1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2015 Lennart Poettering
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 #include <linux/loop.h>
29 #include <sys/ioctl.h>
30 #include <sys/mount.h>
31 #include <sys/prctl.h>
33 #include <sys/statfs.h>
34 #include <sys/statvfs.h>
37 #include "sd-bus-protocol.h"
40 #include "alloc-util.h"
41 #include "btrfs-util.h"
46 #include "lockfile-util.h"
48 #include "machine-pool.h"
52 #include "mount-util.h"
53 #include "parse-util.h"
54 #include "path-util.h"
55 #include "process-util.h"
56 #include "signal-util.h"
57 #include "stat-util.h"
58 #include "string-util.h"
60 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
61 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
63 static int check_btrfs(void) {
66 if (statfs("/var/lib/machines", &sfs
) < 0) {
70 if (statfs("/var/lib", &sfs
) < 0)
74 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
77 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
78 _cleanup_free_
char *tmp
= NULL
;
79 _cleanup_close_
int fd
= -1;
84 /* We want to be able to make use of btrfs-specific file
85 * system features, in particular subvolumes, reflinks and
86 * quota. Hence, if we detect that /var/lib/machines.raw is
87 * not located on btrfs, let's create a loopback file, place a
88 * btrfs file system into it, and mount it to
89 * /var/lib/machines. */
91 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
96 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
98 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
102 (void) mkdir_p_label("/var/lib", 0755);
103 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
105 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
107 if (fstatvfs(fd
, &ss
) < 0) {
108 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
112 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
113 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
117 if (ftruncate(fd
, size
) < 0) {
118 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
122 r
= safe_fork("(mkfs)", FORK_RESET_SIGNALS
|FORK_DEATHSIG
, &pid
);
124 sd_bus_error_set_errnof(error
, r
, "Failed to fork mkfs.btrfs: %m");
133 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
140 r
= wait_for_terminate_and_check("mkfs", pid
, 0);
144 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
148 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
151 if (r
!= EXIT_SUCCESS
) {
152 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", r
);
156 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
158 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
168 kill_and_sigcont(pid
, SIGKILL
);
173 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
174 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
175 struct loop_info64 info
= {
176 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
178 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
179 _cleanup_free_
char* loopdev
= NULL
;
180 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
181 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
182 char buf
[FORMAT_BYTES_MAX
];
185 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
186 if (size
== (uint64_t) -1)
187 size
= VAR_LIB_MACHINES_SIZE_START
;
188 else if (size
< 16*1024*1024)
191 /* Make sure we only set the directory up once at a time */
192 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
198 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
200 (void) btrfs_subvol_make_label("/var/lib/machines");
202 r
= btrfs_quota_enable("/var/lib/machines", true);
204 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
206 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
208 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
213 if (path_is_mount_point("/var/lib/machines", NULL
, AT_SYMLINK_FOLLOW
) > 0) {
214 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
218 r
= dir_is_populated("/var/lib/machines");
219 if (r
< 0 && r
!= -ENOENT
)
222 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
226 r
= mkfs_exists("btrfs");
228 return sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
232 fd
= setup_machine_raw(size
, error
);
236 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
238 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
240 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
242 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
244 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
249 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
251 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
255 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
256 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
260 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
261 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
265 /* We need to make sure the new /var/lib/machines directory
266 * has an access mode of 0700 at the time it is first made
267 * available. mkfs will create it with 0755 however. Hence,
268 * let's mount the directory into an inaccessible directory
269 * below /tmp first, fix the access mode, and move it to the
270 * public place then. */
272 if (!mkdtemp(tmpdir
)) {
273 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
278 mntdir
= strjoina(tmpdir
, "/mnt");
279 if (mkdir(mntdir
, 0700) < 0) {
280 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
285 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
286 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
289 mntdir_mounted
= true;
291 r
= btrfs_quota_enable(mntdir
, true);
293 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
295 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
297 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
299 if (chmod(mntdir
, 0700) < 0) {
300 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
304 (void) mkdir_p_label("/var/lib/machines", 0700);
306 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
307 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
313 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
));
315 (void) umount2(mntdir
, MNT_DETACH
);
316 (void) rmdir(mntdir
);
317 (void) rmdir(tmpdir
);
323 (void) umount2(mntdir
, MNT_DETACH
);
326 (void) rmdir(mntdir
);
328 (void) rmdir(tmpdir
);
331 (void) ioctl(loop
, LOOP_CLR_FD
);
332 loop
= safe_close(loop
);
335 if (control
>= 0 && nr
>= 0)
336 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
341 static int sync_path(const char *p
) {
342 _cleanup_close_
int fd
= -1;
344 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
354 int grow_machine_directory(void) {
355 char buf
[FORMAT_BYTES_MAX
];
357 uint64_t old_size
, new_size
, max_add
;
360 /* Ensure the disk space data is accurate */
361 sync_path("/var/lib/machines");
362 sync_path("/var/lib/machines.raw");
364 if (statvfs("/var/lib/machines.raw", &a
) < 0)
367 if (statvfs("/var/lib/machines", &b
) < 0)
370 /* Don't grow if not enough disk space is available on the host */
371 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
374 /* Don't grow if at least 1/3th of the fs is still free */
375 if (b
.f_bavail
> b
.f_blocks
/ 3)
378 /* Calculate how much we are willing to add at most */
379 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
381 /* Calculate the old size */
382 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
384 /* Calculate the new size as three times the size of what is used right now */
385 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
387 /* Always, grow at least to the start size */
388 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
389 new_size
= VAR_LIB_MACHINES_SIZE_START
;
391 /* If the new size is smaller than the old size, don't grow */
392 if (new_size
< old_size
)
395 /* Ensure we never add more than the maximum */
396 if (new_size
> old_size
+ max_add
)
397 new_size
= old_size
+ max_add
;
399 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
403 /* Also bump the quota, of both the subvolume leaf qgroup, as
404 * well as of any subtree quota group by the same id but a
405 * higher level, if it exists. */
406 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
407 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
409 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));