cifs: change CIFSSMBUnixQuerySymLink to use new helpers

Change CIFSSMBUnixQuerySymLink to use the new unicode helper functions.
Also change the calling conventions so that the allocation of the target
name buffer is done in CIFSSMBUnixQuerySymLink rather than by the caller.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsproto.h

@@ -260,8 +260,7 @@ extern int CIFSUnixCreateSymLink(const int xid,
 			const struct nls_table *nls_codepage);
 extern int CIFSSMBUnixQuerySymLink(const int xid,
 			struct cifsTconInfo *tcon,
-			const unsigned char *searchName,
-			char *syminfo, const int buflen,
+			const unsigned char *searchName, char **syminfo,
 			const struct nls_table *nls_codepage);
 extern int CIFSSMBQueryReparseLinkInfo(const int xid,
 			struct cifsTconInfo *tcon,

fs/cifs/cifssmb.c

@@ -2382,8 +2382,7 @@ winCreateHardLinkRetry:
 
 int
 CIFSSMBUnixQuerySymLink(const int xid, struct cifsTconInfo *tcon,
-			const unsigned char *searchName,
-			char *symlinkinfo, const int buflen,
+			const unsigned char *searchName, char **symlinkinfo,
 			const struct nls_table *nls_codepage)
 {
 /* SMB_QUERY_FILE_UNIX_LINK */
@@ -2393,6 +2392,7 @@ CIFSSMBUnixQuerySymLink(const int xid, struct cifsTconInfo *tcon,
 	int bytes_returned;
 	int name_len;
 	__u16 params, byte_count;
+	char *data_start;
 
 	cFYI(1, ("In QPathSymLinkInfo (Unix) for path %s", searchName));
 
@@ -2447,30 +2447,22 @@ querySymLinkRetry:
 		/* decode response */
 
 		rc = validate_t2((struct smb_t2_rsp *)pSMBr);
-		if (rc || (pSMBr->ByteCount < 2))
 		/* BB also check enough total bytes returned */
-			rc = -EIO;	/* bad smb */
+		if (rc || (pSMBr->ByteCount < 2))
+			rc = -EIO;
 		else {
-			__u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset);
-			__u16 count = le16_to_cpu(pSMBr->t2.DataCount);
+			u16 count = le16_to_cpu(pSMBr->t2.DataCount);
+
+			data_start = ((char *) &pSMBr->hdr.Protocol) +
+					   le16_to_cpu(pSMBr->t2.DataOffset);
 
-			if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE) {
-				name_len = UniStrnlen((wchar_t *) ((char *)
-					&pSMBr->hdr.Protocol + data_offset),
-					min_t(const int, buflen, count) / 2);
 			/* BB FIXME investigate remapping reserved chars here */
-				cifs_strfromUCS_le(symlinkinfo,
-					(__le16 *) ((char *)&pSMBr->hdr.Protocol
-							+ data_offset),
-					name_len, nls_codepage);
-			} else {
-				strncpy(symlinkinfo,
-					(char *) &pSMBr->hdr.Protocol +
-						data_offset,
-					min_t(const int, buflen, count));
-			}
-			symlinkinfo[buflen] = 0;
-	/* just in case so calling code does not go off the end of buffer */
+			*symlinkinfo = cifs_strndup(data_start, count,
+						    pSMBr->hdr.Flags2 &
+							SMBFLG2_UNICODE,
+						    nls_codepage);
+			if (!symlinkinfo)
+				rc = -ENOMEM;
 		}
 	}
 	cifs_buf_release(pSMB);

fs/cifs/link.c

@@ -119,16 +119,11 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	full_path = build_path_from_dentry(direntry);
 
 	if (!full_path)
-		goto out_no_free;
+		goto out;
 
 	cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
-	target_path = kmalloc(PATH_MAX, GFP_KERNEL);
-	if (!target_path) {
-		target_path = ERR_PTR(-ENOMEM);
-		goto out;
-	}
 
 	/* We could change this to:
 		if (pTcon->unix_ext)
@@ -138,8 +133,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
 	if (pTcon->ses->capabilities & CAP_UNIX)
 		rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
-					     target_path,
-					     PATH_MAX-1,
+					     &target_path,
 					     cifs_sb->local_nls);
 	else {
 		/* BB add read reparse point symlink code here */
@@ -148,22 +142,16 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 		/* BB Add MAC style xsymlink check here if enabled */
 	}
 
-	if (rc == 0) {
-
-/* BB Add special case check for Samba DFS symlinks */
-
-		target_path[PATH_MAX-1] = 0;
-	} else {
+	if (rc != 0) {
 		kfree(target_path);
 		target_path = ERR_PTR(rc);
 	}
 
-out:
 	kfree(full_path);
-out_no_free:
+out:
 	FreeXid(xid);
 	nd_set_link(nd, target_path);
-	return NULL;	/* No cookie */
+	return NULL;
 }
 
 int