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XFS Preallocate using ALLOCSP

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XFS Preallocate using ALLOCSP

Smit Shah
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
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Re: XFS Preallocate using ALLOCSP

Smit Shah
Ok i did the first part i.e preallocation using xfsctl() by using setresgid().
But still is there some way this option could be incorporated in the fallocate system call.
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
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