ext3: 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>
Cc: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org

2 files changed, 28 insertions, 1 deletions

diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
index d14f02918483..9004794a35fe 100644
--- a/include/linux/ext3_fs.h
+++ b/include/linux/ext3_fs.h
@@ -354,6 +354,13 @@ struct ext3_inode {
 #define EXT3_ORPHAN_FS                  0x0004  /* Orphans being recovered */
 
 /*
+ * Misc. filesystem flags
+ */
+#define EXT2_FLAGS_SIGNED_HASH          0x0001  /* Signed dirhash in use */
+#define EXT2_FLAGS_UNSIGNED_HASH        0x0002  /* Unsigned dirhash in use */
+#define EXT2_FLAGS_TEST_FILESYS         0x0004  /* to test development code */
+
+/*
  * Mount flags
  */
 #define EXT3_MOUNT_CHECK                0x00001 /* Do mount-time checks */
@@ -489,7 +496,23 @@ struct ext3_super_block {
         __u16   s_reserved_word_pad;
         __le32  s_default_mount_opts;
         __le32  s_first_meta_bg;        /* First metablock block group */
-        __u32   s_reserved[190];        /* Padding to the end of the block */
+        __le32  s_mkfs_time;            /* When the filesystem was created */
+        __le32  s_jnl_blocks[17];       /* Backup of the journal inode */
+        /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
+/*150*/ __le32  s_blocks_count_hi;      /* Blocks count */
+        __le32  s_r_blocks_count_hi;    /* Reserved blocks count */
+        __le32  s_free_blocks_count_hi; /* Free blocks count */
+        __le16  s_min_extra_isize;      /* All inodes have at least # bytes */
+        __le16  s_want_extra_isize;     /* New inodes should reserve # bytes */
+        __le32  s_flags;                /* Miscellaneous flags */
+        __le16  s_raid_stride;          /* RAID stride */
+        __le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
+        __le64  s_mmp_block;            /* Block for multi-mount protection */
+        __le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
+        __u8    s_log_groups_per_flex;  /* FLEX_BG group size */
+        __u8    s_reserved_char_pad2;
+        __le16  s_reserved_pad;
+        __u32   s_reserved[162];        /* Padding to the end of the block */
 };
 
 #ifdef __KERNEL__
@@ -694,6 +717,9 @@ static inline __le16 ext3_rec_len_to_disk(unsigned len)
 #define DX_HASH_LEGACY          0
 #define DX_HASH_HALF_MD4        1
 #define DX_HASH_TEA             2
+#define DX_HASH_LEGACY_UNSIGNED 3
+#define DX_HASH_HALF_MD4_UNSIGNED       4
+#define DX_HASH_TEA_UNSIGNED            5
 
 #ifdef __KERNEL__
 
diff --git a/include/linux/ext3_fs_sb.h b/include/linux/ext3_fs_sb.h
index e024e38248ff..a4e9216b3a6d 100644
--- a/include/linux/ext3_fs_sb.h
+++ b/include/linux/ext3_fs_sb.h
@@ -57,6 +57,7 @@ struct ext3_sb_info {
         u32 s_next_generation;
         u32 s_hash_seed[4];
         int s_def_hash_version;
+        int s_hash_unsigned;    /* 3 if hash should be signed, 0 if not */
         struct percpu_counter s_freeblocks_counter;
         struct percpu_counter s_freeinodes_counter;
         struct percpu_counter s_dirs_counter;