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From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: The bug of iput() removal from flusher thread?
Date: Wed, 21 Nov 2012 00:05:33 -0800	[thread overview]
Message-ID: <20121121000533.a0ab9eea.akpm@linux-foundation.org> (raw)
In-Reply-To: <20121121014851.GH10507@quack.suse.cz>

On Wed, 21 Nov 2012 02:48:51 +0100 Jan Kara <jack@suse.cz> wrote:

> +/*
> + * Add inode to LRU if needed (inode is unused and clean).
> + *
> + * Needs inode->i_lock held.
> + */
> +void inode_add_lru(struct inode *inode)
> +{
> +	if (!(inode->i_state & (I_DIRTY | I_FREEING | I_SYNC)) &&
> +	    !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE)
> +		inode_lru_list_add(inode);
> +}

Is i_lock sufficient to stabilise i_count?

<looks at the code a bit>

Is evict_inodes() wrong to test i_count outside i_lock?

invalidate_inodes() looks better.

can_unuse() must be called under i_lock, and is.  Apparently this
requirement was sufficiently obvious to not meed documenting.

prune_icache_sb() gets it right.

iput() gets it right.

So to answer my own question: yes, it is sufficient.  But a) the
comment for inode.i_lock is out of date and b) evict_inodes() looks
fishy.

  parent reply	other threads:[~2012-11-21  8:05 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-17  8:42 The bug of iput() removal from flusher thread? OGAWA Hirofumi
2012-11-19  8:56 ` OGAWA Hirofumi
2012-11-19 14:51   ` Jan Kara
2012-11-19 19:41     ` Jan Kara
2012-11-19 20:51       ` OGAWA Hirofumi
2012-11-19 21:24         ` Jan Kara
2012-11-19 21:53           ` OGAWA Hirofumi
2012-11-21  1:11             ` Jan Kara
2012-11-21  1:48               ` Jan Kara
2012-11-21  2:44                 ` Dave Chinner
2012-11-21 17:08                   ` Jan Kara
2012-11-21  8:05                 ` Andrew Morton [this message]
2012-11-21  8:22                   ` Dave Chinner
2012-11-20 22:37       ` Dave Chinner
2012-11-21  1:30         ` Jan Kara

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