From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41223) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aVjrq-0004P1-0L for qemu-devel@nongnu.org; Tue, 16 Feb 2016 12:56:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aVjro-0002to-Tl for qemu-devel@nongnu.org; Tue, 16 Feb 2016 12:56:53 -0500 From: Paolo Bonzini Date: Tue, 16 Feb 2016 18:56:23 +0100 Message-Id: <1455645388-32401-12-git-send-email-pbonzini@redhat.com> In-Reply-To: <1455645388-32401-1-git-send-email-pbonzini@redhat.com> References: <1455645388-32401-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 11/16] sheepdog: disable dataplane List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, stefanha@redhat.com sheepdog has some calls to aio_poll that are hard to eliminate, for example in sd_sheepdog_goto's call to do_req. Since I don't have means to test sheepdog well, disable dataplane altogether for this driver. Signed-off-by: Paolo Bonzini --- block/sheepdog.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/block/sheepdog.c b/block/sheepdog.c index a0098c1..e2ab946 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -357,6 +357,7 @@ struct SheepdogAIOCB { typedef struct BDRVSheepdogState { BlockDriverState *bs; AioContext *aio_context; + Error *blocker; SheepdogInode inode; @@ -1416,6 +1417,21 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags, Error *local_err = NULL; const char *filename; + /* sd_snapshot_goto does blocking operations that call aio_poll + * (through do_req). This can cause races with iothread: + * + * main thread I/O thread + * ----------------- ------------------ + * while(srco.finished == false) + * aio_poll(..., true) + * srco.finished = true + * aio_poll(..., true) + * + * Now aio_poll potentially blocks forever. + */ + error_setg(&s->blocker, "sheepdog does not support iothreads"); + bdrv_op_block(bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker); + s->bs = bs; s->aio_context = bdrv_get_aio_context(bs); @@ -1950,6 +1966,9 @@ static void sd_close(BlockDriverState *bs) false, NULL, NULL, NULL); closesocket(s->fd); g_free(s->host_spec); + + bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker); + error_free(s->blocker); } static int64_t sd_getlength(BlockDriverState *bs) -- 2.5.0