+enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
+
+/**
+ * fat_parse_long - Parse extended directory entry.
+ *
+ * This function returns zero on success, negative value on error, or one of
+ * the following:
+ *
+ * %PARSE_INVALID - Directory entry is invalid.
+ * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
+ * %PARSE_EOF - Directory has no more entries.
+ */
+static int fat_parse_long(struct inode *dir, loff_t *pos,
+ struct buffer_head **bh, struct msdos_dir_entry **de,
+ wchar_t **unicode, unsigned char *nr_slots)
+{
+ struct msdos_dir_slot *ds;
+ unsigned char id, slot, slots, alias_checksum;
+
+ if (!*unicode) {
+ *unicode = (wchar_t *)__get_free_page(GFP_KERNEL);
+ if (!*unicode) {
+ brelse(*bh);
+ return -ENOMEM;
+ }
+ }
+parse_long:
+ slots = 0;
+ ds = (struct msdos_dir_slot *)*de;
+ id = ds->id;
+ if (!(id & 0x40))
+ return PARSE_INVALID;
+ slots = id & ~0x40;
+ if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
+ return PARSE_INVALID;
+ *nr_slots = slots;
+ alias_checksum = ds->alias_checksum;
+
+ slot = slots;
+ while (1) {
+ int offset;
+
+ slot--;
+ offset = slot * 13;
+ fat16_towchar(*unicode + offset, ds->name0_4, 5);
+ fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
+ fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
+
+ if (ds->id & 0x40)
+ (*unicode)[offset + 13] = 0;
+ if (fat_get_entry(dir, pos, bh, de) < 0)
+ return PARSE_EOF;
+ if (slot == 0)
+ break;
+ ds = (struct msdos_dir_slot *)*de;
+ if (ds->attr != ATTR_EXT)
+ return PARSE_NOT_LONGNAME;
+ if ((ds->id & ~0x40) != slot)
+ goto parse_long;
+ if (ds->alias_checksum != alias_checksum)
+ goto parse_long;
+ }
+ if ((*de)->name[0] == DELETED_FLAG)
+ return PARSE_INVALID;
+ if ((*de)->attr == ATTR_EXT)
+ goto parse_long;
+ if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
+ return PARSE_INVALID;
+ if (fat_checksum((*de)->name) != alias_checksum)
+ *nr_slots = 0;
+
+ return 0;
+}
+