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Centralize canonical SnapRAID block hashing semantics

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This commit is contained in:
Andrea Mazzoleni 2026-08-30 23:09:29 +02:00
parent 0ab885d8e5
commit 1a5b5728d2
7 changed files with 87 additions and 33 deletions
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17
cmdline/check.c
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@ -270,11 +270,11 @@ static int blockcmp(struct snapraid_state* state, int rehash, struct snapraid_bl
{
unsigned char hash[HASH_MAX];
/* now compute the hash of the valid part */
/* compute the hash according to the block-hash semantics */
if (rehash) {
memhash(state->prevhash, state->prevhashseed, hash, buffer, pos_size);
memhash_block(state->prevhash, state->prevhashseed, hash, buffer, pos_size, state->block_size);
} else {
memhash(state->hash, state->hashseed, hash, buffer, pos_size);
memhash_block(state->hash, state->hashseed, hash, buffer, pos_size, state->block_size);
}
/* compare the hash */
@ -283,10 +283,11 @@ static int blockcmp(struct snapraid_state* state, int rehash, struct snapraid_bl
}
/*
* The hash covers only the logical bytes belonging to the file, while RAID
* Legacy hashes cover only the logical bytes belonging to the file, while RAID
* operates on the complete zero-padded block. Verify the padding separately:
* otherwise corruption confined to the reconstructed tail could pass the hash
* check and later produce incorrect parity.
* otherwise corruption confined to the reconstructed tail could pass a legacy
* hash check and later produce incorrect parity. This is redundant for MuseAir,
* but also makes the canonical-block invariant explicit.
*/
if (pos_size < state->block_size) {
if (memcmp(buffer + pos_size, buffer_zero + pos_size, state->block_size - pos_size) != 0) {
@ -1977,9 +1978,9 @@ static int state_check_process(struct snapraid_state* state, int fix, struct sna
/* compute the hash of the block just read */
if (rehash) {
memhash(state->prevhash, state->prevhashseed, hash, buffer[j], read_size);
memhash_block(state->prevhash, state->prevhashseed, hash, buffer[j], read_size, state->block_size);
} else {
memhash(state->hash, state->hashseed, hash, buffer[j], read_size);
memhash_block(state->hash, state->hashseed, hash, buffer[j], read_size, state->block_size);
}
/* compare the hash */