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
This commit is contained in:
Theodore Ts'o
Родитель
8f72fbdf0d
Коммит
5e1f8c9e20
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@ -35,23 +35,71 @@ static void TEA_transform(__u32 buf[4], __u32 const in[])
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/* The old legacy hash */
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static __u32 dx_hack_hash (const char *name, int len)
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static __u32 dx_hack_hash_unsigned(const char *name, int len)
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{
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__u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
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while (len--) {
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__u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
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__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
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const unsigned char *ucp = (const unsigned char *) name;
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if (hash & 0x80000000) hash -= 0x7fffffff;
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while (len--) {
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hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
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if (hash & 0x80000000)
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hash -= 0x7fffffff;
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hash1 = hash0;
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hash0 = hash;
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}
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return (hash0 << 1);
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return hash0 << 1;
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}
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static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
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static __u32 dx_hack_hash_signed(const char *name, int len)
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{
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__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
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const signed char *scp = (const signed char *) name;
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while (len--) {
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hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
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if (hash & 0x80000000)
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hash -= 0x7fffffff;
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hash1 = hash0;
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hash0 = hash;
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}
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return hash0 << 1;
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}
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static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
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{
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__u32 pad, val;
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int i;
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const signed char *scp = (const signed char *) msg;
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pad = (__u32)len | ((__u32)len << 8);
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pad |= pad << 16;
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val = pad;
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if (len > num*4)
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len = num * 4;
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for (i = 0; i < len; i++) {
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if ((i % 4) == 0)
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val = pad;
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val = ((int) scp[i]) + (val << 8);
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if ((i % 4) == 3) {
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*buf++ = val;
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val = pad;
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num--;
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}
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}
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if (--num >= 0)
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*buf++ = val;
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while (--num >= 0)
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*buf++ = pad;
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}
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static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
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{
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__u32 pad, val;
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int i;
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const unsigned char *ucp = (const unsigned char *) msg;
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pad = (__u32)len | ((__u32)len << 8);
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pad |= pad << 16;
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@ -62,7 +110,7 @@ static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
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for (i=0; i < len; i++) {
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if ((i % 4) == 0)
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val = pad;
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val = msg[i] + (val << 8);
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val = ((int) ucp[i]) + (val << 8);
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if ((i % 4) == 3) {
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*buf++ = val;
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val = pad;
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@ -95,6 +143,8 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
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const char *p;
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int i;
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__u32 in[8], buf[4];
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void (*str2hashbuf)(const char *, int, __u32 *, int) =
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str2hashbuf_signed;
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/* Initialize the default seed for the hash checksum functions */
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buf[0] = 0x67452301;
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@ -113,13 +163,18 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
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}
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switch (hinfo->hash_version) {
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case DX_HASH_LEGACY:
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hash = dx_hack_hash(name, len);
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case DX_HASH_LEGACY_UNSIGNED:
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hash = dx_hack_hash_unsigned(name, len);
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break;
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case DX_HASH_LEGACY:
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hash = dx_hack_hash_signed(name, len);
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break;
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case DX_HASH_HALF_MD4_UNSIGNED:
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str2hashbuf = str2hashbuf_unsigned;
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case DX_HASH_HALF_MD4:
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p = name;
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while (len > 0) {
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str2hashbuf(p, len, in, 8);
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(*str2hashbuf)(p, len, in, 8);
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half_md4_transform(buf, in);
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len -= 32;
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p += 32;
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@ -127,10 +182,12 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
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minor_hash = buf[2];
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hash = buf[1];
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break;
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case DX_HASH_TEA_UNSIGNED:
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str2hashbuf = str2hashbuf_unsigned;
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case DX_HASH_TEA:
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p = name;
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while (len > 0) {
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str2hashbuf(p, len, in, 4);
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(*str2hashbuf)(p, len, in, 4);
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TEA_transform(buf, in);
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len -= 16;
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p += 16;
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@ -368,6 +368,8 @@ dx_probe(struct qstr *entry, struct inode *dir,
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goto fail;
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}
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hinfo->hash_version = root->info.hash_version;
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if (hinfo->hash_version <= DX_HASH_TEA)
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hinfo->hash_version += EXT3_SB(dir->i_sb)->s_hash_unsigned;
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hinfo->seed = EXT3_SB(dir->i_sb)->s_hash_seed;
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if (entry)
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ext3fs_dirhash(entry->name, entry->len, hinfo);
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@ -636,6 +638,9 @@ int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash,
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dir = dir_file->f_path.dentry->d_inode;
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if (!(EXT3_I(dir)->i_flags & EXT3_INDEX_FL)) {
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hinfo.hash_version = EXT3_SB(dir->i_sb)->s_def_hash_version;
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if (hinfo.hash_version <= DX_HASH_TEA)
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hinfo.hash_version +=
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EXT3_SB(dir->i_sb)->s_hash_unsigned;
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hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed;
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count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
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start_hash, start_minor_hash);
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@ -1398,6 +1403,8 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
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/* Initialize as for dx_probe */
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hinfo.hash_version = root->info.hash_version;
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if (hinfo.hash_version <= DX_HASH_TEA)
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hinfo.hash_version += EXT3_SB(dir->i_sb)->s_hash_unsigned;
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hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed;
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ext3fs_dirhash(name, namelen, &hinfo);
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frame = frames;
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@ -1744,6 +1744,18 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
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for (i=0; i < 4; i++)
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sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
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sbi->s_def_hash_version = es->s_def_hash_version;
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i = le32_to_cpu(es->s_flags);
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if (i & EXT2_FLAGS_UNSIGNED_HASH)
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sbi->s_hash_unsigned = 3;
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else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
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#ifdef __CHAR_UNSIGNED__
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es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
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sbi->s_hash_unsigned = 3;
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#else
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es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
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#endif
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sb->s_dirt = 1;
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}
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if (sbi->s_blocks_per_group > blocksize * 8) {
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printk (KERN_ERR
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@ -353,6 +353,13 @@ struct ext3_inode {
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#define EXT3_ERROR_FS 0x0002 /* Errors detected */
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#define EXT3_ORPHAN_FS 0x0004 /* Orphans being recovered */
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/*
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* Misc. filesystem flags
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*/
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#define EXT2_FLAGS_SIGNED_HASH 0x0001 /* Signed dirhash in use */
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#define EXT2_FLAGS_UNSIGNED_HASH 0x0002 /* Unsigned dirhash in use */
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#define EXT2_FLAGS_TEST_FILESYS 0x0004 /* to test development code */
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/*
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* Mount flags
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*/
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@ -489,7 +496,23 @@ struct ext3_super_block {
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__u16 s_reserved_word_pad;
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__le32 s_default_mount_opts;
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__le32 s_first_meta_bg; /* First metablock block group */
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__u32 s_reserved[190]; /* Padding to the end of the block */
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__le32 s_mkfs_time; /* When the filesystem was created */
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__le32 s_jnl_blocks[17]; /* Backup of the journal inode */
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/* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
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/*150*/ __le32 s_blocks_count_hi; /* Blocks count */
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__le32 s_r_blocks_count_hi; /* Reserved blocks count */
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__le32 s_free_blocks_count_hi; /* Free blocks count */
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__le16 s_min_extra_isize; /* All inodes have at least # bytes */
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__le16 s_want_extra_isize; /* New inodes should reserve # bytes */
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__le32 s_flags; /* Miscellaneous flags */
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__le16 s_raid_stride; /* RAID stride */
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__le16 s_mmp_interval; /* # seconds to wait in MMP checking */
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__le64 s_mmp_block; /* Block for multi-mount protection */
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__le32 s_raid_stripe_width; /* blocks on all data disks (N*stride)*/
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__u8 s_log_groups_per_flex; /* FLEX_BG group size */
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__u8 s_reserved_char_pad2;
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__le16 s_reserved_pad;
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__u32 s_reserved[162]; /* Padding to the end of the block */
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};
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#ifdef __KERNEL__
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@ -694,6 +717,9 @@ static inline __le16 ext3_rec_len_to_disk(unsigned len)
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#define DX_HASH_LEGACY 0
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#define DX_HASH_HALF_MD4 1
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#define DX_HASH_TEA 2
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#define DX_HASH_LEGACY_UNSIGNED 3
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#define DX_HASH_HALF_MD4_UNSIGNED 4
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#define DX_HASH_TEA_UNSIGNED 5
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#ifdef __KERNEL__
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@ -57,6 +57,7 @@ struct ext3_sb_info {
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u32 s_next_generation;
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u32 s_hash_seed[4];
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int s_def_hash_version;
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int s_hash_unsigned; /* 3 if hash should be signed, 0 if not */
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struct percpu_counter s_freeblocks_counter;
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struct percpu_counter s_freeinodes_counter;
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struct percpu_counter s_dirs_counter;
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