dovecot-2.1: lib-storage: Fixed \Recent flag race conditions.

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.1/rev/cd413ab7aeb3
changeset: 14922:cd413ab7aeb3
user:      Timo Sirainen <tss at iki.fi>
date:      Sun Feb 24 15:50:26 2013 +0200
description:
lib-storage: Fixed \Recent flag race conditions.
The \Recent flags should only be set while locked within
mail_index_sync_begin()..commit(). The following view syncing syncs only up
to how far the index was synced, so it won't see any new messages that
haven't yet been assigned a \Recent flag.

diffstat:

 src/lib-storage/index/index-status.c |  13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diffs (23 lines):

diff -r e33fe1a7bb89 -r cd413ab7aeb3 src/lib-storage/index/index-status.c
--- a/src/lib-storage/index/index-status.c	Fri Feb 22 15:49:35 2013 +0200
+++ b/src/lib-storage/index/index-status.c	Sun Feb 24 15:50:26 2013 +0200
@@ -48,9 +48,16 @@
 	hdr = mail_index_get_header(box->view);
 	status_r->messages = hdr->messages_count;
 	if ((items & STATUS_RECENT) != 0) {
-		/* make sure recent count is set, in case syncing hasn't
-		   been done yet */
-		index_sync_update_recent_count(box);
+		if ((box->flags & MAILBOX_FLAG_DROP_RECENT) != 0) {
+			/* recent flags are set and dropped by the previous
+			   sync while index was locked. if we updated the
+			   recent flags here we'd have a race condition. */
+			i_assert(box->synced);
+		} else {
+			/* make sure recent count is set, in case we haven't
+			   synced yet */
+			index_sync_update_recent_count(box);
+		}
 		status_r->recent = index_mailbox_get_recent_count(box);
 		i_assert(status_r->recent <= status_r->messages);
 	}