From: "Dilger, Andreas" <andreas.dilger@intel.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] ext4: return non-zero st_blocks for inline data
Date: Fri, 8 Nov 2013 12:25:30 +0000 [thread overview]
Message-ID: <CEA2256B.7F605%andreas.dilger@intel.com> (raw)
In-Reply-To: <20131108034504.GC11668@thunk.org>
On 2013/11/07 8:45 PM, "Theodore Ts'o" <tytso@mit.edu> wrote:
>On Wed, Nov 06, 2013 at 03:42:32AM -0700, Andreas Dilger wrote:
>> @@ -4542,9 +4551,9 @@ int ext4_getattr(struct vfsmount *mnt, struct
>>dentry *dentry,
>> * blocks for this file.
>> */
>> delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
>> - EXT4_I(inode)->i_reserved_data_blocks);
>> + EXT4_I(inode)->i_reserved_data_blocks);
>> + stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits -
>>9);
>>
>> - stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
>
>Why this change to the calculation to stat->blocks?
Just code cleanup. The lack of spaces around ">>9" irked me.
The calculation is the same (s_blocksize_bits can never be less than 10
for ext* filesystems), but avoids doing two separate shifts that the
compiler cannot optimize together due to parenthesis and potential side
effects (e.g. this kind of operation could be used to mask off the top
bits, but isn't doing so here).
Cheers, Andreas
--
Andreas Dilger
Lustre Software Architect
Intel High Performance Data Division
next prev parent reply other threads:[~2013-11-08 12:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-06 10:42 [PATCH] ext4: return non-zero st_blocks for inline data Andreas Dilger
2013-11-08 3:45 ` Theodore Ts'o
2013-11-08 12:25 ` Dilger, Andreas [this message]
2013-11-12 3:44 ` Theodore Ts'o
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