[Qemu-devel] [RFC 01/24] block: add block conversion api

[Devin Nakamura <devin122@gmail.com>]

add functions to block driver interface to support inplace image conversion

Signed-off-by: Devin Nakamura <devin122@gmail.com>
---
 block.h     |    2 +
 block_int.h |   88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+), 0 deletions(-)

diff --git a/block.h b/block.h
index 59cc410..a1c4cc8 100644
--- a/block.h
+++ b/block.h
@@ -251,6 +251,8 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs);
 void bdrv_set_in_use(BlockDriverState *bs, int in_use);
 int bdrv_in_use(BlockDriverState *bs);
 
+typedef struct BlockConversionOptions BlockConversionOptions;
+
 typedef enum {
     BLKDBG_L1_UPDATE,
 
diff --git a/block_int.h b/block_int.h
index efb6803..84bf89e 100644
--- a/block_int.h
+++ b/block_int.h
@@ -41,6 +41,9 @@
 #define BLOCK_OPT_PREALLOC      "preallocation"
 #define BLOCK_OPT_SUBFMT        "subformat"
 
+#define BLOCK_CRYPT_NONE    0
+#define BLOCK_CRYPT_AES     1
+
 typedef struct AIOPool {
     void (*cancel)(BlockDriverAIOCB *acb);
     int aiocb_size;
@@ -139,6 +142,85 @@ struct BlockDriver {
      */
     int (*bdrv_has_zero_init)(BlockDriverState *bs);
 
+    /* In-place image conversion */
+
+    /**
+     * Opens an image conversion target.
+     *
+     * @param bs          Basic Initialization done by
+     *                    bdrv_open_conversion_target() Still need to set format
+     *                    specific data.
+     * @param usr_options Creation options.
+     * @param drv_options Conversion Options
+     * @return            Returns non-zero on failure.
+     */
+    int (*bdrv_open_conversion_target)(BlockDriverState *bs,
+        BlockConversionOptions *drv_options, QEMUOptionParameter *usr_options);
+
+    /**
+     * Gets a mapping in the image file.
+     *
+     * The function starts searching for a mapping at
+     * starting_guest_offset = guest_offset + contiguous_bytes
+     *
+     * @param bs[in]                   The image in which to find mapping.
+     * @param guest_offset[in,out]     On function entry used to calculate
+     *                                 starting search address.
+     *                                 On function exit contains the starting
+     *                                 guest offset of the mapping.
+     * @param host_offset[out]         The starting image file offset for the
+     *                                 mapping.
+     * @param contiguous_bytes[in,out] On function entry used to calculate
+     *                                 starting search address.
+     *                                 On function exit contains the number of
+     *                                 bytes for which this mapping is valid.
+     *                                 A value of 0 means there are no more
+     *                                 mappings in the image.
+     * @return                         Returns non-zero on error.
+     */
+    int (*bdrv_get_mapping)(BlockDriverState *bs, uint64_t *guest_offset,
+        uint64_t *host_offset, uint64_t *contiguous_bytes);
+
+    /**
+     * Sets a mapping in the image file.
+     *
+     * @param bs               Usualy opened with bdrv_open_conversion_target
+     * @param guest_offset     The starting guest offset of the mapping
+     *                         (in bytes). Function fails and returns -EINVAL if
+     *                         not cluster aligned.
+     * @param host_offset      The starting image offset of the mapping
+     *                         (in bytes). Function fails and returns -EINVAL if
+     *                         not cluster aligned.
+     * @param contiguous_bytes The number of bytes for which this mapping exists
+     *                         Function fails and returns -EINVAL if not cluster
+     *                         aligned
+     * @return                 Returns non-zero on error
+     */
+    int (*bdrv_map)(BlockDriverState *bs, uint64_t guest_offset,
+        uint64_t host_offset, uint64_t contiguous_bytes);
+
+    /**
+     * Copies out the header of a conversion target
+     *
+     * Saves the current header for the image in a temporary file and overwrites
+     * it with the header for the new format (at the moment the header is
+     * assumed to be 1 sector)
+     *
+     * @param bs  Usualy opened with bdrv_open_conversion_target().
+     * @return    Returns non-zero on failure
+     */
+    int (*bdrv_copy_header) (BlockDriverState *bs);
+
+    /**
+     * Asks the block driver what options should be used to create a conversion
+     * target.
+     *
+     * @param options[out] Block conversion options
+     */
+    int (*bdrv_get_conversion_options)(BlockDriverState *bs,
+         BlockConversionOptions *options);
+
+
     QLIST_ENTRY(BlockDriver) list;
 };
 
@@ -263,4 +345,10 @@ static inline unsigned int get_physical_block_exp(BlockConf *conf)
     DEFINE_PROP_UINT32("discard_granularity", _state, \
                        _conf.discard_granularity, 0)
 
+struct BlockConversionOptions {
+    int encryption_type;
+    uint64_t image_size;
+    uint64_t cluster_size;
+    uint64_t allocation_size;
+};
 #endif /* BLOCK_INT_H */
-- 
1.7.6.rc1