[patch] rm can have undesired side-effects

Craig Boston craig at tobuj.gank.org
Fri Nov 3 05:02:59 UTC 2006

On Thu, Nov 02, 2006 at 10:52:19AM +0000, Jan Grant wrote:
> This is, I reckon, the only sensible suggestion thus far: if the FS 
> doesn't help you then you are implicitly depending on the FS 
> implementation to ensure you are writing over the original data blocks 
> anyway.

And you may very well not be.  If the underlying FS is say for example
journaled or snapshotted, your new data blocks may go to a completely
different part of the disk.  For UFS today -P may work most of the time,
assuming no snapshots or other events moving the file.  With gjournal
and gvirtstor coming who knows if that will remain true.

That doesn't even take into account things like unionfs or other VFS

If writing zeros or whatever to a file (that may or may not overwrite
the previous contents on disk) is really what you want to do, dd works
just fine for the task.

/me votes for removing the -P misfeature altogether


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