vfs: clean up generic_remap_file_range_prep return value

Since the remap prep function can update the length of the remap
request, we can change this function to return the usual return status
instead of the odd behavior it has now.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 6a42c04..46bbd31 100644 (file)
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -4852,7 +4852,7 @@ int ocfs2_reflink_remap_range(struct file *file_in,
 
        ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
                        &len, remap_flags);
-       if (ret <= 0)
+       if (ret < 0 || len == 0)
                goto out_unlock;
 
        /* Lock out changes to the allocation maps and remap. */

diff --git a/fs/read_write.c b/fs/read_write.c
index e4d295d..6b40a43 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1848,8 +1848,8 @@ out_error:
  * sense, and then flush all dirty data.  Caller must ensure that the
  * inodes have been locked against any other modifications.
  *
- * Returns: 0 for "nothing to clone", 1 for "something to clone", or
- * the usual negative error code.
+ * If there's an error, then the usual negative error code is returned.
+ * Otherwise returns 0 with *len set to the request length.
  */
 int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
                                  struct file *file_out, loff_t pos_out,
@@ -1945,7 +1945,7 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
                        return ret;
        }
 
-       return 1;
+       return 0;
 }
 EXPORT_SYMBOL(generic_remap_file_range_prep);
 

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 3dbe5fb..9b1ea42 100644 (file)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1329,7 +1329,7 @@ xfs_reflink_remap_prep(
 
        ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
                        len, remap_flags);
-       if (ret <= 0)
+       if (ret < 0 || *len == 0)
                goto out_unlock;
 
        /*
@@ -1409,7 +1409,7 @@ xfs_reflink_remap_range(
        /* Prepare and then clone file data. */
        ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
                        &len, remap_flags);
-       if (ret <= 0)
+       if (ret < 0 || len == 0)
                return ret;
 
        trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);