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Subject: Re: [RFCv3 2/4] ext4: Add ext4_ilock & ext4_iunlock API
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Matthew Bobrowski <mbobrowski@mbobrowski.org>, jack@suse.cz,
        tytso@mit.edu, linux-ext4@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
References: <20191120050024.11161-1-riteshh@linux.ibm.com>
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 <20191120112339.GB30486@bobrowski>
 <20191120121831.9639B42047@d06av24.portsmouth.uk.ibm.com>
 <20191120163500.GT20752@bombadil.infradead.org>
From:   Ritesh Harjani <riteshh@linux.ibm.com>
Date:   Sat, 23 Nov 2019 17:21:46 +0530
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On 11/20/19 10:05 PM, Matthew Wilcox wrote:
> On Wed, Nov 20, 2019 at 05:48:30PM +0530, Ritesh Harjani wrote:
>> Not against your suggestion here.
>> But in kernel I do see a preference towards object followed by a verb.
>> At least in vfs I see functions like inode_lock()/unlock().
>>
>> Plus I would not deny that this naming is also inspired from
>> xfs_ilock()/iunlock API names.
> 
> I see those names as being "classical Unix" heritage (eh, maybe SysV).
> 
>> hmm, it was increasing the name of the macro if I do it that way.
>> But that's ok. Is below macro name better?
>>
>> #define EXT4_INODE_IOLOCK_EXCL		(1 << 0)
>> #define EXT4_INODE_IOLOCK_SHARED	(1 << 1)
> 
> In particular, Linux tends to prefer read/write instead of
> shared/exclusive terminology.  rwlocks, rwsems, rcu_read_lock, seqlocks.
> shared/exclusive is used by file locks.  And XFS ;-)
> 
> I agree with Jan; just leave them opencoded.

Sure.

> 
> Probably worth adding inode_lock_downgrade() to fs.h instead of
> accessing i_rwsem directly.
> 

Yup, make sense. but since this series is independent of that change,
let me add that as a separate patch after this series.


Thanks for the review!!
-ritesh