Please How do I calculate the offset of a file within a ext3 partition

[William Tambe]

Thank you for warning me, I am already using a specific file as my swap, 
so I had already done mkswap on it.
I only wanted to be able suspend on it and resume from it using swsusp.
To do that I needed to give to the kernel as arguments the following:
resume=<swap_file_partition> resume_offset=<swap_file_header_offset>

So I had to figure out a way to find out where the header of my swap 
file was.
I haven't tried it yet, I rather want to backup my file first, in case 
something wrong happen.

Sincerely,
William Tambe

Theodore Tso wrote:
> On Sun, Jul 22, 2007 at 08:07:31PM -0500, William Tambe wrote:
>> Thank you for your response, but one more question, does this logical 
>> block 0 hold the header of the file, if not where is located the header 
>> of a file in a ext3 filesystem.
>>
>> The reason why I need to know that is because I wish to use swsusp on my 
>> swap-file so I really need to know the location of the file's swap header.
> 
> The swap header is located at the beginning of the file, so yes, that
> would be found in block 0 of the file.
> 
> The bugger question is what are you *doing*?  If you're just trying to
> enable swsusp, you should need to be using debugfs to find the block
> number and then manually editing the swap header.  The swap file
> should have been set up correctly before you started using it, or if
> you want to initialize a new swap-file, you can use the mkswap
> command.  If you're needing to manually edit the swap header, you're
> almost certainly doing something wrong....
> 
> 						- Ted
>