I haven't looked at all the called functions, to see if any of them drops
the lock, but it could be worth a check.
julia
On Fri, 3 Jul 2015, kbuild test robot wrote:
> TO: "Yan, Zheng" <zyan@xxxxxxxxxx>
> CC: Ilya Dryomov <idryomov@xxxxxxxxx>
> CC: ceph-devel@xxxxxxxxxxxxxxx
>
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client.git for-linus
> head: 5a60e87603c4c533492c515b7f62578189b03c9c
> commit: 745a8e3bccbc6adae69a98ddc525e529aa44636e [11/40] ceph: don't pre-allocate space for cap release messages
> :::::: branch date: 2 days ago
> :::::: commit date: 7 days ago
>
> >> fs/ceph/mds_client.c:2865:1-10: second lock on line 2904
> --
> >> fs/ceph/mds_client.c:2961:1-7: preceding lock on line 2865
>
> git remote add ceph git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client.git
> git remote update ceph
> git checkout 745a8e3bccbc6adae69a98ddc525e529aa44636e
> vim +2865 fs/ceph/mds_client.c
>
> a687ecaf John Spray 2014-09-19 2859 ceph_session_state_name(session->s_state));
> 2f2dc053 Sage Weil 2009-10-06 2860
> 99a9c273 Yan, Zheng 2013-09-22 2861 spin_lock(&session->s_gen_ttl_lock);
> 99a9c273 Yan, Zheng 2013-09-22 2862 session->s_cap_gen++;
> 99a9c273 Yan, Zheng 2013-09-22 2863 spin_unlock(&session->s_gen_ttl_lock);
> 99a9c273 Yan, Zheng 2013-09-22 2864
> 99a9c273 Yan, Zheng 2013-09-22 @2865 spin_lock(&session->s_cap_lock);
> 03f4fcb0 Yan, Zheng 2015-01-05 2866 /* don't know if session is readonly */
> 03f4fcb0 Yan, Zheng 2015-01-05 2867 session->s_readonly = 0;
> 99a9c273 Yan, Zheng 2013-09-22 2868 /*
> 99a9c273 Yan, Zheng 2013-09-22 2869 * notify __ceph_remove_cap() that we are composing cap reconnect.
> 99a9c273 Yan, Zheng 2013-09-22 2870 * If a cap get released before being added to the cap reconnect,
> 99a9c273 Yan, Zheng 2013-09-22 2871 * __ceph_remove_cap() should skip queuing cap release.
> 99a9c273 Yan, Zheng 2013-09-22 2872 */
> 99a9c273 Yan, Zheng 2013-09-22 2873 session->s_cap_reconnect = 1;
> e01a5946 Sage Weil 2010-05-10 2874 /* drop old cap expires; we're about to reestablish that state */
> 745a8e3b Yan, Zheng 2015-05-14 2875 cleanup_cap_releases(mdsc, session);
> e01a5946 Sage Weil 2010-05-10 2876
> 5d23371f Yan, Zheng 2014-09-10 2877 /* trim unused caps to reduce MDS's cache rejoin time */
> c0bd50e2 Yan, Zheng 2015-04-07 2878 if (mdsc->fsc->sb->s_root)
> 5d23371f Yan, Zheng 2014-09-10 2879 shrink_dcache_parent(mdsc->fsc->sb->s_root);
> 5d23371f Yan, Zheng 2014-09-10 2880
> 5d23371f Yan, Zheng 2014-09-10 2881 ceph_con_close(&session->s_con);
> 5d23371f Yan, Zheng 2014-09-10 2882 ceph_con_open(&session->s_con,
> 5d23371f Yan, Zheng 2014-09-10 2883 CEPH_ENTITY_TYPE_MDS, mds,
> 5d23371f Yan, Zheng 2014-09-10 2884 ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
> 5d23371f Yan, Zheng 2014-09-10 2885
> 5d23371f Yan, Zheng 2014-09-10 2886 /* replay unsafe requests */
> 5d23371f Yan, Zheng 2014-09-10 2887 replay_unsafe_requests(mdsc, session);
> 5d23371f Yan, Zheng 2014-09-10 2888
> 5d23371f Yan, Zheng 2014-09-10 2889 down_read(&mdsc->snap_rwsem);
> 5d23371f Yan, Zheng 2014-09-10 2890
> 2f2dc053 Sage Weil 2009-10-06 2891 /* traverse this session's caps */
> 44c99757 Yan, Zheng 2013-09-22 2892 s_nr_caps = session->s_nr_caps;
> 44c99757 Yan, Zheng 2013-09-22 2893 err = ceph_pagelist_encode_32(pagelist, s_nr_caps);
> 93cea5be Sage Weil 2009-12-23 2894 if (err)
> 93cea5be Sage Weil 2009-12-23 2895 goto fail;
> 20cb34ae Sage Weil 2010-05-12 2896
> 44c99757 Yan, Zheng 2013-09-22 2897 recon_state.nr_caps = 0;
> 20cb34ae Sage Weil 2010-05-12 2898 recon_state.pagelist = pagelist;
> 20cb34ae Sage Weil 2010-05-12 2899 recon_state.flock = session->s_con.peer_features & CEPH_FEATURE_FLOCK;
> 20cb34ae Sage Weil 2010-05-12 2900 err = iterate_session_caps(session, encode_caps_cb, &recon_state);
> 2f2dc053 Sage Weil 2009-10-06 2901 if (err < 0)
> 9abf82b8 Sage Weil 2010-05-10 2902 goto fail;
> 2f2dc053 Sage Weil 2009-10-06 2903
> 99a9c273 Yan, Zheng 2013-09-22 @2904 spin_lock(&session->s_cap_lock);
> 99a9c273 Yan, Zheng 2013-09-22 2905 session->s_cap_reconnect = 0;
> 99a9c273 Yan, Zheng 2013-09-22 2906 spin_unlock(&session->s_cap_lock);
> 99a9c273 Yan, Zheng 2013-09-22 2907
> 2f2dc053 Sage Weil 2009-10-06 2908 /*
> 2f2dc053 Sage Weil 2009-10-06 2909 * snaprealms. we provide mds with the ino, seq (version), and
> 2f2dc053 Sage Weil 2009-10-06 2910 * parent for all of our realms. If the mds has any newer info,
> 2f2dc053 Sage Weil 2009-10-06 2911 * it will tell us.
> 2f2dc053 Sage Weil 2009-10-06 2912 */
> a105f00c Sage Weil 2010-02-15 2913 for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
> a105f00c Sage Weil 2010-02-15 2914 struct ceph_snap_realm *realm =
> a105f00c Sage Weil 2010-02-15 2915 rb_entry(p, struct ceph_snap_realm, node);
> 93cea5be Sage Weil 2009-12-23 2916 struct ceph_mds_snaprealm_reconnect sr_rec;
> 2f2dc053 Sage Weil 2009-10-06 2917
> 2f2dc053 Sage Weil 2009-10-06 2918 dout(" adding snap realm %llx seq %lld parent %llx\n",
> 2f2dc053 Sage Weil 2009-10-06 2919 realm->ino, realm->seq, realm->parent_ino);
> 93cea5be Sage Weil 2009-12-23 2920 sr_rec.ino = cpu_to_le64(realm->ino);
> 93cea5be Sage Weil 2009-12-23 2921 sr_rec.seq = cpu_to_le64(realm->seq);
> 93cea5be Sage Weil 2009-12-23 2922 sr_rec.parent = cpu_to_le64(realm->parent_ino);
> 93cea5be Sage Weil 2009-12-23 2923 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
> 93cea5be Sage Weil 2009-12-23 2924 if (err)
> 93cea5be Sage Weil 2009-12-23 2925 goto fail;
> 2f2dc053 Sage Weil 2009-10-06 2926 }
> 2f2dc053 Sage Weil 2009-10-06 2927
> 20cb34ae Sage Weil 2010-05-12 2928 if (recon_state.flock)
> 20cb34ae Sage Weil 2010-05-12 2929 reply->hdr.version = cpu_to_le16(2);
> 44c99757 Yan, Zheng 2013-09-22 2930
> 44c99757 Yan, Zheng 2013-09-22 2931 /* raced with cap release? */
> 44c99757 Yan, Zheng 2013-09-22 2932 if (s_nr_caps != recon_state.nr_caps) {
> 44c99757 Yan, Zheng 2013-09-22 2933 struct page *page = list_first_entry(&pagelist->head,
> 44c99757 Yan, Zheng 2013-09-22 2934 struct page, lru);
> 44c99757 Yan, Zheng 2013-09-22 2935 __le32 *addr = kmap_atomic(page);
> 44c99757 Yan, Zheng 2013-09-22 2936 *addr = cpu_to_le32(recon_state.nr_caps);
> 44c99757 Yan, Zheng 2013-09-22 2937 kunmap_atomic(addr);
> 44c99757 Yan, Zheng 2013-09-22 2938 }
> 44c99757 Yan, Zheng 2013-09-22 2939
> 93cea5be Sage Weil 2009-12-23 2940 reply->hdr.data_len = cpu_to_le32(pagelist->length);
> 90af3602 Alex Elder 2013-04-05 2941 ceph_msg_data_add_pagelist(reply, pagelist);
> 2f2dc053 Sage Weil 2009-10-06 2942 ceph_con_send(&session->s_con, reply);
> 2f2dc053 Sage Weil 2009-10-06 2943
> 9abf82b8 Sage Weil 2010-05-10 2944 mutex_unlock(&session->s_mutex);
> 9abf82b8 Sage Weil 2010-05-10 2945
> 9abf82b8 Sage Weil 2010-05-10 2946 mutex_lock(&mdsc->mutex);
> 2f2dc053 Sage Weil 2009-10-06 2947 __wake_requests(mdsc, &session->s_waiting);
> 9abf82b8 Sage Weil 2010-05-10 2948 mutex_unlock(&mdsc->mutex);
> 2f2dc053 Sage Weil 2009-10-06 2949
> 9abf82b8 Sage Weil 2010-05-10 2950 up_read(&mdsc->snap_rwsem);
> 2f2dc053 Sage Weil 2009-10-06 2951 return;
> 2f2dc053 Sage Weil 2009-10-06 2952
> 93cea5be Sage Weil 2009-12-23 2953 fail:
> 2f2dc053 Sage Weil 2009-10-06 2954 ceph_msg_put(reply);
> 9abf82b8 Sage Weil 2010-05-10 2955 up_read(&mdsc->snap_rwsem);
> 9abf82b8 Sage Weil 2010-05-10 2956 mutex_unlock(&session->s_mutex);
> 93cea5be Sage Weil 2009-12-23 2957 fail_nomsg:
> 93cea5be Sage Weil 2009-12-23 2958 ceph_pagelist_release(pagelist);
> 93cea5be Sage Weil 2009-12-23 2959 fail_nopagelist:
> 9abf82b8 Sage Weil 2010-05-10 2960 pr_err("error %d preparing reconnect for mds%d\n", err, mds);
> 9abf82b8 Sage Weil 2010-05-10 @2961 return;
> 2f2dc053 Sage Weil 2009-10-06 2962 }
> 2f2dc053 Sage Weil 2009-10-06 2963
> 2f2dc053 Sage Weil 2009-10-06 2964
>
> :::::: The code at line 2865 was first introduced by commit
> :::::: 99a9c273b94a087f8feaec6c5ffbe3205a2dbe51 ceph: handle race between cap reconnect and cap release
>
> :::::: TO: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> :::::: CC: Sage Weil <sage@xxxxxxxxxxx>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
>
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