diff options
Diffstat (limited to 'src/libshared/machine-pool.c')
| -rw-r--r-- | src/libshared/machine-pool.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/src/libshared/machine-pool.c b/src/libshared/machine-pool.c new file mode 100644 index 0000000000..c36efa0102 --- /dev/null +++ b/src/libshared/machine-pool.c @@ -0,0 +1,426 @@ +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <fcntl.h> +#include <linux/loop.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/file.h> +#include <sys/ioctl.h> +#include <sys/mount.h> +#include <sys/prctl.h> +#include <sys/stat.h> +#include <sys/statfs.h> +#include <sys/statvfs.h> +#include <unistd.h> + +#include <systemd/sd-bus-protocol.h> +#include <systemd/sd-bus.h> + +#include "alloc-util.h" +#include "btrfs-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "fs-util.h" +#include "lockfile-util.h" +#include "log.h" +#include "machine-pool.h" +#include "macro.h" +#include "missing.h" +#include "mkdir.h" +#include "mount-util.h" +#include "parse-util.h" +#include "path-util.h" +#include "process-util.h" +#include "signal-util.h" +#include "stat-util.h" +#include "string-util.h" + +#define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL) +#define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL) + +static int check_btrfs(void) { + struct statfs sfs; + + if (statfs("/var/lib/machines", &sfs) < 0) { + if (errno != ENOENT) + return -errno; + + if (statfs("/var/lib", &sfs) < 0) + return -errno; + } + + return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC); +} + +static int setup_machine_raw(uint64_t size, sd_bus_error *error) { + _cleanup_free_ char *tmp = NULL; + _cleanup_close_ int fd = -1; + struct statvfs ss; + pid_t pid = 0; + siginfo_t si; + int r; + + /* We want to be able to make use of btrfs-specific file + * system features, in particular subvolumes, reflinks and + * quota. Hence, if we detect that /var/lib/machines.raw is + * not located on btrfs, let's create a loopback file, place a + * btrfs file system into it, and mount it to + * /var/lib/machines. */ + + fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); + if (fd >= 0) { + r = fd; + fd = -1; + return r; + } + + if (errno != ENOENT) + return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m"); + + r = tempfn_xxxxxx("/var/lib/machines.raw", NULL, &tmp); + if (r < 0) + return r; + + (void) mkdir_p_label("/var/lib", 0755); + fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600); + if (fd < 0) + return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m"); + + if (fstatvfs(fd, &ss) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m"); + goto fail; + } + + if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) { + r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines."); + goto fail; + } + + if (ftruncate(fd, size) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m"); + goto fail; + } + + pid = fork(); + if (pid < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m"); + goto fail; + } + + if (pid == 0) { + + /* Child */ + + (void) reset_all_signal_handlers(); + (void) reset_signal_mask(); + assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); + + fd = safe_close(fd); + + execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL); + if (errno == ENOENT) + _exit(99); + + _exit(EXIT_FAILURE); + } + + r = wait_for_terminate(pid, &si); + if (r < 0) { + sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m"); + goto fail; + } + + pid = 0; + + if (si.si_code != CLD_EXITED) { + r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally."); + goto fail; + } + if (si.si_status == 99) { + r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing"); + goto fail; + } + if (si.si_status != 0) { + r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status); + goto fail; + } + + r = rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw"); + if (r < 0) { + sd_bus_error_set_errnof(error, r, "Failed to move /var/lib/machines.raw into place: %m"); + goto fail; + } + + r = fd; + fd = -1; + + return r; + +fail: + unlink_noerrno(tmp); + + if (pid > 1) + kill_and_sigcont(pid, SIGKILL); + + return r; +} + +int setup_machine_directory(uint64_t size, sd_bus_error *error) { + _cleanup_release_lock_file_ LockFile lock_file = LOCK_FILE_INIT; + struct loop_info64 info = { + .lo_flags = LO_FLAGS_AUTOCLEAR, + }; + _cleanup_close_ int fd = -1, control = -1, loop = -1; + _cleanup_free_ char* loopdev = NULL; + char tmpdir[] = "/tmp/machine-pool.XXXXXX", *mntdir = NULL; + bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false; + char buf[FORMAT_BYTES_MAX]; + int r, nr = -1; + + /* btrfs cannot handle file systems < 16M, hence use this as minimum */ + if (size == (uint64_t) -1) + size = VAR_LIB_MACHINES_SIZE_START; + else if (size < 16*1024*1024) + size = 16*1024*1024; + + /* Make sure we only set the directory up once at a time */ + r = make_lock_file("/run/systemd/machines.lock", LOCK_EX, &lock_file); + if (r < 0) + return r; + + r = check_btrfs(); + if (r < 0) + return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m"); + if (r > 0) { + (void) btrfs_subvol_make_label("/var/lib/machines"); + + r = btrfs_quota_enable("/var/lib/machines", true); + if (r < 0) + log_warning_errno(r, "Failed to enable quota for /var/lib/machines, ignoring: %m"); + + r = btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true); + if (r < 0) + log_warning_errno(r, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m"); + + return 1; + } + + if (path_is_mount_point("/var/lib/machines", AT_SYMLINK_FOLLOW) > 0) { + log_debug("/var/lib/machines is already a mount point, not creating loopback file for it."); + return 0; + } + + r = dir_is_populated("/var/lib/machines"); + if (r < 0 && r != -ENOENT) + return r; + if (r > 0) { + log_debug("/var/log/machines is already populated, not creating loopback file for it."); + return 0; + } + + r = mkfs_exists("btrfs"); + if (r == 0) + return sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing"); + if (r < 0) + return r; + + fd = setup_machine_raw(size, error); + if (fd < 0) + return fd; + + control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); + if (control < 0) + return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m"); + + nr = ioctl(control, LOOP_CTL_GET_FREE); + if (nr < 0) + return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m"); + + if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) { + r = -ENOMEM; + goto fail; + } + + loop = open(loopdev, O_CLOEXEC|O_RDWR|O_NOCTTY|O_NONBLOCK); + if (loop < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m"); + goto fail; + } + + if (ioctl(loop, LOOP_SET_FD, fd) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m"); + goto fail; + } + + if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m"); + goto fail; + } + + /* We need to make sure the new /var/lib/machines directory + * has an access mode of 0700 at the time it is first made + * available. mkfs will create it with 0755 however. Hence, + * let's mount the directory into an inaccessible directory + * below /tmp first, fix the access mode, and move it to the + * public place then. */ + + if (!mkdtemp(tmpdir)) { + r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m"); + goto fail; + } + tmpdir_made = true; + + mntdir = strjoina(tmpdir, "/mnt"); + if (mkdir(mntdir, 0700) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m"); + goto fail; + } + mntdir_made = true; + + if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m"); + goto fail; + } + mntdir_mounted = true; + + r = btrfs_quota_enable(mntdir, true); + if (r < 0) + log_warning_errno(r, "Failed to enable quota, ignoring: %m"); + + r = btrfs_subvol_auto_qgroup(mntdir, 0, true); + if (r < 0) + log_warning_errno(r, "Failed to set up default quota hierarchy, ignoring: %m"); + + if (chmod(mntdir, 0700) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m"); + goto fail; + } + + (void) mkdir_p_label("/var/lib/machines", 0700); + + if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) { + r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m"); + goto fail; + } + + (void) syncfs(fd); + + 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)); + + (void) umount2(mntdir, MNT_DETACH); + (void) rmdir(mntdir); + (void) rmdir(tmpdir); + + return 1; + +fail: + if (mntdir_mounted) + (void) umount2(mntdir, MNT_DETACH); + + if (mntdir_made) + (void) rmdir(mntdir); + if (tmpdir_made) + (void) rmdir(tmpdir); + + if (loop >= 0) { + (void) ioctl(loop, LOOP_CLR_FD); + loop = safe_close(loop); + } + + if (control >= 0 && nr >= 0) + (void) ioctl(control, LOOP_CTL_REMOVE, nr); + + return r; +} + +static int sync_path(const char *p) { + _cleanup_close_ int fd = -1; + + fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) + return -errno; + + if (syncfs(fd) < 0) + return -errno; + + return 0; +} + +int grow_machine_directory(void) { + char buf[FORMAT_BYTES_MAX]; + struct statvfs a, b; + uint64_t old_size, new_size, max_add; + int r; + + /* Ensure the disk space data is accurate */ + sync_path("/var/lib/machines"); + sync_path("/var/lib/machines.raw"); + + if (statvfs("/var/lib/machines.raw", &a) < 0) + return -errno; + + if (statvfs("/var/lib/machines", &b) < 0) + return -errno; + + /* Don't grow if not enough disk space is available on the host */ + if (((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) <= VAR_LIB_MACHINES_FREE_MIN) + return 0; + + /* Don't grow if at least 1/3th of the fs is still free */ + if (b.f_bavail > b.f_blocks / 3) + return 0; + + /* Calculate how much we are willing to add at most */ + max_add = ((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) - VAR_LIB_MACHINES_FREE_MIN; + + /* Calculate the old size */ + old_size = (uint64_t) b.f_blocks * (uint64_t) b.f_bsize; + + /* Calculate the new size as three times the size of what is used right now */ + new_size = ((uint64_t) b.f_blocks - (uint64_t) b.f_bavail) * (uint64_t) b.f_bsize * 3; + + /* Always, grow at least to the start size */ + if (new_size < VAR_LIB_MACHINES_SIZE_START) + new_size = VAR_LIB_MACHINES_SIZE_START; + + /* If the new size is smaller than the old size, don't grow */ + if (new_size < old_size) + return 0; + + /* Ensure we never add more than the maximum */ + if (new_size > old_size + max_add) + new_size = old_size + max_add; + + r = btrfs_resize_loopback("/var/lib/machines", new_size, true); + if (r <= 0) + return r; + + /* Also bump the quota, of both the subvolume leaf qgroup, as + * well as of any subtree quota group by the same id but a + * higher level, if it exists. */ + (void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size); + (void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size); + + log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf, sizeof(buf), new_size)); + return 1; +} |