On Mon, Feb 17, 2014 at 04:08:17PM +0100, Lukas Czerner wrote: > Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same > functionality as xfs ioctl XFS_IOC_ZERO_RANGE. > > It can be used to convert a range of file to zeros preferably without > issuing data IO. Blocks should be preallocated for the regions that span > holes in the file, and the entire range is preferable converted to > unwritten extents - even though file system may choose to zero out the > extent or do whatever which will result in reading zeros from the range > while the range remains allocated for the file. > > This can be also used to preallocate blocks past EOF in the same way as > with fallocate. Flag FALLOC_FL_KEEP_SIZE which should cause the inode > size to remain the same. > > You can test this feature yourself using xfstests, of fallocate(1) however > you'll need patches for util_linux, xfsprogs and xfstests which you > can find here: > > http://people.redhat.com/lczerner/zero_range/ > > I'll post the patches after we agree and merge the kernel functionality. > > I tested this mostly with a subset of xfstests using fsx and fsstress and > even with new generic/290 which is just a copy of xfs/290 usinz fzero > command for xfs_io instead of zero (which uses ioctl). I was testing on > x86_64 and ppc64 with block sizes of 1024, 2048 and 4096. You also want to convert xfs/242 to be a generic test - it uses the _generic_test_punch helper to test all the corner cases across different extent type transitions. > ./check generic/076 generic/232 generic/013 generic/070 generic/269 generic/083 generic/117 generic/068 generic/231 generic/127 generic/091 generic/075 generic/112 generic/263 generic/091 generic/075 generic/256 generic/255 generic/316 generic/300 generic/290; > > Note that there is a work in progress on FALLOC_FL_COLLAPSE_RANGE which > touches the same area as this pach set does, so we should figure out > which one should go first and modify the other on top of it. I was going to push the FALLOC_FL_COLLAPSE_RANGE stuff through the XFS tree once it was done - perhaps you and Namjae can get together and work out which order the patch series should go. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
