Re: [PATCH] direct-io: don't introduce another read of inode->i_blkbits

From: Jens Axboe
Date: Mon Jan 09 2017 - 16:44:58 EST


On 01/09/2017 02:42 PM, Jeff Moyer wrote:
> Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
> block count to be cleaned") introduced a regression: if the block size
> of the block device is changed while a direct I/O request is being
> setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
> don't read inode->i_blkbits multiple times") for the reasoning, and
> commit b87570f5d3496 ("Fix a crash when block device is read and block
> size is changed at the same time") for a more detailed problem
> description and reproducer.
>
> Fixes: 20ce44d545844
> Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
>
> ---
> Chandan, can you please test this to ensure this still fixes your problem?

Please, that would be great. And if so, then let's fold the two.

--
Jens Axboe