Missing update_pages() for zfs_write.

[lundman]

Occasionally, zfs_write appears to work but does not actually store any data on disk. export/import will sometimes fix the issue.

I am wondering if it is related to that we do not have update_pages(), as used here;

            ASSERT(tx_bytes <= uio_resid(uio));
            uioskip(uio, tx_bytes);
        }
        if (tx_bytes && vn_has_cached_data(vp)) {
            printf("we should add update_pages()\n");
            //update_pages(vp, woff, tx_bytes, zfsvfs->z_os,
            //      zp->z_id, uio->uio_segflg, tx);
        }

The FreeBSD version looks like;
http://fxr.watson.org/fxr/source/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c#L441

The Solaris version looks like;
http://fxr.watson.org/fxr/source/common/fs/zfs/zfs_vnops.c?v=OPENSOLARIS#L355

I am unsure what the OSX kernel version would look like.

[lundman]

91442ee