From mboxrd@z Thu Jan 1 00:00:00 1970 From: "=?utf-8?B?Wmhlbmd5dWFuIExpdQ==?=" Subject: Re: [PATCH] md/raid5: write an empty meta-block when creatinglogsuper-block Date: Thu, 27 Oct 2016 22:05:06 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Sender: linux-raid-owner@vger.kernel.org To: =?utf-8?B?U2hhb2h1YSBMaQ==?= Cc: =?utf-8?B?U29uZyBMaXU=?= , =?utf-8?B?bGludXgtcmFpZA==?= , =?utf-8?B?bGl1emhlbmd5dWFuZzUyMQ==?= List-Id: linux-raid.ids U29ycnkgZm9yIHRoZSB1bmNsZWFyIGV4cHJlc3Npb24uDQoNClRoZSBsb2cgbWlnaHQgbG9v ayBsaWtlIHRoaXMgYmVmb3JlIHdlIGRpZCBhIHJlY292ZXJ5IDoNCnwgbWIxIHwgbWIyIHwg bWIzICB8ICAgICAgICAgICB8ICAgICAgICAgICAgfCAgICAgICAgICAgfCANCiBsYXN0X2No ZWNrcG9pbnQgPSBtYjEncG9zdGlvbiwgICAgbGFzdF9jcF9zZXEgPSBtYjEnc2VxDQpBZnRl ciB3ZSBkaWQgYSByZWNvdmVyeSh3ZSB3b3VsZCB3cml0ZSBhIGVtcHR5IG1ldGEgYmxvY2sg ZW1iIGF0IGxvZyB0YWlsKToNCnwgbWIxIHwgbWIyIHwgbWIzIHwgIGVtYiB8ICAgICAgICAg ICAgfCAgICAgICAgICAgfCANCmxhc3RfY2hlY2twb2ludCA9IGVtYidwb3NpdGlvbiwgIGxh c3RfY3Bfc2VxID0gbWIxJ3NlcSArIDExDQpUaGVuIHdlIHdyaXRlIHR3byBtZXRhIGJsb2Nr cyBhbmQgc3VwcG9zZSBjcmFzaCBoYXBwZW5zOg0KfCBtYjEgfCBtYjIgfCBtYjMgfCAgZW1i IHwgIG1iNCB8IG1iNSB8IA0KbGFzdF9jaGVja3BvaW50ID0gZW1iJ3Bvc2l0aW9uLCAgbGFz dF9jcF9zZXEgPSBtYjEnc2VxICsgMTENCk5vdyB3ZSBkaWQgYW5vdGhlciByZWNvdmVyeSBh ZnRlciByZXN0YXJ0IGFuZCBzdXBwb3NlIG1iNCB3YXMgaW52YWxpZDogDQp8IG1iMSB8IG1i MiB8IG1iMyB8ICBlbWIgfCAgbWI0IHwgbWI1IHwgDQpsYXN0X2NoZWNrcG9pbnQgPSBlbWIn cG9zaXRpb24sICBsYXN0X2NwX3NlcSA9IG1iMSdzZXEgKyAxMQ0KU2luY2UgbWI0IHdhcyBp bnZhbGlkLCB3ZSB3b3VsZCBzdG9wIHJlY292ZXJpbmcgbWI1IHdoaWNoIHNob3VsZCBiZSBk aXNjYXJkZWQuDQpBZnRlciByZWNvdmVyeSwgbG9nX3N0YXJ0IHBvaW50cyB0byBtYjQgYW5k IHdlIHdvdWxkbid0IHdyaXRlIGEgZW1wdHkgbWV0YSBibG9jaw0KYmVjYXVzZSBjb25kaXRp b24gImN0eC5zZXEgPiBsb2ctPmxhc3RfY3Bfc2VxICsgMSIgZG9lc24ndCBzYXRpc2Z5LiBJ ZiB3ZSBhcmUgZ29pbmcgdG8NCndyaXRlIGEgdmFsaWQgbWV0YSBibG9jayBhbmQgY3Jhc2gg aGFwcGVucyBhZ2FpbiwgdGhlIG5ldyBtZXRhIGJsb2NrIHdpbGwgZmFsbCBpbnRvDQpwb3Np dGlvbiBvZiBtYjQgYW5kIHJlY292ZXJ5IHByb2Nlc3MgbWF5IGRvIGEgcmVjb3ZlcnkgdG8g bWI1IHNpbmNlIGl0J3Mgc2VxDQppcyBtYXRjaGVkLg0KDQpXaGF0IEkgdHJ5IHRvIHNheSBp cyB0aGF0IGlmIHRoZSBmaXJzdCBtZXRhIGJsb2NrICxub3Qgb25seSB0aGUgbWlkIG9uZSwg d2Ugd3JpdHRlbiB3YXMNCmludmFsaWQsIHRoZSBsb2cgcmVjb3ZlcnkgY291bGQgYnJpbmcg cHJvYmxlbSBoZXJlIHRvbyAuIEkgdGhpbmsgdGhlIGNvbmRpdGlvbiBmb3IgDQp3cml0ZSBh IGVtcHR5IG1ldGEgYmxvY2sgc2hvdWxkIGxpa2UgdGhpczoNCiAgICAtIGlmIChjdHguc2Vx ID4gbG9nLT5sYXN0X2NwX3NlcSArIDEpIHsNCiAgICArIGlmIChjdHguc2VxID4gbG9nLT5s YXN0X2NwX3Nlce+8iSB7DQoNCi0tLS0tLS0tLS0tLS0tLS0tLSBPcmlnaW5hbCAtLS0tLS0t LS0tLS0tLS0tLS0NCkZyb206ICAiU2hhb2h1YSBMaSI8c2hsaUBrZXJuZWwub3JnPjsNCkRh dGU6ICBUaHUsIE9jdCAyNywgMjAxNiAwMjozNSBBTQ0KVG86ICAiWmhlbmd5dWFuIExpdSI8 bGl1emhlbmd5dWFuQGt5bGlub3MuY24+Ow0KQ2M6ICAiU29uZyBMaXUiPHNvbmdsaXVicmF2 aW5nQGZiLmNvbT47ICJsaW51eC1yYWlkIjxsaW51eC1yYWlkQHZnZXIua2VybmVsLm9yZz47 ICJsaXV6aGVuZ3l1YW5nNTIxIjxsaXV6aGVuZ3l1YW5nNTIxQGdtYWlsLmNvbT47DQpTdWJq ZWN0OiAgUmU6IFtQQVRDSF0gbWQvcmFpZDU6IHdyaXRlIGFuIGVtcHR5IG1ldGEtYmxvY2sg d2hlbiBjcmVhdGluZ2xvZ3N1cGVyLWJsb2NrDQogDQpPbiBUdWUsIE9jdCAyNSwgMjAxNiBh dCAwODo0Mzo1MFBNICswODAwLCBaaGVuZ3l1YW4gTGl1IHdyb3RlOg0KPiBBZnRlciBkaXNj dXNzaW9uIHdpdGggbXkgY29sbGVhZ3VlLCBJIHRoaW5rIHRoZXJlIGlzIHN0aWxsIGEgcHJv YmxlbSB0aGF0DQo+IG1heSBoYXBwZW4gdmVyeSB1bmxpa2VseS5UaGUgc3VwZXJibG9jayBz aG91bGQgcG9pbnQgdG8gdGhlIGxhc3QgbWV0YQ0KPiBibG9jayB3ZSBoYXZlIHdyaXR0ZW4g YWZ0ZXIgbG9nIHJlY2xhaW0gb3IgcG9pbnQgdG8gdGhlIGVtdHB5IG1ldGEgYmxvY2sNCj4g YWZ0ZXIgbG9nIHJlY292ZXJ5LCBqdXN0IGNvbnNpZGVyIHdlIHdyaXRlIHNvbWUgbWV0YSBi bG9jayBiZWhpbmQgdGhlDQo+IHN1cGVyYmxvY2sgcG9zaXRpb24gYW5kIHN1cHBvc2UgY3Jh c2ggaGFwcGVucy4gSWYgdGhlIGZpcnN0IG1ldGEgYmxvY2sgd2UNCj4gaGF2ZSB3cml0dGVu IG5laWdoYm9yaW5nIHRoZSBzdXBlcmJsb2NrIHBvc2l0aW9uIGlzIGludmFsaWQsICBjdHgu c2VxIHdvdWxkIA0KPiBhbHNvIGVxdWFsIHRvIGxhc3RfY3Bfc2VxKzEgYWZ0ZXIgd2UgZGlk IGEgcmVjb3ZlcnkgLiBTbyB0aGUgc2FmZXN0IHdheSBpcyANCj4gd2UgYWx3YXlzIHdyaXRl IGFuIGVtcHR5IG1ldGEgYmxvY2sgYXQgY3R4LnBvcyBubyBtYXR0ZXIgaG93IG11Y2gNCj4g Y3R4LnJlcSBpcyBtb3JlIHRoYW4gbGFzdF9jcF9zZXEgYWZ0ZXIgd2UgZGlkIGEgcmVjb3Zl cnkuIA0KPiBIb3cgZG8geW91IHRoaW5rLCBTaGFvaHVhPyBJZiBpdCBpcyBuZWNlc3Nhcnks IEknZCByZXZlcnQgdGhpcyBwYXRjaCBhbmQNCj4gcmVzZW5kIG9uZS4NCg0KSSBkaWRuJ3Qg Z2V0IHRoZSBwb2ludC4gQ291bGQgeW91IHBsZWFzZSBlbGFib3JhdGUgaXQgYWdhaW4/DQoN ClRoYW5rcywNClNoYW9odWENCg0KPiANCj4gLS0tLS0tLS0tLS0tLS0tLS0tIE9yaWdpbmFs IC0tLS0tLS0tLS0tLS0tLS0tLQ0KPiBGcm9tOiAgIlNoYW9odWEgTGkiPHNobGlAa2VybmVs Lm9yZz47DQo+IERhdGU6ICBUdWUsIE9jdCAyNSwgMjAxNiAwNToyMyBBTQ0KPiBUbzogICJa aGVuZ3l1YW4gTGl1IjxsaXV6aGVuZ3l1YW5Aa3lsaW5vcy5jbj47DQo+IENjOiAgInNobGki PHNobGlAZmIuY29tPjsgIlNvbmcgTGl1Ijxzb25nbGl1YnJhdmluZ0BmYi5jb20+OyAibGlu dXgtcmFpZCI8bGludXgtcmFpZEB2Z2VyLmtlcm5lbC5vcmc+OyAibGl1emhlbmd5dWFuZzUy MSI8bGl1emhlbmd5dWFuZzUyMUBnbWFpbC5jb20+Ow0KPiBTdWJqZWN0OiAgUmU6IFtQQVRD SF0gbWQvcmFpZDU6IHdyaXRlIGFuIGVtcHR5IG1ldGEtYmxvY2sgd2hlbiBjcmVhdGluZyBs b2dzdXBlci1ibG9jaw0KPiAgDQo+IE9uIE1vbiwgT2N0IDI0LCAyMDE2IGF0IDA0OjE1OjU5 UE0gKzA4MDAsIFpoZW5neXVhbiBMaXUgd3JvdGU6DQo+ID4gSWYgc3VwZXJibG9jayBwb2lu dHMgdG8gYW4gaW52YWxpZCBtZXRhIGJsb2NrLCByNWxfbG9hZF9sb2cgd2lsbCBzZXQNCj4g PiBjcmVhdGVfc3VwZXIgd2l0aCB0cnVlIGFuZCBjcmVhdGUgYW4gbmV3IHN1cGVyYmxvY2ss IHRoaXMgcnVudGltZSBwYXRoDQo+ID4gd291bGQgYWx3YXlzIGhhcHBlbiBpZiB3ZSBkbyBu byB3cml0aW5nIEkvTyB0byB0aGlzIGFycmF5IHNpbmNlIGl0IHdhcw0KPiA+IGNyZWF0ZWQu IFdyaXRpbmcgYW4gZW1wdHkgbWV0YSBibG9jayBjb3VsZCBhdm9pZCB0aGlzIHVubmVjZXNz YXJ5DQo+ID4gYWN0aW9uIGF0IHRoZSBmaXJzdCB0aW1lIHdlIGNyZWF0ZWQgbG9nIHN1cGVy YmxvY2suDQo+ID4gDQo+ID4gQW5vdGhlciByZWFzb24gaXMgZm9yIHRoZSBjb3JyZXRuZXNz IG9mIGxvZyByZWNvdmVyeS4gQ3VycmVudGx5IHdlIGhhdmUNCj4gPiBiZWxsb3cgY29kZSB0 byBndWFyYW50ZWUgbG9nIHJldm9jZXJ5IHRvIGJlIGNvcnJlY3QuDQo+ID4gDQo+ID4gICAg ICAgICBpZiAoY3R4LnNlcSA+IGxvZy0+bGFzdF9jcF9zZXEgKyAxKSB7DQo+ID4gICAgICAg ICAgICAgICAgIGludCByZXQ7DQo+ID4gDQo+ID4gICAgICAgICAgICAgICAgIHJldCA9IHI1 bF9sb2dfd3JpdGVfZW1wdHlfbWV0YV9ibG9jayhsb2csIGN0eC5wb3MsIGN0eC5zZXEgKyAx MCk7DQo+ID4gICAgICAgICAgICAgICAgIGlmIChyZXQpDQo+ID4gICAgICAgICAgICAgICAg ICAgICAgICAgcmV0dXJuIHJldDsNCj4gPiAgICAgICAgICAgICAgICAgbG9nLT5zZXEgPSBj dHguc2VxICsgMTE7DQo+ID4gICAgICAgICAgICAgICAgIGxvZy0+bG9nX3N0YXJ0ID0gcjVs X3JpbmdfYWRkKGxvZywgY3R4LnBvcywgQkxPQ0tfU0VDVE9SUyk7DQo+ID4gICAgICAgICAg ICAgICAgIHI1bF93cml0ZV9zdXBlcihsb2csIGN0eC5wb3MpOw0KPiA+ICAgICAgICAgfSBl bHNlIHsNCj4gPiAgICAgICAgICAgICAgICAgbG9nLT5sb2dfc3RhcnQgPSBjdHgucG9zOw0K PiA+ICAgICAgICAgICAgICAgICBsb2ctPnNlcSA9IGN0eC5zZXE7DQo+ID4gICAgICAgICB9 DQo+ID4gDQo+ID4gSWYgd2UganVzdCBjcmVhdGVkIGEgYXJyYXkgd2l0aCBhIGpvdXJuYWwg ZGV2aWNlLCBsb2ctPmxvZ19zdGFydCBhbmQNCj4gPiBsb2ctPmxhc3RfY2hlY2twb2ludCBz aG91bGQgYWxsIGJlIDAsIHRoZW4gd2Ugd3JpdGUgdGhyZWUgbWV0YSBibG9jaw0KPiA+IHdo aWNoIGFyZSB2YWxpZCBleGNlcHQgbWlkIG9uZSBhbmQgc3VwcG9zZWQgY3Jhc2ggaGFwcGVu ZWQuIFRoZSBjdHguc2VxDQo+ID4gd291bGQgZXF1YWwgdG8gbG9nLT5sYXN0X2NwX3NlcSAr IDEgYW5kIGxvZy0+bG9nX3N0YXJ0IHdvdWxkIGJlIHNldCB0bw0KPiA+IHBvc2l0aW9uIG9m IG1pZCBpbnZhbGlkIG1ldGEgYmxvY2sgYWZ0ZXIgd2UgZGlkIGEgcmVjb3ZlcnksIHRoaXMg d2lsbA0KPiA+IGxlYWQgdG8gcHJvYmxlbXMgd2hpY2ggY291bGQgYmUgYXZvaWRlZCB3aXRo IHRoaXMgcGF0Y2guDQo+IA0KPiBUaGlzIHdvdWxkIGJlIHZlcnkgdW5saWtlbHksIGJ1dCBi ZXR0ZXIgdG8gZml4LiBBcHBsaWVkLCB0aGFua3Mh