Re: [PATCH 07/10] AXFS: axfs_bdev.c

MinChan Kim
2008-08-24T08:20:00Z

On Thu, Aug 21, 2008 at 2:45 PM, Jared Hulbert <jaredeh@gmail.com> wrote:
> All the block device code goes here.
>
> Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
> ---
> diff --git a/fs/axfs/axfs_bdev.c b/fs/axfs/axfs_bdev.c
> new file mode 100644
> index 0000000..4c6f83c
> --- /dev/null
> +++ b/fs/axfs/axfs_bdev.c
> @@ -0,0 +1,158 @@
> +/*
> + * Advanced XIP File System for Linux - AXFS
> + * Readonly, compressed, and XIP filesystem for Linux systems big and small
> + *
> + * Copyright(c) 2008 Numonyx
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * Authors:
> + * Jared Hulbert <jaredeh@gmail.com>
> + *
> + * Project url: http://axfs.sourceforge.net
> + *
> + * axfs_bdev.c -
> + * Allows axfs to use block devices or has dummy functions if block
> + * device support is compiled out of the kernel.
> + *
> + */
> +
> +#include <linux/axfs.h>
> +#include <linux/mount.h>
> +#ifdef CONFIG_BLOCK
> +#include <linux/buffer_head.h>
> +#include <linux/namei.h>
> +
> +int axfs_fill_super(struct super_block *sb, void *data, int silent);
> +
> +int axfs_get_sb_bdev(struct file_system_type *fs_type, int flags,
> + const char *dev_name, struct axfs_super *sbi,
> + struct vfsmount *mnt, int *err)
> +{
> + *err = get_sb_bdev(fs_type, flags, dev_name, sbi, axfs_fill_super, mnt);
> +
> + if (*err)
> + return FALSE;
> + return TRUE;
> +}
> +
> +void axfs_kill_block_super(struct super_block *sb)
> +{
> + kill_block_super(sb);
> +}
> +
> +/******************************************************************************
> + *
> + * axfs_copy_block_data
> + *
> + * Description: Helper function to read data from block device
> + *
> + * Parameters:
> + * (IN) sb - pointer to super block structure.
> + *
> + * (IN) dst_addr - pointer to buffer into which data is to be read.
> + *
> + * (IN) boffset - offset within block device
> + *
> + * (IN) len - length of data to be read
> + *
> + * Returns:
> + * 0 or error number
> + *
> + *****************************************************************************/
> +int axfs_copy_block(struct super_block *sb, void *dst_addr, u64 fsoffset,
> + u64 len)
> +{
> + struct axfs_super *sbi = AXFS_SB(sb);
> + u64 boffset = AXFS_FSOFFSET_2_DEVOFFSET(sbi, fsoffset);
> + u64 blocks;
> + u64 blksize = sb->s_blocksize;
> + unsigned long dst;
> + unsigned long src;
> + sector_t block;
> + size_t bytes;
> + struct buffer_head *bh;
> + u64 copied = 0;
> +
> + if (len == 0)
> + return 0;
> +
> + blocks = len / blksize;
> + if ((len % blksize) > 0)
> + blocks += 1;

blocks ??
You have to drop blocks variable since anyone don't use it.

> + while (copied < len) {
> + /* Explicit casting for ARM linker errors. */
> + block = (sector_t) boffset + (sector_t) copied;
> + block /= (sector_t) blksize;
> + bh = sb_bread(sb, block);
> + src = (unsigned long)bh->b_data;
> + dst = (unsigned long)dst_addr;
> + if (copied == 0) {
> + /* Explicit casting for ARM linker errors. */
> + bytes = (size_t) blksize;
> + bytes -= (size_t) boffset % (size_t) blksize;
> + if (bytes > len)
> + bytes = len;
> + /* Explicit casting for ARM linker errors. */
> + src += (unsigned long)boffset % (unsigned long)blksize;
> + } else {
> + dst += copied;
> + if ((len - copied) < blksize) {
> + bytes = len - copied;
> + } else {
> + bytes = blksize;
> + }
> + }
> + memcpy((void *)dst, (void *)src, bytes);
> + copied += bytes;
> + brelse(bh);
> + }
> + return 0;
> +}
> +
> +int axfs_is_dev_bdev(char *path)
> +{
> + struct nameidata nd;
> + int ret = FALSE;
> +
> + if (!path)
> + return FALSE;
> +
> + if (path_lookup(path, LOOKUP_FOLLOW, &nd))
> + return FALSE;
> +
> + if (S_ISBLK(nd.path.dentry->d_inode->i_mode))
> + ret = TRUE;
> +
> + path_put(&nd.path);
> + return ret;
> +}
> +
> +#else
> +
> +int axfs_get_sb_bdev(struct file_system_type *fs_type, int flags,
> + const char *dev_name, struct axfs_super *sbi,
> + struct vfsmount *mnt, int *err)
> +{
> + return FALSE;
> +}
> +
> +void axfs_kill_block_super(struct super_block *sb)
> +{
> +}
> +
> +int axfs_copy_block(struct super_block *sb, void *dst_addr, u64 fsoffset,
> + u64 len)
> +{
> + return -EINVAL;
> +}
> +
> +int axfs_is_dev_bdev(char *path)
> +{
> + return FALSE;
> +}
> +
> +#endif /* CONFIG_BLOCK */
>
>
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--
Kinds regards,
MinChan Kim