Sorry for my poor english.

In samba3.0.2rc2 smbd/dosmode.c/dos_mode(), I think below SPARSE attribute code 
is not good for Linux, because linux st_blocks gives the size of the file in 
512-byte blocks. 

>#if defined (HAVE_STAT_ST_BLOCKS) && defined (HAVE_STAT_ST_BLKSIZE)
>    if (sbuf->st_size > sbuf->st_blocks * (SMB_OFF_T)sbuf->st_blksize) {
>        result |= FILE_ATTRIBUTE_SPARSE;
>    }
>#endif

Linux manpage of stat says :
----------------------------------------------------------------
The value st_size gives the size of the file (if it is a regular 
file or a symlink) in bytes. The size of a symlink is the length 
of the pathname it contains, without trailing NUL. 

The value st_blocks gives the size of the file in 512-byte blocks. 
(This may be smaller than st_size/512 e.g. when the file has holes.)

The value st_blksize gives the "preferred" blocksize for efficient 
file system I/O. (Writing to a file in smaller chunks may cause an 
inefficient read-modify-rewrite.) 
----------------------------------------------------------------

Probably, using STAT_ST_BLOCKSIZE is better way, same as 
smbd/trans2/get_allocation_size().

And, should make sure SPARSE attribute apply to regular file.

Finally, I think below code is better for Linux.
-------------------------------------------------------------------
#if defined (HAVE_STAT_ST_BLOCKS) && defined (STAT_ST_BLOCKSIZE)
    if (S_ISREG(sbuf->st_mode ) && sbuf->st_size > sbuf->st_blocks * 
STAT_ST_BLOCKSIZE ) {
        result |= FILE_ATTRIBUTE_SPARSE;
    }
#endif
-------------------------------------------------------------------