linux-kernel - [PATCH 2/2] fs/9p: detecting invalid options as much as possible

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Date:   Mon, 16 Apr 2018 15:48:29 +0800
From:   Chengguang Xu <cgxu519@....com>
To:     ericvh@...il.com, rminnich@...dia.gov, lucho@...kov.net
Cc:     v9fs-developer@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        Chengguang Xu <cgxu519@....com>
Subject: [PATCH 2/2] fs/9p: detecting invalid options as much as possible

Currently when detecting invalid options in option parsing,
some options(e.g. debug) just set errno and allow to continusly
validate other options so that it can detect invalid options
as much as possible and give proper error messages together.

This patch apply this policy to all options and the case of memory
allocation error in option parsing.

Signed-off-by: Chengguang Xu <cgxu519@....com>
---
 fs/9p/v9fs.c | 49 ++++++++++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index e622f0f..29ba937 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -192,10 +192,9 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 		return 0;
 
 	tmp_options = kstrdup(opts, GFP_KERNEL);
-	if (!tmp_options) {
-		ret = -ENOMEM;
-		goto fail_option_alloc;
-	}
+	if (!tmp_options)
+		return -ENOMEM;
+
 	options = tmp_options;
 
 	while ((p = strsep(&options, ",")) != NULL) {
@@ -263,18 +262,16 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 		case Opt_uname:
 			kfree(v9ses->uname);
 			v9ses->uname = match_strdup(&args[0]);
-			if (!v9ses->uname) {
-				ret = -ENOMEM;
-				goto free_and_return;
-			}
+			if (!v9ses->uname)
+				if (!ret)
+					ret = -ENOMEM;
 			break;
 		case Opt_remotename:
 			kfree(v9ses->aname);
 			v9ses->aname = match_strdup(&args[0]);
-			if (!v9ses->aname) {
-				ret = -ENOMEM;
-				goto free_and_return;
-			}
+			if (!v9ses->aname)
+				if (!ret)
+					ret = -ENOMEM;
 			break;
 		case Opt_nodevmap:
 			v9ses->nodev = 1;
@@ -292,24 +289,24 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 #ifdef CONFIG_9P_FSCACHE
 			kfree(v9ses->cachetag);
 			v9ses->cachetag = match_strdup(&args[0]);
-			if (!v9ses->cachetag) {
-				ret = -ENOMEM;
-				goto free_and_return;
-			}
+			if (!v9ses->cachetag)
+				if (!ret)
+					ret = -ENOMEM;
 #endif
 			break;
 		case Opt_cache:
 			s = match_strdup(&args[0]);
 			if (!s) {
-				ret = -ENOMEM;
+				if (!ret)
+					ret = -ENOMEM;
 				p9_debug(P9_DEBUG_ERROR,
 					 "problem allocating copy of cache arg\n");
-				goto free_and_return;
+				continue;
 			}
 			ret = get_cache_mode(s);
 			if (ret == -EINVAL) {
 				kfree(s);
-				goto free_and_return;
+				continue;
 			}
 
 			v9ses->cache = ret;
@@ -319,10 +316,11 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 		case Opt_access:
 			s = match_strdup(&args[0]);
 			if (!s) {
-				ret = -ENOMEM;
+				if (!ret)
+					ret = -ENOMEM;
 				p9_debug(P9_DEBUG_ERROR,
 					 "problem allocating copy of access arg\n");
-				goto free_and_return;
+				continue;
 			}
 
 			v9ses->flags &= ~V9FS_ACCESS_MASK;
@@ -341,14 +339,14 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 					pr_info("Unknown access argument %s\n",
 						s);
 					kfree(s);
-					goto free_and_return;
+					continue;
 				}
 				v9ses->uid = make_kuid(current_user_ns(), uid);
 				if (!uid_valid(v9ses->uid)) {
 					ret = -EINVAL;
 					pr_info("Uknown uid %s\n", s);
 					kfree(s);
-					goto free_and_return;
+					continue;
 				}
 			}
 
@@ -365,13 +363,14 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 			break;
 
 		default:
+			p9_debug(P9_DEBUG_ERROR,
+				"unrecognized mount option \"%s\" or missing value\n",
+					p);
 			continue;
 		}
 	}
 
-free_and_return:
 	kfree(tmp_options);
-fail_option_alloc:
 	return ret;
 }
 
-- 
1.8.3.1