Hi there,

I have a large ext 4 filesystem (nearly 2 Terabytes) that is locally mounted on PC A and mounted over NFS on PC B. When I delte files while being logged in on PC B, the free disk space is not or nearly not changing.

Example: I delete 90 GB, but free space increments by only 5 GB. Usually, I do the delete in a terminal using rm -rf. No GUI application, no Trash folder. The only way to get the free space increment was (up to today) the following procedure:

1. umount it on PC B
2. stop the NFS server on PC A
3. umount it on PC A
4. optionally do a filesystem check
5. re-mount it on PC A
6. restart the NFS server
7. re-mount it on PC B

Note: In these cases, the umount takes unnormally long (sometimes over 30 seconds).

First, I thought ist was a problem with my filesystem. But today, I realized that I always do the delete over NFS. So, I made the crosscheck. This time, I logged in on PC A and deleted the files locally. Deleted 43 GB, free space increment: 43 GB.

Well, the problem seems solved.

But still, I would like to know what the problem exactly is.

Why and by whom is the disk space still locked, even if I umount the partition on PC B and stop the NFS server on PC A ?
Note: I use the nfs kernel server, if this makes a difference.
My System is currently Ubuntu 12.04. But I experienced this weird behaviour already on my old system with Ubuntu 10.04.

Additional info: It looks like it only happens when deleting many gigabytes at once.