From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 19 Oct 2017 08:53:58 -0400
Subject: ceph: clean up spinlocking and list handling around
cleanup_cap_releases()
Git-commit: c8a96a31cb04c7664626ab6ada7f66c98c09efbd
Patch-mainline: v4.15-rc1
References: FATE#324714
Functions that release a lock taken in a parent frame are notoriously
hard to follow. Split cleanup_cap_releases into two functions, one to
detach the cap releases from the session (which should be called with
the spinlock held), and another to dispose of those caps.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/mds_client.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1038,22 +1038,23 @@ void ceph_mdsc_open_export_target_sessio
* session caps
*/
-/* caller holds s_cap_lock, we drop it */
-static void cleanup_cap_releases(struct ceph_mds_client *mdsc,
- struct ceph_mds_session *session)
- __releases(session->s_cap_lock)
+static void detach_cap_releases(struct ceph_mds_session *session,
+ struct list_head *target)
{
- LIST_HEAD(tmp_list);
- list_splice_init(&session->s_cap_releases, &tmp_list);
+ lockdep_assert_held(&session->s_cap_lock);
+
+ list_splice_init(&session->s_cap_releases, target);
session->s_num_cap_releases = 0;
- spin_unlock(&session->s_cap_lock);
+ dout("dispose_cap_releases mds%d\n", session->s_mds);
+}
- dout("cleanup_cap_releases mds%d\n", session->s_mds);
- while (!list_empty(&tmp_list)) {
+static void dispose_cap_releases(struct ceph_mds_client *mdsc,
+ struct list_head *dispose)
+{
+ while (!list_empty(dispose)) {
struct ceph_cap *cap;
/* zero out the in-progress message */
- cap = list_first_entry(&tmp_list,
- struct ceph_cap, session_caps);
+ cap = list_first_entry(dispose, struct ceph_cap, session_caps);
list_del(&cap->session_caps);
ceph_put_cap(mdsc, cap);
}
@@ -1250,6 +1251,8 @@ static void remove_session_caps(struct c
{
struct ceph_fs_client *fsc = session->s_mdsc->fsc;
struct super_block *sb = fsc->sb;
+ LIST_HEAD(dispose);
+
dout("remove_session_caps on %p\n", session);
iterate_session_caps(session, remove_session_caps_cb, fsc);
@@ -1284,10 +1287,12 @@ static void remove_session_caps(struct c
}
// drop cap expires and unlock s_cap_lock
- cleanup_cap_releases(session->s_mdsc, session);
+ detach_cap_releases(session, &dispose);
BUG_ON(session->s_nr_caps > 0);
BUG_ON(!list_empty(&session->s_cap_flushing));
+ spin_unlock(&session->s_cap_lock);
+ dispose_cap_releases(session->s_mdsc, &dispose);
}
/*
@@ -3014,6 +3019,7 @@ static void send_mds_reconnect(struct ce
int s_nr_caps;
struct ceph_pagelist *pagelist;
struct ceph_reconnect_state recon_state;
+ LIST_HEAD(dispose);
pr_info("mds%d reconnect start\n", mds);
@@ -3047,7 +3053,9 @@ static void send_mds_reconnect(struct ce
*/
session->s_cap_reconnect = 1;
/* drop old cap expires; we're about to reestablish that state */
- cleanup_cap_releases(mdsc, session);
+ detach_cap_releases(session, &dispose);
+ spin_unlock(&session->s_cap_lock);
+ dispose_cap_releases(mdsc, &dispose);
/* trim unused caps to reduce MDS's cache rejoin time */
if (mdsc->fsc->sb->s_root)