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/prctl.h>
24 #include <sys/statvfs.h>
25 #include <sys/mount.h>
28 #include "process-util.h"
29 #include "lockfile-util.h"
31 #include "btrfs-util.h"
32 #include "path-util.h"
33 #include "signal-util.h"
34 #include "machine-pool.h"
36 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
37 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
39 static int check_btrfs(void) {
42 if (statfs("/var/lib/machines", &sfs
) < 0) {
46 if (statfs("/var/lib", &sfs
) < 0)
50 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
53 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
54 _cleanup_free_
char *tmp
= NULL
;
55 _cleanup_close_
int fd
= -1;
61 /* We want to be able to make use of btrfs-specific file
62 * system features, in particular subvolumes, reflinks and
63 * quota. Hence, if we detect that /var/lib/machines.raw is
64 * not located on btrfs, let's create a loopback file, place a
65 * btrfs file system into it, and mount it to
66 * /var/lib/machines. */
68 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
76 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
78 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
82 (void) mkdir_p_label("/var/lib", 0755);
83 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
85 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
87 if (fstatvfs(fd
, &ss
) < 0) {
88 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
92 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
93 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
97 if (ftruncate(fd
, size
) < 0) {
98 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
104 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fork mkfs.btrfs: %m");
112 (void) reset_all_signal_handlers();
113 (void) reset_signal_mask();
114 assert_se(prctl(PR_SET_PDEATHSIG
, SIGTERM
) == 0);
118 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
125 r
= wait_for_terminate(pid
, &si
);
127 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
133 if (si
.si_code
!= CLD_EXITED
) {
134 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs died abnormally.");
137 if (si
.si_status
== 99) {
138 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
141 if (si
.si_status
!= 0) {
142 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", si
.si_status
);
146 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
148 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
161 kill_and_sigcont(pid
, SIGKILL
);
166 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
167 _cleanup_release_lock_file_ LockFile lock_file
= LOCK_FILE_INIT
;
168 struct loop_info64 info
= {
169 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
171 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
172 _cleanup_free_
char* loopdev
= NULL
;
173 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
174 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
175 char buf
[FORMAT_BYTES_MAX
];
178 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
179 if (size
== (uint64_t) -1)
180 size
= VAR_LIB_MACHINES_SIZE_START
;
181 else if (size
< 16*1024*1024)
184 /* Make sure we only set the directory up once at a time */
185 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
191 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
193 (void) btrfs_subvol_make_label("/var/lib/machines");
195 r
= btrfs_quota_enable("/var/lib/machines", true);
197 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
199 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
201 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
206 if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW
) > 0) {
207 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
211 r
= dir_is_populated("/var/lib/machines");
212 if (r
< 0 && r
!= -ENOENT
)
215 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
219 r
= mkfs_exists("btrfs");
221 log_debug("mkfs.btrfs is missing, cannot create loopback file for /var/lib/machines.");
227 fd
= setup_machine_raw(size
, error
);
231 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
233 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
235 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
237 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
239 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
244 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
246 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
250 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
251 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
255 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
256 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
260 /* We need to make sure the new /var/lib/machines directory
261 * has an access mode of 0700 at the time it is first made
262 * available. mkfs will create it with 0755 however. Hence,
263 * let's mount the directory into an inaccessible directory
264 * below /tmp first, fix the access mode, and move it to the
265 * public place then. */
267 if (!mkdtemp(tmpdir
)) {
268 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
273 mntdir
= strjoina(tmpdir
, "/mnt");
274 if (mkdir(mntdir
, 0700) < 0) {
275 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
280 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
281 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
284 mntdir_mounted
= true;
286 r
= btrfs_quota_enable(mntdir
, true);
288 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
290 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
292 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
294 if (chmod(mntdir
, 0700) < 0) {
295 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
299 (void) mkdir_p_label("/var/lib/machines", 0700);
301 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
302 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
308 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
));
310 (void) umount2(mntdir
, MNT_DETACH
);
311 (void) rmdir(mntdir
);
312 (void) rmdir(tmpdir
);
318 (void) umount2(mntdir
, MNT_DETACH
);
321 (void) rmdir(mntdir
);
323 (void) rmdir(tmpdir
);
326 (void) ioctl(loop
, LOOP_CLR_FD
);
327 loop
= safe_close(loop
);
330 if (control
>= 0 && nr
>= 0)
331 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
336 static int sync_path(const char *p
) {
337 _cleanup_close_
int fd
= -1;
339 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
349 int grow_machine_directory(void) {
350 char buf
[FORMAT_BYTES_MAX
];
352 uint64_t old_size
, new_size
, max_add
;
355 /* Ensure the disk space data is accurate */
356 sync_path("/var/lib/machines");
357 sync_path("/var/lib/machines.raw");
359 if (statvfs("/var/lib/machines.raw", &a
) < 0)
362 if (statvfs("/var/lib/machines", &b
) < 0)
365 /* Don't grow if not enough disk space is available on the host */
366 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
369 /* Don't grow if at least 1/3th of the fs is still free */
370 if (b
.f_bavail
> b
.f_blocks
/ 3)
373 /* Calculate how much we are willing to add at maximum */
374 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
376 /* Calculate the old size */
377 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
379 /* Calculate the new size as three times the size of what is used right now */
380 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
382 /* Always, grow at least to the start size */
383 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
384 new_size
= VAR_LIB_MACHINES_SIZE_START
;
386 /* If the new size is smaller than the old size, don't grow */
387 if (new_size
< old_size
)
390 /* Ensure we never add more than the maximum */
391 if (new_size
> old_size
+ max_add
)
392 new_size
= old_size
+ max_add
;
394 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
398 /* Also bump the quota, of both the subvolume leaf qgroup, as
399 * well as of any subtree quota group by the same id but a
400 * higher level, if it exists. */
401 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
402 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
404 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));