In gfs2_kill_sb(), flush the delete work queue after setting the
SDF_DEACTIVATING flag.  This ensures that no new inodes will be
instantiated anymore, and the inode cache will be empty after the
following kill_block_super() -> generic_shutdown_super() ->
evict_inodes() call.
With that, function gfs2_make_fs_ro() now calls gfs2_flush_delete_work()
after the workqueue has been destroyed.  Skip that by checking for the
presence of the SDF_DEACTIVATING flag.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
        sdp->sd_root_dir = NULL;
        sdp->sd_master_dir = NULL;
        shrink_dcache_sb(sb);
+
+       /*
+        * Flush and then drain the delete workqueue here (via
+        * destroy_workqueue()) to ensure that any delete work that
+        * may be running will also see the SDF_DEACTIVATING flag.
+        */
        set_bit(SDF_DEACTIVATING, &sdp->sd_flags);
+       gfs2_flush_delete_work(sdp);
+       destroy_workqueue(sdp->sd_delete_wq);
+
        kill_block_super(sb);
 }
 
 
 {
        int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 
-       gfs2_flush_delete_work(sdp);
+       if (!test_bit(SDF_DEACTIVATING, &sdp->sd_flags))
+               gfs2_flush_delete_work(sdp);
+
        if (!log_write_allowed && current == sdp->sd_quotad_process)
                fs_warn(sdp, "The quotad daemon is withdrawing.\n");
        else if (sdp->sd_quotad_process)
        /*  Unmount the locking protocol  */
        gfs2_lm_unmount(sdp);
 
-       destroy_workqueue(sdp->sd_delete_wq);
-
        /*  At this point, we're through participating in the lockspace  */
        gfs2_sys_fs_del(sdp);
        free_sbd(sdp);