chiark / gitweb /
qcow2: when dissecting qcow2, use btrfs clone ioctls for reflinking blocks to target
[elogind.git] / src / shared / btrfs-util.c
index d685b3ecbd23b12f9341974d0a8c6348bdfd7036..254483c31a3ce5649fc0d722456c448a5461d450 100644 (file)
@@ -33,6 +33,9 @@
 #include "macro.h"
 #include "strv.h"
 #include "copy.h"
+#include "selinux-util.h"
+#include "smack-util.h"
+#include "btrfs-ctree.h"
 #include "btrfs-util.h"
 
 static int validate_subvolume_name(const char *name) {
@@ -129,7 +132,7 @@ int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_
                         }
 
                         if (read_only) {
-                                r = btrfs_subvol_read_only(new_path, true);
+                                r = btrfs_subvol_set_read_only(new_path, true);
                                 if (r < 0) {
                                         btrfs_subvol_remove(new_path);
                                         return r;
@@ -183,6 +186,24 @@ int btrfs_subvol_make(const char *path) {
         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_remove(const char *path) {
         struct btrfs_ioctl_vol_args args = {};
         _cleanup_close_ int fd = -1;
@@ -207,7 +228,7 @@ int btrfs_subvol_remove(const char *path) {
         return 0;
 }
 
-int btrfs_subvol_read_only(const char *path, bool b) {
+int btrfs_subvol_set_read_only(const char *path, bool b) {
         _cleanup_close_ int fd = -1;
         uint64_t flags, nflags;
 
@@ -232,7 +253,7 @@ int btrfs_subvol_read_only(const char *path, bool b) {
         return 0;
 }
 
-int btrfs_subvol_is_read_only_fd(int fd) {
+int btrfs_subvol_get_read_only_fd(int fd) {
         uint64_t flags;
 
         if (ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags) < 0)
@@ -254,6 +275,26 @@ int btrfs_reflink(int infd, int outfd) {
         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,
+        };
+        int r;
+
+        assert(infd >= 0);
+        assert(outfd >= 0);
+        assert(sz > 0);
+
+        r = ioctl(outfd, BTRFS_IOC_CLONE_RANGE, &args);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
 int btrfs_get_block_device(const char *path, dev_t *dev) {
         struct btrfs_ioctl_fs_info_args fsi = {};
         _cleanup_close_ int fd = -1;
@@ -301,3 +342,294 @@ int btrfs_get_block_device(const char *path, dev_t *dev) {
 
         return -ENODEV;
 }
+
+int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
+        struct btrfs_ioctl_ino_lookup_args args = {
+                .objectid = BTRFS_FIRST_FREE_OBJECTID
+        };
+
+        assert(fd >= 0);
+        assert(ret);
+
+        if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args) < 0)
+                return -errno;
+
+        *ret = args.treeid;
+        return 0;
+}
+
+static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) {
+        assert(args);
+
+        /* the objectid, type, offset together make up the btrfs key,
+         * which is considered a single 136byte integer when
+         * comparing. This call increases the counter by one, dealing
+         * with the overflow between the overflows */
+
+        if (args->key.min_offset < (uint64_t) -1) {
+                args->key.min_offset++;
+                return true;
+        }
+
+        if (args->key.min_type < (uint8_t) -1) {
+                args->key.min_type++;
+                args->key.min_offset = 0;
+                return true;
+        }
+
+        if (args->key.min_objectid < (uint64_t) -1) {
+                args->key.min_objectid++;
+                args->key.min_offset = 0;
+                args->key.min_type = 0;
+                return true;
+        }
+
+        return 0;
+}
+
+static void btrfs_ioctl_search_args_set(struct btrfs_ioctl_search_args *args, const struct btrfs_ioctl_search_header *h) {
+        assert(args);
+        assert(h);
+
+        args->key.min_objectid = h->objectid;
+        args->key.min_type = h->type;
+        args->key.min_offset = h->offset;
+}
+
+static int btrfs_ioctl_search_args_compare(const struct btrfs_ioctl_search_args *args) {
+        assert(args);
+
+        /* Compare min and max */
+
+        if (args->key.min_objectid < args->key.max_objectid)
+                return -1;
+        if (args->key.min_objectid > args->key.max_objectid)
+                return 1;
+
+        if (args->key.min_type < args->key.max_type)
+                return -1;
+        if (args->key.min_type > args->key.max_type)
+                return 1;
+
+        if (args->key.min_offset < args->key.max_offset)
+                return -1;
+        if (args->key.min_offset > args->key.max_offset)
+                return 1;
+
+        return 0;
+}
+
+#define FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args)                  \
+        for ((i) = 0,                                                   \
+             (sh) = (const struct btrfs_ioctl_search_header*) (args).buf; \
+             (i) < (args).key.nr_items;                                 \
+             (i)++,                                                     \
+             (sh) = (const struct btrfs_ioctl_search_header*) ((uint8_t*) (sh) + sizeof(struct btrfs_ioctl_search_header) + (sh)->len))
+
+#define BTRFS_IOCTL_SEARCH_HEADER_BODY(sh)                              \
+        ((void*) ((uint8_t*) sh + sizeof(struct btrfs_ioctl_search_header)))
+
+int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *ret) {
+        struct btrfs_ioctl_search_args args = {
+                /* Tree of tree roots */
+                .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
+
+                /* Look precisely for the subvolume items */
+                .key.min_type = BTRFS_ROOT_ITEM_KEY,
+                .key.max_type = BTRFS_ROOT_ITEM_KEY,
+
+                .key.min_offset = 0,
+                .key.max_offset = (uint64_t) -1,
+
+                /* No restrictions on the other components */
+                .key.min_transid = 0,
+                .key.max_transid = (uint64_t) -1,
+        };
+
+        uint64_t subvol_id;
+        bool found = false;
+        int r;
+
+        assert(fd >= 0);
+        assert(ret);
+
+        r = btrfs_subvol_get_id_fd(fd, &subvol_id);
+        if (r < 0)
+                return r;
+
+        args.key.min_objectid = args.key.max_objectid = subvol_id;
+
+        while (btrfs_ioctl_search_args_compare(&args) <= 0) {
+                const struct btrfs_ioctl_search_header *sh;
+                unsigned i;
+
+                args.key.nr_items = 256;
+                if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
+                        return -errno;
+
+                if (args.key.nr_items <= 0)
+                        break;
+
+                FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
+
+                        const struct btrfs_root_item *ri;
+
+                        /* Make sure we start the next search at least from this entry */
+                        btrfs_ioctl_search_args_set(&args, sh);
+
+                        if (sh->objectid != subvol_id)
+                                continue;
+                        if (sh->type != BTRFS_ROOT_ITEM_KEY)
+                                continue;
+
+                        /* Older versions of the struct lacked the otime setting */
+                        if (sh->len < offsetof(struct btrfs_root_item, otime) + sizeof(struct btrfs_timespec))
+                                continue;
+
+                        ri = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
+
+                        ret->otime = (usec_t) le64toh(ri->otime.sec) * USEC_PER_SEC +
+                                (usec_t) le32toh(ri->otime.nsec) / NSEC_PER_USEC;
+
+                        ret->subvol_id = subvol_id;
+                        ret->read_only = !!(le64toh(ri->flags) & BTRFS_ROOT_SUBVOL_RDONLY);
+
+                        assert_cc(sizeof(ri->uuid) == sizeof(ret->uuid));
+                        memcpy(&ret->uuid, ri->uuid, sizeof(ret->uuid));
+                        memcpy(&ret->parent_uuid, ri->parent_uuid, sizeof(ret->parent_uuid));
+
+                        found = true;
+                        goto finish;
+                }
+
+                /* Increase search key by one, to read the next item, if we can. */
+                if (!btrfs_ioctl_search_args_inc(&args))
+                        break;
+        }
+
+finish:
+        if (!found)
+                return -ENODATA;
+
+        return 0;
+}
+
+int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) {
+
+        struct btrfs_ioctl_search_args args = {
+                /* Tree of quota items */
+                .key.tree_id = BTRFS_QUOTA_TREE_OBJECTID,
+
+                /* The object ID is always 0 */
+                .key.min_objectid = 0,
+                .key.max_objectid = 0,
+
+                /* Look precisely for the quota items */
+                .key.min_type = BTRFS_QGROUP_STATUS_KEY,
+                .key.max_type = BTRFS_QGROUP_LIMIT_KEY,
+
+                /* No restrictions on the other components */
+                .key.min_transid = 0,
+                .key.max_transid = (uint64_t) -1,
+        };
+
+        uint64_t subvol_id;
+        bool found_info = false, found_limit = false;
+        int r;
+
+        assert(fd >= 0);
+        assert(ret);
+
+        r = btrfs_subvol_get_id_fd(fd, &subvol_id);
+        if (r < 0)
+                return r;
+
+        args.key.min_offset = args.key.max_offset = subvol_id;
+
+        while (btrfs_ioctl_search_args_compare(&args) <= 0) {
+                const struct btrfs_ioctl_search_header *sh;
+                unsigned i;
+
+                args.key.nr_items = 256;
+                if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
+                        return -errno;
+
+                if (args.key.nr_items <= 0)
+                        break;
+
+                FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
+
+                        /* Make sure we start the next search at least from this entry */
+                        btrfs_ioctl_search_args_set(&args, sh);
+
+                        if (sh->objectid != 0)
+                                continue;
+                        if (sh->offset != subvol_id)
+                                continue;
+
+                        if (sh->type == BTRFS_QGROUP_INFO_KEY) {
+                                const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
+
+                                ret->referred = le64toh(qii->rfer);
+                                ret->exclusive = le64toh(qii->excl);
+
+                                found_info = true;
+
+                        } else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
+                                const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
+
+                                ret->referred_max = le64toh(qli->max_rfer);
+                                ret->exclusive_max = le64toh(qli->max_excl);
+
+                                if (ret->referred_max == 0)
+                                        ret->referred_max = (uint64_t) -1;
+                                if (ret->exclusive_max == 0)
+                                        ret->exclusive_max = (uint64_t) -1;
+
+                                found_limit = true;
+                        }
+
+                        if (found_info && found_limit)
+                                goto finish;
+                }
+
+                /* Increase search key by one, to read the next item, if we can. */
+                if (!btrfs_ioctl_search_args_inc(&args))
+                        break;
+        }
+
+finish:
+        if (!found_limit && !found_info)
+                return -ENODATA;
+
+        if (!found_info) {
+                ret->referred = (uint64_t) -1;
+                ret->exclusive = (uint64_t) -1;
+        }
+
+        if (!found_limit) {
+                ret->referred_max = (uint64_t) -1;
+                ret->exclusive_max = (uint64_t) -1;
+        }
+
+        return 0;
+}
+
+int btrfs_defrag_fd(int fd) {
+        assert(fd >= 0);
+
+        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);
+}