[PATCH 1/5] xfs: avoid taking the ilock unnessecarily in xfs_qm_dqattach

[Dave Chinner]

On Mon, Mar 26, 2012 at 05:14:22PM -0400, Christoph Hellwig wrote:
> Check if we actually need to attach a dquot before taking the ilock in
> xfs_qm_dqattach.  This avoid superflous lock roundtrips for the common cases
> of quota support compiled in but not activated on a filesystem and an
> inode that already has the dquots attached.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Looks good. One minor thing:

> +static inline bool
> +xfs_qm_need_dqattach(
> +	struct xfs_inode	*ip)
> +{
> +	struct xfs_mount	*mp = ip->i_mount;
> +
> +	if (!XFS_IS_QUOTA_RUNNING(mp))
> +		return false;
> +	if (!XFS_IS_QUOTA_ON(mp))
> +		return false;
> +	if (!XFS_NOT_DQATTACHED(mp, ip))
> +		return false;
> +	if (ip->i_ino == mp->m_sb.sb_uquotino ||
> +	    ip->i_ino == mp->m_sb.sb_gquotino)
> +		return false;
> +	return true;
> +}

That's probably a little large for an inline function. Let the
compiler decide whether to inline it or not. In most cases, it will
inline it because it is a static function....

Otherwise,

Reviewed-by: Dave Chinner <dchinner at redhat.com>
-- 
Dave Chinner
david at fromorbit.com