xfs: mark all internal workqueues as freezable

Workqueues must be explicitly set as freezable to ensure they are frozen
in the assocated part of the hibernation/suspend sequence. Freezing of
workqueues and kernel threads is important to ensure that modifications
are not made on-disk after the hibernation image has been created.
Otherwise, the in-memory state can become inconsistent with what is on
disk and eventually lead to filesystem corruption. We have reports of
free space btree corruptions that occur immediately after restore from
hibernate that suggest the xfs-eofblocks workqueue could be causing
such problems if it races with hibernation.

Mark all of the internal XFS workqueues as freezable to ensure nothing
changes on-disk once the freezer infrastructure freezes kernel threads
and creates the hibernation image.

Signed-off-by: Brian Foster <[e-mail]>
Reported-by: Carlos E. R. <[e-mail]>
Reviewed-by: Dave Chinner <[e-mail]>
Signed-off-by: Dave Chinner <[e-mail]>

fs/xfs/xfs_buf.c

···
 		goto out;
 
 	xfslogd_workqueue = alloc_workqueue("xfslogd",
-					WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
+				WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_FREEZABLE, 1);
 	if (!xfslogd_workqueue)
 		goto out_free_buf_zone;
 

fs/xfs/xfs_mru_cache.c

···
 int
 xfs_mru_cache_init(void)
 {
-	xfs_mru_reap_wq = alloc_workqueue("xfs_mru_cache", WQ_MEM_RECLAIM, 1);
+	xfs_mru_reap_wq = alloc_workqueue("xfs_mru_cache",
+				WQ_MEM_RECLAIM|WQ_FREEZABLE, 1);
 	if (!xfs_mru_reap_wq)
 		return -ENOMEM;
 	return 0;

fs/xfs/xfs_super.c

···
 	struct xfs_mount	*mp)
 {
 	mp->m_data_workqueue = alloc_workqueue("xfs-data/%s",
-			WQ_MEM_RECLAIM, 0, mp->m_fsname);
+			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_data_workqueue)
 		goto out;
 
 	mp->m_unwritten_workqueue = alloc_workqueue("xfs-conv/%s",
-			WQ_MEM_RECLAIM, 0, mp->m_fsname);
+			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_unwritten_workqueue)
 		goto out_destroy_data_iodone_queue;
 
 	mp->m_cil_workqueue = alloc_workqueue("xfs-cil/%s",
-			WQ_MEM_RECLAIM, 0, mp->m_fsname);
+			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_cil_workqueue)
 		goto out_destroy_unwritten;
 
 	mp->m_reclaim_workqueue = alloc_workqueue("xfs-reclaim/%s",
-			0, 0, mp->m_fsname);
+			WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_reclaim_workqueue)
 		goto out_destroy_cil;
 
 	mp->m_log_workqueue = alloc_workqueue("xfs-log/%s",
-			0, 0, mp->m_fsname);
+			WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_log_workqueue)
 		goto out_destroy_reclaim;
 
 	mp->m_eofblocks_workqueue = alloc_workqueue("xfs-eofblocks/%s",
-			0, 0, mp->m_fsname);
+			WQ_FREEZABLE, 0, mp->m_fsname);
 	if (!mp->m_eofblocks_workqueue)
 		goto out_destroy_log;
 
···
 	 * AGs in all the filesystems mounted. Hence use the default large
 	 * max_active value for this workqueue.
 	 */
-	xfs_alloc_wq = alloc_workqueue("xfsalloc", WQ_MEM_RECLAIM, 0);
+	xfs_alloc_wq = alloc_workqueue("xfsalloc",
+			WQ_MEM_RECLAIM|WQ_FREEZABLE, 0);
 	if (!xfs_alloc_wq)
 		return -ENOMEM;