[PULL,24/28] block: Add a 'mutable_opts' field to BlockDriver

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 438feba4e5..01e855a066 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -383,6 +383,14 @@  struct BlockDriver {
 
     /* List of options for creating images, terminated by name == NULL */
     QemuOptsList *create_opts;
+    /*
+     * If this driver supports reopening images this contains a
+     * NULL-terminated list of the runtime options that can be
+     * modified. If an option in this list is unspecified during
+     * reopen then it _must_ be reset to its default value or return
+     * an error.
+     */
+    const char *const *mutable_opts;
 
     /*
      * Returns 0 for completed check, -errno for internal errors.
diff --git a/block/file-posix.c b/block/file-posix.c
index d41059d139..e9fa6aac48 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -442,6 +442,8 @@  static QemuOptsList raw_runtime_opts = {
     },
 };
 
+static const char *const mutable_opts[] = { "x-check-cache-dropped", NULL };
+
 static int raw_open_common(BlockDriverState *bs, QDict *options,
                            int bdrv_flags, int open_flags,
                            bool device, Error **errp)
@@ -2870,6 +2872,7 @@  BlockDriver bdrv_file = {
     .bdrv_set_perm   = raw_set_perm,
     .bdrv_abort_perm_update = raw_abort_perm_update,
     .create_opts = &raw_create_opts,
+    .mutable_opts = mutable_opts,
 };
 
 /***********************************************/
@@ -3321,6 +3324,7 @@  static BlockDriver bdrv_host_device = {
     .bdrv_reopen_abort   = raw_reopen_abort,
     .bdrv_co_create_opts = hdev_co_create_opts,
     .create_opts         = &raw_create_opts,
+    .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
     .bdrv_co_pwrite_zeroes = hdev_co_pwrite_zeroes,
 
@@ -3447,6 +3451,7 @@  static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_abort   = raw_reopen_abort,
     .bdrv_co_create_opts = hdev_co_create_opts,
     .create_opts         = &raw_create_opts,
+    .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
 
 
@@ -3580,6 +3585,7 @@  static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_abort   = raw_reopen_abort,
     .bdrv_co_create_opts = hdev_co_create_opts,
     .create_opts        = &raw_create_opts,
+    .mutable_opts       = mutable_opts,
 
     .bdrv_co_preadv         = raw_co_preadv,
     .bdrv_co_pwritev        = raw_co_pwritev,
diff --git a/block/qcow2.c b/block/qcow2.c
index c4dd876fb4..0fc9b0561e 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -627,6 +627,30 @@  int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
     return 0;
 }
 
+static const char *const mutable_opts[] = {
+    QCOW2_OPT_LAZY_REFCOUNTS,
+    QCOW2_OPT_DISCARD_REQUEST,
+    QCOW2_OPT_DISCARD_SNAPSHOT,
+    QCOW2_OPT_DISCARD_OTHER,
+    QCOW2_OPT_OVERLAP,
+    QCOW2_OPT_OVERLAP_TEMPLATE,
+    QCOW2_OPT_OVERLAP_MAIN_HEADER,
+    QCOW2_OPT_OVERLAP_ACTIVE_L1,
+    QCOW2_OPT_OVERLAP_ACTIVE_L2,
+    QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
+    QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
+    QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
+    QCOW2_OPT_OVERLAP_INACTIVE_L1,
+    QCOW2_OPT_OVERLAP_INACTIVE_L2,
+    QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
+    QCOW2_OPT_CACHE_SIZE,
+    QCOW2_OPT_L2_CACHE_SIZE,
+    QCOW2_OPT_L2_CACHE_ENTRY_SIZE,
+    QCOW2_OPT_REFCOUNT_CACHE_SIZE,
+    QCOW2_OPT_CACHE_CLEAN_INTERVAL,
+    NULL
+};
+
 static QemuOptsList qcow2_runtime_opts = {
     .name = "qcow2",
     .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
@@ -5275,6 +5299,7 @@  BlockDriver bdrv_qcow2 = {
 
     .create_opts         = &qcow2_create_opts,
     .strong_runtime_opts = qcow2_strong_runtime_opts,
+    .mutable_opts        = mutable_opts,
     .bdrv_co_check       = qcow2_co_check,
     .bdrv_amend_options  = qcow2_amend_options,
 
diff --git a/block/raw-format.c b/block/raw-format.c
index e3e5ba2c8a..cec29986cc 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -37,6 +37,8 @@  typedef struct BDRVRawState {
     bool has_size;
 } BDRVRawState;
 
+static const char *const mutable_opts[] = { "offset", "size", NULL };
+
 static QemuOptsList raw_runtime_opts = {
     .name = "raw",
     .head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
@@ -570,6 +572,7 @@  BlockDriver bdrv_raw = {
     .create_opts          = &raw_create_opts,
     .bdrv_has_zero_init   = &raw_has_zero_init,
     .strong_runtime_opts  = raw_strong_runtime_opts,
+    .mutable_opts         = mutable_opts,
 };
 
 static void bdrv_raw_init(void)