JFS: ext2 inode attributes for jfs

ext2 inode attributes with relevance for jfs:

'a' 	EXT2_APPEND_FL       -> append only
'i' 	EXT2_IMMUTABLE_FL    -> immutable file
's' 	EXT2_SECRM_FL	     -> zero file
'u' 	EXT2_UNRM_FL	     -> allow for unrm
'A' 	EXT2_NOATIME_FL      -> no access time
'D' 	EXT2_DIRSYNC_FL      -> dirsync
'S' 	EXT2_SYNC_FL	     -> sync

overview of jfs flags (partially for OS/2)

value	   (OS/2)	Linux	ext2 attrs
------------------------------------------------
0x00010000 IFJOURNAL	-
0x00020000 ISPARSE  	used
0x00040000 INLINEEA 	used
0x00080000 -	    	-	JFS_NOATIME_FL

0x00100000 -	    	-	JFS_DIRSYNC_FL
0x00200000 -	    	-	JFS_SYNC_FL
0x00400000 -	    	-	JFS_SECRM_FL
0x00800000 ISWAPFILE	-	JFS_UNRM_FL

0x01000000 -	    	-	JFS_APPEND_FL
0x02000000 IREADONLY	-	JFS_IMMUTABLE_FL
0x04000000 IHIDDEN  	-	-
0x08000000 ISYSTEM  	-	-

0x10000000 -	    	-
0x20000000 IDIRECTORY	used
0x40000000 IARCHIVE 	-
0x80000000 INEWNAME 	-

the implementation is straight forward, except
for the fact that the attributes have to be mapped
to match with the ext2 ones to avoid a separate
tool for manipulating them (this could be avoided
when using a separate flag field in the on-disk
representation, but the overhead is minimal)

a special jfs_ioctl is added to allow for the new
JFS_IOC_GETFLAGS and JFS_IOC_SETFLAGS calls.

a helper function jfs_set_inode_flags() to transfer
the flags from the on-disk version to the inode

minor changes to allow flag inheritance on inode
creation, as well as a cleanup of the on-disk
flags (including the new ones)

beforementioned helper to map between ext2 and jfs
versions of the new flags ...

the JFS_SECRM_FL and JFS_UNRM_FL are not done yet
and I'm not 100% sure they are worth the effort,
the rest seems to work out of the box ...

Signed-off-by: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>