linux-kernel - [PATCH 5.7 051/244] gfs2: freeze should work on read-only mounts

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Date:   Mon, 20 Jul 2020 17:35:22 +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 5.7 051/244] gfs2: freeze should work on read-only mounts

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

[ Upstream commit 541656d3a5136ae830d604e237f29f406d42c592 ]

Before this patch, function freeze_go_sync, called when promoting
the freeze glock, was testing for the SDF_JOURNAL_LIVE superblock flag.
That's only set for read-write mounts. Read-only mounts don't use a
journal, so the bit is never set, so the freeze never happened.

This patch removes the check for SDF_JOURNAL_LIVE for freeze requests
but still checks it when deciding whether to flush a journal.

Signed-off-by: Bob Peterson <rpeterso@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/gfs2/glops.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 9e9c7a4b8c663..fc97c4d24dc58 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -527,8 +527,7 @@ static int freeze_go_sync(struct gfs2_glock *gl)
 	int error = 0;
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
-	if (gl->gl_state == LM_ST_SHARED && !gfs2_withdrawn(sdp) &&
-	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
+	if (gl->gl_req == LM_ST_EXCLUSIVE && !gfs2_withdrawn(sdp)) {
 		atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
 		error = freeze_super(sdp->sd_vfs);
 		if (error) {
@@ -541,8 +540,11 @@ static int freeze_go_sync(struct gfs2_glock *gl)
 			gfs2_assert_withdraw(sdp, 0);
 		}
 		queue_work(gfs2_freeze_wq, &sdp->sd_freeze_work);
-		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
-			       GFS2_LFC_FREEZE_GO_SYNC);
+		if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
+			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
+				       GFS2_LFC_FREEZE_GO_SYNC);
+		else /* read-only mounts */
+			atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
 	}
 	return 0;
 }
-- 
2.25.1