Re: Kernel 3.1.0-rc4 oops when connecting iPod

[Pavel Ivanov]

On Mon, Sep 12, 2011 at 11:31 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> Yes, the shifts were the wrong way around.  I'll leave the 9 in for now,
> we use it in so many places and if we're going to clean it up I'd do it
> in ne go.
>
> Index: linux-2.6/fs/hfsplus/super.c
> ===================================================================
> --- linux-2.6.orig/fs/hfsplus/super.c   2011-09-12 11:20:33.866598100 -0400
> +++ linux-2.6/fs/hfsplus/super.c        2011-09-12 11:20:52.538098052 -0400
> @@ -344,6 +344,7 @@ static int hfsplus_fill_super(struct sup
>        struct inode *root, *inode;
>        struct qstr str;
>        struct nls_table *nls = NULL;
> +       u64 last_fs_block, last_fs_page;
>        int err;
>
>        err = -EINVAL;
> @@ -399,9 +400,13 @@ static int hfsplus_fill_super(struct sup
>        if (!sbi->rsrc_clump_blocks)
>                sbi->rsrc_clump_blocks = 1;
>
> -       err = generic_check_addressable(sbi->alloc_blksz_shift,
> -                                       sbi->total_blocks);
> -       if (err) {
> +       err = -EFBIG;
> +       last_fs_block = sbi->total_blocks - 1;
> +       last_fs_page = (last_fs_block << sbi->alloc_blksz_shift) >>
> +                       PAGE_CACHE_SHIFT;
> +
> +       if ((last_fs_block > (sector_t)(~0ULL) >> (sbi->alloc_blksz_shift - 9)) ||
> +           (last_fs_page > (pgoff_t)(~0ULL))) {
>                printk(KERN_ERR "hfs: filesystem size too large.\n");
>                goto out_free_vhdr;
>        }
>

Christoph,

This patch works for me.

And could you comment on my PAGE_SIZE question?

>> Also I have a little concern about consistency in using
>> PAGE_CACHE_SHIFT and PAGE_SHIFT. hfsplus_read_wrapper() limits visible
>> block size to PAGE_SIZE, not PAGE_CACHE_SIZE. And although now they
>> are equal comment in linux/pagemap.h clearly says that PAGE_CACHE_SIZE
>> can be bigger than PAGE_SIZE. Is it something that should be fixed in
>> hfsplus_read_wrapper() ?
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