ext2: avoid rec_len overflow with 64KB block size

With 64KB blocksize, a directory entry can have size 64KB which does not
fit into 16 bits we have for entry length.  So we store 0xffff instead and
convert the value when read from / written to disk.

[akpm@linux-foundation.org: coding-style fixes]
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/ext2_fs.h b/include/linux/ext2_fs.h
index c77c3bb..0f6c86c 100644
--- a/include/linux/ext2_fs.h
+++ b/include/linux/ext2_fs.h
@@ -561,6 +561,7 @@
 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
 					 ~EXT2_DIR_ROUND)
+#define EXT2_MAX_REC_LEN		((1<<16)-1)
 
 static inline ext2_fsblk_t
 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)