cifs: reduce roundtrips on create/qinfo requests

[linux-2.6-microblaze.git] / fs / cifs / smb2ops.c

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index d33b00a..dc160de 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -796,7 +796,9 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
        int rc;
        __le16 *utf16_path;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+       int err_buftype = CIFS_NO_BUFFER;
        struct cifs_open_parms oparms;
+       struct kvec err_iov = {};
        struct cifs_fid fid;
        struct cached_fid *cfid;
 
@@ -820,14 +822,32 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
        oparms.fid = &fid;
        oparms.reconnect = false;
 
-       rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL,
-                      NULL);
+       rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
+                      &err_iov, &err_buftype);
        if (rc) {
-               kfree(utf16_path);
-               return rc;
+               struct smb2_hdr *hdr = err_iov.iov_base;
+
+               if (unlikely(!hdr || err_buftype == CIFS_NO_BUFFER))
+                       goto out;
+               /*
+                * Handle weird Windows SMB server behaviour. It responds with
+                * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
+                * for "\<server>\<dfsname>\<linkpath>" DFS reference,
+                * where <dfsname> contains non-ASCII unicode symbols.
+                */
+               if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) &&
+                   hdr->Status == STATUS_OBJECT_NAME_INVALID)
+                       rc = -EREMOTE;
+               if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb &&
+                   (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS))
+                       rc = -EOPNOTSUPP;
+               goto out;
        }
 
        rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+
+out:
+       free_rsp_buf(err_buftype, err_iov.iov_base);
        kfree(utf16_path);
        return rc;
 }