Mailinglist Archive: packet-writing (42 mails)
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Re: ext2 on a CD-RW
- From: Jens Axboe <axboe@xxxxxxx>
- Date: Fri, 2 Jan 2004 10:09:19 +0000 (UTC)
- Message-id: <20040102100909.GG5523@xxxxxxx>
On Fri, Jan 02 2004, Arjan van de Ven wrote:
> On Fri, 2004-01-02 at 02:30, Peter Osterlund wrote:
>
> > The packet writing code has the restriction that a bio must not span a
> > packet boundary. (A packet is 32*2048 bytes.) If the page when mapped
> > to disk starts 2kb before a packet boundary, merge_bvec_fn therefore
> > returns 2048, which is less than len, which is 4096 if the whole page
> > is mapped, so the bio_add_page() call fails.
>
> devicemapper has similar restrictions for raid0 format; in that case
> it's device-mappers job to split the page/bio. Just as it is UDF's task
> to do the same I suspect...
It has nothing to do with UDF, it's a driver problem (API breakage).
--
Jens Axboe
> On Fri, 2004-01-02 at 02:30, Peter Osterlund wrote:
>
> > The packet writing code has the restriction that a bio must not span a
> > packet boundary. (A packet is 32*2048 bytes.) If the page when mapped
> > to disk starts 2kb before a packet boundary, merge_bvec_fn therefore
> > returns 2048, which is less than len, which is 4096 if the whole page
> > is mapped, so the bio_add_page() call fails.
>
> devicemapper has similar restrictions for raid0 format; in that case
> it's device-mappers job to split the page/bio. Just as it is UDF's task
> to do the same I suspect...
It has nothing to do with UDF, it's a driver problem (API breakage).
--
Jens Axboe
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