smb: client: use actual path when queryfs

Due to server permission control, the client does not have access to
the shared root directory, but can access subdirectories normally, so
users usually mount the shared subdirectories directly. In this case,
queryfs should use the actual path instead of the root directory to
avoid the call returning an error (EACCES).

Signed-off-by: wangrong <[e-mail]>
Reviewed-by: Paulo Alcantara (Red Hat) <[e-mail]>
Cc: [e-mail]
Signed-off-by: Steve French <[e-mail]>

fs/smb/client/cifsfs.c

···
 	struct TCP_Server_Info *server = tcon->ses->server;
 	unsigned int xid;
 	int rc = 0;
+	const char *full_path;
+	void *page;
 
 	xid = get_xid();
+	page = alloc_dentry_path();
+
+	full_path = build_path_from_dentry(dentry, page);
+	if (IS_ERR(full_path)) {
+		rc = PTR_ERR(full_path);
+		goto statfs_out;
+	}
 
 	if (le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength) > 0)
 		buf->f_namelen =
···
 	buf->f_ffree = 0;	/* unlimited */
 
 	if (server->ops->queryfs)
-		rc = server->ops->queryfs(xid, tcon, cifs_sb, buf);
+		rc = server->ops->queryfs(xid, tcon, full_path, cifs_sb, buf);
 
+statfs_out:
+	free_dentry_path(page);
 	free_xid(xid);
 	return rc;
 }

fs/smb/client/cifsglob.h

···
 			__u16 net_fid, struct cifsInodeInfo *cifs_inode);
 	/* query remote filesystem */
 	int (*queryfs)(const unsigned int, struct cifs_tcon *,
-		       struct cifs_sb_info *, struct kstatfs *);
+		       const char *, struct cifs_sb_info *, struct kstatfs *);
 	/* send mandatory brlock to the server */
 	int (*mand_lock)(const unsigned int, struct cifsFileInfo *, __u64,
 			 __u64, __u32, int, int, bool);

fs/smb/client/smb1ops.c

···
 
 static int
 cifs_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
-	     struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
+	     const char *path, struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
 {
 	int rc = -EOPNOTSUPP;
 

fs/smb/client/smb2ops.c

···
 
 static int
 smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
-	     struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
+	     const char *path, struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
 {
 	struct smb2_query_info_rsp *rsp;
 	struct smb2_fs_full_size_info *info = NULL;
···
 	int rc;
 
 
-	rc = smb2_query_info_compound(xid, tcon, "",
+	rc = smb2_query_info_compound(xid, tcon, path,
 				      FILE_READ_ATTRIBUTES,
 				      FS_FULL_SIZE_INFORMATION,
 				      SMB2_O_INFO_FILESYSTEM,
···
 
 static int
 smb311_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
-	       struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
+	       const char *path, struct cifs_sb_info *cifs_sb, struct kstatfs *buf)
 {
 	int rc;
-	__le16 srch_path = 0; /* Null - open root of share */
+	__le16 *utf16_path = NULL;
 	u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct cifs_open_parms oparms;
 	struct cifs_fid fid;
 
 	if (!tcon->posix_extensions)
-		return smb2_queryfs(xid, tcon, cifs_sb, buf);
+		return smb2_queryfs(xid, tcon, path, cifs_sb, buf);
 
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
-		.path = "",
+		.path = path,
 		.desired_access = FILE_READ_ATTRIBUTES,
 		.disposition = FILE_OPEN,
 		.create_options = cifs_create_options(cifs_sb, 0),
 		.fid = &fid,
 	};
 
-	rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL,
+	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
+	if (utf16_path == NULL)
+		return -ENOMEM;
+
+	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
 		       NULL, NULL);
+	kfree(utf16_path);
 	if (rc)
 		return rc;