linux-kernel - Re: [PATCH v2] fat: editions to support fat

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]

Date:	Mon, 15 Oct 2012 01:20:16 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Namjae Jeon <linkinjeon@...il.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Ravishankar N <cyberax82@...il.com>,
	Amit Sahrawat <amit.sahrawat83@...il.com>
Subject: Re: [PATCH v2] fat: editions to support fat_fallocate()

Namjae Jeon <linkinjeon@...il.com> writes:

> Implement preallocation via the fallocate syscall on VFAT partitions.
> This patch is based on an earlier patch of the same name which had some
> issues detailed below and did not get accepted. Refer
> https://lkml.org/lkml/2007/12/22/130.
>
> a)The preallocated space was not persistent across remounts when the
> FALLOC_FL_KEEP_SIZE flag was set. Also, writes to the file allocated new
> clusters instead of using the preallocated area.
>
> Consider the scenario:
> mount-->preallocate space for a file --> unmount.
> In the old patch,the preallocated space was not reflected for that
> file (verified using the 'du' command).
>
> This is now fixed with modifications to fat_fill_inode().

What is real usage pattern of persistent across remounts on FAT? If once
device was unmounted, we can't know the state of FS anymore, there are
many implementations of FAT. And preallocation is not in the spec.

I worry to break something. And I guess the freeing preallocation on
last close may fix the issue for usage.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
--
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/