diff options
| author | Stefan Weil <weil@mail.berlios.de> | 2010-05-10 21:46:26 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2010-05-17 10:20:05 +0200 |
| commit | dede4188cc817a039154ed2ecd7f3285f6b94056 (patch) | |
| tree | feb149a637b87e6c655eddeead53d243ad6c3c77 /block/vpc.c | |
| parent | 1dec5a70973bde6138d7cf30e98e12a49397abf4 (diff) | |
block/vpc: Fix conversion from size to disk geometry
The VHD algorithm calculates a disk geometry
which is usually smaller than the requested size.
QEMU tried to round up but failed for certain sizes:
qemu-img create -f vpc disk.vpc 9437184
would create an image with 9435136 bytes
(which is too small for qemu-img convert).
Instead of hacking the geometry algorithm, the patch
increases the number of sectors until we get enough
sectors.
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/vpc.c')
| -rw-r--r-- | block/vpc.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/block/vpc.c b/block/vpc.c index f94e4698b7..214e9d121f 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -463,9 +463,7 @@ static int calculate_geometry(int64_t total_sectors, uint16_t* cyls, } } - // Note: Rounding up deviates from the Virtual PC behaviour - // However, we need this to avoid truncating images in qemu-img convert - *cyls = (cyls_times_heads + *heads - 1) / *heads; + *cyls = cyls_times_heads / *heads; return 0; } @@ -477,9 +475,9 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options) struct vhd_dyndisk_header* dyndisk_header = (struct vhd_dyndisk_header*) buf; int fd, i; - uint16_t cyls; - uint8_t heads; - uint8_t secs_per_cyl; + uint16_t cyls = 0; + uint8_t heads = 0; + uint8_t secs_per_cyl = 0; size_t block_size, num_bat_entries; int64_t total_sectors = 0; @@ -496,9 +494,14 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options) if (fd < 0) return -EIO; - // Calculate matching total_size and geometry - if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl)) - return -EFBIG; + /* Calculate matching total_size and geometry. Increase the number of + sectors requested until we get enough (or fail). */ + for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) { + if (calculate_geometry(total_sectors + i, + &cyls, &heads, &secs_per_cyl)) { + return -EFBIG; + } + } total_sectors = (int64_t) cyls * heads * secs_per_cyl; // Prepare the Hard Disk Footer |