Re: read corruption with qemu master io_uring engine / linux master / btrfs(?)

From: Dominique MARTINET <dominique.martinet@atmark-techno.com>
To: Filipe Manana <fdmanana@kernel.org>
Cc: Nikolay Borisov <nborisov@suse.com>, Jens Axboe <axboe@kernel.dk>,
	io-uring@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: read corruption with qemu master io_uring engine / linux master / btrfs(?)
Date: Fri, 1 Jul 2022 10:25:58 +0900	[thread overview]
Message-ID: <Yr5NJnyKoWqAHsad@atmark-techno.com> (raw)
In-Reply-To: <20220630151038.GA459423@falcondesktop>

Filipe Manana wrote on Thu, Jun 30, 2022 at 04:10:38PM +0100:
> This may prevent the short reads (not tested yet):
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 7a54f964ff37..42fb56ed0021 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7684,7 +7684,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
>         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
>             em->block_start == EXTENT_MAP_INLINE) {
>                 free_extent_map(em);
> -               ret = -ENOTBLK;
> +               ret = (flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOTBLK;
>                 goto unlock_err;
>         }
>  
> Can you give it a try?

This appears to do the trick!
I've also removed the first patch and still cannot see any short reads,
so this would be enough on its own for my case.

-- 
Dominique