Merge pull request #1641 from poettering/btrfs-quota

btrfs quota beef up and various other unrelated changes

8 files changed, 944 insertions, 91 deletions

diff --git a/src/basic/btrfs-util.c b/src/basic/btrfs-util.c
index ec7e00986b..f327c16a80 100644
--- a/src/basic/btrfs-util.c
+++ b/src/basic/btrfs-util.c
@@ -436,7 +436,7 @@ static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args
 #define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh)                              \
         ((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
 
-int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
+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,
@@ -453,16 +453,23 @@ int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
                 .key.max_transid = (uint64_t) -1,
         };
 
-        uint64_t subvol_id;
         bool found = false;
         int r;
 
         assert(fd >= 0);
         assert(ret);
 
-        r = btrfs_subvol_get_id_fd(fd, &subvol_id);
-        if (r < 0)
-                return r;
+        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;
 
@@ -521,7 +528,7 @@ finish:
         return 0;
 }
 
-int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
+int btrfs_qgroup_get_quota_fd(int fd, uint64_t qgroupid, BtrfsQuotaInfo *ret) {
 
         struct btrfs_ioctl_search_args args = {
                 /* Tree of quota items */
@@ -540,18 +547,25 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
                 .key.max_transid = (uint64_t) -1,
         };
 
-        uint64_t subvol_id;
         bool found_info = false, found_limit = false;
         int r;
 
         assert(fd >= 0);
         assert(ret);
 
-        r = btrfs_subvol_get_id_fd(fd, &subvol_id);
-        if (r < 0)
-                return r;
+        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 = subvol_id;
+        args.key.min_offset = args.key.max_offset = qgroupid;
 
         while (btrfs_ioctl_search_args_compare(&args) <= 0) {
                 const struct btrfs_ioctl_search_header *sh;
@@ -571,7 +585,7 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
 
                         if (sh->objectid != 0)
                                 continue;
-                        if (sh->offset != subvol_id)
+                        if (sh->offset != qgroupid)
                                 continue;
 
                         if (sh->type == BTRFS_QGROUP_INFO_KEY) {
@@ -585,12 +599,14 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
                         } else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
                                 const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
 
-                                ret->referenced_max = le64toh(qli->max_rfer);
-                                ret->exclusive_max = le64toh(qli->max_excl);
-
-                                if (ret->referenced_max == 0)
+                                if (le64toh(qli->flags) & BTRFS_QGROUP_LIMIT_MAX_RFER)
+                                        ret->referenced_max = le64toh(qli->max_rfer);
+                                else
                                         ret->referenced_max = (uint64_t) -1;
-                                if (ret->exclusive_max == 0)
+
+                                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;
@@ -622,6 +638,109 @@ finish:
         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;
 
@@ -679,37 +798,79 @@ int btrfs_quota_enable(const char *path, bool b) {
         return btrfs_quota_enable_fd(fd, b);
 }
 
-int btrfs_quota_limit_fd(int fd, uint64_t referenced_max) {
+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 == (uint64_t) -1 ? 0 :
-                        referenced_max == 0 ? 1 : referenced_max,
+                .lim.max_rfer = referenced_max,
                 .lim.flags = BTRFS_QGROUP_LIMIT_MAX_RFER,
         };
+        unsigned c;
         int r;
 
         assert(fd >= 0);
 
-        r = btrfs_is_filesystem(fd);
-        if (r < 0)
-                return r;
-        if (!r)
-                return -ENOTTY;
+        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;
+        }
 
-        if (ioctl(fd, BTRFS_IOC_QGROUP_LIMIT, &args) < 0)
-                return -errno;
+        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_quota_limit(const char *path, uint64_t referenced_max) {
+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_quota_limit_fd(fd, referenced_max);
+        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) {
@@ -799,7 +960,7 @@ int btrfs_resize_loopback(const char *p, uint64_t new_size, bool grow_only) {
         return btrfs_resize_loopback_fd(fd, new_size, grow_only);
 }
 
-static int make_qgroup_id(uint64_t level, uint64_t id, uint64_t *ret) {
+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)))
@@ -812,33 +973,175 @@ static int make_qgroup_id(uint64_t level, uint64_t id, uint64_t *ret) {
         return 0;
 }
 
-static int qgroup_create_or_destroy(int fd, bool b, uint64_t level, uint64_t id) {
+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 = make_qgroup_id(level, id, (uint64_t*) &args.qgroupid);
+        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;
+                }
 
-        if (ioctl(fd, BTRFS_IOC_QGROUP_CREATE, &args) < 0)
+                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_qgroup_create(int fd, uint64_t level, uint64_t id) {
-        return qgroup_create_or_destroy(fd, true, level, id);
+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_qgroup_destroy(int fd, uint64_t level, uint64_t id) {
-        return qgroup_create_or_destroy(fd, false, level, id);
+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 subvol_remove_children(int fd, const char *subvolume, uint64_t subvol_id, bool recursive) {
+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,
 
@@ -881,10 +1184,10 @@ static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol
          * 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(fd, 0, subvol_id);
+                (void) btrfs_qgroup_destroy_recursive(fd, subvol_id); /* for the leaf subvolumes, the qgroup id is identical to the subvol id */
                 return 0;
         }
-        if (!recursive || errno != ENOTEMPTY)
+        if (!(flags & BTRFS_REMOVE_RECURSIVE) || errno != ENOTEMPTY)
                 return -errno;
 
         /* OK, the subvolume is not empty, let's look for child
@@ -939,7 +1242,7 @@ static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol
                         if (isempty(ino_args.name))
                                 /* Subvolume is in the top-level
                                  * directory of the subvolume. */
-                                r = subvol_remove_children(subvol_fd, p, sh->objectid, recursive);
+                                r = subvol_remove_children(subvol_fd, p, sh->objectid, flags);
                         else {
                                 _cleanup_close_ int child_fd = -1;
 
@@ -951,7 +1254,7 @@ static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol
                                 if (child_fd < 0)
                                         return -errno;
 
-                                r = subvol_remove_children(child_fd, p, sh->objectid, recursive);
+                                r = subvol_remove_children(child_fd, p, sh->objectid, flags);
                         }
                         if (r < 0)
                                 return r;
@@ -967,11 +1270,11 @@ static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol
         if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) < 0)
                 return -errno;
 
-        (void) btrfs_qgroup_destroy(fd, 0, subvol_id);
+        (void) btrfs_qgroup_destroy_recursive(fd, subvol_id);
         return 0;
 }
 
-int btrfs_subvol_remove(const char *path, bool recursive) {
+int btrfs_subvol_remove(const char *path, BtrfsRemoveFlags flags) {
         _cleanup_close_ int fd = -1;
         const char *subvolume;
         int r;
@@ -986,11 +1289,194 @@ int btrfs_subvol_remove(const char *path, bool recursive) {
         if (fd < 0)
                 return fd;
 
-        return subvol_remove_children(fd, subvolume, 0, recursive);
+        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;
 }
 
-int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive) {
-        return subvol_remove_children(fd, subvolume, 0, recursive);
+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) {
@@ -1021,12 +1507,12 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum
         assert(subvolume);
 
         strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
-        vol_args.fd = old_fd;
 
         if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &vol_args) < 0)
                 return -errno;
 
-        if (!(flags & BTRFS_SNAPSHOT_RECURSIVE))
+        if (!(flags & BTRFS_SNAPSHOT_RECURSIVE) &&
+            !(flags & BTRFS_SNAPSHOT_QUOTA))
                 return 0;
 
         if (old_subvol_id == 0) {
@@ -1039,6 +1525,17 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum
         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) {
@@ -1156,6 +1653,9 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum
                         break;
         }
 
+        if (flags & BTRFS_SNAPSHOT_QUOTA)
+                (void) copy_subtree_quota_limits(new_fd, old_subvol_id, new_subvol_id);
+
         return 0;
 }
 
@@ -1180,14 +1680,14 @@ int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlag
 
                 r = copy_directory_fd(old_fd, new_path, true);
                 if (r < 0) {
-                        btrfs_subvol_remove(new_path, false);
+                        (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) {
-                                btrfs_subvol_remove(new_path, false);
+                                (void) btrfs_subvol_remove(new_path, BTRFS_REMOVE_QUOTA);
                                 return r;
                         }
                 }
@@ -1218,3 +1718,302 @@ int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnaps
 
         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;
+}
diff --git a/src/basic/btrfs-util.h b/src/basic/btrfs-util.h
index ad7c7009ab..fc9efd72d5 100644
--- a/src/basic/btrfs-util.h
+++ b/src/basic/btrfs-util.h
@@ -47,45 +47,82 @@ typedef enum BtrfsSnapshotFlags {
         BTRFS_SNAPSHOT_FALLBACK_COPY = 1,
         BTRFS_SNAPSHOT_READ_ONLY = 2,
         BTRFS_SNAPSHOT_RECURSIVE = 4,
+        BTRFS_SNAPSHOT_QUOTA = 8,
 } BtrfsSnapshotFlags;
 
+typedef enum BtrfsRemoveFlags {
+        BTRFS_REMOVE_RECURSIVE = 1,
+        BTRFS_REMOVE_QUOTA = 2,
+} BtrfsRemoveFlags;
+
 int btrfs_is_filesystem(int fd);
 int btrfs_is_subvol(int fd);
 
+int btrfs_reflink(int infd, int outfd);
+int btrfs_clone_range(int infd, uint64_t in_offset, int ofd, uint64_t out_offset, uint64_t sz);
+
+int btrfs_get_block_device_fd(int fd, dev_t *dev);
+int btrfs_get_block_device(const char *path, dev_t *dev);
+
+int btrfs_defrag_fd(int fd);
+int btrfs_defrag(const char *p);
+
+int btrfs_quota_enable_fd(int fd, bool b);
+int btrfs_quota_enable(const char *path, bool b);
+
+int btrfs_quota_scan_start(int fd);
+int btrfs_quota_scan_wait(int fd);
+int btrfs_quota_scan_ongoing(int fd);
+
+int btrfs_resize_loopback_fd(int fd, uint64_t size, bool grow_only);
+int btrfs_resize_loopback(const char *path, uint64_t size, bool grow_only);
+
 int btrfs_subvol_make(const char *path);
 int btrfs_subvol_make_label(const char *path);
 
 int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlags flags);
 int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnapshotFlags flags);
 
+int btrfs_subvol_remove(const char *path, BtrfsRemoveFlags flags);
+int btrfs_subvol_remove_fd(int fd, const char *subvolume, BtrfsRemoveFlags flags);
+
 int btrfs_subvol_set_read_only_fd(int fd, bool b);
 int btrfs_subvol_set_read_only(const char *path, bool b);
 int btrfs_subvol_get_read_only_fd(int fd);
+
 int btrfs_subvol_get_id(int fd, const char *subvolume, uint64_t *ret);
 int btrfs_subvol_get_id_fd(int fd, uint64_t *ret);
-int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *info);
-int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *quota);
+int btrfs_subvol_get_parent(int fd, uint64_t subvol_id, uint64_t *ret);
 
-int btrfs_reflink(int infd, int outfd);
-int btrfs_clone_range(int infd, uint64_t in_offset, int ofd, uint64_t out_offset, uint64_t sz);
+int btrfs_subvol_get_info_fd(int fd, uint64_t subvol_id, BtrfsSubvolInfo *info);
 
-int btrfs_get_block_device_fd(int fd, dev_t *dev);
-int btrfs_get_block_device(const char *path, dev_t *dev);
+int btrfs_subvol_find_subtree_qgroup(int fd, uint64_t subvol_id, uint64_t *ret);
 
-int btrfs_defrag_fd(int fd);
-int btrfs_defrag(const char *p);
+int btrfs_subvol_get_subtree_quota(const char *path, uint64_t subvol_id, BtrfsQuotaInfo *quota);
+int btrfs_subvol_get_subtree_quota_fd(int fd, uint64_t subvol_id, BtrfsQuotaInfo *quota);
 
-int btrfs_quota_enable_fd(int fd, bool b);
-int btrfs_quota_enable(const char *path, bool b);
+int btrfs_subvol_set_subtree_quota_limit(const char *path, uint64_t subvol_id, uint64_t referenced_max);
+int btrfs_subvol_set_subtree_quota_limit_fd(int fd, uint64_t subvol_id, uint64_t referenced_max);
 
-int btrfs_quota_limit_fd(int fd, uint64_t referenced_max);
-int btrfs_quota_limit(const char *path, uint64_t referenced_max);
+int btrfs_subvol_auto_qgroup_fd(int fd, uint64_t subvol_id, bool new_qgroup);
+int btrfs_subvol_auto_qgroup(const char *path, uint64_t subvol_id, bool create_intermediary_qgroup);
 
-int btrfs_resize_loopback_fd(int fd, uint64_t size, bool grow_only);
-int btrfs_resize_loopback(const char *path, uint64_t size, bool grow_only);
+int btrfs_qgroupid_make(uint64_t level, uint64_t id, uint64_t *ret);
+int btrfs_qgroupid_split(uint64_t qgroupid, uint64_t *level, uint64_t *id);
+
+int btrfs_qgroup_create(int fd, uint64_t qgroupid);
+int btrfs_qgroup_destroy(int fd, uint64_t qgroupid);
+int btrfs_qgroup_destroy_recursive(int fd, uint64_t qgroupid);
+
+int btrfs_qgroup_set_limit_fd(int fd, uint64_t qgroupid, uint64_t referenced_max);
+int btrfs_qgroup_set_limit(const char *path, uint64_t qgroupid, uint64_t referenced_max);
+
+int btrfs_qgroup_copy_limits(int fd, uint64_t old_qgroupid, uint64_t new_qgroupid);
+
+int btrfs_qgroup_assign(int fd, uint64_t child, uint64_t parent);
+int btrfs_qgroup_unassign(int fd, uint64_t child, uint64_t parent);
 
-int btrfs_subvol_remove(const char *path, bool recursive);
-int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive);
+int btrfs_qgroup_find_parents(int fd, uint64_t qgroupid, uint64_t **ret);
 
-int btrfs_qgroup_create(int fd, uint64_t level, uint64_t id);
-int btrfs_qgroup_destroy(int fd, uint64_t level, uint64_t id);
+int btrfs_qgroup_get_quota_fd(int fd, uint64_t qgroupid, BtrfsQuotaInfo *quota);
+int btrfs_qgroup_get_quota(const char *path, uint64_t qgroupid, BtrfsQuotaInfo *quota);
diff --git a/src/basic/missing.h b/src/basic/missing.h
index 70d6c8308e..306c56a156 100644
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -494,6 +494,10 @@ struct btrfs_ioctl_quota_ctl_args {
 #define BTRFS_QGROUP_LIMIT_KEY 244
 #endif
 
+#ifndef BTRFS_QGROUP_RELATION_KEY
+#define BTRFS_QGROUP_RELATION_KEY 246
+#endif
+
 #ifndef BTRFS_ROOT_BACKREF_KEY
 #define BTRFS_ROOT_BACKREF_KEY 144
 #endif
diff --git a/src/basic/path-util.c b/src/basic/path-util.c
index 5cbfc145a4..1039623305 100644
--- a/src/basic/path-util.c
+++ b/src/basic/path-util.c
@@ -796,14 +796,11 @@ bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool upd
         return changed;
 }
 
-int fsck_exists(const char *fstype) {
+static int binary_is_good(const char *binary) {
         _cleanup_free_ char *p = NULL, *d = NULL;
-        const char *checker;
         int r;
 
-        checker = strjoina("fsck.", fstype);
-
-        r = find_binary(checker, true, &p);
+        r = find_binary(binary, true, &p);
         if (r < 0)
                 return r;
 
@@ -820,6 +817,22 @@ int fsck_exists(const char *fstype) {
         return 0;
 }
 
+int fsck_exists(const char *fstype) {
+        const char *checker;
+
+        checker = strjoina("fsck.", fstype);
+
+        return binary_is_good(checker);
+}
+
+int mkfs_exists(const char *fstype) {
+        const char *mkfs;
+
+        mkfs = strjoina("mkfs.", fstype);
+
+        return binary_is_good(mkfs);
+}
+
 char *prefix_root(const char *root, const char *path) {
         char *n, *p;
         size_t l;
diff --git a/src/basic/path-util.h b/src/basic/path-util.h
index 1eac89c51b..71e25f1e57 100644
--- a/src/basic/path-util.h
+++ b/src/basic/path-util.h
@@ -63,6 +63,7 @@ int find_binary(const char *name, bool local, char **filename);
 bool paths_check_timestamp(const char* const* paths, usec_t *paths_ts_usec, bool update);
 
 int fsck_exists(const char *fstype);
+int mkfs_exists(const char *fstype);
 
 /* Iterates through the path prefixes of the specified path, going up
  * the tree, to root. Also returns "" (and not "/"!) for the root
diff --git a/src/basic/rm-rf.c b/src/basic/rm-rf.c
index dbbe817684..2ef63799d7 100644
--- a/src/basic/rm-rf.c
+++ b/src/basic/rm-rf.c
@@ -120,7 +120,7 @@ int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
 
                                 /* This could be a subvolume, try to remove it */
 
-                                r = btrfs_subvol_remove_fd(fd, de->d_name, true);
+                                r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
                                 if (r < 0) {
                                         if (r != -ENOTTY && r != -EINVAL) {
                                                 if (ret == 0)
@@ -178,7 +178,7 @@ int rm_rf(const char *path, RemoveFlags flags) {
 
         if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
                 /* Try to remove as subvolume first */
-                r = btrfs_subvol_remove(path, true);
+                r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
                 if (r >= 0)
                         return r;
 
diff --git a/src/basic/util.c b/src/basic/util.c
index 3989b415fa..ec3b360ffe 100644
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -2381,25 +2381,16 @@ bool is_device_path(const char *path) {
 
 int dir_is_empty(const char *path) {
         _cleanup_closedir_ DIR *d;
+        struct dirent *de;
 
         d = opendir(path);
         if (!d)
                 return -errno;
 
-        for (;;) {
-                struct dirent *de;
-
-                errno = 0;
-                de = readdir(d);
-                if (!de && errno != 0)
-                        return -errno;
-
-                if (!de)
-                        return 1;
+        FOREACH_DIRENT(de, d, return -errno)
+                return 0;
 
-                if (!hidden_file(de->d_name))
-                        return 0;
-        }
+        return 1;
 }
 
 char* dirname_malloc(const char *path) {
diff --git a/src/basic/util.h b/src/basic/util.h
index ff39eae715..a3ebb987e4 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -358,6 +358,14 @@ bool is_device_path(const char *path);
 int dir_is_empty(const char *path);
 char* dirname_malloc(const char *path);
 
+static inline int dir_is_populated(const char *path) {
+        int r;
+        r = dir_is_empty(path);
+        if (r < 0)
+                return r;
+        return !r;
+}
+
 char* lookup_uid(uid_t uid);
 char* getlogname_malloc(void);
 char* getusername_malloc(void);