// SPDX-License-Identifier: GPL-2.0
/*
 * QNX4 file system, Linux implementation.
 *
 * Version : 0.2.1
 *
 * Using parts of the xiafs filesystem.
 *
 * History :
 *
 * 28-05-1998 by Richard Frowijn : first release.
 * 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support.
 */

#include <linux/buffer_head.h>
#include <linux/filelock.h>
#include "qnx4.h"

static int qnx4_readdir(struct file *file, struct dir_context *ctx)
{
        struct inode *inode = file_inode(file);
        unsigned int offset;
        struct buffer_head *bh;
        unsigned long blknum;
        int ix, ino;
        int size;

        QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size));
        QNX4DEBUG((KERN_INFO "pos                 = %ld\n", (long) ctx->pos));

        while (ctx->pos < inode->i_size) {
                blknum = qnx4_block_map(inode, ctx->pos >> QNX4_BLOCK_SIZE_BITS);
                bh = sb_bread(inode->i_sb, blknum);
                if (bh == NULL) {
                        printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum);
                        return 0;
                }
                ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK;
                for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) {
                        union qnx4_directory_entry *de;
                        const char *fname;

                        offset = ix * QNX4_DIR_ENTRY_SIZE;
                        de = (union qnx4_directory_entry *) (bh->b_data + offset);

                        fname = get_entry_fname(de, &size);
                        if (!fname)
                                continue;

                        if (!(de->de_status & QNX4_FILE_LINK)) {
                                ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1;
                        } else {
                                ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) *
                                        QNX4_INODES_PER_BLOCK +
                                        de->link.dl_inode_ndx;
                        }

                        QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, fname));
                        if (!dir_emit(ctx, fname, size, ino, DT_UNKNOWN)) {
                                brelse(bh);
                                return 0;
                        }
                }
                brelse(bh);
        }
        return 0;
}

const struct file_operations qnx4_dir_operations =
{
        .llseek         = generic_file_llseek,
        .read           = generic_read_dir,
        .iterate_shared = qnx4_readdir,
        .fsync          = generic_file_fsync,
        .setlease       = generic_setlease,
};

const struct inode_operations qnx4_dir_inode_operations =
{
        .lookup         = qnx4_lookup,
};