fs/qnx6: Fix building with GCC 15

qnx6_checkroot() had been using weirdly spelled initializer - it needed
to initialize 3-element arrays of char and it used NUL-padded
3-character string literals (i.e. 4-element initializers, with
completely pointless zeroes at the end).

That had been spotted by gcc-15[*]; prior to that gcc quietly dropped
the 4th element of initializers.

However, none of that had been needed in the first place - all this
array is used for is checking that the first directory entry in root
directory is "." and the second - "..".  The check had been expressed as
a loop, using that match_root[] array.  Since there is no chance that we
ever want to extend that list of entries, the entire thing is much too
fancy for its own good; what we need is just a couple of explicit
memcmp() and that's it.

[*]: fs/qnx6/inode.c: In function ‘qnx6_checkroot’:
fs/qnx6/inode.c:182:41: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization]
  182 |         static char match_root[2][3] = {".\0\0", "..\0"};
      |                                         ^~~~~~~
fs/qnx6/inode.c:182:50: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization]
  182 |         static char match_root[2][3] = {".\0\0", "..\0"};
      |                                                  ^~~~~~

Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
Link: https://lore.kernel.org/r/20241004195132.1393968-1-brahmajit.xyz@gmail.com
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c
index 85925ec0051a97cf5867bbef685099cc67bb9392..3310d1ad4d0e9875872227f66a2dade02fe7f1c3 100644 (file)
--- a/fs/qnx6/inode.c
+++ b/fs/qnx6/inode.c
@@ -179,8 +179,7 @@ static int qnx6_statfs(struct dentry *dentry, struct kstatfs *buf)
  */
 static const char *qnx6_checkroot(struct super_block *s)
 {
-       static char match_root[2][3] = {".\0\0", "..\0"};
-       int i, error = 0;
+       int error = 0;
        struct qnx6_dir_entry *dir_entry;
        struct inode *root = d_inode(s->s_root);
        struct address_space *mapping = root->i_mapping;
@@ -189,11 +188,9 @@ static const char *qnx6_checkroot(struct super_block *s)
        if (IS_ERR(folio))
                return "error reading root directory";
        dir_entry = kmap_local_folio(folio, 0);
-       for (i = 0; i < 2; i++) {
-               /* maximum 3 bytes - due to match_root limitation */
-               if (strncmp(dir_entry[i].de_fname, match_root[i], 3))
-                       error = 1;
-       }
+       if (memcmp(dir_entry[0].de_fname, ".", 2) ||
+           memcmp(dir_entry[1].de_fname, "..", 3))
+               error = 1;
        folio_release_kmap(folio, dir_entry);
        if (error)
                return "error reading root directory.";