linux-kernel - Re: [PATCH v6 0/3] fallocate for block devices to provide zero-out

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: <CA+55aFxcXOL+sqWN1yze7d5fQZmTa_6Tg6D6hJ+ReYyKMFxzSg@mail.gmail.com>
Date:	Fri, 4 Mar 2016 19:17:24 -0800
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	Jens Axboe <axboe@...nel.dk>,
	Christoph Hellwig <hch@...radead.org>,
	"Theodore Ts'o" <tytso@....edu>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Linux API <linux-api@...r.kernel.org>,
	Dave Chinner <david@...morbit.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	shane.seymour@....com, Bruce Fields <bfields@...ldses.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	Jeff Layton <jlayton@...chiereds.net>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v6 0/3] fallocate for block devices to provide zero-out

On Fri, Mar 4, 2016 at 4:55 PM, Darrick J. Wong <darrick.wong@...cle.com> wrote:
>
> This is a redesign of the patch series that fixes various interface
> problems with the existing "zero out this part of a block device"
> code.  BLKZEROOUT2 is gone.

I replied to two of the patches with small nits, but on the whole I
like it. The only nit that I think is serious is that you shouldn't be
requiring people to have to use FALLOC_FL_KEEP_SIZE.

If anything, you might just change that logic to say: If
FALLOC_FL_KEEP_SIZE is set, then we truncate the hole punching/zeroing
to the size of the device. So people could do something like

  fallocate(fd,
        FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
        0, ~0);

to trim the whole device (and if FALLOC_FL_KEEP_SIZE isn't set, then
the above would be an error simply because the requested hole was
bigger than the device)

            Linus