +#endif
>>
>>       if (!extent->compressed) {
>> +
>> +#ifdef DEBUG_VMDK
>> +        printf(DEBUG_VMDK_PREFIX
>> +               "vmdk_read_extent:bdrv_pread filename=%s, offset=%" PRId64
>> +               ", length=%i\n",
>> +               extent->file->filename, offset_in_cluster, nb_sectors << 9
>> +               );
>> +#endif
>> +
>>           ret = bdrv_pread(extent->file,
>>                             cluster_offset + offset_in_cluster,
>> -                          buf, nb_sectors * 512);
>> -        if (ret == nb_sectors * 512) {
>> +                          buf, nb_sectors << 9);
>> +        if (ret == nb_sectors << 9) {
>>               return 0;
>>           } else {
>>               return -EIO;
>>           }
>>       }
>> -    cluster_bytes = extent->cluster_sectors * 512;
>> +    cluster_bytes = extent->cluster_sectors << 9;
>>       /* Read two clusters in case GrainMarker + compressed data > one
>> cluster */
>>       buf_bytes = cluster_bytes * 2;
>>       cluster_buf = g_malloc(buf_bytes);
>> @@ -1092,9 +1189,18 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>       BDRVVmdkState *s = bs->opaque;
>>       int ret;
>>       uint64_t n, index_in_cluster;
>> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>>       VmdkExtent *extent = NULL;
>>       uint64_t cluster_offset;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_read: sectornum=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       while (nb_sectors > 0) {
>>           extent = find_extent(s, sector_num, extent);
>>           if (!extent) {
>> @@ -1103,7 +1209,9 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>           ret = get_cluster_offset(
>>                               bs, extent, NULL,
>>                               sector_num << 9, 0, &cluster_offset);
>> -        index_in_cluster = sector_num % extent->cluster_sectors;
>> +        extent_begin_sector = extent->end_sector - extent->sectors;
>> +        extent_relative_sector_num = sector_num - extent_begin_sector;
>> +        index_in_cluster = extent_relative_sector_num %
>> extent->cluster_sectors;
>>           n = extent->cluster_sectors - index_in_cluster;
>>           if (n > nb_sectors) {
>>               n = nb_sectors;
>> @@ -1119,11 +1227,11 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>                       return ret;
>>                   }
>>               } else {
>> -                memset(buf, 0, 512 * n);
>> +                memset(buf, 0, n << 9);
>>               }
>>           } else {
>>               ret = vmdk_read_extent(extent,
>> -                            cluster_offset, index_in_cluster * 512,
>> +                            cluster_offset, index_in_cluster << 9,
>>                               buf, n);
>>               if (ret) {
>>                   return ret;
>> @@ -1131,7 +1239,7 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>           }
>>           nb_sectors -= n;
>>           sector_num += n;
>> -        buf += n * 512;
>> +        buf += n << 9;
>>       }
>>       return 0;
>>   }
>> @@ -1154,6 +1262,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t
>> sector_num,
>>       VmdkExtent *extent = NULL;
>>       int n, ret;
>>       int64_t index_in_cluster;
>> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>>       uint64_t cluster_offset;
>>       VmdkMetaData m_data;
>>
>> @@ -1196,7 +1305,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t
>> sector_num,
>>           if (ret) {
>>               return -EINVAL;
>>           }
>> -        index_in_cluster = sector_num % extent->cluster_sectors;
>> +        extent_begin_sector = extent->end_sector - extent->sectors;
>> +        extent_relative_sector_num = sector_num - extent_begin_sector;
>> +        index_in_cluster = extent_relative_sector_num %
>> extent->cluster_sectors;
>>           n = extent->cluster_sectors - index_in_cluster;
>>           if (n > nb_sectors) {
>>               n = nb_sectors;
>> --
>> 1.7.11.7
>>
Lei Li - Nov. 9, 2012, 7:38 a.m.
On 11/09/2012 01:12 PM, Fam Zheng wrote:
> Yes, I can confirm the presence of this bug and this is a valid fix.
>
> May I ask where is this kind of vmdk from? Because regularly we see
> extents in identical size.

I guess the regularly extents you see are SPARSE extent in identical size.
This is the FLAT extent, which is preallocated virtual disk.
   

>
> ---
> Best regards!
> Fam Zheng
>
>
> On Fri, Nov 9, 2012 at 3:05 AM, Gerhard Wiesinger <lists@wiesinger.com> wrote:
>> Fixed a MAJOR BUG in VMDK files on file boundaries on reads
>> and ALSO ON WRITES WHICH MIGHT CORRUPT THE IMAGE AND DATA!!!!!!
>>
>> Triggered for example with the following VMDK file (partly listed):
>> # Extent description
>> RW 4193792 FLAT "XP-W1-f001.vmdk" 0
>> RW 2097664 FLAT "XP-W1-f002.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f003.vmdk" 0
>> RW 512 FLAT "XP-W1-f004.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f005.vmdk" 0
>> RW 2097664 FLAT "XP-W1-f006.vmdk" 0
>> RW 4193792 FLAT "XP-W1-f007.vmdk" 0
>> RW 512 FLAT "XP-W1-f008.vmdk" 0
>>
>> Patch includes:
>> 1.) Patch fixes wrong calculation on extent boundaries. Especially it fixes
>> the relativeness of the sector number to the current extent.
>> 2.) Added debug code to block.c and to block/vmdk.c to verify correctness
>> 3.) Also optimized code which avoids multiplication and uses shifts.
>>
>> Verfied correctness with:
>> 1.) Converted either with Virtualbox to VDI and then with qemu-img and then
>> with qemu-img only
>> VBoxManage clonehd --format vdi /VM/XP-W/new/XP-W1.vmdk
>> ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
>> ./qemu-img convert -O raw ~/.VirtualBox/Harddisks/XP-W1-new-test.vdi
>> /root/QEMU/VM-XP-W1/XP-W1-via-VBOX.img
>> md5sum /root/QEMU/VM-XP-W/XP-W1-direct.img
>> md5sum /root/QEMU/VM-XP-W/XP-W1-via-VBOX.img
>> => same MD5 hash
>> 2.) Verified debug log files
>> 3.) Run Windows XP successfully
>> 4.) chkdsk run successfully without any errors
>>
>> Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
>> ---
>>   block.c      |  50 +++++++++++++++++++++++
>>   block/vmdk.c | 129
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
>>   2 files changed, 170 insertions(+), 9 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index da1fdca..69259f2 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -49,6 +49,12 @@
>>   #include <windows.h>
>>   #endif
>>
>> +#if 0
>> +   #define DEBUG_BLOCK
>> +#endif
>> +
>> +#define DEBUG_BLOCK_PREFIX "BLOCK: "
>> +
>>   #define NOT_DONE 0x7fffffff /* used while emulated sync operation in
>> progress */
>>
>>   typedef enum {
>> @@ -789,6 +795,18 @@ int bdrv_open(BlockDriverState *bs, const char
>> *filename, int flags,
>>       int ret;
>>       char tmp_filename[PATH_MAX];
>>
>> +#ifdef DEBUG_BLOCK
>> +    const char *format = "(nil)";
>> +    if (drv) {
>> +        format = drv->format_name;
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_open: filename=%s, BlockDriver=%p, format=%s\n",
>> +           filename, drv, format
>> +           );
>> +#endif
>> +
>>       if (flags & BDRV_O_SNAPSHOT) {
>>           BlockDriverState *bs1;
>>           int64_t total_size;
>> @@ -2004,6 +2022,22 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t
>> sector_num, uint8_t *buf,
>>   int bdrv_read(BlockDriverState *bs, int64_t sector_num,
>>                 uint8_t *buf, int nb_sectors)
>>   {
>> +#ifdef DEBUG_BLOCK
>> +    BlockDriver *drv = bs->drv;
>> +    const char *format_name = "(nil)";
>> +    if (drv) {
>> +        if (drv->format_name) {
>> +            format_name = drv->format_name;
>> +        }
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_read: driver=%s, filename=%s, sector_num=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           format_name, bs->filename, sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
>>   }
>>
>> @@ -2060,6 +2094,22 @@ static void set_dirty_bitmap(BlockDriverState *bs,
>> int64_t sector_num,
>>   int bdrv_write(BlockDriverState *bs, int64_t sector_num,
>>                  const uint8_t *buf, int nb_sectors)
>>   {
>> +#ifdef DEBUG_BLOCK
>> +    BlockDriver *drv = bs->drv;
>> +    const char *format_name = "(nil)";
>> +    if (drv) {
>> +        if (drv->format_name) {
>> +            format_name = drv->format_name;
>> +        }
>> +    }
>> +
>> +    printf(DEBUG_BLOCK
>> +           "bdrv_write: driver=%s, filename=%s, sector_num=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           format_name, bs->filename, sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true);
>>   }
>>
>> diff --git a/block/vmdk.c b/block/vmdk.c
>> index 1a80e5a..92ab92c 100644
>> --- a/block/vmdk.c
>> +++ b/block/vmdk.c
>> @@ -29,6 +29,15 @@
>>   #include "migration.h"
>>   #include <zlib.h>
>>
>> +#if 0
>> +    #define DEBUG_VMDK
>> +#endif
>> +
>> +#define DEBUG_VMDK_PREFIX "VMDK: "
>> +#define DEBUG_VMDK_SEPARATOR \
>> +        "########################################" \
>> +        "########################################"
>> +
>>   #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
>>   #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
>>   #define VMDK4_COMPRESSION_DEFLATE 1
>> @@ -377,6 +386,16 @@ static VmdkExtent *vmdk_add_extent(BlockDriverState
>> *bs,
>>       VmdkExtent *extent;
>>       BDRVVmdkState *s = bs->opaque;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_add_extent: flat=%i, sectors=%" PRId64
>> +           ", l1_backup_offset=%" PRId64
>> +           ", l1_size=%u, l2_size=%i, cluster_sectors=%u\n",
>> +           (int)flat, sectors, l1_backup_offset,
>> +           l1_size, l2_size, cluster_sectors
>> +           );
>> +#endif
>> +
>>       s->extents = g_realloc(s->extents,
>>                                 (s->num_extents + 1) * sizeof(VmdkExtent));
>>       extent = &s->extents[s->num_extents];
>> @@ -674,6 +693,14 @@ static int vmdk_parse_extents(const char *desc,
>> BlockDriverState *bs,
>>               return ret;
>>           }
>>
>> +#ifdef DEBUG_VMDK
>> +        printf(DEBUG_VMDK_PREFIX
>> +               "valid extent found: access=%s, sectors=%" PRId64
>> +               ", type=%s, filename=%s, flat_offset=%" PRId64 "\n",
>> +               access, sectors, type, fname, flat_offset
>> +               );
>> +#endif
>> +
>>           /* save to extents array */
>>           if (!strcmp(type, "FLAT")) {
>>               /* FLAT extent */
>> @@ -704,6 +731,45 @@ next_line:
>>       return 0;
>>   }
>>
>> +#ifdef DEBUG_VMDK
>> +static void vmdk_debug_print_one_extent(VmdkExtent *extent)
>> +{
>> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
>> +    printf(DEBUG_VMDK_PREFIX "filename%s\n", extent->file->filename);
>> +    printf(DEBUG_VMDK_PREFIX "flat=%i\n", (int)extent->flat);
>> +    printf(DEBUG_VMDK_PREFIX "compressed=%i\n", (int)extent->compressed);
>> +    printf(DEBUG_VMDK_PREFIX "has_marker=%i\n", (int)extent->has_marker);
>> +    printf(DEBUG_VMDK_PREFIX "sectors=%" PRId64 "\n", extent->sectors);
>> +    printf(DEBUG_VMDK_PREFIX "end_sector=%" PRId64 "\n",
>> extent->end_sector);
>> +    printf(DEBUG_VMDK_PREFIX "flat_start_offset=%" PRId64 "\n",
>> +                             extent->flat_start_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_table_offsett=%" PRId64 "\n",
>> +                             extent->l1_table_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_backup_table_offsett=%"
>> +                             PRId64 "\n", extent->l1_backup_table_offset);
>> +    printf(DEBUG_VMDK_PREFIX "l1_size=%u\n", extent->l1_size);
>> +    printf(DEBUG_VMDK_PREFIX "l1_entry_sectors=%u\n",
>> extent->l1_entry_sectors);
>> +    printf(DEBUG_VMDK_PREFIX "l2_size=%u\n", extent->l2_size);
>> +    printf(DEBUG_VMDK_PREFIX "cluster_sectors=%u\n",
>> extent->cluster_sectors);
>> +    fflush(stdout);
>> +}
>> +
>> +static void vmdk_debug_print_extents(BlockDriverState *bs)
>> +{
>> +    BDRVVmdkState *s = bs->opaque;
>> +    VmdkExtent *extent = &s->extents[0];
>> +
>> +    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
>> +    printf(DEBUG_VMDK_PREFIX "total_sectors=%" PRId64 "\n",
>> bs->total_sectors);
>> +    printf(DEBUG_VMDK_PREFIX "num_extents=%u\n", s->num_extents);
>> +
>> +    while (extent < &s->extents[s->num_extents]) {
>> +        vmdk_debug_print_one_extent(extent);
>> +        extent++;
>> +    }
>> +}
>> +#endif
>> +
>>   static int vmdk_open_desc_file(BlockDriverState *bs, int flags,
>>                                  int64_t desc_offset)
>>   {
>> @@ -728,7 +794,13 @@ static int vmdk_open_desc_file(BlockDriverState *bs,
>> int flags,
>>           return -ENOTSUP;
>>       }
>>       s->desc_offset = 0;
>> -    return vmdk_parse_extents(buf, bs, bs->file->filename);
>> +    ret = vmdk_parse_extents(buf, bs, bs->file->filename);
>> +
>> +#ifdef DEBUG_VMDK
>> +    vmdk_debug_print_extents(bs);
>> +#endif
>> +
>> +    return ret;
>>   }
>>
>>   static int vmdk_open(BlockDriverState *bs, int flags)
>> @@ -774,6 +846,14 @@ static int get_whole_cluster(BlockDriverState *bs,
>>       /* 128 sectors * 512 bytes each = grain size 64KB */
>>       uint8_t  whole_grain[extent->cluster_sectors * 512];
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_get_whole_cluster: filename=%s, cluster_offset=%" PRId64
>> +           ", offset=%" PRId64 "\n",
>> +           extent->file->filename, cluster_offset, offset
>> +           );
>> +#endif
>> +
>>       /* we will be here if it's first write on non-exist grain(cluster).
>>        * try to read from parent image, if exist */
>>       if (bs->backing_hd) {
>> @@ -1032,18 +1112,35 @@ static int vmdk_read_extent(VmdkExtent *extent,
>> int64_t cluster_offset,
>>       VmdkGrainMarker *marker;
>>       uLongf buf_len;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_read_extent: filename=%s, cluster_offset=%" PRId64
>> +           ", offset_in_cluster=%" PRId64 ", nb_sectors=%i\n",
>> +           extent->file->filename, cluster_offset,
>> +           offset_in_cluster, nb_sectors
>> +           );
>> +#endif
>>
>>       if (!extent->compressed) {
>> +
>> +#ifdef DEBUG_VMDK
>> +        printf(DEBUG_VMDK_PREFIX
>> +               "vmdk_read_extent:bdrv_pread filename=%s, offset=%" PRId64
>> +               ", length=%i\n",
>> +               extent->file->filename, offset_in_cluster, nb_sectors << 9
>> +               );
>> +#endif
>> +
>>           ret = bdrv_pread(extent->file,
>>                             cluster_offset + offset_in_cluster,
>> -                          buf, nb_sectors * 512);
>> -        if (ret == nb_sectors * 512) {
>> +                          buf, nb_sectors << 9);
>> +        if (ret == nb_sectors << 9) {
>>               return 0;
>>           } else {
>>               return -EIO;
>>           }
>>       }
>> -    cluster_bytes = extent->cluster_sectors * 512;
>> +    cluster_bytes = extent->cluster_sectors << 9;
>>       /* Read two clusters in case GrainMarker + compressed data > one
>> cluster */
>>       buf_bytes = cluster_bytes * 2;
>>       cluster_buf = g_malloc(buf_bytes);
>> @@ -1092,9 +1189,18 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>       BDRVVmdkState *s = bs->opaque;
>>       int ret;
>>       uint64_t n, index_in_cluster;
>> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>>       VmdkExtent *extent = NULL;
>>       uint64_t cluster_offset;
>>
>> +#ifdef DEBUG_VMDK
>> +    printf(DEBUG_VMDK_PREFIX
>> +           "vmdk_read: sectornum=%" PRId64
>> +           ", nb_sectors=%i\n",
>> +           sector_num, nb_sectors
>> +           );
>> +#endif
>> +
>>       while (nb_sectors > 0) {
>>           extent = find_extent(s, sector_num, extent);
>>           if (!extent) {
>> @@ -1103,7 +1209,9 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>           ret = get_cluster_offset(
>>                               bs, extent, NULL,
>>                               sector_num << 9, 0, &cluster_offset);
>> -        index_in_cluster = sector_num % extent->cluster_sectors;
>> +        extent_begin_sector = extent->end_sector - extent->sectors;
>> +        extent_relative_sector_num = sector_num - extent_begin_sector;
>> +        index_in_cluster = extent_relative_sector_num %
>> extent->cluster_sectors;
>>           n = extent->cluster_sectors - index_in_cluster;
>>           if (n > nb_sectors) {
>>               n = nb_sectors;
>> @@ -1119,11 +1227,11 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>                       return ret;
>>                   }
>>               } else {
>> -                memset(buf, 0, 512 * n);
>> +                memset(buf, 0, n << 9);
>>               }
>>           } else {
>>               ret = vmdk_read_extent(extent,
>> -                            cluster_offset, index_in_cluster * 512,
>> +                            cluster_offset, index_in_cluster << 9,
>>                               buf, n);
>>               if (ret) {
>>                   return ret;
>> @@ -1131,7 +1239,7 @@ static int vmdk_read(BlockDriverState *bs, int64_t
>> sector_num,
>>           }
>>           nb_sectors -= n;
>>           sector_num += n;
>> -        buf += n * 512;
>> +        buf += n << 9;
>>       }
>>       return 0;
>>   }
>> @@ -1154,6 +1262,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t
>> sector_num,
>>       VmdkExtent *extent = NULL;
>>       int n, ret;
>>       int64_t index_in_cluster;
>> +    uint64_t extent_begin_sector, extent_relative_sector_num;
>>       uint64_t cluster_offset;
>>       VmdkMetaData m_data;
>>
>> @@ -1196,7 +1305,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t
>> sector_num,
>>           if (ret) {
>>               return -EINVAL;
>>           }
>> -        index_in_cluster = sector_num % extent->cluster_sectors;
>> +        extent_begin_sector = extent->end_sector - extent->sectors;
>> +        extent_relative_sector_num = sector_num - extent_begin_sector;
>> +        index_in_cluster = extent_relative_sector_num %
>> extent->cluster_sectors;
>>           n = extent->cluster_sectors - index_in_cluster;
>>           if (n > nb_sectors) {
>>               n = nb_sectors;
>> --
>> 1.7.11.7
>>

Patch

diff --git a/block.c b/block.c
index da1fdca..69259f2 100644
--- a/block.c
+++ b/block.c
@@ -49,6 +49,12 @@ 
  #include <windows.h>
  #endif

+#if 0
+   #define DEBUG_BLOCK
+#endif
+
+#define DEBUG_BLOCK_PREFIX "BLOCK: "
+
  #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */

  typedef enum {
@@ -789,6 +795,18 @@  int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
      int ret;
      char tmp_filename[PATH_MAX];

+#ifdef DEBUG_BLOCK
+    const char *format = "(nil)";
+    if (drv) {
+        format = drv->format_name;
+    }
+
+    printf(DEBUG_BLOCK
+           "bdrv_open: filename=%s, BlockDriver=%p, format=%s\n",
+           filename, drv, format
+           );
+#endif
+
      if (flags & BDRV_O_SNAPSHOT) {
          BlockDriverState *bs1;
          int64_t total_size;
@@ -2004,6 +2022,22 @@  static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
  int bdrv_read(BlockDriverState *bs, int64_t sector_num,
                uint8_t *buf, int nb_sectors)
  {
+#ifdef DEBUG_BLOCK
+    BlockDriver *drv = bs->drv;
+    const char *format_name = "(nil)";
+    if (drv) {
+        if (drv->format_name) {
+            format_name = drv->format_name;
+        }
+    }
+
+    printf(DEBUG_BLOCK
+           "bdrv_read: driver=%s, filename=%s, sector_num=%" PRId64
+           ", nb_sectors=%i\n",
+           format_name, bs->filename, sector_num, nb_sectors
+           );
+#endif
+
      return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
  }

@@ -2060,6 +2094,22 @@  static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
  int bdrv_write(BlockDriverState *bs, int64_t sector_num,
                 const uint8_t *buf, int nb_sectors)
  {
+#ifdef DEBUG_BLOCK
+    BlockDriver *drv = bs->drv;
+    const char *format_name = "(nil)";
+    if (drv) {
+        if (drv->format_name) {
+            format_name = drv->format_name;
+        }
+    }
+
+    printf(DEBUG_BLOCK
+           "bdrv_write: driver=%s, filename=%s, sector_num=%" PRId64
+           ", nb_sectors=%i\n",
+           format_name, bs->filename, sector_num, nb_sectors
+           );
+#endif
+
      return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true);
  }

diff --git a/block/vmdk.c b/block/vmdk.c
index 1a80e5a..92ab92c 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -29,6 +29,15 @@ 
  #include "migration.h"
  #include <zlib.h>

+#if 0
+    #define DEBUG_VMDK
+#endif
+
+#define DEBUG_VMDK_PREFIX "VMDK: "
+#define DEBUG_VMDK_SEPARATOR \
+        "########################################" \
+        "########################################"
+
  #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
  #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
  #define VMDK4_COMPRESSION_DEFLATE 1
@@ -377,6 +386,16 @@  static VmdkExtent *vmdk_add_extent(BlockDriverState *bs,
      VmdkExtent *extent;
      BDRVVmdkState *s = bs->opaque;

+#ifdef DEBUG_VMDK
+    printf(DEBUG_VMDK_PREFIX
+           "vmdk_add_extent: flat=%i, sectors=%" PRId64
+           ", l1_backup_offset=%" PRId64
+           ", l1_size=%u, l2_size=%i, cluster_sectors=%u\n",
+           (int)flat, sectors, l1_backup_offset,
+           l1_size, l2_size, cluster_sectors
+           );
+#endif
+
      s->extents = g_realloc(s->extents,
                                (s->num_extents + 1) * sizeof(VmdkExtent));
      extent = &s->extents[s->num_extents];
@@ -674,6 +693,14 @@  static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
              return ret;
          }

+#ifdef DEBUG_VMDK
+        printf(DEBUG_VMDK_PREFIX
+               "valid extent found: access=%s, sectors=%" PRId64
+               ", type=%s, filename=%s, flat_offset=%" PRId64 "\n",
+               access, sectors, type, fname, flat_offset
+               );
+#endif
+
          /* save to extents array */
          if (!strcmp(type, "FLAT")) {
              /* FLAT extent */
@@ -704,6 +731,45 @@  next_line:
      return 0;
  }

+#ifdef DEBUG_VMDK
+static void vmdk_debug_print_one_extent(VmdkExtent *extent)
+{
+    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
+    printf(DEBUG_VMDK_PREFIX "filename%s\n", extent->file->filename);
+    printf(DEBUG_VMDK_PREFIX "flat=%i\n", (int)extent->flat);
+    printf(DEBUG_VMDK_PREFIX "compressed=%i\n", (int)extent->compressed);
+    printf(DEBUG_VMDK_PREFIX "has_marker=%i\n", (int)extent->has_marker);
+    printf(DEBUG_VMDK_PREFIX "sectors=%" PRId64 "\n", extent->sectors);
+    printf(DEBUG_VMDK_PREFIX "end_sector=%" PRId64 "\n", extent->end_sector);
+    printf(DEBUG_VMDK_PREFIX "flat_start_offset=%" PRId64 "\n",
+                             extent->flat_start_offset);
+    printf(DEBUG_VMDK_PREFIX "l1_table_offsett=%" PRId64 "\n",
+                             extent->l1_table_offset);
+    printf(DEBUG_VMDK_PREFIX "l1_backup_table_offsett=%"
+                             PRId64 "\n", extent->l1_backup_table_offset);
+    printf(DEBUG_VMDK_PREFIX "l1_size=%u\n", extent->l1_size);
+    printf(DEBUG_VMDK_PREFIX "l1_entry_sectors=%u\n", extent->l1_entry_sectors);
+    printf(DEBUG_VMDK_PREFIX "l2_size=%u\n", extent->l2_size);
+    printf(DEBUG_VMDK_PREFIX "cluster_sectors=%u\n", extent->cluster_sectors);
+    fflush(stdout);
+}
+
+static void vmdk_debug_print_extents(BlockDriverState *bs)
+{
+    BDRVVmdkState *s = bs->opaque;
+    VmdkExtent *extent = &s->extents[0];
+
+    printf(DEBUG_VMDK_PREFIX DEBUG_VMDK_SEPARATOR "\n");
+    printf(DEBUG_VMDK_PREFIX "total_sectors=%" PRId64 "\n", bs->total_sectors);
+    printf(DEBUG_VMDK_PREFIX "num_extents=%u\n", s->num_extents);
+
+    while (extent < &s->extents[s->num_extents]) {
+        vmdk_debug_print_one_extent(extent);
+        extent++;
+    }
+}
+#endif
+
  static int vmdk_open_desc_file(BlockDriverState *bs, int flags,
                                 int64_t desc_offset)
  {
@@ -728,7 +794,13 @@  static int vmdk_open_desc_file(BlockDriverState *bs, int flags,
          return -ENOTSUP;
      }
      s->desc_offset = 0;
-    return vmdk_parse_extents(buf, bs, bs->file->filename);
+    ret = vmdk_parse_extents(buf, bs, bs->file->filename);
+
+#ifdef DEBUG_VMDK
+    vmdk_debug_print_extents(bs);
+#endif
+
+    return ret;
  }

  static int vmdk_open(BlockDriverState *bs, int flags)
@@ -774,6 +846,14 @@  static int get_whole_cluster(BlockDriverState *bs,
      /* 128 sectors * 512 bytes each = grain size 64KB */
      uint8_t  whole_grain[extent->cluster_sectors * 512];

+#ifdef DEBUG_VMDK
+    printf(DEBUG_VMDK_PREFIX
+           "vmdk_get_whole_cluster: filename=%s, cluster_offset=%" PRId64
+           ", offset=%" PRId64 "\n",
+           extent->file->filename, cluster_offset, offset
+           );
+#endif
+
      /* we will be here if it's first write on non-exist grain(cluster).
       * try to read from parent image, if exist */
      if (bs->backing_hd) {
@@ -1032,18 +1112,35 @@  static int vmdk_read_extent(VmdkExtent *extent, int64_t cluster_offset,
      VmdkGrainMarker *marker;
      uLongf buf_len;

+#ifdef DEBUG_VMDK
+    printf(DEBUG_VMDK_PREFIX
+           "vmdk_read_extent: filename=%s, cluster_offset=%" PRId64
+           ", offset_in_cluster=%" PRId64 ", nb_sectors=%i\n",
+           extent->file->filename, cluster_offset,
+           offset_in_cluster, nb_sectors
+           );
+#endif

      if (!extent->compressed) {
+
+#ifdef DEBUG_VMDK
+        printf(DEBUG_VMDK_PREFIX
+               "vmdk_read_extent:bdrv_pread filename=%s, offset=%" PRId64
+               ", length=%i\n",
+               extent->file->filename, offset_in_cluster, nb_sectors << 9
+               );
+#endif
+
          ret = bdrv_pread(extent->file,
                            cluster_offset + offset_in_cluster,
-                          buf, nb_sectors * 512);
-        if (ret == nb_sectors * 512) {
+                          buf, nb_sectors << 9);
+        if (ret == nb_sectors << 9) {
              return 0;
          } else {
              return -EIO;
          }
      }
-    cluster_bytes = extent->cluster_sectors * 512;
+    cluster_bytes = extent->cluster_sectors << 9;
      /* Read two clusters in case GrainMarker + compressed data > one cluster */
      buf_bytes = cluster_bytes * 2;
      cluster_buf = g_malloc(buf_bytes);
@@ -1092,9 +1189,18 @@  static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
      BDRVVmdkState *s = bs->opaque;
      int ret;
      uint64_t n, index_in_cluster;
+    uint64_t extent_begin_sector, extent_relative_sector_num;
      VmdkExtent *extent = NULL;
      uint64_t cluster_offset;

+#ifdef DEBUG_VMDK
+    printf(DEBUG_VMDK_PREFIX
+           "vmdk_read: sectornum=%" PRId64
+           ", nb_sectors=%i\n",
+           sector_num, nb_sectors
+           );
+#endif
+
      while (nb_sectors > 0) {
          extent = find_extent(s, sector_num, extent);
          if (!extent) {
@@ -1103,7 +1209,9 @@  static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
          ret = get_cluster_offset(
                              bs, extent, NULL,
                              sector_num << 9, 0, &cluster_offset);
-        index_in_cluster = sector_num % extent->cluster_sectors;
+        extent_begin_sector = extent->end_sector - extent->sectors;
+        extent_relative_sector_num = sector_num - extent_begin_sector;
+        index_in_cluster = extent_relative_sector_num % extent->cluster_sectors;
          n = extent->cluster_sectors - index_in_cluster;
          if (n > nb_sectors) {
              n = nb_sectors;
@@ -1119,11 +1227,11 @@  static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
                      return ret;
                  }
              } else {
-                memset(buf, 0, 512 * n);
+                memset(buf, 0, n << 9);
              }
          } else {
              ret = vmdk_read_extent(extent,
-                            cluster_offset, index_in_cluster * 512,
+                            cluster_offset, index_in_cluster << 9,
                              buf, n);
              if (ret) {
                  return ret;
@@ -1131,7 +1239,7 @@  static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
          }
          nb_sectors -= n;
          sector_num += n;
-        buf += n * 512;
+        buf += n << 9;
      }
      return 0;
  }
@@ -1154,6 +1262,7 @@  static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
      VmdkExtent *extent = NULL;
      int n, ret;
      int64_t index_in_cluster;
+    uint64_t extent_begin_sector, extent_relative_sector_num;
      uint64_t cluster_offset;
      VmdkMetaData m_data;

@@ -1196,7 +1305,9 @@  static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
          if (ret) {
              return -EINVAL;
          }
-        index_in_cluster = sector_num % extent->cluster_sectors;
+        extent_begin_sector = extent->end_sector - extent->sectors;
+        extent_relative_sector_num = sector_num - extent_begin_sector;
+        index_in_cluster = extent_relative_sector_num % extent->cluster_sectors;
          n = extent->cluster_sectors - index_in_cluster;
          if (n > nb_sectors) {
              n = nb_sectors;