block-qcow2: export highest_allocated through BlockDriverInfo and get_info() (Uri...

[qemu.git] / block-qcow2.c

diff --git a/block-qcow2.c b/block-qcow2.c
index d4556efa4e9722834ff0ed557b638a3d44122681..7c00ee840b9d952e177168b2e89ed6d24009b106 100644 (file)
--- a/block-qcow2.c
+++ b/block-qcow2.c
@@ -143,6 +143,9 @@ typedef struct BDRVQcowState {
     uint32_t crypt_method_header;
     AES_KEY aes_encrypt_key;
     AES_KEY aes_decrypt_key;
+
+    int64_t highest_alloc; /* highest cluester allocated (in clusters) */
+
     uint64_t snapshots_offset;
     int snapshots_size;
     int nb_snapshots;
@@ -170,6 +173,8 @@ static void free_clusters(BlockDriverState *bs,
 #ifdef DEBUG_ALLOC
 static void check_refcounts(BlockDriverState *bs);
 #endif
+static void scan_refcount(BlockDriverState *bs, int64_t *high);
+
 
 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
@@ -278,6 +283,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
     if (refcount_init(bs) < 0)
         goto fail;
 
+    scan_refcount(bs, &s->highest_alloc);
+
     /* read the backing file name */
     if (header.backing_file_offset != 0) {
         len = header.backing_file_size;
@@ -1664,6 +1671,7 @@ static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     bdi->cluster_size = s->cluster_size;
     bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
         (s->cluster_bits + s->l2_bits);
+    bdi->highest_alloc = s->highest_alloc << s->cluster_bits;
     return 0;
 }
 
@@ -2206,6 +2214,29 @@ static int load_refcount_block(BlockDriverState *bs,
     return 0;
 }
 
+static void scan_refcount(BlockDriverState *bs, int64_t *high)
+{
+    BDRVQcowState *s = bs->opaque;
+    int64_t refcnt_index, cluster_index, cluster_end, h = 0;
+
+    for (refcnt_index=0; refcnt_index < s->refcount_table_size; refcnt_index++){
+        if (s->refcount_table[refcnt_index] == 0) {
+            continue;
+        }
+        cluster_index = refcnt_index << (s->cluster_bits - REFCOUNT_SHIFT);
+        cluster_end = (refcnt_index + 1) << (s->cluster_bits - REFCOUNT_SHIFT);
+        for ( ; cluster_index < cluster_end; cluster_index++) {
+            if (get_refcount(bs, cluster_index) == 0)
+                /* do nothing -- reserved for free counting */;
+            else
+                h = cluster_index;
+        }
+    }
+
+    if (high)
+        *high = (h+1);
+}
+
 static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
 {
     BDRVQcowState *s = bs->opaque;
@@ -2246,6 +2277,10 @@ retry:
             size,
             (s->free_cluster_index - nb_clusters) << s->cluster_bits);
 #endif
+
+    if (s->highest_alloc < s->free_cluster_index)
+        s->highest_alloc = s->free_cluster_index;
+
     return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
 }