1 files changed, 8 insertions, 0 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 71c2dc1ea15a..7f4654a15207 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1472,6 +1472,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
         ssize_t num_written = 0;
         ssize_t err = 0;
         size_t count, ocount;
+        bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
 
         sb_start_write(inode->i_sb);
 
@@ -1529,6 +1530,9 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                 }
         }
 
+        if (sync)
+                atomic_inc(&BTRFS_I(inode)->sync_writers);
+
         if (unlikely(file->f_flags & O_DIRECT)) {
                 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
                                                    pos, ppos, count, ocount);
@@ -1563,6 +1567,8 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                         num_written = err;
         }
 out:
+        if (sync)
+                atomic_dec(&BTRFS_I(inode)->sync_writers);
         sb_end_write(inode->i_sb);
         current->backing_dev_info = NULL;
         return num_written ? num_written : err;
@@ -1613,7 +1619,9 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
          * out of the ->i_mutex. If so, we can flush the dirty pages by
          * multi-task, and make the performance up.
          */
+        atomic_inc(&BTRFS_I(inode)->sync_writers);
         ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+        atomic_dec(&BTRFS_I(inode)->sync_writers);
         if (ret)
                 return ret;