Hi,

On Mon, 2010-01-25 at 03:06 -0500, tytso@mit.edu wrote:

On Sun, Jan 24, 2010 at 11:18:47PM -0700, Andreas Dilger wrote:

quoted

It doesn't seem that ext2/3/4 are using the 0x00100000 value itself,
but it seems the VFS is using this value for FS_DIRECTIO_FL.  Should
we reserve this in the ext4 flags also, to avoid collisions?  I'm
not sure what that flag is for, possibly to force all IO to the file
to be uncached?

Hmm, absolutely nothing seems to use FS_DIRECTIO_FL; it looks like it
was introduced by GFS2 in commit 128e5eba in 2006 and then dropped in
commit c9f6a6bb in 2008, but we never killed the FS_DIRECTIO_FL flag
itself in include/linux/fs.h.

The summary line for c9f6a6bb is a bit amusing:

    [GFS2] Remove support for unused and pointless flag

Heh.

Sounds like we should just kill it.  Any objections?

					- Ted

No. Sounds good to me. It was never used with GFS2 and it a left-over
from GFS1 which had a flag allowing all "normal" I/O to be turned into
O_DIRECT I/O depending on an inode flag. The idea failed due to
alignment restrictions of course and nobody actually used it,

Steve.