Leave superblocks on s_list until the end

We used to remove from s_list and s_instances at the same
time.  So let's *not* do the former and skip superblocks
that have empty s_instances in the loops over s_list.

The next step, of course, will be to get rid of rescan logics
in those loops.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/sync.c b/fs/sync.c
index 92b228176f7c..ad6691bae370 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -99,10 +99,13 @@ static void sync_filesystems(int wait)
         mutex_lock(&mutex);             /* Could be down_interruptible */
         spin_lock(&sb_lock);
         list_for_each_entry(sb, &super_blocks, s_list)
-                sb->s_need_sync = 1;
+                if (!list_empty(&sb->s_instances))
+                        sb->s_need_sync = 1;
 
 restart:
         list_for_each_entry(sb, &super_blocks, s_list) {
+                if (list_empty(&sb->s_instances))
+                        continue;
                 if (!sb->s_need_sync)
                         continue;
                 sb->s_need_sync = 0;