linux/fs/adfs/inode.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/fs/adfs/inode.c
 *
 *  Copyright (C) 1997-1999 Russell King
 */
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/writeback.h>
#include "adfs.h"

/*
 * Lookup/Create a block at offset 'block' into 'inode'.  We currently do
 * not support creation of new blocks, so we return -EIO for this case.
 */
static int
adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
	       int create)
{ … }

static int adfs_writepages(struct address_space *mapping,
		struct writeback_control *wbc)
{ … }

static int adfs_read_folio(struct file *file, struct folio *folio)
{ … }

static void adfs_write_failed(struct address_space *mapping, loff_t to)
{ … }

static int adfs_write_begin(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len,
			struct page **pagep, void **fsdata)
{ … }

static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
{ … }

static const struct address_space_operations adfs_aops = …;

/*
 * Convert ADFS attributes and filetype to Linux permission.
 */
static umode_t
adfs_atts2mode(struct super_block *sb, struct inode *inode)
{ … }

/*
 * Convert Linux permission to ADFS attribute.  We try to do the reverse
 * of atts2mode, but there is not a 1:1 translation.
 */
static int adfs_mode2atts(struct super_block *sb, struct inode *inode,
			  umode_t ia_mode)
{ … }

static const s64 nsec_unix_epoch_diff_risc_os_epoch = …;

/*
 * Convert an ADFS time to Unix time.  ADFS has a 40-bit centi-second time
 * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds
 * of time to convert from RISC OS epoch to Unix epoch.
 */
static void
adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode)
{ … }

/* Convert an Unix time to ADFS time for an entry that is already stamped. */
static void adfs_unix2adfs_time(struct inode *inode,
				const struct timespec64 *ts)
{ … }

/*
 * Fill in the inode information from the object information.
 *
 * Note that this is an inode-less filesystem, so we can't use the inode
 * number to reference the metadata on the media.  Instead, we use the
 * inode number to hold the object ID, which in turn will tell us where
 * the data is held.  We also save the parent object ID, and with these
 * two, we can locate the metadata.
 *
 * This does mean that we rely on an objects parent remaining the same at
 * all times - we cannot cope with a cross-directory rename (yet).
 */
struct inode *
adfs_iget(struct super_block *sb, struct object_info *obj)
{ … }

/*
 * Validate and convert a changed access mode/time to their ADFS equivalents.
 * adfs_write_inode will actually write the information back to the directory
 * later.
 */
int
adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
		   struct iattr *attr)
{ … }

/*
 * write an existing inode back to the directory, and therefore the disk.
 * The adfs-specific inode data has already been updated by
 * adfs_notify_change()
 */
int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{ … }