[Gluster-users] not to reconnect between client and server because of race condition

Kaushal M kshlmster at gmail.com
Fri Nov 25 06:57:56 UTC 2016


On Fri, Nov 25, 2016 at 12:03 PM, songxin <songxin_1980 at 126.com> wrote:
> Hi Atin
> I found a  problem, that is about client(glusterfs) will not trying to
> reconnect to server(glusterfsd) after disconnect.
> Actually, it seems caused by race condition.
>
>
> Precondition
>
> The glusterfs version is 3.7.6.
> I create a replicate volume using two node, A node and B node.One brick is
> on A node and another brick is on B node.
> A node ip:10.32.1.144
> B node ip:10.32.0.48
>
>
> The phenomenon is following.
>
> Firstly, the client(glusterfs) on A board disconnect with server(glusterfsd)
> on B board.The log is following.
> ...
> readv on 10.32.0.48:49309 failed (No data available)
> ...
>
> And then the client(glusterfs) on A board disconnect with server(glusterfsd)
> on A board.The log is following.
> ...
> readv on 10.32.1.144:49391 failed (Connection reset by peer)
> ...
>
> After that, all operation in mount point will show "Transport endpoint is
> not connected" until client reconnect with server(glusterfsd) on B board.
>
>
> The client log is following.And I have highlight the important line.
> ...
> [2016-10-31 04:06:03.626047] W [socket.c:588:__socket_rwv]
> 0-c_glusterfs-client-9: readv on 10.32.1.144:49391 failed (Connection reset
> by peer)
> [2016-10-31 04:06:03.627345] E [rpc-clnt.c:362:saved_frames_unwind] (-->
> /usr/lib64/libglusterfs.so.0(_gf_log_callingfn-0xb5c80)[0x3fff8ab79f58] (
>                                                                      -->
> /usr/lib64/libgfrpc.so.0(saved_frames_unwind-0x1b7a0)[0x3fff8ab1dc90] (
>                                                                      -->
> /usr/lib64/libgfrpc.so.0(saved_frames_destroy-0x1b638)[0x3fff8ab1de10] (
>                                                                      -->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_connection_cleanup-0x19af8)[0x3fff8ab1fb18]
> (
>                                                                      -->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_notify-0x18e68)[0x3fff8ab20808] )))))
>
> 0-c_glusterfs-client-9: forced unwinding frame type(GlusterFS 3.3)
>
> op(FINODELK(30)) called at 2016-10-31 04:06:03.626033 (xid=0x7f5e)
>
> [2016-10-31 04:06:03.627395] E [MSGID: 114031]
> [client-rpc-fops.c:1673:client3_3_finodelk_cbk] 0-c_glusterfs-client-9:
> remote operation failed [Transport endpoint is not connected]
>
> [2016-10-31 04:06:03.628381] I [socket.c:3308:socket_submit_request]
> 0-c_glusterfs-client-9: not connected (priv->connected = 0)
>
> [2016-10-31 04:06:03.628432] W [rpc-clnt.c:1586:rpc_clnt_submit]
> 0-c_glusterfs-client-9: failed to submit rpc-request (XID: 0x7f5f Program:
> GlusterFS 3.3, ProgVers: 330, Proc: 30) to rpc-transport
> (c_glusterfs-client-9)
>
> [2016-10-31 04:06:03.628466] E [MSGID: 114031]
> [client-rpc-fops.c:1673:client3_3_finodelk_cbk] 0-c_glusterfs-client-9:
> remote operation failed [Transport endpoint is not connected]
> [2016-10-31 04:06:03.628475] I [MSGID: 108019]
> [afr-lk-common.c:1086:afr_lock_blocking] 0-c_glusterfs-replicate-0: unable
> to lock on even one child
>
> [2016-10-31 04:06:03.628539] I [MSGID: 108019]
> [afr-transaction.c:1224:afr_post_blocking_inodelk_cbk]
> 0-c_glusterfs-replicate-0: Blocking inodelks failed.
>
> [2016-10-31 04:06:03.628630] W [fuse-bridge.c:1282:fuse_err_cbk]
> 0-glusterfs-fuse: 20790: FLUSH() ERR => -1 (Transport endpoint is not
> connected)
> [2016-10-31 04:06:03.629149] E [rpc-clnt.c:362:saved_frames_unwind] (-->
> /usr/lib64/libglusterfs.so.0(_gf_log_callingfn-0xb5c80)[0x3fff8ab79f58] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_unwind-0x1b7a0)[0x3fff8ab1dc90] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_destroy-0x1b638)[0x3fff8ab1de10] (-->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_connection_cleanup-0x19af8)[0x3fff8ab1fb18]
> (--> /usr/lib64/libgfrpc.so.0(rpc_clnt_notify-0x18e68)[0x3fff8ab20808] )))))
> 0-c_glusterfs-client-9: forced unwinding frame type(GlusterFS 3.3)
> op(LOOKUP(27)) called at 2016-10-31 04:06:03.624346 (xid=0x7f5a)
>
> [2016-10-31 04:06:03.629183] I [rpc-clnt.c:1847:rpc_clnt_reconfig]
> 0-c_glusterfs-client-9: changing port to 49391 (from 0)
>
> [2016-10-31 04:06:03.629210] W [MSGID: 114031]
> [client-rpc-fops.c:2971:client3_3_lookup_cbk] 0-c_glusterfs-client-9: remote
> operation failed. Path:
> /loadmodules_norepl/CXC1725605_P93A001/cello/emasviews
> (b0e5a94e-a432-4dce-b86f-a551555780a2) [Transport endpoint is not connected]
> [2016-10-31 04:06:03.629266] I [socket.c:3308:socket_submit_request]
> 0-c_glusterfs-client-9: not connected (priv->connected = 255)
> [2016-10-31 04:06:03.629277] I [MSGID: 109063]
> [dht-layout.c:702:dht_layout_normalize] 0-c_glusterfs-dht: Found anomalies
> in /loadmodules_norepl/CXC1725605_P93A001/cello/emasviews (gfid =
> b0e5a94e-a432-4dce-b86f-a551555780a2). Holes=1 overlaps=0
> [2016-10-31 04:06:03.629293] W [rpc-clnt.c:1586:rpc_clnt_submit]
> 0-c_glusterfs-client-9: failed to submit rpc-request (XID: 0x7f62 Program:
> GlusterFS 3.3, ProgVers: 330, Proc: 41) to rpc-transport
> (c_glusterfs-client-9)
> [2016-10-31 04:06:03.629333] W [fuse-resolve.c:149:fuse_resolve_gfid_cbk]
> 0-fuse: b0e5a94e-a432-4dce-b86f-a551555780a2: failed to resolve (Transport
> endpoint is not connected)
> [2016-10-31 04:06:03.629363] W [fuse-bridge.c:3385:fuse_getxattr_resume]
> 0-glusterfs-fuse: 20784: GETXATTR
> b0e5a94e-a432-4dce-b86f-a551555780a2/70366685109140
> (system.posix_acl_access) resolution failed
> [2016-10-31 04:06:03.629729] E [rpc-clnt.c:362:saved_frames_unwind] (-->
> /usr/lib64/libglusterfs.so.0(_gf_log_callingfn-0xb5c80)[0x3fff8ab79f58] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_unwind-0x1b7a0)[0x3fff8ab1dc90] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_destroy-0x1b638)[0x3fff8ab1de10] (-->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_connection_cleanup-0x19af8)[0x3fff8ab1fb18]
> (--> /usr/lib64/libgfrpc.so.0(rpc_clnt_notify-0x18e68)[0x3fff8ab20808] )))))
> 0-c_glusterfs-client-9: forced unwinding frame type(GlusterFS 3.3)
> op(LOOKUP(27)) called at 2016-10-31 04:06:03.624568 (xid=0x7f5b)
> [2016-10-31 04:06:03.629779] W [MSGID: 114031]
> [client-rpc-fops.c:2971:client3_3_lookup_cbk] 0-c_glusterfs-client-9: remote
> operation failed. Path: /pmd/2 (fa866805-ab22-4afe-8acb-528d15ce4117)
> [Transport endpoint is not connected]
> [2016-10-31 04:06:03.629784] E [MSGID: 114031]
> [client-rpc-fops.c:2883:client3_3_opendir_cbk] 0-c_glusterfs-client-9:
> remote operation failed. Path:
> /loadmodules_norepl/CXC1725605_P93A001/cello/emasviews
> (b0e5a94e-a432-4dce-b86f-a551555780a2) [Transport endpoint is not connected]
> [2016-10-31 04:06:03.629836] I [MSGID: 109063]
> [dht-layout.c:702:dht_layout_normalize] 0-c_glusterfs-dht: Found anomalies
> in /pmd/2 (gfid = fa866805-ab22-4afe-8acb-528d15ce4117). Holes=1 overlaps=0
> [2016-10-31 04:06:03.629857] W [fuse-bridge.c:980:fuse_fd_cbk]
> 0-glusterfs-fuse: 20794: OPENDIR()
> /loadmodules_norepl/CXC1725605_P93A001/cello/emasviews => -1 (Transport
> endpoint is not connected)
> [2016-10-31 04:06:03.629896] W [fuse-resolve.c:149:fuse_resolve_gfid_cbk]
> 0-fuse: fa866805-ab22-4afe-8acb-528d15ce4117: failed to resolve (Transport
> endpoint is not connected)
> [2016-10-31 04:06:03.629990] E [fuse-bridge.c:787:fuse_getattr_resume]
> 0-glusterfs-fuse: 20785: GETATTR 70366685017568
> (fa866805-ab22-4afe-8acb-528d15ce4117) resolution failed
> [2016-10-31 04:06:03.630164] W [defaults.c:2212:default_releasedir]
> (-->/usr/lib64/glusterfs/3.7.6/xlator/protocol/client.so(client_local_wipe-0x42d64)
> [0x3fff86c9bc5c] -->/usr/lib64/libglusterfs.so.0(fd_unref-0x7ba98)
> [0x3fff8abb7ad0] -->/usr/lib64/libglusterfs.so.0(default_releasedir-0x9d6d8)
> [0x3fff8ab93c58] ) 0-fuse: xlator does not implement releasedir_cbk
> [2016-10-31 04:06:03.630367] E [rpc-clnt.c:362:saved_frames_unwind] (-->
> /usr/lib64/libglusterfs.so.0(_gf_log_callingfn-0xb5c80)[0x3fff8ab79f58] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_unwind-0x1b7a0)[0x3fff8ab1dc90] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_destroy-0x1b638)[0x3fff8ab1de10] (-->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_connection_cleanup-0x19af8)[0x3fff8ab1fb18]
> (--> /usr/lib64/libgfrpc.so.0(rpc_clnt_notify-0x18e68)[0x3fff8ab20808] )))))
> 0-c_glusterfs-client-9: forced unwinding frame type(GlusterFS 3.3)
> op(LOOKUP(27)) called at 2016-10-31 04:06:03.625675 (xid=0x7f5c)
> [2016-10-31 04:06:03.630368] W [MSGID: 114031]
> [client-rpc-fops.c:1569:client3_3_fstat_cbk] 0-c_glusterfs-client-9: remote
> operation failed [Transport endpoint is not connected]
> [2016-10-31 04:06:03.630497] W [MSGID: 114031]
> [client-rpc-fops.c:2971:client3_3_lookup_cbk] 0-c_glusterfs-client-9: remote
> operation failed. Path: /configuration/oamrdncy.cfg
> (200b0bb2-d903-4924-b025-262d805c0f2f) [Transport endpoint is not connected]
> [2016-10-31 04:06:03.630871] I [MSGID: 114057]
> [client-handshake.c:1437:select_server_supported_programs]
> 0-c_glusterfs-client-9: Using Program GlusterFS 3.3, Num (1298437), Version
> (330)
>
> [2016-10-31 04:06:03.631488] I [MSGID: 114046]
> [client-handshake.c:1213:client_setvolume_cbk] 0-c_glusterfs-client-9:
> Connected to c_glusterfs-client-9, attached to remote volume
> '/opt/lvmdir/c2/brick'.
>
> [2016-10-31 04:06:03.631523] I [MSGID: 114047]
> [client-handshake.c:1224:client_setvolume_cbk] 0-c_glusterfs-client-9:
> Server and Client lk-version numbers are not same, reopening the fds
> [2016-10-31 04:06:03.631555] I [MSGID: 114042]
> [client-handshake.c:1056:client_post_handshake] 0-c_glusterfs-client-9: 6
> fds open - Delaying child_up until they are re-opened
> [2016-10-31 04:06:03.631475] W [MSGID: 114031]
> [client-rpc-fops.c:2971:client3_3_lookup_cbk] 0-c_glusterfs-client-9: remote
> operation failed. Path: /configuration/ethmac.cfg
> (00000000-0000-0000-0000-000000000000) [Transport endpoint is not connected]
> [2016-10-31 04:06:03.632256] I [MSGID: 114060]
> [client-handshake.c:820:client3_3_reopendir_cbk] 0-c_glusterfs-client-9:
> reopendir on <gfid:00000000-0000-0000-0000-000000000001> succeeded (fd = 1)
> [2016-10-31 04:06:03.632728] I [MSGID: 114060]
> [client-handshake.c:820:client3_3_reopendir_cbk] 0-c_glusterfs-client-9:
> reopendir on <gfid:257add5a-9b87-4014-8a3a-09dd0a699eec> succeeded (fd = 2)
> [2016-10-31 04:06:03.632790] I [MSGID: 114060]
> [client-handshake.c:820:client3_3_reopendir_cbk] 0-c_glusterfs-client-9:
> reopendir on <gfid:6fd47fe9-a566-47c7-8df7-e7a5e379101f> succeeded (fd = 3)
> [2016-10-31 04:06:03.632847] I [MSGID: 114060]
> [client-handshake.c:820:client3_3_reopendir_cbk] 0-c_glusterfs-client-9:
> reopendir on <gfid:fa866805-ab22-4afe-8acb-528d15ce4117> succeeded (fd = 4)
> [2016-10-31 04:06:03.632905] I [MSGID: 114060]
> [client-handshake.c:820:client3_3_reopendir_cbk] 0-c_glusterfs-client-9:
> reopendir on <gfid:139f5034-5b42-4fb8-9372-6dd7cac1e674> succeeded (fd = 5)
> [2016-10-31 04:06:03.632935] I [MSGID: 114041]
> [client-handshake.c:678:client_child_up_reopen_done] 0-c_glusterfs-client-9:
> last fd open'd/lock-self-heal'd - notifying CHILD-UP
>
> [2016-10-31 04:06:03.633028] I [MSGID: 108005]
> [afr-common.c:3841:afr_notify] 0-c_glusterfs-replicate-0: Subvolume
> 'c_glusterfs-client-9' came back up; going online.
>
> [2016-10-31 04:06:03.633386] I [MSGID: 114035]
> [client-handshake.c:193:client_set_lk_version_cbk] 0-c_glusterfs-client-9:
> Server lk version = 1
> [2016-10-31 04:06:03.634579] W [fuse-bridge.c:758:fuse_attr_cbk]
> 0-glusterfs-fuse: 20795: FSTAT() /configuration/oamrdncy.cfg => -1
> (Transport endpoint is not connected)
> [2016-10-31 04:06:03.634889] E [rpc-clnt.c:362:saved_frames_unwind] (-->
> /usr/lib64/libglusterfs.so.0(_gf_log_callingfn-0xb5c80)[0x3fff8ab79f58] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_unwind-0x1b7a0)[0x3fff8ab1dc90] (-->
> /usr/lib64/libgfrpc.so.0(saved_frames_destroy-0x1b638)[0x3fff8ab1de10] (-->
> /usr/lib64/libgfrpc.so.0(rpc_clnt_connection_cleanup-0x19af8)[0x3fff8ab1fb18]
> (--> /usr/lib64/libgfrpc.so.0(rpc_clnt_notify-0x18e68)[0x3fff8ab20808] )))))
> 0-c_glusterfs-client-9: forced unwinding frame type(GlusterFS 3.3)
> op(XATTROP(33)) called at 2016-10-31 04:06:03.625716 (xid=0x7f5d)
> [2016-10-31 04:06:03.634950] W [MSGID: 114031]
> [client-rpc-fops.c:1845:client3_3_xattrop_cbk] 0-c_glusterfs-client-9:
> remote operation failed. Path: /configuration/oamrdncy.cfg
> (200b0bb2-d903-4924-b025-262d805c0f2f)
> [2016-10-31 04:06:03.635134] W [MSGID: 108008]
> [afr-read-txn.c:250:afr_read_txn] 0-c_glusterfs-replicate-0: Unreadable
> subvolume -1 found with event generation 3 for gfid
> 200b0bb2-d903-4924-b025-262d805c0f2f. (Possible split-brain)
> [2016-10-31 04:06:03.635364] I [MSGID: 114018]
> [client.c:2042:client_rpc_notify] 0-c_glusterfs-client-9: disconnected from
> c_glusterfs-client-9. Client process will keep trying to connect to glusterd
> until brick's port is available
> [2016-10-31 04:06:03.635420] E [MSGID: 108006]
> [afr-common.c:3880:afr_notify] 0-c_glusterfs-replicate-0: All subvolumes are
> down. Going offline until atleast one of them comes back up.
> [2016-10-31 04:06:03.635762] I [MSGID: 108006]
> [afr-common.c:4008:afr_local_init] 0-c_glusterfs-replicate-0: no subvolumes
> up
> [2016-10-31 04:06:03.641160] W [fuse-bridge.c:462:fuse_entry_cbk]
> 0-glusterfs-fuse: 20808: LOOKUP() /license => -1 (Transport endpoint is not
> connected)
> The message "I [MSGID: 108006] [afr-common.c:4008:afr_local_init]
> 0-c_glusterfs-replicate-0: no subvolumes up" repeated 6 times between
> [2016-10-31 04:06:03.640564] and [2016-10-31 04:06:03.641444]
> [2016-10-31 04:06:03.641484] E [MSGID: 114031]
> [client-rpc-fops.c:1621:client3_3_inodelk_cbk] 0-c_glusterfs-client-9:
> remote operation failed [Invalid argument]
> [2016-10-31 04:06:03.641562] I [MSGID: 108006]
> [afr-common.c:4008:afr_local_init] 0-c_glusterfs-replicate-0: no subvolumes
> up
> [2016-10-31 04:06:03.641573] E [MSGID: 108010]
> [afr-lk-common.c:665:afr_unlock_inodelk_cbk] 0-c_glusterfs-replicate-0:
> path=/configuration/oamrdncy.cfg gfid=200b0bb2-d903-4924-b025-262d805c0f2f:
> unlock failed on subvolume c_glusterfs-client-9 with lock owner
> 6cd0c189ff3f0000 [Invalid argument]
> [2016-10-31 04:06:03.641655] I [MSGID: 108006]
> [afr-common.c:4008:afr_local_init] 0-c_glusterfs-replicate-0: no subvolumes
> up
> [2016-10-31 04:06:03.641716] W [fuse-bridge.c:462:fuse_entry_cbk]
> 0-glusterfs-fuse: 20809: LOOKUP() /lost+found => -1 (Transport endpoint is
> not connected)
> [2016-10-31 04:06:03.642387] W [fuse-bridge.c:462:fuse_entry_cbk]
> 0-glusterfs-fuse: 20813: LOOKUP() /lost+found => -1 (Transport endpoint is
> not connected)
> ...
>
> Analysis
>
> I think the disconnection and reconnectiong between client(glusterfs on A
> board) and server(glusterfsd on A board) has a race condition as below.
>
>
> process 1
> process 2
>
> [2016-10-31 04:06:03.626047]                                        readv
> err show that
>
> the disconnect happen
>
> between client and server.
>
> [2016-10-31 04:06:03.627345]                                        It will
> call rpc_clnt_notify().
>
> conn->connected = 0 in
>
> rpc_clnt_connection_cleanup.
>
> Creating a timer which will
>
> reconnect after 10 second.
>
>
>
> [2016-10-31 04:06:03.628381]
> calling rpc_clnt_submit().
>
> it will call rpc_transport_connect
>
> because conn->connected is 0.
>
> [2016-10-31 04:06:03.631488]
> the new connection has been successful.
>
>
> [2016-10-31 04:06:03.633028]
> calling  afr_notify(). In the case
>
> GF_EVENT_CHILD_UP  the new
>
> new connection is set by "priv->child_up[idx] = 1"
>
>
> [2016-10-31 04:06:03.635364]                                      continue
> to run client_rpc_notify()
>
> will notify RPC_CLNT_DISCONNECT
>
> in case RPC_CLNT_DISCONNECT.
>
> [2016-10-31 04:06:03.635420]                                      In
> afr_notify() will set "priv->child_up[idx] = 0",
>
> which is the new connection,
>
> in the case RPC_CLNT_DISCONNECT.
>
> And the all the subvolume is down.
>
> [2016-10-31 04:06:03.635762]                                       All the
> access will be failed because
>
> no subvolumes up.And rpc_transport_connect()
>
> will not be called  because the conn->connected
>
> has been set to 1 in process  2
>
>
> Please help me to check my analysis.
>
> Thanks,
> Xin
>

Awesome! You root caused this on your own. This exact same issue was
root caused recently and we have a pending patch for it [1]. Expect
this to be fixed soon.

[1]: https://review.gluster.org/15916

>
>
>
>
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