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"
28 #include "lockfile-util.h"
30 #include "path-util.h"
31 #include "process-util.h"
32 #include "signal-util.h"
33 #include "string-util.h"
35 #include "machine-pool.h"
37 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
38 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
40 static int check_btrfs(void) {
43 if (statfs("/var/lib/machines", &sfs
) < 0) {
47 if (statfs("/var/lib", &sfs
) < 0)
51 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
54 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
55 _cleanup_free_
char *tmp
= NULL
;
56 _cleanup_close_
int fd
= -1;
62 /* We want to be able to make use of btrfs-specific file
63 * system features, in particular subvolumes, reflinks and
64 * quota. Hence, if we detect that /var/lib/machines.raw is
65 * not located on btrfs, let's create a loopback file, place a
66 * btrfs file system into it, and mount it to
67 * /var/lib/machines. */
69 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
77 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
79 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
83 (void) mkdir_p_label("/var/lib", 0755);
84 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
86 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
88 if (fstatvfs(fd
, &ss
) < 0) {
89 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
93 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
94 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
98 if (ftruncate(fd
, size
) < 0) {
99 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
105 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fork mkfs.btrfs: %m");
113 (void) reset_all_signal_handlers();
114 (void) reset_signal_mask();
115 assert_se(prctl(PR_SET_PDEATHSIG
, SIGTERM
) == 0);
119 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
126 r
= wait_for_terminate(pid
, &si
);
128 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
134 if (si
.si_code
!= CLD_EXITED
) {
135 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs died abnormally.");
138 if (si
.si_status
== 99) {
139 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
142 if (si
.si_status
!= 0) {
143 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", si
.si_status
);
147 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
149 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
162 kill_and_sigcont(pid
, SIGKILL
);
167 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
168 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
169 struct loop_info64 info
= {
170 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
172 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
173 _cleanup_free_
char* loopdev
= NULL
;
174 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
175 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
176 char buf
[FORMAT_BYTES_MAX
];
179 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
180 if (size
== (uint64_t) -1)
181 size
= VAR_LIB_MACHINES_SIZE_START
;
182 else if (size
< 16*1024*1024)
185 /* Make sure we only set the directory up once at a time */
186 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
192 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
194 (void) btrfs_subvol_make_label("/var/lib/machines");
196 r
= btrfs_quota_enable("/var/lib/machines", true);
198 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
200 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
202 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
207 if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW
) > 0) {
208 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
212 r
= dir_is_populated("/var/lib/machines");
213 if (r
< 0 && r
!= -ENOENT
)
216 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
220 r
= mkfs_exists("btrfs");
222 log_debug("mkfs.btrfs is missing, cannot create loopback file for /var/lib/machines.");
228 fd
= setup_machine_raw(size
, error
);
232 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
234 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
236 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
238 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
240 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
245 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
247 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
251 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
252 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
256 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
257 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
261 /* We need to make sure the new /var/lib/machines directory
262 * has an access mode of 0700 at the time it is first made
263 * available. mkfs will create it with 0755 however. Hence,
264 * let's mount the directory into an inaccessible directory
265 * below /tmp first, fix the access mode, and move it to the
266 * public place then. */
268 if (!mkdtemp(tmpdir
)) {
269 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
274 mntdir
= strjoina(tmpdir
, "/mnt");
275 if (mkdir(mntdir
, 0700) < 0) {
276 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
281 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
282 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
285 mntdir_mounted
= true;
287 r
= btrfs_quota_enable(mntdir
, true);
289 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
291 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
293 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
295 if (chmod(mntdir
, 0700) < 0) {
296 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
300 (void) mkdir_p_label("/var/lib/machines", 0700);
302 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
303 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
309 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
));
311 (void) umount2(mntdir
, MNT_DETACH
);
312 (void) rmdir(mntdir
);
313 (void) rmdir(tmpdir
);
319 (void) umount2(mntdir
, MNT_DETACH
);
322 (void) rmdir(mntdir
);
324 (void) rmdir(tmpdir
);
327 (void) ioctl(loop
, LOOP_CLR_FD
);
328 loop
= safe_close(loop
);
331 if (control
>= 0 && nr
>= 0)
332 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
337 static int sync_path(const char *p
) {
338 _cleanup_close_
int fd
= -1;
340 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
350 int grow_machine_directory(void) {
351 char buf
[FORMAT_BYTES_MAX
];
353 uint64_t old_size
, new_size
, max_add
;
356 /* Ensure the disk space data is accurate */
357 sync_path("/var/lib/machines");
358 sync_path("/var/lib/machines.raw");
360 if (statvfs("/var/lib/machines.raw", &a
) < 0)
363 if (statvfs("/var/lib/machines", &b
) < 0)
366 /* Don't grow if not enough disk space is available on the host */
367 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
370 /* Don't grow if at least 1/3th of the fs is still free */
371 if (b
.f_bavail
> b
.f_blocks
/ 3)
374 /* Calculate how much we are willing to add at maximum */
375 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
377 /* Calculate the old size */
378 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
380 /* Calculate the new size as three times the size of what is used right now */
381 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
383 /* Always, grow at least to the start size */
384 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
385 new_size
= VAR_LIB_MACHINES_SIZE_START
;
387 /* If the new size is smaller than the old size, don't grow */
388 if (new_size
< old_size
)
391 /* Ensure we never add more than the maximum */
392 if (new_size
> old_size
+ max_add
)
393 new_size
= old_size
+ max_add
;
395 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
399 /* Also bump the quota, of both the subvolume leaf qgroup, as
400 * well as of any subtree quota group by the same id but a
401 * higher level, if it exists. */
402 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
403 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
405 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));