1153 lines
35 KiB
C
1153 lines
35 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdlib.h>
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#include <sys/vfs.h>
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#include <sys/stat.h>
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#ifdef HAVE_LINUX_BTRFS_H
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#include <linux/btrfs.h>
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#endif
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#include "missing.h"
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#include "util.h"
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#include "path-util.h"
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#include "macro.h"
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#include "copy.h"
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#include "selinux-util.h"
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#include "smack-util.h"
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#include "fileio.h"
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#include "btrfs-ctree.h"
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#include "btrfs-util.h"
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/* WARNING: Be careful with file system ioctls! When we get an fd, we
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* need to make sure it either refers to only a regular file or
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* directory, or that it is located on btrfs, before invoking any
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* btrfs ioctls. The ioctl numbers are reused by some device drivers
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* (such as DRM), and hence might have bad effects when invoked on
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* device nodes (that reference drivers) rather than fds to normal
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* files or directories. */
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static int validate_subvolume_name(const char *name) {
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if (!filename_is_valid(name))
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return -EINVAL;
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if (strlen(name) > BTRFS_SUBVOL_NAME_MAX)
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return -E2BIG;
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return 0;
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}
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static int open_parent(const char *path, int flags) {
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_cleanup_free_ char *parent = NULL;
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int r, fd;
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assert(path);
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r = path_get_parent(path, &parent);
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if (r < 0)
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return r;
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fd = open(parent, flags);
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if (fd < 0)
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return -errno;
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return fd;
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}
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static int extract_subvolume_name(const char *path, const char **subvolume) {
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const char *fn;
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int r;
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assert(path);
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assert(subvolume);
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fn = basename(path);
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r = validate_subvolume_name(fn);
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if (r < 0)
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return r;
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*subvolume = fn;
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return 0;
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}
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int btrfs_is_filesystem(int fd) {
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struct statfs sfs;
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assert(fd >= 0);
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if (fstatfs(fd, &sfs) < 0)
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return -errno;
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return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
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}
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int btrfs_is_subvol(int fd) {
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struct stat st;
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assert(fd >= 0);
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/* On btrfs subvolumes always have the inode 256 */
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if (fstat(fd, &st) < 0)
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return -errno;
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if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
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return 0;
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return btrfs_is_filesystem(fd);
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}
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int btrfs_subvol_make(const char *path) {
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struct btrfs_ioctl_vol_args args = {};
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_cleanup_close_ int fd = -1;
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const char *subvolume;
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int r;
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assert(path);
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r = extract_subvolume_name(path, &subvolume);
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if (r < 0)
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return r;
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fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
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if (fd < 0)
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return fd;
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strncpy(args.name, subvolume, sizeof(args.name)-1);
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if (ioctl(fd, BTRFS_IOC_SUBVOL_CREATE, &args) < 0)
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return -errno;
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return 0;
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}
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int btrfs_subvol_make_label(const char *path) {
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int r;
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assert(path);
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r = mac_selinux_create_file_prepare(path, S_IFDIR);
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if (r < 0)
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return r;
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r = btrfs_subvol_make(path);
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mac_selinux_create_file_clear();
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if (r < 0)
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return r;
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return mac_smack_fix(path, false, false);
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}
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int btrfs_subvol_set_read_only_fd(int fd, bool b) {
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uint64_t flags, nflags;
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struct stat st;
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
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return -EINVAL;
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if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
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return -errno;
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if (b)
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nflags = flags | BTRFS_SUBVOL_RDONLY;
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else
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nflags = flags & ~BTRFS_SUBVOL_RDONLY;
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if (flags == nflags)
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return 0;
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if (ioctl(fd, BTRFS_IOC_SUBVOL_SETFLAGS, &nflags) < 0)
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return -errno;
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return 0;
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}
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int btrfs_subvol_set_read_only(const char *path, bool b) {
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_cleanup_close_ int fd = -1;
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fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
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if (fd < 0)
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return -errno;
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return btrfs_subvol_set_read_only_fd(fd, b);
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}
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int btrfs_subvol_get_read_only_fd(int fd) {
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uint64_t flags;
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struct stat st;
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
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return -EINVAL;
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if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
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return -errno;
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return !!(flags & BTRFS_SUBVOL_RDONLY);
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}
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int btrfs_reflink(int infd, int outfd) {
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struct stat st;
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int r;
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assert(infd >= 0);
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assert(outfd >= 0);
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/* Make sure we invoke the ioctl on a regular file, so that no
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* device driver accidentally gets it. */
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if (fstat(outfd, &st) < 0)
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return -errno;
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if (!S_ISREG(st.st_mode))
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return -EINVAL;
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r = ioctl(outfd, BTRFS_IOC_CLONE, infd);
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if (r < 0)
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return -errno;
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return 0;
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}
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int btrfs_clone_range(int infd, uint64_t in_offset, int outfd, uint64_t out_offset, uint64_t sz) {
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struct btrfs_ioctl_clone_range_args args = {
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.src_fd = infd,
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.src_offset = in_offset,
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.src_length = sz,
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.dest_offset = out_offset,
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};
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struct stat st;
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int r;
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assert(infd >= 0);
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assert(outfd >= 0);
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assert(sz > 0);
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if (fstat(outfd, &st) < 0)
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return -errno;
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if (!S_ISREG(st.st_mode))
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return -EINVAL;
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r = ioctl(outfd, BTRFS_IOC_CLONE_RANGE, &args);
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if (r < 0)
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return -errno;
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return 0;
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}
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int btrfs_get_block_device_fd(int fd, dev_t *dev) {
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struct btrfs_ioctl_fs_info_args fsi = {};
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uint64_t id;
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int r;
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assert(fd >= 0);
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assert(dev);
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r = btrfs_is_filesystem(fd);
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if (r < 0)
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return r;
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if (!r)
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return -ENOTTY;
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if (ioctl(fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
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return -errno;
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/* We won't do this for btrfs RAID */
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if (fsi.num_devices != 1)
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return 0;
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for (id = 1; id <= fsi.max_id; id++) {
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struct btrfs_ioctl_dev_info_args di = {
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.devid = id,
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};
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struct stat st;
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if (ioctl(fd, BTRFS_IOC_DEV_INFO, &di) < 0) {
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if (errno == ENODEV)
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continue;
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return -errno;
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}
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if (stat((char*) di.path, &st) < 0)
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return -errno;
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if (!S_ISBLK(st.st_mode))
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return -ENODEV;
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if (major(st.st_rdev) == 0)
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return -ENODEV;
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*dev = st.st_rdev;
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return 1;
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}
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return -ENODEV;
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}
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int btrfs_get_block_device(const char *path, dev_t *dev) {
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_cleanup_close_ int fd = -1;
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assert(path);
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assert(dev);
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fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
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if (fd < 0)
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return -errno;
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return btrfs_get_block_device_fd(fd, dev);
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}
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int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
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struct btrfs_ioctl_ino_lookup_args args = {
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.objectid = BTRFS_FIRST_FREE_OBJECTID
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};
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int r;
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assert(fd >= 0);
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assert(ret);
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r = btrfs_is_filesystem(fd);
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if (r < 0)
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return r;
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if (!r)
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return -ENOTTY;
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if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args) < 0)
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return -errno;
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*ret = args.treeid;
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return 0;
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}
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static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) {
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assert(args);
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/* the objectid, type, offset together make up the btrfs key,
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* which is considered a single 136byte integer when
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* comparing. This call increases the counter by one, dealing
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* with the overflow between the overflows */
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if (args->key.min_offset < (uint64_t) -1) {
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args->key.min_offset++;
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return true;
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}
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if (args->key.min_type < (uint8_t) -1) {
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args->key.min_type++;
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args->key.min_offset = 0;
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return true;
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}
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if (args->key.min_objectid < (uint64_t) -1) {
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args->key.min_objectid++;
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args->key.min_offset = 0;
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args->key.min_type = 0;
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return true;
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}
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return 0;
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}
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static void btrfs_ioctl_search_args_set(struct btrfs_ioctl_search_args *args, const struct btrfs_ioctl_search_header *h) {
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assert(args);
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assert(h);
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args->key.min_objectid = h->objectid;
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args->key.min_type = h->type;
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args->key.min_offset = h->offset;
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}
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static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args *args) {
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assert(args);
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/* Compare min and max */
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if (args->key.min_objectid < args->key.max_objectid)
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return -1;
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if (args->key.min_objectid > args->key.max_objectid)
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return 1;
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if (args->key.min_type < args->key.max_type)
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return -1;
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if (args->key.min_type > args->key.max_type)
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return 1;
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if (args->key.min_offset < args->key.max_offset)
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return -1;
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if (args->key.min_offset > args->key.max_offset)
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return 1;
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return 0;
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}
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#define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) \
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for ((i) = 0, \
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(sh) = (const struct btrfs_ioctl_search_header*) (args).buf; \
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(i) < (args).key.nr_items; \
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(i)++, \
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(sh) = (const struct btrfs_ioctl_search_header*) ((uint8_t*) (sh) + sizeof(struct btrfs_ioctl_search_header) + (sh)->len))
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#define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh) \
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((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
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int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
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struct btrfs_ioctl_search_args args = {
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/* Tree of tree roots */
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.key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
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/* Look precisely for the subvolume items */
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.key.min_type = BTRFS_ROOT_ITEM_KEY,
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.key.max_type = BTRFS_ROOT_ITEM_KEY,
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.key.min_offset = 0,
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.key.max_offset = (uint64_t) -1,
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/* No restrictions on the other components */
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.key.min_transid = 0,
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.key.max_transid = (uint64_t) -1,
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};
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uint64_t subvol_id;
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bool found = false;
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int r;
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assert(fd >= 0);
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assert(ret);
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r = btrfs_subvol_get_id_fd(fd, &subvol_id);
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if (r < 0)
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return r;
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args.key.min_objectid = args.key.max_objectid = subvol_id;
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while (btrfs_ioctl_search_args_compare(&args) <= 0) {
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const struct btrfs_ioctl_search_header *sh;
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unsigned i;
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args.key.nr_items = 256;
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if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
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return -errno;
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if (args.key.nr_items <= 0)
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break;
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FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
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const struct btrfs_root_item *ri;
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/* Make sure we start the next search at least from this entry */
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btrfs_ioctl_search_args_set(&args, sh);
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if (sh->objectid != subvol_id)
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continue;
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if (sh->type != BTRFS_ROOT_ITEM_KEY)
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continue;
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/* Older versions of the struct lacked the otime setting */
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if (sh->len < offsetof(struct btrfs_root_item, otime) + sizeof(struct btrfs_timespec))
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continue;
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ri = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
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ret->otime = (usec_t) le64toh(ri->otime.sec) * USEC_PER_SEC +
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(usec_t) le32toh(ri->otime.nsec) / NSEC_PER_USEC;
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ret->subvol_id = subvol_id;
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ret->read_only = !!(le64toh(ri->flags) & BTRFS_ROOT_SUBVOL_RDONLY);
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assert_cc(sizeof(ri->uuid) == sizeof(ret->uuid));
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memcpy(&ret->uuid, ri->uuid, sizeof(ret->uuid));
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memcpy(&ret->parent_uuid, ri->parent_uuid, sizeof(ret->parent_uuid));
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found = true;
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goto finish;
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}
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/* Increase search key by one, to read the next item, if we can. */
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if (!btrfs_ioctl_search_args_inc(&args))
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break;
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}
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finish:
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if (!found)
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return -ENODATA;
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return 0;
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}
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int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
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struct btrfs_ioctl_search_args args = {
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/* Tree of quota items */
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.key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
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/* The object ID is always 0 */
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.key.min_objectid = 0,
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.key.max_objectid = 0,
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/* Look precisely for the quota items */
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.key.min_type = BTRFS_QGROUP_STATUS_KEY,
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.key.max_type = BTRFS_QGROUP_LIMIT_KEY,
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/* No restrictions on the other components */
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.key.min_transid = 0,
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.key.max_transid = (uint64_t) -1,
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};
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|
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uint64_t subvol_id;
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bool found_info = false, found_limit = false;
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int r;
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assert(fd >= 0);
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assert(ret);
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r = btrfs_subvol_get_id_fd(fd, &subvol_id);
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if (r < 0)
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return r;
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args.key.min_offset = args.key.max_offset = subvol_id;
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|
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while (btrfs_ioctl_search_args_compare(&args) <= 0) {
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const struct btrfs_ioctl_search_header *sh;
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unsigned i;
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|
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args.key.nr_items = 256;
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if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
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|
return -errno;
|
|
|
|
if (args.key.nr_items <= 0)
|
|
break;
|
|
|
|
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
|
|
|
|
/* Make sure we start the next search at least from this entry */
|
|
btrfs_ioctl_search_args_set(&args, sh);
|
|
|
|
if (sh->objectid != 0)
|
|
continue;
|
|
if (sh->offset != subvol_id)
|
|
continue;
|
|
|
|
if (sh->type == BTRFS_QGROUP_INFO_KEY) {
|
|
const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
|
|
|
|
ret->referenced = le64toh(qii->rfer);
|
|
ret->exclusive = le64toh(qii->excl);
|
|
|
|
found_info = true;
|
|
|
|
} else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
|
|
const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
|
|
|
|
ret->referenced_max = le64toh(qli->max_rfer);
|
|
ret->exclusive_max = le64toh(qli->max_excl);
|
|
|
|
if (ret->referenced_max == 0)
|
|
ret->referenced_max = (uint64_t) -1;
|
|
if (ret->exclusive_max == 0)
|
|
ret->exclusive_max = (uint64_t) -1;
|
|
|
|
found_limit = true;
|
|
}
|
|
|
|
if (found_info && found_limit)
|
|
goto finish;
|
|
}
|
|
|
|
/* Increase search key by one, to read the next item, if we can. */
|
|
if (!btrfs_ioctl_search_args_inc(&args))
|
|
break;
|
|
}
|
|
|
|
finish:
|
|
if (!found_limit && !found_info)
|
|
return -ENODATA;
|
|
|
|
if (!found_info) {
|
|
ret->referenced = (uint64_t) -1;
|
|
ret->exclusive = (uint64_t) -1;
|
|
}
|
|
|
|
if (!found_limit) {
|
|
ret->referenced_max = (uint64_t) -1;
|
|
ret->exclusive_max = (uint64_t) -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_defrag_fd(int fd) {
|
|
struct stat st;
|
|
|
|
assert(fd >= 0);
|
|
|
|
if (fstat(fd, &st) < 0)
|
|
return -errno;
|
|
|
|
if (!S_ISREG(st.st_mode))
|
|
return -EINVAL;
|
|
|
|
if (ioctl(fd, BTRFS_IOC_DEFRAG, NULL) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_defrag(const char *p) {
|
|
_cleanup_close_ int fd = -1;
|
|
|
|
fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
|
|
if (fd < 0)
|
|
return -errno;
|
|
|
|
return btrfs_defrag_fd(fd);
|
|
}
|
|
|
|
int btrfs_quota_enable_fd(int fd, bool b) {
|
|
struct btrfs_ioctl_quota_ctl_args args = {
|
|
.cmd = b ? BTRFS_QUOTA_CTL_ENABLE : BTRFS_QUOTA_CTL_DISABLE,
|
|
};
|
|
int r;
|
|
|
|
assert(fd >= 0);
|
|
|
|
r = btrfs_is_filesystem(fd);
|
|
if (r < 0)
|
|
return r;
|
|
if (!r)
|
|
return -ENOTTY;
|
|
|
|
if (ioctl(fd, BTRFS_IOC_QUOTA_CTL, &args) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_quota_enable(const char *path, bool b) {
|
|
_cleanup_close_ int fd = -1;
|
|
|
|
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
|
|
if (fd < 0)
|
|
return -errno;
|
|
|
|
return btrfs_quota_enable_fd(fd, b);
|
|
}
|
|
|
|
int btrfs_quota_limit_fd(int fd, uint64_t referenced_max) {
|
|
struct btrfs_ioctl_qgroup_limit_args args = {
|
|
.lim.max_rfer =
|
|
referenced_max == (uint64_t) -1 ? 0 :
|
|
referenced_max == 0 ? 1 : referenced_max,
|
|
.lim.flags = BTRFS_QGROUP_LIMIT_MAX_RFER,
|
|
};
|
|
int r;
|
|
|
|
assert(fd >= 0);
|
|
|
|
r = btrfs_is_filesystem(fd);
|
|
if (r < 0)
|
|
return r;
|
|
if (!r)
|
|
return -ENOTTY;
|
|
|
|
if (ioctl(fd, BTRFS_IOC_QGROUP_LIMIT, &args) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_quota_limit(const char *path, uint64_t referenced_max) {
|
|
_cleanup_close_ int fd = -1;
|
|
|
|
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
|
|
if (fd < 0)
|
|
return -errno;
|
|
|
|
return btrfs_quota_limit_fd(fd, referenced_max);
|
|
}
|
|
|
|
int btrfs_resize_loopback_fd(int fd, uint64_t new_size, bool grow_only) {
|
|
struct btrfs_ioctl_vol_args args = {};
|
|
_cleanup_free_ char *p = NULL, *loop = NULL, *backing = NULL;
|
|
_cleanup_close_ int loop_fd = -1, backing_fd = -1;
|
|
struct stat st;
|
|
dev_t dev = 0;
|
|
int r;
|
|
|
|
/* btrfs cannot handle file systems < 16M, hence use this as minimum */
|
|
if (new_size < 16*1024*1024)
|
|
new_size = 16*1024*1024;
|
|
|
|
r = btrfs_get_block_device_fd(fd, &dev);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
return -ENODEV;
|
|
|
|
if (asprintf(&p, "/sys/dev/block/%u:%u/loop/backing_file", major(dev), minor(dev)) < 0)
|
|
return -ENOMEM;
|
|
r = read_one_line_file(p, &backing);
|
|
if (r == -ENOENT)
|
|
return -ENODEV;
|
|
if (r < 0)
|
|
return r;
|
|
if (isempty(backing) || !path_is_absolute(backing))
|
|
return -ENODEV;
|
|
|
|
backing_fd = open(backing, O_RDWR|O_CLOEXEC|O_NOCTTY);
|
|
if (backing_fd < 0)
|
|
return -errno;
|
|
|
|
if (fstat(backing_fd, &st) < 0)
|
|
return -errno;
|
|
if (!S_ISREG(st.st_mode))
|
|
return -ENODEV;
|
|
|
|
if (new_size == (uint64_t) st.st_size)
|
|
return 0;
|
|
|
|
if (grow_only && new_size < (uint64_t) st.st_size)
|
|
return -EINVAL;
|
|
|
|
if (asprintf(&loop, "/dev/block/%u:%u", major(dev), minor(dev)) < 0)
|
|
return -ENOMEM;
|
|
loop_fd = open(loop, O_RDWR|O_CLOEXEC|O_NOCTTY);
|
|
if (loop_fd < 0)
|
|
return -errno;
|
|
|
|
if (snprintf(args.name, sizeof(args.name), "%" PRIu64, new_size) >= (int) sizeof(args.name))
|
|
return -EINVAL;
|
|
|
|
if (new_size < (uint64_t) st.st_size) {
|
|
/* Decrease size: first decrease btrfs size, then shorten loopback */
|
|
if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
|
|
return -errno;
|
|
}
|
|
|
|
if (ftruncate(backing_fd, new_size) < 0)
|
|
return -errno;
|
|
|
|
if (ioctl(loop_fd, LOOP_SET_CAPACITY, 0) < 0)
|
|
return -errno;
|
|
|
|
if (new_size > (uint64_t) st.st_size) {
|
|
/* Increase size: first enlarge loopback, then increase btrfs size */
|
|
if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
|
|
return -errno;
|
|
}
|
|
|
|
/* Make sure the free disk space is correctly updated for both file systems */
|
|
(void) fsync(fd);
|
|
(void) fsync(backing_fd);
|
|
|
|
return 1;
|
|
}
|
|
|
|
int btrfs_resize_loopback(const char *p, uint64_t new_size, bool grow_only) {
|
|
_cleanup_close_ int fd = -1;
|
|
|
|
fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC);
|
|
if (fd < 0)
|
|
return -errno;
|
|
|
|
return btrfs_resize_loopback_fd(fd, new_size, grow_only);
|
|
}
|
|
|
|
static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol_id, bool recursive) {
|
|
struct btrfs_ioctl_search_args args = {
|
|
.key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
|
|
|
|
.key.min_objectid = BTRFS_FIRST_FREE_OBJECTID,
|
|
.key.max_objectid = BTRFS_LAST_FREE_OBJECTID,
|
|
|
|
.key.min_type = BTRFS_ROOT_BACKREF_KEY,
|
|
.key.max_type = BTRFS_ROOT_BACKREF_KEY,
|
|
|
|
.key.min_transid = 0,
|
|
.key.max_transid = (uint64_t) -1,
|
|
};
|
|
|
|
struct btrfs_ioctl_vol_args vol_args = {};
|
|
_cleanup_close_ int subvol_fd = -1;
|
|
struct stat st;
|
|
bool made_writable = false;
|
|
int r;
|
|
|
|
assert(fd >= 0);
|
|
assert(subvolume);
|
|
|
|
if (fstat(fd, &st) < 0)
|
|
return -errno;
|
|
|
|
if (!S_ISDIR(st.st_mode))
|
|
return -EINVAL;
|
|
|
|
/* First, try to remove the subvolume. If it happens to be
|
|
* already empty, this will just work. */
|
|
strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
|
|
if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) >= 0)
|
|
return 0;
|
|
if (!recursive || errno != ENOTEMPTY)
|
|
return -errno;
|
|
|
|
/* OK, the subvolume is not empty, let's look for child
|
|
* subvolumes, and remove them, first */
|
|
subvol_fd = openat(fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (subvol_fd < 0)
|
|
return -errno;
|
|
|
|
if (subvol_id == 0) {
|
|
r = btrfs_subvol_get_id_fd(subvol_fd, &subvol_id);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
args.key.min_offset = args.key.max_offset = subvol_id;
|
|
|
|
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
|
|
const struct btrfs_ioctl_search_header *sh;
|
|
unsigned i;
|
|
|
|
args.key.nr_items = 256;
|
|
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
|
|
return -errno;
|
|
|
|
if (args.key.nr_items <= 0)
|
|
break;
|
|
|
|
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
|
|
_cleanup_free_ char *p = NULL;
|
|
const struct btrfs_root_ref *ref;
|
|
struct btrfs_ioctl_ino_lookup_args ino_args;
|
|
|
|
btrfs_ioctl_search_args_set(&args, sh);
|
|
|
|
if (sh->type != BTRFS_ROOT_BACKREF_KEY)
|
|
continue;
|
|
if (sh->offset != subvol_id)
|
|
continue;
|
|
|
|
ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
|
|
|
|
p = strndup((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
zero(ino_args);
|
|
ino_args.treeid = subvol_id;
|
|
ino_args.objectid = htole64(ref->dirid);
|
|
|
|
if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
|
|
return -errno;
|
|
|
|
if (!made_writable) {
|
|
r = btrfs_subvol_set_read_only_fd(subvol_fd, false);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
made_writable = true;
|
|
}
|
|
|
|
if (isempty(ino_args.name))
|
|
/* Subvolume is in the top-level
|
|
* directory of the subvolume. */
|
|
r = subvol_remove_children(subvol_fd, p, sh->objectid, recursive);
|
|
else {
|
|
_cleanup_close_ int child_fd = -1;
|
|
|
|
/* Subvolume is somewhere further down,
|
|
* hence we need to open the
|
|
* containing directory first */
|
|
|
|
child_fd = openat(subvol_fd, ino_args.name, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (child_fd < 0)
|
|
return -errno;
|
|
|
|
r = subvol_remove_children(child_fd, p, sh->objectid, recursive);
|
|
}
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
/* Increase search key by one, to read the next item, if we can. */
|
|
if (!btrfs_ioctl_search_args_inc(&args))
|
|
break;
|
|
}
|
|
|
|
/* OK, the child subvolumes should all be gone now, let's try
|
|
* again to remove the subvolume */
|
|
if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_subvol_remove(const char *path, bool recursive) {
|
|
_cleanup_close_ int fd = -1;
|
|
const char *subvolume;
|
|
int r;
|
|
|
|
assert(path);
|
|
|
|
r = extract_subvolume_name(path, &subvolume);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (fd < 0)
|
|
return fd;
|
|
|
|
return subvol_remove_children(fd, subvolume, 0, recursive);
|
|
}
|
|
|
|
int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive) {
|
|
return subvol_remove_children(fd, subvolume, 0, recursive);
|
|
}
|
|
|
|
static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolume, uint64_t subvol_id, BtrfsSnapshotFlags flags) {
|
|
|
|
struct btrfs_ioctl_search_args args = {
|
|
.key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
|
|
|
|
.key.min_objectid = BTRFS_FIRST_FREE_OBJECTID,
|
|
.key.max_objectid = BTRFS_LAST_FREE_OBJECTID,
|
|
|
|
.key.min_type = BTRFS_ROOT_BACKREF_KEY,
|
|
.key.max_type = BTRFS_ROOT_BACKREF_KEY,
|
|
|
|
.key.min_transid = 0,
|
|
.key.max_transid = (uint64_t) -1,
|
|
};
|
|
|
|
struct btrfs_ioctl_vol_args_v2 vol_args = {
|
|
.flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0,
|
|
.fd = old_fd,
|
|
};
|
|
int r;
|
|
_cleanup_close_ int subvolume_fd = -1;
|
|
|
|
assert(old_fd >= 0);
|
|
assert(new_fd >= 0);
|
|
assert(subvolume);
|
|
|
|
strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
|
|
vol_args.fd = old_fd;
|
|
|
|
if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &vol_args) < 0)
|
|
return -errno;
|
|
|
|
if (!(flags & BTRFS_SNAPSHOT_RECURSIVE))
|
|
return 0;
|
|
|
|
if (subvol_id == 0) {
|
|
r = btrfs_subvol_get_id_fd(old_fd, &subvol_id);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
args.key.min_offset = args.key.max_offset = subvol_id;
|
|
|
|
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
|
|
const struct btrfs_ioctl_search_header *sh;
|
|
unsigned i;
|
|
|
|
args.key.nr_items = 256;
|
|
if (ioctl(old_fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
|
|
return -errno;
|
|
|
|
if (args.key.nr_items <= 0)
|
|
break;
|
|
|
|
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
|
|
_cleanup_free_ char *p = NULL, *c = NULL, *np = NULL;
|
|
struct btrfs_ioctl_ino_lookup_args ino_args;
|
|
const struct btrfs_root_ref *ref;
|
|
_cleanup_close_ int old_child_fd = -1, new_child_fd = -1;
|
|
|
|
btrfs_ioctl_search_args_set(&args, sh);
|
|
|
|
if (sh->type != BTRFS_ROOT_BACKREF_KEY)
|
|
continue;
|
|
if (sh->offset != subvol_id)
|
|
continue;
|
|
|
|
ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
|
|
|
|
p = strndup((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
zero(ino_args);
|
|
ino_args.treeid = subvol_id;
|
|
ino_args.objectid = htole64(ref->dirid);
|
|
|
|
if (ioctl(old_fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
|
|
return -errno;
|
|
|
|
/* The kernel returns an empty name if the
|
|
* subvolume is in the top-level directory,
|
|
* and otherwise appends a slash, so that we
|
|
* can just concatenate easily here, without
|
|
* adding a slash. */
|
|
c = strappend(ino_args.name, p);
|
|
if (!c)
|
|
return -ENOMEM;
|
|
|
|
old_child_fd = openat(old_fd, c, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (old_child_fd < 0)
|
|
return -errno;
|
|
|
|
np = strjoin(subvolume, "/", ino_args.name, NULL);
|
|
if (!np)
|
|
return -ENOMEM;
|
|
|
|
new_child_fd = openat(new_fd, np, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (new_child_fd < 0)
|
|
return -errno;
|
|
|
|
if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
|
|
/* If the snapshot is read-only we
|
|
* need to mark it writable
|
|
* temporarily, to put the subsnapshot
|
|
* into place. */
|
|
|
|
if (subvolume_fd < 0) {
|
|
subvolume_fd = openat(new_fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (subvolume_fd < 0)
|
|
return -errno;
|
|
}
|
|
|
|
r = btrfs_subvol_set_read_only_fd(subvolume_fd, false);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
/* When btrfs clones the subvolumes, child
|
|
* subvolumes appear as directories. Remove
|
|
* them, so that we can create a new snapshot
|
|
* in their place */
|
|
if (unlinkat(new_child_fd, p, AT_REMOVEDIR) < 0) {
|
|
int k = -errno;
|
|
|
|
if (flags & BTRFS_SNAPSHOT_READ_ONLY)
|
|
(void) btrfs_subvol_set_read_only_fd(subvolume_fd, true);
|
|
|
|
return k;
|
|
}
|
|
|
|
r = subvol_snapshot_children(old_child_fd, new_child_fd, p, sh->objectid, flags & ~BTRFS_SNAPSHOT_FALLBACK_COPY);
|
|
|
|
/* Restore the readonly flag */
|
|
if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
|
|
int k;
|
|
|
|
k = btrfs_subvol_set_read_only_fd(subvolume_fd, true);
|
|
if (r >= 0 && k < 0)
|
|
return k;
|
|
}
|
|
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
/* Increase search key by one, to read the next item, if we can. */
|
|
if (!btrfs_ioctl_search_args_inc(&args))
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlags flags) {
|
|
_cleanup_close_ int new_fd = -1;
|
|
const char *subvolume;
|
|
int r;
|
|
|
|
assert(old_fd >= 0);
|
|
assert(new_path);
|
|
|
|
r = btrfs_is_subvol(old_fd);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0) {
|
|
if (!(flags & BTRFS_SNAPSHOT_FALLBACK_COPY))
|
|
return -EISDIR;
|
|
|
|
r = btrfs_subvol_make(new_path);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = copy_directory_fd(old_fd, new_path, true);
|
|
if (r < 0) {
|
|
btrfs_subvol_remove(new_path, false);
|
|
return r;
|
|
}
|
|
|
|
if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
|
|
r = btrfs_subvol_set_read_only(new_path, true);
|
|
if (r < 0) {
|
|
btrfs_subvol_remove(new_path, false);
|
|
return r;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
r = extract_subvolume_name(new_path, &subvolume);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (new_fd < 0)
|
|
return new_fd;
|
|
|
|
return subvol_snapshot_children(old_fd, new_fd, subvolume, 0, flags);
|
|
}
|
|
|
|
int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnapshotFlags flags) {
|
|
_cleanup_close_ int old_fd = -1;
|
|
|
|
assert(old_path);
|
|
assert(new_path);
|
|
|
|
old_fd = open(old_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
|
|
if (old_fd < 0)
|
|
return -errno;
|
|
|
|
return btrfs_subvol_snapshot_fd(old_fd, new_path, flags);
|
|
}
|