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Commit b4d05e30 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Ben Myers
Browse files

xfs: avoid taking the ilock unnessecarily in xfs_qm_dqattach 



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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMark Tinguely <tinguely@sgi.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 8a00ebe4

fs/xfs/xfs_qm.c

+21 −5
Original line number Original line Diff line number Diff line
@@ -483,6 +483,23 @@ done: 
	xfs_dqunlock(udq);

	xfs_dqunlock(udq);

}

}





static 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;

}





/*

/*

 * Given a locked inode, attach dquot(s) to it, taking U/G/P-QUOTAON

 * Given a locked inode, attach dquot(s) to it, taking U/G/P-QUOTAON
@@ -500,11 +517,7 @@ xfs_qm_dqattach_locked( 
	uint		nquotas = 0;

	uint		nquotas = 0;

	int		error = 0;

	int		error = 0;





	if (!XFS_IS_QUOTA_RUNNING(mp) ||

	if (!xfs_qm_need_dqattach(ip))

	    !XFS_IS_QUOTA_ON(mp) ||

	    !XFS_NOT_DQATTACHED(mp, ip) ||

	    ip->i_ino == mp->m_sb.sb_uquotino ||

	    ip->i_ino == mp->m_sb.sb_gquotino)

		return 0;

		return 0;





	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
@@ -575,6 +588,9 @@ xfs_qm_dqattach( 
{

{

	int			error;

	int			error;





	if (!xfs_qm_need_dqattach(ip))

		return 0;



	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	error = xfs_qm_dqattach_locked(ip, flags);

	error = xfs_qm_dqattach_locked(ip, flags);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);