/*
 *  linux/fs/adfs/dir_fplus.c
 *
 *  Copyright (C) 1997-1999 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include "adfs.h"
#include "dir_fplus.h"

static int
adfs_fplus_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
{
        struct adfs_bigdirheader *h;
        struct adfs_bigdirtail *t;
        unsigned long block;
        unsigned int blk, size;
        int i, ret = -EIO;

        dir->nr_buffers = 0;

        /* start off using fixed bh set - only alloc for big dirs */
        dir->bh_fplus = &dir->bh[0];

        block = __adfs_block_map(sb, id, 0);
        if (!block) {
                adfs_error(sb, "dir object %X has a hole at offset 0", id);
                goto out;
        }

        dir->bh_fplus[0] = sb_bread(sb, block);
        if (!dir->bh_fplus[0])
                goto out;
        dir->nr_buffers += 1;

        h = (struct adfs_bigdirheader *)dir->bh_fplus[0]->b_data;
        size = le32_to_cpu(h->bigdirsize);
        if (size != sz) {
                printk(KERN_WARNING "adfs: adfs_fplus_read:"
                                        " directory header size %X\n"
                                        " does not match directory size %X\n",
                                        size, sz);
        }

        if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
            h->bigdirversion[2] != 0 || size & 2047 ||
            h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME)) {
                printk(KERN_WARNING "adfs: dir object %X has"
                                        " malformed dir header\n", id);
                goto out;
        }

        size >>= sb->s_blocksize_bits;
        if (size > sizeof(dir->bh)/sizeof(dir->bh[0])) {
                /* this directory is too big for fixed bh set, must allocate */
                struct buffer_head **bh_fplus =
                        kzalloc(size * sizeof(struct buffer_head *),
                                GFP_KERNEL);
                if (!bh_fplus) {
                        adfs_error(sb, "not enough memory for"
                                        " dir object %X (%d blocks)", id, size);
                        goto out;
                }
                dir->bh_fplus = bh_fplus;
                /* copy over the pointer to the block that we've already read */
                dir->bh_fplus[0] = dir->bh[0];
        }

        for (blk = 1; blk < size; blk++) {
                block = __adfs_block_map(sb, id, blk);
                if (!block) {
                        adfs_error(sb, "dir object %X has a hole at offset %d", id, blk);
                        goto out;
                }

                dir->bh_fplus[blk] = sb_bread(sb, block);
                if (!dir->bh_fplus[blk]) {
                        adfs_error(sb,  "dir object %X failed read for"
                                        " offset %d, mapped block %X",
                                        id, blk, block);
                        goto out;
                }

                dir->nr_buffers += 1;
        }

        t = (struct adfs_bigdirtail *)
                (dir->bh_fplus[size - 1]->b_data + (sb->s_blocksize - 8));

        if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
            t->bigdirendmasseq != h->startmasseq ||
            t->reserved[0] != 0 || t->reserved[1] != 0) {
                printk(KERN_WARNING "adfs: dir object %X has "
                                        "malformed dir end\n", id);
                goto out;
        }

        dir->parent_id = le32_to_cpu(h->bigdirparent);
        dir->sb = sb;
        return 0;

out:
        if (dir->bh_fplus) {
                for (i = 0; i < dir->nr_buffers; i++)
                        brelse(dir->bh_fplus[i]);

                if (&dir->bh[0] != dir->bh_fplus)
                        kfree(dir->bh_fplus);

                dir->bh_fplus = NULL;
        }

        dir->nr_buffers = 0;
        dir->sb = NULL;
        return ret;
}

static int
adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
{
        struct adfs_bigdirheader *h =
                (struct adfs_bigdirheader *) dir->bh_fplus[0]->b_data;
        int ret = -ENOENT;

        if (fpos <= le32_to_cpu(h->bigdirentries)) {
                dir->pos = fpos;
                ret = 0;
        }

        return ret;
}

static void
dir_memcpy(struct adfs_dir *dir, unsigned int offset, void *to, int len)
{
        struct super_block *sb = dir->sb;
        unsigned int buffer, partial, remainder;

        buffer = offset >> sb->s_blocksize_bits;
        offset &= sb->s_blocksize - 1;

        partial = sb->s_blocksize - offset;

        if (partial >= len)
                memcpy(to, dir->bh_fplus[buffer]->b_data + offset, len);
        else {
                char *c = (char *)to;

                remainder = len - partial;

                memcpy(c,
                        dir->bh_fplus[buffer]->b_data + offset,
                        partial);

                memcpy(c + partial,
                        dir->bh_fplus[buffer + 1]->b_data,
                        remainder);
        }
}

static int
adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
{
        struct adfs_bigdirheader *h =
                (struct adfs_bigdirheader *) dir->bh_fplus[0]->b_data;
        struct adfs_bigdirentry bde;
        unsigned int offset;
        int i, ret = -ENOENT;

        if (dir->pos >= le32_to_cpu(h->bigdirentries))
                goto out;

        offset = offsetof(struct adfs_bigdirheader, bigdirname);
        offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
        offset += dir->pos * sizeof(struct adfs_bigdirentry);

        dir_memcpy(dir, offset, &bde, sizeof(struct adfs_bigdirentry));

        obj->loadaddr = le32_to_cpu(bde.bigdirload);
        obj->execaddr = le32_to_cpu(bde.bigdirexec);
        obj->size     = le32_to_cpu(bde.bigdirlen);
        obj->file_id  = le32_to_cpu(bde.bigdirindaddr);
        obj->attr     = le32_to_cpu(bde.bigdirattr);
        obj->name_len = le32_to_cpu(bde.bigdirobnamelen);

        offset = offsetof(struct adfs_bigdirheader, bigdirname);
        offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
        offset += le32_to_cpu(h->bigdirentries) * sizeof(struct adfs_bigdirentry);
        offset += le32_to_cpu(bde.bigdirobnameptr);

        dir_memcpy(dir, offset, obj->name, obj->name_len);
        for (i = 0; i < obj->name_len; i++)
                if (obj->name[i] == '/')
                        obj->name[i] = '.';

        obj->filetype = -1;

        /*
         * object is a file and is filetyped and timestamped?
         * RISC OS 12-bit filetype is stored in load_address[19:8]
         */
        if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
                (0xfff00000 == (0xfff00000 & obj->loadaddr))) {
                obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);

                /* optionally append the ,xyz hex filetype suffix */
                if (ADFS_SB(dir->sb)->s_ftsuffix)
                        obj->name_len +=
                                append_filetype_suffix(
                                        &obj->name[obj->name_len],
                                        obj->filetype);
        }

        dir->pos += 1;
        ret = 0;
out:
        return ret;
}

static int
adfs_fplus_sync(struct adfs_dir *dir)
{
        int err = 0;
        int i;

        for (i = dir->nr_buffers - 1; i >= 0; i--) {
                struct buffer_head *bh = dir->bh_fplus[i];
                sync_dirty_buffer(bh);
                if (buffer_req(bh) && !buffer_uptodate(bh))
                        err = -EIO;
        }

        return err;
}

static void
adfs_fplus_free(struct adfs_dir *dir)
{
        int i;

        if (dir->bh_fplus) {
                for (i = 0; i < dir->nr_buffers; i++)
                        brelse(dir->bh_fplus[i]);

                if (&dir->bh[0] != dir->bh_fplus)
                        kfree(dir->bh_fplus);

                dir->bh_fplus = NULL;
        }

        dir->nr_buffers = 0;
        dir->sb = NULL;
}

struct adfs_dir_ops adfs_fplus_dir_ops = {
        .read           = adfs_fplus_read,
        .setpos         = adfs_fplus_setpos,
        .getnext        = adfs_fplus_getnext,
        .sync           = adfs_fplus_sync,
        .free           = adfs_fplus_free
};