From: "Rohit Sharma" Subject: Re: Copying Data Blocks Date: Tue, 6 Jan 2009 22:55:23 +0530 Message-ID: <2d08ef090901060925p685506abkdc722c4099b485c7@mail.gmail.com> References: <2d08ef090901060236p46d4d396x797e4bceb24a2a34@mail.gmail.com> <5feb302e0901060612p4e114953pb6e297778aa7c0a4@mail.gmail.com> <2d08ef090901060845t85ac2b0i11c684a09d930608@mail.gmail.com> <2d08ef090901060916y4c49884dy4b44d6354b11ebb8@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 mail-gx0-f16.google.com ([209.85.217.16]:56230 "EHLO mail-gx0-f16.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751064AbZAFRZZ (ORCPT ); Tue, 6 Jan 2009 12:25:25 -0500 Received: by gxk9 with SMTP id 9so5772816gxk.8 for ; Tue, 06 Jan 2009 09:25:23 -0800 (PST) In-Reply-To: <2d08ef090901060916y4c49884dy4b44d6354b11ebb8@mail.gmail.com> Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: 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, 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 wrote: > 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 >>>> >>>> >>> >> >