guix gc: Add '--free-space'.

* guix/scripts/gc.scm (show-help, %options): Add '--free-space'.
(guix-gc)[ensure-free-space]: New procedure.
Handle '--free-space'.

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index ab07d1066e1..6d64772262a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -1974,6 +1974,15 @@ suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
 
 When @var{min} is omitted, collect all the garbage.
 
+@item --free-space=@var{free}
+@itemx -F @var{free}
+Collect garbage until @var{free} space is available under
+@file{/gnu/store}, if possible; @var{free} denotes storage space, such
+as @code{500MiB}, as described above.
+
+When @var{free} or more is already available in @file{/gnu/store}, do
+nothing and exit immediately.
+
 @item --delete
 @itemx -d
 Attempt to delete all the store files and directories specified as