linux-kernel - [PATCH 5.17 017/158] gfs2: cancel timed-out glock requests

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Date:   Mon, 23 May 2022 19:02:54 +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, Andreas Gruenbacher <agruenba@...hat.com>,
        Bob Peterson <rpeterso@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.17 017/158] gfs2: cancel timed-out glock requests

From: Andreas Gruenbacher <agruenba@...hat.com>

[ Upstream commit 1fc05c8d8426d4085a219c23f8855c4aaf9e3ffb ]

The gfs2 evict code tries to upgrade the iopen glock from SH to EX. If
the attempt to upgrade times out, gfs2 needs to tell dlm to cancel the
lock request or it can deadlock. We also need to wake up the process
waiting for the lock when dlm sends its AST back to gfs2.

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

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 6b23399eaee0..d368d9a2e8f0 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -669,6 +669,8 @@ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 
 	/* Check for state != intended state */
 	if (unlikely(state != gl->gl_target)) {
+		if (gh && (ret & LM_OUT_CANCELED))
+			gfs2_holder_wake(gh);
 		if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
 			/* move to back of queue and try next entry */
 			if (ret & LM_OUT_CANCELED) {
@@ -1691,6 +1693,14 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 	struct gfs2_glock *gl = gh->gh_gl;
 
 	spin_lock(&gl->gl_lockref.lock);
+	if (list_is_first(&gh->gh_list, &gl->gl_holders) &&
+	    !test_bit(HIF_HOLDER, &gh->gh_iflags)) {
+		spin_unlock(&gl->gl_lockref.lock);
+		gl->gl_name.ln_sbd->sd_lockstruct.ls_ops->lm_cancel(gl);
+		wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
+		spin_lock(&gl->gl_lockref.lock);
+	}
+
 	__gfs2_glock_dq(gh);
 	spin_unlock(&gl->gl_lockref.lock);
 }
-- 
2.35.1