[lustre-devel] [PATCH 24/30] lustre: llite: rcu-walk check should not depend on statahead

[NeilBrown]

On Mon, Sep 17 2018, James Simmons wrote:

> From: Steve Guminski <stephenx.guminski at intel.com>
>
> Moves the check for the LOOKUP_RCU flag, so that it does not depend
> on the statahead setting.  The caller is now informed if rcu-walk
> was requested but the filesystem does not support it, regardless
> of whether statahead is enabled or disabled.

Nope, this is wrong.

The filesystem only returns -ECHILD if it couldn't complete the request
because it would have to block.
If statahead is disabled, then it can complete the request immediately,
doesn't need to block, and so doesn't need to return -ECHILD.

Patch deleted.

Thanks,
NeilBrown

>
> Signed-off-by: Steve Guminski <stephenx.guminski at intel.com>
> WC-bug-id: https://jira.whamcloud.com/browse/LU-8891
> Reviewed-on: https://review.whamcloud.com/24195
> Reviewed-by: John L. Hammond <jhammond at whamcloud.com>
> Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
> Reviewed-by: Oleg Drokin <green at whamcloud.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>  drivers/staging/lustre/lustre/llite/dcache.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/llite/dcache.c b/drivers/staging/lustre/lustre/llite/dcache.c
> index 11b82c63..ee1ba16 100644
> --- a/drivers/staging/lustre/lustre/llite/dcache.c
> +++ b/drivers/staging/lustre/lustre/llite/dcache.c
> @@ -270,13 +270,12 @@ static int ll_revalidate_dentry(struct dentry *dentry,
>  	if (lookup_flags & LOOKUP_REVAL)
>  		return 0;
>  
> -	if (!dentry_may_statahead(dir, dentry))
> -		return 1;
> -
>  	if (lookup_flags & LOOKUP_RCU)
>  		return -ECHILD;
>  
> -	ll_statahead(dir, &dentry, !d_inode(dentry));
> +	if (dentry_may_statahead(dir, dentry))
> +		ll_statahead(dir, &dentry, !d_inode(dentry));
> +
>  	return 1;
>  }
>  
> -- 
> 1.8.3.1
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