DAFS: DFlushVolume outside of vol glock

DFlushVolume may traverse a long list of directory objects, and can
even hit the disk, so we should drop the glock for it. This should be
safe in DAFS, since we already transition the volume to an exclusive
state before doing this, and DFlushVolume only deals with structures
internal to the directory package and maintains its own locking.

Reviewed-on: http://gerrit.openafs.org/4242
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit a18175f479437f3a4fe68460538927630070cd13)

Change-Id: I355c53c6f224c5471da70827f30511986abeac27
Reviewed-on: http://gerrit.openafs.org/5767
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>

diff --git a/src/vol/volume.c b/src/vol/volume.c
index b10acdd5192ad34f2f51af5a2c18d4f1c13ba37b..72aab74c9233d718efecb5b85e68a05328b4aedf 100644 (file)
--- a/src/vol/volume.c
+++ b/src/vol/volume.c
@@ -4268,15 +4268,17 @@ VCloseVolumeHandles_r(Volume * vp)
     VolState state_save;
 
     state_save = VChangeState_r(vp, VOL_STATE_OFFLINING);
+
+    VOL_UNLOCK;
 #endif
 
-    /* demand attach fs
-     *
-     * XXX need to investigate whether we can perform
-     * DFlushVolume outside of vol_glock_mutex...
-     *
-     * VCloseVnodeFiles_r drops the glock internally */
     DFlushVolume(vp->hashid);
+
+#ifdef AFS_DEMAND_ATTACH_FS
+    VOL_LOCK;
+#endif
+
+    /* DAFS: VCloseVnodeFiles_r drops the glock internally */
     VCloseVnodeFiles_r(vp);
 
 #ifdef AFS_DEMAND_ATTACH_FS
@@ -4320,13 +4322,17 @@ VReleaseVolumeHandles_r(Volume * vp)
     VolState state_save;
 
     state_save = VChangeState_r(vp, VOL_STATE_DETACHING);
+
+    VOL_UNLOCK;
 #endif
 
-    /* XXX need to investigate whether we can perform
-     * DFlushVolume outside of vol_glock_mutex... */
     DFlushVolume(vp->hashid);
 
-    VReleaseVnodeFiles_r(vp); /* releases the glock internally */
+#ifdef AFS_DEMAND_ATTACH_FS
+    VOL_LOCK;
+#endif
+
+    VReleaseVnodeFiles_r(vp); /* DAFS: releases the glock internally */
 
 #ifdef AFS_DEMAND_ATTACH_FS
     VOL_UNLOCK;