Re: [PATCH v8 05/19] block, fs: Restore the per-bio/request data lifetime fields

Kanchan Joshi
2024-01-23T12:35:32Z

On 1/23/2024 1:35 AM, Bart Van Assche wrote:
> On 1/22/24 01:23, Kanchan Joshi wrote:
>> On 12/19/2023 5:37 AM, Bart Van Assche wrote:
>>
>>> diff --git a/block/fops.c b/block/fops.c
>>> index 0abaac705daf..787ce52bc2c6 100644
>>> --- a/block/fops.c
>>> +++ b/block/fops.c
>>> @@ -73,6 +73,7 @@ static ssize_t __blkdev_direct_IO_simple(struct
>>> kiocb *iocb,
>>>            bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
>>>        }
>>>        bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
>>> +    bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
>>>        bio.bi_ioprio = iocb->ki_ioprio;
>>>        ret = bio_iov_iter_get_pages(&bio, iter);
>>> @@ -203,6 +204,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb
>>> *iocb, struct iov_iter *iter,
>>>        for (;;) {
>>>            bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
>>> +        bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
>>>            bio->bi_private = dio;
>>>            bio->bi_end_io = blkdev_bio_end_io;
>>>            bio->bi_ioprio = iocb->ki_ioprio;
>>> @@ -321,6 +323,7 @@ static ssize_t __blkdev_direct_IO_async(struct
>>> kiocb *iocb,
>>>        dio->flags = 0;
>>>        dio->iocb = iocb;
>>>        bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
>>> +    bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
>>
>> This (and two more places above) should rather be changed to:
>>
>> bio.bi_write_hint = bdev_file_inode(iocb->ki_filp)->i_write_hint;
>>
>> Note that at other places too (e.g., blkdev_fallocate, blkdev_mmap,
>> blkdev_lseek) bdev inode is used and not file inode.
>
> Why should this code be changed?

Because this file is for raw block IO, and bdev_file_inode is the right
inode to be used.

> The above code has been tested and
> works fine.

At the cost of inviting some extra work. Because this patch used
file_inode, the patch 6 needs to set the hint on two inodes.
If we use bdev_file_inode, this whole thing becomes clean.