On Mon, 2021-10-25 at 11:42 +0200, Lukas Czerner wrote: > On Sat, Oct 23, 2021 at 12:24:40PM +0200, Laurent GUERBY wrote: > > > > I did end up creating dummy files to fill the filesystem and then > > removing them, but this is far less efficient than what a > > filesystem > > tool could do. > > Yeah, that's bad. The information is stored in the buddy cache in > memory > and AFAIK is only dropped on unmount. I'll have to think about how to > clear either the cache or selectively just the flag. > > What would be more convenient way of doing this for you, -o remount, > or > using let's say tune2fs ? I am not promising anything yet, but I'll > think > about how to implement it. > > > Meanwhile other than umount/mount, or actually writing to the dummy > files, > you can try to use fallocate to allocate all the remaining space in > the > file system and subsequently removing it. That should be more > efficient, > but don't forget to sync after remove to make sure the space is > released > before you call fstrim. Thanks for the advice on fallocate! It does work and is very fast. I would prefer a specific tune2fs as remount forcing this TRIM cache clearing behaviour might be unwanted. > You could also force fsck on ro file system and use -E discard to > trim the > free space but I can't say I recommend it. Thanks again for your help, Sincerely, Laurent
