vfs: fix vfs_clone_file_range() for overlayfs files

With overlayfs, it is wrong to compare file_inode(inode)->i_sb
of regular files with those of non-regular files, because the
former reference the real (upper/lower) sb and the latter reference
the overlayfs sb.

Move the test for same super block after the sanity tests for
clone range of directory and non-regular file.

This change fixes xfstest generic/157, which returned EXDEV instead
of EISDIR/EINVAL in the following test cases over overlayfs:

  echo "Try to reflink a dir"
  _reflink_range $testdir1/dir1 0 $testdir1/file2 0 $blksz

  echo "Try to reflink a device"
  _reflink_range $testdir1/dev1 0 $testdir1/file2 0 $blksz

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/read_write.c b/fs/read_write.c
index c4e206b..53bccd1 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1655,6 +1655,11 @@ int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
        struct inode *inode_out = file_inode(file_out);
        int ret;
 
+       if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+               return -EISDIR;
+       if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+               return -EINVAL;
+
        /*
         * FICLONE/FICLONERANGE ioctls enforce that src and dest files are on
         * the same mount. Practically, they only need to be on the same file
@@ -1663,11 +1668,6 @@ int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
        if (inode_in->i_sb != inode_out->i_sb)
                return -EXDEV;
 
-       if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
-               return -EISDIR;
-       if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
-               return -EINVAL;
-
        if (!(file_in->f_mode & FMODE_READ) ||
            !(file_out->f_mode & FMODE_WRITE) ||
            (file_out->f_flags & O_APPEND))