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/mount.h>
23 #include <sys/prctl.h>
24 #include <sys/statvfs.h>
27 #include "btrfs-util.h"
30 #include "lockfile-util.h"
31 #include "machine-pool.h"
33 #include "parse-util.h"
34 #include "path-util.h"
35 #include "process-util.h"
36 #include "signal-util.h"
37 #include "string-util.h"
40 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
41 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
43 static int check_btrfs(void) {
46 if (statfs("/var/lib/machines", &sfs
) < 0) {
50 if (statfs("/var/lib", &sfs
) < 0)
54 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
57 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
58 _cleanup_free_
char *tmp
= NULL
;
59 _cleanup_close_
int fd
= -1;
65 /* We want to be able to make use of btrfs-specific file
66 * system features, in particular subvolumes, reflinks and
67 * quota. Hence, if we detect that /var/lib/machines.raw is
68 * not located on btrfs, let's create a loopback file, place a
69 * btrfs file system into it, and mount it to
70 * /var/lib/machines. */
72 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
80 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
82 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
86 (void) mkdir_p_label("/var/lib", 0755);
87 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
89 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
91 if (fstatvfs(fd
, &ss
) < 0) {
92 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
96 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
97 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
101 if (ftruncate(fd
, size
) < 0) {
102 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
108 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fork mkfs.btrfs: %m");
116 (void) reset_all_signal_handlers();
117 (void) reset_signal_mask();
118 assert_se(prctl(PR_SET_PDEATHSIG
, SIGTERM
) == 0);
122 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
129 r
= wait_for_terminate(pid
, &si
);
131 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
137 if (si
.si_code
!= CLD_EXITED
) {
138 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs died abnormally.");
141 if (si
.si_status
== 99) {
142 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
145 if (si
.si_status
!= 0) {
146 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", si
.si_status
);
150 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
152 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
165 kill_and_sigcont(pid
, SIGKILL
);
170 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
171 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
172 struct loop_info64 info
= {
173 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
175 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
176 _cleanup_free_
char* loopdev
= NULL
;
177 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
178 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
179 char buf
[FORMAT_BYTES_MAX
];
182 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
183 if (size
== (uint64_t) -1)
184 size
= VAR_LIB_MACHINES_SIZE_START
;
185 else if (size
< 16*1024*1024)
188 /* Make sure we only set the directory up once at a time */
189 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
195 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
197 (void) btrfs_subvol_make_label("/var/lib/machines");
199 r
= btrfs_quota_enable("/var/lib/machines", true);
201 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
203 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
205 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
210 if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW
) > 0) {
211 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
215 r
= dir_is_populated("/var/lib/machines");
216 if (r
< 0 && r
!= -ENOENT
)
219 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
223 r
= mkfs_exists("btrfs");
225 log_debug("mkfs.btrfs is missing, cannot create loopback file for /var/lib/machines.");
231 fd
= setup_machine_raw(size
, error
);
235 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
237 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
239 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
241 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
243 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
248 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
250 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
254 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
255 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
259 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
260 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
264 /* We need to make sure the new /var/lib/machines directory
265 * has an access mode of 0700 at the time it is first made
266 * available. mkfs will create it with 0755 however. Hence,
267 * let's mount the directory into an inaccessible directory
268 * below /tmp first, fix the access mode, and move it to the
269 * public place then. */
271 if (!mkdtemp(tmpdir
)) {
272 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
277 mntdir
= strjoina(tmpdir
, "/mnt");
278 if (mkdir(mntdir
, 0700) < 0) {
279 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
284 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
285 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
288 mntdir_mounted
= true;
290 r
= btrfs_quota_enable(mntdir
, true);
292 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
294 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
296 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
298 if (chmod(mntdir
, 0700) < 0) {
299 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
303 (void) mkdir_p_label("/var/lib/machines", 0700);
305 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
306 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
312 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
));
314 (void) umount2(mntdir
, MNT_DETACH
);
315 (void) rmdir(mntdir
);
316 (void) rmdir(tmpdir
);
322 (void) umount2(mntdir
, MNT_DETACH
);
325 (void) rmdir(mntdir
);
327 (void) rmdir(tmpdir
);
330 (void) ioctl(loop
, LOOP_CLR_FD
);
331 loop
= safe_close(loop
);
334 if (control
>= 0 && nr
>= 0)
335 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
340 static int sync_path(const char *p
) {
341 _cleanup_close_
int fd
= -1;
343 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
353 int grow_machine_directory(void) {
354 char buf
[FORMAT_BYTES_MAX
];
356 uint64_t old_size
, new_size
, max_add
;
359 /* Ensure the disk space data is accurate */
360 sync_path("/var/lib/machines");
361 sync_path("/var/lib/machines.raw");
363 if (statvfs("/var/lib/machines.raw", &a
) < 0)
366 if (statvfs("/var/lib/machines", &b
) < 0)
369 /* Don't grow if not enough disk space is available on the host */
370 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
373 /* Don't grow if at least 1/3th of the fs is still free */
374 if (b
.f_bavail
> b
.f_blocks
/ 3)
377 /* Calculate how much we are willing to add at maximum */
378 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
380 /* Calculate the old size */
381 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
383 /* Calculate the new size as three times the size of what is used right now */
384 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
386 /* Always, grow at least to the start size */
387 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
388 new_size
= VAR_LIB_MACHINES_SIZE_START
;
390 /* If the new size is smaller than the old size, don't grow */
391 if (new_size
< old_size
)
394 /* Ensure we never add more than the maximum */
395 if (new_size
> old_size
+ max_add
)
396 new_size
= old_size
+ max_add
;
398 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
402 /* Also bump the quota, of both the subvolume leaf qgroup, as
403 * well as of any subtree quota group by the same id but a
404 * higher level, if it exists. */
405 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
406 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
408 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));