As I was working on my container implementation I noticed that 'mount-file-system' doesn't support bind mounting regular files because it assumes that all mount points are directories. This patch fixes that.
>From f94fec6cde3826f20c0d69a45c2aa1928c1d0a78 Mon Sep 17 00:00:00 2001 From: David Thompson <dthomps...@worcester.edu> Date: Sat, 1 Aug 2015 13:43:33 -0400 Subject: [PATCH] build: file-systems: Allow for bind mounting regular files. * gnu/build/file-systems.scm (regular-file?): New procedure. (mount-file-system): Create a regular file instead of a directory when bind mounting a regular file. --- gnu/build/file-systems.scm | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm index c58d23c..f0d6f70 100644 --- a/gnu/build/file-systems.scm +++ b/gnu/build/file-systems.scm @@ -305,6 +305,10 @@ the following: fsck code device) (start-repl))))) +(define (regular-file? file-name) + "Return #t if FILE-NAME is a regular file." + (eq? (stat:type (stat file-name)) 'regular)) + (define (mount-flags->bit-mask flags) "Return the number suitable for the 'flags' argument of 'mount' that corresponds to the symbols listed in FLAGS." @@ -339,7 +343,16 @@ run a file system check." (flags (mount-flags->bit-mask flags))) (when check? (check-file-system source type)) - (mkdir-p mount-point) + + ;; Create the mount point. Most of the time this is a directory, but + ;; in the case of a bind mount, a regular file may be needed. + (if (and (= MS_BIND (logand flags MS_BIND)) + (regular-file? source)) + (begin + (mkdir-p (dirname mount-point)) + (call-with-output-file mount-point (const #t))) + (mkdir-p mount-point)) + (mount source mount-point type flags options) ;; For read-only bind mounts, an extra remount is needed, as per -- 2.4.3
-- David Thompson GPG Key: 0FF1D807