Re: [PATCH v3 3/9] xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset

From: Zhang Yi <yi.zhang@huaweicloud.com>
To: "Darrick J. Wong" <djwong@kernel.org>, hch@infradead.org
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, brauner@kernel.org,
	david@fromorbit.com, tytso@mit.edu, jack@suse.cz,
	yi.zhang@huawei.com, chengzhihao1@huawei.com, yukuai3@huawei.com
Subject: Re: [PATCH v3 3/9] xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset
Date: Wed, 20 Mar 2024 09:51:26 +0800	[thread overview]
Message-ID: <054ac072-4ccf-b83c-cc9c-cbb5d6f5dbdb@huaweicloud.com> (raw)
In-Reply-To: <20240319204552.GG1927156@frogsfrogsfrogs>

On 2024/3/20 4:45, Darrick J. Wong wrote:
> On Tue, Mar 19, 2024 at 09:10:56AM +0800, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> Since xfs_bmapi_convert_delalloc() only attempts to allocate the entire
>> delalloc extent and require multiple invocations to allocate the target
>> offset. So xfs_convert_blocks() add a loop to do this job and we call it
>> in the write back path, but xfs_convert_blocks() isn't a common helper.
>> Let's do it in xfs_bmapi_convert_delalloc() and drop
>> xfs_convert_blocks(), preparing for the post EOF delalloc blocks
>> converting in the buffered write begin path.
>>
>> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>>  fs/xfs/libxfs/xfs_bmap.c | 34 +++++++++++++++++++++++--
>>  fs/xfs/xfs_aops.c        | 54 +++++++++++-----------------------------
>>  2 files changed, 46 insertions(+), 42 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
>> index 07dc35de8ce5..042e8d3ab0ba 100644
>> --- a/fs/xfs/libxfs/xfs_bmap.c
>> +++ b/fs/xfs/libxfs/xfs_bmap.c
>> @@ -4516,8 +4516,8 @@ xfs_bmapi_write(
>>   * invocations to allocate the target offset if a large enough physical extent
>>   * is not available.
>>   */
>> -int
>> -xfs_bmapi_convert_delalloc(
>> +static int
> 
> static inline?
> 

I'd suggest to leave that to the compiler too.

>> +__xfs_bmapi_convert_delalloc(
> 
> Double underscore prefixes read to me like "do this without grabbing
> a lock or a resource", not just one step in a loop.
> 
> Would you mind changing it to xfs_bmapi_convert_one_delalloc() ?
> Then the callsite looks like:
> 
> xfs_bmapi_convert_delalloc(...)
> {
> 	...
> 	do {
> 		error = xfs_bmapi_convert_one_delalloc(ip, whichfork, offset,
> 					iomap, seq);
> 		if (error)
> 			return error;
> 	} while (iomap->offset + iomap->length <= offset);
> }
> 

Thanks for your suggestions, all subsequent improvements in this series are
also looks fine by me, I will revise them in my next iteration. Christoph,
I will keep your review tag, please let me know if you have different
opinion.

Thanks,
Yi.