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authorStefan Hajnoczi <stefanha@redhat.com>2014-06-17 14:32:05 +0800
committerKevin Wolf <kwolf@redhat.com>2014-06-27 18:20:29 +0200
commit13344f3a17e0a785c0eb8e36f69518f21aa8a91a (patch)
treec976718dcb484d41f0db5786fd452eed821043b9
parentac46821f2c6eb0617ac911daff111cbc30a4c40c (diff)
block: acquire AioContext in qmp_query_blockstats()
Make query-blockstats safe for dataplane by acquiring the BlockDriverState's AioContext. This ensures that the dataplane IOThread and the main loop's monitor code do not race. Note the assumption that acquiring the drive's BDS AioContext also protects ->file and ->backing_hd. This assumption is made by other aio_context_acquire() callers too. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Tested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/qapi.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/block/qapi.c b/block/qapi.c
index aeabaaf85c..f44f6b4012 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -360,7 +360,11 @@ BlockStatsList *qmp_query_blockstats(Error **errp)
while ((bs = bdrv_next(bs))) {
BlockStatsList *info = g_malloc0(sizeof(*info));
+ AioContext *ctx = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(ctx);
info->value = bdrv_query_stats(bs);
+ aio_context_release(ctx);
*p_next = info;
p_next = &info->next;