journal: remember last direction of search and keep offset cache

The fields in JournalFile are moved around to avoid wasting
7 bytes because of alignment.

2 files changed, 16 insertions, 13 deletions

diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h
index 7b1cd4285..5cc2c2d28 100644
--- a/src/journal/journal-file.h
+++ b/src/journal/journal-file.h
@@ -42,10 +42,14 @@ typedef struct JournalMetrics {
         uint64_t keep_free;
 } JournalMetrics;
 
+typedef enum direction {
+        DIRECTION_UP,
+        DIRECTION_DOWN
+} direction_t;
+
 typedef struct JournalFile {
         int fd;
-        char *path;
-        struct stat last_stat;
+
         mode_t mode;
 
         int flags;
@@ -56,6 +60,11 @@ typedef struct JournalFile {
 
         bool tail_entry_monotonic_valid;
 
+        direction_t last_direction;
+
+        char *path;
+        struct stat last_stat;
+
         Header *header;
         HashItem *data_hash_table;
         HashItem *field_hash_table;
@@ -90,11 +99,6 @@ typedef struct JournalFile {
 #endif
 } JournalFile;
 
-typedef enum direction {
-        DIRECTION_UP,
-        DIRECTION_DOWN
-} direction_t;
-
 int journal_file_open(
                 const char *fname,
                 int flags,
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 3aa9ed4b3..4c4cc2d21 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -102,7 +102,8 @@ static void init_location(Location *l, LocationType type, JournalFile *f, Object
         l->seqnum_set = l->realtime_set = l->monotonic_set = l->xor_hash_set = true;
 }
 
-static void set_location(sd_journal *j, LocationType type, JournalFile *f, Object *o, uint64_t offset) {
+static void set_location(sd_journal *j, LocationType type, JournalFile *f, Object *o,
+                         direction_t direction, uint64_t offset) {
         assert(j);
         assert(type == LOCATION_DISCRETE || type == LOCATION_SEEK);
         assert(f);
@@ -110,12 +111,10 @@ static void set_location(sd_journal *j, LocationType type, JournalFile *f, Objec
 
         init_location(&j->current_location, type, f, o);
 
-        if (j->current_file)
-                j->current_file->current_offset = 0;
-
         j->current_file = f;
         j->current_field = 0;
 
+        f->last_direction = direction;
         f->current_offset = offset;
 }
 
@@ -811,7 +810,7 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc
         assert(j);
         assert(f);
 
-        if (f->current_offset > 0) {
+        if (f->last_direction == direction && f->current_offset > 0) {
                 cp = f->current_offset;
 
                 r = journal_file_move_to_object(f, OBJECT_ENTRY, cp, &c);
@@ -908,7 +907,7 @@ static int real_journal_next(sd_journal *j, direction_t direction) {
         if (r < 0)
                 return r;
 
-        set_location(j, LOCATION_DISCRETE, new_file, o, new_offset);
+        set_location(j, LOCATION_DISCRETE, new_file, o, direction, new_offset);
 
         return 1;
 }