From: Josef Bacik <josef@toxicpanda.com>
Date: Wed, 14 Jul 2021 14:47:23 -0400
Subject: btrfs: use the filemap_fdatawrite_wbc helper for delalloc shrinking
Git-commit: b3776305278e5937366f512d3e655ace13b8b027
Patch-mainline: v5.15-rc1
References: bsc#1202528

sync_inode() has some holes that can cause problems if we're under heavy
ENOSPC pressure.  If there's writeback running on a separate thread
sync_inode() will skip writing the inode altogether.  What we really
want is to make sure writeback has been started on all the pages to make
sure we can see the ordered extents and wait on them if appropriate.
Switch to this new helper which will allow us to accomplish this and
avoid ENOSPC'ing early.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 25eb214f56ac..c917e3117842 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9878,7 +9878,7 @@ static int start_delalloc_inodes(struct btrfs_root *root,
 			btrfs_queue_work(root->fs_info->flush_workers,
 					 &work->work);
 		} else {
-			ret = sync_inode(inode, wbc);
+			ret = filemap_fdatawrite_wbc(inode->i_mapping, wbc);
 			btrfs_add_delayed_iput(inode);
 			if (ret || wbc->nr_to_write <= 0)
 				goto out;