Btrfs: Set nodatasum on the inode when written by a nodatasum mount

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3f5525f0834c..5d537f26dc83 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -864,6 +864,14 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 
         /*
+         * if this is a nodatasum mount, force summing off for the inode
+         * all the time.  That way a later mount with summing on won't
+         * get confused
+         */
+        if (btrfs_test_opt(root, NODATASUM))
+                btrfs_set_flag(inode, NODATASUM);
+
+        /*
          * there are lots of better ways to do this, but this code
          * makes sure the first and last page in the file range are
          * up to date and ready for cow