gfs2: release iopen glock early in evict

Before this patch, evict would clear the iopen glock's gl_object after
releasing the inode glock.  In the meantime, another process could reuse
the same block and thus glocks for a new inode.  It would lock the inode
glock (exclusively), and then the iopen glock (shared).  The shared
locking mode doesn't provide any ordering against the evict, so by the
time the iopen glock is reused, evict may not have gotten to setting
gl_object to NULL.

Fix that by releasing the iopen glock before the inode glock in
gfs2_evict_inode.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>gl_object
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 5b121371508a539da16a9fc89389a5019893f2e0..0f93e8beca4d957a12ea38420c04f95fc8e3da45 100644 (file)
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1402,13 +1402,6 @@ out:
        gfs2_ordered_del_inode(ip);
        clear_inode(inode);
        gfs2_dir_hash_inval(ip);
-       if (ip->i_gl) {
-               glock_clear_object(ip->i_gl, ip);
-               wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);
-               gfs2_glock_add_to_lru(ip->i_gl);
-               gfs2_glock_put_eventually(ip->i_gl);
-               ip->i_gl = NULL;
-       }
        if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
                struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
 
@@ -1421,6 +1414,13 @@ out:
                gfs2_holder_uninit(&ip->i_iopen_gh);
                gfs2_glock_put_eventually(gl);
        }
+       if (ip->i_gl) {
+               glock_clear_object(ip->i_gl, ip);
+               wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);
+               gfs2_glock_add_to_lru(ip->i_gl);
+               gfs2_glock_put_eventually(ip->i_gl);
+               ip->i_gl = NULL;
+       }
 }
 
 static struct inode *gfs2_alloc_inode(struct super_block *sb)