[GFS2] Fix lock ordering bug in page fault path

Mmapped files were able to trigger a lock ordering bug. Private
maps do not need to take the glock so early on. Shared maps do
unfortunately, however we can get around that by adding a flag
into the flags for the struct gfs2_file. This only works because
we are taking an exclusive lock at this point, so we know that
nobody else can be racing with us.

Fixes Red Hat bugzilla: #201196

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 60fdc94ccc8a..a591fb8fae20 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -256,8 +256,8 @@ static unsigned int current_tail(struct gfs2_sbd *sdp)
         if (list_empty(&sdp->sd_ail1_list))
                 tail = sdp->sd_log_head;
         else {
-                ai = list_entry(sdp->sd_ail1_list.prev,
-                                struct gfs2_ail, ai_list);
+                ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail,
+                                ai_list);
                 tail = ai->ai_first;
         }