From 12fa4af61fb2a08b156134c3b6717534c637c995 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 17 Feb 2017 20:42:32 +0100 Subject: block: Add Error parameter to bdrv_set_backing_hd() Not all callers of bdrv_set_backing_hd() know for sure that attaching the backing file will be allowed by the permission system. Return the error from the function rather than aborting. Signed-off-by: Kevin Wolf Acked-by: Fam Zheng Reviewed-by: Max Reitz --- block.c | 30 +++++++++++++++++++++++------- block/commit.c | 14 +++++++------- block/mirror.c | 7 ++++++- block/stream.c | 9 ++++++++- block/vvfat.c | 2 +- include/block/block.h | 3 ++- 6 files changed, 47 insertions(+), 18 deletions(-) diff --git a/block.c b/block.c index 74ac7dcf74..6440b61be6 100644 --- a/block.c +++ b/block.c @@ -1883,7 +1883,8 @@ static void bdrv_parent_cb_resize(BlockDriverState *bs) * Sets the backing file link of a BDS. A new reference is created; callers * which don't need their own reference any more must call bdrv_unref(). */ -void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, + Error **errp) { if (backing_hd) { bdrv_ref(backing_hd); @@ -1897,9 +1898,12 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) bs->backing = NULL; goto out; } - /* FIXME Error handling */ + bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing, - &error_abort); + errp); + if (!bs->backing) { + bdrv_unref(backing_hd); + } out: bdrv_refresh_limits(bs, NULL); @@ -1983,8 +1987,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, /* Hook up the backing file link; drop our reference, bs owns the * backing_hd reference now */ - bdrv_set_backing_hd(bs, backing_hd); + bdrv_set_backing_hd(bs, backing_hd, &local_err); bdrv_unref(backing_hd); + if (local_err) { + ret = -EINVAL; + goto free_exit; + } qdict_del(parent_options, bdref_key); @@ -2818,7 +2826,7 @@ static void bdrv_close(BlockDriverState *bs) bs->drv->bdrv_close(bs); bs->drv = NULL; - bdrv_set_backing_hd(bs, NULL); + bdrv_set_backing_hd(bs, NULL, &error_abort); if (bs->file != NULL) { bdrv_unref_child(bs, bs->file); @@ -2927,7 +2935,8 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) bdrv_ref(bs_top); change_parent_backing_link(bs_top, bs_new); - bdrv_set_backing_hd(bs_new, bs_top); + /* FIXME Error handling */ + bdrv_set_backing_hd(bs_new, bs_top, &error_abort); bdrv_unref(bs_top); /* bs_new is now referenced by its new parents, we don't need the @@ -3075,6 +3084,7 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, BlockDriverState *base, const char *backing_file_str) { BlockDriverState *new_top_bs = NULL; + Error *local_err = NULL; int ret = -EIO; if (!top->drv || !base->drv) { @@ -3107,7 +3117,13 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, if (ret) { goto exit; } - bdrv_set_backing_hd(new_top_bs, base); + + bdrv_set_backing_hd(new_top_bs, base, &local_err); + if (local_err) { + ret = -EPERM; + error_report_err(local_err); + goto exit; + } ret = 0; exit: diff --git a/block/commit.c b/block/commit.c index 1e0f5318a4..22a0a4db98 100644 --- a/block/commit.c +++ b/block/commit.c @@ -121,7 +121,7 @@ static void commit_complete(BlockJob *job, void *opaque) * filter driver from the backing chain. Do this as the final step so that * the 'consistent read' permission can be granted. */ if (remove_commit_top_bs) { - bdrv_set_backing_hd(overlay_bs, top); + bdrv_set_backing_hd(overlay_bs, top, &error_abort); } } @@ -316,8 +316,8 @@ void commit_start(const char *job_id, BlockDriverState *bs, goto fail; } - bdrv_set_backing_hd(commit_top_bs, top); - bdrv_set_backing_hd(overlay_bs, commit_top_bs); + bdrv_set_backing_hd(commit_top_bs, top, &error_abort); + bdrv_set_backing_hd(overlay_bs, commit_top_bs, &error_abort); s->commit_top_bs = commit_top_bs; bdrv_unref(commit_top_bs); @@ -390,7 +390,7 @@ fail: blk_unref(s->top); } if (commit_top_bs) { - bdrv_set_backing_hd(overlay_bs, top); + bdrv_set_backing_hd(overlay_bs, top, &error_abort); } block_job_unref(&s->common); } @@ -451,8 +451,8 @@ int bdrv_commit(BlockDriverState *bs) goto ro_cleanup; } - bdrv_set_backing_hd(commit_top_bs, backing_file_bs); - bdrv_set_backing_hd(bs, commit_top_bs); + bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort); + bdrv_set_backing_hd(bs, commit_top_bs, &error_abort); ret = blk_insert_bs(backing, backing_file_bs, &local_err); if (ret < 0) { @@ -532,7 +532,7 @@ ro_cleanup: blk_unref(backing); if (backing_file_bs) { - bdrv_set_backing_hd(bs, backing_file_bs); + bdrv_set_backing_hd(bs, backing_file_bs, &error_abort); } bdrv_unref(commit_top_bs); blk_unref(src); diff --git a/block/mirror.c b/block/mirror.c index 869212daac..8497e0db83 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -503,6 +503,7 @@ static void mirror_exit(BlockJob *job, void *opaque) BlockDriverState *src = s->source; BlockDriverState *target_bs = blk_bs(s->target); BlockDriverState *mirror_top_bs = s->mirror_top_bs; + Error *local_err = NULL; /* Make sure that the source BDS doesn't go away before we called * block_job_completed(). */ @@ -516,7 +517,11 @@ static void mirror_exit(BlockJob *job, void *opaque) if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { BlockDriverState *backing = s->is_none_mode ? src : s->base; if (backing_bs(target_bs) != backing) { - bdrv_set_backing_hd(target_bs, backing); + bdrv_set_backing_hd(target_bs, backing, &local_err); + if (local_err) { + error_report_err(local_err); + data->ret = -EPERM; + } } } diff --git a/block/stream.c b/block/stream.c index b9c2f43c57..0113710845 100644 --- a/block/stream.c +++ b/block/stream.c @@ -68,6 +68,7 @@ static void stream_complete(BlockJob *job, void *opaque) StreamCompleteData *data = opaque; BlockDriverState *bs = blk_bs(job->blk); BlockDriverState *base = s->base; + Error *local_err = NULL; if (!block_job_is_cancelled(&s->common) && data->reached_end && data->ret == 0) { @@ -79,9 +80,15 @@ static void stream_complete(BlockJob *job, void *opaque) } } data->ret = bdrv_change_backing_file(bs, base_id, base_fmt); - bdrv_set_backing_hd(bs, base); + bdrv_set_backing_hd(bs, base, &local_err); + if (local_err) { + error_report_err(local_err); + data->ret = -EPERM; + goto out; + } } +out: /* Reopen the image back in read-only mode if necessary */ if (s->bs_flags != bdrv_get_flags(bs)) { /* Give up write permissions before making it read-only */ diff --git a/block/vvfat.c b/block/vvfat.c index 72b482cb1f..aa61c329e7 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -3041,7 +3041,7 @@ static int enable_write_target(BlockDriverState *bs, Error **errp) &error_abort); *(void**) backing->opaque = s; - bdrv_set_backing_hd(s->bs, backing); + bdrv_set_backing_hd(s->bs, backing, &error_abort); bdrv_unref(backing); return 0; diff --git a/include/block/block.h b/include/block/block.h index 07f7561886..eac286124d 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -247,7 +247,8 @@ BdrvChild *bdrv_open_child(const char *filename, BlockDriverState* parent, const BdrvChildRole *child_role, bool allow_none, Error **errp); -void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd); +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, + Error **errp); int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, const char *bdref_key, Error **errp); BlockDriverState *bdrv_open(const char *filename, const char *reference, -- cgit v1.2.3