This is probably a question to IEFT working group, but anyway. If my layout has a flag 'return-on-close' and open state id is not valid any more should client expect layout to be still valid? Tigran. ----- Original Message ----- > From: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx> > To: "Weston Andros Adamson" <dros@xxxxxxxxxx> > Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>, "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Steve Dickson" > <steved@xxxxxxxxxx> > Sent: Thursday, October 10, 2013 4:48:52 PM > Subject: Re: DoS with NFSv4.1 client > > > > ----- Original Message ----- > > From: "Weston Andros Adamson" <dros@xxxxxxxxxx> > > To: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx> > > Cc: "<linux-nfs@xxxxxxxxxxxxxxx>" <linux-nfs@xxxxxxxxxxxxxxx>, "Andy > > Adamson" <William.Adamson@xxxxxxxxxx>, "Steve > > Dickson" <steved@xxxxxxxxxx> > > Sent: Thursday, October 10, 2013 4:35:25 PM > > Subject: Re: DoS with NFSv4.1 client > > > > Well, it'd be nice not to loop forever, but my question remains, is this > > due > > to a server bug (the DS not knowing about new stateid from MDS)? > > > > Up to now, we have pushed open state id to the DS only on LAYOUTGET. > This have to be changed, as the behaviour is not spec compliant. > > Tigran. > > > -dros > > > > On Oct 10, 2013, at 10:14 AM, Weston Andros Adamson <dros@xxxxxxxxxx> > > wrote: > > > > > So is this a server bug? It seems like the client is behaving > > > correctly... > > > > > > -dros > > > > > > On Oct 10, 2013, at 5:56 AM, "Mkrtchyan, Tigran" > > > <tigran.mkrtchyan@xxxxxxx> > > > wrote: > > > > > >> > > >> > > >> Today we was 'luck' to have such situation at day time. > > >> Here is what happens: > > >> > > >> The client sends an OPEN and gets an open state id. > > >> This is followed by LAYOUTGET ... and READ to DS. > > >> At some point, server returns back BAD_STATEID. > > >> This triggers client to issue a new OPEN and use > > >> new open stateid with READ request to DS. As new > > >> stateid is not known to DS, it keeps returning > > >> BAD_STATEID and becomes an infinite loop. > > >> > > >> Regards, > > >> Tigran. > > >> > > >> > > >> > > >> ----- Original Message ----- > > >>> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx> > > >>> To: linux-nfs@xxxxxxxxxxxxxxx > > >>> Cc: "Andy Adamson" <william.adamson@xxxxxxxxxx>, "Steve Dickson" > > >>> <steved@xxxxxxxxxx> > > >>> Sent: Wednesday, October 9, 2013 10:48:32 PM > > >>> Subject: DoS with NFSv4.1 client > > >>> > > >>> > > >>> Hi, > > >>> > > >>> last night we got a DoS attack with one of the NFS clients. > > >>> The farm node, which was accessing data with pNFS, > > >>> went mad and have tried to kill dCache NFS server. As usually > > >>> this have happened over night and we was not able to > > >>> get a network traffic or bump the debug level. > > >>> > > >>> The symptoms are: > > >>> > > >>> client starts to bombard the MDS with OPEN requests. As we see > > >>> state created on the server side, the requests was processed by > > >>> server. Nevertheless, for some reason, client did not like it. Here > > >>> is the result of mountstats: > > >>> > > >>> OPEN: > > >>> 17087065 ops (99%) 1 retrans (0%) 0 major timeouts > > >>> avg bytes sent per op: 356 avg bytes received per op: 455 > > >>> backlog wait: 0.014707 RTT: 4.535704 total execute time: 4.574094 > > >>> (milliseconds) > > >>> CLOSE: > > >>> 290 ops (0%) 0 retrans (0%) 0 major timeouts > > >>> avg bytes sent per op: 247 avg bytes received per op: 173 > > >>> backlog wait: 308.827586 RTT: 1748.479310 total execute time: > > >>> 2057.365517 > > >>> (milliseconds) > > >>> > > >>> > > >>> As you can see there is a quite a big difference between number of open > > >>> and > > >>> close requests. > > >>> The same picture we can see on the server side as well: > > >>> > > >>> NFSServerV41 Stats: average±stderr(ns) min(ns) > > >>> max(ns) Sampes > > >>> DESTROY_SESSION 26056±4511.89 13000 > > >>> 97000 17 > > >>> OPEN 1197297± 0.00 816000 > > >>> 31924558000 54398533 > > >>> RESTOREFH 0± 0.00 0 > > >>> 25018778000 54398533 > > >>> SEQUENCE 1000± 0.00 1000 > > >>> 26066722000 55601046 > > >>> LOOKUP 4607959± 0.00 375000 > > >>> 26977455000 32118 > > >>> GETDEVICEINFO 13158±100.88 4000 > > >>> 655000 11378 > > >>> CLOSE 16236211± 0.00 5000 > > >>> 21021819000 20420 > > >>> LAYOUTGET 271736361± 0.00 10003000 > > >>> 68414723000 21095 > > >>> > > >>> The last column is the number of requests. > > >>> > > >>> This is with RHEL6.4 as the client. By looking at the code, > > >>> I can see a loop at nfs4proc.c#nfs4_do_open() which can be > > >>> the cause of the problem. Nevertheless, I can't > > >>> fine any reason why this look turned into an 'infinite' one. > > >>> > > >>> At the and our server ran out of memory and we have returned > > >>> NFSERR_SERVERFAULT to the client. This triggered client to > > >>> reestablish the session and all open state ids was > > >>> invalidated and cleaned up. > > >>> > > >>> I am still trying to reproduce this behavior (on client > > >>> and server) and any hint is welcome. > > >>> > > >>> Tigran. > > >>> -- > > >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > >>> the body of a message to majordomo@xxxxxxxxxxxxxxx > > >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >>> > > >> -- > > >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
