From: Theodore Ts'o <tytso@mit.edu>
To: Zheng Liu <gnehzuil.liu@gmail.com>
Cc: linux-ext4@vger.kernel.org, George Spelvin <linux@horizon.com>,
Zheng Liu <wenqing.lz@taobao.com>
Subject: Re: [PATCH 2/2 v2] debugfs: dump a sparse file as a new sparse file
Date: Tue, 1 Jan 2013 15:38:58 -0500 [thread overview]
Message-ID: <20130101203858.GB12554@thunk.org> (raw)
In-Reply-To: <1357043415-24668-3-git-send-email-wenqing.lz@taobao.com>
On Tue, Jan 01, 2013 at 08:30:15PM +0800, Zheng Liu wrote:
> +errcode_t ext2fs_file_read2(ext2_file_t file, void *buf,
> + unsigned int wanted, unsigned int *got,
> + ext2_off64_t *seek)
I'm a bit concenred about this abstraction. Consider what happens if
wanted is greater than a block size --- for example, consider if
wanted is 16k, and every other 1k block is uninitialized.
Then ext2fs_file_read2() will return *got set to 8k, and *seek set to
8k, and the buffer will contain the blocks that are initialized packed
up right against each other.
Worse, ext2fs_file_read() will do the same thing, so this commit
changes how ext2fs_file_read() functions, and a program which expects
to get the correct contents from the file will malfunction.
- Ted
next prev parent reply other threads:[~2013-01-01 20:39 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-01 12:30 [PATCH 0/2 v2] debugfs: dump a sparse file as a new sparse file Zheng Liu
2013-01-01 12:30 ` [PATCH 1/2 v2] debugfs: fixup the hard-coded buffer length in dump_file Zheng Liu
2013-01-01 20:14 ` Theodore Ts'o
2013-01-01 12:30 ` [PATCH 2/2 v2] debugfs: dump a sparse file as a new sparse file Zheng Liu
2013-01-01 20:38 ` Theodore Ts'o [this message]
2013-01-04 4:05 ` Zheng Liu
2013-01-04 19:37 ` Theodore Ts'o
2013-01-05 4:45 ` Zheng Liu
2013-01-09 14:58 ` Theodore Ts'o
2013-01-09 15:34 ` Zheng Liu
2013-01-10 0:42 ` George Spelvin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130101203858.GB12554@thunk.org \
--to=tytso@mit.edu \
--cc=gnehzuil.liu@gmail.com \
--cc=linux-ext4@vger.kernel.org \
--cc=linux@horizon.com \
--cc=wenqing.lz@taobao.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.