2 This file is part of systemd.
4 Copyright 2015 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <linux/loop.h>
28 #include <sys/ioctl.h>
29 #include <sys/mount.h>
30 #include <sys/prctl.h>
32 #include <sys/statfs.h>
33 #include <sys/statvfs.h>
36 #include "sd-bus-protocol.h"
39 #include "alloc-util.h"
40 #include "btrfs-util.h"
44 #include "lockfile-util.h"
46 #include "machine-pool.h"
50 #include "mount-util.h"
51 #include "parse-util.h"
52 #include "path-util.h"
53 #include "process-util.h"
54 #include "signal-util.h"
55 #include "stat-util.h"
56 #include "string-util.h"
58 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
59 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
61 static int check_btrfs(void) {
64 if (statfs("/var/lib/machines", &sfs
) < 0) {
68 if (statfs("/var/lib", &sfs
) < 0)
72 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
75 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
76 _cleanup_free_
char *tmp
= NULL
;
77 _cleanup_close_
int fd
= -1;
83 /* We want to be able to make use of btrfs-specific file
84 * system features, in particular subvolumes, reflinks and
85 * quota. Hence, if we detect that /var/lib/machines.raw is
86 * not located on btrfs, let's create a loopback file, place a
87 * btrfs file system into it, and mount it to
88 * /var/lib/machines. */
90 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
98 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
100 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
104 (void) mkdir_p_label("/var/lib", 0755);
105 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
107 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
109 if (fstatvfs(fd
, &ss
) < 0) {
110 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
114 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
115 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
119 if (ftruncate(fd
, size
) < 0) {
120 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
126 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fork mkfs.btrfs: %m");
134 (void) reset_all_signal_handlers();
135 (void) reset_signal_mask();
136 assert_se(prctl(PR_SET_PDEATHSIG
, SIGTERM
) == 0);
140 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
147 r
= wait_for_terminate(pid
, &si
);
149 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
155 if (si
.si_code
!= CLD_EXITED
) {
156 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs died abnormally.");
159 if (si
.si_status
== 99) {
160 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
163 if (si
.si_status
!= 0) {
164 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", si
.si_status
);
168 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
170 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
183 kill_and_sigcont(pid
, SIGKILL
);
188 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
189 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
190 struct loop_info64 info
= {
191 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
193 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
194 _cleanup_free_
char* loopdev
= NULL
;
195 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
196 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
197 char buf
[FORMAT_BYTES_MAX
];
200 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
201 if (size
== (uint64_t) -1)
202 size
= VAR_LIB_MACHINES_SIZE_START
;
203 else if (size
< 16*1024*1024)
206 /* Make sure we only set the directory up once at a time */
207 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
213 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
215 (void) btrfs_subvol_make_label("/var/lib/machines");
217 r
= btrfs_quota_enable("/var/lib/machines", true);
219 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
221 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
223 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
228 if (path_is_mount_point("/var/lib/machines", NULL
, AT_SYMLINK_FOLLOW
) > 0) {
229 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
233 r
= dir_is_populated("/var/lib/machines");
234 if (r
< 0 && r
!= -ENOENT
)
237 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
241 r
= mkfs_exists("btrfs");
243 return sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
247 fd
= setup_machine_raw(size
, error
);
251 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
253 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
255 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
257 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
259 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
264 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
266 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
270 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
271 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
275 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
276 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
280 /* We need to make sure the new /var/lib/machines directory
281 * has an access mode of 0700 at the time it is first made
282 * available. mkfs will create it with 0755 however. Hence,
283 * let's mount the directory into an inaccessible directory
284 * below /tmp first, fix the access mode, and move it to the
285 * public place then. */
287 if (!mkdtemp(tmpdir
)) {
288 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
293 mntdir
= strjoina(tmpdir
, "/mnt");
294 if (mkdir(mntdir
, 0700) < 0) {
295 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
300 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
301 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
304 mntdir_mounted
= true;
306 r
= btrfs_quota_enable(mntdir
, true);
308 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
310 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
312 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
314 if (chmod(mntdir
, 0700) < 0) {
315 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
319 (void) mkdir_p_label("/var/lib/machines", 0700);
321 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
322 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
328 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
));
330 (void) umount2(mntdir
, MNT_DETACH
);
331 (void) rmdir(mntdir
);
332 (void) rmdir(tmpdir
);
338 (void) umount2(mntdir
, MNT_DETACH
);
341 (void) rmdir(mntdir
);
343 (void) rmdir(tmpdir
);
346 (void) ioctl(loop
, LOOP_CLR_FD
);
347 loop
= safe_close(loop
);
350 if (control
>= 0 && nr
>= 0)
351 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
356 static int sync_path(const char *p
) {
357 _cleanup_close_
int fd
= -1;
359 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
369 int grow_machine_directory(void) {
370 char buf
[FORMAT_BYTES_MAX
];
372 uint64_t old_size
, new_size
, max_add
;
375 /* Ensure the disk space data is accurate */
376 sync_path("/var/lib/machines");
377 sync_path("/var/lib/machines.raw");
379 if (statvfs("/var/lib/machines.raw", &a
) < 0)
382 if (statvfs("/var/lib/machines", &b
) < 0)
385 /* Don't grow if not enough disk space is available on the host */
386 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
389 /* Don't grow if at least 1/3th of the fs is still free */
390 if (b
.f_bavail
> b
.f_blocks
/ 3)
393 /* Calculate how much we are willing to add at most */
394 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
396 /* Calculate the old size */
397 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
399 /* Calculate the new size as three times the size of what is used right now */
400 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
402 /* Always, grow at least to the start size */
403 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
404 new_size
= VAR_LIB_MACHINES_SIZE_START
;
406 /* If the new size is smaller than the old size, don't grow */
407 if (new_size
< old_size
)
410 /* Ensure we never add more than the maximum */
411 if (new_size
> old_size
+ max_add
)
412 new_size
= old_size
+ max_add
;
414 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
418 /* Also bump the quota, of both the subvolume leaf qgroup, as
419 * well as of any subtree quota group by the same id but a
420 * higher level, if it exists. */
421 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
422 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
424 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));