From f94dc3b414028bc762f51ea66c170276130d5f8a Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Wed, 22 May 2019 19:03:47 +0200 Subject: [PATCH] block/mirror: Fix child permissions We cannot use bdrv_child_try_set_perm() to give up all restrictions on the child edge, and still have bdrv_mirror_top_child_perm() request BLK_PERM_WRITE. Fix this by making bdrv_mirror_top_child_perm() return 0/BLK_PERM_ALL when we want to give up all permissions, and replacing bdrv_child_try_set_perm() by bdrv_child_refresh_perms(). The bdrv_child_try_set_perm() before removing the node with bdrv_replace_node() is then unnecessary. No permissions have changed since the previous invocation of bdrv_child_try_set_perm(). Signed-off-by: Max Reitz Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/mirror.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index b5878ba574..d17be4cdbc 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -85,6 +85,7 @@ typedef struct MirrorBlockJob { typedef struct MirrorBDSOpaque { MirrorBlockJob *job; + bool stop; } MirrorBDSOpaque; struct MirrorOp { @@ -656,8 +657,9 @@ static int mirror_exit_common(Job *job) /* We don't access the source any more. Dropping any WRITE/RESIZE is * required before it could become a backing file of target_bs. */ - bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, - &error_abort); + bs_opaque->stop = true; + bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, + &error_abort); if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { BlockDriverState *backing = s->is_none_mode ? src : s->base; if (backing_bs(target_bs) != backing) { @@ -704,13 +706,12 @@ static int mirror_exit_common(Job *job) g_free(s->replaces); bdrv_unref(target_bs); - /* Remove the mirror filter driver from the graph. Before this, get rid of + /* + * Remove the mirror filter driver from the graph. Before this, get rid of * the blockers on the intermediate nodes so that the resulting state is - * valid. Also give up permissions on mirror_top_bs->backing, which might - * block the removal. */ + * valid. + */ block_job_remove_all_bdrv(bjob); - bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, - &error_abort); bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); /* We just changed the BDS the job BB refers to (with either or both of the @@ -1459,6 +1460,18 @@ static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { + MirrorBDSOpaque *s = bs->opaque; + + if (s->stop) { + /* + * If the job is to be stopped, we do not need to forward + * anything to the real image. + */ + *nperm = 0; + *nshared = BLK_PERM_ALL; + return; + } + /* Must be able to forward guest writes to the real image */ *nperm = 0; if (perm & BLK_PERM_WRITE) { @@ -1681,8 +1694,9 @@ fail: job_early_fail(&s->common.job); } - bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, - &error_abort); + bs_opaque->stop = true; + bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, + &error_abort); bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); bdrv_unref(mirror_top_bs); -- 2.11.0