cifs: convert case-insensitive dentry ops to use new case conversion routines

Have the case-insensitive d_compare and d_hash routines convert each
character in the filenames to wchar_t's and then use the new
cifs_toupper routine to convert those into uppercase.

With this scheme we should more closely emulate the case conversion that
the servers will do.

Reported-and-Tested-by: Jan-Marek Glogowski <glogow@fbihome.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 50 insertions, 8 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index d62ce0d48141..d3e2eaa503a6 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -32,6 +32,7 @@
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
+#include "cifs_unicode.h"
 
 static void
 renew_parental_timestamps(struct dentry *direntry)
@@ -834,12 +835,17 @@ static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
 {
         struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
         unsigned long hash;
-        int i;
+        wchar_t c;
+        int i, charlen;
 
         hash = init_name_hash();
-        for (i = 0; i < q->len; i++)
-                hash = partial_name_hash(nls_tolower(codepage, q->name[i]),
-                                         hash);
+        for (i = 0; i < q->len; i += charlen) {
+                charlen = codepage->char2uni(&q->name[i], q->len - i, &c);
+                /* error out if we can't convert the character */
+                if (unlikely(charlen < 0))
+                        return charlen;
+                hash = partial_name_hash(cifs_toupper(c), hash);
+        }
         q->hash = end_name_hash(hash);
 
         return 0;
@@ -849,11 +855,47 @@ static int cifs_ci_compare(const struct dentry *parent, const struct dentry *den
                 unsigned int len, const char *str, const struct qstr *name)
 {
         struct nls_table *codepage = CIFS_SB(parent->d_sb)->local_nls;
+        wchar_t c1, c2;
+        int i, l1, l2;
 
-        if ((name->len == len) &&
-            (nls_strnicmp(codepage, name->name, str, len) == 0))
-                return 0;
-        return 1;
+        /*
+         * We make the assumption here that uppercase characters in the local
+         * codepage are always the same length as their lowercase counterparts.
+         *
+         * If that's ever not the case, then this will fail to match it.
+         */
+        if (name->len != len)
+                return 1;
+
+        for (i = 0; i < len; i += l1) {
+                /* Convert characters in both strings to UTF-16. */
+                l1 = codepage->char2uni(&str[i], len - i, &c1);
+                l2 = codepage->char2uni(&name->name[i], name->len - i, &c2);
+
+                /*
+                 * If we can't convert either character, just declare it to
+                 * be 1 byte long and compare the original byte.
+                 */
+                if (unlikely(l1 < 0 && l2 < 0)) {
+                        if (str[i] != name->name[i])
+                                return 1;
+                        l1 = 1;
+                        continue;
+                }
+
+                /*
+                 * Here, we again ass|u|me that upper/lowercase versions of
+                 * a character are the same length in the local NLS.
+                 */
+                if (l1 != l2)
+                        return 1;
+
+                /* Now compare uppercase versions of these characters */
+                if (cifs_toupper(c1) != cifs_toupper(c2))
+                        return 1;
+        }
+
+        return 0;
 }
 
 const struct dentry_operations cifs_ci_dentry_ops = {