block: add bdrv functions for geometry and blocksize

Add driver functions for geometry and blocksize detection

Signed-off-by: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1424087278-49393-2-git-send-email-tumanova@linux.vnet.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -568,6 +568,40 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
     }
 }
 
+/**
+ * Try to get @bs's logical and physical block size.
+ * On success, store them in @bsz struct and return 0.
+ * On failure return -errno.
+ * @bs must not be empty.
+ */
+int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
+{
+    BlockDriver *drv = bs->drv;
+
+    if (drv && drv->bdrv_probe_blocksizes) {
+        return drv->bdrv_probe_blocksizes(bs, bsz);
+    }
+
+    return -ENOTSUP;
+}
+
+/**
+ * Try to get @bs's geometry (cyls, heads, sectors).
+ * On success, store them in @geo struct and return 0.
+ * On failure return -errno.
+ * @bs must not be empty.
+ */
+int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
+{
+    BlockDriver *drv = bs->drv;
+
+    if (drv && drv->bdrv_probe_geometry) {
+        return drv->bdrv_probe_geometry(bs, geo);
+    }
+
+    return -ENOTSUP;
+}
+
 /*
  * Create a uniquely-named empty temporary file.
  * Return 0 upon success, otherwise a negative errno value.

include/block/block.h

@@ -60,6 +60,17 @@ typedef enum {
     BDRV_REQ_MAY_UNMAP    = 0x4,
 } BdrvRequestFlags;
 
+typedef struct BlockSizes {
+    uint32_t phys;
+    uint32_t log;
+} BlockSizes;
+
+typedef struct HDGeometry {
+    uint32_t heads;
+    uint32_t sectors;
+    uint32_t cylinders;
+} HDGeometry;
+
 #define BDRV_O_RDWR        0x0002
 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
@@ -550,6 +561,8 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs);
  * This function must be called with iothread lock held.
  */
 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
+int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
+int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 
 void bdrv_io_plug(BlockDriverState *bs);
 void bdrv_io_unplug(BlockDriverState *bs);

include/block/block_int.h

@@ -275,6 +275,21 @@ struct BlockDriver {
     void (*bdrv_io_unplug)(BlockDriverState *bs);
     void (*bdrv_flush_io_queue)(BlockDriverState *bs);
 
+    /**
+     * Try to get @bs's logical and physical block size.
+     * On success, store them in @bsz and return zero.
+     * On failure, return negative errno.
+     */
+    int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz);
+    /**
+     * Try to get @bs's geometry (cyls, heads, sectors)
+     * On success, store them in @geo and return 0.
+     * On failure return -errno.
+     * Only drivers that want to override guest geometry implement this
+     * callback; see hd_geometry_guess().
+     */
+    int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
+
     QLIST_ENTRY(BlockDriver) list;
 };