GFS2: Allow glocks to be unlocked after withdraw

This bug fixes a regression introduced by patch 733479a925.

The intent of the patch was to stop promoting glocks after a
file system is withdrawn due to a variety of errors, because doing
so results in a BUG(). (You should be able to unmount after a
withdraw rather than having the kernel panic.)

Unfortunately, it also stopped demotions, so glocks could not be
unlocked after withdraw, which means the unmount would hang.

This patch allows function do_xmote to demote locks to an
unlocked state after a withdraw, but not promote them.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 9e81219692c494a39b65cc7ff5f3a32af88d23a4..959a19ced4d5f83fccf7e82c88a5855f3d1d26cc 100644 (file)
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -449,7 +449,8 @@ __acquires(&gl->gl_lockref.lock)
        unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
        int ret;
 
-       if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+       if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
+           target != LM_ST_UNLOCKED)
                return;
        lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
                      LM_FLAG_PRIORITY);
@@ -486,7 +487,8 @@ __acquires(&gl->gl_lockref.lock)
                }
                else if (ret) {
                        pr_err("lm_lock ret %d\n", ret);
-                       GLOCK_BUG_ON(gl, 1);
+                       GLOCK_BUG_ON(gl, !test_bit(SDF_SHUTDOWN,
+                                                  &sdp->sd_flags));
                }
        } else { /* lock_nolock */
                finish_xmote(gl, target);