block: Add .bdrv_truncate() error messages

Add missing error messages for the block driver implementations of
.bdrv_truncate(); drop the generic one from block.c's bdrv_truncate().

Since one of these changes touches a mis-indented block in
block/file-posix.c, this patch fixes that coding style issue along the
way.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-5-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/block/qed.c b/block/qed.c
index fa2aeee471..fd76817cbb 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1526,11 +1526,12 @@ static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 
     if (!qed_is_image_size_valid(offset, s->header.cluster_size,
                                  s->header.table_size)) {
+        error_setg(errp, "Invalid image size specified");
         return -EINVAL;
     }
 
-    /* Shrinking is currently not supported */
     if ((uint64_t)offset < s->header.image_size) {
+        error_setg(errp, "Shrinking images is currently not supported");
         return -ENOTSUP;
     }
 
@@ -1539,6 +1540,7 @@ static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
     ret = qed_write_header_sync(s);
     if (ret < 0) {
         s->header.image_size = old_image_size;
+        error_setg_errno(errp, -ret, "Failed to update the image size");
     }
     return ret;
 }