backport jffs2 eofdetect patch to linux 2.4

git-svn-id: svn://svn.openwrt.org/openwrt/branches/buildroot-ng/openwrt@4044 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 87 insertions, 0 deletions

diff --git a/target/linux/generic-2.4/patches/227-jffs2_eofdetect.patch b/target/linux/generic-2.4/patches/227-jffs2_eofdetect.patch
new file mode 100644
index 000000000..6288bd575
--- /dev/null
+++ b/target/linux/generic-2.4/patches/227-jffs2_eofdetect.patch
@@ -0,0 +1,87 @@
+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;
+