dir_fplus.c

Go to the documentation of this file.

/*
 *  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
};