[PATCH v2 3/5] compact: preserve backup database until compacted database is in place

diff --git a/bd/934a041d1ed492696104cccae9b9fc0368bc17 b/bd/934a041d1ed492696104cccae9b9fc0368bc17
new file mode 100644 (file)
index 0000000..c8a81ee
--- /dev/null
+++ b/bd/934a041d1ed492696104cccae9b9fc0368bc17
@@ -0,0 +1,132 @@
+Return-Path: <too@guru-group.fi>\r
+X-Original-To: notmuch@notmuchmail.org\r
+Delivered-To: notmuch@notmuchmail.org\r
+Received: from localhost (localhost [127.0.0.1])\r
+       by olra.theworths.org (Postfix) with ESMTP id 04F87431E82\r
+       for <notmuch@notmuchmail.org>; Wed, 13 Nov 2013 09:03:03 -0800 (PST)\r
+X-Virus-Scanned: Debian amavisd-new at olra.theworths.org\r
+X-Spam-Flag: NO\r
+X-Spam-Score: 0\r
+X-Spam-Level: \r
+X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none]\r
+       autolearn=disabled\r
+Received: from olra.theworths.org ([127.0.0.1])\r
+       by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024)\r
+       with ESMTP id cI-b-5us4uYx for <notmuch@notmuchmail.org>;\r
+       Wed, 13 Nov 2013 09:02:56 -0800 (PST)\r
+Received: from guru.guru-group.fi (guru.guru-group.fi [46.183.73.34])\r
+       by olra.theworths.org (Postfix) with ESMTP id 6D264431FD0\r
+       for <notmuch@notmuchmail.org>; Wed, 13 Nov 2013 09:02:56 -0800 (PST)\r
+Received: by guru.guru-group.fi (Postfix, from userid 501)\r
+       id 15DDD1000F3; Wed, 13 Nov 2013 19:02:52 +0200 (EET)\r
+From: Tomi Ollila <tomi.ollila@iki.fi>\r
+To: notmuch@notmuchmail.org\r
+Subject: [PATCH v2 3/5] compact: preserve backup database until compacted\r
+       database is in place\r
+Date: Wed, 13 Nov 2013 19:02:45 +0200\r
+Message-Id: <1384362167-12740-4-git-send-email-tomi.ollila@iki.fi>\r
+X-Mailer: git-send-email 1.8.0\r
+In-Reply-To: <1384362167-12740-1-git-send-email-tomi.ollila@iki.fi>\r
+References: <1384362167-12740-1-git-send-email-tomi.ollila@iki.fi>\r
+Cc: tomi.ollila@iki.fi\r
+X-BeenThere: notmuch@notmuchmail.org\r
+X-Mailman-Version: 2.1.13\r
+Precedence: list\r
+List-Id: "Use and development of the notmuch mail system."\r
+       <notmuch.notmuchmail.org>\r
+List-Unsubscribe: <http://notmuchmail.org/mailman/options/notmuch>,\r
+       <mailto:notmuch-request@notmuchmail.org?subject=unsubscribe>\r
+List-Archive: <http://notmuchmail.org/pipermail/notmuch>\r
+List-Post: <mailto:notmuch@notmuchmail.org>\r
+List-Help: <mailto:notmuch-request@notmuchmail.org?subject=help>\r
+List-Subscribe: <http://notmuchmail.org/mailman/listinfo/notmuch>,\r
+       <mailto:notmuch-request@notmuchmail.org?subject=subscribe>\r
+X-List-Received-Date: Wed, 13 Nov 2013 17:03:03 -0000\r
+\r
+It is less error prone and window of failure opportunity is smaller\r
+if the old (backup) database is always renamed (instead of sometimes\r
+rmtree'd) before new (compacted) database is put into its place.\r
+Finally rmtree() old database in case old database backup is not kept.\r
+---\r
+ lib/database.cc | 42 +++++++++++++++++++++++++-----------------\r
+ 1 file changed, 25 insertions(+), 17 deletions(-)\r
+\r
+diff --git a/lib/database.cc b/lib/database.cc\r
+index 3530cb6..ee09c5e 100644\r
+--- a/lib/database.cc\r
++++ b/lib/database.cc\r
+@@ -873,6 +873,7 @@ notmuch_database_compact (const char *path,\r
+     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;\r
+     notmuch_database_t *notmuch = NULL;\r
+     struct stat statbuf;\r
++    notmuch_bool_t keep_backup;\r
+ \r
+     local = talloc_new (NULL);\r
+     if (! local)\r
+@@ -898,17 +899,25 @@ notmuch_database_compact (const char *path,\r
+       goto DONE;\r
+     }\r
+ \r
+-    if (backup_path != NULL) {\r
+-      if (stat (backup_path, &statbuf) != -1) {\r
+-          fprintf (stderr, "Backup path already exists: %s\n", backup_path);\r
+-          ret = NOTMUCH_STATUS_FILE_ERROR;\r
+-          goto DONE;\r
+-      }\r
+-      if (errno != ENOENT) {\r
+-          fprintf (stderr, "Unknown error while stat()ing backup path: %s\n",\r
+-                   strerror (errno));\r
++    if (backup_path == NULL) {\r
++      if (! (backup_path = talloc_asprintf (local, "%s.old", xapian_path))) {\r
++          ret = NOTMUCH_STATUS_OUT_OF_MEMORY;\r
+           goto DONE;\r
+       }\r
++      keep_backup = FALSE;\r
++    }\r
++    else\r
++      keep_backup = TRUE;\r
++\r
++    if (stat (backup_path, &statbuf) != -1) {\r
++      fprintf (stderr, "Backup path already exists: %s\n", backup_path);\r
++      ret = NOTMUCH_STATUS_FILE_ERROR;\r
++      goto DONE;\r
++    }\r
++    if (errno != ENOENT) {\r
++      fprintf (stderr, "Unknown error while stat()ing backup path: %s\n",\r
++               strerror (errno));\r
++      goto DONE;\r
+     }\r
+ \r
+     try {\r
+@@ -924,14 +933,10 @@ notmuch_database_compact (const char *path,\r
+       goto DONE;\r
+     }\r
+ \r
+-    if (backup_path) {\r
+-      if (rename (xapian_path, backup_path)) {\r
+-          fprintf (stderr, "Error moving old database out of the way\n");\r
+-          ret = NOTMUCH_STATUS_FILE_ERROR;\r
+-          goto DONE;\r
+-      }\r
+-    } else {\r
+-      rmtree (xapian_path);\r
++    if (rename (xapian_path, backup_path)) {\r
++      fprintf (stderr, "Error moving old database out of the way\n");\r
++      ret = NOTMUCH_STATUS_FILE_ERROR;\r
++      goto DONE;\r
+     }\r
+ \r
+     if (rename (compact_xapian_path, xapian_path)) {\r
+@@ -940,6 +945,9 @@ notmuch_database_compact (const char *path,\r
+       goto DONE;\r
+     }\r
+ \r
++    if (! keep_backup)\r
++      rmtree (backup_path);\r
++\r
+   DONE:\r
+     if (notmuch)\r
+       notmuch_database_destroy (notmuch);\r
+-- \r
+1.8.3.1\r
+\r