1 files changed, 192 insertions, 285 deletions

diff --git a/send-utils.c b/send-utils.c
index bacd47ea..874f8a53 100644
--- a/send-utils.c
+++ b/send-utils.c
@@ -16,7 +16,10 @@
  * 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"
@@ -26,6 +29,136 @@
 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)
@@ -122,142 +255,13 @@ static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
 	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,
@@ -265,166 +269,71 @@ 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)
@@ -441,7 +350,6 @@ 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);
@@ -458,4 +366,3 @@ char *path_cat3(const char *p1, const char *p2, const char *p3)
 	sprintf(new, "%.*s/%.*s/%.*s", p1_len, p1, p2_len, p2, p3_len, p3);
 	return new;
 }
-