CIFS: Don't let read only caching for mandatory byte-range locked files

If we have mandatory byte-range locks on a file we can't cache reads
because pagereading may have conflicts with these locks on the server.
That's why we should allow level2 oplocks for files without mandatory
locks only.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index d79de7bc4435..c9c7aa7ed966 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -708,6 +708,7 @@ struct smb_version_values smb20_values = {
         .cap_unix = 0,
         .cap_nt_find = SMB2_NT_FIND,
         .cap_large_files = SMB2_LARGE_FILES,
+        .oplock_read = SMB2_OPLOCK_LEVEL_II,
 };
 
 struct smb_version_values smb21_values = {
@@ -725,6 +726,7 @@ struct smb_version_values smb21_values = {
         .cap_unix = 0,
         .cap_nt_find = SMB2_NT_FIND,
         .cap_large_files = SMB2_LARGE_FILES,
+        .oplock_read = SMB2_OPLOCK_LEVEL_II,
 };
 
 struct smb_version_values smb30_values = {