HFS+: add custom dentry hash and comparison operations

Add custom dentry hash and comparison operations for HFS+ filesystems that are
case-insensitive and/or do automatic unicode decomposition.  The new
operations reuse the existing HFS+ ASCII to unicode conversion, unicode
decomposition and case folding functionality.

Signed-off-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 138 insertions, 1 deletions

diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index 90ebab753d30..050d29c0a5b5 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -62,8 +62,10 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
                 if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) &&
                     (head->key_type == HFSPLUS_KEY_BINARY))
                         tree->keycmp = hfsplus_cat_bin_cmp_key;
-                else
+                else {
                         tree->keycmp = hfsplus_cat_case_cmp_key;
+                        HFSPLUS_SB(sb).flags |= HFSPLUS_SB_CASEFOLD;
+                }
         } else {
                 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
                 goto fail_page;
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 80b5682a2273..1955ee61251c 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -36,6 +36,8 @@ static struct dentry *hfsplus_lookup(struct inode *dir, struct dentry *dentry,
         u16 type;
 
         sb = dir->i_sb;
+
+        dentry->d_op = &hfsplus_dentry_operations;
         dentry->d_fsdata = NULL;
         hfs_find_init(HFSPLUS_SB(sb).cat_tree, &fd);
         hfsplus_cat_build_key(sb, fd.search_key, dir->i_ino, &dentry->d_name);
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 3915635b4470..d9f5eda6d039 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -150,6 +150,7 @@ struct hfsplus_sb_info {
 #define HFSPLUS_SB_NODECOMPOSE  0x0002
 #define HFSPLUS_SB_FORCE        0x0004
 #define HFSPLUS_SB_HFSX         0x0008
+#define HFSPLUS_SB_CASEFOLD     0x0010
 
 
 struct hfsplus_inode_info {
@@ -321,6 +322,7 @@ void hfsplus_file_truncate(struct inode *);
 /* inode.c */
 extern const struct address_space_operations hfsplus_aops;
 extern const struct address_space_operations hfsplus_btree_aops;
+extern struct dentry_operations hfsplus_dentry_operations;
 
 void hfsplus_inode_read_fork(struct inode *, struct hfsplus_fork_raw *);
 void hfsplus_inode_write_fork(struct inode *, struct hfsplus_fork_raw *);
@@ -353,6 +355,8 @@ int hfsplus_strcasecmp(const struct hfsplus_unistr *, const struct hfsplus_unist
 int hfsplus_strcmp(const struct hfsplus_unistr *, const struct hfsplus_unistr *);
 int hfsplus_uni2asc(struct super_block *, const struct hfsplus_unistr *, char *, int *);
 int hfsplus_asc2uni(struct super_block *, struct hfsplus_unistr *, const char *, int);
+int hfsplus_hash_dentry(struct dentry *dentry, struct qstr *str);
+int hfsplus_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *s2);
 
 /* wrapper.c */
 int hfsplus_read_wrapper(struct super_block *);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 409ce5429c91..6f7c662174db 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -131,6 +131,11 @@ const struct address_space_operations hfsplus_aops = {
         .writepages     = hfsplus_writepages,
 };
 
+struct dentry_operations hfsplus_dentry_operations = {
+        .d_hash       = hfsplus_hash_dentry,
+        .d_compare    = hfsplus_compare_dentry,
+};
+
 static struct dentry *hfsplus_file_lookup(struct inode *dir, struct dentry *dentry,
                                           struct nameidata *nd)
 {
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 42570c95ad62..6d87a2a9534d 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -380,6 +380,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
                 iput(root);
                 goto cleanup;
         }
+        sb->s_root->d_op = &hfsplus_dentry_operations;
 
         str.len = sizeof(HFSP_HIDDENDIR_NAME) - 1;
         str.name = HFSP_HIDDENDIR_NAME;
diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
index 5df0052b2775..9e10f9444b64 100644
--- a/fs/hfsplus/unicode.c
+++ b/fs/hfsplus/unicode.c
@@ -314,3 +314,126 @@ int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr,
                 return -ENAMETOOLONG;
         return 0;
 }
+
+/*
+ * Hash a string to an integer as appropriate for the HFS+ filesystem.
+ * Composed unicode characters are decomposed and case-folding is performed
+ * if the appropriate bits are (un)set on the superblock.
+ */
+int hfsplus_hash_dentry(struct dentry *dentry, struct qstr *str)
+{
+        struct super_block *sb = dentry->d_sb;
+        const char *astr;
+        const u16 *dstr;
+        int casefold, decompose, size, dsize, len;
+        unsigned long hash;
+        wchar_t c;
+        u16 c2;
+
+        casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
+        decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
+        hash = init_name_hash();
+        astr = str->name;
+        len = str->len;
+        while (len > 0) {
+                size = asc2unichar(sb, astr, len, &c);
+                astr += size;
+                len -= size;
+
+                if (decompose && (dstr = decompose_unichar(c, &dsize))) {
+                        do {
+                                c2 = *dstr++;
+                                if (!casefold || (c2 = case_fold(c2)))
+                                        hash = partial_name_hash(c2, hash);
+                        } while (--dsize > 0);
+                } else {
+                        c2 = c;
+                        if (!casefold || (c2 = case_fold(c2)))
+                                hash = partial_name_hash(c2, hash);
+                }
+        }
+        str->hash = end_name_hash(hash);
+
+        return 0;
+}
+
+/*
+ * Compare strings with HFS+ filename ordering.
+ * Composed unicode characters are decomposed and case-folding is performed
+ * if the appropriate bits are (un)set on the superblock.
+ */
+int hfsplus_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *s2)
+{
+        struct super_block *sb = dentry->d_sb;
+        int casefold, decompose, size;
+        int dsize1, dsize2, len1, len2;
+        const u16 *dstr1, *dstr2;
+        const char *astr1, *astr2;
+        u16 c1, c2;
+        wchar_t c;
+
+        casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
+        decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
+        astr1 = s1->name;
+        len1 = s1->len;
+        astr2 = s2->name;
+        len2 = s2->len;
+        dsize1 = dsize2 = 0;
+        dstr1 = dstr2 = NULL;
+
+        while (len1 > 0 && len2 > 0) {
+                if (!dsize1) {
+                        size = asc2unichar(sb, astr1, len1, &c);
+                        astr1 += size;
+                        len1 -= size;
+
+                        if (!decompose || !(dstr1 = decompose_unichar(c, &dsize1))) {
+                                c1 = c;
+                                dstr1 = &c1;
+                                dsize1 = 1;
+                        }
+                }
+
+                if (!dsize2) {
+                        size = asc2unichar(sb, astr2, len2, &c);
+                        astr2 += size;
+                        len2 -= size;
+
+                        if (!decompose || !(dstr2 = decompose_unichar(c, &dsize2))) {
+                                c2 = c;
+                                dstr2 = &c2;
+                                dsize2 = 1;
+                        }
+                }
+
+                c1 = *dstr1;
+                c2 = *dstr2;
+                if (casefold) {
+                        if  (!(c1 = case_fold(c1))) {
+                                dstr1++;
+                                dsize1--;
+                                continue;
+                        }
+                        if (!(c2 = case_fold(c2))) {
+                                dstr2++;
+                                dsize2--;
+                                continue;
+                        }
+                }
+                if (c1 < c2)
+                        return -1;
+                else if (c1 > c2)
+                        return 1;
+
+                dstr1++;
+                dsize1--;
+                dstr2++;
+                dsize2--;
+        }
+
+        if (len1 < len2)
+                return -1;
+        if (len1 > len2)
+                return 1;
+        return 0;
+}