[GFS2] Fix delayed demote race (265d529c) · Commits · 戴 / test

There is a race in the delayed demote code where it does the wrong thing if a demotion to UN has occurred for other reasons before the delay has expired. This patch adds an assert to catch that condition as well as fixing the root cause by adding an additional check for the UN state. Signed-off-by:

Steven Whitehouse <swhiteho@redhat.com> Cc: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/glock.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -587,6 +587,7 @@ static void run_queue(struct gfs2_glock *gl, const int nonblock)
		if (nonblock)
		goto out_sched;
		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
		gl->gl_target = gl->gl_demote_state;
		} else {
		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
		@@ -617,7 +618,9 @@ static void glock_work_func(struct work_struct *work)
		if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags))
		finish_xmote(gl, gl->gl_reply);
		spin_lock(&gl->gl_spin);
		if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags)) {
		if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
		gl->gl_state != LM_ST_UNLOCKED &&
		gl->gl_demote_state != LM_ST_EXCLUSIVE) {
		unsigned long holdtime, now = jiffies;
		holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
		if (time_before(now, holdtime))

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