svn commit: r294200 - head/sys/fs/nandfs

[Ravi Pokala]

Author: rpokala
Date: Sun Jan 17 01:04:20 2016
New Revision: 294200
URL: https://svnweb.freebsd.org/changeset/base/294200

Log:
  [PR 206224] bv_cnt is sometimes examined without holding the bufobj lock
  
  Add locking around access to bv_cnt which is currently being done unlocked
  
  PR:		206224
  Reviewed by:	imp
  Approved by:	jhb
  MFC after:	1 week
  Sponsored by:	Panasas, Inc.
  Differential Revision:	https://reviews.freebsd.org/D4931

Modified:
  head/sys/fs/nandfs/nandfs_segment.c

Modified: head/sys/fs/nandfs/nandfs_segment.c
==============================================================================
--- head/sys/fs/nandfs/nandfs_segment.c	Sun Jan 17 00:52:28 2016	(r294199)
+++ head/sys/fs/nandfs/nandfs_segment.c	Sun Jan 17 01:04:20 2016	(r294200)
@@ -479,6 +479,7 @@ nandfs_iterate_dirty_vnodes(struct mount
 	struct nandfs_node *nandfs_node;
 	struct vnode *vp, *mvp;
 	struct thread *td;
+	struct bufobj *bo;
 	int error, update;
 
 	td = curthread;
@@ -499,17 +500,21 @@ nandfs_iterate_dirty_vnodes(struct mount
 			update = 1;
 		}
 
+		bo = &vp->v_bufobj;
+		BO_LOCK(bo);
 		if (vp->v_bufobj.bo_dirty.bv_cnt) {
 			error = nandfs_iterate_dirty_buf(vp, seginfo, 0);
 			if (error) {
 				nandfs_error("%s: cannot iterate vnode:%p "
 				    "err:%d\n", __func__, vp, error);
 				vput(vp);
+				BO_UNLOCK(bo);
 				return (error);
 			}
 			update = 1;
 		} else
 			vput(vp);
+		BO_UNLOCK(bo);
 
 		if (update)
 			nandfs_node_update(nandfs_node);