linux-kernel - Should a block device enforce block atomicity?

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 for Android: free password hash cracker in your pocket

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

Date:	Mon, 30 Jun 2008 09:51:16 +0300
From:	"Erez Zilber" <erezzi.list@...il.com>
To:	linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Should a block device enforce block atomicity?

Hi,

I have a question about block devices and whether they are required to
enforce block atomicity:

I read the code of drivers/block/brd.c, and I didn't see any locking
when blocks are read/written. I also looked at the block layer code
that calls brd and didn't find any locking there. Does it mean that
there's no block atomicity (i.e. multiple threads can write a single
block at the same time)? Is there any hidden assumption here? Is this
the responsibility of the application to do that (e.g. not start a
WRITE request before other READ/WRITE requests to the same block were
completed)?

Thanks,
Erez
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/