From: Christoph Hellwig Date: Tue, 27 Mar 2012 14:34:46 +0000 (-0400) Subject: xfs: avoid taking the ilock unnessecarily in xfs_qm_dqattach X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b4d05e3019692fc5a8c573fbce60de2d48c5b7a1;p=linux-beck.git 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: Christoph Hellwig Reviewed-by: Mark Tinguely Reviewed-by: Dave Chinner Signed-off-by: Ben Myers --- diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index 55c6afedc879..18ba438386ab 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -483,6 +483,23 @@ done: 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 @@ -500,11 +517,7 @@ xfs_qm_dqattach_locked( uint nquotas = 0; int error = 0; - if (!XFS_IS_QUOTA_RUNNING(mp) || - !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) + if (!xfs_qm_need_dqattach(ip)) return 0; ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); @@ -575,6 +588,9 @@ xfs_qm_dqattach( { int error; + if (!xfs_qm_need_dqattach(ip)) + return 0; + xfs_ilock(ip, XFS_ILOCK_EXCL); error = xfs_qm_dqattach_locked(ip, flags); xfs_iunlock(ip, XFS_ILOCK_EXCL);