[PATCH] ceph: clear `s_cap_reconnect` when ceph_pagelist_encode_32() fails

[Max Kellermann]

This MDS reconnect error path leaves s_cap_reconnect set.
send_mds_reconnect() sets the bit at the beginning of the reconnect,
but the first failing operation after that, ceph_pagelist_encode_32(),
can jump to `fail:` without clearing it.

__ceph_remove_cap() consults that flag to decide whether cap releases
should be queued. A reconnect-preparation failure therefore leaves the
session in reconnect mode from the cap-release path's point of view
and can strand release work until some later state transition repairs
it.

Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
---
 fs/ceph/mds_client.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index b1746273f186..4fa471d9b3b2 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4956,7 +4956,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 	/* placeholder for nr_caps */
 	err = ceph_pagelist_encode_32(recon_state.pagelist, 0);
 	if (err)
-		goto fail;
+		goto fail_clear_cap_reconnect;
 
 	if (test_bit(CEPHFS_FEATURE_MULTI_RECONNECT, &session->s_features)) {
 		recon_state.msg_version = 3;
@@ -5046,6 +5046,10 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 	ceph_pagelist_release(recon_state.pagelist);
 	return;
 
+fail_clear_cap_reconnect:
+	spin_lock(&session->s_cap_lock);
+	session->s_cap_reconnect = 0;
+	spin_unlock(&session->s_cap_lock);
 fail:
 	ceph_msg_put(reply);
 	up_read(&mdsc->snap_rwsem);
-- 
2.47.3