Re: [PATCH v8 06/19] block, fs: Propagate write hints to the block device inode

Bart Van Assche
2024-01-22T20:09:08Z

On 1/22/24 01:31, Kanchan Joshi wrote:
> On 1/19/2024 7:26 PM, Kanchan Joshi wrote:
>> On 1/19/2024 12:24 AM, Bart Van Assche wrote:
>>> I think the above proposal would introduce a bug: it would break the
>>> F_GET_RW_HINT implementation.
>>
>> Right. I expected to keep the exact change in GET, too, but that will
>> not be free from the side-effect.
>> The buffered-write path (block_write_full_page) picks the hint from one
>> inode, and the direct-write path (__blkdev_direct_IO_simple) picks the
>> hint from a different inode.
>> So, updating both seems needed here.
>
> I stand corrected. It's possible to do away with two updates.
> The direct-io code (patch 8) should rather be changed to pick the hint
> from bdev inode (and not from file inode).
> With that change, this patch only need to set the hint into only one
> inode (bdev one). What do you think?

I think that would break direct I/O submitted by a filesystem.

Bart.