On 4/17/12 11:59 PM, Andreas Dilger wrote: ... > Secondly, your test program is not doing random writes to disk, but > rather doing writes at 64kB intervals. There is logic in the > uninitialized extent handling that will write zeros to an entire > extent, rather than create many fragmented uninitialized extents. It > may be possible that you are zeroing out the entire file, and writing > 16x as much data as you expect. > > Cheers, Andreas I don't think the testcase as written is triggering that behavior, though other similar testcases might. In this case the left-over uninit extents are large enough that they don't get zeroed: File size of /mnt/scratch/test is 268435456 (65536 blocks, blocksize 4096) ext logical physical expected length flags 0 0 34816 1 1 1 34817 15 unwritten 2 16 34832 1 3 17 34833 15 unwritten 4 32 34848 1 5 33 34849 15 unwritten ... Good guess though :) -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
