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![Filipe Manana](/assets/img/avatar_default.png)
btrfs_lookup_dir_index_item() and btrfs_lookup_dir_item() lookup for dir entries and both are used during log replay or when updating a log tree during an unlink. However when the dir item does not exists, btrfs_lookup_dir_item() returns NULL while btrfs_lookup_dir_index_item() returns PTR_ERR(-ENOENT), and if the dir item exists but there is no matching entry for a given name or index, both return NULL. This makes the call sites during log replay to be more verbose than necessary and it makes it easy to miss this slight difference. Since we don't need to distinguish between those two cases, make btrfs_lookup_dir_index_item() always return NULL when there is no matching directory entry - either because there isn't any dir entry or because there is one but it does not match the given name and index. Also rename the argument 'objectid' of btrfs_lookup_dir_index_item() to 'index' since it is supposed to match an index number, and the name 'objectid' is not very good because it can easily be confused with an inode number (like the inode number a dir entry points to). CC: stable@vger.kernel.org # 4.14+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
462 lines
12 KiB
C
462 lines
12 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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/*
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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 btrfs_item *item;
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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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item = btrfs_item_nr(path->slots[0]);
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ptr = btrfs_item_ptr(leaf, path->slots[0], char);
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BUG_ON(data_size > btrfs_item_size(leaf, item));
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ptr += btrfs_item_size(leaf, item) - 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_type(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, const char *name,
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int name_len, 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_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_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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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_type(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_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_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 char *name, int name_len,
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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_len);
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di = btrfs_lookup_match_dir(trans, root, path, &key, name, 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 char *name, int name_len)
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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_len);
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di = btrfs_lookup_match_dir(NULL, root, path, &key, name, 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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/*
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* see if there is room in the item to insert this
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* name
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*/
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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_nr(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 char *name, int name_len,
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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_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,
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struct btrfs_path *path, u64 dirid,
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const char *name, int name_len)
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{
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struct extent_buffer *leaf;
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struct btrfs_dir_item *di;
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struct btrfs_key key;
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u32 nritems;
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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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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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if (ret < 0)
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return ERR_PTR(ret);
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leaf = path->nodes[0];
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nritems = btrfs_header_nritems(leaf);
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while (1) {
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if (path->slots[0] >= nritems) {
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ret = btrfs_next_leaf(root, path);
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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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break;
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leaf = path->nodes[0];
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nritems = btrfs_header_nritems(leaf);
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continue;
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}
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btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
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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_len);
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if (di)
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return di;
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path->slots[0]++;
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}
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return NULL;
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}
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struct btrfs_dir_item *btrfs_lookup_xattr(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 char *name, u16 name_len,
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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_XATTR_ITEM_KEY;
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key.offset = btrfs_name_hash(name, name_len);
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di = btrfs_lookup_match_dir(trans, root, path, &key, name, 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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/*
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* helper function to look at the directory item pointed to by 'path'
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* this walks through all the entries in a dir item and finds one
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* for a specific name.
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*/
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struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path,
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const char *name, int name_len)
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{
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struct btrfs_dir_item *dir_item;
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unsigned long name_ptr;
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u32 total_len;
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u32 cur = 0;
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u32 this_len;
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struct extent_buffer *leaf;
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leaf = path->nodes[0];
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dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
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total_len = btrfs_item_size_nr(leaf, path->slots[0]);
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while (cur < total_len) {
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this_len = sizeof(*dir_item) +
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btrfs_dir_name_len(leaf, dir_item) +
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btrfs_dir_data_len(leaf, dir_item);
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name_ptr = (unsigned long)(dir_item + 1);
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if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
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memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
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return dir_item;
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cur += this_len;
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dir_item = (struct btrfs_dir_item *)((char *)dir_item +
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this_len);
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}
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return NULL;
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}
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/*
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* given a pointer into a directory item, delete it. This
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* handles items that have more than one entry in them.
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*/
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int btrfs_delete_one_dir_name(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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struct btrfs_dir_item *di)
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{
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struct extent_buffer *leaf;
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u32 sub_item_len;
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u32 item_len;
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int ret = 0;
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leaf = path->nodes[0];
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sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
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btrfs_dir_data_len(leaf, di);
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item_len = btrfs_item_size_nr(leaf, path->slots[0]);
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if (sub_item_len == item_len) {
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ret = btrfs_del_item(trans, root, path);
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} else {
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/* MARKER */
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unsigned long ptr = (unsigned long)di;
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unsigned long start;
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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_len - (ptr + sub_item_len - start));
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btrfs_truncate_item(path, item_len - sub_item_len, 1);
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}
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return ret;
|
|
}
|