From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Thu, 26 Mar 2020 14:44:26 +0000 (+0200)
Subject: lib-index: If cache file is compressed during transaction, discard only flushed records
X-Git-Tag: 2.3.11.2~424
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7647aefc81fd9576741c8155014edafe4697dec5;p=thirdparty%2Fdovecot%2Fcore.git

lib-index: If cache file is compressed during transaction, discard only flushed records

Cache records that are still in memory can be written to the new file.
---

diff --git a/src/lib-index/mail-cache-decisions.c b/src/lib-index/mail-cache-decisions.c
index 936fa0033d..953172ec9e 100644
--- a/src/lib-index/mail-cache-decisions.c
+++ b/src/lib-index/mail-cache-decisions.c
@@ -134,7 +134,7 @@ void mail_cache_decision_add(struct mail_cache_view *view, uint32_t seq,
 
 	i_assert(field < cache->fields_count);
 
-	if (MAIL_CACHE_IS_UNUSABLE(cache) || view->no_decision_updates)
+	if (view->no_decision_updates)
 		return;
 
 	if (cache->fields[field].field.decision != MAIL_CACHE_DECISION_NO) {
diff --git a/src/lib-index/mail-cache-transaction.c b/src/lib-index/mail-cache-transaction.c
index d24ca3ed2f..383bfbce8a 100644
--- a/src/lib-index/mail-cache-transaction.c
+++ b/src/lib-index/mail-cache-transaction.c
@@ -200,7 +200,9 @@ mail_cache_transaction_compress(struct mail_cache_transaction_ctx *ctx)
 			mail_cache_compress_unlock(&lock);
 	}
 	mail_index_view_close(&view);
-	mail_cache_transaction_reset(ctx);
+	/* already written cache records must be forgotten, but records in
+	   memory can still be written to the new cache file */
+	mail_cache_transaction_forget_flushed(ctx);
 	return ret;
 }
 
@@ -295,10 +297,10 @@ static int mail_cache_transaction_lock(struct mail_cache_transaction_ctx *ctx)
 	if (ctx->cache_file_seq == 0)
 		ctx->cache_file_seq = cache->hdr->file_seq;
 	else if (ctx->cache_file_seq != cache->hdr->file_seq) {
-		if (mail_cache_unlock(cache) < 0)
-			return -1;
-		mail_cache_transaction_reset(ctx);
-		return 0;
+		/* already written cache records must be forgotten, but records
+		   in memory can still be written to the new cache file */
+		mail_cache_transaction_forget_flushed(ctx);
+		i_assert(ctx->cache_file_seq == cache->hdr->file_seq);
 	}
 	return 1;
 }
@@ -750,13 +752,9 @@ void mail_cache_add(struct mail_cache_transaction_ctx *ctx, uint32_t seq,
 	    (MAIL_CACHE_DECISION_NO | MAIL_CACHE_DECISION_FORCED))
 		return;
 
-	if (MAIL_CACHE_IS_UNUSABLE(ctx->cache) && !ctx->tried_compression) {
-		/* Cache file isn't created yet. Create it using compression
-		   before anything is added to transaction, so fields aren't
-		   lost when compression causes transaction to be reset.
-		   FIXME: get rid of this in later commits */
-		(void)mail_cache_transaction_compress(ctx);
-	}
+	/* If the cache file exists, make sure the caching decisions have been
+	   read. */
+	mail_cache_transaction_open_if_needed(ctx);
 
 	mail_cache_decision_add(ctx->view, seq, field_idx);