From 13344f3a17e0a785c0eb8e36f69518f21aa8a91a Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 17 Jun 2014 14:32:05 +0800 Subject: [PATCH] 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 Signed-off-by: Fam Zheng Tested-by: Paolo Bonzini Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/qapi.c | 4 ++++ 1 file changed, 4 insertions(+) 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;