From 3cc121efe043067f39e07fb061588ac84d03bf3f Mon Sep 17 00:00:00 2001 From: John Snow Date: Wed, 14 Sep 2016 20:04:37 +0200 Subject: [PATCH 13/18] block: Inactivate all children RH-Author: John Snow Message-id: <1473883477-31953-4-git-send-email-jsnow@redhat.com> Patchwork-id: 72333 O-Subject: [RHEV-7.3 qemu-kvm-rhev PATCH 3/3] block: Inactivate all children Bugzilla: 1355927 RH-Acked-by: Fam Zheng RH-Acked-by: Kevin Wolf RH-Acked-by: Miroslav Rezanina From: Fam Zheng Currently we only inactivate the top BDS. Actually bdrv_inactivate should be the opposite of bdrv_invalidate_cache. Recurse into the whole subtree instead. Because a node may have multiple parents, and because once BDRV_O_INACTIVE is set for a node, further writes are not allowed, we cannot interleave flag settings and .bdrv_inactivate calls (that may submit write to other nodes in a graph) within a single pass. Therefore two passes are used here. Signed-off-by: Fam Zheng Signed-off-by: Kevin Wolf (cherry picked from commit aad0b7a0bfbd6d200f617396c0d3b71ac7abfa40) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- block.c | 47 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 11 deletions(-) diff --git a/block.c b/block.c index c5a4391..75afea5 100644 --- a/block.c +++ b/block.c @@ -3262,38 +3262,63 @@ void bdrv_invalidate_cache_all(Error **errp) } } -static int bdrv_inactivate(BlockDriverState *bs) +static int bdrv_inactivate_recurse(BlockDriverState *bs, + bool setting_flag) { + BdrvChild *child; int ret; - if (bs->drv->bdrv_inactivate) { + if (!setting_flag && bs->drv->bdrv_inactivate) { ret = bs->drv->bdrv_inactivate(bs); if (ret < 0) { return ret; } } - bs->open_flags |= BDRV_O_INACTIVE; + QLIST_FOREACH(child, &bs->children, next) { + ret = bdrv_inactivate_recurse(child->bs, setting_flag); + if (ret < 0) { + return ret; + } + } + + if (setting_flag) { + bs->open_flags |= BDRV_O_INACTIVE; + } return 0; } int bdrv_inactivate_all(void) { BlockDriverState *bs = NULL; - int ret; + int ret = 0; + int pass; while ((bs = bdrv_next(bs)) != NULL) { - AioContext *aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(bdrv_get_aio_context(bs)); + } - aio_context_acquire(aio_context); - ret = bdrv_inactivate(bs); - aio_context_release(aio_context); - if (ret < 0) { - return ret; + /* We do two passes of inactivation. The first pass calls to drivers' + * .bdrv_inactivate callbacks recursively so all cache is flushed to disk; + * the second pass sets the BDRV_O_INACTIVE flag so that no further write + * is allowed. */ + for (pass = 0; pass < 2; pass++) { + bs = NULL; + while ((bs = bdrv_next(bs)) != NULL) { + ret = bdrv_inactivate_recurse(bs, pass); + if (ret < 0) { + goto out; + } } } - return 0; +out: + bs = NULL; + while ((bs = bdrv_next(bs)) != NULL) { + aio_context_release(bdrv_get_aio_context(bs)); + } + + return ret; } /**************************************************************/ -- 1.8.3.1