X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fbtrfs%2Froot-tree.c;h=0ddc6d61c55a7135bd94c15c76644011c6e9fd4c;hb=cd5232bd6be2d215a800f3d88c287ca791debfbe;hp=3b5926dfbeba628f8508e095878ccac565f9f509;hpb=5ce14bbcdd1b5d9233d26a1e89faf3a26c820c58;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 3b5926d..0ddc6d6 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -21,17 +21,70 @@
 #include "disk-io.h"
 #include "print-tree.h"
 
+/*
+ *  search forward for a root, starting with objectid 'search_start'
+ *  if a root key is found, the objectid we find is filled into 'found_objectid'
+ *  and 0 is returned.  < 0 is returned on error, 1 if there is nothing
+ *  left in the tree.
+ */
+int btrfs_search_root(struct btrfs_root *root, u64 search_start,
+		      u64 *found_objectid)
+{
+	struct btrfs_path *path;
+	struct btrfs_key search_key;
+	int ret;
+
+	root = root->fs_info->tree_root;
+	search_key.objectid = search_start;
+	search_key.type = (u8)-1;
+	search_key.offset = (u64)-1;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+again:
+	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	if (ret == 0) {
+		ret = 1;
+		goto out;
+	}
+	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+		ret = btrfs_next_leaf(root, path);
+		if (ret)
+			goto out;
+	}
+	btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
+	if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
+		search_key.offset++;
+		btrfs_release_path(root, path);
+		goto again;
+	}
+	ret = 0;
+	*found_objectid = search_key.objectid;
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * lookup the root with the highest offset for a given objectid.  The key we do
+ * find is copied into 'key'.  If we find something return 0, otherwise 1, < 0
+ * on error.
+ */
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 			struct btrfs_root_item *item, struct btrfs_key *key)
 {
 	struct btrfs_path *path;
 	struct btrfs_key search_key;
-	struct btrfs_leaf *l;
+	struct btrfs_key found_key;
+	struct extent_buffer *l;
 	int ret;
 	int slot;
 
 	search_key.objectid = objectid;
-	search_key.flags = (u32)-1;
+	search_key.type = BTRFS_ROOT_ITEM_KEY;
 	search_key.offset = (u64)-1;
 
 	path = btrfs_alloc_path();
@@ -39,44 +92,65 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
 	if (ret < 0)
 		goto out;
+
 	BUG_ON(ret == 0);
-	l = btrfs_buffer_leaf(path->nodes[0]);
+	l = path->nodes[0];
 	BUG_ON(path->slots[0] == 0);
 	slot = path->slots[0] - 1;
-	if (btrfs_disk_key_objectid(&l->items[slot].key) != objectid) {
+	btrfs_item_key_to_cpu(l, &found_key, slot);
+	if (found_key.objectid != objectid) {
 		ret = 1;
 		goto out;
 	}
-	memcpy(item, btrfs_item_ptr(l, slot, struct btrfs_root_item),
-		sizeof(*item));
-	btrfs_disk_key_to_cpu(key, &l->items[slot].key);
+	read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
+			   sizeof(*item));
+	memcpy(key, &found_key, sizeof(found_key));
 	ret = 0;
 out:
-	btrfs_release_path(root, path);
 	btrfs_free_path(path);
 	return ret;
 }
 
+int btrfs_set_root_node(struct btrfs_root_item *item,
+			struct extent_buffer *node)
+{
+	btrfs_set_root_bytenr(item, node->start);
+	btrfs_set_root_level(item, btrfs_header_level(node));
+	btrfs_set_root_generation(item, btrfs_header_generation(node));
+	return 0;
+}
+
+/*
+ * copy the data in 'item' into the btree
+ */
 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 		      *root, struct btrfs_key *key, struct btrfs_root_item
 		      *item)
 {
 	struct btrfs_path *path;
-	struct btrfs_leaf *l;
+	struct extent_buffer *l;
 	int ret;
 	int slot;
-	struct btrfs_root_item *update_item;
+	unsigned long ptr;
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
 	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
 	if (ret < 0)
 		goto out;
-	BUG_ON(ret != 0);
-	l = btrfs_buffer_leaf(path->nodes[0]);
+
+	if (ret != 0) {
+		btrfs_print_leaf(root, path->nodes[0]);
+		printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
+		       (unsigned long long)key->objectid, key->type,
+		       (unsigned long long)key->offset);
+		BUG_ON(1);
+	}
+
+	l = path->nodes[0];
 	slot = path->slots[0];
-	update_item = btrfs_item_ptr(l, slot, struct btrfs_root_item);
-	btrfs_memcpy(root, l, update_item, item, sizeof(*item));
+	ptr = btrfs_item_ptr_offset(l, slot);
+	write_extent_buffer(l, item, ptr, sizeof(*item));
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
 	btrfs_release_path(root, path);
@@ -93,43 +167,50 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	return ret;
 }
 
-int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
-			  struct btrfs_root *latest)
+/*
+ * at mount time we want to find all the old transaction snapshots that were in
+ * the process of being deleted if we crashed.  This is any root item with an
+ * offset lower than the latest root.  They need to be queued for deletion to
+ * finish what was happening when we crashed.
+ */
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
 {
 	struct btrfs_root *dead_root;
 	struct btrfs_item *item;
 	struct btrfs_root_item *ri;
 	struct btrfs_key key;
+	struct btrfs_key found_key;
 	struct btrfs_path *path;
 	int ret;
 	u32 nritems;
-	struct btrfs_leaf *leaf;
+	struct extent_buffer *leaf;
 	int slot;
 
 	key.objectid = objectid;
-	key.flags = 0;
 	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 	key.offset = 0;
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
+
+again:
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto err;
-	while(1) {
-		leaf = btrfs_buffer_leaf(path->nodes[0]);
-		nritems = btrfs_header_nritems(&leaf->header);
+	while (1) {
+		leaf = path->nodes[0];
+		nritems = btrfs_header_nritems(leaf);
 		slot = path->slots[0];
 		if (slot >= nritems) {
 			ret = btrfs_next_leaf(root, path);
 			if (ret)
 				break;
-			leaf = btrfs_buffer_leaf(path->nodes[0]);
-			nritems = btrfs_header_nritems(&leaf->header);
+			leaf = path->nodes[0];
+			nritems = btrfs_header_nritems(leaf);
 			slot = path->slots[0];
 		}
-		item = leaf->items + slot;
-		btrfs_disk_key_to_cpu(&key, &item->key);
+		item = btrfs_item_nr(leaf, slot);
+		btrfs_item_key_to_cpu(leaf, &key, slot);
 		if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
 			goto next;
 
@@ -140,19 +221,24 @@ int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
 			break;
 
 		ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
-		if (btrfs_root_refs(ri) != 0)
+		if (btrfs_disk_root_refs(leaf, ri) != 0)
 			goto next;
 
-		dead_root = btrfs_read_fs_root_no_radix(root->fs_info, &key);
+		memcpy(&found_key, &key, sizeof(key));
+		key.offset++;
+		btrfs_release_path(root, path);
+		dead_root =
+			btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+						    &found_key);
 		if (IS_ERR(dead_root)) {
 			ret = PTR_ERR(dead_root);
 			goto err;
 		}
 
-		ret = btrfs_add_dead_root(dead_root, latest,
-					  &root->fs_info->dead_roots);
+		ret = btrfs_add_dead_root(dead_root);
 		if (ret)
 			goto err;
+		goto again;
 next:
 		slot++;
 		path->slots[0]++;
@@ -163,6 +249,7 @@ err:
 	return ret;
 }
 
+/* drop the root item for 'key' from 'root' */
 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		   struct btrfs_key *key)
 {
@@ -170,17 +257,19 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	int ret;
 	u32 refs;
 	struct btrfs_root_item *ri;
+	struct extent_buffer *leaf;
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
 	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
 	if (ret < 0)
 		goto out;
+
 	BUG_ON(ret != 0);
-	ri = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
-			    path->slots[0], struct btrfs_root_item);
+	leaf = path->nodes[0];
+	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
 
-	refs = btrfs_root_refs(ri);
+	refs = btrfs_disk_root_refs(leaf, ri);
 	BUG_ON(refs != 0);
 	ret = btrfs_del_item(trans, root, path);
 out:
@@ -188,3 +277,95 @@ out:
 	btrfs_free_path(path);
 	return ret;
 }
+
+#if 0 /* this will get used when snapshot deletion is implemented */
+int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *tree_root,
+		       u64 root_id, u8 type, u64 ref_id)
+{
+	struct btrfs_key key;
+	int ret;
+	struct btrfs_path *path;
+
+	path = btrfs_alloc_path();
+
+	key.objectid = root_id;
+	key.type = type;
+	key.offset = ref_id;
+
+	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
+	BUG_ON(ret);
+
+	ret = btrfs_del_item(trans, tree_root, path);
+	BUG_ON(ret);
+
+	btrfs_free_path(path);
+	return ret;
+}
+#endif
+
+int btrfs_find_root_ref(struct btrfs_root *tree_root,
+		   struct btrfs_path *path,
+		   u64 root_id, u64 ref_id)
+{
+	struct btrfs_key key;
+	int ret;
+
+	key.objectid = root_id;
+	key.type = BTRFS_ROOT_REF_KEY;
+	key.offset = ref_id;
+
+	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+	return ret;
+}
+
+
+/*
+ * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
+ * or BTRFS_ROOT_BACKREF_KEY.
+ *
+ * The dirid, sequence, name and name_len refer to the directory entry
+ * that is referencing the root.
+ *
+ * For a forward ref, the root_id is the id of the tree referencing
+ * the root and ref_id is the id of the subvol  or snapshot.
+ *
+ * For a back ref the root_id is the id of the subvol or snapshot and
+ * ref_id is the id of the tree referencing it.
+ */
+int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *tree_root,
+		       u64 root_id, u8 type, u64 ref_id,
+		       u64 dirid, u64 sequence,
+		       const char *name, int name_len)
+{
+	struct btrfs_key key;
+	int ret;
+	struct btrfs_path *path;
+	struct btrfs_root_ref *ref;
+	struct extent_buffer *leaf;
+	unsigned long ptr;
+
+
+	path = btrfs_alloc_path();
+
+	key.objectid = root_id;
+	key.type = type;
+	key.offset = ref_id;
+
+	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
+				      sizeof(*ref) + name_len);
+	BUG_ON(ret);
+
+	leaf = path->nodes[0];
+	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+	btrfs_set_root_ref_dirid(leaf, ref, dirid);
+	btrfs_set_root_ref_sequence(leaf, ref, sequence);
+	btrfs_set_root_ref_name_len(leaf, ref, name_len);
+	ptr = (unsigned long)(ref + 1);
+	write_extent_buffer(leaf, name, ptr, name_len);
+	btrfs_mark_buffer_dirty(leaf);
+
+	btrfs_free_path(path);
+	return ret;
+}