block/vhdx: Make vhdx_create() always set errp

This patch makes vhdx_create() always set errp in case of an error. It
also adds errp parameters to vhdx_create_bat() and
vhdx_create_new_region_table() so we can pass on the error object
generated by blk_truncate() as of a future commit.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20170328205129.15138-2-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

block/vhdx.c

@@ -1586,7 +1586,7 @@ static int vhdx_create_new_metadata(BlockBackend *blk,
 static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
                            uint64_t image_size, VHDXImageType type,
                            bool use_zero_blocks, uint64_t file_offset,
-                           uint32_t length)
+                           uint32_t length, Error **errp)
 {
     int ret = 0;
     uint64_t data_file_offset;
@@ -1609,14 +1609,19 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
          * is the furthest thing we have written yet */
         ret = blk_truncate(blk, data_file_offset);
         if (ret < 0) {
+            error_setg_errno(errp, -ret,
+                            "Failed to resize the underlying file");
             goto exit;
         }
     } else if (type == VHDX_TYPE_FIXED) {
         ret = blk_truncate(blk, data_file_offset + image_size);
         if (ret < 0) {
+            error_setg_errno(errp, -ret,
+                            "Failed to resize the underlying file");
             goto exit;
         }
     } else {
+        error_setg(errp, "Unsupported image type");
         ret = -ENOTSUP;
         goto exit;
     }
@@ -1627,6 +1632,7 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
         /* for a fixed file, the default BAT entry is not zero */
         s->bat = g_try_malloc0(length);
         if (length && s->bat == NULL) {
+            error_setg(errp, "Failed to allocate memory for the BAT");
             ret = -ENOMEM;
             goto exit;
         }
@@ -1646,6 +1652,7 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
         }
         ret = blk_pwrite(blk, file_offset, s->bat, length, 0);
         if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to write the BAT");
             goto exit;
         }
     }
@@ -1671,7 +1678,8 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
                                         uint32_t log_size,
                                         bool use_zero_blocks,
                                         VHDXImageType type,
-                                        uint64_t *metadata_offset)
+                                        uint64_t *metadata_offset,
+                                        Error **errp)
 {
     int ret = 0;
     uint32_t offset = 0;
@@ -1740,7 +1748,7 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
     /* The region table gives us the data we need to create the BAT,
      * so do that now */
     ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
-                          bat_file_offset, bat_length);
+                          bat_file_offset, bat_length, errp);
     if (ret < 0) {
         goto exit;
     }
@@ -1749,12 +1757,14 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
     ret = blk_pwrite(blk, VHDX_REGION_TABLE_OFFSET, buffer,
                      VHDX_HEADER_BLOCK_SIZE, 0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write first region table");
         goto exit;
     }
 
     ret = blk_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, buffer,
                      VHDX_HEADER_BLOCK_SIZE, 0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write second region table");
         goto exit;
     }
 
@@ -1825,6 +1835,7 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
         ret = -ENOTSUP;
         goto exit;
     } else {
+        error_setg(errp, "Invalid subformat '%s'", type);
         ret = -EINVAL;
         goto exit;
     }
@@ -1879,12 +1890,14 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature),
                      0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write file signature");
         goto delete_and_exit;
     }
     if (creator) {
         ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
                          creator, creator_items * sizeof(gunichar2), 0);
         if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to write creator field");
             goto delete_and_exit;
         }
     }
@@ -1893,13 +1906,14 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     /* Creates (B),(C) */
     ret = vhdx_create_new_headers(blk, image_size, log_size);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write image headers");
         goto delete_and_exit;
     }
 
     /* Creates (D),(E),(G) explicitly. (F) created as by-product */
     ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
                                        log_size, use_zero_blocks, image_type,
-                                       &metadata_offset);
+                                       &metadata_offset, errp);
     if (ret < 0) {
         goto delete_and_exit;
     }
@@ -1908,6 +1922,7 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
                                    metadata_offset, image_type);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to initialize metadata");
         goto delete_and_exit;
     }