Bug#868900: iso-scan: should be able to copy the ISO into RAM before mount
Source: iso-scan
Version: 1.57
Severity: wishlist
Tags: patch
When you use an ISO image stored on a disk, it makes it impossible to
re-use that disk in the installation process (e.g. for automatic
partitioning).
In order to avoid this limitation, I would like iso-scan to be able
to copy the ISO image into RAM and to mount it from there. The attached
patch implements precisely when the debconf question "iso-scan/copy_iso_to_ram"
returns true.
It would be nice to see this merged (the patch applies cleanly on top
of the one in #868859, but you can also merge it separately if you drop
the changelog entry).
Let me know if there's anything to improve before it's ready to be merged
(notably on the debconf template, etc.).
Cheers,
-- System Information:
Debian Release: buster/sid
APT prefers oldoldstable
APT policy: (500, 'oldoldstable'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.9.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
--
Raphaël Hertzog ◈ Debian Developer
Support Debian LTS: https://www.freexian.com/services/debian-lts.html
Learn to master Debian: https://debian-handbook.info/get/
>From f036be16012d1004053fa977258c842b1d9eed47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rapha=C3=ABl=20Hertzog?= <hertzog@debian.org>
Date: Wed, 19 Jul 2017 16:20:38 +0200
Subject: [PATCH] Offer possibility to copy ISO to RAM before mount
The iso-scan/copy_iso_to_ram debconf question controls this new
feature. It defaults to false for backwards compatibility and also
because it can only be safely enabled when the amount of RAM is
sufficient to host a full copy of the image.
---
debian/changelog | 3 +++
debian/iso-scan.postinst | 19 ++++++++++++++++++-
debian/iso-scan.templates | 14 ++++++++++++++
3 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/debian/changelog b/debian/changelog
index 6abd1db..18c47c8 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -2,6 +2,9 @@ iso-scan (1.58) UNRELEASED; urgency=medium
* Detect LVM logical volumes so that they can be used to find the ISO image
that we are looking for.
+ * Copy the ISO image into RAM before mounting it when debconf question
+ iso-scan/copy_iso_to_ram is true. This makes it possible to use the disk
+ that provided the ISO image for (automatic) partitioning.
-- Raphaël Hertzog <hertzog@debian.org> Tue, 18 Jul 2017 16:58:13 +0200
diff --git a/debian/iso-scan.postinst b/debian/iso-scan.postinst
index e34f329..1109ba5 100755
--- a/debian/iso-scan.postinst
+++ b/debian/iso-scan.postinst
@@ -203,9 +203,26 @@ use_this_iso () {
local iso_device=$2
local RET
+ db_input low iso-scan/copy_iso_to_ram || true
+ db_go
+ db_get iso-scan/copy_iso_to_ram
+
mount -t auto -o ro $iso_device /hd-media 2>/dev/null
cd /hd-media
- mount -t iso9660 -o loop,ro,exec $iso_to_try /cdrom 2>/dev/null
+
+ if [ "$RET" = false ]; then
+ # Direct mount
+ log "Mounting /hd-media/$iso_to_try on /cdrom"
+ mount -t iso9660 -o loop,ro,exec $iso_to_try /cdrom 2>/dev/null
+ else
+ # We copy the ISO to RAM before mounting it
+ log "Copying /hd-media/$iso_to_try to /installer.iso"
+ cp $iso_to_try /installer.iso
+ log "Mounting /installer.iso on /cdrom"
+ mount -t iso9660 -o loop,ro,exec /installer.iso /cdrom 2>/dev/null
+ cd /
+ umount /hd-media
+ fi
analyze_cd
diff --git a/debian/iso-scan.templates b/debian/iso-scan.templates
index e3a23d1..76ba00a 100644
--- a/debian/iso-scan.templates
+++ b/debian/iso-scan.templates
@@ -126,3 +126,17 @@ _Description: Is ISO file ${FILENAME} the correct image for installation?
.
If multiple ISO files exist on the same installer drive,
you may select which one you want to use.
+
+Template: iso-scan/copy_iso_to_ram
+Type: boolean
+Default: false
+# :sl3:
+_Description: Copy the ISO image into RAM before mounting it?
+ If you don't copy the ISO image into RAM, then the disk hosting
+ the ISO image cannot be partitioned as the installer will be
+ actively using it.
+ .
+ However copying the ISO into RAM might not be possible if the ISO image
+ is larger than the amount of RAM available. If the amount of RAM
+ remaining after copy is too low, it might cause other unexpected failures
+ later in the installation process.
--
2.13.3
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