XFS Preallocate using ALLOCSP

[Eric Sandeen]

Smit Shah wrote:
> Hi, 
> 
> I wanted to preallocate the file using the ALLOCSP so that the preallocated
> space is zeroed out. Hence i used the xfsctl but the problem is that i
> cannot execute  it as a non-root user.  So i tried using fallocate but when
> i saw the xfs implementation of kernel it uses the RESVP cmd and  since the
> unwritten flag is set i am assuming that the performance of writing to the
> preallocated space will suffer because of the metadata updates. So is there
> a way to preallocate using ALLOCSP as a non-root user or else i would be
> required to modify the kernel ??
> 
> TIA, 
> Smit 

ALLOCSP simply writes 0s to a file.... you may as well do it using posix
calls, as a normal user, I think.

-Eric