openwrt-xburst/target/linux/generic-2.4/patches/227-jffs2_eofdetect.patch

diff -ur linux.old/fs/jffs2/scan.c linux.dev/fs/jffs2/scan.c
--- linux.old/fs/jffs2/scan.c	2003-11-28 19:26:21.000000000 +0100
+++ linux.dev/fs/jffs2/scan.c	2006-06-22 00:29:02.000000000 +0200
@@ -31,6 +31,10 @@
  * provisions above, a recipient may use your version of this file
  * under either the RHEPL or the GPL.
  *
+ * Modification for automatically cleaning the filesystem after
+ * a specially marked block
+ * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
+ *
  * $Id: scan.c,v 1.51.2.4 2003/11/02 13:51:18 dwmw2 Exp $
  *
  */
@@ -88,7 +92,12 @@
 	for (i=0; i<c->nr_blocks; i++) {
 		struct jffs2_eraseblock *jeb = &c->blocks[i];
 
-		ret = jffs2_scan_eraseblock(c, jeb);
+
+		if (c->flags & (1 << 7))
+			ret = 1;
+		else
+			ret = jffs2_scan_eraseblock(c, jeb);
+
 		if (ret < 0)
 			return ret;
 
@@ -145,15 +154,22 @@
 			c->nr_erasing_blocks++;
 		}
 	}
-	/* Rotate the lists by some number to ensure wear levelling */
-	jffs2_rotate_lists(c);
 
-	if (c->nr_erasing_blocks) {
-		if (!c->used_size && empty_blocks != c->nr_blocks) {
-			printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
-			return -EIO;
+	if (c->flags & (1 << 7)) {
+		printk("jffs2_scan_medium(): erasing all blocks after the end marker...\n");
+		jffs2_erase_pending_blocks(c);
+		printk("jffs2_scan_medium(): done.\n");
+	} else {
+		/* Rotate the lists by some number to ensure wear levelling */
+		jffs2_rotate_lists(c);
+
+		if (c->nr_erasing_blocks) {
+			if (!c->used_size && empty_blocks != c->nr_blocks) {
+				printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
+				return -EIO;
+			}
+			jffs2_erase_pending_trigger(c);
 		}
-		jffs2_erase_pending_trigger(c);
 	}
 	return 0;
 }
@@ -181,6 +197,7 @@
 
 	while(ofs < jeb->offset + c->sector_size) {
 		ssize_t retlen;
+		unsigned char *buf = (unsigned char *) &node;
 		ACCT_PARANOIA_CHECK(jeb);
 		
 		if (ofs & 3) {
@@ -202,8 +219,18 @@
 			break;
 		}
 
-		err = c->mtd->read(c->mtd, ofs, sizeof(node), &retlen, (char *)&node);
+		err = c->mtd->read(c->mtd, ofs, sizeof(node), &retlen, buf);
+		if ((buf[0] == 0xde) &&
+			(buf[1] == 0xad) &&
+			(buf[2] == 0xc0) &&
+			(buf[3] == 0xde)) {
+				
+			/* end of filesystem. erase everything after this point */
+			c->flags |= (1 << 7);
+			printk("jffs2_scan_eraseblock(): End of filesystem marker found at 0x%x\n", jeb->offset);
 		
+			return 1;
+		}
 		if (err) {
 			D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", sizeof(node), ofs, err));
 			return err;