1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 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/>.
26 #ifdef HAVE_LINUX_BTRFS_H
27 #include <linux/btrfs.h>
32 #include "path-util.h"
36 #include "selinux-util.h"
37 #include "smack-util.h"
38 #include "btrfs-ctree.h"
39 #include "btrfs-util.h"
41 static int validate_subvolume_name(const char *name) {
43 if (!filename_is_valid(name))
46 if (strlen(name) > BTRFS_SUBVOL_NAME_MAX)
52 static int open_parent(const char *path, int flags) {
53 _cleanup_free_ char *parent = NULL;
58 r = path_get_parent(path, &parent);
62 fd = open(parent, flags);
69 static int extract_subvolume_name(const char *path, const char **subvolume) {
78 r = validate_subvolume_name(fn);
86 int btrfs_is_snapshot(int fd) {
90 /* On btrfs subvolumes always have the inode 256 */
92 if (fstat(fd, &st) < 0)
95 if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
98 if (fstatfs(fd, &sfs) < 0)
101 return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
104 int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_only, bool fallback_copy) {
105 struct btrfs_ioctl_vol_args_v2 args = {
106 .flags = read_only ? BTRFS_SUBVOL_RDONLY : 0,
108 _cleanup_close_ int old_fd = -1, new_fd = -1;
109 const char *subvolume;
114 old_fd = open(old_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
118 r = btrfs_is_snapshot(old_fd);
124 r = btrfs_subvol_make(new_path);
128 r = copy_directory_fd(old_fd, new_path, true);
130 btrfs_subvol_remove(new_path);
135 r = btrfs_subvol_set_read_only(new_path, true);
137 btrfs_subvol_remove(new_path);
148 r = extract_subvolume_name(new_path, &subvolume);
152 new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
156 strncpy(args.name, subvolume, sizeof(args.name)-1);
159 if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &args) < 0)
165 int btrfs_subvol_make(const char *path) {
166 struct btrfs_ioctl_vol_args args = {};
167 _cleanup_close_ int fd = -1;
168 const char *subvolume;
173 r = extract_subvolume_name(path, &subvolume);
177 fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
181 strncpy(args.name, subvolume, sizeof(args.name)-1);
183 if (ioctl(fd, BTRFS_IOC_SUBVOL_CREATE, &args) < 0)
189 int btrfs_subvol_make_label(const char *path) {
194 r = mac_selinux_create_file_prepare(path, S_IFDIR);
198 r = btrfs_subvol_make(path);
199 mac_selinux_create_file_clear();
204 return mac_smack_fix(path, false, false);
207 int btrfs_subvol_remove(const char *path) {
208 struct btrfs_ioctl_vol_args args = {};
209 _cleanup_close_ int fd = -1;
210 const char *subvolume;
215 r = extract_subvolume_name(path, &subvolume);
219 fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
223 strncpy(args.name, subvolume, sizeof(args.name)-1);
225 if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args) < 0)
231 int btrfs_subvol_set_read_only(const char *path, bool b) {
232 _cleanup_close_ int fd = -1;
233 uint64_t flags, nflags;
235 fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
239 if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
243 nflags = flags | BTRFS_SUBVOL_RDONLY;
245 nflags = flags & ~BTRFS_SUBVOL_RDONLY;
250 if (ioctl(fd, BTRFS_IOC_SUBVOL_SETFLAGS, &nflags) < 0)
256 int btrfs_subvol_get_read_only_fd(int fd) {
259 if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
262 return !!(flags & BTRFS_SUBVOL_RDONLY);
265 int btrfs_reflink(int infd, int outfd) {
271 r = ioctl(outfd, BTRFS_IOC_CLONE, infd);
278 int btrfs_get_block_device(const char *path, dev_t *dev) {
279 struct btrfs_ioctl_fs_info_args fsi = {};
280 _cleanup_close_ int fd = -1;
286 fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
290 if (ioctl(fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
293 /* We won't do this for btrfs RAID */
294 if (fsi.num_devices != 1)
297 for (id = 1; id <= fsi.max_id; id++) {
298 struct btrfs_ioctl_dev_info_args di = {
303 if (ioctl(fd, BTRFS_IOC_DEV_INFO, &di) < 0) {
310 if (stat((char*) di.path, &st) < 0)
313 if (!S_ISBLK(st.st_mode))
316 if (major(st.st_rdev) == 0)
326 int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
327 struct btrfs_ioctl_ino_lookup_args args = {
328 .objectid = BTRFS_FIRST_FREE_OBJECTID
334 if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args) < 0)
341 static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) {
344 /* the objectid, type, offset together make up the btrfs key,
345 * which is considered a single 136byte integer when
346 * comparing. This call increases the counter by one, dealing
347 * with the overflow between the overflows */
349 if (args->key.min_offset < (uint64_t) -1) {
350 args->key.min_offset++;
354 if (args->key.min_type < (uint8_t) -1) {
355 args->key.min_type++;
356 args->key.min_offset = 0;
360 if (args->key.min_objectid < (uint64_t) -1) {
361 args->key.min_objectid++;
362 args->key.min_offset = 0;
363 args->key.min_type = 0;
370 static void btrfs_ioctl_search_args_set(struct btrfs_ioctl_search_args *args, const struct btrfs_ioctl_search_header *h) {
374 args->key.min_objectid = h->objectid;
375 args->key.min_type = h->type;
376 args->key.min_offset = h->offset;
379 static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args *args) {
382 /* Compare min and max */
384 if (args->key.min_objectid < args->key.max_objectid)
386 if (args->key.min_objectid > args->key.max_objectid)
389 if (args->key.min_type < args->key.max_type)
391 if (args->key.min_type > args->key.max_type)
394 if (args->key.min_offset < args->key.max_offset)
396 if (args->key.min_offset > args->key.max_offset)
402 #define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) \
404 (sh) = (const struct btrfs_ioctl_search_header*) (args).buf; \
405 (i) < (args).key.nr_items; \
407 (sh) = (const struct btrfs_ioctl_search_header*) ((uint8_t*) (sh) + sizeof(struct btrfs_ioctl_search_header) + (sh)->len))
409 #define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh) \
410 ((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
412 int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
413 struct btrfs_ioctl_search_args args = {
414 /* Tree of tree roots */
415 .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
417 /* Look precisely for the subvolume items */
418 .key.min_type = BTRFS_ROOT_ITEM_KEY,
419 .key.max_type = BTRFS_ROOT_ITEM_KEY,
422 .key.max_offset = (uint64_t) -1,
424 /* No restrictions on the other components */
425 .key.min_transid = 0,
426 .key.max_transid = (uint64_t) -1,
436 r = btrfs_subvol_get_id_fd(fd, &subvol_id);
440 args.key.min_objectid = args.key.max_objectid = subvol_id;
442 while (btrfs_ioctl_search_args_compare(&args) <= 0) {
443 const struct btrfs_ioctl_search_header *sh;
446 args.key.nr_items = 256;
447 if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
450 if (args.key.nr_items <= 0)
453 FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
455 const struct btrfs_root_item *ri;
457 /* Make sure we start the next search at least from this entry */
458 btrfs_ioctl_search_args_set(&args, sh);
460 if (sh->objectid != subvol_id)
462 if (sh->type != BTRFS_ROOT_ITEM_KEY)
465 /* Older versions of the struct lacked the otime setting */
466 if (sh->len < offsetof(struct btrfs_root_item, otime) + sizeof(struct btrfs_timespec))
469 ri = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
471 ret->otime = (usec_t) le64toh(ri->otime.sec) * USEC_PER_SEC +
472 (usec_t) le32toh(ri->otime.nsec) / NSEC_PER_USEC;
474 ret->subvol_id = subvol_id;
475 ret->read_only = !!(le64toh(ri->flags) & BTRFS_ROOT_SUBVOL_RDONLY);
477 assert_cc(sizeof(ri->uuid) == sizeof(ret->uuid));
478 memcpy(&ret->uuid, ri->uuid, sizeof(ret->uuid));
479 memcpy(&ret->parent_uuid, ri->parent_uuid, sizeof(ret->parent_uuid));
485 /* Increase search key by one, to read the next item, if we can. */
486 if (!btrfs_ioctl_search_args_inc(&args))
497 int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
499 struct btrfs_ioctl_search_args args = {
500 /* Tree of quota items */
501 .key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
503 /* The object ID is always 0 */
504 .key.min_objectid = 0,
505 .key.max_objectid = 0,
507 /* Look precisely for the quota items */
508 .key.min_type = BTRFS_QGROUP_STATUS_KEY,
509 .key.max_type = BTRFS_QGROUP_LIMIT_KEY,
511 /* No restrictions on the other components */
512 .key.min_transid = 0,
513 .key.max_transid = (uint64_t) -1,
517 bool found_info = false, found_limit = false;
523 r = btrfs_subvol_get_id_fd(fd, &subvol_id);
527 args.key.min_offset = args.key.max_offset = subvol_id;
529 while (btrfs_ioctl_search_args_compare(&args) <= 0) {
530 const struct btrfs_ioctl_search_header *sh;
533 args.key.nr_items = 256;
534 if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
537 if (args.key.nr_items <= 0)
540 FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
542 /* Make sure we start the next search at least from this entry */
543 btrfs_ioctl_search_args_set(&args, sh);
545 if (sh->objectid != 0)
547 if (sh->offset != subvol_id)
550 if (sh->type == BTRFS_QGROUP_INFO_KEY) {
551 const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
553 ret->referred = le64toh(qii->rfer);
554 ret->exclusive = le64toh(qii->excl);
558 } else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
559 const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
561 ret->referred_max = le64toh(qli->max_rfer);
562 ret->exclusive_max = le64toh(qli->max_excl);
564 if (ret->referred_max == 0)
565 ret->referred_max = (uint64_t) -1;
566 if (ret->exclusive_max == 0)
567 ret->exclusive_max = (uint64_t) -1;
572 if (found_info && found_limit)
576 /* Increase search key by one, to read the next item, if we can. */
577 if (!btrfs_ioctl_search_args_inc(&args))
582 if (!found_limit && !found_info)
586 ret->referred = (uint64_t) -1;
587 ret->exclusive = (uint64_t) -1;
591 ret->referred_max = (uint64_t) -1;
592 ret->exclusive_max = (uint64_t) -1;
598 int btrfs_defrag_fd(int fd) {
601 if (ioctl(fd, BTRFS_IOC_DEFRAG, NULL) < 0)
607 int btrfs_defrag(const char *p) {
608 _cleanup_close_ int fd = -1;
610 fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
614 return btrfs_defrag_fd(fd);