From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: mdadm seems not be doing rewrites on unreadable blocks Date: Tue, 30 Nov 2010 21:59:43 +1100 Message-ID: <20101130215943.395a7622@notabene.brown> References: <87oc98jgqb.fsf@poker.hands.com> <20101130115214.0b818e48@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: CoolCold Cc: Philip Hands , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, 30 Nov 2010 13:40:25 +0300 CoolCold wro= te: > On Tue, Nov 30, 2010 at 3:52 AM, Neil Brown wrote: > > When you write 512 byte blocks to a block device, it will read a 40= 96 byte > > block, update the 512 bytes, and write the 4096 bytes back. > > > > > >> > >> Which gives rise to this: > >> > >> [325487.740650] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 act= ion 0x0 > >> [325487.740746] ata2.00: irq_stat 0x00060002, device error via D2H= FIS > >> [325487.740841] ata2.00: failed command: READ DMA > > > > Yep. =A0read error while trying to pre-read the 4K block. > Hmm, is true for any block device? i.e. if blockdev --getss reports > sector size is 512 byte. Or this is related to page size? >=20 PAGE_SIZE. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html