Re: [PATCH 1/3] xfs: Use __xfs_buf_submit everywhere

[Nikolay Borisov <nborisov@suse.com>]

On 13.08.19 г. 14:55 ч., Brian Foster wrote:
> On Tue, Aug 13, 2019 at 12:03:04PM +0300, Nikolay Borisov wrote:
>> Currently xfs_buf_submit is used as a tiny wrapper to __xfs_buf_submit.
>> It only checks whether XFB_ASYNC flag is set and sets the second
>> parameter to __xfs_buf_submit accordingly. It's possible to remove the
>> level of indirection since in all contexts where xfs_buf_submit is
>> called we already know if XBF_ASYNC is set or not.
>>
>> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
>> ---
> 
> Random nit: the use of upper case in the first word of the commit log
> subject line kind of stands out to me. I know there are other instances
> of this (I think I noticed one the other day), but my presumption was
> that it was random/accidental where your patches seem to do it
> intentionally. Do we have a common practice here? Do we care? I prefer
> consistency of using lower case for normal text, but it's really just a
> nit.

I consider the commit log subject and commit log body to be 2 separate
paragraphs, hence I start each one with capital letter.

> 
>>  fs/xfs/xfs_buf.c         | 8 +++++---
>>  fs/xfs/xfs_buf_item.c    | 2 +-
>>  fs/xfs/xfs_log_recover.c | 2 +-
>>  3 files changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
>> index ca0849043f54..a75d05e49a98 100644
>> --- a/fs/xfs/xfs_buf.c
>> +++ b/fs/xfs/xfs_buf.c
>> @@ -751,13 +751,15 @@ _xfs_buf_read(
>>  	xfs_buf_t		*bp,
>>  	xfs_buf_flags_t		flags)
>>  {
>> +	bool wait = bp->b_flags & XBF_ASYNC ? false : true;
>> +
> 
> This doesn't look quite right. Just below we clear several flags from
> ->b_flags then potentially reapply based on the flags parameter. Hence,
> I think ->b_flags above may not reflect ->b_flags by the time we call
> __xfs_buf_submit().

It's correct the flag clearing/setting ensures that the only flags we
have in bp->b_flags are in the set: flags & (XBF_READ | XBF_ASYNC |
XBF_READ_AHEAD);

So if XBF_ASYNC was set initially it will also be set when we call
xfs_buf_submit.


> 
> Brian
> 
>>  	ASSERT(!(flags & XBF_WRITE));
>>  	ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL);
>>  
>>  	bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
>>  	bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
>>  
>> -	return xfs_buf_submit(bp);
>> +	return __xfs_buf_submit(bp, wait);
>>  }
>>  
>>  /*
>> @@ -883,7 +885,7 @@ xfs_buf_read_uncached(
>>  	bp->b_flags |= XBF_READ;
>>  	bp->b_ops = ops;
>>  
>> -	xfs_buf_submit(bp);
>> +	__xfs_buf_submit(bp, true);
>>  	if (bp->b_error) {
>>  		int	error = bp->b_error;
>>  		xfs_buf_relse(bp);
>> @@ -1214,7 +1216,7 @@ xfs_bwrite(
>>  	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
>>  			 XBF_WRITE_FAIL | XBF_DONE);
>>  
>> -	error = xfs_buf_submit(bp);
>> +	error = __xfs_buf_submit(bp, true);
>>  	if (error)
>>  		xfs_force_shutdown(bp->b_mount, SHUTDOWN_META_IO_ERROR);
>>  	return error;
>> diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
>> index 7dcaec54a20b..fef08980dd21 100644
>> --- a/fs/xfs/xfs_buf_item.c
>> +++ b/fs/xfs/xfs_buf_item.c
>> @@ -1123,7 +1123,7 @@ xfs_buf_iodone_callback_error(
>>  			bp->b_first_retry_time = jiffies;
>>  
>>  		xfs_buf_ioerror(bp, 0);
>> -		xfs_buf_submit(bp);
>> +		__xfs_buf_submit(bp, false);
>>  		return true;
>>  	}
>>  
>> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
>> index 13d1d3e95b88..64e315f80147 100644
>> --- a/fs/xfs/xfs_log_recover.c
>> +++ b/fs/xfs/xfs_log_recover.c
>> @@ -5610,7 +5610,7 @@ xlog_do_recover(
>>  	bp->b_flags |= XBF_READ;
>>  	bp->b_ops = &xfs_sb_buf_ops;
>>  
>> -	error = xfs_buf_submit(bp);
>> +	error = __xfs_buf_submit(bp, true);
>>  	if (error) {
>>  		if (!XFS_FORCED_SHUTDOWN(mp)) {
>>  			xfs_buf_ioerror_alert(bp, __func__);
>> -- 
>> 2.17.1
>>
>