[Qemu-devel] [RFC V2 11/20] qcow2: Load and save deduplication table header extension.

["Benoît Canet" <benoit@irqsave.net>]

---
 block/qcow2.c |   35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index c1ff31f..18cb85d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -53,9 +53,15 @@ typedef struct {
     uint32_t len;
 } QCowExtension;
 
+typedef struct {
+    uint64_t offset;
+    int32_t  size;
+} QCowDedupTableExtension;
+
 #define  QCOW2_EXT_MAGIC_END 0
 #define  QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
 #define  QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
+#define  QCOW2_EXT_MAGIC_DEDUP_TABLE 0xCD8E819B
 
 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
@@ -84,6 +90,7 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
     QCowExtension ext;
     uint64_t offset;
     int ret;
+    QCowDedupTableExtension dedup_table_extension;
 
 #ifdef DEBUG_EXT
     printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
@@ -148,6 +155,18 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
             }
             break;
 
+        case QCOW2_EXT_MAGIC_DEDUP_TABLE:
+                ret = bdrv_pread(bs->file, offset,
+                                 &dedup_table_extension, ext.len);
+                if (ret < 0) {
+                    return ret;
+                }
+                s->dedup_table_offset =
+                    be64_to_cpu(dedup_table_extension.offset);
+                s->dedup_table_size =
+                    be32_to_cpu(dedup_table_extension.size);
+            break;
+
         default:
             /* unknown magic - save it in case we need to rewrite the header */
             {
@@ -964,6 +983,7 @@ int qcow2_update_header(BlockDriverState *bs)
     uint32_t refcount_table_clusters;
     size_t header_length;
     Qcow2UnknownHeaderExtension *uext;
+    QCowDedupTableExtension dedup_table_extension;
 
     buf = qemu_blockalign(bs, buflen);
 
@@ -1067,6 +1087,21 @@ int qcow2_update_header(BlockDriverState *bs)
     buf += ret;
     buflen -= ret;
 
+    if (s->has_dedup) {
+        dedup_table_extension.offset = cpu_to_be64(s->dedup_table_offset);
+        dedup_table_extension.size = cpu_to_be32(s->dedup_table_size);
+        ret = header_ext_add(buf,
+                             QCOW2_EXT_MAGIC_DEDUP_TABLE,
+                             &dedup_table_extension,
+                             sizeof(dedup_table_extension),
+                             buflen);
+        if (ret < 0) {
+            goto fail;
+        }
+        buf += ret;
+        buflen -= ret;
+    }
+
     /* Keep unknown header extensions */
     QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
         ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
-- 
1.7.10.4