2 files changed, 11 insertions, 7 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ca76b5ed6c9e..0a31197590d7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2462,6 +2462,16 @@ static int ext4_nonda_switch(struct super_block *sb)
         free_blocks  = EXT4_C2B(sbi,
                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
         dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
+        /*
+         * Start pushing delalloc when 1/2 of free blocks are dirty.
+         */
+        if (dirty_blocks && (free_blocks < 2 * dirty_blocks) &&
+            !writeback_in_progress(sb->s_bdi) &&
+            down_read_trylock(&sb->s_umount)) {
+                writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
+                up_read(&sb->s_umount);
+        }
+
         if (2 * free_blocks < 3 * dirty_blocks ||
                 free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
                 /*
@@ -2470,13 +2480,6 @@ static int ext4_nonda_switch(struct super_block *sb)
                  */
                 return 1;
         }
-        /*
-         * Even if we don't switch but are nearing capacity,
-         * start pushing delalloc when 1/2 of free blocks are dirty.
-         */
-        if (free_blocks < 2 * dirty_blocks)
-                writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);
-
         return 0;
 }
 
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index be3efc4f64f4..5602d73d4ec7 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -63,6 +63,7 @@ int writeback_in_progress(struct backing_dev_info *bdi)
 {
         return test_bit(BDI_writeback_running, &bdi->state);
 }
+EXPORT_SYMBOL(writeback_in_progress);
 
 static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
 {