446 lines
12 KiB
C
446 lines
12 KiB
C
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// 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 "messages.h"
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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 "accessors.h"
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#include "dir-item.h"
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/*
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* insert a name into a directory, doing overflow properly if there is a hash
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* collision. data_size indicates how big the item inserted should be. On
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* success a struct btrfs_dir_item pointer is returned, otherwise it is
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* an ERR_PTR.
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*
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* The name is not copied into the dir item, you have to do that yourself.
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*/
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static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
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*trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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struct btrfs_key *cpu_key,
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u32 data_size,
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const char *name,
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int name_len)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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int ret;
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char *ptr;
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struct extent_buffer *leaf;
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ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
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if (ret == -EEXIST) {
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struct btrfs_dir_item *di;
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di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
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if (di)
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return ERR_PTR(-EEXIST);
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btrfs_extend_item(path, data_size);
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} else if (ret < 0)
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return ERR_PTR(ret);
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WARN_ON(ret > 0);
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leaf = path->nodes[0];
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ptr = btrfs_item_ptr(leaf, path->slots[0], char);
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ASSERT(data_size <= btrfs_item_size(leaf, path->slots[0]));
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ptr += btrfs_item_size(leaf, path->slots[0]) - data_size;
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return (struct btrfs_dir_item *)ptr;
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}
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/*
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* xattrs work a lot like directories, this inserts an xattr item
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* into the tree
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*/
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int btrfs_insert_xattr_item(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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const char *name, u16 name_len,
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const void *data, u16 data_len)
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{
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int ret = 0;
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struct btrfs_dir_item *dir_item;
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unsigned long name_ptr, data_ptr;
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struct btrfs_key key, location;
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struct btrfs_disk_key disk_key;
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struct extent_buffer *leaf;
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u32 data_size;
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if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
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return -ENOSPC;
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key.objectid = objectid;
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key.type = BTRFS_XATTR_ITEM_KEY;
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key.offset = btrfs_name_hash(name, name_len);
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data_size = sizeof(*dir_item) + name_len + data_len;
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dir_item = insert_with_overflow(trans, root, path, &key, data_size,
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name, name_len);
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if (IS_ERR(dir_item))
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return PTR_ERR(dir_item);
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memset(&location, 0, sizeof(location));
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leaf = path->nodes[0];
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btrfs_cpu_key_to_disk(&disk_key, &location);
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btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
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btrfs_set_dir_flags(leaf, dir_item, BTRFS_FT_XATTR);
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btrfs_set_dir_name_len(leaf, dir_item, name_len);
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btrfs_set_dir_transid(leaf, dir_item, trans->transid);
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btrfs_set_dir_data_len(leaf, dir_item, data_len);
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name_ptr = (unsigned long)(dir_item + 1);
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data_ptr = (unsigned long)((char *)name_ptr + name_len);
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write_extent_buffer(leaf, name, name_ptr, name_len);
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write_extent_buffer(leaf, data, data_ptr, data_len);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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return ret;
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}
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/*
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* insert a directory item in the tree, doing all the magic for
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* both indexes. 'dir' indicates which objectid to insert it into,
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* 'location' is the key to stuff into the directory item, 'type' is the
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* type of the inode we're pointing to, and 'index' is the sequence number
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* to use for the second index (if one is created).
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* Will return 0 or -ENOMEM
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*/
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int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
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const struct fscrypt_str *name, struct btrfs_inode *dir,
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struct btrfs_key *location, u8 type, u64 index)
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{
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int ret = 0;
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int ret2 = 0;
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struct btrfs_root *root = dir->root;
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struct btrfs_path *path;
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struct btrfs_dir_item *dir_item;
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struct extent_buffer *leaf;
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unsigned long name_ptr;
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struct btrfs_key key;
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struct btrfs_disk_key disk_key;
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u32 data_size;
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key.objectid = btrfs_ino(dir);
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key.type = BTRFS_DIR_ITEM_KEY;
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key.offset = btrfs_name_hash(name->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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btrfs_cpu_key_to_disk(&disk_key, location);
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data_size = sizeof(*dir_item) + name->len;
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dir_item = insert_with_overflow(trans, root, path, &key, data_size,
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name->name, name->len);
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if (IS_ERR(dir_item)) {
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ret = PTR_ERR(dir_item);
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if (ret == -EEXIST)
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goto second_insert;
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goto out_free;
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}
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if (IS_ENCRYPTED(&dir->vfs_inode))
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type |= BTRFS_FT_ENCRYPTED;
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leaf = path->nodes[0];
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btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
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btrfs_set_dir_flags(leaf, dir_item, type);
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btrfs_set_dir_data_len(leaf, dir_item, 0);
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btrfs_set_dir_name_len(leaf, dir_item, name->len);
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btrfs_set_dir_transid(leaf, dir_item, trans->transid);
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name_ptr = (unsigned long)(dir_item + 1);
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write_extent_buffer(leaf, name->name, name_ptr, name->len);
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btrfs_mark_buffer_dirty(leaf);
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second_insert:
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/* FIXME, use some real flag for selecting the extra index */
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if (root == root->fs_info->tree_root) {
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ret = 0;
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goto out_free;
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}
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btrfs_release_path(path);
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ret2 = btrfs_insert_delayed_dir_index(trans, name->name, name->len, dir,
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&disk_key, type, index);
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out_free:
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btrfs_free_path(path);
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if (ret)
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return ret;
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if (ret2)
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return ret2;
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return 0;
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}
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static struct btrfs_dir_item *btrfs_lookup_match_dir(
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struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct btrfs_path *path,
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struct btrfs_key *key, const char *name,
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int name_len, int mod)
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{
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const int ins_len = (mod < 0 ? -1 : 0);
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const int cow = (mod != 0);
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int ret;
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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 ERR_PTR(-ENOENT);
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return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
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}
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/*
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* Lookup for a directory item by name.
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*
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* @trans: The transaction handle to use. Can be NULL if @mod is 0.
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* @root: The root of the target tree.
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* @path: Path to use for the search.
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* @dir: The inode number (objectid) of the directory.
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* @name: The name associated to the directory entry we are looking for.
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* @name_len: The length of the name.
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* @mod: Used to indicate if the tree search is meant for a read only
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* lookup, for a modification lookup or for a deletion lookup, so
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* its value should be 0, 1 or -1, respectively.
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*
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* Returns: NULL if the dir item does not exists, an error pointer if an error
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* happened, or a pointer to a dir item if a dir item exists for the given name.
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*/
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struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 dir,
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const struct fscrypt_str *name,
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int mod)
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{
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struct btrfs_key key;
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struct btrfs_dir_item *di;
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key.objectid = dir;
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key.type = BTRFS_DIR_ITEM_KEY;
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key.offset = btrfs_name_hash(name->name, name->len);
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di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
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name->len, mod);
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if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
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return NULL;
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return di;
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}
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int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
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const struct fscrypt_str *name)
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{
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int ret;
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struct btrfs_key key;
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struct btrfs_dir_item *di;
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int data_size;
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struct extent_buffer *leaf;
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int slot;
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struct btrfs_path *path;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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key.objectid = dir;
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key.type = BTRFS_DIR_ITEM_KEY;
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key.offset = btrfs_name_hash(name->name, name->len);
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di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
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name->len, 0);
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if (IS_ERR(di)) {
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ret = PTR_ERR(di);
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/* Nothing found, we're safe */
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if (ret == -ENOENT) {
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ret = 0;
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goto out;
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}
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if (ret < 0)
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goto out;
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}
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/* we found an item, look for our name in the item */
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if (di) {
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/* our exact name was found */
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ret = -EEXIST;
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goto out;
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}
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/* See if there is room in the item to insert this name. */
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data_size = sizeof(*di) + name->len;
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leaf = path->nodes[0];
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slot = path->slots[0];
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if (data_size + btrfs_item_size(leaf, slot) +
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sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
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ret = -EOVERFLOW;
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} else {
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/* plenty of insertion room */
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ret = 0;
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}
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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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/*
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* Lookup for a directory index item by name and index number.
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*
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* @trans: The transaction handle to use. Can be NULL if @mod is 0.
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* @root: The root of the target tree.
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* @path: Path to use for the search.
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* @dir: The inode number (objectid) of the directory.
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* @index: The index number.
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* @name: The name associated to the directory entry we are looking for.
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* @name_len: The length of the name.
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* @mod: Used to indicate if the tree search is meant for a read only
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* lookup, for a modification lookup or for a deletion lookup, so
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* its value should be 0, 1 or -1, respectively.
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*
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* Returns: NULL if the dir index item does not exists, an error pointer if an
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* error happened, or a pointer to a dir item if the dir index item exists and
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* matches the criteria (name and index number).
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*/
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struct btrfs_dir_item *
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btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 dir,
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u64 index, const struct fscrypt_str *name, int mod)
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{
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struct btrfs_dir_item *di;
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struct btrfs_key key;
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key.objectid = dir;
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key.type = BTRFS_DIR_INDEX_KEY;
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key.offset = index;
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di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
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name->len, mod);
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if (di == ERR_PTR(-ENOENT))
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return NULL;
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return di;
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}
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struct btrfs_dir_item *
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btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
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u64 dirid, const struct fscrypt_str *name)
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{
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struct btrfs_dir_item *di;
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struct btrfs_key key;
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int ret;
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key.objectid = dirid;
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key.type = BTRFS_DIR_INDEX_KEY;
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key.offset = 0;
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btrfs_for_each_slot(root, &key, &key, path, ret) {
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if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
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break;
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di = btrfs_match_dir_item_name(root->fs_info, path,
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name->name, name->len);
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if (di)
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return di;
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}
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/* Adjust return code if the key was not found in the next leaf. */
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if (ret > 0)
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ret = 0;
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return ERR_PTR(ret);
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}
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struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
|
||
|
|
struct btrfs_root *root,
|
||
|
|
struct btrfs_path *path, u64 dir,
|
||
|
|
const char *name, u16 name_len,
|
||
|
|
int mod)
|
||
|
|
{
|
||
|
|
struct btrfs_key key;
|
||
|
|
struct btrfs_dir_item *di;
|
||
|
|
|
||
|
|
key.objectid = dir;
|
||
|
|
key.type = BTRFS_XATTR_ITEM_KEY;
|
||
|
|
key.offset = btrfs_name_hash(name, name_len);
|
||
|
|
|
||
|
|
di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
|
||
|
|
if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
|
||
|
|
return NULL;
|
||
|
|
|
||
|
|
return di;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* helper function to look at the directory item pointed to by 'path'
|
||
|
|
* this walks through all the entries in a dir item and finds one
|
||
|
|
* for a specific name.
|
||
|
|
*/
|
||
|
|
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
|
||
|
|
struct btrfs_path *path,
|
||
|
|
const char *name, int name_len)
|
||
|
|
{
|
||
|
|
struct btrfs_dir_item *dir_item;
|
||
|
|
unsigned long name_ptr;
|
||
|
|
u32 total_len;
|
||
|
|
u32 cur = 0;
|
||
|
|
u32 this_len;
|
||
|
|
struct extent_buffer *leaf;
|
||
|
|
|
||
|
|
leaf = path->nodes[0];
|
||
|
|
dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
|
||
|
|
|
||
|
|
total_len = btrfs_item_size(leaf, path->slots[0]);
|
||
|
|
while (cur < total_len) {
|
||
|
|
this_len = sizeof(*dir_item) +
|
||
|
|
btrfs_dir_name_len(leaf, dir_item) +
|
||
|
|
btrfs_dir_data_len(leaf, dir_item);
|
||
|
|
name_ptr = (unsigned long)(dir_item + 1);
|
||
|
|
|
||
|
|
if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
|
||
|
|
memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
|
||
|
|
return dir_item;
|
||
|
|
|
||
|
|
cur += this_len;
|
||
|
|
dir_item = (struct btrfs_dir_item *)((char *)dir_item +
|
||
|
|
this_len);
|
||
|
|
}
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* given a pointer into a directory item, delete it. This
|
||
|
|
* handles items that have more than one entry in them.
|
||
|
|
*/
|
||
|
|
int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
|
||
|
|
struct btrfs_root *root,
|
||
|
|
struct btrfs_path *path,
|
||
|
|
struct btrfs_dir_item *di)
|
||
|
|
{
|
||
|
|
|
||
|
|
struct extent_buffer *leaf;
|
||
|
|
u32 sub_item_len;
|
||
|
|
u32 item_len;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
leaf = path->nodes[0];
|
||
|
|
sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
|
||
|
|
btrfs_dir_data_len(leaf, di);
|
||
|
|
item_len = btrfs_item_size(leaf, path->slots[0]);
|
||
|
|
if (sub_item_len == item_len) {
|
||
|
|
ret = btrfs_del_item(trans, root, path);
|
||
|
|
} else {
|
||
|
|
/* MARKER */
|
||
|
|
unsigned long ptr = (unsigned long)di;
|
||
|
|
unsigned long start;
|
||
|
|
|
||
|
|
start = btrfs_item_ptr_offset(leaf, path->slots[0]);
|
||
|
|
memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
|
||
|
|
item_len - (ptr + sub_item_len - start));
|
||
|
|
btrfs_truncate_item(path, item_len - sub_item_len, 1);
|
||
|
|
}
|
||
|
|
return ret;
|
||
|
|
}
|