Re: Compatible fstat()

["Theodore Ts'o" <tytso@mit.edu>]

On Tue, Nov 08, 2005 at 02:12:24PM -0500, Parag Warudkar wrote:
> 
> On Nov 8, 2005, at 1:49 PM, Theodore Ts'o wrote:
> 
> >e2fsprogs falls back to using a
> >binary search using SEEK_SET to find the device size.
> 
> Binary search of what? 

Of the device size; it doubles the guessed size of the disk until
lseek+read returns an error, and then uses binary search to figure out
the size of the disk.  I did this because it works on pretty much any
OS.

>  I tried to read the relevant code in getsize.c  
> but apart from suspecting that the binary search thing might be  
> specific to ext2fs I didn't quite understand what's going on in the  
> code.  (Will it work irrespective of the file system presence on the  
> device?)

Yes, it works irrespective of what's on the disk.  In fact, if the
Linux-specific ioctl's are not available, it's what will be used by
mke2fs to figure out the size of the device.

					- Ted