cifs: mapchars mount option ignored

commit cb8b02fd6343228966324528adf920bfb8b8e681 upstream.

There are two ways that special characters (not allowed in some
other operating systems like Windows, but allowed in POSIX) have
been mapped in the past ("SFU" and "SFM" mappings) to allow them
to be stored in a range reserved for special chars. The default
for Linux has been to use "mapposix" (ie the SFM mapping) but
the conversion to the new mount API in the 5.11 kernel broke
the ability to override the default mapping of the reserved
characters (like '?' and '*' and '\') via "mapchars" mount option.

This patch fixes that - so can now mount with "mapchars"
mount option to override the default ("mapposix" ie SFM) mapping.

Reported-by: Tyler Spivey <tspivey8@gmail.com>
Fixes: 24e0a1eff9e2 ("cifs: switch to new mount api")
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index ace11a1a7c8abc07e9df9ec7e9fbf2bd61455e1c..1bda75609b6422ea0a7c7adf0a083094eefaaa5b 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -904,6 +904,14 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
                        ctx->sfu_remap = false; /* disable SFU mapping */
                }
                break;
+       case Opt_mapchars:
+               if (result.negated)
+                       ctx->sfu_remap = false;
+               else {
+                       ctx->sfu_remap = true;
+                       ctx->remap = false; /* disable SFM (mapposix) mapping */
+               }
+               break;
        case Opt_user_xattr:
                if (result.negated)
                        ctx->no_xattr = 1;