From: "Rohit Sharma" Subject: Re: Copying Data Blocks Date: Tue, 6 Jan 2009 22:46:47 +0530 Message-ID: <2d08ef090901060916y4c49884dy4b44d6354b11ebb8@mail.gmail.com> References: <2d08ef090901060236p46d4d396x797e4bceb24a2a34@mail.gmail.com> <5feb302e0901060612p4e114953pb6e297778aa7c0a4@mail.gmail.com> <2d08ef090901060845t85ac2b0i11c684a09d930608@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "rishi agrawal" , ext4 , Kernelnewbies To: "Manish Katiyar" Return-path: Received: from an-out-0708.google.com ([209.85.132.240]:16314 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751848AbZAFRQt (ORCPT ); Tue, 6 Jan 2009 12:16:49 -0500 Received: by an-out-0708.google.com with SMTP id d40so2555395and.1 for ; Tue, 06 Jan 2009 09:16:47 -0800 (PST) In-Reply-To: Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jan 6, 2009 at 10:43 PM, Manish Katiyar wrote: > On Tue, Jan 6, 2009 at 10:15 PM, Rohit Sharma wrote: >> On Tue, Jan 6, 2009 at 7:42 PM, rishi agrawal 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 wrote: >>>> >>>> On Tue, Jan 6, 2009 at 4:06 PM, Rohit Sharma 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.? >>>> > -- >>>> > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >>>> > the body of a message to majordomo@vger.kernel.org >>>> > More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> > >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >>> >>> >>> -- >>> Regards, >>> Rishi B. Agrawal >>> >>> >> >