Fix 64KB blocksize in ext3 directories

With 64KB blocksize, a directory entry can have size 64KB which does not
fit into 16 bits we have for entry lenght.  So we store 0xffff instead and
convert value when read from / written to disk.  The patch also converts
some places to use ext3_next_entry() when we are changing them anyway.

[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
index 6413445..241c01c 100644
--- a/include/linux/ext3_fs.h
+++ b/include/linux/ext3_fs.h
@@ -656,6 +656,26 @@
 #define EXT3_DIR_ROUND			(EXT3_DIR_PAD - 1)
 #define EXT3_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT3_DIR_ROUND) & \
 					 ~EXT3_DIR_ROUND)
+#define EXT3_MAX_REC_LEN		((1<<16)-1)
+
+static inline unsigned ext3_rec_len_from_disk(__le16 dlen)
+{
+	unsigned len = le16_to_cpu(dlen);
+
+	if (len == EXT3_MAX_REC_LEN)
+		return 1 << 16;
+	return len;
+}
+
+static inline __le16 ext3_rec_len_to_disk(unsigned len)
+{
+	if (len == (1 << 16))
+		return cpu_to_le16(EXT3_MAX_REC_LEN);
+	else if (len > (1 << 16))
+		BUG();
+	return cpu_to_le16(len);
+}
+
 /*
  * Hash Tree Directory indexing
  * (c) Daniel Phillips, 2001