From f676a8ad118ecba7fbf4edc77b91f788c6fa7e7c Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Thu, 18 Jan 2018 13:15:32 -0800 Subject: 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 Signed-off-by: David Sterba --- libbtrfsutil/btrfsutil.h | 34 ++++++++ libbtrfsutil/python/btrfsutilpy.h | 1 + libbtrfsutil/python/module.c | 8 ++ libbtrfsutil/python/subvolume.c | 29 +++++++ libbtrfsutil/python/tests/test_qgroup.py | 11 +++ libbtrfsutil/python/tests/test_subvolume.py | 49 +++++++++++- libbtrfsutil/subvolume.c | 115 ++++++++++++++++++++++++++++ 7 files changed, 246 insertions(+), 1 deletion(-) diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h index c4650097..654dd998 100644 --- a/libbtrfsutil/btrfsutil.h +++ b/libbtrfsutil/btrfsutil.h @@ -149,6 +149,40 @@ 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(). diff --git a/libbtrfsutil/python/btrfsutilpy.h b/libbtrfsutil/python/btrfsutilpy.h index 47125d85..19ba71f3 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 18e8c5aa..deb26875 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 4aab06a5..6f2080ee 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 a590464b..19e6b05a 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 44b1d7f0..f6c5958d 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 7ae8142c..6ac372ca 100644 --- a/libbtrfsutil/subvolume.c +++ b/libbtrfsutil/subvolume.c @@ -19,6 +19,8 @@ #include #include +#include +#include #include #include #include @@ -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; +} -- cgit v1.2.3