Help : e2fsprogs
christopher.chan at bradbury.edu.hk
Fri Feb 26 05:42:09 UTC 2010
On Friday, February 26, 2010 01:00 PM, MirJafar Ali wrote:
> Hope you will forgive me for asking some very simple question about
> e2fsprogs. I am very new to the kernel as
> well as file system programming.
> My task is to collect superblock, inode, bitmap ( or free list)
> information from ext2/ext3 filesysteam. After searching
> the google, I came to know about e2fsprogs, which I was able to install
> and use at least "dumpe2fs" utility. This
> utility do not provide timestamp of each allocated inode and I am
> thinking of modifying source code of e2fsprogs.
Use stat. However, not all timestamps will necessarily be updated like
when there are mount options to exclude access timestamps
> My two questions are:
> 1. Is it correct to use "dumpe2fs" program and modify for timestamp ?
> 2. I could not understand the main purpose of e2fsprogs. Am I correct
> to assume that this program extract information
> from the existing ext2/ext3 filesystem. Why there are ext2_inode
> datastructure defined in these programs ? Why couldn't
> these programs read existing datastructures of inode ?
ext3 filesystems are readable by the ext2 filesystem driver because
there are no changes to the datastructure. ext3 mainly adds a journal by
reserving inode 8 for the journal (which is why it is best done at
creation time to get sequential blocks allocated) and some other
features that have been tacked on over time.
> 3. Are these user level or kernel level programs ?
It won't be kernel level if you run it on the commandline would it? You
can use a user level program to adjust or manipulate something in the
kernel like using iptables to manipulate netfilter.
> 4. I want to have my own policies of allocatiing datablocks in some
> cylinder group instead of using ext2 default policy ? What
> should I do for that ?
Read ext2/3/4 code? Clone and modify the code, give it another name,
test that on some free space? Oh, go ask on an appropriate list.
> I know, these must be silly questions, but I will learn from your response.
They are silly because you are asking in the WRONG location. This is a
technical support list. Not even a filesystem enthusiasts list let alone
a filesystem developers list.
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