Patchwork [RFC,09/24] qed: add qed_bdrv_get_mapping()

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Submitter Devin Nakamura
Date July 29, 2011, 4:49 a.m.
Message ID <1311914994-20482-10-git-send-email-devin122@gmail.com>
Download mbox | patch
Permalink /patch/107338/
State New
Headers show

Comments

Devin Nakamura - July 29, 2011, 4:49 a.m.
Fuction to get drive mapping from qed images

Signed-off-by: Devin Nakamura <devin122@gmail.com>
---
 block/qed.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)
Stefan Hajnoczi - Aug. 2, 2011, 8:59 a.m.
On Fri, Jul 29, 2011 at 12:49:39AM -0400, Devin Nakamura wrote:
> +static int bdrv_qed_get_mapping(BlockDriverState *bs, uint64_t *guest_offset,
> +                                uint64_t *host_offset,
> +                                uint64_t *contiguous_bytes)
> +{
> +    BDRVQEDState *s = bs->opaque;
> +    size_t l2_size = s->header.cluster_size * s->table_nelems;
> +    uint64_t pos = *guest_offset + *contiguous_bytes;
> +    uint64_t offset = pos;
> +    size_t len = 0;
> +    QEDRequest req = {.l2_table = NULL};
> +    int ret;
> +
> +    if (pos >= s->header.image_size) {
> +        *contiguous_bytes = 0;
> +        return 0;
> +    }
> +
> +    do {
> +        pos += len;
> +        ret = qed_find_cluster_sync(s, &req, pos, l2_size, &offset, &len);
> +    } while (ret != QED_CLUSTER_FOUND && pos < s->header.image_size);

qed_unref_l2_cache_entry(request.l2_table);

Stefan

Patch

diff --git a/block/qed.c b/block/qed.c
index 00cf895..dadb7f8 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1451,6 +1451,37 @@  static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result)
     return qed_check(s, result, false);
 }
 
+static int bdrv_qed_get_mapping(BlockDriverState *bs, uint64_t *guest_offset,
+                                uint64_t *host_offset,
+                                uint64_t *contiguous_bytes)
+{
+    BDRVQEDState *s = bs->opaque;
+    size_t l2_size = s->header.cluster_size * s->table_nelems;
+    uint64_t pos = *guest_offset + *contiguous_bytes;
+    uint64_t offset = pos;
+    size_t len = 0;
+    QEDRequest req = {.l2_table = NULL};
+    int ret;
+
+    if (pos >= s->header.image_size) {
+        *contiguous_bytes = 0;
+        return 0;
+    }
+
+    do {
+        pos += len;
+        ret = qed_find_cluster_sync(s, &req, pos, l2_size, &offset, &len);
+    } while (ret != QED_CLUSTER_FOUND && pos < s->header.image_size);
+    *guest_offset = pos;
+    *host_offset = offset;
+    if (pos >= s->header.image_size) {
+        *contiguous_bytes = 0;
+    } else {
+        *contiguous_bytes = len;
+    }
+    return 0;
+}
+
 static QEMUOptionParameter qed_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -1497,6 +1528,7 @@  static BlockDriver bdrv_qed = {
     .bdrv_get_info            = bdrv_qed_get_info,
     .bdrv_change_backing_file = bdrv_qed_change_backing_file,
     .bdrv_check               = bdrv_qed_check,
+    .bdrv_get_mapping         = bdrv_qed_get_mapping,
 };
 
 static void bdrv_qed_init(void)