Patchwork [RFC,04/24] block: add bdrv_get_mapping()

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Submitter Devin Nakamura
Date July 29, 2011, 4:49 a.m.
Message ID <1311914994-20482-5-git-send-email-devin122@gmail.com>
Download mbox | patch
Permalink /patch/107353/
State New
Headers show

Comments

Devin Nakamura - July 29, 2011, 4:49 a.m.
Conflicts:

	block.h

Signed-off-by: Devin Nakamura <devin122@gmail.com>
---
 block.c |   29 +++++++++++++++++++++++++++++
 block.h |    2 ++
 2 files changed, 31 insertions(+), 0 deletions(-)
Stefan Hajnoczi - Aug. 2, 2011, 8:58 a.m.
On Fri, Jul 29, 2011 at 12:49:34AM -0400, Devin Nakamura wrote:
> +/**
> + * Gets a mapping from an offset in the image to an offset within a file
> + *
> + * All offsets are in bytes. Functions starts its search at offset host_offset
> + * + count (offset within the image, not the file offset)

This function starts its search at *guest_offset + *contiguous_bytes.

> + *
> + * @param guest_offset          used to calculate starting search location on

[in, out]

Stefan

Patch

diff --git a/block.c b/block.c
index 9530577..d0019c4 100644
--- a/block.c
+++ b/block.c
@@ -3082,3 +3082,32 @@  int bdrv_get_conversion_options(BlockDriverState *bs,
     }
     return bs->drv->bdrv_get_conversion_options(bs, options);
 }
+
+/**
+ * Gets a mapping from an offset in the image to an offset within a file
+ *
+ * All offsets are in bytes. Functions starts its search at offset host_offset
+ * + count (offset within the image, not the file offset)
+ *
+ * @param guest_offset          used to calculate starting search location on
+ *                              function call. On return it is the starting
+ *                              offset of the mapping in the image.
+ * @param host_offset[out]      The starting file offset of the mapping.
+ * @param contiguous_bytes[out] The number of bytes for which this mapping is
+ *                              contiguous. If 0, there are no more mapppings in
+ *                              the image
+ */
+
+int bdrv_get_mapping(BlockDriverState *bs, uint64_t *guest_offset,
+                     uint64_t *host_offset, uint64_t *contiguous_bytes)
+{
+    BlockDriver *drv = bs->drv;
+    if (!drv) {
+        return -ENOMEDIUM;
+    }
+    if (!drv->bdrv_get_mapping) {
+        return -ENOTSUP;
+    }
+    return drv->bdrv_get_mapping(bs, guest_offset, host_offset,
+        contiguous_bytes);
+}
diff --git a/block.h b/block.h
index 662bae7..3459900 100644
--- a/block.h
+++ b/block.h
@@ -259,6 +259,8 @@  int bdrv_open_conversion_target(BlockDriverState **bs, BlockDriverState *file,
                                 BlockConversionOptions *drv_options,
                                 QEMUOptionParameter *usr_options,
                                 const char *target_fmt);
+int bdrv_get_mapping(BlockDriverState *bs, uint64_t *guest_offset,
+                     uint64_t *host_offset, uint64_t *contiguous_bytes);
 typedef enum {
     BLKDBG_L1_UPDATE,