linux/fs/sysv/dir.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/sysv/dir.c
 *
 *  minix/dir.c
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  coh/dir.c
 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
 *
 *  sysv/dir.c
 *  Copyright (C) 1993  Bruno Haible
 *
 *  SystemV/Coherent directory handling functions
 */

#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include "sysv.h"

static int sysv_readdir(struct file *, struct dir_context *);

const struct file_operations sysv_dir_operations = …;

static void dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
{ … }

static int sysv_handle_dirsync(struct inode *dir)
{ … }

/*
 * Calls to dir_get_page()/unmap_and_put_page() must be nested according to the
 * rules documented in mm/highmem.rst.
 *
 * NOTE: sysv_find_entry() and sysv_dotdot() act as calls to dir_get_page()
 * and must be treated accordingly for nesting purposes.
 */
static void *dir_get_page(struct inode *dir, unsigned long n, struct page **p)
{ … }

static int sysv_readdir(struct file *file, struct dir_context *ctx)
{ … }

/* compare strings: name[0..len-1] (not zero-terminated) and
 * buffer[0..] (filled with zeroes up to buffer[0..maxlen-1])
 */
static inline int namecompare(int len, int maxlen,
	const char * name, const char * buffer)
{ … }

/*
 *	sysv_find_entry()
 *
 * finds an entry in the specified directory with the wanted name. It
 * returns the cache buffer in which the entry was found, and the entry
 * itself (as a parameter - res_dir). It does NOT read the inode of the
 * entry - you'll have to do that yourself if you want to.
 *
 * On Success unmap_and_put_page() should be called on *res_page.
 *
 * sysv_find_entry() acts as a call to dir_get_page() and must be treated
 * accordingly for nesting purposes.
 */
struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page)
{ … }

int sysv_add_link(struct dentry *dentry, struct inode *inode)
{ … }

int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
{ … }

int sysv_make_empty(struct inode *inode, struct inode *dir)
{ … }

/*
 * routine to check that the specified directory is empty (for rmdir)
 */
int sysv_empty_dir(struct inode * inode)
{ … }

/* Releases the page */
int sysv_set_link(struct sysv_dir_entry *de, struct page *page,
	struct inode *inode)
{ … }

/*
 * Calls to dir_get_page()/unmap_and_put_page() must be nested according to the
 * rules documented in mm/highmem.rst.
 *
 * sysv_dotdot() acts as a call to dir_get_page() and must be treated
 * accordingly for nesting purposes.
 */
struct sysv_dir_entry *sysv_dotdot(struct inode *dir, struct page **p)
{ … }

ino_t sysv_inode_by_name(struct dentry *dentry)
{ … }