From: Theodore Tso <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: "홍신 shin hong" <hongshin@gmail.com>, linux-ext4@vger.kernel.org
Subject: Re: a question for i_inode's i_size in ext2
Date: Sat, 20 Sep 2008 02:35:02 -0400 [thread overview]
Message-ID: <20080920063502.GB12762@mit.edu> (raw)
In-Reply-To: <20080920032522.GB9633@atrey.karlin.mff.cuni.cz>
On Sat, Sep 20, 2008 at 05:25:22AM +0200, Jan Kara wrote:
> Reading i_size is a different matter - see
> i_size_read function. We use seqlock for that - essentially we use an
> atomic counter which is incremented on every change of i_size and check
> that it's value before we started reading i_size and after we have
> finished reading it has not changed. I hope this helps.
Just to clarify for Shin Hong's benefit: this is necessary only on SMP
(or CONFIG_PREEMPT) 32-bit platforms in order to make sure we read a
coherent 64-bit i_size value.
- Ted
next prev parent reply other threads:[~2008-09-20 6:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 7:21 a question for i_inode's i_size in ext2 홍신 shin hong
2008-09-19 23:32 ` Theodore Tso
2008-09-20 3:25 ` Jan Kara
2008-09-20 6:35 ` Theodore Tso [this message]
[not found] ` <2014bcab0809252152i6fef9babx242e821c4f0d5a7b@mail.gmail.com>
2008-09-26 4:53 ` 홍신 shin hong
2008-09-26 14:41 ` Theodore Tso
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