Merge tag 'gfs2-v5.10-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 fix from Andreas Gruenbacher:
 "Fix gfs2 freeze/thaw"

* tag 'gfs2-v5.10-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix regression in freeze_go_sync

1 files changed, 12 insertions, 1 deletions

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 6c1432d78dce65..67f2921ae8d4ab 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -571,7 +571,18 @@ static int freeze_go_sync(struct gfs2_glock *gl)
 	int error = 0;
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
-	if (gl->gl_req == LM_ST_EXCLUSIVE && !gfs2_withdrawn(sdp)) {
+	/*
+	 * We need to check gl_state == LM_ST_SHARED here and not gl_req ==
+	 * LM_ST_EXCLUSIVE. That's because when any node does a freeze,
+	 * all the nodes should have the freeze glock in SH mode and they all
+	 * call do_xmote: One for EX and the others for UN. They ALL must
+	 * freeze locally, and they ALL must queue freeze work. The freeze_work
+	 * calls freeze_func, which tries to reacquire the freeze glock in SH,
+	 * effectively waiting for the thaw on the node who holds it in EX.
+	 * Once thawed, the work func acquires the freeze glock in
+	 * SH and everybody goes back to thawed.
+	 */
+	if (gl->gl_state == LM_ST_SHARED && !gfs2_withdrawn(sdp)) {
 		atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
 		error = freeze_super(sdp->sd_vfs);
 		if (error) {