[Bug-ddrescue] Fill mode does not work if input_position is greater than file size

[Christian Franke]

Hi,

when using options -i and -o to recover only part of a disk to a file, 
-F cannot be used to fill the bad blocks later from a small file.

Example:

1. Recover partition at LBA 10000000-11999999 to a file:

# ddrescue -i 10000000b -s 2000000b -o 0 bad_disk file.img file.log


2. Mark bad blocks in the image file with some data from a small file:

# ddrescue -i 10000000b -s 2000000b -o 0 -F - fill_file file.img file.log
ddrescue: can't start reading at pos 5120000000
ddrescue: input file is only 20 bytes long.

The -i is necessary, because ddrescue records the original physical 
offsets in the logfile.


I would suggest to start the input file at (input_position % input_size) 
when -F is specified.

Hmm...would it make sense the store the input/output_position offset in 
the logfile also?

Regards,
   Christian

PS: Just testing 1.7-pre2 on Cygwin with a real world bad disk with ~100 
bad blocks and failed SMART status (out of spare blocks). Looks good, 
~20 blocks recovered in the last few hours :-)