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authorSami Tolvanen <samitolvanen@google.com>2015-12-03 14:26:30 +0000
committerMike Snitzer <snitzer@redhat.com>2015-12-10 10:39:03 -0500
commita739ff3f543afbb4a041c16cd0182c8e8d366e70 (patch)
tree2613a382283548a1b88e6f2ba589252312d05fff /drivers/md/Kconfig
parentbb4d73ac5e4f0a6c4853f35824f6cb2d396a2f9c (diff)
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dm verity: add support for forward error correction
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>
Diffstat (limited to 'drivers/md/Kconfig')
-rw-r--r--drivers/md/Kconfig12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 1b69359..0a2e727 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -467,6 +467,18 @@ config DM_VERITY
If unsure, say N.
+config DM_VERITY_FEC
+ bool "Verity forward error correction support"
+ depends on DM_VERITY
+ select REED_SOLOMON
+ select REED_SOLOMON_DEC8
+ ---help---
+ Add forward error correction support to dm-verity. This option
+ makes it possible to use pre-generated error correction data to
+ recover from corrupted blocks.
+
+ If unsure, say N.
+
config DM_SWITCH
tristate "Switch target support (EXPERIMENTAL)"
depends on BLK_DEV_DM
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