Re: [PATCH] make affs root lookup from blkdev logical size

[Andrew Morton <akpm@linux-foundation.org>]

On Tue,  7 Jul 2015 12:29:02 +0530 "Pranay Kr. Srivastava" <pranjas@gmail.com> wrote:

> This patch resolves Bug 16531. When logical blkdev
> size > 512 then sector numbers become larger than
> the device can support.
> 
> Make affs start lookup based on the device's logical
> sector size instead of 512.
> 
> Reported By: Mark <markk@clara.co.uk>
> Fix Suggessted By: Mark <markk@clara.co.uk>

Can you please send your Signed-off-by: for this?  It is described in
Documentation/SubmittingPatches section 11.

> --- a/fs/affs/super.c
> +++ b/fs/affs/super.c
> @@ -18,6 +18,7 @@
>  #include <linux/sched.h>
>  #include <linux/slab.h>
>  #include <linux/writeback.h>
> +#include <linux/blkdev.h>
>  #include "affs.h"
>  
>  static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
> @@ -352,18 +353,19 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
>  	 * blocks, we will have to change it.
>  	 */
>  
> -	size = sb->s_bdev->bd_inode->i_size >> 9;
> +	size = i_size_read(sb->s_bdev->bd_inode) >> 9;
>  	pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
>  
>  	affs_set_blocksize(sb, PAGE_SIZE);
>  	/* Try to find root block. Its location depends on the block size. */
>  
> -	i = 512;
> -	j = 4096;
> +	i = bdev_logical_block_size(sb->s_bdev);
> +	j = PAGE_SIZE;

Some architectures have PAGE_SIZE larger than 4k.  What effect will
that have?

>  	if (blocksize > 0) {
>  		i = j = blocksize;
>  		size = size / (blocksize / 512);
>  	}
> +
>  	for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
>  		sbi->s_root_block = root_block;
>  		if (root_block < 0)