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From: Jamie Lokier <jamie@shareable.org>
To: Shaya Potter <spotter@cs.columbia.edu>
Cc: Christoph Hellwig <hch@infradead.org>, linux-fsdevel@vger.kernel.org
Subject: Re: which dentry a page belongs to
Date: Fri, 23 Apr 2004 22:37:47 +0100	[thread overview]
Message-ID: <20040423213747.GA8915@mail.shareable.org> (raw)
In-Reply-To: <1082743539.1943.84.camel@zaphod>

Shaya Potter wrote:
> right, I know i can do that (or on lookup(), or on open() ) but that
> basically limits me to a open/close transaction for versioning.  Can't
> ioctl the fs, and cause all future writes to be in a new version.

"all future writes" is not very well defined with shared writable mappings.

Imagine this:

    1. program write to a page, dirty bit is set in pte

[6 weeks later...]

    2. you do the ioctl
    3. your writepage gets called

Now you will store an update for a change which happened 6 weeks
before you called the ioctl().  Is that what you really wanted?
Perhaps it is.

-- Jamie

  reply	other threads:[~2004-04-23 21:37 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-23 14:57 which dentry a page belongs to Shaya Potter
2004-04-23 15:14 ` Jamie Lokier
2004-04-23 15:42   ` Shaya Potter
2004-04-23 16:37     ` Christoph Hellwig
2004-04-23 16:52       ` Shaya Potter
2004-04-23 17:01         ` Christoph Hellwig
2004-04-23 17:18           ` Shaya Potter
2004-04-23 17:22             ` Christoph Hellwig
2004-04-23 17:32               ` Shaya Potter
2004-04-23 17:37             ` Jamie Lokier
2004-04-23 17:59               ` Shaya Potter
2004-04-23 22:13                 ` Jamie Lokier
2004-04-23 18:05               ` Shaya Potter
2004-04-23 21:37                 ` Jamie Lokier [this message]
2004-04-23 22:26                   ` Shaya Potter
2004-04-23 22:49                     ` Jamie Lokier
2004-04-25  5:23                       ` Shaya Potter
2004-04-25 23:22                         ` Erez Zadok
2004-04-24  8:53           ` Jan Hudec
2004-04-24  8:44       ` Jan Hudec
2004-04-24  9:20         ` Christoph Hellwig
2004-04-24  9:32           ` Jan Hudec

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