Re: Kernel 3.1.0-rc4 oops when connecting iPod

[Pavel Ivanov]

On Mon, Sep 12, 2011 at 10:34 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> Does this patch fix your issues with large block sizes?

I'll be able to try it in the evening but meanwhile I have some comments below.

>
>
> Index: linux-2.6/fs/hfsplus/super.c
> ===================================================================
> --- linux-2.6.orig/fs/hfsplus/super.c   2011-09-12 09:56:58.619988416 -0400
> +++ linux-2.6/fs/hfsplus/super.c        2011-09-12 10:07:18.006651395 -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;

Did you mix left and right shifts here? Expression doesn't make sense to me.

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() ?

> +
> +       if ((last_fs_block > (sector_t)(~0ULL) >> (sbi->alloc_blksz_shift - 9)) ||

Maybe this 9 should be extracted from here and
generic_check_addressable() into some macro?

> +           (last_fs_page > (pgoff_t)(~0ULL))) {
>                printk(KERN_ERR "hfs: filesystem size too large.\n");
>                goto out_free_vhdr;
>        }
>
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