[Qemu-devel] [PATCH 18/23] blockdev: Fix blockdev-add not to create IDE drive (0, 0)

[Markus Armbruster <armbru@redhat.com>]

blockdev_init() always creates a DriveInfo, but only drive_new() fills
it in.  qmp_blockdev_add() leaves it blank.  This results in a drive
with type = IF_IDE, bus = 0, unit = 0.  Screwed up in commit ee13ed1c.

Board initialization code looking for IDE drive (0,0) can pick up one
of these bogus drives.  Not sure whether getting the QMP command
executed early enough is likely in practice, though.

Fix by creating DriveInfo in drive_new().  Block backends created by
blockdev-add don't get one.

A few places assume a block backend always has a DriveInfo.  Fix them
up.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 blockdev.c          | 10 ++--------
 hw/block/block.c    | 16 ++++++++++------
 hw/ide/qdev.c       |  2 +-
 hw/scsi/scsi-disk.c |  2 +-
 4 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 4488dfd..12906a6 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -285,7 +285,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     int on_read_error, on_write_error;
     BlockBackend *blk;
     BlockDriverState *bs;
-    DriveInfo *dinfo;
     ThrottleConfig cfg;
     int snapshot = 0;
     bool copy_on_read;
@@ -457,9 +456,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         bdrv_set_io_limits(bs, &cfg);
     }
 
-    dinfo = g_malloc0(sizeof(*dinfo));
-    blk_set_legacy_dinfo(blk, dinfo);
-
     if (!file || !*file) {
         if (has_driver_specific_opts) {
             file = NULL;
@@ -902,21 +898,19 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     }
 
     /* Set legacy DriveInfo fields */
-    dinfo = blk_legacy_dinfo(blk);
+    dinfo = g_malloc0(sizeof(*dinfo));
     dinfo->enable_auto_del = true;
     dinfo->opts = all_opts;
-
     dinfo->cyls = cyls;
     dinfo->heads = heads;
     dinfo->secs = secs;
     dinfo->trans = translation;
-
     dinfo->type = type;
     dinfo->bus = bus_id;
     dinfo->unit = unit_id;
     dinfo->devaddr = devaddr;
-
     dinfo->serial = g_strdup(serial);
+    blk_set_legacy_dinfo(blk, dinfo);
 
     switch(type) {
     case IF_IDE:
diff --git a/hw/block/block.c b/hw/block/block.c
index 0666dd3..a625773 100644
--- a/hw/block/block.c
+++ b/hw/block/block.c
@@ -19,7 +19,9 @@ void blkconf_serial(BlockConf *conf, char **serial)
     if (!*serial) {
         /* try to fall back to value set with legacy -drive serial=... */
         dinfo = blk_legacy_dinfo(conf->blk);
-        *serial = g_strdup(dinfo->serial);
+        if (dinfo) {
+            *serial = g_strdup(dinfo->serial);
+        }
     }
 }
 
@@ -32,11 +34,13 @@ void blkconf_geometry(BlockConf *conf, int *ptrans,
     if (!conf->cyls && !conf->heads && !conf->secs) {
         /* try to fall back to value set with legacy -drive cyls=... */
         dinfo = blk_legacy_dinfo(conf->blk);
-        conf->cyls  = dinfo->cyls;
-        conf->heads = dinfo->heads;
-        conf->secs  = dinfo->secs;
-        if (ptrans) {
-            *ptrans = dinfo->trans;
+        if (dinfo) {
+            conf->cyls  = dinfo->cyls;
+            conf->heads = dinfo->heads;
+            conf->secs  = dinfo->secs;
+            if (ptrans) {
+                *ptrans = dinfo->trans;
+            }
         }
     }
     if (!conf->cyls && !conf->heads && !conf->secs) {
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index 4818334..a74c81e 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -206,7 +206,7 @@ static int ide_drive_initfn(IDEDevice *dev)
 {
     DriveInfo *dinfo = blk_legacy_dinfo(dev->conf.blk);
 
-    return ide_dev_initfn(dev, dinfo->media_cd ? IDE_CD : IDE_HD);
+    return ide_dev_initfn(dev, dinfo && dinfo->media_cd ? IDE_CD : IDE_HD);
 }
 
 #define DEFINE_IDE_DEV_PROPERTIES()                     \
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 768c1ad..e0c5ed3 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2331,7 +2331,7 @@ static void scsi_disk_realize(SCSIDevice *dev, Error **errp)
     }
 
     dinfo = blk_legacy_dinfo(dev->conf.blk);
-    if (dinfo->media_cd) {
+    if (dinfo && dinfo->media_cd) {
         scsi_cd_realize(dev, errp);
     } else {
         scsi_hd_realize(dev, errp);
-- 
1.9.3