From 44c99757fae80e9db058e1f1d7419cf6472e9af1 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Sun, 22 Sep 2013 10:28:10 +0800 Subject: [PATCH] ceph: set caps count after composing cap reconnect message It's possible that some caps get released while composing the cap reconnect message. Signed-off-by: Yan, Zheng Reviewed-by: Sage Weil --- fs/ceph/mds_client.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 8f8f5c043c37..4a93d69abc8b 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -43,6 +43,7 @@ */ struct ceph_reconnect_state { + int nr_caps; struct ceph_pagelist *pagelist; bool flock; }; @@ -2549,6 +2550,8 @@ encode_again: } else { err = ceph_pagelist_append(pagelist, &rec, reclen); } + + recon_state->nr_caps++; out_free: kfree(path); out_dput: @@ -2576,6 +2579,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, struct rb_node *p; int mds = session->s_mds; int err = -ENOMEM; + int s_nr_caps; struct ceph_pagelist *pagelist; struct ceph_reconnect_state recon_state; @@ -2611,10 +2615,12 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, discard_cap_releases(mdsc, session); /* traverse this session's caps */ - err = ceph_pagelist_encode_32(pagelist, session->s_nr_caps); + s_nr_caps = session->s_nr_caps; + err = ceph_pagelist_encode_32(pagelist, s_nr_caps); if (err) goto fail; + recon_state.nr_caps = 0; recon_state.pagelist = pagelist; recon_state.flock = session->s_con.peer_features & CEPH_FEATURE_FLOCK; err = iterate_session_caps(session, encode_caps_cb, &recon_state); @@ -2643,11 +2649,18 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, if (recon_state.flock) reply->hdr.version = cpu_to_le16(2); - if (pagelist->length) { - /* set up outbound data if we have any */ - reply->hdr.data_len = cpu_to_le32(pagelist->length); - ceph_msg_data_add_pagelist(reply, pagelist); + + /* raced with cap release? */ + if (s_nr_caps != recon_state.nr_caps) { + struct page *page = list_first_entry(&pagelist->head, + struct page, lru); + __le32 *addr = kmap_atomic(page); + *addr = cpu_to_le32(recon_state.nr_caps); + kunmap_atomic(addr); } + + reply->hdr.data_len = cpu_to_le32(pagelist->length); + ceph_msg_data_add_pagelist(reply, pagelist); ceph_con_send(&session->s_con, reply); mutex_unlock(&session->s_mutex); -- 2.20.1