ext4: Add support for non-native signed/unsigned htree hash algorithms

The original ext3 hash algorithms assumed that variables of type char
were signed, as God and K&R intended.  Unfortunately, this assumption
is not true on some architectures.  Userspace support for marking
filesystems with non-native signed/unsigned chars was added two years
ago, but the kernel-side support was never added (until now).

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 9fd2a5e1be4d..315858db8078 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -372,6 +372,8 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
                 goto fail;
         }
         hinfo->hash_version = root->info.hash_version;
+        if (hinfo->hash_version <= DX_HASH_TEA)
+                hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
         if (d_name)
                 ext4fs_dirhash(d_name->name, d_name->len, hinfo);
@@ -641,6 +643,9 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
         dir = dir_file->f_path.dentry->d_inode;
         if (!(EXT4_I(dir)->i_flags & EXT4_INDEX_FL)) {
                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+                if (hinfo.hash_version <= DX_HASH_TEA)
+                        hinfo.hash_version +=
+                                EXT4_SB(dir->i_sb)->s_hash_unsigned;
                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
                                                start_hash, start_minor_hash);
@@ -1408,6 +1413,8 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
 
         /* Initialize as for dx_probe */
         hinfo.hash_version = root->info.hash_version;
+        if (hinfo.hash_version <= DX_HASH_TEA)
+                hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
         hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
         ext4fs_dirhash(name, namelen, &hinfo);
         frame = frames;