cifs: fix regression with O_EXCL creates and optimize away lookup

cifs: fix regression with O_EXCL creates and optimize away lookup

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Shirish Pargaonkar <shirishp@gmail.com>
CC: Stable Kernel <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index a40054faed7f68d27f9a3cfbbed09ddf6e0b72b7..ff55fc6932cb805a25d58608a8cd8241e127d60c 100644 (file)
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -643,6 +643,15 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                        }
        }
 
+       /*
+        * O_EXCL: optimize away the lookup, but don't hash the dentry. Let
+        * the VFS handle the create.
+        */
+       if (nd->flags & LOOKUP_EXCL) {
+               d_instantiate(direntry, NULL);
+               return 0;
+       }
+
        /* can not grab the rename sem here since it would
        deadlock in the cases (beginning of sys_rename itself)
        in which we already have the sb rename sem */