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
);
99 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
101 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
105 (void) mkdir_p_label("/var/lib", 0755);
106 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
108 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
110 if (fstatvfs(fd
, &ss
) < 0) {
111 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
115 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
116 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
120 if (ftruncate(fd
, size
) < 0) {
121 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
125 r
= safe_fork("(mkfs)", FORK_RESET_SIGNALS
|FORK_DEATHSIG
, &pid
);
127 sd_bus_error_set_errnof(error
, r
, "Failed to fork mkfs.btrfs: %m");
136 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
143 r
= wait_for_terminate_and_check("mkfs", pid
, 0);
147 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
151 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
154 if (r
!= EXIT_SUCCESS
) {
155 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", r
);
159 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
161 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
174 kill_and_sigcont(pid
, SIGKILL
);
179 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
180 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
181 struct loop_info64 info
= {
182 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
184 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
185 _cleanup_free_
char* loopdev
= NULL
;
186 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
187 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
188 char buf
[FORMAT_BYTES_MAX
];
191 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
192 if (size
== (uint64_t) -1)
193 size
= VAR_LIB_MACHINES_SIZE_START
;
194 else if (size
< 16*1024*1024)
197 /* Make sure we only set the directory up once at a time */
198 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
204 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
206 (void) btrfs_subvol_make_label("/var/lib/machines");
208 r
= btrfs_quota_enable("/var/lib/machines", true);
210 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
212 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
214 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
219 if (path_is_mount_point("/var/lib/machines", NULL
, AT_SYMLINK_FOLLOW
) > 0) {
220 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
224 r
= dir_is_populated("/var/lib/machines");
225 if (r
< 0 && r
!= -ENOENT
)
228 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
232 r
= mkfs_exists("btrfs");
234 return sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
238 fd
= setup_machine_raw(size
, error
);
242 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
244 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
246 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
248 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
250 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
255 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
257 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
261 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
262 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
266 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
267 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
271 /* We need to make sure the new /var/lib/machines directory
272 * has an access mode of 0700 at the time it is first made
273 * available. mkfs will create it with 0755 however. Hence,
274 * let's mount the directory into an inaccessible directory
275 * below /tmp first, fix the access mode, and move it to the
276 * public place then. */
278 if (!mkdtemp(tmpdir
)) {
279 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
284 mntdir
= strjoina(tmpdir
, "/mnt");
285 if (mkdir(mntdir
, 0700) < 0) {
286 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
291 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
292 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
295 mntdir_mounted
= true;
297 r
= btrfs_quota_enable(mntdir
, true);
299 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
301 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
303 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
305 if (chmod(mntdir
, 0700) < 0) {
306 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
310 (void) mkdir_p_label("/var/lib/machines", 0700);
312 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
313 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
319 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
));
321 (void) umount2(mntdir
, MNT_DETACH
);
322 (void) rmdir(mntdir
);
323 (void) rmdir(tmpdir
);
329 (void) umount2(mntdir
, MNT_DETACH
);
332 (void) rmdir(mntdir
);
334 (void) rmdir(tmpdir
);
337 (void) ioctl(loop
, LOOP_CLR_FD
);
338 loop
= safe_close(loop
);
341 if (control
>= 0 && nr
>= 0)
342 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
347 static int sync_path(const char *p
) {
348 _cleanup_close_
int fd
= -1;
350 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
360 int grow_machine_directory(void) {
361 char buf
[FORMAT_BYTES_MAX
];
363 uint64_t old_size
, new_size
, max_add
;
366 /* Ensure the disk space data is accurate */
367 sync_path("/var/lib/machines");
368 sync_path("/var/lib/machines.raw");
370 if (statvfs("/var/lib/machines.raw", &a
) < 0)
373 if (statvfs("/var/lib/machines", &b
) < 0)
376 /* Don't grow if not enough disk space is available on the host */
377 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
380 /* Don't grow if at least 1/3th of the fs is still free */
381 if (b
.f_bavail
> b
.f_blocks
/ 3)
384 /* Calculate how much we are willing to add at most */
385 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
387 /* Calculate the old size */
388 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
390 /* Calculate the new size as three times the size of what is used right now */
391 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
393 /* Always, grow at least to the start size */
394 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
395 new_size
= VAR_LIB_MACHINES_SIZE_START
;
397 /* If the new size is smaller than the old size, don't grow */
398 if (new_size
< old_size
)
401 /* Ensure we never add more than the maximum */
402 if (new_size
> old_size
+ max_add
)
403 new_size
= old_size
+ max_add
;
405 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
409 /* Also bump the quota, of both the subvolume leaf qgroup, as
410 * well as of any subtree quota group by the same id but a
411 * higher level, if it exists. */
412 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
413 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
415 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));