[Ocfs2-devel] [PATCH 1/2] Ocfs2: Add a new code 'OCFS2_INFO_FREEINODE' for o2info ioctl.

[Joel Becker <Joel.Becker@oracle.com>]

On Thu, Nov 04, 2010 at 04:10:50PM +0800, tristan wrote:
>     Yep, you're correct, other than the operation we read inode block, 
> the lookup
> of blkno/inode should also be treated differently according to coherency 
> flag, I
> guess following logic could help:
> 
> if (cluster_coherent) {
>     alloc_inode = ocfs2_get_system_file_inode();
>     ocfs2_inode_lock(alloc_inode, &bh);
> } else {
>     ocfs2_lookup_ino_from_name("global_bitmap", &blkno);
>     ocfs2_read_blocks(blkno, 1, &bh);
> }
> ...
> 
> Above logic guarantee the performance for none-coherency case.

	You got it.  But don't hardcode file names.  Use the sprintf
function for type+slot as in the top of _ocfs2_get_system_file_inode().
or write a lookup_ino_by_type.  Or something like that.

Joel

-- 

Life's Little Instruction Book #80

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Joel Becker
Senior Development Manager
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127