From 3954401fa6013bb2f2c8758b903e9bffcf25b64b Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 12 Dec 2007 14:38:19 -0500 Subject: Btrfs: Add back pointers from the inode to the directory that references it Signed-off-by: Chris Mason --- fs/btrfs/inode-item.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) (limited to 'fs/btrfs/inode-item.c') diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c index 35d2608f891..cba30b6cc6f 100644 --- a/fs/btrfs/inode-item.c +++ b/fs/btrfs/inode-item.c @@ -20,6 +20,142 @@ #include "disk-io.h" #include "transaction.h" +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) +{ + 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 (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) +{ + 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); + 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); + 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) -- cgit v1.2.3