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block/vpc: Use the correct max sector count for VHD images 

The old VHD_MAX_SECTORS value is incorrect, and is a throwback
to the CHS calculations.  The VHD specification allows images up to 2040
GiB, which (using 512 byte sectors) corresponds to a maximum number of
sectors of 0xff000000, rather than the old value of 0xfe0001ff.

Update VHD_MAX_SECTORS to reflect the correct value.

Also, update comment references to the actual size limit, and correct
one compare so that we can have sizes up to the limit.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Jeff Cody 2016-03-22 23:33:41 -04:00 committed by Kevin Wolf
parent bab246db1d
commit c23fb11bbb
1 changed files with 5 additions and 5 deletions
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10
block/vpc.c
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@ -52,7 +52,7 @@ enum vhd_type {
#define VHD_CHS_MAX_H 16 #define VHD_CHS_MAX_H 16
#define VHD_CHS_MAX_S 255 #define VHD_CHS_MAX_S 255
#define VHD_MAX_SECTORS (65535LL * 255 * 255) #define VHD_MAX_SECTORS 0xff000000 /* 2040 GiB max image size */
#define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S) #define VHD_MAX_GEOMETRY (VHD_CHS_MAX_C * VHD_CHS_MAX_H * VHD_CHS_MAX_S)
#define VPC_OPT_FORCE_SIZE "force_size" #define VPC_OPT_FORCE_SIZE "force_size"
@ -317,8 +317,8 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
BDRV_SECTOR_SIZE; BDRV_SECTOR_SIZE;
} }
/* Allow a maximum disk size of approximately 2 TB */ /* Allow a maximum disk size of 2040 GiB */
if (bs->total_sectors >= VHD_MAX_SECTORS) { if (bs->total_sectors > VHD_MAX_SECTORS) {
ret = -EFBIG; ret = -EFBIG;
goto fail; goto fail;
} }
@ -722,7 +722,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
* Note that the geometry doesn't always exactly match total_sectors but * Note that the geometry doesn't always exactly match total_sectors but
* may round it down. * may round it down.
* *
* Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override * Returns 0 on success, -EFBIG if the size is larger than 2040 GiB. Override
* the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB) * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
* and instead allow up to 255 heads. * and instead allow up to 255 heads.
*/ */
@ -927,7 +927,7 @@ static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) { if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
total_sectors = total_size / BDRV_SECTOR_SIZE; total_sectors = total_size / BDRV_SECTOR_SIZE;
/* Allow a maximum disk size of approximately 2 TB */ /* Allow a maximum disk size of 2040 GiB */
if (total_sectors > VHD_MAX_SECTORS) { if (total_sectors > VHD_MAX_SECTORS) {
error_setg(errp, "Disk size is too large, max size is 2040 GiB"); error_setg(errp, "Disk size is too large, max size is 2040 GiB");
ret = -EFBIG; ret = -EFBIG;