ufs: reject multiple conflicting -o ufstype=... on mount

Have ufs_parse_options() refuse to change an already set flavour,
and move the "can't change the flavour" logics on remount there,
while we are at it - the only difference is that flavour is
already set.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 6a3a11c7e8cae8f72f0fdbf253fda2ebefae0469..33704b8d769dfe8ebfbabd0dd1037be810285a5c 100644 (file)
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -380,7 +380,7 @@ static const match_table_t tokens = {
        {Opt_err, NULL}
 };
 
-static int ufs_parse_options(char *options, unsigned *flavour, unsigned *on_err)
+static int ufs_parse_options(char *options, unsigned *flavour, unsigned *on_err, bool remount)
 {
        char * p;
        
@@ -392,6 +392,7 @@ static int ufs_parse_options(char *options, unsigned *flavour, unsigned *on_err)
        while ((p = strsep(&options, ",")) != NULL) {
                substring_t args[MAX_OPT_ARGS];
                int token;
+               unsigned int old = *flavour;
                if (!*p)
                        continue;
 
@@ -444,6 +445,15 @@ static int ufs_parse_options(char *options, unsigned *flavour, unsigned *on_err)
                        pr_err("Invalid option: \"%s\" or missing value\n", p);
                        return 0;
                }
+               if (*flavour == old)
+                       continue;
+               if (!old)
+                       continue;
+               if (remount)
+                       pr_err("ufstype can't be changed during remount\n");
+               else
+                       pr_err("conflicting ufstype options\n");
+               return 0;
        }
        return 1;
 }
@@ -795,7 +805,7 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
         */
        sbi->s_flavour = 0;
        sbi->s_on_err = UFS_MOUNT_ONERROR_LOCK;
-       if (!ufs_parse_options(data, &sbi->s_flavour, &sbi->s_on_err)) {
+       if (!ufs_parse_options(data, &sbi->s_flavour, &sbi->s_on_err, false)) {
                pr_err("wrong mount options\n");
                goto failed;
        }
@@ -1295,16 +1305,9 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
         * Allow the "check" option to be passed as a remount option.
         * It is not possible to change ufstype option during remount
         */
-       ufstype = 0;
+       ufstype = UFS_SB(sb)->s_flavour;
        on_err = UFS_MOUNT_ONERROR_LOCK;
-       if (!ufs_parse_options(data, &ufstype, &on_err)) {
-               mutex_unlock(&UFS_SB(sb)->s_lock);
-               return -EINVAL;
-       }
-       if (!ufstype)
-               ufstype = UFS_SB(sb)->s_flavour;
-       else if (ufstype != UFS_SB(sb)->s_flavour) {
-               pr_err("ufstype can't be changed during remount\n");
+       if (!ufs_parse_options(data, &ufstype, &on_err, true)) {
                mutex_unlock(&UFS_SB(sb)->s_lock);
                return -EINVAL;
        }