[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, 3 insertions, 6 deletions

diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 7aabc03e4abd..bbd44a4b1a1f 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -153,8 +153,7 @@ static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
 
         if (lh.lh_header.mh_magic != GFS2_MAGIC ||
             lh.lh_header.mh_type != GFS2_METATYPE_LH ||
-            lh.lh_blkno != blk ||
-            lh.lh_hash != hash)
+            lh.lh_blkno != blk || lh.lh_hash != hash)
                 return 1;
 
         *head = lh;
@@ -482,11 +481,9 @@ int gfs2_recover_journal(struct gfs2_jdesc *jd)
 
                 /* Acquire a shared hold on the transaction lock */
 
-                error = gfs2_glock_nq_init(sdp->sd_trans_gl,
-                                           LM_ST_SHARED,
+                error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED,
                                            LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
-                                           GL_NOCANCEL | GL_NOCACHE,
-                                           &t_gh);
+                                           GL_NOCANCEL | GL_NOCACHE, &t_gh);
                 if (error)
                         goto fail_gunlock_ji;