block: Add strong_runtime_opts to BlockDriver

This new field can be set by block drivers to list the runtime options
they accept that may influence the contents of the respective BDS. As of
a follow-up patch, this list will be used by the common
bdrv_refresh_filename() implementation to decide which options to put
into BDS.full_open_options (and consequently whether a JSON filename has
to be created), thus freeing the drivers of having to implement that
logic themselves.

Additionally, this patch adds the field to all of the block drivers that
need it and sets it accordingly.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190201192935.18394-22-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/block/blkdebug.c b/block/blkdebug.c
index 0759452..71b4275 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -888,6 +888,20 @@
     return 0;
 }
 
+static const char *const blkdebug_strong_runtime_opts[] = {
+    "config",
+    "inject-error.",
+    "set-state.",
+    "align",
+    "max-transfer",
+    "opt-write-zero",
+    "max-write-zero",
+    "opt-discard",
+    "max-discard",
+
+    NULL
+};
+
 static BlockDriver bdrv_blkdebug = {
     .format_name            = "blkdebug",
     .protocol_name          = "blkdebug",
@@ -917,6 +931,8 @@
                                 = blkdebug_debug_remove_breakpoint,
     .bdrv_debug_resume          = blkdebug_debug_resume,
     .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,
+
+    .strong_runtime_opts        = blkdebug_strong_runtime_opts,
 };
 
 static void bdrv_blkdebug_init(void)
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 36e3d0f..5da5df1 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -517,6 +517,13 @@
                                  LOG_DISCARD_FLAG, false);
 }
 
+static const char *const blk_log_writes_strong_runtime_opts[] = {
+    "log-append",
+    "log-sector-size",
+
+    NULL
+};
+
 static BlockDriver bdrv_blk_log_writes = {
     .format_name            = "blklogwrites",
     .instance_size          = sizeof(BDRVBlkLogWritesState),
@@ -536,6 +543,7 @@
     .bdrv_co_block_status   = bdrv_co_block_status_from_file,
 
     .is_filter              = true,
+    .strong_runtime_opts    = blk_log_writes_strong_runtime_opts,
 };
 
 static void bdrv_blk_log_writes_init(void)
diff --git a/block/crypto.c b/block/crypto.c
index d5b1da6..fd8c7cf 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -619,6 +619,12 @@
     return spec_info;
 }
 
+static const char *const block_crypto_strong_runtime_opts[] = {
+    BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
+
+    NULL
+};
+
 BlockDriver bdrv_crypto_luks = {
     .format_name        = "luks",
     .instance_size      = sizeof(BlockCrypto),
@@ -640,6 +646,8 @@
     .bdrv_getlength     = block_crypto_getlength,
     .bdrv_get_info      = block_crypto_get_info_luks,
     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
+
+    .strong_runtime_opts = block_crypto_strong_runtime_opts,
 };
 
 static void block_crypto_init(void)
diff --git a/block/curl.c b/block/curl.c
index b7ac265..1c9e4f6 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -947,6 +947,19 @@
     return s->len;
 }
 
+static const char *const curl_strong_runtime_opts[] = {
+    CURL_BLOCK_OPT_URL,
+    CURL_BLOCK_OPT_SSLVERIFY,
+    CURL_BLOCK_OPT_COOKIE,
+    CURL_BLOCK_OPT_COOKIE_SECRET,
+    CURL_BLOCK_OPT_USERNAME,
+    CURL_BLOCK_OPT_PASSWORD_SECRET,
+    CURL_BLOCK_OPT_PROXY_USERNAME,
+    CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET,
+
+    NULL
+};
+
 static BlockDriver bdrv_http = {
     .format_name                = "http",
     .protocol_name              = "http",
@@ -961,6 +974,8 @@
 
     .bdrv_detach_aio_context    = curl_detach_aio_context,
     .bdrv_attach_aio_context    = curl_attach_aio_context,
+
+    .strong_runtime_opts        = curl_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_https = {
@@ -977,6 +992,8 @@
 
     .bdrv_detach_aio_context    = curl_detach_aio_context,
     .bdrv_attach_aio_context    = curl_attach_aio_context,
+
+    .strong_runtime_opts        = curl_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_ftp = {
@@ -993,6 +1010,8 @@
 
     .bdrv_detach_aio_context    = curl_detach_aio_context,
     .bdrv_attach_aio_context    = curl_attach_aio_context,
+
+    .strong_runtime_opts        = curl_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_ftps = {
@@ -1009,6 +1028,8 @@
 
     .bdrv_detach_aio_context    = curl_detach_aio_context,
     .bdrv_attach_aio_context    = curl_attach_aio_context,
+
+    .strong_runtime_opts        = curl_strong_runtime_opts,
 };
 
 static void curl_block_init(void)
diff --git a/block/gluster.c b/block/gluster.c
index 7289106..af64330 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -1495,6 +1495,21 @@
 }
 
 
+static const char *const gluster_strong_open_opts[] = {
+    GLUSTER_OPT_VOLUME,
+    GLUSTER_OPT_PATH,
+    GLUSTER_OPT_TYPE,
+    GLUSTER_OPT_SERVER_PATTERN,
+    GLUSTER_OPT_HOST,
+    GLUSTER_OPT_PORT,
+    GLUSTER_OPT_TO,
+    GLUSTER_OPT_IPV4,
+    GLUSTER_OPT_IPV6,
+    GLUSTER_OPT_SOCKET,
+
+    NULL
+};
+
 static BlockDriver bdrv_gluster = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster",
@@ -1522,6 +1537,7 @@
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .create_opts                  = &qemu_gluster_create_opts,
+    .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static BlockDriver bdrv_gluster_tcp = {
@@ -1551,6 +1567,7 @@
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .create_opts                  = &qemu_gluster_create_opts,
+    .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static BlockDriver bdrv_gluster_unix = {
@@ -1580,6 +1597,7 @@
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .create_opts                  = &qemu_gluster_create_opts,
+    .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 /* rdma is deprecated (actually never supported for volfile fetch).
@@ -1615,6 +1633,7 @@
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .create_opts                  = &qemu_gluster_create_opts,
+    .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static void bdrv_gluster_init(void)
diff --git a/block/iscsi.c b/block/iscsi.c
index ff47320..a0c0084 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2448,6 +2448,20 @@
     }
 };
 
+static const char *const iscsi_strong_runtime_opts[] = {
+    "transport",
+    "portal",
+    "target",
+    "user",
+    "password",
+    "password-secret",
+    "lun",
+    "initiator-name",
+    "header-digest",
+
+    NULL
+};
+
 static BlockDriver bdrv_iscsi = {
     .format_name     = "iscsi",
     .protocol_name   = "iscsi",
@@ -2482,6 +2496,8 @@
 
     .bdrv_detach_aio_context = iscsi_detach_aio_context,
     .bdrv_attach_aio_context = iscsi_attach_aio_context,
+
+    .strong_runtime_opts = iscsi_strong_runtime_opts,
 };
 
 #if LIBISCSI_API_VERSION >= (20160603)
@@ -2519,6 +2535,8 @@
 
     .bdrv_detach_aio_context = iscsi_detach_aio_context,
     .bdrv_attach_aio_context = iscsi_attach_aio_context,
+
+    .strong_runtime_opts = iscsi_strong_runtime_opts,
 };
 #endif
 
diff --git a/block/nbd.c b/block/nbd.c
index 83e6e9e..318a587 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -538,6 +538,17 @@
     return NULL;
 }
 
+static const char *const nbd_strong_runtime_opts[] = {
+    "path",
+    "host",
+    "port",
+    "export",
+    "tls-creds",
+    "server.",
+
+    NULL
+};
+
 static BlockDriver bdrv_nbd = {
     .format_name                = "nbd",
     .protocol_name              = "nbd",
@@ -557,6 +568,7 @@
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
     .bdrv_dirname               = nbd_dirname,
+    .strong_runtime_opts        = nbd_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_nbd_tcp = {
@@ -578,6 +590,7 @@
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
     .bdrv_dirname               = nbd_dirname,
+    .strong_runtime_opts        = nbd_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_nbd_unix = {
@@ -599,6 +612,7 @@
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
     .bdrv_dirname               = nbd_dirname,
+    .strong_runtime_opts        = nbd_strong_runtime_opts,
 };
 
 static void bdrv_nbd_init(void)
diff --git a/block/nfs.c b/block/nfs.c
index 19ee07c..6985a44 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -878,6 +878,15 @@
 }
 #endif
 
+static const char *nfs_strong_runtime_opts[] = {
+    "path",
+    "user",
+    "group",
+    "server.",
+
+    NULL
+};
+
 static BlockDriver bdrv_nfs = {
     .format_name                    = "nfs",
     .protocol_name                  = "nfs",
@@ -905,6 +914,8 @@
     .bdrv_refresh_filename          = nfs_refresh_filename,
     .bdrv_dirname                   = nfs_dirname,
 
+    .strong_runtime_opts            = nfs_strong_runtime_opts,
+
 #ifdef LIBNFS_FEATURE_PAGECACHE
     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 #endif
diff --git a/block/null.c b/block/null.c
index d442d3e..858892f 100644
--- a/block/null.c
+++ b/block/null.c
@@ -252,6 +252,13 @@
     bs->full_open_options = qobject_ref(opts);
 }
 
+static const char *const null_strong_runtime_opts[] = {
+    BLOCK_OPT_SIZE,
+    NULL_OPT_ZEROES,
+
+    NULL
+};
+
 static BlockDriver bdrv_null_co = {
     .format_name            = "null-co",
     .protocol_name          = "null-co",
@@ -269,6 +276,7 @@
     .bdrv_co_block_status   = null_co_block_status,
 
     .bdrv_refresh_filename  = null_refresh_filename,
+    .strong_runtime_opts    = null_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_null_aio = {
@@ -288,6 +296,7 @@
     .bdrv_co_block_status   = null_co_block_status,
 
     .bdrv_refresh_filename  = null_refresh_filename,
+    .strong_runtime_opts    = null_strong_runtime_opts,
 };
 
 static void bdrv_null_init(void)
diff --git a/block/nvme.c b/block/nvme.c
index 6c2ce7d..bf656b2 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -1136,6 +1136,13 @@
     qemu_vfio_dma_unmap(s->vfio, host);
 }
 
+static const char *const nvme_strong_runtime_opts[] = {
+    NVME_BLOCK_OPT_DEVICE,
+    NVME_BLOCK_OPT_NAMESPACE,
+
+    NULL
+};
+
 static BlockDriver bdrv_nvme = {
     .format_name              = "nvme",
     .protocol_name            = "nvme",
@@ -1153,6 +1160,7 @@
 
     .bdrv_refresh_filename    = nvme_refresh_filename,
     .bdrv_refresh_limits      = nvme_refresh_limits,
+    .strong_runtime_opts      = nvme_strong_runtime_opts,
 
     .bdrv_detach_aio_context  = nvme_detach_aio_context,
     .bdrv_attach_aio_context  = nvme_attach_aio_context,
diff --git a/block/qcow.c b/block/qcow.c
index d47515d..25d2025 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -1186,6 +1186,12 @@
     }
 };
 
+static const char *const qcow_strong_runtime_opts[] = {
+    "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
+
+    NULL
+};
+
 static BlockDriver bdrv_qcow = {
     .format_name	= "qcow",
     .instance_size	= sizeof(BDRVQcowState),
@@ -1209,6 +1215,7 @@
     .bdrv_get_info          = qcow_get_info,
 
     .create_opts            = &qcow_create_opts,
+    .strong_runtime_opts    = qcow_strong_runtime_opts,
 };
 
 static void bdrv_qcow_init(void)
diff --git a/block/qcow2.c b/block/qcow2.c
index 3826ce7..92242fb 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4936,6 +4936,12 @@
     }
 };
 
+static const char *const qcow2_strong_runtime_opts[] = {
+    "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
+
+    NULL
+};
+
 BlockDriver bdrv_qcow2 = {
     .format_name        = "qcow2",
     .instance_size      = sizeof(BDRVQcow2State),
@@ -4984,6 +4990,7 @@
     .bdrv_inactivate            = qcow2_inactivate,
 
     .create_opts         = &qcow2_create_opts,
+    .strong_runtime_opts = qcow2_strong_runtime_opts,
     .bdrv_co_check       = qcow2_co_check,
     .bdrv_amend_options  = qcow2_amend_options,
 
diff --git a/block/quorum.c b/block/quorum.c
index a890f21..1af6458 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1104,6 +1104,15 @@
     return NULL;
 }
 
+static const char *const quorum_strong_runtime_opts[] = {
+    QUORUM_OPT_VOTE_THRESHOLD,
+    QUORUM_OPT_BLKVERIFY,
+    QUORUM_OPT_REWRITE,
+    QUORUM_OPT_READ_PATTERN,
+
+    NULL
+};
+
 static BlockDriver bdrv_quorum = {
     .format_name                        = "quorum",
 
@@ -1128,6 +1137,8 @@
 
     .is_filter                          = true,
     .bdrv_recurse_is_first_non_filter   = quorum_recurse_is_first_non_filter,
+
+    .strong_runtime_opts                = quorum_strong_runtime_opts,
 };
 
 static void bdrv_quorum_init(void)
diff --git a/block/raw-format.c b/block/raw-format.c
index d07bcda..e3e5ba2 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -532,6 +532,13 @@
                                  read_flags, write_flags);
 }
 
+static const char *const raw_strong_runtime_opts[] = {
+    "offset",
+    "size",
+
+    NULL
+};
+
 BlockDriver bdrv_raw = {
     .format_name          = "raw",
     .instance_size        = sizeof(BDRVRawState),
@@ -561,7 +568,8 @@
     .bdrv_lock_medium     = &raw_lock_medium,
     .bdrv_co_ioctl        = &raw_co_ioctl,
     .create_opts          = &raw_create_opts,
-    .bdrv_has_zero_init   = &raw_has_zero_init
+    .bdrv_has_zero_init   = &raw_has_zero_init,
+    .strong_runtime_opts  = raw_strong_runtime_opts,
 };
 
 static void bdrv_raw_init(void)
diff --git a/block/rbd.c b/block/rbd.c
index 8a1a9f4..0c549c9 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -1228,6 +1228,18 @@
     }
 };
 
+static const char *const qemu_rbd_strong_runtime_opts[] = {
+    "pool",
+    "image",
+    "conf",
+    "snapshot",
+    "user",
+    "server.",
+    "password-secret",
+
+    NULL
+};
+
 static BlockDriver bdrv_rbd = {
     .format_name            = "rbd",
     .instance_size          = sizeof(BDRVRBDState),
@@ -1265,6 +1277,8 @@
 #ifdef LIBRBD_SUPPORTS_INVALIDATE
     .bdrv_co_invalidate_cache = qemu_rbd_co_invalidate_cache,
 #endif
+
+    .strong_runtime_opts    = qemu_rbd_strong_runtime_opts,
 };
 
 static void bdrv_rbd_init(void)
diff --git a/block/replication.c b/block/replication.c
index 9b33200..4c80b54 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -676,6 +676,13 @@
     aio_context_release(aio_context);
 }
 
+static const char *const replication_strong_runtime_opts[] = {
+    REPLICATION_MODE,
+    REPLICATION_TOP_ID,
+
+    NULL
+};
+
 BlockDriver bdrv_replication = {
     .format_name                = "replication",
     .instance_size              = sizeof(BDRVReplicationState),
@@ -692,6 +699,7 @@
     .bdrv_recurse_is_first_non_filter = replication_recurse_is_first_non_filter,
 
     .has_variable_length        = true,
+    .strong_runtime_opts        = replication_strong_runtime_opts,
 };
 
 static void bdrv_replication_init(void)
diff --git a/block/sheepdog.c b/block/sheepdog.c
index b916ba0..cbdfe9a 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -3203,6 +3203,15 @@
     }
 };
 
+static const char *const sd_strong_runtime_opts[] = {
+    "vdi",
+    "snap-id",
+    "tag",
+    "server.",
+
+    NULL
+};
+
 static BlockDriver bdrv_sheepdog = {
     .format_name                  = "sheepdog",
     .protocol_name                = "sheepdog",
@@ -3238,6 +3247,7 @@
     .bdrv_attach_aio_context      = sd_attach_aio_context,
 
     .create_opts                  = &sd_create_opts,
+    .strong_runtime_opts          = sd_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_sheepdog_tcp = {
@@ -3275,6 +3285,7 @@
     .bdrv_attach_aio_context      = sd_attach_aio_context,
 
     .create_opts                  = &sd_create_opts,
+    .strong_runtime_opts          = sd_strong_runtime_opts,
 };
 
 static BlockDriver bdrv_sheepdog_unix = {
@@ -3312,6 +3323,7 @@
     .bdrv_attach_aio_context      = sd_attach_aio_context,
 
     .create_opts                  = &sd_create_opts,
+    .strong_runtime_opts          = sd_strong_runtime_opts,
 };
 
 static void bdrv_sheepdog_init(void)
diff --git a/block/ssh.c b/block/ssh.c
index bbc513e..190ef95 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -1254,6 +1254,17 @@
     return ssh_grow_file(s, offset, errp);
 }
 
+static const char *const ssh_strong_runtime_opts[] = {
+    "host",
+    "port",
+    "path",
+    "user",
+    "host_key_check",
+    "server.",
+
+    NULL
+};
+
 static BlockDriver bdrv_ssh = {
     .format_name                  = "ssh",
     .protocol_name                = "ssh",
@@ -1270,6 +1281,7 @@
     .bdrv_co_truncate             = ssh_co_truncate,
     .bdrv_co_flush_to_disk        = ssh_co_flush,
     .create_opts                  = &ssh_create_opts,
+    .strong_runtime_opts          = ssh_strong_runtime_opts,
 };
 
 static void bdrv_ssh_init(void)
diff --git a/block/throttle.c b/block/throttle.c
index 636c976..f64dcc2 100644
--- a/block/throttle.c
+++ b/block/throttle.c
@@ -227,6 +227,12 @@
     atomic_dec(&tgm->io_limits_disabled);
 }
 
+static const char *const throttle_strong_runtime_opts[] = {
+    QEMU_OPT_THROTTLE_GROUP_NAME,
+
+    NULL
+};
+
 static BlockDriver bdrv_throttle = {
     .format_name                        =   "throttle",
     .instance_size                      =   sizeof(ThrottleGroupMember),
@@ -259,6 +265,7 @@
     .bdrv_co_drain_end                  =   throttle_co_drain_end,
 
     .is_filter                          =   true,
+    .strong_runtime_opts                =   throttle_strong_runtime_opts,
 };
 
 static void bdrv_throttle_init(void)
diff --git a/block/vpc.c b/block/vpc.c
index 52ab717..a902a4c 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -1218,6 +1218,12 @@
     }
 };
 
+static const char *const vpc_strong_runtime_opts[] = {
+    VPC_OPT_SIZE_CALC,
+
+    NULL
+};
+
 static BlockDriver bdrv_vpc = {
     .format_name    = "vpc",
     .instance_size  = sizeof(BDRVVPCState),
@@ -1238,6 +1244,7 @@
 
     .create_opts            = &vpc_create_opts,
     .bdrv_has_zero_init     = vpc_has_zero_init,
+    .strong_runtime_opts    = vpc_strong_runtime_opts,
 };
 
 static void bdrv_vpc_init(void)
diff --git a/block/vvfat.c b/block/vvfat.c
index b7b61ea..5f66787 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3253,6 +3253,16 @@
     }
 }
 
+static const char *const vvfat_strong_runtime_opts[] = {
+    "dir",
+    "fat-type",
+    "floppy",
+    "label",
+    "rw",
+
+    NULL
+};
+
 static BlockDriver bdrv_vvfat = {
     .format_name            = "vvfat",
     .protocol_name          = "fat",
@@ -3267,6 +3277,8 @@
     .bdrv_co_preadv         = vvfat_co_preadv,
     .bdrv_co_pwritev        = vvfat_co_pwritev,
     .bdrv_co_block_status   = vvfat_co_block_status,
+
+    .strong_runtime_opts    = vvfat_strong_runtime_opts,
 };
 
 static void bdrv_vvfat_init(void)
diff --git a/block/vxhs.c b/block/vxhs.c
index 0cb0a00..2e18229 100644
--- a/block/vxhs.c
+++ b/block/vxhs.c
@@ -556,6 +556,16 @@
     return vdisk_size;
 }
 
+static const char *const vxhs_strong_runtime_opts[] = {
+    VXHS_OPT_VDISK_ID,
+    "tls-creds",
+    VXHS_OPT_HOST,
+    VXHS_OPT_PORT,
+    VXHS_OPT_SERVER".",
+
+    NULL
+};
+
 static BlockDriver bdrv_vxhs = {
     .format_name                  = "vxhs",
     .protocol_name                = "vxhs",
@@ -567,6 +577,7 @@
     .bdrv_getlength               = vxhs_getlength,
     .bdrv_aio_preadv              = vxhs_aio_preadv,
     .bdrv_aio_pwritev             = vxhs_aio_pwritev,
+    .strong_runtime_opts          = vxhs_strong_runtime_opts,
 };
 
 static void bdrv_vxhs_init(void)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index e4d4817..160e8ca 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -517,6 +517,13 @@
     void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size);
     void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host);
     QLIST_ENTRY(BlockDriver) list;
+
+    /* Pointer to a NULL-terminated array of names of strong options
+     * that can be specified for bdrv_open(). A strong option is one
+     * that changes the data of a BDS.
+     * If this pointer is NULL, the array is considered empty.
+     * "filename" and "driver" are always considered strong. */
+    const char *const *strong_runtime_opts;
 };
 
 typedef struct BlockLimits {