On Fri, Sep 21, 2012 at 05:03:41AM +0800, ching wrote: > AFAIK, the autodefrag will read related extents and mark them dirty, > io niceness should be applicable to the read operation I was hesitant to believe that, but tried it and it's right: $ dd if=/dev/zero bs=4k count=1 seek=15 of=file $ dd if=/dev/zero bs=4k count=1 seek=13 of=file conv=notrunc $ dd if=/dev/zero bs=4k count=1 seek=14 of=file conv=notrunc Filesystem type is: 9123683e File size of file is 65536 (16 blocks, blocksize 4096) ext logical physical expected length flags 0 13 1027 1 1 14 1050 1027 1 2 15 1025 1050 1 eof file: 4 extents found remount with autodefrag: $ dd if=/dev/zero bs=4k count=1 seek=16 of=file conv=notrunc Filesystem type is: 9123683e File size of file is 69632 (17 blocks, blocksize 4096) ext logical physical expected length flags 0 13 1033 4 eof file: 2 extents found david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
