ext3: Fix memory leak when quota options are specified multiple times

When usrjquota or grpjquota mount options are specified several times,
we leak memory storing the names. Free the memory correctly.
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext3/super.c

@@ -916,21 +916,24 @@ static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
 			"Not enough memory for storing quotafile name");
 		return 0;
 	}
-	if (sbi->s_qf_names[qtype] &&
-		strcmp(sbi->s_qf_names[qtype], qname)) {
-		ext3_msg(sb, KERN_ERR,
-			"%s quota file already specified", QTYPE2NAME(qtype));
+	if (sbi->s_qf_names[qtype]) {
+		int same = !strcmp(sbi->s_qf_names[qtype], qname);
+
 		kfree(qname);
-		return 0;
+		if (!same) {
+			ext3_msg(sb, KERN_ERR,
+				 "%s quota file already specified",
+				 QTYPE2NAME(qtype));
+		}
+		return same;
 	}
-	sbi->s_qf_names[qtype] = qname;
-	if (strchr(sbi->s_qf_names[qtype], '/')) {
+	if (strchr(qname, '/')) {
 		ext3_msg(sb, KERN_ERR,
 			"quotafile must be on filesystem root");
-		kfree(sbi->s_qf_names[qtype]);
-		sbi->s_qf_names[qtype] = NULL;
+		kfree(qname);
 		return 0;
 	}
+	sbi->s_qf_names[qtype] = qname;
 	set_opt(sbi->s_mount_opt, QUOTA);
 	return 1;
 }
@@ -945,11 +948,10 @@ static int clear_qf_name(struct super_block *sb, int qtype) {
 			" when quota turned on");
 		return 0;
 	}
-	/*
-	 * The space will be released later when all options are confirmed
-	 * to be correct
-	 */
-	sbi->s_qf_names[qtype] = NULL;
+	if (sbi->s_qf_names[qtype]) {
+		kfree(sbi->s_qf_names[qtype]);
+		sbi->s_qf_names[qtype] = NULL;
+	}
 	return 1;
 }
 #endif
@@ -2605,7 +2607,18 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
 #ifdef CONFIG_QUOTA
 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
 	for (i = 0; i < MAXQUOTAS; i++)
-		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
+		if (sbi->s_qf_names[i]) {
+			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
+							 GFP_KERNEL);
+			if (!old_opts.s_qf_names[i]) {
+				int j;
+
+				for (j = 0; j < i; j++)
+					kfree(old_opts.s_qf_names[j]);
+				return -ENOMEM;
+			}
+		} else
+			old_opts.s_qf_names[i] = NULL;
 #endif
 
 	/*
@@ -2698,9 +2711,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
 #ifdef CONFIG_QUOTA
 	/* Release old quota file names */
 	for (i = 0; i < MAXQUOTAS; i++)
-		if (old_opts.s_qf_names[i] &&
-		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
-			kfree(old_opts.s_qf_names[i]);
+		kfree(old_opts.s_qf_names[i]);
 #endif
 	if (enable_quota)
 		dquot_resume(sb, -1);
@@ -2714,9 +2725,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
 #ifdef CONFIG_QUOTA
 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
 	for (i = 0; i < MAXQUOTAS; i++) {
-		if (sbi->s_qf_names[i] &&
-		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
-			kfree(sbi->s_qf_names[i]);
+		kfree(sbi->s_qf_names[i]);
 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
 	}
 #endif