[Qemu-devel] [RFC PATCH v4 4/4] qcow2: Add full image preallocation option

[Hu Tao]

This adds a preallocation=full mode to qcow2 image creation, which
creates a non-sparse image file.

Signed-off-by: Hu Tao <hu...@cn.fujitsu.com>
---
 block/qcow2.c | 48 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index f0a8d87..f601089 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1448,6 +1448,7 @@ static int qcow2_create2(const char *filename, int64_t 
total_size,
                          QEMUOptionParameter *options, int version,
                          Error **errp)
 {
+    QEMUOptionParameter *alloc_options = NULL;
     /* Calculate cluster_bits */
     int cluster_bits;
     cluster_bits = ffs(cluster_size) - 1;
@@ -1477,16 +1478,53 @@ static int qcow2_create2(const char *filename, int64_t 
total_size,
     Error *local_err = NULL;
     int ret;
 
+    if (prealloc == PREALLOC_MODE_FULL) {
+        int64_t meta_size = 0;
+        unsigned nrefe, nl2e;
+        BlockDriver *drv;
+
+        drv = bdrv_find_protocol(filename, true);
+        if (drv == NULL) {
+            error_setg(errp, "Could not find protocol for file '%s'", 
filename);
+            return -ENOENT;
+        }
+
+        alloc_options = append_option_parameters(alloc_options,
+                                                 drv->create_options);
+        alloc_options = append_option_parameters(alloc_options, options);
+
+        /* header: 1 cluster */
+        meta_size += cluster_size;
+        /* total size of refblocks */
+        nrefe = (total_size / cluster_size);
+        nrefe = align_offset(nrefe, cluster_size / sizeof(uint16_t));
+        meta_size += nrefe * sizeof(uint16_t);
+        /* total size of reftables */
+        meta_size += nrefe * sizeof(uint16_t) * sizeof(uint16_t) / 
cluster_size;
+        /* total size of L2 tables */
+        nl2e = total_size / cluster_size;
+        nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
+        meta_size += nl2e * sizeof(uint64_t);
+        /* total size of L1 tables */
+        meta_size += nl2e * sizeof(uint64_t) * sizeof(uint64_t) / cluster_size;
+
+        set_option_parameter_int(alloc_options, BLOCK_OPT_SIZE,
+                                 total_size + meta_size);
+        set_option_parameter(alloc_options, BLOCK_OPT_PREALLOC, "full");
+
+        options = alloc_options;
+    }
+
     ret = bdrv_create_file(filename, options, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
-        return ret;
+        goto out_options;
     }
 
     ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
-        return ret;
+        goto out_options;
     }
 
     /* Write the header */
@@ -1603,6 +1641,8 @@ static int qcow2_create2(const char *filename, int64_t 
total_size,
     ret = 0;
 out:
     bdrv_unref(bs);
+out_options:
+    free_option_parameters(alloc_options);
     return ret;
 }
 
@@ -1638,6 +1678,8 @@ static int qcow2_create(const char *filename, 
QEMUOptionParameter *options,
                 prealloc = PREALLOC_MODE_OFF;
             } else if (!strcmp(options->value.s, "metadata")) {
                 prealloc = PREALLOC_MODE_METADATA;
+            } else if (!strcmp(options->value.s, "full")) {
+                prealloc = PREALLOC_MODE_FULL;
             } else {
                 error_setg(errp, "Invalid preallocation mode: '%s'",
                            options->value.s);
@@ -2223,7 +2265,7 @@ static QEMUOptionParameter qcow2_create_options[] = {
     {
         .name = BLOCK_OPT_PREALLOC,
         .type = OPT_STRING,
-        .help = "Preallocation mode (allowed values: off, metadata)"
+        .help = "Preallocation mode (allowed values: off, metadata, full)"
     },
     {
         .name = BLOCK_OPT_LAZY_REFCOUNTS,
-- 
1.7.11.7