From: Robert Yang <liezhi.yang@windriver.com>
To: <linux-ext4@vger.kernel.org>, <tytso@mit.edu>, <dvhart@linux.intel.com>
Subject: Re: [RFC 00/10] e2fsprogs/mke2fs: add an option: -d root-directory
Date: Mon, 2 Sep 2013 20:20:02 +0800 [thread overview]
Message-ID: <52248272.2000907@windriver.com> (raw)
In-Reply-To: <20130902115510.GA1106@gmail.com>
On 09/02/2013 07:55 PM, Zheng Liu wrote:
> On Mon, Sep 02, 2013 at 02:46:33PM +0800, Robert Yang wrote:
>>
>>
>> On 09/01/2013 11:26 AM, Zheng Liu wrote:
>>> Hi Robert,
>>>
>>> On Wed, Aug 28, 2013 at 01:25:50PM +0800, Robert Yang wrote:
>>>> This option is used for adding the files from the root-directory to the
>>>> filesystem, it is similiar to genext2fs, but genext2fs doesn't fully
>>>> support ext4.
>>>>
>>>> * Questions
>>>> - Is such an option acceptable ?
>>>>
>>>> - Most of the code have been in debugfs/debugfs.c already, I moved them to
>>>> misc/util.c and modified them to let both mke2fs and debugfs can use them,
>>>> maybe we should put these code in another separate file ?
>>>>
>>>> - Where can I get the up-to-date development git repo, please? I think that
>>>> there would be conflicts with the dev git repo, I'd like to rebase it if I
>>>> can get the repo, currently, I'm using this one:
>>>>
>>>> http://git.kernel.org/cgit/fs/ext2/e2fsprogs.git
>>>>
>>>> * The size impact on misc/mke2fs:
>>>> 1,677,297 -> 1,728,110 (non stripped, about 50K increases)
>>>> 316,968 -> 325,160 (stripped, 8K increases)
>>>>
>>>> Please feel free to give your comments.
>>>
>>> If I understand correctly, after applied this patch set, we can copy
>>> some files from a directory that is indicated by '-d' option when we
>>> create a new ext4 file system. My concern is why we need to add this
>>> option? Without this option I can use 'mkfs.ext4 ${DEV}', 'mount ${DEV}
>>> ${MNT}' and 'cp ${SRC} ${MNT}' to do the same thing. I am not
>>> convinced. Could you please describe more details for this patch set?
>>>
>>
>> Hi Zheng,
>>
>> Yes, you are right, we can run mkfs/mount/cp to do the same thing,
>> but the problem is that the "mount" command requires the root privilege,
>> but we may not have it when we are working on a sever (the mkfs doesn't
>> need the root privilege), for example
>>
>> $ dd if=/dev/zero of=test.img count=0 bs=1k seek=2M
>> $ mke2fs -t ext4 -F test.img -d <root-dir>
>>
>> Will create an ext4 image with the files copied without the root privilege.
>
> Interesting. As you said above, if you haven't the root privilege, you
> won't use this file system. But at least this file system will be used
> by some one who have the root privilege. He/she can do the rest of
> works. That means that you do 'dd/mke2fs' and he or she does
> 'mount/cp'. I don't see any reason that all dirs and files must be
> created by mke2fs. Any real case that needs to do this?
>
Hi Zheng,
For example, in Linux embedded development, we usually create a filesystem
image which contains the linux embedded OS, this image can be used by qemu,
Live CD and so on.
// Robert
> - Zheng
>
>
next prev parent reply other threads:[~2013-09-02 12:20 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-28 5:25 [RFC 00/10] e2fsprogs/mke2fs: add an option: -d root-directory Robert Yang
2013-08-28 5:25 ` [RFC 01/10] mke2fs.c: " Robert Yang
2013-10-14 2:41 ` Theodore Ts'o
2013-10-14 12:22 ` [PATCH] mke2fs: fix up the commit "mke2fs.c: add an option: -d root-directory" Theodore Ts'o
2013-10-14 16:26 ` [RFC 01/10] mke2fs.c: add an option: -d root-directory Darren Hart
2013-10-15 1:38 ` Robert Yang
2013-08-28 5:25 ` [RFC 02/10] misc/util.c: implement populate_fs() Robert Yang
2013-08-28 5:25 ` [RFC 03/10] misc/util.c: create special file Robert Yang
2013-08-28 5:25 ` [RFC 04/10] misc/util.c: create symlink Robert Yang
2013-08-28 5:25 ` [RFC 05/10] misc/util.c: copy regular file Robert Yang
2013-08-28 5:25 ` [RFC 06/10] misc/util.c: create directory Robert Yang
2013-08-28 5:25 ` [RFC 07/10] misc/util.c: set more information for inode Robert Yang
2013-08-28 5:25 ` [RFC 08/10] misc/util.c: handle hardlinks Robert Yang
2013-08-28 5:25 ` [RFC 09/10] mke2fs.8.in: update the manual for the -d option Robert Yang
2013-08-28 5:26 ` [RFC 10/10] debugfs: use the functions in misc/util.c Robert Yang
2013-10-14 14:40 ` Theodore Ts'o
2013-09-01 3:26 ` [RFC 00/10] e2fsprogs/mke2fs: add an option: -d root-directory Zheng Liu
2013-09-02 6:46 ` Robert Yang
2013-09-02 11:55 ` Zheng Liu
2013-09-02 12:20 ` Robert Yang [this message]
2013-09-02 12:27 ` Zheng Liu
2013-09-16 21:04 ` Darren Hart
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