libbtrfsutil: add filesystem sync helpers

Namely, sync, start_sync, and wait_sync.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

5 files changed, 193 insertions, 0 deletions

diff --git a/libbtrfsutil/python/btrfsutilpy.h b/libbtrfsutil/python/btrfsutilpy.h
index 3b5d7849..02039ba1 100644
--- a/libbtrfsutil/python/btrfsutilpy.h
+++ b/libbtrfsutil/python/btrfsutilpy.h
@@ -58,6 +58,10 @@ void SetFromBtrfsUtilErrorWithPaths(enum btrfs_util_error err,
 				    struct path_arg *path1,
 				    struct path_arg *path2);
 
+PyObject *filesystem_sync(PyObject *self, PyObject *args, PyObject *kwds);
+PyObject *start_sync(PyObject *self, PyObject *args, PyObject *kwds);
+PyObject *wait_sync(PyObject *self, PyObject *args, PyObject *kwds);
+
 void add_module_constants(PyObject *m);
 
 #endif /* BTRFSUTILPY_H */
diff --git a/libbtrfsutil/python/filesystem.c b/libbtrfsutil/python/filesystem.c
new file mode 100644
index 00000000..627ed193
--- /dev/null
+++ b/libbtrfsutil/python/filesystem.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2018 Facebook
+ *
+ * This file is part of libbtrfsutil.
+ *
+ * libbtrfsutil is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libbtrfsutil is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libbtrfsutil.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "btrfsutilpy.h"
+
+PyObject *filesystem_sync(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	static char *keywords[] = {"path", NULL};
+	struct path_arg path = {.allow_fd = true};
+	enum btrfs_util_error err;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&:sync", keywords,
+					 &path_converter, &path))
+		return NULL;
+
+	if (path.path)
+		err = btrfs_util_sync(path.path);
+	else
+		err = btrfs_util_sync_fd(path.fd);
+	if (err) {
+		SetFromBtrfsUtilErrorWithPath(err, &path);
+		path_cleanup(&path);
+		return NULL;
+	}
+
+	path_cleanup(&path);
+	Py_RETURN_NONE;
+}
+
+PyObject *start_sync(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	static char *keywords[] = {"path", NULL};
+	struct path_arg path = {.allow_fd = true};
+	uint64_t transid;
+	enum btrfs_util_error err;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&:start_sync", keywords,
+					 &path_converter, &path))
+		return NULL;
+
+	if (path.path)
+		err = btrfs_util_start_sync(path.path, &transid);
+	else
+		err = btrfs_util_start_sync_fd(path.fd, &transid);
+	if (err) {
+		SetFromBtrfsUtilErrorWithPath(err, &path);
+		path_cleanup(&path);
+		return NULL;
+	}
+
+	path_cleanup(&path);
+	return PyLong_FromUnsignedLongLong(transid);
+}
+
+PyObject *wait_sync(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	static char *keywords[] = {"path", "transid", NULL};
+	struct path_arg path = {.allow_fd = true};
+	unsigned long long transid = 0;
+	enum btrfs_util_error err;
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&|K:wait_sync", keywords,
+					 &path_converter, &path, &transid))
+		return NULL;
+
+	if (path.path)
+		err = btrfs_util_wait_sync(path.path, transid);
+	else
+		err = btrfs_util_wait_sync_fd(path.fd, transid);
+	if (err) {
+		SetFromBtrfsUtilErrorWithPath(err, &path);
+		path_cleanup(&path);
+		return NULL;
+	}
+
+	path_cleanup(&path);
+	Py_RETURN_NONE;
+}
diff --git a/libbtrfsutil/python/module.c b/libbtrfsutil/python/module.c
index 24d962dc..9c1a864a 100644
--- a/libbtrfsutil/python/module.c
+++ b/libbtrfsutil/python/module.c
@@ -132,6 +132,27 @@ void path_cleanup(struct path_arg *path)
 }
 
 static PyMethodDef btrfsutil_methods[] = {
+	{"sync", (PyCFunction)filesystem_sync,
+	 METH_VARARGS | METH_KEYWORDS,
+	 "sync(path)\n\n"
+	 "Sync a specific Btrfs filesystem.\n\n"
+	 "Arguments:\n"
+	 "path -- string, bytes, path-like object, or open file descriptor"},
+	{"start_sync", (PyCFunction)start_sync,
+	 METH_VARARGS | METH_KEYWORDS,
+	 "start_sync(path) -> int\n\n"
+	 "Start a sync on a specific Btrfs filesystem and return the\n"
+	 "transaction ID.\n\n"
+	 "Arguments:\n"
+	 "path -- string, bytes, path-like object, or open file descriptor"},
+	{"wait_sync", (PyCFunction)wait_sync,
+	 METH_VARARGS | METH_KEYWORDS,
+	 "wait_sync(path, transid=0)\n\n"
+	 "Wait for a transaction to sync.\n"
+	 "Arguments:\n"
+	 "path -- string, bytes, path-like object, or open file descriptor\n"
+	 "transid -- int transaction ID to wait for, or zero for the current\n"
+	 "transaction"},
 	{},
 };
 
diff --git a/libbtrfsutil/python/setup.py b/libbtrfsutil/python/setup.py
index 478510ce..df44809f 100755
--- a/libbtrfsutil/python/setup.py
+++ b/libbtrfsutil/python/setup.py
@@ -90,6 +90,7 @@ module = Extension(
     sources=[
         'constants.c',
         'error.c',
+        'filesystem.c',
         'module.c',
         'qgroup.c',
     ],
diff --git a/libbtrfsutil/python/tests/test_filesystem.py b/libbtrfsutil/python/tests/test_filesystem.py
new file mode 100644
index 00000000..006a6b1e
--- /dev/null
+++ b/libbtrfsutil/python/tests/test_filesystem.py
@@ -0,0 +1,73 @@
+# Copyright (C) 2018 Facebook
+#
+# This file is part of libbtrfsutil.
+#
+# libbtrfsutil is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# libbtrfsutil is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with libbtrfsutil.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import time
+
+import btrfsutil
+from tests import BtrfsTestCase, HAVE_PATH_LIKE
+
+
+def touch(path):
+    now = time.time()
+    os.utime(path, (now, now))
+
+
+class TestSubvolume(BtrfsTestCase):
+    def super_generation(self):
+        with open(self.image, 'rb') as f:
+            # csum is 32 bytes, fsid is 16 bytes, bytenr is 8 bytes, flags is 8
+            # bytes
+            f.seek(65536 + 32 + 16 + 8 + 8)
+            self.assertEqual(f.read(8), b'_BHRfS_M')
+            return int.from_bytes(f.read(8), 'little')
+
+    def test_sync(self):
+        old_generation = self.super_generation()
+        for arg in self.path_or_fd(self.mountpoint):
+            with self.subTest(type=type(arg)):
+                touch(arg)
+                btrfsutil.sync(arg)
+                new_generation = self.super_generation()
+                self.assertGreater(new_generation, old_generation)
+                old_generation = new_generation
+
+    def test_start_sync(self):
+        old_generation = self.super_generation()
+        for arg in self.path_or_fd(self.mountpoint):
+            with self.subTest(type=type(arg)):
+                touch(arg)
+                transid = btrfsutil.start_sync(arg)
+                self.assertGreater(transid, old_generation)
+
+    def test_wait_sync(self):
+        old_generation = self.super_generation()
+        for arg in self.path_or_fd(self.mountpoint):
+            with self.subTest(type=type(arg)):
+                touch(arg)
+                transid = btrfsutil.start_sync(arg)
+                btrfsutil.wait_sync(arg, transid)
+                new_generation = self.super_generation()
+                self.assertGreater(new_generation, old_generation)
+                old_generation = new_generation
+
+                touch(arg)
+                btrfsutil.start_sync(arg)
+                btrfsutil.wait_sync(arg)
+                new_generation = self.super_generation()
+                self.assertGreater(new_generation, old_generation)
+                old_generation = new_generation