[CIFS] Fix path based calls to consistently allow up to PATH_MAX (some were

incorrectly limited to just over 512)

Pointed out by Shaggy.

Signed-off-by: Steve French (sfrench@us.ibm.com)

fs/cifs/CHANGES

@@ -6,6 +6,8 @@ when mounting with the directio mount option. Fix oops after
 returning from mount when experimental ExtendedSecurity enabled and
 SpnegoNegotiated returning invalid error. Fix case to retry better when 
 peek returns from 1 to 3 bytes on socket which should have more data.
+Fixed path based calls (such as cifs lookup) to handle path names
+longer than 530 (now can handle PATH_MAX).
 
 Version 1.27
 ------------

fs/cifs/cifsfs.c

@@ -60,7 +60,7 @@ unsigned int sign_CIFS_PDUs = 1;
 struct task_struct * oplockThread = NULL;
 unsigned int CIFSMaxBufSize = CIFS_MAX_MSGSIZE;
 module_param(CIFSMaxBufSize, int, CIFS_MAX_MSGSIZE);
-MODULE_PARM_DESC(CIFSMaxBufSize,"Network buffer size (not including header). Default: 16384 Range: 4096 to 130048");
+MODULE_PARM_DESC(CIFSMaxBufSize,"Network buffer size (not including header). Default: 16384 Range: 8192 to 130048");
 unsigned int cifs_min_rcv = CIFS_MIN_RCV_POOL;
 module_param(cifs_min_rcv, int, CIFS_MIN_RCV_POOL);
 MODULE_PARM_DESC(cifs_min_rcv,"Network buffers in pool. Default: 4 Range: 1 to 64");
@@ -632,8 +632,10 @@ cifs_destroy_inodecache(void)
 static int
 cifs_init_request_bufs(void)
 {
-	if(CIFSMaxBufSize < 4096) {
-		CIFSMaxBufSize = 4096;
+	if(CIFSMaxBufSize < 8192) {
+	/* Buffer size can not be smaller than 2 * PATH_MAX since maximum
+	Unicode path name has to fit in any SMB/CIFS path based frames */
+		CIFSMaxBufSize = 8192;
 	} else if (CIFSMaxBufSize > 1024*127) {
 		CIFSMaxBufSize = 1024 * 127;
 	} else {