From: Timo Sirainen <tss@iki.fi>
Date: Mon, 7 Feb 2011 22:08:38 +0000 (+0200)
Subject: lib-index: Avoid writing tail offset unnecessarily to transaction log file.
X-Git-Tag: 2.1.alpha1~365
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8f430e257605b2fd2b54cdf4c2a20ef8b53cf0ba;p=thirdparty%2Fdovecot%2Fcore.git

lib-index: Avoid writing tail offset unnecessarily to transaction log file.
This could have happened with MAIL_INDEX_TRANSACTION_FLAG_AVOID_FLAG_UPDATES
when all flag updates were cancelled and no other changes were done.
---

diff --git a/src/lib-index/mail-transaction-log-append.c b/src/lib-index/mail-transaction-log-append.c
index d850c51b6f..83176b4b38 100644
--- a/src/lib-index/mail-transaction-log-append.c
+++ b/src/lib-index/mail-transaction-log-append.c
@@ -149,6 +149,13 @@ log_append_sync_offset_if_needed(struct mail_transaction_log_append_ctx *ctx)
 	unsigned char update_data[sizeof(*u) + sizeof(offset)];
 
 	if (file->max_tail_offset == file->sync_offset) {
+		if (ctx->output->used == 0 &&
+		    file->saved_tail_offset == file->max_tail_offset) {
+			/* nothing to write here after all (e.g. all unchanged
+			   flag updates were dropped by export) */
+			return;
+		}
+
 		/* FIXME: when we remove exclusive log locking, we
 		   can't rely on this. then write non-changed offset + check
 		   real offset + rewrite the new offset if other transactions