Commit 12fa4af6 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

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: default avatarKevin Wolf <kwolf@redhat.com>
Acked-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
parent c8f6d58e

block.c

+23 −7
Original line number Diff line number Diff line
@@ -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:

block/commit.c

+7 −7
Original line number Diff line number Diff line
@@ -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);

block/mirror.c

+6 −1
Original line number Diff line number Diff line
@@ -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;

            }

        }

    }

block/stream.c

+8 −1
Original line number Diff line number Diff line
@@ -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 */

block/vvfat.c

+1 −1
Original line number Diff line number Diff line
@@ -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;