From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Dongyang Li <dongyangli@ddn.com>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"adilger@dilger.ca" <adilger@dilger.ca>
Subject: Re: [PATCH 1/2] libext2fs: optimize ext2fs_convert_subcluster_bitmap()
Date: Mon, 19 Aug 2019 00:39:25 -0400 [thread overview]
Message-ID: <20190819043925.GC10349@mit.edu> (raw)
In-Reply-To: <20190816034834.29439-1-dongyangli@ddn.com>
On Fri, Aug 16, 2019 at 03:49:12AM +0000, Dongyang Li wrote:
> @@ -28,6 +28,7 @@
> #ifdef HAVE_SYS_TIME_H
> #include <sys/time.h>
> #endif
> +#include <sys/param.h>
>
> #include "ext2_fs.h"
> #include "ext2fsP.h"
Please don't don't depend on <sys/param.h> for definitions of macros
like roundup(). It's not going to be present on all OS's, and
e2fsprogs needs to be portable to more systems than just Linux.
Furthermore, if you look in ext2fs.h, we already have the macros:
#define EXT2FS_B2C(fs, blk) ((blk) >> (fs)->cluster_ratio_bits)
#define EXT2FS_C2B(fs, cluster) ((cluster) << (fs)->cluster_ratio_bits)
... which translates a block to a cluster number and vice versa.
(Note that the cluster:block ratio is always a power of two.)
So instead of this:
> + i = bmap->start + roundup(next - bmap->start + 1, ratio);
you can do this:
i = EXT2FS_C2B(fs, EXT2FS_B2C(fs, next) + 1);
cheers,
- Ted
prev parent reply other threads:[~2019-08-19 4:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-16 3:49 [PATCH 1/2] libext2fs: optimize ext2fs_convert_subcluster_bitmap() Dongyang Li
2019-08-16 3:49 ` [PATCH 2/2] mke2fs: set overhead in super block for bigalloc Dongyang Li
2019-08-16 7:01 ` Andreas Dilger
2019-08-19 5:09 ` Theodore Y. Ts'o
2019-08-16 5:58 ` [PATCH 1/2] libext2fs: optimize ext2fs_convert_subcluster_bitmap() Andreas Dilger
2019-08-19 4:39 ` Theodore Y. Ts'o [this message]
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