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systemd/src/shared/btrfs-util.c
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Daan De Meyer 69a283c5f2 shared: Clean up includes 
Split out of #37344.
2025-05-24 14:00:44 +02:00

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <fcntl.h>
#include <linux/btrfs.h>
#include <linux/btrfs_tree.h>
#include <linux/magic.h>
#include <stdio.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "chase.h"
#include "chattr-util.h"
#include "copy.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "log.h"
#include "path-util.h"
#include "rm-rf.h"
#include "sparse-endian.h"
#include "stat-util.h"
#include "string-util.h"
#include "time-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. */
int btrfs_is_subvol_at(int dir_fd, const char *path) {
struct stat st;
assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
/* On btrfs subvolumes always have the inode 256 */
if (fstatat(dir_fd, strempty(path), &st, isempty(path) ? AT_EMPTY_PATH : 0) < 0)
return -errno;
if (!btrfs_might_be_subvol(&st))
return 0;
return is_fs_type_at(dir_fd, path, BTRFS_SUPER_MAGIC);
}
int btrfs_subvol_set_read_only_at(int dir_fd, const char *path, bool b) {
_cleanup_close_ int fd = -EBADF;
uint64_t flags, nflags;
struct stat st;
assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
fd = xopenat(dir_fd, path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (fd < 0)
return fd;
if (fstat(fd, &st) < 0)
return -errno;
if (!btrfs_might_be_subvol(&st))
return -EINVAL;
if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
return -errno;
nflags = UPDATE_FLAG(flags, BTRFS_SUBVOL_RDONLY, b);
if (flags == nflags)
return 0;
return RET_NERRNO(ioctl(fd, BTRFS_IOC_SUBVOL_SETFLAGS, &nflags));
}
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 (!btrfs_might_be_subvol(&st))
return -EINVAL;
if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
return -errno;
return !!(flags & BTRFS_SUBVOL_RDONLY);
}
int btrfs_get_block_device_at(int dir_fd, const char *path, dev_t *ret) {
struct btrfs_ioctl_fs_info_args fsi = {};
_cleanup_close_ int fd = -EBADF;
uint64_t id;
int r;
assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
assert(path);
assert(ret);
fd = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
if (fd < 0)
return fd;
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
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) {
*ret = 0;
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;
}
/* For the root fs — when no initrd is involved — btrfs returns /dev/root on any kernels from
* the past few years. That sucks, as we have no API to determine the actual root then. let's
* return an recognizable error for this case, so that the caller can maybe print a nice
* message about this.
*
* https://bugzilla.kernel.org/show_bug.cgi?id=89721 */
if (path_equal((char*) di.path, "/dev/root"))
return -EUCLEAN;
if (stat((char*) di.path, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENOTBLK;
if (major(st.st_rdev) == 0)
return -ENODEV;
*ret = st.st_rdev;
return 1;
}
return -ENODEV;
}
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 = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args) < 0)
return -errno;
*ret = args.treeid;
return 0;
}
int btrfs_subvol_get_id(int fd, const char *subvol, uint64_t *ret) {
_cleanup_close_ int subvol_fd = -EBADF;
assert(fd >= 0);
assert(ret);
subvol_fd = openat(fd, subvol, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (subvol_fd < 0)
return -errno;
return btrfs_subvol_get_id_fd(subvol_fd, ret);
}
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_MAX) {
args->key.min_offset++;
return true;
}
if (args->key.min_type < UINT8_MAX) {
args->key.min_type++;
args->key.min_offset = 0;
return true;
}
if (args->key.min_objectid < UINT64_MAX) {
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) {
int r;
assert(args);
/* Compare min and max */
r = CMP(args->key.min_objectid, args->key.max_objectid);
if (r != 0)
return r;
r = CMP(args->key.min_type, args->key.max_type);
if (r != 0)
return r;
return CMP(args->key.min_offset, args->key.max_offset);
}
typedef struct BtrfsForeachIterator {
const struct btrfs_ioctl_search_args *args;
size_t offset;
unsigned index;
struct btrfs_ioctl_search_header *header;
const void **body;
} BtrfsForeachIterator;
static int btrfs_iterate(BtrfsForeachIterator *i) {
assert(i);
assert(i->args);
assert(i->header);
assert(i->body);
if (i->index >= i->args->key.nr_items)
return 0; /* end */
assert_cc(BTRFS_SEARCH_ARGS_BUFSIZE >= sizeof(struct btrfs_ioctl_search_header));
if (i->offset > BTRFS_SEARCH_ARGS_BUFSIZE - sizeof(struct btrfs_ioctl_search_header))
return -EBADMSG;
struct btrfs_ioctl_search_header h;
memcpy(&h, (const uint8_t*) i->args->buf + i->offset, sizeof(struct btrfs_ioctl_search_header));
if (i->offset > BTRFS_SEARCH_ARGS_BUFSIZE - sizeof(struct btrfs_ioctl_search_header) - h.len)
return -EBADMSG;
*i->body = (const uint8_t*) i->args->buf + i->offset + sizeof(struct btrfs_ioctl_search_header);
*i->header = h;
i->offset += sizeof(struct btrfs_ioctl_search_header) + h.len;
i->index++;
return 1;
}
/* Iterates through a series of struct btrfs_file_extent_item elements. They are unfortunately not aligned,
* hence we copy out the header from them */
#define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(_sh, _body, _args) \
for (BtrfsForeachIterator iterator = { \
.args = &(_args), \
.header = &(_sh), \
.body = &(_body), \
}; \
btrfs_iterate(&iterator) > 0; )
int btrfs_subvol_get_info_fd(int fd, uint64_t subvol_id, 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_MAX,
/* No restrictions on the other components */
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
bool found = false;
int r;
assert(fd >= 0);
assert(ret);
/* Make sure this works on O_PATH fds */
_cleanup_close_ int fd_close = -EBADF;
fd = fd_reopen_condition(fd, O_CLOEXEC|O_RDONLY|O_DIRECTORY, O_PATH, &fd_close);
if (fd < 0)
return fd;
if (subvol_id == 0) {
r = btrfs_subvol_get_id_fd(fd, &subvol_id);
if (r < 0)
return r;
} else {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
}
args.key.min_objectid = args.key.max_objectid = subvol_id;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
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(sh, body, args) {
/* 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;
const struct btrfs_root_item *ri = body;
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:
return found ? 0 : -ENODATA;
}
int btrfs_qgroup_get_quota_fd(int fd, uint64_t qgroupid, 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_MAX,
};
bool found_info = false, found_limit = false;
int r;
assert(fd >= 0);
assert(ret);
if (qgroupid == 0) {
r = btrfs_subvol_get_id_fd(fd, &qgroupid);
if (r < 0)
return r;
} else {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
}
args.key.min_offset = args.key.max_offset = qgroupid;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0) {
if (errno == ENOENT) /* quota tree is missing: quota disabled */
break;
return -errno;
}
if (args.key.nr_items <= 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, 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 != qgroupid)
continue;
if (sh.type == BTRFS_QGROUP_INFO_KEY) {
const struct btrfs_qgroup_info_item *qii = body;
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 = body;
if (le64toh(qli->flags) & BTRFS_QGROUP_LIMIT_MAX_RFER)
ret->referenced_max = le64toh(qli->max_rfer);
else
ret->referenced_max = UINT64_MAX;
if (le64toh(qli->flags) & BTRFS_QGROUP_LIMIT_MAX_EXCL)
ret->exclusive_max = le64toh(qli->max_excl);
else
ret->exclusive_max = UINT64_MAX;
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_MAX;
ret->exclusive = UINT64_MAX;
}
if (!found_limit) {
ret->referenced_max = UINT64_MAX;
ret->exclusive_max = UINT64_MAX;
}
return 0;
}
int btrfs_log_dev_root(int level, int ret, const char *p) {
return log_full_errno(level, ret,
"File system behind %s is reported by btrfs to be backed by pseudo-device /dev/root, which is not a valid userspace accessible device node. "
"Cannot determine correct backing block device.", p);
}
int btrfs_qgroup_get_quota(const char *path, uint64_t qgroupid, BtrfsQuotaInfo *ret) {
_cleanup_close_ int fd = -EBADF;
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return btrfs_qgroup_get_quota_fd(fd, qgroupid, ret);
}
int btrfs_subvol_find_subtree_qgroup(int fd, uint64_t subvol_id, uint64_t *ret) {
uint64_t level, lowest = UINT64_MAX, lowest_qgroupid = 0;
_cleanup_free_ uint64_t *qgroups = NULL;
int r, n;
assert(fd >= 0);
assert(ret);
/* This finds the "subtree" qgroup for a specific
* subvolume. This only works for subvolumes that have been
* prepared with btrfs_subvol_auto_qgroup_fd() with
* insert_intermediary_qgroup=true (or equivalent). For others
* it will return the leaf qgroup instead. The two cases may
* be distinguished via the return value, which is 1 in case
* an appropriate "subtree" qgroup was found, and 0
* otherwise. */
if (subvol_id == 0) {
r = btrfs_subvol_get_id_fd(fd, &subvol_id);
if (r < 0)
return r;
}
r = btrfs_qgroupid_split(subvol_id, &level, NULL);
if (r < 0)
return r;
if (level != 0) /* Input must be a leaf qgroup */
return -EINVAL;
n = btrfs_qgroup_find_parents(fd, subvol_id, &qgroups);
if (n < 0)
return n;
for (int i = 0; i < n; i++) {
uint64_t id;
r = btrfs_qgroupid_split(qgroups[i], &level, &id);
if (r < 0)
return r;
if (id != subvol_id)
continue;
if (lowest == UINT64_MAX || level < lowest) {
lowest_qgroupid = qgroups[i];
lowest = level;
}
}
if (lowest == UINT64_MAX) {
/* No suitable higher-level qgroup found, let's return
* the leaf qgroup instead, and indicate that with the
* return value. */
*ret = subvol_id;
return 0;
}
*ret = lowest_qgroupid;
return 1;
}
int btrfs_subvol_get_subtree_quota_fd(int fd, uint64_t subvol_id, BtrfsQuotaInfo *ret) {
uint64_t qgroupid;
int r;
assert(fd >= 0);
assert(ret);
/* This determines the quota data of the qgroup with the
* lowest level, that shares the id part with the specified
* subvolume. This is useful for determining the quota data
* for entire subvolume subtrees, as long as the subtrees have
* been set up with btrfs_qgroup_subvol_auto_fd() or in a
* compatible way */
r = btrfs_subvol_find_subtree_qgroup(fd, subvol_id, &qgroupid);
if (r < 0)
return r;
return btrfs_qgroup_get_quota_fd(fd, qgroupid, ret);
}
int btrfs_subvol_get_subtree_quota(const char *path, uint64_t subvol_id, BtrfsQuotaInfo *ret) {
_cleanup_close_ int fd = -EBADF;
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return btrfs_subvol_get_subtree_quota_fd(fd, subvol_id, ret);
}
int btrfs_defrag_fd(int fd) {
int r;
assert(fd >= 0);
r = fd_verify_regular(fd);
if (r < 0)
return r;
return RET_NERRNO(ioctl(fd, BTRFS_IOC_DEFRAG, NULL));
}
int btrfs_defrag(const char *p) {
_cleanup_close_ int fd = -EBADF;
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 = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
return RET_NERRNO(ioctl(fd, BTRFS_IOC_QUOTA_CTL, &args));
}
int btrfs_quota_enable(const char *path, bool b) {
_cleanup_close_ int fd = -EBADF;
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_qgroup_set_limit_fd(int fd, uint64_t qgroupid, uint64_t referenced_max) {
struct btrfs_ioctl_qgroup_limit_args args = {
.lim.max_rfer = referenced_max,
.lim.flags = BTRFS_QGROUP_LIMIT_MAX_RFER,
};
int r;
assert(fd >= 0);
if (qgroupid == 0) {
r = btrfs_subvol_get_id_fd(fd, &qgroupid);
if (r < 0)
return r;
} else {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
}
args.qgroupid = qgroupid;
for (unsigned c = 0;; c++) {
if (ioctl(fd, BTRFS_IOC_QGROUP_LIMIT, &args) < 0) {
if (errno == EBUSY && c < 10) {
(void) btrfs_quota_scan_wait(fd);
continue;
}
return -errno;
}
break;
}
return 0;
}
int btrfs_qgroup_set_limit(const char *path, uint64_t qgroupid, uint64_t referenced_max) {
_cleanup_close_ int fd = -EBADF;
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return btrfs_qgroup_set_limit_fd(fd, qgroupid, referenced_max);
}
int btrfs_subvol_set_subtree_quota_limit_fd(int fd, uint64_t subvol_id, uint64_t referenced_max) {
uint64_t qgroupid;
int r;
assert(fd >= 0);
r = btrfs_subvol_find_subtree_qgroup(fd, subvol_id, &qgroupid);
if (r < 0)
return r;
return btrfs_qgroup_set_limit_fd(fd, qgroupid, referenced_max);
}
int btrfs_subvol_set_subtree_quota_limit(const char *path, uint64_t subvol_id, uint64_t referenced_max) {
_cleanup_close_ int fd = -EBADF;
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return btrfs_subvol_set_subtree_quota_limit_fd(fd, subvol_id, referenced_max);
}
int btrfs_qgroupid_make(uint64_t level, uint64_t id, uint64_t *ret) {
assert(ret);
if (level >= (UINT64_C(1) << (64 - BTRFS_QGROUP_LEVEL_SHIFT)))
return -EINVAL;
if (id >= (UINT64_C(1) << BTRFS_QGROUP_LEVEL_SHIFT))
return -EINVAL;
*ret = (level << BTRFS_QGROUP_LEVEL_SHIFT) | id;
return 0;
}
int btrfs_qgroupid_split(uint64_t qgroupid, uint64_t *level, uint64_t *id) {
assert(level || id);
if (level)
*level = qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
if (id)
*id = qgroupid & ((UINT64_C(1) << BTRFS_QGROUP_LEVEL_SHIFT) - 1);
return 0;
}
static int qgroup_create_or_destroy(int fd, bool b, uint64_t qgroupid) {
struct btrfs_ioctl_qgroup_create_args args = {
.create = b,
.qgroupid = qgroupid,
};
int r;
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
for (unsigned c = 0;; c++) {
if (ioctl(fd, BTRFS_IOC_QGROUP_CREATE, &args) < 0) {
/* On old kernels if quota is not enabled, we get EINVAL. On newer kernels we get
* ENOTCONN. Let's always convert this to ENOTCONN to make this recognizable
* everywhere the same way. */
if (IN_SET(errno, EINVAL, ENOTCONN))
return -ENOTCONN;
if (errno == EBUSY && c < 10) {
(void) btrfs_quota_scan_wait(fd);
continue;
}
return -errno;
}
break;
}
return 0;
}
int btrfs_qgroup_create(int fd, uint64_t qgroupid) {
return qgroup_create_or_destroy(fd, true, qgroupid);
}
int btrfs_qgroup_destroy(int fd, uint64_t qgroupid) {
return qgroup_create_or_destroy(fd, false, qgroupid);
}
int btrfs_qgroup_destroy_recursive(int fd, uint64_t qgroupid) {
_cleanup_free_ uint64_t *qgroups = NULL;
uint64_t subvol_id;
int n, r;
/* Destroys the specified qgroup, but unassigns it from all
* its parents first. Also, it recursively destroys all
* qgroups it is assigned to that have the same id part of the
* qgroupid as the specified group. */
r = btrfs_qgroupid_split(qgroupid, NULL, &subvol_id);
if (r < 0)
return r;
n = btrfs_qgroup_find_parents(fd, qgroupid, &qgroups);
if (n < 0)
return n;
for (int i = 0; i < n; i++) {
uint64_t id;
r = btrfs_qgroupid_split(qgroups[i], NULL, &id);
if (r < 0)
return r;
r = btrfs_qgroup_unassign(fd, qgroupid, qgroups[i]);
if (r < 0)
return r;
if (id != subvol_id)
continue;
/* The parent qgroupid shares the same id part with
* us? If so, destroy it too. */
(void) btrfs_qgroup_destroy_recursive(fd, qgroups[i]);
}
return btrfs_qgroup_destroy(fd, qgroupid);
}
int btrfs_quota_scan_start(int fd) {
struct btrfs_ioctl_quota_rescan_args args = {};
assert(fd >= 0);
return RET_NERRNO(ioctl(fd, BTRFS_IOC_QUOTA_RESCAN, &args));
}
int btrfs_quota_scan_wait(int fd) {
assert(fd >= 0);
return RET_NERRNO(ioctl(fd, BTRFS_IOC_QUOTA_RESCAN_WAIT));
}
int btrfs_quota_scan_ongoing(int fd) {
struct btrfs_ioctl_quota_rescan_args args = {};
assert(fd >= 0);
if (ioctl(fd, BTRFS_IOC_QUOTA_RESCAN_STATUS, &args) < 0)
return -errno;
return !!args.flags;
}
static int qgroup_assign_or_unassign(int fd, bool b, uint64_t child, uint64_t parent) {
struct btrfs_ioctl_qgroup_assign_args args = {
.assign = b,
.src = child,
.dst = parent,
};
int r;
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
for (unsigned c = 0;; c++) {
r = ioctl(fd, BTRFS_IOC_QGROUP_ASSIGN, &args);
if (r < 0) {
if (errno == EBUSY && c < 10) {
(void) btrfs_quota_scan_wait(fd);
continue;
}
return -errno;
}
if (r == 0)
return 0;
/* If the return value is > 0, we need to request a rescan */
(void) btrfs_quota_scan_start(fd);
return 1;
}
}
int btrfs_qgroup_assign(int fd, uint64_t child, uint64_t parent) {
return qgroup_assign_or_unassign(fd, true, child, parent);
}
int btrfs_qgroup_unassign(int fd, uint64_t child, uint64_t parent) {
return qgroup_assign_or_unassign(fd, false, child, parent);
}
static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol_id, BtrfsRemoveFlags 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_MAX,
};
struct btrfs_ioctl_vol_args vol_args = {};
_cleanup_close_ int subvol_fd = -EBADF;
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;
subvol_fd = openat(fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
if (subvol_fd < 0)
return -errno;
/* Let's check if this is actually a subvolume. Note that this is mostly redundant, as BTRFS_IOC_SNAP_DESTROY
* would fail anyway if it is not. However, it's a good thing to check this ahead of time so that we can return
* ENOTTY unconditionally in this case. This is different from the ioctl() which will return EPERM/EACCES if we
* don't have the privileges to remove subvolumes, regardless if the specified directory is actually a
* subvolume or not. In order to make it easy for callers to cover the "this is not a btrfs subvolume" case
* let's prefer ENOTTY over EPERM/EACCES though. */
r = btrfs_is_subvol_fd(subvol_fd);
if (r < 0)
return r;
if (r == 0) /* Not a btrfs subvolume */
return -ENOTTY;
if (subvol_id == 0) {
r = btrfs_subvol_get_id_fd(subvol_fd, &subvol_id);
if (r < 0)
return r;
}
/* 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) {
(void) btrfs_qgroup_destroy_recursive(fd, subvol_id); /* for the leaf subvolumes, the qgroup id is identical to the subvol id */
return 0;
}
if (!(flags & BTRFS_REMOVE_RECURSIVE) || errno != ENOTEMPTY)
return -errno;
/* OK, the subvolume is not empty, let's look for child
* subvolumes, and remove them, first */
args.key.min_offset = args.key.max_offset = subvol_id;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
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(sh, body, args) {
_cleanup_free_ char *p = NULL;
btrfs_ioctl_search_args_set(&args, &sh);
if (sh.type != BTRFS_ROOT_BACKREF_KEY)
continue;
if (sh.offset != subvol_id)
continue;
const struct btrfs_root_ref *ref = body;
p = memdup_suffix0((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
if (!p)
return -ENOMEM;
struct btrfs_ioctl_ino_lookup_args ino_args = {
.treeid = subvol_id,
.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, flags);
else {
_cleanup_close_ int child_fd = -EBADF;
/* 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|O_NOFOLLOW);
if (child_fd < 0)
return -errno;
r = subvol_remove_children(child_fd, p, sh.objectid, flags);
}
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;
(void) btrfs_qgroup_destroy_recursive(fd, subvol_id);
return 0;
}
int btrfs_subvol_remove_at(int dir_fd, const char *path, BtrfsRemoveFlags flags) {
_cleanup_free_ char *subvolume = NULL;
_cleanup_close_ int fd = -EBADF;
int r;
assert(path);
fd = chase_and_openat(dir_fd, path, CHASE_PARENT|CHASE_EXTRACT_FILENAME, O_CLOEXEC, &subvolume);
if (fd < 0)
return fd;
r = btrfs_validate_subvolume_name(subvolume);
if (r < 0)
return r;
return subvol_remove_children(fd, subvolume, 0, flags);
}
int btrfs_qgroup_copy_limits(int fd, uint64_t old_qgroupid, uint64_t new_qgroupid) {
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_LIMIT_KEY,
.key.max_type = BTRFS_QGROUP_LIMIT_KEY,
/* For our qgroup */
.key.min_offset = old_qgroupid,
.key.max_offset = old_qgroupid,
/* No restrictions on the other components */
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
int r;
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0) {
if (errno == ENOENT) /* quota tree missing: quota is not enabled, hence nothing to copy */
break;
return -errno;
}
if (args.key.nr_items <= 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, args) {
struct btrfs_ioctl_qgroup_limit_args qargs;
unsigned c;
/* 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.type != BTRFS_QGROUP_LIMIT_KEY)
continue;
if (sh.offset != old_qgroupid)
continue;
/* We found the entry, now copy things over. */
const struct btrfs_qgroup_limit_item *qli = body;
qargs = (struct btrfs_ioctl_qgroup_limit_args) {
.qgroupid = new_qgroupid,
.lim.max_rfer = le64toh(qli->max_rfer),
.lim.max_excl = le64toh(qli->max_excl),
.lim.rsv_rfer = le64toh(qli->rsv_rfer),
.lim.rsv_excl = le64toh(qli->rsv_excl),
.lim.flags = le64toh(qli->flags) & (BTRFS_QGROUP_LIMIT_MAX_RFER|
BTRFS_QGROUP_LIMIT_MAX_EXCL|
BTRFS_QGROUP_LIMIT_RSV_RFER|
BTRFS_QGROUP_LIMIT_RSV_EXCL),
};
for (c = 0;; c++) {
if (ioctl(fd, BTRFS_IOC_QGROUP_LIMIT, &qargs) < 0) {
if (errno == EBUSY && c < 10) {
(void) btrfs_quota_scan_wait(fd);
continue;
}
return -errno;
}
break;
}
return 1;
}
/* Increase search key by one, to read the next item, if we can. */
if (!btrfs_ioctl_search_args_inc(&args))
break;
}
return 0;
}
static int copy_quota_hierarchy(int fd, uint64_t old_subvol_id, uint64_t new_subvol_id) {
_cleanup_free_ uint64_t *old_qgroups = NULL, *old_parent_qgroups = NULL;
bool copy_from_parent = false, insert_intermediary_qgroup = false;
int n_old_qgroups, n_old_parent_qgroups, r;
uint64_t old_parent_id;
assert(fd >= 0);
/* Copies a reduced form of quota information from the old to
* the new subvolume. */
n_old_qgroups = btrfs_qgroup_find_parents(fd, old_subvol_id, &old_qgroups);
if (n_old_qgroups <= 0) /* Nothing to copy */
return n_old_qgroups;
assert(old_qgroups); /* Coverity gets confused by the macro iterator allocating this, add a hint */
r = btrfs_subvol_get_parent(fd, old_subvol_id, &old_parent_id);
if (r == -ENXIO)
/* We have no parent, hence nothing to copy. */
n_old_parent_qgroups = 0;
else if (r < 0)
return r;
else {
n_old_parent_qgroups = btrfs_qgroup_find_parents(fd, old_parent_id, &old_parent_qgroups);
if (n_old_parent_qgroups < 0)
return n_old_parent_qgroups;
}
for (int i = 0; i < n_old_qgroups; i++) {
uint64_t id;
r = btrfs_qgroupid_split(old_qgroups[i], NULL, &id);
if (r < 0)
return r;
if (id == old_subvol_id) {
/* The old subvolume was member of a qgroup
* that had the same id, but a different level
* as it self. Let's set up something similar
* in the destination. */
insert_intermediary_qgroup = true;
break;
}
for (int j = 0; j < n_old_parent_qgroups; j++)
if (old_parent_qgroups[j] == old_qgroups[i])
/* The old subvolume shared a common
* parent qgroup with its parent
* subvolume. Let's set up something
* similar in the destination. */
copy_from_parent = true;
}
if (!insert_intermediary_qgroup && !copy_from_parent)
return 0;
return btrfs_subvol_auto_qgroup_fd(fd, new_subvol_id, insert_intermediary_qgroup);
}
static int copy_subtree_quota_limits(int fd, uint64_t old_subvol, uint64_t new_subvol) {
uint64_t old_subtree_qgroup, new_subtree_qgroup;
bool changed;
int r;
/* First copy the leaf limits */
r = btrfs_qgroup_copy_limits(fd, old_subvol, new_subvol);
if (r < 0)
return r;
changed = r > 0;
/* Then, try to copy the subtree limits, if there are any. */
r = btrfs_subvol_find_subtree_qgroup(fd, old_subvol, &old_subtree_qgroup);
if (r < 0)
return r;
if (r == 0)
return changed;
r = btrfs_subvol_find_subtree_qgroup(fd, new_subvol, &new_subtree_qgroup);
if (r < 0)
return r;
if (r == 0)
return changed;
r = btrfs_qgroup_copy_limits(fd, old_subtree_qgroup, new_subtree_qgroup);
if (r != 0)
return r;
return changed;
}
static int subvol_snapshot_children(
int old_fd,
int new_fd,
const char *subvolume,
uint64_t old_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_MAX,
};
struct btrfs_ioctl_vol_args_v2 vol_args = {
.flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0,
.fd = old_fd,
};
_cleanup_close_ int subvolume_fd = -EBADF;
uint64_t new_subvol_id;
int r;
assert(old_fd >= 0);
assert(new_fd >= 0);
assert(subvolume);
strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &vol_args) < 0)
return -errno;
if (FLAGS_SET(flags, BTRFS_SNAPSHOT_LOCK_BSD)) {
subvolume_fd = xopenat_lock(new_fd, subvolume,
O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW,
LOCK_BSD,
LOCK_EX);
if (subvolume_fd < 0)
return subvolume_fd;
r = btrfs_is_subvol_fd(subvolume_fd);
if (r < 0)
return r;
if (r == 0)
return -EEXIST;
}
if (!(flags & BTRFS_SNAPSHOT_RECURSIVE) &&
!(flags & BTRFS_SNAPSHOT_QUOTA))
return flags & BTRFS_SNAPSHOT_LOCK_BSD ? TAKE_FD(subvolume_fd) : 0;
if (old_subvol_id == 0) {
r = btrfs_subvol_get_id_fd(old_fd, &old_subvol_id);
if (r < 0)
return r;
}
r = btrfs_subvol_get_id(new_fd, vol_args.name, &new_subvol_id);
if (r < 0)
return r;
if (flags & BTRFS_SNAPSHOT_QUOTA)
(void) copy_quota_hierarchy(new_fd, old_subvol_id, new_subvol_id);
if (!(flags & BTRFS_SNAPSHOT_RECURSIVE)) {
if (flags & BTRFS_SNAPSHOT_QUOTA)
(void) copy_subtree_quota_limits(new_fd, old_subvol_id, new_subvol_id);
return flags & BTRFS_SNAPSHOT_LOCK_BSD ? TAKE_FD(subvolume_fd) : 0;
}
args.key.min_offset = args.key.max_offset = old_subvol_id;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
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(sh, body, args) {
_cleanup_free_ char *p = NULL, *c = NULL, *np = NULL;
_cleanup_close_ int old_child_fd = -EBADF, new_child_fd = -EBADF;
btrfs_ioctl_search_args_set(&args, &sh);
if (sh.type != BTRFS_ROOT_BACKREF_KEY)
continue;
/* Avoid finding the source subvolume a second time */
if (sh.offset != old_subvol_id)
continue;
/* Avoid running into loops if the new subvolume is below the old one. */
if (sh.objectid == new_subvol_id)
continue;
const struct btrfs_root_ref *ref = body;
p = memdup_suffix0((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
if (!p)
return -ENOMEM;
struct btrfs_ioctl_ino_lookup_args ino_args = {
.treeid = old_subvol_id,
.objectid = htole64(ref->dirid),
};
if (ioctl(old_fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
return -errno;
c = path_join(ino_args.name, p);
if (!c)
return -ENOMEM;
old_child_fd = openat(old_fd, c, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
if (old_child_fd < 0)
return -errno;
np = path_join(subvolume, ino_args.name);
if (!np)
return -ENOMEM;
new_child_fd = openat(new_fd, np, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
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|O_NOFOLLOW);
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 empty
* 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|BTRFS_SNAPSHOT_LOCK_BSD));
/* 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;
}
if (flags & BTRFS_SNAPSHOT_QUOTA)
(void) copy_subtree_quota_limits(new_fd, old_subvol_id, new_subvol_id);
return flags & BTRFS_SNAPSHOT_LOCK_BSD ? TAKE_FD(subvolume_fd) : 0;
}
int btrfs_subvol_snapshot_at_full(
int dir_fdf,
const char *from,
int dir_fdt,
const char *to,
BtrfsSnapshotFlags flags,
copy_progress_path_t progress_path,
copy_progress_bytes_t progress_bytes,
void *userdata) {
_cleanup_free_ char *subvolume = NULL;
_cleanup_close_ int old_fd = -EBADF, new_fd = -EBADF, subvolume_fd = -EBADF;
int r;
assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD);
assert(dir_fdt >= 0 || dir_fdt == AT_FDCWD);
assert(to);
old_fd = xopenat(dir_fdf, from, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (old_fd < 0)
return old_fd;
new_fd = chase_and_openat(dir_fdt, to, CHASE_PARENT|CHASE_EXTRACT_FILENAME, O_CLOEXEC, &subvolume);
if (new_fd < 0)
return new_fd;
r = btrfs_validate_subvolume_name(subvolume);
if (r < 0)
return r;
r = btrfs_is_subvol_at(dir_fdf, from);
if (r < 0)
return r;
if (r == 0) {
bool plain_directory = false;
/* If the source isn't a proper subvolume, fail unless fallback is requested */
if (!(flags & BTRFS_SNAPSHOT_FALLBACK_COPY))
return -EISDIR;
r = btrfs_subvol_make(new_fd, subvolume);
if (r < 0) {
if (ERRNO_IS_NOT_SUPPORTED(r) && (flags & BTRFS_SNAPSHOT_FALLBACK_DIRECTORY)) {
/* If the destination doesn't support subvolumes, then use a plain directory, if that's requested. */
if (mkdirat(new_fd, subvolume, 0755) < 0)
return -errno;
plain_directory = true;
} else
return r;
}
if (FLAGS_SET(flags, BTRFS_SNAPSHOT_LOCK_BSD)) {
subvolume_fd = xopenat_lock(new_fd, subvolume,
O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW,
LOCK_BSD,
LOCK_EX);
if (subvolume_fd < 0)
return subvolume_fd;
if (!plain_directory) {
r = btrfs_is_subvol_fd(subvolume_fd);
if (r < 0)
return r;
if (r == 0)
return -EEXIST;
}
}
r = copy_directory_at_full(
dir_fdf, from,
new_fd, subvolume,
COPY_MERGE_EMPTY|
COPY_REFLINK|
COPY_SAME_MOUNT|
COPY_HARDLINKS|
COPY_ALL_XATTRS|
(FLAGS_SET(flags, BTRFS_SNAPSHOT_SIGINT) ? COPY_SIGINT : 0)|
(FLAGS_SET(flags, BTRFS_SNAPSHOT_SIGTERM) ? COPY_SIGTERM : 0),
progress_path,
progress_bytes,
userdata);
if (r < 0)
goto fallback_fail;
if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
if (plain_directory) {
/* Plain directories have no recursive read-only flag, but something pretty close to
* it: the IMMUTABLE bit. Let's use this here, if this is requested. */
if (flags & BTRFS_SNAPSHOT_FALLBACK_IMMUTABLE)
(void) chattr_at(new_fd, subvolume, FS_IMMUTABLE_FL, FS_IMMUTABLE_FL);
} else {
r = btrfs_subvol_set_read_only_at(new_fd, subvolume, true);
if (r < 0)
goto fallback_fail;
}
}
return flags & BTRFS_SNAPSHOT_LOCK_BSD ? TAKE_FD(subvolume_fd) : 0;
fallback_fail:
(void) rm_rf_at(new_fd, subvolume, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);
return r;
}
return subvol_snapshot_children(old_fd, new_fd, subvolume, 0, flags);
}
int btrfs_qgroup_find_parents(int fd, uint64_t qgroupid, uint64_t **ret) {
struct btrfs_ioctl_search_args args = {
/* Tree of quota items */
.key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
/* Look precisely for the quota relation items */
.key.min_type = BTRFS_QGROUP_RELATION_KEY,
.key.max_type = BTRFS_QGROUP_RELATION_KEY,
/* No restrictions on the other components */
.key.min_offset = 0,
.key.max_offset = UINT64_MAX,
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
_cleanup_free_ uint64_t *items = NULL;
size_t n_items = 0;
int r;
assert(fd >= 0);
assert(ret);
if (qgroupid == 0) {
r = btrfs_subvol_get_id_fd(fd, &qgroupid);
if (r < 0)
return r;
} else {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
}
args.key.min_objectid = args.key.max_objectid = qgroupid;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
_unused_ const void *body;
args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0) {
if (errno == ENOENT) /* quota tree missing: quota is disabled */
break;
return -errno;
}
if (args.key.nr_items <= 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, args) {
/* Make sure we start the next search at least from this entry */
btrfs_ioctl_search_args_set(&args, &sh);
if (sh.type != BTRFS_QGROUP_RELATION_KEY)
continue;
if (sh.offset < sh.objectid)
continue;
if (sh.objectid != qgroupid)
continue;
if (!GREEDY_REALLOC(items, n_items+1))
return -ENOMEM;
items[n_items++] = sh.offset;
}
/* Increase search key by one, to read the next item, if we can. */
if (!btrfs_ioctl_search_args_inc(&args))
break;
}
assert((n_items > 0) == !!items);
assert(n_items <= INT_MAX);
*ret = TAKE_PTR(items);
return (int) n_items;
}
int btrfs_subvol_auto_qgroup_fd(int fd, uint64_t subvol_id, bool insert_intermediary_qgroup) {
_cleanup_free_ uint64_t *qgroups = NULL;
_cleanup_close_ int real_fd = -EBADF;
uint64_t parent_subvol;
bool changed = false;
int n = 0, r;
assert(fd >= 0);
/*
* Sets up the specified subvolume's qgroup automatically in
* one of two ways:
*
* If insert_intermediary_qgroup is false, the subvolume's
* leaf qgroup will be assigned to the same parent qgroups as
* the subvolume's parent subvolume.
*
* If insert_intermediary_qgroup is true a new intermediary
* higher-level qgroup is created, with a higher level number,
* but reusing the id of the subvolume. The level number is
* picked as one smaller than the lowest level qgroup the
* parent subvolume is a member of. If the parent subvolume's
* leaf qgroup is assigned to no higher-level qgroup a new
* qgroup of level 255 is created instead. Either way, the new
* qgroup is then assigned to the parent's higher-level
* qgroup, and the subvolume itself is assigned to it.
*
* If the subvolume is already assigned to a higher level
* qgroup, no operation is executed.
*
* Effectively this means: regardless if
* insert_intermediary_qgroup is true or not, after this
* function is invoked the subvolume will be accounted within
* the same qgroups as the parent. However, if it is true, it
* will also get its own higher-level qgroup, which may in
* turn be used by subvolumes created beneath this subvolume
* later on.
*
* This hence defines a simple default qgroup setup for
* subvolumes, as long as this function is invoked on each
* created subvolume: each subvolume is always accounting
* together with its immediate parents. Optionally, if
* insert_intermediary_qgroup is true, it will also get a
* qgroup that then includes all its own child subvolumes.
*/
/* Turn this into a proper fd, if it is currently O_PATH */
fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC, O_PATH, &real_fd);
if (fd < 0)
return fd;
if (subvol_id == 0) {
r = btrfs_is_subvol_fd(fd);
if (r < 0)
return r;
if (!r)
return -ENOTTY;
r = btrfs_subvol_get_id_fd(fd, &subvol_id);
if (r < 0)
return r;
}
n = btrfs_qgroup_find_parents(fd, subvol_id, &qgroups);
if (n < 0)
return n;
if (n > 0) /* already parent qgroups set up, let's bail */
return 0;
qgroups = mfree(qgroups);
r = btrfs_subvol_get_parent(fd, subvol_id, &parent_subvol);
if (r == -ENXIO)
/* No parent, hence no qgroup memberships */
n = 0;
else if (r < 0)
return r;
else {
n = btrfs_qgroup_find_parents(fd, parent_subvol, &qgroups);
if (n < 0)
return n;
}
if (insert_intermediary_qgroup) {
uint64_t lowest = 256, new_qgroupid;
bool created = false;
/* Determine the lowest qgroup that the parent
* subvolume is assigned to. */
for (int i = 0; i < n; i++) {
uint64_t level;
r = btrfs_qgroupid_split(qgroups[i], &level, NULL);
if (r < 0)
return r;
if (level < lowest)
lowest = level;
}
if (lowest <= 1) /* There are no levels left we could use insert an intermediary qgroup at */
return -EBUSY;
r = btrfs_qgroupid_make(lowest - 1, subvol_id, &new_qgroupid);
if (r < 0)
return r;
/* Create the new intermediary group, unless it already exists */
r = btrfs_qgroup_create(fd, new_qgroupid);
if (r < 0 && r != -EEXIST)
return r;
if (r >= 0)
changed = created = true;
for (int i = 0; i < n; i++) {
r = btrfs_qgroup_assign(fd, new_qgroupid, qgroups[i]);
if (r < 0 && r != -EEXIST) {
if (created)
(void) btrfs_qgroup_destroy_recursive(fd, new_qgroupid);
return r;
}
if (r >= 0)
changed = true;
}
r = btrfs_qgroup_assign(fd, subvol_id, new_qgroupid);
if (r < 0 && r != -EEXIST) {
if (created)
(void) btrfs_qgroup_destroy_recursive(fd, new_qgroupid);
return r;
}
if (r >= 0)
changed = true;
} else {
int i;
/* Assign our subvolume to all the same qgroups as the parent */
for (i = 0; i < n; i++) {
r = btrfs_qgroup_assign(fd, subvol_id, qgroups[i]);
if (r < 0 && r != -EEXIST)
return r;
if (r >= 0)
changed = true;
}
}
return changed;
}
int btrfs_subvol_auto_qgroup(const char *path, uint64_t subvol_id, bool create_intermediary_qgroup) {
_cleanup_close_ int fd = -EBADF;
fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (fd < 0)
return -errno;
return btrfs_subvol_auto_qgroup_fd(fd, subvol_id, create_intermediary_qgroup);
}
int btrfs_subvol_make_default(const char *path) {
_cleanup_close_ int fd = -EBADF;
uint64_t id;
int r;
assert(path);
fd = open(path, O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (fd < 0)
return -errno;
r = btrfs_subvol_get_id_fd(fd, &id);
if (r < 0)
return r;
return RET_NERRNO(ioctl(fd, BTRFS_IOC_DEFAULT_SUBVOL, &id));
}
int btrfs_subvol_get_parent(int fd, uint64_t subvol_id, uint64_t *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_BACKREF_KEY,
.key.max_type = BTRFS_ROOT_BACKREF_KEY,
/* No restrictions on the other components */
.key.min_offset = 0,
.key.max_offset = UINT64_MAX,
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
int r;
assert(fd >= 0);
assert(ret);
if (subvol_id == 0) {
r = btrfs_subvol_get_id_fd(fd, &subvol_id);
if (r < 0)
return r;
} else {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
}
args.key.min_objectid = args.key.max_objectid = subvol_id;
while (btrfs_ioctl_search_args_compare(&args) <= 0) {
struct btrfs_ioctl_search_header sh;
_unused_ const void *body = NULL;
args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
return negative_errno();
if (args.key.nr_items <= 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, args) {
if (sh.type != BTRFS_ROOT_BACKREF_KEY)
continue;
if (sh.objectid != subvol_id)
continue;
*ret = sh.offset;
return 0;
}
}
return -ENXIO;
}
bool btrfs_might_be_subvol(const struct stat *st) {
if (!st)
return false;
/* Returns true if this 'struct stat' looks like it could refer to a btrfs subvolume. To make a final
* decision, needs to be combined with an fstatfs() check to see if this is actually btrfs. */
return S_ISDIR(st->st_mode) && st->st_ino == 256;
}
int btrfs_forget_device(const char *path) {
_cleanup_close_ int control_fd = -EBADF;
struct btrfs_ioctl_vol_args args = {};
assert(path);
if (strlen(path) > BTRFS_PATH_NAME_MAX)
return -E2BIG;
strcpy(args.name, path);
control_fd = open("/dev/btrfs-control", O_RDWR|O_CLOEXEC);
if (control_fd < 0)
return -errno;
return RET_NERRNO(ioctl(control_fd, BTRFS_IOC_FORGET_DEV, &args));
}
typedef struct BtrfsStripe {
uint64_t devid;
uint64_t offset;
} BtrfsStripe;
typedef struct BtrfsChunk {
uint64_t offset;
uint64_t length;
uint64_t type;
BtrfsStripe *stripes;
uint16_t n_stripes;
uint64_t stripe_len;
} BtrfsChunk;
typedef struct BtrfsChunkTree {
BtrfsChunk **chunks;
size_t n_chunks;
} BtrfsChunkTree;
static BtrfsChunk* btrfs_chunk_free(BtrfsChunk *chunk) {
if (!chunk)
return NULL;
free(chunk->stripes);
return mfree(chunk);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(BtrfsChunk*, btrfs_chunk_free);
static void btrfs_chunk_tree_done(BtrfsChunkTree *tree) {
assert(tree);
FOREACH_ARRAY(i, tree->chunks, tree->n_chunks)
btrfs_chunk_free(*i);
free(tree->chunks);
}
static int btrfs_read_chunk_tree_fd(int fd, BtrfsChunkTree *ret) {
struct btrfs_ioctl_search_args search_args = {
.key.tree_id = BTRFS_CHUNK_TREE_OBJECTID,
.key.min_type = BTRFS_CHUNK_ITEM_KEY,
.key.max_type = BTRFS_CHUNK_ITEM_KEY,
.key.min_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID,
.key.max_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID,
.key.min_offset = 0,
.key.max_offset = UINT64_MAX,
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
_cleanup_(btrfs_chunk_tree_done) BtrfsChunkTree tree = {};
assert(fd >= 0);
assert(ret);
while (btrfs_ioctl_search_args_compare(&search_args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
search_args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_args) < 0)
return -errno;
if (search_args.key.nr_items == 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, search_args) {
_cleanup_(btrfs_chunk_freep) BtrfsChunk *chunk = NULL;
btrfs_ioctl_search_args_set(&search_args, &sh);
if (sh.objectid != BTRFS_FIRST_CHUNK_TREE_OBJECTID)
continue;
if (sh.type != BTRFS_CHUNK_ITEM_KEY)
continue;
chunk = new(BtrfsChunk, 1);
if (!chunk)
return -ENOMEM;
const struct btrfs_chunk *item = body;
*chunk = (BtrfsChunk) {
.offset = sh.offset,
.length = le64toh(item->length),
.type = le64toh(item->type),
.n_stripes = le16toh(item->num_stripes),
.stripe_len = le64toh(item->stripe_len),
};
chunk->stripes = new(BtrfsStripe, chunk->n_stripes);
if (!chunk->stripes)
return -ENOMEM;
for (size_t j = 0; j < chunk->n_stripes; j++) {
const struct btrfs_stripe *stripe = &item->stripe + j;
chunk->stripes[j] = (BtrfsStripe) {
.devid = le64toh(stripe->devid),
.offset = le64toh(stripe->offset),
};
}
if (!GREEDY_REALLOC(tree.chunks, tree.n_chunks + 1))
return -ENOMEM;
tree.chunks[tree.n_chunks++] = TAKE_PTR(chunk);
}
if (!btrfs_ioctl_search_args_inc(&search_args))
break;
}
*ret = TAKE_STRUCT(tree);
return 0;
}
static BtrfsChunk* btrfs_find_chunk_from_logical_address(const BtrfsChunkTree *tree, uint64_t logical) {
size_t min_index, max_index;
assert(tree);
assert(tree->chunks || tree->n_chunks == 0);
if (tree->n_chunks == 0)
return NULL;
/* bisection */
min_index = 0;
max_index = tree->n_chunks - 1;
while (min_index <= max_index) {
size_t mid = (min_index + max_index) / 2;
if (logical < tree->chunks[mid]->offset) {
if (mid < 1)
return NULL;
max_index = mid - 1;
} else if (logical >= tree->chunks[mid]->offset + tree->chunks[mid]->length)
min_index = mid + 1;
else
return tree->chunks[mid];
}
return NULL;
}
static int btrfs_is_nocow_fd(int fd) {
unsigned flags;
int r;
assert(fd >= 0);
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r == 0)
return -ENOTTY;
r = read_attr_fd(fd, &flags);
if (r < 0)
return r;
return FLAGS_SET(flags, FS_NOCOW_FL) && !FLAGS_SET(flags, FS_COMPR_FL);
}
int btrfs_get_file_physical_offset_fd(int fd, uint64_t *ret) {
struct btrfs_ioctl_search_args search_args = {
.key.min_type = BTRFS_EXTENT_DATA_KEY,
.key.max_type = BTRFS_EXTENT_DATA_KEY,
.key.min_offset = 0,
.key.max_offset = UINT64_MAX,
.key.min_transid = 0,
.key.max_transid = UINT64_MAX,
};
_cleanup_(btrfs_chunk_tree_done) BtrfsChunkTree tree = {};
uint64_t subvol_id;
struct stat st;
int r;
assert(fd >= 0);
assert(ret);
if (fstat(fd, &st) < 0)
return -errno;
r = stat_verify_regular(&st);
if (r < 0)
return r;
r = btrfs_is_nocow_fd(fd);
if (r < 0)
return r;
if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: CoW enabled");
r = btrfs_subvol_get_id_fd(fd, &subvol_id);
if (r < 0)
return r;
r = btrfs_read_chunk_tree_fd(fd, &tree);
if (r < 0)
return r;
search_args.key.tree_id = subvol_id;
search_args.key.min_objectid = search_args.key.max_objectid = st.st_ino;
while (btrfs_ioctl_search_args_compare(&search_args) <= 0) {
struct btrfs_ioctl_search_header sh;
const void *body;
search_args.key.nr_items = 256;
if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_args) < 0)
return -errno;
if (search_args.key.nr_items == 0)
break;
FOREACH_BTRFS_IOCTL_SEARCH_HEADER(sh, body, search_args) {
uint64_t logical_offset;
BtrfsChunk *chunk;
btrfs_ioctl_search_args_set(&search_args, &sh);
if (sh.type != BTRFS_EXTENT_DATA_KEY)
continue;
if (sh.objectid != st.st_ino)
continue;
const struct btrfs_file_extent_item *item = body;
if (!IN_SET(item->type, BTRFS_FILE_EXTENT_REG, BTRFS_FILE_EXTENT_PREALLOC))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: invalid type %" PRIu8,
item->type);
if (item->compression != 0 || item->encryption != 0 || item->other_encoding != 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: has incompatible property");
logical_offset = le64toh(item->disk_bytenr);
if (logical_offset == 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: failed to get logical offset");
chunk = btrfs_find_chunk_from_logical_address(&tree, logical_offset);
if (!chunk)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: no matching chunk found");
if ((chunk->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) != 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Cannot get physical address for btrfs extent: unsupported profile");
uint64_t relative_chunk, relative_stripe, stripe_nr;
uint16_t stripe_index;
assert(logical_offset >= chunk->offset);
assert(chunk->n_stripes > 0);
assert(chunk->stripe_len > 0);
relative_chunk = logical_offset - chunk->offset;
stripe_nr = relative_chunk / chunk->stripe_len;
relative_stripe = relative_chunk - stripe_nr * chunk->stripe_len;
stripe_index = stripe_nr % chunk->n_stripes;
*ret = chunk->stripes[stripe_index].offset +
stripe_nr / chunk->n_stripes * chunk->stripe_len +
relative_stripe;
return 0;
}
if (!btrfs_ioctl_search_args_inc(&search_args))
break;
}
return -ENODATA;
}
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