gfs2: Add common helper for holding and releasing the freeze glock

Many places in the gfs2 code queued and dequeued the freeze glock.
Almost all of them acquire it in SHARED mode, and need to specify the
same LM_FLAG_NOEXP and GL_EXACT flags.

This patch adds common helper functions gfs2_freeze_lock and gfs2_freeze_unlock
to make the code more readable, and to prepare for the next patch.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index a374397f4273..a115c441e2a1 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -91,6 +91,31 @@ out_unlock:
 	return error;
 }
 
+/**
+ * gfs2_freeze_lock - hold the freeze glock
+ * @sdp: the superblock
+ * @freeze_gh: pointer to the requested holder
+ * @caller_flags: any additional flags needed by the caller
+ */
+int gfs2_freeze_lock(struct gfs2_sbd *sdp, struct gfs2_holder *freeze_gh,
+		     int caller_flags)
+{
+	int flags = LM_FLAG_NOEXP | GL_EXACT | caller_flags;
+	int error;
+
+	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED, flags,
+				   freeze_gh);
+	if (error && error != GLR_TRYFAILED)
+		fs_err(sdp, "can't lock the freeze lock: %d\n", error);
+	return error;
+}
+
+void gfs2_freeze_unlock(struct gfs2_holder *freeze_gh)
+{
+	if (gfs2_holder_initialized(freeze_gh))
+		gfs2_glock_dq_uninit(freeze_gh);
+}
+
 static void signal_our_withdraw(struct gfs2_sbd *sdp)
 {
 	struct gfs2_glock *gl = sdp->sd_live_gh.gh_gl;