cluster/afr: Add the "diff" self-heal algorithm.

The "diff" self-heal algorithm works as follows:

  For each block:
    Compute MD5 checksum on source and all sinks
    If checksum on a sink differs from source:
      Read block from source and write to sinks

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-algorithm.h b/xlators/cluster/afr/src/afr-self-heal-algorithm.h
index 646fd2ee7c1..8998ce8883d 100644
--- a/xlators/cluster/afr/src/afr-self-heal-algorithm.h
+++ b/xlators/cluster/afr/src/afr-self-heal-algorithm.h
@@ -29,6 +29,14 @@ struct afr_sh_algorithm {
         afr_sh_algo_fn fn;
 };
 
-struct afr_sh_algorithm afr_self_heal_algorithms[1];
+struct afr_sh_algorithm afr_self_heal_algorithms[2];
+
+typedef struct {
+        uint8_t *checksum;     /* array of MD5 checksums for each child
+                                  Each checksum is MD5_DIGEST_LEN bytes long */
+
+        unsigned char *write_needed;
+        size_t block_size;
+} afr_sh_algo_diff_private_t;
 
 #endif /* __AFR_SELF_HEAL_ALGORITHM_H__ */