[qemu-xen staging] xen-block: Use specific blockdev driver

[patchbot@xxxxxxx]

commit 136c34c9bc4179dc64b15b2bb5f0c54ca4ddf823
Author:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
AuthorDate: Fri Apr 30 17:34:32 2021 +0100
Commit:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
CommitDate: Mon Jul 5 10:45:21 2021 +0100

    xen-block: Use specific blockdev driver
    
    ... when a xen-block backend instance is created via xenstore.
    
    Following 8d17adf34f50 ("block: remove support for using "file" driver
    with block/char devices"), using the "file" blockdev driver for
    everything doesn't work anymore, we need to use the "host_device"
    driver when the disk image is a block device and "file" driver when it
    is a regular file.
    
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Acked-by: Paul Durrant <paul@xxxxxxx>
    Message-Id: <20210430163432.468894-1-anthony.perard@xxxxxxxxxx>
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    (cherry picked from commit 1898293990702c5601e225dac9afd2402fc46e2d)
---
 hw/block/xen-block.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 83754a4344..674953f1ad 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -728,6 +728,8 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
     XenBlockDrive *drive = NULL;
     QDict *file_layer;
     QDict *driver_layer;
+    struct stat st;
+    int rc;
 
     if (params) {
         char **v = g_strsplit(params, ":", 2);
@@ -761,7 +763,17 @@ static XenBlockDrive *xen_block_drive_create(const char 
*id,
     file_layer = qdict_new();
     driver_layer = qdict_new();
 
-    qdict_put_str(file_layer, "driver", "file");
+    rc = stat(filename, &st);
+    if (rc) {
+        error_setg_errno(errp, errno, "Could not stat file '%s'", filename);
+        goto done;
+    }
+    if (S_ISBLK(st.st_mode)) {
+        qdict_put_str(file_layer, "driver", "host_device");
+    } else {
+        qdict_put_str(file_layer, "driver", "file");
+    }
+
     qdict_put_str(file_layer, "filename", filename);
     g_free(filename);
 
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging