I just got a report of data being marked as incompressible when written with particular blocksizes.
Investigating a bit further, when attempting to compress >= 32k (of all zeroes), I get: [ 8.214090] bcachefs (vdb): zstd error: (efault) -64, src_len 32768 dst_len 32768 [ 8.214713] bcachefs (vdb): zstd error: (efault) -64, src_len 65536 dst_len 65536 [ 8.215349] bcachefs (vdb): zstd error: (efault) -64, src_len 65536 dst_len 65536 [ 8.215432] bcachefs (vdb): zstd error: (efault) -64, src_len 65536 dst_len 65536 bcachefs code that calls zstd: https://evilpiepirate.org/git/bcachefs.git/tree/fs/bcachefs/compress.c?h=bcachefs-testing#n350 -64 appears to be ZSTD_error_memory_allocation, but I get no hits for that grepping, so I'm a bit stuck.
