[Bug-ddrescue] RFE: output the list of bablocks suitable for e2fsck -L

[Valerio Messina]

hi,
first of all, thanks for GNU ddrescue, it recover almost all my 160 GB
2.5" disk. Only 84 zones, 150 sectors, 75 KB remain unreadable, still
retrying with -r9 -d, will see ...

Now that I got a rescued image, I need/want to discover which files are
allocated to bad sectors, and so are damaged.
I saw the proposed solution with hashed files on help page:
http://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html#Fill-Mode
in "8 Fill Mode" section, after Example 3.
This surely work independently of the file system used, but I think it
is slow and complicated.

In case of a know file system type, but almost all use block size of
4096, can be useful to output the list of badblock only.
This list should be in a format suitable for commands like:
e2fsck -vf -L badblocklist.txt /dev/sdaX
so one block number per line, in decimal format, like the output of
badblocks.
The block size should be a parameter to ddrescue, when this output list
is requested, to output the correct block number (like badblocks -b).
4096 can be the default.

This let fsck the imagefile in loop, and simply discover which files are
damaged.

thanks,
Valerio