The monitor does hold references to some BlockBackends so it should have
a list of those BBs; blk_backends is a different list, as it contains
references to all BBs (after a follow-up patch, that is), and that
should not be changed because we do need such a list.
monitor_remove_blk() is idempotent so that we can call it in
blockdev_auto_del() without having to care whether it had been called in
do_drive_del() before. monitor_add_blk() is idempotent for symmetry
reasons (monitor_remove_blk() is, so it would be strange for
monitor_add_blk() not to be).
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block/block-backend.c | 34 +++++++++++++++++++++++++++++++++-
blockdev.c | 8 ++++++++
include/sysemu/block-backend.h | 2 ++
3 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index c89340e..e35d84f 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -29,6 +29,8 @@ struct BlockBackend {
BlockDriverState *bs;
DriveInfo *legacy_dinfo; /* null unless created by drive_new() */
QTAILQ_ENTRY(BlockBackend) link; /* for blk_backends */
+ QTAILQ_ENTRY(BlockBackend) monitor_link; /* for monitor_block_backends */
+ bool in_monitor_list;
void *dev; /* attached device model, if any */
/* TODO change to DeviceState when all users are qdevified */
@@ -70,6 +72,11 @@ static void drive_info_del(DriveInfo *dinfo);
static QTAILQ_HEAD(, BlockBackend) blk_backends =
QTAILQ_HEAD_INITIALIZER(blk_backends);
+/* All BlockBackends referenced by the monitor and which are iterated through
by
+ * blk_next() */
+static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
+ QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
+
/*
* Create a new BlockBackend with @name, with a reference count of one.
* @name must not be null or empty.
@@ -248,7 +255,8 @@ void blk_remove_all_bs(void)
*/
BlockBackend *blk_next(BlockBackend *blk)
{
- return blk ? QTAILQ_NEXT(blk, link) : QTAILQ_FIRST(&blk_backends);
+ return blk ? QTAILQ_NEXT(blk, monitor_link)
+ : QTAILQ_FIRST(&monitor_block_backends);
}
/*
@@ -267,6 +275,30 @@ BlockBackend *blk_next_inserted(BlockBackend *blk)
}
/*
+ * Add a BlockBackend into the list of backends referenced by the monitor.
+ * Strictly for use by blockdev.c.
+ */
+void monitor_add_blk(BlockBackend *blk)
+{
+ if (!blk->in_monitor_list) {
+ QTAILQ_INSERT_TAIL(&monitor_block_backends, blk, monitor_link);
+ blk->in_monitor_list = true;
+ }
+}
+
+/*
+ * Remove a BlockBackend from the list of backends referenced by the monitor.
+ * Strictly for use by blockdev.c.
+ */
+void monitor_remove_blk(BlockBackend *blk)
+{
+ if (blk->in_monitor_list) {
+ QTAILQ_REMOVE(&monitor_block_backends, blk, monitor_link);
+ blk->in_monitor_list = false;
+ }
+}
+
+/*
* Return @blk's name, a non-null string.
* Wart: the name is empty iff @blk has been hidden with
* blk_hide_on_behalf_of_hmp_drive_del().
diff --git a/blockdev.c b/blockdev.c
index 97e6897..f5dde19 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -146,6 +146,7 @@ void blockdev_auto_del(BlockBackend *blk)
DriveInfo *dinfo = blk_legacy_dinfo(blk);
if (dinfo && dinfo->auto_del) {
+ monitor_remove_blk(blk);
blk_unref(blk);
}
}
@@ -606,6 +607,8 @@ static BlockBackend *blockdev_init(const char *file, QDict
*bs_opts,
blk_set_on_error(blk, on_read_error, on_write_error);
+ monitor_add_blk(blk);
+
err_no_bs_opts:
qemu_opts_del(opts);
return blk;
@@ -2528,6 +2531,8 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
blk_remove_bs(blk);
}
+ monitor_remove_blk(blk);
+
/* if we have a device attached to this BlockDriverState
* then we need to make the drive anonymous until the device
* can be removed. If this is a drive with no device backing
@@ -3486,6 +3491,7 @@ void qmp_blockdev_add(BlockdevOptions *options, Error
**errp)
if (bs && bdrv_key_required(bs)) {
if (blk) {
+ monitor_remove_blk(blk);
blk_unref(blk);
} else {
QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
@@ -3515,6 +3521,7 @@ void qmp_x_blockdev_del(bool has_id, const char *id,
}
if (has_id) {
+ /* blk_by_name() never returns a BB that is not owned by the monitor */
blk = blk_by_name(id);
if (!blk) {
error_setg(errp, "Cannot find block backend %s", id);
@@ -3562,6 +3569,7 @@ void qmp_x_blockdev_del(bool has_id, const char *id,
}
if (blk) {
+ monitor_remove_blk(blk);
blk_unref(blk);
} else {
QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index ee36f93..9a3d8db 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -74,6 +74,8 @@ BlockBackend *blk_by_name(const char *name);
bool blk_name_taken(const char *name);
BlockBackend *blk_next(BlockBackend *blk);
BlockBackend *blk_next_inserted(BlockBackend *blk);
+void monitor_add_blk(BlockBackend *blk);
+void monitor_remove_blk(BlockBackend *blk);
BlockDriverState *blk_bs(BlockBackend *blk);
void blk_remove_bs(BlockBackend *blk);
--
2.6.2
