linux/fs/reiserfs/tail_conversion.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
 * details
 */

#include <linux/time.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include "reiserfs.h"

/*
 * access to tail : when one is going to read tail it must make sure, that is
 * not running.  direct2indirect and indirect2direct can not run concurrently
 */

/*
 * Converts direct items to an unformatted node. Panics if file has no
 * tail. -ENOSPC if no disk space for conversion
 */
/*
 * path points to first direct item of the file regardless of how many of
 * them are there
 */
int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
		    struct treepath *path, struct buffer_head *unbh,
		    loff_t tail_offset)
{ … }

/* stolen from fs/buffer.c */
void reiserfs_unmap_buffer(struct buffer_head *bh)
{ … }

/*
 * this first locks inode (neither reads nor sync are permitted),
 * reads tail through page cache, insert direct item. When direct item
 * inserted successfully inode is left locked. Return value is always
 * what we expect from it (number of cut bytes). But when tail remains
 * in the unformatted node, we set mode to SKIP_BALANCING and unlock
 * inode
 */
int indirect2direct(struct reiserfs_transaction_handle *th,
		    struct inode *inode, struct page *page,
		    struct treepath *path,	/* path to the indirect item. */
		    const struct cpu_key *item_key,	/* Key to look for
							 * unformatted node
							 * pointer to be cut. */
		    loff_t n_new_file_size,	/* New file size. */
		    char *mode)
{ … }