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

[ Upstream commit c77b52c0a137994ad796f44544c802b0b766e496 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/gfs2/ops_fstype.c

@@ -1198,14 +1198,12 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (sb_rdonly(sb)) {
 		struct gfs2_holder freeze_gh;
 
-		error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
-					   LM_FLAG_NOEXP | GL_EXACT,
-					   &freeze_gh);
+		error = gfs2_freeze_lock(sdp, &freeze_gh, 0);
 		if (error) {
 			fs_err(sdp, "can't make FS RO: %d\n", error);
 			goto fail_per_node;
 		}
-		gfs2_glock_dq_uninit(&freeze_gh);
+		gfs2_freeze_unlock(&freeze_gh);
 	} else {
 		error = gfs2_make_fs_rw(sdp);
 		if (error) {

fs/gfs2/recovery.c

@@ -470,9 +470,7 @@ void gfs2_recover_func(struct work_struct *work)
 
 		/* Acquire a shared hold on the freeze lock */
 
-		error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
-					   LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
-					   GL_EXACT, &thaw_gh);
+		error = gfs2_freeze_lock(sdp, &thaw_gh, LM_FLAG_PRIORITY);
 		if (error)
 			goto fail_gunlock_ji;
 
@@ -524,7 +522,7 @@ void gfs2_recover_func(struct work_struct *work)
 		clean_journal(jd, &head);
 		up_read(&sdp->sd_log_flush_lock);
 
-		gfs2_glock_dq_uninit(&thaw_gh);
+		gfs2_freeze_unlock(&thaw_gh);
 		t_rep = ktime_get();
 		fs_info(sdp, "jid=%u: Journal replayed in %lldms [jlck:%lldms, "
 			"jhead:%lldms, tlck:%lldms, replay:%lldms]\n",
@@ -546,7 +544,7 @@ void gfs2_recover_func(struct work_struct *work)
 	goto done;
 
 fail_gunlock_thaw:
-	gfs2_glock_dq_uninit(&thaw_gh);
+	gfs2_freeze_unlock(&thaw_gh);
 fail_gunlock_ji:
 	if (jlocked) {
 		gfs2_glock_dq_uninit(&ji_gh);

fs/gfs2/super.c

@@ -173,9 +173,7 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
 	if (error)
 		return error;
 
-	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
-				   LM_FLAG_NOEXP | GL_EXACT,
-				   &freeze_gh);
+	error = gfs2_freeze_lock(sdp, &freeze_gh, 0);
 	if (error)
 		goto fail_threads;
 
@@ -205,12 +203,12 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
 
 	set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 
-	gfs2_glock_dq_uninit(&freeze_gh);
+	gfs2_freeze_unlock(&freeze_gh);
 
 	return 0;
 
 fail:
-	gfs2_glock_dq_uninit(&freeze_gh);
+	gfs2_freeze_unlock(&freeze_gh);
 fail_threads:
 	if (sdp->sd_quotad_process)
 		kthread_stop(sdp->sd_quotad_process);
@@ -454,7 +452,7 @@ static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp)
 	}
 
 	if (error)
-		gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
+		gfs2_freeze_unlock(&sdp->sd_freeze_gh);
 
 out:
 	while (!list_empty(&list)) {
@@ -618,21 +616,12 @@ int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
 	gfs2_holder_mark_uninitialized(&freeze_gh);
 	if (sdp->sd_freeze_gl &&
 	    !gfs2_glock_is_locked_by_me(sdp->sd_freeze_gl)) {
-		if (!log_write_allowed) {
-			error = gfs2_glock_nq_init(sdp->sd_freeze_gl,
-						   LM_ST_SHARED, LM_FLAG_TRY |
-						   LM_FLAG_NOEXP | GL_EXACT,
-						   &freeze_gh);
-			if (error == GLR_TRYFAILED)
-				error = 0;
-		} else {
-			error = gfs2_glock_nq_init(sdp->sd_freeze_gl,
-						   LM_ST_SHARED,
-						   LM_FLAG_NOEXP | GL_EXACT,
-						   &freeze_gh);
-			if (error && !gfs2_withdrawn(sdp))
-				return error;
-		}
+		error = gfs2_freeze_lock(sdp, &freeze_gh,
+					 log_write_allowed ? 0 : LM_FLAG_TRY);
+		if (error == GLR_TRYFAILED)
+			error = 0;
+		if (error && !gfs2_withdrawn(sdp))
+			return error;
 	}
 
 	gfs2_flush_delete_work(sdp);
@@ -663,8 +652,7 @@ int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
 				   atomic_read(&sdp->sd_reserving_log) == 0,
 				   HZ * 5);
 	}
-	if (gfs2_holder_initialized(&freeze_gh))
-		gfs2_glock_dq_uninit(&freeze_gh);
+	gfs2_freeze_unlock(&freeze_gh);
 
 	gfs2_quota_cleanup(sdp);
 
@@ -774,10 +762,8 @@ void gfs2_freeze_func(struct work_struct *work)
 	struct super_block *sb = sdp->sd_vfs;
 
 	atomic_inc(&sb->s_active);
-	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
-				   LM_FLAG_NOEXP | GL_EXACT, &freeze_gh);
+	error = gfs2_freeze_lock(sdp, &freeze_gh, 0);
 	if (error) {
-		fs_info(sdp, "GFS2: couldn't get freeze lock : %d\n", error);
 		gfs2_assert_withdraw(sdp, 0);
 	} else {
 		atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
@@ -787,7 +773,7 @@ void gfs2_freeze_func(struct work_struct *work)
 				error);
 			gfs2_assert_withdraw(sdp, 0);
 		}
-		gfs2_glock_dq_uninit(&freeze_gh);
+		gfs2_freeze_unlock(&freeze_gh);
 	}
 	deactivate_super(sb);
 	clear_bit_unlock(SDF_FS_FROZEN, &sdp->sd_flags);
@@ -855,7 +841,7 @@ static int gfs2_unfreeze(struct super_block *sb)
                 return 0;
 	}
 
-	gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
+	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
 	mutex_unlock(&sdp->sd_freeze_mutex);
 	return wait_on_bit(&sdp->sd_flags, SDF_FS_FROZEN, TASK_INTERRUPTIBLE);
 }

fs/gfs2/util.c

@@ -91,6 +91,31 @@ int check_journal_clean(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 	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 *live_gl = sdp->sd_live_gh.gh_gl;

fs/gfs2/util.h

@@ -149,6 +149,9 @@ int gfs2_io_error_i(struct gfs2_sbd *sdp, const char *function,
 
 extern int check_journal_clean(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 			       bool verbose);
+extern int gfs2_freeze_lock(struct gfs2_sbd *sdp,
+			    struct gfs2_holder *freeze_gh, int caller_flags);
+extern void gfs2_freeze_unlock(struct gfs2_holder *freeze_gh);
 
 #define gfs2_io_error(sdp) \
 gfs2_io_error_i((sdp), __func__, __FILE__, __LINE__);