Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756574Ab2JERqZ (ORCPT ); Fri, 5 Oct 2012 13:46:25 -0400 Received: from mondschein.lichtvoll.de ([194.150.191.11]:52592 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754229Ab2JERqX convert rfc822-to-8bit (ORCPT ); Fri, 5 Oct 2012 13:46:23 -0400 From: Martin Steigerwald To: linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/16] f2fs: add on-disk layout Date: Fri, 5 Oct 2012 19:46:21 +0200 User-Agent: KMail/1.13.7 (Linux/3.6.0-tp520; KDE/4.8.4; x86_64; ; ) Cc: =?utf-8?q?=EA=B9=80=EC=9E=AC=EA=B7=B9?= , viro@zeniv.linux.org.uk, "'Theodore Ts'o'" , gregkh@linuxfoundation.org, chur.lee@samsung.com, cm224.lee@samsung.com, jooyoung.hwang@samsung.com References: <000901cda2f0$7d773eb0$7865bc10$%kim@samsung.com> (sfid-20121005_184512_086765_45BFD6B3) In-Reply-To: <000901cda2f0$7d773eb0$7865bc10$%kim@samsung.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Message-Id: <201210051946.21451.Martin@lichtvoll.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3859 Lines: 81 Am Freitag, 5. Oktober 2012 schrieb 김재극: > This adds a header file describing the on-disk layout of f2fs. > > Signed-off-by: Changman Lee > Signed-off-by: Chul Lee > Signed-off-by: Jaegeuk Kim > --- > include/linux/f2fs_fs.h | 359 +++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 359 insertions(+) > create mode 100644 include/linux/f2fs_fs.h > > diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h > new file mode 100644 > index 0000000..b17eeec > --- /dev/null > +++ b/include/linux/f2fs_fs.h > @@ -0,0 +1,359 @@ > +/** > + * include/linux/f2fs_fs.h […] > +/* > + * For superblock > + */ > +struct f2fs_super_block { > + __le32 magic; /* Magic Number */ > + __le16 major_ver; /* Major Version */ > + __le16 minor_ver; /* Minor Version */ > + __le32 log_sectorsize; /* log2 (Sector size in bytes) */ > + __le32 log_sectors_per_block; /* log2 (Number of sectors per block */ > + __le32 log_blocksize; /* log2 (Block size in bytes) */ > + __le32 log_blocks_per_seg; /* log2 (Number of blocks per segment) */ > + __le32 log_segs_per_sec; /* log2 (Number of segments per section) */ > + __le32 secs_per_zone; /* Number of sections per zone */ > + __le32 checksum_offset; /* Checksum position in this super block */ > + __le64 block_count; /* Total number of blocks */ > + __le32 section_count; /* Total number of sections */ > + __le32 segment_count; /* Total number of segments */ > + __le32 segment_count_ckpt; /* Total number of segments > + in Checkpoint area */ > + __le32 segment_count_sit; /* Total number of segments > + in Segment information table */ > + __le32 segment_count_nat; /* Total number of segments > + in Node address table */ > + /*Total number of segments in Segment summary area */ > + __le32 segment_count_ssa; > + /* Total number of segments in Main area */ > + __le32 segment_count_main; > + __le32 failure_safe_block_distance; > + __le64 segment0_blkaddr; /* Start block address of Segment 0 */ > + __le64 start_segment_checkpoint; /* Start block address of ckpt */ > + __le64 sit_blkaddr; /* Start block address of SIT */ > + __le64 nat_blkaddr; /* Start block address of NAT */ > + __le64 ssa_blkaddr; /* Start block address of SSA */ > + __le64 main_blkaddr; /* Start block address of Main area */ > + __le32 root_ino; /* Root directory inode number */ > + __le32 node_ino; /* node inode number */ > + __le32 meta_ino; /* meta inode number */ > + __le32 volume_serial_number; /* VSN is optional field */ > + __le16 volume_name[8]; /* Volume Name. 8 unicode characters */ > +} __packed; Any reason why volume label is that short? If superblock can occupy up to 4096 bytes, i.e. a block, I think a bit more space for volume label would fit in there. I count 128 bytes up to volume_name. Do other structures need to fit in superblock as well? I believe users easily can hit a limit of 8 unicode characters even for USB sticks and SD cards. Nice to see a flash friendly filesystem which seems to take lots of the stuff in account I read at Linaro website about flash devices. -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/