changes in fs.h and fsfilter.h

changes in fs.h and fsfilter.h

[Harsha Srinath]

I am trying to port a ext3 cow utility from 2.4 to 2.6. I have a
couple of questions that I figured is too ext3 specific for the
kernelnewbies list and am sincerely hoping I can find some help here.

1. In the the 2.4 ../include/linux/fs.h file, there is a union in the
VFS inode struct like :-
struct inode {
         struct list_head        i_hash;
         struct list_head        i_list;
         struct list_head        i_dentry;
         ........
         union {
                 struct minix_inode_info         minix_i;
                 struct ext2_inode_info          ext2_i;
                 struct ext3_inode_info          ext3_i;
         .......
                    }u;

Can anyone tell me where this union info is present in 2.6.10 ? I
grep'ed in the ..../include/linux/ directory but could not find the
union in any VFS files. (I want the VFS to know my changed ext3 inode
info that I call "struct extcow3_inode_info          extcow3_i".)

I guess the same answer would hold good for :-
struct super_block {
         struct list_head          s_list;         /* Keep this first */
         kdev_t                         s_dev;
         unsigned long           s_blocksize;
         unsigned char           s_blocksize_bits;
         .........
        union {
                 struct minix_sb_info    minix_sb;
                 struct ext2_sb_info     ext2_sb;
                 struct ext3_sb_info     ext3_sb;
        ...............
             }u;

2. I am unable to find the following #defines :-
#define FILTER_FS_TYPES 6
#define FILTER_FS_EXT2 0
#define FILTER_FS_EXT3 1
....................
that were earlier in ../include/linux/fsfilter.h in the 2.4 kernel.

Can anyone please tell me where this info is now? Again I tried
grep'ing into the files but could not find any file with that
information. I am a newbie and am not very sure what this info is too.
Can anyone shed some light please?

Thanks!
Harsha Srinath

Re: changes in fs.h

[Bryan Henderson]

>In the the 2.4 ../include/linux/fs.h file, there is a union in the
>VFS inode struct like :-
>...
>Can anyone tell me where this union info is present in 2.6.10 ? I
>grep'ed in the ..../include/linux/ directory but could not find the
>union in any VFS files.

The best way to solve a problem like this is to look at the code that used 
to use the missing structure, and see what it's using now.  In this case, 
though, I don't know why grepping for ext3_inode_info wouldn't work as 
well, and I can't think of what else you would grep for.

The information, for ext3 in particular, moved to 
include/linux/ext3_fs_i.h.

>I guess the same answer would hold good for :- [struct superblock]

Yes, those same two techniques lead you to include/linux/ext3_fs_sb.h.

--
Bryan Henderson                          IBM Almaden Research Center
San Jose CA                              Filesystems

Re: changes in fs.h and fsfilter.h

[Martin Jambor]

Hi,

On 5/6/05, Harsha Srinath <harsha@usc.edu> wrote:
> 1. In the the 2.4 ../include/linux/fs.h file, there is a union in the
> VFS inode struct like :-
> struct inode {
>          struct list_head        i_hash;
>          struct list_head        i_list;
>          struct list_head        i_dentry;
>          ........
>          union {
>                  struct minix_inode_info         minix_i;
>                  struct ext2_inode_info          ext2_i;
>                  struct ext3_inode_info          ext3_i;
>          .......
>                     }u;
> 
> Can anyone tell me where this union info is present in 2.6.10 ? I

I know nothing about 2.4 but the way you get an inode_info from an
inode in ext2 (and similarly in minix and I suspect in ext3 too) in
2.6 is by calling EXT2_I inline function defined in fs/ext2.h.

HTH

Martin Jambor