linux-kernel - Re: [RFC] blk: increase logical_block

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <978119764.6177321.1483974560473.JavaMail.zimbra@redhat.com>
Date:   Mon, 9 Jan 2017 10:09:20 -0500 (EST)
From:   Jerome Marchand <jmarchan@...hat.com>
To:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc:     Minchan Kim <minchan@...nel.org>, Jens Axboe <axboe@...nel.dk>,
        Hyeoncheol Lee <cheol.lee@....com>,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Robert Jennings <rcj@...ux.vnet.ibm.com>
Subject: Re: [RFC] blk: increase logical_block_size to unsigned int



----- Original Message -----
> From: "Sergey Senozhatsky" <sergey.senozhatsky@...il.com>
> To: "Minchan Kim" <minchan@...nel.org>
> Cc: "Jens Axboe" <axboe@...nel.dk>, "Hyeoncheol Lee" <cheol.lee@....com>, linux-block@...r.kernel.org,
> linux-kernel@...r.kernel.org, "Andrew Morton" <akpm@...ux-foundation.org>, "Sergey Senozhatsky"
> <sergey.senozhatsky@...il.com>, "Robert Jennings" <rcj@...ux.vnet.ibm.com>, "Jerome Marchand" <jmarchan@...hat.com>
> Sent: Monday, January 9, 2017 3:33:44 PM
> Subject: Re: [RFC] blk: increase logical_block_size to unsigned int
> 
> On (01/09/17 14:04), Minchan Kim wrote:
> > Mostly, zram is used as swap system on embedded world so it want to do IO
> > as PAGE_SIZE aligned/size IO unit. For that, one of the problem was
> > blk_queue_logical_block_size(zram->disk->queue, PAGE_SIZE) made overflow
> > in *64K page system* so [1] changed it to constant 4096.
> > Since that, partial IO can happen so zram should handle it which makes zram
> > complicated[2].
> > 
> 
> I thought that zram partial IO support is there because some file
> systems cannot cope with large logical_block_size. like FAT, for
> example. am I wrong?

Yes indeed. When we discussed the patch adding the partial I/O, increasing the
size of logical_block was considered. The reason we didn't go the easy path was
that not all block users could handle 64k blocks. FAT is one of them.

Jerome

> 
> 	-ss
>