filesystems: use g_vfs_close_unlocked(9)

As result, we lock the devvp vnode around calls to VOP_FSYNC() on
unmount. For instance, the vn_fsync_buf() implementation of fsync()
needs exclusive lock on the vnode to guarantee that all dirty buffers
are indeed synced.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D59932

sys/fs/cd9660/cd9660_vfsops.c

@@ -506,11 +506,8 @@ out:
 		brelse(pribp);
 	if (supbp != NULL)
 		brelse(supbp);
-	if (cp != NULL) {
-		g_topology_lock();
-		g_vfs_close(cp);
-		g_topology_unlock();
-	}
+	if (cp != NULL)
+		g_vfs_close_unlocked(cp);
 	if (isomp) {
 		free(isomp, M_ISOFSMNT);
 		mp->mnt_data = NULL;
@@ -541,9 +538,7 @@ cd9660_unmount(struct mount *mp, int mntflags)
 		if (isomp->im_l2d)
 			cd9660_iconv->close(isomp->im_l2d);
 	}
-	g_topology_lock();
-	g_vfs_close(isomp->im_cp);
-	g_topology_unlock();
+	g_vfs_close_unlocked(isomp->im_cp);
 	vrele(isomp->im_devvp);
 	dev_rel(isomp->im_dev);
 	free(isomp, M_ISOFSMNT);

sys/fs/ext2fs/ext2_vfsops.c

@@ -837,7 +837,6 @@ ext2_mountfs(struct vnode *devvp, struct mount *mp)
 	struct ext2fs *es;
 	struct cdev *dev = devvp->v_rdev;
 	struct g_consumer *cp;
-	struct bufobj *bo;
 	struct csum *sump;
 	int error;
 	int ronly;
@@ -870,9 +869,6 @@ ext2_mountfs(struct vnode *devvp, struct mount *mp)
 		goto out;
 	}
 
-	bo = &devvp->v_bufobj;
-	bo->bo_private = cp;
-	bo->bo_ops = g_vfs_bufops;
 	if (devvp->v_rdev->si_iosize_max != 0)
 		mp->mnt_iosize_max = devvp->v_rdev->si_iosize_max;
 	if (mp->mnt_iosize_max > maxphys)
@@ -983,11 +979,8 @@ ext2_mountfs(struct vnode *devvp, struct mount *mp)
 out:
 	if (bp)
 		brelse(bp);
-	if (cp != NULL) {
-		g_topology_lock();
-		g_vfs_close(cp);
-		g_topology_unlock();
-	}
+	if (cp != NULL)
+		g_vfs_close_unlocked(cp);
 	if (ump) {
 		mtx_destroy(EXT2_MTX(ump));
 		free(ump->um_e2fs->e2fs_gd, M_EXT2MNT);
@@ -1029,9 +1022,7 @@ ext2_unmount(struct mount *mp, int mntflags)
 		ext2_sbupdate(ump, MNT_WAIT);
 	}
 
-	g_topology_lock();
-	g_vfs_close(ump->um_cp);
-	g_topology_unlock();
+	g_vfs_close_unlocked(ump->um_cp);
 	vrele(ump->um_devvp);
 	sump = fs->e2fs_clustersum;
 	for (i = 0; i < fs->e2fs_gcount; i++, sump++)

sys/fs/msdosfs/msdosfs_vfsops.c

@@ -863,11 +863,8 @@ mountmsdosfs(struct vnode *odevvp, struct mount *mp)
 error_exit:
 	if (bp != NULL)
 		brelse(bp);
-	if (cp != NULL) {
-		g_topology_lock();
-		g_vfs_close(cp);
-		g_topology_unlock();
-	}
+	if (cp != NULL)
+		g_vfs_close_unlocked(cp);
 	if (pmp != NULL) {
 		lockdestroy(&pmp->pm_fatlock);
 		free(pmp->pm_inusemap, M_MSDOSFSFAT);

sys/fs/udf/udf_vfsops.c

@@ -496,11 +496,8 @@ bail:
 		free(udfmp, M_UDFMOUNT);
 	if (bp != NULL)
 		brelse(bp);
-	if (cp != NULL) {
-		g_topology_lock();
-		g_vfs_close(cp);
-		g_topology_unlock();
-	}
+	if (cp != NULL)
+		g_vfs_close_unlocked(cp);
 	dev_rel(dev);
 	return error;
 };
@@ -528,9 +525,7 @@ udf_unmount(struct mount *mp, int mntflags)
 #endif
 	}
 
-	g_topology_lock();
-	g_vfs_close(udfmp->im_cp);
-	g_topology_unlock();
+	g_vfs_close_unlocked(udfmp->im_cp);
 	vrele(udfmp->im_devvp);
 	dev_rel(udfmp->im_dev);
 

sys/ufs/ffs/ffs_vfsops.c

@@ -1202,11 +1202,8 @@ out:
 		free(fs->fs_si, M_UFSMNT);
 		free(fs, M_UFSMNT);
 	}
-	if (cp != NULL) {
-		g_topology_lock();
-		g_vfs_close(cp);
-		g_topology_unlock();
-	}
+	if (cp != NULL)
+		g_vfs_close_unlocked(cp);
 	if (ump != NULL) {
 		mtx_destroy(UFS_MTX(ump));
 		if (mp->mnt_gjprovider != NULL) {