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

[Jens Axboe]

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 at redhat.com>
> 
> ---
> 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