Relax restriction on zfs_ioc_next_obj() iteration

Per the documentation for dnode_next_offset in dnode.c, the "txg"
parameter specifies a lower bound on which transaction the dnode can
be found in. We are interested in all dnodes that are removed between
the first and last transaction in the snapshot. It doesn't need to be
created in that snapshot to correspond to a removed file.

In fact, the behavior of zfs diff in the test case exactly matches
this: the transaction that created the data that was deleted in snapshot
"2" was produced before, in snapshot "1", definitely predating the first
transaction in snapshot "2".

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <Tim Chase <tim@onlight.com>
Closes #2081

diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 7a890cf3f6dc96bad20a4f3ab885dc047a7e7c6d..4c0060b67bb7d9d65ba3ffc9f0382d3411a25af8 100644 (file)
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -4724,8 +4724,7 @@ zfs_ioc_next_obj(zfs_cmd_t *zc)
        if (error != 0)
                return (error);
 
-       error = dmu_object_next(os, &zc->zc_obj, B_FALSE,
-           dsl_dataset_phys(os->os_dsl_dataset)->ds_prev_snap_txg);
+       error = dmu_object_next(os, &zc->zc_obj, B_FALSE, 0);
 
        dmu_objset_rele(os, FTAG);
        return (error);