Function ext3_bread

Ext4Fsd/ext3/htree.c:230–277

ext3_bread is safe for meta-data blocks. it's not safe to read file data, since file data is managed by file cache, not volume cache */

/* ext3_bread is safe for meta-data blocks. it's not safe to read file data,
   since file data is managed by file cache, not volume cache */
struct buffer_head *ext3_bread(struct ext2_icb *icb, struct inode *inode,
                                           unsigned long block, int *err)
{
    struct buffer_head * bh = NULL;
    NTSTATUS    status = STATUS_SUCCESS;
    ULONG       lbn = 0, num = 0;

    PEXT2_MCB   Mcb = CONTAINING_RECORD(inode, EXT2_MCB, Inode);

    /* for symlink file, read it's target instead */
    if (NULL != Mcb && IsMcbSymLink(Mcb))
        Mcb = Mcb->Target;
    if (NULL == Mcb) {
        *err = -EINVAL;
        return NULL;
    }

    /* mapping file offset to ext2 block */
    if (INODE_HAS_EXTENT(&Mcb->Inode)) {
        status = Ext2MapExtent(icb, inode->i_sb->s_priv,
                               Mcb, block, FALSE,
                               &lbn, &num);
    } else {
        status = Ext2MapIndirect(icb, inode->i_sb->s_priv,
                                 Mcb, block, FALSE,
                                 &lbn, &num);
    }

    if (!NT_SUCCESS(status)) {
        *err = Ext2LinuxError(status);
        return bh;
    }

    bh = sb_getblk(inode->i_sb, lbn);
    if (!bh) {
        *err = -ENOMEM;
        return bh;
    }
    if (buffer_uptodate(bh))
        return bh;

    *err = bh_submit_read(bh);
    if (*err) {
	    __brelse(bh);
	    return NULL;
    }
    return bh;
}

struct buffer_head *ext3_append(struct ext2_icb *icb, struct inode *inode,
                                            ext3_lblk_t *block, int *err)