xfs: fix dquot isolation hang

From: Dave Chinner <[email protected]>

The new LRU list isolation code in xfs_qm_dquot_isolate() isn't completely up to date. Firstly, it needs conversion to return enum lru_status values, not raw numbers. Secondly - most importantly - it fails to unlock the dquot and relock the LRU in the LRU_RETRY path. This leads to deadlocks in xfstests generic/232. Fix them.

Signed-off-by Dave Chinner <[email protected]>

---
 fs/xfs/xfs_qm.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

fs/xfs/xfs_qm.c +6 -4

index 46743cf..a10a720 100644
@@ -659,7 +659,7 @@ xfs_qm_dquot_isolate(
 		trace_xfs_dqreclaim_want(dqp);
 		list_del_init(&dqp->q_lru);
 		XFS_STATS_DEC(xs_qm_dquot_unused);
-		return 0;
+		return LRU_REMOVED;
 	}
 
 	/*

@@ -705,17 +705,19 @@ xfs_qm_dquot_isolate(
 	XFS_STATS_DEC(xs_qm_dquot_unused);
 	trace_xfs_dqreclaim_done(dqp);
 	XFS_STATS_INC(xs_qm_dqreclaims);
-	return 0;
+	return LRU_REMOVED;
 
 out_miss_busy:
 	trace_xfs_dqreclaim_busy(dqp);
 	XFS_STATS_INC(xs_qm_dqreclaim_misses);
-	return 2;
+	return LRU_SKIP;
 
 out_unlock_dirty:
 	trace_xfs_dqreclaim_busy(dqp);
 	XFS_STATS_INC(xs_qm_dqreclaim_misses);
-	return 3;
+	xfs_dqunlock(dqp);
+	spin_lock(lru_lock);
+	return LRU_RETRY;
 }
 
 static unsigned long

Signature · 1 line

1.8.3.2