On Tue, Jan 6, 2009 at 11:09 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote:
> On Tue, Jan 6, 2009 at 11:06 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote:
>> On Tue, Jan 6, 2009 at 10:58 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote:
>>> On Tue, Jan 6, 2009 at 10:55 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote:
>>>> We can find out no. of block currently being used by the donor inode,
>>>> The data we read from donor inode has to be in some buffer or page,
>>>
>>> Since we know the blocknumber of donor inode, it should be possible to
>>> do a raw read and get the memory address of the data page using
>>> sb_bread() and then accessing bh->b_data . Isn't it ?
>>
>> Yes that's the way we can read blocks but the major issue here
>> is copying this content to newly allocated block.
>
> Apart from performance, is there anything else you are worried about ?
Performance is only a bottleneck,
this can be done in user land
but kernel space solution will be more efficient.
>
> Thanks -
> Manish
>
>
>
>>>
>>> Thanks -
>>> Manish
>>>
>>>> is there a way we can associate this buffer with the reciever inode
>>>> or write the contents of the buffer to the new inode.
>>>>
>>>>
>>>> On Tue, Jan 6, 2009 at 10:46 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote:
>>>>> On Tue, Jan 6, 2009 at 10:43 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote:
>>>>>> On Tue, Jan 6, 2009 at 10:15 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote:
>>>>>>> On Tue, Jan 6, 2009 at 7:42 PM, rishi agrawal <postrishi@xxxxxxxxx> 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@xxxxxxxxx> wrote:
>>>>>>>>>
>>>>>>>>> On Tue, Jan 6, 2009 at 4:06 PM, Rohit Sharma <imreckless@xxxxxxxxx> 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.
>>>>>
>>>>> I am thinking of remounting ext2 in readonly mode, or i'll change the
>>>>> mount flags to readonly. But i m not sure if internally i can copy the
>>>>> data from one block to other.
>>>>>
>>>>>>
>>>>>> Thanks -
>>>>>> Manish
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Can we do that in kernel space.?
>>>>>>>>>
>>>>>>>>> thanks -
>>>>>>>>> Manish
>>>>>>>>> >
>>>>>>>>> > Is that possible in kernel space.?
>>>>>>>>> > --
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>>>>>>>>> >
>>>>>>>>> --
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>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Regards,
>>>>>>>> Rishi B. Agrawal
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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