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5bcd08db28
With this change we understand more than just leaf quota groups for btrfs file systems. Specifically: - When we create a subvolume we can now optionally add the new subvolume to all qgroups its parent subvolume was member of too. Alternatively it is also possible to insert an intermediary quota group between the parent's qgroups and the subvolume's leaf qgroup, which is useful for a concept of "subtree" qgroups, that contain a subvolume and all its children. - The remove logic for subvolumes has been updated to optionally remove any leaf qgroups or "subtree" qgroups, following the logic above. - The snapshot logic for subvolumes has been updated to replicate the original qgroup setup of the source, if it follows the "subtree" design described above. It will not cover qgroup setups that introduce arbitrary qgroups, especially those orthogonal to the subvolume hierarchy. This also tries to be more graceful when setting up /var/lib/machines as btrfs. For example, if mkfs.btrfs is missing we don't even try to set it up as loopback device. Fixes #1559 Fixes #1129
225 lines
8.2 KiB
C
225 lines
8.2 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2015 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "util.h"
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#include "path-util.h"
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#include "btrfs-util.h"
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#include "rm-rf.h"
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int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
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_cleanup_closedir_ DIR *d = NULL;
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int ret = 0, r;
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assert(fd >= 0);
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/* This returns the first error we run into, but nevertheless
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* tries to go on. This closes the passed fd. */
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if (!(flags & REMOVE_PHYSICAL)) {
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r = fd_is_temporary_fs(fd);
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if (r < 0) {
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safe_close(fd);
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return r;
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}
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if (!r) {
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/* We refuse to clean physical file systems
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* with this call, unless explicitly
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* requested. This is extra paranoia just to
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* be sure we never ever remove non-state
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* data */
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log_error("Attempted to remove disk file system, and we can't allow that.");
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safe_close(fd);
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return -EPERM;
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}
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}
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d = fdopendir(fd);
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if (!d) {
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safe_close(fd);
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return errno == ENOENT ? 0 : -errno;
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}
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for (;;) {
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struct dirent *de;
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bool is_dir;
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struct stat st;
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errno = 0;
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de = readdir(d);
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if (!de) {
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if (errno != 0 && ret == 0)
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ret = -errno;
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return ret;
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}
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if (streq(de->d_name, ".") || streq(de->d_name, ".."))
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continue;
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if (de->d_type == DT_UNKNOWN ||
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(de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
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if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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continue;
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}
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is_dir = S_ISDIR(st.st_mode);
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} else
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is_dir = de->d_type == DT_DIR;
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if (is_dir) {
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int subdir_fd;
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/* if root_dev is set, remove subdirectories only if device is same */
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if (root_dev && st.st_dev != root_dev->st_dev)
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continue;
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subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
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if (subdir_fd < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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continue;
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}
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/* Stop at mount points */
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r = fd_is_mount_point(fd, de->d_name, 0);
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if (r < 0) {
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if (ret == 0 && r != -ENOENT)
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ret = r;
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safe_close(subdir_fd);
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continue;
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}
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if (r) {
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safe_close(subdir_fd);
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continue;
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}
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if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
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/* This could be a subvolume, try to remove it */
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r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
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if (r < 0) {
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if (r != -ENOTTY && r != -EINVAL) {
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if (ret == 0)
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ret = r;
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safe_close(subdir_fd);
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continue;
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}
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/* ENOTTY, then it wasn't a
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* btrfs subvolume, continue
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* below. */
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} else {
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/* It was a subvolume, continue. */
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safe_close(subdir_fd);
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continue;
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}
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}
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/* We pass REMOVE_PHYSICAL here, to avoid
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* doing the fstatfs() to check the file
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* system type again for each directory */
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r = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev);
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if (r < 0 && ret == 0)
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ret = r;
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if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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}
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} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
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if (unlinkat(fd, de->d_name, 0) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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}
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}
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}
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}
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int rm_rf(const char *path, RemoveFlags flags) {
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int fd, r;
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struct statfs s;
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assert(path);
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/* We refuse to clean the root file system with this
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* call. This is extra paranoia to never cause a really
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* seriously broken system. */
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if (path_equal(path, "/")) {
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log_error("Attempted to remove entire root file system, and we can't allow that.");
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return -EPERM;
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}
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if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
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/* Try to remove as subvolume first */
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r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
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if (r >= 0)
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return r;
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if (r != -ENOTTY && r != -EINVAL && r != -ENOTDIR)
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return r;
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/* Not btrfs or not a subvolume */
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}
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fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
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if (fd < 0) {
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if (errno != ENOTDIR && errno != ELOOP)
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return -errno;
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if (!(flags & REMOVE_PHYSICAL)) {
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if (statfs(path, &s) < 0)
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return -errno;
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if (!is_temporary_fs(&s)) {
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log_error("Attempted to remove disk file system, and we can't allow that.");
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return -EPERM;
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}
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}
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if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
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if (unlink(path) < 0 && errno != ENOENT)
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return -errno;
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return 0;
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}
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r = rm_rf_children(fd, flags, NULL);
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if (flags & REMOVE_ROOT) {
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if (rmdir(path) < 0) {
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if (r == 0 && errno != ENOENT)
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r = -errno;
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}
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}
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return r;
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}
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