vfs: make remap_file_range functions take and return bytes completed
Change the remap_file_range functions to take a number of bytes to
operate upon and return the number of bytes they operated on. This is a
requirement for allowing fs implementations to return short clone/dedupe
results to the user, which will enable us to obey resource limits in a
graceful manner.
A subsequent patch will enable copy_file_range to signal to the
->clone_file_range implementation that it can handle a short length,
which will be returned in the function's return value. For now the
short return is not implemented anywhere so the behavior won't change --
either copy_file_range manages to clone the entire range or it tries an
alternative.
Neither clone ioctl can take advantage of this, alas.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index e8144d0..5ca71c6 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -975,8 +975,8 @@ const struct inode_operations cifs_symlink_inode_ops = {
.listxattr = cifs_listxattr,
};
-static int cifs_remap_file_range(struct file *src_file, loff_t off,
- struct file *dst_file, loff_t destoff, u64 len,
+static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
+ struct file *dst_file, loff_t destoff, loff_t len,
unsigned int remap_flags)
{
struct inode *src_inode = file_inode(src_file);
@@ -1029,7 +1029,7 @@ static int cifs_remap_file_range(struct file *src_file, loff_t off,
unlock_two_nondirectories(src_inode, target_inode);
out:
free_xid(xid);
- return rc;
+ return rc < 0 ? rc : len;
}
ssize_t cifs_file_copychunk_range(unsigned int xid,