On 08/30/2013 06:36 PM, Christian Hesse wrote:
Gerardo Exequiel Pozzi vmlinuz386@yahoo.com.ar on Fri, 2013/08/30 13:01:
On 08/30/2013 06:12 AM, Christian Hesse wrote:
Gerardo Exequiel Pozzi vmlinuz386@yahoo.com.ar on Thu, 2013/08/29 20:01:
Ignore me, was a bad smart answer, since you want to increse the size of the device!
In any case, the semantics of cowfile_size should not be changed. You can add another parameter like grow_ro_dev_size=,
I add a use case for what was completely useless before. (In fact the cow files got bigger, but the resulting device size stayed the same.) Do you really want an new parameter for that? I do not mind, I can change that if desired.
Yes using a new parameter should be more clear.
Done. This parameter only takes affect with values greater than 100.
For my first impression (of what name says), not much clear. What is grow_ro_dev_size=? a percent? In that case a default 100% says: grow ro_dev in 100% -> double ro_dev_size and 0% -> no changes.
also should be ensure the proper device shutdown and persistence.
systemd should disassemble the devices, no? What is needed more?
No, systemd can not stop this complex setup, indeed we can not use the provided shutdown script by mkinitcpio, we are using a own shutdown script.
Ah, looks like I missed to add a file to used_block_devices. Is it ok now? Hope so... Otherwise I have to take a deeper look at the shutdown script.
Maybe, you need to check if all things stopped properly when switch back to initramfs on shutdown.
And what do you refer with persistance? Everything should work just fine given a persistant system is booted with the same parameters.
cow_persistent=P | cow_persistent=N
For this extension, should not use the same directory.
Of course, this "extension" file act as ro-device, will never be modified during runtime.
I create a directory /run/archiso/growspace. cowspace is not touched by my code. Is that ok?
Looking at the code, growspace files is created on rootfs then deleted on switch-root. Should be on another tmpfs.
But doing in a different way, you can use a dm-zero target instead. Since you never never write to this block device, is just to say "i have a much bigger read-only device".
We are reaching 3.11 and still no "overlayfs" :( (was promised for 3.10, 3.2, ...)
Well, yes... On the other hand I really like the idea to solve this with device mapper. ;)
If at some point linux implements an overlayfs, and I still alive ;), I want to move back to filesystem solution instead of block-based like now.
I am fine with that as long as it is upstream linux. ;)
Sure :)
Just thinking about how to integrate the userspace tools and handling for this. I would like to add a new hook that adds the binary files (resize2fs, xfs_growfs, btrfs), so anybody can decide whether or not to include. But where do we call this?
I did not see any real usage of this "extension" inside official image. If you are building a custom image build, why not just create a big filesystem from the start?
Because bigger filesystem has more metadata. Image size would increase for a use case I need only very seldom. I perfer to add some lines of code, having the possibility to grow device and filesystem when needed.
True, but this can be done from another perspective, just create a big file for filesystem, but use few blocks, since squashfs supports sparse files.
To do this in the most trivial way is just adding one line to mkarchiso. Let says: truncate -s 16G ${_fs_img} after "mkfs". (or even better! truncate -s 2T ${_fs_img} :D)
There is only one downside if cowspace should be stored on filesystems that does not support sparse files like FAT cowspace_size= is much more important to be specified now.
This avoid at all this complex logic, what do you think?
Here is my new patch, this also has some code to actually grow the filesystem.
From 7609b2ba1b3b876efc4199d9653b389303cd980a Mon Sep 17 00:00:00 2001 From: Christian Hesse mail@eworm.de Date: Fri, 30 Aug 2013 21:10:44 +0200 Subject: [PATCH 1/1] support growing devices and filesystems
archiso/initcpio/hooks/archiso | 59 ++++++++++++++++++++++++++++++++- archiso/initcpio/install/archiso_growfs | 9 +++++ 2 files changed, 67 insertions(+), 1 deletion(-) create mode 100644 archiso/initcpio/install/archiso_growfs
diff --git a/archiso/initcpio/hooks/archiso b/archiso/initcpio/hooks/archiso index 66a6273..76dcb6e 100644 --- a/archiso/initcpio/hooks/archiso +++ b/archiso/initcpio/hooks/archiso @@ -6,11 +6,27 @@ _mnt_fs() { local img_fullname="${img##*/}"; local img_name="${img_fullname%%.*}" local dm_snap_name="${dm_snap_prefix}_${img_name}"
- local ro_dev ro_dev_size rw_dev
local ro_dev ro_dev_size rw_dev rw_dev_size pad_dev pad_dev_size
ro_dev=$(losetup --find --show --read-only "${img}") echo ${ro_dev} >> /run/archiso/used_block_devices ro_dev_size=$(blockdev --getsz ${ro_dev})
if [[ "${grow_ro_dev_size}" -gt 100 ]]; then
pad_dev_size=$((ro_dev_size/100*grow_ro_dev_size - ro_dev_size))dd of="/run/archiso/growspace/${img_name}.pad" count=0seek=${pad_dev_size} &> /dev/null
pad_dev=$(losetup --find --show --read-only"/run/archiso/growspace/${img_name}.pad")
echo ${pad_dev} >> /run/archiso/used_block_devicesecho -e "0 ${ro_dev_size} linear ${ro_dev} 0\n${ro_dev_size}${pad_dev_size} linear ${pad_dev} 0" | dmsetup create "ro_${dm_snap_name}"
echo $(readlink -f /dev/mapper/${dm_snap_name})/run/archiso/used_block_devices +
ro_dev="/dev/mapper/ro_${dm_snap_name}"ro_dev_size="$((ro_dev_size + pad_dev_size))"rw_dev_size="${ro_dev_size}"msg ":: Device ${dm_snap_name} has been grown, remember to grow yourfilesystem!"
- fi
- if [[ "${cowfile_size}" == "100" ]]; then rw_dev_size=${ro_dev_size} else
@@ -43,6 +59,40 @@ _mnt_fs() { echo $(readlink -f /dev/mapper/${dm_snap_name})
/run/archiso/used_block_devices }
+# args: name, fs_type +_grow_fs() {
- local name="${1}"
- local fs_type="${2}"
- local device="/dev/mapper/${dm_snap_prefix}_${name}"
- case ${aitab_fs_type} in
ext*)if [[ -x /usr/bin/resize2fs ]]; thenmsg ":: Growing ${fs_type} filesystem for ${name}"resize2fs "${device}" >/dev/nullelsemsg ":: Not growing ${name}, userspace tools not available."fi;;xfs)if [[ -x /usr/bin/xfs_growfs ]]; thenmsg ":: Growing ${fs_type} filesystem for ${name}"xfs_growfs "${device}" >/dev/nullelsemsg ":: Not growing ${name}, userspace tools not available."fi;;btrfs)if [[ -x /usr/bin/btrfs ]]; thenmsg ":: Growing ${fs_type} filesystem for ${name}"btrfs resize max "${device}" >/dev/nullelsemsg ":: Not growing ${name}, userspace tools not available."fi;;- esac
+}
# args: /path/to/image_file, mountpoint _mnt_sfs() { local img="${1}" @@ -112,6 +163,7 @@ run_hook() { else cowfile_size=${cowfile_size/%} fi
[[ -z "${grow_ro_dev_size}" ]] && grow_ro_dev_size="100"
if [[ -z "${aitab}" ]]; then aitab="/run/archiso/bootmnt/${archisobasedir}/aitab"
@@ -188,6 +240,10 @@ archiso_mount_handler() { fi mkdir -p "/run/archiso/cowspace/${cow_directory}"
- if [[ "${grow_ro_dev_size}" -gt 100 ]]; then
mkdir -p /run/archiso/growspace- fi
- local aitab_img aitab_mnt aitab_arch aitab_sfs_comp aitab_fs_type
aitab_fs_size while read aitab_img aitab_mnt aitab_arch aitab_sfs_comp aitab_fs_type aitab_fs_size; do [[ "${aitab_img##}" != "${aitab_img}" ]] && continue @@ -195,6 +251,7 @@ archiso_mount_handler() { if [[ "${aitab_fs_type}" != "none" ]]; then _mnt_sfs "/run/archiso/bootmnt/${archisobasedir}/${aitab_arch}/${aitab_img}.fs.sfs" "/run/archiso/sfs/${aitab_img}" _mnt_fs "/run/archiso/sfs/${aitab_img}/${aitab_img}.fs" "${newroot}" "${aitab_mnt}"
[[ "${grow_ro_dev_size}" -gt 100 ]] && _grow_fs "${aitab_img}""${aitab_fs_type}" else _mnt_sfs "/run/archiso/bootmnt/${archisobasedir}/${aitab_arch}/${aitab_img}.sfs" "${newroot}${aitab_mnt}" fi diff --git a/archiso/initcpio/install/archiso_growfs b/archiso/initcpio/install/archiso_growfs new file mode 100644 index 0000000..6334a3c --- /dev/null +++ b/archiso/initcpio/install/archiso_growfs @@ -0,0 +1,9 @@ +#!/bin/bash
+build() {
- add_binary btrfs
- add_binary resize2fs
- add_binary xfs_growfs
+}
+# vim: set ft=sh ts=4 sw=4 et: