linux/fs/afs/dir_edit.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS filesystem directory editing
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 */

#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/iversion.h>
#include "internal.h"
#include "xdr_fs.h"

/*
 * Find a number of contiguous clear bits in a directory block bitmask.
 *
 * There are 64 slots, which means we can load the entire bitmap into a
 * variable.  The first bit doesn't count as it corresponds to the block header
 * slot.  nr_slots is between 1 and 9.
 */
static int afs_find_contig_bits(union afs_xdr_dir_block *block, unsigned int nr_slots)
{ … }

/*
 * Set a number of contiguous bits in the directory block bitmap.
 */
static void afs_set_contig_bits(union afs_xdr_dir_block *block,
				int bit, unsigned int nr_slots)
{ … }

/*
 * Clear a number of contiguous bits in the directory block bitmap.
 */
static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
				  int bit, unsigned int nr_slots)
{ … }

/*
 * Get a new directory folio.
 */
static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index)
{ … }

/*
 * Scan a directory block looking for a dirent of the right name.
 */
static int afs_dir_scan_block(union afs_xdr_dir_block *block, struct qstr *name,
			      unsigned int blocknum)
{ … }

/*
 * Initialise a new directory block.  Note that block 0 is special and contains
 * some extra metadata.
 */
static void afs_edit_init_block(union afs_xdr_dir_block *meta,
				union afs_xdr_dir_block *block, int block_num)
{ … }

/*
 * Edit a directory's file data to add a new directory entry.  Doing this after
 * create, mkdir, symlink, link or rename if the data version number is
 * incremented by exactly one avoids the need to re-download the entire
 * directory contents.
 *
 * The caller must hold the inode locked.
 */
void afs_edit_dir_add(struct afs_vnode *vnode,
		      struct qstr *name, struct afs_fid *new_fid,
		      enum afs_edit_dir_reason why)
{ … }

/*
 * Edit a directory's file data to remove a new directory entry.  Doing this
 * after unlink, rmdir or rename if the data version number is incremented by
 * exactly one avoids the need to re-download the entire directory contents.
 *
 * The caller must hold the inode locked.
 */
void afs_edit_dir_remove(struct afs_vnode *vnode,
			 struct qstr *name, enum afs_edit_dir_reason why)
{ … }