From ab680bb739ca0e969148951c2e127f6683dcb933 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 6 Dec 2011 21:58:20 +0000 Subject: [PATCH] xfs: simplify xfs_qm_dqattach_grouphint No need to play games with the qlock now that the freelist lock nests inside it. Also clean up various outdated comments. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Ben Myers --- fs/xfs/xfs_qm.c | 64 +++++++++++++------------------------------------ 1 file changed, 16 insertions(+), 48 deletions(-) diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index 22360bb26af9..3c553454443c 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -650,11 +650,7 @@ xfs_qm_dqattach_one( /* * Given a udquot and gdquot, attach a ptr to the group dquot in the - * udquot as a hint for future lookups. The idea sounds simple, but the - * execution isn't, because the udquot might have a group dquot attached - * already and getting rid of that gets us into lock ordering constraints. - * The process is complicated more by the fact that the dquots may or may not - * be locked on entry. + * udquot as a hint for future lookups. */ STATIC void xfs_qm_dqattach_grouphint( @@ -665,45 +661,21 @@ xfs_qm_dqattach_grouphint( xfs_dqlock(udq); - if ((tmp = udq->q_gdquot)) { - if (tmp == gdq) { - xfs_dqunlock(udq); - return; - } + tmp = udq->q_gdquot; + if (tmp) { + if (tmp == gdq) + goto done; udq->q_gdquot = NULL; - /* - * We can't keep any dqlocks when calling dqrele, - * because the freelist lock comes before dqlocks. - */ - xfs_dqunlock(udq); - /* - * we took a hard reference once upon a time in dqget, - * so give it back when the udquot no longer points at it - * dqput() does the unlocking of the dquot. - */ xfs_qm_dqrele(tmp); - - xfs_dqlock(udq); - xfs_dqlock(gdq); - - } else { - ASSERT(XFS_DQ_IS_LOCKED(udq)); - xfs_dqlock(gdq); - } - - ASSERT(XFS_DQ_IS_LOCKED(udq)); - ASSERT(XFS_DQ_IS_LOCKED(gdq)); - /* - * Somebody could have attached a gdquot here, - * when we dropped the uqlock. If so, just do nothing. - */ - if (udq->q_gdquot == NULL) { - XFS_DQHOLD(gdq); - udq->q_gdquot = gdq; } + xfs_dqlock(gdq); + XFS_DQHOLD(gdq); xfs_dqunlock(gdq); + + udq->q_gdquot = gdq; +done: xfs_dqunlock(udq); } @@ -770,17 +742,13 @@ xfs_qm_dqattach_locked( ASSERT(ip->i_gdquot); /* - * We may or may not have the i_udquot locked at this point, - * but this check is OK since we don't depend on the i_gdquot to - * be accurate 100% all the time. It is just a hint, and this - * will succeed in general. + * We do not have i_udquot locked at this point, but this check + * is OK since we don't depend on the i_gdquot to be accurate + * 100% all the time. It is just a hint, and this will + * succeed in general. */ - if (ip->i_udquot->q_gdquot == ip->i_gdquot) - goto done; - /* - * Attach i_gdquot to the gdquot hint inside the i_udquot. - */ - xfs_qm_dqattach_grouphint(ip->i_udquot, ip->i_gdquot); + if (ip->i_udquot->q_gdquot != ip->i_gdquot) + xfs_qm_dqattach_grouphint(ip->i_udquot, ip->i_gdquot); } done: