3 files changed, 43 insertions, 11 deletions

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index be6a5522fa..f7815b2796 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -656,13 +656,16 @@ static int journal_file_setup_field_hash_table(JournalFile *f) {
         return 0;
 }
 
-static int journal_file_map_data_hash_table(JournalFile *f) {
+int journal_file_map_data_hash_table(JournalFile *f) {
         uint64_t s, p;
         void *t;
         int r;
 
         assert(f);
 
+        if (f->data_hash_table)
+                return 0;
+
         p = le64toh(f->header->data_hash_table_offset);
         s = le64toh(f->header->data_hash_table_size);
 
@@ -678,13 +681,16 @@ static int journal_file_map_data_hash_table(JournalFile *f) {
         return 0;
 }
 
-static int journal_file_map_field_hash_table(JournalFile *f) {
+int journal_file_map_field_hash_table(JournalFile *f) {
         uint64_t s, p;
         void *t;
         int r;
 
         assert(f);
 
+        if (f->field_hash_table)
+                return 0;
+
         p = le64toh(f->header->field_hash_table_offset);
         s = le64toh(f->header->field_hash_table_size);
 
@@ -803,10 +809,18 @@ int journal_file_find_field_object_with_hash(
         assert(f);
         assert(field && size > 0);
 
+        /* If the field hash table is empty, we can't find anything */
+        if (le64toh(f->header->field_hash_table_size) <= 0)
+                return 0;
+
+        /* Map the field hash table, if it isn't mapped yet. */
+        r = journal_file_map_field_hash_table(f);
+        if (r < 0)
+                return r;
+
         osize = offsetof(Object, field.payload) + size;
 
         m = le64toh(f->header->field_hash_table_size) / sizeof(HashItem);
-
         if (m <= 0)
                 return -EBADMSG;
 
@@ -866,6 +880,15 @@ int journal_file_find_data_object_with_hash(
         assert(f);
         assert(data || size == 0);
 
+        /* If there's no data hash table, then there's no entry. */
+        if (le64toh(f->header->data_hash_table_size) <= 0)
+                return 0;
+
+        /* Map the data hash table, if it isn't mapped yet. */
+        r = journal_file_map_data_hash_table(f);
+        if (r < 0)
+                return r;
+
         osize = offsetof(Object, data.payload) + size;
 
         m = le64toh(f->header->data_hash_table_size) / sizeof(HashItem);
@@ -2731,14 +2754,6 @@ int journal_file_open(
 #endif
         }
 
-        r = journal_file_map_field_hash_table(f);
-        if (r < 0)
-                goto fail;
-
-        r = journal_file_map_data_hash_table(f);
-        if (r < 0)
-                goto fail;
-
         if (mmap_cache_got_sigbus(f->mmap, f->fd)) {
                 r = -EIO;
                 goto fail;
diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h
index 403c8f760c..e92b75eabe 100644
--- a/src/journal/journal-file.h
+++ b/src/journal/journal-file.h
@@ -229,3 +229,6 @@ int journal_file_get_cutoff_realtime_usec(JournalFile *f, usec_t *from, usec_t *
 int journal_file_get_cutoff_monotonic_usec(JournalFile *f, sd_id128_t boot, usec_t *from, usec_t *to);
 
 bool journal_file_rotate_suggested(JournalFile *f, usec_t max_file_usec);
+
+int journal_file_map_data_hash_table(JournalFile *f);
+int journal_file_map_field_hash_table(JournalFile *f);
diff --git a/src/journal/journal-verify.c b/src/journal/journal-verify.c
index cf5be1f86a..7d68149cd4 100644
--- a/src/journal/journal-verify.c
+++ b/src/journal/journal-verify.c
@@ -590,6 +590,13 @@ static int verify_hash_table(
         assert(last_usec);
 
         n = le64toh(f->header->data_hash_table_size) / sizeof(HashItem);
+        if (n <= 0)
+                return 0;
+
+        r = journal_file_map_data_hash_table(f);
+        if (r < 0)
+                return log_error_errno(r, "Failed to map data hash table: %m");
+
         for (i = 0; i < n; i++) {
                 uint64_t last = 0, p;
 
@@ -647,6 +654,13 @@ static int data_object_in_hash_table(JournalFile *f, uint64_t hash, uint64_t p)
         assert(f);
 
         n = le64toh(f->header->data_hash_table_size) / sizeof(HashItem);
+        if (n <= 0)
+                return 0;
+
+        r = journal_file_map_data_hash_table(f);
+        if (r < 0)
+                return log_error_errno(r, "Failed to map data hash table: %m");
+
         h = hash % n;
 
         q = le64toh(f->data_hash_table[h].head_hash_offset);