[PATCH 4.20 352/352] nfsd: Fix error return values for nfsd4_clone_file_range()

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Trond Myklebust <trondmy@xxxxxxxxx>

commit e3fdc89ca47ef34dfb6fd5101fec084c3dba5486 upstream.

If the parameter 'count' is non-zero, nfsd4_clone_file_range() will
currently clobber all errors returned by vfs_clone_file_range() and
replace them with EINVAL.

Fixes: 42ec3d4c0218 ("vfs: make remap_file_range functions take and...")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.20+
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfsd/vfs.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -544,9 +544,11 @@ __be32 nfsd4_clone_file_range(struct fil
 	loff_t cloned;
 
 	cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
+	if (cloned < 0)
+		return nfserrno(cloned);
 	if (count && cloned != count)
-		cloned = -EINVAL;
-	return nfserrno(cloned < 0 ? cloned : 0);
+		return nfserrno(-EINVAL);
+	return 0;
 }
 
 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,