[PATCH v9 5/7] config: add check to block layer

[Sam Li]

Putting zoned/non-zoned BlockDrivers on top of each other is not
allowed.

Signed-off-by: Sam Li <faithilikerun@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block.c                          | 14 ++++++++++++++
 block/file-posix.c               | 14 ++++++++++++++
 block/raw-format.c               |  1 +
 include/block/block_int-common.h |  5 +++++
 4 files changed, 34 insertions(+)

diff --git a/block.c b/block.c
index bc85f46eed..dad2ed3959 100644
--- a/block.c
+++ b/block.c
@@ -7947,6 +7947,20 @@ void bdrv_add_child(BlockDriverState *parent_bs, 
BlockDriverState *child_bs,
         return;
     }
 
+    /*
+     * Non-zoned block drivers do not follow zoned storage constraints
+     * (i.e. sequential writes to zones). Refuse mixing zoned and non-zoned
+     * drivers in a graph.
+     */
+    if (!parent_bs->drv->supports_zoned_children &&
+        child_bs->bl.zoned == BLK_Z_HM) {
+        error_setg(errp, "Cannot add a %s child to a %s parent",
+                   child_bs->bl.zoned == BLK_Z_HM ? "zoned" : "non-zoned",
+                   parent_bs->drv->supports_zoned_children ?
+                   "support zoned children" : "not support zoned children");
+        return;
+    }
+
     if (!QLIST_EMPTY(&child_bs->parents)) {
         error_setg(errp, "The node %s already has a parent",
                    child_bs->node_name);
diff --git a/block/file-posix.c b/block/file-posix.c
index 4edfa25d04..354de22860 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -779,6 +779,20 @@ static int raw_open_common(BlockDriverState *bs, QDict 
*options,
             goto fail;
         }
     }
+#ifdef CONFIG_BLKZONED
+    /*
+     * The kernel page chache does not reliably work for writes to SWR zones
+     * of zoned block device because it can not guarantee the order of writes.
+     */
+    if (strcmp(bs->drv->format_name, "zoned_host_device") == 0) {
+        if (!(s->open_flags & O_DIRECT)) {
+            error_setg(errp, "driver=zoned_host_device was specified, but it "
+                             "requires cache.direct=on, which was not 
specified.");
+            ret = -EINVAL;
+            return ret; /* No host kernel page cache */
+        }
+    }
+#endif
 
     if (S_ISBLK(st.st_mode)) {
 #ifdef BLKDISCARDZEROES
diff --git a/block/raw-format.c b/block/raw-format.c
index 6b20bd22ef..9441536819 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -614,6 +614,7 @@ static void raw_child_perm(BlockDriverState *bs, BdrvChild 
*c,
 BlockDriver bdrv_raw = {
     .format_name          = "raw",
     .instance_size        = sizeof(BDRVRawState),
+    .supports_zoned_children = true,
     .bdrv_probe           = &raw_probe,
     .bdrv_reopen_prepare  = &raw_reopen_prepare,
     .bdrv_reopen_commit   = &raw_reopen_commit,
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 078ddd7e67..043aa161a0 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -127,6 +127,11 @@ struct BlockDriver {
      */
     bool is_format;
 
+    /*
+     * Set to true if the BlockDriver supports zoned children.
+     */
+    bool supports_zoned_children;
+
     /*
      * Drivers not implementing bdrv_parse_filename nor bdrv_open should have
      * this field set to true, except ones that are defined only by their
-- 
2.37.3