feat: TrueNAS 26 support; enumerate datasets and snapshots from ZFS, not middleware
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TrueNAS 26 deletes plugins/zfs_/ outright, taking the private zfs.dataset.query,
zfs.snapshot.query and zfs.snapshot.delete with it. All three were on the nested
module's critical path, so nested snapshots were BROKEN on 26.

Snapshot deletion now resolves its namespace at runtime: pool.snapshot on 25.10
and 26, zfs.snapshot on 24.10 and 25.04. No single namespace spans every supported
release. tools/compat.py checks the same list the runtime uses, so what CI verifies
and what runs cannot drift apart.

Enumeration does NOT move to pool.dataset.query / pool.snapshot.query, and that is
the point of this commit. Those methods exist, are documented, and are covered by
iX's deprecation policy — and they are not like-for-like replacements. They apply a
visibility policy that hides ix-apps/*, .system/* and .ix-virt/*: 84 of 270 datasets
on a real pool, including live application data. Staging from that view omits them
silently, and plan_staging never sees them, so they do not even reach the skipped
list. The snapshot query hides the same datasets' snapshots, so the sweep orphans one
per hidden dataset on every run.

So: read the truth from ZFS, make changes through middleware. zfs list cannot be
filtered by policy and behaves identically on every release. A failing zfs list raises
rather than returning an empty list — "no datasets" and "the command broke" must never
look the same.

No shipped release is affected: v0.6.1 and earlier use the private zfs.dataset.query,
which returns all 270 datasets. The bug existed only in this port.

Verified on a real TrueNAS 26.0.0-BETA.1 install: 274-snapshot recursive backup of a
292-dataset pool, zero orphaned snapshots, zero leaked mounts, and a byte-identical
restore of a four-level-deep child dataset that pool.dataset.query hides.
This commit is contained in:
2026-07-13 22:43:20 +00:00
parent 7cc0826c2c
commit 605231b39f
8 changed files with 664 additions and 120 deletions
+146 -17
View File
@@ -204,18 +204,52 @@ class FakeMiddleware:
truecloud_nested.py. TrueNAS <= 25.10 reaches it through
`await middleware.run_in_thread(...)` and TrueNAS 26 calls it directly, but the
logic below the boundary is the same code either way, so it is tested once.
`snapshot_ns` picks which middleware GENERATION this is, because they do not
agree on what the snapshot service is called:
pool.snapshot 25.10 and 26 (26 has ONLY this -- plugins/zfs_/ is gone)
zfs.snapshot 24.10 and 25.04 (pool.snapshot does not exist yet)
A method in the namespace this box does NOT have raises, exactly as middleware
does ("Method does not exist"). That is what makes the runtime picker testable:
a module that guessed wrong would blow up here instead of silently orphaning
snapshots on somebody's NAS.
"""
def __init__(self, snapshots=None):
def __init__(self, snapshots=None, snapshot_ns="pool.snapshot"):
self.snapshots = list(snapshots or [])
self.calls = []
self.logger = None
self.snapshot_ns = snapshot_ns
def get_service(self, name):
if name != self.snapshot_ns:
raise KeyError(name) # middleware raises KeyError for an unknown ns
return object()
def list_snapshots(self, dataset):
"""Stands in for `zfs list -t snapshot -r <dataset>`.
Enumeration comes from ZFS now, NOT from middleware -- middleware's query
hides internal datasets, and a sweep that cannot see a snapshot can never
collect it. Passed in as `list_snapshots=` so the seam is explicit.
"""
return [
n for n in self.snapshots
if n.split("@")[0] == dataset or n.startswith(dataset + "/")
]
def call_sync(self, method, *args):
self.calls.append((method, args))
if method == "zfs.snapshot.query":
namespace, _, op = method.rpartition(".")
if namespace != self.snapshot_ns:
raise RuntimeError("Method does not exist")
if op == "query":
return [{"name": n} for n in self.snapshots]
if method == "zfs.snapshot.delete":
if op == "delete":
name = args[0]
opts = args[1] if len(args) > 1 else {}
if name not in self.snapshots:
@@ -265,44 +299,44 @@ class TestDeleteSnapshotTree:
mw = FakeMiddleware([
"Tap@snap", "Tap/apps@snap", "Tap/apps/lidarr@snap", "Tap@keepme",
])
delete_snapshot_tree(mw, "Tap@snap")
delete_snapshot_tree(mw, "Tap@snap", list_snapshots=mw.list_snapshots)
assert mw.snapshots == ["Tap@keepme"]
def test_is_idempotent_when_stock_already_removed_the_parent(self):
# Stock's finally can win the race once our mounts are released.
mw = FakeMiddleware(["Tap/apps@snap", "Tap/apps/lidarr@snap"])
delete_snapshot_tree(mw, "Tap@snap")
delete_snapshot_tree(mw, "Tap@snap", list_snapshots=mw.list_snapshots)
assert mw.snapshots == []
def test_uses_a_single_recursive_delete_not_252_individual_ones(self):
# 252 sequential deletes are slow AND not atomic: a run killed part-way
# through leaves exactly the orphans this function exists to prevent.
mw = FakeMiddleware(["Tap@snap", "Tap/apps@snap", "Tap/apps/lidarr@snap"])
delete_snapshot_tree(mw, "Tap@snap")
delete_snapshot_tree(mw, "Tap@snap", list_snapshots=mw.list_snapshots)
assert mw.snapshots == []
deletes = [a for m, a in mw.calls if m == "zfs.snapshot.delete"]
deletes = [a for m, a in mw.calls if m.endswith(".delete")]
assert len(deletes) == 1, "should be ONE recursive call, not one per snapshot"
assert deletes[0][1] == {"recursive": True}
assert not [m for m, _a in mw.calls if m == "zfs.snapshot.query"], (
assert not [m for m, _a in mw.calls if m.endswith(".query")], (
"no enumeration needed on the fast path"
)
def test_survives_recursive_and_query_failure_by_deleting_the_parent(self):
class Broken(FakeMiddleware):
def call_sync(self, method, *args):
if method == "zfs.snapshot.query":
if method.endswith(".query"):
raise RuntimeError("boom")
if method == "zfs.snapshot.delete" and len(args) > 1:
if method.endswith(".delete") and len(args) > 1:
raise RuntimeError("recursive delete unavailable")
return super().call_sync(method, *args)
mw = Broken(["Tap@snap"])
delete_snapshot_tree(mw, "Tap@snap")
delete_snapshot_tree(mw, "Tap@snap", list_snapshots=mw.list_snapshots)
assert mw.snapshots == []
def test_leaves_unrelated_snapshots_alone_when_the_tree_is_gone(self):
mw = FakeMiddleware(["Tap@unrelated"])
delete_snapshot_tree(mw, "Tap@snap")
delete_snapshot_tree(mw, "Tap@snap", list_snapshots=mw.list_snapshots)
assert mw.snapshots == ["Tap@unrelated"]
@@ -692,7 +726,7 @@ class BusyMiddleware(FakeMiddleware):
self.attempts = 0
def call_sync(self, method, *args):
if method == "zfs.snapshot.delete":
if method.endswith(".delete"):
name = args[0]
opts = args[1] if len(args) > 1 else {}
if opts.get("recursive"):
@@ -713,7 +747,7 @@ class TestDeleteRetriesAndReportsSurvivors:
["Tap@snap", "Tap/apps@snap", "Tap/apps/prometheus@snap"],
busy=["Tap/apps/prometheus@snap"], busy_for=1,
)
survivors = tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None)
survivors = tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None, list_snapshots=mw.list_snapshots)
assert survivors == []
assert mw.snapshots == []
@@ -725,7 +759,7 @@ class TestDeleteRetriesAndReportsSurvivors:
["Tap@snap", "Tap/apps/prometheus@snap"],
busy=["Tap/apps/prometheus@snap"], busy_for=99,
)
survivors = tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None)
survivors = tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None, list_snapshots=mw.list_snapshots)
assert survivors == ["Tap/apps/prometheus@snap"]
assert mw.snapshots == ["Tap/apps/prometheus@snap"]
@@ -742,7 +776,7 @@ class TestDeleteRetriesAndReportsSurvivors:
return real(method, *args)
mw.call_sync = spy
tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None)
tn.delete_snapshot_tree(mw, "Tap@snap", sleep=lambda _s: None, list_snapshots=mw.list_snapshots)
assert order[0] == ("release", "snap"), order
@@ -1002,6 +1036,7 @@ class TestGarbageCollectorExecution:
remaining = tn.gc_stale_snapshots(
mw, "cloud_backup-5", "Tap@cloud_backup-5-20260714115900",
now=now, mounts_file=str(mounts),
list_snapshots=mw.list_snapshots,
)
assert remaining == []
assert mw.snapshots == [
@@ -1026,6 +1061,7 @@ class TestGarbageCollectorExecution:
remaining = tn.gc_stale_snapshots(
mw, "cloud_backup-5", "Tap@cloud_backup-5-20260714115900",
now=now, mounts_file=str(mounts),
list_snapshots=mw.list_snapshots,
)
assert remaining == [orphan]
@@ -1039,7 +1075,7 @@ class TestGarbageCollectorExecution:
class Broken(FakeMiddleware):
def call_sync(self, method, *args):
if method == "zfs.snapshot.query":
if method.endswith(".query"):
raise RuntimeError("middleware is having a day")
return super().call_sync(method, *args)
@@ -1049,3 +1085,96 @@ class TestGarbageCollectorExecution:
now=dt.datetime(2026, 7, 14, 12, 0, 0, tzinfo=dt.UTC),
mounts_file=str(mounts),
) == []
class TestEnumerationComesFromZfsNotMiddleware:
"""The bug that a source check can never catch, found only by running it.
Porting the deleted private `zfs.dataset.query` to the public
`pool.dataset.query` looked obviously right: the method exists, it is
documented, iX will not delete it. Every test passed and `compat.py` went green
on TrueNAS 26.
It was wrong. The public query applies a VISIBILITY POLICY -- on a real box it
returns 205 of 274 datasets, hiding `ix-apps/*`, `.system/*` and `.ix-virt/*`.
On the production pool that is 84 of 270, and `ix-apps` holds LIVE APPLICATION
DATA. The staging plan would have omitted every one of them, and `plan_staging`
would never have seen them, so they would not even appear in `skipped`. A green
backup, silently missing data -- the precise failure this module exists to
prevent.
The snapshot query lies the same way, so the sweep would orphan one snapshot per
hidden dataset, forever.
Hence: READ from ZFS, MUTATE through middleware. These tests hold that line.
"""
def test_query_filesystems_shells_out_to_zfs(self):
import truecloud_nested as tn
seen = []
class R:
returncode = 0
stdout = (
"scratch\t/mnt/scratch\tyes\n"
"scratch/ix-apps\t/mnt/scratch/ix-apps\tyes\n" # middleware HIDES this one
"scratch/.system\tlegacy\tno\n"
)
stderr = ""
def runner(cmd):
seen.append(cmd)
return R()
rows = tn.query_filesystems(runner=runner)
assert seen and seen[0][0] == "zfs", "must read ZFS, not call middleware"
names = [r["name"] for r in rows]
assert "scratch/ix-apps" in names, (
"ix-apps is exactly what pool.dataset.query hides, and exactly what "
"holds live app data. If it is not here the backup omits it silently."
)
# ...and it still speaks the shape the planner expects.
row = next(r for r in rows if r["name"] == "scratch/.system")
assert row["properties"]["mountpoint"]["value"] == "legacy"
assert row["properties"]["mounted"]["value"] == "no"
def test_a_failing_zfs_raises_rather_than_returning_an_empty_list(self):
# The whole failure class in one assertion. "No datasets" and "the command
# broke" must never look the same: a caller that cannot tell them apart
# stages nothing, sweeps nothing, and reports success.
import truecloud_nested as tn
class R:
returncode = 1
stdout = ""
stderr = "cannot open 'scratch': no such pool"
with pytest.raises(tn.ZfsError, match="no such pool"):
tn.query_filesystems(runner=lambda cmd: R())
with pytest.raises(tn.ZfsError):
tn.list_snapshot_names("scratch", runner=lambda cmd: R())
def test_list_snapshot_names_reads_the_whole_tree_from_zfs(self):
import truecloud_nested as tn
seen = []
class R:
returncode = 0
stdout = "scratch@s\nscratch/ix-apps@s\n"
stderr = ""
def runner(cmd):
seen.append(cmd)
return R()
names = tn.list_snapshot_names("scratch", runner=runner)
assert names == ["scratch@s", "scratch/ix-apps@s"]
assert "-t" in seen[0] and "snapshot" in seen[0] and "-r" in seen[0]
assert "scratch/ix-apps@s" in names, (
"pool.snapshot.query hides this; a sweep that cannot see it orphans it "
"on every single run, forever"
)