on Linux force convert 'zfs send -I' to a series of 'zfs send -i' as …

…a work-around for openzfs/zfs#16394

README.md

@@ -423,7 +423,7 @@ cat /tmp/manpage.md
     --no-privilege-elevation flag is for non-root users that have been
     granted corresponding ZFS permissions by administrators via 'zfs
     allow' delegation mechanism, like so: sudo zfs allow -u
-    $NON_ROOT_USER_NAME send,hold,bookmark $SRC_DATASET; sudo zfs
+    $NON_ROOT_USER_NAME send,bookmark $SRC_DATASET; sudo zfs
     allow -u $NON_ROOT_USER_NAME
     mount,create,receive,rollback,destroy,canmount,mountpoint,readonly,compression,encryption,keylocation,recordsize
     $DST_DATASET_OR_POOL; If you do not plan to use the --force flag

test/test_wbackup_zfs.py

@@ -193,7 +193,7 @@ def run_wbackup(self, *args, dry_run=None, no_create_bookmark=False, no_use_book
         if self.is_no_privilege_elevation():
             # test ZFS delegation in combination with --no-privilege-elevation flag
             args = args + ['--no-privilege-elevation']
-            src_permissions = 'send,hold'
+            src_permissions = 'send'
             if not is_solaris_zfs():
                 src_permissions += ',bookmark'
             optional_dst_permissions = ',canmount,mountpoint,readonly,compression,encryption,keylocation,recordsize'
@@ -1320,9 +1320,9 @@ def permute_snapshot_series(self, max_length=9):
     def validate_incremental_replication_steps(self, input_snapshots, expected_results):
         # src_dataset = "s@"
         src_dataset = ""
-        for is_bookmark_start in [False, True]:
+        for force_convert_I_to_i in [False, True]:
             steps = self.incremental_replication_steps1(
-                input_snapshots, src_dataset, is_bookmark_start=is_bookmark_start)
+                input_snapshots, src_dataset, force_convert_I_to_i=force_convert_I_to_i)
             # print(f"input_snapshots:" + ','.join(input_snapshots))
             # print("steps: " + ','.join([self.replication_step_to_str(step) for step in steps]))
             output_snapshots = [] if len(expected_results) == 0 else [expected_results[0]]
@@ -1346,13 +1346,13 @@ def apply_incremental_replication_steps(self, steps, input_snapshots):
                 output_snapshots.append(input_snapshots[end])
         return output_snapshots
 
-    def incremental_replication_steps1(self, input_snapshots, src_dataset, is_bookmark_start=False):
+    def incremental_replication_steps1(self, input_snapshots, src_dataset, force_convert_I_to_i=False):
         origin_src_snapshots_with_guids = []
-        has_snapshot = set()
+        has_snapshot = None if force_convert_I_to_i else set()
         guid = 1
         for i, snapshot in enumerate(input_snapshots):
             origin_src_snapshots_with_guids.append(f"{guid}\t{src_dataset}{snapshot}")
-            if i > 0 or not is_bookmark_start:
+            if has_snapshot is not None:
                 has_snapshot.add(guid)
             guid += 1
         return self.incremental_replication_steps2(origin_src_snapshots_with_guids, has_snapshot)

wbackup_zfs/wbackup_zfs.py

@@ -304,7 +304,7 @@ def argument_parser() -> argparse.ArgumentParser:
               "`<NON_ROOT_USER_NAME> ALL=NOPASSWD:/path/to/zfs`). "
               "Instead, the --no-privilege-elevation flag is for non-root users that have been granted corresponding "
               "ZFS permissions by administrators via 'zfs allow' delegation mechanism, like so: "
-              "sudo zfs allow -u $NON_ROOT_USER_NAME send,hold,bookmark $SRC_DATASET; "
+              "sudo zfs allow -u $NON_ROOT_USER_NAME send,bookmark $SRC_DATASET; "
               "sudo zfs allow -u $NON_ROOT_USER_NAME mount,create,receive,rollback,destroy,canmount,mountpoint,"
               "readonly,compression,encryption,keylocation,recordsize $DST_DATASET_OR_POOL; "
               "If you do not plan to use the --force flag or --delete-missing-snapshots or --delete-missing-dataset "
@@ -1029,6 +1029,10 @@ def incremental_replication_steps_wrapper(self, origin_src_snapshots_with_guids:
             guid, snapshot = line.split('\t', 1)
             guids.append(guid)
             input_snapshots.append(snapshot)
+        if not self.params.src_sudo and os.geteuid() != 0 and platform.system() == 'Linux':
+            # If using 'zfs allow' delegation mechanism on Linux, force convert 'zfs send -I' to a series of
+            # 'zfs send -i' as a workaround for zfs bug https://github.com/openzfs/zfs/issues/16394
+            has_snapshot = None
         return self.incremental_replication_steps(input_snapshots, guids, included_guids, has_snapshot)
 
     def incremental_replication_steps(self, src_snapshots: List[str], guids: List[str],
@@ -1044,10 +1048,10 @@ def incremental_replication_steps(self, src_snapshots: List[str], guids: List[st
         The has_snapshot param is necessary because 'zfs send' CLI with a bookmark as starting snapshot does not
         (yet) support including intermediate src_snapshots via -I flag. Thus, if the replication source is a bookmark
         we convert a -I step to one or more -i steps.
+        has_snapshot is None case is necessary as a work-around for https://github.com/openzfs/zfs/issues/16394
         """
         assert len(guids) == len(src_snapshots)
         assert len(included_guids) >= 0
-        assert len(has_snapshot) >= 0
         steps = []
         n = len(guids)
         i = 0
@@ -1080,7 +1084,7 @@ def incremental_replication_steps(self, src_snapshots: List[str], guids: List[st
                     if start != i:
                         step = ('-I', src_snapshots[start], src_snapshots[i])
                         # print(f"r2 {self.replication_step_to_str(step)}")
-                        if guids[start] in has_snapshot:
+                        if has_snapshot is not None and guids[start] in has_snapshot:
                             steps.append(step)
                         else:  # convert to -i steps
                             for j in range(start, i):
@@ -1092,7 +1096,7 @@ def incremental_replication_steps(self, src_snapshots: List[str], guids: List[st
                 if start != i:
                     step = ('-I', src_snapshots[start], src_snapshots[i])
                     # print(f"r3 {self.replication_step_to_str(step)}")
-                    if guids[start] in has_snapshot:
+                    if has_snapshot is not None and guids[start] in has_snapshot:
                         steps.append(step)
                     else:   # convert to -i steps
                         for j in range(start, i):