From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 03/22] ext4: Do not iput inode under running transaction in ext4_mkdir()
Date: Sun, 20 Oct 2019 21:21:05 -0400 [thread overview]
Message-ID: <20191021012105.GE6799@mit.edu> (raw)
In-Reply-To: <20191003220613.10791-3-jack@suse.cz>
On Fri, Oct 04, 2019 at 12:05:49AM +0200, Jan Kara wrote:
> When ext4_mkdir() fails to add entry into directory, it ends up dropping
> freshly created inode under the running transaction and thus inode
> truncation happens under that transaction. That breaks assumptions that
> ext4_evict_inode() does not get called from a transaction context
> (although I'm not aware of any real issue) and is completely
> unnecessary. Just stop the transaction before dropping inode reference.
>
> CC: stable@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
If we call ext4_journal_stop(handle) before calling iput(inode),
there's a chance that we could crash with the inode with i_link_counts
== 0, but we won't have yet call ext4_evict_inode() to mark the inode
as free in the inode bitmap. This would result in a inode leak.
Also, this isn't the only place where we can enter ext4_evict_inode()
with an active handle; the same situation arise in ext4_add_nondir(),
and for the same reason.
So I think the code is right as is. Do you agree?
- Ted
next prev parent reply other threads:[~2019-10-21 1:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191003215523.7313-1-jack@suse.cz>
2019-10-03 22:05 ` [PATCH 01/22] jbd2: Fix possible overflow in jbd2_log_space_left() Jan Kara
2019-10-21 1:08 ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 03/22] ext4: Do not iput inode under running transaction in ext4_mkdir() Jan Kara
2019-10-21 1:21 ` Theodore Y. Ts'o [this message]
2019-10-24 10:19 ` Jan Kara
2019-10-24 12:09 ` Theodore Y. Ts'o
2019-10-24 13:37 ` Jan Kara
2019-11-04 12:35 ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 04/22] ext4: Fix credit estimate for final inode freeing Jan Kara
2019-10-21 1:07 ` Theodore Y. Ts'o
2019-10-24 10:30 ` Jan Kara
2019-11-05 16:44 ` [PATCH 01/25] jbd2: Fix possible overflow in jbd2_log_space_left() Jan Kara
2019-11-05 16:44 ` [PATCH 05/25] ext4: Do not iput inode under running transaction Jan Kara
2019-11-05 16:44 ` [PATCH 06/25] ext4: Fix credit estimate for final inode freeing Jan Kara
2019-11-05 21:00 ` Theodore Y. Ts'o
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