[Bugs] [Bug 1331502] New: Under high read load, sometimes the message "XDR decoding failed" appears in the logs and read fails
bugzilla at redhat.com
bugzilla at redhat.com
Thu Apr 28 17:05:09 UTC 2016
https://bugzilla.redhat.com/show_bug.cgi?id=1331502
Bug ID: 1331502
Summary: Under high read load, sometimes the message "XDR
decoding failed" appears in the logs and read fails
Product: GlusterFS
Version: 3.7.11
Component: rpc
Assignee: bugs at gluster.org
Reporter: xhernandez at datalab.es
CC: bugs at gluster.org
Description of problem:
Under some circumstances, the following errors appear in the logs:
[2016-04-28 16:48:58.710106] E [MSGID: 114030]
[client-rpc-fops.c:3022:client3_3_readv_cbk] 0-test-client-2: XDR decoding
failed [Invalid argument]
[2016-04-28 16:48:58.710223] W [MSGID: 114031]
[client-rpc-fops.c:3050:client3_3_readv_cbk] 0-test-client-2: remote operation
failed [Invalid argument]
This causes the read to fail.
Apparently there are no problems in the bricks.
Version-Release number of selected component (if applicable): 3.7.11
How reproducible:
It appears randomly but quite consistently with the following steps.
Steps to Reproduce:
1. create a distributed-disperse 4*(4+2) volume
2. export it with ganesha using gfapi
3. mount it from another machine using NFSv4
4. iozone -t2 -s10g -r1024k -i0 -w -F <mount>/iozone{1..2}.dat
5. echo 3 >/proc/sys/vm/drop_caches
6. iozone -t2 -s10g -r1024k -i1 -w -F <mount>/iozone{1..2}.dat
Generally the problem appears soon after the step 6 begins.
Actual results:
The iozone read test fails.
Expected results:
The iozone test should complete successfully.
Additional info:
This seems caused by an incorrect handling of incoming TCP data. This info is
at the moment that the error happens:
Breakpoint 1, client3_3_readv_cbk (req=0x7f540e64106c, iov=0x7f540e6410ac,
count=<optimized out>, myframe=0x7f54259a4d54) at client-rpc-fops.c:3021
3021 gf_msg (this->name, GF_LOG_ERROR, EINVAL,
(gdb) print *iov
$1 = {iov_base = 0x7f53e994e018, iov_len = 116}
(gdb) x/116xb 0x7f53e994e018
0x7f53e994e018: 0x00 0x00 0x80 0x00 0x00 0x00 0x00 0x00
0x7f53e994e020: 0xa8 0xbf 0xa3 0xe0 0x5f 0x48 0x4c 0x1e
0x7f53e994e028: 0x80 0xa3 0x8a 0xd8 0x9d 0xa1 0x1c 0x75
0x7f53e994e030: 0x80 0xa3 0x8a 0xd8 0x9d 0xa1 0x1c 0x75
0x7f53e994e038: 0x00 0x00 0x00 0x00 0x00 0x00 0x08 0x00
0x7f53e994e040: 0x00 0x00 0x81 0xa0 0x00 0x00 0x00 0x01
0x7f53e994e048: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x7f53e994e050: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x7f53e994e058: 0x00 0x00 0x00 0x00 0xa0 0x00 0x00 0x00
0x7f53e994e060: 0x00 0x00 0x10 0x00 0x00 0x00 0x00 0x00
0x7f53e994e068: 0x00 0x50 0x00 0x00 0x57 0x22 0x04 0x1f
0x7f53e994e070: 0x25 0x38 0x92 0x91 0x57 0x22 0x04 0xb3
0x7f53e994e078: 0x03 0x53 0x1b 0x13 0x57 0x22 0x04 0xb3
0x7f53e994e080: 0x06 0xf5 0xe1 0x99 0x00 0x00 0x80 0x00
0x7f53e994e088: 0x00 0x00 0x00 0x26
(gdb) x/154xb 0x7f53e994e018
0x7f53e994e018: 0x00 0x00 0x80 0x00 0x00 0x00 0x00 0x00
0x7f53e994e020: 0xa8 0xbf 0xa3 0xe0 0x5f 0x48 0x4c 0x1e
0x7f53e994e028: 0x80 0xa3 0x8a 0xd8 0x9d 0xa1 0x1c 0x75
0x7f53e994e030: 0x80 0xa3 0x8a 0xd8 0x9d 0xa1 0x1c 0x75
0x7f53e994e038: 0x00 0x00 0x00 0x00 0x00 0x00 0x08 0x00
0x7f53e994e040: 0x00 0x00 0x81 0xa0 0x00 0x00 0x00 0x01
0x7f53e994e048: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x7f53e994e050: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x7f53e994e058: 0x00 0x00 0x00 0x00 0xa0 0x00 0x00 0x00
0x7f53e994e060: 0x00 0x00 0x10 0x00 0x00 0x00 0x00 0x00
0x7f53e994e068: 0x00 0x50 0x00 0x00 0x57 0x22 0x04 0x1f
0x7f53e994e070: 0x25 0x38 0x92 0x91 0x57 0x22 0x04 0xb3
0x7f53e994e078: 0x03 0x53 0x1b 0x13 0x57 0x22 0x04 0xb3
0x7f53e994e080: 0x06 0xf5 0xe1 0x99 0x00 0x00 0x80 0x00
0x7f53e994e088: 0x00 0x00 0x00 0x26 0x00 0x00 0x00 0x01
0x7f53e994e090: 0x00 0x00 0x00 0x17 0x00 0x00 0x00 0x02
0x7f53e994e098: 0x67 0x6c 0x75 0x73 0x74 0x65 0x72 0x66
0x7f53e994e0a0: 0x73 0x2e 0x69 0x6e 0x6f 0x64 0x65 0x6c
0x7f53e994e0a8: 0x6b 0x2d 0x63 0x6f 0x75 0x6e 0x74 0x00
0x7f53e994e0b0: 0x31 0x00
(gdb) bt
#0 client3_3_readv_cbk (req=0x7f540e64106c, iov=0x7f540e6410ac,
count=<optimized out>, myframe=0x7f54259a4d54) at client-rpc-fops.c:3021
#1 0x00007f542a677ab0 in rpc_clnt_handle_reply
(clnt=clnt at entry=0x7f54101cdef0, pollin=pollin at entry=0x7f54000091f0) at
rpc-clnt.c:764
#2 0x00007f542a677d6f in rpc_clnt_notify (trans=<optimized out>,
mydata=0x7f54101cdf20, event=<optimized out>, data=0x7f54000091f0) at
rpc-clnt.c:925
#3 0x00007f542a673853 in rpc_transport_notify (this=this at entry=0x7f54101ddb70,
event=event at entry=RPC_TRANSPORT_MSG_RECEIVED, data=data at entry=0x7f54000091f0)
at rpc-transport.c:546
#4 0x00007f541d881666 in socket_event_poll_in (this=this at entry=0x7f54101ddb70)
at socket.c:2237
#5 0x00007f541d8842c4 in socket_event_handler (fd=fd at entry=30,
idx=idx at entry=20, data=0x7f54101ddb70, poll_in=1, poll_out=0, poll_err=0) at
socket.c:2350
#6 0x00007f542a90aa4a in event_dispatch_epoll_handler (event=0x7f540effc540,
event_pool=0xd3d9a0) at event-epoll.c:575
#7 event_dispatch_epoll_worker (data=0x7f54100d0890) at event-epoll.c:678
#8 0x00007f542d0fbdc5 in start_thread () from /lib64/libpthread.so.0
#9 0x00007f542c7bc28d in clone () from /lib64/libc.so.6
The fragment to decode has 116 bytes, but it should have 154 bytes (otherwise
the xdata encoded is cut). I have verified that the remaining 38 bytes are
stored in the beggining of the second iovec entry (iov[1]).
A network capture of this exact packet reveals the following data:
Frame 334067: 53754 bytes on wire (430032 bits), 53754 bytes captured (430032
bits)
Encapsulation type: Ethernet (1)
Arrival Time: Apr 28, 2016 18:00:47.706023000 Hora de verano romance
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1461859247.706023000 seconds
[Time delta from previous captured frame: 0.000130000 seconds]
[Time delta from previous displayed frame: 0.002272000 seconds]
[Time since reference or first frame: 5.865347000 seconds]
Frame Number: 334067
Frame Length: 53754 bytes (430032 bits)
Capture Length: 53754 bytes (430032 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ip:tcp:rpc:glusterfs:data:rpc]
Ethernet II, Src: 00:1b:21:91:aa:30, Dst: 00:1b:21:91:aa:17
Destination: 00:1b:21:91:aa:17
Address: 00:1b:21:91:aa:17
.... ..0. .... .... .... .... = LG bit: Globally unique address
(factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Source: 00:1b:21:91:aa:30
Address: 00:1b:21:91:aa:30
.... ..0. .... .... .... .... = LG bit: Globally unique address
(factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 193.109.174.232, Dst: 193.109.174.230
0100 .... = Version: 4
.... 0101 = Header Length: 20 bytes
Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
0000 00.. = Differentiated Services Codepoint: Default (0)
.... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport
(0)
Total Length: 53740
Identification: 0x517a (20858)
Flags: 0x02 (Don't Fragment)
0... .... = Reserved bit: Not set
.1.. .... = Don't fragment: Set
..0. .... = More fragments: Not set
Fragment offset: 0
Time to live: 64
Protocol: TCP (6)
Header checksum: 0x36e7 [validation disabled]
[Good: False]
[Bad: False]
Source: 193.109.174.232
Destination: 193.109.174.230
[Source GeoIP: Unknown]
[Destination GeoIP: Unknown]
Transmission Control Protocol, Src Port: 49152 (49152), Dst Port: 65205
(65205), Seq: 383891321, Ack: 1959945, Len: 53688
Source Port: 49152
Destination Port: 65205
[Stream index: 11]
[TCP Segment Len: 53688]
Sequence number: 383891321 (relative sequence number)
[Next sequence number: 383945009 (relative sequence number)]
Acknowledgment number: 1959945 (relative ack number)
Header Length: 32 bytes
Flags: 0x010 (ACK)
000. .... .... = Reserved: Not set
...0 .... .... = Nonce: Not set
.... 0... .... = Congestion Window Reduced (CWR): Not set
.... .0.. .... = ECN-Echo: Not set
.... ..0. .... = Urgent: Not set
.... ...1 .... = Acknowledgment: Set
.... .... 0... = Push: Not set
.... .... .0.. = Reset: Not set
.... .... ..0. = Syn: Not set
.... .... ...0 = Fin: Not set
[TCP Flags: *******A****]
Window size value: 17518
[Calculated window size: 17518]
[Window size scaling factor: -1 (unknown)]
Checksum: 0xb289 [validation disabled]
[Good Checksum: False]
[Bad Checksum: False]
Urgent pointer: 0
Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps
No-Operation (NOP)
Type: 1
0... .... = Copy on fragmentation: No
.00. .... = Class: Control (0)
...0 0001 = Number: No-Operation (NOP) (1)
No-Operation (NOP)
Type: 1
0... .... = Copy on fragmentation: No
.00. .... = Class: Control (0)
...0 0001 = Number: No-Operation (NOP) (1)
Timestamps: TSval 192225006, TSecr 192258004
Kind: Time Stamp Option (8)
Length: 10
Timestamp value: 192225006
Timestamp echo reply: 192258004
[SEQ/ACK analysis]
[Bytes in flight: 53688]
TCP segment data (32836 bytes)
TCP segment data (20852 bytes)
[2 Reassembled TCP Segments (32952 bytes): #334064(116), #334067(32836)]
[Frame: 334064, payload: 0-115 (116 bytes)]
[Frame: 334067, payload: 116-32951 (32836 bytes)]
[Segment count: 2]
[Reassembled TCP length: 32952]
[Reassembled TCP Data: 800080b40000896800000001000000000000000000000000...]
Remote Procedure Call, Type:Reply XID:0x00008968
Fragment header: Last fragment, 32948 bytes
1... .... .... .... .... .... .... .... = Last Fragment: Yes
.000 0000 0000 0000 1000 0000 1011 0100 = Fragment Length: 32948
XID: 0x00008968 (35176)
Message Type: Reply (1)
[Program: GlusterFS (1298437)]
[Program Version: 330]
[Procedure: READ (12)]
Reply State: accepted (0)
[This is a reply to a request in frame 333872]
[Time from request: 0.002272000 seconds]
Verifier
Flavor: AUTH_NULL (0)
Length: 0
Accept State: RPC executed successfully (0)
GlusterFS
[Program Version: 330]
[GlusterFS: READ (12)]
Return value: 32768
Errno: 0 (No error)
IATT
GFID: c38e35f0-31a1-4501-8a21-064b084c59df
Inode: 9953243570797042143
Device: 0x0000000000000800
Mode: 0100640, S_IRUSR, S_IWUSR, S_IRGRP
.... .... .... .... .... 0... .... .... = S_ISUID: Not set
.... .... .... .... .... .0.. .... .... = S_ISGID: Not set
.... .... .... .... .... ..0. .... .... = S_ISVTX: Not set
.... .... .... .... .... ...1 .... .... = S_IRUSR: Set
.... .... .... .... .... .... 1... .... = S_IWUSR: Set
.... .... .... .... .... .... .0.. .... = S_IXUSR: Not set
.... .... .... .... .... .... ..1. .... = S_IRGRP: Set
.... .... .... .... .... .... ...0 .... = S_IWGRP: Not set
.... .... .... .... .... .... .... 0... = S_IXGRP: Not set
.... .... .... .... .... .... .... .0.. = S_IROTH: Not set
.... .... .... .... .... .... .... ..0. = S_IWOTH: Not set
.... .... .... .... .... .... .... ...0 = S_IXOTH: Not set
Number of hard links: 1
UID: 0
GID: 0
Root device: 0x0000000000000000
Size: 2684354560
Block size: 4096
Blocks: 5242880
Time of last access: Apr 28, 2016 17:58:23.604815960 Hora de verano
romance
Time of last modification: Apr 28, 2016 18:00:33.873544532 Hora de
verano romance
Time of last status change: Apr 28, 2016 18:00:33.874544506 Hora de
verano romance
Size: 32768
Dict, contains 1 item
[Size: 38 (40 bytes inc. RPC-roundup)]
Items: 1
glusterfs.inodelk-count: 1
[RPC-roundup bytes:
00005c5c5c5c5c5c5c5c0000000000000000000000000000...]
Data (32768 bytes)
<raw data stripped>
Data: 5c5c5c5c5c5c5c5c00000000000000000000000000000000...
[Length: 32768]
We can see the answer has been reassembled from 2 TCP segments, the first one
being of 116 bytes. Probably this is the cause of the problem.
Maybe the XDR decoding should make use of additional data in the second iovec
entry if needed ?
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