* Boston, MA 021110-1307, USA.
*/
+#include <unistd.h>
+#include <fcntl.h>
#include <sys/ioctl.h>
+#include <uuid/uuid.h>
#include "ctree.h"
#include "send-utils.h"
static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
u64 subvol_id);
+static int btrfs_get_root_id_by_sub_path(int mnt_fd, const char *sub_path,
+ u64 *root_id)
+{
+ int ret;
+ int subvol_fd;
+
+ subvol_fd = openat(mnt_fd, sub_path, O_RDONLY);
+ if (subvol_fd < 0) {
+ ret = -errno;
+ fprintf(stderr, "ERROR: open %s failed. %s\n", sub_path,
+ strerror(-ret));
+ return ret;
+ }
+
+ ret = btrfs_list_get_path_rootid(subvol_fd, root_id);
+ close(subvol_fd);
+ return ret;
+}
+
+static int btrfs_read_root_item_raw(int mnt_fd, u64 root_id, size_t buf_len,
+ u32 *read_len, void *buf)
+{
+ int ret;
+ struct btrfs_ioctl_search_args args;
+ struct btrfs_ioctl_search_key *sk = &args.key;
+ struct btrfs_ioctl_search_header *sh;
+ unsigned long off = 0;
+ int found = 0;
+ int i;
+
+ *read_len = 0;
+ memset(&args, 0, sizeof(args));
+
+ sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+
+ /*
+ * there may be more than one ROOT_ITEM key if there are
+ * snapshots pending deletion, we have to loop through
+ * them.
+ */
+ sk->min_objectid = root_id;
+ sk->max_objectid = root_id;
+ sk->max_type = BTRFS_ROOT_ITEM_KEY;
+ sk->min_type = BTRFS_ROOT_ITEM_KEY;
+ sk->max_offset = (u64)-1;
+ sk->max_transid = (u64)-1;
+ sk->nr_items = 4096;
+
+ while (1) {
+ ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
+ if (ret < 0) {
+ fprintf(stderr,
+ "ERROR: can't perform the search - %s\n",
+ strerror(errno));
+ return 0;
+ }
+ /* the ioctl returns the number of item it found in nr_items */
+ if (sk->nr_items == 0)
+ break;
+
+ off = 0;
+ for (i = 0; i < sk->nr_items; i++) {
+ struct btrfs_root_item *item;
+ sh = (struct btrfs_ioctl_search_header *)(args.buf +
+ off);
+
+ off += sizeof(*sh);
+ item = (struct btrfs_root_item *)(args.buf + off);
+ off += sh->len;
+
+ sk->min_objectid = sh->objectid;
+ sk->min_type = sh->type;
+ sk->min_offset = sh->offset;
+
+ if (sh->objectid > root_id)
+ break;
+
+ if (sh->objectid == root_id &&
+ sh->type == BTRFS_ROOT_ITEM_KEY) {
+ if (sh->len > buf_len) {
+ /* btrfs-progs is too old for kernel */
+ fprintf(stderr,
+ "ERROR: buf for read_root_item_raw() is too small, get newer btrfs tools!\n");
+ return -EOVERFLOW;
+ }
+ memcpy(buf, item, sh->len);
+ *read_len = sh->len;
+ found = 1;
+ }
+ }
+ if (sk->min_offset < (u64)-1)
+ sk->min_offset++;
+ else
+ break;
+
+ if (sk->min_type != BTRFS_ROOT_ITEM_KEY ||
+ sk->min_objectid != root_id)
+ break;
+ }
+
+ return found ? 0 : -ENOENT;
+}
+
+/*
+ * Read a root item from the tree. In case we detect a root item smaller then
+ * sizeof(root_item), we know it's an old version of the root structure and
+ * initialize all new fields to zero. The same happens if we detect mismatching
+ * generation numbers as then we know the root was once mounted with an older
+ * kernel that was not aware of the root item structure change.
+ */
+static int btrfs_read_root_item(int mnt_fd, u64 root_id,
+ struct btrfs_root_item *item)
+{
+ int ret;
+ u32 read_len;
+
+ ret = btrfs_read_root_item_raw(mnt_fd, root_id, sizeof(*item),
+ &read_len, item);
+ if (ret)
+ return ret;
+
+ if (read_len < sizeof(*item) ||
+ btrfs_root_generation(item) != btrfs_root_generation_v2(item))
+ memset(&item->generation_v2, 0,
+ sizeof(*item) - offsetof(struct btrfs_root_item,
+ generation_v2));
+
+ return 0;
+}
+
int btrfs_subvolid_resolve(int fd, char *path, size_t path_len, u64 subvol_id)
{
if (path_len < 1)
return 0;
}
-static struct rb_node *tree_insert(struct rb_root *root,
- struct subvol_info *si,
- enum subvol_search_type type)
-{
- struct rb_node ** p = &root->rb_node;
- struct rb_node * parent = NULL;
- struct subvol_info *entry;
- __s64 comp;
-
- while(*p) {
- parent = *p;
- if (type == subvol_search_by_received_uuid) {
- entry = rb_entry(parent, struct subvol_info,
- rb_received_node);
-
- comp = memcmp(entry->received_uuid, si->received_uuid,
- BTRFS_UUID_SIZE);
- if (!comp) {
- if (entry->stransid < si->stransid)
- comp = -1;
- else if (entry->stransid > si->stransid)
- comp = 1;
- else
- comp = 0;
- }
- } else if (type == subvol_search_by_uuid) {
- entry = rb_entry(parent, struct subvol_info,
- rb_local_node);
- comp = memcmp(entry->uuid, si->uuid, BTRFS_UUID_SIZE);
- } else if (type == subvol_search_by_root_id) {
- entry = rb_entry(parent, struct subvol_info,
- rb_root_id_node);
- comp = entry->root_id - si->root_id;
- } else if (type == subvol_search_by_path) {
- entry = rb_entry(parent, struct subvol_info,
- rb_path_node);
- comp = strcmp(entry->path, si->path);
- } else {
- BUG();
- }
-
- if (comp < 0)
- p = &(*p)->rb_left;
- else if (comp > 0)
- p = &(*p)->rb_right;
- else
- return parent;
- }
-
- if (type == subvol_search_by_received_uuid) {
- rb_link_node(&si->rb_received_node, parent, p);
- rb_insert_color(&si->rb_received_node, root);
- } else if (type == subvol_search_by_uuid) {
- rb_link_node(&si->rb_local_node, parent, p);
- rb_insert_color(&si->rb_local_node, root);
- } else if (type == subvol_search_by_root_id) {
- rb_link_node(&si->rb_root_id_node, parent, p);
- rb_insert_color(&si->rb_root_id_node, root);
- } else if (type == subvol_search_by_path) {
- rb_link_node(&si->rb_path_node, parent, p);
- rb_insert_color(&si->rb_path_node, root);
- }
- return NULL;
-}
-
-static struct subvol_info *tree_search(struct rb_root *root,
- u64 root_id, const u8 *uuid,
- u64 stransid, const char *path,
- enum subvol_search_type type)
-{
- struct rb_node * n = root->rb_node;
- struct subvol_info *entry;
- __s64 comp;
-
- while(n) {
- if (type == subvol_search_by_received_uuid) {
- entry = rb_entry(n, struct subvol_info,
- rb_received_node);
- comp = memcmp(entry->received_uuid, uuid,
- BTRFS_UUID_SIZE);
- if (!comp) {
- if (entry->stransid < stransid)
- comp = -1;
- else if (entry->stransid > stransid)
- comp = 1;
- else
- comp = 0;
- }
- } else if (type == subvol_search_by_uuid) {
- entry = rb_entry(n, struct subvol_info, rb_local_node);
- comp = memcmp(entry->uuid, uuid, BTRFS_UUID_SIZE);
- } else if (type == subvol_search_by_root_id) {
- entry = rb_entry(n, struct subvol_info, rb_root_id_node);
- comp = entry->root_id - root_id;
- } else if (type == subvol_search_by_path) {
- entry = rb_entry(n, struct subvol_info, rb_path_node);
- comp = strcmp(entry->path, path);
- } else {
- BUG();
- }
- if (comp < 0)
- n = n->rb_left;
- else if (comp > 0)
- n = n->rb_right;
- else
- return entry;
- }
- return NULL;
-}
-
-static int count_bytes(void *buf, int len, char b)
-{
- int cnt = 0;
- int i;
- for (i = 0; i < len; i++) {
- if (((char*)buf)[i] == b)
- cnt++;
- }
- return cnt;
-}
-
void subvol_uuid_search_add(struct subvol_uuid_search *s,
struct subvol_info *si)
{
- int cnt;
-
- tree_insert(&s->root_id_subvols, si, subvol_search_by_root_id);
- tree_insert(&s->path_subvols, si, subvol_search_by_path);
-
- cnt = count_bytes(si->uuid, BTRFS_UUID_SIZE, 0);
- if (cnt != BTRFS_UUID_SIZE)
- tree_insert(&s->local_subvols, si, subvol_search_by_uuid);
- cnt = count_bytes(si->received_uuid, BTRFS_UUID_SIZE, 0);
- if (cnt != BTRFS_UUID_SIZE)
- tree_insert(&s->received_subvols, si,
- subvol_search_by_received_uuid);
+ if (si) {
+ free(si->path);
+ free(si);
+ }
}
struct subvol_info *subvol_uuid_search(struct subvol_uuid_search *s,
const char *path,
enum subvol_search_type type)
{
- struct rb_root *root;
- if (type == subvol_search_by_received_uuid)
- root = &s->received_subvols;
- else if (type == subvol_search_by_uuid)
- root = &s->local_subvols;
- else if (type == subvol_search_by_root_id)
- root = &s->root_id_subvols;
- else if (type == subvol_search_by_path)
- root = &s->path_subvols;
- else
- return NULL;
- return tree_search(root, root_id, uuid, transid, path, type);
-}
-
-int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
-{
- int ret;
- struct btrfs_ioctl_search_args args;
- struct btrfs_ioctl_search_key *sk = &args.key;
- struct btrfs_ioctl_search_header *sh;
- struct btrfs_root_item *root_item_ptr;
+ int ret = 0;
struct btrfs_root_item root_item;
- struct subvol_info *si = NULL;
- int root_item_valid = 0;
- unsigned long off = 0;
- int i;
- int e;
- char *path;
-
- memset(&args, 0, sizeof(args));
-
- sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
-
- sk->max_objectid = (u64)-1;
- sk->max_offset = (u64)-1;
- sk->max_transid = (u64)-1;
- sk->min_type = BTRFS_ROOT_ITEM_KEY;
- sk->max_type = BTRFS_ROOT_BACKREF_KEY;
- sk->nr_items = 4096;
-
- while(1) {
- ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
- e = errno;
- if (ret < 0) {
- fprintf(stderr, "ERROR: can't perform the search- %s\n",
- strerror(e));
- return ret;
- }
- if (sk->nr_items == 0)
- break;
-
- off = 0;
-
- for (i = 0; i < sk->nr_items; i++) {
- sh = (struct btrfs_ioctl_search_header *)(args.buf +
- off);
- off += sizeof(*sh);
-
- if ((sh->objectid != 5 &&
- sh->objectid < BTRFS_FIRST_FREE_OBJECTID) ||
- sh->objectid > BTRFS_LAST_FREE_OBJECTID)
- goto skip;
-
- if (sh->type == BTRFS_ROOT_ITEM_KEY) {
- /* older kernels don't have uuids+times */
- if (sh->len < sizeof(root_item)) {
- root_item_valid = 0;
- goto skip;
- }
- root_item_ptr = (struct btrfs_root_item *)
- (args.buf + off);
- memcpy(&root_item, root_item_ptr,
- sizeof(root_item));
- root_item_valid = 1;
- } else if (sh->type == BTRFS_ROOT_BACKREF_KEY ||
- root_item_valid) {
- if (!root_item_valid)
- goto skip;
-
- path = btrfs_list_path_for_root(mnt_fd,
- sh->objectid);
- if (!path)
- path = strdup("");
- if (IS_ERR(path)) {
- ret = PTR_ERR(path);
- fprintf(stderr, "ERROR: unable to "
- "resolve path "
- "for root %llu\n",
- sh->objectid);
- goto out;
- }
-
- si = calloc(1, sizeof(*si));
- si->root_id = sh->objectid;
- memcpy(si->uuid, root_item.uuid,
- BTRFS_UUID_SIZE);
- memcpy(si->parent_uuid, root_item.parent_uuid,
- BTRFS_UUID_SIZE);
- memcpy(si->received_uuid,
- root_item.received_uuid,
- BTRFS_UUID_SIZE);
- si->ctransid = btrfs_root_ctransid(&root_item);
- si->otransid = btrfs_root_otransid(&root_item);
- si->stransid = btrfs_root_stransid(&root_item);
- si->rtransid = btrfs_root_rtransid(&root_item);
- si->path = path;
- subvol_uuid_search_add(s, si);
- root_item_valid = 0;
- } else {
- goto skip;
- }
-
-skip:
- off += sh->len;
+ struct subvol_info *info = NULL;
+
+ switch (type) {
+ case subvol_search_by_received_uuid:
+ ret = btrfs_lookup_uuid_received_subvol_item(s->mnt_fd, uuid,
+ &root_id);
+ break;
+ case subvol_search_by_uuid:
+ ret = btrfs_lookup_uuid_subvol_item(s->mnt_fd, uuid, &root_id);
+ break;
+ case subvol_search_by_root_id:
+ break;
+ case subvol_search_by_path:
+ ret = btrfs_get_root_id_by_sub_path(s->mnt_fd, path, &root_id);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
- /*
- * record the mins in sk so we can make sure the
- * next search doesn't repeat this root
- */
- sk->min_objectid = sh->objectid;
- sk->min_offset = sh->offset;
- sk->min_type = sh->type;
- }
- sk->nr_items = 4096;
- if (sk->min_offset < (u64)-1)
- sk->min_offset++;
- else if (sk->min_objectid < (u64)-1) {
- sk->min_objectid++;
- sk->min_offset = 0;
- sk->min_type = 0;
- } else
- break;
+ if (ret)
+ goto out;
+
+ ret = btrfs_read_root_item(s->mnt_fd, root_id, &root_item);
+ if (ret)
+ goto out;
+
+ info = calloc(1, sizeof(*info));
+ info->root_id = root_id;
+ memcpy(info->uuid, root_item.uuid, BTRFS_UUID_SIZE);
+ memcpy(info->received_uuid, root_item.received_uuid, BTRFS_UUID_SIZE);
+ memcpy(info->parent_uuid, root_item.parent_uuid, BTRFS_UUID_SIZE);
+ info->ctransid = btrfs_root_ctransid(&root_item);
+ info->otransid = btrfs_root_otransid(&root_item);
+ info->stransid = btrfs_root_stransid(&root_item);
+ info->rtransid = btrfs_root_rtransid(&root_item);
+ if (type == subvol_search_by_path) {
+ info->path = strdup(path);
+ } else {
+ info->path = malloc(BTRFS_PATH_NAME_MAX);
+ ret = btrfs_subvolid_resolve(s->mnt_fd, info->path,
+ BTRFS_PATH_NAME_MAX, root_id);
}
out:
- return ret;
+ if (ret && info) {
+ free(info->path);
+ free(info);
+ info = NULL;
+ }
+
+ return info;
}
-/*
- * It's safe to call this function even without the subvol_uuid_search_init()
- * call before as long as the subvol_uuid_search structure is all-zero.
- */
-void subvol_uuid_search_finit(struct subvol_uuid_search *s)
+int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
{
- struct rb_root *root = &s->root_id_subvols;
- struct rb_node *node;
-
- while ((node = rb_first(root))) {
- struct subvol_info *entry =
- rb_entry(node, struct subvol_info, rb_root_id_node);
+ s->mnt_fd = mnt_fd;
- free(entry->path);
- rb_erase(node, root);
- free(entry);
- }
+ return 0;
+}
- s->root_id_subvols = RB_ROOT;
- s->local_subvols = RB_ROOT;
- s->received_subvols = RB_ROOT;
- s->path_subvols = RB_ROOT;
+void subvol_uuid_search_finit(struct subvol_uuid_search *s)
+{
}
char *path_cat(const char *p1, const char *p2)
return new;
}
-
char *path_cat3(const char *p1, const char *p2, const char *p3)
{
int p1_len = strlen(p1);
sprintf(new, "%.*s/%.*s/%.*s", p1_len, p1, p2_len, p2, p3_len, p3);
return new;
}
-
projects / platform / upstream / btrfs-progs.git / blobdiff