Inode items hold all of the traditional data returned by stat in
the btree. There is a back reference item stored in the btree for
each directory item that points to an inode.
This has routines to maintain the inode items and their backreferences.
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
new file mode 100644
index 0000000..3d46fa1
--- /dev/null
+++ b/fs/btrfs/inode-item.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+
+static int find_name_in_backref(struct btrfs_path *path, const char *name,
+ int name_len, struct btrfs_inode_ref **ref_ret)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_inode_ref *ref;
+ unsigned long ptr;
+ unsigned long name_ptr;
+ u32 item_size;
+ u32 cur_offset = 0;
+ int len;
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ while (cur_offset < item_size) {
+ ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
+ len = btrfs_inode_ref_name_len(leaf, ref);
+ name_ptr = (unsigned long)(ref + 1);
+ cur_offset += len + sizeof(*ref);
+ if (len != name_len)
+ continue;
+ if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
+ *ref_ret = ref;
+ return 1;
+ }
+ }
+ return 0;
+}
+
+int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid, u64 *index)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_inode_ref *ref;
+ struct extent_buffer *leaf;
+ unsigned long ptr;
+ unsigned long item_start;
+ u32 item_size;
+ u32 sub_item_len;
+ int ret;
+ int del_len = name_len + sizeof(*ref);
+
+ key.objectid = inode_objectid;
+ key.offset = ref_objectid;
+ btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ } else if (ret < 0) {
+ goto out;
+ }
+ if (!find_name_in_backref(path, name, name_len, &ref)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+
+ if (index)
+ *index = btrfs_inode_ref_index(leaf, ref);
+
+ if (del_len == item_size) {
+ ret = btrfs_del_item(trans, root, path);
+ goto out;
+ }
+ ptr = (unsigned long)ref;
+ sub_item_len = name_len + sizeof(*ref);
+ item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
+ item_size - (ptr + sub_item_len - item_start));
+ ret = btrfs_truncate_item(trans, root, path,
+ item_size - sub_item_len, 1);
+ BUG_ON(ret);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid, u64 index)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_inode_ref *ref;
+ unsigned long ptr;
+ int ret;
+ int ins_len = name_len + sizeof(*ref);
+
+ key.objectid = inode_objectid;
+ key.offset = ref_objectid;
+ btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_insert_empty_item(trans, root, path, &key,
+ ins_len);
+ if (ret == -EEXIST) {
+ u32 old_size;
+
+ if (find_name_in_backref(path, name, name_len, &ref))
+ goto out;
+
+ old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
+ ret = btrfs_extend_item(trans, root, path, ins_len);
+ BUG_ON(ret);
+ ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_inode_ref);
+ ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
+ btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
+ btrfs_set_inode_ref_index(path->nodes[0], ref, index);
+ ptr = (unsigned long)(ref + 1);
+ ret = 0;
+ } else if (ret < 0) {
+ goto out;
+ } else {
+ ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_inode_ref);
+ btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
+ btrfs_set_inode_ref_index(path->nodes[0], ref, index);
+ ptr = (unsigned long)(ref + 1);
+ }
+ write_extent_buffer(path->nodes[0], name, ptr, name_len);
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 objectid)
+{
+ struct btrfs_key key;
+ int ret;
+ key.objectid = objectid;
+ btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+ key.offset = 0;
+
+ ret = btrfs_insert_empty_item(trans, root, path, &key,
+ sizeof(struct btrfs_inode_item));
+ if (ret == 0 && objectid > root->highest_inode)
+ root->highest_inode = objectid;
+ return ret;
+}
+
+int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_path *path,
+ struct btrfs_key *location, int mod)
+{
+ int ins_len = mod < 0 ? -1 : 0;
+ int cow = mod != 0;
+ int ret;
+ int slot;
+ struct extent_buffer *leaf;
+ struct btrfs_key found_key;
+
+ ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
+ if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
+ location->offset == (u64)-1 && path->slots[0] != 0) {
+ slot = path->slots[0] - 1;
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+ if (found_key.objectid == location->objectid &&
+ btrfs_key_type(&found_key) == btrfs_key_type(location)) {
+ path->slots[0]--;
+ return 0;
+ }
+ }
+ return ret;
+}
--
1.6.0.2
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