From: Andrew Deason <adeason@sinenomine.net>
Date: Fri, 25 Feb 2011 20:43:09 +0000 (-0600)
Subject: DAFS: Wait for exclusive ops in VFreeBitMapEntry_r
X-Git-Tag: openafs-devel-1_7_1~857
X-Git-Url: http://git.openafs.org/?p=openafs.git;a=commitdiff_plain;h=08ffe3e81d875b58ae5fe4c5733845d5132913a0;hp=a862d2df93fd4e8c8c7a0b8eebe9e59b75f54072

DAFS: Wait for exclusive ops in VFreeBitMapEntry_r

VAllocBitmapEntry_r puts the volume in an exclusive state and drops
VOL_LOCK when traversing the volume bitmap and updating the bitmap.
So, VFreeBitMapEntry_r must ensure the volume is not in an exclusive
state, to make sure that VAllocBitmapEntry_r is not updating the
bitmap at the same time. Do so, by waiting for the volume to come out
of exclusive state at the beginning of VFreeBitMapEntry_r.

Change-Id: I5fdd344e4d9d12451fd65a767fa5672c8be70a39
Reviewed-on: http://gerrit.openafs.org/4058
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
---

diff --git a/src/vol/vnode.c b/src/vol/vnode.c
index 42270c3..3c10baa 100644
--- a/src/vol/vnode.c
+++ b/src/vol/vnode.c
@@ -813,7 +813,7 @@ VAllocVnode_r(Error * ec, Volume * vp, VnodeType type)
 	    if (fdP)
 		FDH_CLOSE(fdP);
 	    VOL_LOCK;
-	    VFreeBitMapEntry_r(&tmp, &vp->vnodeIndex[class], bitNumber);
+	    VFreeBitMapEntry_r(&tmp, vp, &vp->vnodeIndex[class], bitNumber, 0 /*flags*/);
 	    VInvalidateVnode_r(vnp);
 	    VnUnlock(vnp, WRITE_LOCK);
 	    VnCancelReservation_r(vnp);
@@ -931,6 +931,12 @@ VnLoad(Error * ec, Volume * vp, Vnode * vnp,
 	    unsigned int bitNumber = vnodeIdToBitNumber(Vn_id(vnp));
 	    unsigned int offset = bitNumber >> 3;
 
+#ifdef AFS_DEMAND_ATTACH_FS
+	    /* Make sure the volume bitmap isn't getting updated while we are
+	     * checking it */
+	    VWaitExclusiveState_r(vp);
+#endif
+
 	    /* Test to see if vnode number is valid. */
 	    if ((offset >= index->bitmapSize)
 		|| ((*(index->bitmap + offset) & (1 << (bitNumber & 0x7)))
@@ -1380,8 +1386,9 @@ VPutVnode_r(Error * ec, Vnode * vnp)
 		if (vnp->delete && !*ec) {
 		    if (Vn_volume(vnp)->header->diskstuff.filecount-- < 1)
 			Vn_volume(vnp)->header->diskstuff.filecount = 0;
-		    VFreeBitMapEntry_r(ec, &vp->vnodeIndex[class],
-				       vnodeIdToBitNumber(Vn_id(vnp)));
+		    VFreeBitMapEntry_r(ec, vp, &vp->vnodeIndex[class],
+				       vnodeIdToBitNumber(Vn_id(vnp)),
+				       VOL_FREE_BITMAP_WAIT);
 		}
 	    }
 	    vcp->writes++;
diff --git a/src/vol/volume.c b/src/vol/volume.c
index 5b9f348..1217ec6 100644
--- a/src/vol/volume.c
+++ b/src/vol/volume.c
@@ -6311,32 +6311,50 @@ VAllocBitmapEntry(Error * ec, Volume * vp, struct vnodeIndex * index)
 }
 
 void
-VFreeBitMapEntry_r(Error * ec, struct vnodeIndex *index,
-		   unsigned bitNumber)
+VFreeBitMapEntry_r(Error * ec, Volume *vp, struct vnodeIndex *index,
+		   unsigned bitNumber, int flags)
 {
     unsigned int offset;
 
     *ec = 0;
+
+#ifdef AFS_DEMAND_ATTACH_FS
+    if (flags & VOL_FREE_BITMAP_WAIT) {
+	/* VAllocBitmapEntry_r allocs bitmap entries under an exclusive volume
+	 * state, so ensure we're not in an exclusive volume state when we update
+	 * the bitmap */
+	VCreateReservation_r(vp);
+	VWaitExclusiveState_r(vp);
+    }
+#endif
+
 #ifdef BITMAP_LATER
     if (!index->bitmap)
-	return;
+	goto done;
 #endif /* BITMAP_LATER */
+
     offset = bitNumber >> 3;
     if (offset >= index->bitmapSize) {
 	*ec = VNOVNODE;
-	return;
+	goto done;
     }
     if (offset < index->bitmapOffset)
 	index->bitmapOffset = offset & ~3;	/* Truncate to nearest bit32 */
     *(index->bitmap + offset) &= ~(1 << (bitNumber & 0x7));
+
+ done:
+#ifdef AFS_DEMAND_ATTACH_FS
+    VCancelReservation_r(vp);
+#endif
+    return; /* make the compiler happy for non-DAFS */
 }
 
 void
-VFreeBitMapEntry(Error * ec, struct vnodeIndex *index,
+VFreeBitMapEntry(Error * ec, Volume *vp, struct vnodeIndex *index,
 		 unsigned bitNumber)
 {
     VOL_LOCK;
-    VFreeBitMapEntry_r(ec, index, bitNumber);
+    VFreeBitMapEntry_r(ec, vp, index, bitNumber, VOL_FREE_BITMAP_WAIT);
     VOL_UNLOCK;
 }
 
diff --git a/src/vol/volume.h b/src/vol/volume.h
index 598283e..e4dad3c 100644
--- a/src/vol/volume.h
+++ b/src/vol/volume.h
@@ -822,10 +822,10 @@ extern int VAllocBitmapEntry(Error * ec, Volume * vp,
 			     struct vnodeIndex *index);
 extern int VAllocBitmapEntry_r(Error * ec, Volume * vp,
 			       struct vnodeIndex *index, int flags);
-extern void VFreeBitMapEntry(Error * ec, struct vnodeIndex *index,
+extern void VFreeBitMapEntry(Error * ec, Volume *vp, struct vnodeIndex *index,
 			     unsigned bitNumber);
-extern void VFreeBitMapEntry_r(Error * ec, struct vnodeIndex *index,
-			       unsigned bitNumber);
+extern void VFreeBitMapEntry_r(Error * ec, Volume *vp, struct vnodeIndex *index,
+			       unsigned bitNumber, int flags);
 extern int VolumeNumber(char *name);
 extern char *VolumeExternalName(VolumeId volumeId);
 extern int VolumeExternalName_r(VolumeId volumeId, char *name, size_t len);
@@ -1023,6 +1023,9 @@ extern int VWalkVolumeHeaders(struct DiskPartition64 *dp, const char *partpath,
 /* VAllocBitmapEntry_r flags */
 #define VOL_ALLOC_BITMAP_WAIT    0x1  /* for demand attach, wait for other exclusive ops to end */
 
+/* VFreeBitMapEntry_r flags */
+#define VOL_FREE_BITMAP_WAIT     0x1  /* for demand attach, wait for other exclusive ops to end */
+
 /* VRequestSalvage_r flags */
 #define VOL_SALVAGE_INVALIDATE_HEADER 0x1 /* for demand attach fs, invalidate volume header cache */
 #define VOL_SALVAGE_NO_OFFLINE        0x2 /* we do not need to wait to offline the volume; it has