From: Namjae Jeon <linkinjeon@gmail.com>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Andrew Bartlett <abartlet@samba.org>,
linux-kernel@vger.kernel.org, Ravishankar N <cyberax82@gmail.com>,
Amit Sahrawat <amit.sahrawat83@gmail.com>,
Nam-Jae Jeon <namjae.jeon@samsung.com>,
Ravishankar N <ravi.n1@samsung.com>,
Amit Sahrawat <a.sahrawat@samsung.com>
Subject: Re: Read support for fat_fallocate()? (was [v2] fat: editions to support fat_fallocate())
Date: Tue, 19 Feb 2013 00:15:54 +0900 [thread overview]
Message-ID: <CAKYAXd94jVs4SMdVUEsnsYjApru=+8cWFmXO3L_NAvwM1ge6cw@mail.gmail.com> (raw)
In-Reply-To: <878v6lzmzk.fsf@devron.myhome.or.jp>
2013/2/18 OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
> Namjae Jeon <linkinjeon@gmail.com> writes:
>
>>> Hm. My concerns are compatibility and reliability. Although We can
>>> change on-disk format if need, but I don't think it can be compatible
>>> and reliable. If so, who wants to use it? I feel there is no reason to
>>> use FAT if there is no compatible.
>>>
>>> Well, anyway, possible solution would be, we can pre-allocate physical
>>> blocks via fallocate(2) or something, but discard pre-allocated blocks
>>> at ->release() (or before unmount at least). This way would have
>>> compatibility (no on-disk change over unmount) and possible breakage
>>> would be same with normal extend write patterns on kernel crash
>>> (i.e. Windows or fsck will truncate after i_size).
>> Hi OGAWA.
>> We don't need to consider device unplugging case ?
>> If yes, I can rework fat fallocate patch as your suggestion.
>
> In my suggestion, I think, kernel crash or something like unplugging
> cases handles has no change from current way.
>
> Any pre-allocated blocks are truncated by fsck as inconsistency state,
> like crash before updating i_size for normal extend write. I.e. across
> unmount, nobody care whether pre-allocated or not. IOW, if there is
> inconsistent between i_size and cluster chain (includes via
> fallocate(2)) across unmount, it should be handled as broken state.
>
> In short, the lifetime of pre-allocated blocks are from fallocate(2) to
> ->release() only.
Okay, I will post updated fat fallocate patch after looking into more.
Thanks.
>
> Thanks.
> --
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
prev parent reply other threads:[~2013-02-18 15:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-13 14:31 [PATCH v2] fat: editions to support fat_fallocate() Namjae Jeon
2012-10-14 16:20 ` OGAWA Hirofumi
2012-10-16 4:12 ` Namjae Jeon
2012-10-16 10:14 ` OGAWA Hirofumi
2012-10-17 10:57 ` Namjae Jeon
2012-10-21 23:54 ` OGAWA Hirofumi
2012-10-22 15:10 ` Namjae Jeon
2012-10-23 7:19 ` OGAWA Hirofumi
2012-10-23 7:24 ` Namjae Jeon
2013-02-14 2:40 ` Read support for fat_fallocate()? (was [v2] fat: editions to support fat_fallocate()) Andrew Bartlett
2013-02-14 2:48 ` Andrew Bartlett
2013-02-14 6:44 ` Namjae Jeon
2013-02-14 7:07 ` Andrew Bartlett
2013-02-14 9:52 ` Namjae Jeon
2013-02-15 3:49 ` Andrew Bartlett
2013-02-18 11:36 ` OGAWA Hirofumi
2013-02-18 13:11 ` Andrew Bartlett
2013-02-18 14:25 ` Namjae Jeon
2013-02-18 14:59 ` OGAWA Hirofumi
2013-02-18 15:15 ` Namjae Jeon [this message]
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