Re: [PATCH 2/2] iomap: bmap: Remove the WARN and return the proper block address

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Apr 24, 2020 at 12:52:18PM +0530, Ritesh Harjani wrote:
> iomap_bmap() could be called from either of these two paths.
> Either when a user is calling an ioctl_fibmap() interface to get
> the block mapping address or by some filesystem via use of bmap()
> internal kernel API.
> bmap() kernel API is well equipped with handling of u64 addresses.
> 
> WARN condition in iomap_bmap_actor() was mainly added to warn all
> the fibmap users. But now that in previous patch we have directly added
> this WARN condition for all fibmap users and also made sure to return 0
> as block map address in case if addr > INT_MAX. 
> So we can now remove this logic from here.
> 
> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
> ---
>  fs/iomap/fiemap.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c
> index bccf305ea9ce..d55e8f491a5e 100644
> --- a/fs/iomap/fiemap.c
> +++ b/fs/iomap/fiemap.c
> @@ -117,10 +117,7 @@ iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
>  
>  	if (iomap->type == IOMAP_MAPPED) {
>  		addr = (pos - iomap->offset + iomap->addr) >> inode->i_blkbits;
> -		if (addr > INT_MAX)
> -			WARN(1, "would truncate bmap result\n");

Frankly I would've combined these two patches to make it more obvious
that we're hoisting a FIBMAP constraint check from iomap into the ioctl
handler.

--D

> -		else
> -			*bno = addr;
> +		*bno = addr;
>  	}
>  	return 0;
>  }
> -- 
> 2.21.0
>