From: "Theodore Ts'o" <tytso@mit.edu>
To: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] ext4: fix suboptimal seek_{data,hole} extents traversial
Date: Tue, 25 Nov 2014 16:14:33 -0500 [thread overview]
Message-ID: <20141125211433.GB28449@thunk.org> (raw)
In-Reply-To: <1413552334-32240-1-git-send-email-dmonakhov@openvz.org>
On Fri, Oct 17, 2014 at 05:25:34PM +0400, Dmitry Monakhov wrote:
> It is rediculus practice to scan inode block by block, this technique
> applicable only for old indirect files. This takes signifficant amount
> of time for really large files. Let's reuse ext4_fiemap which already
> traverse inode-tree in most optimal meaner.
>
> TESTCASE:
> ftruncate64(fd, 0);
> ftruncate64(fd, 1ULL << 40);
> /* lseek will spin very long time */
> lseek64(fd, 0, SEEK_DATA);
> lseek64(fd, 0, SEEK_HOLE);
>
>
> Original report: https://lkml.org/lkml/2014/10/16/620
>
> ##################################
> BTW: Why do we need i_mutex here?
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Note: this patch causes generic/285 to loop forever in inline-data
mode. My guess is in the special case handling of inline data in
ext4_fiemap not playing well with this change, but I haven't had a
chance to look deeply into this yet.
- Ted
next prev parent reply other threads:[~2014-11-25 21:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-16 5:57 kernel BUG at fs/ext4/inode.c:2982! Dave Jones
2014-10-16 9:31 ` Dmitry Monakhov
2014-10-16 14:33 ` Dave Jones
2014-10-16 20:15 ` Dave Jones
2014-10-16 22:03 ` Dmitry Monakhov
2014-10-17 13:25 ` [PATCH] ext4: fix suboptimal seek_{data,hole} extents traversial Dmitry Monakhov
2014-11-25 21:14 ` Theodore Ts'o [this message]
2014-11-27 14:48 ` Dmitry Monakhov
2014-11-28 15:02 ` Dmitry Monakhov
2014-11-29 17:52 ` Theodore Ts'o
2014-12-01 11:25 ` Dmitry Monakhov
2014-10-17 17:27 ` kernel BUG at fs/ext4/inode.c:2982! Dave Jones
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