On Thu, Apr 23, 2020 at 1:06 PM Marek Behun <marek.behun@xxxxxx> wrote: > > On Thu, 23 Apr 2020 12:51:32 +0100 > Filipe Manana <fdmanana@xxxxxxxxx> wrote: > > > There's nothing in btrfs that converts a sequence of zeroes > > automatically to a hole. > > > > It always has to be done by user space, either by writes that leave > > holes intentionally (e.g. create file, write 64K to offset 0, write 4K > > to offset 128, leaves a hole from range 64K to 128K) or by hole > > punching through fallocate(). > > Thanks for this information. If you ever come to Prague, let me know, > we can have a beer :D Noted! (Through it will be a long while until travel is allowed and safe) Another case I forgot is a hole created by truncation - truncate a file to a larger size, then you get a hole for the range that goes from the old file size to the new file size. -- Filipe David Manana, “Whether you think you can, or you think you can't — you're right.”
