From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: Ext4 and xfs problems in dm-thin on allocation and discard Date: Tue, 19 Jun 2012 09:30:42 -0400 Message-ID: <20120619133041.GB6811@redhat.com> References: <4FDF9EBE.2030809@shiftmail.org> <20120619015745.GJ25389@dastard> <20120619031241.GA3884@redhat.com> <20120619131649.GA6811@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org To: =?utf-8?B?THVrw6HFoQ==?= Czerner Cc: Dave Chinner , Spelic , device-mapper development , linux-ext4@vger.kernel.org, xfs@oss.sgi.com List-Id: dm-devel.ids On Tue, Jun 19 2012 at 9:25am -0400, Luk=C3=A1=C5=A1 Czerner wrote: > On Tue, 19 Jun 2012, Mike Snitzer wrote: >=20 > > Date: Tue, 19 Jun 2012 09:16:49 -0400 > > From: Mike Snitzer > > To: Luk=C3=A1=C5=A1 Czerner > > Cc: Dave Chinner , Spelic , > > device-mapper development , > > linux-ext4@vger.kernel.org, xfs@oss.sgi.com > > Subject: Re: Ext4 and xfs problems in dm-thin on allocation and dis= card > >=20 > > On Tue, Jun 19 2012 at 2:32am -0400, > > Luk=C3=A1=C5=A1 Czerner wrote: > > > > > So do I understand correctly that even though the discard came > > > through and thinp took advantage of it it still returns EOPNOTSUP= P ? > >=20 > > No, not correct. Why are you assuming this? I must be missing > > something from this discussion that led you there. >=20 > Those two paragraphs led me to that conclusion: >=20 > That message says the underlying device doesn't support discards > (because it is an MD device). But the thinp device still has disca= rds > enabled -- it just won't pass the discards down to the underlying d= ata > device. >=20 > The discards still inform the thin-pool that the corresponding exte= nts > are no longer allocated. >=20 > so I am a bit confused now. Why the dm-thin returned EOPNOTSUPP then > ? Is that because it has been configured to ignore_discard, or it > actually takes advantage of the discard but underlying device does > not support it (and no_discard_passdown is not set) so it return > EOPNOTSUPP ? >=20 > >=20 > > > This seems rather suboptimal. IIRC there was a discussion to add = an > > > option to enable/disable sending discard in thinp target down > > > to the device. > > >=20 > > > So maybe it might be a bit smarter than that and actually > > > enable/disable discard pass through depending on the underlying > > > support, so we do not blindly send discard down to the device eve= n > > > though it does not support it. > >=20 > > Yes, that is what we did. > >=20 > > Discards are enabled my default (including discard passdown), but i= f the > > underlying data device doesn't support discards then the discards w= ill > > not be passed down. > >=20 > > And here are the feature controls that can be provided when loading= the > > thin-pool's DM table: > >=20 > > ignore_discard: disable discard > > no_discard_passdown: don't pass discards down to the data device > >=20 > > -EOPNOTSUPP is only ever returned if 'ignore_discard' is provided. >=20 > Ok, so in this case 'ignore_discard' has been configured ? I don't recall Spelic saying anything about EOPNOTSUPP. So what has made you zero in on an -EOPNOTSUPP return (which should not be happening)? -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q5JDUoGa095960 for ; Tue, 19 Jun 2012 08:30:50 -0500 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id EeyD0JFEzhv3IGbC for ; Tue, 19 Jun 2012 06:30:49 -0700 (PDT) From: Mike Snitzer Date: Tue, 19 Jun 2012 09:30:42 -0400 Subject: Re: Ext4 and xfs problems in dm-thin on allocation and discard Message-ID: <20120619133041.GB6811@redhat.com> References: <4FDF9EBE.2030809@shiftmail.org> <20120619015745.GJ25389@dastard> <20120619031241.GA3884@redhat.com> <20120619131649.GA6811@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: =?utf-8?B?THVrw6HFoQ==?= Czerner Cc: device-mapper development , linux-ext4@vger.kernel.org, xfs@oss.sgi.com, Spelic T24gVHVlLCBKdW4gMTkgMjAxMiBhdCAgOToyNWFtIC0wNDAwLApMdWvDocWhIEN6ZXJuZXIgPGxj emVybmVyQHJlZGhhdC5jb20+IHdyb3RlOgoKPiBPbiBUdWUsIDE5IEp1biAyMDEyLCBNaWtlIFNu aXR6ZXIgd3JvdGU6Cj4gCj4gPiBEYXRlOiBUdWUsIDE5IEp1biAyMDEyIDA5OjE2OjQ5IC0wNDAw Cj4gPiBGcm9tOiBNaWtlIFNuaXR6ZXIgPHNuaXR6ZXJAcmVkaGF0LmNvbT4KPiA+IFRvOiBMdWvD ocWhIEN6ZXJuZXIgPGxjemVybmVyQHJlZGhhdC5jb20+Cj4gPiBDYzogRGF2ZSBDaGlubmVyIDxk YXZpZEBmcm9tb3JiaXQuY29tPiwgU3BlbGljIDxzcGVsaWNAc2hpZnRtYWlsLm9yZz4sCj4gPiAg ICAgZGV2aWNlLW1hcHBlciBkZXZlbG9wbWVudCA8ZG0tZGV2ZWxAcmVkaGF0LmNvbT4sCj4gPiAg ICAgbGludXgtZXh0NEB2Z2VyLmtlcm5lbC5vcmcsIHhmc0Bvc3Muc2dpLmNvbQo+ID4gU3ViamVj dDogUmU6IEV4dDQgYW5kIHhmcyBwcm9ibGVtcyBpbiBkbS10aGluIG9uIGFsbG9jYXRpb24gYW5k IGRpc2NhcmQKPiA+IAo+ID4gT24gVHVlLCBKdW4gMTkgMjAxMiBhdCAgMjozMmFtIC0wNDAwLAo+ ID4gTHVrw6HFoSBDemVybmVyIDxsY3plcm5lckByZWRoYXQuY29tPiB3cm90ZToKPiA+Cj4gPiA+ IFNvIGRvIEkgdW5kZXJzdGFuZCBjb3JyZWN0bHkgdGhhdCBldmVuIHRob3VnaCB0aGUgZGlzY2Fy ZCBjYW1lCj4gPiA+IHRocm91Z2ggYW5kIHRoaW5wIHRvb2sgYWR2YW50YWdlIG9mIGl0IGl0IHN0 aWxsIHJldHVybnMgRU9QTk9UU1VQUCA/Cj4gPiAKPiA+IE5vLCBub3QgY29ycmVjdC4gIFdoeSBh cmUgeW91IGFzc3VtaW5nIHRoaXM/ICBJIG11c3QgYmUgbWlzc2luZwo+ID4gc29tZXRoaW5nIGZy b20gdGhpcyBkaXNjdXNzaW9uIHRoYXQgbGVkIHlvdSB0aGVyZS4KPiAKPiBUaG9zZSB0d28gcGFy YWdyYXBocyBsZWQgbWUgdG8gdGhhdCBjb25jbHVzaW9uOgo+IAo+ICAgVGhhdCBtZXNzYWdlIHNh eXMgdGhlIHVuZGVybHlpbmcgZGV2aWNlIGRvZXNuJ3Qgc3VwcG9ydCBkaXNjYXJkcwo+ICAgKGJl Y2F1c2UgaXQgaXMgYW4gTUQgZGV2aWNlKS4gIEJ1dCB0aGUgdGhpbnAgZGV2aWNlIHN0aWxsIGhh cyBkaXNjYXJkcwo+ICAgZW5hYmxlZCAtLSBpdCBqdXN0IHdvbid0IHBhc3MgdGhlIGRpc2NhcmRz IGRvd24gdG8gdGhlIHVuZGVybHlpbmcgZGF0YQo+ICAgZGV2aWNlLgo+IAo+ICAgVGhlIGRpc2Nh cmRzIHN0aWxsIGluZm9ybSB0aGUgdGhpbi1wb29sIHRoYXQgdGhlIGNvcnJlc3BvbmRpbmcgZXh0 ZW50cwo+ICAgYXJlIG5vIGxvbmdlciBhbGxvY2F0ZWQuCj4gCj4gc28gSSBhbSBhIGJpdCBjb25m dXNlZCBub3cuIFdoeSB0aGUgZG0tdGhpbiByZXR1cm5lZCBFT1BOT1RTVVBQIHRoZW4KPiA/IElz IHRoYXQgYmVjYXVzZSBpdCBoYXMgYmVlbiBjb25maWd1cmVkIHRvIGlnbm9yZV9kaXNjYXJkLCBv ciBpdAo+IGFjdHVhbGx5IHRha2VzIGFkdmFudGFnZSBvZiB0aGUgZGlzY2FyZCBidXQgdW5kZXJs eWluZyBkZXZpY2UgZG9lcwo+IG5vdCBzdXBwb3J0IGl0IChhbmQgbm9fZGlzY2FyZF9wYXNzZG93 biBpcyBub3Qgc2V0KSBzbyBpdCByZXR1cm4KPiBFT1BOT1RTVVBQID8KPiAKPiA+IAo+ID4gPiBU aGlzIHNlZW1zIHJhdGhlciBzdWJvcHRpbWFsLiBJSVJDIHRoZXJlIHdhcyBhIGRpc2N1c3Npb24g dG8gYWRkIGFuCj4gPiA+IG9wdGlvbiB0byBlbmFibGUvZGlzYWJsZSBzZW5kaW5nIGRpc2NhcmQg aW4gdGhpbnAgdGFyZ2V0IGRvd24KPiA+ID4gdG8gdGhlIGRldmljZS4KPiA+ID4gCj4gPiA+IFNv IG1heWJlIGl0IG1pZ2h0IGJlIGEgYml0IHNtYXJ0ZXIgdGhhbiB0aGF0IGFuZCBhY3R1YWxseQo+ ID4gPiBlbmFibGUvZGlzYWJsZSBkaXNjYXJkIHBhc3MgdGhyb3VnaCBkZXBlbmRpbmcgb24gdGhl IHVuZGVybHlpbmcKPiA+ID4gc3VwcG9ydCwgc28gd2UgZG8gbm90IGJsaW5kbHkgc2VuZCBkaXNj YXJkIGRvd24gdG8gdGhlIGRldmljZSBldmVuCj4gPiA+IHRob3VnaCBpdCBkb2VzIG5vdCBzdXBw b3J0IGl0Lgo+ID4gCj4gPiBZZXMsIHRoYXQgaXMgd2hhdCB3ZSBkaWQuCj4gPiAKPiA+IERpc2Nh cmRzIGFyZSBlbmFibGVkIG15IGRlZmF1bHQgKGluY2x1ZGluZyBkaXNjYXJkIHBhc3Nkb3duKSwg YnV0IGlmIHRoZQo+ID4gdW5kZXJseWluZyBkYXRhIGRldmljZSBkb2Vzbid0IHN1cHBvcnQgZGlz Y2FyZHMgdGhlbiB0aGUgZGlzY2FyZHMgd2lsbAo+ID4gbm90IGJlIHBhc3NlZCBkb3duLgo+ID4g Cj4gPiBBbmQgaGVyZSBhcmUgdGhlIGZlYXR1cmUgY29udHJvbHMgdGhhdCBjYW4gYmUgcHJvdmlk ZWQgd2hlbiBsb2FkaW5nIHRoZQo+ID4gdGhpbi1wb29sJ3MgRE0gdGFibGU6Cj4gPiAKPiA+IGln bm9yZV9kaXNjYXJkOiBkaXNhYmxlIGRpc2NhcmQKPiA+IG5vX2Rpc2NhcmRfcGFzc2Rvd246IGRv bid0IHBhc3MgZGlzY2FyZHMgZG93biB0byB0aGUgZGF0YSBkZXZpY2UKPiA+IAo+ID4gLUVPUE5P VFNVUFAgaXMgb25seSBldmVyIHJldHVybmVkIGlmICdpZ25vcmVfZGlzY2FyZCcgaXMgcHJvdmlk ZWQuCj4gCj4gT2ssIHNvIGluIHRoaXMgY2FzZSAnaWdub3JlX2Rpc2NhcmQnIGhhcyBiZWVuIGNv bmZpZ3VyZWQgPwoKSSBkb24ndCByZWNhbGwgU3BlbGljIHNheWluZyBhbnl0aGluZyBhYm91dCBF T1BOT1RTVVBQLiAgU28gd2hhdCBoYXMKbWFkZSB5b3UgemVybyBpbiBvbiBhbiAtRU9QTk9UU1VQ UCByZXR1cm4gKHdoaWNoIHNob3VsZCBub3QgYmUKaGFwcGVuaW5nKT8KCl9fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCnhmcyBtYWlsaW5nIGxpc3QKeGZzQG9z cy5zZ2kuY29tCmh0dHA6Ly9vc3Muc2dpLmNvbS9tYWlsbWFuL2xpc3RpbmZvL3hmcwo=