DataBlock information Help

[Andreas Dilger]

On 2010-03-18, at 16:48, MirJafar Ali wrote:
> I am using e2fsprogs and found it very nice. I want to know  
> datablocks for a given a given file.
> I was going through the document and did lots of google search, but  
> I am not sure what is the best way to get this information. Which  
> "e2fsprogs" function can give all the datablock IDs. There is one  
> function i.e. ext2fs_block_iterate, but I am not sure how it works.  
> It wasn't clear from the
> document.


If you use "dumpe2fs -c -R 'stat /path/to/file' /dev/XXX", where /path/ 
to/file is the filesystem relative pathname, that will dump all of the  
blocks.

On newer kernels you can also use "filefrag -v" to list the blocks,  
though the output format is less than ideal right now.

Programatically, on a newer kernel you can use the fiemap() API to get  
the list of all blocks for any file, regardless of the filesystem type.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.