JFFS2: fix unmount regression

This patch fixes regression introduced by
"8bdc81c jffs2: get rid of jffs2_sync_super". We submit a delayed work in order
to make sure the write-buffer is synchronized at some point. But we do not
flush it when we unmount, which causes an oops when we unmount the file-system
and then the delayed work is executed.

This patch fixes the issue by adding a "cancel_delayed_work_sync()" infocation
in the '->sync_fs()' handler. This will make sure the delayed work is canceled
on sync, unmount and re-mount. And because VFS always callse 'sync_fs()' before
unmounting or remounting, this fixes the issue.

Reported-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org [3.5+]
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 61ea413..1224d6b 100644 (file)
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -100,6 +100,10 @@ static int jffs2_sync_fs(struct super_block *sb, int wait)
 {
        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 
+#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
+       cancel_delayed_work_sync(&c->wbuf_dwork);
+#endif
+
        mutex_lock(&c->alloc_sem);
        jffs2_flush_wbuf_pad(c);
        mutex_unlock(&c->alloc_sem);