On Thu, May 25, 2023 at 05:28:55PM -0700, Darrick J. Wong wrote:
> Hi all,
>
> In general, online repair of an indexed record set walks the filesystem
> looking for records. These records are sorted and bulk-loaded into a
> new btree. To make this happen without pinning gigabytes of metadata in
> memory, first create an abstraction ('xfile') of memfd files so that
> kernel code can access paged memory, and then an array abstraction
> ('xfarray') based on xfiles so that online repair can create an array of
> new records without pinning memory.
>
> These two data storage abstractions are critical for repair of space
> metadata -- the memory used is pageable, which helps us avoid pinning
> kernel memory and driving OOM problems; and they are byte-accessible
> enough that we can use them like (very slow and programmatic) memory
> buffers.
>
> Later patchsets will build on this functionality to provide blob storage
> and btrees.
Apart from the need for a struct xfs-mount just for the xfile name
at creation time, this all looks OK.
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Is there any specific test harness for this infrastructure, or is it
just validated by having other functions built on top of it "work
correctly"?
-Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
