linux/fs/btrfs/dir-item.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#include "messages.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "accessors.h"
#include "dir-item.h"

/*
 * insert a name into a directory, doing overflow properly if there is a hash
 * collision.  data_size indicates how big the item inserted should be.  On
 * success a struct btrfs_dir_item pointer is returned, otherwise it is
 * an ERR_PTR.
 *
 * The name is not copied into the dir item, you have to do that yourself.
 */
static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
						   *trans,
						   struct btrfs_root *root,
						   struct btrfs_path *path,
						   const struct btrfs_key *cpu_key,
						   u32 data_size,
						   const char *name,
						   int name_len)
{ … }

/*
 * xattrs work a lot like directories, this inserts an xattr item
 * into the tree
 */
int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root,
			    struct btrfs_path *path, u64 objectid,
			    const char *name, u16 name_len,
			    const void *data, u16 data_len)
{ … }

/*
 * insert a directory item in the tree, doing all the magic for
 * both indexes. 'dir' indicates which objectid to insert it into,
 * 'location' is the key to stuff into the directory item, 'type' is the
 * type of the inode we're pointing to, and 'index' is the sequence number
 * to use for the second index (if one is created).
 * Will return 0 or -ENOMEM
 */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
			  const struct fscrypt_str *name, struct btrfs_inode *dir,
			  const struct btrfs_key *location, u8 type, u64 index)
{ … }

static struct btrfs_dir_item *btrfs_lookup_match_dir(
			struct btrfs_trans_handle *trans,
			struct btrfs_root *root, struct btrfs_path *path,
			struct btrfs_key *key, const char *name,
			int name_len, int mod)
{ … }

/*
 * Lookup for a directory item by name.
 *
 * @trans:	The transaction handle to use. Can be NULL if @mod is 0.
 * @root:	The root of the target tree.
 * @path:	Path to use for the search.
 * @dir:	The inode number (objectid) of the directory.
 * @name:	The name associated to the directory entry we are looking for.
 * @name_len:	The length of the name.
 * @mod:	Used to indicate if the tree search is meant for a read only
 *		lookup, for a modification lookup or for a deletion lookup, so
 *		its value should be 0, 1 or -1, respectively.
 *
 * Returns: NULL if the dir item does not exists, an error pointer if an error
 * happened, or a pointer to a dir item if a dir item exists for the given name.
 */
struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
					     struct btrfs_root *root,
					     struct btrfs_path *path, u64 dir,
					     const struct fscrypt_str *name,
					     int mod)
{ … }

int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
				   const struct fscrypt_str *name)
{ … }

/*
 * Lookup for a directory index item by name and index number.
 *
 * @trans:	The transaction handle to use. Can be NULL if @mod is 0.
 * @root:	The root of the target tree.
 * @path:	Path to use for the search.
 * @dir:	The inode number (objectid) of the directory.
 * @index:	The index number.
 * @name:	The name associated to the directory entry we are looking for.
 * @name_len:	The length of the name.
 * @mod:	Used to indicate if the tree search is meant for a read only
 *		lookup, for a modification lookup or for a deletion lookup, so
 *		its value should be 0, 1 or -1, respectively.
 *
 * Returns: NULL if the dir index item does not exists, an error pointer if an
 * error happened, or a pointer to a dir item if the dir index item exists and
 * matches the criteria (name and index number).
 */
struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root,
			    struct btrfs_path *path, u64 dir,
			    u64 index, const struct fscrypt_str *name, int mod)
{ … }

struct btrfs_dir_item *
btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
			    u64 dirid, const struct fscrypt_str *name)
{ … }

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)
{ … }

/*
 * 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,
						 const struct btrfs_path *path,
						 const char *name, int name_len)
{ … }

/*
 * 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,
			      const struct btrfs_dir_item *di)
{ … }