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Subject: Re: [PATCH 2/2] iomap: bmap: Remove the WARN and return the proper
 block address
To:     "Darrick J. Wong" <darrick.wong@oracle.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Jan Kara <jack@suse.com>, tytso@mit.edu,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        linux-ext4@vger.kernel.org
References: <cover.1587670914.git.riteshh@linux.ibm.com>
 <e2e09c5d840458b4ace6f9b31429ceefd9c1df01.1587670914.git.riteshh@linux.ibm.com>
 <20200424174815.GF6733@magnolia>
From:   Ritesh Harjani <riteshh@linux.ibm.com>
Date:   Sat, 25 Apr 2020 04:09:14 +0530
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On 4/24/20 11:18 PM, Darrick J. Wong wrote:
> 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.

Sure, let me combine the two in v2.

Thanks!!
-ritesh

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