Btrfs: make ordered extent be flushed by multi-task

Though the process of the ordered extents is a bit different with the delalloc inode
flush, but we can see it as a subset of the delalloc inode flush, so we also handle
them by flush workers.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

2 files changed, 37 insertions, 9 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index ab2a3c0c540f..eecc20f14cfa 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -211,6 +211,8 @@ static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
         init_waitqueue_head(&entry->wait);
         INIT_LIST_HEAD(&entry->list);
         INIT_LIST_HEAD(&entry->root_extent_list);
+        INIT_LIST_HEAD(&entry->work_list);
+        init_completion(&entry->completion);
 
         trace_btrfs_ordered_extent_add(inode, entry);
 
@@ -464,18 +466,28 @@ void btrfs_remove_ordered_extent(struct inode *inode,
         wake_up(&entry->wait);
 }
 
+static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
+{
+        struct btrfs_ordered_extent *ordered;
+
+        ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
+        btrfs_start_ordered_extent(ordered->inode, ordered, 1);
+        complete(&ordered->completion);
+}
+
 /*
  * wait for all the ordered extents in a root.  This is done when balancing
  * space between drives.
  */
 void btrfs_wait_ordered_extents(struct btrfs_root *root, int delay_iput)
 {
-        struct list_head splice;
+        struct list_head splice, works;
         struct list_head *cur;
-        struct btrfs_ordered_extent *ordered;
+        struct btrfs_ordered_extent *ordered, *next;
         struct inode *inode;
 
         INIT_LIST_HEAD(&splice);
+        INIT_LIST_HEAD(&works);
 
         spin_lock(&root->fs_info->ordered_extent_lock);
         list_splice_init(&root->fs_info->ordered_extents, &splice);
@@ -494,19 +506,32 @@ void btrfs_wait_ordered_extents(struct btrfs_root *root, int delay_iput)
                 spin_unlock(&root->fs_info->ordered_extent_lock);
 
                 if (inode) {
-                        btrfs_start_ordered_extent(inode, ordered, 1);
-                        btrfs_put_ordered_extent(ordered);
-                        if (delay_iput)
-                                btrfs_add_delayed_iput(inode);
-                        else
-                                iput(inode);
+                        ordered->flush_work.func = btrfs_run_ordered_extent_work;
+                        list_add_tail(&ordered->work_list, &works);
+                        btrfs_queue_worker(&root->fs_info->flush_workers,
+                                           &ordered->flush_work);
                 } else {
                         btrfs_put_ordered_extent(ordered);
                 }
 
+                cond_resched();
                 spin_lock(&root->fs_info->ordered_extent_lock);
         }
         spin_unlock(&root->fs_info->ordered_extent_lock);
+
+        list_for_each_entry_safe(ordered, next, &works, work_list) {
+                list_del_init(&ordered->work_list);
+                wait_for_completion(&ordered->completion);
+
+                inode = ordered->inode;
+                btrfs_put_ordered_extent(ordered);
+                if (delay_iput)
+                        btrfs_add_delayed_iput(inode);
+                else
+                        iput(inode);
+
+                cond_resched();
+        }
 }
 
 /*
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index e8dcec635112..efc7c2930c17 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -128,8 +128,11 @@ struct btrfs_ordered_extent {
         struct list_head root_extent_list;
 
         struct btrfs_work work;
-};
 
+        struct completion completion;
+        struct btrfs_work flush_work;
+        struct list_head work_list;
+};
 
 /*
  * calculates the total size you need to allocate for an ordered sum