[Qemu-devel] [PATCH v6 20/24] blockdev: Fix blockdev-add not to create DriveInfo

[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.  The QMP command has to execute really early to
be visible.  Not sure how likely that is in practice.

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

Breaks the test for "has been created by qmp_blockdev_add()" in
blockdev_mark_auto_del() and do_drive_del(), because it changes the
value of dinfo && !dinfo->enable_auto_del from true to false.  Simply
test !dinfo instead.

Leaves DriveInfo member enable_auto_del unused.  Drop it.

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

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/block-backend.c     |  2 +-
 blockdev.c                | 22 +++++++---------------
 hw/block/block.c          | 16 ++++++++++------
 hw/ide/qdev.c             |  2 +-
 hw/scsi/scsi-disk.c       |  2 +-
 include/sysemu/blockdev.h |  1 -
 6 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index a3e613b..ae30873 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -18,7 +18,7 @@ struct BlockBackend {
     char *name;
     int refcnt;
     BlockDriverState *bs;
-    DriveInfo *legacy_dinfo;
+    DriveInfo *legacy_dinfo;    /* null unless created by drive_new() */
     QTAILQ_ENTRY(BlockBackend) link; /* for blk_backends */
 };
 
diff --git a/blockdev.c b/blockdev.c
index cdefbb0..2a3d908 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -116,16 +116,14 @@ void blockdev_mark_auto_del(BlockBackend *blk)
     DriveInfo *dinfo = blk_legacy_dinfo(blk);
     BlockDriverState *bs = blk_bs(blk);
 
-    if (dinfo && !dinfo->enable_auto_del) {
+    if (!dinfo) {
         return;
     }
 
     if (bs->job) {
         block_job_cancel(bs->job);
     }
-    if (dinfo) {
-        dinfo->auto_del = 1;
-    }
+    dinfo->auto_del = 1;
 }
 
 void blockdev_auto_del(BlockBackend *blk)
@@ -346,7 +344,6 @@ 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;
@@ -518,9 +515,6 @@ 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;
@@ -990,9 +984,8 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
         assert(!local_err);
     }
 
-    /* Set legacy DriveInfo fields */
-    dinfo = blk_legacy_dinfo(blk);
-    dinfo->enable_auto_del = true;
+    /* Create legacy DriveInfo */
+    dinfo = g_malloc0(sizeof(*dinfo));
     dinfo->opts = all_opts;
 
     dinfo->cyls = cyls;
@@ -1004,9 +997,10 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_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:
     case IF_SCSI:
@@ -1810,7 +1804,6 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
     const char *id = qdict_get_str(qdict, "id");
     BlockBackend *blk;
     BlockDriverState *bs;
-    DriveInfo *dinfo;
     AioContext *aio_context;
     Error *local_err = NULL;
 
@@ -1821,8 +1814,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
     }
     bs = blk_bs(blk);
 
-    dinfo = blk_legacy_dinfo(blk);
-    if (dinfo && !dinfo->enable_auto_del) {
+    if (!blk_legacy_dinfo(blk)) {
         error_report("Deleting device added with blockdev-add"
                      " is not supported");
         return -1;
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 f3c9a6b..2278c7d 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2311,7 +2311,7 @@ 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);
diff --git a/include/sysemu/blockdev.h b/include/sysemu/blockdev.h
index 0c70c29..09d1e30 100644
--- a/include/sysemu/blockdev.h
+++ b/include/sysemu/blockdev.h
@@ -35,7 +35,6 @@ struct DriveInfo {
     int bus;
     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;
-- 
1.9.3