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"
29 #include "lockfile-util.h"
31 #include "btrfs-util.h"
32 #include "path-util.h"
33 #include "signal-util.h"
34 #include "machine-pool.h"
36 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
37 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
39 static int check_btrfs(void) {
42 if (statfs("/var/lib/machines", &sfs) < 0) {
46 if (statfs("/var/lib", &sfs) < 0)
50 return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
53 static int setup_machine_raw(uint64_t size, sd_bus_error *error) {
54 _cleanup_free_ char *tmp = NULL;
55 _cleanup_close_ int fd = -1;
61 /* We want to be able to make use of btrfs-specific file
62 * system features, in particular subvolumes, reflinks and
63 * quota. Hence, if we detect that /var/lib/machines.raw is
64 * not located on btrfs, let's create a loopback file, place a
65 * btrfs file system into it, and mount it to
66 * /var/lib/machines. */
68 fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
76 return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");
78 r = tempfn_xxxxxx("/var/lib/machines.raw", NULL, &tmp);
82 (void) mkdir_p_label("/var/lib", 0755);
83 fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600);
85 return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");
87 if (fstatvfs(fd, &ss) < 0) {
88 r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
92 if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
93 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
97 if (ftruncate(fd, size) < 0) {
98 r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
104 r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
112 (void) reset_all_signal_handlers();
113 (void) reset_signal_mask();
114 assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
118 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
125 r = wait_for_terminate(pid, &si);
127 sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
133 if (si.si_code != CLD_EXITED) {
134 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
137 if (si.si_status == 99) {
138 r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
141 if (si.si_status != 0) {
142 r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
146 r = rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw");
148 sd_bus_error_set_errnof(error, r, "Failed to move /var/lib/machines.raw into place: %m");
161 kill_and_sigcont(pid, SIGKILL);
166 int setup_machine_directory(uint64_t size, sd_bus_error *error) {
167 _cleanup_release_lock_file_ LockFile lock_file = LOCK_FILE_INIT;
168 struct loop_info64 info = {
169 .lo_flags = LO_FLAGS_AUTOCLEAR,
171 _cleanup_close_ int fd = -1, control = -1, loop = -1;
172 _cleanup_free_ char* loopdev = NULL;
173 char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
174 bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
175 char buf[FORMAT_BYTES_MAX];
178 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
179 if (size == (uint64_t) -1)
180 size = VAR_LIB_MACHINES_SIZE_START;
181 else if (size < 16*1024*1024)
184 /* Make sure we only set the directory up once at a time */
185 r = make_lock_file("/run/systemd/machines.lock", LOCK_EX, &lock_file);
191 return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
193 (void) btrfs_subvol_make_label("/var/lib/machines");
195 r = btrfs_quota_enable("/var/lib/machines", true);
197 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
202 if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW) > 0 ||
203 dir_is_empty("/var/lib/machines") == 0)
204 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.");
206 fd = setup_machine_raw(size, error);
210 control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
212 return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m");
214 nr = ioctl(control, LOOP_CTL_GET_FREE);
216 return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m");
218 if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) {
223 loop = open(loopdev, O_CLOEXEC|O_RDWR|O_NOCTTY|O_NONBLOCK);
225 r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m");
229 if (ioctl(loop, LOOP_SET_FD, fd) < 0) {
230 r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m");
234 if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) {
235 r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m");
239 /* We need to make sure the new /var/lib/machines directory
240 * has an access mode of 0700 at the time it is first made
241 * available. mkfs will create it with 0755 however. Hence,
242 * let's mount the directory into an inaccessible directory
243 * below /tmp first, fix the access mode, and move it to the
244 * public place then. */
246 if (!mkdtemp(tmpdir)) {
247 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m");
252 mntdir = strjoina(tmpdir, "/mnt");
253 if (mkdir(mntdir, 0700) < 0) {
254 r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m");
259 if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) {
260 r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m");
263 mntdir_mounted = true;
265 r = btrfs_quota_enable(mntdir, true);
267 log_warning_errno(r, "Failed to enable quota, ignoring: %m");
269 if (chmod(mntdir, 0700) < 0) {
270 r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m");
274 (void) mkdir_p_label("/var/lib/machines", 0700);
276 if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) {
277 r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m");
283 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));
285 (void) umount2(mntdir, MNT_DETACH);
286 (void) rmdir(mntdir);
287 (void) rmdir(tmpdir);
293 (void) umount2(mntdir, MNT_DETACH);
296 (void) rmdir(mntdir);
298 (void) rmdir(tmpdir);
301 (void) ioctl(loop, LOOP_CLR_FD);
302 loop = safe_close(loop);
305 if (control >= 0 && nr >= 0)
306 (void) ioctl(control, LOOP_CTL_REMOVE, nr);
311 static int sync_path(const char *p) {
312 _cleanup_close_ int fd = -1;
314 fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
324 int grow_machine_directory(void) {
325 char buf[FORMAT_BYTES_MAX];
327 uint64_t old_size, new_size, max_add;
330 /* Ensure the disk space data is accurate */
331 sync_path("/var/lib/machines");
332 sync_path("/var/lib/machines.raw");
334 if (statvfs("/var/lib/machines.raw", &a) < 0)
337 if (statvfs("/var/lib/machines", &b) < 0)
340 /* Don't grow if not enough disk space is available on the host */
341 if (((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) <= VAR_LIB_MACHINES_FREE_MIN)
344 /* Don't grow if at least 1/3th of the fs is still free */
345 if (b.f_bavail > b.f_blocks / 3)
348 /* Calculate how much we are willing to add at maximum */
349 max_add = ((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) - VAR_LIB_MACHINES_FREE_MIN;
351 /* Calculate the old size */
352 old_size = (uint64_t) b.f_blocks * (uint64_t) b.f_bsize;
354 /* Calculate the new size as three times the size of what is used right now */
355 new_size = ((uint64_t) b.f_blocks - (uint64_t) b.f_bavail) * (uint64_t) b.f_bsize * 3;
357 /* Always, grow at least to the start size */
358 if (new_size < VAR_LIB_MACHINES_SIZE_START)
359 new_size = VAR_LIB_MACHINES_SIZE_START;
361 /* If the new size is smaller than the old size, don't grow */
362 if (new_size < old_size)
365 /* Ensure we never add more than the maximum */
366 if (new_size > old_size + max_add)
367 new_size = old_size + max_add;
369 r = btrfs_resize_loopback("/var/lib/machines", new_size, true);
373 r = btrfs_quota_limit("/var/lib/machines", new_size);
377 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf, sizeof(buf), new_size));