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Diffstat (limited to 'block.c')
-rw-r--r--block.c24
1 files changed, 17 insertions, 7 deletions
diff --git a/block.c b/block.c
index f2540b9e0c..b410ed6467 100644
--- a/block.c
+++ b/block.c
@@ -1639,6 +1639,20 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
}
+/* Just like bdrv_read(), but with I/O throttling temporarily disabled */
+int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ bool enabled;
+ int ret;
+
+ enabled = bs->io_limits_enabled;
+ bs->io_limits_enabled = false;
+ ret = bdrv_read(bs, 0, buf, 1);
+ bs->io_limits_enabled = enabled;
+ return ret;
+}
+
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
@@ -2136,11 +2150,10 @@ static int guess_disk_lchs(BlockDriverState *bs,
int *pcylinders, int *pheads, int *psectors)
{
uint8_t buf[BDRV_SECTOR_SIZE];
- int ret, i, heads, sectors, cylinders;
+ int i, heads, sectors, cylinders;
struct partition *p;
uint32_t nr_sects;
uint64_t nb_sectors;
- bool enabled;
bdrv_get_geometry(bs, &nb_sectors);
@@ -2149,12 +2162,9 @@ static int guess_disk_lchs(BlockDriverState *bs,
* but also in async I/O mode. So the I/O throttling function has to
* be disabled temporarily here, not permanently.
*/
- enabled = bs->io_limits_enabled;
- bs->io_limits_enabled = false;
- ret = bdrv_read(bs, 0, buf, 1);
- bs->io_limits_enabled = enabled;
- if (ret < 0)
+ if (bdrv_read_unthrottled(bs, 0, buf, 1) < 0) {
return -1;
+ }
/* test msdos magic */
if (buf[510] != 0x55 || buf[511] != 0xaa)
return -1;