From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryusuke Konishi Subject: Re: [RFC][PATCH] nilfs2: enlarge s_volume_name member Date: Sun, 02 May 2010 11:59:38 +0900 (JST) Message-ID: <20100502.115938.01479064.ryusuke@osrg.net> References: <878w834pml.wl%jir@sekiba.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <878w834pml.wl%jir-27yqGEOhnJbQT0dZR+AlfA@public.gmane.org> Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org Cc: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, konishi.ryusuke-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org Hi, On Sun, 02 May 2010 00:18:26 +0900, Jiro SEKIBA wrote: > Hi, > > This is an RFC patch to enlarge s_volume_name member of nilfs_super_block. > > Current s_volume_name has 16 bytes, which is too small as modern filesystem. > > s_last_mounted resides just after s_volume_name and has 64 bytes. > > s_last_mounted is historically came from ext2, but not used in nilfs2 at all. > Deleting s_last_mounted member and merging that space with s_volume_name > enlarge s_volume_name upto 80 bytes for volume label. > > When user land tools see the old header for new disk, it will just ignore > additional bytes stored in s_last_mounted. While, old disk format has only > 16 bytes label, it doesn't affects in case seeing the new header for old disk. > > Signed-off-by: Jiro SEKIBA Thank you for the proposal. You're right. The current s_volume_name/s_last_mounted are mimics of ext2/ext3, and looking back today, the 16 bytes volume name looks a bit short. Appending the region reserved for s_last_mounted to s_volume_name is quite a nice idea! I confirmed that this simple patch doesn't sacrifice compatibility. This should be incorporated while we can. BTW, the patch hit a style issue that I recently fixed with the patch titled "nilfs2: fix style problems in nilfs2_fs.h": $ scripts/checkpatch.pl --file include/linux/nilfs2_fs.h WARNING: please, no space before tabs #210: FILE: linux/nilfs2_fs.h:210: +^Ichar^Is_volume_name[80]; ^I/* volume name */$ Could you rewrite it for the for-next branch of nilfs2.git? You can also remove ``RFC'' from the changelog next time. Thank you in advance, Ryusuke Konishi > --- > include/linux/nilfs2_fs.h | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) > > diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h > index 640702e..a41931d 100644 > --- a/include/linux/nilfs2_fs.h > +++ b/include/linux/nilfs2_fs.h > @@ -207,8 +207,7 @@ struct nilfs_super_block { > __le16 s_segment_usage_size; /* Size of a segment usage */ > > __u8 s_uuid[16]; /* 128-bit uuid for volume */ > - char s_volume_name[16]; /* volume name */ > - char s_last_mounted[64]; /* directory where last mounted */ > + char s_volume_name[80]; /* volume name */ > > __le32 s_c_interval; /* Commit interval of segment */ > __le32 s_c_block_max; /* Threshold of data amount for > -- > 1.5.6.5 > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html