diff options
author | Omar Sandoval <osandov@fb.com> | 2018-01-18 14:23:23 -0800 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2018-03-06 11:28:37 +0100 |
commit | cfa89b30821fedb48ca163a9c1128c4db596c911 (patch) | |
tree | bf04b519f0b9df71f542ec2ee8d9cbc2f4869dff /libbtrfsutil | |
parent | 0b8512b7f5a6106efcab371471c472572a55367e (diff) |
libbtrfsutil: add btrfs_util_create_snapshot()
Thanks to subvolume iterators, we can also implement recursive snapshot
fairly easily.
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.h | 59 | ||||
-rw-r--r-- | libbtrfsutil/python/btrfsutilpy.h | 1 | ||||
-rw-r--r-- | libbtrfsutil/python/module.c | 11 | ||||
-rw-r--r-- | libbtrfsutil/python/subvolume.c | 49 | ||||
-rw-r--r-- | libbtrfsutil/python/tests/test_qgroup.py | 10 | ||||
-rw-r--r-- | libbtrfsutil/python/tests/test_subvolume.py | 55 | ||||
-rw-r--r-- | libbtrfsutil/subvolume.c | 167 |
7 files changed, 352 insertions, 0 deletions
diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h index 09a71c32..ccb2c177 100644 --- a/libbtrfsutil/btrfsutil.h +++ b/libbtrfsutil/btrfsutil.h @@ -391,6 +391,65 @@ enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd, uint64_t *async_transid, struct btrfs_util_qgroup_inherit *qgroup_inherit); +/** + * BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE - Also snapshot subvolumes beneath the + * source subvolume onto the same location on the new snapshot. + * + * Note that this is currently implemented in userspace non-atomically. Because + * it modifies the newly-created snapshot, it cannot be combined with + * %BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY. It requires appropriate privilege + * (CAP_SYS_ADMIN). + */ +#define BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE (1 << 0) +/** + * BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY - Create a read-only snapshot. + */ +#define BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY (1 << 1) +#define BTRFS_UTIL_CREATE_SNAPSHOT_MASK ((1 << 2) - 1) + +/** + * btrfs_util_create_snapshot() - Create a new snapshot from a source subvolume + * path. + * @source: Path of the existing subvolume to snapshot. + * @path: Where to create the snapshot. + * @flags: Bitmask of BTRFS_UTIL_CREATE_SNAPSHOT_* flags. + * @async_transid: See btrfs_util_create_subvolume(). If + * %BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE was in @flags, then this will contain + * the largest transaction ID of all created subvolumes. + * @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_snapshot(const char *source, + const char *path, int flags, + uint64_t *async_transid, + struct btrfs_util_qgroup_inherit *qgroup_inherit); + +/** + * btrfs_util_create_snapshot_fd() - See btrfs_util_create_snapshot(). + */ +enum btrfs_util_error btrfs_util_create_snapshot_fd(int fd, const char *path, + int flags, + uint64_t *async_transid, + struct btrfs_util_qgroup_inherit *qgroup_inherit); + +/** + * btrfs_util_create_snapshot_fd2() - Create a new snapshot from a source + * subvolume file descriptor and a target parent file descriptor and name. + * @fd: File descriptor of the existing subvolume to snapshot. + * @parent_fd: File descriptor of the parent directory where the snapshot should + * be created. + * @name: Name of the snapshot to create. + * @flags: See btrfs_util_create_snapshot(). + * @async_transid: See btrfs_util_create_snapshot(). + * @qgroup_inherit: See btrfs_util_create_snapshot(). + */ +enum btrfs_util_error btrfs_util_create_snapshot_fd2(int fd, int parent_fd, + const char *name, + int flags, + uint64_t *async_transid, + struct btrfs_util_qgroup_inherit *qgroup_inherit); + struct btrfs_util_subvolume_iterator; /** diff --git a/libbtrfsutil/python/btrfsutilpy.h b/libbtrfsutil/python/btrfsutilpy.h index 79ac2eec..59c7e994 100644 --- a/libbtrfsutil/python/btrfsutilpy.h +++ b/libbtrfsutil/python/btrfsutilpy.h @@ -73,6 +73,7 @@ PyObject *set_subvolume_read_only(PyObject *self, PyObject *args, PyObject *kwds PyObject *get_default_subvolume(PyObject *self, PyObject *args, PyObject *kwds); PyObject *set_default_subvolume(PyObject *self, PyObject *args, PyObject *kwds); PyObject *create_subvolume(PyObject *self, PyObject *args, PyObject *kwds); +PyObject *create_snapshot(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 9a237142..3f0f6170 100644 --- a/libbtrfsutil/python/module.c +++ b/libbtrfsutil/python/module.c @@ -216,6 +216,17 @@ static PyMethodDef btrfsutil_methods[] = { "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"}, + {"create_snapshot", (PyCFunction)create_snapshot, + METH_VARARGS | METH_KEYWORDS, + "create_snapshot(source, path, recursive=False, read_only=False, async=False)\n\n" + "Create a new snapshot.\n\n" + "Arguments:\n" + "source -- string, bytes, path-like object, or open file descriptor\n" + "path -- string, bytes, or path-like object\n" + "recursive -- also snapshot child subvolumes\n" + "read_only -- create a read-only snapshot\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 6c384583..a158ade7 100644 --- a/libbtrfsutil/python/subvolume.c +++ b/libbtrfsutil/python/subvolume.c @@ -349,6 +349,55 @@ PyObject *create_subvolume(PyObject *self, PyObject *args, PyObject *kwds) Py_RETURN_NONE; } +PyObject *create_snapshot(PyObject *self, PyObject *args, PyObject *kwds) +{ + static char *keywords[] = { + "source", "path", "recursive", "read_only", "async", + "qgroup_inherit", NULL, + }; + struct path_arg src = {.allow_fd = true}, dst = {.allow_fd = false}; + enum btrfs_util_error err; + int recursive = 0, read_only = 0, async = 0; + int flags = 0; + QgroupInherit *inherit = NULL; + uint64_t transid; + + if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&O&|pppO!:create_snapshot", + keywords, &path_converter, &src, + &path_converter, &dst, &recursive, + &read_only, &async, + &QgroupInherit_type, &inherit)) + return NULL; + + if (recursive) + flags |= BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE; + if (read_only) + flags |= BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY; + + if (src.path) { + err = btrfs_util_create_snapshot(src.path, dst.path, flags, + async ? &transid : NULL, + inherit ? inherit->inherit : NULL); + } else { + err = btrfs_util_create_snapshot_fd(src.fd, dst.path, flags, + async ? &transid : NULL, + inherit ? inherit->inherit : NULL); + } + if (err) { + SetFromBtrfsUtilErrorWithPaths(err, &src, &dst); + path_cleanup(&src); + path_cleanup(&dst); + return NULL; + } + + path_cleanup(&src); + path_cleanup(&dst); + if (async) + return PyLong_FromUnsignedLongLong(transid); + else + Py_RETURN_NONE; +} + typedef struct { PyObject_HEAD struct btrfs_util_subvolume_iterator *iter; diff --git a/libbtrfsutil/python/tests/test_qgroup.py b/libbtrfsutil/python/tests/test_qgroup.py index 19e6b05a..74fc46b6 100644 --- a/libbtrfsutil/python/tests/test_qgroup.py +++ b/libbtrfsutil/python/tests/test_qgroup.py @@ -31,6 +31,16 @@ class TestQgroup(BtrfsTestCase): btrfsutil.create_subvolume(subvol, qgroup_inherit=inherit) + def test_snapshot_inherit(self): + subvol = os.path.join(self.mountpoint, 'subvol') + snapshot = os.path.join(self.mountpoint, 'snapshot') + + inherit = btrfsutil.QgroupInherit() + inherit.add_group(5) + + btrfsutil.create_subvolume(subvol) + btrfsutil.create_snapshot(subvol, snapshot, qgroup_inherit=inherit) + class TestQgroupInherit(unittest.TestCase): def test_new(self): diff --git a/libbtrfsutil/python/tests/test_subvolume.py b/libbtrfsutil/python/tests/test_subvolume.py index b43beca7..2951154e 100644 --- a/libbtrfsutil/python/tests/test_subvolume.py +++ b/libbtrfsutil/python/tests/test_subvolume.py @@ -129,6 +129,13 @@ class TestSubvolume(BtrfsTestCase): self.assertEqual(info.stime, 0) self.assertEqual(info.rtime, 0) + subvol_uuid = info.uuid + snapshot = os.path.join(self.mountpoint, 'snapshot') + btrfsutil.create_snapshot(subvol, snapshot) + + info = btrfsutil.subvolume_info(snapshot) + self.assertEqual(info.parent_uuid, subvol_uuid) + # TODO: test received_uuid, stransid, rtransid, stime, and rtime for arg in self.path_or_fd(self.mountpoint): @@ -215,6 +222,54 @@ class TestSubvolume(BtrfsTestCase): self.assertTrue(os.WIFEXITED(wstatus)) self.assertEqual(os.WEXITSTATUS(wstatus), 0) + def test_create_snapshot(self): + subvol = os.path.join(self.mountpoint, 'subvol') + + btrfsutil.create_subvolume(subvol) + os.mkdir(os.path.join(subvol, 'dir')) + + for i, arg in enumerate(self.path_or_fd(subvol)): + with self.subTest(type=type(arg)): + snapshots_dir = os.path.join(self.mountpoint, 'snapshots{}'.format(i)) + os.mkdir(snapshots_dir) + snapshot = os.path.join(snapshots_dir, 'snapshot') + + btrfsutil.create_snapshot(subvol, snapshot + '1') + self.assertTrue(btrfsutil.is_subvolume(snapshot + '1')) + self.assertTrue(os.path.exists(os.path.join(snapshot + '1', 'dir'))) + + btrfsutil.create_snapshot(subvol, (snapshot + '2').encode()) + self.assertTrue(btrfsutil.is_subvolume(snapshot + '2')) + self.assertTrue(os.path.exists(os.path.join(snapshot + '2', 'dir'))) + + if HAVE_PATH_LIKE: + btrfsutil.create_snapshot(subvol, PurePath(snapshot + '3')) + self.assertTrue(btrfsutil.is_subvolume(snapshot + '3')) + self.assertTrue(os.path.exists(os.path.join(snapshot + '3', 'dir'))) + + nested_subvol = os.path.join(subvol, 'nested') + more_nested_subvol = os.path.join(nested_subvol, 'more_nested') + btrfsutil.create_subvolume(nested_subvol) + btrfsutil.create_subvolume(more_nested_subvol) + os.mkdir(os.path.join(more_nested_subvol, 'nested_dir')) + + snapshot = os.path.join(self.mountpoint, 'snapshot') + + btrfsutil.create_snapshot(subvol, snapshot + '1') + # Dummy subvolume. + self.assertEqual(os.stat(os.path.join(snapshot + '1', 'nested')).st_ino, 2) + self.assertFalse(os.path.exists(os.path.join(snapshot + '1', 'nested', 'more_nested'))) + + btrfsutil.create_snapshot(subvol, snapshot + '2', recursive=True) + self.assertTrue(os.path.exists(os.path.join(snapshot + '2', 'nested/more_nested/nested_dir'))) + + transid = btrfsutil.create_snapshot(subvol, snapshot + '3', recursive=True, async=True) + self.assertTrue(os.path.exists(os.path.join(snapshot + '3', 'nested/more_nested/nested_dir'))) + self.assertGreater(transid, 0) + + btrfsutil.create_snapshot(subvol, snapshot + '4', read_only=True) + self.assertTrue(btrfsutil.get_subvolume_read_only(snapshot + '4')) + def test_subvolume_iterator(self): pwd = os.getcwd() try: diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c index 4f71cb06..28b38e5a 100644 --- a/libbtrfsutil/subvolume.c +++ b/libbtrfsutil/subvolume.c @@ -838,6 +838,173 @@ out_iter: return err; } +static enum btrfs_util_error snapshot_subvolume_children(int fd, int parent_fd, + const char *name, + uint64_t *async_transid) +{ + struct btrfs_util_subvolume_iterator *iter; + enum btrfs_util_error err; + int dstfd; + + dstfd = openat(parent_fd, name, O_RDONLY); + if (dstfd == -1) + return BTRFS_UTIL_ERROR_OPEN_FAILED; + + err = btrfs_util_create_subvolume_iterator_fd(fd, 0, 0, &iter); + if (err) + goto out; + + for (;;) { + char child_name[BTRFS_SUBVOL_NAME_MAX + 1]; + char *child_path; + int child_fd, new_parent_fd; + uint64_t tmp_transid; + + err = btrfs_util_subvolume_iterator_next(iter, &child_path, + NULL); + if (err) { + if (err == BTRFS_UTIL_ERROR_STOP_ITERATION) + err = BTRFS_UTIL_OK; + break; + } + + /* Remove the placeholder directory. */ + if (unlinkat(dstfd, child_path, AT_REMOVEDIR) == -1) { + free(child_path); + err = BTRFS_UTIL_ERROR_RMDIR_FAILED; + break; + } + + child_fd = openat(fd, child_path, O_RDONLY); + if (child_fd == -1) { + free(child_path); + err = BTRFS_UTIL_ERROR_OPEN_FAILED; + break; + } + + err = openat_parent_and_name(dstfd, child_path, child_name, + sizeof(child_name), + &new_parent_fd); + free(child_path); + if (err) { + SAVE_ERRNO_AND_CLOSE(child_fd); + break; + } + + err = btrfs_util_create_snapshot_fd2(child_fd, new_parent_fd, + child_name, 0, + async_transid ? &tmp_transid : NULL, + NULL); + SAVE_ERRNO_AND_CLOSE(child_fd); + SAVE_ERRNO_AND_CLOSE(new_parent_fd); + if (err) + break; + if (async_transid && tmp_transid > *async_transid) + *async_transid = tmp_transid; + } + + btrfs_util_destroy_subvolume_iterator(iter); +out: + SAVE_ERRNO_AND_CLOSE(dstfd); + return err; +} + +PUBLIC enum btrfs_util_error btrfs_util_create_snapshot(const char *source, + const char *path, + int flags, + uint64_t *async_transid, + struct btrfs_util_qgroup_inherit *qgroup_inherit) +{ + enum btrfs_util_error err; + int fd; + + fd = open(source, O_RDONLY); + if (fd == -1) + return BTRFS_UTIL_ERROR_OPEN_FAILED; + + err = btrfs_util_create_snapshot_fd(fd, path, flags, async_transid, + qgroup_inherit); + SAVE_ERRNO_AND_CLOSE(fd); + return err; +} + +PUBLIC enum btrfs_util_error btrfs_util_create_snapshot_fd(int fd, + 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_snapshot_fd2(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_snapshot_fd2(int 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 = {.fd = fd}; + enum btrfs_util_error err; + size_t len; + int ret; + + if ((flags & ~BTRFS_UTIL_CREATE_SNAPSHOT_MASK) || + ((flags & BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY) && + (flags & BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE))) { + errno = EINVAL; + return BTRFS_UTIL_ERROR_INVALID_ARGUMENT; + } + + if (flags & BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY) + args.flags |= BTRFS_SUBVOL_RDONLY; + 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_SNAP_CREATE_V2, &args); + if (ret == -1) + return BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED; + + if (async_transid) + *async_transid = args.transid; + + if (flags & BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE) { + err = snapshot_subvolume_children(fd, parent_fd, name, + async_transid); + if (err) + return err; + } + + return BTRFS_UTIL_OK; +} + PUBLIC void btrfs_util_destroy_subvolume_iterator(struct btrfs_util_subvolume_iterator *iter) { if (iter) { |