memfd: improve error messages

This gives more information about the failure.
Additionally 'ENOSYS' returned for a non-Linux platforms instead of
'errno', which is not initilaized in this case.

Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190311135850.6537-5-i.maximets@samsung.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

diff --git a/util/memfd.c b/util/memfd.c
index 393d23da96b2635d780f9ff4634dc6808b645dbd..00334e5b218fa4b7ee19ecfab6687a6aaceffe12 100644 (file)
--- a/util/memfd.c
+++ b/util/memfd.c
@@ -71,14 +71,18 @@ int qemu_memfd_create(const char *name, size_t size, bool hugetlb,
     }
     mfd = memfd_create(name, flags);
     if (mfd < 0) {
+        error_setg_errno(errp, errno,
+                         "failed to create memfd with flags 0x%x", flags);
         goto err;
     }
 
     if (ftruncate(mfd, size) == -1) {
+        error_setg_errno(errp, errno, "failed to resize memfd to %zu", size);
         goto err;
     }
 
     if (seals && fcntl(mfd, F_ADD_SEALS, seals) == -1) {
+        error_setg_errno(errp, errno, "failed to add seals 0x%x", seals);
         goto err;
     }
 
@@ -88,8 +92,9 @@ err:
     if (mfd >= 0) {
         close(mfd);
     }
+#else
+    error_setg_errno(errp, ENOSYS, "failed to create memfd");
 #endif
-    error_setg_errno(errp, errno, "failed to create memfd");
     return -1;
 }