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/>.
24 #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"
45 #include "lockfile-util.h"
47 #include "machine-pool.h"
51 #include "mount-util.h"
52 #include "parse-util.h"
53 #include "path-util.h"
54 #include "process-util.h"
55 #include "signal-util.h"
56 #include "stat-util.h"
57 #include "string-util.h"
59 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
60 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
62 static int check_btrfs(void) {
65 if (statfs("/var/lib/machines", &sfs
) < 0) {
69 if (statfs("/var/lib", &sfs
) < 0)
73 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
76 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
77 _cleanup_free_
char *tmp
= NULL
;
78 _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");
127 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fork mkfs.btrfs: %m");
135 (void) reset_all_signal_handlers();
136 (void) reset_signal_mask();
137 assert_se(prctl(PR_SET_PDEATHSIG
, SIGTERM
) == 0);
141 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
148 r
= wait_for_terminate(pid
, &si
);
150 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
156 if (si
.si_code
!= CLD_EXITED
) {
157 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs died abnormally.");
160 if (si
.si_status
== 99) {
161 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
164 if (si
.si_status
!= 0) {
165 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", si
.si_status
);
169 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
171 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
184 kill_and_sigcont(pid
, SIGKILL
);
189 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
190 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
191 struct loop_info64 info
= {
192 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
194 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
195 _cleanup_free_
char* loopdev
= NULL
;
196 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
197 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
198 char buf
[FORMAT_BYTES_MAX
];
201 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
202 if (size
== (uint64_t) -1)
203 size
= VAR_LIB_MACHINES_SIZE_START
;
204 else if (size
< 16*1024*1024)
207 /* Make sure we only set the directory up once at a time */
208 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
214 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
216 (void) btrfs_subvol_make_label("/var/lib/machines");
218 r
= btrfs_quota_enable("/var/lib/machines", true);
220 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
222 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
224 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
229 if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW
) > 0) {
230 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
234 r
= dir_is_populated("/var/lib/machines");
235 if (r
< 0 && r
!= -ENOENT
)
238 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
242 r
= mkfs_exists("btrfs");
244 log_debug("mkfs.btrfs is missing, cannot create loopback file for /var/lib/machines.");
250 fd
= setup_machine_raw(size
, error
);
254 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
256 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
258 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
260 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
262 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
267 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
269 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
273 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
274 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
278 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
279 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
283 /* We need to make sure the new /var/lib/machines directory
284 * has an access mode of 0700 at the time it is first made
285 * available. mkfs will create it with 0755 however. Hence,
286 * let's mount the directory into an inaccessible directory
287 * below /tmp first, fix the access mode, and move it to the
288 * public place then. */
290 if (!mkdtemp(tmpdir
)) {
291 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
296 mntdir
= strjoina(tmpdir
, "/mnt");
297 if (mkdir(mntdir
, 0700) < 0) {
298 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
303 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
304 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
307 mntdir_mounted
= true;
309 r
= btrfs_quota_enable(mntdir
, true);
311 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
313 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
315 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
317 if (chmod(mntdir
, 0700) < 0) {
318 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
322 (void) mkdir_p_label("/var/lib/machines", 0700);
324 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
325 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
331 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
));
333 (void) umount2(mntdir
, MNT_DETACH
);
334 (void) rmdir(mntdir
);
335 (void) rmdir(tmpdir
);
341 (void) umount2(mntdir
, MNT_DETACH
);
344 (void) rmdir(mntdir
);
346 (void) rmdir(tmpdir
);
349 (void) ioctl(loop
, LOOP_CLR_FD
);
350 loop
= safe_close(loop
);
353 if (control
>= 0 && nr
>= 0)
354 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
359 static int sync_path(const char *p
) {
360 _cleanup_close_
int fd
= -1;
362 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
372 int grow_machine_directory(void) {
373 char buf
[FORMAT_BYTES_MAX
];
375 uint64_t old_size
, new_size
, max_add
;
378 /* Ensure the disk space data is accurate */
379 sync_path("/var/lib/machines");
380 sync_path("/var/lib/machines.raw");
382 if (statvfs("/var/lib/machines.raw", &a
) < 0)
385 if (statvfs("/var/lib/machines", &b
) < 0)
388 /* Don't grow if not enough disk space is available on the host */
389 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
392 /* Don't grow if at least 1/3th of the fs is still free */
393 if (b
.f_bavail
> b
.f_blocks
/ 3)
396 /* Calculate how much we are willing to add at most */
397 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
399 /* Calculate the old size */
400 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
402 /* Calculate the new size as three times the size of what is used right now */
403 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
405 /* Always, grow at least to the start size */
406 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
407 new_size
= VAR_LIB_MACHINES_SIZE_START
;
409 /* If the new size is smaller than the old size, don't grow */
410 if (new_size
< old_size
)
413 /* Ensure we never add more than the maximum */
414 if (new_size
> old_size
+ max_add
)
415 new_size
= old_size
+ max_add
;
417 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
421 /* Also bump the quota, of both the subvolume leaf qgroup, as
422 * well as of any subtree quota group by the same id but a
423 * higher level, if it exists. */
424 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
425 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
427 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));