When bitmaps are persistent, they may incur a disk read or write when bitmaps
are added or removed. For configurations like virtio-dataplane, failing to
acquire this lock will abort QEMU when disk IO occurs.
We used to acquire aio_context as part of the bitmap lookup, so re-introduce
the lock for just the cases that have an IO penalty. Commit 2119882c removed
these locks, and I failed to notice this when we committed fd5ae4cc, so this
has been broken since persistent bitmaps were introduced.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1672010
Reported-By: Aihua Liang
Signed-off-by: John Snow
---
v5: I'm having a really bad day. This version actually has the semicolon.
---
blockdev.c | 26 --
1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index fb18e9c975..8714ad2702 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2820,6 +2820,7 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
{
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
+AioContext *aio_context = NULL;
if (!name || name[0] == '\0') {
error_setg(errp, "Bitmap name cannot be empty");
@@ -2854,15 +2855,17 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
disabled = false;
}
-if (persistent &&
-!bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp))
-{
-return;
+if (persistent) {
+aio_context = bdrv_get_aio_context(bs);
+aio_context_acquire(aio_context);
+if (!bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp)) {
+goto out;
+}
}
bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
if (bitmap == NULL) {
-return;
+goto out;
}
if (disabled) {
@@ -2870,6 +2873,10 @@ void qmp_block_dirty_bitmap_add(const char *node, const
char *name,
}
bdrv_dirty_bitmap_set_persistance(bitmap, persistent);
+ out:
+if (aio_context) {
+aio_context_release(aio_context);
+}
}
void qmp_block_dirty_bitmap_remove(const char *node, const char *name,
@@ -2878,6 +2885,7 @@ void qmp_block_dirty_bitmap_remove(const char *node,
const char *name,
BlockDriverState *bs;
BdrvDirtyBitmap *bitmap;
Error *local_err = NULL;
+AioContext *aio_context = NULL;
bitmap = block_dirty_bitmap_lookup(node, name, , errp);
if (!bitmap || !bs) {
@@ -2892,14 +2900,20 @@ void qmp_block_dirty_bitmap_remove(const char *node,
const char *name,
}
if (bdrv_dirty_bitmap_get_persistance(bitmap)) {
+aio_context = bdrv_get_aio_context(bs);
+aio_context_acquire(aio_context);
bdrv_remove_persistent_dirty_bitmap(bs, name, _err);
if (local_err != NULL) {
error_propagate(errp, local_err);
-return;
+goto out;
}
}
bdrv_release_dirty_bitmap(bs, bitmap);
+ out:
+if (aio_context) {
+aio_context_release(aio_context);
+}
}
/**
--
2.17.2
