Re: [PATCH] add I/O error uevent for block devices

[Andrew Morton <akpm@osdl.org>]

Kay Sievers <kay.sievers@vrfy.org> wrote:
>
> For HAL we want to get notified about I/O errors of block devices.
>  This is especially useful for devices we are unable to poll and
>  therefore can't know if something goes wrong here.
> 
>  Signed-off-by: David Zeuthen <david@fubar.dk>
>  Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
> 
>  ===== fs/buffer.c 1.270 vs edited =====
>  --- 1.270/fs/buffer.c	2005-01-21 06:02:13 +01:00
>  +++ edited/fs/buffer.c	2005-02-17 22:56:05 +01:00
>  @@ -105,6 +105,7 @@ static void buffer_io_error(struct buffe
>   	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
>   			bdevname(bh->b_bdev, b),
>   			(unsigned long long)bh->b_blocknr);
>  +	kobject_uevent(&bh->b_bdev->bd_disk->kobj, KOBJ_IO_ERROR, NULL);
>   }

- buffer_io_error() is called from interrupt context, and
  kobject_uevent() does multiple GFP_KERNEL allocations.  You'll need to
  use kobject_uevent_atomic().

- the prink_ratelimit() fix in end_buffer_async_read() should be a
  separate patch, really.  I'll fix that up.

- there are numerous other places where an I/O error can be detected:
  grep the tree for b_end_io and bio_end_io.