cifs: fix creating sockets when using sfu mount options

When running fstest generic/423 with sfu mount option, it
was being skipped due to inability to create sockets:

  generic/423  [not run] cifs does not support mknod/mkfifo

which can also be easily reproduced with their af_unix tool:

  ./src/af_unix /mnt1/socket-two bind: Operation not permitted

Fix sfu mount option to allow creating and reporting sockets.

Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/cifspdu.h

@@ -2574,7 +2574,7 @@ typedef struct {
 
 
 struct win_dev {
-	unsigned char type[8]; /* IntxCHR or IntxBLK or LnxFIFO*/
+	unsigned char type[8]; /* IntxCHR or IntxBLK or LnxFIFO or LnxSOCK */
 	__le64 major;
 	__le64 minor;
 } __attribute__((packed));

fs/smb/client/inode.c

@@ -606,6 +606,10 @@ cifs_sfu_type(struct cifs_fattr *fattr, const char *path,
 				mnr = le64_to_cpu(*(__le64 *)(pbuf+16));
 				fattr->cf_rdev = MKDEV(mjr, mnr);
 			}
+		} else if (memcmp("LnxSOCK", pbuf, 8) == 0) {
+			cifs_dbg(FYI, "Socket\n");
+			fattr->cf_mode |= S_IFSOCK;
+			fattr->cf_dtype = DT_SOCK;
 		} else if (memcmp("IntxLNK", pbuf, 7) == 0) {
 			cifs_dbg(FYI, "Symlink\n");
 			fattr->cf_mode |= S_IFLNK;

fs/smb/client/smb2ops.c

@@ -4997,6 +4997,9 @@ static int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
 		pdev.major = cpu_to_le64(MAJOR(dev));
 		pdev.minor = cpu_to_le64(MINOR(dev));
 		break;
+	case S_IFSOCK:
+		strscpy(pdev.type, "LnxSOCK");
+		break;
 	case S_IFIFO:
 		strscpy(pdev.type, "LnxFIFO");
 		break;