Btrfs: don't flush all delalloc inodes when we doesn't get s_umount lock

We needn't flush all delalloc inodes when we doesn't get s_umount lock,
or we would make the tasks wait for a long time.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

1 files changed, 19 insertions, 15 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f5e6233..fbaf1ac 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8437,7 +8437,8 @@ void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
  * some fairly slow code that needs optimization. This walks the list
  * of all the inodes with pending delalloc and forces them to disk.
  */
-static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
+static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
+				   int nr)
 {
 	struct btrfs_inode *binode;
 	struct inode *inode;
@@ -8471,12 +8472,14 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 			else
 				iput(inode);
 			ret = -ENOMEM;
-			goto out;
+			break;
 		}
 		list_add_tail(&work->list, &works);
 		btrfs_queue_work(root->fs_info->flush_workers,
 				 &work->work);
-
+		ret++;
+		if (nr != -1 && ret >= nr)
+			break;
 		cond_resched();
 		spin_lock(&root->delalloc_lock);
 	}
@@ -8486,12 +8489,6 @@ static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 		list_del_init(&work->list);
 		btrfs_wait_and_free_delalloc_work(work);
 	}
-	return 0;
-out:
-	list_for_each_entry_safe(work, next, &works, list) {
-		list_del_init(&work->list);
-		btrfs_wait_and_free_delalloc_work(work);
-	}
 
 	if (!list_empty_careful(&splice)) {
 		spin_lock(&root->delalloc_lock);
@@ -8508,7 +8505,9 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
 		return -EROFS;
 
-	ret = __start_delalloc_inodes(root, delay_iput);
+	ret = __start_delalloc_inodes(root, delay_iput, -1);
+	if (ret > 0)
+		ret = 0;
 	/*
 	 * the filemap_flush will queue IO into the worker threads, but
 	 * we have to make sure the IO is actually started and that
@@ -8525,7 +8524,8 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
 	return ret;
 }
 
-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
+			       int nr)
 {
 	struct btrfs_root *root;
 	struct list_head splice;
@@ -8538,7 +8538,7 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
 
 	spin_lock(&fs_info->delalloc_root_lock);
 	list_splice_init(&fs_info->delalloc_roots, &splice);
-	while (!list_empty(&splice)) {
+	while (!list_empty(&splice) && nr) {
 		root = list_first_entry(&splice, struct btrfs_root,
 					delalloc_root);
 		root = btrfs_grab_fs_root(root);
@@ -8547,15 +8547,20 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
 			       &fs_info->delalloc_roots);
 		spin_unlock(&fs_info->delalloc_root_lock);
 
-		ret = __start_delalloc_inodes(root, delay_iput);
+		ret = __start_delalloc_inodes(root, delay_iput, nr);
 		btrfs_put_fs_root(root);
-		if (ret)
+		if (ret < 0)
 			goto out;
 
+		if (nr != -1) {
+			nr -= ret;
+			WARN_ON(nr < 0);
+		}
 		spin_lock(&fs_info->delalloc_root_lock);
 	}
 	spin_unlock(&fs_info->delalloc_root_lock);
 
+	ret = 0;
 	atomic_inc(&fs_info->async_submit_draining);
 	while (atomic_read(&fs_info->nr_async_submits) ||
 	      atomic_read(&fs_info->async_delalloc_pages)) {
@@ -8564,7 +8569,6 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
 		    atomic_read(&fs_info->async_delalloc_pages) == 0));
 	}
 	atomic_dec(&fs_info->async_submit_draining);
-	return 0;
 out:
 	if (!list_empty_careful(&splice)) {
 		spin_lock(&fs_info->delalloc_root_lock);