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Re: Some concern about the journal support
From: |
Bean |
Subject: |
Re: Some concern about the journal support |
Date: |
Sun, 15 Jun 2008 00:17:57 +0800 |
On Sat, Jun 14, 2008 at 7:43 PM, Robert Millan <address@hidden> wrote:
> On Fri, Jun 13, 2008 at 04:14:17PM -0400, Pavel Roskin wrote:
>>
>> Your patch should fix the issue with hardcoding block locations, if I
>> understand correctly.
>
> Notice that hardcoding block locations only happens when core.img doesn't
> fit in the post-mbr area.
>
> Which is a situation we should try to avoid by making core.img small, which
> means a smaller ext2.mod also helps ;-)
>
>> I was asking where journal support would be beneficial in userspace at
>> all. And it has to be asked if journal support is useful at the boot
>> time.
>>
>> We have some code that is hard to get right and hard to test. Yet it
>> will be run every time an unclean ext3 filesystem is found at the boot
>> time. What are we gaining? What is the situation where using the
>> journal is beneficial? How likely is it to happen? Is it possible that
>> we may be better off not using the journal? How likely is that?
>>
>> The standard use of the journal is to make the filesystem consistent
>> after an unclean shutdown without having to run a time-consuming fsck.
>> Since grub is not writing anything to the disk, consistency is not
>> really important. What's important got grub is reliability and ability
>> to access all files on the filesystem.
>>
>> > btw, the reiserfs driver is a little strange, it don't follow the
>> > normal path of grub_fshelp_read_file, perhaps we just disable the
>> > journal at the moment.
>>
>> My impression is that we need to make journal support experimental and
>> disabled by default for both ext3 and reiserfs. It should only be
>> enabled by default if there are a good arguments why it's useful and a
>> testsuite to prove that it's reliable.
>
> How about a separate module?
Hi,
It's a good idea, perhaps I can add a journal layer on top of disk to
do the mapping transparently.
--
Bean
- Re: Some concern about the journal support, (continued)
- Re: Some concern about the journal support, Pavel Roskin, 2008/06/13
- Re: Some concern about the journal support, Robert Millan, 2008/06/14
- Re: Some concern about the journal support,
Bean <=
- Re: Some concern about the journal support, Bean, 2008/06/14
- Re: Some concern about the journal support, Robert Millan, 2008/06/14
- Re: Some concern about the journal support, Bean, 2008/06/14
- Re: Some concern about the journal support, Robert Millan, 2008/06/14
- Re: Some concern about the journal support, Javier MartÃn, 2008/06/14
- Re: Some concern about the journal support, Pavel Roskin, 2008/06/15
- Re: Some concern about the journal support, Bean, 2008/06/16