Attachment 170172 Details for Bug 207464 – proposed patch for testing

[patch] proposed patch for testing

zfsctl-snapshot-refcount.patch (text/plain), 2.66 KB, created by Andriy Gapon on 2016-05-10 09:37:06 UTC

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Creator: Andriy Gapon

Created: 2016-05-10 09:37:06 UTC

Size: 2.66 KB

patch

obsolete

>zfsctl: fix several problems with reference counts
>
>* Remove excessive references on a snapshot vnode.
>  zfsctl_snapdir_lookup() called VN_HOLD() on a vnode returned from
>  zfsctl_snapshot_mknode() and the latter also had a call to VN_HOLD()
>  on the same vnode.
>  On top of that gfs_dir_create() already returns the vnode with the
>  use count of 1 (set in getnewvnode).
>
>* mount_snapshot() should keep a reference on a covered snapshot vnode.
>  That reference is owned by the mountpoint (mounted snapshot filesystem).
>
>* Remove cryptic manipulations of a covered vnode in zfs_umount().
>  FreeBSD dounmount() already does the right thing and releases the covered
>  vnode.
>
>diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
>index 3ac811a9be583..f4130e1576551 100644
>--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
>+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
>@@ -1113,7 +1113,6 @@ zfsctl_snapdir_lookup(ap)
> 	sep->se_name = kmem_alloc(strlen(nm) + 1, KM_SLEEP);
> 	(void) strcpy(sep->se_name, nm);
> 	*vpp = sep->se_root = zfsctl_snapshot_mknode(dvp, dmu_objset_id(snap));
>-	VN_HOLD(*vpp);
> 	avl_insert(&sdp->sd_snaps, sep, where);
> 
> 	dmu_objset_rele(snap, FTAG);
>@@ -1490,7 +1489,6 @@ zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset)
> 
> 	vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp, pvp->v_vfsp,
> 	    &zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL);
>-	VN_HOLD(vp);
> 	zcp = vp->v_data;
> 	zcp->zc_id = objset;
> 	VOP_UNLOCK(vp, 0);
>diff --git a/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c b/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c
>index a2532f80222ec..a2ce66a207f96 100644
>--- a/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c
>+++ b/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c
>@@ -228,7 +228,7 @@ mount_snapshot(kthread_t *td, vnode_t **vpp, const char *fstype, char *fspath,
> 	vfs_event_signal(NULL, VQ_MOUNT, 0);
> 	if (VFS_ROOT(mp, LK_EXCLUSIVE, &mvp))
> 		panic("mount: lost mount");
>-	vput(vp);
>+	VOP_UNLOCK(vp, 0);
> 	vfs_unbusy(mp);
> 	*vpp = mvp;
> 	return (0);
>diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
>index 932b61a31ee9e..42629621ab6cd 100644
>--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
>+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
>@@ -2005,12 +2005,6 @@ zfs_umount(vfs_t *vfsp, int fflag)
> 	 */
> 	if (zfsvfs->z_ctldir != NULL)
> 		zfsctl_destroy(zfsvfs);
>-	if (zfsvfs->z_issnap) {
>-		vnode_t *svp = vfsp->mnt_vnodecovered;
>-
>-		if (svp->v_count >= 2)
>-			VN_RELE(svp);
>-	}
> 	zfs_freevfs(vfsp);
> 
> 	return (0);

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Attachments on bug 207464: 169495 | 170024 | 170172 | 170343