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>
28 #include "process-util.h"
30 #include "btrfs-util.h"
31 #include "path-util.h"
32 #include "machine-pool.h"
34 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
35 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
37 static int check_btrfs(void) {
40 if (statfs("/var/lib/machines", &sfs) < 0) {
44 if (statfs("/var/lib", &sfs) < 0)
48 return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
51 static int setup_machine_raw(uint64_t size, sd_bus_error *error) {
52 _cleanup_free_ char *tmp = NULL;
53 _cleanup_close_ int fd = -1;
59 /* We want to be able to make use of btrfs-specific file
60 * system features, in particular subvolumes, reflinks and
61 * quota. Hence, if we detect that /var/lib/machines.raw is
62 * not located on btrfs, let's create a loopback file, place a
63 * btrfs file system into it, and mount it to
64 * /var/lib/machines. */
66 fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
74 return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");
76 r = tempfn_xxxxxx("/var/lib/machines.raw", &tmp);
80 (void) mkdir_p_label("/var/lib", 0755);
81 fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600);
83 return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");
85 if (fstatvfs(fd, &ss) < 0) {
86 r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
90 if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
91 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
95 if (ftruncate(fd, size) < 0) {
96 r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
102 r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
110 reset_all_signal_handlers();
112 assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
116 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
123 r = wait_for_terminate(pid, &si);
125 sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
131 if (si.si_code != CLD_EXITED) {
132 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
135 if (si.si_status == 99) {
136 r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
139 if (si.si_status != 0) {
140 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
144 r = rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw");
146 sd_bus_error_set_errnof(error, r, "Failed to move /var/lib/machines.raw into place: %m");
159 kill_and_sigcont(pid, SIGKILL);
164 int setup_machine_directory(uint64_t size, sd_bus_error *error) {
165 _cleanup_release_lock_file_ LockFile lock_file = LOCK_FILE_INIT;
166 struct loop_info64 info = {
167 .lo_flags = LO_FLAGS_AUTOCLEAR,
169 _cleanup_close_ int fd = -1, control = -1, loop = -1;
170 _cleanup_free_ char* loopdev = NULL;
171 char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
172 bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
173 char buf[FORMAT_BYTES_MAX];
176 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
177 if (size == (uint64_t) -1)
178 size = VAR_LIB_MACHINES_SIZE_START;
179 else if (size < 16*1024*1024)
182 /* Make sure we only set the directory up once at a time */
183 r = make_lock_file("/run/systemd/machines.lock", LOCK_EX, &lock_file);
189 return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
191 (void) btrfs_subvol_make_label("/var/lib/machines");
193 r = btrfs_quota_enable("/var/lib/machines", true);
195 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
200 if (path_is_mount_point("/var/lib/machines", true) > 0 ||
201 dir_is_empty("/var/lib/machines") == 0)
202 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.");
204 fd = setup_machine_raw(size, error);
208 control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
210 return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m");
212 nr = ioctl(control, LOOP_CTL_GET_FREE);
214 return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m");
216 if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) {
221 loop = open(loopdev, O_CLOEXEC|O_RDWR|O_NOCTTY|O_NONBLOCK);
223 r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m");
227 if (ioctl(loop, LOOP_SET_FD, fd) < 0) {
228 r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m");
232 if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) {
233 r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m");
237 /* We need to make sure the new /var/lib/machines directory
238 * has an access mode of 0700 at the time it is first made
239 * available. mkfs will create it with 0755 however. Hence,
240 * let's mount the directory into an inaccessible directory
241 * below /tmp first, fix the access mode, and move it to the
242 * public place then. */
244 if (!mkdtemp(tmpdir)) {
245 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m");
250 mntdir = strjoina(tmpdir, "/mnt");
251 if (mkdir(mntdir, 0700) < 0) {
252 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m");
257 if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) {
258 r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m");
261 mntdir_mounted = true;
263 r = btrfs_quota_enable(mntdir, true);
265 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
267 if (chmod(mntdir, 0700) < 0) {
268 r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m");
272 (void) mkdir_p_label("/var/lib/machines", 0700);
274 if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) {
275 r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m");
281 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));
283 (void) umount2(mntdir, MNT_DETACH);
284 (void) rmdir(mntdir);
285 (void) rmdir(tmpdir);
291 (void) umount2(mntdir, MNT_DETACH);
294 (void) rmdir(mntdir);
296 (void) rmdir(tmpdir);
299 (void) ioctl(loop, LOOP_CLR_FD);
300 loop = safe_close(loop);
303 if (control >= 0 && nr >= 0)
304 (void) ioctl(control, LOOP_CTL_REMOVE, nr);
309 static int sync_path(const char *p) {
310 _cleanup_close_ int fd = -1;
312 fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
322 int grow_machine_directory(void) {
323 char buf[FORMAT_BYTES_MAX];
325 uint64_t old_size, new_size, max_add;
328 /* Ensure the disk space data is accurate */
329 sync_path("/var/lib/machines");
330 sync_path("/var/lib/machines.raw");
332 if (statvfs("/var/lib/machines.raw", &a) < 0)
335 if (statvfs("/var/lib/machines", &b) < 0)
338 /* Don't grow if not enough disk space is available on the host */
339 if (((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) <= VAR_LIB_MACHINES_FREE_MIN)
342 /* Don't grow if at least 1/3th of the fs is still free */
343 if (b.f_bavail > b.f_blocks / 3)
346 /* Calculate how much we are willing to add at maximum */
347 max_add = ((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) - VAR_LIB_MACHINES_FREE_MIN;
349 /* Calculate the old size */
350 old_size = (uint64_t) b.f_blocks * (uint64_t) b.f_bsize;
352 /* Calculate the new size as three times the size of what is used right now */
353 new_size = ((uint64_t) b.f_blocks - (uint64_t) b.f_bavail) * (uint64_t) b.f_bsize * 3;
355 /* Always, grow at least to the start size */
356 if (new_size < VAR_LIB_MACHINES_SIZE_START)
357 new_size = VAR_LIB_MACHINES_SIZE_START;
359 /* If the new size is smaller than the old size, don't grow */
360 if (new_size < old_size)
363 /* Ensure we never add more than the maximum */
364 if (new_size > old_size + max_add)
365 new_size = old_size + max_add;
367 r = btrfs_resize_loopback("/var/lib/machines", new_size, true);
371 r = btrfs_quota_limit("/var/lib/machines", new_size);
375 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf, sizeof(buf), new_size));