[PATCH 2/2] block: trickle down the fallback image creation function use to the block drivers

[Maxim Levitsky <mlevitsk@redhat.com>]

Instead of checking the .bdrv_co_create_opts to see if we need the failback,
just implement the .bdrv_co_create_opts in the drivers that need it.

This way we don't break various places that need to know if the underlying
protocol/format really supports image creation, and this way we still
allow some drivers to not support image creation.

Fixes: fd17146cd93d1704cd96d7c2757b325fc7aac6fd
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1816007

Note that technically this driver reverts the image creation failback
for the vxhs driver since I don't have a means to test it,
and IMHO it is better to leave it not supported as it was prior to
generic image creation patches.

Also drop iscsi_create_opts which was left accidently

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 block.c               | 35 ++++++++++++++++++++---------------
 block/file-posix.c    |  7 ++++++-
 block/iscsi.c         | 16 ++++------------
 block/nbd.c           |  6 ++++++
 block/nvme.c          |  3 +++
 include/block/block.h |  7 +++++++
 6 files changed, 46 insertions(+), 28 deletions(-)

diff --git a/block.c b/block.c
index ff23e20443..72fdf56af7 100644
--- a/block.c
+++ b/block.c
@@ -598,8 +598,15 @@ static int create_file_fallback_zero_first_sector(BlockBackend *blk,
     return 0;
 }
 
-static int bdrv_create_file_fallback(const char *filename, BlockDriver *drv,
-                                     QemuOpts *opts, Error **errp)
+/**
+ * Simple implementation of bdrv_co_create_opts for protocol drivers
+ * which only support creation via opening a file
+ * (usually existing raw storage device)
+ */
+int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv,
+                                           const char *filename,
+                                           QemuOpts *opts,
+                                           Error **errp)
 {
     BlockBackend *blk;
     QDict *options;
@@ -663,11 +670,7 @@ int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
         return -ENOENT;
     }
 
-    if (drv->bdrv_co_create_opts) {
-        return bdrv_create(drv, filename, opts, errp);
-    } else {
-        return bdrv_create_file_fallback(filename, drv, opts, errp);
-    }
+    return bdrv_create(drv, filename, opts, errp);
 }
 
 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp)
@@ -1592,9 +1595,9 @@ QemuOptsList bdrv_runtime_opts = {
     },
 };
 
-static QemuOptsList fallback_create_opts = {
-    .name = "fallback-create-opts",
-    .head = QTAILQ_HEAD_INITIALIZER(fallback_create_opts.head),
+QemuOptsList bdrv_create_opts_simple = {
+    .name = "simple-create-opts",
+    .head = QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple.head),
     .desc = {
         {
             .name = BLOCK_OPT_SIZE,
@@ -5963,13 +5966,15 @@ void bdrv_img_create(const char *filename, const char *fmt,
         return;
     }
 
+    if (!proto_drv->create_opts) {
+        error_setg(errp, "Protocol driver '%s' does not support image creation",
+                   proto_drv->format_name);
+        return;
+    }
+
     /* Create parameter list */
     create_opts = qemu_opts_append(create_opts, drv->create_opts);
-    if (proto_drv->create_opts) {
-        create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
-    } else {
-        create_opts = qemu_opts_append(create_opts, &fallback_create_opts);
-    }
+    create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
 
     opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
 
diff --git a/block/file-posix.c b/block/file-posix.c
index 65bc980bc4..7e19bbff5f 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -3513,6 +3513,8 @@ static BlockDriver bdrv_host_device = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
+    .bdrv_co_create_opts = bdrv_co_create_opts_simple,
+    .create_opts         = &bdrv_create_opts_simple,
     .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
     .bdrv_co_pwrite_zeroes = hdev_co_pwrite_zeroes,
@@ -3639,10 +3641,11 @@ static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
+    .bdrv_co_create_opts = bdrv_co_create_opts_simple,
+    .create_opts         = &bdrv_create_opts_simple,
     .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
 
-
     .bdrv_co_preadv         = raw_co_preadv,
     .bdrv_co_pwritev        = raw_co_pwritev,
     .bdrv_co_flush_to_disk  = raw_co_flush_to_disk,
@@ -3771,6 +3774,8 @@ static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
+    .bdrv_co_create_opts = bdrv_co_create_opts_simple,
+    .create_opts         = &bdrv_create_opts_simple,
     .mutable_opts       = mutable_opts,
 
     .bdrv_co_preadv         = raw_co_preadv,
diff --git a/block/iscsi.c b/block/iscsi.c
index 682abd8e09..14680a436a 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2399,18 +2399,6 @@ out_unlock:
     return r;
 }
 
-static QemuOptsList iscsi_create_opts = {
-    .name = "iscsi-create-opts",
-    .head = QTAILQ_HEAD_INITIALIZER(iscsi_create_opts.head),
-    .desc = {
-        {
-            .name = BLOCK_OPT_SIZE,
-            .type = QEMU_OPT_SIZE,
-            .help = "Virtual disk size"
-        },
-        { /* end of list */ }
-    }
-};
 
 static const char *const iscsi_strong_runtime_opts[] = {
     "transport",
@@ -2434,6 +2422,8 @@ static BlockDriver bdrv_iscsi = {
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
+    .bdrv_co_create_opts    = bdrv_co_create_opts_simple,
+    .create_opts            = &bdrv_create_opts_simple,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache = iscsi_co_invalidate_cache,
@@ -2471,6 +2461,8 @@ static BlockDriver bdrv_iser = {
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
+    .bdrv_co_create_opts    = bdrv_co_create_opts_simple,
+    .create_opts            = &bdrv_create_opts_simple,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache  = iscsi_co_invalidate_cache,
diff --git a/block/nbd.c b/block/nbd.c
index 976be76647..2160859f64 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -2038,6 +2038,8 @@ static BlockDriver bdrv_nbd = {
     .protocol_name              = "nbd",
     .instance_size              = sizeof(BDRVNBDState),
     .bdrv_parse_filename        = nbd_parse_filename,
+    .bdrv_co_create_opts        = bdrv_co_create_opts_simple,
+    .create_opts                = &bdrv_create_opts_simple,
     .bdrv_file_open             = nbd_open,
     .bdrv_reopen_prepare        = nbd_client_reopen_prepare,
     .bdrv_co_preadv             = nbd_client_co_preadv,
@@ -2063,6 +2065,8 @@ static BlockDriver bdrv_nbd_tcp = {
     .protocol_name              = "nbd+tcp",
     .instance_size              = sizeof(BDRVNBDState),
     .bdrv_parse_filename        = nbd_parse_filename,
+    .bdrv_co_create_opts        = bdrv_co_create_opts_simple,
+    .create_opts                = &bdrv_create_opts_simple,
     .bdrv_file_open             = nbd_open,
     .bdrv_reopen_prepare        = nbd_client_reopen_prepare,
     .bdrv_co_preadv             = nbd_client_co_preadv,
@@ -2088,6 +2092,8 @@ static BlockDriver bdrv_nbd_unix = {
     .protocol_name              = "nbd+unix",
     .instance_size              = sizeof(BDRVNBDState),
     .bdrv_parse_filename        = nbd_parse_filename,
+    .bdrv_co_create_opts        = bdrv_co_create_opts_simple,
+    .create_opts                = &bdrv_create_opts_simple,
     .bdrv_file_open             = nbd_open,
     .bdrv_reopen_prepare        = nbd_client_reopen_prepare,
     .bdrv_co_preadv             = nbd_client_co_preadv,
diff --git a/block/nvme.c b/block/nvme.c
index d41c4bda6e..7b7c0cc5d6 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -1333,6 +1333,9 @@ static BlockDriver bdrv_nvme = {
     .protocol_name            = "nvme",
     .instance_size            = sizeof(BDRVNVMeState),
 
+    .bdrv_co_create_opts      = bdrv_co_create_opts_simple,
+    .create_opts              = &bdrv_create_opts_simple,
+
     .bdrv_parse_filename      = nvme_parse_filename,
     .bdrv_file_open           = nvme_file_open,
     .bdrv_close               = nvme_close,
diff --git a/include/block/block.h b/include/block/block.h
index e569a4d747..7d36ec5433 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -283,6 +283,13 @@ BlockDriver *bdrv_find_format(const char *format_name);
 int bdrv_create(BlockDriver *drv, const char* filename,
                 QemuOpts *opts, Error **errp);
 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
+
+int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv,
+                                           const char *filename,
+                                           QemuOpts *opts,
+                                           Error **errp);
+extern QemuOptsList bdrv_create_opts_simple;
+
 BlockDriverState *bdrv_new(void);
 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
                  Error **errp);
-- 
2.17.2