+++ /dev/null
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Copyright 2014 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 <stdlib.h>
-#include <sys/vfs.h>
-#include <sys/stat.h>
-
-#ifdef HAVE_LINUX_BTRFS_H
-#include <linux/btrfs.h>
-#endif
-
-#include "missing.h"
-#include "util.h"
-#include "path-util.h"
-#include "macro.h"
-#include "copy.h"
-#include "selinux-util.h"
-#include "smack-util.h"
-#include "fileio.h"
-#include "btrfs-ctree.h"
-#include "btrfs-util.h"
-
-/* WARNING: Be careful with file system ioctls! When we get an fd, we
- * need to make sure it either refers to only a regular file or
- * directory, or that it is located on btrfs, before invoking any
- * btrfs ioctls. The ioctl numbers are reused by some device drivers
- * (such as DRM), and hence might have bad effects when invoked on
- * device nodes (that reference drivers) rather than fds to normal
- * files or directories. */
-
-static int validate_subvolume_name(const char *name) {
-
- if (!filename_is_valid(name))
- return -EINVAL;
-
- if (strlen(name) > BTRFS_SUBVOL_NAME_MAX)
- return -E2BIG;
-
- return 0;
-}
-
-static int open_parent(const char *path, int flags) {
- _cleanup_free_ char *parent = NULL;
- int r, fd;
-
- assert(path);
-
- r = path_get_parent(path, &parent);
- if (r < 0)
- return r;
-
- fd = open(parent, flags);
- if (fd < 0)
- return -errno;
-
- return fd;
-}
-
-static int extract_subvolume_name(const char *path, const char **subvolume) {
- const char *fn;
- int r;
-
- assert(path);
- assert(subvolume);
-
- fn = basename(path);
-
- r = validate_subvolume_name(fn);
- if (r < 0)
- return r;
-
- *subvolume = fn;
- return 0;
-}
-
-int btrfs_is_filesystem(int fd) {
- struct statfs sfs;
-
- assert(fd >= 0);
-
- if (fstatfs(fd, &sfs) < 0)
- return -errno;
-
- return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
-}
-
-int btrfs_is_subvol(int fd) {
- struct stat st;
-
- assert(fd >= 0);
-
- /* On btrfs subvolumes always have the inode 256 */
-
- if (fstat(fd, &st) < 0)
- return -errno;
-
- if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
- return 0;
-
- return btrfs_is_filesystem(fd);
-}
-
-int btrfs_subvol_make(const char *path) {
- struct btrfs_ioctl_vol_args args = {};
- _cleanup_close_ int fd = -1;
- const char *subvolume;
- int r;
-
- assert(path);
-
- r = extract_subvolume_name(path, &subvolume);
- if (r < 0)
- return r;
-
- fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (fd < 0)
- return fd;
-
- strncpy(args.name, subvolume, sizeof(args.name)-1);
-
- if (ioctl(fd, BTRFS_IOC_SUBVOL_CREATE, &args) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_subvol_make_label(const char *path) {
- int r;
-
- assert(path);
-
- r = mac_selinux_create_file_prepare(path, S_IFDIR);
- if (r < 0)
- return r;
-
- r = btrfs_subvol_make(path);
- mac_selinux_create_file_clear();
-
- if (r < 0)
- return r;
-
- return mac_smack_fix(path, false, false);
-}
-
-int btrfs_subvol_set_read_only_fd(int fd, bool b) {
- uint64_t flags, nflags;
- struct stat st;
-
- assert(fd >= 0);
-
- if (fstat(fd, &st) < 0)
- return -errno;
-
- if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
- return -EINVAL;
-
- if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
- return -errno;
-
- if (b)
- nflags = flags | BTRFS_SUBVOL_RDONLY;
- else
- nflags = flags & ~BTRFS_SUBVOL_RDONLY;
-
- if (flags == nflags)
- return 0;
-
- if (ioctl(fd, BTRFS_IOC_SUBVOL_SETFLAGS, &nflags) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_subvol_set_read_only(const char *path, bool b) {
- _cleanup_close_ int fd = -1;
-
- fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (fd < 0)
- return -errno;
-
- return btrfs_subvol_set_read_only_fd(fd, b);
-}
-
-int btrfs_subvol_get_read_only_fd(int fd) {
- uint64_t flags;
- struct stat st;
-
- assert(fd >= 0);
-
- if (fstat(fd, &st) < 0)
- return -errno;
-
- if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
- return -EINVAL;
-
- if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
- return -errno;
-
- return !!(flags & BTRFS_SUBVOL_RDONLY);
-}
-
-int btrfs_reflink(int infd, int outfd) {
- struct stat st;
- int r;
-
- assert(infd >= 0);
- assert(outfd >= 0);
-
- /* Make sure we invoke the ioctl on a regular file, so that no
- * device driver accidentally gets it. */
-
- if (fstat(outfd, &st) < 0)
- return -errno;
-
- if (!S_ISREG(st.st_mode))
- return -EINVAL;
-
- r = ioctl(outfd, BTRFS_IOC_CLONE, infd);
- if (r < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_clone_range(int infd, uint64_t in_offset, int outfd, uint64_t out_offset, uint64_t sz) {
- struct btrfs_ioctl_clone_range_args args = {
- .src_fd = infd,
- .src_offset = in_offset,
- .src_length = sz,
- .dest_offset = out_offset,
- };
- struct stat st;
- int r;
-
- assert(infd >= 0);
- assert(outfd >= 0);
- assert(sz > 0);
-
- if (fstat(outfd, &st) < 0)
- return -errno;
-
- if (!S_ISREG(st.st_mode))
- return -EINVAL;
-
- r = ioctl(outfd, BTRFS_IOC_CLONE_RANGE, &args);
- if (r < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_get_block_device_fd(int fd, dev_t *dev) {
- struct btrfs_ioctl_fs_info_args fsi = {};
- uint64_t id;
- int r;
-
- assert(fd >= 0);
- assert(dev);
-
- r = btrfs_is_filesystem(fd);
- if (r < 0)
- return r;
- if (!r)
- return -ENOTTY;
-
- if (ioctl(fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
- return -errno;
-
- /* We won't do this for btrfs RAID */
- if (fsi.num_devices != 1)
- return 0;
-
- for (id = 1; id <= fsi.max_id; id++) {
- struct btrfs_ioctl_dev_info_args di = {
- .devid = id,
- };
- struct stat st;
-
- if (ioctl(fd, BTRFS_IOC_DEV_INFO, &di) < 0) {
- if (errno == ENODEV)
- continue;
-
- return -errno;
- }
-
- if (stat((char*) di.path, &st) < 0)
- return -errno;
-
- if (!S_ISBLK(st.st_mode))
- return -ENODEV;
-
- if (major(st.st_rdev) == 0)
- return -ENODEV;
-
- *dev = st.st_rdev;
- return 1;
- }
-
- return -ENODEV;
-}
-
-int btrfs_get_block_device(const char *path, dev_t *dev) {
- _cleanup_close_ int fd = -1;
-
- assert(path);
- assert(dev);
-
- fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
- if (fd < 0)
- return -errno;
-
- return btrfs_get_block_device_fd(fd, dev);
-}
-
-int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
- struct btrfs_ioctl_ino_lookup_args args = {
- .objectid = BTRFS_FIRST_FREE_OBJECTID
- };
- int r;
-
- assert(fd >= 0);
- assert(ret);
-
- r = btrfs_is_filesystem(fd);
- if (r < 0)
- return r;
- if (!r)
- return -ENOTTY;
-
- if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args) < 0)
- return -errno;
-
- *ret = args.treeid;
- return 0;
-}
-
-static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) {
- assert(args);
-
- /* the objectid, type, offset together make up the btrfs key,
- * which is considered a single 136byte integer when
- * comparing. This call increases the counter by one, dealing
- * with the overflow between the overflows */
-
- if (args->key.min_offset < (uint64_t) -1) {
- args->key.min_offset++;
- return true;
- }
-
- if (args->key.min_type < (uint8_t) -1) {
- args->key.min_type++;
- args->key.min_offset = 0;
- return true;
- }
-
- if (args->key.min_objectid < (uint64_t) -1) {
- args->key.min_objectid++;
- args->key.min_offset = 0;
- args->key.min_type = 0;
- return true;
- }
-
- return 0;
-}
-
-static void btrfs_ioctl_search_args_set(struct btrfs_ioctl_search_args *args, const struct btrfs_ioctl_search_header *h) {
- assert(args);
- assert(h);
-
- args->key.min_objectid = h->objectid;
- args->key.min_type = h->type;
- args->key.min_offset = h->offset;
-}
-
-static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args *args) {
- assert(args);
-
- /* Compare min and max */
-
- if (args->key.min_objectid < args->key.max_objectid)
- return -1;
- if (args->key.min_objectid > args->key.max_objectid)
- return 1;
-
- if (args->key.min_type < args->key.max_type)
- return -1;
- if (args->key.min_type > args->key.max_type)
- return 1;
-
- if (args->key.min_offset < args->key.max_offset)
- return -1;
- if (args->key.min_offset > args->key.max_offset)
- return 1;
-
- return 0;
-}
-
-#define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) \
- for ((i) = 0, \
- (sh) = (const struct btrfs_ioctl_search_header*) (args).buf; \
- (i) < (args).key.nr_items; \
- (i)++, \
- (sh) = (const struct btrfs_ioctl_search_header*) ((uint8_t*) (sh) + sizeof(struct btrfs_ioctl_search_header) + (sh)->len))
-
-#define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh) \
- ((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
-
-int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
- struct btrfs_ioctl_search_args args = {
- /* Tree of tree roots */
- .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
-
- /* Look precisely for the subvolume items */
- .key.min_type = BTRFS_ROOT_ITEM_KEY,
- .key.max_type = BTRFS_ROOT_ITEM_KEY,
-
- .key.min_offset = 0,
- .key.max_offset = (uint64_t) -1,
-
- /* No restrictions on the other components */
- .key.min_transid = 0,
- .key.max_transid = (uint64_t) -1,
- };
-
- uint64_t subvol_id;
- bool found = false;
- int r;
-
- assert(fd >= 0);
- assert(ret);
-
- r = btrfs_subvol_get_id_fd(fd, &subvol_id);
- if (r < 0)
- return r;
-
- args.key.min_objectid = args.key.max_objectid = subvol_id;
-
- while (btrfs_ioctl_search_args_compare(&args) <= 0) {
- const struct btrfs_ioctl_search_header *sh;
- unsigned i;
-
- args.key.nr_items = 256;
- if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
- return -errno;
-
- if (args.key.nr_items <= 0)
- break;
-
- FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
-
- const struct btrfs_root_item *ri;
-
- /* Make sure we start the next search at least from this entry */
- btrfs_ioctl_search_args_set(&args, sh);
-
- if (sh->objectid != subvol_id)
- continue;
- if (sh->type != BTRFS_ROOT_ITEM_KEY)
- continue;
-
- /* Older versions of the struct lacked the otime setting */
- if (sh->len < offsetof(struct btrfs_root_item, otime) + sizeof(struct btrfs_timespec))
- continue;
-
- ri = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
-
- ret->otime = (usec_t) le64toh(ri->otime.sec) * USEC_PER_SEC +
- (usec_t) le32toh(ri->otime.nsec) / NSEC_PER_USEC;
-
- ret->subvol_id = subvol_id;
- ret->read_only = !!(le64toh(ri->flags) & BTRFS_ROOT_SUBVOL_RDONLY);
-
- assert_cc(sizeof(ri->uuid) == sizeof(ret->uuid));
- memcpy(&ret->uuid, ri->uuid, sizeof(ret->uuid));
- memcpy(&ret->parent_uuid, ri->parent_uuid, sizeof(ret->parent_uuid));
-
- found = true;
- goto finish;
- }
-
- /* Increase search key by one, to read the next item, if we can. */
- if (!btrfs_ioctl_search_args_inc(&args))
- break;
- }
-
-finish:
- if (!found)
- return -ENODATA;
-
- return 0;
-}
-
-int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
-
- struct btrfs_ioctl_search_args args = {
- /* Tree of quota items */
- .key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
-
- /* The object ID is always 0 */
- .key.min_objectid = 0,
- .key.max_objectid = 0,
-
- /* Look precisely for the quota items */
- .key.min_type = BTRFS_QGROUP_STATUS_KEY,
- .key.max_type = BTRFS_QGROUP_LIMIT_KEY,
-
- /* No restrictions on the other components */
- .key.min_transid = 0,
- .key.max_transid = (uint64_t) -1,
- };
-
- uint64_t subvol_id;
- bool found_info = false, found_limit = false;
- int r;
-
- assert(fd >= 0);
- assert(ret);
-
- r = btrfs_subvol_get_id_fd(fd, &subvol_id);
- if (r < 0)
- return r;
-
- args.key.min_offset = args.key.max_offset = subvol_id;
-
- while (btrfs_ioctl_search_args_compare(&args) <= 0) {
- const struct btrfs_ioctl_search_header *sh;
- unsigned i;
-
- args.key.nr_items = 256;
- if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
- return -errno;
-
- if (args.key.nr_items <= 0)
- break;
-
- FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
-
- /* Make sure we start the next search at least from this entry */
- btrfs_ioctl_search_args_set(&args, sh);
-
- if (sh->objectid != 0)
- continue;
- if (sh->offset != subvol_id)
- continue;
-
- if (sh->type == BTRFS_QGROUP_INFO_KEY) {
- const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
-
- ret->referenced = le64toh(qii->rfer);
- ret->exclusive = le64toh(qii->excl);
-
- found_info = true;
-
- } else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
- const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
-
- ret->referenced_max = le64toh(qli->max_rfer);
- ret->exclusive_max = le64toh(qli->max_excl);
-
- if (ret->referenced_max == 0)
- ret->referenced_max = (uint64_t) -1;
- if (ret->exclusive_max == 0)
- ret->exclusive_max = (uint64_t) -1;
-
- found_limit = true;
- }
-
- if (found_info && found_limit)
- goto finish;
- }
-
- /* Increase search key by one, to read the next item, if we can. */
- if (!btrfs_ioctl_search_args_inc(&args))
- break;
- }
-
-finish:
- if (!found_limit && !found_info)
- return -ENODATA;
-
- if (!found_info) {
- ret->referenced = (uint64_t) -1;
- ret->exclusive = (uint64_t) -1;
- }
-
- if (!found_limit) {
- ret->referenced_max = (uint64_t) -1;
- ret->exclusive_max = (uint64_t) -1;
- }
-
- return 0;
-}
-
-int btrfs_defrag_fd(int fd) {
- struct stat st;
-
- assert(fd >= 0);
-
- if (fstat(fd, &st) < 0)
- return -errno;
-
- if (!S_ISREG(st.st_mode))
- return -EINVAL;
-
- if (ioctl(fd, BTRFS_IOC_DEFRAG, NULL) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_defrag(const char *p) {
- _cleanup_close_ int fd = -1;
-
- fd = open(p, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
- if (fd < 0)
- return -errno;
-
- return btrfs_defrag_fd(fd);
-}
-
-int btrfs_quota_enable_fd(int fd, bool b) {
- struct btrfs_ioctl_quota_ctl_args args = {
- .cmd = b ? BTRFS_QUOTA_CTL_ENABLE : BTRFS_QUOTA_CTL_DISABLE,
- };
- int r;
-
- assert(fd >= 0);
-
- r = btrfs_is_filesystem(fd);
- if (r < 0)
- return r;
- if (!r)
- return -ENOTTY;
-
- if (ioctl(fd, BTRFS_IOC_QUOTA_CTL, &args) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_quota_enable(const char *path, bool b) {
- _cleanup_close_ int fd = -1;
-
- fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
- if (fd < 0)
- return -errno;
-
- return btrfs_quota_enable_fd(fd, b);
-}
-
-int btrfs_quota_limit_fd(int fd, uint64_t referenced_max) {
- struct btrfs_ioctl_qgroup_limit_args args = {
- .lim.max_rfer =
- referenced_max == (uint64_t) -1 ? 0 :
- referenced_max == 0 ? 1 : referenced_max,
- .lim.flags = BTRFS_QGROUP_LIMIT_MAX_RFER,
- };
- int r;
-
- assert(fd >= 0);
-
- r = btrfs_is_filesystem(fd);
- if (r < 0)
- return r;
- if (!r)
- return -ENOTTY;
-
- if (ioctl(fd, BTRFS_IOC_QGROUP_LIMIT, &args) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_quota_limit(const char *path, uint64_t referenced_max) {
- _cleanup_close_ int fd = -1;
-
- fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
- if (fd < 0)
- return -errno;
-
- return btrfs_quota_limit_fd(fd, referenced_max);
-}
-
-int btrfs_resize_loopback_fd(int fd, uint64_t new_size, bool grow_only) {
- struct btrfs_ioctl_vol_args args = {};
- _cleanup_free_ char *p = NULL, *loop = NULL, *backing = NULL;
- _cleanup_close_ int loop_fd = -1, backing_fd = -1;
- struct stat st;
- dev_t dev = 0;
- int r;
-
- /* btrfs cannot handle file systems < 16M, hence use this as minimum */
- if (new_size < 16*1024*1024)
- new_size = 16*1024*1024;
-
- r = btrfs_get_block_device_fd(fd, &dev);
- if (r < 0)
- return r;
- if (r == 0)
- return -ENODEV;
-
- if (asprintf(&p, "/sys/dev/block/%u:%u/loop/backing_file", major(dev), minor(dev)) < 0)
- return -ENOMEM;
- r = read_one_line_file(p, &backing);
- if (r == -ENOENT)
- return -ENODEV;
- if (r < 0)
- return r;
- if (isempty(backing) || !path_is_absolute(backing))
- return -ENODEV;
-
- backing_fd = open(backing, O_RDWR|O_CLOEXEC|O_NOCTTY);
- if (backing_fd < 0)
- return -errno;
-
- if (fstat(backing_fd, &st) < 0)
- return -errno;
- if (!S_ISREG(st.st_mode))
- return -ENODEV;
-
- if (new_size == (uint64_t) st.st_size)
- return 0;
-
- if (grow_only && new_size < (uint64_t) st.st_size)
- return -EINVAL;
-
- if (asprintf(&loop, "/dev/block/%u:%u", major(dev), minor(dev)) < 0)
- return -ENOMEM;
- loop_fd = open(loop, O_RDWR|O_CLOEXEC|O_NOCTTY);
- if (loop_fd < 0)
- return -errno;
-
- if (snprintf(args.name, sizeof(args.name), "%" PRIu64, new_size) >= (int) sizeof(args.name))
- return -EINVAL;
-
- if (new_size < (uint64_t) st.st_size) {
- /* Decrease size: first decrease btrfs size, then shorten loopback */
- if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
- return -errno;
- }
-
- if (ftruncate(backing_fd, new_size) < 0)
- return -errno;
-
- if (ioctl(loop_fd, LOOP_SET_CAPACITY, 0) < 0)
- return -errno;
-
- if (new_size > (uint64_t) st.st_size) {
- /* Increase size: first enlarge loopback, then increase btrfs size */
- if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
- return -errno;
- }
-
- /* Make sure the free disk space is correctly updated for both file systems */
- (void) fsync(fd);
- (void) fsync(backing_fd);
-
- return 1;
-}
-
-int btrfs_resize_loopback(const char *p, uint64_t new_size, bool grow_only) {
- _cleanup_close_ int fd = -1;
-
- fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC);
- if (fd < 0)
- return -errno;
-
- return btrfs_resize_loopback_fd(fd, new_size, grow_only);
-}
-
-static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol_id, bool recursive) {
- struct btrfs_ioctl_search_args args = {
- .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
-
- .key.min_objectid = BTRFS_FIRST_FREE_OBJECTID,
- .key.max_objectid = BTRFS_LAST_FREE_OBJECTID,
-
- .key.min_type = BTRFS_ROOT_BACKREF_KEY,
- .key.max_type = BTRFS_ROOT_BACKREF_KEY,
-
- .key.min_transid = 0,
- .key.max_transid = (uint64_t) -1,
- };
-
- struct btrfs_ioctl_vol_args vol_args = {};
- _cleanup_close_ int subvol_fd = -1;
- struct stat st;
- bool made_writable = false;
- int r;
-
- assert(fd >= 0);
- assert(subvolume);
-
- if (fstat(fd, &st) < 0)
- return -errno;
-
- if (!S_ISDIR(st.st_mode))
- return -EINVAL;
-
- /* First, try to remove the subvolume. If it happens to be
- * already empty, this will just work. */
- strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
- if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) >= 0)
- return 0;
- if (!recursive || errno != ENOTEMPTY)
- return -errno;
-
- /* OK, the subvolume is not empty, let's look for child
- * subvolumes, and remove them, first */
- subvol_fd = openat(fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (subvol_fd < 0)
- return -errno;
-
- if (subvol_id == 0) {
- r = btrfs_subvol_get_id_fd(subvol_fd, &subvol_id);
- if (r < 0)
- return r;
- }
-
- args.key.min_offset = args.key.max_offset = subvol_id;
-
- while (btrfs_ioctl_search_args_compare(&args) <= 0) {
- const struct btrfs_ioctl_search_header *sh;
- unsigned i;
-
- args.key.nr_items = 256;
- if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
- return -errno;
-
- if (args.key.nr_items <= 0)
- break;
-
- FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
- _cleanup_free_ char *p = NULL;
- const struct btrfs_root_ref *ref;
- struct btrfs_ioctl_ino_lookup_args ino_args;
-
- btrfs_ioctl_search_args_set(&args, sh);
-
- if (sh->type != BTRFS_ROOT_BACKREF_KEY)
- continue;
- if (sh->offset != subvol_id)
- continue;
-
- ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
-
- p = strndup((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
- if (!p)
- return -ENOMEM;
-
- zero(ino_args);
- ino_args.treeid = subvol_id;
- ino_args.objectid = htole64(ref->dirid);
-
- if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
- return -errno;
-
- if (!made_writable) {
- r = btrfs_subvol_set_read_only_fd(subvol_fd, false);
- if (r < 0)
- return r;
-
- made_writable = true;
- }
-
- if (isempty(ino_args.name))
- /* Subvolume is in the top-level
- * directory of the subvolume. */
- r = subvol_remove_children(subvol_fd, p, sh->objectid, recursive);
- else {
- _cleanup_close_ int child_fd = -1;
-
- /* Subvolume is somewhere further down,
- * hence we need to open the
- * containing directory first */
-
- child_fd = openat(subvol_fd, ino_args.name, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (child_fd < 0)
- return -errno;
-
- r = subvol_remove_children(child_fd, p, sh->objectid, recursive);
- }
- if (r < 0)
- return r;
- }
-
- /* Increase search key by one, to read the next item, if we can. */
- if (!btrfs_ioctl_search_args_inc(&args))
- break;
- }
-
- /* OK, the child subvolumes should all be gone now, let's try
- * again to remove the subvolume */
- if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_subvol_remove(const char *path, bool recursive) {
- _cleanup_close_ int fd = -1;
- const char *subvolume;
- int r;
-
- assert(path);
-
- r = extract_subvolume_name(path, &subvolume);
- if (r < 0)
- return r;
-
- fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (fd < 0)
- return fd;
-
- return subvol_remove_children(fd, subvolume, 0, recursive);
-}
-
-int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive) {
- return subvol_remove_children(fd, subvolume, 0, recursive);
-}
-
-static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolume, uint64_t subvol_id, BtrfsSnapshotFlags flags) {
-
- struct btrfs_ioctl_search_args args = {
- .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
-
- .key.min_objectid = BTRFS_FIRST_FREE_OBJECTID,
- .key.max_objectid = BTRFS_LAST_FREE_OBJECTID,
-
- .key.min_type = BTRFS_ROOT_BACKREF_KEY,
- .key.max_type = BTRFS_ROOT_BACKREF_KEY,
-
- .key.min_transid = 0,
- .key.max_transid = (uint64_t) -1,
- };
-
- struct btrfs_ioctl_vol_args_v2 vol_args = {
- .flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0,
- .fd = old_fd,
- };
- int r;
- _cleanup_close_ int subvolume_fd = -1;
-
- assert(old_fd >= 0);
- assert(new_fd >= 0);
- assert(subvolume);
-
- strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
- vol_args.fd = old_fd;
-
- if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &vol_args) < 0)
- return -errno;
-
- if (!(flags & BTRFS_SNAPSHOT_RECURSIVE))
- return 0;
-
- if (subvol_id == 0) {
- r = btrfs_subvol_get_id_fd(old_fd, &subvol_id);
- if (r < 0)
- return r;
- }
-
- args.key.min_offset = args.key.max_offset = subvol_id;
-
- while (btrfs_ioctl_search_args_compare(&args) <= 0) {
- const struct btrfs_ioctl_search_header *sh;
- unsigned i;
-
- args.key.nr_items = 256;
- if (ioctl(old_fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
- return -errno;
-
- if (args.key.nr_items <= 0)
- break;
-
- FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
- _cleanup_free_ char *p = NULL, *c = NULL, *np = NULL;
- struct btrfs_ioctl_ino_lookup_args ino_args;
- const struct btrfs_root_ref *ref;
- _cleanup_close_ int old_child_fd = -1, new_child_fd = -1;
-
- btrfs_ioctl_search_args_set(&args, sh);
-
- if (sh->type != BTRFS_ROOT_BACKREF_KEY)
- continue;
- if (sh->offset != subvol_id)
- continue;
-
- ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
-
- p = strndup((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
- if (!p)
- return -ENOMEM;
-
- zero(ino_args);
- ino_args.treeid = subvol_id;
- ino_args.objectid = htole64(ref->dirid);
-
- if (ioctl(old_fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
- return -errno;
-
- /* The kernel returns an empty name if the
- * subvolume is in the top-level directory,
- * and otherwise appends a slash, so that we
- * can just concatenate easily here, without
- * adding a slash. */
- c = strappend(ino_args.name, p);
- if (!c)
- return -ENOMEM;
-
- old_child_fd = openat(old_fd, c, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (old_child_fd < 0)
- return -errno;
-
- np = strjoin(subvolume, "/", ino_args.name, NULL);
- if (!np)
- return -ENOMEM;
-
- new_child_fd = openat(new_fd, np, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (new_child_fd < 0)
- return -errno;
-
- if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
- /* If the snapshot is read-only we
- * need to mark it writable
- * temporarily, to put the subsnapshot
- * into place. */
-
- if (subvolume_fd < 0) {
- subvolume_fd = openat(new_fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (subvolume_fd < 0)
- return -errno;
- }
-
- r = btrfs_subvol_set_read_only_fd(subvolume_fd, false);
- if (r < 0)
- return r;
- }
-
- /* When btrfs clones the subvolumes, child
- * subvolumes appear as directories. Remove
- * them, so that we can create a new snapshot
- * in their place */
- if (unlinkat(new_child_fd, p, AT_REMOVEDIR) < 0) {
- int k = -errno;
-
- if (flags & BTRFS_SNAPSHOT_READ_ONLY)
- (void) btrfs_subvol_set_read_only_fd(subvolume_fd, true);
-
- return k;
- }
-
- r = subvol_snapshot_children(old_child_fd, new_child_fd, p, sh->objectid, flags & ~BTRFS_SNAPSHOT_FALLBACK_COPY);
-
- /* Restore the readonly flag */
- if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
- int k;
-
- k = btrfs_subvol_set_read_only_fd(subvolume_fd, true);
- if (r >= 0 && k < 0)
- return k;
- }
-
- if (r < 0)
- return r;
- }
-
- /* Increase search key by one, to read the next item, if we can. */
- if (!btrfs_ioctl_search_args_inc(&args))
- break;
- }
-
- return 0;
-}
-
-int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlags flags) {
- _cleanup_close_ int new_fd = -1;
- const char *subvolume;
- int r;
-
- assert(old_fd >= 0);
- assert(new_path);
-
- r = btrfs_is_subvol(old_fd);
- if (r < 0)
- return r;
- if (r == 0) {
- if (!(flags & BTRFS_SNAPSHOT_FALLBACK_COPY))
- return -EISDIR;
-
- r = btrfs_subvol_make(new_path);
- if (r < 0)
- return r;
-
- r = copy_directory_fd(old_fd, new_path, true);
- if (r < 0) {
- btrfs_subvol_remove(new_path, false);
- return r;
- }
-
- if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
- r = btrfs_subvol_set_read_only(new_path, true);
- if (r < 0) {
- btrfs_subvol_remove(new_path, false);
- return r;
- }
- }
-
- return 0;
- }
-
- r = extract_subvolume_name(new_path, &subvolume);
- if (r < 0)
- return r;
-
- new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (new_fd < 0)
- return new_fd;
-
- return subvol_snapshot_children(old_fd, new_fd, subvolume, 0, flags);
-}
-
-int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnapshotFlags flags) {
- _cleanup_close_ int old_fd = -1;
-
- assert(old_path);
- assert(new_path);
-
- old_fd = open(old_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (old_fd < 0)
- return -errno;
-
- return btrfs_subvol_snapshot_fd(old_fd, new_path, flags);
-}
~ianmdlvl / elogind.git / blobdiff