1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2015 Lennart Poettering
10 #include <linux/loop.h>
16 #include <sys/ioctl.h>
17 #include <sys/mount.h>
18 #include <sys/prctl.h>
20 #include <sys/statfs.h>
21 #include <sys/statvfs.h>
24 #include "sd-bus-protocol.h"
27 #include "alloc-util.h"
28 #include "btrfs-util.h"
33 #include "lockfile-util.h"
35 #include "machine-pool.h"
39 #include "mount-util.h"
40 #include "parse-util.h"
41 #include "path-util.h"
42 #include "process-util.h"
43 #include "signal-util.h"
44 #include "stat-util.h"
45 #include "string-util.h"
47 #define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
48 #define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)
50 static int check_btrfs(void) {
53 if (statfs("/var/lib/machines", &sfs
) < 0) {
57 if (statfs("/var/lib", &sfs
) < 0)
61 return F_TYPE_EQUAL(sfs
.f_type
, BTRFS_SUPER_MAGIC
);
64 static int setup_machine_raw(uint64_t size
, sd_bus_error
*error
) {
65 _cleanup_free_
char *tmp
= NULL
;
66 _cleanup_close_
int fd
= -1;
71 /* We want to be able to make use of btrfs-specific file
72 * system features, in particular subvolumes, reflinks and
73 * quota. Hence, if we detect that /var/lib/machines.raw is
74 * not located on btrfs, let's create a loopback file, place a
75 * btrfs file system into it, and mount it to
76 * /var/lib/machines. */
78 fd
= open("/var/lib/machines.raw", O_RDWR
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
83 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /var/lib/machines.raw: %m");
85 r
= tempfn_xxxxxx("/var/lib/machines.raw", NULL
, &tmp
);
89 (void) mkdir_p_label("/var/lib", 0755);
90 fd
= open(tmp
, O_RDWR
|O_CREAT
|O_EXCL
|O_NOCTTY
|O_CLOEXEC
, 0600);
92 return sd_bus_error_set_errnof(error
, errno
, "Failed to create /var/lib/machines.raw: %m");
94 if (fstatvfs(fd
, &ss
) < 0) {
95 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to determine free space on /var/lib/machines.raw: %m");
99 if (ss
.f_bsize
* ss
.f_bavail
< VAR_LIB_MACHINES_FREE_MIN
) {
100 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "Not enough free disk space to set up /var/lib/machines.");
104 if (ftruncate(fd
, size
) < 0) {
105 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enlarge /var/lib/machines.raw: %m");
109 r
= safe_fork("(mkfs)", FORK_RESET_SIGNALS
|FORK_DEATHSIG
, &pid
);
111 sd_bus_error_set_errnof(error
, r
, "Failed to fork mkfs.btrfs: %m");
120 execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp
, NULL
);
127 r
= wait_for_terminate_and_check("mkfs", pid
, 0);
131 sd_bus_error_set_errnof(error
, r
, "Failed to wait for mkfs.btrfs: %m");
135 r
= sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
138 if (r
!= EXIT_SUCCESS
) {
139 r
= sd_bus_error_setf(error
, SD_BUS_ERROR_FAILED
, "mkfs.btrfs failed with error code %i", r
);
143 r
= rename_noreplace(AT_FDCWD
, tmp
, AT_FDCWD
, "/var/lib/machines.raw");
145 sd_bus_error_set_errnof(error
, r
, "Failed to move /var/lib/machines.raw into place: %m");
155 kill_and_sigcont(pid
, SIGKILL
);
160 int setup_machine_directory(uint64_t size
, sd_bus_error
*error
) {
161 _cleanup_(release_lock_file
) LockFile lock_file
= LOCK_FILE_INIT
;
162 struct loop_info64 info
= {
163 .lo_flags
= LO_FLAGS_AUTOCLEAR
,
165 _cleanup_close_
int fd
= -1, control
= -1, loop
= -1;
166 _cleanup_free_
char* loopdev
= NULL
;
167 char tmpdir
[] = "/tmp/machine-pool.XXXXXX", *mntdir
= NULL
;
168 bool tmpdir_made
= false, mntdir_made
= false, mntdir_mounted
= false;
169 char buf
[FORMAT_BYTES_MAX
];
172 /* btrfs cannot handle file systems < 16M, hence use this as minimum */
173 if (size
== (uint64_t) -1)
174 size
= VAR_LIB_MACHINES_SIZE_START
;
175 else if (size
< 16*1024*1024)
178 /* Make sure we only set the directory up once at a time */
179 r
= make_lock_file("/run/systemd/machines.lock", LOCK_EX
, &lock_file
);
185 return sd_bus_error_set_errnof(error
, r
, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
187 (void) btrfs_subvol_make_label("/var/lib/machines");
189 r
= btrfs_quota_enable("/var/lib/machines", true);
191 log_warning_errno(r
, "Failed to enable quota for /var/lib/machines, ignoring: %m");
193 r
= btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
195 log_warning_errno(r
, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
200 if (path_is_mount_point("/var/lib/machines", NULL
, AT_SYMLINK_FOLLOW
) > 0) {
201 log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
205 r
= dir_is_populated("/var/lib/machines");
206 if (r
< 0 && r
!= -ENOENT
)
209 log_debug("/var/log/machines is already populated, not creating loopback file for it.");
213 r
= mkfs_exists("btrfs");
215 return sd_bus_error_set_errnof(error
, ENOENT
, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
219 fd
= setup_machine_raw(size
, error
);
223 control
= open("/dev/loop-control", O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NONBLOCK
);
225 return sd_bus_error_set_errnof(error
, errno
, "Failed to open /dev/loop-control: %m");
227 nr
= ioctl(control
, LOOP_CTL_GET_FREE
);
229 return sd_bus_error_set_errnof(error
, errno
, "Failed to allocate loop device: %m");
231 if (asprintf(&loopdev
, "/dev/loop%i", nr
) < 0) {
236 loop
= open(loopdev
, O_CLOEXEC
|O_RDWR
|O_NOCTTY
|O_NONBLOCK
);
238 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to open loopback device: %m");
242 if (ioctl(loop
, LOOP_SET_FD
, fd
) < 0) {
243 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to bind loopback device: %m");
247 if (ioctl(loop
, LOOP_SET_STATUS64
, &info
) < 0) {
248 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to enable auto-clear for loopback device: %m");
252 /* We need to make sure the new /var/lib/machines directory
253 * has an access mode of 0700 at the time it is first made
254 * available. mkfs will create it with 0755 however. Hence,
255 * let's mount the directory into an inaccessible directory
256 * below /tmp first, fix the access mode, and move it to the
257 * public place then. */
259 if (!mkdtemp(tmpdir
)) {
260 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount parent directory: %m");
265 mntdir
= strjoina(tmpdir
, "/mnt");
266 if (mkdir(mntdir
, 0700) < 0) {
267 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to create temporary mount directory: %m");
272 if (mount(loopdev
, mntdir
, "btrfs", 0, NULL
) < 0) {
273 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount loopback device: %m");
276 mntdir_mounted
= true;
278 r
= btrfs_quota_enable(mntdir
, true);
280 log_warning_errno(r
, "Failed to enable quota, ignoring: %m");
282 r
= btrfs_subvol_auto_qgroup(mntdir
, 0, true);
284 log_warning_errno(r
, "Failed to set up default quota hierarchy, ignoring: %m");
286 if (chmod(mntdir
, 0700) < 0) {
287 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to fix owner: %m");
291 (void) mkdir_p_label("/var/lib/machines", 0700);
293 if (mount(mntdir
, "/var/lib/machines", NULL
, MS_BIND
, NULL
) < 0) {
294 r
= sd_bus_error_set_errnof(error
, errno
, "Failed to mount directory into right place: %m");
300 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
));
302 (void) umount2(mntdir
, MNT_DETACH
);
303 (void) rmdir(mntdir
);
304 (void) rmdir(tmpdir
);
310 (void) umount2(mntdir
, MNT_DETACH
);
313 (void) rmdir(mntdir
);
315 (void) rmdir(tmpdir
);
318 (void) ioctl(loop
, LOOP_CLR_FD
);
319 loop
= safe_close(loop
);
322 if (control
>= 0 && nr
>= 0)
323 (void) ioctl(control
, LOOP_CTL_REMOVE
, nr
);
328 static int sync_path(const char *p
) {
329 _cleanup_close_
int fd
= -1;
331 fd
= open(p
, O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
341 int grow_machine_directory(void) {
342 char buf
[FORMAT_BYTES_MAX
];
344 uint64_t old_size
, new_size
, max_add
;
347 /* Ensure the disk space data is accurate */
348 sync_path("/var/lib/machines");
349 sync_path("/var/lib/machines.raw");
351 if (statvfs("/var/lib/machines.raw", &a
) < 0)
354 if (statvfs("/var/lib/machines", &b
) < 0)
357 /* Don't grow if not enough disk space is available on the host */
358 if (((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) <= VAR_LIB_MACHINES_FREE_MIN
)
361 /* Don't grow if at least 1/3th of the fs is still free */
362 if (b
.f_bavail
> b
.f_blocks
/ 3)
365 /* Calculate how much we are willing to add at most */
366 max_add
= ((uint64_t) a
.f_bavail
* (uint64_t) a
.f_bsize
) - VAR_LIB_MACHINES_FREE_MIN
;
368 /* Calculate the old size */
369 old_size
= (uint64_t) b
.f_blocks
* (uint64_t) b
.f_bsize
;
371 /* Calculate the new size as three times the size of what is used right now */
372 new_size
= ((uint64_t) b
.f_blocks
- (uint64_t) b
.f_bavail
) * (uint64_t) b
.f_bsize
* 3;
374 /* Always, grow at least to the start size */
375 if (new_size
< VAR_LIB_MACHINES_SIZE_START
)
376 new_size
= VAR_LIB_MACHINES_SIZE_START
;
378 /* If the new size is smaller than the old size, don't grow */
379 if (new_size
< old_size
)
382 /* Ensure we never add more than the maximum */
383 if (new_size
> old_size
+ max_add
)
384 new_size
= old_size
+ max_add
;
386 r
= btrfs_resize_loopback("/var/lib/machines", new_size
, true);
390 /* Also bump the quota, of both the subvolume leaf qgroup, as
391 * well as of any subtree quota group by the same id but a
392 * higher level, if it exists. */
393 (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size
);
394 (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size
);
396 log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf
, sizeof(buf
), new_size
));