From c8a96a31cb04c7664626ab6ada7f66c98c09efbd Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 19 Oct 2017 08:53:58 -0400 Subject: ceph: clean up spinlocking and list handling around cleanup_cap_releases() 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 Reviewed-by: "Yan, Zheng" Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov --- fs/ceph/mds_client.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index b76506be4228..53cde84e698a 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1039,22 +1039,23 @@ void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc, * 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); } @@ -1251,6 +1252,8 @@ static void remove_session_caps(struct ceph_mds_session *session) { 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); @@ -1285,10 +1288,12 @@ static void remove_session_caps(struct ceph_mds_session *session) } // 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); } /* @@ -3015,6 +3020,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, 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); @@ -3048,7 +3054,9 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, */ 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) -- cgit v1.2.3-55-g7522