On 10 April 2015 at 18:48, Viacheslav Dubeyko <slava@xxxxxxxxxxx> wrote:
> On Fri, 2015-04-10 at 11:02 +0200, Sergei Antonov wrote:
>> Function hfsplus_submit_bio() did not work when the passed buffer spanned
>> over more than one page. That was because bio_alloc() is passed 1 as a number
>> of vectors but more than one vector were added inside the 'while' loop.
>> It periodically caused a mount error when the volume header could not be read.
>>
>> This patch modifies the code so that only one vector is used. It works for
>> multiple pages too. Also adds a return code check after bio_alloc().
>
> I think that it really makes sense to describe the issue's reproducing
> way. It will be really precious for understanding of symptoms and
> reasons of the issue.
>
> Could you add more detailed description?
>
> Then, I will have opportunity to test your patch.
Well, the description says it all. To put it bluntly, when this line
from wrapper.c
sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
assigns s_vhdr_buf a value satisfying condition (PAGE_SIZE - (value &
PAGE_SIZE) < 512) then this call (also from wrapper.c) returns an
error:
error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
READ);
To give a specific example, sbi->s_vhdr_buf equal to
0xffff8804085acec0 spans two pages and hfsplus_submit_bio() can not
read into such a buffer, returns an error, mount operation fails.
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
