[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 <havasi@inf.u-szeged.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 32 insertions, 2 deletions

diff --git a/fs/jffs2/writev.c b/fs/jffs2/writev.c
index f079f8388566..6d8c27c5e723 100644
--- a/fs/jffs2/writev.c
+++ b/fs/jffs2/writev.c
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: writev.c,v 1.6 2004/11/16 20:36:12 dwmw2 Exp $
+ * $Id: writev.c,v 1.7 2005/09/07 08:34:55 havasi Exp $
  *
  */
 
@@ -44,7 +44,37 @@ int jffs2_flash_direct_writev(struct jffs2_sb_info *c, const struct kvec *vecs,
 {
         if (c->mtd->writev)
                 return c->mtd->writev(c->mtd, vecs, count, to, retlen);
-        else
+        else {
+                if (jffs2_sum_active()) {
+                        int res;
+
+                        res = jffs2_sum_add_kvec(c, vecs, count, (uint32_t) to);
+                        if (res) {
+                                return res;
+                        }
+                }
+
                 return mtd_fake_writev(c->mtd, vecs, count, to, retlen);
+        }
 }
 
+int jffs2_flash_direct_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
+                        size_t *retlen, const u_char *buf)
+{
+        int ret;
+        ret = c->mtd->write(c->mtd, ofs, len, retlen, buf);
+
+        if (jffs2_sum_active()) {
+                struct kvec vecs[1];
+                int res;
+
+                vecs[0].iov_base = (unsigned char *) buf;
+                vecs[0].iov_len = len;
+
+                res = jffs2_sum_add_kvec(c, vecs, 1, (uint32_t) ofs);
+                if (res) {
+                        return res;
+                }
+        }
+        return ret;
+}