Ted / Akira, What's the status of this. I certainly like the ABI much better now than on the previous try. I don't know the ext4 code internally so I can't speak to the implementation quality, but I know this has been floating around for a long time and seems to just be getting better and better. Any chance of it being merged soon? Thanks Greg 2009/5/22 Akira Fujita <a-fujita@xxxxxxxxxxxxx>: > Hi, > > There are the updated patches for ext4 online defrag. > I have addressed the comments that I had got about defrag V1 > (http://marc.info/?l=linux-ext4&m=123329594919001&w=3). > Changes of this version are as follows: > > - Change function name from ext4_defrag_xxx to ext4_mext_xxx > and also change the source file name from defrag.c to move_extent.c. > - Disallow swapfile defrag. > - Support uninitialized extent defrag. > - Disallow data write out for uninitalized extent. > - Call fget() and fput() instead of fget_light() and fput_light() > for module compile. > - Acquire mutex and semaphore of orig and donor inodes by i_ino order. > - Localized semaphore acquisition/release. > - Add ext4_mext_inode_double_lock/unlock() for i_mutex lock/unlock, > since inode_double_lock/unlock() have been removed. > - Replace random printk() with ext4_debug(). > - Some cleanups. > > Ext4 online defrag uses EXT4_IOC_MOVE_EXT ioctl and move_extent structure. > > #define EXT4_IOC_MOVE_EXT _IOWR('f', 15, struct move_extent) > > struct move_extent { > int orig_fd; /* original file descriptor */ > int donor_fd; /* donor file descriptor */ > __u64 orig_start; /* logical start offset in block for orig */ > __u64 donor_start; /* logical start offset in block for donor */ > __u64 len; /* block length to be moved */ > __u64 moved_len; /* moved block length */ > }; > > > Ext4 online defrag is done in the following steps: > (U:User space K:Kernel space) > > 1:U Create donor inode and then call unlink() to it. > > 2:U Allocate contiguous blocks to donor inode with fallocate(). > > 3:U Call the FS_IOC_FIEMAP ioctl to get the extents information of donor inode. > And check the extents of donor inode are less than the defrag target inode's. > > 4:U Call the EXT4_IOC_MOVE_EXT ioctl extent unit. > > 5:K In kernel space, the EXT4_IOC_MOVE_EXT ioctl calls ext4_mext_move_extent() > to exchange the blocks between orig_fd and donor_fd. > Then write the file data of orig_fd to donor_fd. > > 6:U Close donor inode, then it will be deleted. > > Note: More tests may be needed without journal, > so I recommend that e4defrag is run on ext4 with journal. > > Summary of patch series: > * The patch can be applied to the ext4 patch queue (2.6.30-rc6). > > [PATCH 1/3] Add EXT4_IOC_DEFRAG ioctl and defrag functions > - Add EXT4_IOC_DEFRAG ioctl and related functions. > - For each page, exchange the extents between original inode > and donor inode, and then write the file data of > the original inode to donor inode. > > [PATCH 2/3] Ext4 online defrag command > - Usage is as follows: > - Defrag for a single file. > # e4defrag file, directory, device > - Check the file fragments on ext4. > # e4defrag -c file, directory, device > > [PATCH 3/3] Manpage of e4defrag > - Ext4 online defrag command manpage > # nroff -man e4defrag.8 > > Best regards, > Akira Fujita > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Greg Freemyer Head of EDD Tape Extraction and Processing team Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
