- Synchronize access to a vm page's valid field using the containing

   vm object's lock.

1 files changed, 10 insertions, 4 deletions

diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index d46ae86..11964ac 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -373,6 +373,7 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
 	bp->b_offset = tbp->b_offset;
 	KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset"));
 	pbgetvp(vp, bp);
+	bp->b_object = tbp->b_object;
 
 	TAILQ_INIT(&bp->b_cluster.cluster_head);
 
@@ -416,10 +417,14 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
 			 * take part in the cluster.  If it is partially valid
 			 * then we stop.
 			 */
+			VM_OBJECT_LOCK(tbp->b_object);
 			for (j = 0;j < tbp->b_npages; j++) {
+				VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object,
+				    MA_OWNED);
 				if (tbp->b_pages[j]->valid)
 					break;
 			}
+			VM_OBJECT_UNLOCK(tbp->b_object);
 			if (j != tbp->b_npages) {
 				bqrelse(tbp);
 				break;
@@ -454,8 +459,7 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
 		BUF_KERNPROC(tbp);
 		TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
 			tbp, b_cluster.cluster_entry);
-		if (tbp->b_object != NULL)
-			VM_OBJECT_LOCK(tbp->b_object);
+		VM_OBJECT_LOCK(tbp->b_object);
 		vm_page_lock_queues();
 		for (j = 0; j < tbp->b_npages; j += 1) {
 			vm_page_t m;
@@ -471,8 +475,7 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
 				tbp->b_pages[j] = bogus_page;
 		}
 		vm_page_unlock_queues();
-		if (tbp->b_object != NULL)
-			VM_OBJECT_UNLOCK(tbp->b_object);
+		VM_OBJECT_UNLOCK(tbp->b_object);
 		/*
 		 * XXX shouldn't this be += size for both, like in
 		 * cluster_wbuild()?
@@ -493,12 +496,15 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
 	 * Fully valid pages in the cluster are already good and do not need
 	 * to be re-read from disk.  Replace the page with bogus_page
 	 */
+	VM_OBJECT_LOCK(bp->b_object);
 	for (j = 0; j < bp->b_npages; j++) {
+		VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED);
 		if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) ==
 		    VM_PAGE_BITS_ALL) {
 			bp->b_pages[j] = bogus_page;
 		}
 	}
+	VM_OBJECT_UNLOCK(bp->b_object);
 	if (bp->b_bufsize > bp->b_kvasize)
 		panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
 		    bp->b_bufsize, bp->b_kvasize);