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authorOmar Sandoval <osandov@fb.com>2018-01-18 13:15:32 -0800
committerDavid Sterba <dsterba@suse.com>2018-03-06 11:28:36 +0100
commitf676a8ad118ecba7fbf4edc77b91f788c6fa7e7c (patch)
tree53734d782f62cdb026106a79cc203dead1878a79 /libbtrfsutil
parent92d4035074dd5234f1c3fd263947dde1f9bb288e (diff)
libbtrfsutil: add btrfs_util_create_subvolume()
Doing the ioctl() directly isn't too bad, but passing in a full path is more convenient than opening the parent and passing the path component. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'libbtrfsutil')
-rw-r--r--libbtrfsutil/btrfsutil.h34
-rw-r--r--libbtrfsutil/python/btrfsutilpy.h1
-rw-r--r--libbtrfsutil/python/module.c8
-rw-r--r--libbtrfsutil/python/subvolume.c29
-rw-r--r--libbtrfsutil/python/tests/test_qgroup.py11
-rw-r--r--libbtrfsutil/python/tests/test_subvolume.py49
-rw-r--r--libbtrfsutil/subvolume.c115
7 files changed, 246 insertions, 1 deletions
diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
index c465009..654dd99 100644
--- a/libbtrfsutil/btrfsutil.h
+++ b/libbtrfsutil/btrfsutil.h
@@ -150,6 +150,40 @@ enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd, uint64_t *id_ret);
struct btrfs_util_qgroup_inherit;
/**
+ * btrfs_util_create_subvolume() - Create a new subvolume.
+ * @path: Where to create the subvolume.
+ * @flags: Must be zero.
+ * @async_transid: If not NULL, create the subvolume asynchronously (i.e.,
+ * without waiting for it to commit it to disk) and return the transaction ID
+ * that it was created in. This transaction ID can be waited on with
+ * btrfs_util_wait_sync().
+ * @qgroup_inherit: Qgroups to inherit from, or NULL.
+ *
+ * Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
+ */
+enum btrfs_util_error btrfs_util_create_subvolume(const char *path, int flags,
+ uint64_t *async_transid,
+ struct btrfs_util_qgroup_inherit *qgroup_inherit);
+
+/**
+ * btrfs_util_create_subvolume_fd() - Create a new subvolume given its parent
+ * and name.
+ * @parent_fd: File descriptor of the parent directory where the subvolume
+ * should be created.
+ * @name: Name of the subvolume to create.
+ * @flags: See btrfs_util_create_subvolume().
+ * @async_transid: See btrfs_util_create_subvolume().
+ * @qgroup_inherit: See btrfs_util_create_subvolume().
+ *
+ * Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
+ */
+enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
+ const char *name,
+ int flags,
+ uint64_t *async_transid,
+ struct btrfs_util_qgroup_inherit *qgroup_inherit);
+
+/**
* btrfs_util_create_qgroup_inherit() - Create a qgroup inheritance specifier
* for btrfs_util_create_subvolume() or btrfs_util_create_snapshot().
* @flags: Must be zero.
diff --git a/libbtrfsutil/python/btrfsutilpy.h b/libbtrfsutil/python/btrfsutilpy.h
index 47125d8..19ba71f 100644
--- a/libbtrfsutil/python/btrfsutilpy.h
+++ b/libbtrfsutil/python/btrfsutilpy.h
@@ -63,6 +63,7 @@ PyObject *start_sync(PyObject *self, PyObject *args, PyObject *kwds);
PyObject *wait_sync(PyObject *self, PyObject *args, PyObject *kwds);
PyObject *is_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
PyObject *subvolume_id(PyObject *self, PyObject *args, PyObject *kwds);
+PyObject *create_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
void add_module_constants(PyObject *m);
diff --git a/libbtrfsutil/python/module.c b/libbtrfsutil/python/module.c
index 18e8c5a..deb2687 100644
--- a/libbtrfsutil/python/module.c
+++ b/libbtrfsutil/python/module.c
@@ -165,6 +165,14 @@ static PyMethodDef btrfsutil_methods[] = {
"Get the ID of the subvolume containing a file.\n\n"
"Arguments:\n"
"path -- string, bytes, path-like object, or open file descriptor"},
+ {"create_subvolume", (PyCFunction)create_subvolume,
+ METH_VARARGS | METH_KEYWORDS,
+ "create_subvolume(path, async=False)\n\n"
+ "Create a new subvolume.\n\n"
+ "Arguments:\n"
+ "path -- string, bytes, or path-like object\n"
+ "async -- create the subvolume without waiting for it to commit to\n"
+ "disk and return the transaction ID"},
{},
};
diff --git a/libbtrfsutil/python/subvolume.c b/libbtrfsutil/python/subvolume.c
index 4aab06a..6f2080e 100644
--- a/libbtrfsutil/python/subvolume.c
+++ b/libbtrfsutil/python/subvolume.c
@@ -71,3 +71,32 @@ PyObject *subvolume_id(PyObject *self, PyObject *args, PyObject *kwds)
path_cleanup(&path);
return PyLong_FromUnsignedLongLong(id);
}
+
+PyObject *create_subvolume(PyObject *self, PyObject *args, PyObject *kwds)
+{
+ static char *keywords[] = {"path", "async", "qgroup_inherit", NULL};
+ struct path_arg path = {.allow_fd = false};
+ enum btrfs_util_error err;
+ int async = 0;
+ QgroupInherit *inherit = NULL;
+ uint64_t transid;
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&|pO!:create_subvolume",
+ keywords, &path_converter, &path,
+ &async, &QgroupInherit_type, &inherit))
+ return NULL;
+
+ err = btrfs_util_create_subvolume(path.path, 0, async ? &transid : NULL,
+ inherit ? inherit->inherit : NULL);
+ if (err) {
+ SetFromBtrfsUtilErrorWithPath(err, &path);
+ path_cleanup(&path);
+ return NULL;
+ }
+
+ path_cleanup(&path);
+ if (async)
+ return PyLong_FromUnsignedLongLong(transid);
+ else
+ Py_RETURN_NONE;
+}
diff --git a/libbtrfsutil/python/tests/test_qgroup.py b/libbtrfsutil/python/tests/test_qgroup.py
index a590464..19e6b05 100644
--- a/libbtrfsutil/python/tests/test_qgroup.py
+++ b/libbtrfsutil/python/tests/test_qgroup.py
@@ -19,6 +19,17 @@ import os
import unittest
import btrfsutil
+from tests import BtrfsTestCase
+
+
+class TestQgroup(BtrfsTestCase):
+ def test_subvolume_inherit(self):
+ subvol = os.path.join(self.mountpoint, 'subvol')
+
+ inherit = btrfsutil.QgroupInherit()
+ inherit.add_group(5)
+
+ btrfsutil.create_subvolume(subvol, qgroup_inherit=inherit)
class TestQgroupInherit(unittest.TestCase):
diff --git a/libbtrfsutil/python/tests/test_subvolume.py b/libbtrfsutil/python/tests/test_subvolume.py
index 44b1d7f..f6c5958 100644
--- a/libbtrfsutil/python/tests/test_subvolume.py
+++ b/libbtrfsutil/python/tests/test_subvolume.py
@@ -23,7 +23,7 @@ from pathlib import PurePath
import traceback
import btrfsutil
-from tests import BtrfsTestCase
+from tests import BtrfsTestCase, HAVE_PATH_LIKE
class TestSubvolume(BtrfsTestCase):
@@ -55,3 +55,50 @@ class TestSubvolume(BtrfsTestCase):
for arg in self.path_or_fd(dir):
with self.subTest(type=type(arg)):
self.assertEqual(btrfsutil.subvolume_id(arg), 5)
+
+ def test_create_subvolume(self):
+ subvol = os.path.join(self.mountpoint, 'subvol')
+
+ btrfsutil.create_subvolume(subvol + '1')
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '1'))
+ btrfsutil.create_subvolume((subvol + '2').encode())
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '2'))
+ if HAVE_PATH_LIKE:
+ btrfsutil.create_subvolume(PurePath(subvol + '3'))
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '3'))
+
+ pwd = os.getcwd()
+ try:
+ os.chdir(self.mountpoint)
+ btrfsutil.create_subvolume('subvol4')
+ self.assertTrue(btrfsutil.is_subvolume('subvol4'))
+ finally:
+ os.chdir(pwd)
+
+ btrfsutil.create_subvolume(subvol + '5/')
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '5'))
+
+ btrfsutil.create_subvolume(subvol + '6//')
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '6'))
+
+ transid = btrfsutil.create_subvolume(subvol + '7', async=True)
+ self.assertTrue(btrfsutil.is_subvolume(subvol + '7'))
+ self.assertGreater(transid, 0)
+
+ # Test creating subvolumes under '/' in a chroot.
+ pid = os.fork()
+ if pid == 0:
+ try:
+ os.chroot(self.mountpoint)
+ os.chdir('/')
+ btrfsutil.create_subvolume('/subvol8')
+ self.assertTrue(btrfsutil.is_subvolume('/subvol8'))
+ with self.assertRaises(btrfsutil.BtrfsUtilError):
+ btrfsutil.create_subvolume('/')
+ os._exit(0)
+ except Exception:
+ traceback.print_exc()
+ os._exit(1)
+ wstatus = os.waitpid(pid, 0)[1]
+ self.assertTrue(os.WIFEXITED(wstatus))
+ self.assertEqual(os.WEXITSTATUS(wstatus), 0)
diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 7ae8142..6ac372c 100644
--- a/libbtrfsutil/subvolume.c
+++ b/libbtrfsutil/subvolume.c
@@ -19,6 +19,8 @@
#include <errno.h>
#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
@@ -123,3 +125,116 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd,
return BTRFS_UTIL_OK;
}
+
+static enum btrfs_util_error openat_parent_and_name(int dirfd, const char *path,
+ char *name, size_t name_len,
+ int *fd)
+{
+ char *tmp_path, *slash, *dirname, *basename;
+ size_t len;
+
+ /* Ignore trailing slashes. */
+ len = strlen(path);
+ while (len > 1 && path[len - 1] == '/')
+ len--;
+
+ tmp_path = malloc(len + 1);
+ if (!tmp_path)
+ return BTRFS_UTIL_ERROR_NO_MEMORY;
+ memcpy(tmp_path, path, len);
+ tmp_path[len] = '\0';
+
+ slash = memrchr(tmp_path, '/', len);
+ if (slash == tmp_path) {
+ dirname = "/";
+ basename = tmp_path + 1;
+ } else if (slash) {
+ *slash = '\0';
+ dirname = tmp_path;
+ basename = slash + 1;
+ } else {
+ dirname = ".";
+ basename = tmp_path;
+ }
+
+ len = strlen(basename);
+ if (len >= name_len) {
+ free(tmp_path);
+ errno = ENAMETOOLONG;
+ return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+ }
+ memcpy(name, basename, len);
+ name[len] = '\0';
+
+ *fd = openat(dirfd, dirname, O_RDONLY | O_DIRECTORY);
+ if (*fd == -1) {
+ free(tmp_path);
+ return BTRFS_UTIL_ERROR_OPEN_FAILED;
+ }
+
+ free(tmp_path);
+ return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume(const char *path,
+ int flags,
+ uint64_t *async_transid,
+ struct btrfs_util_qgroup_inherit *qgroup_inherit)
+{
+ char name[BTRFS_SUBVOL_NAME_MAX + 1];
+ enum btrfs_util_error err;
+ int parent_fd;
+
+ err = openat_parent_and_name(AT_FDCWD, path, name, sizeof(name),
+ &parent_fd);
+ if (err)
+ return err;
+
+ err = btrfs_util_create_subvolume_fd(parent_fd, name, flags,
+ async_transid, qgroup_inherit);
+ SAVE_ERRNO_AND_CLOSE(parent_fd);
+ return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
+ const char *name,
+ int flags,
+ uint64_t *async_transid,
+ struct btrfs_util_qgroup_inherit *qgroup_inherit)
+{
+ struct btrfs_ioctl_vol_args_v2 args = {};
+ size_t len;
+ int ret;
+
+ if (flags) {
+ errno = EINVAL;
+ return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+ }
+
+ if (async_transid)
+ args.flags |= BTRFS_SUBVOL_CREATE_ASYNC;
+ if (qgroup_inherit) {
+ args.flags |= BTRFS_SUBVOL_QGROUP_INHERIT;
+ args.qgroup_inherit = (struct btrfs_qgroup_inherit *)qgroup_inherit;
+ args.size = (sizeof(*args.qgroup_inherit) +
+ args.qgroup_inherit->num_qgroups *
+ sizeof(args.qgroup_inherit->qgroups[0]));
+ }
+
+ len = strlen(name);
+ if (len >= sizeof(args.name)) {
+ errno = ENAMETOOLONG;
+ return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+ }
+ memcpy(args.name, name, len);
+ args.name[len] = '\0';
+
+ ret = ioctl(parent_fd, BTRFS_IOC_SUBVOL_CREATE_V2, &args);
+ if (ret == -1)
+ return BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED;
+
+ if (async_transid)
+ *async_transid = args.transid;
+
+ return BTRFS_UTIL_OK;
+}