nbd: Switch to byte-based block access
Sector-based blk_read() should die; switch to byte-based
blk_pread() instead.
Add a constant for our magic number 512, to make it obvious
that this size will NOT change even if BDRV_SECTOR_SIZE does,
even though the two happen to be the same for now. Split
assignments from conditionals to keep checkpatch.pl happy.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-nbd.c b/qemu-nbd.c
index c55b40f..3e54113 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -46,6 +46,8 @@
#define QEMU_NBD_OPT_TLSCREDS 261
#define QEMU_NBD_OPT_IMAGE_OPTS 262
+#define MBR_SIZE 512
+
static NBDExport *exp;
static bool newproto;
static int verbose;
@@ -159,12 +161,13 @@
off_t *offset, off_t *size)
{
struct partition_record mbr[4];
- uint8_t data[512];
+ uint8_t data[MBR_SIZE];
int i;
int ext_partnum = 4;
int ret;
- if ((ret = blk_read(blk, 0, data, 1)) < 0) {
+ ret = blk_pread(blk, 0, data, sizeof(data));
+ if (ret < 0) {
error_report("error while reading: %s", strerror(-ret));
exit(EXIT_FAILURE);
}
@@ -182,10 +185,12 @@
if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
struct partition_record ext[4];
- uint8_t data1[512];
+ uint8_t data1[MBR_SIZE];
int j;
- if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) {
+ ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE,
+ data1, sizeof(data1));
+ if (ret < 0) {
error_report("error while reading: %s", strerror(-ret));
exit(EXIT_FAILURE);
}
