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path: root/drivers/md/dm-verity-fec.c
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2016-07-01dm verity fec: fix block calculationSami Tolvanen
do_div was replaced with div64_u64 at some point, causing a bug with block calculation due to incompatible semantics of the two functions. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Cc: stable@vger.kernel.org # v4.5+ Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: rename target's per_bio_data_size to per_io_data_sizeMike Snitzer
Request-based DM will also make use of per_bio_data_size. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10dm verity: add ignore_zero_blocks featureSami Tolvanen
If ignore_zero_blocks is enabled dm-verity will return zeroes for blocks matching a zero hash without validating the content. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10dm verity: add support for forward error correctionSami Tolvanen
Add support for correcting corrupted blocks using Reed-Solomon. This code uses RS(255, N) interleaved across data and hash blocks. Each error-correcting block covers N bytes evenly distributed across the combined total data, so that each byte is a maximum distance away from the others. This makes it possible to recover from several consecutive corrupted blocks with relatively small space overhead. In addition, using verity hashes to locate erasures nearly doubles the effectiveness of error correction. Being able to detect corrupted blocks also improves performance, because only corrupted blocks need to corrected. For a 2 GiB partition, RS(255, 253) (two parity bytes for each 253-byte block) can correct up to 16 MiB of consecutive corrupted blocks if erasures can be located, and 8 MiB if they cannot, with 16 MiB space overhead. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>