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, 12 insertions, 5 deletions

diff --git a/block/file-posix.c b/block/file-posix.c
index 9c0d70170d..1941fb6749 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1411,20 +1411,27 @@ static int raw_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
     struct stat st;
+    int ret;
 
     if (fstat(s->fd, &st)) {
-        return -errno;
+        ret = -errno;
+        error_setg_errno(errp, -ret, "Failed to fstat() the file");
+        return ret;
     }
 
     if (S_ISREG(st.st_mode)) {
         if (ftruncate(s->fd, offset) < 0) {
-            return -errno;
+            ret = -errno;
+            error_setg_errno(errp, -ret, "Failed to resize the file");
+            return ret;
         }
     } else if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
-       if (offset > raw_getlength(bs)) {
-           return -EINVAL;
-       }
+        if (offset > raw_getlength(bs)) {
+            error_setg(errp, "Cannot grow device files");
+            return -EINVAL;
+        }
     } else {
+        error_setg(errp, "Resizing this file is not supported");
         return -ENOTSUP;
     }