Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Two fixes in this pull request:

   - The writeback regression fix from Tejun, which has been weeks in
     the making.  This fixes a case where we would sometimes not issue
     writeback when we should have.

   - An older fix for a memory corruption issue in mtip32xx.  It was
     deferred since we wanted a better fix for this (driver should not
     have to handle that case), but given the timing, it's better to put
     the simple fix in for 4.2 release"

* 'for-linus' of git://git.kernel.dk/linux-block:
  mtip32x: fix regression introduced by blk-mq per-hctx flush
  writeback: sync_inodes_sb() must write out I_DIRTY_TIME inodes and always call wait_sb_inodes()

Author: torvalds

drivers/block/mtip32xx/mtip32xx.c

@@ -3756,6 +3756,14 @@ static int mtip_init_cmd(void *data, struct request *rq, unsigned int hctx_idx,
 	struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq);
 	u32 host_cap_64 = readl(dd->mmio + HOST_CAP) & HOST_CAP_64;
 
+	/*
+	 * For flush requests, request_idx starts at the end of the
+	 * tag space.  Since we don't support FLUSH/FUA, simply return
+	 * 0 as there's nothing to be done.
+	 */
+	if (request_idx >= MTIP_MAX_COMMAND_SLOTS)
+		return 0;
+
 	cmd->command = dmam_alloc_coherent(&dd->pdev->dev, CMD_DMA_ALLOC_SZ,
 			&cmd->command_dma, GFP_KERNEL);
 	if (!cmd->command)

fs/fs-writeback.c

@@ -844,14 +844,15 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 	struct wb_iter iter;
 
 	might_sleep();
-
-	if (!bdi_has_dirty_io(bdi))
-		return;
 restart:
 	rcu_read_lock();
 	bdi_for_each_wb(wb, bdi, &iter, next_blkcg_id) {
-		if (!wb_has_dirty_io(wb) ||
-		    (skip_if_busy && writeback_in_progress(wb)))
+		/* SYNC_ALL writes out I_DIRTY_TIME too */
+		if (!wb_has_dirty_io(wb) &&
+		    (base_work->sync_mode == WB_SYNC_NONE ||
+		     list_empty(&wb->b_dirty_time)))
+			continue;
+		if (skip_if_busy && writeback_in_progress(wb))
 			continue;
 
 		base_work->nr_pages = wb_split_bdi_pages(wb, nr_pages);
@@ -899,8 +900,7 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 {
 	might_sleep();
 
-	if (bdi_has_dirty_io(bdi) &&
-	    (!skip_if_busy || !writeback_in_progress(&bdi->wb))) {
+	if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) {
 		base_work->auto_free = 0;
 		base_work->single_wait = 0;
 		base_work->single_done = 0;
@@ -2275,8 +2275,12 @@ void sync_inodes_sb(struct super_block *sb)
 	};
 	struct backing_dev_info *bdi = sb->s_bdi;
 
-	/* Nothing to do? */
-	if (!bdi_has_dirty_io(bdi) || bdi == &noop_backing_dev_info)
+	/*
+	 * Can't skip on !bdi_has_dirty() because we should wait for !dirty
+	 * inodes under writeback and I_DIRTY_TIME inodes ignored by
+	 * bdi_has_dirty() need to be written out too.
+	 */
+	if (bdi == &noop_backing_dev_info)
 		return;
 	WARN_ON(!rwsem_is_locked(&sb->s_umount));