/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** 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 <sys/mount.h> #include <sys/prctl.h> #include <sys/statvfs.h> #include <sys/vfs.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 "machine-pool.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" #include "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) return 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 == -ENOENT) { log_debug("mkfs.btrfs is missing, cannot create loopback file for /var/lib/machines."); return 0; } 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 maximum */ 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; }