[Qemu-devel] [RFC V7 15/32] qcow2: Load and save deduplication table header extension.

["Benoît Canet" <benoit@irqsave.net>]

Signed-off-by: Benoit Canet <benoit@irqsave.net>
---
 block/qcow2.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index ca38cc3..eaddcb6 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -53,9 +53,18 @@ typedef struct {
     uint32_t len;
 } QCowExtension;
 
+typedef struct {
+    uint64_t offset;
+    int32_t  size;
+    uint8_t  hash_algo;
+    uint8_t  strategies;
+    char     reserved[56];
+} 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 +93,7 @@ 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 +158,25 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
             }
             break;
 
+        case QCOW2_EXT_MAGIC_DEDUP_TABLE:
+            if (ext.len > sizeof(dedup_table_extension)) {
+                fprintf(stderr, "ERROR: dedup_table_extension: len=%u too large"
+                        " (>=%zu)\n",
+                        ext.len, sizeof(dedup_table_extension));
+                return 2;
+            }
+            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);
+            s->dedup_hash_algo = dedup_table_extension.hash_algo;
+            break;
+
         default:
             /* unknown magic - save it in case we need to rewrite the header */
             {
@@ -959,6 +988,7 @@ 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);
 
@@ -1062,6 +1092,25 @@ int qcow2_update_header(BlockDriverState *bs)
     buf += ret;
     buflen -= ret;
 
+    if (s->has_dedup) {
+        memset(&dedup_table_extension, 0, sizeof(dedup_table_extension));
+        dedup_table_extension.offset = cpu_to_be64(s->dedup_table_offset);
+        dedup_table_extension.size = cpu_to_be32(s->dedup_table_size);
+        dedup_table_extension.hash_algo = s->dedup_hash_algo;
+        dedup_table_extension.strategies |= QCOW_DEDUP_STRATEGY_RAM;
+        dedup_table_extension.strategies |= QCOW_DEDUP_STRATEGY_RUNNING;
+        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