On Wed, Jan 7, 2009 at 12:44 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote: > On Wed, Jan 7, 2009 at 12:17 PM, Sandeep K Sinha > <sandeepksinha@xxxxxxxxx> wrote: >> Ok, Let me rephrase what rohit is exactly trying to question. >> >> There is an inode X which has say some N number of data blocks. >> Now, through his own kernel module and some changes to the file system, >> he wants to create a new inode Y in the FS and physically copy all the >> data from the old inode to the new inode. > > Errr....... I must be missing something...... For this why do you need > to copy the data blocks ? if you just copy the old inode to new inode, > you have already copied the direct and indirect block pointers right ? > That will not take much time, and now if you free the old inode, you > have virtually changed the ownership of old blocks to the new inode. > The problem is not replacing the inode, i want to physically move the data. That means if inode X and its data blocks are in block group 1, and new inode is in block group 100 then i will allocate data blocks in block group 100 and copy the data from inode X to inode Y. So i will be able to physically relocate a file, and change the directory entry to contain inode Y. > The problems i can see with this approach is that if the new inode is > not in the same block group as old inode, you have *kind of broken* > the ext2's intelligence of allocating the blocks in the same block > group. > > CMIIW . btw this thread is interesting :-) Yes its interesting. :-) > I haven't actually broken ext2's intelligence completely, i have only put restrictions in allocation of inode and data blocks. And it works fine with existing optimizations. And the major issue is relocating files between different block group range. > Thanks - > Manish. > >> >> And release the old inode and its data blocks and update the dentry >> with the new inode number. >> PS: The file system remains completely frozen in this time. >> >> >> On Wed, Jan 7, 2009 at 4:02 AM, Om <om.turyx@xxxxxxxxx> wrote: >>> Erik Mouw wrote: >>>> >>>> On Tue, 6 Jan 2009 23:16:14 +0530 "Rohit Sharma" <imreckless@xxxxxxxxx> >>>> wrote: >>>>> >>>>> On Tue, Jan 6, 2009 at 11:09 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> >>>>> wrote: >>>>>> >>>>>> 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. >>>> >>>> Hardly more efficient. Your main bottleneck will be IO from/to the >>>> device. If you are worried about copying between kernel and userland, >>>> you could use the tee(2) and splice(2) system calls. They are relatively >>>> new, so your system might not yet have manual pages for them. In that >>>> case, see http://linux.die.net/man/2/tee and >>>> http://linux.die.net/man/2/splice . >>> >>> Hm.. that is pretty enlightening... >>> Thanks, >>> Om. >>> >>> >>> -- >>> To unsubscribe from this list: send an email with >>> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx >>> Please read the FAQ at http://kernelnewbies.org/FAQ >>> >>> >> >> >> >> -- >> Regards, >> Sandeep. >> >> >> >> >> >> >> "To learn is to change. Education is a process that changes the learner." >> >> -- >> To unsubscribe from this list: send an email with >> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx >> Please read the FAQ at http://kernelnewbies.org/FAQ >> >> > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx > Please read the FAQ at http://kernelnewbies.org/FAQ > > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
