Re: XFS metadata CRC errors on zram block device on ppc64le architecture

[Hannes Reinecke]

On 8/4/23 15:42, Christoph Hellwig wrote:
> FYI, I've found an arm64 system with 16k page size support, and while
> I can't reproduce the exact issue, I do see corruption with I/O test
> on zram that don't show on the same system with 4k pages.  I'm trying
> to understand the details at the moment.
For some reason zram run with a logical block size of 4k:

#define ZRAM_LOGICAL_BLOCK_SHIFT 12
#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)

so we'll have sub-page accesses for larger page sizes.
My bet is that the issue goes away if we set the logical block size to 
page size ...

Cheers,

Hannes
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Dr. Hannes Reinecke                Kernel Storage Architect
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