Re: [PATCH] fs: guard_bio_eod() needs to consider partitions

[Al Viro]

On Mon, Oct 23, 2017 at 07:10:07PM -0600, Greg Edwards wrote:
> guard_bio_eod() needs to look at the partition capacity, not just the
> capacity of the whole device, when determining if truncation is
> necessary.
> 
> [   60.268688] attempt to access beyond end of device
> [   60.268690] unknown-block(9,1): rw=0, want=67103509, limit=67103506
> [   60.268693] buffer_io_error: 2 callbacks suppressed
> [   60.268696] Buffer I/O error on dev md1p7, logical block 4524305, async page read
> 
> Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and partitions index")
> Signed-off-by: Greg Edwards <gedwards@xxxxxxx>

That smells like a nasty source of overhead, especially on SMP boxen...