Re: Copying Data Blocks

["Manish Katiyar" <mkatiyar@gmail.com>]

On Tue, Jan 6, 2009 at 10:15 PM, Rohit Sharma <imreckless@gmail.com> wrote:
> On Tue, Jan 6, 2009 at 7:42 PM, rishi agrawal <postrishi@gmail.com> wrote:
>> yes i suppose the donor inode is known
>> moreover the receiver inode's number is also known
>>
>> On Tue, Jan 6, 2009 at 6:54 PM, Manish Katiyar <mkatiyar@gmail.com> wrote:
>>>
>>> On Tue, Jan 6, 2009 at 4:06 PM, Rohit Sharma <imreckless@gmail.com> wrote:
>>> > I want to read data blocks from one inode
>>> > and copy it to other inode.
>>> >
>>> > I mean to copy data from data blocks associated with one inode
>>> > to the data blocks associated with other inode.
>>>
>>> Copying 4K chunk of data itself is a costly operation. and depending
>
> Yes its a costly operation, but if this can be done then
> we can definitely copy n blocks at a time.
>
>>> on the size of your donor inode this can be huge . Why do you want to
>>> do that ? Do you know the inode of the donor inode ?
>
> For physically relocating a file from one disk to other.
>
> Yes Manish, i know the donor inode and i will create the reciever inode.

I am guessing .......will something like this work ?

ino_t donor_inode_num;
struct inode *donor_inode = FS_iget(sb , donor_inode_num);
struct FS_inode_info * fsi = FSI(donor_inode) ;   // Do the regular
container_of stuff here

for ( i = 0; i < (donor_inode->i_size + sb->s_blocksize -
1)/sb->s_blocksize ; i ++ ) {
    // Do a memmove or memcpy here from fsi->i_data[i]
}

I am not sure though how will you prevent the donor inode from being
changed/resized during this period.

Thanks -
Manish


>
> Can we do that in kernel space.?
>>>
>>> thanks -
>>> Manish
>>> >
>>> > Is that possible in kernel space.?
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>>
>>
>>
>> --
>> Regards,
>> Rishi B. Agrawal
>>
>>
>