[Ocfs2-tools-devel] [PATCH 1/1] ocfs2-toos: Set hash seed when converting ocfs2 to support indexed-dirs

[Mark Fasheh]

Hi Tiger,

On Sat, Feb 12, 2011 at 05:42:30PM +0800, Tiger Yang wrote:
> This patch fix a issue when enable indexed-dirs with
> tunefs.ocfs2. We should set the hash seed in super block
> when we convert ocfs2 to support indexed-dirs.
> 
> Signed-off-by: Tiger Yang <tiger.yang at oracle.com>
> ---
>  include/ocfs2-kernel/ocfs2_fs.h     |    2 +-
>  tunefs.ocfs2/feature_indexed_dirs.c |    9 +++++++++
>  2 files changed, 10 insertions(+), 1 deletions(-)
> 
> diff --git a/include/ocfs2-kernel/ocfs2_fs.h b/include/ocfs2-kernel/ocfs2_fs.h
> index ffda634..e1fe24d 100644
> --- a/include/ocfs2-kernel/ocfs2_fs.h
> +++ b/include/ocfs2-kernel/ocfs2_fs.h
> @@ -610,7 +610,7 @@ struct ocfs2_super_block {
>  	__le16 s_reserved0;
>  	__le32 s_dx_seed[3];		/* seed[0-2] for dx dir hash.
>  					 * s_uuid_hash serves as seed[3]. */
> -/*C0*/  __le64 s_reserved2[15];		/* Fill out superblock */
> +/*C8*/  __le64 s_reserved2[15];		/* Fill out superblock */
>  /*140*/
>  
>  	/*
> diff --git a/tunefs.ocfs2/feature_indexed_dirs.c b/tunefs.ocfs2/feature_indexed_dirs.c
> index 7a918e7..5cdc86c 100644
> --- a/tunefs.ocfs2/feature_indexed_dirs.c
> +++ b/tunefs.ocfs2/feature_indexed_dirs.c
> @@ -117,6 +117,12 @@ static int enable_indexed_dirs(ocfs2_filesys *fs, int flags)
>  		goto out;
>  	}
>  
> +	/* set seed for indexed dir hash */
> +	srand48(time(NULL));
> +	super->s_dx_seed[0] = mrand48();
> +	super->s_dx_seed[1] = mrand48();
> +	super->s_dx_seed[2] = mrand48();
> +

We also want to be populating s_uuid_hash in the case that extended
attributes are not enabled.


>  	OCFS2_SET_INCOMPAT_FEATURE(super,
>  				   OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS);
>  
> @@ -302,6 +308,9 @@ static int disable_indexed_dirs(ocfs2_filesys *fs, int flags)
>  	 * fsck.ocfs2 will handle the orphan indexed trees. */
>  	OCFS2_CLEAR_INCOMPAT_FEATURE(super,
>  				     OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS);
> +
> +	super->s_dx_seed[0] = super->s_dx_seed[1] = super->s_dx_seed[2] = 0;

... and likewise, we should probably clear s_uuid_hash when
extended attributes are not enabled.
	--Mark

--
Mark Fasheh