From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jiang, Dave" Subject: Re: [RFC] raid5: add a log device to fix raid5/6 write hole issue Date: Wed, 1 Apr 2015 20:07:01 +0000 Message-ID: <1427918821.125860.139.camel@intel.com> References: <20150330222459.GA575371@devbig257.prn2.facebook.com> <20150401183630.GA3103@lazy.lzy> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: Content-Language: en-US Content-ID: <5A3FA96CCD9B3E4A8839A4364EF11F81@intel.com> Sender: linux-raid-owner@vger.kernel.org To: "Williams, Dan J" Cc: "linux-raid@vger.kernel.org" , "neilb@suse.de" , "Kernel-team@fb.com" , "piergiorgio.sartor@nexgo.de" , "shli@fb.com" , "songliubraving@fb.com" List-Id: linux-raid.ids DQpPbiBXZWQsIDIwMTUtMDQtMDEgYXQgMTg6NDYgKzAwMDAsIFdpbGxpYW1zLCBEYW4gSiB3cm90 ZToNCj4gT24gV2VkLCBBcHIgMSwgMjAxNSBhdCAxMTozNiBBTSwgUGllcmdpb3JnaW8gU2FydG9y DQo+IDxwaWVyZ2lvcmdpby5zYXJ0b3JAbmV4Z28uZGU+IHdyb3RlOg0KPiA+IE9uIFR1ZSwgTWFy IDMxLCAyMDE1IGF0IDA4OjQ3OjA0UE0gLTA3MDAsIERhbiBXaWxsaWFtcyB3cm90ZToNCj4gPj4g T24gTW9uLCBNYXIgMzAsIDIwMTUgYXQgMzoyNSBQTSwgU2hhb2h1YSBMaSA8c2hsaUBmYi5jb20+ IHdyb3RlOg0KPiA+PiA+IFRoaXMgaXMgbXkgYXR0ZW1wdCB0byBmaXggcmFpZDUvNiB3cml0ZSBo b2xlIGlzc3VlLCBpdCdzIG5vdCBmb3IgbWVyZ2UNCj4gPj4gPiB5ZXQsIEkgcG9zdCBpdCBvdXQg Zm9yIGNvbW1lbnRzLiBBbnkgY29tbWVudHMgYW5kIHN1Z2dlc3Rpb25zIGFyZQ0KPiA+PiA+IHdl bGNvbWUhDQo+ID4+ID4NCj4gPj4gPiBUaGFua3MsDQo+ID4+ID4gU2hhb2h1YQ0KPiA+PiA+DQo+ ID4+ID4gV2UgZXhwZWN0IGEgY29tcGxldGVkIHJhaWQ1LzYgc3RhY2sgd2l0aCByZWxpYWJpbGl0 eSBhbmQgaGlnaA0KPiA+PiA+IHBlcmZvcm1hbmNlLiBDdXJyZW50bHkgcmFpZDUvNiBoYXMgMiBp c3N1ZXM6DQo+ID4+ID4NCj4gPj4gPiAxLiByZWFkLW1vZGlmeS13cml0ZSBmb3Igc21hbGwgc2l6 ZSBJTy4gVG8gZml4IHRoaXMgaXNzdWUsIGEgY2FjaGUgbGF5ZXINCj4gPj4gPiBhYm92ZSByYWlk NS82IGNhbiBiZSB1c2VkIHRvIGFnZ3JlZ2F0ZSB3cml0ZSB0byBmdWxsIHN0cmlwZSB3cml0ZS4N Cj4gPj4gPiAyLiB3cml0ZSBob2xlIGlzc3VlLiBBIHdyaXRlIGxvZyBiZWxvdyByYWlkNS82IGNh biBmaXggdGhlIGlzc3VlLg0KPiA+PiA+DQo+ID4+ID4gV2UgcGxhbiB0byB1c2UgYSBTU0QgdG8g Zml4IHRoZSB0d28gaXNzdWVzLiBIZXJlIHdlIGp1c3QgZml4IHRoZSB3cml0ZQ0KPiA+PiA+IGhv bGUgaXNzdWUuDQo+ID4+ID4NCj4gPj4gPiAxLiBXZSBkb24ndCB0cnkgdG8gZml4IHRoZSBpc3N1 ZXMgdG9nZXRoZXIuIEEgY2FjaGUgbGF5ZXIgd2lsbCBkbyB3cml0ZQ0KPiA+PiA+IGFjY2VsZXJh dGlvbi4gQSBsb2cgbGF5ZXIgd2lsbCBmaXggd3JpdGUgaG9sZS4gVGhlIHNlcGVyYXRpb24gd2ls bA0KPiA+PiA+IHNpbXBsaWZ5IHRoaW5ncyBhIGxvdC4NCj4gPj4gPg0KPiA+PiA+IDIuIEN1cnJl bnQgYXNzdW1wdGlvbiBpcyBmbGFzaGNhY2hlL2JjYWNoZSB3aWxsIGJlIHVzZWQgYXMgdGhlIGNh Y2hlDQo+ID4+ID4gbGF5ZXIuIElmIHRoZXkgZG9uJ3Qgd29yayB3ZWxsLCB3ZSBjYW4gZml4IHRo ZW0gb3IgYWRkIGEgc2ltcGxlIGNhY2hlDQo+ID4+ID4gbGF5ZXIgZm9yIHJhaWQgd3JpdGUgYWdn cmVnYXRpb24gbGF0ZXIuIFdlIGFsc28gYXNzdW1lIGNhY2hlIGxheWVyIHdpbGwNCj4gPj4gPiBh YnNvcmIgd3JpdGUsIHNvIGxvZyBkb2Vzbid0IHdvcnJ5IGFib3V0IHdyaXRlIGxhdGVuY3kuDQo+ ID4+DQo+ID4+IEl0IHNlZW1zIG5laXRoZXIgYmNhY2hlIG5vciBkbS1jYWNoZSBhcmUgdGFja2xp bmcgdGhlIHdyaXRlLWJ1ZmZlcmluZw0KPiA+PiBwcm9ibGVtIGhlYWQgb24uLi4gdGhleSBzdGls bCBzZWVtIHRvIGJlIGNvbmNlcm5lZCB3aXRoIHNvbWUgYW1vdW50IG9mDQo+ID4+IHJlYWQgY2Fj aGluZyB3aGljaCBJIGNhbiBzZWUgYXMgdXNlZnVsIGZvciBmaWxlIHNlcnZlcnMgYW5kDQo+ID4+ IHdvcmtzdGF0aW9ucywgYnV0IG5vdCBuZWNlc3NhcmlseSBzY2FsZSBvdXQgc3RvcmFnZS4NCj4g Pj4NCj4gPj4gSSdsbCB0cnkgdG8gc2V0IGFzaWRlIHRpbWUgdG8gdGFrZSBhIGxvb2sgYXQgdGhl IHBhdGNoIHRoaXMgd2Vlay4NCj4gPg0KPiA+IFRoZXJlIGlzIG9uZSB0aGluZyBJIGRvIG5vdCBy ZWFsbHkgZ2V0Lg0KPiA+DQo+ID4gVGhlIHRhcmdldCBpcyB0byBhdm9pZCB0aGUgIndyaXRlIGhv bGUiLCB3aGljaCBoYXBwZW5zLA0KPiA+IGZvciBleGFtcGxlLCB3aGVuIHRoZXJlIGlzIGEgc3Vk ZGVuIHBvd2VyIGZhaWx1cmUuDQo+ID4NCj4gPiBOb3csIGhvdyBjYW4gYmUgYXNzdXJlZCwgaW4g dGhhdCBjYXNlLCB0aGF0IHRoZSAiY2FjaGUiDQo+ID4gZGV2aWNlIGlzIHNhZmUgYWZ0ZXIgdGhl IHBvd2VyIGlzIHJlc3RvcmVkPw0KPiANCj4gSWYgeW91IGxvc2UgdGhlIGNhY2hlIHRoZSBkYXRh LWxvc3MgZGFtYWdlIGlzIGdyZWF0ZXIsIGJ1dCB0aGlzIGhhcw0KPiBhbHdheXMgYmVlbiB0aGUg Y2FzZSB3aXRoIGhhcmR3YXJlLXJhaWQgYWRhcHRlcnMuDQo+IA0KPiA+IERvZXNuJ3QgdGhpcyBz b2x1dGlvbiBqdXN0IHNoaWZ0cyB0aGUgcHJvYmxlbSBmcm9tDQo+ID4gdGhlIGFycmF5IHRvIGEg ZGlmZmVyZW50IGRldmljZSAoU1NELCBmb3IgZXhhbXBsZSk/DQo+ID4NCj4gPiBTcGVha2luZyBv ZiBTU0QsIHRoZXNlIGFyZSBxdWl0ZSAicG93ZXIgZmFpbHVyZSINCj4gPiBzZW5zaXRpdmUsIGl0 IHNlZW1zLi4uDQo+IA0KPiBTaW1wbGUsIGlmIGEgY2FjaGUtZGV2aWNlIGlzIG5vdCBpdHNlbGYg cG93ZXItZmFpbHVyZSBzYWZlIHRoZW4gaXQNCj4gc2hvdWxkIG5vdCBiZSB1c2VkIGZvciBwb3dl ci1mYWlsdXJlIHByb3RlY3Rpb24uDQoNCkkgdGhpbmsgdGhpcyB3b3VsZCBiZSBhIGdvb2QgYXBw bGljYXRpb24gZm9yIHNvbWUgb2YgdGhlIG5ld2VyDQp0ZWNobm9sb2d5IGNvbWluZyBvdXQgc3Vj aCBhcyBOVkRJTU0gYW5kIHBlcnNpc3RlbnQgbWVtb3J5Lg0K