Merge "libfec: remove verity validation cache"

3 files changed, 14 insertions, 55 deletions

diff --git a/libfec/fec_private.h b/libfec/fec_private.h
index 21758990..bde30bd8 100644
--- a/libfec/fec_private.h
+++ b/libfec/fec_private.h
@@ -19,7 +19,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <list>
 #include <memory>
 #include <new>
 #include <pthread.h>
@@ -28,7 +27,6 @@
 #include <string.h>
 #include <sys/syscall.h>
 #include <unistd.h>
-#include <unordered_map>
 #include <vector>
 
 #include <utils/Compat.h>
@@ -103,8 +101,6 @@ struct fec_handle {
     int flags; /* additional flags passed to fec_open */
     int mode; /* mode for open(2) */
     pthread_mutex_t mutex;
-    std::list<verity_block_info> lru;
-    std::unordered_map<uint64_t, std::list<verity_block_info>::iterator> cache;
     uint64_t errors;
     uint64_t data_size;
     uint64_t pos;
@@ -131,8 +127,8 @@ extern uint64_t verity_get_size(uint64_t file_size, uint32_t *verity_levels,
 
 extern int verity_parse_header(fec_handle *f, uint64_t offset);
 
-extern bool verity_check_block(fec_handle *f, uint64_t index,
-        const uint8_t *expected, const uint8_t *block);
+extern bool verity_check_block(fec_handle *f, const uint8_t *expected,
+        const uint8_t *block);
 
 /* helper macros */
 #ifndef unlikely
diff --git a/libfec/fec_read.cpp b/libfec/fec_read.cpp
index 68ea410e..3736e337 100644
--- a/libfec/fec_read.cpp
+++ b/libfec/fec_read.cpp
@@ -77,7 +77,7 @@ static inline bool is_erasure(fec_handle *f, uint64_t offset,
 
     uint64_t n = offset / FEC_BLOCKSIZE;
 
-    return !verity_check_block(f, n, &f->verity.hash[n * SHA256_DIGEST_LENGTH],
+    return !verity_check_block(f, &f->verity.hash[n * SHA256_DIGEST_LENGTH],
                 data);
 }
 
@@ -327,7 +327,7 @@ static ssize_t verity_read(fec_handle *f, uint8_t *dest, size_t count,
             return -1;
         }
 
-        if (likely(verity_check_block(f, curr, hash, data))) {
+        if (likely(verity_check_block(f, hash, data))) {
             goto valid;
         }
 
@@ -352,14 +352,14 @@ static ssize_t verity_read(fec_handle *f, uint8_t *dest, size_t count,
            erasure locations is slower */
         if (__ecc_read(f, rs.get(), data, curr_offset, false, ecc_data.get(),
                 errors) == FEC_BLOCKSIZE &&
-            verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+            verity_check_block(f, hash, data)) {
             goto corrected;
         }
 
         /* try to correct with erasures */
         if (__ecc_read(f, rs.get(), data, curr_offset, true, ecc_data.get(),
                 errors) == FEC_BLOCKSIZE &&
-            verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+            verity_check_block(f, hash, data)) {
             goto corrected;
         }
 
diff --git a/libfec/fec_verity.cpp b/libfec/fec_verity.cpp
index 7537530b..8de25efc 100644
--- a/libfec/fec_verity.cpp
+++ b/libfec/fec_verity.cpp
@@ -136,30 +136,12 @@ static inline int verity_hash(fec_handle *f, const uint8_t *block,
 }
 
 /* computes a verity hash for FEC_BLOCKSIZE bytes from buffer `block' and
-   compres it to the expected value in `expected'; if `index' has a value
-   different from `VERITY_NO_CACHE', uses `f->cache' to cache the results */
-bool verity_check_block(fec_handle *f, uint64_t index, const uint8_t *expected,
+   compares it to the expected value in `expected' */
+bool verity_check_block(fec_handle *f, const uint8_t *expected,
         const uint8_t *block)
 {
     check(f);
-
-    if (index != VERITY_NO_CACHE) {
-        pthread_mutex_lock(&f->mutex);
-        auto cached = f->cache.find(index);
-
-        if (cached != f->cache.end()) {
-            verity_block_info vbi = *(cached->second);
-
-            f->lru.erase(cached->second);
-            f->lru.push_front(vbi);
-            f->cache[index] = f->lru.begin();
-
-            pthread_mutex_unlock(&f->mutex);
-            return vbi.valid;
-        }
-
-        pthread_mutex_unlock(&f->mutex);
-    }
+    check(block);
 
     uint8_t hash[SHA256_DIGEST_LENGTH];
 
@@ -169,26 +151,7 @@ bool verity_check_block(fec_handle *f, uint64_t index, const uint8_t *expected,
     }
 
     check(expected);
-    bool valid = !memcmp(expected, hash, SHA256_DIGEST_LENGTH);
-
-    if (index != VERITY_NO_CACHE) {
-        pthread_mutex_lock(&f->mutex);
-
-        verity_block_info vbi;
-        vbi.index = index;
-        vbi.valid = valid;
-
-        if (f->lru.size() >= VERITY_CACHE_BLOCKS) {
-            f->cache.erase(f->lru.rbegin()->index);
-            f->lru.pop_back();
-        }
-
-        f->lru.push_front(vbi);
-        f->cache[index] = f->lru.begin();
-        pthread_mutex_unlock(&f->mutex);
-    }
-
-    return valid;
+    return !memcmp(expected, hash, SHA256_DIGEST_LENGTH);
 }
 
 /* reads a verity hash and the corresponding data block using error correction,
@@ -244,10 +207,10 @@ static int verify_tree(fec_handle *f, const uint8_t *root)
 
     /* validate the root hash */
     if (!raw_pread(f, data, FEC_BLOCKSIZE, hash_offset) ||
-            !verity_check_block(f, VERITY_NO_CACHE, root, data)) {
+            !verity_check_block(f, root, data)) {
         /* try to correct */
         if (!ecc_read_hashes(f, 0, NULL, hash_offset, data) ||
-                !verity_check_block(f, VERITY_NO_CACHE, root, data)) {
+                !verity_check_block(f, root, data)) {
             error("root hash invalid");
             return -1;
         } else if (f->mode & O_RDWR &&
@@ -312,12 +275,12 @@ static int verify_tree(fec_handle *f, const uint8_t *root)
                 return -1;
             }
 
-            if (!verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+            if (!verity_check_block(f, hash, data)) {
                 /* try to correct */
                 if (!ecc_read_hashes(f,
                         hash_offset + j * SHA256_DIGEST_LENGTH, hash,
                         data_offset + j * FEC_BLOCKSIZE, data) ||
-                    !verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+                    !verity_check_block(f, hash, data)) {
                     error("invalid hash tree: hash_offset %" PRIu64 ", "
                         "data_offset %" PRIu64 ", block %u",
                         hash_offset, data_offset, j);