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From: Theodore Ts'o <tytso@mit.edu>
To: Zheng Liu <gnehzuil.liu@gmail.com>
Cc: linux-ext4@vger.kernel.org, Zheng Liu <wenqing.lz@taobao.com>
Subject: Re: [PATCH] ext4: take i_mutex in ext4_symlink to eliminate a warning from ext4_truncate
Date: Wed, 27 Mar 2013 09:41:10 -0400	[thread overview]
Message-ID: <20130327134110.GI5861@thunk.org> (raw)
In-Reply-To: <1364390347-4360-1-git-send-email-wenqing.lz@taobao.com>

On Wed, Mar 27, 2013 at 09:19:07PM +0800, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@taobao.com>
> 
> After applied this commit (8e4061cb), we will get a warning from
> ext4_truncate when i_mutex isn't taken.  Here the assumption is that
> i_mutex should be taken when we do a truncation.  In ext4_symlink we
> could need to call ext4_truncate to trim some blocks beyond i_size, but
> the i_mutex isn't taken.

Hmm, and this is why I added the warning.  Even after looking your
patch, I'm having trouble finding the codepath that results in
ext4_truncate() getting called from __page_symlink().  Can you send
the stack trace from the WARN_ON, just so I can see what I missed?

Thanks,

						- Ted

  reply	other threads:[~2013-03-27 13:41 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-27 13:19 [PATCH] ext4: take i_mutex in ext4_symlink to eliminate a warning from ext4_truncate Zheng Liu
2013-03-27 13:41 ` Theodore Ts'o [this message]
2013-03-27 14:02   ` Zheng Liu
2013-03-27 13:51     ` Theodore Ts'o
2013-03-27 15:07       ` Zheng Liu
2013-03-27 15:19         ` Zheng Liu
2013-03-27 15:12           ` Theodore Ts'o
2013-03-27 15:35             ` Zheng Liu
2013-03-28 14:06               ` Theodore Ts'o
2013-04-01 15:23                 ` [PATCH] fs: take i_mutex in __page_symlink() Theodore Ts'o
2013-04-01 16:35                   ` Al Viro
2013-04-01 17:38                     ` Theodore Ts'o
2013-04-02  8:19                   ` Dmitry Monakhov
2013-03-27 14:04     ` [PATCH] ext4: take i_mutex in ext4_symlink to eliminate a warning from ext4_truncate Zheng Liu

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