[evolution-data-server] [IMAPX] Do not hold queue_lock when calling imapx_server_ref_job()

[Milan Crha <mcrha src gnome org>]

commit ea4ef4f07fa18adfe981f4af1be9933904db65ed
Author: Milan Crha <mcrha redhat com>
Date:   Tue May 6 12:40:04 2014 +0200

    [IMAPX] Do not hold queue_lock when calling imapx_server_ref_job()
    
    Holding the queue_lock when calling imapx_server_ref_job() can cause
    deadlock when the store has opened more than one connection and each
    is searching for a duplicate job, both/all servers holding respective
    queue lock prevents in a search of active jobs in them, both waiting
    for a release of the queue_lock of the other server.

 camel/providers/imapx/camel-imapx-server.c |   25 ++++++++++---------------
 1 files changed, 10 insertions(+), 15 deletions(-)
---
diff --git a/camel/providers/imapx/camel-imapx-server.c b/camel/providers/imapx/camel-imapx-server.c
index 1887360..2b7b8db 100644
--- a/camel/providers/imapx/camel-imapx-server.c
+++ b/camel/providers/imapx/camel-imapx-server.c
@@ -1798,6 +1798,8 @@ imapx_match_active_job (CamelIMAPXServer *is,
        return match;
 }
 
+/* Do *not* call this when the queue_lock is held, it can cause
+   deadlock when searching between multiple servers */
 static CamelIMAPXJob *
 imapx_server_ref_job (CamelIMAPXServer *imapx_server,
                      CamelIMAPXMailbox *mailbox,
@@ -8132,8 +8134,6 @@ imapx_server_get_message (CamelIMAPXServer *is,
        GetMessageData *data;
        gboolean registered;
 
-       QUEUE_LOCK (is);
-
        job = imapx_server_ref_job (is, mailbox, IMAPX_JOB_GET_MESSAGE, message_uid);
 
        if (job != NULL) {
@@ -8142,8 +8142,6 @@ imapx_server_get_message (CamelIMAPXServer *is,
                if (pri > job->pri)
                        job->pri = pri;
 
-               QUEUE_UNLOCK (is);
-
                /* Wait for the job to finish. */
                camel_imapx_job_wait (job, NULL);
                camel_imapx_job_unref (job);
@@ -8158,10 +8156,10 @@ imapx_server_get_message (CamelIMAPXServer *is,
                        g_object_unref (cache_stream);
                        return stream;
                }
-
-               QUEUE_LOCK (is);
        }
 
+       QUEUE_LOCK (is);
+
        mi = camel_folder_summary_get (summary, message_uid);
        if (mi == NULL) {
                g_set_error (
@@ -8505,19 +8503,18 @@ camel_imapx_server_refresh_info (CamelIMAPXServer *is,
        g_return_val_if_fail (CAMEL_IS_IMAPX_SERVER (is), FALSE);
        g_return_val_if_fail (CAMEL_IS_IMAPX_MAILBOX (mailbox), FALSE);
 
-       QUEUE_LOCK (is);
-
        /* Don't run concurrent refreshes on the same mailbox.
         * If a refresh is already in progress, let it finish
         * and return no changes for this refresh request. */
        job = imapx_server_ref_job (is, mailbox, IMAPX_JOB_REFRESH_INFO, NULL);
 
        if (job != NULL) {
-               QUEUE_UNLOCK (is);
                camel_imapx_job_unref (job);
                return camel_folder_change_info_new ();
        }
 
+       QUEUE_LOCK (is);
+
        data = g_slice_new0 (RefreshInfoData);
        data->changes = camel_folder_change_info_new ();
 
@@ -8780,15 +8777,12 @@ imapx_server_sync_changes (CamelIMAPXServer *is,
 
        /* TODO above code should go into changes_start */
 
-       QUEUE_LOCK (is);
-
        job = imapx_server_ref_job (is, mailbox, IMAPX_JOB_SYNC_CHANGES, NULL);
 
        if (job != NULL) {
                if (pri > job->pri)
                        job->pri = pri;
 
-               QUEUE_UNLOCK (is);
                camel_imapx_job_unref (job);
 
                imapx_sync_free_user (on_user);
@@ -8798,6 +8792,8 @@ imapx_server_sync_changes (CamelIMAPXServer *is,
                return TRUE;
        }
 
+       QUEUE_LOCK (is);
+
        data = g_slice_new0 (SyncChangesData);
        data->folder = g_object_ref (folder);
        data->changed_uids = changed_uids;  /* takes ownership */
@@ -8865,16 +8861,15 @@ camel_imapx_server_expunge (CamelIMAPXServer *is,
        g_return_val_if_fail (CAMEL_IS_IMAPX_MAILBOX (mailbox), FALSE);
 
        /* Do we really care to wait for this one to finish? */
-       QUEUE_LOCK (is);
-
        job = imapx_server_ref_job (is, mailbox, IMAPX_JOB_EXPUNGE, NULL);
 
        if (job != NULL) {
-               QUEUE_UNLOCK (is);
                camel_imapx_job_unref (job);
                return TRUE;
        }
 
+       QUEUE_LOCK (is);
+
        job = camel_imapx_job_new (cancellable);
        job->type = IMAPX_JOB_EXPUNGE;
        job->start = imapx_job_expunge_start;