linux-kernel - [PATCH 5.7 054/244] gfs2: The freeze glock should never be frozen

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Message-Id: <20200720152828.430187312@linuxfoundation.org>
Date:   Mon, 20 Jul 2020 17:35:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Bob Peterson <rpeterso@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.7 054/244] gfs2: The freeze glock should never be frozen

From: Bob Peterson <rpeterso@...hat.com>

[ Upstream commit c860f8ffbea8924de05a281b937128773d30a77c ]

Before this patch, some gfs2 code locked the freeze glock with LM_FLAG_NOEXP
(Do not freeze) flag, and some did not. We never want to freeze the freeze
glock, so this patch makes it consistently use LM_FLAG_NOEXP always.

Signed-off-by: Bob Peterson <rpeterso@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/gfs2/ops_fstype.c |  3 ++-
 fs/gfs2/super.c      | 16 +++++++++-------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index a2c0554a18901..6d18d2c91add2 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1140,7 +1140,8 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
 		struct gfs2_holder freeze_gh;
 
 		error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
-					   GL_EXACT, &freeze_gh);
+					   LM_FLAG_NOEXP | GL_EXACT,
+					   &freeze_gh);
 		if (error) {
 			fs_err(sdp, "can't make FS RO: %d\n", error);
 			goto fail_per_node;
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 3bc76cf382fb9..160bb4598b48b 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -167,7 +167,8 @@ 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, GL_EXACT,
+	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
+				   LM_FLAG_NOEXP | GL_EXACT,
 				   &freeze_gh);
 	if (error)
 		goto fail_threads;
@@ -429,7 +430,7 @@ static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp)
 	}
 
 	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_EXCLUSIVE,
-				   0, &sdp->sd_freeze_gh);
+				   LM_FLAG_NOEXP, &sdp->sd_freeze_gh);
 	if (error)
 		goto out;
 
@@ -612,14 +613,15 @@ int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
 	    !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 | GL_EXACT,
+						   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, GL_EXACT,
+						   LM_ST_SHARED,
+						   LM_FLAG_NOEXP | GL_EXACT,
 						   &freeze_gh);
 			if (error && !gfs2_withdrawn(sdp))
 				return error;
@@ -761,8 +763,8 @@ 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, GL_EXACT,
-				   &freeze_gh);
+	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
+				   LM_FLAG_NOEXP | GL_EXACT, &freeze_gh);
 	if (error) {
 		fs_info(sdp, "GFS2: couldn't get freeze lock : %d\n", error);
 		gfs2_assert_withdraw(sdp, 0);
-- 
2.25.1