From eb9181b33bdda2e1ce81094d77913f7b68e26156 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sun, 22 Mar 2015 15:59:33 +0100
Subject: [PATCH] mount_root: keep track of overlay initialization state (via
 xattr)

Remove all files (except sysupgrade.tgz) if /etc/init.d/done was not called

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 jffs2reset.c            |  1 +
 libfstools/libfstools.h | 10 +++++++
 libfstools/overlay.c    | 58 ++++++++++++++++++++++++++++++++++++++++-
 mount_root.c            |  5 ++++
 4 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/jffs2reset.c b/jffs2reset.c
index c9d4f5f..1080883 100644
--- a/jffs2reset.c
+++ b/jffs2reset.c
@@ -62,6 +62,7 @@ jffs2_reset(int argc, char **argv)
 	mp = find_mount_point(v->blk, 1);
 	if (mp) {
 		ULOG_INFO("%s is mounted as %s, only erasing files\n", v->blk, mp);
+		fs_state_set("/overlay", FS_STATE_PENDING);
 		overlay_delete(mp, false);
 		mount(mp, "/", NULL, MS_REMOUNT, 0);
 	} else {
diff --git a/libfstools/libfstools.h b/libfstools/libfstools.h
index 1d41eea..31d9f9e 100644
--- a/libfstools/libfstools.h
+++ b/libfstools/libfstools.h
@@ -28,6 +28,13 @@ enum {
 	FS_UBIFS,
 };
 
+enum fs_state {
+	FS_STATE_UNKNOWN,
+	FS_STATE_PENDING,
+	FS_STATE_READY,
+	__FS_STATE_LAST = FS_STATE_READY,
+};
+
 extern char const *extroot_prefix;
 extern int mount_extroot(void);
 extern int mount_snapshot(struct volume *v);
@@ -50,4 +57,7 @@ extern void foreachdir(const char *dir, int (*cb)(const char*));
 
 extern void overlay_delete(const char *dir, bool keep_sysupgrade);
 
+enum fs_state fs_state_get(const char *dir);
+int fs_state_set(const char *dir, enum fs_state state);
+
 #endif
diff --git a/libfstools/overlay.c b/libfstools/overlay.c
index 7c9b480..3269a52 100644
--- a/libfstools/overlay.c
+++ b/libfstools/overlay.c
@@ -14,6 +14,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/mount.h>
+#include <sys/syscall.h>
 
 #include <asm/byteorder.h>
 
@@ -34,6 +35,18 @@
 
 static bool keep_sysupgrade;
 
+static ssize_t
+fs_getxattr(const char *path, const char *name, void *value, size_t size)
+{
+	return syscall(__NR_getxattr, path, name, value, size);
+}
+
+static ssize_t
+fs_setxattr(const char *path, const char *name, const void *value, size_t size, int flags)
+{
+	return syscall(__NR_setxattr, path, name, value, size, flags);
+}
+
 static int
 handle_rmdir(const char *dir)
 {
@@ -235,7 +248,13 @@ jffs2_switch(struct volume *v)
 		}
 		break;
 	}
-	return ret;
+
+	if (ret)
+		return ret;
+
+	sync();
+	fs_state_set("/overlay", FS_STATE_READY);
+	return 0;
 }
 
 static int overlay_mount_fs(struct volume *v)
@@ -266,6 +285,28 @@ static int overlay_mount_fs(struct volume *v)
 	return -1;
 }
 
+enum fs_state fs_state_get(const char *dir)
+{
+	uint32_t val;
+
+	if (fs_getxattr(dir, "user.fs_state", &val, sizeof(val)) != sizeof(val))
+		return FS_STATE_UNKNOWN;
+
+	if (val > __FS_STATE_LAST)
+		return FS_STATE_UNKNOWN;
+
+	return val;
+}
+
+
+int fs_state_set(const char *dir, enum fs_state state)
+{
+	uint32_t val = state;
+
+	return fs_setxattr(dir, "user.fs_state", &val, sizeof(val), 0);
+}
+
+
 int mount_overlay(struct volume *v)
 {
 	char *mp;
@@ -287,6 +328,21 @@ int mount_overlay(struct volume *v)
 		return 0;
 	}
 
+	switch(fs_state_get("/tmp/overlay")) {
+	case FS_STATE_UNKNOWN:
+		fs_state_set("/tmp/overlay", FS_STATE_PENDING);
+		if (fs_state_get("/tmp/overlay") != FS_STATE_PENDING) {
+			ULOG_ERR("unable to set filesystem state\n");
+			break;
+		}
+	case FS_STATE_PENDING:
+		ULOG_INFO("overlay filesystem has not been fully initialized yet\n");
+		overlay_delete("/tmp/overlay", true);
+		break;
+	case FS_STATE_READY:
+		break;
+	}
+
 	ULOG_INFO("switching to jffs2 overlay\n");
 	if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
 		ULOG_ERR("switching to jffs2 failed - fallback to ramoverlay\n");
diff --git a/mount_root.c b/mount_root.c
index bfbe217..7b69c7f 100644
--- a/mount_root.c
+++ b/mount_root.c
@@ -103,6 +103,11 @@ done(int argc, char *argv[1])
 	case FS_NONE:
 	case FS_DEADCODE:
 		return jffs2_switch(v);
+
+	case FS_JFFS2:
+	case FS_UBIFS:
+		fs_state_set("/overlay", FS_STATE_READY);
+		break;
 	}
 
 	return 0;
-- 
2.25.1