428 lines
11 KiB
C
428 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "print-tree.h"
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struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
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int slot, const char *name,
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int name_len)
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{
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struct btrfs_inode_ref *ref;
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unsigned long ptr;
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unsigned long name_ptr;
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u32 item_size;
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u32 cur_offset = 0;
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int len;
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item_size = btrfs_item_size_nr(leaf, slot);
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ptr = btrfs_item_ptr_offset(leaf, slot);
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while (cur_offset < item_size) {
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ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
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len = btrfs_inode_ref_name_len(leaf, ref);
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name_ptr = (unsigned long)(ref + 1);
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cur_offset += len + sizeof(*ref);
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if (len != name_len)
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continue;
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if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
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return ref;
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}
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return NULL;
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}
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struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
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struct extent_buffer *leaf, int slot, u64 ref_objectid,
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const char *name, int name_len)
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{
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struct btrfs_inode_extref *extref;
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unsigned long ptr;
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unsigned long name_ptr;
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u32 item_size;
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u32 cur_offset = 0;
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int ref_name_len;
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item_size = btrfs_item_size_nr(leaf, slot);
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ptr = btrfs_item_ptr_offset(leaf, slot);
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/*
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* Search all extended backrefs in this item. We're only
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* looking through any collisions so most of the time this is
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* just going to compare against one buffer. If all is well,
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* we'll return success and the inode ref object.
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*/
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while (cur_offset < item_size) {
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extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
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name_ptr = (unsigned long)(&extref->name);
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ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
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if (ref_name_len == name_len &&
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btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
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(memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0))
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return extref;
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cur_offset += ref_name_len + sizeof(*extref);
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}
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return NULL;
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}
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/* Returns NULL if no extref found */
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struct btrfs_inode_extref *
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btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, int ins_len,
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int cow)
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{
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int ret;
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struct btrfs_key key;
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key.objectid = inode_objectid;
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key.type = BTRFS_INODE_EXTREF_KEY;
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key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
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ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
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if (ret < 0)
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return ERR_PTR(ret);
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if (ret > 0)
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return NULL;
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return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
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ref_objectid, name, name_len);
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}
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static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid,
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u64 *index)
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{
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_inode_extref *extref;
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struct extent_buffer *leaf;
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int ret;
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int del_len = name_len + sizeof(*extref);
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unsigned long ptr;
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unsigned long item_start;
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u32 item_size;
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key.objectid = inode_objectid;
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key.type = BTRFS_INODE_EXTREF_KEY;
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key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
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if (ret > 0)
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ret = -ENOENT;
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if (ret < 0)
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goto out;
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/*
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* Sanity check - did we find the right item for this name?
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* This should always succeed so error here will make the FS
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* readonly.
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*/
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extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
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ref_objectid, name, name_len);
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if (!extref) {
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btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
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ret = -EROFS;
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goto out;
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}
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leaf = path->nodes[0];
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item_size = btrfs_item_size_nr(leaf, path->slots[0]);
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if (index)
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*index = btrfs_inode_extref_index(leaf, extref);
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if (del_len == item_size) {
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/*
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* Common case only one ref in the item, remove the
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* whole item.
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*/
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ret = btrfs_del_item(trans, root, path);
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goto out;
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}
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ptr = (unsigned long)extref;
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item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
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memmove_extent_buffer(leaf, ptr, ptr + del_len,
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item_size - (ptr + del_len - item_start));
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btrfs_truncate_item(path, item_size - del_len, 1);
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out:
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, u64 *index)
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{
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_inode_ref *ref;
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struct extent_buffer *leaf;
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unsigned long ptr;
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unsigned long item_start;
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u32 item_size;
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u32 sub_item_len;
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int ret;
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int search_ext_refs = 0;
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int del_len = name_len + sizeof(*ref);
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key.objectid = inode_objectid;
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key.offset = ref_objectid;
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key.type = BTRFS_INODE_REF_KEY;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
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if (ret > 0) {
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ret = -ENOENT;
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search_ext_refs = 1;
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goto out;
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} else if (ret < 0) {
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goto out;
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}
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ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name,
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name_len);
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if (!ref) {
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ret = -ENOENT;
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search_ext_refs = 1;
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goto out;
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}
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leaf = path->nodes[0];
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item_size = btrfs_item_size_nr(leaf, path->slots[0]);
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if (index)
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*index = btrfs_inode_ref_index(leaf, ref);
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if (del_len == item_size) {
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ret = btrfs_del_item(trans, root, path);
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goto out;
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}
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ptr = (unsigned long)ref;
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sub_item_len = name_len + sizeof(*ref);
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item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
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memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
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item_size - (ptr + sub_item_len - item_start));
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btrfs_truncate_item(path, item_size - sub_item_len, 1);
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out:
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btrfs_free_path(path);
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if (search_ext_refs) {
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/*
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* No refs were found, or we could not find the
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* name in our ref array. Find and remove the extended
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* inode ref then.
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*/
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return btrfs_del_inode_extref(trans, root, name, name_len,
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inode_objectid, ref_objectid, index);
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}
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return ret;
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}
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/*
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* btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
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*
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* The caller must have checked against BTRFS_LINK_MAX already.
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*/
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static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, u64 index)
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{
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struct btrfs_inode_extref *extref;
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int ret;
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int ins_len = name_len + sizeof(*extref);
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unsigned long ptr;
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struct btrfs_path *path;
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struct btrfs_key key;
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struct extent_buffer *leaf;
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struct btrfs_item *item;
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key.objectid = inode_objectid;
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key.type = BTRFS_INODE_EXTREF_KEY;
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key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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ret = btrfs_insert_empty_item(trans, root, path, &key,
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ins_len);
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if (ret == -EEXIST) {
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if (btrfs_find_name_in_ext_backref(path->nodes[0],
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path->slots[0],
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ref_objectid,
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name, name_len))
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goto out;
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btrfs_extend_item(path, ins_len);
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ret = 0;
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}
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if (ret < 0)
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goto out;
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leaf = path->nodes[0];
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item = btrfs_item_nr(path->slots[0]);
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ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
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ptr += btrfs_item_size(leaf, item) - ins_len;
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extref = (struct btrfs_inode_extref *)ptr;
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btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
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btrfs_set_inode_extref_index(path->nodes[0], extref, index);
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btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
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ptr = (unsigned long)&extref->name;
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write_extent_buffer(path->nodes[0], name, ptr, name_len);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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out:
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btrfs_free_path(path);
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return ret;
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}
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/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
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int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, u64 index)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_inode_ref *ref;
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unsigned long ptr;
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int ret;
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int ins_len = name_len + sizeof(*ref);
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key.objectid = inode_objectid;
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key.offset = ref_objectid;
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key.type = BTRFS_INODE_REF_KEY;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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path->skip_release_on_error = 1;
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ret = btrfs_insert_empty_item(trans, root, path, &key,
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ins_len);
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if (ret == -EEXIST) {
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u32 old_size;
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ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
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name, name_len);
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if (ref)
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goto out;
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old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
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btrfs_extend_item(path, ins_len);
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ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_inode_ref);
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ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
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btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
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btrfs_set_inode_ref_index(path->nodes[0], ref, index);
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ptr = (unsigned long)(ref + 1);
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ret = 0;
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} else if (ret < 0) {
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if (ret == -EOVERFLOW) {
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if (btrfs_find_name_in_backref(path->nodes[0],
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path->slots[0],
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name, name_len))
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ret = -EEXIST;
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else
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ret = -EMLINK;
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}
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goto out;
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} else {
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ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_inode_ref);
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btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
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btrfs_set_inode_ref_index(path->nodes[0], ref, index);
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ptr = (unsigned long)(ref + 1);
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}
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write_extent_buffer(path->nodes[0], name, ptr, name_len);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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out:
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btrfs_free_path(path);
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if (ret == -EMLINK) {
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struct btrfs_super_block *disk_super = fs_info->super_copy;
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/* We ran out of space in the ref array. Need to
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* add an extended ref. */
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if (btrfs_super_incompat_flags(disk_super)
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& BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
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ret = btrfs_insert_inode_extref(trans, root, name,
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name_len,
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inode_objectid,
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ref_objectid, index);
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}
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return ret;
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}
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int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 objectid)
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{
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struct btrfs_key key;
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int ret;
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key.objectid = objectid;
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key.type = BTRFS_INODE_ITEM_KEY;
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key.offset = 0;
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ret = btrfs_insert_empty_item(trans, root, path, &key,
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sizeof(struct btrfs_inode_item));
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return ret;
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}
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int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_path *path,
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struct btrfs_key *location, int mod)
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{
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int ins_len = mod < 0 ? -1 : 0;
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int cow = mod != 0;
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int ret;
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int slot;
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struct extent_buffer *leaf;
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struct btrfs_key found_key;
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ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
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if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
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location->offset == (u64)-1 && path->slots[0] != 0) {
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slot = path->slots[0] - 1;
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leaf = path->nodes[0];
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btrfs_item_key_to_cpu(leaf, &found_key, slot);
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if (found_key.objectid == location->objectid &&
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found_key.type == location->type) {
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path->slots[0]--;
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return 0;
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}
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}
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return ret;
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}
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