lib-index: tail_offset wasn't updated as often as it should have been.

ctx->last_tail_offset was being increased for every non-external transaction
and at the end we checked if head was larger than it. This logic didn't
really make any sense, since non-external transactions specifically were
supposed to update the tail_offset.

diff --git a/src/lib-index/mail-index-sync.c b/src/lib-index/mail-index-sync.c
index e8d43ae2aa813b5fc4d3a8e47096bd1d4daeeff6..f93c5490e846df1e83b78eee0de5682d61b0d606 100644 (file)
--- a/src/lib-index/mail-index-sync.c
+++ b/src/lib-index/mail-index-sync.c
@@ -22,7 +22,6 @@ struct mail_index_sync_ctx {
 
        ARRAY(struct mail_index_sync_list) sync_list;
        uint32_t next_uid;
-       uint32_t last_tail_seq, last_tail_offset;
 
        unsigned int no_warning:1;
        unsigned int seen_nonexternal_transactions:1;
@@ -164,20 +163,6 @@ static void mail_index_sync_add_dirty_updates(struct mail_index_sync_ctx *ctx)
        }
 }
 
-static void
-mail_index_sync_update_mailbox_pos(struct mail_index_sync_ctx *ctx)
-{
-       uint32_t seq;
-       uoff_t offset;
-
-       mail_transaction_log_view_get_prev_pos(ctx->view->log_view,
-                                              &seq, &offset);
-
-       ctx->seen_nonexternal_transactions = TRUE;
-       ctx->last_tail_seq = seq;
-       ctx->last_tail_offset = offset + ctx->hdr->size + sizeof(*ctx->hdr);
-}
-
 static int
 mail_index_sync_read_and_sort(struct mail_index_sync_ctx *ctx)
 {
@@ -203,8 +188,14 @@ mail_index_sync_read_and_sort(struct mail_index_sync_ctx *ctx)
                        continue;
 
                T_BEGIN {
-                       if (mail_index_sync_add_transaction(ctx))
-                               mail_index_sync_update_mailbox_pos(ctx);
+                       if (mail_index_sync_add_transaction(ctx)) {
+                               /* update tail_offset if needed */
+                               ctx->seen_nonexternal_transactions = TRUE;
+                       } else {
+                               /* this is an internal change. we don't
+                                  necessarily need to update tail_offset, so
+                                  avoid the extra write caused by it. */
+                       }
                } T_END;
        }
 
@@ -436,8 +427,6 @@ mail_index_sync_begin_to2(struct mail_index *index,
 
        ctx = i_new(struct mail_index_sync_ctx, 1);
        ctx->index = index;
-       ctx->last_tail_seq = hdr->log_file_seq;
-       ctx->last_tail_offset = hdr->log_file_tail_offset;
        ctx->flags = flags;
 
        ctx->view = mail_index_view_open(index);
@@ -764,6 +753,7 @@ static void mail_index_sync_end(struct mail_index_sync_ctx **_ctx)
 static void
 mail_index_sync_update_mailbox_offset(struct mail_index_sync_ctx *ctx)
 {
+       const struct mail_index_header *hdr = &ctx->index->map->hdr;
        uint32_t seq;
        uoff_t offset;
 
@@ -785,7 +775,7 @@ mail_index_sync_update_mailbox_offset(struct mail_index_sync_ctx *ctx)
           external, because that wouldn't change effective the tail offset.
           except e.g. mdbox map requires this to happen, so do it
           optionally. */
-       if ((ctx->last_tail_seq != seq || ctx->last_tail_offset < offset) &&
+       if ((hdr->log_file_seq != seq || hdr->log_file_tail_offset < offset) &&
            (ctx->seen_nonexternal_transactions ||
             (ctx->flags & MAIL_INDEX_SYNC_FLAG_UPDATE_TAIL_OFFSET) != 0)) {
                ctx->ext_trans->log_updates = TRUE;