From e631ddba588783edd521c5a89f7b2902772fb691 Mon Sep 17 00:00:00 2001 From: Ferenc Havasi Date: Wed, 7 Sep 2005 09:35:26 +0100 Subject: [JFFS2] Add erase block summary support (mount time improvement) The goal of summary is to speed up the mount time. Erase block summary (EBS) stores summary information at the end of every (closed) erase block. It is no longer necessary to scan all nodes separetly (and read all pages of them) just read this "small" summary, where every information is stored which is needed at mount time. This summary information is stored in a JFFS2_FEATURE_RWCOMPAT_DELETE. During the mount process if there is no summary info the orignal scan process will be executed. EBS works with NAND and NOR flashes, too. There is a user space tool called sumtool to generate this summary information for a JFFS2 image. Signed-off-by: Ferenc Havasi Signed-off-by: Thomas Gleixner --- include/linux/jffs2.h | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'include/linux/jffs2.h') diff --git a/include/linux/jffs2.h b/include/linux/jffs2.h index a66d0a8b70e4..acb51a3669a2 100644 --- a/include/linux/jffs2.h +++ b/include/linux/jffs2.h @@ -8,7 +8,7 @@ * For licensing information, see the file 'LICENCE' in the * jffs2 directory. * - * $Id: jffs2.h,v 1.36 2005/07/26 13:19:36 havasi Exp $ + * $Id: jffs2.h,v 1.37 2005/09/07 08:34:55 havasi Exp $ * */ @@ -28,6 +28,9 @@ #define JFFS2_EMPTY_BITMASK 0xffff #define JFFS2_DIRTY_BITMASK 0x0000 +/* Summary node MAGIC marker */ +#define JFFS2_SUM_MAGIC 0x02851885 + /* We only allow a single char for length, and 0xFF is empty flash so we don't want it confused with a real length. Hence max 254. */ @@ -60,6 +63,8 @@ #define JFFS2_NODETYPE_CLEANMARKER (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 3) #define JFFS2_NODETYPE_PADDING (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 4) +#define JFFS2_NODETYPE_SUMMARY (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 6) + // Maybe later... //#define JFFS2_NODETYPE_CHECKPOINT (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 3) //#define JFFS2_NODETYPE_OPTIONS (JFFS2_FEATURE_RWCOMPAT_COPY | JFFS2_NODE_ACCURATE | 4) @@ -146,10 +151,24 @@ struct jffs2_raw_inode uint8_t data[0]; } __attribute__((packed)); +struct jffs2_summary_node{ + jint16_t magic; + jint16_t nodetype; /* = JFFS2_NODETYPE_INODE_SUM */ + jint32_t totlen; + jint32_t hdr_crc; + jint32_t sum_num; /* number of sum entries*/ + jint32_t cln_mkr; /* clean marker size, 0 = no cleanmarker */ + jint32_t padded; /* sum of the size of padding nodes */ + jint32_t sum_crc; /* summary information crc */ + jint32_t node_crc; /* node crc */ + jint32_t sum[0]; /* inode summary info */ +} __attribute__((packed)); + union jffs2_node_union { struct jffs2_raw_inode i; struct jffs2_raw_dirent d; struct jffs2_unknown_node u; + struct jffs2_summary_node s; }; #endif /* __LINUX_JFFS2_H__ */ -- cgit v1.2.3