[bug#28635] [PATCH 1/2] vm: Add a minimum root size.

[Christopher Baines]

* gnu/system/vm.scm (qemu-image): When guessing the root-size, use a lower
  bound of 20 MiB, otherwise the root file system size is sometimes 0 MiB in
  size.
---
 gnu/system/vm.scm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm
index 78143e4f7..d340a8563 100644
--- a/gnu/system/vm.scm
+++ b/gnu/system/vm.scm
@@ -304,9 +304,12 @@ the image."
                                #:register-closures? #$register-closures?
                                #:system-directory #$os-drv))
                   (root-size  #$(if (eq? 'guess disk-image-size)
-                                    #~(estimated-partition-size
-                                       (map (cut string-append "/xchg/" <>)
-                                            graphs))
+                                    #~(max
+                                       ;; Minimum 20 MiB root size
+                                       (* 20 (expt 2 20))
+                                       (estimated-partition-size
+                                        (map (cut string-append "/xchg/" <>)
+                                             graphs)))
                                     (- disk-image-size
                                        (* 50 (expt 2 20)))))
                   (partitions (list (partition
-- 
2.14.1