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@xxxxxx>
---
fs/xfs/xfs_qm.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)
Index: xfs/fs/xfs/xfs_qm.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.c 2012-03-26 21:11:12.000000000 +0200
+++ xfs/fs/xfs/xfs_qm.c 2012-03-27 08:04:51.765661301 +0200
@@ -476,6 +476,23 @@ 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
@@ -493,11 +510,7 @@ 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));
@@ -568,6 +581,9 @@ 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);
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