blockdev: Orphaned drive search

When users use command line options like -hda, -cdrom,
or even -drive if=ide, it is up to the board initialization
routines to pick up these drives and create backing
devices for them.

Some boards, like Q35, have not been doing this.
However, there is no warning explaining why certain
drive specifications are just silently ignored,
so this function adds a check to print some warnings
to assist users in debugging these sorts of issues
in the future.

This patch will not warn about drives added with if_none,
for which it is not possible to tell in advance if
the omission of a backing device is an issue.

A warning in these cases is considered appropriate.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1412187569-23452-2-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/blockdev.c b/blockdev.c
index dc94ad319ac39e0dff2fbf9fcf98ad7637598a6d..48da1a7e0f6ddd72993531233b704e38472a1acd 100644 (file)
--- a/blockdev.c
+++ b/blockdev.c
@@ -166,6 +166,27 @@ DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
     return NULL;
 }
 
+bool drive_check_orphaned(void)
+{
+    DriveInfo *dinfo;
+    bool rs = false;
+
+    QTAILQ_FOREACH(dinfo, &drives, next) {
+        /* If dinfo->bdrv->dev is NULL, it has no device attached. */
+        /* Unless this is a default drive, this may be an oversight. */
+        if (!dinfo->bdrv->dev && !dinfo->is_default &&
+            dinfo->type != IF_NONE) {
+            fprintf(stderr, "Warning: Orphaned drive without device: "
+                    "id=%s,file=%s,if=%s,bus=%d,unit=%d\n",
+                    dinfo->id, dinfo->bdrv->filename, if_name[dinfo->type],
+                    dinfo->bus, dinfo->unit);
+            rs = true;
+        }
+    }
+
+    return rs;
+}
+
 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
 {
     return drive_get(type,

diff --git a/include/sysemu/blockdev.h b/include/sysemu/blockdev.h
index abec3810493d32f77aaaced959ab30c553f03906..30402867b95959c8f5194382a45d54c8a259199f 100644 (file)
--- a/include/sysemu/blockdev.h
+++ b/include/sysemu/blockdev.h
@@ -38,6 +38,7 @@ struct DriveInfo {
     int unit;
     int auto_del;               /* see blockdev_mark_auto_del() */
     bool enable_auto_del;       /* Only for legacy drive_new() */
+    bool is_default;            /* Added by default_drive() ?  */
     int media_cd;
     int cyls, heads, secs, trans;
     QemuOpts *opts;
@@ -46,6 +47,7 @@ struct DriveInfo {
 };
 
 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
+bool drive_check_orphaned(void);
 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index);
 int drive_get_max_bus(BlockInterfaceType type);
 DriveInfo *drive_get_next(BlockInterfaceType type);

diff --git a/vl.c b/vl.c
index 9d2aaaf1dcf2281b34c973f4da172667dda9df96..4bc8f97c25a2e300bf856fec177e69fbcc51125b 100644 (file)
--- a/vl.c
+++ b/vl.c
@@ -1169,6 +1169,7 @@ static void default_drive(int enable, int snapshot, BlockInterfaceType type,
                           int index, const char *optstr)
 {
     QemuOpts *opts;
+    DriveInfo *dinfo;
 
     if (!enable || drive_get_by_index(type, index)) {
         return;
@@ -1178,9 +1179,13 @@ static void default_drive(int enable, int snapshot, BlockInterfaceType type,
     if (snapshot) {
         drive_enable_snapshot(opts, NULL);
     }
-    if (!drive_new(opts, type)) {
+
+    dinfo = drive_new(opts, type);
+    if (!dinfo) {
         exit(1);
     }
+    dinfo->is_default = true;
+
 }
 
 void qemu_register_boot_set(QEMUBootSetHandler *func, void *opaque)
@@ -4457,6 +4462,9 @@ int main(int argc, char **argv, char **envp)
     if (qemu_opts_foreach(qemu_find_opts("device"), device_init_func, NULL, 1) != 0)
         exit(1);
 
+    /* Did we create any drives that we failed to create a device for? */
+    drive_check_orphaned();
+
     net_check_clients();
 
     ds = init_displaystate();