1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2015 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <sys/prctl.h>
24 #include <sys/statvfs.h>
25 #include <sys/mount.h>
29 #include "btrfs-util.h"
30 #include "path-util.h"
31 #include "machine-pool.h"
33 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
34 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
36 static int check_btrfs(void) {
39 if (statfs("/var/lib/machines", &sfs) < 0) {
43 if (statfs("/var/lib", &sfs) < 0)
47 return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
50 static int setup_machine_raw(uint64_t size, sd_bus_error *error) {
51 _cleanup_free_ char *tmp = NULL;
52 _cleanup_close_ int fd = -1;
58 /* We want to be able to make use of btrfs-specific file
59 * system features, in particular subvolumes, reflinks and
60 * quota. Hence, if we detect that /var/lib/machines.raw is
61 * not located on btrfs, let's create a loopback file, place a
62 * btrfs file system into it, and mount it to
63 * /var/lib/machines. */
65 fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
73 return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");
75 r = tempfn_xxxxxx("/var/lib/machines.raw", &tmp);
79 (void) mkdir_p_label("/var/lib", 0755);
80 fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600);
82 return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");
84 if (fstatvfs(fd, &ss) < 0) {
85 r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
89 if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
90 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
94 if (ftruncate(fd, size) < 0) {
95 r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
101 r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
109 reset_all_signal_handlers();
111 assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
115 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
122 r = wait_for_terminate(pid, &si);
124 sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
130 if (si.si_code != CLD_EXITED) {
131 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
134 if (si.si_status == 99) {
135 r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
138 if (si.si_status != 0) {
139 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
143 r = rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw");
145 sd_bus_error_set_errnof(error, r, "Failed to move /var/lib/machines.raw into place: %m");
158 kill_and_sigcont(pid, SIGKILL);
163 int setup_machine_directory(uint64_t size, sd_bus_error *error) {
164 _cleanup_release_lock_file_ LockFile lock_file = LOCK_FILE_INIT;
165 struct loop_info64 info = {
166 .lo_flags = LO_FLAGS_AUTOCLEAR,
168 _cleanup_close_ int fd = -1, control = -1, loop = -1;
169 _cleanup_free_ char* loopdev = NULL;
170 char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
171 bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
172 char buf[FORMAT_BYTES_MAX];
175 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
176 if (size == (uint64_t) -1)
177 size = VAR_LIB_MACHINES_SIZE_START;
178 else if (size < 16*1024*1024)
181 /* Make sure we only set the directory up once at a time */
182 r = make_lock_file("/run/systemd/machines.lock", LOCK_EX, &lock_file);
188 return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
190 (void) btrfs_subvol_make_label("/var/lib/machines");
192 r = btrfs_quota_enable("/var/lib/machines", true);
194 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
199 if (path_is_mount_point("/var/lib/machines", true) > 0 ||
200 dir_is_empty("/var/lib/machines") == 0)
201 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "/var/lib/machines is not a btrfs file system. Operation is not supported on legacy file systems.");
203 fd = setup_machine_raw(size, error);
207 control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
209 return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m");
211 nr = ioctl(control, LOOP_CTL_GET_FREE);
213 return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m");
215 if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) {
220 loop = open(loopdev, O_CLOEXEC|O_RDWR|O_NOCTTY|O_NONBLOCK);
222 r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m");
226 if (ioctl(loop, LOOP_SET_FD, fd) < 0) {
227 r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m");
231 if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) {
232 r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m");
236 /* We need to make sure the new /var/lib/machines directory
237 * has an access mode of 0700 at the time it is first made
238 * available. mkfs will create it with 0755 however. Hence,
239 * let's mount the directory into an inaccessible directory
240 * below /tmp first, fix the access mode, and move it to the
241 * public place then. */
243 if (!mkdtemp(tmpdir)) {
244 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m");
249 mntdir = strjoina(tmpdir, "/mnt");
250 if (mkdir(mntdir, 0700) < 0) {
251 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m");
256 if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) {
257 r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m");
260 mntdir_mounted = true;
262 r = btrfs_quota_enable(mntdir, true);
264 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
266 if (chmod(mntdir, 0700) < 0) {
267 r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m");
271 (void) mkdir_p_label("/var/lib/machines", 0700);
273 if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) {
274 r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m");
280 log_info("Set up /var/lib/machines as btrfs loopback file system of size %s mounted on /var/lib/machines.raw.", format_bytes(buf, sizeof(buf), size));
282 (void) umount2(mntdir, MNT_DETACH);
283 (void) rmdir(mntdir);
284 (void) rmdir(tmpdir);
290 (void) umount2(mntdir, MNT_DETACH);
293 (void) rmdir(mntdir);
295 (void) rmdir(tmpdir);
298 (void) ioctl(loop, LOOP_CLR_FD);
299 loop = safe_close(loop);
302 if (control >= 0 && nr >= 0)
303 (void) ioctl(control, LOOP_CTL_REMOVE, nr);
308 static int sync_path(const char *p) {
309 _cleanup_close_ int fd = -1;
311 fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
321 int grow_machine_directory(void) {
322 char buf[FORMAT_BYTES_MAX];
324 uint64_t old_size, new_size, max_add;
327 /* Ensure the disk space data is accurate */
328 sync_path("/var/lib/machines");
329 sync_path("/var/lib/machines.raw");
331 if (statvfs("/var/lib/machines.raw", &a) < 0)
334 if (statvfs("/var/lib/machines", &b) < 0)
337 /* Don't grow if not enough disk space is available on the host */
338 if (((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) <= VAR_LIB_MACHINES_FREE_MIN)
341 /* Don't grow if at least 1/3th of the fs is still free */
342 if (b.f_bavail > b.f_blocks / 3)
345 /* Calculate how much we are willing to add at maximum */
346 max_add = ((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) - VAR_LIB_MACHINES_FREE_MIN;
348 /* Calculate the old size */
349 old_size = (uint64_t) b.f_blocks * (uint64_t) b.f_bsize;
351 /* Calculate the new size as three times the size of what is used right now */
352 new_size = ((uint64_t) b.f_blocks - (uint64_t) b.f_bavail) * (uint64_t) b.f_bsize * 3;
354 /* Always, grow at least to the start size */
355 if (new_size < VAR_LIB_MACHINES_SIZE_START)
356 new_size = VAR_LIB_MACHINES_SIZE_START;
358 /* If the new size is smaller than the old size, don't grow */
359 if (new_size < old_size)
362 /* Ensure we never add more than the maximum */
363 if (new_size > old_size + max_add)
364 new_size = old_size + max_add;
366 r = btrfs_resize_loopback("/var/lib/machines", new_size, true);
370 r = btrfs_quota_limit("/var/lib/machines", new_size);
374 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf, sizeof(buf), new_size));