/*-*- 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/stat.h> #include <sys/vfs.h> #ifdef HAVE_LINUX_BTRFS_H #include <linux/btrfs.h> #endif #include "alloc-util.h" #include "btrfs-ctree.h" #include "btrfs-util.h" #include "copy.h" #include "fd-util.h" #include "fileio.h" #include "macro.h" #include "missing.h" #include "path-util.h" #include "selinux-util.h" #include "smack-util.h" #include "stat-util.h" #include "string-util.h" #include "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 fd; assert(path); parent = dirname_malloc(path); if (!parent) return -ENOMEM; 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; } int btrfs_subvol_get_id(int fd, const char *subvol, uint64_t *ret) { _cleanup_close_ int subvol_fd = -1; 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_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, 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_t) -1, /* No restrictions on the other components */ .key.min_transid = 0, .key.max_transid = (uint64_t) -1, }; bool found = false; 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 = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; } 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_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_t) -1, }; 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 = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; } args.key.min_offset = args.key.max_offset = qgroupid; 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 != qgroupid) 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); if (le64toh(qli->flags) & BTRFS_QGROUP_LIMIT_MAX_RFER) ret->referenced_max = le64toh(qli->max_rfer); else ret->referenced_max = (uint64_t) -1; if (le64toh(qli->flags) & BTRFS_QGROUP_LIMIT_MAX_EXCL) ret->exclusive_max = le64toh(qli->max_excl); else 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_qgroup_get_quota(const char *path, uint64_t qgroupid, BtrfsQuotaInfo *ret) { _cleanup_close_ int fd = -1; 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_t) -1, lowest_qgroupid = 0; _cleanup_free_ uint64_t *qgroups = NULL; int r, n, i; 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 distuingished 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 (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_t) -1 || level < lowest) { lowest_qgroupid = qgroups[i]; lowest = level; } } if (lowest == (uint64_t) -1) { /* 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 = -1; 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) { 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_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, }; unsigned c; int r; assert(fd >= 0); if (qgroupid == 0) { r = btrfs_subvol_get_id_fd(fd, &qgroupid); if (r < 0) return r; } else { r = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; } args.qgroupid = qgroupid; for (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 = -1; 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 = -1; 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_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); } 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, }; unsigned c; int r; r = btrfs_is_filesystem(fd); if (r < 0) return r; if (r == 0) return -ENOTTY; for (c = 0;; c++) { if (ioctl(fd, BTRFS_IOC_QGROUP_CREATE, &args) < 0) { 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 i, n, r; /* Destroys the specified qgroup, but unassigns it from all * its parents first. Also, it recursively destroys all * qgroups it is assgined 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 (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); if (ioctl(fd, BTRFS_IOC_QUOTA_RESCAN, &args) < 0) return -errno; return 0; } int btrfs_quota_scan_wait(int fd) { assert(fd >= 0); if (ioctl(fd, BTRFS_IOC_QUOTA_RESCAN_WAIT) < 0) return -errno; return 0; } 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, }; unsigned c; int r; r = btrfs_is_filesystem(fd); if (r < 0) return r; if (r == 0) return -ENOTTY; for (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_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; 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; } /* 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) { 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, flags); 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, 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(const char *path, BtrfsRemoveFlags flags) { _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, flags); } int btrfs_subvol_remove_fd(int fd, const char *subvolume, BtrfsRemoveFlags flags) { 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_t) -1, }; int r; r = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; 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_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh); 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. */ 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, i; 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; r = btrfs_subvol_get_parent(fd, old_subvol_id, &old_parent_id); if (r < 0) return r; 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 (i = 0; i < n_old_qgroups; i++) { uint64_t id; int j; 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 (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_t) -1, }; 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 = -1; 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 & BTRFS_SNAPSHOT_RECURSIVE) && !(flags & BTRFS_SNAPSHOT_QUOTA)) return 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 0; } args.key.min_offset = args.key.max_offset = old_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; /* 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; 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 = old_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 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); /* 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 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) { (void) btrfs_subvol_remove(new_path, BTRFS_REMOVE_QUOTA); return r; } if (flags & BTRFS_SNAPSHOT_READ_ONLY) { r = btrfs_subvol_set_read_only(new_path, true); if (r < 0) { (void) btrfs_subvol_remove(new_path, BTRFS_REMOVE_QUOTA); 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); } 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_t) -1, .key.min_transid = 0, .key.max_transid = (uint64_t) -1, }; _cleanup_free_ uint64_t *items = NULL; size_t n_items = 0, n_allocated = 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 = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; } args.key.min_objectid = args.key.max_objectid = qgroupid; 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->type != BTRFS_QGROUP_RELATION_KEY) continue; if (sh->offset < sh->objectid) continue; if (sh->objectid != qgroupid) continue; if (!GREEDY_REALLOC(items, n_allocated, 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; } if (n_items <= 0) { *ret = NULL; return 0; } *ret = items; items = NULL; 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; 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. */ if (subvol_id == 0) { r = btrfs_is_subvol(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; r = btrfs_subvol_get_parent(fd, subvol_id, &parent_subvol); if (r < 0) return r; qgroups = mfree(qgroups); 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; int i; /* Determine the lowest qgroup that the parent * subvolume is assigned to. */ for (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 (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 = -1; 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_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_t) -1, .key.min_transid = 0, .key.max_transid = (uint64_t) -1, }; 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 = btrfs_is_filesystem(fd); if (r < 0) return r; if (!r) return -ENOTTY; } 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) { if (sh->type != BTRFS_ROOT_BACKREF_KEY) continue; if (sh->objectid != subvol_id) continue; *ret = sh->offset; return 0; } } return -ENXIO; }