bug#59185: Trouble mounting recursive file systems in containers
Ludovic Courtès writes: > Ricardo Wurmus skribis: > >> yes, mounting with MS_REC seems sensible. Not mounting with MS_REC is >> also responsible for a couple of errors e.g. when trying to map / inside >> the container (when / has other bind mounts). > > Having reread mount(2), bind-mounting with MS_REC by default seems like > a reasonable choice, indeed. Great. I’ve pushed this with commit c585b4bc68813a351d6a87d19b9adf4041506355. -- Ricardo
bug#59185: Trouble mounting recursive file systems in containers
Hi, Ricardo Wurmus skribis: > yes, mounting with MS_REC seems sensible. Not mounting with MS_REC is > also responsible for a couple of errors e.g. when trying to map / inside > the container (when / has other bind mounts). Having reread mount(2), bind-mounting with MS_REC by default seems like a reasonable choice, indeed. Ludo’.
bug#59185: Trouble mounting recursive file systems in containers
Hi Morgan, yes, mounting with MS_REC seems sensible. Not mounting with MS_REC is also responsible for a couple of errors e.g. when trying to map / inside the container (when / has other bind mounts). Here’s a patch that works for me: >From 806969ad86038052bf4d0dd2755617beaaa33cb6 Mon Sep 17 00:00:00 2001 From: Ricardo Wurmus Date: Sat, 19 Nov 2022 23:16:52 +0100 Subject: [PATCH] WIP --- gnu/build/file-systems.scm | 2 +- guix/build/syscalls.scm| 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm index 15b8f73312..66ca22d6ea 100644 --- a/gnu/build/file-systems.scm +++ b/gnu/build/file-systems.scm @@ -1127,7 +1127,7 @@ (define (mount-flags->bit-mask flags) (('read-only rest ...) (logior MS_RDONLY (loop rest))) (('bind-mount rest ...) - (logior MS_BIND (loop rest))) + (logior MS_REC (logior MS_BIND (loop rest (('no-suid rest ...) (logior MS_NOSUID (loop rest))) (('no-dev rest ...) diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm index 61926beb80..2a12567b15 100644 --- a/guix/build/syscalls.scm +++ b/guix/build/syscalls.scm @@ -51,6 +51,7 @@ (define-module (guix build syscalls) MS_RELATIME MS_BIND MS_MOVE +MS_REC MS_SHARED MS_LAZYTIME MNT_FORCE @@ -541,6 +542,7 @@ (define MS_NOATIME 1024) (define MS_NODIRATIME 2048) (define MS_BIND4096) (define MS_MOVE8192) +(define MS_REC16384) (define MS_SHARED 1048576) (define MS_RELATIME 2097152) (define MS_STRICTATIME 16777216) -- 2.36.1 -- Ricardo
bug#59185: Trouble mounting recursive file systems in containers
Hello! So I was trying to mount /run/user/1000 in a container so it would have access to all my wayland sockets and such when I got a very cryptic error message. I was trying something like this: guix shell --share=/run/user/1000 -C coreutils After far too long tracking down the issue, it turns out that the directory had submounts within it meaning that the MS_REC flag is required to bind mount it. My /run/user/1000 only had a submount because xdg-document-portal was making one. To test this yourself you can run `mount` to find something with some submounts. I think /sys/fs might fail for me for the same reason. Now I have no clue what we should do to enable this use case. Maybe we should allow users to specify mount options using something like this? guix shell -C --mount=rbind,ro=/run/user/1000 Maybe we could always bind with the recursive flag? Thanks, Morgan